Disadvantages Of High Ash Content In Coal

In this article, I will share the disadvantages of high ash content in coal.


Knowing the negative effects of high ash content in coal is going to help you understand why one should always choose quality coal.


The coal with a high calorific value usually produces less ash compared to the coal with a low calorific value.


You might think that using cheaper coal with lower quality is saving you money, but it’s actually hurting you.


Without wasting time, let me share the disadvantage of high ash content in coal.


These are the disadvantages of using coal with high ash content;

1. It reduces the efficiency of the boiler.

This is the first disadvantage of using coal with high ash content.


The first thing you should keep in your mind is that coal that produces large amounts of ash when it burns has a lower calorific value.


If you know anything about boilers, their efficiency mainly depends on the amount of heat energy produced by the furnace.


For the boiler to be effective, quality steam needs to be produced.


That will only be possible if the amount of heat energy produced is enough to generate a large quantity of steam with the best conditions.


If the coal doesn’t deliver its end of the deal by producing the right amount of heat energy, the steam that will be generated will end up being of lower quality.


Low-quality steam hurts the efficiency of the boiler.


You might like this: How To Increase a Boiler Efficiency On A Budget


With incomplete combustion, a lot of heat energy is lost through the unburnt carbon.


The amount of heat energy lost also contributes to the decrease in the efficiency of the boiler.


The coals with high ash content will also lose high heat energy through the ashes.


In a furnace where a large amount of ash is produced, clinker formation is always going to be a chronic problem.


This also will end up decreasing the operating efficiency of the furnace and overall decreasing the efficiency of the boiler.


So, I think now you have an idea of the effect of high ash content in a lump of coal.


When selecting coal to be used in a power plant its properties should be checked thoroughly to ensure it won’t decrease the efficiency of the power plant.


You might like this: Properties Of Coal Selected For Steam Power Plants


2. It brings disposal issues.

To be honest ash handling tends to be hectic since this will be done as long as the power plant is operating.


So, if the coal that is in the furnace produces high ash content this will bring disposal issues.


The ash produced by the furnace is not so friendly to the operators or the environment.


If the ash is not handled carefully, it can end up destroying the entire working environment of the power plant.


The large quantity of ash produced by the coal will have to be removed from the furnace and taken to the dumping site.


If a large quantity of ash is produced, ash-handling equipment will be needed. These pieces of equipment will be available but at a cost.


The ash will need quenching before it’s handled, the equipment used to handle the ash will always need to be repaired and maintained.


You might like this: 5 Systems Of Ash Handling: Components And Their Working Principles and Requirement Of Ash Handling Equipment


Measures will have to be taken to prevent poisonous gases from the ashes and not harm the operators.


Considering all the things you have to deal with when handling a large amount of ash, it’s all chaotic.


So, when selecting coal to use in a power plant, one should keep in mind that handling ash is going to be a problem that they will have to deal with every single day.


3. It increases transportation costs.

Coal that produces a large amount of ash will always have a low calorific value.


If the coal will have a low energy value, this means that it will be needed in large quantities to meet the heat energy requirements in the power plant.


You have to know that the coal has to be transported from where it’s mined to the power plant.


The rounds that the trucks will have to take delivering the coal to the power plants are going to be more since a large amount of coal will be needed.


The low calorific value of the coal will have to be compensated by the large amount of coal being fed into the furnace.


But for the coal with a high calorific value, produces low ash content, it burns progressively in the furnace and less amount of coal will be needed.


The burning efficiency of coal with high calorific value will decrease the number of rounds the trucks will have to transport the coal.


This will end up decreasing the transportation cost.


4. It produces irregular burning which is hard to control.

The coal that produces high ash content doesn’t burn progressively and regularly.


The disadvantage of using coal with high ash content is that it will be very hard to control its burning.


The only way one will be able to manage to control the combustion of coal with high ash content is for it to be pulverized.


When it comes to pulverizing coal, additional operational cost is going to come in and that won’t be good for the power plant.


But for one to gain control of this type of coal, it will have to be pulverized since this is the only form that the combustion can be controlled by the burner.


You might like this: Advantages Of Using Pulverized Coal


By pulverizing the coal high thermal efficiency can be achieved by using coal with high ash content.


So, if you want to use low-quality coal because you want to save money, just know that you are going to use the money you saved to increase the overall efficiency of the burning system.




The tips I have shared in this article are just to give you a perspective of what would happen if coal of low calorific value is chosen to be used in a power plant.


So, before fuels are to be selected for use in the power plant, it’s better for the operators to sit down and reflect on the future.


They also have to consider the additional cost of the fuel once they start using it in the power plant.


What I think is that it’s always better to use maximum resources to ensure that the furnace is working to its full capacity.


That starts from its maintenance to the type of fuel that is fed into it.


Thanks for reading, if you have any questions, consider leaving a comment. See you in my next article.


Related articles to check.

  1. Pulverized Coal Firing: Unit or Direct System, Components, Working Principle & Advantages
  2. Advantages Of Cleaning Coal (Dewatering)
  3. 4 Advantages Of Quenching The Ash Before Handling
  4. Requirement That Pulverized Mill Should Satisfy
  5. Conditions For Proper Burning (Combustion) Of Fuel

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