Thermal mass flow meters are ideal to measure flashing and working losses of oil and gas atmospheric storage tank emissions.

Atmospheric Storage Tank

Atmospheric storage tanks are large aboveground containers commonly used oil and gas production, containing liquids of oil or gas condensate. Storage tank emissions from venting are primarily volatile organic compounds (VOC)  which are considered hazardous air pollutants (HAP). Regulatory agencies may require that the emissions be quantified and reported. Additionally, reporting tank venting for greenhouse gas emissions is required under 40 CFR part 98.

Emissions are generated from flashing, working losses and breathing losses. Direct measurement of the vented vapors using thermal mass flow meters provides an accurate method to quantify emissions.

Flashing Losses

When a gas or liquid stream experiences a pressure drop or a temperature increase, flash gas is created. Flash emissions from tanks can occur at the compressor stations, gas plants, pigged pipelines, tank batteries or at the wellhead.

Working Losses

Working losses are emissions which result from the change in liquid level within the tank. As the tank is filled, the vapors within the tank are displaced and flow out the vent. Typical locations include the wellhead, storage tanks, and liquid loading and unloading facilities.

Breathing Losses

Breathing losses occur when vapors are discharged from a tank due to changes in pressure and/or temperature.  They also include vapors from evaporation of the liquid in the tank.

VOC Emission Measurement

Thermal mass flow meters provide the direct mass measurement of emission flow without the need for additional temperature or pressure instruments. Because of the Sage Meters’ low-end sensitivity and wide turndown, the Sage Prime can accurately measure extremely low velocity, down to 5 SFPM, at low pressures, making it extremely effective for measuring the low flow rates associated with venting emissions. These direct mass flow meters are highly accurate and repeatable and have a negligible pressure drop.