High Efficiency Tertiary Vapor Recovery System for Underground Fuel Tanks｜Vohon Petrochemical
High efficiency tertiary vapor recovery system is engineered to handle volatile hydrocarbon vapor generated from underground fuel storage tanks at filling stations. Tank breathing emission occurs during fuel unloading process, daily fuel dispensing and ambient temperature changes. Without effective treatment, gasoline vapor escapes into the atmosphere, resulting in considerable fuel loss, air pollution and potential flammable risk around tank farm areas. This system applies physical compression‑condensation coupled membrane separation technology to capture and liquefy oil‑gas instead of destructive combustion, balancing emission compliance and resource recycling.
Oil‑gas exhausted from tank breathing valves is guided into the system via closed collection pipelines. An integrated buffer module stabilizes unstable pressure and flow rate brought by intermittent breathing behavior of underground tanks. Pre‑treatment units separate entrained liquid droplets and fine impurities carried in oil‑gas flow, avoiding liquid carry‑over and particle contamination to protect compressors, condensers and membrane modules, reducing failure rate of core components.
The incoming oil‑gas mixture is compressed to elevate hydrocarbon partial pressure before entering multi‑stage condensation units. Under controlled low‑temperature environment, most gasoline vapor condenses into liquid phase. Recovered liquid fuel can flow back into underground storage tanks for reuse. Residual uncondensed gas proceeds to membrane separation assembly. Utilizing selective permeation performance of polymer membrane, hydrocarbon molecules are enriched on the permeate side, while treated clean gas meets local emission standards and is discharged. The concentrated high‑concentration oil‑gas stream loops back to the compression inlet for circular processing, greatly improving overall vapor recovery efficiency.
Designed for petrochemical hazardous locations, the whole system complies with explosion‑proof standards. Multiple safety interlock mechanisms monitor over‑pressure, over‑temperature and abnormal liquid level in real‑time. Emergency vent bypass is reserved to guarantee safe operation under abnormal working conditions. On‑site HMI panel displays pressure, temperature and running status, supporting data communication with filling station control system for centralized monitoring.
The system can be supplied as skid‑mounted package. Factory pre‑assembly and pre‑commissioning reduce field workload significantly. It adapts to brand‑new filling station construction as well as retrofitting of existing underground tank groups. With high recovery rate and low energy consumption, it cuts fuel loss caused by underground tank breathing emission, helps operators satisfy environmental regulatory requirements, and provides reliable long‑term operation for underground fuel storage sites.