| Underground coal fire(UCF)is a phenomenon of coal combustion around the world,which mainly caused by mining activities.In China,the coal fire is serious in north part of this country,especially in Xinjiang region.UCF not only burns up the coal resource,but also causes serious impact on local eco-environment.How to quantify the UCF’s impact on environment,especially the producing of typical pollutants from UCF,is the core of research in this field.This paper focuses on the burning coal seam of coal fires in Eastern Junngar coal field to study the producing characteristics of typical pollutants from coal fire with respect to different aspects,such as the reactants and products,the kinetic parameters,the particle sizes,etc.Methods,such as the Thermogravitic analysis of coal samples,the programmed temperature-rising experiments,and the chemical simulation with FACTSage,were involved in this research.From the TGA data of coal samples,the characteristic temperature,reaction activation energy,and the reaction velocity constant,were obtained.Some factors,such as the particle size and the coal proximate,also were analyzed.Results show that the reaction characteristic temperature and the reaction activation energy fluctuate with the decrease of coal sample particle sizes.The reaction activation energy increases with the increase of the content of fixed carbon for coal samples.And with the increase of ash content and total sulfur content,the reaction activation energy decreases.From the programmed temperature-rising experiments,gaseous products from coal samples oxidation experiments were analyzed through different aspects,such as the particle size,coal proximate,reaction temperature,etc.Result show that the CO2 and the CO are the main gaseous products.Some trace gaseous CnHm products also were detected in smoke.With the decrease of particle size,the amount of CO2,the CO,the CH4,the C2H2,the C2H4,the C2H6 and the C3H8 show irregular fluctuation.The amount of products from coal oxidation increases with the increase of reaction temperature.Result also show that the change of typical gases producing rate coincides with the oxygen consumption rate and the reaction velocity constants.From FACTSage simulation of different coal and oxygen reactants system,the kinds of products and their distribution at different temperature(100℃,200℃,300℃,500℃,700℃,900℃,1100℃)were analyzed.Result also show that the main products are the CO2 and CO associated with trace Hg and As compound.From research of this paper,the kinetic parameters of coal oxidation for burning coal seams in Eastern Junggar coal field were firstly analyzed.The kinds of product from the oxidation of these coal seams also were studied firstly by programmed temperature-rising experiments and FACTSage tools. |
