Integrated air-fuel gas integrated preheating device and preheating method

Abstract

An integrated air-fuel gas integrated preheating device is composed of an air preheating unit and a fuel gas preheating unit, wherein the air preheating unit and the fuel gas preheating unit are arranged in an inner cavity of the same preheater shell in an up-down nested mode. The air preheating unit is arranged in the center of an inner cavity of the preheater shell. The air preheating unit comprises an air heat exchanger, a cold air collector ring and a hot air collector ring. The fuel gas preheating unit is arranged around the outer side of the air preheating unit and comprises a hot fuel gas collecting tank, a fuel gas heat exchange pipe and a fuel gas collecting pipe; a flue gas isolating ring plate which is relatively isolated and has a through function is arranged between the fuel gas preheating unit and the air preheating unit, so that the fuel gas preheating unit and the air preheating unit form a preheating system which is relatively independent and can locally communicate with each other; and a hot fuel gas collecting tank is arranged at the top of the inner cavity of the preheater shell.

Description

Technical Field

[0001] The invention relates to an integrated air-gas integrated preheating device and a preheating method, belonging to the technical field of industrial flue gas waste heat recovery. Background Art

[0002] Using high-temperature flue gas waste heat to preheat combustion air or gas is an important means of energy conservation and emission reduction in industrial production, and is also a common configuration in industrial furnace equipment. At present, most industrial furnaces are equipped with combustion air preheating devices to preheat the combustion air to 300-500℃ (regenerative combustion can preheat the combustion air to 800-1000℃). Some industrial furnaces are also equipped with dual preheating devices for combustion air and gas, which can maximize the recovery of flue gas waste heat, save energy, reduce emissions and reduce production costs.

[0003] Generally, when the calorific value of gas is low (gas calorific value ≤ 8000kJ / Nm 3 ), most of them adopt the dual preheating method of gas and air. The common method is to arrange the combustion air preheater and the gas preheater in series, that is, to preheat the combustion air with high-temperature flue gas first, and then preheat the gas. This arrangement has the following disadvantages:

[0004] 1) The preheater requires a lot of space;

[0005] 2) The connection between the two preheaters must be equipped with insulation facilities, and the connecting flange is easy to be damaged.

[0006] However, if the space in the industrial furnace area is small, air-gas dual preheating cannot be achieved, resulting in a large amount of flue gas waste heat waste, and the furnace fuel combustion effect is not good.

[0007] Therefore, how to solve the difficulty of achieving dual preheating of air and gas in a small space and improve the heat exchange efficiency of the preheater is still one of the issues that need to be solved urgently in this field. Summary of the invention

[0008] The purpose of the present invention is to develop an integrated air-gas preheating device and preheating method to solve the problem of air-gas dual preheating in a small space, which not only greatly reduces the volume of the preheater and improves the heat exchange efficiency of the preheater, but also saves the investment cost of the preheater equipment.

[0009] The above invention object is achieved through the following technical solutions:

[0010] This integrated air-gas preheating device is characterized in that it is composed of an air preheating unit and a gas preheating unit which are stacked up and down and arranged in the same preheater shell 7 cavity; the air preheating unit is arranged at the center of the cavity of the preheater shell 7, and the air preheating unit includes an air heat exchanger 11, a cold air collector ring 18 and a hot air collector ring 5; the gas preheating unit is arranged around the outside of the air preheating unit, and the gas preheating unit includes a hot gas collecting box 14, a gas heat exchanger 9, and a gas collecting pipe 12; a flue gas isolation ring plate 10 is provided between the gas preheating unit and the air preheating unit, which is relatively isolated and can also play a through-connection role, so that the two become preheating systems that are relatively independent of each other and can communicate with each other locally; the hot gas collecting box 14 is arranged at the top of the cavity of the preheater shell 7.

[0011] Furthermore, the air heat exchanger 11 is composed of a plurality of air heat exchange tubes 11.1 distributed in a ring shape in the vertical center of the inner cavity of the integrated preheater shell, and each air heat exchange tube 11.1 is connected to the inner cavity of the cold air collecting ring 18 arranged at the upper part, and the lower part of each air heat exchange tube is connected to the inner cavity of the hot air collecting ring 5 arranged at the bottom of the inner cavity of the integrated preheater shell; the cold air collecting ring 18 forms a combustion air inlet 19 through a tube body extending outside the preheater shell 7.

