微型流化床反应分析仪中原位/非原位煤焦气化动力学研究

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。

Investigation on in/ex-situ coal char gasification kinetics in a micro fluidized bed reactor

In-situ char and ex-situ char gasification characteristic was studied by using a newly developed micro fluidized bed reaction analyzer (MFBRA) and the reaction kinetics parameters were obtained. The in-situ char gasification proceeds using the same atmosphere, temperature and reactor in the gasification following the pyrolysis; the ex-situ char 1 gasification is defined as coal pyrolysis in Ar atmosphere and then gasification at hot state in the same reactor; and ex-situ char 2 gasification reaction is defined as coal pyrolysis in Ar atmosphere and then gasification after thermal annealing. By analyzing the three kinds of char, it can be seen that in-situ char has the largest specific surface area, lowest graphitization degree, and strongest sorption ability for CO₂. Under the minimized limitations of heat and mass transfer, in-situ char gasification has the highest reaction rate, and lowest reaction energy. The study also proves the reliability of MFBRA for in-situ char gasification reaction.