Case History: Controlling H2S Emissions from Landfill Gas
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A major US waste handling company operates a large landfill in Florida, and in 1992, when Hurricane Andrew struck southern Florida, the landfill saw a huge increase in the amount of C&D waste. Shortly after this, the levels of H 2 S started dramatically rising. This company evaluated several technologies for the removal of H2S, which was estimated to be as high as 5000 ppmv, with up to 2-3 tons/ day H2S being removed with the landfill gas. This presented a problem, since the landfill planned to generate up to 11 MW power from 3-5 turbine powerplants by burning this landfill gas. All combustion equipment has a certain tolerance for H2S and its corrosive combustion products, but turbines have the lowest tolerance. The equipment at the facility could only tolerate 100 ppmv inlet H2S, well below the current levels in the landfill gas.
Short project completion was essential in the decision, and the project was awarded to Gas Technology Products LO-CAT® Process. The LO-CAT Process is a proprietary, chelated iron liquid redox process that removes the H2S from landfill gas, converting it to solid elemental sulfur, that can be used as an additive for fertilizer. There are 150 licensed LO-CAT Units worldwide. A LO-CAT H2S Oxidation System, was designed and delivered in only 22 weeks. The unit was commissioned in 1994, and has been operating since, producing gas with less than 100 ppmv H2S.