CN116412682A - Multi-regenerator air preheater - Google Patents

Abstract

The invention discloses a multi-regenerator air preheater. The device comprises a shell, a sliding block and an executing mechanism, wherein N (N is an even number greater than or equal to 4) regenerators are contained in the sliding block, a heat accumulator is arranged in the heat accumulator, the executing mechanism comprises a push-pull rod, and the executing mechanism pushes and pulls the sliding block to do intermittent reciprocating motion in the shell through the push-pull rod, so that the regenerators through which flue gas flows and the regenerators through which air flows can synchronously exchange at fixed time, and the purpose of exchanging heat between the flue gas and the air is achieved. The multi-regenerator air preheater disclosed by the invention is resistant to low-temperature dew point corrosion of flue gas, can be used as a medium-temperature air preheater and a low-temperature air preheater, can be connected in parallel or in series, can be arranged up and down or left and right in parallel or in series, and is more suitable for the smoke discharging working condition of a petrochemical flame heating furnace at the temperature of less than 90 ℃.

Description

Multi-regenerator air preheater

Technical Field

The invention relates to an air preheater, in particular to a multi-regenerator air preheater.

Background

In various heating furnaces in petrochemical industry, iron and steel industry, nonferrous metallurgy industry, thermal power generation industry and the like, an air preheater is widely adopted for recovering flue gas waste heat. The regenerative air preheater is one of a plurality of air preheaters, and is widely used in various kilns in the industries of power station boilers, steel, nonferrous metallurgy and the like.

The heat accumulating type air preheater in the prior art has wide application mainly in two forms: rotary and valve switching.

The utility boiler widely adopts a rotary air preheater, the rotary air preheater transfers heat in a heat storage mode, and flue gas and air alternately flow through a heating surface. When the smoke flows, heat is transferred from the smoke to the heating surface, the temperature of the heating surface is increased, and the heat is accumulated; when air flows through again, the heating surface gives up the accumulated heat to the air. The rotary air preheater adopted by the power station boiler is used for recovering medium-temperature waste heat of flue gas, the inlet temperature of the flue gas is generally below 350 ℃, air and flue gas exchange heat in a centralized way in a single air preheater, the single preheater has a large volume, and the temperature of preheated combustion air is generally lower than 300 ℃. The burner burns with obvious flame shape, which belongs to the traditional flame burning.

Various kilns in industries such as iron and steel, nonferrous metallurgy and the like widely adopt valve switching type air preheaters, heat a heat accumulator by using high-temperature flue gas at about 1100 ℃, then heat the air by using heat stored in the heat accumulator, so that the air obtains high temperature of about 1000 ℃, and after the heat accumulator is cooled, the air is switched to a high-temperature flue gas heating state and is circularly reciprocated, thereby achieving the purpose of heat exchange. The valve switching type air preheater adopted in industries such as iron and steel, nonferrous metallurgy and the like is used for recovering high-temperature waste heat of flue gas, the preheater and the burner are arranged in pairs, the flue gas and air are dispersed in a plurality of preheaters for heat exchange, the volume of a single preheater is small, and the temperature of preheated combustion air is up to 1000 ℃. The burner burns without obvious flame shape, which belongs to oxygen-deficient diffuse combustion.

Chinese patent CN 104100993A discloses a reciprocating air preheater, wherein two heat exchange chambers filled with heat storages reciprocate to complete heat exchange, and the two heat exchange chambers form two channels: a flue gas channel and an air channel, the stroke of the driving device is about the width of a heat exchange chamber. The air preheater is matched with the burner in the regenerative heating furnace controlled by the disperse reversing, can continuously output high-temperature combustion air with stable pressure and small temperature fluctuation, and does not need to be switched between the combustion state and the smoke discharging state, so that the working continuity of the burner can be effectively ensured. Because of the dispersed reversing control, the smoke volume of a single nozzle is small, the volume of the preheater is small, and one smoke channel completely meets the requirement. If the flue gas and air exchange heat in a concentrated way, the flue gas completely enters the air preheater with only one flue gas channel, and because the flue gas quantity is very large, a larger heat exchange chamber is needed, the width of the heat exchange chamber can reach more than 3m, so that the stroke of a driving device is required to reach more than 3m, and the occupied space of the driving device is very large.

The petrochemical flame heating furnace is a heating furnace which runs for a long period, the working period is as long as 4 to 5 years, the air preheater is used for recovering low-temperature waste heat in flue gas below 350 ℃, air and flue gas are subjected to concentrated heat exchange, the burner burns with obvious flame shape, the petrochemical flame heating furnace belongs to the traditional flame burning, the heat accumulating type high-temperature air burning technology is not suitable for the furnace type, and the heat accumulating type air preheater matched with the burner is not suitable for use. At present, the common air preheaters of petrochemical flame heating furnaces are cast iron plate fin type air preheaters, plate type air preheaters, tube bundle type air preheaters, heat pipe type air preheaters and the like, and heat accumulating type air preheaters are rarely adopted and are in a test exploration stage, and no ideal heat accumulating type air preheaters are available for selection. At present, the fuel efficiency of the petrochemical flame heating furnace is generally about 92%, the exhaust temperature is about 130 ℃, and an air preheater of a metal material is often invalid due to low-temperature dew point corrosion of the exhaust gas, so that the long-period safe operation of the device is threatened. In addition, the problem of low-temperature dew point corrosion of the flue gas also prevents the continuous reduction of the flue gas temperature of the petrochemical flame heating furnace and the further improvement of the efficiency of the heating furnace.

