Technologies and innovations
Technologies. Hydrogen production from hydrogen sulfide
Hydrogen sulfide H2S is a gas with a characteristically pungent odor and is well-known to every one of us. Unlike its chemical counterpart – water, H2О, there is no practical use for hydrogen sulfide in human life. This “useless” and highly toxic substance should be removed from the exhaust gases and wastewater of industrial plants per sanitary standards.
There are tens of billions of tons of hydrogen sulfide in the interior and reservoirs of the Earth. In nature, hydrogen sulfide is formed during the biogenic decomposition of animal organisms and organic substances, since sulfur is part of all of the most important amino acids, and is formed as a result of the activities of sulfate-reducing bacteria. In addition, hydrogen sulfide emissions are part of volcanic processes. In industry, the main sources of hydrogen sulfide are oil and gas processing, coal gasification, biomass processing, etc.
Hydrogen sulfide utilization (more than 1,000 plants worldwide process up to 100 million tons / year of H2S) is carried out under the Claus method discovered back in the 19th century; as a result, the refinement products are water and solid sulfur. Thus, hydrogen H2 – a constituent element of hydrogen sulfide – is irreversibly lost in the form of water H2O, thereby eliminating the possibility of its use as environmentally friendly fuel.
However, few people know the other side of hydrogen sulfide as a chemical. The fact is that in 1887, S. N. Vinogradsky discovered the chemosynthesis (as opposed to photosynthesis which involves sunlight, the process known at that time) of organic matter from inorganic precursors – hydrogen sulfide H2S and carbon dioxide CO2. In this process, sulfur bacteria assimilating hydrogen sulfide use the energy of hydrogen sulfide to activate a chemically inert CO2 molecule. Thus, this “useless” hydrogen sulfide turned out to be the substance at the center of the natural process of chemosynthesis of organic matter from CO2, which laid the foundations for the origins of biological life on Earth, while H2S supplies hydrogen and energy. Chemosynthesis processes occur in nature at ambient temperature and pressure.
In 2006, Russian scientists discovered the hydrogen sulfide decomposition reaction which occurs on platinum catalysts at room temperature and forms hydrogen and a previously unknown substance – diatomic gaseous sulfur in the main triplet state. Subsequently, the scientists discovered catalysts and the process conditions that ensure hydrogen sulfide conversion of close to 100%, which made it possible to announce the discovery of a nature-like hydrogen sulfide decomposition process that produces hydrogen – an environmentally friendly fuel and a valuable chemical product.