[0012] Furthermore, the gas heat exchanger 9 is composed of gas heat exchange tubes 9.1 distributed in a ring shape on the outer circle of the air heat exchange tubes 11.1 which are also distributed in a ring shape. The upper end of each gas heat exchange tube 9.1 is connected to the inner cavity of the hot gas collecting box 14 arranged at the top of the inner cavity of the preheater shell 7, and the lower end thereof is connected to the cold gas descending channel 8 arranged on the inner wall of the preheater shell 7.

[0013] Furthermore, the hot gas collecting box 14 is composed of a circular gas isolation plate 24, a preheater cover and an insulation layer 16 arranged on the top of the inner cavity of the preheater shell 7. The upper part of each gas heat exchange tube 9.1 is connected to the inner cavity of the hot gas collecting box 14. At the same time, an outlet 15 for providing heated hot gas to the outside is provided on one side of the hot gas collecting box 14.

[0014] Furthermore, the cold gas descending channel 8 is a circle of space interlayer arranged on the inner wall of the preheater shell 7, and its lower part is connected with each annularly distributed gas heat exchange pipe 9.1 in the gas preheating unit through a through hole, and its upper part is connected with the gas collecting pipe 12 arranged outside the shell of the preheater shell 7 at this position through the gas inlet hole 13 arranged on the preheater shell 7; the gas collecting pipe 12 is provided with a cold gas inlet 20 connected to the gas supply source.

[0015] Furthermore, the height of the flue gas isolation ring plate 10 is lower than the height of the annularly distributed air heat exchange tubes 11.1 in the air preheating unit; and the lower part of the flue gas isolation ring plate 10 is fixed on the inner bottom of the preheater chassis 2, and the upper part of the flue gas isolation ring plate 10 is fixed on the inner wall of the preheater shell 7 through the smoke isolation ring plate support rod 23 arranged outside the smoke gas isolation ring plate.

[0016] Furthermore, the hot air collecting ring 5 extends out of the preheater housing 7 through a hot air input pipe arranged in a horizontal direction to form a hot air outlet 6.

[0017] Furthermore, the hot air collecting ring 5 is connected to the preheater chassis 2 via a plurality of hot air collecting ring supporting legs 4 connected to the bottom thereof.

[0018] Furthermore, the preheater chassis 2 is annular, and an annular flue gas rising channel isolation wall 3 is provided on the inner ring edge of the annular ring. The upper part of the flue gas rising channel isolation wall 3 is sealed and connected to the bottom of the hot air collecting ring 5, forming a flue gas rising channel connected to the high-temperature flue gas inlet 1.

[0019] Furthermore, a high-temperature flue gas inlet 1 is provided at the bottom of the preheater shell 7, so that it is directly connected to the space enclosed by the air heat exchanger 11 and the flue gas rising channel partition wall 3 and the flue gas isolation ring plate 10 through the inner circle of the hot air collecting ring 5, forming a high-temperature flue gas rising channel from bottom to top.

[0020] Furthermore, a plurality of conical smoke guide plates 22 are provided in the cylindrical cavity surrounded by the air heat exchange tubes 11.1, and are interlaced and sleeved with the surrounding air heat exchange tubes, and have a V-shaped cone in the middle. The outer periphery of the conical smoke guide plate 22 is fixedly connected to the smoke isolation ring plate 10, forming a layered smoke horizontal diffusion structure from bottom to top.

[0021] Furthermore, a hot gas outlet 15 for providing high-temperature gas to the outside is provided on the shell on one side of the upper part of the preheater shell 7, and the hot gas outlet 15 is connected to the hot gas collecting box 14 in the upper inner cavity of the preheater shell 7; a flue gas discharge port 21 connected to the lower part of the preheater shell 7 is provided at the lower part of the shell on the other side of the preheater shell 7.

[0022] Furthermore, a set of preheater lifting rings 17 for installing the integrated air-gas preheating device is provided on the top outer shell of the preheater shell 7.

[0023] When in use, the integrated preheating device is connected to the exhaust channel of the industrial furnace, that is, the high-temperature flue gas inlet 1 at the lower part is connected to the high-temperature flue gas outlet discharged from the industrial furnace, and the flue gas discharge port 21 of the integrated preheating device is connected to the exhaust pipe connected to the exhaust fan or the exhaust smoke window; the cold air inlet 19 and the cold gas inlet 20 are connected to the cold air source and the cold gas inlet source respectively.

