The tanks are cleaned with a machine called a Butterworth or Gamajet. Regardless of the actual manufacturer they are almost universally called Butterworth Machines.
These machines shoot hot crude oil onto the sides of the tanks so that it washes the sediment down to be pumped out.
The tanks must be cleaned before they can be inspected, and before cargo of a different type is loaded.
get it from places like Africa who send it to UK in tanker ships along the sea
MR oil tanker actually refers to Medium Range Product Tanker which is between 42,000 dwt to 59,999 dwt. There are two categories of ships in the oil tanker industry. First are the Product tankers which transport refined petroleum products like gasoline, diesel, naphtha, aviation fuel, etc. Second are the Crude carriers which transport unrefined crude oil.
introduction of inert gas in inerted tank ...
Tanker takes over
An oil tanker would be carrying crude oil, not refined product. So the answer would be zero.
a tanker
Yes.
Jahre Viking, crude oil tanker
crude
Pipelines are the safest way to transport fuel, oil, etc.
You call a ship that is built to transport oil a tanker.
It can go via pipeline to an onshore facility for refining or storage, it can go to and FPSO (A floating production, storage and offloading vessel anchored in the vicinity of the oil rigs) where it could be pumped into oil tanker ships, or to a man made island where it is stored and pumped into oil tanker ships. The oil eventually ends up in refineries where fuels, lubricants, plastics, chemical, rubber, and other bi-products are then manufactured.