Experimental study on the production of H2 -CH4 from lignite jointly with acid-alkali pretreatment-microbial gasification

In order to investigate the characteristics of the production of biogenic gas from lignite with acid-alkali pre- treatment,the authors carried out the fermentation experiments of hydrogen and methane production by using cultured bacteria from coal seam water in Guhanshan coal mine,as well as acid and alkali pretreatment of lignite in Yining Mine,Xinjiang. The authors measured gas production,gas components,activity of hydrogenase,COD concentration,and tested XRD and FTIR for coals after gas production. The results show that:① The hydrogen production of coal with al- kali pretreatment is the highest with the total gas production by 20. 25 mL / g, the coal with acid pretreatment is 17． 05 mL / g,and the lowest hydrogen production of raw coal is 14. 4 mL / g;② The determination of HPE is basically corresponding to it, and the hydrogenase activity of hydrogen production from coal with alkali pretreatment is 4． 35 mL / (mg·min);③ Methane production of coal from acid pretreatment is the best,and the total gas production is 23. 35 mL / g,while the effect of raw coal and the coal with alkali pretreatment is similar;④ The concentration of COD in the combined production shows a decrease;⑤ The organic matter degradation rate of pretreated coal sample is higher,and the macromolecular structure is more easily degraded. The results show the fermentative biogas characteris- tics of pretreated coal,and it proves that the combined production of H2 -CH4 is beneficial to the utilization of coal, which obviously improves the energy conversion rate.