Application of acoustic emission monitoring during underground coal gasification

A. Hamanaka, K. Itakura, F. Q. Su, G. Deguchi, J. Kodama

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Underground coal gasification (UCG) is a process of producing combustible gases by the in-situ conversion of coal into gaseous products. Coal resources abandoned under the ground for either technical or economic reasons can be recovered with economically and less environmental impacts by UCG; therefore, this technology is regarded as a clean coal technology. UCG has several advantages of low investments, high efficiency, and high benefits compared to conventional coal gasification. However, some environmental risks such as gas leakage, surface subsidence, and underground water pollution are difficult to control because the process is invisible. The reactor in UCG is unstable and expands continuously due to fracturing activity caused by coal combustion. It is, therefore, considered that acoustic emission (AE) is an effective tool to monitor the fracturing activities and visualize the inner part of coal. For this study, UCG model experiments were conducted using coal blocks of 0.55 × 0.60 × 2.74 m to discuss the applicability of AE monitoring for the estimation of the crack generations during UCG process and the extent of the gasification area. Temperatures were also monitored to understand the inner part of coal blocks because the crack generations were strongly related to thermal stress occurred by coal combustion and heat transfer. The monitoring results of AE agree with the measured data of temperatures; the source location of AE was detected around the region temperature increased. AE monitoring are expected to provide a useful data to visualize the gasifier in the underground.

Original languageEnglish
Title of host publication4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017
PublisherInternational Society for Rock Mechanics
Number of pages4
ISBN (Electronic)9791156103158
Publication statusPublished - 2017
Event4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017 - Jeju, Korea, Republic of
Duration: May 10 2017May 13 2017

Publication series

Name4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017


Other4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017
Country/TerritoryKorea, Republic of

All Science Journal Classification (ASJC) codes

  • Geotechnical Engineering and Engineering Geology
  • Geophysics


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