The Waigaoqiao closed cooling water heat exchanger is designed, manufactured and accepted in accordance with the "Boiler and Pressure Vessel Specification" and HEI Power Plant Heat Exchanger Standards.

Usually, the shell side of the tube is a single process or the tube side is a double process, and the shell side is a single process structure of the heat exchanger is more common. According to Siemens requirements, the tube side and shell side of the closed cooling water heat exchanger of Waigaoqiao Power Plant are both double-flow. Generally, increasing the tube arrangement can increase the heat exchange area, but the flow rate of the medium in the tube bundle decreases with the increase of the heat transfer tubes, resulting in a decrease in the heat transfer coefficient of the fluid. In order to ensure that the fluid maintains a large flow rate in the heat transfer tube, the tube side adopts the characteristics of double-flow 3 water chamber. The front and rear water chambers of the closed cooling water heat exchanger of Waigaoqiao Power Plant are of the detachable structure and are equipped with lifting lugs. The top of the second water chamber is a head, and three manholes are arranged on the head for maintenance. Since the heat exchanger tube side is a double flow, a partition plate is placed in the front water chamber to serve as a shunt, and the material used for the partition plate must be the same as the material of the water chamber. According to Siemens requirements, a rubber ball cleaning device is installed on the water chamber side of the closed cooling water heat exchanger, the purpose of which is to improve the heat transfer effect of the heat exchanger by cleaning the dirt in the heat transfer tube. In order to ensure the smooth flow of the rubber ball during cleaning, eliminate dead corners, and also prevent the rubber ball from flowing out of the drain. Therefore, guide plates must be set inside the front and rear water chambers. In order to facilitate disassembly, the guide plates are connected with the support by bolts and nuts. The water quality used in the closed cooling water heat exchanger of Waigaoqiao Power Plant: the shell side is closed circulating cooling water, the tube side is auxiliary water (brackish water), and the water quality of the tube side is poor. In order to prevent the corrosion of brackish water, the method of lining rubber is often used in the past. However, due to external requirements, the inner wall of the water chamber is coated with epoxy resin (except for the flange sealing surface). The reason is that if the flange sealing surface is also coated with epoxy resin, it will often be damaged due to improper operation during installation or maintenance, which will affect the sealing effect of the flange and cause leakage.

At the same time, the flange sealing surface is a part of the water chamber, and its anti-corrosion problem is also very important. Therefore, it is considered in the design that all carbon steel flange sealing surfaces in the water chamber are lined with a layer of about 5 bidirectional stainless steel plates. However, when the lining plate is welded with the sealing surface, deformation is easy to occur, and a gap may also occur between the flange sealing surface and the stainless steel plate. A slight leakage will also cause corrosion. For the above reasons, the method of welding bidirectional stainless steel welding materials on the flange sealing surface is finally adopted to achieve the effect of corrosion resistance to brackish water.

The connection between the tube plate and the shell The closed cooling water heat exchanger of the outer high bridge power plant is a fixed tube plate structure, the tube plate and the shell are welded together, and the two tube plates can double as flanges, and the connection form with the water chamber flange is bolt connection.