This is a replacement project. The problem with the previous Shell & Tube heat exchanger was lactide accumulation inside the shell, especially on the impingement plate and at the bottom of the shell. Our challenge was to enable lactide melt-off in-place, and without removal of the bundle.
Our solution was to integrate a hot water heat tracing at the bottom of the shell. The heat tracing nozzles are connected to a hot water circuit so that any lactide accumulation inside the shell is melted-off.
Because the probability of liquids at the inlet was very low, we decided to omit the impingement plate. However, to accommodate for liquids, we increased the wall thickness of the tubes to increase their resistance against impingement. When lactide would accumulate on the tubes, hot water is run through the tubes to melt-off the lactide.
This is a Shell & Tube heat exchanger. The shell side cross (X) flow features a very low pressure drop of 0.009 kPa at a vacuum inlet pressure of 0.018 kPa (abs). Type BXU 406/3650 in SS316 and according to PED cat.IV/mod.H1 and ASME VIII div. 1