Chemical Process Converts Sewer Gas Into Hydrogen

Researchers have developed a new chemical process that is able to turn gas created in the sewer system into hydrogen that can be used for fuel. The process converts hydrogen sulfide, commonly known as sewer gas, emitted from manure piles and inside the sewer pipes. Hydrogen sulfide is also created as a byproduct in some industrial processes, including oil refining, mining, and others.

One important aspect of the process created by the scientists at Ohio State University is that it requires relatively small amounts of energy, and the materials needed are relatively cheap. Key materials for the process include iron sulfide and trace amounts of molybdenum. Hydrogen sulfide is one of the most harmful gases produced by industrial processes and is harmful to the environment and the health of humans who encounter it.

Since the gas is harmful, researchers have worked on processes to convert it into something of use. Study researchers used a process created previously called chemical looping. The process adds metal oxide particles in a high-pressure reactor allowing them to burn fuel without requiring contact between air and fuel. When applied to hydrogen sulfide, the process is called SULGEN. However, the team found that pure iron sulfide didn't perform at the scale required for industrial processes during the research.

Researchers set out to identify other chemicals able to catalyze the reaction and eventually found that a trace amount of molybdenum with the iron sulfide would work for the desired reaction. In addition, both materials are relatively inexpensive and easy to obtain, making them suitable for industrial-scale conversion processes.

When hydrogen sulfide is converted into hydrogen fuel, it can be used as an alternative to oil and gas, which lessens the impact on the environment. However, project researchers say it's too soon to know if their process might be able to replace other similar technologies already on the market.