Sleeve type air jet heat exchanger for recovering heat of high-temperature flue gas of aluminum melting furnace

Abstract

The utility model discloses a sleeve type air jet heat exchanger for recovering heat of high-temperature flue gas of an aluminum melting furnace, which comprises a cold air box, a hot air box, a heat exchange box and a heat exchange tube, the cold air box, the hot air box and the heat exchange box are formed by separating a box body through two transverse partition plates, the upper partition plate and the lower partition plate are provided with mutually corresponding round holes, and the heat exchange tube is arranged in the heat exchange box. The upper end of an inner pipe is fixed in a round hole formed in the upper partition plate, and the lower end of the inner pipe penetrates through the hot air box, extends into the heat exchange box and is sealed; the upper end of the outer sleeve is fixed in a round hole formed in the lower partition plate, the lower end of the outer sleeve extends into the heat exchange box and is sealed, the inner pipe extends into the outer sleeve, and the inner pipe is provided with a plurality of rows of small holes in the pipe wall of the outer sleeve. The sleeve type air jet heat exchanger for recovering high-temperature flue gas heat of the aluminum melting furnace can solve the corrosion influence of high-temperature flue gas on equipment, improves the heat exchange efficiency of the heat exchanger, prolongs the service life of the heat exchanger, and reduces the maintenance difficulty and the maintenance cost.

Description

Technical Field

[0001] The utility model belongs to the technical field of heat exchange equipment and relates to a sleeve-type air jet heat exchanger used for heat recovery of high-temperature flue gas in an aluminum melting furnace. Background Art

[0002] In the past decade, due to the shortage of energy, with the further development of energy conservation work, various new and energy-saving advanced furnaces have been improved day by day, and the use of high-quality insulation materials such as new refractory fibers has significantly reduced the heat loss of furnaces. The use of advanced combustion devices has strengthened combustion, reduced the amount of incomplete combustion, and the air-fuel ratio is also reasonable. However, the technology of reducing exhaust heat loss and recovering flue gas waste heat is still not progressing fast. In order to further improve the thermal efficiency of the heating furnace and achieve the purpose of energy saving and consumption reduction, recovering flue gas waste heat is also an important way to save energy.

[0003] Since the 1950s, China has used shell-and-tube air jet heat exchangers for preheating air in industrial furnaces. However, due to the corrosion of high-temperature flue gas in aluminum melting furnaces on heat exchange equipment, the heat exchange effect is not ideal, and the service life is short at high temperatures, the maintenance workload is large or the maintenance cost is high, which greatly affects its scope of use. Summary of the invention

[0004] The utility model aims to provide a shell-and-tube air jet heat exchanger for heat recovery of high-temperature flue gas in an aluminum melting furnace, which can solve the influence of related gas corrosion on the equipment, improve heat exchange efficiency and service life, and reduce maintenance difficulty and maintenance cost.

[0005] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a shell-and-tube air jet heat exchanger for heat recovery of high-temperature flue gas in an aluminum melting furnace, which is composed of a cold air box, a hot air box, a heat exchange box and a heat exchange tube. The cold air box, the hot air box and the heat exchange box are composed of a box body separated by two horizontal partitions, and the upper partition and the lower partition are provided with corresponding circular holes. The heat exchange tube is composed of a plurality of vertical inner and outer concentric sleeves, wherein the upper end of the inner tube is fixed in the circular hole provided in the upper partition, and the lower end passes through the hot air box and extends into the heat exchange box and is sealed; the upper end of the outer sleeve is fixed in the circular hole provided in the lower partition, and the lower end extends into the heat exchange box and is sealed, the inner tube extends into the outer sleeve, and the inner tube has multiple rows of small holes on the tube wall of the outer sleeve.

[0006] The outer sleeve is a silicon carbide tube.

[0007] A buffer box is arranged in front of the heat exchange box, and a flue gas inlet and a cooling air inlet are arranged on the buffer box. When the flue gas temperature is too high and approaches the limit operating temperature of the heat exchange tube, cold air can be blown into the buffer box through the cooling air inlet to buffer and dilute the flue gas, thereby protecting the heat exchange box and the heat exchange tube.

