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Yijun Zhao - One of the best experts on this subject based on the ideXlab platform.

  • characteristics of gas liquid solid products in corn straw gasification effect of the char tar h2o interaction
    Energy & Fuels, 2019
    Co-Authors: Dongdong Feng, Yijun Zhao
    Abstract:

    The characteristics of gas–liquid–solid products during corn straw–H2O gasification were studied by the one-stage fluidized-bed/fixed-bed quartz reactor. The results indicate that the transformation between gas and solid products is mainly presented with the increase of feeding time (0–40 min). The aromaticity of biochar decreases slightly in the feeding period of 10–20 min but gradually increases in 20–40 min. The oxygen-containing functional groups in biochar increase gradually with the increase of the feeding time. The K content in biochar increases by 27% in 10–30 min, while that of Ca increases by 36% in 10–20 min. When the Carbon Conversion Rate is less than 8%, the reactivity of biochar produced by 30 min of feeding is highest. The contents of phenol and 2,3-dihydrobenzofuran of tar increase by 25 and 34%, respectively in 20–40 min. The char–tar–H2O interaction in biomass gasification is a two-stage reaction. The first stage is dominated by the volatile–char interactions, while the second stage is ...

  • Characteristics of Gas–Liquid–Solid Products in Corn Straw Gasification: Effect of the Char–Tar–H2O Interaction
    Energy & Fuels, 2019
    Co-Authors: Hongliang Sun, Yijun Zhao, Dongdong Feng, Dawei Guo, Heping Tan, Shaozeng Sun
    Abstract:

    The characteristics of gas–liquid–solid products during corn straw–H2O gasification were studied by the one-stage fluidized-bed/fixed-bed quartz reactor. The results indicate that the transformation between gas and solid products is mainly presented with the increase of feeding time (0–40 min). The aromaticity of biochar decreases slightly in the feeding period of 10–20 min but gradually increases in 20–40 min. The oxygen-containing functional groups in biochar increase gradually with the increase of the feeding time. The K content in biochar increases by 27% in 10–30 min, while that of Ca increases by 36% in 10–20 min. When the Carbon Conversion Rate is less than 8%, the reactivity of biochar produced by 30 min of feeding is highest. The contents of phenol and 2,3-dihydrobenzofuran of tar increase by 25 and 34%, respectively in 20–40 min. The char–tar–H2O interaction in biomass gasification is a two-stage reaction. The first stage is dominated by the volatile–char interactions, while the second stage is ...

  • Kinetic characteristics of in-situ char-steam gasification following pyrolysis of a demineralized coal
    International Journal of Hydrogen Energy, 2018
    Co-Authors: Yijun Zhao, Shaozeng Sun, Wenda Zhang, Pengxiang Wang, Peng Liu, Guang Zeng, Shu Zhang
    Abstract:

    Abstract This study aims to examine the char-steam reactions in-situ, following the pyrolysis process of a demineralized coal in a micro fluidized bed reactor, with particular focuses on gas release and its kinetics characteristics. The main experimental variables were temperatures (925 °C−1075 °C) and steam concentrations (15%–35% H2O), and the combination of pyrolysis and subsequent gasification in one experiment was achieved switching the atmosphere from pure argon to steam and argon mixture. The results indicate that when temperature was higher than 975 °C, the absolute Carbon Conversion Rate during the char gasification could easily reach 100%. When temperature was 1025 °C and 1075 °C, the Carbon Conversion Rate changed little with steam concentration increasing from 25% to 35%. The activation energy calculated from shrinking core model and random pore model was all between 186 and 194 kJ/mol, and the fitting accuracy of shrinking core model was higher than that of the random pore model in this study. The char reactivity from demineralized coal pyrolysis gradually worsened with decreasing temperature and steam partial pressure. The range of reaction order of steam gasification was 0.49–0.61. Compared to raw coal, the progress of water gas shift reaction (CO + H2O ↔ CO2 + H2) was hindered during the steam gasification of char obtained from the demineralized coal pyrolysis. Meanwhile, the gas content from the char gasification after the demineralized coal pyrolysis showed a low sensitivity to the change in temperature.

