What the Unit Does
Wet gas enters the contactor, rises through glycol, and leaves dry to pipeline spec. Rich glycol is regenerated in a reboiler that boils off the absorbed water. The vent from the regenerator carries methane, benzene, and other volatile organics that were absorbed from the gas.
What EPA Expects
EPA's oil and gas NSPS rules under 40 CFR 60 (Subpart OOOO and successors) set emissions controls and monitoring for well-site equipment including dehydrators. The AP-42 compilation documents the emission factors agencies and operators use to estimate what a glycol unit vents. Compliance turns on controlling or routing the vent and keeping records.
Maintenance That Keeps It Legal
A unit that over-circulates glycol burns excess fuel and vents more. Regular checks: circulation rate, reboiler temperature, glycol condition and pH, and filter changes. Dew point checks on the outlet prove the unit is doing the job. Every control device, from flare to vapor recovery, needs its own inspection schedule.
The record that closes the loop
Glycol Dehydration Units rests on the same field data as the rest of the operation: tickets, timesheets, approvals, and inspections. The same discipline shows up in Compressor station maintenance and Flare efficiency measurement and reporting and Pipeline integrity for gathering lines. If those records live in notebooks, email, and memory, start with an operations audit.