Rotary air pre-heater sealing system

Abstract

The utility model relates to the technical field of air pre-heaters, and discloses a sealing system of a rotary air pre-heater, which is characterized in that a part of hot flue gas is led out from an inlet main flue of the air pre-heater through a first hot flue gas branch pipeline and a second hot flue gas branch pipeline, and an air leakage blocking area is formed below a sealing sector plate at the hot end of the rotary air pre-heater; a part of dedusted cold flue gas is led out from the main flue at the outlet of the dust remover through the first cold flue gas branch pipeline and the second cold flue gas branch pipeline, and an air leakage blocking area is formed below a sealing sector plate at the cold end of the rotary air pre-heater, so that the air leakage blocking area can be utilized to eliminate the pressure difference between the air side and the area below the sealing sector plate; therefore, air is blocked, and radial air leakage of the rotary air pre-heater is effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of air preheaters, and in particular to a rotary air preheater sealing system. Background Art

[0002] Rotary air preheater is widely used in coal-fired power plants as an important heat exchange equipment at the tail of the boiler due to its compact structure, high heat exchange efficiency and flexible layout.

[0003] However, in the rotary air preheater, since the air side is under positive pressure and the flue gas side is under negative pressure, the air will leak from the air side to the flue gas side through the gap between the sealing fan plate and the rotor under the action of the pressure difference. At the same time, the rotor has a large temperature gradient in the vertical direction, and the expansion of the hot end is greater than that of the cold end. Under the action of gravity, the rotor appears "mushroom-shaped", and the center of the rotor is higher than the edge of the rotor, which further increases the gap between the sealing fan plate and the rotor, and the air leakage further increases.

[0004] The above reasons lead to a generally high air leakage rate in rotary air preheaters. A high air leakage rate will increase the heat loss of flue gas, thereby reducing the thermal efficiency of the boiler and increasing the power consumption of the three major fans. Utility Model Content

[0005] The purpose of this application is to provide a rotary air preheater sealing system to overcome the problem in the prior art that the high air leakage rate of the rotary air preheater leads to increased exhaust heat loss and thus reduced boiler thermal efficiency.

[0006] In order to achieve the above-mentioned object, the present application provides a rotary air preheater sealing system, the rotary air preheater sealing system comprising a rotary air preheater, a dust collector, an air preheater inlet main flue, a first hot flue gas branch pipeline, a second hot flue gas branch pipeline, a dust collector outlet main flue, a first cold flue gas branch pipeline and a second cold flue gas branch pipeline;

[0007] The main flue at the inlet of the air preheater, the rotary air preheater, the dust collector and the main flue at the outlet of the dust collector are connected in sequence;

[0008] The flue gas duct of the rotary air preheater is the flue gas side, the air duct of the rotary air preheater is the air side, the hot end of the rotary air preheater is provided with a first sealing fan plate and a second sealing fan plate, the first sealing fan plate and the second sealing fan plate are both located between the air side and the flue gas side, and the first sealing fan plate and the second sealing fan plate are both provided with air inlets;

[0009] The cold end of the rotary air preheater is provided with a third sealing sector plate and a fourth sealing sector plate, the third sealing sector plate and the fourth sealing sector plate are both located between the air side and the flue gas side, and the third sealing sector plate and the fourth sealing sector plate are both provided with air inlets;

[0010] The inlet of the first hot flue gas branch pipeline is communicated with the main flue at the air preheater inlet, and the outlet of the first hot flue gas branch pipeline is communicated with the air inlet on the first sealing sector plate; the inlet of the second hot flue gas branch pipeline is communicated with the main flue at the air preheater inlet, and the outlet of the second hot flue gas branch pipeline is communicated with the air inlet on the second sealing sector plate;

[0011] The inlet of the first cold smoke gas branch pipeline is connected to the main flue at the dust collector outlet, and the outlet of the first cold smoke gas branch pipeline is connected to the air inlet on the third sealing fan-shaped plate; the inlet of the second cold smoke gas branch pipeline is connected to the main flue at the dust collector outlet, and the outlet of the second cold smoke gas branch pipeline is connected to the air inlet on the fourth sealing fan-shaped plate.

[0012] In an embodiment of the present application, the rotary air preheater sealing system further includes a first fan and a second fan;

[0013] The first fan is arranged on the first hot flue gas branch pipe, and the second fan is arranged on the second hot flue gas branch pipe.

[0014] In the embodiment of the present application, the rotary air preheater sealing system further includes a first pressure detection device, a second pressure detection device, a third pressure detection device and a fourth pressure detection device;

[0015] The first pressure detection device is arranged under the first sealing sector plate, and the second pressure detection device is arranged on the air side of the hot end of the rotary air preheater;

[0016] The third pressure detection device is arranged under the second sealing sector plate, and the fourth pressure detection device is arranged on the air side of the hot end of the rotary air preheater.

[0017] In the embodiment of the present application, the rotary air preheater sealing system further includes a third fan and a fourth fan;

[0018] The third fan is arranged on the first cold flue gas branch pipe, and the fourth fan is arranged on the second cold flue gas branch pipe.

[0019] In the embodiment of the present application, the rotary air preheater sealing system further includes a fifth pressure detection device, a sixth pressure detection device, a seventh pressure detection device and an eighth pressure detection device;

[0020] The fifth pressure detection device is arranged under the third sealing sector plate, and the sixth pressure detection device is arranged on the air side of the cold end of the rotary air preheater;

[0021] The seventh pressure detection device is arranged under the fourth sealing fan plate, and the eighth pressure detection device is arranged on the air side of the cold end of the rotary air preheater.

