Development of Low NOx Combustion Technology in Medium-Btu Fueled 1300°C-Class Gas Turbine Combustor in an Integrated Coal Gasification Combined Cycle

2002 ◽  
Vol 125 (1) ◽  
pp. 1-10 ◽  
Author(s):  
T. Hasegawa ◽  
T. Hisamatsu ◽  
Y. Katsuki ◽  
M. Sato ◽  
H. Koizumi ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Coal Gasification ◽  
Combined Cycle ◽  
Nox Emission ◽  
Nitrogen Injection ◽  
Coal Gasifier ◽  
Coal Fuel ◽  
Thermal Nox ◽  
Low Nox Emission

The development of integrated coal gasification combined cycle (IGCC) systems ensures higher thermal efficiency and environmentally sound options for supplying future coal utilizing power generation needs. The Japanese government and electric power industries in Japan promoted research and development of an IGCC system using an air-blown entrained-flow coal gasifier. On the other hand, Europe and the United States are now developing the oxygen-blown IGCC demonstration plants. Gasified coal fuel produced in an oxygen-blown entrained-flow coal gasifier, has a calorific value of 8–13 MJ/m3 which is only 1/5–1/3 that of natural gas. However, the flame temperature of medium-Btu gasified coal fuel is higher than that of natural gas and so NOx production from nitrogen fixation is expected to increase significantly. In the oxygen-blown IGCC, a surplus nitrogen produced in the air-separation unit (ASU) is premixed with gasified coal fuel (medium-Btu fuel) and injected into the combustor, to reduce thermal-NOx production and to recover the power used for the ASU. In this case, the power to compress nitrogen increases. Low NOx emission technology which is capable of decreasing the power to compress nitrogen is a significant advance in gas turbine development with an oxygen-blown IGCC system. Analyses confirmed that the thermal efficiency of the plant improved by approximately 0.3% (absolute) by means of nitrogen direct injection into the combustor, compared with a case where nitrogen is premixed with gasified coal fuel before injection into the combustor. In this study, based on the fundamental test results using a small diffusion burner and a model combustor, we designed the combustor in which the nitrogen injection nozzles arranged on the burner were combined with the lean combustion technique for low-NOx emission. In this way, we could reduce the high-temperature region, where originated the thermal-NOx production, near the burner positively. And then, a combustor with a swirling nitrogen injection function used for a gas turbine, was designed and constructed, and its performance was evaluated under pressurized conditions of actual operations using a simulated gasified coal fuel. From the combustion test results, the thermal-NOx emission decreased under 11 ppm (corrected at 16% O2 ), combustion efficiency was higher than 99.9% at any gas turbine load. Moreover, there was different effects of pressure on thermal-NOx emission in medium-Btu fuel fired combustor from the case of a natural gas fired combustor.

Development of Low NOx Combustion Technology in Medium-Btu Fueled 1300 °C-Class Gas Turbine Combustor in IGCC

2000 ◽  
Author(s):  
Takeharu Hasegawa ◽  
Tohru Hisamatsu ◽  
Yasunari Katsuki ◽  
Mikio Sato ◽  
Hiromi Koizumi ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Nox Emission ◽  
Test Results ◽  
Nitrogen Injection ◽  
Coal Gasifier ◽  
Coal Fuel ◽  
Thermal Nox ◽  
Low Nox Emission

The development of integrated coal gasification combined cycle (IGCC) systems ensures higher thermal efficiency and environmentally sound options for supplying future coal utilizing power generation needs. The Japanese government and electric power industries in Japan promoted research and development of an IGCC system using an air-blown entrained-flow coal gasifier. On the other hand, Europe and the United States are now developing the oxygen-blown IGCC demonstration plants. Gasified coal fuel produced in an oxygen-blown entrained-flow coal gasifier, has a calorific value of 8–13MJ/m3 which is only 1/5–1/3 that of natural gas. However, the flame temperature of medium-Btu gasified coal fuel is higher than that of natural gas and so NOx production from nitrogen fixation is expected to increase significantly. In the oxygen-blown IGCC, a surplus nitrogen produced in the air-separation unit (ASU) is premixed with gasified coal fuel (medium-Btu fuel) and injected into the combustor, to reduce thermal-NOx production and to recover the power used for the ASU. In this case, the power to compress nitrogen increases. Low NOx emission technology which is capable of decreasing the power to compress nitrogen is a significant advance in gas turbine development with an oxygen-blown IGCC system. Analyses confirmed that the thermal efficiency of the plant improved by approximately 0.3 percent (absolute) by means of nitrogen direct injection into the combustor, compared with a case where nitrogen is premixed with gasified coal fuel before injection into the combustor. In this study, based on the fundamental test results using a small diffusion burner and a model combustor, we designed the combustor in which the nitrogen injection nozzles arranged on the burner were combined with the lean combustion technique for low-NOx emission. In this way, we could reduce the high temperature region, where originated the thermal-NOx production, near the burner positively. And then, a combustor with a swirling nitrogen injection function used for a gas turbine, was designed and constructed, and its performance was evaluated under pressurized conditions of actual operations using a simulated gasified coal fuel. From the combustion test results, the thermal-NOx emission decreased under 11ppm (corrected at 16% O2), combustion efficiency was higher than 99.9% at any gas turbine load. Moreover, there was different effects of pressure on thermal-NOx emission in medium-Btu fuel fired combustor from the case of natural gas fired combustor.

