Waste heat recovery in the glass industry
20.2.2019
Glass is one of the most sustainable existing packages, it is made by natural elements, it is largely reusable and 100% recyclable. However, the production is high energy demanding, furnaces operate at temperatures of over 1500°C, 24 hours a day and 7 days a week, making glass production a significant source of waste heat. (https://www.mtpv.com/markets/glass/ ). Energy costs make up roughly 25% of the total production costs and 80% of the primary input is wasted, allowing a large room for improvement. (https://www.aigmf.com/Presentation%20on%20Waste%20Heat%20Recovery%20System%20&%20Energy%20Conservation.pdf)
There are several possible solutions to recover heat and increase the energy efficiency of a glass production plant:
- exploit the heat for internal thermal uses (eg preheating raw materials and fuel, generating process steam or for auxiliary systems, heating rooms)
- exploit the heat for external thermal uses (eg other industrial users in medium and low temperature or district heating/cooling)
- generate electricity, usually consumed within the plant itself thanks to technologies such as the Organic Rankine Cycle ORC) http://www.hreii.eu/demo/public/130801_GLASS%20WORLDWIDE%20(impianto%20vetro%20AGC).pdf
There exists already operational heat recovery to electricity installations across Europe.
For example, In Italy, at Villotta di Chions, OI Glass container plant runs a 0.5 MWe ORC generator http://www.o-i.com/uploadedfiles/content/sustainability/o-i-sustainabilityreport_fasingle.pdf and a 1.3MWe ORC generator was installed in 2013 at the AGC Flat Glass plant in Cuneo. https://www.turboden.com/case-histories/1422/agc
In Germany other heat recovery systems based on Siemens technique allow for a 60 % of electricity produced by own waste heat flow https://feve.org/case_study/waste-heat-recovery-technologies-largely-used-in-the-european-container-glass-industry-to-optimize-energy-consumption-and-reduce-co2-emissions/
Photo by Jason Leung on Unsplash
