3 replies to this topic

[Sheffieldme]

hello all,

i am currently designing a flash drum to separate liquid ammonia from vapour. i have done the sizing for the flash drum, however, i am having trouble when doing the mechanical design since i am not sure of the operating temperature and pressure of the vessel.

the feed is at -54 celsius and 224 bar, the same goes for the liquid ammonia separated and the gases going to recycle and purge streams. hope there can be some help to enlighten me.

thank you.

[wojtar]

Could you kindly attach some process sketch.

You said that your feed is at -54C and 224 bar (the same for gas and liquid outlet).

How is it possible? At such conditions ammonia is subcooled liquid. Even expanding to atmospheric pressure it is -48C subcooled liquid.

 

Please clarify: are you talking about design parameters or operating parameters?

[yakooworld]

hello....

u must have a presure drop be4 flash drum by a lic valve which controlled in level of ammonia seperator pressure must be 26 bar in flash drum

Edited by yakooworld, 01 February 2013 - 08:12 AM.

[Art Montemayor]

You fail to communicate in an accurate, detailed, and specific manner.  Your query can't be answered because it lacks necessary basic data:

1. Are you adiabatically flashing a stream of liquid ammonia into a flash drum?  If so, what is the temperature, pressure, and flow rate of the ammonia before the expansion valve?  What is the pressure you are maintaining in the flash drum?
2. Submit a detailed sketch of the operation in an Excel spreadsheet.

If you do the above, we can resolve your query quickly, efficiently, and accurately.