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Title: Reaction of Hydrogen Sulfide with Oxygen in the Presence ofSulfite

Commonly, abatement of hydrogen sulfide emissions from a geothermal powerplant requires that hydrogen sulfide dissolved in the cooling water be eliminated by chemical reaction. Oxidation by atmospheric oxygen is the preferred reaction, but requires a suitable catalyst. Nickel is the most potent and thereby cheapest catalyst for this purpose. One Mg/L nickel in the cooling water would allow 99% removal of hydrogen sulfide to be attained. A major drawback of catalytic air oxidation is that colloidal sulfur is a major reaction product; this causes rapid sludge accumulation and deposition of sulfur scale. The authors studied the kinetics and product distribution of the reaction of hydrogen sulfide with oxygen, catalyzed by nickel. Adding sodium sulfite to the solution completely suppresses formation of colloidal sulfur by converting it to thiosulfate. The oxidation reaction is an autocatalytic, free radical chain reaction. A rate expression for this reaction and a detailed reaction mechanism were developed. Nickel catalyzes the chain initiation step, and polysulfidoradical ions propagate the chains. Several complexes of iron and cobalt were also studied. Iron citrate and iron N-hydroxyEDT are the most effective iron based catalysts. Uncomplexed cobalt is as effective as nickel, but forms a precipitate of cobalt oxysulfide and ismore » too expensive for practical use.« less
Authors:
;
Publication Date:
OSTI Identifier:
909494
Report Number(s):
LBL--11377
TRN: US200722%%1109
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Technical Report
Research Org:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org:
USDOE Director, Office of Science
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; HYDROGEN SULFIDES; OXIDATION; NICKEL; CATALYTIC EFFECTS; GEOTHERMAL POWER PLANTS; COOLING SYSTEMS; ADDITIVES; WATER TREATMENT; CHEMICAL REACTION KINETICS