Views:5 Author:Site Editor Publish Time: 2021-04-16 Origin:Site
1. Shell and tube heat exchanger
Shell-and-tube heat exchangers are also called shell-and-tube heat exchangers. It is a partitioned spiral plate heat exchanger with the wall surface of the tube bundle enclosed in the shell as the heat transfer surface. This kind of heat exchanger has a relatively simple structure and reliable operation. It can be made of various structural materials (mainly metal materials) and can be used under high temperature and high pressure. It is currently a widely used type.
2. Fixed tube plate heat exchanger
The fixed tube-sheet heat exchanger is a kind of shell-and-tube heat exchanger. The tube plates at both ends of the fixed tube sheet spiral plate heat exchanger are connected to the shell by welding, and are mainly composed of shell, tube sheet, tube bundle, top cover (head) and other components. The advantages of the fixed tube-sheet heat exchanger are: simple structure, in the same shell diameter, many rows of tubes, few bypasses, each heat exchange tube can be replaced, and the inside of the tube is easy to clean.
The disadvantages of the fixed tube-sheet heat exchanger are: the shell side cannot be mechanically cleaned, it is only suitable for fluid cleaning and not easy to scale, and the temperature difference between the two fluids is not large or the temperature difference is large but the shell side pressure is not high.
3. Floating head heat exchanger
Floating head heat exchanger is a kind of shell-and-tube spiral plate heat exchanger. It has one end of the tube sheet that is not connected to the shell and can float freely along the axial direction. It is also called a floating head. The floating head is composed of a floating tube plate, a hook ring and a floating head end cover, and is detachably connected, and the tube bundle can be drawn out of the shell. ￼The advantage of floating head heat exchanger is: if there is a temperature difference between the heat exchange tube and the shell, that is, when the shell or heat exchange tube expands, there will be no temperature difference stress, and the tube bundle can be drawn out of the shell, which is convenient for the tube and the tube. Clean.
The disadvantages of the floating head heat exchanger are: the structure is more complicated, the amount of materials used is large, and the cost is high. If the sealing between the floating head cover and the floating tube plate is not tight, internal leakage will occur, resulting in the mixing of the two media.
4. U-shaped tube heat exchanger
U-shaped tube heat exchanger is a kind of shell and tube heat exchanger, which is composed of tube sheet, shell, tube bundle and other parts. Each tube of the U-tube spiral plate heat exchanger is bent into a U-shape, and the inlet and outlet are respectively installed on both sides of the same tube plate. The head is divided into two chambers with a partition plate, so that each tube can be used. It is free to expand and contract, and has nothing to do with other tubes and shells.
The advantages of the U-tube heat exchanger are: the tube bundle can float freely without considering the temperature difference stress, and can be used in large temperature differences. It has only one tube plate, fewer flanges, fewer leaks, and simple structure. The U-tube heat exchanger The heater is reliable in operation and low in cost.
The disadvantages of U-tube heat exchangers are: it is difficult to clean the inside of the tube, because the tubes need to have a certain bending radius, the utilization rate of the tube sheet is low, the tube spacing in the inner layer of the tube bundle is large, and the shell side is easy to short circuit. When the flow velocity in the pipe is too high, it will cause serious erosion to the U-shaped elbow section and affect its service life. If the inner pipe is damaged, it cannot be replaced, so the scrap rate is high.
5. spray heat exchanger
The spray heat exchanger is a kind of tube heat exchanger, which is to fix the heat exchange tubes in rows on the steel frame, the hot fluid flows in the tubes, and the cooling water is evenly showered from the spray device above, so it is also called Spray cooler. The advantages of spray heat exchangers are: simple structure, low cost, can reduce the temperature of cooling water, increase the driving force of heat transfer, can withstand high pressure, easy to repair, clean, low water quality requirements. The disadvantage of spray heat exchanger is: uneven cooling water spray will affect the heat transfer effect, and it can only be installed outdoors.
6. double-pipe heat exchanger
The tube-in-tube heat exchanger is a type of tube-type spiral plate heat exchanger. It is a concentric tube tube connected by two standard tubes of different sizes. The outer tube is called the shell side and the inner tube is called the tube side. Two different media can flow in the opposite direction (or the same direction) in the shell side and the tube side to achieve the effect of heat exchange. The advantages of the double-pipe heat exchanger are: simple structure, high pressure resistance, heat transfer area can be increased or decreased as required, and convenient application.
The shortcomings of the double-pipe heat exchanger are: there are many joints between the pipes, which are easy to leak, occupy a large area, and consume a large amount of metal per unit heat transfer surface.
7. Jacketed heat exchanger
Jacketed heat exchanger is a type of plate heat exchanger. It is made by installing a jacket on the outer wall of the container and has a simple structure; but its heating surface is limited by the container wall, and the heat transfer coefficient is not high. In order to improve the heat transfer coefficient and make the liquid in the kettle evenly heated, a stirrer can be installed in the kettle. When cooling water or non-phase change heating agent is passed into the jacket, spiral partitions or other measures to increase turbulence can also be arranged in the jacket to increase the heat supply coefficient on one side of the jacket. In order to supplement the lack of heat transfer surface, a snake tube can also be installed inside the kettle. Jacketed spiral plate heat exchangers are widely used for heating and cooling in the reaction process.
The advantages of jacketed heat exchangers are: simple structure and convenient processing. The disadvantages of jacketed heat exchangers are: small heat transfer area and low heat transfer efficiency.
8. Spiral plate heat exchanger
The spiral plate heat exchanger is a type of plate heat exchanger, which is made of two parallel metal plates rolled into two concentric spiral channels. A partition is arranged in the center of the heat exchanger to separate the spiral channel, and a fixed distance column is welded between the two plates to maintain the channel spacing. The advantages of the spiral plate heat exchanger are: high heat transfer coefficient; not easy to foul and block; can use lower temperature heat source; compact structure.
The disadvantages of the spiral plate heat exchanger are: the operating pressure and temperature should not be too high; it is not easy to repair.
9. heat pipe heat exchanger
The heat pipe is made up of a sealed metal pipe that extracts non-condensable gas and is filled with a certain amount of certain working liquid. The working fluid absorbs heat at the hot end and boils and vaporizes. The generated steam flows to the cold end to condense and release latent heat. The condensate returns to the hot end to boil and vaporize again. The advantages of heat pipe heat exchangers are: simple structure, long service life, reliable work; high thermal conductivity, good isothermality; the heat transfer area on both sides of the cold and heat can be changed arbitrarily, heat can be transferred over a long distance, and can be controlled temperature. The disadvantages are: poor oxidation resistance and high temperature resistance.