Evolution Kinetics And Mechanisms Of Volatile From Dongwuqi Lignite And Different Chemical Compoments

The majority of scholars has paid more attention to lignite, beacause of the reserves and widely use of it. Based on analysis of FTIR and TG-MS, the kinetics of pyrolysis and the emission of pyrolysis gases were studied on Wunite lignite, the humic acid, the residuals after humic acid was removed, the asphalt and the residuals extracted by pyridine. Main conclusions are drawn as follows:1.The structure characteristic:the fa is reduced with the increase of H/C and increase with the increase of O/C; there are environment of polarity exist in coal and five replace modes of benzene; at the influence of the acid and alkali, the aromatic vibretion peak and aliphatic stretching vibration become weaker; after the extracted by pyridine, the peak attributable to the aromatic structure become weaker.2. The characteristics of coal during pyrolysis:as lignite is a low rank coal, the temperatures of coal during the initial pyrolysis is low; because of the impact of the pyridine, the asphalt and asphalt residues are more prone to thermal decomposition, loss bigger weight and response quickily; as the glial body is not generated during coal pyrolysis, the higher reactivity of char, the activation energy of the most violent phase of pyrolysis is higher than the final stage.3. The interaction between the pyrolysis gases:lignite contains more water than other coal; the aliphatic chain of the oxygen-containing functional group generate methane, water and carbon dioxide during pyrolysis; As the environmental impact of acid-base, the type of the keys which generate methane reduce, the number of keys increase; because of pyridine, the type and number of the keys which generate hydrogen and methane increase.4. The characteristics of the gas escape from pyrolysis:the water during pyrolysis mainly from the dehydration of carboxyl and phenolic hydroxyl dehydration, phenolic hydroxyl and hydrogen radicals; carbon dioxide from the decomposition of coal in the carboxyl, hydroxyl with decarboxylation of aromatic carboxyl, carboxyl and oxygen groups in the fat side of the combined effect of strand breaks, and decarboxylation of aromatic carboxylic ester structure and the structure of the decarboxylation of anhydride; propane from the cleavage of the aliphatic chain of the oxygen-containing functional group, from the decompose of the side chain in the oxygen funcyional groups, fat free phase hydrocarbon is formed by cracking mechanism of free radical generation by free radical reaction between coal macromolecular structure and aromatization polycondensation; benzene come from pyrolysis methoxy on the benzene ring, benzene and ether oxygen bond occurs cracking, the long-chain hydrocarbons secondaryily generated by pyrolysis cyclization.