mt basic operation
The MT unit recovers evaporative vapors and Stage I vapors created during product delivery to the service station’s underground storage tanks.
As the delivery truck drops the load, vapor is generated and pushed out of the storage tank and into the MT unit via the vapor return line for separation and collection.
A single carbon bed designed to take the maximum vapor load generated during truck unloading accepts the generated vapors. As the vapors travel into and out of the carbon bed, clean air discharges into the atmosphere.
Once the truck unloading operation is complete, the MT unit is set for the regeneration mode. The vacuum pump de-absorbs the captured (rich) hydrocarbon vapors and discharges the saturated volatile organic compounds (VOCs) directly into the underground gasoline storage tank.
Once the saturated vapors are discharged into the liquid gasoline they may be readily absorbed into the gasoline.
Vacuum regeneration of the MT unit requires a fixed amount of time during which no other delivery can be made to the facility. During MT unit regeneration, gasoline loading at the dispensing area may continue uninterrupted.
m2 basic operation
The components of the completely automatic M2 VRU include two carbon beds, a regeneration vacuum pump, a group of eight switching valves, a temperature switch and optional water cooled heat exchanger.
Excess vapors generated from the dispensing area or underground tanks are sent via the vapor pipe to the inlet of the M2 carbon pressure swing unit. The carbon beds operate on a 15-minute pressure swing cycle. While one bed is on line accepting and processing vapors, the other is off line being cleaned (vacuum regenerated) by the pump.
Vapors travel into and out of the online carbon taking a maximum load of vapors generated in a 15 minute period. The carbon bed is collecting the volatile organic vapors on the carbon and venting clean air out of the vent.
The vacuum pump of the regenerating (offline) bed de-adsorbs the captured (rich) hydrocarbon vapors and discharges the saturated volatile organic compounds directly into the liquid gasoline in the underground gasoline storage tank. Site specifics, like storage tank size, ambient heat, and the vapor pressures of stored petroleum liquid dictate the need for the optional water cooled heat exchanger.
Once the saturated vapors are discharged into the liquid gasoline they may be readily absorbed into the gasoline. Depending on temperature and vapor pressure characteristics of the stored gasoline, absorption may not be 100% efficient. Remaining vapors will discharge from the storage tank and mix once again with vapors from the dispensing area and cycle through the process outlined above.
Our process allows the service station tanks to remain under a slight negative pressure at all times. This prevents fugitive emissions from the tanks that no other systems can offer today.
