Rotary air pre-heater ring-dividing heating system based on air heater zone management

Abstract

The utility model discloses a rotary air pre-heater ring-dividing temperature rising system based on air heater zone management. The rotary air pre-heater ring-dividing temperature rising system comprises a rotor, a circumferential movable partition plate, a special-shaped static partition plate, a cold air inlet pipe and an air heater system. The circumferential movable partition plates are mounted on the lower end face of the rotor and divide the lower end face of the rotor into N concentric rings; the cold air inlet pipe is located below the lower end face of the rotor and at least covers one air branch bin. The special-shaped static partition plates are installed in the cold air inlet pipe, the cold air inlet pipe is divided into at least N independent ring-dividing air inlet pipes, and the ring-dividing air inlet pipes are located below the corresponding concentric rings. The air heater system comprises N partition air heaters, a heat source conveying pipe and N air heater partition air inlet valves, and the partition air heaters are installed in the corresponding branch ring air inlet pipes. One end of the heat source conveying pipe is connected with a heat source, the other end of the heat source conveying pipe is branched into N heat source branch pipes, the heat source branch pipes lead to the corresponding partition air heaters, and the air heater partition air inlet valves are installed on the corresponding heat source branch pipes. The device can solve the problems of blockage and corrosion.

Description

Technical Field

[0001] The utility model relates to a rotary air preheater ring heating system based on zone management of heaters, belonging to the technical field of blockage treatment of rotary air preheaters in coal-fired power plants. Background Art

[0002] The rotary air preheater used in the field of coal-fired power generation is generally a two-compartment, three-compartment or four-compartment structure, including air compartments (primary air compartments, secondary air compartments) and flue gas compartments, which use the heat of high-temperature flue gas to heat the air, thereby realizing energy recovery. However, after the flue gas temperature drops, SO3 in the flue gas reacts with NH3 escaped from upstream denitrification to form ammonium bisulfate (NH4HSO4), which is liquid in the range of 146-207°C and adheres to the surface of the thermal storage element together with the coal fly ash; when the temperature drops further, SO3 also reacts with water vapor in the flue gas to form liquid sulfuric acid (H2SO4), causing low-temperature corrosion, further aggravating the blockage and corrosion problems of the thermal storage element.

[0003] Chinese Patent 202122061569.7 discloses a rotary air preheater anti-blocking system based on ring-by-ring heating. The air preheater rotor is divided into multiple concentric rings. The cold air volume of each concentric ring can be independently adjusted through the ring-by-ring regulating door. When the cold air volume of one of the rings is reduced, the exhaust temperature of the flue gas side of the corresponding ring rises, and the wall temperature of the heat storage element of the ring increases, gasifying to form acid liquid that blocks ash, and regularly loosens the accumulated ash. In actual use of the above system, since the amount of air required by the coal-fired power generation boiler during the ring-by-ring heating period does not change much relative to the amount of air during the non-ring heating period, when the air volume of the heating ring decreases, the air volume of the non-heating ring must be increased. At this time, the exhaust temperature of the corresponding non-heating ring will decrease, which to a certain extent aggravates the local corrosion and ash blocking problems of the air preheater in a short period of time. Utility Model Content

[0004] In order to solve the problem in the prior art that the exhaust gas temperature of the non-heating ring is too low during the heating period of the rotary air preheater, the utility model provides a rotary air preheater heating system based on heater zone management.

[0005] In order to solve the above technical problems, the technical solutions adopted by the present utility model are as follows:

[0006] A rotary air preheater ring heating system based on heater zone management, comprising a rotor, a circumferential moving baffle, a special-shaped static baffle, a cold air inlet pipe and a heater system;

[0007] The circumferential moving partition is installed on the lower end surface of the rotor, dividing the lower end surface of the rotor into N concentric rings, N ≥ 2;

[0008] The cold air inlet pipe is located below the lower end surface of the rotor and covers at least one air compartment;

[0009] The special-shaped static baffle is installed in the cold air inlet duct, dividing the cold air inlet duct into at least N independent sub-ring air inlet ducts, the N sub-ring air inlet ducts correspond to the N concentric rings one by one, and the sub-ring air inlet ducts are located below the corresponding concentric rings;

