A novel micro kinetic analyzer(MFBK) for fluidized bed gas-solid reactions is developed.With this MFBK analyzer,the reaction rate and kinetic parameters can be deduced via measuring the time-dependent composition chan...A novel micro kinetic analyzer(MFBK) for fluidized bed gas-solid reactions is developed.With this MFBK analyzer,the reaction rate and kinetic parameters can be deduced via measuring the time-dependent composition changes of its evolved gas.By using a micro fluidized bed reactor,it is expected to enable the on-line feed of particle reactant based on a pulse solid conveying mechanics and the effective suppression of external gas diffusion in the reactor.This MFBK analyzer is evaluated through the decomposition of CaCO3 powder,giving an apparent activation energy of 142.73 kJ·mol-1 and a preexponential factor of 399777 s-1.This activation energy value is much lower then the TG-measured one of 184.3 kJ·mol-1 and within the literature-reported range of 120—280 kJ·mol-1.The measurement also provides a kinetic-model function with a correlation linearity of above 0.99.With this MFBK analyzer,the pyrolysis of coal and biomass at 800℃ is studied.The measured pyrolysis reaction finished in about 15 s,which is very close to the theoretically anticipation.This pyrolysis measurement with the MFBK analyzer can also identify a definite gas release order for typical gas species contained in the pyrolysis-formed gas products,which actually can provide a strong evidence for the deep insight in the pyrolysis reaction mechanism.展开更多
在概述最新研发的微型流化床反应分析(micro-fluidized bed reaction analysis,MFBRA)方法与应用的基础上,应用该方法进一步研究了半焦-CO2、半焦-水蒸气等温气化反应动力学,并与热重分析(thermogravimet-ric analyzer,TGA)求取的气化...在概述最新研发的微型流化床反应分析(micro-fluidized bed reaction analysis,MFBRA)方法与应用的基础上,应用该方法进一步研究了半焦-CO2、半焦-水蒸气等温气化反应动力学,并与热重分析(thermogravimet-ric analyzer,TGA)求取的气化反应动力学数据比较。在最小化气体扩散的实验条件下,利用MFBRA和TGA测定求算的半焦-CO2、半焦-水蒸气气化反应在受反应动力学控制的低温段的活化能非常接近,说明了MFBRA对等温气化反应分析的适用性和可靠性。实验研究还发现:半焦-CO2、半焦-水蒸气气化反应在MFBRA中受反应动力学控制的温度范围较在TGA中明显宽,且在具有明显扩散影响的高温段通过MFBRA测定的半焦-CO2气化反应表观活化能明显大于利用TGA测定的值,表明在MFBRA中受到的气体扩散抑制效应较小。展开更多
利用新开发的微型流化床反应分析仪(micro-fluidized bed reaction analysis,MFBRA)考察了义马烟煤半焦的原位以及两种非原位半焦气化行为并测定了其动力学参数,其中,原位半焦气化是指煤热解温度和气氛与半焦气化过程一致,非原位半焦1...利用新开发的微型流化床反应分析仪(micro-fluidized bed reaction analysis,MFBRA)考察了义马烟煤半焦的原位以及两种非原位半焦气化行为并测定了其动力学参数,其中,原位半焦气化是指煤热解温度和气氛与半焦气化过程一致,非原位半焦1气化是指煤在Ar气氛下热解,热态条件下直接在CO2气氛下气化;非原位半焦2气化是指煤在Ar气氛下热解,冷却收集后再在CO2气氛下气化。研究发现,原位半焦具有最大的比表面积和最小的平均孔径,石墨化程度最弱,且对CO2的化学吸附能力最强,表面活性位点最多。在最小化气体扩散的实验条件下,原位半焦气化反应的反应速率明显比非原位半焦气化反应快,且求取的活化能数据较小。实验揭示了原位半焦和非原位半焦结构和反应性的差异,也证明了MFBRA对原位等温气化反应的适用性。展开更多
文摘A novel micro kinetic analyzer(MFBK) for fluidized bed gas-solid reactions is developed.With this MFBK analyzer,the reaction rate and kinetic parameters can be deduced via measuring the time-dependent composition changes of its evolved gas.By using a micro fluidized bed reactor,it is expected to enable the on-line feed of particle reactant based on a pulse solid conveying mechanics and the effective suppression of external gas diffusion in the reactor.This MFBK analyzer is evaluated through the decomposition of CaCO3 powder,giving an apparent activation energy of 142.73 kJ·mol-1 and a preexponential factor of 399777 s-1.This activation energy value is much lower then the TG-measured one of 184.3 kJ·mol-1 and within the literature-reported range of 120—280 kJ·mol-1.The measurement also provides a kinetic-model function with a correlation linearity of above 0.99.With this MFBK analyzer,the pyrolysis of coal and biomass at 800℃ is studied.The measured pyrolysis reaction finished in about 15 s,which is very close to the theoretically anticipation.This pyrolysis measurement with the MFBK analyzer can also identify a definite gas release order for typical gas species contained in the pyrolysis-formed gas products,which actually can provide a strong evidence for the deep insight in the pyrolysis reaction mechanism.
文摘在概述最新研发的微型流化床反应分析(micro-fluidized bed reaction analysis,MFBRA)方法与应用的基础上,应用该方法进一步研究了半焦-CO2、半焦-水蒸气等温气化反应动力学,并与热重分析(thermogravimet-ric analyzer,TGA)求取的气化反应动力学数据比较。在最小化气体扩散的实验条件下,利用MFBRA和TGA测定求算的半焦-CO2、半焦-水蒸气气化反应在受反应动力学控制的低温段的活化能非常接近,说明了MFBRA对等温气化反应分析的适用性和可靠性。实验研究还发现:半焦-CO2、半焦-水蒸气气化反应在MFBRA中受反应动力学控制的温度范围较在TGA中明显宽,且在具有明显扩散影响的高温段通过MFBRA测定的半焦-CO2气化反应表观活化能明显大于利用TGA测定的值,表明在MFBRA中受到的气体扩散抑制效应较小。
文摘利用新开发的微型流化床反应分析仪(micro-fluidized bed reaction analysis,MFBRA)考察了义马烟煤半焦的原位以及两种非原位半焦气化行为并测定了其动力学参数,其中,原位半焦气化是指煤热解温度和气氛与半焦气化过程一致,非原位半焦1气化是指煤在Ar气氛下热解,热态条件下直接在CO2气氛下气化;非原位半焦2气化是指煤在Ar气氛下热解,冷却收集后再在CO2气氛下气化。研究发现,原位半焦具有最大的比表面积和最小的平均孔径,石墨化程度最弱,且对CO2的化学吸附能力最强,表面活性位点最多。在最小化气体扩散的实验条件下,原位半焦气化反应的反应速率明显比非原位半焦气化反应快,且求取的活化能数据较小。实验揭示了原位半焦和非原位半焦结构和反应性的差异,也证明了MFBRA对原位等温气化反应的适用性。
