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Jun Xiao - One of the best experts on this subject based on the ideXlab platform.
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effect of temperature on reduction of caso4 oxygen carrier in chemical looping combustion of simulated Coal Gas in a fluidized bed reactor
Industrial & Engineering Chemistry Research, 2008Co-Authors: Qilei Song, Rui Xiao, Laihong Shen, Zhongyi Deng, Jun Xiao, Mingyao ZhangAbstract:Chemical-looping combustion (CLC) is a promising combustion technology for Gaseous and solid fuel with efficient use of energy and inherent separation of CO2. The concept of a Coal-fueled CLC system using calcium sulfate (CaSO4) as oxygen carrier is proposed in this study. Reduction tests of CaSO4 oxygen carrier with simulated Coal Gas were performed in a laboratory-scale fluidized bed reactor in the temperature range of 890−950 °C. A high concentration of CO2 was obtained at the initial reduction period. CaSO4 oxygen carrier exhibited high reactivity initially and decreased gradually at the late period of reduction. The sulfur release during the reduction of CaSO4 as oxygen carrier was also observed and analyzed. H2 and CO conversions were greatly influenced by reduction temperature. The carbon deposition ratio was found to be quite low. The oxygen carrier conversion and mass-based reaction rates during the reduction at typical temperatures were compared. Higher temperatures would enhance reaction rates ...
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multicycle study on chemical looping combustion of simulated Coal Gas with a caso4 oxygen carrier in a fluidized bed reactor
Energy & Fuels, 2008Co-Authors: Qilei Song, Rui Xiao, Laihong Shen, Zhongyi Deng, Wenguang Zheng, Jun XiaoAbstract:Chemical-looping combustion (CLC) is a promising technology for the combustion of Gas and solid fuel with efficient use of energy and inherent separation of CO2. In this study, the cyclic test of a CaSO4-based oxygen carrier (natural anhydrite) in alternating reducing simulated Coal Gas and oxidizing conditions was performed at 950 °C in a fluidized bed reactor at atmospheric pressure. A high concentration of CO2 was obtained in the reduction. The H2 and CO conversions and CO2 yield increased initially and final decreased significantly. The release of SO2 and H2S during the cyclic test was found to be responsible for the decrease of reactivity of a CaSO4 oxygen carrier. The oxygen carrier conversion after the reduction reaction decreased gradually in the cyclic test. Through the comparison of mass-based reaction rates as a function of mass conversion at typical cycles, it was also evident that the reactivity of a CaSO4 oxygen carrier increased for the initial cycles but finally decreased after around 15 c...
Qilei Song - One of the best experts on this subject based on the ideXlab platform.
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effect of temperature on reduction of caso4 oxygen carrier in chemical looping combustion of simulated Coal Gas in a fluidized bed reactor
Industrial & Engineering Chemistry Research, 2008Co-Authors: Qilei Song, Rui Xiao, Laihong Shen, Zhongyi Deng, Jun Xiao, Mingyao ZhangAbstract:Chemical-looping combustion (CLC) is a promising combustion technology for Gaseous and solid fuel with efficient use of energy and inherent separation of CO2. The concept of a Coal-fueled CLC system using calcium sulfate (CaSO4) as oxygen carrier is proposed in this study. Reduction tests of CaSO4 oxygen carrier with simulated Coal Gas were performed in a laboratory-scale fluidized bed reactor in the temperature range of 890−950 °C. A high concentration of CO2 was obtained at the initial reduction period. CaSO4 oxygen carrier exhibited high reactivity initially and decreased gradually at the late period of reduction. The sulfur release during the reduction of CaSO4 as oxygen carrier was also observed and analyzed. H2 and CO conversions were greatly influenced by reduction temperature. The carbon deposition ratio was found to be quite low. The oxygen carrier conversion and mass-based reaction rates during the reduction at typical temperatures were compared. Higher temperatures would enhance reaction rates ...
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multicycle study on chemical looping combustion of simulated Coal Gas with a caso4 oxygen carrier in a fluidized bed reactor
Energy & Fuels, 2008Co-Authors: Qilei Song, Rui Xiao, Laihong Shen, Zhongyi Deng, Wenguang Zheng, Jun XiaoAbstract:Chemical-looping combustion (CLC) is a promising technology for the combustion of Gas and solid fuel with efficient use of energy and inherent separation of CO2. In this study, the cyclic test of a CaSO4-based oxygen carrier (natural anhydrite) in alternating reducing simulated Coal Gas and oxidizing conditions was performed at 950 °C in a fluidized bed reactor at atmospheric pressure. A high concentration of CO2 was obtained in the reduction. The H2 and CO conversions and CO2 yield increased initially and final decreased significantly. The release of SO2 and H2S during the cyclic test was found to be responsible for the decrease of reactivity of a CaSO4 oxygen carrier. The oxygen carrier conversion after the reduction reaction decreased gradually in the cyclic test. Through the comparison of mass-based reaction rates as a function of mass conversion at typical cycles, it was also evident that the reactivity of a CaSO4 oxygen carrier increased for the initial cycles but finally decreased after around 15 c...