Disclosure of Invention

According to the background technology, the invention aims to provide a novel heat accumulating type air preheater for the petrochemical flame heating furnace, solve the problem of low-temperature dew point corrosion of flue gas of the air preheater commonly used at present, and solve the problem of large-scale heat accumulating type air preheater.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

a multi-regenerator air preheater is characterized in that: the air preheater comprises a shell, a sliding block and an executing mechanism, wherein the sliding block is arranged in the shell, and the executing mechanism is arranged outside the shell. The actuating mechanism comprises a push-pull rod, the actuating mechanism pushes and pulls a sliding block to intermittently reciprocate in a shell through the push-pull rod, the stroke of the actuating mechanism is A, N (N is an even number greater than or equal to 4) heat storage chambers are arranged in the middle of the sliding block, two ends of each heat storage chamber are opened on two side wall plates of the sliding block, the opening sizes of the two side wall plates of the sliding block are equal and concentric, the center distance of the openings is A, the two ends of the side wall plates of the sliding block are left sealing sections and right sealing sections, the left sealing sections and the right sealing sections can seal interfaces at the left end and the right end of the shell, the shell body is cuboid and horizontally arranged, the upper surface and the lower surface of the shell are sealed, the two side wall plates of the shell are respectively provided with N+1 openings, the two side surface openings of the shell are equal and concentric with the opening sizes of the sliding block wall plates, the opening areas of the two side wall plates of the shell are equal or slightly greater, the center distance of the opening of the side surface of the shell is A, and the movable space of the shell inside is used for allowing the sliding block to intermittently reciprocate to move, so that the opening of the sliding block is in butt joint with the interface reciprocating ports of the shell.

The preferred range of the number N of the regenerators is an even number of 4 to 100, and the preferred range is 4, 6 or 8.

The invention relates to a multi-regenerator air preheater, which is further technically characterized in that: and a partition plate is arranged between the two adjacent regenerators. The heat storage chambers can be provided with a partition plate, and the heat storage chambers are not obviously divided to form a large heat storage chamber.

The invention relates to a multi-regenerator air preheater, which is further technically characterized in that: the air interfaces and the smoke interfaces of the shell interfaces are alternately arranged, and the air interfaces are arranged on two sides of each smoke interface.

The invention relates to a multi-regenerator air preheater, which is further technically characterized in that: the actuator travel a ranges from 50mm to 5000mm, preferably from 200mm to 2000mm.

The invention relates to a multi-regenerator air preheater, which is further technically characterized in that: and a sealing ring is arranged between the shell interface and the opening of the sliding block for sealing, and the sealing ring is provided with a spring for providing elasticity.

The invention relates to a multi-regenerator air preheater, which is further technically characterized in that: between the slide and the housing is a rolling bearing, preferably a rail, rail wheel, needle roller or flat cage assembly.

The multi-regenerator air preheater provided by the invention can be connected with a plurality of regenerators in parallel, or can be connected with a plurality of regenerators in series, and the regenerators can be arranged up and down or left and right in parallel or in series, and a plurality of execution mechanisms can perform sequential actions. The heat accumulator is typically preferably a honeycomb ceramic.

The invention relates to a multi-regenerator air preheater, which is further technically characterized in that: the regenerator is made of metal material, nonmetal material or composite material which can resist the low temperature dew point corrosion of the flue gas under the condition that the temperature of the flue gas inlet is lower than 200 ℃, and polytetrafluoroethylene and glass fiber reinforced plastic are preferred. Integral external insulation may be employed.

The invention relates to a multi-regenerator air preheater, which is further technically characterized in that: the heat exchange mode of the multi-regenerator air preheater is as follows:

the invention relates to a multi-regenerator air preheater, wherein the number of regenerators is N, the number of interfaces at each side of a shell is N+1, N is an even number greater than or equal to 4, and the number of smoke logistics interfaces is an even number interface, which is N/2; the air stream interfaces are odd-numbered interfaces, and 1+N/2 in total. The sliding block is pushed and pulled by the executing mechanism to do intermittent linear reciprocating motion, so that the channels of the smoke material flow and the air material flow are exchanged in the N heat accumulating chambers, and heat exchange is completed.

