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Oil Power Plant

July 11, 2020
Diesel power plant

An oil power plant or standby power station is the plant that uses the oil engine as a prime mover. It also combines an oil engine with an electric generator to produce electrical energy using oil fuel or liquid fuels like natural gas.

It is generally a compact station so it can be located when we actually require it.

And the oil power plant produces limited amounts of electricity.

Additionally, it acts as an emergency supply station for many countries and produces power in the range of 2 to 50 MW.

As a standby set, it can supply power during peak periods. For instance, places like hospitals, radio stations, telephone exchanges, industries, cinema theatres, and very suitable mobile power generation, railways, and ships.

Oil Power Plant Working Principle

The working principle of the oil power station is straightforward. Firstly, we compress the air in a cylinder to raise the temperature until the oil inside the engine burns. The combustion produces the working fluid at high temperature and high pressure to convert the heat energy into mechanical energy.

And as the oil engine acts as a prime mover, it rotates the electrical generator’s rotor and converts this mechanical energy into electrical energy.

This working principle is a cycle done by the processes: intake, compression, expansion, and exhaust.

Components of Oil Power Plant

The oil power station consists of many components to achieve the best of the plant. Let us illustrate:

Engine

It is the main part of the plant for producing the power, and it may be of the two-stroke or four strokes.

Fuel Supply System

It consists of a storage tank where we store the oil from the plant.

It involves the fuel tank where the oil pump for usage, strainer, which we use to remove suspended impurities of the oil, and fuel injection (transfer) pump, is used to inject the clean oil into the engine.

Strainer

We use it to remove solid impurities from the oil transferred from the main tank to a small dry tank through this strainer.

Air Intake System

We use it to remove the dust particles from the atmospheric air to supply fresh air to the engine for combustion. It may be a dry (or oil) bath filter or oil-immersed filter, and it consists of pipes to supply the fresh air and filters to remove dust particles from the air.

Exhaust System

We use it to remove the exhaust gas from the engine to the atmosphere, and we also add a silencer to this system to reduce the system’s noise level.

Cooling System

It’s vital in the oil power station to have a cooling system to maintain the engine’s overall temperature at an agreeable level. This cooling system requires a water source, a water pump that circulates water through a cylinder, and cooling towers that we use to cool the hot water.

Lubricating System

We use it to minimize the wear of the engine’s rubbing surface as we store oil in a main lubricating oil tank then draw this oil from an oil pump to pass through the oil filter to remove impurities.

Engine Starting System

We use it in old conditions as a starter as it uses the air to push the engine and start an initial rotation until the engine run with its own power, and the starting methods may be:

Self-starters in small oil engines where the motor draws heavy current and is designed to work 30 Sec after being cooled continuously.

Auxiliary Engine

They are located close to the main engine and driven through a clutch and gears as the clutch disengaged to start the engine.

Compressed Air System

We use it in large oil engine, and it’s supplied from an air tank.

Governing System

It’s used to control the engine’s speed by changing the fuel provide according to engine load.

Oil Power Plant Layout

The layout of the oil power station illustrates the main and auxiliary components of the plant and the importance of each component as:

Oil Engine

The compression ignition engine consists of a cylinder, cylinder head, piston, inlet valve, an inlet port, exhaust valve, valve spring, cooling fins, wrist fines, wrist pin, connecting rod, crankcase, crank pin, crank, and crankshaft.

We classify them into two-stroke engine and four-stroke engines.

Engine Starting System

It is an arrangement to rotate the engine initially, and we use compressed air for starting the engine until it runs with its own power.

Fuel Handling System

We use trucks, railway wagons (barges), or oil tankers to deliver the fuel oil to the plant site. Engine day tanks deliver the oil to the main tanks, capable of storing oil equivalent to 8-hour consumption through strainers.

Liquid Fuel Handling System

And we heat the oil with hot water or steam to reduce viscosity and reduce the pumping power input.

Fuel Injection System

We can say that this system is the heart of the oil engine as it can be used as:

  • Firstly as a filter ensuring oil from dirt.
  • Secondly, meters the correct quantity of fuel to be injected into the cylinder.
  • Thirdly, it regulates the fuel supply.
  • Fourthly, atomize the fuel oil for better mixing with the hot oil.
  • Lastly, distribute the atomized fuel properly in the combustion chamber.

