In this article, I will share several ash handling systems and how they work.
Ash handling systems are essential in ensuring the ash is carefully removed from the furnace and disposed of.
I already talked about the requirements of these pieces of equipment that they should fulfil to be considered effective for use.
You might like this: Requirement Of Ash Handling Equipment
The ash handling system consists of different units or components brought together to eliminate the ash from the furnace and dispose of it where it’s supposed to.
These systems make it possible for the quick handling of ash in large and medium power plants.
Without wasting time, let me share with you the ash handling systems and how they operate.
In this article, I will discuss the following ash handling systems and their working principles;
- Hydraulic ash handling system.
- Water jetting ash handling method.
- Ash sluice ways and ash lump handling system.
- Pneumatic ash handling system.
- Mechanical ash handling system.
1. Hydraulic Ash Handling System.
The hydraulic ash handling system is generally used in large power plants where there is production of ash in large quantities.
In most cases, steam power plants usually produce large quantities of ash, this type of system is highly likely to be used there.
You might like this: Steam Power Plant: Introduction, Components And Working Principle
There are mainly two types of hydraulic ash handling systems which are used in large power plants.
These systems are chosen depending on the characteristic of ash removal.
There are low and high-pressure hydraulic ash handling systems; the low-pressure hydraulic ash handling system is used in the continuous removal of ash from the furnace.
This system is highly preferred in a power plant where the furnace works throughout the day without stopping.
If the furnace will keep on working throughout the day, this means that the ash will be continuously produced.
With the low-pressure hydraulic ash handling system the ash will be taken care of easily without any issues.
The high-pressure hydraulic ash handling system is used for intermittent ash disposal.
This kind of system will dispose of ash and stop, wait for another fresh volume of ash to accumulate in the furnace and dispose of it again.
This high-pressure hydraulic ash handling system will start and stop when it comes to ash disposal.
The Working Principle Of Hydraulic Ash Handling System
The working principle of a hydraulic ash handling system depends on water moving under high velocity and pressure to carry the ash from the furnace and to the sumps.
This is how the hydraulic ash handling system works; the ash from the furnace grate falls into a system of water with high velocity and pressure where the ash is taken to the sumps.
The water and ash are separated in the sumps; the water is taken back to the circulation system, charged with high pressure and velocity and reused again in carrying the ash from the furnace.
The ash from the sump that is now separated from water is loaded in wagons, rail cars or trucks by a belt conveyor and a grab bucket and then taken to the dumping site.
To reduce the movement in the hydraulic ash handling system, an ash basement with an ash hopper can be designed in such a way that the ash from the sump falls directly into it and gets filled in a wagon or truck and transported to the dumping site.
The belt conveyor will not have to be used in this case which it’s highly preferred if there is not enough space to install the belt conveyor or the grab bucket to be used in loading the ash into the trucks.
2. Water Jetting Method Of Ash Handling Working Principle
The water jetting method of ash handling is simple since it consists of a few components; quenching nozzle and trough.
This is how the jetting method of ash handling works; the quenching nozzle is placed at the end of the stoker side where the ash will be falling from, and the low-pressure jet of water coming from the nozzle is used to cool the ash.
The ash falls in a trough and it’s then removed. That is how simple the method is.
This method of ash handling is preferred where the budget is low, a simple design is needed, a simple ash handling method is needed and where a small quantity of ash is produced.
3. Ash Sluice Ways And Ash Lump Handling System.
This system of handling ash is a bit complicated compared to all the systems I will discuss in this article.
Before I share with you how this type of system operates, let me craft for you the essential components and state their functions.
In this way, it will be easier for you to follow along when I describe how the overall ash handling system works.
Don’t be confused with the ash sluices simply because it only means ash channels.
Essential Components Of Ash Sluice Ways And Ash Lump Handling System
These are the main components of ash sluice ways and ash lump handling systems;
High-pressure water pump; it’s used to pressurize the water jet in the piping systems that are used to carry the ash from the furnace.
Without the high-pressure water pump, the whole system will be rendered useless.
The entire functionality of this system of ash handling depends on the effectiveness of this pump.
Ash sluices or ash channels; are the ways constructed at the bottom of the ash sump which is fitted with a screen where the ash is removed by the high-pressure water jet.
Ash sump fitted with a screen; it’s used to collect all the ash from the furnace and the screen divides the ash into compartments of coarse and fine.
Dust sump; it’s where the fine ash that was divided by the screen goes into.
This is a different sump from the main one that contained coarse and fine ash.