1) When the sliding block moves to the left end of the shell to be static, the opening at the leftmost end of the sliding block is in butt joint with the shell interface at the leftmost end of the shell to form N channels, and the opening at the rightmost end of the shell is sealed by the right sealing section of the side wall plate of the sliding block to block air from flowing. At the moment, the flue gas flows through even-numbered heat storage chambers (N/2 in total) to release heat to the heat storage bodies in the even-numbered heat storage chambers; the air flow flows through the odd-numbered regenerators (N/2 in total) and absorbs heat from the regenerators in the odd-numbered regenerators;

2) In the rightward movement process of the sliding block, the opening of the sliding block is staggered with the shell interface, the area, communicated with the left-most shell opening, of the opening of the sliding block at the leftmost side is smaller and smaller, the flue gas and air of the regenerator in the middle of the sliding block are replaced gradually, and the area, communicated with the right-most shell opening, of the opening of the sliding block at the rightmost side is larger and larger. In the compartment-by-compartment replacement process of the flue gas channels and the air channels in the regenerator, due to the volume effect, the flue gas reserved in the compartments is carried out by the entering air, the oxygen content of the air is reduced, and the low-oxygen air from the air channels is gathered together, so that the air and the carried flue gas are mixed in a disturbance manner, and the carried flue gas cannot form a flue gas cluster;

3) When the sliding block moves to the right end of the shell to be static, the opening at the rightmost end of the sliding block is in butt joint with the shell interface at the rightmost end of the shell to form N channels, and the opening at the leftmost end of the shell is sealed by the left sealing section of the side wall plate of the sliding block to block air from flowing. At the moment, the flue gas flows through the odd-numbered regenerators (N/2 in total) to release heat to the regenerators in the odd-numbered regenerators; the air flow flows through the even-numbered regenerators (N/2 in total) and absorbs heat from the regenerators in the even-numbered regenerators;

4) In the process of moving the sliding block leftwards, the flue gas and air in the regenerator are gradually replaced, and the process is the same as the reverse direction of the movement in the step 2).

The above-mentioned process is circulated reciprocally, realizes the heat exchange of flue gas stream and air stream.

Compared with the prior art, the invention has the beneficial effects that:

1) The multi-regenerator air preheater is matched with a burner in a regenerative kiln controlled by scattered reversing, and has simpler structure, more convenient operation and lower cost on the premise of the same fuel efficiency of the kiln compared with the regenerative air preheater adopting a three-way reversing valve and a four-way reversing valve; when the multi-regenerator air preheater works, combustion air and smoke with stable pressure can be continuously and uninterruptedly output, the effects on the hearth pressure and the burner combustion air pressure are almost avoided, and the problems of instant flow interruption of smoke flow and air flow during reversing of the three-way reversing valve and the four-way reversing valve, furnace hearth pressure fluctuation, burner combustion air pressure fluctuation and the like do not exist. The multi-regenerator air preheater is used in a regenerative kiln with concentrated heat exchange of flue gas and air, and the flue gas flows out from one outlet of a hearth and enters the preheater.

2) Compared with the air preheater disclosed by the patent CN 104100993A, the multi-regenerator air preheater disclosed by the invention has the advantages that under the condition of the same heat accumulator filling quantity, the stroke of the driving device can be shortened by 1/2, and the occupied space of the driving device is smaller; in the case of consistent stroke of the drive device, the amount of air and smoke passing through can be increased by a factor of N/2 (N is an even number greater than or equal to 4). The multi-regenerator air preheater is more suitable for occasions where high-flow flue gas and air exchange heat intensively. In addition, the air flows out of the plurality of regenerators and is mixed, so that the turbulence effect on the smoke which is retained by the volume effect and forms a smoke cluster is better.

3) Compared with common metal cast iron plate fin type, plate type, tube type, heat pipe type and other air preheaters for petrochemical flame heating furnace, the present invention has honeycomb ceramic as heat accumulator and no low temperature dew point corrosion of fume. When the temperature of the flue gas inlet is lower than 200 ℃, the regenerator provided by the invention can be made of metal materials such as 2205 and nonmetal materials such as polytetrafluoroethylene or glass fiber reinforced plastics which are resistant to low-temperature dew point corrosion of the flue gas, and the regenerator is also resistant to corrosion. Therefore, the multi-regenerator air preheater has stronger corrosion resistance and longer service life. The invention is adopted singly or used as a low-temperature air preheater to be matched with other forms of air preheaters, so that the exhaust gas temperature of the petrochemical flame heating furnace can be reduced to below 90 ℃ and the fuel efficiency can be improved to above 95%.

4) Compared with common cross-flow cast iron plate fin type, plate type, tube bundle type and other air preheaters, the multi-regenerator air preheater provided by the invention has the advantages that the temperature difference of the hot end is smaller due to the pure countercurrent heat exchange of smoke and air, and the temperature of the preheated air is more beneficial to being improved.

5) Compared with the common modularized cast iron plate fin type, plate type and other air preheaters, the multi-regenerator air preheater provided by the invention has the advantages of higher standardization degree, better modularization effect, simpler and more flexible arrangement. The air preheater can be connected in parallel or in series, and the parallel or series connection can be overlapped up and down or left and right, so that various middle-sized and large-sized air preheaters are formed for selection.

