Overspray separation with EcoDryScrubber by Dürr

Audi uses energy-saving Dürr technology to paint in Mexico

Bietigheim-Bissingen, April 1st, 2014 – Plant manufacturer Dürr is supporting its customer Audi in the construction of a resource-saving production in Mexico. Dürr as the general contractor will build one of the world’s most environmentally friendly paint shops at the site in San José Chiapa. This Eco+Paintshop is ahead of the competition, due to a low use of water, energy and materials.

Dürr is responsible for the complete Eco+Paintshop which ensures all interfaces and processes are efficient - from pretreatment via electro-coating (EC) and the booths with their application technology, through to the ovens. Attention is paid to sustainability starting in the PT/ED phase. The Ecopaint RoDip rotational dip painting system is used during pretreatment and EC. RoDip eliminates entry and exit inclines as the car body gets completely rotated in baths. Less water, chemicals and power needs to be used for bath conditioning because of the smaller volumes of these shortened dip baths. RoDip lowers unit costs and offers the best possible corrosion protection via an optimised process of immersion, flooding and draining. 

Underbody and seam sealing is undertaken by ten robots of the type EcoRS16. Armed with the EcoBell3 high speed rotary atomizers, 36 EcoRP L133 robots are responsible for the fully-automated interior and exterior painting in the primer and top coat line. Color changing in the base coat is possible within ten seconds in the push-out process with these atomizers in combination with the color changer EcoLCC2. During the push-out process, the paint valve is closed before painting and the paint material in the color hose is pushed towards the atomizer with solvent. Paint loss during the changing of coat colors is between 10 and 15 ml. During the paint supply, Audi uses proven circulation technology for standard colors, while special colors can be applied with the flexible piggable special paint system EcoSupply P. The color is pushed through the pigging piping without resistance by using pigging (pipeline inspection gauge = fitting body). This procedure is particularly material-efficient and saves money. 24 handling robots to hold the doors and hoods open during interior painting will be used, next to the painting robots.  

The overspray is separated via the energy-efficient paint booth system EcoDryScrubber. This dry separation of the overspray forgoes completely on water and chemicals and the paint booth can be powered by up to 90% recirculated air. The EcoDryScrubber saves up to 60% of energy in the paint booth, as less air conditioning is needed.

The straight-through ovens are conceived for complex car body structures with considerable aluminium add-ons and designed to have low exhaust gas temperatures. The exhaust air streams of all ovens is purified by the integrated oxidation Ecopure TAR with heat recovery and used again for thermal heating. The highly efficient Ecopure exhaust air purification system cleans the remaining minimum exhaust air from the spray booths which has already been reduced by the EcoDryScrubber and its recirculation. The dry separation is responsible for a highly concentrated and very efficiently filtered exhaust air. This enables the use of a very compact exhaust air purification system which drops investment costs for the exhaust system by 60%. In this combination, the power consumption for the exhaust air purification is reduced up to 80% and the solvent emissions drop by 90%.

Audi commissioned this Eco+Paintshop in December 2013 at Dürr. The Q5 models will roll off the production line in San José Chiapa starting midyear 2016.