Modeling study on the external heated entrained flow reactor in Shengli lignite mild gasification process:Solution and application

The solution process and application of the one dimensional entrained flow bed gasification model proposed early were studied. It was found that the predicted values were in good agreement with the experimental values,with the error of less than 20% for 92% predicted values and less than 10% for 75% predicted values,which indicated proper dynamic equations and solving method for obtaining the values of unknown parameters were chosen. The model could also be used to predict well the gasification process under different temperature,atmosphere,residence time and particle diameter. The prediction results showed that,firstly,as the residence time increased,lignite conversion,H2 & CO2 content increased sharply and then slowly,CO content increased and then decreased,especially under high steam concentration and temperature. Secondly,ignite burning time is less than 0. 5 seconds in 1% O2 atmosphere at 800 ℃ , significantly less than the gasification time,which proved the suppose that gasification process occurred after combustion process was reasonable. Thirdly,the sum content of CO,H2 in large size lignite gasification gas was higher than that in small size lignite gasification gas,which was consistent with the experimental results and may caused by the mi- cro structure of different diameter char. Lastly,for initial carbon content of lignite particles in unit volume ( Γ),gas solid effective contact ( collision) area in unit volume ( Λ),CO and CO2 partition coefficient in combustion process (α),sensitivities of coal conversion to them were at the same level,while sensitivities of the sum content of CO,H2 in gas to them were different significantly with the order from strong to weak,as α,Λ,Γ.