生物质焦的水蒸气汽化动力学研究

Steam gasification kinetics of biomass char

生物质汽化包括生物质的热解及随后的生物质焦的水蒸气汽化过程。为了给生物质汽化反应器的设计提供基础数据,利用热天平试验装置对1273K制备的生物质焦行了水蒸气汽化反应性试验,研究了汽化温度对汽化反应性、平均比汽化速率、反应速率等的影响。并且利用均相模型和缩芯模型拟合试验数据求得了相应的动力学参数。得出结论:随着温度的增加,焦炭汽化反应性增加,平均比汽化速率增加。由均相模型所算得活化能为181.24kJ/mol,指前因子为5.19×105min-1,缩芯模型所算得活化能为192.87kJ/mol,指前因子为1.60×106min-1。在转化率为10%～75%范围内,均相模型和缩芯模型均可以很好的描述生物质焦的水蒸气汽化行为,但是缩芯模型比均相模型的拟合效果要好。

Biomass gasification includes biomass pyrolysis and steam gasification of biomass chars subsequently.In order to provide basic data for the design of biomass gasification reactor,thermal balance was used to finish steam gasification of biomass char,which was produced at 1273K.Effects of the gasification temperature on the gasification reactivity,the average gasification rate,and the reaction rate were investigated.And the homogeneous model and shrinking core model were employed to obtain the corresponding kinetic parameters.With the increasing temperature,biomass steam gasification reactivity and the average rate increased.The activity energy was 181.24 kJ/mol,the pre-exponential factor was 5.19×105 min-1 with homogeneous model.The activity energy was 192.87 kJ/mol,pre-exponential factor was 1.60×106 min-1 with shrinking core model.Both shrinking core model and homogeneous model can describe the process of biomass char steam gasification well,however,shrinking core model fit the experimental data better than homogeneous model.