Upload
lyphuc
View
257
Download
17
Embed Size (px)
Citation preview
KASDI MERBAH UNIVERSITY OUARGLA
FACULTY OF APPLIED SCIENCES
PROCESS ENGINEERING DEPARTMENT
Dissertation
Presented to obtain a diploma of
MASTER
Specialty: Process Engineering
Option: Environmental Engineering
Presented by
CHOUIHA Hicham
MANSOURI Abd Elmalek
Theme
Publicly supported on: 30 /05/2016
In front of the jury:
ACADEMIC YEAR: 2015/2016
Ms. Ghedamsi Rebha Kasdi Merbah University Ouargla President
Mr. Achi Fethi Kasdi Merbah University Ouargla Examiner
Dr. Kahoul Fares Kasdi Merbah University Ouargla Examiner
Pr. Sakhri Lakhdar Kasdi Merbah University Ouargla Mentor
Study the Performance of Turbo-
Expander (Expander)
I
Acknowledgements
We would like to extend our thanks to our supervisor, Prof.
SAKHRI lakhdar. We would also like to thank Mr. MANSOURI Abd
Elali for helping us to pursue our Master’s research and to the present
jury for their appreciated evaluation. To all the staff of the Chemistry
Department and our sincere thanks will be to our families who stood
by our side till the end of this work.
I would like to acknowledge the support provided by
Mr.MANSOURI Abd elmalak my colleague at work, and to thank all
the staff, without you, this work would never have been finished.
Thank you!
Finally, we leave you with these immortal words, and wish all the
best for the rest of my colleague students.
“A man would do nothing if he waited until he could do it so well
that no one would find fault with what he has done”. [John Henry
Newman]
II
List of Table
Table Title Page
I-1-3-1 Gassi Touil main fields 4
I-3-1 The exploited field of GTL area 7
I-3-2 Composition of GTL raw gas by stream line 10
III-1 Some gas producers in the world (2010-2013) 45
III-2 Specifications of commercial gas 56
III-3 Uses of Liquefied Petroleum Gas in France and worldwide 61
III-4 Characteristics of Liquefied Petroleum Gas components 64
IV-7-3-1 Calculations in Expander side 74
IV-7-3-2 Calculation of 75
IV-7-3-3 Calculation of 75
IV-7-3-4 Calculating enthalpy, entropy inlet turbo-expander 76
IV-7-3-5 Enthalpy, Entropy calculations, output expander gas phase 76
IV-7-3-6 Enthalpy, Entropy calculations output expander liquid phase 77
IV-7-3-7 Actual calculation of Enthalpy, Entropy output expander gas phase 78
IV-7-3-8 Actual calculation of Enthalpy, Entropy output expander Liquid
Phase 78
III
List of Figure
Figure Title Page
I-1 Geographical situation of GTL Area 2
I-2 Carte of exploitation blocs 3
I-3 Location of different exploited fields 4
I-4 Plans production facilities of G-T-L 5
I-5 General Plan of CPF 9
I-6 Admission system and gas separation LP 11
I-7 Unit G01: Admission system and gas separation HP 12
I-8 System 470: water treatment 13
I-9 Unit G05: Booster compressor floor 14
I-10 Unit G05: Booster compressor floor 15
I-11 Unit G11: Unit of gas conditioning 17
I-12 Unit G11: Unit of gas dehydration 18
I-13 Unit G11: LPG recovery (Cryogenic) 19
I-14 Unit G11: LPG recovery (deethanizor) 20
I-15 Unit G50: residual gas compressor 21
I-16 Unit P10: unit of condensate stabilization 22
I-17 Unit P10: unit of condensate stabilization/debutanization 23
I-18 The LPG storage spheres on-spec/ off-spec 24
I-19 Reservoirs of condensate storage on-spec/off-spec 25
I-20 Unit 36V & 16V: gas metering and gas shipping Sewer 26
I-21 The generale plan of CPF unit 27
II-1 Turbo-Expander magnetic bearings CPF GT 28
II-2 Overview of Turbo-Expander 29
II-3 Turbo-expander Image 30
II-4 The different parts of Turbo-Expander 31
II-5 The detailed diagram of the Turbo-Expander 32
II-6 The detailed diagram of the Joule Thompson valve 38
III-1 Distribution of natural gas reserves in the world 42
III
III-2 Evolution of reserves of conventional natural gas (1980-2013) 43
III-3 Natural gas production capacity in the world (%) 44
III-4 The Algerian gas export routes 49
III-5 Regional demand outlook 52
III-6 Breakdown of the uses of gas in 2004 to 2020 55
IV-1 Diagram H-S side Expander 71
Abbreviation
IV
T.E: Turbo-Expander
J.T: Joule Thomson
G11-VA-32-201: Two-phase separator tank
G11-CA-32-201: Absorber
G11-GA-32-201: Interchange gas/gas
G11-GA-32-202: Interchange gas/liquid
G11-CC-32-201: Rectifying column (deethanizer)
P10-CC-21-101: Rectifying column (debutanizer)
G11-KH-32-201: Le Turbo-Expander
GTL: Gassi Touil Location
CPF: Central Production Facilities
MEG: Monoethylene glycol
LPG: Liquefied Petroleum Gas
LNG: Liquefied Natural Gas
LP: Low Pressure
HP: High Pressure
NOTATION
V
F : force N
P : pressure Kg/ cm2
V : speed m/s
A : section mm2
Q : volume flow m3/ h
m : mass flow kg /s
ρ : volume mass kg / m3
D : diameter mm
π : constante 3.14
H : enthalpy kj/ kg
S : entropy kj/ kg k
W : work Kj / Kg
MMSCMD : Million Metric Standard Cubic Meters per Day
VI
Summary Acknowledgements I
List of Table II
List of Figure III
Abbreviation IV
Notation V
Summary VI
Introduction 1
Chapter I Presentation of Gassi Touil Region
I Presentation of GTL Production Area 2
I.1 Gas Treatment and Processing General Description (GTL – CPF) 2
I.1.1 Geographical Location 2
I.1.2 Historical background of Gassi Touil field 3
I.1.3 Gassi Touil Fields 4
I.1.4 The Production Centers of Gassi Touil 5
I.2 The Production Center (OLD INSTALLATION) 5
I.2.a Oil treatment unit 6
I.2.b Gas treatment units 6
I.2.c Associated Gas recovery and reinjection Unit (URGA) 6
I.2.d Industrial water treatment unit (déshuilage) 6
I.3 Gas Processing Plant CPF 7
I.4 General Description of Process CPF GTL 10
I.5 Description of System and Gas Circulation 11
I.5.a Unit G01: admission system (LP, HP) 11
I.5.b Unit G05: Booster Compressors 13
I.5.c Unit G11: Gas conditioning 16
I.5.d Unit G11: Gas dehydration 17
I.5.e Unit G11: LPG Recovery (Cryogenic process) 18
I.5.f Unit G11: LPG Recovery (deethanizer) 19
I.5.g Unit G50: Residue Gas Compression 20
I.5.h Unit P10: Condensate stabilization 21
I.5.i LPG Storage 23
VI
I.5.j Condensate Storage 24
I.5.k Gas Export and Metering 25
I.5.l Utilities of process inside CPF 26
Chapter II Description of Turbo-expander
II.1 Introduction 28
II.2 General Description of TURBO-EXPANDER 29
II.2.1 Application 29
II.2.2 Main Characteristics 30
II.2.3 Role of New Turbo-Expander has magnetic bearings in the unit 30
II.3 Description of Parts and Main Functions of the Machine 31
II.3.1 Parts of the machine 31
II.3.2 Main functions of the machine 32
II.3.2.1 Compression function 32
II.3.2.2 Guiding function of the rotor 32
II.4 Sealing System Description of TURBO-EXPANDER 33
II.4.1 Seal gas system 33
II.5 Active Magnetic Bearings 33
II.5.1 Bearings 34
II.6 Factors Negatively Affecting The Wealth 34
II.7 Precautions and Recommendations on The TURBO-EXPANDER 35
II.7.1 Cleanliness 35
II.7.2 Pressure Tests 35
II.7.3 Effects of Methanol and Glycol to magnetic bearings 36
II.7.4 Procedure prior to the start 36
II.7.4.1 Control 36
II.7.4.2 Anti-pumping valve 37
II.7.4.3 Pneumatic systems 37
II.7.4.4 Thrust balancing system 37
II.8 Advantages and Disadvantages of TURBO EXPANDER 37
II.8.1 Advantage 37
II.8.2 Disadvantages 38
II.9 Description Valve JOULE-THOMPSON (JT) 38
II.9.1 Description 38
VI
II.9.2 Operating principle 39
II.10 Advantages and Disadvantages of Using the Valve JOULE-
THOMPSON (JT) 39
II.10.1 Advantage 39
II.10.2 Disadvantages 39
II.11 Conclusion 40
Chapter III Treatment Of Natural Gas
III.1 Natural Gas 41
III.1.1 Introduction 41
III.1.2 Natural Gas Reserves in the World 41
III.1.3 Evolution of reserves of conventional natural gas 42
III.1.4 The gas production in the world 43
III.1.5 Consumption of Natural Gas in the World 48
III.1.6 The Gas in Algeria 48
III.1.7 Outlook 49
III.1.8 Characteristics of Natural Gas 52
III.1.8.1 Density 52
III.1.8.2 Calorific value 52
III.1.8.3 Chemical composition 53
III.1.9 The different types of Natural Gas 53
III.1.10 Utilization 54
III.1.11 Processing of Natural Gas 55
III.1.12 Specification of the treated gas 56
III.2 Liquefied Petroleum Gas (LPG) 57
III.2.1 LPG in the world 58
III.2.2 LPG in Algeria 58
III.2.3 Algerian exports of the LPG 59
III.2.4 Use of the LPG 59
III.2.5 Characteristics of LPG 62
III.2.6 LPG specifications Gassi Touil (CPF) 63
III.3 The Condensate 65
III.3.1 Generality 65
III.3.2 Properties of the Condensate 65
VI
Chapter IV Thermodynamic study
IV Introduction 68
IV.1 Definitions 68
IV.2 Concept on the Relaxation 68
IV.3 Of Thermodynamics 68
IV.3.1 First law of Thermodynamics 68
IV.4 Relaxing with Production Work (TURBO-EXPANDER) G11-KH-
32-201 69
IV.5 Thermodynamic 69
IV.5.1 First law of Thermodynamics 69
IV.5.2 The specific heat of a gas mixture 69
IV.5.3 The molecular weight of a gas mixture 70
IV.5.4 The isentropic exponent 70
IV.5.5 The specific gas constant 70
IV.5.6 Compressibility factor Z 70
IV.6 Works Relaxation 72
IV.7 Method of Calculating the Efficiency of the Turbine 72
IV.7.1 Calculation of enthalpy and entropy at the entrance of the expander
and 73
IV.7.2 Calculating enthalpy, entropy discharge the output expander and
74
IV.7.3 The Actual Work of Relaxation 74
IV.8 Interpretation of Results 81
Conclusion 82
Bibliographic
Introduction
1
Introduction
Hydrocarbons are the most strategic wealth in the world; because are the motor industry and this
is why their consequences and influences are important at all levels.
The demand for natural gas comes in second place after oil, but its importance is increasing
because it is a clean energy source which does not affect the environment.
Today Sonatrach ensures the strategic missions focused on the research, production,
transportation, processing and liquefaction of natural gas, Liquefied Petroleum Gas separation and
supplying the domestic market and commercialization of liquid and gaseous hydrocarbons the
international market.
The Production division (DP) is one very important structure in Sonatrach. It operates in all the
fields of oil and gas. Regional management GTL is a DP structure, which performs development
projects, operations and raw processing field.
The first objective in Gassi Touil factory is to ensure better recovery of condensate ( or more) what
justifies the importance of using the Turbo-Expander.
To achieve lower temperatures. The TURBO-EXPANDER is widely used in gas treatment
facilities; they are indispensable in the various processes; are of considerable reliability and have
good performance and importance in the circuit of gas (separation, liquefaction…).
CHAPTER I
Presentation of
Gassi Touil
Region
Chapter I Presentation of Gassi Touil Region
2
I. PRESENTATION OF GTL PRODUCTION AREA:
I.1. Gas Treatment and Processing General Description (GTL – CPF):
I.1.1. Geographical location:
Gassi Touil is a Sonatrach oil and gas production area. It is with In-Amenas among the
oldest discovered field in Algeria. The production equipment was installed in the 60th of last
century.
The area situated in the south east of Algeria, about 1000 Km from Algiers and about 150
km from Hassi Messaoud. It administratively belongs to the Wilaya of Ouargla and goes on
170 km of length and about 105 km of width. Figure 1 shows the location of GTL area. [7]
Figure (I-1): Geographical situation of GTL Area.
Chapter I Presentation of Gassi Touil Region
3
The Algerian territory is divided in many blocs. Those different blocs are explored or
exploited either with Sonatrach alone or in join venture with international partners. The
majority of GTL fields are located within bloc # 246. The bellow carte shows this bloc and its
voisinated blocs.
