Evaluation of Methane Production and Mass Loss of Lignite During Promoting Organic Matter Decomposition with Hydrogen Peroxide

Abstract

We proposed a new gasification method that converts unused organic matter in sedimentary rocks to bio methane gas through the use of microorganisms, known as Subsurface Cultivation and Gasification (SCG). Our approach uses hydrogen peroxide (H₂O₂) to decompose organic matter rapidly into usable substrates for methanogens. We previously reported that H₂O₂ would be useful for effective SCG at lignite, and conversion of organic matter from lignite into biogenic methane with the help of microorganisms is expected to be highly profitable. However, changes of physical properties of the sedimentary rock seem to occur due to decomposition of sedimentary rock in the biogenic methane conversion with the SCG method. In this study, immersion tests using a H₂O₂ solution were performed on two types of lignite to estimate the quantity of low-molecular-weight organic acids and the producing potential for biogenic methane gas. In addition, mass loss rate of lignite with oxidative decomposition of lignite was examined. The mass loss of lignite with the oxidative decomposition increased with increasing the amount of substance in H₂O₂. Furthermore, it was confirmed that the loss rate depends on the lignite. The biomethane deposits might become mechanically unstable during promoting decomposition of organic matter of lignite seams, if lignite has the greater resource potential for biomethane.