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Title: Upstream H/sub 2/S removal from geothermal steam. Final report

Technical Report ·
DOI:https://doi.org/10.2172/5687735· OSTI ID:5687735

The purpose of this project was to evaluate a new heat exchanger process as a method for removing hydrogen sulfide (H/sub 2/S) gas from geothermal steam upstream of a power plant turbine. The process utilizes a heat exchanger to condense geothermal steam so that noncondensable gases (including H/sub 2/S) can be removed in the form of a concentrated vent stream. Ultimate disposal of the removed H/sub 2/S gas may then be accomplished by use of other processes such as the commercially available Stretford process. The clean condensate is reevaporated on the other side of the heat exchanger using the heat removed from the condensing geothermal steam. The necessary heat transfer is induced by maintaining a slight pressure difference, and consequently a slight temperature difference, between the two sides of the heat exchanger. Evaluation of this condensing and reboiling process was performed primarily through the testing of a small-scale 14 m/sup 2/ (150 ft/sup 2/) vertical tube evaporator heat exchanger at The Geysers Power Plant in northern California. The field test results demonstrated H/sub 2/S removal rates consistently better than 90 percent, with an average removal rate of 94 percent. In addition, the removal rate for all noncondensable gases is about 98 percent. Heat transfer rates were high enough to indicate acceptable economics for application of the process on a commercial scale. The report also includes an evaluation of the cost and performance of various configurations of the system, and presents design and cost estimates for a 2.5 MWe and a 55 MWe unit.

Research Organization:
Coury and Associates, Lakewood, CO (USA)
OSTI ID:
5687735
Report Number(s):
EPRI-AP-2100; ON: DE82901293
Country of Publication:
United States
Language:
English