The Problem: As gathering systems have increasingly tightened and enforced their oxygen specifications to 10 PPM or less, vapor recovery units (VRUs) pulling off of oil storage tanks are becoming unusable. Since oxygen invariably contaminates tank vapors, standard VRUs cannot process this gas stream within oxygen specifications. While EcoVapor has long had a line of VRUs integrated with its patented ZerO2 System, a large Permian producer challenged us to develop a stand-alone oxygen removal unit that could be paired with their existing fleet of VRUs. A few months later, the first ZerO2 with 300 MCFD nominal capacity system was being field tested on a site in the Permian Basin.
The Solution: The ZerO2 E300 was connected just downstream from a 3rd party VRU. The ZerO2 is electrically powered, and like all of EcoVapor’s offerings, it incorporates an on-board PLC to monitor, control, and communicate the system’s operation. This particular system was customized to include several optional items, including separate inlet and outlet oxygen measuring systems, and an inlet/outlet gas-to-gas heat exchanger which reduced power consumption after startup by up to 90%.
The Results: The results were quick and clear. The ZerO2 E300 quickly and completely removed free oxygen from the gas stream, down to less than 1 PPM. Given the strong results, the producer stress tested the system by introducing tanker truck vapors which spiked the inlet oxygen as high as 50,000 PPM –all while the ZerO2 continuously delivered gas to the sales pipeline at less than 10 PPM. Coincidentally, shortly after testing the ODS, the operator had an oxygen event from a standard VRU that caused them to shut in all VRUs in their field. They are turning to the ZerO2 System field wide as a solution to enable them to use their existing VRUs to pull flash gas directly from tanks, allowing for 100% emissions capture and lower, safer tank pressures.