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SFR-based mobile system for heat recovery
Robert Aranowski, Aleksandra Korkosz, Konrad Smolarczyk, Joanna Mioduska, Jan Hupka
Department of Process Engineering and Chemical Technology
UBIS International Energy Conference
Vilnius, 8-10th October 2019
Incentive for the pilot
Industrial symbiosis is an important element of the circular
economy as it offers tools to make better use of existing
resources.
The industrial symbiosis - as understood at GUT - is mainly of
economic importance, nevertheless, the undoubted
environmental benefits also speak for its implementation.
Symbiosis contributes to local development and the increase
of corporate social responsibility, as well as mitigates climate
change.
Pilot installation using SFR reactorOur task in the UBIS project was, design and
construction of an installation for low-
temperature heat recovery from exhaust gases
of diesel engines.
The installation uses a new, very efficient gas-
liquid heat exchange system in the Spinning
Fluids Reactor SFR.
This heat can be used in another enterprise or in
a public facility, e.g. greenhouses and for heating
the sidewalk in the vicinity of public
transportation stops in winter.
Direct contact heat exchangers
Involve heat transfer between
hot and cold streams of two
phases in the absence of a
separating wall.
Can be classified as:
▪ Gas–liquid
▪ Immiscible liquid–liquid
▪ Solid-liquid or solid–gas
Most direct contact heat
exchangers fall under the
Gas–Liquid category.
Direct contactors for heat recovery
Disadvantages▪ The fluid streams mix, unless the streams are immiscible▪ Comparable pressure of contacting phases▪ Evaporation of the liquid, contamination of the gas phase
Advantages
▪ Lack of surfaces to corrode or foul▪ Compact size of heat exchanger per energy flux▪ Significantly extended heat transfer surface area▪ Heat transfer at much lower temperature difference between the two streams▪ Low pressure drop▪ Low capital and operating costs▪ Removal of fine particles (soot)▪ Selective removal of gaseous contaminants
Direct Contact Heat Exchangers
▪ Spray columns
▪ Baffle tray columns
▪ Sieve tray or bubble tray columns
▪ Packed columns
▪ Pipeline contactors
▪ Mechanically agitatedcontactors
▪ Spinning Fluids Reactor (SFR)
Typical mechanically
agitated towers
[Treybal, (1966)].
Schematic of a disk and donut baffle tray
column for use as a steam condenser
[Jacobs and Nadig (1987)].
Design and principle of SFR operation
▪ New efficient liquid-gas contacting system for energy recovery is offered
▪ The operating temperature for the gas phaseis up to 600C
▪ Low pressure drop for the gas phase
▪ Possibility of SFR scale-up by multiplication of units
Reactor Head
Reactor Body
Inner Porous Partition
LIQUID INLET
GAS INLET
Liquid flow in SFR Top view of the SFR interior
Bubble generation mechanism in stagnant liquid
wFF
= gNd
r ggc
p
k −= )(6
2
3
3
)(12
gN
rd
ggc
kp
−
=
Bubble generation
in stagnant liquid
Where:
rk - radius of capillary,
- surface tension,
dp - diameter of bubble,
c - density of liquid,
g - density of gas,
g - gravitational acceleration,
Ng - dimensionless centripetal acceleration
ow FFF
+=42
22
bc
o
duF
=
2
16
u
rd
c
k
b
=
4
1
32
24
=
c
kp
f
r
ud
Bubble generation in flow liquid
Where:
db, dp - diameter of bubble,
u - linear liquid velocity,
- resistance coefficient depended
from Reynolds's number,
- viscosity,
f - friction factor
Laminar flow Turbulent flow
Bubble generation mechanism in stagnant liquid
SFR inner porous tube
Gas bubbles generated in SFR
50 L
/min
Water 5 ppm MIBC
30 L
/min
70 L
/min
Wa
ter
flo
wra
te
Materials for inner porous tube or screen
∆P𝑝= ∆𝑃𝑑 + ∆𝑃𝑐
Where:
∆P𝑝 - gas phase pressure drop,
∆P𝑑 - resistance of flow through
the porous material
∆P𝑐 - resistance of gas flow
through the layer of
rotating liquid
Bubble size distribution for QW =
20 dm3/min, QG= 55 m3/h
Ab
un
dan
ce(%
)
Diameter (mm)
Bubble size distribution in SFR
Bubble size distribution for QW =
20 dm3/min, QG= 25 m3/h
Ab
un
dan
ce(%
)
Diameter (mm)Bubble size distribution for QW =
