The Experts below are selected from a list of 9480 Experts worldwide ranked by ideXlab platform
Zhiping Zhu - One of the best experts on this subject based on the ideXlab platform.
-
the effect of o2 c ratio on Gasification Performance and sodium transformation of zhundong coal
Fuel Processing Technology, 2019Co-Authors: Haixia Zhang, Xuewen Guo, Zhiping ZhuAbstract:Abstract The effect of O2/C ratio on Gasification Performance and sodium transformation behavior of a high‑sodium Zhundong coal was studied in a novel fluidized bed reactor. The sodium distribution was predicted through thermodynamic equilibrium calculation, and the possible reactions between sodium and other compounds were also discussed. The experimental results show that no agglomeration occurred in all cases. The carbon conversion and gas yield increase with the rise of O2/C ratio, while the cold gas efficiency has a maximum point (66.0%) at the O2/C molar ratio of 0.34. With the rise of the O2/C ratio, H2O-soluble sodium content and HCl-insoluble sodium content in fly ash and bottom char decrease, whereas HCl-soluble sodium content and CH3COONH4-soluble sodium content increase. Sodium presents mainly as NaAlSiO4, NaAlSi2O6 and Na2SO4 in bottom char, and as NaCl and NaAlSiO4 in fly ash. The equilibrium calculation results are coherent with the experimental study and can be used to predict the sodium transformation for the utilization of high sodium coal. The Si/Na ratio could affect the transformation of sodium significantly, and the agglomeration phenomenon could be reduced or avoided by inducing the formation of high melting point sodium-containing compounds through controlling the ratio of Si/Na.
-
The effect of O2/C ratio on Gasification Performance and sodium transformation of Zhundong coal
Fuel Processing Technology, 2019Co-Authors: Xuewen Guo, Haixia Zhang, Zhiping ZhuAbstract:Abstract The effect of O2/C ratio on Gasification Performance and sodium transformation behavior of a high‑sodium Zhundong coal was studied in a novel fluidized bed reactor. The sodium distribution was predicted through thermodynamic equilibrium calculation, and the possible reactions between sodium and other compounds were also discussed. The experimental results show that no agglomeration occurred in all cases. The carbon conversion and gas yield increase with the rise of O2/C ratio, while the cold gas efficiency has a maximum point (66.0%) at the O2/C molar ratio of 0.34. With the rise of the O2/C ratio, H2O-soluble sodium content and HCl-insoluble sodium content in fly ash and bottom char decrease, whereas HCl-soluble sodium content and CH3COONH4-soluble sodium content increase. Sodium presents mainly as NaAlSiO4, NaAlSi2O6 and Na2SO4 in bottom char, and as NaCl and NaAlSiO4 in fly ash. The equilibrium calculation results are coherent with the experimental study and can be used to predict the sodium transformation for the utilization of high sodium coal. The Si/Na ratio could affect the transformation of sodium significantly, and the agglomeration phenomenon could be reduced or avoided by inducing the formation of high melting point sodium-containing compounds through controlling the ratio of Si/Na.