[0022] In an embodiment of the present application, the rotary air preheater sealing system further includes a control server;

[0023] The first fan, the second fan, the third fan, the fourth fan, the first pressure detection device, the second pressure detection device, the third pressure detection device, the fourth pressure detection device, the fifth pressure detection device, the sixth pressure detection device, the seventh pressure detection device and the eighth pressure detection device are all connected to the control server.

[0024] In the embodiment of the present application, the rotary air preheater sealing system further includes a first inlet valve, a second inlet valve, a first outlet valve, and a second outlet valve;

[0025] The first inlet valve and the first outlet valve are both arranged on the first hot flue gas branch pipeline, the first inlet valve is located upstream of the first fan, and the first outlet valve is located downstream of the first fan;

[0026] The second inlet valve and the second outlet valve are both arranged on the second hot flue gas branch pipeline, the second inlet valve is located upstream of the second fan, and the second outlet valve is located downstream of the second fan.

[0027] In the embodiment of the present application, the rotary air preheater sealing system further includes a third inlet valve, a fourth inlet valve, a third outlet valve and a fourth outlet valve;

[0028] The third inlet valve and the third outlet valve are both arranged on the first cold flue gas branch pipeline, the third inlet valve is located upstream of the third fan, and the third outlet valve is located downstream of the third fan;

[0029] The fourth inlet valve and the fourth outlet valve are both arranged on the second cold flue gas branch pipeline, the fourth inlet valve is located upstream of the fourth fan, and the fourth outlet valve is located downstream of the fourth fan.

[0030] In the embodiment of the present application, the first sealing fan-shaped plate, the second sealing fan-shaped plate, the third sealing fan-shaped plate and the fourth sealing fan-shaped plate are all provided with a plurality of air inlets;

[0031] Along the smoke flow direction, the opening size of each air inlet on the first sealing sector plate and the opening size of each air inlet on the second sealing sector plate gradually decrease;

[0032] Along the smoke flow direction, the opening size of each air inlet on the third sealing sector plate and the opening size of each air inlet on the fourth sealing sector plate gradually increase.

[0033] In an embodiment of the present application, the air side is divided into a primary air side and a secondary air side; the first sealing fan plate is located between the primary air side and the smoke side, the second sealing fan plate is located between the secondary air side and the smoke side, the third sealing fan plate is located between the primary air side and the smoke side, and the fourth sealing fan plate is located between the secondary air side and the smoke side.

[0034] Through the above-mentioned rotary air preheater sealing system, the rotary air preheater sealing system includes a rotary air preheater, a dust collector, an air preheater inlet main flue, a first hot flue gas branch pipeline, a second hot flue gas branch pipeline, a dust collector outlet main flue, a first cold flue gas branch pipeline and a second cold flue gas branch pipeline; the air preheater inlet main flue, the rotary air preheater, the dust collector and the dust collector outlet main flue are connected in sequence; the flue gas duct of the rotary air preheater is the flue gas side, the air duct of the rotary air preheater is the air side, the hot end of the rotary air preheater is provided with a first sealing fan plate and a second sealing fan plate, the first sealing fan plate and the second sealing fan plate are both located between the air side and the flue gas side, and the first sealing fan plate and the second sealing fan plate are both provided with air inlets; the cold end of the rotary air preheater is provided with a third sealing fan plate and a fourth sealing fan plate, The third sealing fan-shaped plate and the fourth sealing fan-shaped plate are both located between the air side and the flue gas side, and air inlets are provided on the third sealing fan-shaped plate and the fourth sealing fan-shaped plate; the inlet of the first hot flue gas branch pipeline is connected to the main flue at the air preheater inlet, and the outlet of the first hot flue gas branch pipeline is connected to the air inlet on the first sealing fan-shaped plate; the inlet of the second hot flue gas branch pipeline is connected to the main flue at the air preheater inlet, and the outlet of the second hot flue gas branch pipeline is connected to the air inlet on the second sealing fan-shaped plate; the inlet of the first cold flue gas branch pipeline is connected to the main flue at the dust collector outlet, and the outlet of the first cold flue gas branch pipeline is connected to the air inlet on the third sealing fan-shaped plate; the inlet of the second cold flue gas branch pipeline is connected to the main flue at the dust collector outlet, and the outlet of the second cold flue gas branch pipeline is connected to the air inlet on the fourth sealing fan-shaped plate. Based on the solution provided in the embodiment of the present application, an air leakage barrier zone can be formed at the gap between each sealing sector plate and the rotor. The air leakage barrier zone can eliminate the pressure difference between the air side and the area below the sealing sector plate, thereby blocking the air and effectively reducing the radial air leakage of the rotary air preheater.

[0035] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings:

[0037] Figure 1 and Figure 2 A schematic structural diagram of a rotary air preheater sealing system according to an embodiment of the present application is shown;

[0038] Figure 3 A schematic diagram shows the flue gas flow and air flow conditions in a rotary air preheater sealing system according to an embodiment of the present application.