[0008] The bottom of the heat exchange box is provided with an ash discharge port and an ash discharge valve, and the side of the heat exchange box is provided with a purge port, which is convenient for regular cleaning of smoke and dust accumulated in the box, while ensuring the use effect of the heat exchanger and extending its service life.

[0009] The lower partition is made of heat-resistant ductile iron, which can solve the effect of flue gas corrosion on the partition.

[0010] The circular holes on the upper partition plate and the lower partition plate are evenly distributed.

[0011] The interiors of the buffer box and the heat exchange box are both cast structures.

[0012] In the utility model, air is sprayed onto the inner wall of the outer tube from rows of small holes on the inner tube in a direction perpendicular to the inner wall surface of the outer tube; because the small holes are very close to the inner wall of the outer tube, the flow path of the fluid on the heat exchange surface is very short, and the jet velocity is high, so it has a high heat transfer efficiency. At the same time, the outer tube is made of silicon carbide, which not only solves the problem of flue gas corrosion but also further improves the heat exchange efficiency. The box body is divided into upper and lower structures by a partition, and the heat exchange tubes are all installed on the partition, which is easy to disassemble, repair and replace. The lower partition is in direct contact with the flue gas, and the use of heat-resistant ductile iron can solve the corrosive effect of flue gas on the equipment. At the same time, the bottom of the box body is provided with an ash discharge port, and the side of the heat exchange box is also provided with a purge port, which is convenient for regular cleaning of the smoke accumulated in the box, ensuring the use effect of the heat exchanger and extending the service life.

[0013] The utility model discloses a sleeve-type air jet heat exchanger for heat recovery of high-temperature flue gas in an aluminum melting furnace, which can solve the corrosion effect of high-temperature flue gas on equipment, while improving the heat exchange efficiency and service life of the heat exchanger and reducing the difficulty and cost of repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an explosion diagram of the utility model;

[0015] Figure 2 It is a plan view of the utility model;

[0016] Figure 3 It is a side sectional view of the utility model;

[0017] Figure 4 It is a front cross-sectional view of the utility model;

[0018] Figure 5 This is a structural diagram of the heat exchange tube of the utility model.

[0019] In the figure: 1. cold air box; 2. inner pipe; 3. upper partition; 4. hot air box; 5. outer pipe; 6. lower partition; 7. heat exchange box; 8. ash discharge valve; 9. heat exchange box bracket; 10. buffer box bracket; 11. buffer box; 12. buffer box cover; 13. cold air inlet; 14. hot air outlet; 15. purge port; 16. cooling air inlet; 17. flue gas inlet; 18. flue gas outlet. DETAILED DESCRIPTION

[0020] The utility model will be further described below in conjunction with the accompanying drawings.

[0021] from Figure 1-5 It can be seen that the utility model is a shell-and-tube air jet heat exchanger for heat recovery of high-temperature flue gas in an aluminum melting furnace, which is composed of a cold air box 1, a hot air box 4, a heat exchange box 7 and a heat exchange tube. The cold air box and the hot air box are respectively provided with a cold air inlet 13 and a hot air outlet 14, and the heat exchange box 7 has a flue gas outlet 18 and a connecting channel for the flue gas inlet. Figure 2-5 It can be seen that the cold air box, hot air box and heat exchange box are separated by two horizontal partitions arranged above and below a box body. The upper partition 3 and the lower partition 6 are evenly provided with corresponding concentric circular holes. The upper partition 3 is a stainless steel plate, and the lower partition 6 is a partition made of heat-resistant ductile iron, which can solve the influence of flue gas corrosion on the partition. The heat exchange tube is composed of multiple vertical inner and outer concentric sleeves, wherein the inner tube 2 is a stainless steel tube, the upper end of which is fixed in the circular hole opened in the upper partition 3, and the lower end passes through the hot air box and extends into the heat exchange box and is sealed; the outer sleeve is a silicon carbide tube, the upper end of which is fixed in the circular hole opened in the lower partition 6, and the lower end extends into the heat exchange box and is sealed, and the inner tube extends into the outer sleeve, and the inner tube has multiple rows of small holes on the tube wall of the outer sleeve.