-
effect of temperature on Gasification Performance and sodium transformation of zhundong coal
Fuel, 2017Co-Authors: Haixia Zhang, Xuewen Guo, Zhiping ZhuAbstract:Abstract The effect of temperature (between 850 °C and 1050 °C) on Gasification Performance and sodium transformation characteristics of a high-sodium Zhundong coal was investigated using a novel design of fluidized bed gasifier. The agglomeration tendency of Zhundong coal was predicted using the ternary phase diagram of Na2O-SiO2-Al2O3, and ways of inhibiting agglomeration were proposed. For the catalytic effect of sodium in coal ash, Zhundong coal shows good Gasification Performance; the concentration of CH4 is about 1% and changes slightly with an increase in temperature. Zhundong coal ash is located in the carnegieite (NaAlSiO4) region of the ternary phase diagram system, which is a high melting temperature zone where agglomeration does not easily occur. The sodium-containing compound detected in the 950 °C, 1000 °C, and 1050 °C bottom chars and fly ashes is NaAlSiO4. With increase in temperature, the sodium retention ratio first decreases but then increases. At higher temperature, more sodium is retained as NaAlSiO4 and therefore less is released. The enrichments of calcium and sodium on particle surface were observed by EDX analysis. The formed high melting point compounds of NaAlSiO4 and CaS may adhere to the surface of char particles and inhibit the release of sodium at higher temperature. Agglomeration and defluidization phenomena were not found in any experiment. The experimental results are in agreement with the prediction based on the ternary phase diagram analysis. Avoiding the use of silica as bed material, enhancing mixing and inducing the formation of the high melting point sodium-containing compound NaAlSiO4 are essential to inhibit agglomeration and defluidization. The experimental and thermodynamic calculation methods are useful in identifying conditions suitable for the successful use of high sodium coal during fluidized bed Gasification.
-
Circulating fluidized bed Gasification of low rank coal: Influence of O2/C molar ratio on Gasification Performance and sulphur transformation
Journal of Thermal Science, 2016Co-Authors: Haixia Zhang, Yukui Zhang, Zhiping ZhuAbstract:To promote the utilization efficiency of coal resources, and to assist with the control of sulphur during Gasification and/or downstream processes, it is essential to gain basic knowledge of sulphur transformation associated with Gasification Performance. In this research we investigated the influence of O2/C molar ratio both on Gasification Performance and sulphur transformation of a low rank coal, and the sulphur transformation mechanism was also discussed. Experiments were performed in a circulating fluidized bed gasifier with O2/C molar ratio ranging from 0.39 to 0.78 mol/mol. The results showed that increasing the O2/C molar ratio from 0.39 to 0.78 mol/mol can increase carbon conversion from 57.65% to 91.92%, and increase sulphur release ratio from 29.66% to 63.11%. The increase of O2/C molar ratio favors the formation of H2S, and also favors the retained sulphur transforming to more stable forms. Due to the reducing conditions of coal Gasification, H2S is the main form of the released sulphur, which could be formed by decomposition of pyrite and by secondary reactions. Bottom char shows lower sulphur content than fly ash, and mainly exist as sulphates. X-ray photoelectron spectroscopy (XPS) measurements also show that the intensity of pyrite declines and the intensity of sulphates increases for fly ash and bottom char, and the change is more obvious for bottom char. During CFB Gasification process, bigger char particles circulate in the system and have longer residence time for further reaction, which favors the release of sulphur species and can enhance the retained sulphur transforming to more stable forms.
Haixia Zhang - One of the best experts on this subject based on the ideXlab platform.
-
effect of coal blending on Gasification Performance and agglomeration
Energy & Fuels, 2020Co-Authors: Denghao Jiang, Haixia Zhang, Shengxian XianAbstract:To localize coal utilization, a local Hongshagang bituminous coal (Hc) with low ash fusion temperatures (AFTs) was blended with the Guanghui bituminous coal (Gc). Prior to its application in an ind...
-
the effect of o2 c ratio on Gasification Performance and sodium transformation of zhundong coal
Fuel Processing Technology, 2019Co-Authors: Haixia Zhang, Xuewen Guo, Zhiping ZhuAbstract:Abstract The effect of O2/C ratio on Gasification Performance and sodium transformation behavior of a high‑sodium Zhundong coal was studied in a novel fluidized bed reactor. The sodium distribution was predicted through thermodynamic equilibrium calculation, and the possible reactions between sodium and other compounds were also discussed. The experimental results show that no agglomeration occurred in all cases. The carbon conversion and gas yield increase with the rise of O2/C ratio, while the cold gas efficiency has a maximum point (66.0%) at the O2/C molar ratio of 0.34. With the rise of the O2/C ratio, H2O-soluble sodium content and HCl-insoluble sodium content in fly ash and bottom char decrease, whereas HCl-soluble sodium content and CH3COONH4-soluble sodium content increase. Sodium presents mainly as NaAlSiO4, NaAlSi2O6 and Na2SO4 in bottom char, and as NaCl and NaAlSiO4 in fly ash. The equilibrium calculation results are coherent with the experimental study and can be used to predict the sodium transformation for the utilization of high sodium coal. The Si/Na ratio could affect the transformation of sodium significantly, and the agglomeration phenomenon could be reduced or avoided by inducing the formation of high melting point sodium-containing compounds through controlling the ratio of Si/Na.
