1 reply to this topic

[mahsaatyabi]

Hello fellow HYSYS users,

 

I am working on a compression package using HYSYS Dynamic. There are a few kettle-type heat exchangers in between compressor stages in which wet CO2 enters the tube and cools down to 125 C. On the shell side (liquid) water enters at 104 C and exits at 115 C steam (vapor). There are two concerns:

 

1) The UA value should be specified in dynamics and it should change over time during transient scenarios (shutdown and start-up). UA is not a constant.

 

2) Water level in the shell also needs to be controlled in order to maintain the outlet tube stream at 125 C. 

 

How can points 1 and 2 be done in HYSYS S&T heat exchanger? I would appreciate your response in detail with a HYSYS example file (if possible).

 

Regards,

Mahsa

[ChEf]

If you are doing a dynamic simulation, you need to start from the equipment mechanical data. For a heat exchanger they are usually available on the mechanical datasheet of the exchanger: surface, overall heat transfer coefficient etc. If you don't have this level of detail, you need to perform a preliminary thermal rating of the exchanger using for example edr. In case the water level can drop below the tube bundle, leaving dry tubes, then your model shall have a spreadsheet to calculate the actual surface below the water level.