  • Experimental Study on Autothermal Cyclone Air Gasification of Biomass
    Journal of Energy Resources Technology, 2017
    Co-Authors: Yijun Zhao, Dongdong Feng, Zhibo Zhang, Shaozeng Sun, Hongwei Che, Jiyi Luan
    Abstract:

    Cyclone gasification technology is commonly used for biomass fuels with small particle sizes, such as rice husks and wood chips. This paper explored the effects of gasification intensity and equivalence ratio on the performance characteristics of an autothermal cyclone gasifier. Increasing the gasification intensity caused the syngas' heating value, the cold gasification efficiency and the Carbon Conversion Rate to increase to a maximum for an intensity of 885.24 kg/(m2 h) before then decreasing as the gasification intensity was further increased. Increasing the equivalence ratio from 0.23 to 0.32 increased the overall temperature of gasifier, decreased the tar content (from 6.84 to 4.96 g/N·m3), and increased the Carbon Conversion Rate (from 47.2% to 62.3%). Increasing the equivalence ratio to 0.26 also increased the syngas' heating value to its maximum of 4.25 MJ/N·m3, which then decreased with further increases in equivalence ratio. A similar trend was observed for the gasification efficiency, which ranged from 30% to 37%. From these tests, a gasification intensity of 885.24 kg/(m2 h) and an equivalence ratio of 0.26 appeared optimal for the autothermal cyclone air gasification of biomass process studied here.

  • Experimental study of cyclone pyrolysis - Suspended combustion air gasification of biomass.
    Bioresource technology, 2017
    Co-Authors: Yijun Zhao, Dongdong Feng, Zhibo Zhang, Shaozeng Sun, Xinwei Zhou, Jiyi Luan
    Abstract:

    Abstract Based on the original biomass cyclone gasifier, the cyclone pyrolysis-suspension combustion gasification technology was constituted with a bottom wind ring to build the biochar suspension combustion zone. This technology decouples the biomass pyrolysis, gasification (reduction reaction) and combustion (oxidation reaction) within the same device. With the feed amount and total air fixed, the effect of air Rate arrangement on temperature distribution of the gasifier, syngas components and gasification parameters was studied. With the secondary air Rate (0.20) and bottom air Rate (0.50), the gasification efficiency was best, with gas heating value of 5.15 MJ/Nm 3 , Carbon Conversion Rate of 71.50%, gasification efficiency of 50.80% and syngas yield of 1.29 Nm 3 /kg. The device with biochar for the tar catalytic cracking was installed at the gasifier outlet, effectively reducing the tar content in syngas, with a minimum value of 1.02 g/Nm 3 .

Shaozeng Sun - One of the best experts on this subject based on the ideXlab platform.

  • Characteristics of Gas–Liquid–Solid Products in Corn Straw Gasification: Effect of the Char–Tar–H2O Interaction
    Energy & Fuels, 2019
    Co-Authors: Hongliang Sun, Yijun Zhao, Dongdong Feng, Dawei Guo, Heping Tan, Shaozeng Sun
    Abstract:

    The characteristics of gas–liquid–solid products during corn straw–H2O gasification were studied by the one-stage fluidized-bed/fixed-bed quartz reactor. The results indicate that the transformation between gas and solid products is mainly presented with the increase of feeding time (0–40 min). The aromaticity of biochar decreases slightly in the feeding period of 10–20 min but gradually increases in 20–40 min. The oxygen-containing functional groups in biochar increase gradually with the increase of the feeding time. The K content in biochar increases by 27% in 10–30 min, while that of Ca increases by 36% in 10–20 min. When the Carbon Conversion Rate is less than 8%, the reactivity of biochar produced by 30 min of feeding is highest. The contents of phenol and 2,3-dihydrobenzofuran of tar increase by 25 and 34%, respectively in 20–40 min. The char–tar–H2O interaction in biomass gasification is a two-stage reaction. The first stage is dominated by the volatile–char interactions, while the second stage is ...