Dust slurry pump; it’s used to carry the fine ash from the dust sump via a dust pump to the point of disposal.
Ash feeding nozzle (AFN); it’s the nozzle that is used to feed ash to the sump via the sluices (channels).
Subway booster nozzle (SBN); it’s used to pressurize the ash from the ash sluices by high-pressure water jet that results in its separation of fine and coarse ash.
Draining Apron; it’s used to drain water from the coarse ash.
Dust delivery; take the ash out of the handling system to the disposal site.
Working Principle of Ash Sluice Ways And Ash Lump Handling System.
The working principle of ash sluice ways and ash lump handling systems depends on the high-pressure water jet to remove ash from the furnace bottom through the ash channels.
This is how the ash sluice ways and ash lump handling system works; the ash from the furnace falls by gravity to the bottom of the furnace and enters the ash sluices through the ash feeding nozzle (AFN).
The ash-feeding nozzle also controls the amount of ash entering the ash sluices.
Too large an amount of ash entering the ash sluices at once will reduce the efficiency of the separation of fine and coarse ash.
A high-pressure water pump is turned on and pressurizes the water in the piping system forming high-pressure water jets that carry ash from the furnace bottom through the ash sluices (channels).
As the ash is removed from the sluices, the subway booster nozzle is opened and a high-pressure water jet is used to push the ash forward to the ash sump that is fitted with a screen.
The screen divides the ash in the sump into two compartments of fine and coarse ash.
The screen acts as a filtration channel that separates the ash. The smaller particles of ash (fine) pass through the screen to the dust sump while the bigger particles of ash (coarse) remain on the other side of the screen.
This is necessary to make it easier to handle the ash without making a mess in the power plant.
A dust slurry pump is used to carry the fine ash from the dust sump to the disposal site via the suction pipe and dust delivery. The coarse ash is removed from the ash sump by an overhead crane with a grab bucket.
The draining apron is used to drain water from the coarse ash as it’s being taken out of the ash sump on the other side of the screen (coarse side).
4. Pneumatic Ash Handling System.
The pneumatic ash handling system is pretty simple compared to ash sluice ways and ash lump handling systems.
From its name, it suggests that the entire hash handling system is made functional by the use of air or steam that is under a high velocity.
These Are The Main Components Of the Pneumatic Ash Handling System And Their Functions;
The crusher; it’s used to crush the large ash particles into smaller particles.
The ash separator; it’s used to separate the ash from the air or steam (in case steam is used to convey the ash through the system) before it’s exhausted out of the system.
The high-pressure pump; it’s used to drive the high-velocity air or steam to convey the fine ash through the entire system.
The ash hopper; it’s used to collect the ash from the entire system and dispose of it where it’s required.
The filter; it’s used to clean the air leaving the system. The air leaving the system should be dust free to minimize air pollution.
The exhauster; it’s a fan used to extract the air from the pneumatic system.
Working Principle Of The Pneumatic Ash Handling System
The ash from the boiler furnace falls into the crusher by gravity, the large ash particles are crushed into smaller particles.
The high-pressure pump drives the high-velocity air stream (steam can also be used) through the crusher carrying away the ash particles to the ash separator.
In the ash separator, the ash is separated from the high-velocity air stream (or steam) and then conveyed to the ash hopper where it can be fed to the trail cars, wagons or trucks and taken to the dumping site.
The air separated from the ash is then exhausted out of the pneumatic system by the exhauster after it has been cleaned of the dust in the filter.
This is to ensure that the air leaving the system is clean and it also prevents the blades of the exhauster from corroding.
You might like this: Methods Of Controlling Gaseous Pollutants (Ultimate Guide)
And that is how the pneumatic ash handling system works.
5. The Working Principle Of Mechanical Ash Handling System.
This system uses the mechanical side of things to handle the ash from the boiler furnaces.
This is how the mechanical ash handling system works; the ash from the boiler furnaces falls on a trough containing water, the water seal cools the ash and delivers it to the belt conveyor. The belt conveyor moves the cooled ash from the trough water seal cooling unit to the ash bunker or a bin.
From there, the ash is fed into trucks or wagons and taken to the dumping site.
That is how simple the working principle of a mechanical ash handling system is.
Lastly…
I have done my best to explain to you how the ash handling system works, if you want to know more about a specific system you should do more research about it.
There is a lot to learn from these systems, just consider this article as a spark of curiosity.
If you have any additional points you would like me to add to this article don’t be afraid to let me know.
Thanks for reading, see you in my next article. Hope you enjoy learning about the ash handling system.
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