Effect Of KOH On Carbon Crystallite Structure And Gasification Reactivity Of Coal And Petroleum

Shenfu coal,Jincheng coal and NingboZhongjin petroleum coke loading with KOH were pyrolyzed by high-frequency furnace.The effects of pyrolysis temperature,K content and residence time on graphitization structure and gasification reactivity of chars were studied.The main contents and results were summarized as follows:(1)Fast pyrolysis results of coal and petroleum showed that the effect of KOH on mass loss of Shenfu coal and Jincheng coal is irregular,while K increases the mass loss of petroleum coke.With the increass of temperature the degree of carbon crystallite structure order and graphitization gets deeper for Shenfu coal while it gets lower for Jingcheng coal.The later stage of pyrolysis chars of Shenfu coal and Jincheng coal have deeper graphitization degree than earlier stage of pyrolysis chars while it differs for petroleum coke.K addition reduces the degree of carbon crystallite structure and the effect gets more significant with higher K Content.The increase of pyrolysis temperature and the addition of KOH could inhibit the graphitization progress of petroleum coke and decrease the crystallite stacking height.(2)The gasification reactivity of chars were investigated via TGA.The results showed that the addition of KOH increased gasification rate and improved gasification reactivity.With the increase of pyrolysis temperature,char gasification reactivity of Shenfu coal increased first and then decreased,reactivity of Jincheng coal remained the same,petroleum coke reactivity increased with the increasing of pyrolysis temperature.The reactivity of fast pyrolysis chars of earlier stage pyrolysis were better than that of later stage.Catalytic pyrolysis chars of Shenfu coal with K were washed by ammonium acetate solution to find that gasification reactivity of chars with different K content was well correlated to the crystallite structure,and effect of K on pyrolysis could also contribute to the subsequent gasification reaction.The modified random pore model had good fitting result on the catalytic gasification data.