Use of heat exchangers for waste heat recovery on automotive painting lines

Use of heat exchangers for waste heat recovery on automotive painting lines

The paint shop is a major energy consumer in the manufacturing process of a complete car, where the drying equipment used to dry the paint film is one of the main energy consuming equipment, accounting for thirty percent or more of the energy consumption of the entire paint shop.

In actual production, the heat loss from the exhaust gas treatment system of the drying equipment's heating system accounts for about twenty-five percent of the total energy consumption, the emission temperature of these flue gases drops to 180-250 degrees Celsius, but this part of the discharged flue gases can still be recovered and reused through flue gas waste heat recovery equipment.

Waste heat recovery and utilisation of low temperature flue gas emissions, mainly the use of high temperature flue gas to preheat the fresh air required for drying ovens, heating kiln fan sets, heating pre-treatment line tank liquid and workshop heating, etc.

Case show:

Electrophoresis, medium coating and top coating three gas type straight-through drying ovens, whose exhaust gases are treated by high temperature incineration and preheat the fresh air needed for the drying oven after the chimney exhaust smoke temperature is around 200 degrees, using the flue gas heat exchanger, recovering heat to the drying room

Electrophoresis, medium coating, top coating three gas type straight-through drying furnace, its exhaust gas using centralized treatment, after treatment through the chimney exhaust smoke temperature at about 180 ℃.

Comprehensive analysis of the coating line process shows that the pre-treatment needs to use a lot of heat energy in heating the tank liquid, while the paint drying furnace discharges a lot of heat energy through the exhaust gas, so the more popular energy-saving method at this stage is to recover the waste heat from the flue gas and use it to heat the pre-treatment tank liquid. This mode is the most effective way to save energy and can greatly reduce the energy cost of the whole painting workshop through energy saving renovation.