Sewer Gas Sees Conversion to Hydrogen Fuel

Sewer Gas Sees Conversion to Hydrogen Fuel
Hydrogen storage tank concept in beautiful morning light. 3d rendering.

Something smells like progress, and it is a new use for sewer gas. With the ever-growing push to alternate fuels and clean-burning energy, scientists from various locations are pioneering to meet the demands of activists and government. Answering the call, scientists have devised a process to convert nasally offensive gas, known as hydrogen sulfide, into the clean-burning and efficient hydrogen fuel.

The American Chemical Society provides for the ACS Sustainable Chemical Engineering Journal, where this conversion process was recently the subject of an article explaining the specifics. Hydrogen sulfide can be derived from multiple sources, including manure piles, sewer pipes, and it also presents itself as a byproduct from industries including oil and gas, paper production, and even mining. 

Hydrogen sulfide is a highly toxic gas that can be menacing. Not only does it corrode piping, it can be lethal to those who encounter it. But, scientists have determined that the process of harnessing the hydrogen sulfide uses minimal energy, which pleases those wishing to reduce their carbon footprint. Materials used in the process include chemical iron sulfide with a small amount of molybdenum serving as an additive. As a result, these materials do not break the bank leaving oil and gas financialists pleased.

“Hydrogen sulfide is one of the most harmful gases in industry and to the environment,” said Lang Qin, co-author of the study and research associate in chemical and biomolecular engineering at Ohio State University. “And because the gas is so harmful, a number of researchers want to turn hydrogen sulfide into something that is not so harmful, preferably valuable.”

This current research coalition previously developed the Chemical Looping process, which involves the addition of metal oxide particles into high-pressure reactors to burn fuels without seeing the direct mixture or contact of air and fuel. This looping process was first applied on coal and shale gas for the conversion of fossil fuels to electricity without sending carbon dioxide into the atmosphere. Iron oxide was initially used to break down the fossil fuels.

Having developed the SULGEN process, which is the conversion of hydrogen sulfide into hydrogen, researchers discovered that the iron sulfide did not fare well at the grand levels dictated for industrial use. Qin indicated that as a result, the team has been attempting to identify inexpensive alternative chemicals that could serve as a transformation catalyst in greater quantities. The introduction of molybdenum into the iron sulfide could be the solution the team has been seeking.

The benefits of such work include the fact that the material is easily acquired at a more cost-effective price. Large-scale operations are more realistic when realizing such ease and cost-efficiency. 

“It is too soon to tell if our research can replace any of the hydrogen fuel production technologies that are out there,” said Kalyani Jangam, lead author of the study and graduate student working at Ohio State’s Clean Energy Research Laboratory. “But what we are doing is adjusting this decomposition process and making a valuable product from that.”

According to their most recent study, research reflects that the molybdenum improves the breakdown process of hydrogen sulfide and divides it into two parts being hydrogen fuel and sulfur. While stages remain early in the scientific process and the process was successful in the laboratory, additional tests at the industrial level will be needed.

“The big picture is we want to solve the harmful gas issue, and we thought that our chemical looping process would allow that,” said Qin. “And here, we have found a way to do it in the lab that creates this value-added hydrogen fuel.”


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