Date post: | 22-Jan-2015 |
Category: |
Technology |
Upload: | 4th-international-conference-on-advances-in-energy-research-icaer-2013 |
View: | 115 times |
Download: | 3 times |
Biomass Based Net CO2-negative Cogeneration – Performance
Study Using ASPEN Plus®
Kuntal Jana and Sudipta De*Department of Mechanical Engineering
Jadavpur UniversityKolkata- 700032
India
Some future options with fossil fuels………
• IGCC with carbon capture (pre-combustion or post-combustion)
Oxy-fuel combustion and CO2 capture and storage
Membranes specific for certain gases – O2, CO2, H2 etc. and integration with existing technology
Global Primary Bioenergy Supply
Global Bioenergy Electricity Generation 2000-10
Possible options ………..…..
• Biomass based power (CO2 – neutral).• Improving energy efficiency and environment
performance (Cogeneration, Gasification)• Reducing CO2 emission even more (net CO2 –
negative)
• Combining all these – possible future sustainable options with efficient and net CO2- negative power generation units.
• Challenges – technology maturity, scaling up….
Objective of the Present Work
Objective• Model development of biomass integrated
gasification combined cogeneration (BIGCC) with CO2 capture
• Simulation of the model by using ASPEN Plus®
• Defining a non-dimensional thermodynamic performance parameter- capture performance
• Finding the optimum degree of CO2 capture, based on thermodynamic performance, i.e., capture performance
Schematic of biomass integrated gasification combined cogeneration with post-combustion CO2 capture
AIR COMPRESSOR
GASIFIER
GAS COOLER
SYNGAS CLEANER
COMBUSTOR
SUPERHEATER-REHEATER
SYNGAS COMPRESSOR
GAS TURBINE
ECONOMIZER-EVAPORATOR
HEATER
PUMP
CONDENSER
Biomass
Air AshSyngas
Air
Water
STEAM TURBINE
Steam
DRIER
Gasification GT-Cycle
ST-Cycle
CO2 CAPTURE
CO2
Vent gas
CONDENSER
CO2 Product
ABSORBER
FLUE GAS COOLER
SOX REMOVAL UNIT
AMINE TREATMENT PLANT
RICH-LEAN AMINE HEAT EXCHANGER
STRIPPER
Flue gas
Flue gas (40oC)
PUMP
Make-up amine
Amine (40oC)
Rich-amine solution
Lean-amine solution
Vent-gas
Reboiler
CO2 Product
Schematic of amine based CO2 capture process
RSTOIC
DRY-FLSH
RYI ELD
RGIBBS
BIOMASS
WET-BIODRY-BI O
WATER
DECOMP
GIBS-OUT
Q-DECOMP
GASI -AIR
SEPARATE
SOLI D
SYN-GAS
COLD-SYN
GAS-SEP
H2S
AMONI A
GT-SYN
SYN-COMP
GT-COMB
COMP-SYN
AIR-COMP
GT-AIR
COMP-AI R
COMB-GAS GAS-TURB
HOT-FLUECOMP-WRK
SYN-COMW
GT-WORKW
SPRH
FLUE-OUT
RH-IN
RH-OUT
SPH-INSPH-OUT
HP-ST
ECO-EVAFLU-EXIT
LP-ST
PUMP
FEED-WTR
ECO-IN
LP-OUT
HP-WRKW
LP-WRKW
PUMP-W RK
COND
Q-COND
Q
FLU-EXHS
SYN-OUT
DRI ER
HOT-BI O
PR-WTRI N
PRW TROUT
C-SEPS3
C-ASH
B20TO-ATMP
S48
B18
PRO-HT
S5
ASPEN Plus® model of BIGCC
AB
LEANMEA
FLUEGAS
TREATGAS
RICHMEA
PUMP
POUT
HOUT
STRIP
CO2OUT
MEAOUT
Q-REB
Q
COOLER
COL-FLU
HX
COL-MEA
H2O-IN H2O-OUT
HEATER
STRIPIN
Q-MEAQ
ASPEN Plus® model of Post-combustion CO2 capture
Model development & Simulation
• Simulation Software – ASPEN Plus ® (Developed by MIT, DOE – USA)
• Biomass feed rate – 1000 kg/hr of sugarcane bagasse• Property methods:
1. Gasification and GT-power generation - Peng-Robinson equation of state with Boston Mathias alpha function (PR-BM)
2. Carbon capture process - Electrolyte Non Random Two Liquid (ELECNRTL)
3. Steam turbine power generation and process-steam generation - Steam table (STEAM TA)
Operating ParametersConfigurations Parameters Value
Reaction in gasification PressureEquivalence ratio
1atm 25% of stoichiometric air
Air compression,Syngas compression
Pressure ratioIsentropic efficiency
140.9
Combustion air Mass flow rate 25% excess of stoichiometric air
Gas cleaning Separation efficiency of solids particles 85%
Gas turbine combustor PressureHeat duty
14atm0
Gas turbine Discharge pressureIsentropic efficiency
1atm0.9
Superheater-Reheater HP stage temperatureHP stage pressure
LP stage temperatureLP stage pressure
5380C12.4MPa
5000C3.2MPa
Feed water for ST cycle TemperaturePressure
250C1atm
HP and LP Steam turbine Isentropic efficiencyLP-ST discharge pressure
0.92 0.07MPa
Lean amine solution TemperaturePressure
Amine concentration
400C1.7 bar
30% by mass
Lean loading CO2/amine (mole basis) 32%
Stripper column Calculation typeNo. of stages
Condenser typeCondenser pressure
Reboiler typeDistillate rateReflux ratio
Equilibrium20
Partial vapor10 psiaKettle
1000 Kg/hr0.10
Results
Heat consumption, Utility heat and net reboiler heat of BIGCC with post-
combustion CO2 capture
Variation of net-reboiler heat duty with carbon capture efficiency
Power output of BIGCC with post-combustion CO2 capture
NET GT-POWER (MW) LPST-POWER (MW) HPST-POWER (MW) TOTAL POWER (MW)0
0.5
1
1.5
2
2.5
REBOILER HEAT DUTY (MW)
UTILITY HEAT (MW)
NET REBOILER HEAT DUTY
(MW)
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
Variation of capture performance with carbon capture efficiency
Conclusions
• Reboiler heat duty increases sharply beyond 50% of CO2 capture
• For plants with CO2 capture, utility heat may be utilized for CO2 capture process
• For net CO2 negative plant, operational condition may be thermodynamically optimized with selection of suitable carbon capture efficiency (say, for this study 0-0.5).