VRU Oxygen Analyzers for Vapor Recovery Units
OxyScout is the optical oxygen analyzer built for vapor recovery units — continuous, in-line O₂ monitoring that protects your pipeline spec, your compressor, and your uptime, with no consumable cells to replace.
A vapor recovery unit (VRU) captures hydrocarbon vapor from storage tanks and other low-pressure sources and compresses it back into the sales line instead of venting or flaring it. The problem is oxygen. The moment air sneaks into that low-pressure vapor stream, the recovered gas can go off-spec, corrode downstream steel, and create a combustible mixture inside your own equipment. OxyScout is an optical based oxygen analyzer that measures O₂ in the recovered vapor stream in real time, so operators catch ingress the instant it starts — not weeks later when a custody-transfer sample fails. Built for upstream oil and gas, from single well-pads in the Permian Basin to multi-tank gathering stations, OxyScout delivers the accuracy of optical sensing without the recurring cost of electrochemical cells.
Why Oxygen Monitoring Matters in a Vapor Recovery Unit
Even trace oxygen is a problem in recovered gas, and the consequences stack up fast.
Pipeline rejection. Sales-gas pipelines enforce strict oxygen limits in their tariffs. In North America those limits commonly fall between roughly 10 and 50 ppm, with some tighter systems holding as low as 5 ppm and others tolerating up to about 1%. Gas that exceeds the spec gets rejected — and a single off-spec event at custody transfer can mean lost revenue, deferred production, and a hard conversation with the gatherer.
Corrosion. Oxygen is uniquely aggressive inside steel pipe. It accelerates nearly every corrosion mechanism, and when it's present alongside CO₂ or H₂S it makes them dramatically worse, attacking pipelines, vessels, and compressors from the inside.
Safety. Oxygen mixing into a hydrocarbon vapor space can form a combustible mixture inside the VRU and connected tankage. Continuous O₂ measurement is a frontline layer of process safety, not just a quality check.
Equipment and compliance. Air ingress can foul downstream treating equipment and undermine the emissions performance the VRU was installed to deliver in the first place. Knowing your O₂ number, continuously, keeps the whole system honest.
How Does Oxygen Get Into Recovered Vapor?
VRUs run at very low suction pressure — tank vapor is typically pulled at just 0.25 to 2 psig — which makes the system easy to tip into a slight vacuum. When that happens, ambient air is drawn straight into the vapor space. The most common entry points are:
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Leaking or open thief hatches on storage tanks
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A vacuum pulled by the VRU when it can't slow down fast enough to match falling vapor generation
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Day-to-night temperature swings that contract the tank vapor space
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Worn tank seals, loose fittings, and leaking pressure/vacuum relief valves
These conditions are intermittent and easy to miss with periodic grab samples. That's exactly why a continuous oxygen analyzer at the VRU matters: ingress events are often short-lived, and you can only act on what you can see in real time.
How OxyScout Monitors O₂ in Your VRU
OxyScout taps the recovered vapor stream and reports oxygen continuously. Instead of a galvanic cell that gets consumed by the oxygen it measures, OxyScout uses pure optical sensing: a light source excites a sensing element and produces a signal that gives a precise O₂ reading. Nothing is consumed in the measurement, so the sensor doesn't deplete, doesn't get poisoned by H₂S, and doesn't drift the way electrochemical cells do. When O₂ climbs toward your spec limit, OxyScout drives an alarm so operators can tighten seals, adjust the VRU, or divert vapor to a recovery tower before off-spec gas ever reaches the pipeline.
Benefits of OxyScout for Vapor Recovery Units
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Catch air ingress in real time. Continuous, in-line O₂ measurement flags ingress the moment it starts, instead of weeks later at the lab.
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Protect your pipeline spec. Stay ahead of tariff O₂ limits and avoid costly custody-transfer rejections and curtailments.
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No consumable oxygen cells. Optical sensing isn't consumed by the measurement — eliminating the electrochemical cell replacements that drive legacy analyzer maintenance every few months.
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Immune to H₂S poisoning. Sour, wet VRU gas degrades galvanic cells quickly; OxyScout's optical sensor is unaffected.
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Low drift, stable readings. Hold accuracy between service intervals, so the number you see is the number that matters.
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Lower total cost of ownership. Fewer consumables and less downtime add up to a clear 3–5 year TCO advantage over electrochemical analyzers.
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Faster response. Quick reaction time means ingress events get caught and corrected before gas goes off-spec.
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Built for the field. Designed for upstream wellsite and gathering-station conditions across the Permian Basin and beyond.
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Adds a layer of safety. Continuous O₂ visibility helps keep the vapor space out of the combustible range.
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Scales across your fleet. One proven platform from a single VRU to hundreds of pads, with fleet pricing for large deployments.