Study On Co-gasification Characteristics And Kinetics Of Corn Stalks And Jincheng Anthracite

Gasification is considered to be an effective way for biomass thermal energy conversion.However,there are some defects in biomass gasification alone,low energy density and high tar content etc.The co-gasification of coal and biomass can form complementary advantages,which has practical value for the utilization of biomass energy and theoretical significance.This paper selects corn stalks,Jincheng anthracite as experimental raw materials.Co-pyrolysis,CO₂ non-isothermal and isothermal co-gasification of corn stalks,Jincheng anthracite and Jincheng Anthracite treated by HF-HCl acid-washing were studied in a thermogravimetric analyzer,and taking the demineralized anthracite char supported by K₂CO₃ and CaO catalysts as research objects,the effects of K and Ca in ash on the gasification process were invested.On the basis of the above experiments,the kinetics of co-pyrolysis and co-gasification of raw materials was calculated.The main conclusions are as follows:Jincheng anthracite ash removal rate reached 99%using HF-HCl acid-washing method,then the specific surface area increased from 8.766 m²/g to 14.034 m²/g,and the BJH theoretical results suggested the type of pores would not change.Non-isothermal co-gasification of corn stalks with Jincheng anthracite and demineralized anthracite in proportion of 0%,2%,5%,and 9%,respectively.It indicate that the co-gasification reaction temperature of corn stalks and demineralized anthracite lags behind that of corn stalks and raw coal,and the peak value of the maximum weight loss rate is higher than that of corn stalks and raw coal during the co-gasification stage.It may be due to the catalysis of ash in Jincheng anthracite resulted in advancing the gasification reaction,while the acid-washing treatment of Jincheng anthracite improved relatively pore structure,the gasification agent has more reactive active sites,thus the gasification reaction rate increases and the value of weight loss rate is large.Isothermal gasification experiments of chars generated from the pyrolysis of corn stalks and anthracite also show that the mix-char co-gasification of demineralized coal and corn stalks has higher reactivity.K₂CO₃ and CaO catalysts were respectively loaded in the proportion of 1%,3%and 5%in the demineralized anthracite char for isothermal gasification experiment,and the gasification reactivity index R_0.5 and R_0.9 were used to measure the gasification reactivity of the char.The results showed that the reactivity of coal char gasification with catalyst is higher than that of coal char gasification alone under any load,and the gasification reactivity of the char with K₂CO₃ catalyst was higher than that of the char with CaO catalyst.The kinetics of co-pyrolysis and non-isothermal co-gasification of corn stalks and coal were calculated by single reaction model and N-level reaction model,respectively.The activation energy of co-pyrolysis of corn stalks blended with Jincheng Anthracite is lower than that of corn stalks blended with demineralized Anthracite,and the activation energy of non-isothermal gasification of corn stalks and raw coal is lower than that of corn stalks blended with demineralized Anthracite.The results show that there is a certain synergistic effect between corn stalks and a small amount of Jincheng Anthracite during the reaction of co-pyrolysis and co-gasification.The synergy largely related to the catalytic action of alkali metal and alkaline earth metal in Jincheng Anthracite ash.The activation energy of isothermal gasification fitted by DAEM model increased first and then decreased with the increase of carbon conversion.There are 19 figures,16 tables and 78 references in this paper.