Mingyao Zhang - One of the best experts on this subject based on the ideXlab platform.
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Equilibrium Analyses of H2S Conversion during Hot Gas Desulfurization
2010 4th International Conference on Bioinformatics and Biomedical Engineering, 2010Co-Authors: Zhanlong Song, Mingyao ZhangAbstract:The complexity of the Coal Gas compositions and their reactions properties affect the sulfidation of H2S with calcium-based-based sorbents, which is not easy to measure quantificationally. Using the ASPEN PLUS software, the reaction degrees between Coal Gas compositions can be obtained easily. The results show that the thermal decomposition of H2S is affected by temperature greatly and the higher the temperature, the less stable H2S is. Adding the H2 composite will increase the stability of H2S. When the H2 molar content is higher than 2.5 %, the H2S hardly dissociate. The higher the pressure, the less of H2S decomposes. CO2 and CO both can react with H2S resulting to the decrease of H2S equilibrium concentration. The water-Gas-shift reaction is the most important one among the Coal Gas reactions. If H2 and CO2 are present in the reaction Gas, CO and H2O will appear in the off-Gas largely and hence the CO and H2O compound can not be introduced to the Gaseous mixtures on the experiment of H2S with calcium-based sorbents to some extent.
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effect of temperature on reduction of caso4 oxygen carrier in chemical looping combustion of simulated Coal Gas in a fluidized bed reactor
Industrial & Engineering Chemistry Research, 2008Co-Authors: Qilei Song, Rui Xiao, Laihong Shen, Zhongyi Deng, Jun Xiao, Mingyao ZhangAbstract:Chemical-looping combustion (CLC) is a promising combustion technology for Gaseous and solid fuel with efficient use of energy and inherent separation of CO2. The concept of a Coal-fueled CLC system using calcium sulfate (CaSO4) as oxygen carrier is proposed in this study. Reduction tests of CaSO4 oxygen carrier with simulated Coal Gas were performed in a laboratory-scale fluidized bed reactor in the temperature range of 890−950 °C. A high concentration of CO2 was obtained at the initial reduction period. CaSO4 oxygen carrier exhibited high reactivity initially and decreased gradually at the late period of reduction. The sulfur release during the reduction of CaSO4 as oxygen carrier was also observed and analyzed. H2 and CO conversions were greatly influenced by reduction temperature. The carbon deposition ratio was found to be quite low. The oxygen carrier conversion and mass-based reaction rates during the reduction at typical temperatures were compared. Higher temperatures would enhance reaction rates ...
Shujun Zhu - One of the best experts on this subject based on the ideXlab platform.
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effects of secondary air velocity on no emission with Coal preheating technology
Fuel, 2019Co-Authors: Wen Liu, Ziqu Ouyang, Xiaoyang Cao, Daofeng Liu, Shujun ZhuAbstract:Abstract This study investigated experimentally the effects of the injection velocity of the secondary air on combustion and NO emissions of Shenmu semi-coke in a 30 kW Coal preheating combustion test rig. Results showed that the self-preheating burner could provide with the high temperature preheated fuel (Coal Gas and Coal char) stably and continuously without extra heat input. Most of volatile-N was released following with the release of volatiles during the preheating process, which was conductive to inhibit NO formation. The combustion temperatures were uniform in the down-fire-combustor and flame images were all dark red with no obvious flame fronts. The Coal Gas was rapidly consumed in the upper part while the Coal char was burnt out in the lower part of the down-fire-chamber. The presence of two combustion zones would contribute to leading to more uniform temperatures. Char-N was the main source of NO in the research, and NO was reduced by the Coal Gas (CO, CHi, NHi and other species) and char simultaneously above 1000 mm. While below 1000 mm, char was dominating for NO reduction. In the paper, the relationship of injection velocity of secondary air and exit NOx emissions was not clearly revealed. It was believed that the effects of secondary air velocity were multifactorial. Mean temperature and root mean square temperature were associated with the exit NOx emissions. When mean temperature and root mean square temperature are low, the exit NOx emissions are low correspondingly.