[0024] The preheating process is as follows:

[0025] 1) When the high-temperature flue gas enters the center of the preheater from the high-temperature flue gas inlet 1 at the bottom of the integrated preheating device, it moves upward along the columnar space formed by the flue gas isolation ring plate 10 under the guidance of the conical flue gas guide plate 22 in the channel formed by the flue gas isolation ring plate 10, so that it fully contacts each air heat exchange tube 11.1 of the air heat exchanger 11 arranged in the middle columnar space of the preheater shell 7, so that the air passing through the heat exchanger tube bundle area is preheated; at the same time, as the rising high-temperature flue gas moves downward along the outer side of the flue gas isolation ring plate, it fully contacts each gas heat exchanger 9 tube bundle in the gas heat exchange unit during the downward movement process, so that the gas in the inner cavity of the gas heat exchange tube 9.1 tube bundle is heated, and at the same time, the descending flue gas continues to make the flue gas in the air heat exchange tube 11.1 after two heat exchanges move along the outer circle of the flue gas isolation ring plate 10 and is discharged from the flue gas discharge port 21 at the bottom of the preheater;

[0026] 3) At the same time, the outside cold air enters the cold air collecting ring 18 from the combustion air inlet 19, and is evenly distributed to each air heat exchange tube 11.1 of the cold air heat exchanger 11, and moves downward along the inner cavity of each air heat exchange tube 11.1 constituting the air heat exchanger 11, and performs heat exchange with the high-temperature flue gas rising from the flue gas inlet 1 arranged at the lower part of the preheater shell 7 in countercurrent; the preheated air in the tube is collected in the hot air collecting ring 5 at the lower part, and then supplied to the burner of the using device through the hot air outlet 6 connected to the hot air collecting ring 5;

[0027] 4) At the same time, the cold gas enters the gas collecting pipe 12 from the cold gas inlet 20, and then the gas is evenly distributed into the cold gas descending channel 8 through the descending channel holes 13 arranged between the shell wall of the preheater shell 7 and the cold gas descending channel 8, moves downward along the inner wall of the preheater shell 7, and enters the inner cavity of each gas heat exchange tube 9.1 tube bundle constituting the gas heat exchange unit through the lower part of the cold gas descending channel 8, moves upward, and realizes countercurrent heat exchange with the high-temperature flue gas descending along the outer side of the flue gas isolation ring plate 10; the preheated gas in the tube rises and enters the hot gas collecting box 14, and is supplied to the use device - the burner through the hot gas outlet 15.

[0028] The integrated air-gas preheating device proposed according to the above technical solution has the following advantages:

[0029] 1) The volume of the air-gas dual preheating device is greatly reduced, and air-gas dual preheating can be achieved in a small space, greatly reducing energy consumption.

[0030] 2) The comprehensive heat transfer coefficient of the preheater is 30~40W / (m 2 .℃), which is greater than the heat transfer coefficient of conventional preheaters, greatly improving the heat transfer efficiency of preheaters.

[0031] 3) When this preheater is used, when the inlet flue gas temperature is 900-1050°C, the air preheating temperature can reach 460-550°C, and the gas preheating temperature can reach 420-500°C.

[0032] 4) The preheater adopts the method of cold gas flowing downward along the inner wall of the preheater shell, so that the preheater shell does not heat up. The preheater shell reduces or does not use insulation materials.

[0033] 5) The preheater is easy to disassemble. When the dust inside the preheater is seriously accumulated after a certain period of use, the gas preheating part and the air preheating part can be easily separated to clean the dust. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0035] Figure 2 It is a top view of the lower part of the integrated air-gas preheater;

[0036] Figure 3 It is the AA section view of the integrated preheater;

[0037] Figure 4 It is a schematic diagram of the inlet and outlet distribution of gas, smoke and air of the present invention.

