Study On Gasification Reactivity Of Coal Char Effected By Corn Straw Ash

With the adjustment of energy structure and the decline of coal resources, coal gasification technology has drawn great attention among people. For the sake of improving gasification efficiency and lowering temperature of gasification, a lot of studies about char catalytic gasification have been conducted. Corn straw, as a kind of renewable energy, is rich in alkali metals during the process of growth. If we can make full use of these abundant alkali metals, the corn straw could become a cheap catalytic source of coal char gasification.In this thesis, catalytic effect and influence rule of corn straw ash as a catalyst for coal char catalytic gasification were studied. The effect of coal ash, different pyrolytic conditions and the time of corn straw ash added on gasification reactivity of coal char were investigated in this paper. Through using the Raman, iodine adsorption value and CO2 strong chemisorption value, the changes in physical and chemical properties of chars catalyzed by corn straw were also analyzed.During the coking process, corn straw ash decreased the ordering of chars, increased the number of micro-pores and the specific surface areas were also increased; The added corn straw ash also promoted the formation of catalytic active sites, increased the value of CO2 strong chemisorption.There showed no obvious synergies during coking between corn straw and coal, and owing to the catalytic effect of alkali metal contained in corn straw, a significant increase of co-coking chars reactivity was displayed; The added corn straw ash can evidently enhance the reactivity of chars gasification, and when the impregnated loadings of ash were same, corn straw ash showed a better catalytic effect in the case where the catalysts were impregnated to the coal before preparing chars in comparison to impregnating catalysts to raw char.The coal ash showed some inhibition in the catalytic effect of corn straw ash, and with the specific surface area of chars varied, the optimum loading of corn straw ash also changed.There existed an optimum coking temperature and at which time the prepared raw coal char showed a best reactivity; With the residence time increased, the reactivity of the raw coal char made in high pyrolytic temperature decreased and of the char made in low pyrolytic temperature increased; At different coking conditions, the corn straw ash all showed some promotion in char reactivity, but when this condition became harsh, this promotion became weak gradually.Kinetic parameters of some catalytic gasification of coal char were computed simply, and the parameters conformed to the experiment conclusion well.