-
The effect of O2/C ratio on Gasification Performance and sodium transformation of Zhundong coal
Fuel Processing Technology, 2019Co-Authors: Xuewen Guo, Haixia Zhang, Zhiping ZhuAbstract:Abstract The effect of O2/C ratio on Gasification Performance and sodium transformation behavior of a high‑sodium Zhundong coal was studied in a novel fluidized bed reactor. The sodium distribution was predicted through thermodynamic equilibrium calculation, and the possible reactions between sodium and other compounds were also discussed. The experimental results show that no agglomeration occurred in all cases. The carbon conversion and gas yield increase with the rise of O2/C ratio, while the cold gas efficiency has a maximum point (66.0%) at the O2/C molar ratio of 0.34. With the rise of the O2/C ratio, H2O-soluble sodium content and HCl-insoluble sodium content in fly ash and bottom char decrease, whereas HCl-soluble sodium content and CH3COONH4-soluble sodium content increase. Sodium presents mainly as NaAlSiO4, NaAlSi2O6 and Na2SO4 in bottom char, and as NaCl and NaAlSiO4 in fly ash. The equilibrium calculation results are coherent with the experimental study and can be used to predict the sodium transformation for the utilization of high sodium coal. The Si/Na ratio could affect the transformation of sodium significantly, and the agglomeration phenomenon could be reduced or avoided by inducing the formation of high melting point sodium-containing compounds through controlling the ratio of Si/Na.
-
effect of temperature on Gasification Performance and sodium transformation of zhundong coal
Fuel, 2017Co-Authors: Haixia Zhang, Xuewen Guo, Zhiping ZhuAbstract:Abstract The effect of temperature (between 850 °C and 1050 °C) on Gasification Performance and sodium transformation characteristics of a high-sodium Zhundong coal was investigated using a novel design of fluidized bed gasifier. The agglomeration tendency of Zhundong coal was predicted using the ternary phase diagram of Na2O-SiO2-Al2O3, and ways of inhibiting agglomeration were proposed. For the catalytic effect of sodium in coal ash, Zhundong coal shows good Gasification Performance; the concentration of CH4 is about 1% and changes slightly with an increase in temperature. Zhundong coal ash is located in the carnegieite (NaAlSiO4) region of the ternary phase diagram system, which is a high melting temperature zone where agglomeration does not easily occur. The sodium-containing compound detected in the 950 °C, 1000 °C, and 1050 °C bottom chars and fly ashes is NaAlSiO4. With increase in temperature, the sodium retention ratio first decreases but then increases. At higher temperature, more sodium is retained as NaAlSiO4 and therefore less is released. The enrichments of calcium and sodium on particle surface were observed by EDX analysis. The formed high melting point compounds of NaAlSiO4 and CaS may adhere to the surface of char particles and inhibit the release of sodium at higher temperature. Agglomeration and defluidization phenomena were not found in any experiment. The experimental results are in agreement with the prediction based on the ternary phase diagram analysis. Avoiding the use of silica as bed material, enhancing mixing and inducing the formation of the high melting point sodium-containing compound NaAlSiO4 are essential to inhibit agglomeration and defluidization. The experimental and thermodynamic calculation methods are useful in identifying conditions suitable for the successful use of high sodium coal during fluidized bed Gasification.
