Quick answer: a vapor recovery unit (VRU) stays reliable when maintenance is layered — short daily checks by station staff, monthly inspections of condensate and membrane operating conditions, and a scheduled annual service covering seals, sensors and heat-exchanger cleanliness. A written schedule, not memory, is what keeps Stage III membrane units passing compliance tests year after year.
Daily Checks (Station Staff)
- Confirm the unit powers up and the controller shows normal status, no active alarms.
- Walk the unit: listen for abnormal compressor noise, look for oil or solvent traces under the skid.
- Check the membrane exhaust visually or via the panel indicator — any persistent strong odor at the vent deserves a log entry.
Monthly Tasks (Technician)
- Record suction and discharge pressures of the compressor and compare against the commissioning baseline.
- Check condensate drain paths for blockage; accumulated liquids left standing in the condensing stage shorten equipment life.
- Review membrane inlet temperature and pressure — membranes are sensitive to both, and drift here is the earliest sign of upstream trouble.
- Inspect electrical enclosures, fan operation and alarm functions.
Annual Service (Scheduled Shutdown)
| Item | Action |
|---|---|
| Compressor seals & oil | Replace per running hours; record |
| Heat exchanger | Clean coils, verify temperature split |
| Sensors & valves | Calibrate pressure/temperature transmitters, exercise safety valves |
| Membrane performance | Compare vent concentration against acceptance data |
Common Failure Patterns We See
Most membrane-unit complaints trace back to three root causes: liquid slugs entering the compressor because drains were ignored, membrane exposure over the specified temperature or pressure envelope, and skipped calibration that lets alarms drift out of range. All three are preventable with the layered schedule above — none require exotic spares.
FAQ
What is the typical service life of a vapor recovery membrane?
Within its designed operating envelope and with clean upstream conditions, membranes serve for years; exposure outside the envelope is the usual cause of early replacement.
Can maintenance be scheduled around fueling hours?
Monthly items are short checks that fit between delivery windows; the annual service needs a planned short shutdown and is best booked in low-traffic periods.
Who keeps the maintenance records?
Station operators should keep a bound log per unit; Luoyang Wohong Petrochemical Equipment Co., Ltd. provides record templates with delivered equipment and supports remote review.