The new method makes it possible to produce hydrogen in several stages. First, water vapour and a catalyst are pumped into the well, followed by air or pure oxygen, thanks to which natural gas is combusted right inside the formation. During the combustion process, natural gas turns into a mixture of carbon monoxide and hydrogen: carbon monoxide produces carbon dioxide, which remains inside the formation, whereas hydrogen is extracted from the well using a membrane that does not allow other reaction products to pass through. As a result, all emerging gases except hydrogen, including carbon monoxide and carbon dioxide, remain forever preserved underground, making it possible to minimise the carbon footprint.
The new technology underwent testing in a reactor, which made it possible to recreate gas formation conditions, including pressure 80 times higher than the atmospheric pressure. The researchers loaded crushed rocks into the reactor and then used pumps in order to pump methane (the main component of natural gas), water vapour, catalyst and oxygen into the reactor. An analysis of the gas composition in the reactor showed that a high amount of hydrogen – 45% of the total volume of gases – was formed at a temperature of 800 degrees Celsius with large volumes of water vapour supplied to the reactor (in a ratio of 4 to 1 to the volume of natural gas). At the same time, the temperature of 800 degrees Celsius was easily achieved during the combustion of natural gas, i.e., no additional energy sources were required to maintain it.
The yield of hydrogen during the experiment also depended on the composition of the rocks. If aluminum oxide was used, which did not react with the substances surrounding it, hydrogen yield was at 55%. In turn, the use of natural rocks saturated with chemically active minerals that entered into side reactions with the components of the gas mixture led to a lower hydrogen yield.
“All stages of the proposed process are based on well-proven technologies that had not previously been adapted to extract hydrogen from a real gas formation… In the future, we plan to test our methodology in practice, using the example of gas fields,” Elena Mukhina, leader of the study and senior researcher at Skoltech, is quoted by the Russian Science Foundation.
