Ten Fraunhofer Institutes led by the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT have joined forces to work on the Fraunhofer lighthouse project “Electricity as a Raw Material”. Their aim is to develop and optimize processes that enable low-carbon power to be used to synthesize important base chemicals.
A shift away from petrochemicals – using a principle of nature
Plants are showing us how it’s done: they can synthesize a wide range of chemical substances from the carbon dioxide (CO2) in the atmosphere. Why shouldn’t industry do the same? In the past, nobody seriously followed up this idea because the underlying chemical reactions are very energy-intensive. However, the transition to a new energy economy and the weather-dependent decentralized generation of power mean that cheaper, low-carbon power will now be available in the medium term. This power could be used for the production of chemical products that up to now have mainly been produced using petroleum. That’s exactly the thinking being pursued in the “Electricity as a Raw Material” lighthouse project. Its researchers are developing new electrochemical processes, showcasing the technology and preparing it for integration into the German energy system.
The project consortium will develop two demonstration processes:
- The electrochemical production of ethene and assorted alcohols as the building blocks for a wide range of organic chemicals
- The electrochemical production of hydrogen peroxide (H2O2) from oxygen and hydrogen.
Producing base chemicals using electrochemical CO2 conversion
A great many products are manufactured in a series of complex and successive processes from what are known as base chemicals, which are obtained today in large quantities from fossil fuels. If petroleum and natural gas become scarcer and more expensive, as expected, then in the medium term there will have to be a change in the raw materials base – which also includes CO2 as a carbon-containing resource.
As a result, the focus is not on producing methane as a fuel or combustible, which falls under the header of “power to gas”. It’s true that Fraunhofer Institutes are pursuing this line of research as well, but the lead project is concerned with the synthesis of chemicals that cost more than natural gas. Such a technology would be relevant to the market more quickly.
The key to integrating new raw materials into chemical manufacturing is to ensure that the base chemicals produced can be integrated into the petroleum-based production structures of the chemical industry and do not involve a completely new synthesis tree or end products. This is what makes the production of alcohols and alkenes particularly interesting. Ethene, for example, is currently the most important base chemical – and it belongs to the category of substances which are manufactured today from petroleum. It is used, amongst other things, as the building block for the bulk plastic Polyethylene. A wide range of organic chemicals can be produced from short-chained alcohols, and higher alcohols are relatively expensive raw materials from which esters and acrylates (as well as other compounds) can be synthesized. One subproject is therefore aiming to develop electrochemical processes for making alkenes and alcohols from CO2.
Producing hydrogen peroxide as an environmentally friendly and frequently used oxidizing agent
CO2 does not always have to be the building block if chemicals are produced electrochemically. Another subproject is using the same principle to map the decentralized production of hydrogen peroxide (H2O2) from oxygen and hydrogen. H2O2 is used as an environmentally friendly, selective and also highly active oxidizing agent in a wide range of chemosynthetic oxidization reactions. In comparison to other oxidizing agents, some of which generate critical waste products, water is the only reaction product when H2O2 is used for oxidization. Perhaps that’s why H2O2 is a frequently used oxidizing agent for bleaching pulp and paper. H2O2 is currently produced in a way that incurs considerable associated costs due to the high safety requirements that govern how it may be processed, stored and transported. Direct synthesis from molecular oxygen and hydrogen would be an inexpensive, safe and clean alternative that end users could carry out on a small scale on their own premises.
The aim of the subproject is to develop a demonstration process for the continuous electrochemical production of hydrogen peroxide. Production is on a kilogram scale, and its upstream integration is achieved on a technical scale according to the paradigm of pulp bleaching and selective oxidization (phenol synthesis).
Significance and prospects
Assuming that both the share of renewables in the German power system as well as the amount of surplus electricity will have increased significantly in no more than 15 years’ time, then it follows that it will soon be possible to generate power more cheaply and with substantially lower CO2 emissions. This is a prerequisite if manufacturing in the future is to be able to rely more heavily on “electricity as a raw material” to achieve sustainability targets.
Professor Eckhard Weidner, director of the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, which is coordinating the project, emphasizes how important this approach is for the whole economy: “Expert analysis tells us that the transition to a new energy economy also has to be squared with the needs of energy-intensive industries in order to make stable growth possible in the long term. So, we have to succeed in linking together the energy system and the chemical manufacturing system. Electrochemical processes are the enabling technologies that can provide the technological basis for establishing the link between these systems.”
The Fraunhofer Institutes collaborating in this lead project have already given extensive thought to how its findings can be put to lasting use. They intend to construct permanent value chains in the market so that in ten years or so Fraunhofer will be seen as a complete service provider for electrochemical research and development. The institutes have already established contacts with companies from the key industrial sectors and made plans for a public dialogue. The “Electricity as a Raw Material” lighthouse project is set to run for a period of three years.