2 replies to this topic

[Olaniyi]

Afternoon fellow Che-Resourcers,

I am currently trying to evaluate the possibility of loading 2 different products using the same rail transfer system. The two products are condensate and methanol. They will be produced separately, and stored in (different) tanks adjacent to the rail car tracks. The condensate is produced on site for rail car export, while the methanol will be imported by sea, transferred to a storage tank and then moved along via rail cars as well.

 

Current situation:

Currently the rail system is designed and used only for condensate export. There are 2 condensate tanks, which connect to the railcar loading system.

 

Future (Desired) Situation:

In the future, it is desired to be able to export both condensate and methanol from this rail track. The target is to modify the existing system as little as possible. The current rail tracks are underutilised so capacity-wise there is no need to expand the tracks to accomodate additional cars for methanol export. Also, one tanks is adequate for condensate storage due to significantly reduced production and export, so the second tank is "redundant", and has been for  while.

What I would ideally like to be able to do is:

• Convert one existing condensate tank for methanol storage (a tank expert is helping to look at this, and says that it should be possible).
• Modify the system as required (Add new pumps, loading lines, vapour recovery systems for the methanol tank)
• Load both condensate and methanol from the same rail systems

My questions:

• Is this a common practice i.e. exporting multiple products from the same rail system? I can't seem to find many references online.
• Can I use the same loading arms to the rail car for both products (i.e connect and disconnect loading arms depending on if it is condensate or methanol being loaded?
• I realise I need separate vapour return units from the rail cars to the different tanks. Does this mean I definitely need different vapour return headers ( I assume yes?)

 

I guess ultimately I am looking for good references on rail car export systems and/or manuals that can give me an understanding of how a multiple product export system might work.

 

Apologies for the long email. Many thanks in advance for any help. I can provide more information if required.

 

Cheers, and many thanks!

Ogeds

Edited by ogeds, 03 June 2013 - 09:47 AM.

[Art Montemayor]

Ogeds:

 

If it were me, I would be most concerned with the following before using the same equipment and piping for different fluids:

• I don't know what you mean by "condensate".  The word is a general term unless specifically identified.  Do you mean a hydrocarbon condensate (mostly pentanes, hexanes, & nonanes)?  In any event, what are the contamination issues with either the condensate or the methanol?  Can either (for sales purposes) tolerate being contaminated one by the other?
• Can either (for safety purposes) tolerate being contaminated one by the other?
• Can either attack the fittings' gaskets or seals used in the common installation?
• Can your safety relief devices handle both fluids safely and operationally?
• The above concerns apply to the storage tanks and rail cars as well.

Normally, I would expect that the two fluids are not compatible from a sales or a safety point of view.

[Olaniyi]

Thanks Art for your great insight as always.

Indeed I have considered a few of those things - mainly material of construction, safety devices, and also instrumentation (level guages and safeguarding etc which may be calibrated to different densities etc). The reason I asked the question(s), before going further into it - was to see if this is something that is actually done in the industry - if it is then I have a bit more confidence in trying to see what i can do to design a system that will work safely. If it is not, or I can find guidelines that discourage it - then maybe thats my answer as well and I have to think of other solutions.

 

A bit of history that I left out - in the past there indeed use to be methanol exporting down the same rail tracks further down the line, using different rail tracks but rail cars from (what seems to be, from what I can see so far) same type, capacity with similar instrumentation.. this was since demolished for a new project..

 

So in summary, my question is mainly to look for references and see that this is being done before I delve into trying to do a design

Thanks.

Ogeds

 

PS Indeed condensate is C5(pentane)+