Experimental Study Of Pore Structure Characteristics And Gasification Reaction Of Semi-coke

As high energy consumption, high pollution industries, saving energy and improving the economic benefit is the only way for enterprise survival and development. As a kind of indispensable raw material in blast furnace ironmaking, coke has been one of the main factors of high steelmaking cost because of its expensive. In order to reduce the costs and improve economic efficiency, it is urgent to find alternative coke alternative fuel. Due to Semi-coke’s good reactivity and low price, similar physical and chemical properties, it can be used to replace coke research. In the massive and soft melting zone of blast furnace, Melting reaction would inevitably occur, which can reduce the strength, bring the deterioration of blast furnace condition, increase the coke rate and costs; This article wants to make semi-coke to replace the coke which is lost due to the melting reaction in soft melting zone, in order to reduce coke rate and improve the economic benefit.The pore structure, pore surface area, pore volume and other physical and chemical properties of semi-coke and coke were studied by using mercury intrusion method and low temperature nitrogen adsorption method. The results show that internal pore structure network of semi-coke and coke show "ink bottle" shape or the hair of mixed structure. The macropore and mesopore volume determine two char pore volume size, The micropore pore surface area determine the size of two coal pore surface area. The pore surface area and total pore volume of semi coke are 5 times and 2 times as many as that of coke, it fully indicates that the pore structure of semi coke is more developed than that of coke.The paper analysis the influence on semi-coke and coke gasification reaction of different size, CO₂ gas flow and the speed of heating rates using STA449F3 thermogravimetric analyzer, the results show that: the particle size is smaller, the gasification reaction temperature is lower, reaction rate is faster. Semi-coke weightlessness is higher than coke, particle size has a little influence on the reactivity of semi-coke and coke. Gasification process of semi-coke is divided into two stages, which are precipitation of volatile and fixed carbon gasification. Coke only has fixed carbon gasification process, temperature of precipitation of volatile is not affected by changes in the experimental condition, it is determined by its own nature, the precipitation rate is maximum when temperature is at about 900 ℃, in addition, the particle size is smaller, the rate of gasification is faster. With the change of gas flow, the initial reaction temperature, evaporation rate and fixed carbon gasification respectively has reached a maximum and minimum values in 90 ml/min, it seems the“^”shaped change. Heating rate on gasification reactivity of two kinds has a great influence, the heating up speed is faster, gasification reaction temperature is higher, and reaction lag phenomenon occurs in the late gasification reaction, which leads to the double peak of phenomenon.The FWO method and the differentiation of equivalent conversion are used to get the gasification reaction activation energy of semi-coke, the results respectively are（145.91±32） kJ/mol and（149.21±7） kJ/mol, and the two obtained results is a more consistent; the activation energy of volatile obtained analysis is（5.5±1） kJ/mol. The Malek method is used to infer semi-coke gasification reaction mechanism function. When the volatile influence on gasification reaction process is ignored and the fixed carbon gasification process is considered, gasification reaction conforms to the J-M-A equation which is the mechanism of random nucleation and subsequent growth.