I would appreciate some guidance from those with more experience regarding the PCW system in polyolefin extrusion granulation systems!
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The extrusion granulation unit is a very important component of polyolefin projects, and in daily operations, the PCW (pelletizing water) system is also one of the key aspects that require regular maintenance. That’s why I have a few questions I’d like to ask the experts at Haichuan! For flow and temperature control in PCW systems, the common approach is as follows: Wuhan Ethylene uses flow control valves to regulate flow, while heat exchangers are used to control the PCW temperature ； Tianjin Zhongsha: Constant flow at the pump outlet manual valve, programmed control of PCW temperature via heat exchanger zoning ； Huilian Phase II: The manual valve at the pump outlet maintains a constant flow rate; PCW temperature control is achieved by regulating the cooling water flow rate to the heat exchanger. Could an expert help analyze the advantages and disadvantages of these 3 control methods? Personally, I feel that reducing traffic control can lower the likelihood of operational errors, and it seems like PCW traffic doesn’t require frequent adjustment either.
The control accuracy for the particle water temperature does not need to be very high; therefore, the simpler the control, the better
In my personal opinion: 1. The latter two options give up precise control over the flow rate, as the flow rate of granular water has little impact on the granulation system； 2. The PCW temperature plays a crucial role in pellet molding; therefore, temperature control is essential. As for the methods of control, I wonder whether, like what Hui Lian does by controlling the flow rate of cooling water, this could serve as another way to reduce the consumption of cooling water (Relative constant cooling water flow rate)