VOCs Exhaust Treatment
Coating Line VOCs Treatment with RTO and Scrubber
Three chamber RTO with upstream spray scrubber for a metal coating line, recovering heat back to the curing oven to cut fuel consumption.
Original condition
The problem on site
Two spray booths and one curing oven discharged organic exhaust separately. Paint mist carried into the ductwork, the site permit required a single controlled outlet, and the oven burned natural gas continuously.
Engineering approach
What we designed and built
- 01Combined the three sources into one duct network with dampers so booth and oven flows can be balanced independently.
- 02Added a PP spray scrubber with demister upstream to remove paint mist and particles before the oxidizer.
- 03Selected a three chamber RTO at 45,000 m³/h to keep outlet stability during valve switching.
- 04Returned part of the RTO hot air to the curing oven through an insulated duct with temperature control.
- 05Installed LEL monitoring with automatic dilution air and bypass damper for safe operation.
Measured results
Before and after commissioning
Values recorded on this project under its own operating condition. Results at another plant depend on fuel, material, load profile and the local standard in force.
| Item | Before | After |
|---|---|---|
| Treated air volume | Two booths vented directly | 45,000 m³/h combined to one RTO |
| Non-methane VOCs at outlet | Above site permit limit | Within permit limit per site monitoring |
| Natural gas consumption | Baseline oven burner load | Reduced by heat recovery to the curing oven |
| Paint mist carryover | Fouling of downstream equipment | Removed by upstream scrubber and demister |
Outcome
How the system runs now
The plant now discharges through one monitored stack. Outlet non-methane VOCs measured by the site monitoring system stay within the permit limit under normal production, and part of the oven fuel demand is covered by recovered heat. Actual values depend on production mix and local regulation.
Site records
Fabrication, erection and commissioning
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