The Experts below are selected from a list of 36108 Experts worldwide ranked by ideXlab platform
Yuegui Zhou - One of the best experts on this subject based on the ideXlab platform.
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numerical optimization of the influence of multiple deep air staged combustion on the NOx Emission in an opposed firing utility boiler using lean coal
Fuel, 2020Co-Authors: Yongqiang Wang, Yuegui ZhouAbstract:Abstract Multiple deep air-staged combustion is a promising technology to significantly reduce NOx Emission in the opposed firing utility boilers using low-volatile coal. The gas-solid two-phase flow, pulverized coal combustion and NOx Emission characteristics of an existing 600 MW coal-fired boiler were numerically simulated to evaluate the influence of excess air coefficient in primary combustion zone (αM), variational air distribution modes and multiple deep air-staged combustion on the NOx formation and destruction process in the furnace. The detailed NOx formation and reduction models were proposed to consider the reduction reaction between hydrocarbon and NO under fuel rich conditions and well validated by the experimental results in the laboratory and field tests. The results show that the αM has an important influence on flue gas temperature distribution and forms a reducing atmosphere in the primary combustion zone to significantly reduce NOx concentration. The NOx concentration at the furnace outlet is greatly decreased when the deep air-staged combustion is adopted with αM of 0.75, and the CO concentration maintains within a lower level. Compared with the balanced air distribution, the pagoda and inverse pagoda air distributions are found to be ineffective to enhance NOx reduction performance under deep air-staged combustion. However, the pagoda air distribution effectively reduces NOx Emission under middle air-staged combustion condition. The NOx Emission is further reduced by adopting the multiple air-staged combustion due to the higher CO concentration formed in the burnout zone. The results are helpful to the design and operation optimization of the opposed firing utility boilers using lean coal.
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Mechanism analysis on the pulverized coal combustion flame stability and NOx Emission in a swirl burner with deep air staging
Journal of the Energy Institute, 2019Co-Authors: Chaoyang Zhou, Yongqiang Wang, Qiye Jin, Qijuan Chen, Yuegui ZhouAbstract:Abstract Low NOx burner and air staged combustion are widely applied to control NOx Emission in coal-fired power plants. The gas-solid two-phase flow, pulverized coal combustion and NOx Emission characteristics of a single low NOx swirl burner in an existing coal-fired boiler was numerically simulated to analyze the mechanisms of flame stability and in-flame NOx reduction. And the detailed NOx formation and reduction model under fuel rich conditions was employed to optimize NOx Emissions for the low NOx burner with air staged combustion of different burner stoichiometric ratios. The results show that the specially-designed swirl burner structures including the pulverized coal concentrator, flame stabilizing ring and baffle plate create an ignition region of high gas temperature, proper oxygen concentration and high pulverized coal concentration near the annular recirculation zone at the burner outlet for flame stability. At the same time, the annular recirculation zone is generated between the primary and secondary air jets to promote the rapid ignition and combustion of pulverized coal particles to consume oxygen, and then a reducing region is formed as fuel-rich environment to contribute to in-flame NOx reduction. Moreover, the NOx concentration at the outlet of the combustion chamber is greatly reduced when the deep air staged combustion with the burner stoichiometric ratio of 0.75 is adopted, and the CO concentration at the outlet of the combustion chamber can be maintained simultaneously at a low level through the over-fired air injection of high velocity to enhance the mixing of the fresh air with the flue gas, which can provide the optimal solution for lower NOx Emission in the existing coal-fired boilers.
K A Subramanian - One of the best experts on this subject based on the ideXlab platform.