The present invention will be described in detail below with reference to the drawings and the detailed description, which do not limit the scope of the invention.

Drawings

FIG. 1 is a schematic diagram of a multiple regenerator air preheater of the present invention (slider at left end);

FIG. 2 is a schematic diagram of a multiple regenerator air preheater of the present invention (slider at right end);

FIG. 3 is a schematic illustration of a multi-regenerator air preheater housing (southeast isometric view) according to the present invention;

FIG. 4 is a schematic illustration of a multi-regenerator air preheater housing (northeast isometric view) according to the present invention;

FIG. 5 is a schematic illustration of a multi-regenerator air preheater slide (southeast isometric view) in accordance with the present invention;

FIG. 6 is a schematic illustration of a multi-regenerator air preheater slide (northeast isometric view) in accordance with the present invention;

FIG. 7 is a multi-regenerator air preheater slide (southeast isometric view, cross-sectional view) of the present invention;

FIG. 8 is a multi-regenerator air preheater of the present invention (slider at left end, cross-section);

FIG. 9 is a multi-regenerator air preheater of the present invention (slider at right end, cross-section);

FIG. 10 is a schematic diagram of the application of a multi-regenerator air preheater of the present invention in a petrochemical flame heating furnace waste heat recovery system;

fig. 11 is a diagram illustrating an operation of a multi-regenerative air preheater according to the present invention.

The reference numerals shown in the figures are:

100. a multi-regenerator air preheater;

1. a channel; 2. A channel; 3. a channel; 4. a channel; 5. a channel;

10. a housing;

10-1, a shell interface; 10-2, a shell interface; 10-3, a shell interface;

10-4, a shell interface; 10-5, a shell interface; 10-6, a shell interface;

10-7, a shell interface; 10-8, a shell interface; 10-9, a shell interface;

10-10, a shell interface;

11. a housing frame;

12. wall plates on two sides of the shell; 13. a housing upper and lower wall plate; 14. wall plates at two ends of the shell;

15. a seal ring; 16. a seal ring seat; 17. a spring and guide post assembly;

18. a track; 19. external flange of shell

20. A slide block;

21. a regenerator; 20-1, import and export; 20-5, import and export;

22. a regenerator; 20-2, import and export; 20-6, import and export;

23. a regenerator; 20-3, import and export; 20-7, import and export;

24. a regenerator; 20-4, import and export; 20-8, import and export;

25. a left seal section; 26. a right seal section; 27. a heat storage body;

28. wall plates on two sides of the sliding block; 29. sliding block frame

30. An actuator; 31. a push-pull rod; 32. a push-pull rod connecting seat;

40. a grille; 41. a rail wheel; 42. a partition plate;

50. petrochemical flame heating furnace;

51. a burner; 52. a furnace top flue gas outlet; 53. an induced draft fan; 54. a floor chimney;

55. a blower;

60. a two-stage air preheater.

Detailed Description

The invention will be described in more detail below with reference to the accompanying drawings. While the preferred embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

The present embodiment is described with n=4 and the actuator stroke a=1m.

As shown in fig. 1 to 9, a multi-regenerator air preheater 100 of the present invention is mainly composed of a housing 10, a slider 20 and an actuator 30. The housing 10 is rectangular parallelepiped and horizontally arranged. The actuator 30 is a straight travel actuator, and is mounted at the right end of the housing 10, the travel is 1m, and the actuator 30 pushes and pulls the slider 20 through the push-pull rod 31. The slide block 20 comprises 4 regenerators, namely regenerators 21, 22, 23 and 24, the center distance of the regenerators is 1m, the slide block 20 also comprises a left sealing section 25 and a right sealing section 26, the slide block 20 is arranged in the shell 10, and the regenerators 21, 22, 23 and 24 are respectively filled with the regenerators 27. The sealing ring 15 is arranged between the interface of the shell 10 and the sliding block 20, so that the opening of the sliding block 20 is completely sealed with the interface of the shell 10. The two sides of the shell 10 are respectively provided with 5 interfaces, the center distance of the interfaces is also 1m, 5 channels are formed by matching the interfaces with the sliding block 10, and the channels are respectively 1, 2, 3, 4 and 5. As shown in fig. 1 and 2, the channels 1, 3 and 5 are air channels, the channels 2 and 4 are flue gas channels, and the flue gas stream (1) and the air stream (2) perform heat exchange in the 5 channels.

