Analysis Of Pyrolysis Characteristics And Pyrolysis Products Of Dongsheng And Wanli Long-Flame Coal And Their Vitrinites

As an important power coal and civil coal in China,long flame coal is not only an important primary energy,but also an ideal chemical and chemical production raw material,which plays an indispensable important position in China’s energy structure.However,since coal is an extremely complex mixture of different macerals,the chemical composition and structure of coal with the same or similar metamorphism are different.The vitrinite plays an important role in the coal pyrolysis process as an organic micro-component with strong hydrocarbon generation capacity and relatively high content in coal.For this reason,the two types of long-term in Inner Mongolia Dongsheng and Wanli coal fields Flame coal and its vitrinite coal are the research objects.The three methods of synchronous thermal analyzer,thermogravimetric-mass spectrometer and Gray-King dry distillation furnace are used to investigate the differences of pyrolysis characteristics and pyrolysis products,which could investigate the influence factors of coal pyrolysis process from a relatively microscopic perspective.The main contents and conclusions are as follows:（1）The macroscopic pyrolysis characteristics of the sample were investigated by a synchronous thermal analyzer.The chemical reactivity of the whole pyrolysis process of the coal sample was quantitatively analyzed by the pyrolysis characteristic index P.The change rule was found as follows:P_WLV>P_DSV>P_DS>P_WL;By solving the pyrolysis activation energy at the main pyrolysis temperature（400⁶00^oC）with Coats-Redfern equation,it can be seen that the pyrolysis activation energies of DS and WL coal and their vitrinites coal are 43.66,50.42,33.32,38.24KJ/mol,respectively.The above results show that vitrinite coal has higher thermal reactivity than raw coal,and raw coal has higher thermal stability than vitrinite coal.（2）The composition of pyrolysis volatiles and the yield distribution under the main pyrolysis temperature were investigated by TG-GC/MS.The results showed that the main components of pyrolysis volatiles were aromatic monocyclic and aliphatic hydrocarbon compounds,and their content reaches a maximum at 450^oC.In pyrolysis volatiles,the substituent groups of monocyclic aromatic compounds are mainly 1 and2,the carbon chain length of monocyclic aromatic compound substituents is mainly C₁,and the carbon chain length of aliphatic hydrocarbon compounds is mainly C_6--10.At the same pyrolysis temperature,the relative content change law is:DSV>WLV>DS>WL,that is,the volatile matter content of the vitrinite coal is greater than the volatile content of the corresponding raw coal,and the pyrolysis volatile content of DSV coal is greater than that of WLV coal.（3）The solid,liquid and gas products of the pyrolysis process were obtained by the Gray-King pyrolysis device,and the yield distribution of the products,the evolution of the main pyrolysis volatiles and the adsorption characteristics of the solid products were investigated.The experimental results show that at the same final pyrolysis temperature,the percentage of CO₂ in the pyrolysis gas of raw coal is greater than that of the corresponding vitreous coal,while the percentage of CO,CH₄ and C_mH_n in the pyrolysis gas of raw coal shows the opposite results.The pyrolysis coal tar was dominated by aliphatic substances and phenolic substances,and the content of each component reached the maximum value at 500^oC.The aromatic monocyclic substances in low-temperature pyrolysis coal tar are mainly substituted by 2 and 3,the carbon chain length of monocyclic aromatic hydrocarbon substituents is mainly C₁,and the long-chain substances in aliphatic hydrocarbon compounds(C_>20)are mainly.The pyrolysis tar component of vitrinite coal is greater than that of raw coal,and the pyrolysis tar component of DSV coal is greater than that of WL coal;The pyrolysis semi-coke was applied to the adsorption experiment of simulated azo dye（Congo red dye）in printing and dyeing wastewater.The results show that the removal rate and adsorption rate of dye in the pyrolysis semi-coke of raw coal is much higher than that of vitrinite coal pyrolysis semi-coke.The removal rate and adsorption capacity,and the removal rate and adsorption capacity of dyes of WL coal pyrolysis semi-coke are higher than that of other coal pyrolysis semi-coke.