| Though the rapid development of coal liquefaction technology. A large amount of coal liquefaction residue was produced, even reached to30%. The effective and reasonable appli-cation of coal liquefaction residue appears particularly important and urgent either for the energy efficient or economic benefits. Coal liquefaction residue was composed of unliquefied coal, mineral matters, liquefaction products and catalyzer added before reaction. It possesses the features of low-moisture, high-carbon, high-ash, rich-hydrogen and high-sulphur. Due to the high content of sulphur, it brings many difficulties for the application of coal liquefaction residue. In the paper, the changing and transferring regularity of sulfide was studied with different atmospheres by thermogravimetry and fixed-bed using Shenhua coal residue as raw material. And adopting activated coke made by coal loaded different kinds of sulfur-containing model compound structures to simulate the reaction environments, explores the formation of sulfide and provide the theory basis for application of liquefaction residue.According to the analysis of TG about coal liquefaction residue and pre-treat samples at N2、CO2and Air atmospheres, the research found that the liquefaction residue has two weight loss steps, low-temperature organic matter pyrolysis and high-temperature mineral decompo-sition in N2. The low-temperature loss step in CO2was same in N2. In high-temperature period, gasification reaction caused the weight loss. It has one weight loss step in air, because combustion reaction happened in the temperature near580℃. The TG curves of sample treated by nitric acid were similar to the untreated residue in any kinds of atmospheres. The THF-insoluble residue has no weight loss in low temperature with N2or CO2for most of organic matter was removed. Decomposition and gasification separately caused the loss in high temperature period. The peak height receded sharply and the corresponding temperature was lowered considerably in air. The THF-soluble residue only has no weight loss in high temperature, except for it in low temperature at N2and CO2atmospheres. Before the agravic peaks caused by combustion there was one due to pyrolysis in air. The weight loss peak height by combustion receded and the corresponding temperature elevated considerably.The research of BET showed that treatment by nitric acid completely destroyed the pore structure of residue. The surface area and the pore volume of particle increased compared with original residue. Treatment by THF made the original hole bigger and opened up some pore closed before. Analysis of SEM-EDX could verify the changes of surface appearance and channel. Compared the elements in surface of all the samples, treatment by nitric acid could reduce the content of S on the surface. The content of S on surface of THF-insoluble residue increased. There was no metallic element on surface of THF-soluble residue.The study of fixed bed with temperature-programmed by mass spectrometric detector showed that the expulsion temperature range of sulfide was large in N2and CO2. The sulfur easily decomposed first escaped and translated, such as aliphatic sulfur and unstable structure of thioether sulfur. After that the simple substance of S decomposed by pyrite transformed into various kinds of sulfide. In high temperature the large molecule of stable organic sulfur decomposed. The substance of C4H4S generated and escaped to gaseous phase. Atmosphere CO2could promote the content of COS accompanying the evolution of H2S、CH3SH、SO2and C4H4S gas. The expulsion temperature range of sulfide was concentrated on the process of combustion reaction in air. Most of sulfur gases emission was SO2while simultaneously generating other forms of sulfur gases.Combined with study of fixed bed by MS, the research of thermogravimetry showed that pyrite has one weight loss step for the decomposition to generate S simple substance. Then S reacted with free radicals from active coke translating into sulfur gases. In N2and CO2, the kinds of sulfides were same, but CO2would promote the content of COS. All S elements translated into SO2gas. Ferrous sulfate only decomposed out SO2gases in any kind of atmosphere. However the atmosphere could affect the decomposition temperature of ferrous sulfate. Except S2(Dibenzothiophene), the other four kinds of organic sulfur-containing model compounds all had weight loss in low temperature period to generate the S and large molecules free radicals in N2and CO2. With increasing of temperature, combination between S free radicals and active coke would fracture and the S free radicals released again. Then these S reacted with free radicals from active coke translating into SO2、COS and H2S. But the CO2atmosphere made most of S free radicals translate into COS. The S elements in all five kinds of organic sulfur-containing model compounds would be oxidized to SO2gas.The model of CF differentials means was used to analyze the dynamics of coal residue and pre-treatment samples. Respectively using Doyle and Coats-Redfern integral solution simplified dynamic equation to calculate kinetic parameters. The results showed that reaction of coal liquefaction residue and pre-treatment samples were accorded with one order reaction kinetics equation and both of convergence effects two integral solutions achieved ideal effect. All the correlation coefficient of R2was larger than0.98. The computational results of Doyle integral solution were larger than Coats-Redfern. However, they had the same change trend. Both of them could verify the law of thermal reaction. |
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