As shown in fig. 3 and 4, the housing 10 of the present invention is mainly composed of a housing frame 11, housing side wall plates 12, housing upper and lower wall plates 13, and housing end wall plates 14. The sealing ring seat 16 is fixed on the inner sides of the wall plates 12 on two sides of the shell, the sealing ring 15 is installed in the sealing ring seat 16, and the spring and guide post assembly 17 elastically supports the sealing ring 15, so that the sealing ring 15 is tightly buckled on the surface of the sliding block 20. The two side wall plates 12 of the shell are provided with 5 openings, and in fig. 3, the shell openings 10-1, 10-2, 10-3, 10-4 and 10-5 are visible, and the center distance of the shell openings 10-1, 10-2, 10-3, 10-4 and 10-5 is 1m. The housing openings 10-6, 10-7, 10-8, 10-9, 10-10 are visible in fig. 4. The housing opening 10-1 is concentric with the housing opening 10-6, the housing opening 10-2 is concentric with the housing opening 10-7, the housing opening 10-3 is concentric with the housing opening 10-8, the housing opening 10-4 is concentric with the housing opening 10-9, and the housing opening 10-5 is concentric with the housing opening 10-10. The outer sides of the 10 shell openings are connected with a shell external flange 19, and sealing rings 15 and sealing ring seats 16 are arranged on the inner sides of the 10 shell openings. The rail 18 is positioned at the bottom of the housing 10 and supports rail wheels 41.

The slide block 20 of the invention mainly comprises heat storage chambers 21, 22, 23, 24, a left sealing section 25, a right sealing section 26, a heat storage body 27, two side wall plates 28 of the slide block and a slide block frame 29. In FIG. 5, the regenerators are regenerators 21, 22, 23, 24 in sequence from left to right. Four regenerator inlets and outlets are respectively arranged on the wall plates 28 on two sides of the sliding block, the 8 inlets and outlets are the same grid 40 openings, and in FIG. 5, the inlet and outlet 20-1 of the regenerator 21, the inlet and outlet 20-2 of the regenerator 22, the inlet and outlet 20-3 of the regenerator 23 and the inlet and outlet 20-4 of the regenerator 24 are visible. In FIG. 6, the regenerator 21 ports 20-5, the regenerator 22 ports 20-6, the regenerator 23 ports 20-7, and the regenerator 24 ports 20-8 are seen. Inlet 20-1 is concentric with inlet 20-5, inlet 20-2 is concentric with inlet 20-6, inlet 20-3 is concentric with inlet 20-7, and inlet 20-4 is concentric with inlet 20-8. The center distances of the inlets and outlets 20-1, 20-2, 20-3 and 20-4 are 1m. The center of the end part of the sliding block frame 29 is provided with a push-pull rod connecting seat 32, and the push-pull rod connecting seat 32 is connected with the push-pull rod 31.

The two side wall plates 28 of the sliding block are flat plates, and the grating 40 on the flat plates is formed by hollowing. The bottom of the slider frame 29 is provided with rail wheels 41, and the rail wheels 41 roll on the rails 18 to minimize friction during intermittent reciprocation of the slider 40 within the housing 10. The regenerators 21, 22, 23, 24 are separated by a partition 42, and adjacent regenerators 42 are spaced apart. The regenerators 21, 22, 23, 24 are filled with regenerators 27.

When the actuator 30 pushes the slider 20 to rest at the left end of the housing 10 through the push- pull rod 31, 10 housing interfaces of the housing 10 are in butt joint with 8 inlets and outlets of the regenerators 21, 22, 23, 24 in the slider 20 and the right seal segment 26, as follows: 10-1 … 20-1 … regenerator 21 … 20-5 … 10-6 butt joint forms passageway 1, 10-2 … 20-2 … regenerator 22 … 20-6 … 10-7 butt joint forms passageway 2, 10-3 … 20-3 … regenerator 23 … 20-7 … 10-8 butt joint forms passageway 3, 10-4 … 20-4 … regenerator 24 … 20-8 … 10-9 butt joint forms passageway 4, 10-5 … right seal section 26 … -10 butt joint forms passageway 5, passageways 1, 2, 3, 4 are clear, passageway 5 is blocked by right seal section 26 of the slider. At this time, the flue gas stream (1) flows through the even number heat storage chambers 22 and 24 through the channels 2 and 4, and releases heat to the heat storages 27 in the even number heat storage chambers 22 and 24; the air stream (2) flows through the odd regenerators 21, 23 via channels 1, 3, absorbing heat from the regenerators 27 in the odd regenerators 21, 23.

As shown in fig. 8 and 9, during the process that the actuator 30 pulls the slider 20 from the left end to the right end (from fig. 8 to 9) of the housing 10 through the push-pull rod 31, the left seal section 25 moves rightward, the regenerator opening of the slider 20 moves rightward, the area where the leftmost regenerator 21 opening of the slider 20 communicates with the leftmost housing opening is smaller, and the flow area of the channel 1 is smaller. The right seal segment 26 moves to the right, the area of the opening of the right-most regenerator 24 of the slide block communicated with the opening of the right-most shell is larger and larger, and the flow area of the channel 5 is larger and larger. The slide regenerators 21, 22, 23, 24 are progressively replaced with flue gas and air. The smoke channels 2 and 4 are always unblocked, so that the influence of the movement of the sliding block 20 on the flow of the smoke stream (1) is small, and the fluctuation of the pressure drop of the smoke in the sliding block 20 is small; the air passage 3 is always smooth, the closing area of the air passage 1 and the opening area of the air passage 5 are synchronously exchanged, so that the influence of the movement of the slide 20 on the flow of the air stream (2) is small, and the fluctuation of the pressure drop of the air in the slide 20 is also small. In the gradual replacement process of the flue gas and air in the regenerators 21, 22, 23 and 24, the retained flue gas in the regenerators 22 and 24 is carried out by the entered air due to the volume effect, the oxygen content of the air is reduced, the retained flue gas from the channels 3 and 5 is summarized to the total air duct and mixed with the turbulent flow of the air in the total air duct, so that the carried retained flue gas can not form a flue gas group, and the combustion influence on the burner is small. The air retained in the regenerators 21 and 23 is carried out by the entered smoke, the oxygen content of the smoke is increased, the retained air from the channels 2 and 4 is gathered to the main flue and mixed with the turbulent flow of the smoke in the main flue, so that the carried air can not form air clusters, and the environmental protection monitoring influence on the oxygen content of the smoke is minimized.