[0039] Description of Reference Numerals

[0040] 101—rotary air preheater; 1011—first sealing fan plate; 1012—second sealing fan plate; 1013—third sealing fan plate; 1014—fourth sealing fan plate; 102—dust collector; 103—main flue at the inlet of air preheater; 104—first hot flue gas branch line; 105—second hot flue gas branch line; 106—main flue at the outlet of dust collector; 107—first cold flue gas branch line; 108—second cold flue gas branch line; 109—first fan; 110—first inlet valve; 111—first outlet valve; 112—second fan; 113—first fan; 114—first fan; 115—first fan; 116—first fan; 117—first fan; 118—first fan; 119—first fan; 120—first fan; 121—first fan; 122—first fan; 123—first fan; 124—first fan; 125—first fan; 126—first fan; 127—first fan; 128—first fan; 129—first fan; 130—first fan; 131—first fan; 132—first fan; 133—first fan; 134—first fan; 135—first fan; 136—first fan; 137—first fan; 138—first fan; 139—first fan; 140—first fan; 141—first fan; 142—first fan; 143—first fan; 144—first fan; 145—first fan; 146—first fan; 147—first fan; 148—first fan; 149—first fan; 150—first fan; 151—first fan; 152—first fan; 153— 3—second inlet valve; 114—second outlet valve; 115—third fan; 116—third inlet valve; 117—third outlet valve; 118—fourth fan; 119—fourth inlet valve; 120—fourth outlet valve; 121—first pressure detection device; 122—second pressure detection device; 123—third pressure detection device; 124—fourth pressure detection device; 125—fifth pressure detection device; 126—sixth pressure detection device; 127—seventh pressure detection device; 128—eighth pressure detection device; 129—control server. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0042] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0043] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0044] As described in the background technology, the rotary air preheater is widely used in coal-fired power plants as an important heat exchange equipment at the tail of the boiler due to its compact structure, high heat exchange efficiency and flexible layout. However, due to the influence of factors such as structural form, thermal expansion, and self-gravity, the rotary air preheater generally has a high air leakage rate. The rotary air preheater is usually designed to have an air leakage rate below 5%, but the air leakage rate is as high as 10% to 20%, or even 30% during actual operation. Among the various types of air leakage in the rotary air preheater, radial air leakage accounts for the largest proportion of the total air leakage. The reasons for radial air leakage may include: the air side is positive pressure, the flue gas side is negative pressure, and under the action of the pressure difference, the air will leak from the air side to the flue gas side through the gap between the sealing fan plate and the rotor, thereby forming radial air leakage. At the same time, the rotor has a large temperature gradient in the vertical direction, and the expansion of the hot end is greater than that of the cold end, resulting in the rotor being "mushroom-shaped", and the center of the rotor is higher than the edge of the rotor, which further increases the gap between the sealing fan plate and the rotor, further increasing the radial air leakage. In practical applications, a high air leakage rate of the rotary air preheater will increase the heat loss of flue gas, thereby reducing the thermal efficiency of the boiler. Data show that for every 1°C increase in flue gas temperature, the thermal efficiency of the boiler decreases by about 0.05%. In addition, a high air leakage rate of the rotary air preheater will also reduce the primary and secondary air supply volume, reducing the maximum load of the coal-fired power unit.

[0045] In view of this, in one embodiment of the present application, a rotary air preheater sealing system is provided, such as Figure 1 Shown and Figure 2 As shown (where Figure 1 This is a schematic diagram of the hot end of a rotary air preheater. Figure 2Schematic diagram of the cold end of a rotary air preheater), the rotary air preheater sealing system may include a rotary air preheater 101, a dust collector 102, an air preheater inlet main flue 103, a first hot flue gas branch pipeline 104, a second hot flue gas branch pipeline 105, a dust collector outlet main flue 106, a first cold flue gas branch pipeline 107 and a second cold flue gas branch pipeline 108; the air preheater inlet main flue 103, the rotary air preheater 101, the dust collector 102 and the dust collector outlet main flue 106 are connected in sequence; the The hot end of the rotary air preheater 101 is provided with a first sealing fan plate 1011 and a second sealing fan plate 1012, the first sealing fan plate 1011 and the second sealing fan plate 1012 are both located between the air side and the flue gas side, and the first sealing fan plate 1011 and the second sealing fan plate 1012 are both provided with an air inlet A; the cold end of the rotary air preheater 101 is provided with a third sealing fan plate 1013 and a fourth sealing fan plate 1014, the third sealing fan plate 1013 and the first sealing fan plate 1014 are provided with an air inlet A. The four sealing fan-shaped plates 1014 are all located between the air side and the flue gas side, and the third sealing fan-shaped plate 1013 and the fourth sealing fan-shaped plate 1014 are both provided with an air inlet A; the inlet of the first hot flue gas branch pipeline 104 is connected to the main flue 103 at the air preheater inlet, and the outlet of the first hot flue gas branch pipeline 104 is connected to the air inlet A on the first sealing fan-shaped plate 1011; the inlet of the second hot flue gas branch pipeline 105 is connected to the main flue 103 at the air preheater inlet, and the outlet of the first hot flue gas branch pipeline 104 is connected to the air inlet A on the first sealing fan-shaped plate 1011; The outlet of the pipeline 105 is connected to the air inlet A on the second sealed fan-shaped plate 1012; the inlet of the first cold smoke gas branch pipeline 107 is connected to the main flue 106 at the dust collector outlet, and the outlet of the first cold smoke gas branch pipeline 107 is connected to the air inlet A on the third sealed fan-shaped plate 1013; the inlet of the second cold smoke gas branch pipeline 108 is connected to the main flue 106 at the dust collector outlet, and the outlet of the second cold smoke gas branch pipeline 108 is connected to the air inlet A on the fourth sealed fan-shaped plate 1014.

[0046] In the rotary air preheater 101, the flue gas can flow from top to bottom, and the air (such as primary air and secondary air) can flow from bottom to top. Figure 1 and Figure 2 The gas flow direction is shown by the arrows.

