混合气氛下褐煤热解特性的实验研究

Experimental research on lignite pyrolysis characteristics under mixed atmosphere

在模拟煤地下气化过程中气化剂参与状态的条件下,采用卧式干馏炉进行褐煤恒温热解,对乌兰察布褐煤在单一气氛(N_2、CO_2及H_2O)及混合气氛(CO_2/N_2、H_2O(g)/N_2)下的原煤热解特性进行研究,综合分析了温度和气氛对原煤热解特性的影响。研究结果表明:在单一和混合气氛下,热解气氛对半焦产率的影响较小,其变化趋势基本相似;热解气氛中的H_2O有利于焦油的生成;混合气氛下水产率一般要大于单气氛;对于煤气组分,当热解终温升高时,H_2浓度随着H_2O与C的还原反应速率的增大而不断升高,高达60%;升温有利于混合气氛下CH_4的析出和CO浓度的提高,分别达到22%和45%;对于烃类组分,单气氛下的烃类气体浓度大于混合气氛,这是由于混合气氛与热解产物进行化学反应,破坏了烃类分子结构。

Lignite pyrolysis experiments were carried out in constant temperature using horizontal dry distillation, under the condition of simulating state UCG gasification process with gasification agent, so as to study the pyrolysis characteristics of Ulanehap lignite in single （N2, CO2 or H2O） and mixed atmosphere （CO2/ N2, H2O （g） / N2 ）. Meanwhile, we comprehensively analyzed the influence of temperature and atmosphere on the pyrolysis characteristics. The results show that, under single and mixed atmosphere, pyrolysis atmosphere has little effect on carbocoal yield, the trend is similar; H2O is conducive to the formation of tar in pyrolysis atmosphere; water production rate under the mixed atmosphere is greater than single atmosphere ; for gas components, H2 concentration increases with the increase of reduction reaction rate of H2O and C when the final pyrolysis temperature rises, it can be as high as 60%. Increasing temperature is propitious to precipitation of cn4 and the increase of the concentration of CO, runs up to 22% and 45% respectively; for hydrocarbon components, the single atmosphere of hydrocarbon gas concentration is greater than the mixed atmosphere, this is due to the chemical reaction of mixed atmosphere and pyrolysis products, destroying the molecular structure of hydrocarbons.