As shown in fig. 9, when the actuator 30 pulls the slider 20 to the right end of the housing 10 by the push-pull rod 31 for rest, 10 housing interfaces of the housing 10 are in butt joint with 8 ports and left seal segments 25 of the regenerators 21, 22, 23, 24 in the slider 20, as follows: 10-1 … left seal section 25 … -6 butt joint forms passageway 1, 10-2 … 20-1 … regenerator 21 … -5 … 10-7 butt joint forms passageway 2, 10-3 … 20-2 … regenerator 22 … -6 … 10-8 butt joint forms passageway 3, 10-4 … 20-3 … regenerator 23 … 20-7 … 10-9 butt joint forms passageway 4, 10-5 … 20-4 … regenerator 24 … 20-8 … 10-10 butt joint forms passageway 5, passageways 2, 3, 4, 5 are clear, passageway 1 is blocked by left seal section 25 of the slider. At this time, the flue gas stream (1) flows through the odd-numbered regenerators 21, 23 through the channels 2, 4 to release heat to the regenerators 27 in the odd-numbered regenerators 21, 23; the air stream (2) flows through the even regenerators 22, 24 via channels 3, 5, absorbing heat from the regenerators 27 within the even regenerators 22, 24.

As shown in fig. 9 and 8, during the movement of the actuator 30 pushing the slider 20 from the right end to the left end (from fig. 9 to 8) through the push-pull rod 31, the right seal segment 26 moves to the left, the regenerator opening of the slider 20 moves to the left, the area of the opening of the right-most regenerator 24 of the slider 20 communicating with the right-most housing opening becomes smaller, and the flow area of the channel 5 becomes smaller. The left seal section 25 moves leftwards, the area of the opening of the regenerator 21 at the leftmost side of the sliding block communicated with the opening of the shell at the rightmost end is larger and larger, and the flow area of the channel 1 is larger and larger. The slide regenerators 21, 22, 23, 24 are progressively replaced with flue gas and air. The smoke channels 2 and 4 are always unblocked, so that the influence of the movement of the sliding block 20 on the flow of the smoke stream (1) is small, and the fluctuation of the pressure drop of the smoke in the sliding block 20 is small; the air channel 3 is always smooth, the opening area of the air channel 1 and the closing area of the air channel 5 are synchronously exchanged, so that the influence of the movement of the sliding block 20 on the flow of the air stream (2) is small, and the fluctuation of the pressure drop of the air in the sliding block 20 is also small. In the gradual replacement process of the flue gas and air in the regenerators 21, 22, 23 and 24, the flue gas retained in the regenerators 21 and 23 is carried out by the entering air due to the volumetric effect, the oxygen content of the air is reduced, the retained flue gas from the channels 1 and 3 and the air from the channel 5 are gathered to the total air channel and are mixed with the turbulent flow of the air in the total air channel, so that the carried flue gas cannot form a flue gas group, and the combustion influence on the burner is small. The air retained in the regenerators 22 and 24 is carried out by the entered smoke, the oxygen content of the smoke is increased, the retained air from the channels 2 and 4 is gathered to the main flue and mixed with the turbulent flow of the smoke in the main flue, so that the carried air can not form air clusters, and the environmental protection monitoring influence on the oxygen content of the smoke is minimized.

The above-mentioned process is circulated reciprocally, has realized the heat exchange of flue gas stream (1) and air stream (2), and output stable flue gas stream (1) and air stream (2), the pressure drop fluctuation is very little.

The foregoing detailed description of the invention has been presented only to illustrate one embodiment of the invention and is not intended to limit the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Examples

The specific operation of the present invention as an air preheater will be described in more detail below with reference to the accompanying drawings.

Fig. 10 shows a petrochemical flame heating furnace 50 with a flue gas waste heat recovery system, which uses a two-stage air preheater to preheat air. The secondary air preheater 60 is a conventional plate air preheater and is arranged before the induced draft fan 53. A length of air preheater employing the multi-regenerator air preheater 100 of the present invention is disposed between the induced draft fan 53 and the floor stack 54. The multi-regenerator air preheater 100 of the present invention is disposed in the low temperature region of the flue gas because of its ability to withstand low temperature dew point corrosion of the flue gas. The temperature of the flue gas stream (1) at the top flue gas outlet 52 is 250 ℃ and the temperature at the inlet of the floor stack 54 is about 85 ℃.

