(Mainz) – Schott AG, together with Mainzer Stadtwerke AG, has launched a pilot project to test the large-scale use of hydrogen in glass production. According to a press release, the largest share of Schott's high energy consumption and CO2 emissions arises from the melting process.
In order to produce special glasses for vaccine vials, cell phone protective glass or microchips, temperatures of up to 1.700 degrees Celsius are required. So far, the melting tanks have been heated primarily with natural gas and sometimes also with electricity. The group will now test the addition of hydrogen for the first time in large-scale melting tests in a tank at the Mainz site.
Replacing natural gas with hydrogen
Over a period of one month, the hydrogen content in the natural gas-hydrogen mixture will be gradually increased to up to 10 percent by volume in three test phases lasting approximately 35 days. The aim is “to use the experiments to learn more about the effects of the use of hydrogen on glass melting processes in order to largely avoid CO2 emissions in the long term.” According to the information, the project costs amount to more than 714.000 euros. The Rhineland-Palatinate Ministry of the Environment is funding the project with 338.000 euros.
To advance climate-friendly glass melting processes, Schott AG – whose sole shareholder is the Carl Zeiss Foundation – has already launched several research projects focusing on electrification with renewable electricity and hydrogen. For example, a year ago the glass manufacturer tested melting three different types of glass using hydrogen. The result was positive: When firing with hydrogen and oxygen, a similar burner output and temperatures were achieved as with the conventional process using natural gas and oxygen. The quality of the glass produced was also similar to that of conventional glass, Schott explained at the time.
It was not clear from the start that this would work. Natural gas cannot simply be exchanged for hydrogen, according to the report from the Copernicus project “P2X”, funded by the Federal Ministry of Education and Research, as part of which the tests took place. Both gases burn with different reactions. In order for hydrogen to actually be used to melt glass, it must be used “in such a way that it emits the same heat radiation as natural gas.”
Experiments with hydrogen also in Italy
Last July, several Italian companies also announced plans to test the use of hydrogen to power melting furnaces in glassworks. A working group led by the long-distance gas pipeline operator SNAM, RINA, and the glass manufacturer Bormioli Luigi has set itself the goal of reducing emissions in the glass industry. No results have yet been published.
Italy is the second largest glass producer in Europe, with over five million tons per year. According to SNAM, the current CO2 emissions from natural gas from Italian glassworks amount to around 1,5 million tonnes per year; about 3,5 percent of the emissions from the country's entire manufacturing industry. The widespread use of a hydrogen admixture of 30 percent in the glass melting process would reduce emissions by 200.000 tons.
Photos
Special glass is melted at temperatures of up to 1.700 degrees Celsius © Schott AG
