AirScience Technologies offers two desulfurization processes. ISET Iron chelate process for high inlet hydrogen sulfide concentrations. Dry scrubbing catalyst for low inlet hydrogen sulfide concentrations. In cases where hydrogen sulfide concentrations of less than 100 ppmv are required, a dry scrubbing catalyst stage is required.
The process is recommended for reduction of high hydrogen sulfide concentrations (>1000ppmv) to concentrations of 100ppmv. To achieve hydrogen sulfide concentrations in the <5ppmv, a second stage consisting of a dry scrubbing catalyst will be required.
The process consists in passing the hydrogen sulfide charged biogas through a series of mass transfer towers where the proprietary iron chelate liquor will interact with the hydrogen sulfide and remove it from the gas phase.
The spent liquor is then processed in a liquor regeneration tower where the iron chelate liquor is regenerated and the sulfur precipitated as elemental sulfur which will then be separated by filtration.
The process operates at atmospheric pressure, at ambient temperature and has no liquid discharge. The only process discharge is the sulfur cake which has a certain humidity content.
The process operates continuously and only requires a periodical inspection and cleaning of some internal components to ensure optimum efficiency and performance.
The DSC process is based on the property of iron sponge to convert to iron pyrite in the presence of hydrogen sulfide.
To enhance the reactivity of the active product as well as the activity of the whole pellets and not only the external surface, the active media is enhanced by certain additives defined as catalysts.
The process consists in passing the hydrogen sulfide charged biogas through a tower filled with the required amount of active media to ensure the required hydrogen sulfide outlet concentration level as well as the expected life of the media.
Once spent, the media will be disposed of in a regular solid waste landfill for non hazardous waste.
Generally, two towers are installed in parallel, sized for the full gas flow passing through one tower. This arrangement allows for continuous operation even when the media in one tower has to be replaced.
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