[0047] The flue gas side can be understood as the air duct for passing flue gas in the rotary air preheater 101, referred to as the flue gas duct; the air side can be understood as the air duct for passing air in the rotary air preheater 101, referred to as the air duct. The hot end of the rotary air preheater 101 can be the end corresponding to the entrance of hot flue gas, and the cold end of the rotary air preheater 101 can be the end corresponding to the outflow of cold flue gas.

[0048] The main flue 103 at the air preheater inlet can be used to introduce hot flue gas into the flue duct of the rotary air preheater 101, and the hot flue gas can come from the flue at the tail of the boiler. The first hot flue gas branch pipeline 104 and the second hot flue gas branch pipeline 105 can be used to lead out part of the hot flue gas from the main flue 103 at the air preheater inlet. The main flue 106 at the dust collector outlet can be used to lead out the cold flue gas after dust removal from the dust collector 102. The first cold flue gas branch pipeline 107 and the second cold flue gas branch pipeline 108 can be used to lead out part of the cold flue gas after dust removal from the main flue 106 at the dust collector outlet.

[0049] In the embodiment of the present application, the main flue 103 at the air preheater inlet, the rotary air preheater 101, the dust collector 102 and the main flue 106 at the dust collector outlet are connected in sequence, which can be understood as follows: the hot flue gas is input from the main flue 103 at the air preheater inlet to the rotary air preheater 101, and after the hot flue gas completes heat exchange with the air in the rotary air preheater 101, the cold flue gas with reduced temperature flows out of the rotary air preheater 101 and further flows into the dust collector 102 for dust removal, and the cold flue gas after dust removal flows into the main flue 106 at the dust collector outlet.

[0050] In one embodiment, the first sealing fan plate 1011 and the second sealing fan plate 1012 are both located between the air side and the flue gas side of the hot end of the rotary air preheater 101, and the third sealing fan plate 1013 and the fourth sealing fan plate 1014 are both located between the air side and the flue gas side of the cold end of the rotary air preheater 101. Specifically, it may include: the first sealing fan plate 1011 is located between the primary air side and the flue gas side of the hot end of the rotary air preheater 101, the second sealing fan plate 1012 is located between the secondary air side and the flue gas side of the hot end of the rotary air preheater 101, the third sealing fan plate 1013 is located between the primary air side and the flue gas side of the cold end of the rotary air preheater 101, and the fourth sealing fan plate 1014 is located between the secondary air side and the flue gas side of the cold end of the rotary air preheater 101. The primary air side can be understood as the air duct for passing primary air in the rotary air preheater 101, referred to as the primary air duct; the secondary air side can be understood as the air duct for passing secondary air in the rotary air preheater 101, referred to as the secondary air duct. That is, the rotary air preheater 101 can be a three-compartment rotary air preheater, and the air side is divided into a primary air side and a secondary air side.

[0051] In the embodiment of the present application, the inlet of the first hot flue gas branch pipeline 104 is connected to the main flue 103 at the air preheater inlet, and the outlet of the first hot flue gas branch pipeline 104 is connected to the air inlet A on the first sealing fan plate 1011. It can be understood that: the first hot flue gas branch pipeline 104 draws out part of the hot flue gas from the main flue 103 at the air preheater inlet, and transports the drawn hot flue gas to the air inlet A on the first sealing fan plate 1011, and the hot flue gas entering the air inlet A flows toward the rotor. In practical applications, in order to facilitate the introduction of hot flue gas into the air inlet A on the first sealing fan plate 1011, the rotary air preheater sealing system may also include a first fan 109, which is arranged on the first hot flue gas branch pipeline 104. Furthermore, in order to facilitate the control of the flow of hot flue gas in the first hot flue gas branch pipeline 104, the rotary air preheater sealing system may also include a first inlet valve 110 and a first outlet valve 111, and the first inlet valve 110 and the first outlet valve 111 are both arranged on the first hot flue gas branch pipeline 104, the first inlet valve 110 is located upstream of the first fan 109, and the first outlet valve 111 is located downstream of the first fan 109.

[0052] The inlet of the second hot flue gas branch pipeline 105 is connected to the main flue 103 at the air preheater inlet, and the outlet of the second hot flue gas branch pipeline 105 is connected to the air inlet A on the second sealing sector plate 1012. It can be understood that the second hot flue gas branch pipeline 105 draws out part of the hot flue gas from the main flue 103 at the air preheater inlet, and transports the drawn hot flue gas to the air inlet A on the second sealing sector plate 1012, and the hot flue gas entering the air inlet A flows toward the rotor. In practical applications, in order to facilitate the introduction of hot flue gas into the air inlet A on the second sealing sector plate 1012, the rotary air preheater sealing system may also include a second fan 112, which is arranged on the second hot flue gas branch pipeline 105. Furthermore, in order to facilitate the control of the flow of hot flue gas in the second hot flue gas branch pipeline 105, the rotary air preheater sealing system may also include a second inlet valve 113 and a second outlet valve 114, and the second inlet valve 113 and the second outlet valve 114 are both arranged on the second hot flue gas branch pipeline 105, the second inlet valve 113 is located upstream of the second fan 112, and the second outlet valve 114 is located downstream of the second fan 112.

