Preliminary Study On Methane Production Method Of Anaerobic Fermentationof Coal

Coalbed methane production enhancement technology is a method to convert coal into biomethane by improving the anaerobic fermentation process of coal,which is a promising and efficient clean coal utilization technology.Although coal has certain potential in methane production,the mechanism and process conditions of biocoalbed methane generation are not clear,and the effects of coal type,particle size and digestion temperature,inoculation amount,and addition of magnet powder on coal fermentation are studied to determine the coal samples with the most potential for gas production,exogenous conditions and optimal fermentation conditions.The observed indicators were gas production,peak gas production time,p H,ORP,maximum gas production rate,cumulative gas production,etc.,and oneway ANOVA was performed to determine the easy factors that had a significant impact on the fermentation process.The main results are as follows:(1)Lignite is the coal with the best gas production potential.There was a significant negative correlation between the peak daily gas output and the total gas production and the maturity of coal.Anthracite coal is the first to reach the peak gas production.(2)75μm is the optimal coal particle size for anaerobic fermentation of coal.There is a significant relationship between coal particle size and fermentation gas production.According to the particle size,the cumulative gas yield increase decreases when the particle size decreases,and its influence on the fermentation gas yield gradually decreases when the particle size < 150μm.(3): 40°C is the optimal temperature for coal fermentation under the same experimental conditions.The gas production peak of the 40°C group was two days earlier than that of other experimental groups,and the peak gas production had different degrees of lag when the temperature was higher or lower than 40°C.The cumulative gas yield and maximum gas production rate of the 40°C group were better than those of other experimental groups.When the fermentation temperature is less than 40 °C,the temperature is positively correlated with the gas production,and the gas production is inhibited when it is higher than 40 °C.(4)When 40 g of pulverized coal is used as the fermentation substrate,the amount of activated sludge is 200 ml,which is the optimal ratio of inoculation amount.The total gas production of this group was higher than that of other groups;However,the other groups lagged behind the peak gas production due to improper ratio of activated sludge inoculation amount.(5)When the magnet powder is added to 5% of the substrate,biogas can be assisted to the greatest extent.The maximum gas production rate has been greatly improved;After adding an appropriate amount of magnet powder,the p H decline trend of the liquid in the first half of fermentation slowed down.By observing the number of methanogens,it can be seen that the addition of 5% magnet powder can rapidly increase the density of methanogins in the first half of fermentation.In summary,after the gradual optimization of the methane production process of anaerobic fermentation of coal,the maximum daily gas production rate increased significantly,the gas production peak appeared earlier,the total gas production was significantly improved,the fermentation cycle was shortened,and the gas production efficiency was greatly improved.