Operation and Maintenance (O & M) of Ash Handling System ...

27 May.,2024

 

Operation and Maintenance (O & M) of Ash Handling System ...

Are you looking for comprehensive information about the Ash handling system in Thermal power plants including its Operation and Maintenance (O & M)? If indeed, you are at the right place and do read this article till the end.

If you want to learn more, please visit our website ash handling pump.

Let&#;s get started&#;!

Introduction: Ash Handling System in Thermal Power Plants

One of the most profound and earliest methods of generating electrical power from available resources is the conversion of thermal energy released by the burning of an organic fuel in a thermal power plant.

It is still a dilemma as energy production through thermal power plants leaves many waste elements, which can create harmful effects if not handled properly. In spite of this, thermal power stations are contributing a significant part in fulfilling the energy requirement of this world.

According to a paper published in , typically for a 2×500 MW plant based on Indian coal, the ash generated is around 300 to 400 TPH, although the figure depends upon the gross calorific value as well as the content of the ash.

An Ash handling system in thermal power plants is an advanced technological method to control and manage the production of ash &#; one of the waste elements in every thermal power station. The hot residual ash is cooled down to a specific controlled temperature and stored properly through compliant systems.

Rather than disposing of this ash as a waste, an ash handling system helps recycle, store, and use it in different industries, including cement plants, construction sites, and allied industries. Hence, proper O & M of an ash handling system is of significant importance in any thermal power plant to improve its efficiency and production.

Operations in an Ash Handling System of Thermal Power Plants

An ash handling system involves the following critical operations. Mishandling in any phase can critically harm the operation of the whole system.

1. Removal of Ash from Furnace

When the fuel, let&#;s say coal, is burnt in the furnace of any thermal power plant, it produces a large amount of ash that needs to be removed. For many evident and technical reasons, it is incredibly harmful to keep that hot residual of ash in the furnace.  Some of them are given below:

  1. Residual ash covers a significant volume of the furnace, which will impact the intake of fuel.
  2. Hot ash can cause wear to the inside structure of the furnace due to its corrosive nature.
  3. The efficiency of the furnace and the burning of fuel are affected.

2. Quenching Process

To prevent such consequences, ash is removed from the furnace and is quenched (passed through or dipped in water) in a separate container. The quenching process is done for the following reasons:

  1. Reduce the temperature of ash up to a manageable degree
  2. Lessen the corrosiveness of the residual ash
  3. Prevent ash particles from scattering
  4. Avoid the formation of clinkers

3. Transportation of Ash

After the quenching process is finished, the ash is then transported to another storage. This transportation can be carried out by four different means, depending on the plant&#;s requirements. Either of the following systems can drive the conveyors used to transport the ash in an ash handling system of a power plant:

  1. Mechanical System
  2. Pneumatic System
  3. Hydraulic System
  4. Steam-injector System

4. Collection in Ash Bunkers

Using any of the above-mentioned means of conveyor transportation systems, the ash is stored in ash bunkers. The ash can be used for various purposes (in the manufacturing of cement or construction sites) or disposed of in ponds when it settles down in the base.

NOTE: Some dust particles from ash enters the piping system, implanted to remove the residual gases. These particles are separated out in a dust collector. This dust collector prevents those corrosive and harmful particles from releasing into the environment and collecting them in a separate space.

Types of Ash Handling Systems and their Operations

Depending upon the nature of collecting and processing ash, the ash handling systems are mainly of two types.

  1. Fly Ash Handling System
  2. Bottom Ash Handling System

1. Fly Ash Handling System

The operations in a fly ash handling system consist of an ESP (electrostatic precipitator) ash system, an economizer ash system, and an air-preheater ash system.

The compressed air from compressors is transferred through pipes to the ash systems. A valve inside the pump allows the ash, collected in the hopper, to enter. The ash is then carried away through the pipers with the help of compressed air. This electrostatic precipitated ash is then transferred to the ash silo. Similarly, the economizer ash and the air-preheater ash is sent to the ash silo by the help of compressed air.

  • Economizer ash particles have no typical size. The temperature of this ash ranges from 600°F to 900°F.
  • In the air preheater system, the particle sizes range from 100 to 800 microns, while the ash temperature ranges from 250°F to 400°F.
  • In the case of the Electrostatic precipitator ash handling system, the size of the fly ash particles entering the ESP can range from 0.01 micron to microns.

2. Bottom Ash Handling System

The operations involved in a bottom ash handling system include the collection, cooling, and crushing of the furnished bottom ash. After these operations, the ash is collected into a bottom ash bunker. The ash that drops from the hot boiler is conveyed to a crusher using a conveyor belt sunk into the water at 60 degrees. The crusher breaks down the clinkers and turns them into fine particles, which are stored in the bottom ash bunker. For the bottom ash handling system, an ash hopper&#;s optimum storage capacity is in the range of 10 to 12 boiler hours&#; output.

Bottom Ash Handling System

The ash from both, ash silo and bottom ash bunker, is then carried away by trucks or railways to their destined location to different plants.

Maintenance in an Ash Handling System of Thermal Power Plants

For any power plant to operate normally, proper handling and maintenance play a vital role. It is critical to check if all the equipment is following the same and the standard operating cycles. Failure in a single piece of equipment can lead to the system&#;s collapse, which may cause significant damage.

