Vehicle paint shop without the use of fossil fuels

A state-of-the-art vehicle paint shop that works completely without the use of fossil fuels will soon be put into operation. It reduces the CO2 footprint and uses new processes and systems such as power-to-heat, heat grid and eRTO.

The BMW Group Plant Debrecen is taking shape. The first technology to go into operation at the new production site in Hungary is the ultra-modern paint shop. Thanks to the use of various new processes and systems such as power-to-heat, heat grid and eRTO, the Debrecen plant is the first paint shop in the BMW Group's global production network to operate completely without the use of fossil fuels. The new Debrecen site, where pre-series production of the New Class will start at the end of the year, is thus a blueprint for all future plants based on the principles of the BMW iFactory.

The new paint shop in Debrecen is designed to paint 30 vehicle bodies per hour in a fully automated painting process. This capacity can be significantly expanded at a later date. The plant is equipped with BMW iX1 bodies. The state-of-the-art facility was developed and planned with the help of existing expertise in the production network. The paint shop building has a floor area of 33,000 square meters and three floors of work space for modern production.

The key prerequisite for operating the paint shop in Debrecen without fossil fuels such as natural gas is the power-to-heat principle. All the ovens required for the painting process and other processes are operated completely electrically - instead of using natural gas as was previously the case. This principle significantly reduces the paint shop's_{CO2 footprint}, even if electricity consumption increases as a result of not using natural gas. In Debrecen, BMW obtains its external electricity requirements for production exclusively from renewable energy sources.

The "Heat Grid" energy efficiency project was successfully implemented in the planning of the new paint shop. The innovative concept combines several measures for efficient energy recovery and achieves additional energy savings of up to ten percent. At the heart of the project is a large multivalent storage boiler that bundles the waste heat from the compressed air supply, the drying ovens and the refrigeration systems. This waste heat is then used to preheat the water circuit.

The second special feature in Debrecen is that the system operates with a total water inlet temperature of just 65 degrees Celsius, compared to 90 to 120 degrees Celsius in previous systems. The hot water is used to supply the hall ventilation systems in the paint shop and keep the paint booths at a stable process temperature of 22 degrees Celsius and a humidity of 60 to 65 percent.

The innovative eRTO process is used for exhaust air purification in Debrecen. eRTO stands for electrically regenerative thermal oxidation, a process that purifies the exhaust air from the paint shop at temperatures of 800 to 1,000 degrees Celsius and - unlike in the past - requires only electricity. During the cleaning process, the exhaust air flows through a ceramic bed in which the residual solvents burn off. To do this, the air has to be heated to a high temperature in a short time. Thanks to its high degree of thermal recovery, in which the heat is retained in the system, the eRTO system offers very high energy efficiency.

In the new paint shop in Debrecen, as at many other BMW Group locations, a modern, environmentally friendly dry separation system is also used. The paint overspray, which does not adhere to the bodywork in the paint booth, is filtered out and bound with limestone powder. This significantly reduces water consumption and the paint booth can be operated with up to 90 percent recirculated air. As a result, only ten percent of the air needs to be tempered and humidified instead of 100 percent, which leads to high energy savings. In addition, the stone powder used can be returned to the material cycle and reused in the cement industry, for example, instead of having to be disposed of as contaminated waste water as was the case with the previous wet washing process.

In addition to innovative technologies such as Heat Grid and eRTO, comprehensive digitalization also contributes to the high efficiency of the new paint shop in Debrecen. For example, so-called AGVs (Automated Guided Vehicles) transport the bodyshells to the various work steps in a driverless and fully automated process. In addition, an automated surface inspection system (AOI) is used, which uses artificial intelligence to detect irregularities after painting and record the features that require reworking. The paint shop was planned virtually. This allowed the structural planning to be checked virtually before the actual construction. Introductory training for employees was also carried out virtually in advance. (OM-9/24)