CIESC Journal

• 化工学报 • 上一篇    下一篇

煤焦的水蒸汽气化反应速率解析

金革,杨宝田,屈雪如,刘桂芬   

  1. 沈阳化工学院化学工程系 ,沈阳化工学院化学工程系 ,沈阳化工学院化学工程系 ,沈阳化工学院化学工程系
  • 出版日期:1987-06-25 发布日期:1987-06-25

Analysis of Reaction Rate of Coal Char Gasified with Steam

Chin Ge, Yang Baotian, Qu Xueru and Liu Guifen (Shen Yang institute of Chemical Engineering)   

  • Online:1987-06-25 Published:1987-06-25

摘要: 为得到煤的气化技术开发的基础数据,在固定床微分反应器中,于常压、动力学控制条件下,对国内外七种煤半焦进行水蒸汽气化实验.将煤的气化反应速率用水蒸汽分压及煤的未转化率的幂函数型式表示时,其结果是与水蒸汽分压及细孔表面积的一次方成正比.从理论上推导出了在反应过程中包括考虑煤的细孔结构变化的动力学方程,并且导出了含碳组分气体的生成速率与煤的气化速率的相关式.用Bhatia等人的随机细孔模型表示反应过程中的细孔表面积变化时,计算结果与实测值相当吻合.

Abstract: Seven different samples of coal chars were gasified with steam in a fixed-bed differential reactor, operating under atmospheric pressure. A generalized kinetic equation for the gasification of coal char with steam was established. Such basic data obtained might be found useful in gasification furnace design work as well as in gasification technology. The initial gasification rate of coal char could be expressed as: (1) The relationship between char conversion x and the rate canstant was found to be: Changes in specific surface area of pores could be obtained from the random pore model introduced by Bhatia and Perimutter: (3) where was a characteristic physical parameter of coal Putting Eq. (3) into Eq. (1), the generalized rate expression becamedx/dt =KS0PH2o(1 - x) ( 4 ) Integrating Eq. (4) with x = 0 at t = 0, char conversion at any period ought be. x = 1 - exp[ - K S0PH2ot (1 + b/4K S0PH2ot) ( 5 ) Using Eq. (4) rate canstant K could be evaluted from the observed initial gasification rate(dx/dt)x=0 such as (6) Putting K thus obtained at any specific reaction temperature into Eq. (5), char conversion at any desired interval might be predicted. Calculated values correlated rather satisfactorily experimental results obtained. Further studies revealed that the production rate of carbon-borne gases related to the overall gasification rate of coal in the following manner: (7)