Effect of Pressure on Emission Characteristics in LBG-Fueled 1500°C-Class Gas Turbine

1998 ◽  
Vol 120 (3) ◽  
pp. 481-487 ◽  
Author(s):  
T. Hasegawa ◽  
M. Sato ◽  
T. Ninomiya
Keyword(s):  
Gas Turbine ◽  
Coal Gasification ◽  
Load Condition ◽  
Cost Effective ◽  
Combustion Method ◽  
Combined Cycle ◽  
Nox Emission ◽  
Structure Transition ◽  
Transition Piece ◽  
Cooling Air

Developing integrated coal gasification combined cycle (IGCC) systems ensures cost-effective and environmentally sound options for supplying future power generation needs. In order to enhance thermal efficiency of IGCC and to reduce NOx emission, a 1500°C-class gas turbine combustor for IGCC was designed, tested, and the performance of the combustor was evaluated under pressurized conditions. The designed combustor had the following three characteristics: (1) in order to assure the stable combustion burning low-Btu gas (LBG), an auxiliary combustion chamber was installed at the entrance of the combustor; (2) to reduce fuel NOx emission that was produced from the ammonia (NH3) in the fuel, the rich-lean combustion method was introduced; and (3) to compensate for the declined cooling-air associated with the higher temperature of the gas turbine, the tested combustor was equipped with a dual-structure transition piece so that the cooling air in the transition piece can be recycled to cool down the combustor liner wall. As a result of combustor tests, it is confirmed that CO emission is less than 20 ppm, the conversion rate of NH3 which contains about 1000 ppm in the coal gasified fuel to NOx shows 40 percent or below, and the liner wall temperature remained below almost 850°C under high pressure (1.4 MPa), rated load condition.

Combustion Performance in a Semiclosed Cycle Gas Turbine for IGCC Fired With CO-Rich Syngas and Oxy-Recirculated Exhaust Streams

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Takeharu Hasegawa
Keyword(s):  
Gas Turbine ◽  
Coal Gasification ◽  
Combustion Process ◽  
Equilibrium Concentration ◽  
Combined Cycle ◽  
Reaction Heat ◽  
Highly Efficient ◽  
Coal Fuel ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Our study found that burning a CO-rich gasified coal fuel, derived from an oxygen–CO2 blown gasifier, with oxygen under stoichiometric conditions in a closed cycle gas turbine produced a highly-efficient, oxy-fuel integrated coal gasification combined cycle (IGCC) power generation system with CO2 capture. We diluted stoichiometric combustion with recycled gas turbine exhaust and adjusted for given temperatures. Some of the exhaust was used to feed coal into the gasifier. In doing so, we found it necessary to minimize not only CO and H2 of unburned fuel constituents but also residual O2, not consumed in the gas turbine combustion process. In this study, we examined the emission characteristics of gasified-fueled stoichiometric combustion with oxygen through numerical analysis based on reaction kinetics. Furthermore, we investigated the reaction characteristics of reactant gases of CO, H2, and O2 remaining in the recirculating gas turbine exhaust using present numerical procedures. As a result, we were able to clarify that since fuel oxidation reaction is inhibited due to reasons of exhaust recirculation and lower oxygen partial pressure, CO oxidization is very sluggish and combustion reaction does not reach equilibrium at the combustor exit. In the case of a combustor exhaust temperature of 1573 K (1300 °C), we estimated that high CO exhaust emissions of about a few percent, in tens of milliseconds, corresponded to the combustion gas residence time in the gas turbine combustor. Combustion efficiency was estimated to reach only about 76%, which was a lower value compared to H2/O2-fired combustion while residual O2 in exhaust was 2.5 vol%, or five times as much as the equilibrium concentration. On the other hand, unburned constituents in an expansion turbine exhaust were slowed to oxidize in a heat recovery steam generator (HRSG) flue processing, and exhaust gases reached equilibrium conditions. In this regard, however, reaction heat in HRSG could not devote enough energy for combined cycle thermal efficiency, making advanced combustion technology necessary for achieving highly efficient, oxy-fuel IGCC.

