微型流化床反应分析及其对煤焦气化动力学的应用

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(thermogravimetric 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。

Micro fluidized bed reaction analysis and its application to coal char gasification kinetics

After summarizing the newly developed micro-fluidized bed reaction analysis (MFBRA) and its existing applications, its application to the kinetics of isothermal gasification reaction between coal char and CO₂/steam were further extended.The resulting kinetic data were compared with the measurements in thermogravimetric analyzer (TGA).Under minimized limitations of heat and mass transfer, the activation energy of char gasification with CO₂ and steam in the kinetically controlled low temperature region was very close to that obtained from TGA, validating the reliability of MFBRA for the analysis of char gasification kinetics.Moreover, the temperature range of the kinetically controlled reaction region was found to be obviously wider in MFBRA than in TGA for both char-CO₂ and char-steam reactions.At higher temperatures with evident limitations of heat and mass transfer on the reaction kinetics, the estimated activation energy was obviously higher with MFBRA than that with TGA.All of these further demonstrated that the diffusion limitation in MFBRA was weaker than that in TGA for gasification of coal char.