Resin Freezing in railcar Issue

[sachigh]

We will soon be getting Keldax(type of filled EVA) in railcars. The problem is they will be moving from the warm climate in Tennessee upto the cold winter months in Michigan.The material also absorbs some moisture. We are planning to use the railcar as our storage.We plan to empty one railcar in two to three weeks time. I want to know if anybody has had the freezing issues with the railcar and how you addessed it.

We do not have any garage to park the railcar in a warm area. Some solutions are the vibrators on the railcar and the blowing warm air through the car. But blowing warm air will cause more condensation if we do not use the railcars soon enough.

Your inputs would be very helpful. Thank you.

 

[Demon3]

First let me say that I have no experience with the exact issue you described. However, having said that, I do not imagine any problem. Usually such resins stick together when too warm but I do not see any problem with them being too cold. What do you mean by "freezing issues"? I don't think the pellets will stick together and if they adsorb some moisture then standard pre-drying should work.

 

[sachigh]

When the material is loaded to railcars in Tennesse, its warm , maybe room temperature air. When it travels to Michigan the weather changes, hence the dew point temperature decreases and condensation takes place. This condensation causes freezing. It's not exactly plastic sticking together but the condensation causing the freezing. It is not a major freezing issue like a block of ice either.

If we have to blow warm air into the railcar then we have to do that continuosly till we empty the railcar or else it will cause more condensation. I'm not sure of the cost of blowing warm air 24/7 for 2-3 weeks yet during the winter months. The reason we went to railcars was that the cost of resin is cheaper. Looking for a cheaper and workable alternative.

 

[btrueblood]

Purge with dry nitrogen, then seal?

 

[sachigh]

How expensive will that be? And also when we need to unload the railcar we will still need to vent the railcar.

 

[btrueblood]

How expensive will that be? Much less than a continuous flow of heated air. Your concern is that the heated air, if flow is stopped, will cool and you'll still get condensation (I would agree). You need to displace the moist air with something that is dry. You could consider de-humidifying your air, but if you "do the math" you'll find that using bottled N2 is cheaper. Why? Liquid and bottled N2 are "by-products" of medical oxygen production, thus their production is subsidized (by your health insurance).

 

[sachigh]

Purging with nitrogen at our plant, I wonder how beneficial it would be considering it would have already frozen when it reaches from Tennessee to Michigan weather. Purging with nitrogen at Tennessee would help but the railcars are not air-tight sealed.

 

[btrueblood]

Sorry, we still aren't communicating. Yes, you need to blow warm air into the car, to melt any ice and drive off as much water as possible. But, if you leave the moist, humidified warm air in the car, and it subsequently cools, the moisture in that air, plus air drawn into the car as it cools, will again condense. The solution is, after warming/drying, to displace all the air in the car with dry N2. Ideally, pull a vacuum on the car then backfill with N2; if done several times your dewpoint falls rapidly. But, I don't think you want to pull much of a vacuum on a rail car, I don't think they are rated for it. Good luck.