The flow path of the flue gas stream (1) is as follows: after exiting from the furnace top flue gas outlet 52, the flue gas stream (1) at 250 ℃ enters the secondary air preheater 60 to release heat and cool to 150 ℃, then enters the multi-regenerator air preheater 100 of the invention through the induced draft fan 53, releases heat and cools to 80-90 ℃ in the multi-regenerator air preheater 100 of the invention, and finally is discharged into the floor chimney 54. The flue gas stream (1) enters the multi-regenerator air preheater 100 of the present invention at a temperature of 150 ℃ and exits the multi-regenerator air preheater 100 of the present invention at an average temperature of 85 ℃.

The air stream (2) flows through the following route: after the air flow (2) with the temperature of 20 ℃ comes out of the blower 55, the air flow enters the multi-regenerator air preheater 100 of the invention, absorbs heat and heats up in the multi-regenerator air preheater 100 of the invention, then enters the two-stage air preheater 60 to absorb heat and heat up continuously, and then enters the burner 51 at the bottom of the flame heating furnace 50 to support combustion. The temperature of the air stream (2) entering the multi-regenerator air preheater 100 of the present invention was 20 ℃, and the average temperature exiting the multi-regenerator air preheater 100 of the present invention was about 90 ℃.

The operation of the regenerative air preheater of the present invention will be described in detail below, assuming that the multi-regenerator air preheater slider 20 of the present invention controls the actuator operation on the condition that the operation time remains for 3min at one end of the housing 10.

Initially, in the first operating position, the slider 20 is at the left end of the housing 10, as shown in fig. 1 and 8

In operation, the slider 20 of the multi-regenerator air preheater 100 of the present invention resides at the left end of the housing 10 shown in FIG. 1 in an operating position one. The 150 ℃ flue gas stream (1) enters the regenerators 22, 24, releases heat to cool the regenerators 27 in the regenerators 22, 24, and initially the temperature of the flue gas stream (1) exiting the regenerators 22, 24 is at a minimum of about 80 ℃, and then gradually rises to about 90 ℃ over time. The air flow (2) at 20 ℃ enters the regenerators 21, 23, absorbs heat from the regenerators 27 in the regenerators 21, 23 and then rises in temperature. Initially, the air stream (2) exits the regenerators 21, 23 at a temperature of up to about 95 ℃, and then gradually decreases over time.

Then, to the second operating position, the slider 20 is at the right end of the housing 10, as shown in FIGS. 2 and 9

After the sliding block 20 of the multi-regenerator air preheater 100 of the present invention works for 3min at the first working position shown in fig. 1, the temperature of the flue gas stream (1) from the regenerators 22, 24 rises to about 90 ℃, the actuator 30 acts to pull the sliding block 20 to the right end of the housing 10, and the sliding block stays at the second working position shown in fig. 2. The 150 ℃ flue gas stream (1) enters the regenerators 21, 23, releases heat to cool the regenerators 21, 23, and initially the temperature of the flue gas stream (1) exiting the regenerators 21, 23 is at least about 80 ℃, and then gradually rises to about 90 ℃ over time. The air flow (2) at 20 ℃ enters the regenerators 22, 24, absorbs heat from the regenerators 27 in the regenerators 22, 24 and then heats up. Initially, the air stream (2) exits the regenerators 22, 24 at a temperature of up to about 95 ℃, and then gradually decreases over time.

After that, the working position is returned to the first working position, and the next circulation process is started

After the sliding block 20 of the multi-regenerator air preheater 100 of the present invention works at the second working position shown in fig. 1 for 3min, the temperature of the flue gas stream (1) at 180 ℃ rises to about 90 ℃, the actuator 30 acts to push the sliding block 20 to the left end of the housing 10, and the sliding block returns to the first working position shown in fig. 1, and the above step 1 is repeated to restart the next cycle process.

The above processes are repeated, and the flue gas stream (1) and the air stream (2) are subjected to continuous heat exchange. The exhaust gas temperature of the multi-regenerator air preheater 100 of the present invention is not constant, but is varied, in the above embodiment, throughout the exhaust gas temperature cycle between 80 deg.c and 90 deg.c, with an average exhaust gas temperature of 85 deg.c.

The above-described operation from 1 to 3 can be represented by a cyclic process, as shown in fig. 11.

The process shown in fig. 11 controls the operation of the actuator 30 on the condition that the slider 20 stays at one end of the housing 10 for 3min, but may control the operation of the actuator 30 on the condition that the exhaust gas temperature reaches a certain value (for example, 90 ℃), and will not be described in detail.