scholarly journals High Temperature Combustor Designed for Operation With Coal Derived Low Btu Gaseous Fuels

1980 ◽  
Author(s):  
T. R. Koblish ◽  
L. M. Nucci
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Coal Gasification ◽  
Gas Turbine Engine ◽  
Combined Cycle ◽  
Department Of Energy ◽  
Turbine Engine ◽  
Gaseous Fuels ◽  
Coal Gasifier ◽  
Engine Components

Studies sponsored by the U. S. Department of Energy (DOE) have indicated that the combined cycle, incorporating an open cycle gas turbine having a Low Btu gas (LBG) fueled combustor operating at temperatures over 2600 F and a closed cycle steam turbine can produce cost competitive electric power from gasified coal. For increased efficiency, the coal gasification system would be integrated with the gas turbine which supplies the compressed air for the coal gasification system, and the steam turbine which supplies the steam for the gasification system. The coal gasifier would provide a pressurized low heating value (LBG) fuel (at the order of ISO Btu/SCF (5590 kJ/m3) for combustion in the gas turbine engine. Under DOE sponsorship, one of the gas turbine engine components being investigated both analytically and experimentally, is the LBG fueled combustor. This paper describes the LBG configuration background technology utilized in the design of the combustor and the test program outline for substantiation of the design approach.

scholarly journals The GE Rich-Quench-Lean Gas Turbine Combustor

1998 ◽  
Vol 120 (3) ◽  
pp. 502-508 ◽  
Author(s):  
A. S. Feitelberg ◽  
M. A. Lacey
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Coal Gasification ◽  
Perforated Plate ◽  
Combined Cycle ◽  
Development Effort ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
Chemical Kinetic Model ◽  
The Rich

The General Electric Company has developed and successfully tested a full-scale, F-class (2550°F combustor exit temperature), rich-quench-lean (RQL) gas turbine combustor, designated RQL2, for low heating value (LHV) fuel and integrated gasification combined cycle applications. Although the primary objective of this effort was to develop an RQL combustor with lower conversion of fuel bound nitrogen to NOx than a conventional gas turbine combustor, the RQL2 design can be readily adapted to natural gas and liquid fuel combustion. RQL2 is the culmination of a 5 year research and development effort that began with natural gas tests of a 2” diameter perforated plate combustor and included LHV fuel tests of RQL1, a reduced scale (6” diameter) gas turbine combustor. The RQL2 combustor includes a 14” diameter converging rich stage liner, an impingement cooled 7” diameter radially-stratified-quench stage, and a backward facing step at the entrance to a 10” diameter film cooled lean stage. The rich stage combustor liner has a novel double-walled structure with narrow circumferential cooling channels to maintain metal wall temperatures within design limits. Provisions were made to allow independent control of the air supplied to the rich and quench/lean stages. RQL2 has been fired for almost 100 hours with LHV fuel supplied by a pilot scale coal gasification and high temperature desulfurization system. At the optimum rich stage equivalence ration NOx emissions were about 50 ppmv (on a dry, 15 percent O2 basis), more than a factor of 3 lower than expected from a conventional diffusion flame combustor burning the same fuel. With 4600 ppmv NH3 in the LHV fuel, this corresponds to a conversion of NH3 to NOx of about 5 percent. As conditions were shifted away from the optimum, RQL2 NOx emissions gradually increased until they were comparable to a standard combustor. A chemical kinetic model of RQL2, constructed from a series of ideal chemical reactors, matched the measured NOx emissions fairly well. The CO emissions were between 5 and 30 ppmv (on a dry, 15 percent O2 basis) under all conditions.

