Integrated Process Of Coal Pyrolysis With Oxidative Coupling Of Methane

The composition of coal pyrolysis products can be regulated by hydrogen-rich atmosphere.Understanding regulatory mechanism of products can promote process optimization and industrialization.In this paper,aiming at the improvement of tar yield in coal pyrolysis process,a research on the role of CH₄ and CH₄-O₂ atmospheres in the low-temperature pyrolysis of coal was undertaken,and the coupling process of coal pyrolysis and methane oxidation coupling reaction was studied.The main conclusions are as follows:?1?Compared with the tar yield under N₂ atmosphere,the CH₄ atmosphere can increase the tar yield at temperatures above 650?;the tar yield was significantly improved under CH₄atmosphere at 650?,but lower than the tar yield under H₂ atmosphere.Adding O₂ into the methane atmosphere as the pyrolysis atmosphere,the tar yield was higher than that in the CH₄atmosphere when the temperatures was 650?.In the process of coal pyrolysis and methane oxidation coupling reaction?OCMP?,the tar yield is higher than that of pyrolysis tar in N₂,CH₄,CH₄-O₂ atmosphere.The yield of Naomaohu coal during the OCMP process was 1.9times that of N₂ atmosphere and 1.4 times that of CH₄ atmosphere.It shows that OCMP process has a significant improvement effect on tar yield.?2?CH₄ was conducive to the formation of anthracene oil and wash oil at 600?.CH₄was favorable to the generation of all fractions in tar,and especially the content of light oil was higher than that in H₂ atmosphere at 650?.Compared with N₂ and CH₄ atmospheres,the content of naphthalene oil,wash oil and anthracene oil in CH₄-O₂ were increased above 650?.Under different temperature conditions,the content of asphalt in CH₄-O₂ was obviously higher than that in CH₄ and N₂ atmosphere,but the content of light oil and phenol oil was lower.It showed that adding O₂ into the methane atmosphere was not conducive to further improve the quality of pyrolysis tar.The OCMP process is also conducive to improving the quality of coal tar,and the bitumen content in tar is also high,which is not conducive to the deep utilization of tar.?3?Compared with the N₂ atmosphere,CH₄ was favorable to the generation of phenols and alcohols at 600?.CH₄ was beneficial to the formation of aliphatic hydrocarbons,aromatics,olefins,phenols,esters and alcohols when the temperature was 650?.Compared with the CH₄ atmosphere,the addition of O₂ in the methane atmosphere was conducive to the formation of aliphatic hydrocarbons,aromatic hydrocarbons,olefins and alcohol compounds.The content of phenolic compounds was lower at a temperature within the range of 600?to650?,and it was not conducive to the formation of ester compounds at all temperatures.Compared with the CH₄ and N₂ atmospheres,the content of aliphatic hydrocarbons,phenols and alcohols increased significantly during the OCMP process.?4?Compared with N₂ atmosphere,the content of aliphatic hydrogen and aliphatic carbon in pyrolysis tar was lower under H₂ atmosphere,and the content of aliphatic hydrogen and aliphatic carbon in pyrolysis tar was higher in CH₄ atmosphere.The results showed that methane took part in the reaction of coal tar formation and increased the length and number of aromatic side chains.Compared with CH₄ atmosphere,under CH₄-O₂ atmosphere,the content of condensed ring aromatic hydrogen in tar increased,while the content of monocyclic aromatic hydrogen decreased.The content of aromatic quaternary carbon in tar increased significantly.It showed that adding some O₂ into the methane atmosphere was not conducive to further improve the degree of lightening of pyrolysis tar.