What is oil washing?

Oil washing is a method of cleaning the storage tanks of oil tankers using raw oil as a solvent. When the oil is sent over long distances, the sediment layers separated from the oil and are stored on the walls of the storage tank. In the past, it was removed using high -pressure seawater hoses, while the resulting contaminated water was generally pumped into the sea. Cleaning the walls of the high -pressure oil spray with sediments dissolve back into liquid oil and can be pumped to the nasal storage containers along with the rest of the cargo. This method has the advantage of reducing pollution and waste by cargo and using oil washing in large oil tankers has been required by law since the late 70 years. Some of them, including waxes, tar and sediments, tend to separate from liquid oil and build on the inner walls of the storage tanks. This accumulation of solid material, known as Clingage, can significantly reduce the capacity of storage tanks over time and can cause clogging or PIRUCHU pumping mechanisms. As a result, it is generally removed from the storage tanks at the end of the voyage.

Until the end of the sixties, the attachment was removed by browsing the inner walls of the storage tanks using the same high -pressure seawater pumps used to clean the deck of the boat. In this way, it took a lot of water because the oil is not soluble in water. The resulting mixture, which could contain up to 800 tons of oil to 20,000 tons of tanker, was used as a load and then pumped into the ocean at a certain distance at the sea. Alternatives were sought due to growing pollution concerns caused by this method.

The oil washing method has entered the extension of the use at the beginning of the 70s. Pumping mechanisms have been designed to produce a high -pressure current of raw oil, which was used to spray the walls of clean holding. In contrast to seawater, oil acts as a meltsSubsky and dissolves a solid oil sediment back into liquid oil. Instead of unusable water and oil emulsion, it is the result of raw oil that can be drawn to the shore and sold along with the rest of the cargo.

Due to the environmental benefits of oil washing, it has become the only legal method for cleaning the storage tanks of large oil tankers. In 1978 it was necessary for all new oil tankers to wash oil and those with a capacity of 20,000 tons or higher, which must be built with specialized oil washing systems. This requirement, together with the creation of segregated ballast reservoirs, which prevents the connection of ballast water and oil, significantly reduced pollution associated with international oil trade.