Computational Fluid Dynamics Simulation of Syngas Nozzle of Gas Turbine for Syngas

2019 ◽  
Author(s):  
Bo Zhang ◽  
Ye Qin ◽  
Shaoping Shi ◽  
Shu Yan ◽  
Yanfei Mu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Natural Gas ◽  
Gas Turbine ◽  
Coal Gasification ◽  
Flame Stabilization ◽  
Combined Cycle ◽  
Dynamics Simulation ◽  
Cfd Model ◽  
Heating Value

Abstract Integrated Gasification Combined Cycle (IGCC) is a technology that integrates the coal gasification and combined cycle to produce electricity efficiently. Due to the fact that the heating value of syngas from coal gasification process is typically lower than that of the natural gas, the conventional gas turbine will have to be adapted for syngas. The nozzle adjustment is the key to the successful transformation since the ignition properties are different between syngas and natural gas which have totally different compositions. The nozzles suitable for natural gas have been prone to partially melting around the flame stabilization holes on sidewalls of the nozzle in real operation. Thus a computational fluid dynamics (CFD) model was constructed for the syngas nozzles as well as combustion chamber of the gas turbine for low heating value syngas to study the thermostability of the nozzle. The detailed structure of the syngas nozzle, the combustion characteristics of syngas, as well as the actual operation condition of the gas turbine were all employed in the CFD model to improve the simulation accuracy. The reason of partially melting of the nozzles suitable for natural gas can be attributed to that the syngas leaked from the flame stabilization holes into the mainstream air can quickly mix with air, adhere to the sidewalls of the nozzles and then ignite around the holes which result in temperatures high enough to melt the material of the nozzle around the holes through CFD simulation. Finally, a new structure of the syngas nozzle was proposed and validated by CFD simulations. The simulation result shows that the flames caused by the syngas leaked from the flame stabilization holes are no longer adhering to the nozzle sidewalls and local high temperature can be lowered by about 30% which will not be able to melt the nozzle material.

scholarly journals The GE Rich-Quench-Lean Gas Turbine Combustor

1997 ◽  
Author(s):  
Alan S. Feitelberg ◽  
Michael A. Lacey
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Coal Gasification ◽  
Perforated Plate ◽  
Combined Cycle ◽  
Development Effort ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
Chemical Kinetic Model ◽  
The Rich

The General Electric Company has developed and successfully tested a full-scale, ‘F’ class (2550°F combustor exit temperature), rich-quench-lean (RQL) gas turbine combustor, designated RQL2, for low heating value (LHV) fuel and integrated gasification combined cycle applications. Although the primary objective of this effort was to develop an RQL combustor with lower conversion of fuel bound nitrogen to NOx than a conventional gas turbine combustor, the RQL2 design can be readily adapted to natural gas and liquid fuel combustion. RQL2 is the culmination of a 5 year research and development effort that began with natural gas tests of a 2″ diameter perforated plate combustor and included LHV fuel tests of RQL1, a reduced scale (6″ diameter) gas turbine combustor. The RQL2 combustor includes a 14″ diameter converging rich stage liner, an impingement cooled 7″ diameter radially-stratified-quench stage, and a backward facing step at the entrance to a 10″ diameter film cooled lean stage. The rich stage combustor liner has a novel double-walled structure with narrow circumferential cooling channels to maintain metal wall temperatures within design limits. Provisions were made to allow independent control of the air supplied to the rich and quench/lean stages. RQL2 has been fired for almost 100 hours with LHV fuel supplied by a pilot scale coal gasification and high temperature desulfurization system. At the optimum rich stage equivalence ratio NOx emissions were about 50 ppmv (on a dry, 15% O2 basis), more than a factor of 3 lower than expected from a conventional diffusion flame combustor burning the same fuel. With 4600 ppmv NH3 in the LHV fuel, this corresponds to a conversion of NH3 to NOx of about 5%. As conditions were shifted away from the optimum, RQL2 NOx emissions gradually increased until they were comparable to a standard combustor. A chemical kinetic model of RQL2, constructed from a series of ideal chemical reactors, matched the measured NOx emissions fairly well. The CO emissions were between 5 and 30 ppmv (on a dry, 15% O2 basis) under all conditions.

