New system converts CO2 from boilers into fuel methane

May 28. () –

Researchers from Japan and Poland have created a method to convert CO2 from small boilers into methane, with a reactor design that evenly distributes the CO2 feed.

Reducing carbon emissions from small-scale combustion systems, such as boilers and other industrial equipment, is a key step towards building a more sustainable, carbon-neutral future. Boilers are widely used in various industries for essential processes such as heating, steam generation and power production, making them major contributors to greenhouse gas emissions.

Boilers are usually quite efficient. As a result, it is difficult to reduce CO2 emissions simply by improving combustion efficiency. Researchers are therefore exploring alternative approaches to mitigate the environmental impact of CO2 emissions from boilers. A promising strategy for this purpose is capture the CO2 emitted by these systems and convert it into a useful product, such as methane.

To implement this strategy, a specific type of membrane reactor, called a distributor-type membrane reactor (DMR), is needed that can facilitate chemical reactions and separate gases. While DMRs are used in certain industries, their application to convert CO2 to methane, especially in small-scale systems such as boilers, has remained relatively unexplored.

This research gap was addressed by a group of researchers from Japan and Poland, led by Professor Mikihiro Nomura of the Shibaura Institute of Technology in Japan and Professor Grzegorz Brus of the AGH University of Science and Technology in Poland. Their findings were published in the Journal of CO2 Utilization.

The team carried out a two-pronged approach to the problem using numerical simulations and experimental studies to optimize reactor designs for the efficient conversion of CO2 from small boilers to methane. In their simulation, the team modeled how gases flow and react under different conditions. In turn, this allowed them to minimize temperature variations, ensuring that energy consumption is optimized while methane production remains reliable.

The team further discovered that, unlike traditional methods that funnel gases to a single location, a distributed feed design could spread the gases into the reactor rather than sending them from a single location. This, in turn, results in better distribution of CO2 throughout the membrane, preventing any area from overheating. “This DMR design helped us reduce temperature increases by about 300 degrees compared to traditional packed bed reactor“explains Professor Nomura.

Beyond the distributed feed design, the researchers also explored other factors that influence reactor efficiency and found that a key variable was the concentration of CO2 in the mixture. Changing the amount of CO2 in the mixture affected the efficiency of the reaction. “When the CO2 concentration was around 15%, similar to what comes out of the boilers, the reactor produced methane much better. In fact, it could produce around 1.5 times more methane compared to a normal reactor that only runs on pure CO2.“, highlights Professor Nomura it’s a statement.

Additionally, the team investigated the impact of reactor size and found that increasing reactor size made hydrogen more readily available for the reaction. However, a trade-off had to be considered, as the benefit of greater hydrogen availability required careful temperature management to avoid overheating.

The study therefore presents a promising solution to the problem of addressing a major source of greenhouse gas emissions. By using a DMR, low concentration CO2 emissions can be successfully converted into usable methane fuel. The benefits obtained are not limited only to methanation, but can also be applied to other reactions, making this method a versatile tool for the efficient use of CO2 even in homes and small factories.