Role of Benzene on Thermal Stage Performance in a Claus Process

Abstract

Experimental results are presented on the role of benzene addition to H2S combustion at an equivalence ratio of three with respect to H2S and complete combustion of benzene (i.e. under Claus condition). The results reported here are with addition of 0% and 1% benzene to H2S/O2 flame. The results showed that H2S combustion caused H2S to decompose to a minimum mole fraction, which resulted in the formation of SO2 to a maximum mole fraction and then decomposed due to the formation of elemental sulfur, which is favorable under Claus condition. Combustion of H2S and benzene mixture favored the formation of H2 and increased the amounts of H2S at reactor exit after combustion. Benzene also caused faster decomposition of formed SO2 and formation of CO and COS. It is conjectured that benzene hinders the efficiency of Claus reactors and help increase emissions from sulfur recovery plants. These results provide significant insight on direct impact of benzene on the performance of Claus reactor for sulfur capture from acid gases. The results are also of practical value to designers and operators of sulfur plants and policy makers on emission control.