[0038] In the figure:

[0039] 1- High-temperature flue gas inlet; 2- Preheater chassis; 3- Flue gas ascending channel partition wall;

[0040] 4-hot air collecting ring support leg; 5-hot air collecting ring; 6-hot air outlet;

[0041] 7-preheater shell; 8-cold gas descending channel; 9-gas heat exchanger;

[0042] 9.1-gas heat exchange pipe; 10-smoke isolation ring plate; 11-air heat exchanger;

[0043] 11.1- air heat exchange pipe; 12- gas collecting pipe;

[0044] 13-Gas enters the descending channel hole; 14-hot gas collecting box;

[0045] 15-hot gas outlet; 16-preheater cover and insulation layer; 17-preheater lifting ring;

[0046] 18-cold air collecting ring; 19-cold air inlet; 20-cold gas inlet;

[0047] 21-smoke discharge port; 22-conical smoke guide plate;

[0048] 23-Smoke isolation ring plate support rod. DETAILED DESCRIPTION

[0049] The core idea of ​​the integrated air-gas preheating device proposed according to the above technical solution is that the air-gas dual preheating units are arranged in the same preheater cavity, which not only greatly reduces the volume of the entire device, but also greatly improves the heat exchange efficiency; at the same time, it can not only be used in the field of industrial furnace flue gas waste heat recovery, but also can be used for high-temperature flue gas waste heat recovery and utilization in other industries.

[0050] The present invention is further described below in conjunction with embodiments, and specific embodiments of the present invention are given.

[0051] This integrated air-gas integrated preheater device is characterized in that it is composed of an air preheating unit and a gas preheating unit which are stacked up and down and arranged in the same preheater shell 7 cavity; the air preheating unit is arranged at the center of the cavity of the preheater shell 7, and the air preheating unit includes an air heat exchanger 11, a cold air collector ring 18 and a hot air collector ring 5; the gas preheating unit is arranged around the outside of the air preheating unit, and the gas preheating unit includes a hot gas collecting box 14, a gas heat exchanger 9, and a gas collecting pipe 12; a flue gas isolation ring plate 10 is provided between the gas preheating unit and the air preheating unit, which is relatively isolated and can also play a through-connection role, so that the two become preheating systems that are relatively independent of each other and can communicate with each other locally; the hot gas collecting box 14 is arranged at the top of the cavity of the preheater shell 7.

[0052] The air heat exchanger 11 is composed of a plurality of air heat exchange tubes 11.1 distributed in a ring shape at the central part of the inner cavity of the integrated preheater shell in the vertical direction. Each air heat exchange tube 11.1 is connected to the inner cavity of the cold air collecting ring 18 arranged at the upper part, and the lower part of each air heat exchange tube is connected to the inner cavity of the hot air collecting ring 5 arranged at the bottom of the inner cavity of the integrated preheater shell; the cold air collecting ring 18 forms a combustion air inlet 19 through the tube body extending out of the preheater shell 7. The cold air flows downward through the air heat exchange tube 11.1 tube bundle and performs countercurrent heat exchange with the upward high-temperature flue gas. The preheated air enters the hot air collecting ring 5, and the collected hot air is sent to the device for use through the hot air outlet 6.

[0053] The gas heat exchanger 9 is composed of gas heat exchange tubes 9.1 distributed in a ring shape on the outer circle of the air heat exchange tubes 11.1 which are also distributed in a ring shape. The upper end of each gas heat exchange tube 9.1 is connected to the inner cavity of the hot gas collecting box 14 arranged at the top of the inner cavity of the preheater shell 7, and the lower end is connected to the cold gas descending channel 8 arranged on the inner wall of the preheater shell 7.

[0054] The gas heat exchange pipe 9 is composed of several "J" metal bends along the circumferential direction of the preheater. The lower elbow of the metal pipe is connected to the lower part of the cold gas descending channel 8, and the upper end is connected to the hot gas collecting box 14, forming an on-site gas and flue gas heat exchange channel.

[0055] The cold gas descending channel 8 is a circle of space interlayer arranged on the inner wall of the preheater shell 7, and its lower part is connected with each annularly distributed gas heat exchange pipe 9.1 in the gas preheating unit through a through hole, and its upper part is connected with the gas collecting pipe 12 arranged outside the shell of the preheater shell 7 at this position through the gas inlet hole 13 arranged on the preheater shell 7; the gas collecting pipe 12 is provided with a cold gas inlet 20 connected to the gas supply source.

[0056] The gas collecting pipe 12 is composed of a metal "C"-shaped or rectangular plate and a part of the preheater shell 7. The gas collecting pipe 12 is fixed on the preheater shell 7. Several through gas inlet holes 13 are opened on the component of the preheater shell 7 to connect the gas collecting pipe 12 with the cold gas descending channel 8.

