Research On Microbial Desulfurization Of Organic Sulfur In Coal Of Yunnan

High-sulfur coal must be desulfurization before being used, because they would generate a lot of SO2 gas in combustion and lead to serious air pollution. Although physical and chemical methods can remove inorganic and organic sulfur simultaneously, they are not the best choice for desulfurization of coal in consideration of the cost and environmental friendly. Microbial desulfurization of coal is an ideal technique to complete the desulfurization due to its low cost、mild reaction condition and environmental friendly. Yunnan is one of the famous coal-producing provinces with high organic sulfur in coal, it is urgent to develop microbial desulfurization of coal in Yunnan.Coal samples were collected from Guishan, Xiaolongtan and Yiliang Bridge ditch coal mines of Yunnan province, respectively, activated sludge from sewage treatment plant was used as resource of bacteria. All coal samples were treated with bacteria from activated sludge to determine if their content of organic sulfur can be reduced after processing. No significant reduction of organic sulfur in coal can be observed, although the content of medium, cultivation temperature and pH was modified during processing. Eight bacterial strains were isolated from samples by using series dilution method with Dibenzothiophene (DBT) as carbon and sulfur resource. These isolates were identified as Rhizobium sp., Xanthobacter sp., Rhodococcus erythropolis sp., Rhodococcus sp., Pseudomonas sp., Arthrobacter sp. and Moraxella sp., respectively. The capacities of desulfurization of organic sulfure in all isolates were determined by HPLC with DBT as substrate. Among 8 isolates, only 6 isolates showed desulfurization capacity. Strain HWBHT2 could degrade DBT with degration rate of 45.8% after sample was processed by 3 d, and strain XFJ2 had degration rate of 76.2% when sample was processed by 7 d. HWBHT2 and XFJ2 were used to treat the Yunnan smoke coal and the desulfurization was determined by Yunnan Province Coal product Quality Supervision and Inspection Station. Two strains did not show any desulfurization capacity, although some medium and physical conditions were modified. The main reasons are considered, the first reason is that the organic sulfur in Yunnan smoke coal may not be DBT, the second reason is that some contents in coal inhibited the growth of bacteria.Six bacterial strains were isolated with the capacity of degrading DBT. This study provides a theoretical and practical basis for further developing practical application techniques for removing organic sulfur in coal.