Effect of Pressure on Emission Characteristics in LBG-Fueled 1500 °C -Class Gas Turbine

1997 ◽  
Author(s):  
Takeharu Hasegawa ◽  
Mikio Sato ◽  
Tohru Ninomiya
Keyword(s):  
Gas Turbine ◽  
Coal Gasification ◽  
Load Condition ◽  
Cost Effective ◽  
Combustion Method ◽  
Combined Cycle ◽  
Nox Emission ◽  
Structure Transition ◽  
Transition Piece ◽  
Cooling Air

Developing integrated coal gasification combined cycle (IGCC) systems ensures cost-effective and environmentally sound options for supplying future power generation needs. In order to enhance thermal efficiency of IGCC and to reduce NOx emission, a 1500 °C -class gas turbine combustor for IGCC was designed, tested and the performance of the combustor was evaluated under pressurized conditions. The designed combustor had three characteristics: 1) In order to assure the stable combustion burning low-Btu gas (LBG), an auxiliary combustion chamber was installed at the entrance of the combustor. 2) To reduce fuel NOx emission that was produced from the ammonia (NH3) in the fuel, the rich-lean combustion method was introduced. 3) To compensate for the declined cooling-air associated with the higher temperature of the gas turbine, the tested combustor was equipped with a dual-structure transition piece so that the cooling air in the transition piece can be recycled to cool down the combustor liner wall. As a result of combustor tests, it is confirmed that CO emission is less than 20ppm, the conversion rate of NH3 which contains about 1000ppm in the coal gasified fuel to NOx shows 40 percent or below, and the liner wall temperature remained below almost 850 °C under high pressure (1.4MPa), rated load condition.

scholarly journals Design and Test of a Low-NOx Advanced Rich-Lean Combustor for LBG Fueled 1300°C-Class Gas Turbine

1992 ◽  
Author(s):  
T. Nakata ◽  
M. Sato ◽  
T. Ninomiya ◽  
T. Yoshine ◽  
M. Yamada
Keyword(s):  
Gas Turbine ◽  
Coal Gasification ◽  
Combustion Process ◽  
Calorific Value ◽  
Ammonia Concentration ◽  
Combined Cycle ◽  
Combustion Stability ◽  
Fuel Gas ◽  
Gas Cleaning ◽  
Coal Gasifier

Research and development of an IGCC (Integrated Coal Gasification Combined Cycle) power generation system is being carried out as one of the advanced coal utilization technology in Japan. The coal gasified fuel, which is produced in a coal gasifier of air-blown entrained-flow type has calorific value as low as 1/10 of LNG. Furthermore, the fuel gas contains ammonia when a gas cleaning system is a hot type, and ammonia will be converted to nitrogen oxides in the combustion process of a gas turbine. The authors have designed and made an 1300°C-class advanced rich-lean combustor mainly designed for achieving low fuel-NOx combustion. By testing it under atmospheric pressure conditions, we have successfully reduced the NOx emissions (to 60 ppm corrected at 16 percent O2) by more than half the level previously achieved when the ammonia concentration was 1000 ppm. Combustion stability was adequate even when the calorific value of the fuel decreased to 2700 kJ/m3N.

Effect of Pressure on Combustion Characteristics in LBG-Fueled 1300°C-Class Gas Turbine

1994 ◽  
Vol 116 (3) ◽  
pp. 554-558 ◽  
Author(s):  
T. Nakata ◽  
M. Sato ◽  
T. Ninomiya ◽  
T. Yoshine ◽  
M. Yamada
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Coal Gasification ◽  
Combustion Process ◽  
Combined Cycle ◽  
Combustion Characteristics ◽  
Inlet Temperature ◽  
Effect Of Pressure ◽  
Coal Gasifier

Developing integrated coal gasification combined cycle systems ensures that Japan will have cost-effective and environmentally sound options for supplying future power generation needs. Reduction of NOx emissions and increasing the inlet temperature of gas turbines are the most significant issues in gas turbine development in IGCC. The coal gasified fuel, which is produced in a coal gasifier of air blown entrained-flow type has a calorific value as low as 1/10 of natural gas. Furthermore, the fuel gas contains ammonia when a gas cleaning system is a hot type, and ammonia will be converted to nitrogen oxides in the combustion process of a gas turbine. The study is performed in 1300°C-class gas turbine combustor firing coal-gasifier fuel in IGCC power generation systems. In the previous study [1] the advanced rich-lean combustor of 150-MW class gas turbine was designed to hold stable combustion burning low-Btu gas fuel and to reduce fuel NOx emission that is produced from the ammonia in the fuel. By testing it under atmospheric pressure conditions, we have studied the effects of fuel parameters on combustor performances and listed the basic data for development applications. In this study, by testing it under pressurized conditions, we have obtained a very significant result through investigating the effect of pressure on combustion characteristics and wish to provide herein a summary of our findings.

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