Tubular heat exchanger (tubular exchanger) is currently the most widely used heat exchanger in chemical and alcohol production. It is mainly composed of a shell, a tube sheet, a heat exchange tube, a head, a baffle, etc.
Material: stainless steel 304 , 316L, two-way steel 2205, titanium, Hastelloy etc
Operating temperature: -196°C-500°C;
Design pressure: -0.1MPa-1.0MPa;
Applicable fluids: steam, circulating water, frozen brine, glacial refrigerant, glycol ,oil ,etc
In the shell and tube heat exchanger, due to the different temperatures of the fluid inside and outside the tube, the temperatures of the shell and the tube bundle of the heat exchanger are also different. If there is a large difference between the two temperatures, great thermal stress will be generated in the heat exchanger, causing the tubes to bend, break, or pull off the tube sheet. Therefore, when the temperature difference between the tube bundle and the shell exceeds 50°C, appropriate compensation measures must be taken to eliminate or reduce thermal stress. Depending on the compensation measures adopted, shell and tube heat exchangers can be divided into the following main types:
1.Fixed tube plate heat exchanger The tube plates at both ends of the tube bundle of the fixed tube plate heat exchanger are integrated with the shell. The structure is simple, but it is only suitable for heat exchange operations when the temperature difference between hot and cold fluids is not large, and the shell side does not require mechanical cleaning. When the temperature difference is slightly larger and the shell pressure is not too high, an elastic compensation ring can be installed on the shell to reduce thermal stress.
2.Floating heat exchanger The tube plate at one end of the tube bundle of the floating head heat exchanger can float freely, completely eliminating thermal stress; and the entire tube bundle can be extracted from the shell, making it easy for mechanical cleaning and maintenance. Floating head heat exchangers are widely used, but their structures are complex and their costs are high.
3.U-shaped tube heat exchanger Each heat exchange tube is bent into a U shape, and its two ends are fixed on the same tube plate in the upper and lower areas. It is divided into two chambers, the inlet and outlet, with the help of partitions in the tube box. This type of heat exchanger completely eliminates thermal stress and has a simpler structure than the floating head type, but the tube side is not easy to clean.
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