Electrochemical removal of hydrogen sulfide from multicomponent gas streams

Miscellaneous · Fri Jan 01 00:00:00 EST 1988

OSTI ID:6798956

Weaver, D W

Development of an electrochemical membrane separator capable is the subject of this investigation. The electrochemical H{sub 2}S removal cell has been demonstrated previously. The cell consists of a molten salt electrolyte membrane sandwiched between two porous gas diffusion electrodes. Hydrogen sulfide is electrochemically reduced at the cathode. Sulfide ions are then transported across the membrane to the anode, where oxidation takes place. Development of electrode materials and demonstration of process performance at conditions of commercial interest were the goals of this investigation. Transition metals and ceramic metal oxides were used as electrodes in experimental cell tests. Transition metal cathodes, stable as metal sulfide compounds, were generally highly conductive, showed rapid kinetic rates for H{sub 2}S removal, and allowed high current density at low overpotential. Cobalt sulfide appears to have the best combination of physical and electrical properties for use as either the anode or cathode. Strontium doped lanthanum chromite, La{sub .8}Sr{sub .2}CrO{sub 3}, showed excellent physical and chemical stability in the cell environment, but resulted in about 2.5 times higher polarization than cobalt electrodes at a given current density. Over 95% H{sub 2}S removal from a stream of H{sub 2}, CO{sub 2}, H{sub 2}O, CO, N{sub 2} and H{sub 2}S was repeatedly achieved at temperatures of 650{degree}C or higher. Although selective H{sub 2}S removal is theoretically possible, diffusion of H{sub 2} through the membrane changed the net cell reactions and resulted in electrochemical removal of CO{sub 2} and H{sub 2}O along with H{sub 2}S. Economic analysis shows that this process offers substantial energy and capital cost advantages over existing H{sub 2}S removal technologies if selective removal is attainable.

• Research Organization: Georgia Inst. of Tech., Atlanta, GA (USA)
• OSTI ID: 6798956
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
COAL GAS
DESULFURIZATION
ELECTROCHEMICAL CELLS
ELECTRODES
PERFORMANCE TESTING
MATERIALS TESTING
HYDROGEN SULFIDES
REMOVAL
CARBON DIOXIDE
CERAMICS
CHEMICAL REACTION KINETICS
COAL GASIFICATION
COBALT SULFIDES
CURRENT DENSITY
DIFFUSION
ECONOMIC ANALYSIS
EFFICIENCY
ELECTRICAL PROPERTIES
HYDROGEN PRODUCTION
LANTHANUM COMPOUNDS
MEMBRANES
MIXTURES
MOLTEN SALTS
OXIDATION
PHYSICAL PROPERTIES
POROSITY
POROUS MATERIALS
REDUCTION
SEPARATION PROCESSES
STRONTIUM
SULFUR
ALKALINE EARTH METALS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
COBALT COMPOUNDS
DISPERSIONS
ECONOMICS
ELEMENTS
FLUIDS
GASES
GASIFICATION
HYDROGEN COMPOUNDS
KINETICS
MATERIALS
METALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
REACTION KINETICS
SALTS
SULFIDES
SULFUR COMPOUNDS
TESTING
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
010402* - Coal
Lignite
& Peat- Purification & Upgrading