半焦制铸造型焦热解动力学分析

以半焦、烟煤、气煤、沥青为原料,消除内、外扩散影响的基础上利用热重分析仪获得失重曲线,并通过3种动力学方法计算出活化能,分析了动力学特征.Friedman分析法和Ozawa-Fly-nn-Wall(OFW)法得到了活化能的变化趋势,前者更为可靠,DAEM模型得到了和Friedman分析法相近的结果.结果表明:整个炭化过程中升温速率越快,失重越快,但终温时,型焦残余量与升温速率无关.对半焦制铸造型焦的热解动力学分析结果表明:混合料的热解不是简单的一级反应,在转化率0.1～0.6范围内(204～481℃),反应的活化能在116.27～363.22 kJ/mol之间;转化率大于0.6后,反应的活化能降低到100 kJ/mol左右,活化能的变化可为型焦生产中焖炉工艺和升温制度提供依据.

Pyrolysis Kinetic Analysis of Foundry Formed Coke Prepared by Semi-Coke

The semi-coke, gas coal, soft coal and pitch were used as raw materials, the thermo-analysis curves were obtained by a thermogravimetric apparatus with free of both internal and external diffusion. Kinetic parameters including activation energy were evaluated by three dif-ferent methods. The relationship between activation energy and conversion ratio can be deter-mined by a Friedman method and Ozawa-Flynn-Wall(OFW) method, and the result by the for-mer are more credible. The activation energy obtained by DAEM method approximated to that by Friedman method. The results show that the faster the heating rate is in the carbonization process, the faster the weightlessness is. At the final temperature, the residual volume of mix-ture is indpendent of heating rate. The pyrolysis of the mixture is not a simple first order reac-tion. The activation energy is 116.27-363.22 kJ/mol when conversion ratio is 0.1～0.6 at 204-481 ℃, while the activation energy is about 100 kJ/mol when conversion ratios is more than 0.6. This variation of activation energy can provide basis for the braise furnace technology and heating program in the process of preparing foundry formed coke.