[0057] The cold gas entering through the cold gas inlet 20 is distributed to the cold gas descending channel 8 through the cold gas collecting pipe 12 and the gas entering descending channel hole 13. The cold gas enters the gas heat exchanger 9 through the lower part of the cold gas descending channel 8, and the gas flows upward and exchanges heat with the downward high-temperature flue gas in the reverse direction, and then is collected in the hot gas collecting box 14, and is sent to the device (burner) for use through the hot gas outlet 15. After the high-temperature flue gas enters the preheater from the high-temperature flue gas inlet 1, it goes upward from the center of the preheater and exchanges heat with the air heat exchanger 11, then turns over the flue gas isolation ring plate 10 and continues to exchange heat with the gas heat exchanger 9 downward, and is discharged from the flue gas discharge port 21.

[0058] Several conical flue gas guide plates 22 are arranged on the central channel of the preheater to guide the high-temperature flue gas to the surrounding of the tube bundle of the air heat exchanger 11. The conical flue gas guide plates 22 are made of conical heat-resistant steel plates. The preheater is provided with multiple conical flue gas guide plates 22 from bottom to top (two are arranged in this case), and 4 to 6 flue gas isolation ring plate support rods 23 are arranged around the periphery thereof and fixed to the preheater housing 7.

[0059] The height of the flue gas isolation ring plate 10 is lower than the height of the annularly distributed air heat exchange tubes 11 in the air preheating unit; and the lower part of the flue gas isolation ring plate 10 is fixed on the inner bottom of the preheater chassis 2, and the upper part of the flue gas isolation ring plate 10 is fixed on the inner wall of the preheater shell 7 through the flue gas isolation ring plate support rod 23 arranged outside the flue gas isolation ring plate. The flue gas isolation ring plate 10 is composed of a cylindrical steel plate, the lower part of the cylindrical steel plate is fixed on the preheater chassis 2, and the upper end is located about 200mm below the cold air collecting ring 18. The cold air collecting ring 18 is located at the upper part of the preheater, and the cross section is a rectangular or circular ring tube. The cold air inlet 19 is placed on the side of the cold air collecting ring 18. The lower part of the cold air collecting ring 18 is connected to the air heat exchanger 11 tube bundle. The cold air collecting ring 18 is located at the upper part of the preheater, and the cross section is a rectangular or circular ring tube. The cold air inlet 19 is disposed on the side of the cold air collecting ring 18. The lower part of the cold air collecting ring 18 is connected to the tube bundle of the air heat exchanger 11.

[0060] The hot air collecting ring 5 extends out of the preheater housing 7 through a hot air inlet pipe arranged in a horizontal direction to form a hot air outlet 6.

[0061] The hot air collecting ring 5 is connected to the preheater chassis 2 through a plurality of hot air collecting ring support legs 4 connected to the bottom thereof. The hot air collecting ring 5 is located at the lower part of the preheater, and its shape can be a rectangular ring or a circular ring. The lower part of the hot air collecting ring 5 is fixed to the preheater chassis 2 by the hot air collecting ring support legs 4. It is connected to the partition wall 3 of the flue gas ascending channel. The upper part of the hot air collecting ring 5 is connected to the tube bundle of the air heat exchanger 11.

[0062] The preheater chassis 2 is annular, and an annular flue gas ascending channel isolation wall 3 is provided on the inner edge of the annular ring. The upper part of the flue gas ascending channel isolation wall 3 is sealed and connected to the bottom of the hot air collecting ring 5 to form a flue gas ascending channel.

[0063] The center of the bottom of the integrated air-gas preheater is a circular high-temperature flue gas inlet 1, and the hot air collecting ring 5 is fixed on the preheater chassis 2 through the hot air collecting ring support legs 4. The hot air outlet 6 is arranged on the hot air collecting ring 5. The cold air collecting ring 18 is located above the hot air collecting ring 5, and the cold air collecting ring 18 and the hot air collecting ring 5 are connected; the cold air inlet 19 is arranged on the cold air collecting ring 18.

[0064] A high-temperature flue gas inlet 1 is provided at the bottom of the preheater shell 7, so that it is directly connected to the space enclosed by the air heat exchange pipe 11 and the flue gas rising channel partition wall 3 and the flue gas isolation ring plate 10 through the inner circle of the hot air collecting ring 5, forming a high-temperature flue gas rising channel from bottom to top.