Figure (I-2): Carte of exploitation blocs
I.1.2. Historical background of Gassi Touil field:
The field of Gassi Touil was discovered in 1961 after the drilling of GTLL1, this
exploration well showed the presence of gas in the reservoir Trias superior & inferior and it
was until the drilling of GTLL3, to discover the presence of oil in the Trias inferior at a depth
of 2100 m.
The drilling of GTLL4 showed also that the Trias intermediate contains oil at depths of 2020
- 2037 m.
Chapter I Presentation of Gassi Touil Region
4
The development of this field continued rapidly, during the next two years about 30 wells
were drilled and put in exploitation. The exploration and drilling took place until 1974 in order
to delineate the contours of the field. [6]
I.1.3. Gassi Touil Fields:
The area of production of Gassi Touil is composed of many fields in which the main are:
Table (I-1-3-1): Gassi Touil main fields.
Field
Number of wells
Discovered Oil Gas Total
Nezla 31 08 39 1958
Brides × 06 06 1958
Toual 01 09 10 1958
Hassi Touareg × × 00 1959
Gassi Touil 67 11 78 1961
Hassi Chergui × 14 14 1962
Gassi El Adem × 04 04 1967
Rhourde El Khlef × 03 03 1959
Total x X 187 ×
The following satellite figure shows the different fields of GTL and their locations:
Figure (I-3): location of different exploited fields.
Chapter I Presentation of Gassi Touil Region
5
I.1.4. The production centers of Gassi Touil:
The area of Gassi Touil possesses installations to treat oil and gas. They are as follow:
The old center of production CP (oil treatment).
Center of production/processing facilities CPF (Gas processing plant).
I.2. THE PRODUCTION CENTER (OLD INSTALLATION):
The plant CP of Gassi Touil was put in production in 1965. The total area of the field is
about 120 with 60 productive wells, 6 injecting wells and 11 dry or abundant wells.
The map below locates the main processing facilities on the site Gassi Touil.
Figure (I-4): Plans production facilities of G-T-L.
Description of central production :
The whole quantity of produced oil in Gassi Touil is sent towards the center of production
CP in order to be treated and stabilized. The center is composed of the following sub-unites:
Oil treatment and stabilization unit;
Gas treatment unit.
Associated gas reinjection unit (URGA).
Industrial water treatment unit (déshuilage);
Chapter I Presentation of Gassi Touil Region
6
Utilities (Power generation, service and instrument air)
Fire prevention system.
Infrastructures (safety buildings, MCB, maintenance workshop). [1]
a) Oil treatment unit:
Oil treatment and stabilization unit is composed of separation batteries that can handle
HP and MP flow rates coming from different fields. The installed capacity is about 21 850
/d.
Beside that a storage tanks are provided with a total installed capacity of 75 400 .
The sales product is export to DTR HEH via a pumping system that can deliver 1250
/h.
b) Gas treatment units:
Four small units are installed in order to recover the LNG, based on the expansion via a
turbo- expander that lowering temperature to a suitable value for the duty. The units actually
are stopped and the handled gas is sent to the new plant CPF.
c) Associated Gas recovery and reinjection Unit (URGA):
This new unit of centrifugal compressors aimed to replace the old infrastructure of
reinjection. It collects about 4,9 MMSCMD of gas coming from the different batteries of
separation and the stopped gas treatment unit. The gas is compressed up to 152 Bars and re-
injected in specified wells to maintain the pressure of the reservoir. [2]
d) Industrial water treatment unit (déshuilage):
This unit has an object to treat produced water from separation sections. The water may
contains hydrocarbons, solid particules and in suspension particules MES. The unit can treat
up to 100 /h of water. The hydrocarbons content in treated water should be less than 5%
volume basis. [2]
Utilities :
1. Fuel Gas unit:
The aim of this unit is to provide the necessary Fuel gas to different users (GT 5002),
(Sealing gas for LP compressor, feeding LP/HP flares). The gas in this unit is firstly
separated from HC liquids that may existed, then preheated and cleaned through mesh
filters. The flow rate of fuel gas is 200 000 /d at 18.5 bar.
Chapter I Presentation of Gassi Touil Region
7
2. Air production unit:
This unit is designed as a package that provides all necessary controles and commands of
operation. It is placed to produce:
Instrument air (dry / clean) at 12 bar.
Utility air (service) at 12,5 bar.
I.3. GAS PROCESSING PLANT CPF:
SONATRACH wishes to exploit its different fields of GTL in a preferment way. For this,
it has to treat and process the gathered raw gases in order to produce sales gases, LPG and
condensates that reply to all client requirements and international norms.
The surface equipment installed in CPF Gassi Touil permits the gathering, treatment,
processing and export of final products up to 12 MMCMD as a dry gas basis, coming from
54 wells in which 30 wells are already existed.[3]
The gathering system is composed of producing lines from wells to in site manifolds and
then collected in main gathering lines to CPF according to their operating pressures. We
distinguish LP trunk lines (GT+ HTG) and HP trunk lines (REK+NZ+TL).
Table (I-3-1): The exploited fields of GTL area.
Field Number of wells Wells in service
HASSI TOUAREG 9 3
RHOUDE EL KHELF 3 2
GASSI TOUIL 11 8
NEZLA 8 3
GASSI EL ADEM 2 2
BRIDES 8 1
TOUAL 13 3
TOTAL 54 22
Chapter I Presentation of Gassi Touil Region
8
The center of production (CPF - Central Processing Facilities) is designed to treat a
nominal flow rate of 12 MMCMD as a dry gas basis and it consists of the following main
units:
Inlet facilities G01.
Inlet facilities G01.
Condensate stabilization unit P10.
Residue Gas compression unit G50.
The off-site installations are the following:
Pumping, export and metering facilities.
LPG and condensate storage unit.
Flare system.
CPF utilities and chemical requirement unit.
Buildings. [1]
Different units of CPF:
Unit G01: Inlet facilities and chemical injection.
Unit G05: Booster compression Trains.
Unit G11: LPG recovery.
Unit G50: Residual gas compression.
Unit P10: Condensate stabilization.
Unit 36V & 16V: Gas metering and export pipeline. [7]
Chapter I Presentation of Gassi Touil Region
9
Figure (I-5) : General Plan of CPF.
Chapter I Presentation of Gassi Touil Region
10
Table (I-3-2): Composition of G.T.L raw gas by stream line.
Component
Mole fraction (% mole)
LP(HTG) LP(GT) HP
0.00883 0.08241 0.01581
0.00369 0.00175 0.01122
C1 0.84252 0.68978 0.77690
C2 0.06018 0.10219 0.07541
C3 0.02514 0.04350 0.02882
iC4 0.00592 0.01440 0.00628
nC4 0.00864 0.001440 0.00889
iC5 0.00446 0.00596 0.00436
nC5 0.00291 0.00490 0.00323
C6 0.00466 0.00911 0.00453
C7 0.00087 0.00197 0.00858
C8 0.00068 0.00173 0.00284
C9 0.00049 0.00088 0.00284
C10 0.00039 0.00075 0.00138
C11 0.00107 0.00073 0.00828
0.02955 0.02992 0.04176
∑ 1.00000 1.00000 1.00000
I.4. GENERAL DESCRIPTION OF PROCESS CPF GTL:
The plant Center of Production Facilities (CPF) is mainly designed to treat and process 12
MMSCMD as dry gas basis in order to produce sales Gas, LPG and condensate that satisfy
requirements and specifications. The plant can operate normally at a flow rate comprises
between 30% (3.6 MMSCMD) and 110% (13.2 MMSCMD). The availability of the plant is
94.5% (345day/year).[3]
Chapter I Presentation of Gassi Touil Region
11
I.5 DESCRIPTION OF SYSTEM AND GAS CIRCULATION:
a) Unit G01: admission system (LP, HP):
The inlet facility of CPF receives the production fluid (LP and HP) based on the pressure of
the wells (PHP=70-73 bar; PLP=29-35 bar). The purpose of slug Catcher is to receive the
anticipated gas/liquid volumes from the trunk lines and separate into the gas, hydrocarbon
liquid and water at inlet of the CPF and protect the downstream processing facilities from any
potential upsets caused by upstream conditions. Wet gas with produced water coming from
Hassi Touareg Field HT and Gassi Touil Field GT is gathered and received at finger type LP
Slug Catcher (G01-VL-20-101).
Gas from the LP Slug Catcher is sent to the Booster Compressor (G05) and Hydrocarbon
condensate separated in the LP Slug Catcher is sent to LP Slug Catcher Condensate Flash
Drum (G01-VD-20-101). Recovered hydrocarbon condensate is pumped to HP Condensate
Flash Drum (G01-VD-20-201) .Off gas and produced water are sent to LP fuel gas system and
Produced Water Flash Drum (G01-VL-20-102) respectively.
Figure (I-6) Unit G01: Admission system and gas separation LP.
Wet gas coming from Toual, Rhourde el Khlef Field REK, Nezla NZ, Gassi el-Adem Field
GEA and Brides BR fields are gathered and received at finger type HP Slug Catcher (G01-VL-
Chapter I Presentation of Gassi Touil Region
12
20-201).The gas streams from HP Slug Catcher (G01-VL-20-201) and LP Slug Catcher (G01-
VL-20-101) through Booster Compressor (G05) are combined and fed into the LPG Recovery
Unit (G11).
Hydrocarbon condensate separated in the HP Slug Catcher together with hydrocarbon
condensate from LP Flash Drum (G01-VD-20-101) is sent to HP Condensate Flash Drum (G01-
VD-20-201). Recovered hydrocarbon condensate is pumped to Condensate Stabilization Unit
(P10) through HP Slug Catcher Condensate Pump (G01-PA-20-201A/B/C). After passing through
the Condensate Feed Filter (G01-VJ-20-201A/B) and Condensate Feed Coalescer (G01-VJ-20-
202). Off gas and produced water are sent to Booster Compressor (G05) and Produced Water
Flash Drum (G01-VL-20-102) respectively. [7]
Figure (I-7) Unit G01: Admission system and gas separation HP.
Produced water from the LP Slug Catcher, LP Slug Catcher condensate flash drum, HP Slug
Catcher, HP Slug Catcher condensate flash drum and Condensate feed coalescer is sent to
Produced Water Flash Drum (G01-VL-20-102). Received produced water is sent to a CPI
separator (470-UX-44-101) While off-gas is sent to common flare. The condensate accumulation
on the produced water surface makes the discrepancy between the level measured by 20-LIT-
Chapter I Presentation of Gassi Touil Region
13
1014 (Differential pressure type) and the level measured by 20-LIT-1012 (Radar type) and the
discrepancy alarm initiate in the MCR. Then operator should check the interface level with 20-
LG-1013 and skimming the accumulated condensate as per following, if required.
Figure (I-8): System 470 water treatment.
b) Unit G05: Booster Compressors:
Gas from LP Slug Catcher (G01-VL-20-101), HP Slug Catcher Condensate Flash Drum
(G01-VD-20-201) and Stabilizer (P10-CB-21-101) overhead shall be sent to 1st Stage Suction
K.O Drum (G05-VD-23-101A/B). Liquid from the 1st stage suction K.O drum is planned to be
returned to the LP Slug Catcher Condensate Flash Drum (G01-VD-20-101) along with 2nd
stage suction and discharge K.O drums.
Compressed gas shall be cooled down to 60 °C by the Booster Compressor 1st Stage
Discharge Cooler (G05-GC-23-101A/B). 2nd Stage Booster Compressor (G05-KA-23-102A),
which is a constant speed motor driven centrifugal type, compress the gas from 2nd stage
suction K.O drum (G05-VD-23-102A/B) up to 71,0 bars. Compressed gas is cooled down to
60 by Booster Compressor 2nd Stage Discharge Cooler (G05-GC-23-102A/B) which has a
Chapter I Presentation of Gassi Touil Region
14
fixed motor. Then the cooled compressed gas is sent to the LPG Recovery Unit (G11) through
Stage Discharge K.O. Drum (G05-VD-23-103A/B).
Condensed liquid from Stage Suction K.O Drum and Discharge K.O. Drum is combined
with condensate liquid from 1st Stage Suction K.O Drum and returned to LP Slug Catcher
Condensate Flash Drum (G01-VD-20-101).
Figure (I-9) Unit G05: Booster compressor floor.
Chapter I Presentation of Gassi Touil Region
15
Figure (I-10) Unit G05: Booster compressor floor.
Chapter I Presentation of Gassi Touil Region
16
c) Unit G11: Gas conditioning:
The combined gas streams from HP Slug Catcher (G01) and Booster Compressor (G05) pass
through Deethanizer Side Reboiler (G11-GA-32-205) tube side where its temperature is
reduced. Wet gas / Residue gas heat exchanger (G11-GA-32-206) is also provided in parallel
with Deethanizer Side Reboiler (G11-GA-32-205) to reduce dehydrator inlet temperature. The
gas then enters the Dehydrator Feed Gas Separator (G11-VA-24-101).