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control of backfire and NOx Emission reduction in a hydrogen fueled multi cylinder spark ignition engine using cooled egr and water injection strategies
International Journal of Hydrogen Energy, 2019Co-Authors: Vipin Dhyani, K A SubramanianAbstract:Abstract The experimental study was carried out on a constant speed multi-cylinder spark ignition engine fueled with hydrogen. Exhaust gas recirculation (EGR) and water injection techniques were adopted to control combustion anomalies (backfire and knocking) and reduce NOx Emission at source level. The experimental tests were conducted on the engine with varied EGR rate (0%–28% by volume) and water to hydrogen ratio (WHR) (0–9.25) at 15 kW load. It was observed from the experiments that both the strategies can control backfire effectively, but water injection can effectively control backfire compared to EGR. The water injection and EGR reduce the probability of backfire occurrence and its propagation due to the increase in the requirement of minimum ignition energy (MIE) of the charge, caused mainly due to charge dilution effect, and reduction in flame speed respectively. The NOx Emission was continuously reduced with increase in EGR rate and WHR, but at higher rates (of EGR and WHR), there was an issue of stability of engine operation. It was found from the experimental results that at 25% EGR, there was 57% reduction in NOx Emission without drop in brake thermal efficiency whereas, with WHR of 7.5, the NOx Emission was reduced by 97% without affecting the efficiency. The salient point emerging from the study is that water injection technique can control backfire with ultra-low (near zero) NOx Emission without compromising the performance of the hydrogen fueled spark ignition engine.
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experimental investigation on effects of compression ratio and exhaust gas recirculation on backfire performance and Emission characteristics in a hydrogen fuelled spark ignition engine
International Journal of Hydrogen Energy, 2016Co-Authors: B L Salvi, K A SubramanianAbstract:Abstract The experimental study was conducted on single cylinder, forced air cooled hydrogen fuelled spark ignition (SI) generator set, which was converted from gasoline fuelled generator set with rated power 2.1 kVA at 3000 rpm. The study was carried out at various compression ratios (4.5:1, 6.5:1 (base) and 7.2:1), spark timings (2–20 °CA before top dead centre (bTDC)) and exhaust gas recirculation (EGR) up to 25% by Volume. Furthermore, the experimental tests were conducted on the engine with varied start of gas injection (SOI) at various compression ratios in order to find the backfire limiting start of injection (BFL-SOI). The results indicated that engine operation at higher compression ratio improved the brake thermal efficiency and reduced the backfire occurrence as residual gas fraction decreased with increased compression ratio. However, NOx Emission increased with increased compression ratio. In order to reduce the NOx Emission at source level, the engine was operated with retarded spark timings and different EGR percentage. The relative NOx Emission decreased up to 10% with the spark time retarding of 2° CA bTDC from maximum brake torque (MBT) whereas it decreased about 57% with 25% by volume EGR. The delay in gas injection could reduce the chance of backfire occurrence and the BFL-SOI decreased with increased compression ratio. A notable point emerged from this study is that in hydrogen fuelled spark ignition engine the spark time retarding is not a suitable strategy for NOx Emission reduction whereas the EGR at the optimum level (20%) is a better strategy that could reduce the NOx Emission up to 50% as compared to base hydrogen engine without EGR.
Guoliang Song - One of the best experts on this subject based on the ideXlab platform.
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operating characteristics and ultra low NOx Emission of 75 t h coal slime circulating fluidized bed boiler with post combustion technology
Fuel, 2021Co-Authors: Guoliang Song, Xueting Yang, Zhao Yang, Yuan Xiao, Qinggang Lyu, Xingshun Zhang, Qingbo PanAbstract:Abstract Coal slime was a kind of industrial solid waste and it was hard to utilize. To realize the resource utilization of coal slime, a 75 t/h circulating fluidized bed (CFB) boiler with post-combustion technology was built. The operating and Emission characteristics during mono-combustion of coal slime were investigated in detail. The fuel characteristics of coal slime and feeding from the top of the furnace resulted in the temperatures at the top and the bottom were higher than the middle of the furnace. When the furnace differential pressure increased, the furnace temperature and the main steam temperature both decreased, but the main steam flow increased. The main steam temperature could significantly increase after the soot blowing. The post-combustion air (PCA) was an effective means to adjust the main steam parameters. The main steam temperature increased as PCA increasing. The average SO2 Emissions were only 8.4 mg·m−3 benefited from the excellent desulfurization effect of the combination of dry and semi-dry desulfurization. Nevertheless, due to the fluctuations of coal slime characteristics, the standard deviation of SO2 Emission reached 8.6 mg·m−3. Under the conditions without desulphurization and SNCR, the NOx Emissions of coal slime could be decreased to 38 mg·m−3 and reach the ultra-low NOx Emission when post-combustion technology was used.