[0065] A gas collecting pipe 12 is arranged on the upper part of the preheater shell 7, and a cold gas inlet 20 is arranged on the gas collecting pipe 12. A plurality of gas entry descending channel holes 13 are arranged on the circumference of the preheater shell 7 where the gas collecting pipe 12 is located. The holes connect the gas collecting pipe 12 with the cold gas descending channel 8, the lower part of the cold gas descending channel 8 is connected to the lower part of the gas heat exchange pipe 9, and the upper part of the gas heat exchange pipe 9 is connected to the hot gas collecting box 14, and the hot gas collecting box 14 is located above the cold air collecting ring 18. The upper part of the hot gas collecting box 14 is the preheater upper cover and the insulation layer 16. The preheater upper cover and the insulation layer 16 are provided with a preheater lifting ring 17.

[0066] The integrated preheater composed of the above components can greatly reduce the volume of the air-gas dual preheating device and greatly improve the heat exchange efficiency. It can be used not only in the field of industrial furnace flue gas waste heat recovery, but also in the high-temperature flue gas waste heat recovery and utilization in other industries.

[0067] The flue gas isolation ring plate 10 is composed of a cylindrical steel plate, the lower part of which is fixed on the preheater chassis 2, and the upper end is located about 200 mm below the cold air collecting ring 18. A flue gas isolation ring plate support rod 23 is provided on the upper part of the flue gas isolation ring plate 10 to fix it on the preheater shell 7.

[0068] The upper part of the hot gas collecting box 14 is the upper cover of the preheater and the heat-insulating layer 16, and the lower part is connected with the tube bundle of the gas heat exchange tube 9. The hot gas outlet 15 is arranged on the side thereof.

[0069] The integrated air-gas preheater also includes a high-temperature flue gas inlet 1, so that the high-temperature flue gas enters the preheater from bottom to top. A preheater lifting ring 17 is provided on the preheater upper cover and the insulation layer 16 for lifting and moving the preheater.

[0070] The preheating process of the integrated air-gas preheater is as follows:

[0071] The integrated air-gas preheater is connected to the exhaust channel of the industrial furnace, that is, the high-temperature flue gas inlet 1 at the lower part is connected to the high-temperature flue gas exhausted from the industrial furnace, and the flue gas outlet 21 is connected to the exhaust pipe (connected with a smoke exhaust fan or a smoke exhaust window).

[0072] The high-temperature flue gas enters the center of the preheater from the high-temperature flue gas inlet 1 at the bottom, and moves upward along the circumference of the flue gas isolation ring plate 10 under the guidance of the conical flue gas guide plate 22 in the channel of the flue gas isolation ring plate 10, fully contacts the tube bundle of the air heat exchanger 11, and preheats the air in the tube bundle of the air heat exchanger 11. The high-temperature flue gas reaches the upper part of the flue gas isolation ring plate 10, turns over the flue gas isolation ring plate 10 and moves downward, fully contacts the tube bundle of the gas heat exchanger 9, and preheats the gas in each tube bundle of the gas heat exchange tube 9.1. After two heat exchanges, the flue gas moves along the outer ring of the flue gas isolation ring plate 10 and is discharged from the flue gas discharge port 21 at the bottom of the preheater;

[0073] Cold air enters the cold air collecting ring 18 from the cold air inlet 19, is evenly distributed to the tube bundle of the air heat exchanger 11, moves downward along the air heat exchanger 11, and exchanges heat with the rising high-temperature flue gas in countercurrent. The preheated air is collected in the hot air collecting ring 5 and supplied to the burner through the hot air outlet 6.

[0074] The cold gas enters the gas collecting pipe 12 from the cold gas inlet 20, is evenly distributed to the cold gas descending channel 8 through the gas entering descending channel hole 13, moves downward along the inner wall of the preheater shell 7, enters the gas heat exchange tube 9 bundle at the lower part of the cold gas descending channel 8, moves upward, and exchanges heat with the descending high-temperature flue gas in countercurrent. The preheated gas enters the hot gas collecting box 14 and is supplied to the use device (burner) through the hot gas outlet 15.

[0075] The preheater fundamentally solves the problem of not being able to achieve air-gas dual preheating in a small space, greatly improves the flue gas waste heat recovery efficiency, and is a highly efficient device for energy conservation, emission reduction, and production cost reduction.

[0076] The above is merely the basic implementation of the present invention given by the applicant based on the technical solution. Any improvement without substantial creativity made by any ordinary technician in the industry with reference to the technical solution shall be deemed to fall within the protection scope of the present invention.

