Cryo system design. 2

[danthemeterman]

I am new to cryogenics. I have been singled out to engineer a system to convert methane gas to liquid. Create storage, and transfer the product to new locations. I have lots of experience in Liquid propane, so the concept of cryogenics is not totally foreign, although condensers are.Any help in finding supplies,support and engineering would be very helpful. I plan on trying to attend the classes in Colorado this year, does anyone have any comments on that ? Thank you in advance.
danthemeterman

 

[dcasto]

the CO2 has to be removed to less than 100 ppm. All the rest of the components are not a problem.

a combination memebrane and amine would most likele be thge best. I'd also look at propylene carbonate and amine

 

[someguy79]

True, the CO2 is probably your biggest problem to deal with. dcasto probably has a better idea of what's economically good on the 50000 gpd scale. Plants I dealt with were much smaller.

The other stuff might not be a problem in liquefaction of LNG. However, in terms of meeting a product specification might make some of these more problematic. For example, you might have high levels of propane with associated gas. It would not cause any real problems in liquefaction, but your end user might not like it.

 

[danthemeterman]

Ok, now I am at the point where I need to start compiling all your great info, and some from other engineers I found to find out if this is feesible(?)I have looked all through this site to find out how to contact people to know avail. I fully expect this post to be rejected, and hopefully when it is they will contact me for further correspondence.
Thank You.

 

[dcasto]

if you go to a big engineering firm, you'll get big in the box thinking. IMHO. your task requires small out of the box thinking.

 

[danthemeterman]

dcasto! I know, so any suggestions ? Thank you ! Sincerely.

 

[iainuts]

I'd agree with dcasto's last comment. Here's a couple out of the box ideas that add on to my previous suggestion of using LIN.
1. If you freeze the CO2 out, you could separate it with a strainer.

2. Putting it through a large vessel where velocity is minimal might allow the frozen CO2 to drop out.

Doing either (or both) of these at an intermediate step of around -80 F means the CO2 will be solidified and the remainder will be gas. The only concern I'd have is that there would probably need to be some way of getting the solidified CO2 to form large 'chunks', large enough to get stuck in a strainer or fall out at low velocity in the tank.

This also adds some cost to the economic analysis I provided earlier of course (May 12 @ 19:11). Take a look at that again and see if the use of LIN is cost effective or not - still curious if the above cost is reasonable for you.

 

[dcasto]

Here is a website that reviews different CO2 removal technologies:

http://www.bre.com/Resources/TechnicalArticles/tabid/96/Default.aspx

Trying to remove CO2 in a solid phase is a patented process by Exxon, the Ryan/Holmes. Noticed I said try.

http://www.patentstorm.us/patents/5335504/description.html

 

[dcasto]

Even with good CO2 removal, some CO2 will build up in the bottom of the LNG stoarge tank and the tank can be warmed up and the CO2 removed periodically. This happens when the CO2 is under .5% in the feed stream. Once you get over .5%, CO2 ice will eventually stop up lines and the system will have to be warmed up (derimed).

 

[someguy79]

I can't comment on how exactly to do the CO2 freezing heat exchanger, (confidentiality issues) but I can say it has been done. Been there, done that myself.

As dcasto alluded, the CO2 will tend to freeze onto stuff rather than drop out as particulate or something.

Freezing isn't my favorite method for CO2 removal. I've also used vacuum pressure swing adsorption. I've considered using amines and a few other methods too, but they weren't cost effective on the scale I was to produce.

You might give a call to my old company (

http://www.prometheus-energy.com/).

I don't know if they still have capacity for any new projects, but this sounds more and more like the kind of thing I used to do.

 

[cryophysics]

Any guies here are in the line of air separation plant