Here are some points that we carefully deem regarding an ash handling system of a thermal power plant.

1. Checking the wear in Bottom Ash Hopper

  1. Falling of clinker ash pieces in the hopper can damage the lining.
  2. There are chances of wear inside the flushing nozzles in the ash hopper.
  3. Incorrect alignment of nozzles can cause an erosional effect.
  4. Ash accumulation can distort the seal plate.

2. Maintenance of Clinker Grinder

  1. A high concentration of ash in the slurry can cause a clinker grinder to stall.
  2. The grinder would stop working if excessively packed material, pieces of slag, or erection debris entered.

3. Replacing worn parts of Jet pumps

Jet pumps require a sure concentration of ash to work at an optimum level. In case any jet pump wears from any part (body, tube, or nozzle), it is needed to be replaced urgently.

4. Prevention from Corrosion

It is necessary to use corrosion-resistant parts for hopper, discharge gate, jet, and grinder. The hopper water with a pH of 5.5 and corrosion can produce failure in the systems.

5. Taking Care of Pipelines in a pneumatic ash handling system

Preventive measures should be taken for the following causes:

  1. Incorrect Air Mover Specification
  2. Over Feeding of Pipeline
  3. Moisture in Line
  4. Pipeline Wear
  5. Wear of Straight Pipeline
  6. Leakage

Conclusion

Operations and maintenance (O & M) of an ash handling system in any thermal power plant is one of the crucial aspects. Whether it&#;s the proper functioning of a thermal power plant, achieving optimum efficiency, or making a process environment friendly, normal operations and timely maintenance of an ash handling system are critically important.

Depending upon the type of plant and its specific requirements, O & M of an ash handling system varies, but properly operated and well-maintained equipment ensures higher internal plant efficiency and optimized costs, notwithstanding higher project returns for the thermal power plant.

Hope you found this guide useful. Kindly subscribe to our newsletter and also share it with your friends and industry colleagues on Facebook, Twitter, and LinkedIn!

How has your experience been so far on this subject? Kindly share your thoughts in the comments!

PS &#; for any type of Operations & Maintenance requirement in your thermal power plants, please do get in touch with us. We are a team of experienced engineers who are the doyens in this field for the last two decades. We would be happy to add value to your process.

Ash Handling System | Thermal Power Plant - WordPress.com

What is Ash?

The company is the world’s best centrifugal sand dredging pump factory supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

  • Ash is the residue remaining after the coal is incinerated.

Composition of ash handling system?

  • SiO2, Al2O3, Fe2O3, CaO , MgO.

Why Ash Handling System is required?

  • In Thermal Power Plant&#;s coal is generally used as fuel and hence the ash is produced as the byproduct of Combustion. Ash generated in power plant is about 30-40% of total coal consumption and hence the system is required to handle Ash for its proper utilization or disposal.

Ash terminology in power plants?

  • Fly Ash ( Around 80% is the value of fly ash generated)
  • Bottom ash (Bottom ash is 20% of the ash generated in coal based power stations.

What is fly ash?

  • Ash generated in the ESP which got carried out with the flue gas is generally called Fly ash. It also consists of Air pre heater ash & Economiser ash (it is about 2 % of the total ash content).

What is bottom ash?

  • Ash generated below furnace of the steam generator is called the bottom ash.

 

Volume of ash and properties

 

 

System Description

The ash handling system handles the ash by bottom ash handling system, coarse ash handling system, fly ash handling system, ash disposal system up to the ash disposal area and water recovery system from ash pond and Bottom ash overflow. Description is as follows:

 

  1. A.      Bottom Ash Handling System

Bottom ash resulting from the combustion of coal in the boiler shall fall into the over ground, refractory lined, water impounded, maintained level, double V-Section type/ W type steel- fabricated bottom ash hopper having a hold up volume to store bottom ash and economizer ash of maximum allowable condition with the rate specified. The slurry formed shall be transported to slurry sump through pipes.

  1. B.      Coarse Ash (Economizer Ash) handling System

Ash generated in Economizer hoppers shall be evacuated continuously through flushing boxes. Continuous generated Economizer slurry shall be fed by gravity into respective bottom ash hopper pipes with necessary slope.

  1. C.      Air Pre Heater ash handling system

Ash generated from APH hoppers shall be evacuated once in a shift by vacuum conveying system connected with the ESP hopper vacuum conveying system.

 

  1. D.      Fly Ash Handling System

Fly ash is considered to be collected in ESP Hoppers. Fly ash from ESP hoppers extracted by Vacuum Pumps up to Intermediate Surge Hopper cum Bag Filter for further Dry Conveying to fly ash silo.

Under each surge hopper ash vessels shall be connected with Oil free screw compressor for conveying the fly ash from Intermediate Surge Hopper to silo. Total fly ash generated from each unit will be conveyed through streams operating simultaneously and in parallel.

  1. E.       Ash Slurry Disposal System

 

Bottom Ash slurry, Fly ash slurry and the Coarse Ash slurry shall be pumped from the common ash slurry sump up to the dyke area which is located at a distance from Slurry pump house.

Related Pages

Rate this:

Share this:

Like

Loading...

If you are looking for more details, kindly visit centrifugal sand dredging pump price.