Diesel Power Plant

DIESEL POWER PLANT

Power unit of a Diesel Power Plant is mainly a diesel engine. Usually a multicylinder diesel engine is coupled to an electrical generator to serve as a power unit. Diesel Power Plant is chiefly used as a peak load and stand by unit for the hydro-electric power plants. It is used as an energy stand by unit which normally remains idle and is run only when there is failure of central station.

Elements or Components of a Diesel Power Plant

Major components of a Diesel Power Plant and their functions are

Engine : The main element of power plant. It is a prime mover. It may be a 4-stroke or 2-stroke multicylinder engine.

Engine Air Intake System : It includes air compressor, filters, ducts etc., Required quantity of air for combustion of fuel is supplied by this system. Nearly 4 to 8 m3 air per kWh of plant capacity is required.

Fuel System : It includes main fuel storage tank, daily consumption tank, fuel transfer pumps, filters, injector etc. This system ensures supply of right quantity of fuel through fuel injector.

Engine Exhaust System : It comprises exhaust manifolds, ducts, silencers etc. A muffler or silencer in the exhaust line reduces pressure and noise level. This system ensures effective exhaust or scavenging of burnt gases from engine to atmosphere.

Engine Cooling System : Engine cylinders are surrounded by cooling water. Radiators, Evaporative Coolers or Cooling Towers may be used to cool down the warm, jacket water and recirculate the cool water around cylinders. Cooling water temperature must be controlled. When too low, the lube oil will not spread properly and will result in cylinder and piston wear; when too high, the lube oil will burn. It is necessary to keep the exit temperature of cooling water around 70°C. For a temperature rise of 10°C, nearly 2 to 4 litre per brake power per minute is required.

Engine Lubrication System : It consists of filters, lube oil pump and oil cooler, piping etc., lubricating system is of great importance for diesel engines in heat dissipation as well as lubricating the cylinders, pistons, bearings, etc.

Engine Starting System : Because of high compression pressures, diesel engines cannot be started easily by hand cranking, Various methods used for starting are

• compressed air starting

• electric motor starting

• auxiliary engine starting .

Advantages and Disadvantages :

Advantages :

• relative small size for the same capacity

• easy cold starting

• quick application of load

• reduced stand by losses

• thermal efficiency is higher than steam or hydro power plants of same capacity

• low requirement of make up water for cooling purpose

• easy transport and storage of diesel oil