The Study On Pyrolysis Characteristics Of Xinjiang Coal

In our country, low rank coal reserves are abundant, which possesses excellent characteristics for chemical processing. The features of low gray, low sulfur, low nitrogen content and high volatile content determined that it is particularly suitable for pyrolysis in medium and low temperature. Low rank coal utilization technology primarily coal pyrolysis has the following advantages:low energy consumption, excellent economy, low pollution, high efficiency of resource utilization, considerable environmental benefits, meeting the needs of our energy strategy in present stage in China. In this paper, Xinjiang (XJ) coal has been selected as the research object, and a relatively comprehensive study of the basic properties and pyrolysis characteristics is discussed.TG-FTIR was used to analyze the XJ coal pyrolysis weightless process and gas product evolution rules, investigating the effects of particle sizes, the slow heating rates and relatively rapid heating rates on coal pyrolysis characteristics. The results obtained that TG and DTG curves are similar with the change in particle sizes and that the weight loss increases as the particle size increases. But contrasting the proximate analysis of coal in different sizes, it found that its organic matter content is improving as the particle size increases, which may be one of the reasons of different weight loss; With heating rate increasing, the temperature corresponding to the maximum weight loss rate lifted and the pyrolysis conversion rate enhanced, too. XJ coal pyrolysis data at different heating rates were fitted, and the kinetic parameters were calculated when n=1. It was found that the activation energy increases with the increase of heating rate.The powder-particle fluidized bed experimental device for pyrolysis was set up in our laboratory, and the effects of superficial gas velocity and pyrolysis temperature were researched with the use of powder-particle fluidized bed. The results show that:with the final pyrolysis temperature increases, char yield under different gas velocities exhibit similar decreasing gradually and eventually becoming stable, and the yield of char reduced as gas velocities increasing; The tar yield is influenced by the temperature and residence time. therefore, in this experimental conditions of the device, in order to get bigger tar yield, the temperature for pyrolysis should be in the range of 600? to 650?, gas flow rate should be controlled between 0.216 m/s to 0.276 m/s; The pyrolysis gas yield under various gas velocities shows a clear tendency to increase with the final pyrolysis temperature increases, so is the yield of BTX in tar, which comes to around 0.4%, when it is 750?. GC-MS analysis on tar showed that the content of phenol compounds are highest, the proportion of which is nearly 28.04% at 650? and the simple phenol accounted for about 60% of phenols.