-
circulating fluidized bed Gasification of low rank coal influence of o2 c molar ratio on Gasification Performance and sulphur transformation
Journal of Thermal Science, 2016Co-Authors: Haixia Zhang, Yukui Zhang, Qinggang LuAbstract:To promote the utilization efficiency of coal resources, and to assist with the control of sulphur during Gasification and/or downstream processes, it is essential to gain basic knowledge of sulphur transformation associated with Gasification Performance. In this research we investigated the influence of O2/C molar ratio both on Gasification Performance and sulphur transformation of a low rank coal, and the sulphur transformation mechanism was also discussed. Experiments were performed in a circulating fluidized bed gasifier with O2/C molar ratio ranging from 0.39 to 0.78 mol/mol. The results showed that increasing the O2/C molar ratio from 0.39 to 0.78 mol/mol can increase carbon conversion from 57.65% to 91.92%, and increase sulphur release ratio from 29.66% to 63.11%. The increase of O2/C molar ratio favors the formation of H2S, and also favors the retained sulphur transforming to more stable forms. Due to the reducing conditions of coal Gasification, H2S is the main form of the released sulphur, which could be formed by decomposition of pyrite and by secondary reactions. Bottom char shows lower sulphur content than fly ash, and mainly exist as sulphates. X-ray photoelectron spectroscopy (XPS) measurements also show that the intensity of pyrite declines and the intensity of sulphates increases for fly ash and bottom char, and the change is more obvious for bottom char. During CFB Gasification process, bigger char particles circulate in the system and have longer residence time for further reaction, which favors the release of sulphur species and can enhance the retained sulphur transforming to more stable forms.
Xuewen Guo - One of the best experts on this subject based on the ideXlab platform.
-
the effect of o2 c ratio on Gasification Performance and sodium transformation of zhundong coal
Fuel Processing Technology, 2019Co-Authors: Haixia Zhang, Xuewen Guo, Zhiping ZhuAbstract:Abstract The effect of O2/C ratio on Gasification Performance and sodium transformation behavior of a high‑sodium Zhundong coal was studied in a novel fluidized bed reactor. The sodium distribution was predicted through thermodynamic equilibrium calculation, and the possible reactions between sodium and other compounds were also discussed. The experimental results show that no agglomeration occurred in all cases. The carbon conversion and gas yield increase with the rise of O2/C ratio, while the cold gas efficiency has a maximum point (66.0%) at the O2/C molar ratio of 0.34. With the rise of the O2/C ratio, H2O-soluble sodium content and HCl-insoluble sodium content in fly ash and bottom char decrease, whereas HCl-soluble sodium content and CH3COONH4-soluble sodium content increase. Sodium presents mainly as NaAlSiO4, NaAlSi2O6 and Na2SO4 in bottom char, and as NaCl and NaAlSiO4 in fly ash. The equilibrium calculation results are coherent with the experimental study and can be used to predict the sodium transformation for the utilization of high sodium coal. The Si/Na ratio could affect the transformation of sodium significantly, and the agglomeration phenomenon could be reduced or avoided by inducing the formation of high melting point sodium-containing compounds through controlling the ratio of Si/Na.
-
The effect of O2/C ratio on Gasification Performance and sodium transformation of Zhundong coal
Fuel Processing Technology, 2019Co-Authors: Xuewen Guo, Haixia Zhang, Zhiping ZhuAbstract:Abstract The effect of O2/C ratio on Gasification Performance and sodium transformation behavior of a high‑sodium Zhundong coal was studied in a novel fluidized bed reactor. The sodium distribution was predicted through thermodynamic equilibrium calculation, and the possible reactions between sodium and other compounds were also discussed. The experimental results show that no agglomeration occurred in all cases. The carbon conversion and gas yield increase with the rise of O2/C ratio, while the cold gas efficiency has a maximum point (66.0%) at the O2/C molar ratio of 0.34. With the rise of the O2/C ratio, H2O-soluble sodium content and HCl-insoluble sodium content in fly ash and bottom char decrease, whereas HCl-soluble sodium content and CH3COONH4-soluble sodium content increase. Sodium presents mainly as NaAlSiO4, NaAlSi2O6 and Na2SO4 in bottom char, and as NaCl and NaAlSiO4 in fly ash. The equilibrium calculation results are coherent with the experimental study and can be used to predict the sodium transformation for the utilization of high sodium coal. The Si/Na ratio could affect the transformation of sodium significantly, and the agglomeration phenomenon could be reduced or avoided by inducing the formation of high melting point sodium-containing compounds through controlling the ratio of Si/Na.
