Crude oil, a product of millions of years of compounding, biological processes, refers to the chemical byproduct of fossilization, which is untreated and unrefined. When oil storage tanks develop accumulated contaminants, which then settle at the bottom, this sediment in create problems and outflow. Formation sands, or naturally occurring solids, rust, piping scales and other hydrocarbons build up in the bottom of a storage tank, it becomes the sludge. Typically, these consist of sediment, water, hydrocarbons, and paraffin. These can accelerate corrosion and inhibit oil storage tank capacity.

What’s that Sludge?

Both inorganic freighted tank bottom sludge and paraffin-based crude oil sludge can form when the conditions are right. Dipole forces called London Dispersion Forces, or Van der Waal bonds, create molecular aggregation. When hydrocarbons flocculate (those that are predominantly heavier C20+ hydrocarbon molecules), they become liberated from suspension within a static fluid, accumulating as a viscous gel on a tank’s floor. Eventually, this gel stratifies, with volatile components flashing from the gel out as changes occur in temperature and pressure. This expulsion of volatile components concentrates heavier fractions within the sludge, which results in increased density, viscosity, and decreased mobility, creating a vicious cycle.

Plant-based, and environmentally-friendly solutions for affective oil storage tank cleaning are now available. Periodic cleaning of oilfield storage tanks may be done to comply with state or federal regulations as well as to ensure optimal production. In California, for example, Assembly Bill 1960, requires oil tank inspections. Maintaining routine oil tank cleaning is also useful for making repairs or to reconfigure or even remove from service. G-Clean allows oil storage tank cleaning crews to work with a biodegradable cleaner that effectively and efficiently traps harmful, volatile organic compounds (VOCs), thereby supporting the safety of oil field personnel as well as the local community.

Common Applications Include:

• Internal and external cleaning
  
• Transport tanker cleaning
  
• Piping and equipment located in tank batteries cleaning
  

Sources:

1. “Major Work Activities for Tank Cleaning Operation” from OSHA: https://www.osha.gov/SLTC/storagetank/work_activities.html.
   
2. “G-Clean Storage Tank Cleaner” from E&B Green Solutions: http://www.ebgreensolutions.com/products/storage-tank-cleaner.