[0010] The heater system includes at least N zone heaters, a heat source delivery pipe, N heat source branch pipes and N zone steam inlet valves of the heater. The N zone heaters correspond one-to-one to the N sub-ring air inlet pipes, and the zone heaters are installed in the corresponding sub-ring air inlet pipes; one end of the heat source delivery pipe is connected to the heat source, and the other end is divided into N heat source branch pipes. The N heat source branch pipes, N zone heaters and N zone steam inlet valves of the heater correspond one-to-one, the heat source branch pipes lead to the corresponding zone heaters, and the heater zone steam inlet valves are installed on the corresponding heat source branch pipes.

[0011] As common sense, the rotary air preheater has a multi-compartment structure (two-compartment, three-compartment or four-compartment, etc.), including at least one flue gas compartment and one air compartment (such as a primary air compartment, a secondary air compartment, etc.).

[0012] When the above system is in operation, a heat source can be provided to the heater system, and heat can be transported to the corresponding zone heater through the heat source branch pipe to increase the temperature of the air in the corresponding concentric rings. In this way, when the flue gas in the corresponding concentric rings exchanges energy with the air, the heat loss of the flue gas will be reduced and the temperature will be increased, thereby increasing the wall temperature of the heat storage element in the corresponding concentric ring, and the condensed or crystallized materials adhering thereto will gradually vaporize and be discharged from the rotary air preheater rotor along with the hot flue gas, thereby effectively solving (reducing or avoiding) the blockage and corrosion problems of the rotary air preheater.

[0013] When the system of the present application is used to prevent blockage, there is no need to reduce the air volume of the heating ring, and thus the air volume of other rings (non-heating rings) will not change due to the heating of a certain ring, which effectively solves the problem of local corrosion and ash blockage caused by the change of the air volume of the non-heating ring.

[0014] The air input by the blower reaches the cold air inlet pipe (existing technology) through the secondary air inlet duct and enters different sub-ring inlet pipes respectively.

[0015] The above-mentioned heater zone steam inlet valve is located outside the air preheater.

[0016] The above heat source is preferably a steam generator, that is, steam is used as a heat source. The heater uses steam as a heat source, and phase change heat transfer can reduce the heat exchange surface. The heat source is divided into two paths, one is a high-temperature steam heat source, preferably the temperature of the high-temperature steam heat source is 120-200°C, which is used for regular dry burning to solve the problem of ammonium bisulfate deposition (generally dry burning once every 15-30 days); the other is a low-temperature steam heat source, preferably the temperature of the low-temperature steam heat source is 80-120°C, which is used for daily low-temperature corrosion prevention. The condensed water generated after the heater heat exchange can be connected to the condensate system on the steam turbine side.

[0017] As one of the preferred implementation schemes, the high-temperature steam source is transported through the high-temperature steam source pipe, and the low-temperature steam source is transported through the low-temperature steam source pipe. The high-temperature steam source pipe, the low-temperature steam source pipe and the heat source transport pipe are connected through a three-way valve. This is clever, simple and easy to control. By setting a valve, the problem of high and low temperature steam source transportation can be solved. Of course, other types of valve groups can also be used, such as setting valves on the high and low temperature steam source pipes respectively, or other forms.

[0018] In order to meet the needs of general working conditions, the value of N is preferably 2, 3 or 4.

[0019] The above-mentioned circumferential dynamic partition is installed on the lower end surface of the rotor, and preferably the lower end surface of the rotor is divided into N concentric rings of equal area.

[0020] The upper end face of the above-mentioned split-ring air inlet duct is a fan-shaped structure including two arcuate edges. The two arcuate edges of the split-ring air inlet duct are equal to the curvature of the circumferential dynamic partitions on both sides of the corresponding concentric rings and are opposite to each other up and down; the lower end face of the split-ring air inlet duct is a rectangle.

[0021] The above-mentioned "fan-shaped" refers to a figure surrounded by two arcuate edges with the same bending direction and two radial edges connecting the two ends of the two arcuate edges; the above-mentioned "rectangle" refers to a figure surrounded by the cold air inlet duct and the special-shaped static partition.