Air Intake System

It transfers fresh air through louvers and air filter to the cylinder by an intake manifold, and we can fit a supercharger driven by the engine between the filter and the engine to augment the power.

Exhaust System

Useful to discharge the engine exhaust to the atmosphere with minimum noise.

We use an exhaust manifold to connect the engine cylinder exhaust to the exhaust pipe. Thus, to demand the fluctuating pressure of the exhaust line with a muffler or silencer. In other words, reducing most of the noise that results when gases are discharged directly into the atmosphere.

Oil-Based Power Plant Exhaust System

There is also a flexible tubing system to expand and isolate the exhaust system from the engine vibration. And we may also use a heat recovery steam generator to generate low-pressure steam for process work.

Engine Lubrication System

It’s used to provide a sufficient quantity of cool filtered oil to give adequate lubrication to the engine’s moving parts. It consists of a lubricating oil tank, pump, filter, and oil cooler. It is classified into:

Mixed Lubrication System

It’s usually used in the two-stroke engine to mix a small quantity of lubricating oil in the fuel tank.

Wet Sump Lubrication System

This may be a splash system, pressure fed system, or splash or pressure feed system.

Dry Sump Lubrication System

It’s usually used in a large stationary marine engine where we carry the oil supply in an external tank with some help of a scavenging pump through a strainer and filter.

Cooling System

It consists of a water source, a pump that circulates water through a cylinder and head jacket; and a cooling tower to cool the hot water from the engine.

And we must take into consideration when we planning for the layout the following:

  • Firstly, the approximate dimensions of the equipment.
  • Secondly, the location of the equipment and the minimum clearance between each part.
  • Thirdly, natural lighting and proper ventilation provision.
  • Then again, the availability of future addition to the building with minimum changes.
  • Additionally, provision for installing at least one spare unit in the future.
  • Finally, provision for a small workshop, stores, office, and so on.

Application of Oil Power Plant:

Since oil power station has a capacity in the range of 2 to 5MW, it can be used in many applications such as:

  • A central station for medium or small power supplies.
  • And for emergency services as a standby plant to hydroelectric power plants and steam power plants.
  • Thermal or hydropower plants as a peak load plant in combinations.
  • For mobile power generation, transportation systems like automobiles, railways, airplanes, and ships.
  • A nursery station to transport the power from stations to small power plants or supply power to small towns.
  • It’s economical for industries where they require a small power in the order of 500 KW as it offers high overall efficiency.
  • For electrical power generation in capacities 100 to 500 H.P.

Advantages of Oil Power Plant

The oil power station is simple in everything; thus, it has many advantages, such as:

  • The low initial cost which makes it easy to install and commission it quickly.
  • The design is very simple and requires a small space.
  • It can start and stop with quick facilities, as small generators can start and stop in a few seconds without any standby loss in the system.
  • The thermal efficiency is quite higher than other types.
  • We can build it near the load center and don’t cause a problem with ash disposal exists.
  • The size of the plant is quite smaller than steam plants as they have the same capacity.
  • It’s easy to design it for portable use.
  • The cooling is easy and requires a small quantity of water.
  • There isn’t any difficulty with varying loads.
  • Also, the fuel cost required for operation is low.
  • Replacement losses are smaller.
  • And it also requires fewer members of engineers.

Disadvantages of the Oil Power Station

As we illustrate the advantages; we will also illustrate the disadvantages of the oil plant, which are:

  • The higher running costs due to the high cost of the oil.
  • The general use of this plant is to produce small power requirements.
  • It can’t stand up for a long period of overload conditions.
  • The lubricant cost is high.
  • Complex and high-cost maintenance, which makes the life of the plant small from 7 to 10 years.
  • Its capacity is only about 50 MW.
  • It isn’t easy to construct it on a large scale.
  • Also, the noise produced by the plant is high.

The Efficiency of the Oil Power Station

We all know that efficiency is the output of the process to the input, but here with power plants, we have three main types of efficiency, which are:

Economic Efficiency

This is the specific cost of production, which includes fuel, labor, materials, and services cost compared to the plant’s energy output for a definite period of time.

Operational Efficiency

It’s the capacity factor or load factor, which measures the plant’s actual output comparing to the potential maximum output.

Energy Conversion Efficiency

It closely relates to the heart rate, which is the electrical generator’s quantity of heat to generate 1 kWh of electricity.

So from all this information, we can say that the oil power plant’s overall efficiency is between 35-42%.