Charting the course to green steel with hydrogen

17.11.2021 | Salzgitter Flachstahl GmbH


The first steps towards new production processes in the steel industry are already demanding a great deal of inventiveness and pioneering spirit.
It's not every day that an industry is virtually reinventing itself. But the global climate targets are demanding that some industries to do precisely that - because the efforts to reduce CO2 emissions are defining new framework conditions for them. The automotive industry, for example, will be increasingly turning out electric vehicles in the future. The steel industry, on the other hand, is pushing ahead with the decarbonization of its production processes; after all, the iron and steel sector is responsible for around 30 % of industrial CO2 emissions in Germany.
The steel industry has embarked on the transition towards green steel on its own initiative. Initially, there seemed to be several possible solutions. Consideration was given to storing the CO2 released during the classic crude steel production process in the ground or to chemically converting it, or processing CO2 into other materials. It did not take long, however, for another solution to emerge as the more sustainable course. One that Salzgitter AG had adopted right from the very outset with the SALCOS® - SAlzgitter Low CO2 Steelmaking project: If the emission of greenhouse gases is avoided, no one has to think about their disposal. Instead of having to search for solutions to a problem, preventing the problem from arising in the first place is an elegant as well as a sensible approach.

 

Structural changes necessary

The requisite technology already exists in the form of direct reduction and no longer needs to be invented. To put it briefly, this process in crude steel production extracts the iron from with the aid of hydrogen and disepenses with coal entirely. The hydrogen is obtained from natural gas or from water by means of electrolysis. Direct reduction plants are already in operation in countries where natural gas is available at favorable costs.
Consequently, the pioneering activities are not in the development of the basic technical process for future steel production, but in the integration of such a process route into existing steelworks, the use of large shares of hydrogen in the direct reduction plant and the establishment of a climate-neutral hydrogen economy, as well as the link between the industry and the energy sector - also referred to as sector coupling. This is because hydrogen can only replace the fossil fuel coal in crude steel production in a climate-neutral manner if sufficient electricity from renewable energies is available for the electrolyses. The wind turbines that have been put in place in and around the Salzgitter Flachstahl GmbH steelworks already illustrate this change. The realization of the "Windwasserstoff Salzgitter - WindH2" project also represented pioneering achievement in other respects. This is because the approval of a wind farm at an industrial site that is subject to the Major Accidents Ordinance placed high demands on the project management and required special precautionary measures. Accordingly, the wind farm is now regarded as a reference project with a "lighthouse" effect – as the first industrial sector coupling in Germany.

 

Multiple tasks for change

In addition to the multitude of regulatory adjustments, sector coupling and the development of a hydrogen economy call for many new technical solutions in detail - for efficient electrolysis processes as well as for the transport and storage infrastructure of hydrogen.
The necessary national distribution infrastructure for hydrogen is another area for innovations. Germany's well-developed natural gas pipeline network is being examined with regard to its suitability for hydrogen transport, as is the need for the conversion or expansion of hydrogen pipelines.
The special chemical and physical properties of hydrogen also require new monitoring procedures to ensure the safety of the plants for the production, transport, storage and use of hydrogen at a high level. In order to ensure this, scientifically sound measuring methods, evaluation criteria and technical standards are being developed and adopted internationally - regulations that will also have to be taken into account in future in the day-to-day operations of a metallurgical plant designed for the production of "green steel".

 

Politics must also transition

So while industry and academia are offering technical solutions for the decarbonization of the steel industry, the prerequisites for their operation are still missing. "The plant technology is available. What is still missing is the necessary regulatory framework for economic operation," as Dr. Alexander Redenius, SALCOS® project manager, sums up the current dilemma. Among other things, exemption from the EEG surcharge, protection against unfair trade practices and investment subsidies would be expedient.
Prof. Dr.-Ing. Heinz Jörg Fuhrmann, the former Chairman of the Executive Board of Salzgitter AG, refers in this context to the high subsidy efficiency in the steel sector: "The first SALCOS expansion stage avoids as much CO2 emissions in connection with an investment of a good € 1 billion that would be equivalent to replacing one million combustion engine cars with electric cars." As a reminder, the purchase of that many eletrocars would currently be subsidized by up to €9 billion. Prof. Fuhrmann's conclusion is therefore: "With SALCOS, we are presenting the most favorable investment offer in terms of the amount of CO2 that can be avoided in a sector and industry comparison.”
In the meantime, the German government has adopted a national hydrogen strategy and a steel action plan. The concept of the Federal Ministry of Economics for the national hydrogen strategy also explicitly mentions the efforts of the steel industry as a concrete measure for the transition to a hydrogen-based industry. The ruling of the Federal Constitutional Court on the Climate Protection Act, according to which CO2 emissions must now be reduced earlier and to a greater extent than originally envisaged by the legislator, could now bring these efforts into even sharper focus.
As a further step, the first demonstration-scale direct reduction plant will be going into operation on the premises of Salzgitter Flachstahl next year. Along with the implementation of the technology, it will also embody the following realization: The introduction of new production processes in crude steel production were not only a task for the engineers and scientists of the 19th century, they are also on the agenda for their colleagues of the present day.

You will find this and other articles in issue 02/2021 of STIL - the magazine of Salzgitter AG.