Diesel fuel storage, supply and applications

The fuel storage and supply system receives, stores, cleans and delivers fuel oil to the engine cylinders in the correct quantity, at the correct time and in atomised form.

Sketch

 Tanker -> Strainer -> BULK STORAGE TANK
                          |
                   Transfer pump
                          |
                       Filter
                          v
                      DAY TANK (overhead)
                          | gravity
                     Fine filter
                          v
                 FUEL INJECTION PUMP <- Governor
                          | high pressure
                          v
                 INJECTORS (in cylinders)
                          |
        leak-off oil -----+--> back to day tank

Working

1. Unloading and storage: oil brought by tankers or rail wagons is pumped through a strainer into large bulk storage tanks (steel, above or below ground), holding one to several months' supply. Tanks have vents, level gauges and drain valves for water and sludge.
2. Transfer: a transfer pump moves oil from the bulk tank through filters to the day tank, which holds about 8–24 hours of consumption and is placed above the engine so oil flows by gravity.
3. Filtration and heating: fine filters (and centrifuges for heavy oil) remove dirt and water. Heavy oils are heated to reduce viscosity.
4. Injection pump: a plunger-type pump raises the pressure (about 100–200 bar or more) and delivers a metered quantity, controlled by the governor according to load.
5. Injector: sprays finely atomised oil into the hot compressed air near the end of compression, where it self-ignites.
6. Surplus/leak-off oil returns to the day tank.

Injection may be by common-rail, individual pump or distributor system.

Applications of diesel power plants

• Standby (emergency) plants for hospitals, telephone exchanges, data centres, airports, industries.
• Peak-load plants working with hydro or steam stations.
• Base-load plants in small isolated areas where hydro or grid supply is not available.
• Mobile plants (trailer-mounted) for construction sites, mines, temporary loads and relief work.
• Starting stations (black-start) for large steam and gas stations.
• Nursery stations in growing towns before grid extension, and supply on islands, hilly and remote areas.
• Captive power for industries where load-shedding occurs.