DLR tests cement production with solar energy
Large amounts of carbon dioxide are released during cement production. The DLR is working on a clean method.
Solar calcination plant in front of the DLR's Synlight solar simulator
(Image: DLR (CC BY-NC-ND 3.0))
The building materials industry is one of the major global emitters of carbon dioxide. Researchers are therefore looking for ways to decarbonize cement production. A team at the German Aerospace Center (DLR) plans to use sunlight to produce cement in the future.
The most energy-intensive process in cement production is so-called calcination, where limestone is heated to temperatures of over 900 degrees in a rotary kiln. According to the DLR Institute for Future Fuels, fossil fuels are mainly used for this purpose today. Calcination accounts for about 60 percent of the carbon dioxide emissions from cement production.
As part of the CemSol project, DLR researchers are using a rotary kiln heated by concentrated sunlight. They tested this using the world's largest facility for generating artificial sunlight: Synlight was used to heat the kiln to the required temperatures. In a multi-month test campaign, according to DLR, 25 irradiation tests were carried out at power levels of up to 65 kilowatts. Between 15 and 50 kilograms of limestone particles per hour were fed into the solar calciner and calcined 100 percent. In this way, more than 90 percent of the carbon dioxide emissions from calcination could be avoided.
Testing the produced limestone
Next, the researchers want to examine the calcined limestone produced in the kiln, a total of more than 90 samples. This involves the material quality and the long-term stability of the process.
In addition, they wish to analyze the processes in the reactor regarding heat transfer and the reaction of the limestone particles using computer simulations. The data obtained will be used for the further development and scaling of the technology.
The use of solar energy reduces dependence on expensive and harmful fossil fuels, summarizes project manager Gkiokchan Moumin. "The key to more climate-friendly use of our resources lies in a mix of different energy sources. Concentrated solar energy can be used efficiently for high-temperature applications and bring us one step closer to this goal in conjunction with electricity from renewable sources."
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This technology could be "a highly attractive alternative to electrical heating of the material," and its use is particularly suitable in the southern regions of the European Union (EU). In MostĂłles, near the Spanish capital Madrid, the DLR has been testing the production of synthetic fuel using solar energy in a solar tower power plant for several years. The use of a solar-heated rotary kiln would also be conceivable in such a plant.
(wpl)
