Marine diesel engines are designed to burn heavy residual fuel. This is made up of the residues after the lighter and more costly fuels and gases have been taken out of the crude oil at the refinery. The graphic below illustrates the process
The diagram below shows a Fuel oil supply system for a large 2 stroke crosshead engine. However the set up is typical of any fuel system for a marine diesel engine operating on heavy residual fuel.
For an explanation of each of the components, place the mouse arrow on the component and click.