A recycle line is provided from the Residue Gas Cooler (G50-GC-27-101A/B) outlet to the
Inlet of Deethanizer Side Reboiler (G11-GA-32-205) for Startup, turndown and dehydrator
regeneration gas back-up operation. Design flow rate for this line is 30% of nominal flow rate
for LPG recovery unit. Condensate collected in Dehydrator Feed Gas Separator (G11-VA-24-
101) is sent to HP Slug Catcher Condensate Flash Drum (G01-VD-20-201). Gas from the Feed
Gas Separator (G11-VA-24-101) is sent to Mercury Adsorber (G11-VW-24-101). The purpose
of the mercury adsorber is to reduce Hg concentration in process gas from 10,000 ng/N in
feed to less than 10 ng/N in outlet gas to the downstream system. Mercury removal protects
the Expander (G11-KH-32-201) and Expander Compressor (G11-KA-32-201) impeller (which
are made of aluminium) against corrosion.
Gas from the mercury adsorber enters the Dehydrator Feed Gas Filter/ Coalescer (G11-VJ-
24-101). Liquid collected in Dehydrator Feed Gas Filter/ Coalescer (G11-VJ-24-101) is sent to
HP Slug Catcher Condensate Flash Drum (G01-VD-20-201). [7]
Chapter I Presentation of Gassi Touil Region
17
Figure (I-11) Unit G11: Unit of gas conditioning.
d) Unit G11: Gas dehydration:
Gas after passing through Dehydrator Feed Gas Filter/ Coalescer (G11-VJ-24-101) enters
two out of the three Gas Dehydrators (G11-VK-24-101A/B/C). The dehydration system is
designed to remove water from the gas to less than 0.1 ppm by means of molecular sieve bed
dehydrators, preventing hydrates formation in the cold section of the process.
The control logic for the dehydration process is set so that two dehydrators are adsorbing
while one is in regeneration cycle.
Once dehydrated, the gas passes through Dehydrated Gas Dust Filter (G11-VJ-24-102A/B)
which collects any fines that may come from the dehydrators. If not filtered, this dust could
cause plugging in downstream equipment. One filter is in service while the other is spare.
The regeneration gas flow through regeneration circuit is attained by means of Regeneration
Gas Compressor (G11-KA-24-101). After the gas is compressed, it is heated (using hot oil as
the heating media) in Regeneration Gas heater (G11-GA-24-101A/B/C) reaching the
temperature required to vaporize the moisture from the water saturated sieves. The hot
regeneration gas flows upward through the dryers desorbing the water. The regeneration gas is
cooled in fin fan Regeneration Gas Cooler (G11-GC-24-101), where water is condensed and
separated in Regeneration Gas Water Separator (G11-VD-24-101). Gas from Regeneration Gas
Water Separator (G11-VD-24-101) enters the tube side of Deethanizer Side Reboiler (G11-GA-
Chapter I Presentation of Gassi Touil Region
18
32-205) along with combined gas streams of G01 and G05. Whereas, liquid collected in
Regeneration Gas Water Separator (G11-VD-24-101) is sent to HP Slug Catcher Condensate
Flash Drum (G01-VD-20-201).
Figure (I-12) Unit G11: Unit of gas dehydration.
e) Unit G11: LPG Recovery (Cryogenic process):
After the inlet gas has been dehydrated, a part of it enters the tube side of Feed Gas/ Cold
Residue Gas Heat Exchanger (G11-GA-32-201A/B) where it is cooled in cross exchange
with cool residue gas coming from the tube side of Deethanizer O/H Condenser (G11-GA-
32-203) while the remaining part is cooled in the tube side of Feed Gas/ Feed Separator
Liquid Heat Exchanger (G11-GA-32-202A/B). The gas then enters the Expander Feed
Separator (G11-VA-32-201) which provides separation of the liquid condensed from the feed
gas during cooling.
Chapter I Presentation of Gassi Touil Region
19
Figure (I-13) Unit G11: LPG recovery (Cryogenic).
The liquid removed in the Expander Feed Separator (G11-VA-32-201) is flashed on level
control to the shell side of Feed Gas/ Feed Separator Liquid Heat Exchanger (G11-GA-32-
202A/B) where it provides cooling to the remaining part of inlet gas stream before feeding the
Deethanizer (G11-CC-32-201) at its lowest mid-column feed position. The vapors leave the
Expander Feed Separator (G11-VA-32-201) through a vane pack and flows to Expander (G11-
KH-32-201). In Expander, the gas expansion results in cooling of the stream and also work
extracted is used for running Expander Compressor (G11-KA-32-201). The Expander discharge
stream then flows to Absorber (G11-CA-32-201) column as feed near the bottom.
f) Unit G11: LPG Recovery (deethanizer):
The liquid at Absorber (G11-CA-32-201) bottom is sent to the top of Deethanizer (G11-CC-
32-201) as reflux; this reflux liquid condenses propane and heavier hydrocarbons from the
vapors leaving the Deethanizer overhead. The overhead vapor stream coming out of the
Deethanizer (G11-CC-32-201) is cooled and partially condensed in the shell side of Deethanizer
O/H Condenser (G11-GA-32-203), by cross-exchange with the cold Absorber (G11-CA-32-201)
overhead gas and then fed to the Absorber as reflux, this reflux liquid condenses propane and
heavier hydrocarbons coming up the Absorber column, thereby increasing the concentration of
ethane in the overhead gas. The overhead gas temperature is also reduced due to heat of
absorption effect. In the lower section of the Deethanizer (G11-CC-32-201) hot vapors
generated by Deethanizer Reboiler (G11-GA-32-204) and Deethanizer Side Reboiler (G11-GA-
32-205) strip the ethane and lighter components from the liquid flowing down the column.
Sufficient stripping vapor is generated to maintain the C2/C3 molar ratio.
Chapter I Presentation of Gassi Touil Region
20
The temperature of vapors from Deethanizer Reboiler (G11-GA-32-204) is adjusted by means
of hot oil circulation through the Deethanizer Reboiler. The bottom LPG rich stream is sent by
level control to Condensate Stabilizer/Debutanizer Unit (P10).
Figure (I-14) Unit G11: LPG recovery (deethanizor).
g) Unit G50: Residue Gas Compression:
At the absorber top the residue gas ensures first the cooling and partial condensation of of the
vapor coming from deethenizer overhead (G11-GA-32-203), as previously described.
This unit consists of two identical process trains (Gas Turbine driven Residue Gas
Compressor: 2 x 50.
During the gas processing, the pressure is reduced to achieve products objectives and
therefore, in order to export the residual gas product, the pressure must be increased allowing
the gas to be transferred.
The Residue Gas Compressor (G50-KA-27-101A) type is centrifugal driven by a gas turbine
SGT400 (G50-DT-27-101A/B). Gas enters to Residue Gas Compressors Suction Scrubber
where any remaining liquid is separated. After compression stage (up to around 70.8 bar), the
gas is cooled. It shall be ensured that the temperature is below the maximum export gas
temperature downstream Residue Gas Cooler. The gas is then exported via the pipeline and, in
Chapter I Presentation of Gassi Touil Region
21
the case of low plant feed rates, a recycle line is provided from the Residue Gas Cooler (G50-
GC-27-101A/B) outlet to the Inlet of Deethanizer Side Reboiler (G11-GA-32-205) for Start Up,
turndown and dehydrator regeneration gas back-up operation. Design flow rate for this line is
30% of nominal flow rate for LPG recovery unit. Residue gas from Residue Gas Compressor
(G50-KA-27-101A) suction is normally sent to Fuel Gas System (410) where it is used as HP
fuel gas.
Figure (I-15): Unit G50: residual gas compressor.
h) Unit P10: Condensate stabilization:
Recovered hydrocarbon condensate from HP Slug Catcher Condensate Flash Drum (G01-
VD-20-201) is pumped to condensate stabilization unit (P10) using one HP Condensate flash
drum Pump (G01-PA-20-201A/B/C). The condensate passes through the Condensate Feed
Filter (G01-VJ-20-201A/B) and condensate Feed Coalescer (G01-VJ-20-202) before entering
P10 Unit.
The liquid feed is then passed through the shell side of Stabilizer Feed Pre-heater (P10-GA-
21-101A/B) where it is heated by condensate product from tube side of Debutanizer Feed
Preheater (P10-GA-21-103) and then fed to Stabilizer Column (P10-CB-21-101) to
eliminate light ends
Chapter I Presentation of Gassi Touil Region
22
The stabilizer OVHD gas from Stabilizer Column (P10-CB-21-101) is routed to the LP
Fuel Gas system (410) or sent to booster compressor area (G05) for recompression via 21-
PIC-1005 split range control. The stabilized liquid from Stabilizer Column (P10-CB-21-
101) bottom enters the top tray of the stripping section of Debutanizer (P10-CC-21-
101) as Feed. Also the recovered liquid from Deethanizer (G11-CC-32-201) bottom
in LPG Recovery Unit (G11) after passing through the shell side of Debutanizer Feed
Pre-heater (P10-GA-21-103) is fed to Debutanizer (P10-CC-21-101) to separate LPG and
condensate.
Figure (I-16) Unit P10: unit of condensate stabilization.
Chapter I Presentation of Gassi Touil Region
23
Figure (I-17) Unit P10: unit of condensate stabilization/debutanization.
i) LPG Storage:
On-specification LPG after passing through Debutanizer O.H. Condenser (P10-GC-21-101)
and Debutanizer O.H. Receiver (P10-VA-21-101) is pumped through Debutanizer Reflux Pump
(P10-PA-21-101A/B) to LPG on-specification Storage Spheres (31G-RD-33-101A/B). Off
specification LPG if produced due to any abnormal operation must be diverted to LPG off
specification storage sphere (39G-RD-33-101) through Debutanizer Reflux Pump (P10-PA-21-
101A/B). Off specification LPG is sent back to HP Slug Condensate Flash Drum (G01-VD-20-
201) for reprocessing. [7]
Chapter I Presentation of Gassi Touil Region
24
Figure (I-18): the LPG storage spheres on-spec/ off-spec.
j) Condensate Storage:
On specification Condensate is routed to Condensate Product Storage tanks (31C-RA-35-
101A/B) after passing through tube side of Debutanizer Feed Pre-heater (P10-GA-21-103), tube
side of Stabilizer Feed Pre-heater (P10-GA-21-101 A/B) and air fin fan cooler Condensate
Rundown Cooler (P10-GC-21-102). In case of Off-specification condensate production, it must
be diverted to Condensate off specification Tank (39C-RM-35-101).
Off specification Condensate is sent back to HP Slug Condensate Flash Drum (G01-VD-20-
201) for reprocessing.
Chapter I Presentation of Gassi Touil Region
25
Figure (I-19): reservoirs of condensate storage on-spec/off-spec.
k) Gas Export and Metering:
Residue gas from Residue gas cooler (G50-GC-27-101A/B) is routed to Metering Station for
Residue Gas (36V-JX-27-101) and then to Residue Gas Export Pipeline. Residue Gas Export
Pipeline consists of Pig Launcher for Residue Gas Export Pipeline (16V-VM-34-101) and Pig
Receiver for Residue Gas Export Pipeline (16V-VM-34-102). During start up Residue Gas from
the export pipeline is sent back to the Fuel Gas System (410) as a source and also to the Flare
system (800) as emergency backup for flare pilot and backup.[7]
Chapter I Presentation of Gassi Touil Region
26
Figure (I-20): Unit 36V & 16V: gas metering and gas shipping Sewer.
l) Utilities of process inside CPF:
The utilities are very important within the CPF in order to ensure the supply of all necessary
requirements for startup and normal operation. The main utilities are:
Unit 410: Fuel gas system, which has to satisfy the norms required by Gas turbine and
the heater.
Unit 420/430: Instrument and plant air system / inert gas system.
Unit 440: Diesel Fuel System.
Unit 460: Sanitary Water System.
Unit 470: Waste water treatment system.
Unit 480: Hot oil system which has to satisfy the requirement to operate the plant in
accordance to specifications (LPG recovery, condensate stabilization…).
Unit 800: Flare system and burn pit.
Unit 0C1: Closed/open drain system.
Unit 6P0/BID: Emergency diesel generators.
Unit 4A0/4P0: Utility water / potable water system
On average 300 hours / year. As they consume respectively 660 l / h and 118.6 l / h diesel,
total consumption is expected to reach 234 / year. [7]
Chapter I Presentation of Gassi Touil Region
27
Figure (I-21): THE GENERALE PLAN OF CPF UNIT.
CHAPTER II
Description of
Turbo-expander
Chapter II Description of Turbo-expander
28
DESCRIPTION OF THE TURBO-EXPANDER:
II.1. INTRODUCTION
The raw gas treatment process at the CPF unit Gassi Touil region in particular section
recovery of LPG called G11. One of the instruments that make up this unit is the new
expansion turbine or turbo-expander with magnetic bearings, saw its interest increase as
energy recovery turbine, and it is most certain types of designs facilities without this machine.
The success of its implementation is mainly due to its high efficiency and high reliability of
operation where the greater use of Turbo-Expander in industry is for condensation of gas
mixtures to recover the heavy fractions of such mixtures.
In this chapter we present the general operation of Turbo-Expander of magnetic bearings,
Figures (II.1) and (II.2) give an overview of the Turbo-Expander.
