Embed Size (px)
Citation preview
The Effects of Operation Parameters on the Performance of Entrained-bed Pulverized Coal
Gasifier with High Fusion Temperature Coal
Zhenghua Dai*, Zhonghua Sun, Xin Gong, Zhijie Zhou, Fuchen Wang
Institute of Clean Coal Technology Key Laboratory of Coal Gasification and Energy Chemical
Engineering of Ministry of Education East China University of Science and Technology
P2
Content
The novel syngas cooling process for IGCC system
Coal analysis data
Simulation results analysis and discussion
Conclusions
P3
1 The novel syngas cooling process for IGCC system
Typical entrained-bed coal gasification technologies
Technology coal feeding refractory lining
high temperature syngas cooling
GE coal water slurry refractory brick (I) water quenching (II) radiation boiler + convection boiler
Shell pulverized coal membrane wall recycle syngas quenching + convection boiler
OMB (Opposed -Multi -Burner)
(I) coal water slurry (II) pulverized coal
(I) refractory brick (II) membrane wall
(I) water quenching (II) radiation boiler + recycle syngas quenching + convection boiler
P4
Schematic structure of the OMB gasifier
The OMB gasifier is featured with four horizontal impinging burners, which can intensify mixing and improve residence time distribution.
P5
Pulverized coal
preparation
OMB Gasification
Filter cake and waste water
Steam
Pulverized coal
transportationOxygen
High pressure N2
Pulverized coalPulverized coal
＋N2
Steam
Syngas water scrubbing
Slag water treatment
Quenching gas
Coal
Fuel
SlagBoiler water
Grey water
Crude syngas
Crude syngas
Condensate
1
2
4
6
5
3
radiation boiler
Crude syngas
Boiler water
Steam
Black water
convection boiler
Soft water
The OMB pulverized coal gasification technology with novel syngas cooling process
This sysngas cooling process can reduce the radiation boiler length and investment.
The gas temperature at inlet of the convection boiler can be adjusted online and avoid the ash agglomeration .
1300-1700 ℃
900-1100 ℃
~280 ℃
700-900 ℃
P6
2 Coal analysis data
Proximate analysis, wt%(Dry) Ash 32.0 Volatile matter 9.0 Fixed carbon 59.0 Ultimate analysis, wt%(Dry) C 61.3 H 2.0 N 0.7 S 2.7 O 1.3 Ash 32.0
Ash analysis, wt%(Dry) SiO2 52.0 Al2O3 33.3 Fe2O3 3.7 P2O5 0.4 CaO 5.9 MgO 0.4 Na2O 0.5 K2O 1.0 SO3 1.3
P7
Flux (CaCO3) addition %
Deforming temperature(℃)
Softening temperature(℃)
Fusion temperature(℃)
0 1441 ＞1550 ＞1550 3 1376 1413 1429 5 1311 1344 1355
Ash fusion temperature with Flux(CaCO3)
P8
1250 1300 1350 1400 1450 1500 1550 1600 16500
20
40
60
80
100 0%CaCO3
3%CaCO3
5%CaCO3
Visc
osity
(Pa.s
)
Temperature(℃)
Viscosity-Temperature characteristics of coal ash with Flux(CaCO3)
1375 ℃ 1450 ℃ 1600 ℃
P9
DRY-COAL INBURNER
QTRANSFE
OXYGEN
N2
QLOSTQ
STEAM
FUEL
PORDUCT
RYIELD
DECOMP
RGIBBS
BURN
3 Simulation results analysis and discussion
Simulation diagram of the OMB pulverized coal gasifier
Dai, ZH, etc. Pilot-trial and modeling of a new type of pressurized entrained-flow pulverized coal gasification technology. Fuel 2008; 87: 2304-2313
0.51.01.52.02.53.03.54.0
1300 1400 1500 1600 1700
gasification temperature C
Heat loss %
P10
Operation conditions Operation pressure,MPa(G) 4.0 Coal flow rate, t/h 80.5 Oxygen flow rate, Nm3/h 40008 Oxygen purity, % 99.6 Nitrogen flow rate, Nm3/h 9200 Middle pressure steam flow rate, t/h 15.1
boiler water flow rate, t/h ~18
Gasification performance Gasifier temperature, ℃ 1600 Gasifier heat loss(2.5%), GJ/h 45 Steam by membrane wall, t/h 13 H2, mol% (dry basis) 23.9 CO, mol% (dry basis) 64.9 CO2, mol% (dry basis) 2.8 CH4, mol% (dry basis) 0.0037 Carbon Conversion, % 99 Specific coal consumption, kg(dry basis)/kNm3(CO+H2)
668
Specific oxygen consumption, Nm3 /kNm3(CO+H2)
332
The basic operation conditions and gasification performance with no flux
P11
Effects of oxygen coal ratio and steam coal ratio on the gasification performance
P12
The oxygen coal ratio and steam coal ratio are required to adjust at the same time.
When The fluctuation range of coal flow rate is +/-5%, the fluctuation range of gasification temperature is 280 ℃.
As increasing the heat loss of the gasifier from 0.9% (1300 ℃) to 3.6% (1700℃), the oxygen and coal consumption increases 18% and 7% respectively.
P13
Effects of ash content on the gasification performance
Base coal Coal 1 Coal 2
Proximate analysis (wt%,dry basis)
Ash 32 22.8 15.9 V 9 10.2 11.1 FC 59 67 73 Ultimate analysis (wt%,DAF)
Operation conditions Base coal Coal 1 Coal 2
Gasifier perssure, MPa(G) 4 Gasification temp ℃ 1600 Oxygen-coal ratio,Nm3/t coal 497 544 584 Steam coal ratio, kg/tcoal 188 250 287 Gasification performance Carbon conversion,% 99 99 99 Specific coal consumption,
668 589 535 kg coal/kNm3(CO+H2) Specific oxygen consumption,
332 320 312 Nm3 oxygen/kNm3(CO+H2)
The coal quality has great effect on the operation conditions and gasification performance.
When The fluctuation range of coal ash content % is +/-2, the fluctuation range of gasification temperature is 140 ℃.
P14
Effects of adding flux on the gasification performance
0 3% 5% Temp. 1600 ℃ 1450 ℃ 1375 ℃ Heat loss 2.50% 1.80% 1.40%
600
620
640
660
680
700
1 2 3Flux(CaCO3)
Specific coal
consumption
0% 3% 5%
The proper addition of flux (CaCO3) can observably reduce the coal and oxygen consumption.
250
270
290
310
330
350
1 2 3Flux(CaCO3)
Specific oxygen
consumption
0% 3% 5%
P15
4 Conclusions
OMB pulverized coal gasification technology with novel syngas cooling process is proper for IGCC.
For pulverized coal gasification, the steady of coal flow rate, the steady of coal quality and measurement of coal flow rate are very important.
The operation parameters are related to the ash content, ash fusion temperature, ash viscosity-temperature characteristics, heat loss of gasifier, etc. These parameters are combined to determine optimal gasification performance and operation stability.
