微型流化床反应分析仪中煤半焦水蒸气气化反应特性

Steam gasification characteristics of coal char in micro-fluidized bed reaction analyzer

制备了在液氮中急速冷却和在氩气中自然冷却的两种半焦,采用扫描电镜(SEM)、N2吸附仪、红外光谱分析仪(FTIR)、X射线衍射仪(XRD)等方法系统比较了两种半焦的结构,并利用中国科学院过程工程研究所研发的微型流化床等温反应分析仪(MFBRA)研究包括动力学在内的水蒸气气化反应特性。研究发现:急速冷却半焦(Char-Q)具有更大的比表面积和更小的平均孔径,而自然冷却半焦(Char-S)的石墨化程度更高。在MFBRA中进行的气化反应结果揭示了Char-Q具有更快的反应速率。且比较通过等转化率法算出的活化能发现:Char-S水蒸气气化反应的活化能更大。利用MFBRA不仅求得了半焦水蒸气气化的总C转化的反应活化能(总体动力学),而且获得了生成各气体组分的反应(实际上为多个反应构成的体系)的活化能,实现了半焦水蒸气气化反应分析。因此,选择Char-Q作为分析试样更能反映真实热态半焦的气化行为,而MFBRA为深入研究涉及水蒸气参与的微分反应特性提供了有效的仪器与方法。

Two types of char were made through rapid quenching in liquid nitrogen （Char-Q） and natural cooling in argon （Char-S）. Systematic comparison was performed for the chars in terms of structure and gasification characteristics measured in the micro-fluidized bed reaction analyzer （MFBRA）, a well-proven isothermal reaction analyzer developed by Institute of Process Engineering, Chinese Academy of Sciences. Char-Q had the higher surface area but smaller average size of pores, while Char-S from slow cooling showed higher degree of graphitization. Gasification tests in MFBRA demonstrated that Char-Q had obviously higher reaction rate, and activation energy determined according to the iso-conversion method was higher for Char-S. Particularly, MFBRA enabled the determination of activation energy not only for the overall C conversion but also for the formation