Frozen coal in railcars 4

[agrico]

We are interested in talking to anyone who uses hot water to warm railcar steel so that frozen coal will dump out when the car goes through a rotary dumper (or has an opinion if it will work).

 

[metengr]

We deal with frozen coal in railcars cars some of the time during the winter months in the Midwest. Our railcars are aluminum not steel. I would not recommend using hot water because it could cause handling problems of the coal down the conveyor line in frigid weather, and create a serious mess with the car dumper rotating parts. In addition, you would need an awful lot of hot water considering the amount of coal in a typical railcar. We use heaters, on occasion.

 

[buzzp]

Not sure if this an option or practical for you but smaller coal (3/4" or smaller) is often mixed with oil to provide enough lubrication in the event it freezes to metal. It also helps to start the coal on fire if this is what it is used for. Perhaps an oil mist on the edges will resolve your problem but your boiler may not like it much, dont know.

 

[pmover]

well now...

at the coal-fired plants here in AK, the railcars are brought into an enclosed building and left overnight to warm-up. there are large heaters below grade to allow the warm air to rise and warm the railcars. not necessary to warm the cars/coal that much above freezing. about -20°F this am and suppose to get colder (-40°F) by end of week. of course, this does depend upon the amount of coal burned daily - your situation may warrant a large bldg.

happy holidays!
good luck!
-pmover

 

[athomas236]

In Poland, where it also gets very cold, I understand the mines spray the coal with some form of anti-freeze.

athomas236

 

[Muggle]

You might consider the coal cars having a thermal blanket along the inside wall - the blanket would be like solar water heater - allowing hot water to rotate inside the jacket - jackets could be steel, or rigid plastic (so caol weight does not crimp the flow channels.

The water could be heated using small freon compressor - which could sit on/in another car, or outside on the top of the coal carrier.

Just a thought...

 

[metengr]

Interesting suggestion Muggel. However, in our business the cost of hauling coal is 80% of the total fuel cost. This means that you must maximize the weight of coal in each car to take advantage of rail transportation charges.

Railcars need to be lightweight and durable for handling the tonnages of coal that are delivered to Power Stations. For the most part, car dumpers do a reasonably good job of handling coal that gets wet and freezes during transportation.

 

[EdStainless]

I have seen a system in a mine (not coal) where the outside of the cars was sprayed with very hot water. They just wanted to melt the ice holding the ore into the cars, then it would dump.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[agrico]

To: EdStainless

I would really like to talk to the company you referred to that currently uses hot water on their ore rail cars - can you give me a name?

Thanks,
Agrico

 

[MJCronin]

agri,

Some utility companies use "freeze conditioning agents" sprayed on the coal during freezing conditions, an effective but expensive method...

http://www.benetechusa.com/BenetechV3/Pdfs_download images/FCABulletin.pdf

Some people use car vibrators...

http://www.navco.org/hopper-car-unload-vibrators/railcar2.html

Other organizations have tries special coatings on railcars..

An excellent discussion of various methodologies is contained in:

http://www.hnd.usace.army.mil/techinfo/UFC/UFC3-430-02FA/TM581015/chap5.pdf

Gimme a star

My opinion only

MJC

 

[transloading]

Of course you could use Transloading Services to unload frozen coal. This unit is portable and goes on top of the railcars to unload frozen bulk materials.

http://www.transloadingservices.net

http://www.transloading.us

Or you could use CTS Industries to coat the coal with a environmental safe freeze conditioning.

http://www.ctsindustries.us

 

[ChiefMark]

I feel your pain. Several years ago I used a calcium chloride solution sprayed on the top of the coal car. Allow to soak for a couple hours and unload with a car shaker. Even if the solution re-freezes in the car, the strengh of the ice is substantially reduced. The calcium chloride doesn't have the corrosive potential that sodium chloride does. You may want to consider any stainless steel in the boiler (if applicable) for possible chloride stress corrosion. I could probably find some more information on dosage, etc. if you're interested.

 

[pwliquid]

here they have built a sort of surface tunnel structures (long sheds) that are used to park the coal cars inside them. then the cars are heated with steam through a bunch of pipes. the sheds are long enough to fit a whole train.

a few words about the structure: the shed is made out of concrete and so are the steam pipes (U or L-shaped concrete pipes made on spot; check the attached sketches for better understanding). there are 4 pipes, 2 on each side. they preffered two instead of a long one because of the presure needed to inject the steam (longer pipe needs higher pressure). there are also a couple of vents on the top that collect the used steam.

image link:

http://img339.imageshack.us/img339/9977/pwsteamshed1207053ft.jpg

 

[davidbeach]

the sheds are long enough to fit a whole train

In that case, I would guess that this is not a North American installation as the typical unit coal train is in excess of a mile in length. More likely they would work on a smaller cut of cars rather than the whole train.

 

[pwliquid]

David, I guess you're right. "Here" means Romania and I should have said something about the length too. There are two such installations, each one of about 0.2 miles long, but the trains are a lot shorter and the plant is smaller than your average plant.