Pilot plants: Solar furnaces melt steel waste with energy from the sun
Two Swiss solar ovens are to help recycle stainless steel and make the process as environmentally friendly as possible. Solar energy is sufficient for this.
Panatere's solar furnace is designed to help melt and reprocess stainless steel waste.
(Image: Panatere)
Swiss recycling specialist Panatere inaugurated two solar furnaces on Friday, which will be able to melt steel waste using solar energy alone. The company mainly wants to process “high-quality” waste from local watch manufacturers and biomedical companies. A lot of stainless steel is used in both industries.
The pilot project for the two solar furnaces was implemented with the help of the Haute Ecole Arc Ingénierie and the University of Franche-Comté in La Chaaux-de-Fonds, Switzerland, as part of the Interreg France-Suisse1 program. The plant has already been built to its original size. There are already life-size installations of solar-powered ovens around the world. However, the Swiss plant is said to be the only one capable of melting steel waste and recycling it into a new, high-quality alloy.
High temperatures thanks to focused solar radiation
This is made possible by a heliostat made of flat mirrors that can follow the path of the sun to capture the sun's rays in the most energy-optimized way possible. The rays are passed on to a concentrator made of concave mirrors, which focuses the light and passes it on to a solar reactor.
The reactor contains a furnace with a crucible in which the steel is melted. Temperatures of up to 2000 °C can be generated. This is sufficient to melt stainless steel. Its melting point is between 1400 and 1550 °C, depending on the alloy. However, these values are still theoretical. The figures were determined using numerical simulations but have yet to be proven in practice.
The two pilot plants are of different sizes. The larger system has a heliostat with an area of 138 m² and a concentrator with 40 movable mirrors on an area of 65 m². The smaller system is more compact with its 30 m² heliostat. However, the concentrator is equipped with 460 mirrors spread over just 12 m². According to Panatere, this should result in a higher energy concentration and efficiency.
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Fossil fuels are not used in the process. The steel can therefore reduce the ecological footprint of the companies that use the stainless steel for their products. This is because the production of stainless steel 1.4441 generates around 6.8 kg of COâ‚‚ per kilogram of steel, explains LoĂŻc Bonsack from Panatere. With the solar ovens, emissions can be reduced to just 41 g, thus significantly reducing the environmental impact.
On an industrial scale, such solar ovens could be used locally by several companies, according to the plan for the future. This would result in a local source of supply, giving the companies more autonomy. However, the systems will first be tested and used for research purposes.
(olb)
