Fraunhofer TechFlash: Fraunhofer’s Expertise for the Hydrogen Age (Part I)

Climate change has turned the spotlight to the subject of sustainability. Hydrogen delivers a powerful answer to many of the questions raised by this debate. For this reason, it looks set to become a key molecule for the transition to a sustainable energy economy and the transition from fossil-based to renewable resources. There is an evident need for hydrogen technology. In the power sector, for example, we require flexible ways of storing surplus electricity, so that this can then be fed back into the grid at times when solar or wind energy are unavailable. If climate targets are to be met, we must continue to expand the renewable generation of electricity. Yet this expansion only makes sense in conjunction with the development of hydrogen-based technologies.

From 2021, for example, the steel industry will be using hydrogen to reduce its CO2 footprint. By 2050, it should be possible to produce steel on a CO2-neutral basis. Moreover, if CO2 is removed from highly concentrated waste gases and converted into basic chemicals such as methanol by means of hydrogen, it will not only improve the climate impact of industrial processes but also mark the beginning of a new form of production that is no longer dependent on fossil-based resources. In the long term, it should also be possible to remove CO2 from the atmosphere, combine it with hydrogen and thereby create a source of raw materials that fills the gap in the global carbon cycle. Hydrogen will also help achieve climate neutrality in the transport sector, especially in areas where directly electrified propulsion is not an option.

One promising area for the use of hydrogen is in production processes that generate large volumes of carbon dioxide. Here, hydrogen offers various ways of defossilizing the production chain. The key task is to make this switch both economical and sustainable.

Hydrogen enables manufacturing to cut CO2 emissions

Fraunhofer UMSICHT and ISE working on a defossilization strategy for steel production in collaboration with the consortia partners. The Carbon2Chem® project takes carbon gases produced in blast furnaces and coking plants and converts them into basic chemicals such as methanol and urea. These chemicals can then be used to produce fuels, fertilizers or plastics. This enables a substitution of fossil-based feedstocks in the chemical industry as well as the elimination of substantial quantities of fossil-based carbon. Among other tasks, researchers from UMSICHT are working on models to simulate the integrated production systems that emerge from this new approach. Key questions here include the impact on the overall system – for example, how the manufacture of chemicals in a steelworks will affect the entire production system. In addition, researchers are developing adsorption and plasma technologies to purify the waste gases generated during steel production, and to test the functionality and viability of the catalysts used for chemical synthesis. The process is now working on a pilot scale and could be ready for rollout in production plants by as early as 2025, thereby helping the steel industry to reduce its carbon footprint by means of hydrogen. Work is also underway to ensure a swift transfer to other sectors such as the cement industry.
The researchers from Fraunhofer IKTS are developing an integrated process for the commercial exploitation of industrial waste gases and wastewater from a lime works. The objective is to produce useful chemicals. This process features a combination of high-temperature co-electrolysis, CO2 separation by means of special ceramic membranes, and the Fischer-Tropsch synthesis with a newly developed, scalable reactor concept. This produces synthetic waxes, which can then be used as lubricants or as base materials for the production of cosmetics. Fraunhofer researchers are also working on process development. This involves simulating and enhancing the entire process. By coupling the individual process steps at the lime works, it is also possible to use by-products from the Fischer-Tropsch synthesis in the combustion process, which creates options for greater flexibility.

In a related area, mine water heavily contaminated with minerals and sulfates can be treated with the RODOSAN process, which was developed by Fraunhofer IKTS. Here, three things happen in parallel: hydrogen is recovered from the mine water to serve as an energy carrier; iron in the mine water is reduced and thereby recovered; and toxic substances, especially sulfur, are concentrated and recovered for use in fertilizers. Between 45 and 70 percent of the sulfates contained in the mine water can be removed in this way. A pilot plant with a capacity of 6 cubic meters per hour is available for the purposes of technical analysis and process optimization.

P2X: from green power to hydrogen, fuel and gas

The transition to a sustainable energy system poses a fundamental question. If renewable power cannot be fed into the grid immediately, how can it be stored at the place where it is generated? In other words, how can locally generated power be made available in order to cover fluctuating demand? This is where P2X technology enters the equation. Here, renewable power is used for electrolysis, and the hydrogen thereby produced is stored and then converted into chemicals, fuel or gas. This process is known as power-to-chemicals, power-to-fuel or power-to-gas. An example of a power-to-gas application is the ICOCAD project from Fraunhofer IMM. Using an innovative reactor system, CO2 recovered from biogas plants and biorefineries is converted to methane through the addition of hydrogen produced via the electrolysis of water. At present, researchers are developing new plant designs, conducting tests on a pilot scale and installing a reactor in an existing plant. In a related project, they are also working on catalysts for this process that are long-lasting and resistant to poisoning and coking. The modular design of the reactor means that it can be easily adapted to the size and specifications of the carbon dioxide and hydrogen sources.

Increasing electrolyzer capacity

Regardless of which P2X or other hydrogen technology is used, it is always based on hydrogen produced by means of electrolysis with renewable power. Fraunhofer IMWS is therefore building a test and experimentation infrastructure for electrolyzers in the megawatt range – up to a scale of 5 megawatts – at the Leuna Chemical Park. Four project stations, each with space for two or three 40-foot containers, are to be available from 2020. Project partners will be able to reconstruct the entire process chain, including downstream processes such as methanol synthesis. Researchers will assess the projects, supervise test equipment, run various test cycles and evaluate the results. The hydrogen generated by these projects can be fed into the 150-kilometer pipeline that connects various chemical parks in the region.

Hydrogen from biogenic sources

Biogenic residues and waste are another potential source of green hydrogen. Fraunhofer UMSICHT has developed a process for generating hydrogen from feedstocks based on biomass. TCR® is a thermo-chemical conversion process that yields an extremely hydrogen-rich synthesis gas. Moreover, the stable, carbonized solid that is produced in this process can also be gasified in order to generate hydrogen. The TCR® process is currently being demonstrated in the EU project ToSynFuel, which has a throughput of 12 metric tons of residue a day.