  • Kinetic characteristics of in-situ char-steam gasification following pyrolysis of a demineralized coal
    International Journal of Hydrogen Energy, 2018
    Co-Authors: Yijun Zhao, Shaozeng Sun, Wenda Zhang, Pengxiang Wang, Peng Liu, Guang Zeng, Shu Zhang
    Abstract:

    Abstract This study aims to examine the char-steam reactions in-situ, following the pyrolysis process of a demineralized coal in a micro fluidized bed reactor, with particular focuses on gas release and its kinetics characteristics. The main experimental variables were temperatures (925 °C−1075 °C) and steam concentrations (15%–35% H2O), and the combination of pyrolysis and subsequent gasification in one experiment was achieved switching the atmosphere from pure argon to steam and argon mixture. The results indicate that when temperature was higher than 975 °C, the absolute Carbon Conversion Rate during the char gasification could easily reach 100%. When temperature was 1025 °C and 1075 °C, the Carbon Conversion Rate changed little with steam concentration increasing from 25% to 35%. The activation energy calculated from shrinking core model and random pore model was all between 186 and 194 kJ/mol, and the fitting accuracy of shrinking core model was higher than that of the random pore model in this study. The char reactivity from demineralized coal pyrolysis gradually worsened with decreasing temperature and steam partial pressure. The range of reaction order of steam gasification was 0.49–0.61. Compared to raw coal, the progress of water gas shift reaction (CO + H2O ↔ CO2 + H2) was hindered during the steam gasification of char obtained from the demineralized coal pyrolysis. Meanwhile, the gas content from the char gasification after the demineralized coal pyrolysis showed a low sensitivity to the change in temperature.

  • Experimental Study on Autothermal Cyclone Air Gasification of Biomass
    Journal of Energy Resources Technology, 2017
    Co-Authors: Yijun Zhao, Dongdong Feng, Zhibo Zhang, Shaozeng Sun, Hongwei Che, Jiyi Luan
    Abstract:

    Cyclone gasification technology is commonly used for biomass fuels with small particle sizes, such as rice husks and wood chips. This paper explored the effects of gasification intensity and equivalence ratio on the performance characteristics of an autothermal cyclone gasifier. Increasing the gasification intensity caused the syngas' heating value, the cold gasification efficiency and the Carbon Conversion Rate to increase to a maximum for an intensity of 885.24 kg/(m2 h) before then decreasing as the gasification intensity was further increased. Increasing the equivalence ratio from 0.23 to 0.32 increased the overall temperature of gasifier, decreased the tar content (from 6.84 to 4.96 g/N·m3), and increased the Carbon Conversion Rate (from 47.2% to 62.3%). Increasing the equivalence ratio to 0.26 also increased the syngas' heating value to its maximum of 4.25 MJ/N·m3, which then decreased with further increases in equivalence ratio. A similar trend was observed for the gasification efficiency, which ranged from 30% to 37%. From these tests, a gasification intensity of 885.24 kg/(m2 h) and an equivalence ratio of 0.26 appeared optimal for the autothermal cyclone air gasification of biomass process studied here.

  • Experimental study of cyclone pyrolysis - Suspended combustion air gasification of biomass.
    Bioresource technology, 2017
    Co-Authors: Yijun Zhao, Dongdong Feng, Zhibo Zhang, Shaozeng Sun, Xinwei Zhou, Jiyi Luan
    Abstract:

    Abstract Based on the original biomass cyclone gasifier, the cyclone pyrolysis-suspension combustion gasification technology was constituted with a bottom wind ring to build the biochar suspension combustion zone. This technology decouples the biomass pyrolysis, gasification (reduction reaction) and combustion (oxidation reaction) within the same device. With the feed amount and total air fixed, the effect of air Rate arrangement on temperature distribution of the gasifier, syngas components and gasification parameters was studied. With the secondary air Rate (0.20) and bottom air Rate (0.50), the gasification efficiency was best, with gas heating value of 5.15 MJ/Nm 3 , Carbon Conversion Rate of 71.50%, gasification efficiency of 50.80% and syngas yield of 1.29 Nm 3 /kg. The device with biochar for the tar catalytic cracking was installed at the gasifier outlet, effectively reducing the tar content in syngas, with a minimum value of 1.02 g/Nm 3 .

Dongdong Feng - One of the best experts on this subject based on the ideXlab platform.

