压力对煤气化反应的影响

为了提高煤气化效率,分析了影响产能的重要因素——压力。研究了压力对煤热解过程、煤焦燃烧速度及煤焦气化反应的影响。研究发现:加压热解情况下,挥发分和焦油产率均下降,但煤气产量增加,推测是因为焦油发生二次反应造成的。随着压力的增大,煤焦明显膨胀且比表面积下降。但过高的压力下,膨胀度减弱,易生成孔隙率高、薄壁的煤焦颗粒。提高O2分压,煤燃烧速度加快且生成的小颗粒较多。提高气化剂分压,煤气化速度加快,且蒸汽分解速度大于CO2还原速度,但生成的煤气对气化反应有抑制作用。

Influence of pressure on coal gasification

Analyzed the influence of pressure,the key factor,on coal gasification in order to increase the reaction efficiency.Mainly studied the effects of pressure on coal pyrolysis,burning velocity of coke and coke gasification.The results show that yield of volatile matter and tar both decrease,as opposite to gas,whose yield increases while increasing pressure.That can be explained that tar starts secondary reaction.As pressure increasing,coke expand apparently and its specific surface area decrease.When the pressure is too high,degree of expansion decrease slowly and tend to form high porosity and thin wall thickness coal char particles.That increasing oxygen partial pressure could accelerate burning velocity and form more fine coal particles.Gasification rate increases with the increase of partical pressure of gasification agent.The deposition rate of H2O is lower than the reduction rate of CO2,whereas generated gas could further pervent the gasification reaction.