[0022] In order to improve the sealing performance, a sealing pair is provided between the divided-ring air inlet pipe and the circumferential dynamic partitions on both sides of the corresponding concentric ring.

[0023] In order to adapt to the on-site installation space requirements, the structure of the above-mentioned zone air heater needs to be determined according to its installation position in the split-ring air inlet duct, that is, when the zone air heater is located in the annular area of ​​the split-ring air inlet duct, its structure is fan-shaped; when the zone air heater is located in the rectangular area of ​​the split-ring air inlet duct, its structure is rectangular.

[0024] In order to further reduce the wind side system resistance when the system is not in operation, the rectangular partition heater may preferably be a rotary type.

[0025] The present application does not make any special improvements to the structure of the heater, so it will not be described in detail.

[0026] The technologies not mentioned in this utility model are all referred to the prior art.

[0027] The utility model discloses a rotary air preheater ring heating system based on heater zone management, which can provide a high-temperature steam heat source or a low-temperature steam heat source to the heater system, and transmit heat to the corresponding zone heater through the heat source branch pipe, so as to specifically increase the temperature of the air in the corresponding concentric rings, and then increase the wall temperature of the heat storage element in the corresponding concentric rings, so that the condensed or crystallized materials adhering to the heat storage element are gradually vaporized and discharged from the rotary air preheater rotor along with the heat medium, thereby effectively solving the blockage and corrosion problems of the rotary air preheater; the air volume of other rings (non-heating rings) will not change due to the heating of a certain ring, which effectively solves the problems of local corrosion and dust blockage caused by the change of the air volume of the non-heating ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the rotary air preheater ring heating system based on heater zoning management in Example 1 of the utility model (three compartments, N=2, rectangular zoned heater).

[0029] Figure 2 for Figure 1 Schematic diagram of the structure of the lower end surface of the middle rotor;

[0030] Figure 3 It is a structural schematic diagram of the rotary air preheater ring heating system based on heater zoning management in Example 2 of the utility model (three compartments, N=3, rectangular zoned heater).

[0031] Figure 4 for Figure 3 Schematic diagram of the structure of the lower end surface of the middle rotor;

[0032] Figure 5 It is a structural schematic diagram of the rotary air preheater ring heating system based on heater zoning management in Example 3 of the utility model (three compartments, N=2, fan-shaped zoned heater).

[0033] Figure 6 for Figure 5 Schematic diagram of the structure of the lower end surface of the middle rotor;

[0034] Figure 7 It is a structural schematic diagram of the rotary air preheater ring heating system based on heater zoning management in Example 4 of the utility model (three compartments, N=3, fan-shaped zoned heater).

[0035] Figure 8 for Figure 7 Schematic diagram of the structure of the lower end surface of the middle rotor;

[0036] In the figure, 1 is the rotor, 2 is the circumferential moving partition, 3 is the special-shaped static partition, 4 is the cold air inlet pipe, 5 is the partition heater (rectangular / fan-shaped), 6 is the partition steam inlet valve, 7 is the three-way valve, 8 is the heat source delivery pipe, 9 is the heat source branch pipe, 10 is the high-temperature steam source pipe, 11 is the low-temperature steam source pipe, the direction of the arrow is the medium flow direction, a is the high-temperature steam source, and b is the low-temperature steam source. DETAILED DESCRIPTION

[0037] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with embodiments, but the content of the present invention is not limited to the following embodiments.

[0038] Example 1

[0039] like Figure 1-2 As shown, a rotary air preheater (in this example, the rotary air preheater has a three-compartment structure, including a flue gas compartment, a primary air compartment and a secondary air compartment) based on heater zoning management, a ring heating system, including a rotor, a circumferential moving baffle, a special-shaped static baffle, a cold air inlet pipe and a heater system;

[0040] The circumferential moving partition is installed on the lower end surface of the rotor, dividing the lower end surface of the rotor into two concentric rings of equal area;

[0041] The cold air inlet pipe is located below the lower end surface of the rotor corresponding to the secondary air compartment, and the upper end surface of the cold air inlet pipe completely covers the secondary air compartment;

