Combined Heat & Power Plant

Group Meeting # 2Mentor: Shannon Brown, PE

Michael BentelJeremy DavidErik Peterson

Arpit Shah

1

2

Questions from Group Meeting #1What are the specifications for fuel?

~ 80 – 85% - C2+~ 10% - CH4

~ 5 % - N2 ~ 2 % - CO2

What is the primary heat source for the boiler?Combustion gases from Gas Turbine along

with Natural GasBoiler – Heat Recovery Steam Generator

(H.R.S.G.)What is the cheapest source of fuel for

this plant? Waste hydrocarbons from **Team Alpha**

3

Questions (Cont’d)What is the minimum water purity required for

boiler feed water (BFW)? Dissolved O2: < 0.007 ppmTotal Fe: < 0.01 ppmTotal Cu: <0.01 ppmTotal Hardness: 0.05 pH: 8.8-9.6Silica: <2.00 ppmConduction < 150 Total Dissolved Solids (TDS): 0.1

How is the effluent stream from the boiler being addressed?The Effluent stream will be sent through the flue gas

purification system

Group Meeting 2 ObjectivesFlow SheetsMaterial & Energy Balances

Process Flow Sheet FrozenDataHand CalculationsRough Economics

4

Outline 1. Design Basis √2. Block Flow Diagram √3. Process Flow Diagram IN PROGRESS4. Material and Energy Balance IN PROGRESS5. Calculations IN PROGRESS6. Annotated Equipment List (Data Sheet) IN PROGRESS7. Economic Evaluation factored from Equipment Costs8. Utilities9. Conceptual Control Scheme10. General Arrangement – Major Equipment Layout11. Distribution and End-use Issues Review12. Constraints Review13. Applicable Standards IN PROGRESS14. Project Communications File IN PROGRESS15. Information Sources and References IN PROGRESS

5

Pumps and CompressorsAs stated before,

compressor is going to be used to provide plant air

Because instrument air must be very dry to avoid plugging and corrosion, a rotary screw oil free air compressor is commonly put through a dryer 6

Block Numbe

r

Unit Steam Numb

er

Stream Label

16 Compressor

S-16 Air - In

17 Dryer S-17 Plant Air

24 Surge Tank

S-18 Compressed Air

S-19 Compressed Air

S-30 Instrument Air

Air Compressor Material BalanceOil - Free

Air Compress

orRefrigerat

ed Air Dryer

P1 , T1Wet (cfm) P2, T2,

Wet (cfm)

H2O (cfm)

Dry (cfm)

Conditions

P1 11.8 Psi

T1 78 F

% Rel. Humidity 90

Air Density 0.0738 lb/ft3

1 lb Dry Air 13.92 ft3

1 lb Dry Air 0.0192 lb H2O

H20 Density 62.25 lb/ft3

n (Heat Capacity Ratio) 1.4 7

Compressed Air – Energy Balances Dryer Mass Balance ft3 * 1 lb DA/ ft3 * lb H2O/ lb DA = lb H2O * ft3/lb = cfm H2O

Work Done in Compressed Air -W=P1ν1(n/(n-1))[(P2/P1) (n-1)/n-1]

=ZRT(n/(n-1))[(P2/P1) (n-1)/n-1]

Heat of Compression: T2=T1(P2/P1)(n-1/n)

TeamP2

Required (psi) Dry (cfm) Wet (cfm) T2 F H2O (cfm) HP

India 100.00 500.000 500.20 112.96 0.01109 8.34

8

Compressor CostsAnnual Electricity Cost

=

• One of the most expensive sources of energy of plant

• 10% of electricity consumption goes to compressed air generation

• Several compressors may be installed for maintenance purposes as a stand-by spare

9

Williston, ND - DataDry Bulb Temperature : 92°F Wet Bulb Temperature: 66°FHighest Relative Humidity: 90%

10

Induced – Draft Cooling Tower PFD

11

Cooling Tower – General Material BalanceDry Air Mass Balance

ṁa1 = ṁa2 = ṁa

Water Mass Balanceṁhw + ṁa1∙ω1 = ṁcw + ṁa2∙ω2

= ṁhw- ṁcw = ṁa(ω2- ω1)Also,

ṁMU = ṁa(ω2- ω1) + ṁBD

12

Cooling Tower – Energy BalanceĖin – Ėout = ΔĖsys ΔĖsys = 0

0 = (ṁa2∙ha2) + (ṁcw∙hcw) – (ṁa1∙ha1) – (ṁhw∙hhw)

ṁa =

**Assuming Steady State and Adiabatic System**

13

Data Used to Calculate M&E BalanceStream Enthalpy (h)

(Btu/lb DA)ω

(lb H2O/lb DA)1/ρ (ft3/lb)

Air – In 22.8940 0.01706 18.2149

Air – Out 77.4935 0.1146

Hot Return Water

72.3646

Cold Process Water

33.6199

14

Results from M&E Balance - ECT

15

Stream Temperature (°F)

Humidity Flowrate (ṁ) (lb/hr)

Energy (Btu/hr)

Air – In 70 ~ 25 % 232,067 5,312,950

Air – Out 90 ~ 90 % 232,067 17,983,714

Hot Return Water

105 317,465 22,973,275

Cold Process Water

85 307,227 10,328,954

Make Up Water

85 10,238 344,209

**Calculated at 11.8 psi

Turbine & Boiler System

16

Block Labels

Block Number Block Name1 Pre-Water Treatment2 Pump3 Membrane Assembly4 EDI Module5 Resistivity Cell6 Compressor7 Combustion Chamber8 Gas Turbine9 Steam Turbine

