328 Field-Scale Demonstration on Underground Coal Gasification to Utilize Untapped Resources: A Field Trial on Remained Coal Seam in Surface Mine * R. Iriguchi1, A. Hamanaka1, K. Itakura2, G. Deguchi3, K. Takahashi2, J. Kodama4, T. Sasaoka1, H. Shimada1 1Department of Earth Resources Engineering, Kyushu University, Japan, (*Presenting author: iriguchi.rika.842@s.kyushu-u.ac.jp) 2Muroran Institute of Technology, Hokkaido 050-8585, Japan 3Underground Resources Innovation Networks, NPO, Hokkaido 007-0847, Japan 4Hokkaido University, Hokkaido 060-0808, Japan ABSTRACT Coal, one of the world’s major energy resources, still has more than 50% of its reserves unrecovered due to economic and technical limitations. In addition, coal is often regarded as a resource with high environmental impact due to its significant CO2 emissions during combustion. In this context, Underground Coal Gasification (UCG), which converts coal underground into combustible gases such as hydrogen and methane, offers the potential both to recover otherwise unrecoverable resources and to utilize coal as a cleaner energy source. Figure 1 shows a conceptual diagram of Underground Coal Gasification (UCG), in which the composition of gases recovered from coal can be controlled by adjusting the injected oxidants and the coal seam temperature. Furthermore, voids generated after UCG and fractures in abandoned mine workings can serve as CO2 storage sites, thereby contributing to greenhouse gas reduction and the production of CO2-free (blue) hydrogen. This paper reports the results of a UCG field test conducted on the coal seam at an open-cut mine. The test aimed to evaluate the field applicability of the combined co-axial method, which employs a co-axial well together with an auxiliary production well. This method had previously been shown to effectively enlarge the gasification zone in artificial coal seam experiments. In the test, one co-axial well, one auxiliary production well, and one monitoring well were drilled. An oxidant injection pipe, also serving as an ignition device, was installed in the co-axial well, and ignition was initiated at the wellbore bottom within the coal seam. Following ignition, coal around the co-axial and auxiliary wells was gasified to produce UCG syngas. The recovered syngas was analyzed to evaluate the gasified coal volume, gas production rate, gas composition, and gasification efficiency. The gasification efficiency reached approximately 70%, with syngas containing up to 30% of H2, indicating high-efficiency gasification with low thermal losses. KEYWORDS UCG, Gas Chromatograph, Hydrogen production, Blue hydrogen, Field test
RkJQdWJsaXNoZXIy MTM0Mzk2