Aspen distillation column pressure
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A three-column parallel process was simulated; the overhead and bottom products from the first distillation column both flow into the next column. The key point is that the first column is a vacuum column with a pressure of 30–40 kPa, while the latter two columns are at atmospheric pressure. How should this be handled? Add a pump? How to add? Thank you!
Your question is about how to increase the pressure to proceed to the next stage, and your approach is correct—using a pump to apply pressure. For the specific operations, I recommend using HYSYS for simulation. After adding the pump module, use the stream from the vacuum distillation column as the input stream for the pump, and define the output stream as the name of the stream from the atmospheric pressure column, such as FEED 2. In the pump’s WORKSHEET, set the pressure for FEED 2 to 0.1 Mpa, and this will meet the requirements of the atmospheric pressure column!
Thank you for sharing!! 3Q
Reply to 1# sundancekid: The vacuum tower is connected to the atmospheric pressure tower; this configuration for distillation is something I’ve heard of for the first time. Usually, distillation is carried out either in a pressurized or atmospheric pressure tower, and only when distillation cannot be achieved in those conditions is a vacuum tower used for the purpose. It is recommended to review the process again first； Compressors are used for gas-phase pressurization, while pumps are used for liquid-phase pressurization; this is the standard approach for pressurization ； The setting pressure of 0.1 MPa mentioned on the 2nd floor is clearly highly theoretical and lacks practical experience. In addition to considering the pressure of the next device, the pressure drop caused by pipeline friction losses and other factors must also be taken into account when setting the pump outlet pressure as appropriate.
So, if the first reactor is at 20 bar and the subsequent distillation columns are set at 2 bar, how can pressure reduction be achieved?
Add a VALVE at the desired outlet; in engineering practice, this is usually a pressure reducing valve or an orifice plate