Operating Experiences of Converting a Stretford to a LO-CAT(R) H2S Abatement System at Pacific Gas and Electric Company's Geysers Unit 15

Abstract

In January 1988, Pacific Gas and Electric Company (PG&E) converted the Stretford H2S abatement system at Unit 15 to use LOCAT H2S liquid redox process chemistry. The Stretford process is a vanadium based aqueous phase H2S scrubbing system, while the LOCAT technology uses a solution of chelated iron for H2S treatment. This paper describes the plant modifications required for the conversion. It characterizes the operating experience and H2S abatement performance over the past year of evaluating the process. Overall plant operability and H2S removal efficient of the LOCAT solutions at least as good as, or better than, Stretford. However, a plant considering the Stretford to LOCAT conversion needs to evaluate of its own situation the apparent redistribution of operating costs outlined in this report. One must also pay attention to the subtle changes in operating procedures required to use the LOCAT solution with existing Stretford process equipment.