Have you ever wondered how electricity reaches our homes? This complex process goes through many stages, out of which coal handling plant is the most important. Let us understand in simple language how it works.
Coal handling plant is actually the beginning of the process of generating electricity. The main work of this plant is to receive coal, process it, store it and finally deliver it to the boiler. In the boiler itself, coal is burnt to produce steam, which is used to generate electricity.
Coal Handling Plant in Thermal Power Plant involves the following step by step process
1. Unloading process:
Coal is transported to a coal handling plant by 2 main methods:
- Train: Most coal is transported to a coal handling plant by trains from distant mines.
- Truck: In some cases, coal is also transported by trucks if the mine is nearby.The techniques used to unload coal at a coal handling plant depend on the mode of transport of coal.
Unloading Coal from Trains
Two main methods are used to unload coal from a train:
1.Wagon Tippler: This is a very large machine with rail tracks attached to it. Train carriages are brought to this machine. Then, the machine rotates these carriages and tilts them by about 135 degrees, causing the coal to fall straight from the carriages into the hopper below. The hopper is a large funnel-like structure from where the coal is taken for further processing.
2.Track Hopper: Some plants use special containers with an open bottom. These are called “Bogie Open Bottom Discharge (BOBR)” containers. These containers are brought directly over the pit-like structure (track hopper) built on the railway track. Then, the bottom of the container is opened and the coal is poured directly into the track hopper. The coal is also taken out of the track hopper for further processing.
2.Screening and crushing:
Some coal pieces may be very large. Therefore, large pieces are separated with the help of sieves (screens) in the plant. Then the large pieces are broken into suitable sizes with machines called crushers.
3.Stacking & Reclaiming
Finished coal has to be stored in heaps. Large storage areas or stack yards are used for this.
When required, the stored coal is taken out through a conveyor and taken to the bunker. This process is called “reclamation”.
4.Bunkering
In this process, finished coal is unloaded into the boiler bunker through a conveyor with the help of a tripper trolley. Bunkers are actually very large funnels or hoppers like structures. Coal keeps accumulating in them continuously. The boiler operator takes out coal from the bunker as per requirement and puts it in the boiler for burning.
Coal Handling Plant Layout
which type of coal is used in thermal power plant
Bituminous Coal: This is the most commonly used coal. The carbon content in it ranges from 75% to 90%. The average calorific value of bituminous coal is 33500 KJ/Kg.
Sub-bituminous coal: It is black in color and has slightly less energy than bituminous coal, it can also be used for power generation. Sub-bituminous coal is processed before burning, so as to increase its efficiency.
Anthracite Coal: This is the highest grade coal, this coal is black shiny and hard, brittle, often called hard coal. It has a carbon content of up to 90%, its calorific value is 36000 KJ/Kg.
Lignite Coal: This is the lowest grade coal which is also called brown coal, it has the lowest carbon content. Lignite coal also has high moisture content, its calorific value is 25000 KJ/Kg.
Type of Grade coal used in coal handling plant
| Grade | Calorific Value (KJ/Kg) | Moisture (%) | Use in Coal Handling Plant |
|---|---|---|---|
| A – Anthracite | 36,000 | 2.0 | Primary Coal for Power Plants |
| B – Bituminous | 33,500 | 8.0 | Suitable for Power Plants (blended) |
| C – Sub-bituminous | 30,000 | 15.0 | Suitable for Power Plants (blended) |
| D – Lignite | 25,000 | 30.0 | Industrial Use |
| E – Peat | 23,000 | 50.0 | Not Suitable for Industrial Use |
| F – Not Suitable | 0 | 0.0 | Not Suitable for Industrial Use |
As you can see, the grade of coal is determined by its calorific value and moisture content. Anthracite (A) has the highest calorific value and lowest moisture content, making it the most desirable coal for power plants. Peat (E) has the lowest calorific value and highest moisture content, making it unsuitable for most industrial applications.
Types of Plant Maintenance in Coal Handling Plants
- Preventive Maintenance:
This is the most important maintenance. It involves taking care of the machines beforehand. Just like putting oil in a car regularly, similarly, the machines in the plant also have to be lubricated regularly so that the friction is reduced and they can run smoothly. Apart from this, the machines are inspected from time to time to see if there is any defect. If any part is worn out or about to break, then it is replaced in time. Also, vibration analysis is also done in the machines, so that any kind of problem can be detected beforehand.
- Breakdown Maintenance:
This happens when a machine suddenly breaks down and stops working. Then this machine is repaired. But, this maintenance is not considered good because it can also stop the work of generating electricity. Therefore, efforts are always made to minimize such situations.
- Predictive Maintenance:
This is a new technology in which the condition of the machines is detected with the help of sensors installed in them. With the help of computers, it is known whether any problem is going to occur in the future or not. If it is going to occur, then preparations are made to repair it in advance.
- Overhauling:
Some machines are completely opened from time to time and their complete inspection and repair is done. In this, all the parts of the machine are examined and they are repaired or replaced as per their need.
- Safety Inspection:
Safety is the most important thing in a coal plant. Therefore, to ensure that all machines and processes are following the safety rules, safety inspection is done regularly. These checks include checking of escape routes in case of fire, checking of fire extinguishing equipment and checking of safety equipment of the employees.
So overall, many types of maintenance works are done to keep the coal plant running safely and smoothly. These maintenance works play an important role in increasing power generation and running the machines for a longer time.
Very informative article 👌