[0053] The inlet of the first cold flue gas branch pipeline 107 is connected to the main flue 106 at the dust collector outlet, and the outlet of the first cold flue gas branch pipeline 107 is connected to the air inlet A on the third sealing fan plate 1013. It can be understood that: the first cold flue gas branch pipeline 107 draws out part of the cold flue gas from the main flue 106 at the dust collector outlet, and transports the drawn cold flue gas to the air inlet A on the third sealing fan plate 1013, and the hot flue gas entering the air inlet A flows toward the rotor. In practical applications, in order to facilitate the introduction of cold flue gas into the air inlet A on the third sealing fan plate 1013, the rotary air preheater sealing system can also include a third fan 115, which is arranged on the first cold flue gas branch pipeline 107. Furthermore, in order to facilitate the control of the flow of cold flue gas in the first cold flue gas branch pipeline 107, the rotary air preheater sealing system may also include a third inlet valve 116 and a third outlet valve 117, and the third inlet valve 116 and the third outlet valve 117 are both arranged on the first cold flue gas branch pipeline 107, the third inlet valve 116 is located upstream of the third fan 115, and the third outlet valve 117 is located downstream of the third fan 115.

[0054] The inlet of the second cold flue gas branch pipeline 108 is connected to the main flue 106 at the dust collector outlet, and the outlet of the second cold flue gas branch pipeline 108 is connected to the air inlet A on the fourth sealing fan plate 1014. It can be understood that the second cold flue gas branch pipeline 108 draws part of the cold flue gas from the main flue 106 at the dust collector outlet, and transports the drawn cold flue gas to the air inlet A on the fourth sealing fan plate 1014, and the hot flue gas entering the air inlet A flows toward the rotor. In practical applications, in order to facilitate the introduction of cold flue gas into the air inlet A on the fourth sealing fan plate 1014, the rotary air preheater sealing system can also include a fourth fan 118, which is arranged on the second cold flue gas branch pipeline 108. Furthermore, in order to facilitate the control of the flow of cold flue gas in the second cold flue gas branch pipeline 108, the rotary air preheater sealing system may also include a fourth inlet valve 119 and a fourth outlet valve 120, and the fourth inlet valve 119 and the fourth outlet valve 120 are both arranged on the second cold flue gas branch pipeline 108, the fourth inlet valve 119 is located upstream of the fourth fan 118, and the fourth outlet valve 120 is located downstream of the fourth fan 118.

[0055] Thus, air leakage isolation zones extending from the sealing fan plate to the rotor can be formed at the gap between the first sealing fan plate 1011 and the rotor, at the gap between the second sealing fan plate 1012 and the rotor, at the gap between the third sealing fan plate 1013 and the rotor, and at the gap between the fourth sealing fan plate 1014 and the rotor.

[0056] In the rotary air preheater sealing system, the flow of flue gas and air (such as primary air and secondary air) can be described as follows: Figure 3 shown.

[0057] It can be understood that the rotary air preheater sealing system provided in the embodiment of the present application includes a rotary air preheater 101, a dust collector 102, an air preheater inlet main flue 103, a first hot flue gas branch pipeline 104, a second hot flue gas branch pipeline 105, a dust collector outlet main flue 106, a first cold flue gas branch pipeline 107 and a second cold flue gas branch pipeline 108; the air preheater inlet main flue 103, the rotary air preheater 101, the dust collector 102 and the dust collector outlet main flue 106 are connected in sequence. The hot end of the rotary air preheater 101 is provided with a first sealing fan plate 1011 and a second sealing fan plate 1012, the first sealing fan plate 1011 and the second sealing fan plate 1012 are both located between the air side and the flue gas side, and the first sealing fan plate 1011 and the second sealing fan plate 1012 are both provided with an air inlet A; the cold end of the rotary air preheater 101 is provided with a third sealing fan plate 1013 and a fourth sealing fan plate 1014, the third sealing fan plate 1013 and The fourth sealing fan-shaped plate 1014 is located between the air side and the flue gas side, and the third sealing fan-shaped plate 1013 and the fourth sealing fan-shaped plate 1014 are both provided with an air inlet A; the inlet of the first hot flue gas branch pipeline 104 is connected to the main flue 103 at the air preheater inlet, and the outlet of the first hot flue gas branch pipeline 104 is connected to the air inlet A on the first sealing fan-shaped plate 1011; the inlet of the second hot flue gas branch pipeline 105 is connected to the main flue 103 at the air preheater inlet, and the outlet of the first hot flue gas branch pipeline 104 is connected to the air inlet A on the first sealing fan-shaped plate 1011; The outlet of the branch pipeline 105 is connected to the air inlet A on the second sealing fan-shaped plate 1012; the inlet of the first cold flue gas branch pipeline 107 is connected to the main flue 106 at the dust collector outlet, and the outlet of the first cold flue gas branch pipeline 107 is connected to the air inlet A on the third sealing fan-shaped plate 1013; the inlet of the second cold flue gas branch pipeline 108 is connected to the main flue 106 at the dust collector outlet, and the outlet of the second cold flue gas branch pipeline 108 is connected to the air inlet A on the fourth sealing fan-shaped plate 1014. Based on the solution provided in the embodiment of the present application, an air leakage barrier zone can be formed at the gap between each sealing fan-shaped plate and the rotor, and the air leakage barrier zone can eliminate the pressure difference between the air side and the area below the sealing fan-shaped plate, thereby blocking the air and effectively reducing the radial air leakage of the rotary air preheater. At the same time, at the hot end of the rotary air preheater 101, by using the hot flue gas to form an air leakage barrier, even if the hot flue gas leaks to the flue gas side, it will not cause the flue gas temperature at the hot end flue gas side of the rotary air preheater 101 to decrease, thereby ensuring the heat exchange efficiency of the rotary air preheater 101. In addition, by using the hot flue gas to form an air leakage barrier, even if the hot flue gas leaks to the flue gas side, it will not cause the flue gas flow rate to increase, thereby reducing the power consumption of the induced draft fan.At the cold end of the rotary air preheater 101, by using the dust-removed cold flue gas to form an air leakage barrier zone, the dust in the flue gas can be prevented from scouring the sealing fan plate and the rotor, thereby reducing the wear of the sealing fan plate and the rotor. In addition, the cold flue gas flow forming the air leakage barrier zone at the cold end of the rotary air preheater 101 will flow out of the rotary air preheater 101 together with the cold flue gas on the flue gas side, and will not enter the rotary air preheater 101 to participate in heat exchange, thereby further ensuring the heat exchange efficiency of the rotary air preheater 101. In addition, by reducing the radial air leakage of the rotary air preheater, the power consumption of the three major fans (including primary fans, secondary fans and induced draft fans) in the coal-fired power unit can also be reduced.