[0022] When the flue gas temperature is too high and approaches the maximum operating temperature of the heat exchange tube, a buffer box can be installed in front of the connecting channel of the heat exchange box. The buffer box is provided with a flue gas inlet and a cooling air inlet. In this way, cold air is blown into the buffer box through the cooling air inlet to buffer and dilute the flue gas, reduce the flue gas temperature, and protect the heat exchange box and heat exchange tube.

[0023] The interiors of the buffer box 11 and the heat exchange box 7 are both cast structures. The bottom of the heat exchange box is provided with an ash discharge port and an ash discharge valve 8, and the side of the heat exchange box is provided with a purge port 15, which is convenient for regular cleaning of smoke and dust accumulated in the box, thereby ensuring the use effect of the heat exchanger and extending its service life.

[0024] Cold air enters the cold air box 1 from the cold air inlet 13, and then passes through rows of small holes on the wall of the inner tube 2, sprays to the inner wall of the outer tube made of silicon carbide for heat exchange, enters the hot air box 4 through the annular gap above the outer tube, and finally enters the air supply duct through the hot air outlet 14. The flue gas enters the buffer box 11 from the flue gas inlet 17, and is mixed and diluted with the cold air entering from the cooling air inlet 16 above to reach a safe temperature, then enters the heat exchange box 7 through the channel to contact the heat exchange tube for heat exchange, and then enters the main smoke pipe through the flue gas outlet 18 and then merges into the dust removal equipment.

[0025] The above shows and describes the basic principles and main features of the utility model and the advantages of the utility model. Those skilled in the art should understand that the utility model is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which shall fall within the scope of the utility model to be protected. The scope of protection of the utility model shall be defined by the attached claims and their equivalents.

Claims

1. A shell-and-tube air jet heat exchanger for heat recovery of high-temperature flue gas from an aluminum melting furnace, characterized in that: It is composed of a cold air box, a hot air box, a heat exchange box and a heat exchange tube. The cold air box, the hot air box and the heat exchange box are divided into a box body by two horizontal partitions. The upper partition and the lower partition are provided with corresponding circular holes. The heat exchange tube is composed of a plurality of vertical inner and outer concentric sleeves, wherein the upper end of the inner tube is fixed in the circular hole provided in the upper partition, and the lower end passes through the hot air box and extends into the heat exchange box and is sealed; the upper end of the outer sleeve is fixed in the circular hole provided in the lower partition, and the lower end extends into the heat exchange box and is sealed. The inner tube extends into the outer sleeve, and the inner tube has multiple rows of small holes on the tube wall of the outer sleeve.

2. The shell-and-tube air jet heat exchanger for heat recovery of high-temperature flue gas from an aluminum melting furnace according to claim 1 is characterized in that: The outer sleeve is a silicon carbide tube.

3. The shell-and-tube air jet heat exchanger for heat recovery of high-temperature flue gas from an aluminum melting furnace according to claim 1 is characterized in that: A buffer box is arranged in front of the heat exchange box, and a smoke inlet and a cooling air inlet are arranged on the buffer box.

4. The shell-and-tube air jet heat exchanger for heat recovery of high-temperature flue gas from an aluminum melting furnace according to claim 1 is characterized in that: The bottom of the heat exchange box is provided with an ash discharge port and an ash discharge valve, and the side of the heat exchange box is provided with a purge port.

5. The shell-and-tube air jet heat exchanger for heat recovery of high-temperature flue gas from an aluminum melting furnace according to claim 1 is characterized in that: The lower partition is made of heat-resistant ductile iron.

6. The shell-and-tube air jet heat exchanger for heat recovery of high-temperature flue gas from an aluminum melting furnace according to claim 1 is characterized in that: The circular holes on the upper partition plate and the lower partition plate are evenly distributed.

7. The shell-and-tube air jet heat exchanger for heat recovery of high-temperature flue gas from an aluminum melting furnace according to claim 3 is characterized in that: The interiors of the buffer box and the heat exchange box are both cast structures.

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