When it burns, you know, it only emits water vapor. This may be why hydrogen could be the healthier alternative to fossil fuels such as oil and natural gas, responsible for the emission of carbon dioxide and climate change. This is if the production of this "green fuel" were not still difficult and expensive. Now, however, a group of Russian scientists has found an ingenious way to extract hydrogen directly from natural gas deposits, exploiting the same hydrocarbons that contain large quantities of this element at a molecular level. A revolutionary process that could change the face of the energy of the future.
Steam, catalyst and oxygen: the ingredients of the green recipe
Elena Mukhina, Ph.D., senior researcher at Skoltech in Moscow and leader of the study published on Fuel (I link it here), is proud of the result. “All stages of the process are based on well-established technologies, which have not previously been adapted for hydrogen production from real gas fields,” she explains.
We have demonstrated that our approach can help convert hydrocarbons into 'green' fuels in the reservoir environment with an efficiency of up to 45%. In the future, we plan to test our method on large gas reservoirs.
But how exactly does this process work?
First of all, steam and a catalyst are injected into the reservoir well. The catalyst will then be used to separate the hydrogen from the natural gas components. Subsequently, air or pure oxygen are pumped in to ignite the gas directly in the reservoir.
Assisted by steam and the catalyst, the natural gas burns and converts into a mixture of carbon monoxide and hydrogen. The carbon dioxide that forms from carbon monoxide remains trapped in the reservoir, without contributing to the greenhouse effect.
In the last stage, hydrogen is extracted from the well through a membrane that blocks other combustion products, leaving carbon monoxide and carbon dioxide permanently trapped underground.
Hydrogen from gas fields, laboratory tests: promising results
The team tested this process in laboratory reactors that simulated the real environment of a gas field. “We put crushed rock into the reactor and then pumped in methane, the main component of natural gas, together with steam and catalyst, and then oxygen,” says the researcher. “The pressure inside the reactor was maintained at a level typical of gas fields, eighty times higher than atmospheric pressure.”
As the experiment progressed, the team analyzed the composition of the gases in the reactor to evaluate the efficiency of converting methane to hydrogen. It turned out that most of the hydrogen, 45% of the total gas volume, was formed at 800°C with large amounts of steam injected into the reactor.
To make the reaction as efficient as possible, there should be four times more steam than natural gas. “We chose the temperature of 800°C because it is easily achievable in the combustion of natural gas and does not have to be maintained artificially,” explains the researcher.
The importance of the rock: many deposits, many scenarios
The hydrogen yield also depends on the composition of the rock. “For example, in experiments with porous alumina, the hydrogen yield reached 55%,” notes Dr. Mukhina.
The higher efficiency in this case is explained by the fact that alumina is inert, i.e. it does not react with surrounding elements. Natural rock contains other, more active minerals that can react with components of the gas mixture and affect the hydrogen yield.
This means that each gas field will have different characteristics and will require careful analysis before this process can be applied on a large scale. But the results obtained so far are promising and pave the way for a new era of clean energy.
Towards a hydrogen future: challenges and opportunities
The transition from fossil fuels to hydrogen will not be immediate or without obstacles. On the contrary. It will still take a lot of research and development work to optimize the process and adapt it to different conditions in natural gas fields. Not to mention the infrastructure for the transport and distribution of hydrogen, which is currently still limited.
The potential of this technology, however, is enormous. If we can produce green hydrogen on a large scale directly in gas fields, we could dramatically reduce carbon dioxide emissions and slow climate change. Hydrogen could become a versatile and applicable energy source in many sectors, from transport to the production of electricity.
The work of the Skolkovo team is an important step in this direction. Hydrogen extracted directly from natural gas deposits could be a trump card.