  • characteristics of gas liquid solid products in corn straw gasification effect of the char tar h2o interaction
    Energy & Fuels, 2019
    Co-Authors: Dongdong Feng, Yijun Zhao
    Abstract:

    The characteristics of gas–liquid–solid products during corn straw–H2O gasification were studied by the one-stage fluidized-bed/fixed-bed quartz reactor. The results indicate that the transformation between gas and solid products is mainly presented with the increase of feeding time (0–40 min). The aromaticity of biochar decreases slightly in the feeding period of 10–20 min but gradually increases in 20–40 min. The oxygen-containing functional groups in biochar increase gradually with the increase of the feeding time. The K content in biochar increases by 27% in 10–30 min, while that of Ca increases by 36% in 10–20 min. When the Carbon Conversion Rate is less than 8%, the reactivity of biochar produced by 30 min of feeding is highest. The contents of phenol and 2,3-dihydrobenzofuran of tar increase by 25 and 34%, respectively in 20–40 min. The char–tar–H2O interaction in biomass gasification is a two-stage reaction. The first stage is dominated by the volatile–char interactions, while the second stage is ...

  • Characteristics of Gas–Liquid–Solid Products in Corn Straw Gasification: Effect of the Char–Tar–H2O Interaction
    Energy & Fuels, 2019
    Co-Authors: Hongliang Sun, Yijun Zhao, Dongdong Feng, Dawei Guo, Heping Tan, Shaozeng Sun
    Abstract:

    The characteristics of gas–liquid–solid products during corn straw–H2O gasification were studied by the one-stage fluidized-bed/fixed-bed quartz reactor. The results indicate that the transformation between gas and solid products is mainly presented with the increase of feeding time (0–40 min). The aromaticity of biochar decreases slightly in the feeding period of 10–20 min but gradually increases in 20–40 min. The oxygen-containing functional groups in biochar increase gradually with the increase of the feeding time. The K content in biochar increases by 27% in 10–30 min, while that of Ca increases by 36% in 10–20 min. When the Carbon Conversion Rate is less than 8%, the reactivity of biochar produced by 30 min of feeding is highest. The contents of phenol and 2,3-dihydrobenzofuran of tar increase by 25 and 34%, respectively in 20–40 min. The char–tar–H2O interaction in biomass gasification is a two-stage reaction. The first stage is dominated by the volatile–char interactions, while the second stage is ...

  • Experimental Study on Autothermal Cyclone Air Gasification of Biomass
    Journal of Energy Resources Technology, 2017
    Co-Authors: Yijun Zhao, Dongdong Feng, Zhibo Zhang, Shaozeng Sun, Hongwei Che, Jiyi Luan
    Abstract:

    Cyclone gasification technology is commonly used for biomass fuels with small particle sizes, such as rice husks and wood chips. This paper explored the effects of gasification intensity and equivalence ratio on the performance characteristics of an autothermal cyclone gasifier. Increasing the gasification intensity caused the syngas' heating value, the cold gasification efficiency and the Carbon Conversion Rate to increase to a maximum for an intensity of 885.24 kg/(m2 h) before then decreasing as the gasification intensity was further increased. Increasing the equivalence ratio from 0.23 to 0.32 increased the overall temperature of gasifier, decreased the tar content (from 6.84 to 4.96 g/N·m3), and increased the Carbon Conversion Rate (from 47.2% to 62.3%). Increasing the equivalence ratio to 0.26 also increased the syngas' heating value to its maximum of 4.25 MJ/N·m3, which then decreased with further increases in equivalence ratio. A similar trend was observed for the gasification efficiency, which ranged from 30% to 37%. From these tests, a gasification intensity of 885.24 kg/(m2 h) and an equivalence ratio of 0.26 appeared optimal for the autothermal cyclone air gasification of biomass process studied here.