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preheating combustion characteristics of ultra low volatile carbon based fuel
Journal of Thermal Science, 2019Co-Authors: Shujun Zhu, Qinggang Lyu, Jianguo Zhu, Chengbo Man, Wen LiuAbstract:Pulverized Coal combustion technology with preheating solid fuel in a circulating fluidized bed was used for the combustion test of ultra-low volatile carbon-based fuel. This paper first validated the feasibility and advantages of applying the combustion technology to this kind of fuel. The carbon-based fuel could achieve a stable preheating process in this test system. After the preheating, the apparent sensible heat of the fuel was significantly increased. This provided a necessary condition for the stable ignition and efficient combustion of the carbon-based fuel in the post-combustion chamber. The relative proportions of CO, H2, and CH4 in preheated Coal Gas were very low, and the effect of high-temperature Coal Gas at the entrance of the post-combustion chamber was greatly impaired, indicating that the combustion process in post-combustion chamber was mainly the combustion of preheated char. At the same time, the strong reducing atmosphere in the circulating fluidized bed also facilitated the reduction of fuel-nitrogen into N2, which resulted in low NOx emissions. On this basis, with the combination of preheating combustion technology and air-staging combustion technology, the NOx emissions had drastically decreased when the burnout air distribution position moved down or varied from a single-layer distribution to a multi-layer distribution system. The lowest original NOx emissions were 90.6 mg/m3 (at 6% O2), and the combustion efficiency exceeded 97%, which ultimately achieved efficient and clean combustion of ultra-low volatile carbon-based fuel.
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no emissions under pulverized char mild combustion in o2 co2 preheated by a circulating fluidized bed effect of oxygen staging Gas distribution
Fuel Processing Technology, 2018Co-Authors: Shujun Zhu, Qinggang Lyu, Jianguo ZhuAbstract:Abstract MILD (moderate or intense low-oxygen dilution) combustion of pulverized char in O2/CO2 was achieved by preheating fuel in a circulating fluidized bed (CFB). The purpose of this research was to study effects of oxygen-staging Gas distribution on NO emissions under MILD combustion of pulverized char. First, the preheating characteristics were evaluated, including the conversion ratios of each fuel component and the composition of the Coal Gas. To calculate the nitrogen balance in the preheating process, the Gas in the loop seal was changed to O2/N2. The results indicate that the conversion ratios of each component increased with the increasing oxygen concentration in the primary Gas, and the conversion ratio of nitrogen was above 0.40. In addition, the reduced proportion of nitrogen increased with the increase of oxygen concentrations in the primary Gas, surpassing 30.0%. The heating value of high-temperature Coal Gas also increased. Next, the effects of oxygen-staging Gas distribution on NO emissions were investigated. Increasing oxygen concentrations in the primary Gas and in the secondary Gas as well as decreasing oxygen concentration in the tertiary Gas all reduced NO emissions. The lowest NO emission was 26.8 mg/MJ, and the combustion efficiency was above 99.0%. These results demonstrate that the oxy-fuel preheating combustion technology with effective oxygen-staging Gas distribution could achieve clean, efficient combustion of pulverized char.
Rui Xiao - One of the best experts on this subject based on the ideXlab platform.
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effect of temperature on reduction of caso4 oxygen carrier in chemical looping combustion of simulated Coal Gas in a fluidized bed reactor
Industrial & Engineering Chemistry Research, 2008Co-Authors: Qilei Song, Rui Xiao, Laihong Shen, Zhongyi Deng, Jun Xiao, Mingyao ZhangAbstract:Chemical-looping combustion (CLC) is a promising combustion technology for Gaseous and solid fuel with efficient use of energy and inherent separation of CO2. The concept of a Coal-fueled CLC system using calcium sulfate (CaSO4) as oxygen carrier is proposed in this study. Reduction tests of CaSO4 oxygen carrier with simulated Coal Gas were performed in a laboratory-scale fluidized bed reactor in the temperature range of 890−950 °C. A high concentration of CO2 was obtained at the initial reduction period. CaSO4 oxygen carrier exhibited high reactivity initially and decreased gradually at the late period of reduction. The sulfur release during the reduction of CaSO4 as oxygen carrier was also observed and analyzed. H2 and CO conversions were greatly influenced by reduction temperature. The carbon deposition ratio was found to be quite low. The oxygen carrier conversion and mass-based reaction rates during the reduction at typical temperatures were compared. Higher temperatures would enhance reaction rates ...
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multicycle study on chemical looping combustion of simulated Coal Gas with a caso4 oxygen carrier in a fluidized bed reactor
Energy & Fuels, 2008Co-Authors: Qilei Song, Rui Xiao, Laihong Shen, Zhongyi Deng, Wenguang Zheng, Jun XiaoAbstract:Chemical-looping combustion (CLC) is a promising technology for the combustion of Gas and solid fuel with efficient use of energy and inherent separation of CO2. In this study, the cyclic test of a CaSO4-based oxygen carrier (natural anhydrite) in alternating reducing simulated Coal Gas and oxidizing conditions was performed at 950 °C in a fluidized bed reactor at atmospheric pressure. A high concentration of CO2 was obtained in the reduction. The H2 and CO conversions and CO2 yield increased initially and final decreased significantly. The release of SO2 and H2S during the cyclic test was found to be responsible for the decrease of reactivity of a CaSO4 oxygen carrier. The oxygen carrier conversion after the reduction reaction decreased gradually in the cyclic test. Through the comparison of mass-based reaction rates as a function of mass conversion at typical cycles, it was also evident that the reactivity of a CaSO4 oxygen carrier increased for the initial cycles but finally decreased after around 15 c...