New Technology for Autonomously Collecting VOC Samples near Oil and Gas Operations Under Specified Meteorological Conditions

Emissions of volatile organic compounds (VOCs) can be an important air quality issue near oil and gas operations. Concentrations of VOCs downwind of a source are often highly variable in time and space depending on how plume dispersion is affected by source strength, meteorology, and obstructions or topography. New field technology was developed that autonomously samples VOCs into evacuated glass bottles (Bottle-Vac, Entech Instruments Inc.) under user-specified meteorological conditions (e.g., wind direction arc, minimum wind speed). The system was composed of multiple stations deployed on the periphery of the operation (e.g., well pad, condenser tanks, etc.) – one station upwind and one or more stations downwind. Each sampling station contained nine Bottle-Vacs that could be filled independently using a low-cost auto-injector. The injection system was made from a modified 3D printer (K8200, Velleman) and controlled by an Arduino microprocessor board. A pump and air handling system routed air to the auto-injector using coated stainless steel and PEEK tubing. Each sampling station was powered with a 12V batteries and small solar panel. Weather conditions were monitored at one of the downwind sampling stations and real-time data were used to coordinate sampling at all other stations using a wireless network. Typically, samples were only collected when wind direction was from the direction of the source and wind speeds were greater than 1.4 m/s (i.e., conditional sampling). Every one or two weeks the filled bottles were retrieved and replaced with clean, evacuated bottles. The filled bottles were returned to the laboratory for VOC analysis (e.g., BTEX). The presentation will include details on system design and preliminary results from field-testing at oil and gas operations in Colorado, USA.