Closing the loop on solvent drum filling without killing throughput

We’ve been tightening up VOC control on our solvent drum/tote lines. We moved from open bung filling to closed-loop heads with vapor return to a header tied into a carbon bed. Emissions dropped and the room smells better, but we ran into backpressure swings that slowed fills and created occasional drips at disconnect. We stabilized it with a backpressure regulator on the header, pressure transmitters at the fill skids, and a short pause before decoupling to let the return equalize. Throughput is back up, but not quite to pre-change levels.

Two other lessons: grounding and scale behavior. Ground verification interlocks cut our near-miss static events, but we still see nuisance trips on rusty drums and in humid weather. And net-weight scales in Class I, Div 1 are robust, yet foamy solvents make the PID chase; mass flow with density comp works great on clean streams but hates viscosity swings.

For those in oil, gas, and petrochem packaging: how are you balancing closed vapor control with speed? Any preferred dry-break couplers, grounding systems, or control strategies that kept you under limits without bottlenecking the line?