Over the years, aboveground storage tank cleaning methodologies have evolved to meet modern requirements for safety, speed, cost-effectiveness and environmental sustainability.
These changes are manifested in how material is removed and processed and how emissions are controlled.
Non-entry cleaning: Tank cleaning was once an exclusively manual process. It was labor-intensive, dangerous and strenuous for workers experiencing extreme temperatures in confined spaces. It was also comparatively slow and expensive.
Today, non-entry methods with advanced automation and robotics have replaced in-tank man-hours whenever possible. In some cases, tanks can remain on line while automated cleaning is in progress. In others, cleaning and degassing are performed simultaneously. The vast array of automated equipment includes remote-controlled manway cannons with cameras and lights that are intrinsically safe, remote-operated vehicles (ROV) that are intrinsically safe for immediately dangerous to life or health atmospheres, tank sweeps with continuous slurry and removal, and more.
Some of the latest robotic combination systems use a common platform for ROV robotics, multiple robotic manway cannons and submersible pumping systems. A single controller can operate multiple devices, providing greater equipment versatility for unexpected scenarios and a smaller physical footprint for on-site equipment.
Material processing: A similar transformation has occurred with the methods used to handle material removed from storage tanks. Material is now processed on-site to recover valuable hydrocarbons, minimize waste and avoid emissions. Options include dewatering/decanting processes with two- phase and three-phase centrifugation, as well as plate-and-frame and belt-filter presses.
Processing technologies are selected based on their ability to minimize waste outhaul and achieve the plant’s objectives. Vapors should be trapped and scrubbed during processing.
Emission control: Emission control has evolved into a vital part of tank cleaning operations, helping tank owners reduce their carbon footprint and comply with air quality regulations enforced by state and federal agencies.
A range of techniques and equipment is available to mitigate hazardous gases and eliminate or reduce the release of volatile organic compounds (VOCs) into the atmosphere.
Mobile scrubber systems safely and efficiently capture and neutralize hazardous air pollutants, VOCs and odor-causing emissions. These systems use chemical, dry media or reactivated carbon.
For vapor destruction, advanced mobile thermal oxidation units can achieve destruction ratio efficiency certifications of 99.98 percent efficiency. These units extract vapors at up to 6,000 standard cubic feet per minute to shorten the duration of vessel clearing.
Integrated service: A final change in the evolution of tank cleaning is the way services are provided. Historically, tank owners had to contract separate providers, adding complexity and cost to the project.
A qualified single-source provider offers uniform safety standards, cost-effective procurement, efficiency and a single point of responsibility and communication for all tank-cleaning needs.
For more information, visit www.usadebusk.com or call (844) 243-5557.
