Coal is not only an important fuel for electricity generation in the Rhine region. The chemical industry also uses coal to produce vital essential compounds. But once coal is phased out, these materials will need to come from other renewable sources. One of these is carbon monoxide, also known as CO, which is necessary for the formation of acetic acid and various polymers.
Electrochemical Conversion of Carbon Dioxide to Carbon Monoxide
For this, researchers at the Forschungszentrum Jülich are developing technology that is environmentally friendly and based on renewable energy. greenhouse gas CO2 It is electrochemically converted to carbon monoxide, which is used as fuel. Now overcoming a major hurdle, the researchers have created a scalable cell stack for large-scale applications.
The study is a component of the iNEW structural transformation project, which aims to use renewable-based processes to promote employment growth and job retention in the Rhine region.
“The industry typically produces CO locally on a large scale. It is difficult to transport because it is a toxic and highly flammable gas,” explains Maximilian Quentmeier, a graduate student at the Jülich Center for Energy and Climate Research (IEK-9). Typically this gas is produced by burning coal with insufficient oxygen supply.
But as coal is phased out, new procedures will be required to replace it. CO will continue to be essential as an essential chemical in the future. Among other things, it is necessary for the creation of polycarbonates and polyurethanes, which are used, for example, to produce insulating panels and eyeglass lenses.
Maximilian Quentmeier, CO with boss Bernhard Schmid2He's working on a procedure known as 'to-CO electrolysis'. The method uses a device known as a gas diffusion electrode, which has a porous electrode next to a liquid or solid electrolyte on the front and is fed with CO2 on the back. The electrode connects the two environments and the electric current, resulting in the formation of "green" carbon monoxide, CO.
Potentially damaging to the climate
This method not only benefits the chemical industry, but also helps protect the environment. “CO2 electrolysis plants will operate in a climate-neutral manner if powered by renewable energy. It could even be climate neutral if carbon dioxide is obtained directly from the environment, such as through air harvesting or biogas production,” adds Bernhard Schmid.
In general, the method atmospheric CO2 can actively reduce its concentration. According to Bernhard Schmid, renewable plastics of the future will theoretically act as a carbon sink, like wood.
Quentmeier and Schmid have reached an important milestone on the road to commercialization. By making numerous modifications and replacing parts, they were able to turn the single cell into a batch-type electrolyzer and tested it in a series of performance tests. The findings were recently published in ACS Sustainable Chemical Engineering.
The cells are stacked tightly together in a heap. Producing a single large cell is more expensive than producing a batch of smaller cells. “There are several factors to consider when creating a stack from a cell. For example, gas reaction cells have several chambers that are not normally supported in laboratory environments. The cells of a stack must tolerate compression stress while remaining permeable,” explains Maximilian Quentmeier.
The Jülich researchers optimized the design of the electric current collector and gas flow field under the assumption of realistic process conditions. The electrolyte cavity is structurally supported by a solid flow passing through the polymer electrolyte composed of ionically conductive synthetic resin instead of the conventional liquid electrolyte.
The electrolyte chamber between the membrane and the anode was also completely eliminated by the researchers thanks to an innovative anode design. The bipolar plate connecting the two cells serves as the cathode and anode of the stack, that is, the positive and negative electrodes of the nearby cells.
The stack achieves 30% efficiency in the current experimental setup using modular components that are not optimized for efficiency. Institute President Prof. Rüdiger-A. Eichel says: “This is a very promising result for this kind of process that already works below 100°C.
“The architecture of the plant is quite simple compared to, for example, high-temperature co-electrolysis and produces pure CO instead of syngas, making it even easier to process for many applications. As a result, industrial enterprises in the Rhine region can save on transportation costs by decentralizing the platform chemical CO.” According to Eichel. The cell stack will now undergo further research and efficiency improvements to reach the point where it is fully ready for mass production.
Source: techxplore.com/news – Forschungszentrum Juelich
Günceleme: 18/03/2023 22:54