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suresh77babu
20-01-2013, 04:48 PM
Dear All,
please help me to understand the following issue, in ammonia plant the ammonia vapors are being condensed by refrigeration compressor.
we have ammonia refrigeration compressor capacity of 200 tons/hr. compressor final discharge pressure is 18kg/cm2 and temperature 130 deg c. we are using sea water coolers for ammonia vapors condensing.

My question is
what is the critical pressure and temperature of ammonia.
will ammonia will condense above critical temperature and bleow critical pressure.
will ammonai will condense below critical temperatue and above critical pressure.
will ammonia will condense at equal to crtical pressure and temperature.

if my compresssor discharge pressure is increased to 25 kg/cm2 will we can condense the vapors or not. at which pressure and temperature ammonia will not condense.

please help me the above questions to understand easily.
if any mistake in the above qustion please let me know.
Thanks and Regards,
Suresh

sandybapat
21-01-2013, 05:07 AM
critical pressure of Ammonia is 112.8 Bar. You can very well condense Ammonia at 25 kg/cm2g. Corresponding condensing temperature (Saturation temperature) will be around 60 deg C. Critical temperature for Ammonia is 132.4 deg C (saturation temperature)

suresh77babu
24-01-2013, 01:58 AM
Thank you dear sandy, please help to understand the above concept. i know above critical temperaure any gas will not condense but can be made solid. but in case of ammonia, upto which pressure and temperaure we can go for compression and condensing. i feel my exhcanger size will increased to have condensing and need further pressure drop or qunching required at discharge line to condense. i want to know whether we can condense ammonia vapor if we taken the upto critical pressure or temperature. below critical temperature of ammonia will it condense or not.

Thanks and regards,
suresh

martinw58
24-01-2013, 07:49 AM
you need to check the max pressure the componants of your system can safely work at and the pressures you need to run at for the required temperature and duty of your system. you need to size your condenser correctly to the duty of your system for the system to run efficiently and at the correct temperature.

pepsiqazi
01-04-2013, 09:40 AM
size your condenser correctly

Magoo
02-04-2013, 01:14 AM
You need to clean the sea water cooled condensers tubes if your discharge pressures are increasing