Figure (II-1): Turbo-Expander magnetic bearings CPF GT.
Chapter II Description of Turbo-expander
29
II.2. GENERAL DESCRIPTION OF TURBO-EXPANDER:
A turbo-expander or expansion turbine is a machine that converts the energy of a gas or
steam into mechanical work during its expansion in the turbine. This expansion is being very
quickly. This greatly reduces the amount of heat transferred to or received by the system, and
therefore in agreement with the first law of thermodynamics, the internal energy of the gas
decreases when it is relaxed which results in a large temperature drop that .This then makes
the Turbo-Expander a producing machine of the cold (in the refrigeration circuit) or
producing mechanical work in the power circuits. Figure (II.2) provides an overview of the
Turbo-Expander. [1]
Figure (II-2): Overview of Turbo-Expander.
II.2.1. Application:
Cryogenic:
Energy recovery on oil fields
Air separation and liquefaction ,
Purification of gas: , He
Methane recovery and LPG from natural gas
Liquefaction of natural gas. [6]
Chapter II Description of Turbo-expander
30
II.2.2. Main characteristics:
The reaction turbine has a radial inlet and axial exhaust.
Recovery is usually performed in a single expansion stage at high speed is between [10 to
50,000 r / min] for medium and high powers [45 70 000 r / min] for low power: <50 kW. Its
power range for oil installations ranges from [50-60000 kW], It has a good isentropic
efficiency:
From 80 to 86%, it decreases if the expansion ratio increases, with conservation of the
efficiency variable load by use of blades guiding movable to the inlet (possibility of variation
of load: 50 to 120% of nominal flow rate) and good tolerance to the presence of condensate
and solid particles, and an energy recovery favored by low inlet temperatures. [1]
II.2.3. Role of New Turbo-Expander has magnetic bearings in the unit:
The Turbo-Expander presented in Figure (II.3) functions to recover energy that occurs
when a high-pressure gas passes through the turbine to reduce the pressure (isentropic
expansion).
Figure (II-3): turbo-expander Image.
Chapter II Description of Turbo-expander
31
The expansion of the gas lowers the temperature below that obtained by the Joule-
Thomson effect so it can recover a large amount of liquid. This energy is intended to drive the
compressor to increase gas pressure before being sent as gas sales.
II.3. DESCRIPTION OF PARTS AND MAIN FUNCTIONS OF THE
MACHINE:
II.3.1. Parts of the machine:
As shown in Figure (II.4), the turbo-expander is mainly comprised of:
A turbine.
A compressor.
Circuit of seal gas.
A control panel.
Table signaling parameters.
Figure (II-4): The different parts of Turbo-Expander.
Chapter II Description of Turbo-expander
32
II.3.2. Main functions of the machine:
II.3.2.1. Compression function:
Gas enters the compressor through the suction tube and arrives via a distribution channel to
the first wheel. It then passes through a set of moving parts, the wheels and the fixed parts,
broadcasters and return channels. The gas is discharged to the output of the last diffuser in the
volute and the discharge connection.
II.3.2.2. Guiding function of the rotor:
The wheels are mounted on the shaft and together form the rotor to be guided rotatably and
axially. The axial compensation is automatically performed to all of the shaft speeds.
Figure (II-5): The detailed diagram of the Turbo-Expander.
Chapter II Description of Turbo-expander
33
II.4. SEALING SYSTEM DESCRIPTION OF TURBO-EXPANDER:
The Turbo-Expander is designed for relaxation and compression of natural gas, it consists
of a Turbo-Expander to a floor loaded by a centrifugal compressor, at the opposite end of the
shaft of the Expander. Mounted on a steel support. The Expander compressor is equipped
with complete systems of sealing gas. [2]
II.4.1. Seal gas system:
The Turbo-Expander is supplied with sealing gas from the discharge of the product gas
from the compressor during normal operation of the machine, as it is also supplied from the
dry gas joint network of the three trains, the latter source power is provided to maintain a
desired pressure of the sealing gas system also is useful during startup of the machine in the
expander, the production gas contained around the shaft by a labyrinth located between
bearings, thrust and back of the compressor and turbine wheels. The turbine exhaust pressure
is higher than the compressor inlet pressure, is the pressure on the back of the turbine wheel
which is used to control the injection pressure of the sealing gas injected at the labyrinth will
flee to the back of the compressor and turbine wheels, And to the bearings for completing
dual role:
Thermal barrier to protect the bearings.
Barrier for avoiding oil to it, and to keep the parts of the machine cold.
The previous Figure (II.5) shows the sealing system of the Turbo-Expander.
II.5. ACTIVE MAGNETIC BEARINGS:
An active magnetic bearing is an electromagnetic device that maintains the relative
position of one revolving assembly (rotor) with respect to a fixed part (stator).
Electromagnetic forces implemented are controlled from an electronic control unit.
Therefore, an active magnetic bearing consists of two distinct parts, the bearing itself and the
electronic control system.
Chapter II Description of Turbo-expander
34
II.5.1. Bearings:
Each compressor-expander comprises an active magnetic bearing system. This system
includes two radial magnetic bearings, active magnetic bearings abutment in both directions,
two sets of auxiliary bearings, all necessary position sensors, a speed sensor and a control
system. The auxiliary bearings used are pairs of pre angular contact ball bearings with
ceramic balls loaded. When the rotor is not in magnetic levitation, it is supported at its ends
by a pair of these ball bearings. Note that the start cycles and making the normal case does not
involve auxiliary bearings. The control unit ensures the rotor position control and provides
instrumentation signals required for the control and protection of the machine. View details of
the system in the C3 level, "Schema piping and instrumentation". As the support of the rotor
depends on proper operation of the control unit, it must be connected to a power supply
system for battery failure (UPS- Uninterruptable Power Supply) installed inside the cabinet
AMB.
Magnetic bearings and position sensors are mounted inside the bearing housing of the
turbo expander-compressor. The electronic control system is installed in the control room (a
non-hazardous area) and connected to the magnetic bearings by electric cables. [6]
II.6. FACTORS NEGATIVELY AFFECTING THE WEALTH:
The presence of water in the natural gas and the operating conditions, high pressure and
low temperature in a raw gas treatment process are parameters that can promote the formation
of hydrates (ice), a phenomenon that can affect the normal development the process and good
recovery of liquid hydrocarbons, causing clogging of pipes and equipment (poor separation in
the balloons, poor regulation valves ... etc).
To prevent hydrate formation, an injection of glycol was provided under various rights at
low temperatures or other method by adsorption dryers molecular sieves. But a second factor
can also occur and adversely affect the recovery of heavy hydrocarbons; this phenomenon is
called foaming and caused by the presence:
-Of solid non eliminated prior suspension.
Corrosion inhibitor in conjunction with other chemicals.
Of Salts.
Chapter II Description of Turbo-expander
35
There are other problems with the balloons, which are mechanical in nature and can cause
this phenomenon, it is:
Of Demisters (sieve) deteriorated.
Of Baffles displaced from their normal position.
From Detached deflector.
As can be also favored by a high rate of hydrocarbons (turbulence). [1]
To remedy the problem of icing should be done:
Strict control of injection rates calculated based on the amount charged .
A clearing of methanol injectors.
A momentary injection of methanol in frosted points.
A hot regime.
With regard to the remedy the problem of foaming must be:
Injecting an antifoaming agent.
Purge float cages (if the foam is in the balloons) liquid hydrocarbons.
Make a hot regime.
II.7. PRECAUTIONS AND RECOMMENDATIONS ON THE TURBO-
EXPANDER:
Observe the precautions / following recommendations to avoid any risk of damage to the
turbo-expander.
II.7.1. Cleanliness:
All pipes and other openings to the turbo-expander must be protected against the ingress of
contaminants because even the smallest foreign objects can cause serious damage to internal
parts of critical tolerances. Similarly, moisture may accelerate the electrolytic action on the
rotating parts and other surfaces and damage critical internal organs. Shipping plugs provided
must remain in place until the connections to the pipes of the plant are made.
II.7.2. Pressure tests:
Chapter II Description of Turbo-expander
36
The sealing in situ testing of the compressor-expander must be carried out with the help of
our service operator. After purging with nitrogen, the pressurization takes place by means of
the housing of the pressure equalization circuit. Take particular care to avoid penetration of
foreign bodies in the control system and sealing, bearings, game pads and sealing areas of the
rotor. This accidental contamination can result from a pressure build-up or excessively rapid
decompression. In case of known or suspected contamination, the machine and the barrier gas
circuit must be completely disassembled to be checked and cleaned. To prevent damage to the
trim, high differential pressures across the linings should be avoided. [1]
The pressure rise rate should not exceed 2 to 3.5 bar (30 to 50 psi) per minute.
II.7.3. Effects of Methanol and Glycol to magnetic bearings:
Glycol and methanol are often used in the processes to turbo-expander to prevent hydrate
formation during cryogenic expansion. In the case of plants turbo regulators with magnetic
bearings, keep in mind that exposure to glycol and methanol resulted in the failure of
windings and magnetic bearing sensors .As the process gas is used as "barrier gas", for
cooling the magnetic bearings during operation, it is essential to ensure that the process gas
used as a barrier gas contains no glycol or methanol. In addition, it is important that during
the pressurization, starting and stopping the process control sequence is such that no glycol or
methanol comes into contact magnetic bearings. [2]
II.7.4. Procedure prior to the start:
The majority of the compressor-expander problems occur during the initial start-up period
of the plant. This critical period usually lasts several weeks since the initial launch of the
regulator until the temperature and pressure of the installation are standardized and all
associated equipment is stabilized.
II.7.4.1. Control:
During transport, installation and operation, pipe fittings and flange bolts may loosen.
Check and tighten if necessary. Check that all electrical circuits, switches, sensors, controls
and safety devices are properly connected, adjusted and operational. Check that all shutdown
systems are operational.
Chapter II Description of Turbo-expander
37
This system is integrated security. Therefore, verify that the loss of pneumatic signals has the
effect of closing the shutoff valve.
See controls operation of external devices in the tender documentation attached providers.
Check that all pneumatic systems and components are properly set, connected and
operational.
II.7.4.2. Anti-pumping valve:
Check that all electrical connections and devices pneumatic are correct and tight.
II.7.4.3. Pneumatic systems:
Check that all pneumatic systems and components are properly set, connected and
operational.
II.7.4.4. Thrust balancing system:
Due to the nature of the magnetic bearings, each axial bearing exerts a force of about 40%
capacity (21.3 KN or 4800 lb to 13 A), even in the absence of external loads. If, for example,
an external axial load of 1.8 kN (400 lbs) is applied to the rotor, one of the axial bearings its
load decrease from 21.3 to 19.5 kN (4 800-4 600 lbs), while the other bearing will increase
the own of 21.3 to 23.1 kN (4 800-5 000 lbs), which has the effect of keeping the rotor at
substantially the same location while absorbing all of the filler external 1.8 kN (400 lb). As
electronics at extremely high throughput, magnetic bearings have good capacity to respond to
transient loads.
II.8. ADVANTAGES AND DISADVANTAGES OF TURBO EXPANDER:
II.8.1. Advantage:
The advantages of using a Turbo Expander are:
Used in the methods of treatment, separation and gas liquefaction.
It ensures a good performance compared with other relaxation systems.
It brings a better recovery of the condensable fractions of natural gas.
Utilization of work provides by relaxation to feed the compressor.
Their large production capacity (for large facilities).
Chapter II Description of Turbo-expander
38
II.8.2. Disadvantages:
The disadvantages brought by the use of a Turbo Expander are:
It confronts the mechanical wear problem, like any rotating machinery.
High cost of installation linked to the material used and in the manufacture of these
elements.
Cooling problem related to the very low temperature.
Forming droplets that can abyss the fins of the Expander. [3]
II.9. DESCRIPTION VALVE JOULE-THOMPSON (JT):
II.9.1. Description:
This is a valve which has the role of relaxing the gas passing through it, it is composed of a
valve body assembly in which the fluid flows, the control mechanism, the actuator which
controls the flow and Accessories specific to each particular application. Sealing is provided
by headquarters, gaskets and seals. The connector nut connects the rod to the control shaft of
the actuator. The internal parts of the valve assembly body are characterized by their
simplicity and effectiveness. The fluid passes through the stack from the outside in and flows
to the outlet port. [1]
The figure below shows the model of a valve Joule Thompson.
Figure (II-6): The detailed diagram of the Joule Thompson valve.
Chapter II Description of Turbo-expander
39
II.9.2. Operating principle:
Stacking allows flow variations while limiting the velocity of flow through the element,
the stack consists of a number of disks in which the labyrinths have been drilled so as to allow
a predetermined flow rate.
The passage independence is developed by a series of bends at right angles, each passage
having a determined number of bends to limit the velocity to the expected value. Each disc
having a given capacity, the total flow through the element can be easily conducted and
controlled accurately. The piston position within the stack determines the flow rate by reading
more or less passages in the discs. [3]
A maximum flow rate being determined for each disk, the control element can operate at a
fixed velocity and settled on the whole field of design capacity, to minimize velocity changes
that normally produce noise, spray, cavitation, vibration and erosion.
