For a specific project, our client needed to replace an existing heat exchanger. The issue with the current shell & tube unit is that the process flow causes lactide buildup within the shell, particularly on the impingement plate and the bottom of the shell. The request was whether Robox could create a design incorporating features to melt off the lactide without having to remove the bundle.
The underside of the shell is equipped with an external heating jacket. This is fitted with nozzles connected to a hot water circuit to heat the bottom of the shell and melt the accumulated lactide on the inside of the shell.
In the previous heat exchanger, lactide buildup also occurred on the impingement plate. Since the risk of liquid particles at the inlet is very low, the decision was made to omit the impingement plate. However, to protect the tubes from impingement damage, heavy-wall tubes were selected. If lactide builds up on the tubes, it is melted off by circulating hot water through the bundle.
This concerns a Shell & Tube heat exchanger. The shell side cross (X) flow ensures a very low pressure drop of 0.009 kPa at a vacuum inlet pressure of 0.018 kPa (abs). Type BXU 406/3650, constructed in SS316 according to PED cat.IV/mod.H1 and ASME VIII div. 1.