Protect steel from corrosion and errosion due to coal

[TCPhoenix]

I have a set of I-beams over a hopper that are used to support a hopper train car filled with coal(low sulfur). The car is positioned over the hopper and then dumps the coal over the I-beams and into the hopper.


I am looking to protect steel I-Beams from corrosion and errosion due to coal. Any suggestions on coatings?

 

[gr2vessels]

There is no coating to resist the corrosion / erosion of coal and also be feasible. Thick corrosion allowance for your beams is the best answer. Or armor plates (replaceable) on top of those beams. Alternatively, there are beams made of materials like 12Cr (poor man's stainless steel) capable of extending the life of your beams, but will not be immune to the coal attack.
Hope this helps.
gr2vessels

 

[metengr]

TCPhoenix;

I was trying to follow your post above as to why one would use I-beams in the direct line of sight for the flow of coal into a hopper? Was this some type of modification because of structural concerns? What type of coal unloading facility is this - a car dumper or car bottom unloading facility?

You could try a rubber mastic coating over the I-beam to deflect the coal. Believe it or not, rubber does work in some coal handling facilities.

 

[corrosionman]

TCPhoenix
your problem is easily solved. get some wear resistant alumina tiles and adhesive bond them to the impact surface of the I beams.Tell us where you are and I'll find a supplier inyour area. Cast Basalt tiles will do almost as good but the standard size is 8 x 8 and 8 x 4 and this would mean cutting them to be a neat fit. possibly with alumina you will find something just the right size.
For adhesive, any good two part epoxy will do, but if you have a good Fibreglass company in your area just use a general purpose polyester resin
Regards DW

 

[rmw]

There are erosion resistant coatings that can be applied by metal spray application. Many of these type coatings are used in the type of boilers that the coal is burned in. Ask your boiler guys what they are doing in specific high wear areas.

There are also weld overlay options. I like the basalt mentioned above in particular if you can get the tiles to fit.

rmw

 

[bridgebuster]

Have you considered weathering steel? It was actually developed for construction of coal carrying railroad gondolas.

 

[mshimko]

From a cost effectiveness perspective, I offer the following:
1. I don't see any conventional coating holding up to the physical abrasions;
2. I don't think you'll be able to properly apply any of the many metal-spray coatings, which require extreme cleanliness and QA to work as advertized.
3. If your system is already designed and constructed, then it's too late to redesign or change materials.

This means that you're stuck between a rock and a hard place because "your predicessor" didn't consider corrosion in the design and construction.

 

[eyec]

weld stainless 1/4" plate @ 60 deg then weld to top of I-beam. easier to shed the coal and cheaper than repair/replace I-beams

 

[rmw]

Assuming that the first word in eyec's post might also have been "bend" I agree with his answer. I answered the question in the original post regarding coatings previously and I stick by that answer. The metal coatings I referred to are commonly used in coal, wood fired, and paper chemical recovery boilers which have been in service previously and which are hardly pristine environments for metal spray coating application.

However, for simplicity's sake and just as good and probably every bit as long lasting is the "coating" that eyec suggests.

rmw

 

[gr2vessels]

Dear all,
As usually, the person who posted the question did not bother to check for answers (sacked for posting on eng-tips during hours), therefore the debate is only between ourselves.
However, interesting topic and a good selection of replies.
Lets see, train car filled with coal, some large boulders and some smaller sizes of coal. Large content of water, chlorides, fine abrasive sand, sulphuric components, very aggressive cocktail. The car and the shute are made most likely these days from 3CR12 (Columbus) or 5CR12 (Sandvik), as is the Lurgi coal mill made od carbon steel, but protected internally with armour plates made of 12" thick 3CR12 and the pulverised coal ducts made of 3CR12 plate (the cost is closer to carbon steel than the austenitic stainless steel and the thermal expansion is identical to the carbon steel - unlike the austenitic stainless steel). The only stainless steel plate used was the cover of the start/stop button for conveyor.
The coal tends to penetrate every available space, including the space under the bent stainless steel sheeting on top of the beams, and catch fire when it dries and it feels like burning...Also, where it accumulates, even the dry powder will absorb moisture and corrode the proverbial out of everything. There is no austenitic stainless steel welding to resist coal corrosion. Also, it takes only one heavier boulder to fall on the 1/4" sheeting on top of the beam, to remove it for good, before the welding would cool down.
I would start with bolting 1" thick 3CR12 plates in top of those beams and monitor the material loss;- it should last for 3-5 years 'till reaching down to 1/4" thickness, then replace the top plates for safety reasons.
Howzat for argument?
cheers,
gr2vessels

 

[TCPhoenix]

gr2vessels...i am still here-thanks for the insight on coal sitting in behind the stainless steel deflector sheeting/drying out/then catching on fire...that is a very good reason not to use a method that i was seriously considering.

I don’t like the 1" top plate because that still does not eliminate coal sitting on and being in contact with the bottom flange and web of the i-beam. During the coal dump the hopper is filled to the rim and the beams are covered in coal...once the hopper is emptied coal still sits on the edge of the flange.

What do you think of galvanization?