II.10. ADVANTAGES AND DISADVANTAGES OF USING THE VALVE
JOULE THOMPSON (JT):
II.10.1. Advantages:
Light process (no rotating machines).
Insensitive to changes in gas flow rates to be treated.
Low investment.
Dehydrates the gas simultaneously.
II.10.2. Disadvantages:
Low liquid recovery (only ).
Sensitive to variations in pressure of the gas to be treated.
Requires a high upstream pressure.
Requires injection of an inhibitor to prevent the formation of hydrates.
The gas pressure is greatly lowered.
Chapter II Description of Turbo-expander
40
II.11. CONCLUSION:
In this chapter we conclude that the study of any industry machine requires complete mastery
of how it first secondly taking account of all constraints related to the operation and of the
role of this machine in the process.
CHAPTER III
Treatment of
Natural Gas
Chapter III Treatment of natural gas
41
III.1. NATURAL GAS:
III.1.1. Introduction
Broadly, any natural substance that is in the gaseous state under normal temperature and
pressure is a gas. These substances are reduced in number and those that are found in the
earth's crust are more limited: it is essentially saturated hydrocarbons of a lower carbon
number five, carbon dioxide, nitrogen, hydrogen sulfide, hydrogen, helium and argon.
Natural gas is playing increasing role energy. The importance of these reserves and its
advantages on the environmental plan promotes its use. Especially in high value added
sectors: Precision Industry electricity production. The implementation of this energy is based
on the technical mastery of the entire gas chain, ranging from extraction to users through
storage, transportation and distribution.
III.1.2. Natural Gas Reserves in the World:
About 2/3 of the world's proven natural gas reserves, the duration of life at current
consumption is 60 years, are concentrated in Russia and the Middle East (Iran and Qatar).
With the discovery of new fields (particularly in the offshore zone of Asia / Oceania) and the
revaluation of existing fields outside Europe, global reserves increased by 30% during the
past decade. [3]
In Europe: however, reserves fell by 40%, mainly as a result of the rapid depletion of
deposits in the North Sea. Offshore reserves have gained importance, they now account for
40% of global gas reserves.
Beyond the reserves, there is a significant potential for conventional gas resources remaining
to be developed and which would represent about 120 years of consumption. In the future, the
Middle East and the CIS (Commonwealth of Independent States) should cover an increasing
share of world gas production.
In 2011, production of Russia recorded a strong increase of 3% and the country is the second
largest producer after the United States with a share of 19% of the global volume. This
country should quickly regain its leading position worldwide in 2035. The countries of the
Chapter III Treatment of natural gas
42
Caspian Sea (Black Sea), Turkmenistan at the head, will also play an important role. In 2011,
gas production in Turkmenistan jumped dramatically from over 40% to meet the external
needs (China).
The Middle East is rapidly strengthening its role as a producer and exporter on the
international stage. Under the leadership of Qatar, this region experienced growth fastest
production last 5 years and has become an export area size providing 16% of the international
market in 2011. With over 40% of world reserves, this region occupies a central position
between Europe and Asia, has a key role to play in the global gas balance. [3]
It should also be noted the rise in production in China, the US and Australia. With a
prodigious development of its unconventional gas, the US has downgraded Russia becoming
the largest producer in 2009. Their production will continue to increase rapidly, enhancing
their export potential to internationally.
Figure (III-1): Distribution of natural gas reserves in the world.
III.1.3.Evolution of reserves of conventional natural gas:
Proved reserves are those quantities of conventional natural gas from known accumulations
which according to geological information and current technological advances, have a high
Chapter III Treatment of natural gas
43
probability of being exploited in the future, within the existing technical and economic
conditions.
The conventional natural gas reserves are important and estimates of their size continues to
evolve as new exploration or extraction techniques are discovered.
Resources are relatively well distributed worldwide. At present, Russia, Qatar and Iran share
nearly 50% of proved reserves; the Middle East has experienced the sharpest increase in
recent years.
Several analyzes estimate that most of the conventional natural gas yet to be discovered.
The world's proven reserves have doubled in 20 years to reach 186,000 billion cubic meters.
Figure (III-2): Evolution of reserves of conventional natural gas.
III.1.4. The gas production in the world:
World production of natural gas is increasing steadily for 40 years. It tripled between 1970
and 2010.
In the largest producers in 2013 were the United States with 20% of world production
(including unconventional natural gas), Russia (18%), Qatar (5%), Iran (5%) and Canada
(4%).[3]
Chapter III Treatment of natural gas
44
2/3 of the world production is provided by 10 countries. It is important to note that if the
Middle East accounts for almost 43% of proven world reserves, it represents only 17% of
world production.
Figure (III-3): Natural gas production capacity in the world (%)
Chapter III Treatment of natural gas
45
Table (III-1): Some gas producers in the world (2010-2013)
Producing countries Production Mm³ Share of world total (%)
Russia
United States
Canada
UK
Norway
Iran
Netherlands
Indonesia
Saudi Arabia
669,700
681,400
143,100
92 ,045
114,700
162,600
80,780
77,305
103,200
21.8
18.0
6.5
3.2
3.1
2.9
2.7
2.7
2.4
Other 1049,801 36.5
Total 3174,631 100 .0
For now, only about 15% of world gas output is subject to international trade, with three-
quarters through pipelines and the rest in the form of liquefied gas.
Russia accounts for 22% of global output, 90% of Russia’s production come from western
Siberian fields: Urengoy is the main, largest deposit.
In the world, with 10,000 billion of reserves and 35% of Russian production; other:
Yamburg (5000 billion , 28% of production), Medveje (11% of production) and Orenburg
(5% of production).
The decline in European stocks led to a production slowdown that should fall from its
current level of 310 G to 260 G by 2020. By then, the gas needs of member countries of
Chapter III Treatment of natural gas
46
OECD Europe pass 690 G , which would imply a deepening European dependence à-vis
imported gas. In 2030, domestic production no longer covers only the fifth European needs.
The faster decline than expected North Sea production has overtaken all gas operators.
New infrastructure completed in 2005 do not yet seem sufficient.
Scalded by the tension observed in March 2005, put the gas operators were exploited to
fulfill their maximum storage (useful stocks represent 25% of annual consumption in France
against only 3% in the UK). But the withdrawal of British stocks begins in early November,
with almost a month in advance. Because the decline of British fields in the North Sea also
greatly reduces the ability to "swing" (the "swing" variation is the maximum capacity of
production in the North Sea production is limited summer and winter maximized) . Thus it a
few years ago, producers could increase their production in the winter to meet seasonal
demand. But since peak production, they produce a maximum capacity (by restricting the
"swing" capacity). The decline is worse in the winter period of high demand. Also, with the
sharp drop in temperature, the double price.
As for North America, production experienced a relatively slow decline in 30 years, as
demand was inhibited by energy policy, while the number of drilling the well exploded to
compensate for reduced productivity. Now demand rises, but production of the continent is on
the brink of the cliff.
Africa is experiencing a sharp increase in production, accompanied by an increase in
exports. That is to say, it consumes little energy it has and, therefore, cannot develop.
In the future, the Middle East, CIS and offshore should represent an increasing share of
world gas production. It should be noted that the Middle East will now provide 10% of the
international market despite its reservations. This is a major difference with the oil of which
30% of production comes from this region.
For that Algeria, in 2005 we produced 143G .
In 2002, the primary production of natural gas reached 140 billion m3.
Hassi R'Mel production, which amounted to 102 billion , is contributing 73%.
Chapter III Treatment of natural gas
47
An important part of the primary gas production is used in the process of exploitation of
deposits for recycling, re-injection or consumption. The amount of gas held for sale was 81.4
billion m3.
Upgrading facilities such as natural gas liquefaction plant at Arzew and Skikda has
allowed Algeria to increase its production capacity to win today 11% gas market share
consumed in the European Union, a level that, with the prospect of doubling exports will be
close to that exported by Russia, the EU partner in the energy field.
In the coming years, the map of gas production will undergo substantial changes:
In the CIS, the Russian deposits in Eastern Siberia and on Sakhalin Island will go into
production and contribute to the balance of the Asian markets. In western Siberia, the
commissioning of new fields (Bovanenkovo, etc.) will soon become necessary to
offset the declining production of old giant fields (Urengoy, Yamburg) providers in
Europe. Moreover, given their strong gas potential, ultimately, the Central Asian
countries (Kazakhstan, Azerbaijan) will play a major role on the international market,
either through direct export or through the Russian gas network.
The development of US reserves of Alaska is a growing contribution of
unconventional gas to local gas production.
The emergence of new major producing countries in Latin America (Bolivia, Peru,
and Brazil) will offset the slowdown of the Argentine production.
The gas fields into production partner, to liquefaction (Angola, Nigeria), contributes to
progressively restrict the volumes of gas flared and improves the rate of recovery.
A major portion of the gas expansion will be based on a single super giant
accumulation of non-associated gas, operated by two countries, Qatar (North Field)
and Iran (South Pars), whose proven reserves are 21% of the world total. [2]
Chapter III Treatment of natural gas
48
III.1.5. Consumption of Natural Gas in the World:
Natural gas first appears as the source of energy most suited to meet the expectations of
the consumer countries, and most of them favor its use wherever it can replace oil.
In nearly 40 years, its share of the coverage of world primary energy demand jumped
15.9% to 23%, while that of oil down 43.6% to 35%. In some countries such as Russia and
Argentina, the use of blue or even exceeded that of black gold.
Yet the repeated credo since the first oil shock of 1973, in which the gas would be safer,
suffered a serious contradiction in January 2006 (when the gas crisis between Russia and
Ukraine); the nations that have the most resources to the now using political and diplomatic
purposes.
The twin oil energy is becoming an important means and continuity of supply is a concern,
especially as proved reserves are concentrated in three countries: Russia, Iran and Qatar who
hold two-thirds, the sixteen others, including Algeria share 1-5% of these reserves.
Today's conflicts are less about the control of the current market and on the future because
natural gas will remain plentiful when oil will run out.
III.1.6. The Gas in Algeria:
Algeria is ranked fourth in terms of proven reserves with almost 4.6 trillion cubic meters in
addition to about 1,000 billion m³ considered probable and possible reserves.
It also: second African producer after Nigeria with an annual output of nearly 152 billion
cubic meters, the third largest exporter of natural gas with a capacity to export 65 billion
cubic meters, and holds second place in the export of LPG.
Other gas is transported by pipeline to Italy, Spain, Portugal, Tunisia and Slovenia, while
the LNG transport it in a liquid state to France, Spain, the US, Turkey Belgium, Italy, Greece
and South Korea. We cover 60% of Spanish needs, 36% of Italian needs and not less than
10% of total gas demand across Europe, and this tells us (with the condensate, produced 16
MT / year and LPG ) over 60% of foreign exchange earnings.
Chapter III Treatment of natural gas
49
Do not forget the two gas pipeline project: MEDGAZ to Spain and GALSI to Italy, which
should have initial capacity of 8 billion cubic meters each. (Figure 3)
The Algeria, a pioneer in the field of gas liquefaction, is involved in projects in Peru,
Venezuela, Niger, Libya, Italy, Yemen, South Africa and Mauritania.
Finally, our country has a powerful instrument that black gold to good use is that gas
pipelines will transport not only more gas to please our customers, but also and above all
"ideas" [3]
Figure (III-4): The Algerian gas export routes.
III.1.7. Outlook:
Despite the persistently high price outlook, economic growth rate coupled with obligations
to respect national Kyoto commitments, continue to offer the new blue gold bright prospects
for development.
Thus, world gas demand is expected to grow at a rate of about 2% per year by 2020 against
1.4% for oil and coal. At this rate, the gas will lift dice 2015-2020 as the second source of
Chapter III Treatment of natural gas
50
energy instead of coal. The International Energy Agency expects a doubling of consumption
by 2030, which will represent nearly 24.2% of world primary energy demand.
LNG trade could represent 38% of world trade in 2020.
This growth will be moderate in developed countries, which continue to invest in
improving the efficiency of energy uses. On the contrary, a significant increase is expected in
the newly industrialized countries and developing countries, particularly in Asia and Africa
due to population growth and the implementation of large energy-consuming activities,
localized today in developed countries.
The North American and European markets could continue to grow at a rate of 1.7% per
annum and 2.2% per year respectively.
In the US, improvements in the operation of equipment and tax credits on solar
technologies and micro turbines to reduce energy consumption in the home will have an
impact on the use of gas in this sector. Thus, the gas demand would improve slightly in the
residential / tertiary sector.
Moreover, the gas price increase could also slow growth in the electricity sector, in favor
of new coal plants, the adopted measures also include the commissioning of new nuclear
capacity by 2030.
In non-OECD Asia and the Middle East growing gas demand could grow at a rate of about
3.5% by 2020.
Asia (India, Indonesia ...) fertilizer production is expected to require increasing volumes of
gas both as a fuel and as a feedstock for the production of urea and ammonia.
In the Middle East, natural gas is increasingly used in seawater desalination plants and in
general throughout the industry (Figure III-4).