The above examples illustrate only one embodiment of the invention, which is described in more detail and is not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims (14)

1. A multi-regenerator air preheater is characterized in that: the air preheater comprises a shell, a sliding block and an actuating mechanism, wherein the sliding block is arranged in the shell, the actuating mechanism is arranged outside the shell and comprises a push-pull rod, the actuating mechanism pushes and pulls the sliding block through the push-pull rod to perform intermittent reciprocating motion in the shell, the stroke of the actuating mechanism is A, N regenerators are arranged in the middle of the sliding block, a regenerator is arranged in the regenerator, N is an even number greater than or equal to 4, openings at two ends of each regenerator are arranged on two side wall plates of the sliding block, the openings of the two side wall plates of the sliding block are equal in size and concentric, the center distance of the openings is A, the two ends of the side wall plates of the sliding block are provided with a left sealing section and a right sealing section, the left sealing section or the right sealing section can seal an interface at the left end or right end of the shell, the shell body is a cuboid and is horizontally arranged, N+1 openings are respectively arranged on the two side wall plates of the shell, the openings at two sides of the shell are equal in size and concentric with the opening of the sliding block, the opening is equal to or slightly larger in area, the center distance of the opening of the side wall plate of the shell is A, and the opening of the sliding block is allowed to reciprocate the opening of the sliding block to reciprocate.

2. The multi-regenerator air preheater of claim 1, wherein: the number N of the regenerators is an even number of 4-100.

3. A multiple regenerator air preheater according to claim 1 or 3, in which: the number N of the regenerators is 4, 6 or 8.

4. The multi-regenerator air preheater of claim 1, wherein: and a partition plate is arranged between the two adjacent regenerators.

5. The multi-regenerator air preheater of claim 1, wherein: and a partition plate is arranged in each heat storage chamber.

6. The multi-regenerator air preheater of claim 1, wherein: the air interfaces and the smoke interfaces of the shell interfaces are alternately arranged, and the air interfaces are arranged on two sides of each smoke interface.

7. The multi-regenerator air preheater of claim 1, wherein: the actuator travel A ranges from 50mm to 5000mm.

8. The multiple regenerator air preheater according to claim 1 or 7, wherein: the actuator travel A ranges from 200mm to 2000mm.

9. The multi-regenerator air preheater of claim 1, wherein: a sealing ring is arranged between the shell interface and the opening of the sliding block for sealing, and the sealing ring is provided with a spring for providing elasticity.

10. The multi-regenerator air preheater of claim 1, wherein: and a rolling bearing is arranged between the sliding block and the shell.

11. The multiple regenerator air preheater according to claim 1 or 10, wherein: and a track, a track wheel, a rolling needle or a flat retainer component is arranged between the sliding block and the shell.

12. The multi-regenerator air preheater of claim 1, wherein: the heat accumulator is honeycomb ceramics.

13. The multi-regenerator air preheater of claim 1, wherein: and under the condition that the temperature of the flue gas inlet is lower than 200 ℃, the heat storage chamber is made of a metal material, a nonmetal material or a composite material which is resistant to low-temperature dew point corrosion of the flue gas.

14. The multi-regenerator air preheater of claim 1, wherein: the heat exchange mode of the multi-regenerator air preheater is as follows:

the number of interfaces at each side of the shell is N+1, N is an even number which is more than or equal to 4, and the number of smoke logistics interfaces is an even number interface, which is N/2; the air logistics interfaces are odd interfaces, 1+N/2 in number, and the sliding blocks do intermittent linear reciprocating motion under the pushing and pulling of the executing mechanism, so that the exchange of the flue gas logistics and the air logistics in N heat accumulating chambers is realized;

1) When the sliding block is positioned at the left end of the shell, the opening at the leftmost end of the sliding block is in butt joint with the shell interface at the leftmost end of the shell to form N channels, the opening at the rightmost end of the sliding block is sealed by the right sealing section of the side wall plate of the sliding block to block air from flowing, at the moment, smoke flows flow through even-numbered heat storage chambers, N/2 of the smoke flows are heated by heat storage bodies in the even-numbered heat storage chambers; the air flow flows through the odd-numbered heat storage chambers, and N/2 air flows are used for absorbing heat from the heat storages in the odd-numbered heat storage chambers;

2) When the sliding block is positioned at the right end of the shell, the opening at the rightmost end of the sliding block is in butt joint with the shell interface at the rightmost end of the shell to form N channels, the opening at the leftmost end of the sliding block is sealed by the left sealing section of the side wall plate of the sliding block to block air from flowing, and at the moment, smoke flows flow through the odd-numbered heat storage chambers, and N/2 of smoke flows heat the heat storage bodies in the odd-numbered heat storage chambers; the air flow flows through the even-number heat storage chambers, and N/2 of the air flows absorb heat from the heat storages in the even-number heat storage chambers;

the process is circularly and reciprocally carried out, and the flue gas stream and the air stream are continuously exchanged in the channels of the N heat storage chambers, so that the flue gas stream and the air stream can be subjected to continuous heat exchange in the multi-heat storage chamber air preheater.

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