cryogenic separation of natural gas

[mehmetakyuz]

We are senior students in METU in Turkey. In our design course, we are trying to develop a cryogenic separation process with pumps, heat exchanger networks and flash separation units. Our feed is wet natural gas with 8 bar and 20 celcius and we'll produce %94-95(wt%) purity of methane. Do you have any information about these units cost, design tips and optimization functions.

Have a nice day....

 

[krecian]

What do you want to do with this feed? What components you want to separate. First decide on the objectives. Here are some steps:
1. Dry the gas - moisture removal using silica gel or mol seives
2. Remove arsenic or mercury, if present
3. Remove acid gases - H2S etc - (Amine treating?)
4. Remove heavy hydro-carbons for dew-point requirements
5. remove c2,C3,C4 before sending the NG to end user, if there is economical benefit of removing them at source.
6. Cool and compress to LNG fo shipping to remote users OR simply compress and send-out through pipelines for users nearby.

After freezing the overall process-flow, identify each equipment- column, flash vessel, HE, pump etc- and cost for each component/system. Include costs for civil work, equipment erection, piping work, instrumentation and control system and electrical components. . . .

Break-down the entire system in to simple components and cost.

Hope this broad view is of some use.

KRECian

 

[mehmetakyuz]

Thanks for your attention,
We have some problem about heat exchenger analysis.
in our design we use 2 phase feed.first we give only gas phase mixer but during process, the feed changes into 2 phase.So we can't perform heat exchanger network. we must use another coefficient rather then cp.How can we solve that problem??
Have a nice day.....