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15m is quite normal outdoors. You should install plenty of fire fighting equipment because coal is prone to spontaneous combustion depending on the time in store and the inherent volatiles. Air exclusion is a normal prerequisite if there will be a long period in store. Use compaction rollers.

In case of fire, some folk suggest spreading the coal over an open vacant area and spraying with water. Dismiss such a practice. How does the burning coal get to the vacant site? How can it be spread?

At the other extreme there was a practice of poking scaffold pipes into the pile in the hope of observing any fire within the pile. I never saw any smoke but I did see the failure of the bucket wheel reclaimer to pass scaffolding. Nobody would agree with me that the pipes represented out-of-spec coal.

There is ample literature explaining the precautions for coal storage within these forums and beyond.

These forums have mention of a scurrilous rumour that Indian coal stockpiles are limited to 10m or below, and that is outdoors. So you need to ascertain the viability of 15m high coal stockpiles. ■

Originally Posted by Shakee

Dear Experts,

In a power station in India, We want to build a stockpile for Indian Coal / Indonesian Coal of (-)50mm size with the help of stacker in a closed storage shed. Due to space restriction height of 15 m becomes a necessity. Can anybody share their experience with 15 m or higher stockpile. If this can be done, what precautions should be taken?

Regards,

Shakee

Dear Mr. Shakee,

At Indonesia 15m stock pile height is quite common. Hope you aware the Indonesian coal's calorific value is also bit higher side than Indian coal. But those are mostly open yards near to jetties for buffer stacking. Since your case is closed yard inside a plant, you have to be very conscious on safety concern like fire fighting, human movements, etc.

Thanks & Regards

Karthik ■

Originally Posted by conveyorkarthik

Dear Mr. Shakee,

At Indonesia 15m stock pile height is quite common. Hope you aware the Indonesian coal's calorific value is also bit higher side than Indian coal. But those are mostly open yards near to jetties for buffer stacking. Since your case is closed yard inside a plant, you have to be very conscious on safety concern like fire fighting, human movements, etc.

Thanks & Regards

Karthik

Dear Mr.Shakee,

In India,15mtrs height stock pile is common.But Loss of coal due to spontaneous combustion is also very high.

I have seen coal stock fire in lesser height also.

Following precaution can minimize the fire incidence.

1.Evacuation on the basis of first come first serve basis.

2.At any rate do not allow the stock to remain more than 30 days.Re-circulation in lieu of evacuation can be tried.

3.Sprinkle water adequately to keep the stock cool. Some projects aim at 15% moisture content to eliminate fire incidence.

4.Compressing the stock by running bull dozer over the coal stock to free entrapped air,which causes fire is also resorted to.

Rgds,

Narayanan Nalinakshan. ■

Hello,

Coal stockpile can have spontaneous (self ignited) fire in certain situation which depends upon coal chemical characteristics, ambient temperature, moisture, air quantity within stockpile , stagnancy of stockpile etc. as said by mining authorities, plant owners, reputed CHP makers and electricity / coal authorities (statutory bodies). Coal stockpile height influences (promotes / demotes) some of the aforesaid fire causing factors.

As for India and Indian black coal, the consensus is to have stockpile height upto 10 m as can be seen from hundreds of power stations owned by state electricity boards and national power corporations, and so on. This is on the consideration that fire risk will be reasonable (of acceptable level) for 10 m high stockpile, for the situation ‘coal as being handled and stored etc. in such power stations’. Such broad consensus helps speedy decision for construction of new plants, plant insurance cost and so on. The reliability of power supply system is matter of public concern, and therefore government statutory body puts forward certain guide lines. I think practice and procedure prevailing in India will have relevance to British practice.

10 m height as above is not magic boundary. 2 decades ago I saw spontaneous fire at Nashik power station, even though its height was 10 m ! So height issue is to be understood with respect to risk factor. I came across only one coal handling plant in India at Farakka, where they kept the stockpile height less than 10 m, due to particular type of Indian coal. I think they opted for side scraper reclaimers (instead of bucket wheel reclaimer) to enable reclaiming of coal on both the sides of coal zone under spontaneous fire. Side scraper can isolate the fuming zone, form rest of the stockpile.

Regarding stockpile height for Indonesian coal, they must be handling coal at hundreds of mines and power stations in Indonesia. They must also be having specific method, rules and experience, after taking into consideration worldwide views at that time. So refer organizations / institutes / statutory body in Indonesia to know about the stockpile height they consider, and follow it.

If the coal stockpile owner himself is using the power produced from the coal; and nobody else is concerned; then it is up to him whether to have 10 m height or 14 m height, etc.

The short duration stockpile height can be safely more. Coal arriving in large ships may have storage depth more than 10 m, but it does not catch fire.

Following are the options for you in this matter:

a) You have some information about the stockpile height in India. You may find the information about the stockpile height they adopt in Indonesia. Use the stockpile height whichever is less, and have the project.

b) Select the height as per your choice and be responsible for the decision, while taking into consideration the plant insurance cost, etc.

As I know there are stringent rules (as good as law) about handling of coal in underground mines. Yours is a surface installation for which there could be only guidelines. So it is up to you to decide. There is no reason to be in favour or against particular height, it is only compliance to the prevailing system, expected safety and rules.

Regards,

Ishwar G. Mulani

Author of Book : Engineering Science And Application Design For Belt Conveyors (new print November, 2012)

Author of Book : Belt Feeder Design And Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Pune, India.

Tel.: 0091 (0)20 25871916

Email: conveyor.ishwar.mulani@gmail.com

Website: www.conveyor.ishwarmulani.com ■

Originally Posted by Shakee

Dear Experts,

In a power station in India, We want to build a stockpile for Indian Coal / Indonesian Coal of (-)50mm size with the help of stacker in a closed storage shed. Due to space restriction height of 15 m becomes a necessity. Can anybody share their experience with 15 m or higher stockpile. If this can be done, what precautions should be taken?

Regards,

Shakee

Dear Mr. Shakee,

In Vizag steel there is coal pile of height 15M. Ignition is there, but they manage by compacting with Bull dozer.

Coal India recommend only 2.5M. But even with 2.5m height I have seen fire.

I am working in Jindal Steel where I am making pile for coal about 25M height. In China 6 nos installation are there, where coal is stacked at about 27M height.

So 15 M pile height of coal can be done.

Regards.

A.Banerjee ■

Mr. Shakee,

Have you decided on your pile height and what was it?

2.5 metres is quite low so where have you been stacking the coal meantime? ■

Dear Mr. Shakee,

Spontaneous combustion of coal is more in the open stockpile due to the presence of oxygen. Since you are planning for a closed coal stockpile, this problem would be greatly reduced. Many plants have closed storage sheds with pile height of more than 25 m. You may contact the vendors supplying the dome storage shed for further details. ■