Crude Oil Storage
Storage of crude oil and other hydrocarbons such as condensate and refined products is needed to provide inventory to keep the plants running if transportation is interrupted. Additional capacity can be provided to allow traders to take advantage of price fluctuations in the market. Adequately sized tanks are constructed as an integrated part of refineries, upstream facilities or standalone facilities for trading.
Tank farms mainly consist of tanks which may be floating roof or fixed roof depending upon product to be stored. Retainment walls or berms or dikes are provided as required for spill containment. Dike walls are provided either for individual tanks or a group of tanks to hold liquid spillage in case of tank rupture.
Instrumentation for level and temperature are provided, along with gauging wells. For fixed roof tanks, depressurization / depressurization systems are provided, along with pressure/vacuum protection. Vent recovery systems may be required. Facilities for bottoms water draw may be provided. Some tanks have sloped bottoms to collect solids and a standpipe for product draw. Finally, fire fighting facilities are provided, often using foam systems.
Depending upon API gravity of crude, heating may be necessary for crude and heavy oil storage. This can be done either by heating medium flowing through a heating coil in the tank or by using an external specially designed plate heat exchanger.
Pumps are provided along with metering system for loading as well as unloading of tanks. In the case of an operating plant, normally, one tank is used for production while another tank is used for loading. In cases where the product is going into a common pipeline, custody transfer meters are provided.
Depending upon preferred mode of loading and unloading, loading station equipped with loading arms are provided for truck, rail car, or ship loading.