Claims

1. An integrated air-gas preheating device, characterized in that: It consists of an air preheating unit and a gas preheating unit which are arranged in a stacked manner in the same preheater shell (7); the air preheating unit is arranged at the center of the preheater shell (7) inner cavity, and the air preheating unit includes an air heat exchanger (11), a cold air collector ring (18) and a hot air collector ring (5); the gas preheating unit is arranged around the outer side of the air preheating unit, and the gas preheating unit includes a hot gas collecting box (14), a gas heat exchanger (9) and a gas collecting pipe (12); a flue gas isolation ring plate (10) which is relatively isolated and can also play a through-connection role is provided between the gas preheating unit and the air preheating unit, so that the two become a preheating system which is both relatively independent and can communicate with each other locally; the hot gas collecting box (14) is arranged at the top of the inner cavity of the preheater shell 7.

2. An integrated air-gas preheating device as claimed in claim 1, characterized in that: The air heat exchanger (11) is composed of a plurality of air heat exchange tubes (11.1) distributed in a ring shape at the central part of the inner cavity of the integrated preheater in the vertical direction. Each air heat exchange tube (11.1) is connected to the inner cavity of the cold air collecting ring (18) arranged at the upper part, and the lower part of each air heat exchange tube is connected to the inner cavity of the hot air collecting ring (5) arranged at the lower part of the inner cavity of the integrated preheater shell; the cold air collecting ring (18) forms a combustion air inlet (19) by extending the outer tube body of the preheater shell (7).

3. The integrated air-gas preheating device according to claim 1, characterized in that: The gas heat exchangers (9) are distributed in a ring shape on the outer ring of the air heat exchange tubes (11.1) which are also distributed in a ring shape. The upper end of each gas heat exchange tube (9.1) is connected to the inner cavity of the hot gas collecting box (14) arranged at the top of the inner cavity of the preheater shell (7), and the lower end is connected to the cold gas descending channel (8) arranged on the inner wall of the preheater shell (7).

4. The integrated air-gas preheating device according to claim 1, characterized in that: The hot gas collecting box (14) is composed of a circular gas isolation plate (24), a preheater cover and a heat-insulating layer (16) arranged on the top of the inner cavity of the preheater shell (7), and the upper part of each gas heat exchange pipe (9.1) is connected to the inner cavity of the hot gas collecting box (14). At the same time, an outlet (15) for providing heated gas to the outside is provided on one side of the hot gas collecting box (14).

5. The integrated air-gas preheating device according to claim 3, characterized in that: The cold gas descending channel (8) is a space interlayer arranged on the inner wall of the preheater shell (7), the lower part of which is connected to each annularly distributed gas heat exchange pipe (9.1) in the gas preheating unit through a through hole, and the upper part of which is connected to a gas collecting pipe (12) arranged outside the shell of the preheater shell (7) at this position through a gas inlet hole (13) arranged on the preheater shell (7); the gas collecting pipe (12) is provided with a cold gas inlet (20) connected to a gas supply source.

6. The integrated air-gas preheating device according to claim 1, characterized in that: The height of the flue gas isolation ring plate (10) is lower than the height of the annularly distributed air heat exchange tubes (11.1) in the air preheating unit; and the lower part of the flue gas isolation ring plate (10) is fixed to the inner bottom of the preheater chassis (2), and the upper part of the flue gas isolation ring plate (10) is fixed to the inner wall of the preheater shell (7) through a flue gas isolation ring plate support rod (23) arranged outside the flue gas isolation ring plate.

7. The integrated air-gas preheating device according to claim 2, characterized in that: The hot air collecting ring (5) extends out of the preheater housing (7) through a hot air inlet pipe arranged in a horizontal direction to form a hot air outlet (6).

8. The integrated air-gas preheating device according to claim 1, characterized in that: The hot air collecting ring (5) is connected to the preheater chassis (2) via a plurality of hot air collecting ring supporting legs (4) connected to the bottom thereof.

9. The integrated air-gas preheating device according to claim 7, characterized in that: The preheater chassis (2) is annular, and an annular flue gas ascending channel isolation wall (3) is provided at the inner edge of the annular ring. The upper part of the flue gas ascending channel isolation wall (3) is sealedly connected to the bottom of the hot air collecting ring (5), forming an ascending channel connected to the high-temperature flue gas inlet 1.

10. The integrated air-gas preheating device according to claim 1, characterized in that: A high-temperature flue gas inlet (1) is provided at the bottom of the preheater shell (7), so that it is directly connected to the space enclosed by the air heat exchanger (11) and the flue gas rising channel partition wall (3) and the flue gas isolation ring plate (10) through the inner ring of the hot air collecting ring (5), thereby forming a high-temperature flue gas rising channel from bottom to top.