10 Processes11 Condenser12 Stacks13 Economizer14 Evaporator15 Super heater22 Deaerator23 Header25 Separator 17

Stream Labels

Label Stream NameS-1 Plant WaterS-2 Pre - Treated WaterS-3 Pre - Treated WaterS-4 Brine DischargeS-5 Fresh WaterS-6 Pure WaterS-7 Ultrapure WaterS-8 Reheated SteamS-9 Turbine Exhaust Steam

S-10 Low Pressure SteamS-11 Condensed SteamS-12 Hot Combustion GasesS-13 Superheated SteamS-14 AirS-15 Compressed AirS-28 Waste/DischargeS-29 Natural GasS-31 Boiler Feed WaterS-32 Boiler Feed Water - Processes

Results from Boiler Material BalanceStream Flowrate ((lb/hr)

Water – In 107,000

Steam – Out 107,700

18

*Based on ideal system (100% efficiency/recovery, no lose of water/steam due to system leakage)

Results from Boiler Energy Balance

19

Sensible Heat (Btu/lb

)

ΔT (°F) Latent Heat

(Btu/lb)

Phase Change

Compression (Btu/lb)

ΔP (psig)

247.077 100 212 1908.300 Liquid Vapor

185.541 0 150

331.510 212 358 1905.334 Liquid Vapor

183.857 150 300

139.909 358 417 1785.464 Liquid Vapor

187.209 300 600

170.453 417 486 1615.044 Liquid Vapor

184.698 600 1200

222.199 486 567 1349.883 Liquid Vapor

802.285 567 1050

Superheated

*Calculated using steam tables and superheated steam tables for latent heat and superheated work, respectively; averaged heat capacity over temperature ranges for sensible heat; PV work for compression.

Flue Gas Clean UpParticle RemovalGaseous Contaminates Removal

Wet Scrubber – Utilizes water for removalWet-Dry Scrubber – Utilizes aqueous spray for

removalDry Scrubber – Utilizes dry powder for removal

Nitrogen Oxide Removal – Utilizes catalysis for removal

Stack – Measures contaminates in out flowing combustion gases

USEPA & NDEPA Flue Gas RequirementsNOx: 100 ppb, averaged over one hour SOx: 1 - hour standard at a level of 75 parts

per billion 

CO: 8 - hour primary standard at 9 parts per million (ppm) 

Turbine Material BalanceGas Turbine

Airin + Fuelin = Exhaust Gasout mAir + mfuel = mExhaust

Steam TurbineHigh Pressure Steamin = Process Steamout +

Condensing Steamout

mHigh-P = mProcess + mcondensed

22

Turbine Energy BalanceGas Turbine

Combustion Gasin = Workout + Exhaust Gasout

(m*H)Combustion = (effturbine *(m*H)Combustion + ((m*H)Combustion - effturbine *(m*H)Combustion))

Steam TurbineHigh Pressure Steamin =

Process Steamout + Condensing Steamout + Workout

(m*H)high P. = Σ(m*H)process + (m*H)condensed + effturbine *(Σ((m*H)high P – (m*H)process) + ((m*H)high

P. – (m*H)condensed)) 23

Relating Turbine and BoilerEnergy & Material BalanceEnergy - Combustion Gasin – Workout =

Exhaust Gasout = Exhaust Gasin =

Steamout + Exhaust Gasout – Feed WaterinMaterial – Airin + Fuelin =

Exhaust Gasout = Exhaust Gasin = Steamout + Exhaust Gasout – Feed Waterin

24

Results from M&E Balance – Gas TurbineStreams Flow (MMSCFD) Energy

Air 0.028 N/A

Fuel 0.0016 553,366 Btu/mol

Combusted Gas 0.03 362,257,129 Btu/day

25

Equipment ListEquipment Quantity

Reverse Osmosis System 1

Electrodeionization System 1

Water Tube Boiler 1

Gas Turbine 2

Steam Turbine 1

Compressor 1

Dryer 1

H.R.S.G System 1

Induced – Draft Cooling Tower 1

26

CHP - Rough EconomicsWhere,Ce= Purchased Equipment Costa & b = Cost ConstantsS = Size Parameter n = Exponent for that type of equipment

**All equipment costs are based on U.S. Gulf Coast Basis, Jan 2010 (CEPCI index = 532.9)**

27

Equipment Cost TableEquipment a b Supper 0.8*Supper n Ce($)

Cooling Tower

170,000

1,500

10,000 8,000 0.9 5,055,100

**Calculated Using Cost Estimation Equation in “Chemical Engineering Design”, Towler

**Calculated Using “Plant Design and Economics for Chemical Engineers” Online Simulator, 5th Edition

**Estimated Cost from GE

Equipment Cost ($)

Compressor 127,496

Steam Turbine 308,856

Gas Turbine 706,734

H.R.S.G ~20,000,000

Water Purification

System

N/A

28

Equipment Cost Equipment Quantity Cost ($)

Reverse Osmosis System

1 Waiting for Siemens to respond

Electrodeionization System

1 Waiting for Siemens to respond

Gas Turbine 2 1,413,468

Steam Turbine 1 308,856

Compressor 2 254,992

Dryer 1 10,000

H.R.S.G System 1 20,000,000

Induced – Draft Cooling Tower

1 5,055,100

29

30

Economics – Cont’dTotal Equipment Cost: $27,032,416Total Cost of Installation: $117,861,333 *Assumption: 4.36*(Cost of Equipment) Total Cost of Engineering: $8,109,724 *Assumption: Engineering costs = 0.30(Cost of Equipment)

Total Cost = Cost of Equipment + Installation + Engineering = $153,003,474

QUESTIONS???

31