Greetings Albert, from the soon to be frozen "Eastern Wilderness" @1140 feet above sea level.

Regarding your belt it has a fire resistance rating for a certain amount of time and after that it will burn.

The only sure way to stop the fires completely is to use a steel plow conveyor to move the coal along a steel trough to the delivery point.

The only sure way to eliminate any possibility of a fire resulting from spontaneos combustion of your coal fuels is to empty the belt continously and leave it empty during shut down times other wise you are always going to have this problem.

This is the fastest and easiest solution as you are removing the fuel from the belt

Also make sure your scrapers are working properly if you have them installed at the head pulleys and and the v plows at the tail pulleys of your conveyor system.

You can always spray water on the coal at transfer points or along the belt but to do any good you would really have to soak it and it just

makes more of a mess. Removing water from soft coal to burn it takes a lot of heat energy as well.

A fire has three componenents.

Fuel- which in your case is soft coal.

Heat-which is the result of the deterioration of the soft coal you are using due to the environment that the coal is stored in.

Atmosperic oxygen- which increases the combustion of the fuel.

If you remove any part of the fire triangle which consists of fuel, heat and oxygen the fire will go out.

lzaharis ■

the other component our colleage forgot is time thermal resistance and conductivity .

fire resiutant belts are normally not very resistan to high temperature and tend to melt , we tried using a layer of lime as insulator when rteclaiming material from a burning sponge iron storage , it worked , also we never stopped the conveyors and lkimited the residebnce time by limiting the lenght of the belt. Finally we used infrared sensors and seppartion stations to remove hot product from the belts .

there is an old patent of mine , now public domain on this regards,Verdugo et all. there is also a paralell patent from Larry Coccia covering other aspects of the same concept.

If you wish i will be able to take a look and see if we can help you. Just drop me a line .

marco ■

You have a twofold problem, on one hand you have to make sure that if the coal spontaneously combusts the belt itself does not catch fire and therefore create a hell of a lot more damage and on the second instance, when the belt is stationary for a period with coal on it, spon com causes the belt to be damaged. As I see it the greater risk is if the belt catches fire especially when it is operating so I do not believe you have a choice but to use the very best fire resistant belt and that means a neoprene based compound to British or Australian Standards. This type of belt is completely self extinguishing.

Having done this you have an issue. the very best heat resistant belts made out of EPDM are flammable. The heat resistance of neoprene (chloroprene) is quite moderate. It is also probable that the heat generated from spon com of coal will be well in excess of what any heat resistant belt can withstand over the sort of time frame you are describing anyway so trying to specify a belt solution is in my opinion not an option. Water sprays from my experience add to the liklihood of spon com so I do not believe it is an option. Therefore it is a management issue and that is you must empty the belts of this type of coal (that is coal that will spon com) regardless and this means having bins or something similar that allows the material to be run off if the process does not allow other alternatives

Regards

Col Benjamin

Gulf Conveyor Systems P/L

colin.benjamin@gcsm.com.au ■

I agree .

Check with Pt Kracatoa Steel in Cota Baja Indonesia they had a similar problem with sponge iron. Their solution might help ■

The steel industry solution for their coke belts usually includes water quenching and this together with a good EPDM compound gives the best result. With coal that can spontaneously combust, water usually adds to the liklihood of spon com in realitively modest quantities and full quenching is not an option when such coal is used as a fuel source so there is a limit to the volume of water that you want in the coal. This is why you have to look to a self extinguishing belt first and foremost because if the belt catches fire you have real hassles. It is why the solution has to be different.

Col Benjamin

Gulf Conveyor Systems Pty Ltd ■

Some people had gone the same way with sponge iron , and hot iron ore , hot sponge also ignites lets say the fines can sponcom at ambient temp , using water might eliminate the fire (flames), but will leave everything the same , spncombst can start any moment , it also generates hidrogen , that can cause an explosion if confined in bins or storage (ships) it also can create problems in the electric furnace is somehow water can pool under the liquid metal or slag , the use of flame retardant or self extinguishing (neoprene) conveyors is wide spread , I would not use water but to control a fire, in any case the part that is damaging your conveyor sits at the bottom and the water impinges on the top, if the conveyor is not flat the water can run on the conveyou without wetting the hot material, also some materials are not fond of water , some reallu act nasty when hot in contact with water.

As is , limiting the residence time in the conveyor with Multiple transfers , More dust ,

Or using an insulating Heat resisting layer of stabilised silicon, or a layer or material )lime has been reccomended and used in some places succesfully .

You have to do inteligent choices based on your particular instalation , try to keep your belts running and provide if you can a purging point for each conveyor .

See is a local supplier can build a sandwish conveyoy with silicoin as upper layer and neoprene in the bottom, you can dope the silicon with taconite if necesary. try in very small scale and test you might be surprised on hopw easy it is , do not allow experts to scare you .

Marco

RegardsçMarco ■