Experimental Study on the Mechanism of Radial Change of Simulated Enrichment Nutrient Solution Injection into Coal...

This paper deals with enhanced coal bed methane recovery and geological CO₂ storage, combined with the dual effect of increasing coal-bed methane and achieving carbon emission reduction. Coal of different particle sizes were loaded into acrylic tanks of a certain height, and peristaltic pumps were used to enrich nutrient solution and CO₂ into different layers of coal seams, to monitor the liquid phase pH, COD, OD₆₀₀, aromatic structure, HCO₃^-, three-dimensional fluorescence data of the upper, middle, and lower layers, and the specific surface area of coal Poreginseng. The following conclusions were drawn: (1) the reaction with CO₂ resulted in a lower pH than that without CO₂, with weak acidity and higher concentration of HCO₃^- ions. The OD₆₀₀ concentration and activity of the bacterial solution were stronger. Most of the solution was dominated by Clostridium acidophilum, and the three-dimensional fluorescence results are also shown. (2) Coal samples with small particle sizes had a larger surface area, more contact area with bacterial liquid, and a more complete reaction, so the physical property transformation of coal reservoirs with small particle sizes was more obvious, and the COD change was the largest. (3) The upper and middle layers were exposed to more bacterial fluid and CO₂, resulting in a more complete degradation reaction.