[0058] In the prior art, cold flue gas may be directed to the hot end of the rotary air preheater to reduce radial air leakage, but it is inevitable that cold flue gas will leak to the flue gas side, which will cause the flue gas temperature at the hot end of the rotary air preheater to decrease, thereby reducing the heat exchange efficiency of the rotary air preheater. The above embodiment of the present application uses hot flue gas to form an air leakage barrier at the hot end of the rotary air preheater. Even if the hot flue gas leaks to the flue gas side, it will not cause the flue gas temperature at the hot end of the rotary air preheater to decrease, thereby ensuring that the rotary air preheater operates with a higher heat exchange efficiency.

[0059] In the prior art, high-pressure air may be used to form an air curtain. Since the high-pressure gas used is air, there is a risk of high-pressure air leaking and mixing with smoke. However, the above embodiment of the present application uses smoke to form an air leakage barrier area, and there is no risk of air and smoke mixing.

[0060] In order to further enhance the sealing performance of each air leakage barrier zone, in one embodiment, the rotary air preheater sealing system further includes a first pressure detection device 121, a second pressure detection device 122, a third pressure detection device 123, a fourth pressure detection device 124, a fifth pressure detection device 125, a sixth pressure detection device 126, a seventh pressure detection device 127 and an eighth pressure detection device 128; the first pressure detection device 121 is arranged under the first sealing sector plate 1011, the second pressure detection device 122 is arranged on the air side of the hot end of the rotary air preheater 101, and is close to the first sealing sector plate 1011; the third pressure detection device 123 is arranged under the first sealing sector plate 1011, and the third pressure detection device 123 is arranged under the first sealing sector plate 1011. The fourth pressure detecting device 124 is arranged under the second sealing fan-shaped plate 1012, and is arranged on the air side of the hot end of the rotary air preheater 101, and is close to the second sealing fan-shaped plate 1012; the fifth pressure detecting device 125 is arranged under the third sealing fan-shaped plate 1013, and the sixth pressure detecting device 126 is arranged on the air side of the cold end of the rotary air preheater 101, and is close to the third sealing fan-shaped plate 1013; the seventh pressure detecting device 127 is arranged under the fourth sealing fan-shaped plate 1014, and the eighth pressure detecting device 128 is arranged on the air side of the cold end of the rotary air preheater 101, and is close to the fourth sealing fan-shaped plate 1014.

[0061] The pressure detection device disposed under the sealing sector plate may be understood as being disposed on a side of the sealing sector plate facing the rotor.

[0062] In the embodiment of the present application, taking the rotary air preheater 101 as a three-compartment rotary air preheater as an example, the first pressure detection device 121 can be used to detect the airflow pressure of the air leakage barrier zone formed under the first sealing fan plate 1011, and the second pressure detection device 122 can be used to detect the airflow pressure on the primary air side of the hot end of the rotary air preheater 101. Therefore, the power and speed of the first fan 109 can be adjusted according to the values ​​detected by the first pressure detection device 121 and the second pressure detection device 122, so that the airflow pressure of the air leakage barrier zone formed under the first sealing fan plate 1011 is equal to or slightly less than the airflow pressure on the primary air side of the hot end of the rotary air preheater 101, thereby greatly reducing the leakage of the primary air to the flue gas side of the hot end of the rotary air preheater 101.

[0063] The third pressure detection device 123 can be used to detect the airflow pressure of the air leakage barrier zone formed under the second sealing sector plate 1012, and the fourth pressure detection device 124 can be used to detect the airflow pressure on the secondary air side of the hot end of the rotary air preheater 101. Therefore, the power and speed of the second fan 112 can be adjusted according to the values ​​detected by the third pressure detection device 123 and the fourth pressure detection device 124, so that the airflow pressure of the air leakage barrier zone formed under the second sealing sector plate 1012 is equal to or slightly less than the airflow pressure on the secondary air side of the hot end of the rotary air preheater 101, thereby greatly reducing the leakage of the secondary air at the hot end of the rotary air preheater 101 to the flue gas side.

[0064] The fifth pressure detection device 125 can be used to detect the airflow pressure of the air leakage barrier zone formed under the third sealing sector plate 1013, and the sixth pressure detection device 126 can be used to detect the airflow pressure on the primary air side of the cold end of the rotary air preheater 101. Therefore, the power and speed of the third fan 115 can be adjusted according to the values ​​detected by the fifth pressure detection device 125 and the sixth pressure detection device 126, so that the airflow pressure of the air leakage barrier zone formed under the third sealing sector plate 1013 is equal to or slightly less than the airflow pressure on the primary air side of the cold end of the rotary air preheater 101, thereby greatly reducing the leakage of the primary air to the flue gas side of the cold end of the rotary air preheater 101.

