The BMW Group has developed a way to electrically power exhaust purification in its paint shops.

The new process, electric regenerative thermal oxidation (eRTO), creates the high temperatures needed for thermal purification of exhaust from paint booths and drying areas rather than relying on natural gas, according to a BMW news release.

eRTO burns off gaseous or vaporous substances at temperatures up to 1,000° Celsius. Before being released into the atmosphere via chimneys, exhaust from paint booths and drying areas is purified to prevent paint shop solvents from harming the environment.

Purification is done by passing the exhaust through a bed of ceramic media where the solvent residues are burned off. To do this, the air has to be heated up to very high temperatures in a short space of time, BMW said. The energy needed to do this could previously only be provided by natural gas but is now provided by eRTO.

The eRTO system is installed between the painting booth, drying process, and chimney. Thermal energy is recovered by a flat, two-meter-deep ceramic bed which serves as a recuperator. Electrical rods heat the surrounding ceramics, and because most of the heat is retained, a connected load of just a few hundred kilowatts is sufficient to run the system, BMW said.

“For other energy-intensive paint shop processes, such as vehicle drying and water heating, solutions already exist for working without natural gas,” said Michele Melchiorre, BMW Group head of production system, planning, tool shop, and plant construction, in the release. “Electric exhaust purification is the final steppingstone for the BMW Group to run its paint shops on regenerative energy in the future.”

The eRTO system was initially function-tested in ongoing paint shop operations at BMW Group Plant Regensburg. It is being further validated at BMW Brilliance Plant Lydia in China where an eRTO system is used to purify exhaust from the drying system for car bonnets.

Plant Dingolfing has converted four paint lines to the new system for series production. More systems are planned for the production network.

When the BMW Group’s newest plant begins full operation next year in Debrecen, it will use only the new method.

Images

Featured image: BMW 5 Series production at BMW Group Plant Dingolfing. (Provided by BMW Group)

Secondary photos also provided by BMW Group