20 dm3/min, QG= 35 m3/h
Ab
un
dan
ce(%
)
Diameter (mm)
Bubble size distribution for QW =
30 dm3/min, QG= 45 m3/h
Ab
un
dan
ce(%
)
Diameter (mm)
Residence time of liquid in SFR
Porous Partition -Perforated Plate
0 20 40 60 80 100 120
0,2
0,4
0,6
0,8
1,0
Re
sid
en
ce
Tim
e (
s)
Gas flow (m3/h)
Liquid flow (dm3/min)
37.5
56.3
75.0
0 20 40 60 80 100 120
0
5000
10000
15000
20000
25000
Inte
rfe
cia
l a
rea
(m
2/m
3)
Gas flow (m3/h)
Liquid flow (dm3/min)
18.7
37.5
56.3
75.0
Packed columns vs. SFR system
7 m
0,7 m
0,40 m
0,24 m
Typical interfacial area in absorption column is 60-440 m2/m3
Interfacial area in SFR system is up to 20 000 m2/m3
Ajay Mandal, Gautam Kundu* and Dibyendu Mukherjee, Interfacial Area and Liquid-Side Volumetric Mass Transfer Coefficient in a Downflow Bubble
Column, The Canadian Journal of Chemical Engineering, Volume 81, April 2003, 215-219
Flow sheet of the pilot installation
Main components
1. Spinning Fluids Reactor
2. Liquid phase Reservoir
3. Liquid-liquid heat exchanger
4. Blower
5. Recirculation pump
6. Coalescer
V-2.0 V-2.1 V-2.2
55
PT FT
DN100/80
DN
80/1
5V
-3.3
5D
N15
/6
A
DN
6/15
V-3.44
GAS
ANALISER
EXHAUST
GASES
DN25COLD
WATERV-1.1
DN25DN25
FT
DN25
TT
DN25
HOT
WATER
DN25
V-1.2DN25DN25
FT TT
DN25
DN25
E-1.0
DN25
DN25
DN25
DN25
DN25
V-1
.0
DN25
V-1
DN25
SFR
E-1.0
DN
100/DN
80
DN
100/DN
80
P-1
DN50DN50
DN100/80
COLD
GASESDN25
DN25
DN15
COLD
GASES
FT
DN25
V-1.2
DN25DN25
55
PT
TT
DN25
DN25
V-2
.1
V-1.1 DN25
4
2
1
3
5
6
Design of the installation
Main components1. Spinning Fluids
Reactor
2.Liquid phase reservoir
3.Liquid-liquid heat exchanger
4.Blower
5.Recirculation pump
6.Coalescer
7.Electrical switchgear
1
2
3
4
6
5
7
1
6
2
1
2
6
Control system for the pilot installation
0 1000 2000
5
10
15
20
25
Tem
pera
ture
[oC
]
Time (s)
Liquid inlet
Liquid outlet
0 500 1000 1500 2000 2500
0
20
40
60
80
100
120
140
160
180
Tem
pera
ture
[oC
]
Time (s)
Gas inlet
Gas outlet
• Determining optimal ratio of gas and liquid flow
• Analysis of exhaust gases purification
• Determining the degree of fine particles removal
• Selection of liquid phase in terms of volatility, dust collection and removal of selected components from exhaust gases
Low temperature heat recovery tests
Temperature profile during tests
Thermal analysis of heat recovery
The amount of heat transferred through the area dA can be calculated from below equation:
where Th and Tc are the local temperatures of the hot and cold fluids. α is the local heat transfer coefficient and dA is the local incremental area on which α is based.
The overall heat transfer coefficient U is given by equation:
For constant temperatures and heat transfer coefficients below equation can be used:
𝑑 ሶ𝑄 = 𝑈 𝑇ℎ − 𝑇𝑐 dA
1
𝑈=
1
𝛼ℎ+
1
𝛼𝑐
ሶ𝑄 = 𝑈 𝑇ℎ − 𝑇𝑐 A
The thermal analysis of heat recovery
The amount of heat transferred in SFR can be calculated from equation:
The enthalpy if streams can be calculated from
If we assume: ሶ𝑄𝑙 = 0
If we know A we can calculate U
Other assumption: P=const. W=0
𝐻𝑔ℎ 𝐻𝑔𝑐
𝐻𝑐ℎ
𝐻𝑐𝑐
ሶ𝑄𝑙
ሶ𝑄 = 𝐻𝑔ℎ −𝐻𝑔𝑐 = 𝐻𝑐ℎ −𝐻𝑐𝑐 + ሶ𝑄𝑙
𝐻𝑖𝑇 = 𝐻𝑖
0 + න
𝑇0
𝑇
𝑓(𝑐𝑝)𝑑𝑇
𝐻𝑔ℎ −𝐻𝑔𝑐 = 𝐻𝑐ℎ −𝐻𝑐𝑐 = 𝑈 𝑇ℎ − 𝑇𝑐 A
Simulations/calculations of low temperatureheat recovery using SFR
19.405 kW
1.273 kW
HE
AT R
EC
OV
ER
Y
18.603 kW
2.075 kW
Electrical power
Exhaust gases
Energy lost - 1,1%
Heat recovery 98,9%
Assumptions:
▪ Exhaust gas temperature 500°C
▪ Gas phase flow rate 60 Nm3/h
▪ Temperature of hot and cold liquid phase, respectively 85 and 40°C
Design of four-unit SFR module
Cross-section of multi-SFR
heat recovery system
Top view of SFR head arrangement
in heat recovery module
Principle of generation
of absorbent swirl flow
Final Comments
Study visits and workshops will be organized at several
companies in Pomerania, during which the prototype
installation for heat recovery will be demonstrated.
Nevertheless, extra funds are needed.
The ability to directly familiarize participants with the
functioning of the installation and asking questions will
allow to verify thoughts, mutually inspire and exchange
ideas.
Thus new cases of industrial symbiosis can be identified.
Thank you for yuour kind attention