Stability of refined products and crude oil stored in large cavities in salt deposits: biogeochemical aspects

Abstract

Large cavities in salt deposits have been used in a number of countries for stocking petroleum in strategic reserves and for operational storage. Stocks have included hydrocarbon gases, motor gasoline, home heating oil, jet fuel, and crude oil. Crude oil is not subject to deleterious changes in quality, although it does tend to deposit sludge during storage. No changes in quality of light hydrocarbons such as propane and butane have been reported. During storage in solution-mined cavities, gasoline and middle distillates can become contaminated with brine causing them to fail certain specification tests. Oxygen brought in with the water used to leach cavities can promote autoxidation resulting in formation of soluble or insoluble gum in some products. The walls of salt cavities are largely inert with respect to stored petroleum, and no reactions between them have been reported. Biodeterioration of petroleum is generally inhibited by the high salinity of the brine, but episodic bacterial activity could occur following injections of relatively fresh surface water resulting in catabolism of hydrocarbons, or production of hydrogen sulfide or methane. With careful planning and exercise of a few precautions, most quality problems encountered to date can be avoided. Petroleum stored in cavities in salt should not need to be rolled over as frequently to maintain its quality as it would if stored in aboveground tanks.

Extraction of Hydrocarbons from Crude Oil Tank Bottom Sludges using Supercritical Ethane

“…The feeding section was constituted by a commercial ethane gas cylinder [1], two storage cells [2 and 3] and a LabAlliance positive displacement pump [4], model SFC-24 (State College, PA). The storage cells (constructed in 316 stainless steel, with an individual volume of 220 cm 3 ) were used for storing ethane previous to load it into the extraction section.…”

“…It appears that the formation of sludge during the bulk storage of crude oil is an unavoidable phenomenon resulting from the settling out of suspended and agglomerated constituents of crude oil (1). Unfortunately, COTBS generation causes several problems in most of the refineries worldwide.…”

Recovery and Characterization of Oil from Waste Crude Oil Tank Bottom Sludge from Azzawiya Oil Refinery in Libya

“…During the cleaning processes, all the waste (COTBS) is removed and dumped in designated ponds. The continuous generation of COTBS during the bulk storage of crude oil is an unavoidable phenomenon [3]. COTBS usually contains a significant amount (30-50%) of oil (heavy hydrocarbons) [4], in addition to water (30-50%) and solids (10-12% (w/v) [5].…”