What precaution must be taken with the source tank when using a crude oil washing system?

When using a crude oil washing (COW) system, it is essential to ensure that at least one meter must be decanted from the source tank. This precaution is vital because it helps to maintain a sufficient volume of oil in the tank, which is necessary for the effective operation of the washing system and to avoid damaging the tank's structure or equipment.

Decanting at least one meter creates a safety buffer, allowing the remaining oil to provide adequate coverage and preventing air from entering the tank during the washing process. This minimizes the risk of creating an explosive atmosphere and ensures that contaminants are effectively washed out of the tank. By maintaining this level, the system can operate efficiently and safely, ensuring that the crude oil washing process is effective while adhering to safety standards and operational protocols.