| Semi-coke is a kind of material with wide sources,low cost and high combustion heat,which can be widely used as a clean fuel in the field of metallurgy and chemical industry.The structure of ultra-fine coke also has certain adsorption performance,but because its particle size is too small,direct application will cause air pollution.In this project,the raw materials are semi-coke and ultrafine coke.Under the four heating rates of 2.5K/min,5K/min,10K/min and 20K/min,the combustion characteristics of semi-coke,ultra-fine coke and their mixtures were studied by thermogravimetry,and the ignition temperature,burnout temperature and corresponding temperature of the maximum combustion rate of semi-coke,ultra-fine coke and their mixtures were analyzed.The experimental results show that the mass fraction of the volatile matter in semi-coke is much higher than that in ultra-fine coke,which is equivalent to anthracite coal.However,the volatile content of ultra-fine coke is very low,and the ash,fixed carbon and sulfur content are all better than that of ordinary power coal.With the addition of ultra-fine coke,the ignition temperature and burnout temperature of the mixture decrease,which shows that ultra-fine coke can improve the combustion characteristics of semi-coke.In this paper,three kinds of reaction gas-solid models,volume model（VM）,random pore model（RPM）and unreacted core model（URCM）,and are selected to study the combustion kinetics of semi-coke,ultra-fine coke and their mixtures.Comparing the simulation results of these three models,it is found that RPM model can better describe the combustion process of the mixture of semi-coke and ultra-fine coke,and it is the most suitable model to simulate the mixture of semi-coke and ultra-fine coke.Finally,in order to improve the utilization efficiency of coal combustion in power plant,obtain a new type of high-efficiency and practical combustion supporting,and sulfur fixing agent,an experimental study on combustion supporting and sulfur fixing was carried out by using thermogravimetry.The influence of different sulfur fixing agents,additives and combustion supporting agents on the combustion rate and sulfur fixation rate of the mixture of ultra-fine coke and semi-coke（mass ratio of 8:2）was analyzed.The result of the experiment was analyzed and the final result was the best The optimum composition and technology of combustion supporting and sulfur fixing agent are as follows:Na OH as sulfur fixing agent,0.3%Mn O2 as additive,Na/S molar ratio of 2.5,test temperature of 1173K,pretreatment time of 30min,adding 2.0%Cu Cl2·H2O as combustion supporting component,the maximum sulfur fixing rate and combustion rate are 60.53%and 74.20%,respectively. |
