Poster (EARTH)

[PE1-057] Plasma desulfurization of an underground coal gasification gas

○Kazuhiro Takahashi¹, Kohki Satoh¹, Ken-ichi Itakura¹ (1. Muroran Institute of Technology)

Keywords:Underground coal gasification, Hydrogen sulfide, Desulfurization, Discharge plasma

An artificial underground coal gasification (UCG) gas, the mixture ratio of which is (N₂+CH₄)/CO₂/H₂/H₂S = 64.7/20.0/15.0/0.3-0.35%, is decomposed using a packed-bed dielectric barrier discharge (PB-DBD), the by-products of the UCG gas are measured by infrared absorption spectroscopy (IRAS), gas chromatography (GC) and gas chromatography mass spectrometry (GCMS), and then the desulfurization characteristics of the UCG gas are investigated. A PB-DBD reactor consists of a glass tube filled with dielectric fillings, an inner rod and an outer mesh electrodes. Soda-lime glass balls and activated alumina (Al₂O₃) balls are used as the dielectric fillings. The artificial UCG gas is fed into the reactors at a constant flow rate of 0.5 L/min, and a high-voltage generated by a neon transformer is applied to the electrodes, generating a PB-DBD. It is found that H₂S in the UCG gas is selectively decomposed by the PB-DBD without H₂ decomposition. The decomposition rate of H₂S in the UCG gas without CH₄ using the PB-DBD reactor filled with Al₂O₃ balls is approximately 1.9 times higher than that using one filled with glass balls, however, the decomposition rates of H₂S decrease with the increase of CH₄ content, and these become almost the same at the CH₄ content of more than 30%. It is also found that CO, COS, and CS₂ are produced as by-products during the plasma desulfurization, and that CH₃SH, C₂H₅SH, (CH₃)S, CH₃SC₂H₅, and (CH₃S)₂ are produced only when CH₄ is contained in the UCG gas. Furthermore, SO₂ is detected in the PB-DBD reactor filled with glass balls by IRAS and GCMS, while not detected in one filled with Al₂O₃ balls due to the adsorption of SO₂ on the surface of Al₂O₃.