The Tunisian and Moroccan governments are considering increasing the share of natural
gas in the national energy balance of 8% in 2006 to 24% in 2020 respectively for the first and
23% in 2020 for the second.
Chapter III Treatment of natural gas
51
We must talk about the African project called Trans African gas pipeline, the former Nigal
project, which runs from Nigeria, via Algeria probably join the great Hassi R'Mel deposit to
go to Europe. This pipeline has structuring economic effects, will try to supply neighboring
countries such as Mali, Niger, with suspenders, although consumption in these countries is
still low. This gas comes from gas flaring in Nigeria, and will thus reduce flaring and
contribute to environmental protection. The volume is between 15 and 20 billion cubic
meters.
As for Algeria, it set the goal of exporting 85 billion of gas per year by 2010 and 100
to 120 billion in 2020, as there are in reinjection gas consumption needs and local, so
there will be a production of 117 billion cubic meters in 2010 and 2020 to 172 billion cubic
meters.
Although some say the lack of realism of a gas market similar to that of the medium or
short term oil, because of the lower energy efficiency and transportation cost, saying only the
GTL option, if it is developed large scale, in more favorable economic conditions could
perhaps accelerate the process, they can completely disabuse specialists who predict that the
peak of world production of natural gas will occur in 2030 or about 20 years after that of oil,
which is in the ideal transitional fossil energy should continue to play a key role in the energy
mix of tomorrow.
In conclusion, we say that natural gas today is not about oil (having forty years in
advance), and like oil once these perspectives lot of hope but also include a number of risks.
The blind optimism of some commentators deserves to be tempered because natural gas is
certainly not a magic potion that by its own virtues will solve all difficulties. [1]
Chapter III Treatment of natural gas
52
Figure (III-5): Regional demand outlook.
III.1.8. Characteristics of Natural Gas:
III.1.8.1. Density:
The density of a gas is the ratio of its density to that of air under the conditions determined
temperature and pressure. It can also be obtained from the molecular weight that can be
defined by its chemical composition using the following relationship:
Gas density = molecular weight / 28.966
III.1.8.2. Calorific value:
It represents the quantity of heat released during the combustion of a unit volume of gas
measured under reference conditions. It is expressed by [Joules / m³].
There are two types of heating value:
Chapter III Treatment of natural gas
53
Superior calorific value (SCV): corresponding to the heat when all the combustion
products (hydrogen or hydrogen products) are brought back to ambient temperature,
the water formed being in the liquid state.
Inferior calorific value (ICV):
Corresponding to combustion in which the water remains in the vapor state. ICV differs from
the SCV of a quantity of heat which equals the latent heat of vaporization of water.
III.1.8.3. Chemical composition:
It is used for the vaporization of study. It is also used to calculate some of the properties of
the gas in terms of pressure and temperature (compressibility, density) and to define the
conditions of his treatment during the exploration (extraction liquid products).
III.1.9. The different types of Natural Gas:
Depending on the composition and regional disparity, generally there are three types of
natural gas:
1- The non-associated gas, which is not in contact with the oil.
2- The associated gas "coverage" (gas-cap gas) that overcomes the oil phase in the tank.
3- The associated gas dissolved in oil in reservoir conditions.
In addition, dry gas is a gas which does not contain readily condensable products at the
temperature and ambient pressure (that is to say it consists of methane, ethane, and some non-
condensable impurities: carbon dioxide, nitrogen, etc. ...).
In fact, no gas is dry, properly speaking; however, it is customary to apply this definition
to the gas, the condensable fraction is low.
Natural gas is said when wet, cooled to room temperature, it provides a liquid phase.
A natural gas condensate is said when the composition of hydrocarbons contained therein is
such that an isothermal expansion produces a liquid phase.
Chapter III Treatment of natural gas
54
III.1.10. Utilization:
In half a century, the gas expansion was marked reversal of trends, resource scarcity fears
that have led to the adoption of energy policy measures aimed to reserve natural gas for noble
purpose (European Directive prohibiting the use of natural gas in power plants) is the best
example.
Then the old relative of oil, which has a priori no captive market, quickly gained acclaim
thanks to a great flexibility of use compared to competing fuels, this technical superiority is
particularly noticeable in the field of electricity generation: he assured 20% of electricity
worldwide in 2006, and this share is increasing (new plants combined cycle should absorb
half the world growth of natural gas) (See Figure III-6).
In particular, 30% of gas consumption is for the residential / tertiary sector (particularly for
heating, hot water and cooking).
The new blue gold is also the raw material for much of the chemical and petrochemical
industry, almost all of the production of hydrogen, methanol and ammonia based products for
fertilizer industries , plastic resins, solvents and petroleum refining (for additives). However,
this use is recessed with 4% of the product gas compared to the industry which absorbs 25%.
Finally, a few years after the LPG, compressed natural gas bottles used as fuel for vehicles
(NGV), more than a million vehicles drive with the world, particularly in Argentina and Italy.
Note also that the synthetic diesel, which resembles to misunderstand diesel can be
produced from natural gas; the chemical conversion of gas into liquid fuel (GTL / gas to
liquid), could be a new opportunity and an attractive alternative offering a high quality diesel
fuel (no sulfur and aromatics, cetane very high) that can be directly used without adaptation of
the engine. However, its development is difficult, still handicapped by low energy efficiency
compared to petroleum products (55-60%), high costs and high emissions of carbon dioxide
linked to production. [2]
Chapter III Treatment of natural gas
55
Figure (III-6): Breakdown of the uses of gas in 2004 and 2020.
III.1.11. Processing of Natural Gas:
Gas treatment is to separate at least partly some of the components present at the outlet of
the well (such as water, acid gases and heavy hydrocarbons), to bring the product to transport
specifications or commercial specifications.
This generally involves a succession of steps aimed at:
Purification and Dehydration:
It may be necessary to remove at least partially:
Water which leads to hydrate formation.
Mercury is extremely dangerous to humans and in some cases corrosive to equipment.
The carbon dioxide (corrosive and thermal zero value).
Hydrogen sulphide (toxic and corrosive).
Nitrogen (thermal zero value).
Fractionation of hydrocarbons: It is done mostly by temperature reduction, and leads
to obtaining the following liquids cuts:
a- Gasoline or condensation: light gasoline (C5+ fraction).
b- The LPG fraction (LPG): includes propane and butane.
The mixture of gasoline and LPG (also containing C2) is called "liquefied natural gas" (LNG).
Chapter III Treatment of natural gas
56
In addition to the "dry gas" part, which can be liquefied at (-160 ° C) in specific facilities
to be transported as liquefied natural gas (LNG).
The condensate and LPG have such market value as some deposits are mined only for
them; the gas is fed back either totally or partially progressively into the reservoir to increase
the pressure and recover the final more LPG and condensate.
III.1.12. Specification of the treated gas:
In the case of pipeline transport:
The specifications aim in this case to avoid the formation of a liquid phase (water or
hydrogen), the locking of the conduit by hydrates and excessive corrosion. Is imposed for this
maximum value to dew points. The value of the hydrocarbon dew point depends on the
conditions of transport and can for example be set at 0 ° C, to avoid formation of liquid
phases by retrograde condensation.
In the case of a commercial gas:
The specifications are more stringent and also include a range within which must be calorific.
Typical specifications for commercial gas are shown in the following table:
Table (III-2): Specifications of commercial gas.
Value Unit
Dew Point < -6 °C
Water content < 150 ppm vol
content C5+ < 0.5 % mol
Superior Calorific power SCP 39100- 39500 KJ/m³ (n)
Chapter III Treatment of natural gas
57
The H2S content that may contain processed gas is generally very low and usually varies
between 2 and 20 mg / m³ (st). A common specification, in Anglo-Saxon unit, is 0.25 grains /
100 Seft either 6 mg / m³ (st) or about 4 ppm.
When natural gas is liquefied, pretreatment should prevent any risk of crystallization in the
heat exchangers of the liquefaction unit. A split between methane and heavier hydrocarbons is
generally operated during liquefaction.
Therefore, the gas obtained after arriving at the LNG regasification receiving terminal can
in principle be directly sent into the distribution network. If the gas undergoes a
transformation by chemical conversion, the pretreatment depends on the nature of the
conversion process used. The use of catalysts, in particular, imposes specifications that are
frequently very severe.
III.2. LIQUEFIED PETROLEUM GAS (LPG):
LPG is a mixture of hydrocarbons having a low molecular weight with three or four carbon
atoms, that is to say: propane, propylene, n-butane, isobutane, and butenes, in varying
proportions. The butane and propane are the main components.
The production of this fuel is derived from crude oil processing in refineries and separation
(outgassing) of natural gas (methane ethane). Liquefied petroleum gas may also contain small
amounts of methane, ethylene, pentane and pentenes and exceptionally hydrocarbons such as
butadiene, acetylene and methyl acetylene. [7]
These hydrocarbons are present only as byproducts of the production of olefins
petrochemical use (steam cracking). Apart from hydrocarbons is also find some sulfur
compounds (mercaptans and alkyl sulfides) in extremely small quantities, but have some
significance regarding the corrosiveness of the product.
LPG is easily liquefying gas at ambient temperature under low pressure (4-18 atmospheres):
this allows storage and transportation easier for non-condensable gases such as methane,
ethane and ethylene which require very high pressures to be liquefied at ambient temperature.
Chapter III Treatment of natural gas
58
III.2.1. Liquefied Petroleum Gas in the world:
World production in 2004 reached 213 million tons. World production of LPG is growing
at 5% per year.
60% of world production comes from natural gas, 40% of the refining of crude oil
(1Tonnes of petroleum Gas gives 20 to 30 Kg LPG).
In that year, the LPG demand for residential and commercial heating in Asia exceeded that
of North American residential and commercial combined chemical sectors.
Consumption in the EU in 2004 is 16.5 million tones.
In the United States, where a long tradition of use exists, production and consumption are
balanced.
In the Middle East, production of LPG has grown significantly in the late 70s when the
increase of energy prices made attractive recovery of propane and butane. Previously, these
products were burnt with associated gas. This region is currently the main source of export of
LPG in the world.
Algeria and North Africa, where LPG is mostly recovered from the natural gas
liquefaction units, refinery production ensures the complement, propane and butane are
recovered at the atmospheric distillation of crude oil and by cracking of heavy molecules in
most processing units and conversion.
Propane and commercial butane are not pure compounds but mixtures, complete separation of
molecules is also expensive useless because most uses Allow mixtures.
III.2.2. Liquefied Petroleum Gas in Algeria:
Production fell to 8.4 million m3 in 2006 against 8.6 million m
3 in 2005.
85% of production comes from gas units fields (Hassi R'Mel, Stah, Alrar, Tin Fouyé
Tabenkort, Hamra, Rhoude Nouss, Hassi Messaoud, Berkaoui and Oued Noumer). Total
production of LPG is transported via pipe LR1 (998 Km), itself connected to central storage
and transfer (CSTF) located at Hassi R'Mel. There they got rid of any traces of water before
being shipped to the SP4 pumping station and then transported to the complex separation of
Arzew and Béthioua. The rest of the production comes from LNG units in Skikda, Bethioua
and refineries. Our country exports 8.04 million tons of these materials in 2003, supplying 23
countries.
Chapter III Treatment of natural gas
59
In the domestic market, volumes sold totaled 1.85 million tones; the growth rate during
2005 on the LPG market is 1.5%.
The national consumption of LPG (90% essentially of butane) is satisfied through the
territory by routing products for the various regions by tankers, cabotage vessels and recently
by rail through the transport company energy products (TCEP).
During the last decade, the Algerian LPG industry has undergone profound changes,
particularly in terms of production, export and shipping.
III.2.3. Algerian exports of the Liquefied Petroleum Gas:
Mediterranean: 80% (France, Italy, Spain, Portugal, Morocco, Turkey, Egypt, Lebanon,
Tunisia, Syria).
USA: 14%
Latin America: 3% (Brazil, Mexico, Ecuador, Guatemala, Puerto Rico)
Asia: 2% (Korea, China, Japan, Singapore, Australia)
Northern Europe: 1% (Holland, Sweden, Belgium, Finland, England)
The gas resources development program, launched in the early 90s, is today Sonatrach benefit
of large supplies of LPG. Since the commissioning of the gas field Hamra in 1996, LPG
production has followed a steady growth. It should reach a volume of 11 million tonnes with
the commissioning of new facilities.
III.2.4. Use of the Liquefied Petroleum Gas:
The main domains of use of LPG are:
Combustible: cooking, hot water or heating, supplied by distributors in liquid form, bottled or
bulk. In some cases, customers are supplied from networks or propane air as propane or
butane as in Corsica. It is used by individuals or as industrial combustion gases.
Chapter III Treatment of natural gas
60
The use in the tertiary residential sector (cooking) is concentrated mainly in Spain, France,
Turkey and Italy. Worldwide, nearly 500 million households and one in two in the European
Union use.
in air conditioning: In air conditioners or refrigerators:
Either LPG absorbs heat from the environment to evaporate and creates a cold.
Either an engine running on LPG can drive a compressor which compresses the gas "LPG"
and relaxation absorbs heat.
