Basic Research On Microbial Gasification And Desulfurization Of Coal

China is a country rich in coal,poor in oil and little in gas.Coal resources are the lifeblood of China's national economy.However,the pollution generated by its combustion is against the concept of green,scientific and sustainable development advocated by today's society.The desulfurization and transformation of coal have opened up a new road for the sustainable development of the coal industry,which is in line with China's strategic needs and has a broad prospect for development.In this paper,the microorganism gas production experiment of low-rank coal was studied,and the desulfurization effect of microwave irradiation on high-sulfur coal was studied.Taking low-rank coal as the research object,the anaerobic fermentation flora in biogas slurry was collected as the foreign bacteria source,and the anaerobic fermentation methane production experiment was carried out on coal after the enrichment and culture of the flora.Through single factor experiment and studying the coal sample temperature,pH,coal particle size and the ratio of the microbial amount on the biological effects of methane,the analysis of test results to determine the optimal conditions of single factor,the temperature of 35?,pH=7,coal sample size from 0.075 mm to 0.15 mm,coal and the ratio of the bacteria liquid dosage is 1:5,biogas slurry under the condition of anaerobic bacteria group of gas production peak.Three factors,temperature,pH,ratio of coal(g)to liquid bacteria(mL),were selected.Three levels of each factor were selected for the orthogonal test.The experimental results show that temperature and pH have significant influence on coal microbial gasification,while the effect of the ratio of coal and bacteria liquid is not obvious.The optimal conditions of orthogonal test are consistent with the results of single factor test.Methanogens,which make use of peat and coal molecular after the single molecule and oligomer,methanogens in hydrogen and acidifying bacteria output under the joint action of hydrogen,carbon dioxide and acetic acid,and then produce hydrogen is to generate methane carbon dioxide reduction and acetic acid decomposition,temperature,pH,mainly through microbial metabolism to change from domestic production.The high-sulfur coking coals in shandong and shanxi were selected for the microwave irradiation desulfurization test,and the desulfurization rate was calculated.The changes of functional group absorption peak and relative content of morphological sulfur in the coals before and after irradiation were analyzed,providing a theoretical basis for the subsequent microbial gas production test of high-sulfur coals after microwave irradiation.The desulfurization experiments were conducted under microwave equipment with frequency of 915MHz,power of 2000W,frequency of 2450MHz and power of 700W,respectively.At the same time,infrared spectrum and XPS data fitting analysis were performed on the coal samples before and after irradiation.As can be seen from the results of the changes in the relative content of functional groups and morphological sulfur of coal under microwave irradiation,the response rules of coal to microwave are also different.The desulfurization of coal is affected by the microwave frequency and irradiation time,and the relative content of morphological sulfur in coal will also change obviously even if the desulfurization rate is not high.The results show that microwave irradiation can affect the si-o-bond and organic sulfur(aromatic disulfide-s-s-or-sh)in coal,and may produce new sulfur-containing substances,such as sulfates.In shanxi and shandong high-sulfur coking coal,organic sulfur mainly occurs in the form of thiol(ether),thiophene and(sulfone),while inorganic sulfur content is relatively small.The relative contents of thioether(alcohol)and thiophene in organic sulfur were significantly affected by the microwave frequency,and the microwave frequency had little effect on(sulfoxide).However,with the increase of irradiation time,the relative contents of(sulfoxide)decreased significantly.The relative content of organic sulfur in shanxi and shandong coals was transformed by microwave irradiation,the overall content of organic sulfur was reduced,and the relative content of inorganic sulfur was increased,indicating that microwave irradiation completed the transformation from organic sulfur to inorganic sulfur in coal and achieved coal desulfurization.