Study On Grinding Behavior And Gasification Characteristics Of Coal Blending High-sulfur Petroleum Coke

The grindability index(HGI) and size distribution of two typical high-sulfur petroleum cokes, two coal samples and their blends were studied by ball mill, HGI analyzer and laser particle analyzer. The relationship between HGI of coal/petroleum coke blends and petroleum coke proportion in the mixture was investigated. And the relationship between HGI and particle size distribution was analyzed qualitatively. Gasification characteristics and gasification kinetics of coal,petroleum coke and coal blending petroleum coke with different ratios were explored by using temperature programmed thermogravimetric method and constant temperature method respectively. The co-gasification synergy of coal and petroleum coke were discussed. The main conclusions were summarized as follows:1) Different kinds of petroleum coke have different HGI. The HGI of shot coke (MM,32.73) is far less than sponge coke (MG,74.13). The HGI of ZX coal and LY coal are66.86and73.97respectively. The HGI of coal/petroleum coke mixture samples can be improved with the content of coal whose HGI is much higher than petroleum coke increase. The HGI of coal/petroleum coke mixture samples and petroleum coke proportion in the mixture show a good linear relationship when their HGI have large difference (△HGI>30). The HGI of coal/petroleum coke mixture samples and petroleum coke proportion in the mixture show a poor linear relationship when their HGI are almost equal or slightly different. There isn’t direct proportion relationship between HGI and particle size in MG. Although the HGI of MG is almost equal with LY and even greater than ZX, its particle size is greater than LY and ZX at the same grinding conditions. The particle size distribution of coal/petroleum coke mixture samples are all inclined to particle size distribution of coal.2) XRD, FTIR and thermogravimetric analysis showed that, microcrystalline structure of petroleum coke tends to be graphitization. The initial gasification temperature and terminated temperature of two coals are far lower than that of the two kinds of petroleum coke, reactivity index is greater than petroleum coke. The reactive order is:ZX> LY>MM>MG.3) The research results of temperature programmed thermogravimetric method and constant temperature method showed that, blending ZX or LY can significantly reduce initial gasification temperature, terminated temperature and improve reactivity index of MM and MG.4) The homogeneous model and shrinking nucleus model for constant temperature gasification kinetics calculation results showed that, two models can adapt to the gasification process of the coal, petroleum coke and coal/petroleum coke mixture samples. The reaction rate constant k calculated by homogeneous model is higher than that of shrinking core model. The reaction rate constant of petroleum coke can be improved in different degrees by blending ZX or LY. Temperature programmed gasification kinetics calculation showed that, reaction activation energy of MM and MG are higher than LY and ZX, blending ZX or LY coal can reduce their gasification reaction activation energy.5) The experimental value of carbon conversion is almost all higher than the calculated value in different coal/petroleum coke mixture samples at a certain temperature. It concluded that there was a synergetic effect between coal and petroleum coke during co-gasification process. ZX coal ash played a catalytic gasification role in the co-gasification of coal and petroleum coke. This could be the main reason for co-gasification of coal and petroleum coke exist synergy.