[0065] The seventh pressure detection device 127 can be used to detect the airflow pressure of the air leakage barrier zone formed under the fourth sealing fan-shaped plate 1014, and the eighth pressure detection device 128 can be used to detect the airflow pressure on the secondary air side of the cold end of the rotary air preheater 101. Therefore, the power and speed of the fourth fan 118 can be adjusted according to the values ​​detected by the seventh pressure detection device 127 and the eighth pressure detection device 128, so that the airflow pressure of the air leakage barrier zone formed under the fourth sealing fan-shaped plate 1014 is equal to or slightly less than the airflow pressure on the secondary air side of the cold end of the rotary air preheater 101, thereby greatly reducing the leakage of the secondary air at the cold end of the rotary air preheater 101 to the flue gas side.

[0066] It can be understood that by setting up various pressure detection devices, the power and speed of each fan are controlled according to the pressure value detected by the pressure detection device, so that the air flow pressure of the air leakage barrier area formed under each sealing fan plate is equal to or slightly less than the air flow pressure on the adjacent air side. The pressure difference between the area under each sealing fan plate and the adjacent air side can be eliminated, and the radial air leakage of the rotary air preheater 101 can be greatly reduced.

[0067] In order to quickly and automatically adjust the air flow pressure of the air leakage barrier area formed under each sealing fan plate, in one embodiment, the rotary air preheater sealing system also includes a control server 129; the first fan 109, the second fan 112, the third fan 115, the fourth fan 118, the first pressure detection device 121, the second pressure detection device 122, the third pressure detection device 123, the fourth pressure detection device 125, the fifth pressure detection device 125, the sixth pressure detection device 126, the seventh pressure detection device 127 and the eighth pressure detection device 128 are all connected to the control server 129.

[0068] In actual applications, the control server 129 can further communicate with the first inlet valve 110, the first outlet valve 111, the second inlet valve 113, the second outlet valve 114, the third inlet valve 116, the third outlet valve 117, the fourth inlet valve 119 and the fourth outlet valve 120; thereby, the operation of the rotary air preheater sealing system can be quickly and automatically controlled.

[0069] In order to form a uniformly sealed air leakage barrier under each sealing fan-shaped plate, in one embodiment, a plurality of air inlets A are provided on each of the first sealing fan-shaped plate 1011, the second sealing fan-shaped plate 1012, the third sealing fan-shaped plate 1013, and the fourth sealing fan-shaped plate 1014; for example, the number of air inlets A provided on each sealing fan-shaped plate may be 3 to 5. Moreover, taking the plurality of air inlets A provided on any sealing fan-shaped plate as an example, the plurality of air inlets A are arranged along the bisector of the sealing fan-shaped plate. More preferably, on the bisector of the sealing fan-shaped plate, the plurality of air inlets A are evenly arranged at equal distances.

[0070] Furthermore, in order to avoid air leakage to the smoke side as much as possible, taking the multiple air inlets A opened on any sealing sector plate as an example, the multiple air inlets A are arranged close to the air side. For example, the multiple air inlets A are arranged along the 1 / 3 bisector of the sealing sector plate, and the 1 / 3 bisector is close to the air side.

[0071] In practical applications, in order to minimize the pressure loss after the smoke enters the air inlet A and enhance the strength and sealing of the air leakage barrier formed under each sealing sector plate, in one embodiment, along the direction of smoke flow, the opening size of each air inlet A on the first sealing sector plate 1011 and the opening size of each air inlet A on the second sealing sector plate 1012 gradually decrease; along the direction of smoke flow, the opening size of each air inlet A on the third sealing sector plate 1013 and the opening size of each air inlet A on the fourth sealing sector plate 1014 gradually increase. More preferably, each air inlet A can be conical.

[0072] According to calculations, the solution provided in the embodiment of the present application can effectively reduce radial air leakage, and the air leakage rate of the rotary air preheater can be reduced to 1% to 4%. Especially for units with small margins of the three major fans, it has a significant effect on ensuring the maximum output of the unit.

[0073] Taking a typical 1000MW coal-fired unit as an example, for every 1% reduction in the rotary air preheater leakage rate, the heat exchange efficiency can be improved by 1.13%. Based on an annual operating hour of 5,500 hours, this is equivalent to an average saving of 2,255 tons of standard coal, with direct economic benefits of approximately RMB 1.7544 million (calculated at a coal price of RMB 778 per ton).

[0074] Taking a typical 1000MW coal-fired unit as an example, based on the plant electricity cost of 0.4 yuan / kw·h and an annual operation of 5500 hours, for every 1% reduction in the rotary air preheater leakage rate, the primary fan power consumption can be saved by 141.72kW, the induced draft fan power consumption can be saved by 85.03kW, and after deducting the power consumption of the newly added fans (the first fan, the second fan, the third fan and the fourth fan), the total direct economic benefits are about 187,100 yuan. For every 1% reduction in the rotary air preheater secondary air leakage rate, the secondary fan power consumption can be saved by 56.69kW, the induced draft fan power consumption can be saved by 85.03kW, and after deducting the power consumption of the newly added fans, the total direct economic benefits are about 187,100 yuan.

[0075] It should be understood that the rotary air preheater 101 can also be a four-compartment rotary air preheater, etc. When the rotary air preheater 101 is a four-compartment rotary air preheater, etc., the four-compartment rotary air preheater, etc. can be adaptively modified according to the scheme provided in the above embodiment of the present application, and these modifications should be included in the scope of the claims of the present application.