-
effect of temperature on Gasification Performance and sodium transformation of zhundong coal
Fuel, 2017Co-Authors: Haixia Zhang, Xuewen Guo, Zhiping ZhuAbstract:Abstract The effect of temperature (between 850 °C and 1050 °C) on Gasification Performance and sodium transformation characteristics of a high-sodium Zhundong coal was investigated using a novel design of fluidized bed gasifier. The agglomeration tendency of Zhundong coal was predicted using the ternary phase diagram of Na2O-SiO2-Al2O3, and ways of inhibiting agglomeration were proposed. For the catalytic effect of sodium in coal ash, Zhundong coal shows good Gasification Performance; the concentration of CH4 is about 1% and changes slightly with an increase in temperature. Zhundong coal ash is located in the carnegieite (NaAlSiO4) region of the ternary phase diagram system, which is a high melting temperature zone where agglomeration does not easily occur. The sodium-containing compound detected in the 950 °C, 1000 °C, and 1050 °C bottom chars and fly ashes is NaAlSiO4. With increase in temperature, the sodium retention ratio first decreases but then increases. At higher temperature, more sodium is retained as NaAlSiO4 and therefore less is released. The enrichments of calcium and sodium on particle surface were observed by EDX analysis. The formed high melting point compounds of NaAlSiO4 and CaS may adhere to the surface of char particles and inhibit the release of sodium at higher temperature. Agglomeration and defluidization phenomena were not found in any experiment. The experimental results are in agreement with the prediction based on the ternary phase diagram analysis. Avoiding the use of silica as bed material, enhancing mixing and inducing the formation of the high melting point sodium-containing compound NaAlSiO4 are essential to inhibit agglomeration and defluidization. The experimental and thermodynamic calculation methods are useful in identifying conditions suitable for the successful use of high sodium coal during fluidized bed Gasification.
Siyi Luo - One of the best experts on this subject based on the ideXlab platform.
-
influence of particle size on pyrolysis and Gasification Performance of municipal solid waste in a fixed bed reactor
Bioresource Technology, 2010Co-Authors: Siyi Luo, Bo Xiao, Shiming Liu, Yanwen Guan, Lei CaiAbstract:Abstract Pyrolysis and Gasification of municipal solid waste (MSW) were carried out in a lab-scale fixed bed reactor in order to evaluate the effects of particle size at different bed temperatures on product yield and composition. The bed temperature was varied from 600 to 900 °C and the MSW was separated into three different size fractions (below 5 mm, 50–10 mm and above 10 mm). Particle size and temperature had integrated effects on product yield and composition: higher temperature resulted in higher gas yield with less tar and char, and, at the same temperature, dry gas yield increased with a decrease in particle size, and char and tar yield decreased. The differences due to particle sizes in pyrolysis and Gasification Performance practically disappeared at the highest temperatures tested. Smaller particle sizes resulted in higher H 2 and CO contents for both pyrolysis and Gasification of MSW. Minimizing the size of raw materials is an alternative method to improve the gas quality of MSW pyrolysis and Gasification.
