Low emission biogas also produces fertilizer

A Canadian chemical engineer has devised a product that transforms the waste generated by biogas production into fertilizer. Andrew White says his SulfaCHAR system eliminates chemical waste from the biogas process, while increasing renewable gas plants’ profitability and stopping the degradation to gas engines caused by hydrogen sulfide (H2S).

Biogas can help create electricity or be used as a replacement for natural gas and is often cited as a clean and carbon-neutral alternative to fossil fuels. Yet the decomposition process generates carbon dioxide and other dangerous, unpleasant smelling gases, causing an annual global clean-up bill of $1.2 billion USD.

According to White, “the greatest asset of biogas is that it’s capturing methane that would otherwise be going into the atmosphere where it’s 22 times worse than carbon dioxide for global warming, so a great story, but the same bacteria that make biogas also make hydrogen sulfide which is toxic, corrosive, and causes a lot of maintenance cost in the industry. So we really need to get it out of the gas so that gas can be used.”

He says SulfaCHAR is unique. “One of the unique aspects of what our process does is that it catalytically converts the sulfide into sulphur. Sulphur is a fertilizer product and because the feedstock we’re making it out of is a fiber that’s almost a compost when we’re done with it we’re left with a carbon compost that’s already in the fertilizer form, so we don’t have to any reprocessing. As soon as we take it out of the tanks where it’s been used for gas cleaning we can apply it directly to the fields,” said White.

White set up a University of Toronto research spinoff, CHAR Technologies, and says SulfaCHAR is the only product that effectively converts hydrogen sulfide into a fertilizer supplement rather than waste requiring disposal.

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