[0042] The special-shaped static baffle is installed in the cold air inlet duct, dividing the cold air inlet duct into at least two independent sub-ring air inlet ducts, the two sub-ring air inlet ducts correspond to the two concentric rings one by one, and the sub-ring air inlet ducts are located below the corresponding concentric rings; the upper end surface of the sub-ring air inlet duct is a fan-shaped structure including two arc-shaped edges, and the two arc-shaped edges of the sub-ring air inlet duct are equal to the arcs of the circumferential moving baffles on both sides of the corresponding concentric rings and are opposite to each other up and down; the lower end surface of the sub-ring air inlet duct is a rectangle;

[0043] The heater system includes 2 zoned heaters (rectangular), a heat source delivery pipe and 2 zoned steam inlet valves of the heater. The 2 zoned heaters correspond to the 2 ring-shaped air inlet pipes one by one. The zoned heaters (rectangular) are installed in the rectangular area of ​​the corresponding ring-shaped air inlet pipes (the shapes of the two are adapted to each other); one end of the heat source delivery pipe is connected to the heat source (steam generator) and the other end is branched into 2 heat source branch pipes. The 2 heat source branch pipes, the 2 zoned heaters and the 2 zoned steam inlet valves of the heater correspond to each other one by one. The heat source branch pipes lead to the corresponding zoned heaters. The zoned steam inlet valves of the heaters Installed on the corresponding heat source branch pipe, the zoned steam inlet of the heater is located outside the air preheater; the heat source is divided into high-temperature steam source and low-temperature steam source to enter the heat source delivery pipe. The low-temperature steam heat source is used to prevent low-temperature corrosion, and the temperature is 80-120℃. The high-temperature steam source is used for dry burning (dry burning once every 25 days or so) to solve the problem of ammonium bisulfate deposition, and the temperature is 120-200℃. The high-temperature steam source is transported through the high-temperature steam source pipe, and the low-temperature steam source is transported through the low-temperature steam source pipe. The high-temperature steam source pipe, the low-temperature steam source pipe and the heat source delivery pipe are connected through a three-way valve. The condensed water generated after the heater heat exchange can be connected to the condensate system on the steam turbine side.

[0044] During operation, the three-way valve can be switched to provide high-temperature steam heat source or low-temperature steam heat source to the heater system, and heat is transported to the corresponding zone heater through the heat source branch pipe to increase the temperature of the air in the corresponding concentric rings. In this way, when the flue gas in the corresponding concentric rings exchanges energy with the air, the heat loss of the flue gas will be reduced and the temperature will increase, thereby increasing the wall temperature of the heat storage element in the corresponding concentric ring, and the condensed or crystallized materials adhering to it will gradually vaporize and be discharged from the rotary air preheater rotor along with the heat medium, thereby effectively solving the blockage and corrosion problems of the rotary air preheater.

[0045] Example 2

[0046] like Figure 3-4 As shown, a rotary air preheater (in this example, the rotary air preheater has a three-compartment structure, including a flue gas compartment, a primary air compartment and a secondary air compartment) based on heater zoning management, a ring heating system, including a rotor, a circumferential moving baffle, a special-shaped static baffle, a cold air inlet pipe and a heater system;

[0047] The circumferential moving partition is installed on the lower end surface of the rotor, dividing the lower end surface of the rotor into three concentric rings of equal area;

[0048] The cold air inlet pipe is located below the lower end surface of the rotor corresponding to the secondary air compartment and completely covers the secondary air compartment;

[0049] The special-shaped static baffle is installed in the cold air inlet duct, dividing the cold air inlet duct into at least 3 independent sub-ring air inlet ducts, the 3 sub-ring air inlet ducts correspond to the 3 concentric rings one by one, and the sub-ring air inlet ducts are located below the corresponding concentric rings; the upper end surface of the sub-ring air inlet duct is a fan-shaped structure including two arc-shaped edges, and the two arc-shaped edges of the sub-ring air inlet duct are equal to the arcs of the circumferential moving baffles on both sides of the corresponding concentric rings and are opposite to each other up and down; the lower end surface of the sub-ring air inlet duct is a rectangle;

