TURBOEXPANDERS 1

[tomato5]

Personally, I have not had an opportunity to work on an expander, some other turbomachinery yes so some experienced information would be very welcome

1. I understand that there are both gas and liquid expanders in fact (gas + liquid) also is this correct?
2. How would you determine Expander HP for each of these. I guess the liquid one might be easy, but the other two more involved. Would you have an article, or reference to a book with some examples of expander calculation?
3. In LNG service, are both used?
4. What process in hydrocarbon processing, other than LNG, would use expanders
5. If we refer to a gas expander as expander, is there a better term to describe a liquid expander?

Thanks a lot!

 

[GHartmann]

Here is a simplified version:

http://en.wikipedia.org/wiki/Turboexpander

Most compression handbooks should have a section on expansion turbines

In the petrochem industry, hot gas expanders are used in FCC units

In the fertilizer industry they are utilized in nitric acid plants

And of course on a small scale they are utilized with automobile engines

I will have to revert to other posters regarding liquid expanders (I can only think of hydroelectric plants)

 

[dcasto]

1 yes

2 assume the isentropic eff to start with at 75% liquid expanders are not that common when 2 phase occurs. Ebara cryodynamics have some interesting expanders, especially in lng

3 yes gas expanders on the refrigeration cycles liquid on subcooled luquid lng

4 expanders are the work horse in ngl recovery, removing ethane and heaviers fronm natural gas. Lng refrigeration cycles use expanders.

5 i always call a liquid expander as a let down turbine the first ones i used were on rich amine. We would use it as the level control valve on the absorber. It was direct coupked to the main amine pump. The pump would handle about 1/3 of the flow. This meas the turbine or expander was under 30% efficient including the pump efficency.