As fuel: The combustion of LPG is clean enough, it produces no soot, no carbon
monoxide, unburned hydrocarbons relatively few and relatively little carbon dioxide
compared to other fuels derived from petroleum. Furthermore, the unburned hydrocarbons
from the combustion of LPG are short carbon chains, and therefore less toxic than their
counterparts from gasoline, diesel, or oil.
It is a fuel that preserves vehicle performance and even reduces engine wear.
LPG represents 60% near the park "essence" in the Netherlands, over 30% in Italy, 40 to
60% in the US and Canada.
The use of LPG in Algeria remains very low, with only 120,000 vehicles were converted to
liquefied petroleum gas.
Experts explain the wrong that Algeria is producing LPG / C, a transport sector that
depends 96% liquid hydrocarbons. "Transport consumes today nearly 2/3 of final
consumption of petroleum products, while consumption of LPG / C is only a small part."
Forecasters say that if Algeria continues to use more diesel and gasoline at the expense of
LPG, it will eventually be forced to import diesel to meet increasingly growing market.
In Europe, sales as fuel (50% butane - propane 50%) are concentrated to 90% in Italy (1
million units) and the Netherlands (500,000 vehicles or 8% of the park). In France, in 2004,
180,000 light vehicles and 135 buses use LPG as fuel with a consumption of 151 000 T.
In Japan, Tokyo 250,000 taxis using LPG.
Chapter III Treatment of natural gas
61
Table (III-3): Uses of Liquefied Petroleum Gas in France and worldwide
World France World France
Residential and
commercial 50 % 61 % Fuel 6 % 9 %
Chemistry and Refining 35 % 13 %
Agriculture 2 % 17 %
other industries 13 %
LPG in the industrial sector, other than chemistry is important in Germany (25% of use)
because the LPG combustion flame can be in direct contact with the products, food
processing, glass, ceramics, metallurgy ... The agricultural sector is important in France, in the
heating of buildings poultry farms and pigs, greenhouses, drying crops ... propane is also used
as fuel for forklifts: 110000 Tonnes in France in 2004.
LPG is also incidentally used in lighters (butane).
In the petrochemical domain:
Domain where Algeria is determined to catch up due to any investment decision which
was spread for good numbers of years. At the moment, it is the most targeted sector projects
and reforms.
Liquefied petroleum gas is used as raw material for the production of ethylene, propylene,
ammonia, and MTBE.
18% of LPG is consumed as a feedstock for the petrochemical industry, mainly for the steam
cracking for the production of olefinic and aromatic bases. However, there are other
petrochemical uses of LPG.
Propane in the manufacture of petrochemical flagship product:
Ethylene;
Propylene by dehydration.
Ammonia by conventional reforming.
Acrylonitrile by Ammoxidation.
Chapter III Treatment of natural gas
62
While butane participates in the development of:
MTBE (used as a booster of essences substitution in the PTE) by dehydrogenation.
Butadiene, by dehydrogenation.
Maleic Anhydride.
Propylene oxide by cooxidation.
III.2.5. Characteristics of Liquefied Petroleum Gas:
The physicochemical characteristics of LPG (distillation curve, vapor pressure, density,
calorific efficiency in engines, etc.) depend on their content of various hydrocarbons (see
Table 5).
Commercial products are very different from each other. In addition, their vapor pressure,
their density and their antiknock properties are very sensitive to changes in ambient
temperature.
Steam –Tension
At 20 ° C, LPG has a vapor pressure:
2 bars for butane.
8 bars for propane.
Density:
For propane: 0.51; for butane: 0.58.
Refined LPG is normally almost odorless and highly flammable, given their volatility.
They can give, upon contact with air, explosive mixtures. To better recognize or detect any
leaks, given a particular odor by appropriate substances (mercaptans).
LPG generally contains no lead or benzene and very little sulfur (<0.005% by weight),
which provides for the use of fuel a great environmental benefit. At atmospheric pressure, it
liquefies at a temperature of about -30 ° C.
Chapter III Treatment of natural gas
63
The expansion of LPG is about 0.25% per degree Celsius, it must be taken into account
during storage (spheres should never be completely filled).
LPG is not corrosive to steel but usually is for aluminum, copper and its alloys. They have
no lubricating property, which must be taken into account when designing equipment for LPG
(pumps and compressors).
GPL with mild anesthetic potency if inhaled long and can cause headaches and stomach
aches.
LPG, when spreads in its liquid form, out of a pressurized container, evaporates generating
cold: in contact with the skin, it causes burns characteristics called "cold burns".
III.2.6. Liquefied Petroleum Gas specifications Gassi Touil (CPF):
This fraction must meet the specifications:
Content C2- ≤ 3% molar.
Content C5+≤ 0.4% molar.
Chapter III Treatment of natural gas
64
Table (III-4): Characteristics of Liquefied Petroleum Gas components
Characteristics of LPG components
methane ethylene ethane propylene propane isobutane butylene butane
Chemical formula CH4 C2H4 C2H6 C3H6 C3H8 C4H10 C4H8 C4H10
vapor pressure at 10 °
C (kg / cm2) 370 45 32 7,7 6,2 1,3 1,7 1,5
boiling point at 760
mm Hg (° C) -161,5 -103,7 -88,5 - 47,7 - 42 - 11,7 - 6,2 - 0,5
Specific weight Kg /
Liter 0,3 - 0,37 0,52 0,51 0,56 0,6 0,58
liters of gas obtained
from one liter of
liquid
443 333,7 294,3 283,5 272,7 229,3 252,9 237,8
specific weight of the
gas at 15 ° C 760
mmHg Kg/ m3
0,677 1,18 1,27 1,77 1,86 2,45 2,37 2,45
Gross calorific
(Kcal/Kg) 13288 12028 12417 11700 11980 11828 11589 11586
Kg combustion air
per kg of gas 17,4 15 16,2 15 15,8 15,6 15 15,6
Octane number 120 76 99 83 96 97 84 89
Chapter III Treatment of natural gas
65
III.3. THE CONDENSATE:
III.3.1. Generality:
The condensate, also said « more pentane » or « C5+ » or "well of natural gas liquids"
means the light fraction from pentane (C5 H12) to decane or more. Unlike the crude
condensate is not liquid in the deposits, but gas (due to the temperature), and condenses when
cooled by expansion to the wellhead.
This is an important contribution to world supplies, order of 6Mbep / J, and it comes to
more high quality liquids (light and low in sulfur).
It is rare that the amounts concerning the condensate are given explicitly; they are almost
always included in the crude oil, except for OPEC countries, as they are excluded from the
quotas. It also happens that the condensate produced by the deposits mined for crude oil is
counted with it, but as that produced by the gas fields to be counted separately (this is the case
in the USA for example). [1]
III.3.2. Properties of the Condensate:
Aspect:
It is a colorless liquid with an odor of gasoline.
Specific weight:
It is between 0.7 to 0.8 (N/ )
Flash point:
It must be less than - 40 ° C.
Flammable Limits:
Flammable, since it has a point below zero flash, its flammability limits are approximately:
1.4 to 7.6 vol (in air).
Vapor density:
Chapter III Treatment of natural gas
66
Vapors are heavier than 3 to 4 times higher in terms of density relative to air.
Explosive and Flammable:
The Condensate is highly inflammable and evaporable fluid at normal temperature and
pressure, because it is not electrically conductive, presents a danger of fire or explosion due to
electrostatic discharge announced by casting, filtration, fall, spray, etc..... We must be careful
because the vapors of condensate are an explosive gas mixture is spread on the ground
because of its higher density than that of air.
Physiological toxicity:
Condensate vapors are toxic; when a person exposes himself, the first symptom noticed is
eye irritation monitoring neuropathy symptoms (dizziness).
Victim may eventually start yelling, singing, laughing stupidly, and end up having trouble
walking. When the concentration of vapor condensate is in the range of 0.025% to 0.05% by
volume in the air, they cannot cause serious harm, even after hours of inhalation.
Caution:
To avoid poisoning, one must achieve a proper ventilation of work and maintain
concentration of vapor condensate less than 300ppm.
Utilisation:
This fraction is especially valued in the domain of refining:
Oil-rich paraffinic and naphthenic ( - ), the condensate has a good potential to olefins.
It is used for fuel production, including species, their cost is lower than gasoline produced
from crude oil since the separation and processing of the condensate is less expensive and its
chemical composition rich in light elements.
It is also used for isomerization to obtain gasoline-isomerizate, transforming normal
paraffins iso-paraffins high octane and is also used in catalytic reforming.
Chapter III Treatment of natural gas
67
Manufacturers today are learning to build on two fundamental pillars of sustainable
development: the human factor and respect for the environment.
From this idea was born the new policy that makes corporate magazines:
HSE policy: Health Security Environment.
CHAPTER IV
Thermodynamic
Study
Chapter IV Thermodynamic study
68
IV. INTRODUCTION
As our work is based on thermodynamic considerations involving quantities such as
entropy, we found it useful to recall the general principles of thermodynamics and establish
quantitative forms expressing them.
According to a program called Thermoptim we using it to calculate the Enthalpy and
Entropy with the parameters (Temperature and molar fraction, pressure).
IV.1. DEFINITIONS
Enthalpy: a thermodynamic quantity equivalent to the total heat content of a system.
It is equal to the internal energy of the system plus the product of pressure and
volume.
H = U + PV ∆H = ∆(U + PV) =
Entropy: a thermodynamic quantity representing the unavailability of a system's
thermal energy for conversion into mechanical work, often interpreted as the degree of
disorder or randomness in the system.[4]
S =
∆S =
IV.2. CONCEPT ON THE RELAXATION:
Relaxation or expansion is the process that produces the cold in an LPG recovery plant.
The expansion may be performed in two ways:
Through a valve (also called Joule -Thomson).
By a machine (Turbo-Expander). [1]
IV.3. THERMODYNAMICS STUDY:
IV.3.1. First law of Thermodynamics:
The first law of thermodynamics to express the conservation of energy. It is written to a
closed system for the mass unit, neglecting the changes in kinetic and potential energy of the
flowing fluid:
∆U = U2 – U1 = Q + W
With:
∆U: Internal energy change.
Chapter IV Thermodynamic study
69
Q: Heat quantity exchanged.
W: Work received or provided by the system.
IV.4. RELAXING WITH PRODUCTION WORK (TURBO-EXPANDER) G11-
KH-32-201:
Another type of relaxation may be performed in an expansion turbine; the energy of the
compressed gas is converted into work.
The expansion is thermally insulated, so the evolution occurs and there is an adiabatic
cooling of the gas.
In the real process, evolution is obviously irreversible due to friction force in the turbine.
However, in the idealized process, it is assumed that evolution is reversible.[4]
IV.5. THERMODYNAMIC ANALYSIS OF TURBO-EXPANER
PERFORMANCE:
The formulas and theoretical concepts set out below are those strictly required for
calculations of the cycles and turbo-expander performance.
IV.5.1. First law of Thermodynamics:
Applied to the turbo-expander, it is written between the inlet (1) and the outlet (2) of the
fluid:
......................................(1)
In adiabatic flow 0Q , this relationship becomes:
…..........................................(2)
For Turbine:
…………………………..(3)
IV.5.2. The specific heat of a gas mixture:
∑ ………………………………(4)
Chapter IV Thermodynamic study
70
IV.5.3. The molecular weight of a gas mixture:
[ ] ∑ ………………………………………..(5)
IV.5.4. The isentropic exponent:
………………………………………………… (6)
IV.5.5. The specific gas constant:
: Constant universal of ideal gas =8,314[kj/mol.k].
: Constant real gas:
[ ]
……………………………..(7)
IV.5.6. Compressibility factor Z:
The calculation of compressibility factor Z is carried out using the following parameters:
, , , and such as: k
: The mole fraction of each component of the mixture.
: The critical temperature of each component of the mixture.
: The pseudo-critical temperature of each component of the mixture.
: The critical pressure of each component in the mixture.
: The pseudo-critical pressure of each component in the mixture.
The pseudo-critical temperature of this mixture is given by the following equation:
∑ ∑ …………………………..(8)
The pseudo-critical pressure of our mixture is given by the following equation:
∑ ∑ ………………………………………(9)
Chapter IV Thermodynamic study
71
The reduced temperature is:
….........................................................(10)
The reduced pressure is:
…………………………………………. (11)
With:
: Operating temperature °C
: Operating pressure.
: Reduced temperature.
: Reduced pressure.
Correlation of S.Robertson:
[ ]…………..................(12)
………….................. (12.a)
…………........................... (12.b)
………….................... (12.c)
………….................... (12.d)
Chapter IV Thermodynamic study
72
IV.6. WORKS RELAXATION:
Figure (IV-1): Diagram H-S side Expander.
This has as consequences:
An outlet temperature higher than due to the heating of gas by friction.
A drop in enthalpy lower than In summary:
………………………………(13)
………………………………..(14)
IV.7. METHOD OF CALCULATING THE EFFICIENCY OF THE
TURBINE:
It is interesting to measure the performance of a machine to compare the real development
of gas with the following characteristics:
QF = 0: no degradation of energy by friction (reversibility of energy transformations).