[0050] The heater system includes 3 zone heaters (rectangles), a heat source delivery pipe and 3 zone steam inlet valves of the heater. The 3 zone heaters correspond one-to-one to the 3 ring air inlet pipes, and the zone heaters (rectangles) are installed in the rectangular areas in the corresponding ring air inlet pipes (the shapes of the two are adapted to each other); one end of the heat source delivery pipe is connected to the heat source (steam generator), and the other end is branched into 3 heat source branch pipes. The 3 heat source branch pipes, 3 zone heaters and 3 zone steam inlet valves of the heater correspond one-to-one. The heat source branch pipes lead to the corresponding zone heaters, and the zone steam inlet valves of the heaters are installed on the corresponding heat source branch pipes. The zoned steam inlet door of the heater is located outside the air preheater; the heat source enters the heat source delivery pipe in two ways: high-temperature steam source and low-temperature steam source. The low-temperature steam heat source is used to prevent low-temperature corrosion, and the temperature is 80-120°C. The high-temperature steam source is used for dry burning (one round of dry burning every 25 days or so) to solve the problem of ammonium bisulfate deposition, and the temperature is 120-200°C. The high-temperature steam source is transported through the high-temperature steam source pipe, and the low-temperature steam source is transported through the low-temperature steam source pipe. The high-temperature steam source pipe, the low-temperature steam source pipe and the heat source delivery pipe are connected through a three-way valve. The condensed water generated after the heater heat exchange can be connected to the condensate system on the turbine side.

[0051] During operation, the three-way valve can be switched to provide high-temperature steam heat source or low-temperature steam heat source to the heater system, and heat is transported to the corresponding zone heater through the heat source branch pipe to increase the temperature of the air in the corresponding concentric rings. In this way, when the flue gas in the corresponding concentric rings exchanges energy with the air, the heat loss of the flue gas will be reduced and the temperature will increase, thereby increasing the wall temperature of the heat storage element in the corresponding concentric ring, and the condensed or crystallized materials adhering to it will gradually vaporize and be discharged from the rotary air preheater rotor along with the heat medium, thereby effectively solving the blockage and corrosion problems of the rotary air preheater.

[0052] Example 3

[0053] On the basis of Example 1 or 2, the following improvements were further made: Figure 5-6 As shown, a sealing pair is provided between the split ring air inlet pipe and the circumferential moving baffles on both sides of the corresponding concentric ring, and the sealing pair includes a sealing sheet provided on the circumferential moving baffle and a sealing surface provided on the two arc-shaped edges of the split ring air inlet pipe. The zoned air heater is installed in the annular area of ​​the split ring air inlet pipe, and the zoned air heater structure is a fan-shaped structure adapted to the annular area in the split ring air inlet pipe.

[0054] Example 4

[0055] On the basis of Example 2, the following improvements were further made: Figure 7-8 As shown, a sealing pair is provided between the ring-shaped air inlet pipe and the circumferential moving baffles on both sides of the corresponding concentric ring. The sealing pair includes a sealing sheet provided on the circumferential moving baffle and a sealing surface provided on the two arc-shaped edges of the ring-shaped air inlet pipe. Each zone heater is a rotary heater. The zone heater is installed in the annular area of ​​the ring-shaped air inlet pipe, and the zone heater structure is a fan-shaped structure adapted to the annular area in the ring-shaped air inlet pipe.

[0056] The 2×660MW (#1, #2) units of the coal-fired power plant are each equipped with two three-compartment rotary air preheaters, and the cold secondary air sides are connected through a connecting pipe. The cold end face of the air preheater rotor of the #1 unit is divided into three concentric rings of equal area, and the cold secondary air duct is matched with a three-ring air inlet, and the air inlet volume of each ring is adjusted by the split-ring regulating door. When the split-ring regulating doors of the two air preheaters are fully opened, the exhaust temperature of the two air preheaters is about 126°C; when the opening of one split-ring regulating door is reduced to about 20%, the exhaust temperature of this ring rises to about 205°C, and the corresponding exhaust temperatures of other rings all drop to about 114°C, posing a risk of low-temperature corrosion. The #2 unit adopts the solution of the present application (Example 4), and each air preheater is thermally managed in a zone according to a three-ring heater of equal area. When no steam is introduced into the heater, the exhaust temperatures of the two air preheaters are both around 126°C; when steam at around 185°C is introduced into one of the sub-rings, the exhaust temperature of the ring rises to around 205°C, and the corresponding exhaust temperatures of other rings remain basically unchanged, avoiding the low-temperature corrosion problem that may be caused by too low flue gas temperature.

