This content is relevant for:Energy Efficiency
Many production processes in energy-intensive industry require temperatures of more than 1,500 degrees Celsius - for example in steel and ceramic production. Insulation helps ensure as little of this heat escapes from the furnaces as possible. Because the better the insulation, the less energy is required to heat up and maintain the temperatures needed.
Germany’s AeroFurnace research project is developing a new composite material based on nanoporous carbon that could have more than double the thermal insulation effect of existing materials. Such a material could significantly reduce the energy requirements of high-temperature furnaces. The new insulation is also not thicker than current felt-based carbon materials, meaning there is no reduction in the usable volume of the furnace.
Dr. Gudrun Reichenauer coordinates the research project and heads the nanomaterials working group at ZAE Bavaria. She is very satisfied with the results so far: “In this project, through intensive cooperation, we have succeeded in bringing the latest findings from the world of nanomaterials to the market and are thus setting new standards in the field of thermal insulation materials,” she says.
The thermal insulation in blast furnaces must be able to withstand the extreme heat without any problems. The only materials that have achieved this to date have a rather high thermal conductivity, meaning they also like to give off heat. That is bad for energy efficiency. The team of scientists are therefore looking at a certain group of substances: carbon aerogels, whose thermal conductivity is particularly low. Aerogels can be made from various materials such as silicates, metals and their oxides, polymers, biopolymers and carbonates. They are so porous that they are more than 90 percent air or free space. That makes them particularly light. They have a low density, a large internal surface and a low thermal conductivity.
Dr. Thomas Kirschbaum, AeroFurnace project manager at carbon producer SGL Carbon, sees a bright future for the new thermal insulation material:
“In furnace simulations at our partner FCT we have already been able to demonstrate what the new material can do. Depending on the temperature program, process energy savings of up to 40 percent can be achieved with the new thermal insulation. It has great potential.”
The carbon aerogels used in the AeroFurnace project have another advantage. Their fine carbon structure absorbs the majority of thermal radiation, which is responsible for most of the transport of heat at high temperatures. They can be used as super-insulators in particularly demanding areas, for example in the automotive industry, in insulation systems for buildings or high-temperature applications.
The scientists in the AeroFurnace research project have already shown that the new material can be made using technically simple processes in the lab and that it is easily scalable. However, there is still a long way to go before the product is ready for mass production.
The material needs to be proven in industrial settings before it can enter the market and studies under real-life conditions are only possible if larger scale manufacturing processes can be achieved. The project’s funding enables both tasks to be tackled in parallel.
In the second half of the research project, the team wants to test the new insulation in a high-temperature furnace and compare it with an identical furnace equipped with conventional insulation material.
Several research projects funded by the Federal Ministry for Economic Affairs and Energy (BMWi), including the AeroFurnace project, have joined forces in the Aerogel Cluster to promote the widespread use of aerogels in industry.
The research cluster aims to develop a long-term strategy for the successful establishment of aerogels. The scientists have shown that the potential is great. Aerogels combine numerous properties that no other class of material can offer in combination: good sound absorption, low thermal conductivity, low density and a large internal surface area, making them extremely light and pressure-resistant. The chances are therefore good that high-quality aerogels and will be available for a wide range of applications soon.
The Federal Ministry for Economic Affairs and Energy (BMWi) is funding the AeroFurnace project over a period of three and a half years with around 625,000 euro.