Crude Oil Washing System

Crude oil washing (COW) is rinsing the residue from the storage tanks of an oil tanker using the crude oil cargo itself, after the cargo storage tanks have been cleared. Crude oil is pumped back and preheated in the slop tanks, then sprayed back through high tension nozzles in the freight storage tanks onto the walls of the tank. Due to the sticky nature of the crude oil, the oil hold on to the storage tank wall surfaces, and such oil adds to the cargo 'Remaining on board' (the ROB). By COW the containers, the amount of ROB is substantially reduced. With the existing high expense of oil, the financial savings are substantial, both for the Charterer as well as the Ship owner. If the cargo ROB is regarded as 'liquid and pumpable' then the charterers could assert from the owner for any cargo loss. It replaced the lots on the top and seawater washing systems, both of which involved led releasing oil-contaminated water right into the sea.

History

Even with load on top there is still some oil in the released water from the slop tank. Beginning in the 1970s, efficient tools using crude oil itself for washing started to change the water-based cleaning, resulting in the existing technique of crude oil cleaning. This minimizes the remaining deliberate discharge of oil-contaminated water as well as raises the amount of cargo discharged, supplying an additional benefit to the cargo proprietor.

Modern vessels likewise use segregated ballast storage tanks and these eliminate the issue of discharge of oily ballast water.

Crude oil cleaning (COW) is a system where oil tanks on a tanker are cleared out between voyages not with water but with crude oil - the cargo itself. The solvent action of the crude oil makes the cleansing process far more effective than when water is made use of. (There is normally a final water rinse but the amount of water involved is reduced.) The system helps avoid contamination of the seas from operational measures.

Disadvantages with Water Washing

As vessel sizes increased and also much more strict policies versus oil pollution were applied, it was understood that water washing alone is an inferior container cleaning approach. WHOLE LOT (Load On Top), no matter how full and advanced it may be, can never eliminate the great disadvantages with water cleaning compared to COW:

 Longer time for washing each storage tank, leading to maximized bunker expenses.

 Handling bigger quantities of water is expensive and also induces maximized pollution of the sea given

    that the water is contaminated with oil, even when WHOLE LOT procedures are utilized.

 Increased rust as a result of substantial water washing.     

Development of Crude Oil Washing

The introduction of load on top was a good contribution to the fight versus aquatic pollution but it did not entirely get rid of contamination arising from storage tank cleaning operations. Although the quantity as well as rate of discharge is carefully managed, the process still resulted in some pollution occurring. In the late 1970s an improvement was presented. Instead of using water, the container cleaning machines relied on crude oil - in other words, the cargo itself. When shot into the debris holding on to the storage tank walls, the oil merely liquefied them, turning them back right into usable oil that can be pumped off with the rest of the cargo. There was no requirement for slop tanks to be utilized since the process left virtually no slops. The process ended up being referred to as Crude Oil Washing (COW). Crude Oil Washing indicated that the mixture of oil and water, which previously resulted in a lot functional pollution, was practically ended. At the same time, the proprietor is able to release far more of this cargo than previously, considering that much less of it is left holding on to the storage tank wall surfaces and bottoms.

 Advantages COW

Since that equipment and treatments are well adapted for COW, the following advantages are obtained in contrast with water washing:

Substantial reduction in air pollution capacity since less oil continues to be aboard after discharge and also much less oil-contaminated water is handed throughout the ballast passage.

* Reductions in time and price of container cleansing.

* Desludging manually prevented.

* Minimized container cleansing time at sea.

* Boosted out-turn of payload.

* Decreased dead freight as less oil-water slops are kept on board.

* Less seawater discharged to refineries.

* Decreased storage tank rust caused by water washing.