-
hydrogen rich gas from catalytic steam Gasification of biomass in a fixed bed reactor influence of temperature and steam on Gasification Performance
International Journal of Hydrogen Energy, 2009Co-Authors: Siyi Luo, Bo Xiao, Shiming Liu, Xianjun GuoAbstract:The catalytic steam Gasification of biomass was carried out in a lab-scale fixed bed reactor in order to evaluate the effects of temperatures and the ratio of steam to biomass (S/B) on the Gasification Performance. The bed temperature was varied from 600 to 900 and the S/B from 0 to 2.80. The results show that higher temperature contributes to more hydrogen production. The introduction of steam improves the dry gas yield and carbon conversion efficiency. But excessive steam will lower hydrogen content and degrade fuel gas quality. As S/B are 2.10, the hydrogen content reach the maximum, up to 52.7%.
-
hydrogen rich gas from catalytic steam Gasification of biomass in a fixed bed reactor influence of particle size on Gasification Performance
International Journal of Hydrogen Energy, 2009Co-Authors: Siyi Luo, Bo Xiao, Xianjun Guo, Zhiquan Hu, Shiming Liu, Maoyun HeAbstract:Abstract The catalytic steam Gasification of biomass was carried out in a lab-scale fixed bed reactor in order to evaluate the effects of particle size at different bed temperatures on the Gasification Performance. The bed temperature was varied from 600 to 900 °C and the biomass was separated into five different size fractions (below 0.075 mm, 0.075–0.15 mm, 0.15–0.3 mm, 0.3–0.6 mm and 0.6–1.2 mm). The results show that with decreasing particle size, the dry gas yield, carbon conversion efficiency and H2 yield increased, and the content of char and tar decreased. And the differences due to particle sizes in Gasification Performance practically disappear as the higher temperature bound is approached. Hydrogen and carbon monoxide contents in the produced gas increase with decreasing particle size at 900 °C, reaching to 51.2% and 22.4%, respectively.
Tatsuya Kodama - One of the best experts on this subject based on the ideXlab platform.
-
steam Gasification of coal cokes by internally circulating fluidized bed reactor by concentrated xe light radiation for solar syngas production
Energy, 2015Co-Authors: Nobuyuki Gokon, Takuya Izawa, Tatsuya KodamaAbstract:A laboratory-scale prototype windowed reactor using a fluidized bed of coal coke particles was tested for thermochemical Gasification using concentrated Xe light radiation as an energy source. The fluidized-bed reactor, designed to be combined with a solar reflective tower or beam-down optics, is evaluated for steam Gasification of coal coke according to Gasification Performance: CO, H2, and CO2 production rates; carbon conversion; light-to-chemical efficiency. Internal circulation of coal coke particles inside the reactor increases Gasification Performance, which is further enhanced by higher steam partial pressure of the inlet gas.
-
co2 Gasification of coal cokes using internally circulating fluidized bed reactor by concentrated xe light irradiation for solar Gasification
International Journal of Hydrogen Energy, 2012Co-Authors: Nobuyuki Gokon, Ryuta Ono, Tsuyoshi Hatamachi, L I Liuyun, Heejoon Kim, Tatsuya KodamaAbstract:Abstract For the solar thermochemical Gasification of coal coke to produce CO + H2 synthetic gas using concentrated solar radiation, a windowed reactor prototype is tested and demonstrated at laboratory scale for CO2 Gasification of coal coke using concentrated Xe light from a 3-kWth sun simulator. The reactor was designed to be combined with a solar reflective tower or beam-down optics. The results for Gasification Performance (CO production rate, carbon conversion, and light-to-chemical efficiency) are shown for various CO2 flow rates and ratios. A kinetics analysis based on homogeneous and shrinking core models and the temperature distributions of the prototype particle bed are compared with those for a conventional fluidized bed reactor tested under the same Xe light irradiation and CO2 flow-rate conditions. The effectiveness and potential impacts of internally circulating fluidized bed reactors for enhancing Gasification Performance levels and inducing consistently higher bed temperatures are discussed in this paper.