Unit 14 / Sulphur Springs H2S Abatement Process Screening and Stretford Improvements Study--Part 3

Abstract

Presented in this report are the results of Part 3 of a three-part study performed in 2007. The major goal of the study was to improve the primary H2S abatement system at the Sulphur Springs (Unit 14) Power Plant owned by Calpine Corporation and located at The Geysers. The existing Stretford system is approximately 30 years old and is now under-loaded due to reduced NCG, which was a result of Geysers Recharge water injection. The following three questions were investigated in the 2007 study: Part 1) Is replacement of the existing Stretford system economically advantageous, given the availability of modern, environmentally-friendly gas treatment technology that could handle the current low sulfur load with a much smaller footprint and less parasitic power load? [An article that was focused on Part 1 was presented at the 2010 GRC Annual Meeting in Sacramento, CA (Benn et al., 2010).] Part 2) In lieu of replacing the Stretford system, what operational mprovements can be made to the existing system to reduce the total cost of treatment? [An article that was focused on Part 2 was presented at the 2011 GRC Annual Meeting in San Diego, CA (Benn et al., 2011).] Part 3) What physical modifications can be made to the Stretford system to reduce process shutdowns caused by sulfur plugging? [Part 3 is the basis of this article.] The primary conclusions of the study are: i) every alternative technology considered proved to have a higher total treatment cost than continuing with the existing Stretford unit, even if no improvements are made, and even though it is operating at ~10% of original design loading; and ii) significant reductions in total treatment cost should be possible by implementing several recommended improvements described in Part 2 and Part 3 of this work.