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experimental study on ultra low initial NOx Emission characteristics of shenmu coal and char in a high temperature cfb with post combustion
Journal of The Energy Institute, 2020Co-Authors: Guoliang Song, Xueting Yang, Zhao Yang, Yuan XiaoAbstract:. The NOx Emission of conventional circulating fluidized bed (CFB) boilers could hardly meet the increasing strict standards in China, so the initial NOx Emission and control of Shenmu coal and char were investigated in a 0.5 MWth high temperature CFB test platform with a main combustion zone (MCZ) and a post-combustion zone (PCZ), the reducing atmosphere in MCZ suppressed the formation of NOx, high temperature in PCZ made the residual carbon and CO burnout, the technology of high temperature CFB with post-combustion had the advantage of decreasing the initial NOx Emission while maintaining the combustion efficiency of fuel. The experimental results showed that as the injection position of post-combustion air(PCA) moving backward, the reducing zone in PCZ was enlarged so more NOx could be converted to N2. When PCA was injected from PCA1 and PCA3, NOx and CO Emission were both relatively lower than other injection positions, the temperature in PCZ of Shenmu char was more uniform and its NOx Emission was lower compared to Shenmu coal, the peak temperatures of MCZ and PCC were 968 °C and 936 °C respectively, the initial NOx Emission of Shenmu coal was 46 mg/m3(at 6% O2), meanwhile, the CO Emission was 139 ppm. The initial NOx Emission of Shenmu char could reach 41 mg/m3 when the temperatures of MCZ and PCZ were 931 °C and 913 °C respectively, the new ultra-low Emission requirement (≤50 mg/m3) was successfully achieved without additional denitration equipment, so the technology of high temperature CFB with post-combustion is an effective ultra-low nitrogen combustion technology.
Yuan Xiao - One of the best experts on this subject based on the ideXlab platform.
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operating characteristics and ultra low NOx Emission of 75 t h coal slime circulating fluidized bed boiler with post combustion technology
Fuel, 2021Co-Authors: Guoliang Song, Xueting Yang, Zhao Yang, Yuan Xiao, Qinggang Lyu, Xingshun Zhang, Qingbo PanAbstract:Abstract Coal slime was a kind of industrial solid waste and it was hard to utilize. To realize the resource utilization of coal slime, a 75 t/h circulating fluidized bed (CFB) boiler with post-combustion technology was built. The operating and Emission characteristics during mono-combustion of coal slime were investigated in detail. The fuel characteristics of coal slime and feeding from the top of the furnace resulted in the temperatures at the top and the bottom were higher than the middle of the furnace. When the furnace differential pressure increased, the furnace temperature and the main steam temperature both decreased, but the main steam flow increased. The main steam temperature could significantly increase after the soot blowing. The post-combustion air (PCA) was an effective means to adjust the main steam parameters. The main steam temperature increased as PCA increasing. The average SO2 Emissions were only 8.4 mg·m−3 benefited from the excellent desulfurization effect of the combination of dry and semi-dry desulfurization. Nevertheless, due to the fluctuations of coal slime characteristics, the standard deviation of SO2 Emission reached 8.6 mg·m−3. Under the conditions without desulphurization and SNCR, the NOx Emissions of coal slime could be decreased to 38 mg·m−3 and reach the ultra-low NOx Emission when post-combustion technology was used.
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experimental study on ultra low initial NOx Emission characteristics of shenmu coal and char in a high temperature cfb with post combustion
Journal of The Energy Institute, 2020Co-Authors: Guoliang Song, Xueting Yang, Zhao Yang, Yuan XiaoAbstract:. The NOx Emission of conventional circulating fluidized bed (CFB) boilers could hardly meet the increasing strict standards in China, so the initial NOx Emission and control of Shenmu coal and char were investigated in a 0.5 MWth high temperature CFB test platform with a main combustion zone (MCZ) and a post-combustion zone (PCZ), the reducing atmosphere in MCZ suppressed the formation of NOx, high temperature in PCZ made the residual carbon and CO burnout, the technology of high temperature CFB with post-combustion had the advantage of decreasing the initial NOx Emission while maintaining the combustion efficiency of fuel. The experimental results showed that as the injection position of post-combustion air(PCA) moving backward, the reducing zone in PCZ was enlarged so more NOx could be converted to N2. When PCA was injected from PCA1 and PCA3, NOx and CO Emission were both relatively lower than other injection positions, the temperature in PCZ of Shenmu char was more uniform and its NOx Emission was lower compared to Shenmu coal, the peak temperatures of MCZ and PCC were 968 °C and 936 °C respectively, the initial NOx Emission of Shenmu coal was 46 mg/m3(at 6% O2), meanwhile, the CO Emission was 139 ppm. The initial NOx Emission of Shenmu char could reach 41 mg/m3 when the temperatures of MCZ and PCZ were 931 °C and 913 °C respectively, the new ultra-low Emission requirement (≤50 mg/m3) was successfully achieved without additional denitration equipment, so the technology of high temperature CFB with post-combustion is an effective ultra-low nitrogen combustion technology.