11. The integrated air-gas preheating device according to claim 1, characterized in that: A conical smoke guide plate (22) having a V-shaped cone in the middle is provided in the cylindrical cavity surrounded by the air heat exchange tubes (11.1). The conical smoke guide plate (22) is inserted and sleeved with the surrounding air heat exchange tubes. The outer periphery of the conical smoke guide plate (22) is fixedly connected to the smoke isolation ring plate (10), forming a multi-layer smoke horizontal diffusion structure from bottom to top.

12. The integrated air-gas preheating device according to claim 1, characterized in that: A hot gas outlet (15) for supplying high-temperature gas to the outside is provided on the shell on one side of the upper part of the preheater shell (7), and the hot gas outlet (15) is connected to a hot gas collecting box (14) in the upper inner cavity of the preheater shell (7); and a smoke exhaust port (21) connected to a lower box of the preheater shell (7) is provided at the lower part of the shell on the other side of the preheater shell (7).

13. The integrated air-gas preheating device according to claim 1, characterized in that: A set of preheater hanging rings (17) for installing the integrated air-gas preheating device is provided on the top outer shell of the preheater shell (7).

14. An integrated air-gas preheating device as claimed in claims 1 to 14, characterized in that: When in use, the integrated preheating device is connected to the exhaust passage of the industrial furnace, that is, the high-temperature smoke inlet (1) at the bottom is connected to the high-temperature smoke outlet discharged from the industrial furnace, so that the smoke exhaust port (21) of the integrated preheating device is connected to the smoke exhaust pipe connected to the smoke exhaust fan or the smoke exhaust window; the cold air inlet (19) and the cold gas inlet (20) are connected to the cold air source and the cold gas inlet source respectively.

15. An integrated air-gas preheating device as claimed in claims 1 to 13, characterized in that: The preheating process is as follows: 1) When the high-temperature flue gas enters the central part of the preheater from the high-temperature flue gas inlet (1) at the lower part of the integrated preheating device, it moves upward along the columnar space enclosed by the flue gas isolation ring plate (10) under the guidance of the conical flue gas guide plate (22) in the channel formed by the flue gas isolation ring plate (10), so that it fully contacts each air heat exchange tube (11.1) of the air heat exchanger (11) arranged in the middle columnar space of the preheater shell 7, so that the air passing through the air heat exchanger tube bundle area is preheated; 2) At the same time, when the high-temperature flue gas in the air heat exchange tube (11) reaches the upper part of the flue gas isolation ring plate (10), it turns over the flue gas isolation ring plate (10) and moves downward along the outer side of the flue gas isolation ring plate. In the process of moving downward, it fully contacts each tube bundle of the gas heat exchange tube (9.1) constituting the gas heat exchange unit, so that the gas in the tube bundle of the preheating gas heat exchanger (9) is heated. At the same time, the downward flue gas continues to make the flue gas in the air heat exchanger (11) that has undergone two heat exchanges move along the outer ring of the flue gas isolation ring plate (10), and finally is discharged from the flue gas discharge port (21) at the bottom of the preheater; 3) At the same time, the external cold air enters the cold air collecting ring (18) through the cold air inlet (19), is evenly distributed to each air heat exchange tube (11.1) of the air heat exchanger (11), moves downward along the inner cavity of each air heat exchange tube (11.1) constituting the air heat exchanger (11), and performs heat exchange in countercurrent with the high-temperature flue gas rising from the flue gas inlet (1); The preheated air is collected in the hot air collecting ring (5) at the bottom, and then supplied to the burner of the using device through the hot air outlet (6); 4) At the same time, the cold gas enters the gas collecting pipe (12) from the cold gas inlet (20), and then the gas is evenly distributed into the cold gas descending channel (8) through the descending channel hole (13) provided between the shell wall of the preheater shell 7 and the cold gas descending channel 8, moves downward along the inner wall of the preheater shell (7), and enters each gas heat exchange tube (9) bundle through the lower part of the cold gas descending channel (8) and moves upward, and realizes countercurrent heat exchange with the high-temperature flue gas descending along the outer side of the delay isolation ring plate 10; the preheated gas enters the hot gas collecting box (14), and is supplied to the burner of the use device through the hot gas outlet (15).

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