  • Experimental study of cyclone pyrolysis - Suspended combustion air gasification of biomass.
    Bioresource technology, 2017
    Co-Authors: Yijun Zhao, Dongdong Feng, Zhibo Zhang, Shaozeng Sun, Xinwei Zhou, Jiyi Luan
    Abstract:

    Abstract Based on the original biomass cyclone gasifier, the cyclone pyrolysis-suspension combustion gasification technology was constituted with a bottom wind ring to build the biochar suspension combustion zone. This technology decouples the biomass pyrolysis, gasification (reduction reaction) and combustion (oxidation reaction) within the same device. With the feed amount and total air fixed, the effect of air Rate arrangement on temperature distribution of the gasifier, syngas components and gasification parameters was studied. With the secondary air Rate (0.20) and bottom air Rate (0.50), the gasification efficiency was best, with gas heating value of 5.15 MJ/Nm 3 , Carbon Conversion Rate of 71.50%, gasification efficiency of 50.80% and syngas yield of 1.29 Nm 3 /kg. The device with biochar for the tar catalytic cracking was installed at the gasifier outlet, effectively reducing the tar content in syngas, with a minimum value of 1.02 g/Nm 3 .

Hongliang Sun - One of the best experts on this subject based on the ideXlab platform.

  • Characteristics of Gas–Liquid–Solid Products in Corn Straw Gasification: Effect of the Char–Tar–H2O Interaction
    Energy & Fuels, 2019
    Co-Authors: Hongliang Sun, Yijun Zhao, Dongdong Feng, Dawei Guo, Heping Tan, Shaozeng Sun
    Abstract:

    The characteristics of gas–liquid–solid products during corn straw–H2O gasification were studied by the one-stage fluidized-bed/fixed-bed quartz reactor. The results indicate that the transformation between gas and solid products is mainly presented with the increase of feeding time (0–40 min). The aromaticity of biochar decreases slightly in the feeding period of 10–20 min but gradually increases in 20–40 min. The oxygen-containing functional groups in biochar increase gradually with the increase of the feeding time. The K content in biochar increases by 27% in 10–30 min, while that of Ca increases by 36% in 10–20 min. When the Carbon Conversion Rate is less than 8%, the reactivity of biochar produced by 30 min of feeding is highest. The contents of phenol and 2,3-dihydrobenzofuran of tar increase by 25 and 34%, respectively in 20–40 min. The char–tar–H2O interaction in biomass gasification is a two-stage reaction. The first stage is dominated by the volatile–char interactions, while the second stage is ...

Chang H. Cho - One of the best experts on this subject based on the ideXlab platform.

  • High-Efficiency Gasification of Low-Grade Coal by Microwave Steam Plasma
    Energy & Fuels, 2014
    Co-Authors: Han S. Uhm, Yong Cheol Hong, Dong H. Shin, Chang H. Cho, Young Ki Park
    Abstract:

    High-power steam plasma for heating the coal powders were developed, where the magnetron power at 915 MHz was available up to 75 kW. The steam plasma itself is an impedance load, which depends on physical conditions, including the microwave power. By monitoring the minimum reflected power, the optimum injection Rate of the steam and the corresponding reflected power ratio in terms of the microwave power was found, showing that most of the microwave power is absorbed by the torch plasma with a minimal reflected wave-power of less than a few percent, once the plasma torch was ignited. Indonesian brown coal with high ash content is gasified by two microwave steam plasmas heating up the gas temperature in a reaction chamber of 1145 L in a swirl-type gasifier. With additional heating of synthetic gas from a partial oxidation, the inner temperature of the gasifier can reach to 1700 °C. The Carbon Conversion Rate at the average chamber temperature of 1640 °C is almost 100%, ensuring a complete gasification of ca...

  • Production of hydrogen-rich synthetic gas from low-grade coals by microwave steam-plasmas
    International Journal of Hydrogen Energy, 2014
    Co-Authors: Han S. Uhm, Yong Cheol Hong, Dong H. Shin, Chang H. Cho
    Abstract:

    Abstract Indonesian brown-coal with high ash-content is gasified by two microwave steam-plasmas heating up the gas temperature in a reaction chamber of 1145 l in a swirl-type gasifier for production of hydrogen-rich synthetic gas. With additional heating of synthetic gas by a partial oxidation of coal, the inner temperature of the gasifier can reach to 1700 °C. The Carbon Conversion Rate at the chamber temperature of 1640 °C is almost 100 percent, ensuring a complete gasification of Carbons in a low-grade coal. The cold gas efficiency of the hydrogen-rich synthetic gas is 84%, very high in a relatively-small gasifier like the experiment here. The total calorific value of the synthetic gas is 500 kW.