Heat exchanger is an unit equipment widly used in chemical, petroleum, energy and other industries. According to statistics, he heat exchanger investment accounts for about 30% of the total investment of the equipment in the modern chemical industry, 40% of all process equipment in refineries. Desalination process devices are almost all of the heat exchanger composition. Investigation of foreign heat exchanger market shows that, Although the competitiveness of various plate heat exchangers is on the rise, the shell and tube heat exchanger still dominates about 64%. Development of new heat exchange element and high efficiency heat exchanger shows that tube heat exchanger has entered a new period of research. Whether the heat exchanger tubes or the shell-side baffle structure has been greatly changed compared with the traditional shell and tube heat exchanger. Its hydrodynamic performance, heat transfer efficiency, anti-vibration and anti-scaling effects have also made new progress in theoretical research and structural design.
In the shell and tube heat exchanger, single-pass heat exchanger is the most simple one. If you need to increase the heat transfer surface, generally you can increase the number of tubes. After the increase in the number of tube bundle, it can be split to prevent the reduction of tube flow rate and heat transfer coefficient caused by the increase in the number of tubes. View from the manufacturing, installation and operation, generally use even number of pipe and the process should not be too much.
E-type is the most common type. Shell side is one-way, the tube can be one-way process or also can be more. F-type is two shell side heat exchanger. In the shell is installed in a parallel to the longitudinal axis of the tube wall. G-type is also two shell side heat exchanger. The removal of the longitudinal bulkhead from one section of the tube sheet diverts the shell fluid. H-type is similar to G-type, but the import and export of pipe and longitudinal baffle are doubled.
Tube bundle arrangement
Tube bundle arrangement on the tube plate has four most common types: Regular Triangle, Corner Triangle, Square, and Corner Squares.
Tube plate is one of the important components of the heat exchanger. It is used to arrange the heat pipe and separate the tube pass and shell side space. Thin tube sheet has the advantage of saving material and is suitable for medium and low pressure heat exchanger. Oval tube plate and the heat exchanger shell are welded together, the stress conditions are good,so it is suitable for high pressure and large diameter heat exchanger.
Baffle plates and Baffle rod
Baffle plate helps to increase the flow rate of the shell side, enhance the turbulence and improve the heat transfer. It plays the role of supporting tube bundle in the horizontal heat exchanger. Common baffle plates are single bow, double bow, triple bow and so on. Baffle rod is a new type structure of tube supporting. Its advantage is that in the case of the same heat transfer, its pressure drop is more than 50% lower than that of bow baffle heat exchangers. It has no dead zone for heat transfer. The fouling rate is slow so that it can prevent the lateral flow induced vibration.