Brazed plate heat exchanger is a new type of high efficiency heat exchanger made by stacking a series of metal sheets with a certain corrugated shape and brazing. Thin rectangular channels are formed between various plates to exchange heat through the plates. Compared with the conventional shell and tube heat exchanger, its heat transfer coefficient is much higher under the same flow resistance and pump power consumption. A partition wall heat exchanger that uses plates to form the heat transfer surface. This type of heat exchanger has a compact structure and a large heat transfer area per unit volume. The main types of partition wall heat exchangers are as follows.
(1) The spiral plate heat exchanger is made of two parallel metal plates that adhere to a certain distance. The cold and hot fluids flow in the spiral channels on both sides of the metal plate. This heat exchanger has a high heat transfer coefficient, a large average temperature difference, a small flow resistance, and is not easy to scale and difficult to repair. The operating pressure does not exceed 2MPa.
(2) The flat-plate heat exchanger is composed of corrugated thin plates and sealing gaskets of certain shapes alternately superimposed and assembled by frame clamping. The cold and hot fluids flow through the flow channels on both sides of the corrugated plate, and exchange heat through the plates. The corrugated board is generally punched from stainless steel, aluminum, titanium, molybdenum and other thin plates with a thickness of 0.5 to 3 mm. The advantage of the plate heat exchanger is that it has a high heat transfer coefficient and is easy to remove and wash. The operating pressure generally does not exceed 2MPa, and the operating temperature does not exceed 250℃.
(3 plate-fin heat exchange consists of a heat exchange plate bundle closed in a header tank with cold and hot fluid inlet and outlet. The plate bundle is formed by overlapping and brazing the plates and corrugated fins. The fluid flows through both sides of the plate and exchanges heat. The fins increase the heat transfer area, promote the turbulence of the fluid, and enhance the equipment. The plate-fin heat exchanger has a very compact structure, good heat transfer, and can be used under pressure Up to 15MPa. But its manufacturing process is messy, the flow channel is small, and the internal leakage is not easy to repair. Therefore, it is limited to clean non-corrosive fluids, such as heat exchangers for air separation.