[0076] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0077] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A rotary air preheater sealing system, characterized in that: The rotary air preheater sealing system comprises a rotary air preheater, a dust collector, an air preheater inlet main flue, a first hot flue gas branch pipeline, a second hot flue gas branch pipeline, a dust collector outlet main flue, a first cold flue gas branch pipeline and a second cold flue gas branch pipeline; The main flue at the inlet of the air preheater, the rotary air preheater, the dust collector and the main flue at the outlet of the dust collector are connected in sequence; The flue gas duct of the rotary air preheater is the flue gas side, the air duct of the rotary air preheater is the air side, the hot end of the rotary air preheater is provided with a first sealing fan plate and a second sealing fan plate, the first sealing fan plate and the second sealing fan plate are both located between the air side and the flue gas side, and the first sealing fan plate and the second sealing fan plate are both provided with air inlets; The cold end of the rotary air preheater is provided with a third sealing sector plate and a fourth sealing sector plate, the third sealing sector plate and the fourth sealing sector plate are both located between the air side and the flue gas side, and the third sealing sector plate and the fourth sealing sector plate are both provided with air inlets; The inlet of the first hot flue gas branch pipeline is communicated with the main flue at the air preheater inlet, and the outlet of the first hot flue gas branch pipeline is communicated with the air inlet on the first sealing sector plate; the inlet of the second hot flue gas branch pipeline is communicated with the main flue at the air preheater inlet, and the outlet of the second hot flue gas branch pipeline is communicated with the air inlet on the second sealing sector plate; The inlet of the first cold smoke gas branch pipeline is connected to the main flue at the dust collector outlet, and the outlet of the first cold smoke gas branch pipeline is connected to the air inlet on the third sealing fan-shaped plate; the inlet of the second cold smoke gas branch pipeline is connected to the main flue at the dust collector outlet, and the outlet of the second cold smoke gas branch pipeline is connected to the air inlet on the fourth sealing fan-shaped plate.

2. The rotary air preheater sealing system according to claim 1, characterized in that: The rotary air preheater sealing system also includes a first fan and a second fan; The first fan is arranged on the first hot flue gas branch pipe, and the second fan is arranged on the second hot flue gas branch pipe.

3. The rotary air preheater sealing system according to claim 2, characterized in that: The rotary air preheater sealing system also includes a first pressure detection device, a second pressure detection device, a third pressure detection device and a fourth pressure detection device; The first pressure detection device is arranged under the first sealing sector plate, and the second pressure detection device is arranged on the air side of the hot end of the rotary air preheater; The third pressure detection device is arranged under the second sealing sector plate, and the fourth pressure detection device is arranged on the air side of the hot end of the rotary air preheater.

4. The rotary air preheater sealing system according to claim 3, characterized in that: The rotary air preheater sealing system also includes a third fan and a fourth fan; The third fan is arranged on the first cold flue gas branch pipe, and the fourth fan is arranged on the second cold flue gas branch pipe.

5. The rotary air preheater sealing system according to claim 4, characterized in that: The rotary air preheater sealing system also includes a fifth pressure detection device, a sixth pressure detection device, a seventh pressure detection device and an eighth pressure detection device; The fifth pressure detection device is arranged under the third sealing sector plate, and the sixth pressure detection device is arranged on the air side of the cold end of the rotary air preheater; The seventh pressure detection device is arranged under the fourth sealing sector plate, and the eighth pressure detection device is arranged on the air side of the cold end of the rotary air preheater.

6. The rotary air preheater sealing system according to claim 5, characterized in that: The rotary air preheater sealing system also includes a control server; The first fan, the second fan, the third fan, the fourth fan, the first pressure detection device, the second pressure detection device, the third pressure detection device, the fourth pressure detection device, the fifth pressure detection device, the sixth pressure detection device, the seventh pressure detection device and the eighth pressure detection device are all connected to the control server.

7. The rotary air preheater sealing system according to claim 2, characterized in that: The rotary air preheater sealing system also includes a first inlet valve, a second inlet valve, a first outlet valve and a second outlet valve; The first inlet valve and the first outlet valve are both arranged on the first hot flue gas branch pipeline, the first inlet valve is located upstream of the first fan, and the first outlet valve is located downstream of the first fan; The second inlet valve and the second outlet valve are both arranged on the second hot flue gas branch pipeline, the second inlet valve is located upstream of the second fan, and the second outlet valve is located downstream of the second fan.

8. The rotary air preheater sealing system according to claim 4, characterized in that: The rotary air preheater sealing system also includes a third inlet valve, a fourth inlet valve, a third outlet valve and a fourth outlet valve; The third inlet valve and the third outlet valve are both arranged on the first cold flue gas branch pipeline, the third inlet valve is located upstream of the third fan, and the third outlet valve is located downstream of the third fan; The fourth inlet valve and the fourth outlet valve are both arranged on the second cold flue gas branch pipeline, the fourth inlet valve is located upstream of the fourth fan, and the fourth outlet valve is located downstream of the fourth fan.

9. The rotary air preheater sealing system according to claim 1, characterized in that: The first sealing sector plate, the second sealing sector plate, the third sealing sector plate and the fourth sealing sector plate are all provided with a plurality of air inlets; Along the smoke flow direction, the opening size of each air inlet on the first sealing sector plate and the opening size of each air inlet on the second sealing sector plate gradually decrease; Along the smoke flow direction, the opening size of each air inlet on the third sealing sector plate and the opening size of each air inlet on the fourth sealing sector plate gradually increase.

10. The rotary air preheater sealing system according to claim 1, characterized in that: The air side is divided into a primary air side and a secondary air side; the first sealing fan plate is located between the primary air side and the smoke side, the second sealing fan plate is located between the secondary air side and the smoke side, the third sealing fan plate is located between the primary air side and the smoke side, and the fourth sealing fan plate is located between the secondary air side and the smoke side.

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