Yongqiang Wang - One of the best experts on this subject based on the ideXlab platform.
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numerical optimization of the influence of multiple deep air staged combustion on the NOx Emission in an opposed firing utility boiler using lean coal
Fuel, 2020Co-Authors: Yongqiang Wang, Yuegui ZhouAbstract:Abstract Multiple deep air-staged combustion is a promising technology to significantly reduce NOx Emission in the opposed firing utility boilers using low-volatile coal. The gas-solid two-phase flow, pulverized coal combustion and NOx Emission characteristics of an existing 600 MW coal-fired boiler were numerically simulated to evaluate the influence of excess air coefficient in primary combustion zone (αM), variational air distribution modes and multiple deep air-staged combustion on the NOx formation and destruction process in the furnace. The detailed NOx formation and reduction models were proposed to consider the reduction reaction between hydrocarbon and NO under fuel rich conditions and well validated by the experimental results in the laboratory and field tests. The results show that the αM has an important influence on flue gas temperature distribution and forms a reducing atmosphere in the primary combustion zone to significantly reduce NOx concentration. The NOx concentration at the furnace outlet is greatly decreased when the deep air-staged combustion is adopted with αM of 0.75, and the CO concentration maintains within a lower level. Compared with the balanced air distribution, the pagoda and inverse pagoda air distributions are found to be ineffective to enhance NOx reduction performance under deep air-staged combustion. However, the pagoda air distribution effectively reduces NOx Emission under middle air-staged combustion condition. The NOx Emission is further reduced by adopting the multiple air-staged combustion due to the higher CO concentration formed in the burnout zone. The results are helpful to the design and operation optimization of the opposed firing utility boilers using lean coal.
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Mechanism analysis on the pulverized coal combustion flame stability and NOx Emission in a swirl burner with deep air staging
Journal of the Energy Institute, 2019Co-Authors: Chaoyang Zhou, Yongqiang Wang, Qiye Jin, Qijuan Chen, Yuegui ZhouAbstract:Abstract Low NOx burner and air staged combustion are widely applied to control NOx Emission in coal-fired power plants. The gas-solid two-phase flow, pulverized coal combustion and NOx Emission characteristics of a single low NOx swirl burner in an existing coal-fired boiler was numerically simulated to analyze the mechanisms of flame stability and in-flame NOx reduction. And the detailed NOx formation and reduction model under fuel rich conditions was employed to optimize NOx Emissions for the low NOx burner with air staged combustion of different burner stoichiometric ratios. The results show that the specially-designed swirl burner structures including the pulverized coal concentrator, flame stabilizing ring and baffle plate create an ignition region of high gas temperature, proper oxygen concentration and high pulverized coal concentration near the annular recirculation zone at the burner outlet for flame stability. At the same time, the annular recirculation zone is generated between the primary and secondary air jets to promote the rapid ignition and combustion of pulverized coal particles to consume oxygen, and then a reducing region is formed as fuel-rich environment to contribute to in-flame NOx reduction. Moreover, the NOx concentration at the outlet of the combustion chamber is greatly reduced when the deep air staged combustion with the burner stoichiometric ratio of 0.75 is adopted, and the CO concentration at the outlet of the combustion chamber can be maintained simultaneously at a low level through the over-fired air injection of high velocity to enhance the mixing of the fresh air with the flue gas, which can provide the optimal solution for lower NOx Emission in the existing coal-fired boilers.
