Decarbonisation
High electric power share in glass melting Max Kallert* describes concepts for substituting fossil fuels for electric power, which could aid in achieving climate neutrality within the glass industry.
� A classic end-fired furnace including regenerator, distributor and forehearths furnace.
restrictions (e.g. for cullet, pull changes, etc.) applying for a full electric melter. Furthermore, the standard for electric furnaces right now (<200 tonnes per day) is still on the lower end needed in the container glass segment. This is why Horn is developing several hybrid concepts as an alternative. These concepts combine an increased electric power share and the well-known principle of horizontal melting. The word hybrid is an often-used buzzword in this context, but there are varying definitions. Does hybrid mean: � The simple existence of both kinds of power in the furnace? � Equal contribution from electric and fossil sources? � High flexibility ranging from predominantly fossil to predominantly electric contribution? Horn defines a furnace as hybrid if both forms of power, electric and fossil, are needed for sufficient operation. Therefore, an end-fired furnace with
electrical boosting up to 10-15% would not be considered a hybrid furnace, whereas a 50/50 contribution from both fossil and electric sources would clearly be a hybrid furnace.
Considerations For hybrid furnaces, some current working standards (for fossil furnaces) have to be reconsidered. The incorporation of a higher amount of electric power makes it necessary to increase the number of electrodes in the melting basin too. Each bottom electrode creates locally a strong vertical flow that interferes with the main horizontal convection, known from the horizontal melting process. If a high number of electrodes are positioned evenly and extensively over the basin bottom, a broad disruption of the typical convection flow is a probable consequence. That is why Horn prefers a certain positioning of Continued>>
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n times of global warming, the push to reduce carbon dioxide emissions and reach climate neutrality is also influencing the glass industry. Right now, fossil fuels are still covering the majority of the energy consumption in the production of glass. Current measures to cut down fuel consumption include heat recovery for batch, cullet and gas preheating as well as direct substitutions with more sustainable fuels (like hydrogen or bio gas). However, the incorporation of green electric power into the glass production could be the way to go. Compared with green fuels, electricity in the melting process has the advantage of higher availability and lower prices (due to better efficiency). A logical, but radical, step now would be to completely switch to electric energy and use a full electrical vertical melter. This would mean huge changes in operating compared to the current fossil furnaces and their horizontal melting principle. This is due to different
19 Glass International February 2022
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