QF = 0: adiabatic engine: no heat exchange with the outside (the machine is
insulated).
Chapter IV Thermodynamic study
73
The Efficiency of the adiabatic machine is finally the ratio of the actual work and the
isentropic work:
(
) ………………………………(15)
(
) ………………………………(16)
Or:
………………………………(17)
………………………………(18)
IV.7.1. Calculation of enthalpy and entropy at the entrance of the expander
H1 and S1:
In this section, the calculation of Enthalpy and Entropy is based on temperature T1 and
pressure P1.
Using the equilibrium diagrams of each component value is taken of Hi and Si to
corresponding state.
T1 Equilibrium diagram T2
P1 P2
The total enthalpy in point (1) (the inlet of the expander) equal to the sum of the enthalpy
changes in the process.
∑ ………………………………(19)
Chapter IV Thermodynamic study
74
Where:
: The mole fraction of each component in the gas mixture.
In the same way: S1
The total entropy point (1) (the inlet of the expander) is the sum of the enthalpies.
∑ ………………………………(20)
IV.7.2. Calculating enthalpy, entropy discharge the output
expander :
In the case of a turbo-expander, the expansion in the turbine (expander) is associated with a
gas change of state and composition. After the discharge at a very low temperature; there is a
mixture biphasic (liquid - vapor); so the enthalpy at the outlet of the expander is the sum of
vapor and liquid enthalpies. [4]
………………………………(21)
Similarly way to entropy:
………………………………(22)
Th eref o re :
: Evaporation rate (represents the percentage of steam in the outlet of the machine).
: Enthalpy of the gas phase at the outlet.
: Entropy of the gas phase at the outlet.
: Enthalpy of the liquid phase at the outlet.
: Entropy of the liquid phase at the outlet.
IV.7.3. The actual work of relaxation:
…………………………………………. (23)
Chapter IV Thermodynamic study
75
IV.7.3.1. Calculation in Expander side:
Inlet side:
elements Yi Mi ∑ Yi, Mi ∑Yi,
N2 0,0225 28,013 0,6302 1,0391 0,2337
CO2 0,0090 44,01 0,3960 0 0
C1 0,8630 16,043 13,8451 2,1256 1,8343
C2 0,0730 30,07 2,1951 1,4491 0,1057
C3 0,0222 44,097 0,9789 1,4197 0,0315
C4 0,0036 58,124 0,0209 1,3983 0,0050
C5 0,0012 72,151 0,0865 1,4320 0,0017
∑ 0,99 / 18,15 / 2.2119
elements Yi Pc ∑Yi, Pc ∑Yi,
N2 0,0225 33,99 0,7647 126,1 2,8373
CO2 0,0090 73,82 0,6644 304,19 2,7377
C1 0,8630 46,04 39,7325 190,5 164,4015
C2 0,0730 48,8 3,5624 305,4 22,2942
C3 0,0222 42,49 0,9433 369,82 8,2100
C4 0,0036 36,48 0,1313 425,16 1,5310
C5 0,0012 33,81 0,0406 460,39 0,5525
∑ 0,99 / 45,8392 202,5642
Kj/kg °K
Kj/kg °K
– = r 2.2119 - 0, 4580= 1, 75
Chapter IV Thermodynamic study
76
1.2639
Pseudo-critical Temperature K.
Pseudo-critical pressure bars.
IV.7.3.2. Calculation of
X A B C
1,3089 1,1798 1,1094 0,1354 5,9219 0,8756
0,2032
IV.7.3.3. Calculation of :
X A B C
0,6111 0,1259 7.3191 0,3480
0,04569
Chapter IV Thermodynamic study
77
IV.7.3.4. Calculating enthalpy, entropy inlet turbo-expander:
P1 = 65 bar
T 1 = -20°C
COMPOSITION Yi Hi ∑ Yi, Hi Si ∑ Yi, Si
N2 0.0225 496,15 11,1634 3,1 0,0698
CO2 0.0090 681,08 6,1297 4 0,0360
C1 0.8630 946,15 816,5275 5,07 4,3754
C2 0.0730 896,15 63,4480 3,86 0,2818
C3 0.0222 838,7 18,6191 3,4 0,0755
C4 0.0036 725,92 2,1331 2,6 0,0094
C5 0.0012 350 0,4200 2,68 0,0032
∑ / / 918,4408 / 4,8511
KJ/kg
KJ/Kg °K
IV.7.3.5. Enthalpy calculations, entropy output expander gas phase:
P2 = 23 bar
. T2 = -61 °C
COMPOSITION Yi Hi ∑ Yi, Hi Si ∑ Yi, Si
N2 0,0043 467,3 2,0093 3,11 0,0133
CO2 0,0409 282,19 11,5415 0,91 0,0372
C1 0,8938 868,79 776,5245 4,89 4,3706
C2 0,0548 864,15 47,3554 3,76 0,2060
C3 0,0068 794,35 5,4015 3,33 0,0226
C4 0,0002 273,07 0,0546 1,1 0,0002
C5 0 288,79 0 1,18 0
∑ / / 837,4853 / 4,6499
837,4853KJ/kg
KJ/Kg°K
Chapter IV Thermodynamic study
78
IV.7.3.6. Enthalpy, entropy calculations output expander liquid phase:
P2 = 23 bar
T2 = -61 °C
COMPOSITION Yi Hi ∑ Yi, Hi Si ∑ Yi, Si
N2 0,0005 467,3 0,2336 3,11 0,0015
CO2 0,0123 282,19 3,4709 0,91 0,0111
C1 0,434 868,79 377,0548 4,89 2,1222
C2 0,2732 376,92 102,9745 2 0,5464
C3 0,1618 342,74 55,4553 1,77 0,2863
C4 0,0207 273,07 5,6525 1,1 0,0227
C5 0,0049 288,79 1,4150 1,18 0,0057
∑ / / 546,2566 / 2,9959
546,2566KJ/kg
2,9959KJ/Kg °K
813, 8115KJ/Kg
KJ/Kg °K
IV.7.3.7. Actual calculation of enthalpy, entropy output expander gas phase:
P2=29,46 bar
T2actual= -60 °C
Chapter IV Thermodynamic study
79
COMPOSITION Yi Hi ∑ Yi, Hi Si ∑ Yi, Si
N2 0,0046 473,07 2,17 3,14 0,014
CO2 0,0414 290,41 12,02 0,95 0,040
C1 0,8882 898,11 797,70 4,89 4,343
C2 0,0588 852,83 50,14 3,84 0,225
C3 0,0062 798,38 4,95 3,35 0,002
C4 0,0002 284,61 0,05 1,15 0,00023
C5 0 349,73 0 1,26 0
∑ / / 867,03 4,6242
867,03KJ/kg
4,6242KJ/Kg. °K
IV.7.3.8. Actual calculation of enthalpy, entropy output expander Liquid Phase:
P2=29,46 bar
T2actual= -60 °C
COMPOSITION Yi Hi ∑ Yi, Hi Si ∑ Yi, Si
N2 0,0005 473,07 0,23 3,14 0,001
CO2 0,0785 290,41 22,79 0,95 0,074
C1 0,4227 898,11 379,63 4,89 2,067
C2 0,2782 384,9 107,08 2,03 0,564
C3 0,1573 354,85 55,81 1,83 0,287
C4 0,0185 284,61 52,65 1,15 0,021
C5 0,0109 394,73 4,30 1,26 0,013
∑ / / 622,49 / 3,027
622,49KJ/Kg
Chapter IV Thermodynamic study
80
3,027KJ/Kg °K
849, 1052KJ/Kg
4,507KJ/Kg. °K
Actual enthalpy is:
69,3356KJ/Kg
The enthalpy isentropic is:
KJ/Kg
Performance computing expander:
.100
Entropy is:
Chapter IV Thermodynamic study
81
0, 3368KJ/Kg°K
So the turbine work:
KJ/Kg
Actual work:
KJ/Kg
IV.8. INTERPRETATION OF RESULTS:
The adiabatic efficiency of turbine expansion is low from the mean value
and this shows that the machine operates in a value of the lower yield than the
manufacturer.
Changing parameters of pressure, temperature and the condensable fraction affect the
performance of the machine.
Conclusion
82
Conclusion
This work at the Central Production Facilities helped us to complete and consolidate our
theoretical knowledge with practical findings and manipulation on ground.
The obtained results confirm that the variation of the raw gas composition and the inlet pressure
are directly affecting the operating parameters.
Even this raw gas variation composition and the pressure affect the efficiency of the turbine
which the designer determine that the efficiency of the Expander is 85% meanwhile the real
efficiency we have calculated was 66,27 %.
Despite of this value is considered low when we compare it with the designer value, but the
Turbo-expander still one of the high technology used in industry.
The overall conclusion that emerges from this study shows that the Turbo-Expander is a vital
organ, which must give more attention to avoid stops that lead to a loss in appreciable quantities of
Liquefied Petroleum Gas and condensate; and therefore proposes the following recommendations:
Minimize disruptions Turbo-Expander except for maintenance reasons.
Do further study to calculate the parameters optimized operation of Turbo-Expander (P
& T) to enhance recovery of Liquefied Petroleum Gas and Condensate.
Do further study to optimize the injection of methanol at interchanges (G11-GA-32-201A
and B / GA-G11-32-202A and B) and Turbo-Expander to prevent icing.
Bibliographic
Bibliographic
[1] HADROUG, Y., "optimisation des parametres opératoires relatifs au
Turbo-Expander en vue de récupération le maximum des liquides"
Mémoire d'ingénieur, Direction Regionale de Gassi Touil, 2015.
[2] BENMESTFA, M ., " Etude Comparative d’une Détente Isenthalpique
et Isentropique et Influence sur la Récupération de GPL et Condensat"
Mémoire Fin de mise en situation professionnelle, Direction regionale de
gassi touil, 2014.
[3] GUEMGAM, ABD ELKADER., "Etude thérmodynamique sur le Turbo-
Expander au CPF", Mémoire d'ingénieur, Direction Regionale de Gassi
Touil, 2013.
[4] LAKHDARI, ABD ELATIF., " Etude Thermodynamique et Mécanique
du Turbo-Expander 01 EC 141 et Calcul du Rendement Actuel de La
Machine" Mémoire de fin de formation d’induction, 2013.
[5] MOHAMED, R M. BABAGHAYOU, M. GHOFRANE, M
ABDELMOUMEN "Etude Des Performances D'un Turbo-Expander"
Mémoire d'ingénieur, Université Saad Dhleb de Blida, 2006.
[6] BENSAHAD, ., "Présentation du nouveau projet de traitement de gaz
(CPF) à GTL", Rapport de stage, Direction Regionale de Gassi Touil,
2014.
[7] MANSOURI, ABD ELALI., " Etude mécanique d’un turbo-expander
ACMTC 727" Mémoire d'ingénieur, Direction Regionale de Gassi Touil
2014.
Abstract:
Through this work we have tried to study the performance of the Turbo-expander by using
analysis thermodynamic study of this machine, which is considered one of modern
technologies in the domain of industry, especially gas processing, because of high ability to
cooling until -61 ° C and therefore what is known as the process of Cryogenic, our study
were in an area called Central Production Facilities located in the Gassi Touil.
At last, after we calculate Enthalpy and Entropy of the components of the gas at Inlet and
Outlet of Expander by using a Thermoptim program, we were able to calculate the cost-
effectiveness of Turbo-expander, so we focused on the side Expander and corresponds result
is 66,27%.
Although the performance of the Expander is considered weak compared with what the
designer gave 85% but the Turbo-expander remains its use widely in the industrial domain.
Key words: Turbo-expander, Expander, Thermoptim, Gassi Touil, Cryogenic
:ملخص
رنك عه طشيق دساسح ذشمديىاميكيح نزي اآلنح انري ذعرثشمه Turbo-expanderمه خالل زا انعمم حانىا دساسح أداء
غايح ( قذسذ انعانيح عهى انرثشيذ إنىLPG and LNGانركىنخياخ انحذيثح في مدال انصىاعح, خاصح معاندح انغاص )
Central Productionحية ذمشزةضخ دساسةرىا فةي مىتدةح ذةذعى Cryogenicدسخةح مويةح, فيمةا يعةشـ ت ة -06
Facilities قاسي انتيم. في انري ذدع
ذخشج مىة Turbo-expanderفي األخيش, تعذما قمىا تحساب األورانثي األورشتي نمكواخ انغاص انمخرهفح انري ذذخم
ير, ندةذ زاوةد دساسةرىا مدرصةشج عهةى خاوةة ذمكىا مه حساب مشدد حي Thermoptimرنك تاسرعمال تشوامح يذعى
%66,27.زاود انىريدح انمرحصم عهيا فدط )انداوة انمخرص تانرثشيذ(, Expanderان
-Turboإال أن %85 ذعرثش ضويهح مداسوةح مةع قيمةح انمعتةاج مةه طةشـ انصةاوع Turbo-expanderتشغم أن مشدديح
expander .يثدى اسرعمان اسع في انمدال انصىاعي
انردميذانمرسع, انمرسع, ذشمتريم, قاسي انتيم, ذست :المفتاحية الكلمات