Production of syngas for the reduction of sulfur dioxide by methane via a direct RF plasmalysis process

The traditional process for the reduction of SO 2 by CH 4 usually leads to enrichment of the effluents with H 2 S and CO 2 . In this study, a radio‐frequency (RF) plasma system was applied to generate useful byproduct: syngas (H 2 and CO) at room temperature. Experimental results indicate that the H 2 /CO ratio increased with the elevation of inlet [CH 4 ]/[SO 2 ] ratio ( R ), or the decrease of applied power ( E ) or operational pressure ( P ). H 2 /CO values ranged from 1.34 to 4.28 and reached 2.09 and 1.95 for E = 90 W and 120 W, respectively, at R = 1 and P = 4000 N m −2 . At first the selectivity to CO increased with the elevation of R or E , while the selectivity to H 2 was only decreased at R > 2 whatever the power that was supplied. However, at R = 2, optimum selectivities of H 2 and CO, and decomposition efficiencies of CH 4 and SO 2 , were achieved. The decomposition efficiencies and product components strongly depend on E or R . CH 4 is more easily decomposed than SO 2 and yields mainly syngas, with traces of CO 2 , C 2 H 2 , and C 2 H 4 . In addition, sulfur‐containing compounds including major amounts of CS 2 , elemental sulfur and minor amounts of COS, but no toxic H 2 S, were observed. The formation pathways of syngas are also proposed to provide useful information to gain insight into the CH 4 conversion in the RF plasma. Copyright © 2003 Society of Chemical Industry