[0057] It has been verified in practice that the rotary air preheater sub-ring heating systems based on heater zoning management in the above-mentioned examples can provide high-temperature steam heat source or low-temperature steam heat source to the heater system through the switching of the three-way valve, and transmit heat to the corresponding zone heater through the heat source branch pipe to increase the temperature of the air in the corresponding concentric rings, thereby increasing the wall temperature of the heat storage element in the corresponding concentric rings, so that the condensed or crystallized materials adhering to the heat storage element are gradually vaporized and discharged from the rotary air preheater rotor along with the heat medium, thereby effectively solving the blockage and corrosion problems of the rotary air preheater; when using the above-mentioned system anti-blocking, there is no need to reduce the air volume of the heating ring, and thus the air volume of other rings (non-heating rings) will not change due to the heating of a certain ring, which effectively solves the problems of local corrosion and ash blockage caused by changes in the air volume of the non-heating ring.

Claims

1. A rotary air preheater ring heating system based on heater zone management, characterized in that: It includes a rotor, a circumferential moving baffle, a special-shaped static baffle, a cold air inlet pipe and a heater system; The circumferential moving partition is installed on the lower end surface of the rotor, dividing the lower end surface of the rotor into N concentric rings, N ≥ 2; The cold air inlet pipe is located below the lower end surface of the rotor and covers at least one air compartment; The special-shaped static baffle is installed in the cold air inlet duct, dividing the cold air inlet duct into at least N independent sub-ring air inlet ducts, the N sub-ring air inlet ducts correspond to the N concentric rings one by one, and the sub-ring air inlet ducts are located below the corresponding concentric rings; The heater system includes at least N zone heaters, a heat source delivery pipe, N heat source branch pipes and N zone steam inlet valves of the heater. The N zone heaters correspond one-to-one to the N sub-ring air inlet pipes, and the zone heaters are installed in the corresponding sub-ring air inlet pipes; one end of the heat source delivery pipe is connected to the heat source, and the other end is divided into N heat source branch pipes. The N heat source branch pipes, N zone heaters and N zone steam inlet valves of the heater correspond one-to-one, the heat source branch pipes lead to the corresponding zone heaters, and the heater zone steam inlet valves are installed on the corresponding heat source branch pipes.

2. The rotary air preheater ring heating system based on heater zone management as claimed in claim 1 is characterized in that: The areas of the N concentric rings are equal.

3. The rotary air preheater ring heating system based on heater zone management as claimed in claim 1 or 2, characterized in that: The value of N is 2, 3 or 4.

4. The rotary air preheater ring heating system based on heater zone management as claimed in claim 1 or 2, characterized in that: The heat source enters the heat source delivery pipe in two ways: a high-temperature steam source and a low-temperature steam source.

5. The rotary air preheater ring heating system based on heater zone management as claimed in claim 4 is characterized in that: The high-temperature steam source is transported through the high-temperature steam source pipe, the low-temperature steam source is transported through the low-temperature steam source pipe, and the high-temperature steam source pipe, the low-temperature steam source pipe and the heat source transport pipe are connected through a three-way valve.

6. The rotary air preheater ring heating system based on heater zone management as claimed in claim 1 or 2, characterized in that: The upper end face of the split-ring air inlet duct is a fan-shaped structure including two arcuate edges. The two arcuate edges of the split-ring air inlet duct are equal to the curvature of the circumferential dynamic partitions on both sides of the corresponding concentric rings and are opposite to each other up and down; the lower end face of the split-ring air inlet duct is a rectangle.

7. The rotary air preheater ring heating system based on heater zone management as claimed in claim 6, characterized in that: The zoned air heater is designed as a fan-shaped structure or a rectangular structure according to the position of the divided ring air inlet duct.

8. The rotary air preheater ring heating system based on heater zone management as claimed in claim 1 or 2, characterized in that: A sealing pair is provided between the divided-ring air inlet pipe and the circumferential moving partitions on both sides of the corresponding concentric ring.

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