Rotary air preheater and boiler

Abstract

The utility model discloses a rotary air preheater which comprises a preheater body, a smoke side branch bin, a primary air branch bin, a secondary air branch bin and a hot air heating channel, the smoke side branch bin, the primary air branch bin, the secondary air branch bin and the hot air heating channel are arranged around the center of the preheater body, and the hot air heating channel is arranged between the primary air branch bin and the secondary air branch bin. And air preheated by the flue gas is introduced into the flue gas inlet. The utility model further provides a boiler. The air pre-heater can avoid ammonium bisulfate deposition and solve the problem of blockage of the air pre-heater.

Description

Technical Field

[0001] The utility model relates to the technical field related to boilers, and more specifically, to a rotary air preheater and a boiler. Background Art

[0002] At present, most power plant boilers are equipped with denitrification devices. However, the escaped ammonia of the denitrification device easily reacts with SO3 in the flue gas to form ammonium bisulfate. Ammonium bisulfate is a liquid between 147-207 ℃ and is easy to adhere to the heat exchange elements of the air preheater (rotary air preheater), causing the air preheater to be blocked. When the air preheater is blocked, the resistance on the flue gas side will be greatly increased, the output of the induced draft fan will be increased, and the power consumption rate of the power plant will be increased; at the same time, the air preheater will be seriously affected in terms of heat exchange capacity, and the exhaust gas temperature at the outlet of the air preheater will be greatly increased, which will have an adverse effect on the thermal efficiency of the boiler.

[0003] At present, most power plant boilers use the following methods to solve the problem of air preheater blockage: 1) The rotary air preheater adopts a two-stage layout, that is, only a high-temperature section and a low-temperature section are set, the medium-temperature section is eliminated, and the height of the low-temperature section is increased as much as possible, so that ammonium bisulfate is deposited in the low-temperature section. At the same time, the heat exchange element of the low-temperature section adopts the enamel plating process. 2) The inlet of the rotary air preheater adopts a steam heater or hot air recirculation to increase the cold air temperature at the inlet of the air preheater.

[0004] The above-mentioned conventional solutions cannot fundamentally solve the problem of air preheater blockage, especially for boilers burning high-sulfur coal, where the SO3 content in the flue gas is higher and the ammonium bisulfate blockage problem is more serious. Utility Model Content

[0005] One purpose of the utility model is to provide a rotary air preheater and a boiler, which can avoid the deposition of ammonium bisulfate and solve the problem of air preheater blockage.

[0006] In order to achieve these purposes and other advantages of the utility model, according to one aspect of the utility model, a rotary air preheater is provided, including a preheater body and a flue gas side compartment, a primary air compartment, a secondary air compartment and a hot air heating channel arranged around the center of the preheater body, and the hot air heating channel is arranged between the primary air compartment and the secondary air compartment for passing air preheated by the flue gas.

[0007] Furthermore, it also includes: a flue gas heater, which has a flue gas flow duct and an air flow duct, the inlet of the flue gas flow duct is connected to the air preheater inlet flue through a flue gas diverter pipe, the inlet of the air flow duct is connected to the cold primary air duct of the air preheater through an air diverter pipe, and the outlet of the air flow duct is connected to the inlet of the hot air heating channel.

[0008] Furthermore, the outlet of the hot air heating channel is connected to the hot secondary air duct of the air preheater.

[0009] Furthermore, the smoke diversion pipe and the air diversion pipe are both provided with air volume measuring elements and regulating valves.

[0010] Furthermore, thermocouples are respectively arranged at or near the inlet and outlet of the flue gas flow passage and at or near the inlet and outlet of the air flow passage.

[0011] Furthermore, the smoke side compartment, the primary air compartment, the secondary air compartment and the hot air heating channel are separated by fan-shaped plates.

[0012] According to another aspect of the utility model, a rotary air preheater is provided, comprising a preheater body, a flue gas heater, and a flue gas side compartment, a primary air compartment, a secondary air compartment and a hot air heating channel arranged around the center of the preheater body, wherein the hot air heating channel is arranged between the primary air compartment and the secondary air compartment, and the flue gas heater has a flue gas flow channel and an air flow channel, wherein the inlet of the flue gas flow channel is connected to the inlet flue of the air preheater through a flue gas diverter pipe, the inlet of the air flow channel is connected to the cold primary air duct of the air preheater through an air diverter pipe, the outlet of the air flow channel is connected to the inlet of the hot air heating channel, and the outlet of the hot air heating channel is connected to the hot secondary air duct of the air preheater.

[0013] Furthermore, the flue gas diversion pipe and the air diversion pipe are both provided with air volume measuring elements and regulating valves, and thermocouples are respectively provided at or near the inlet and outlet of the flue gas flow passage and at or near the inlet and outlet of the air flow passage.

[0014] Furthermore, the smoke side compartment, the primary air compartment, the secondary air compartment and the hot air heating channel are separated by fan-shaped plates.

[0015] According to one aspect of the utility model, a boiler is provided, comprising the rotary air preheater.

[0016] The utility model at least has the following beneficial effects:

[0017] The utility model sets a hot air heating channel between the primary air compartment and the secondary air compartment, and introduces air preheated by flue gas. The hot air heating channel can utilize a small amount of hot air to frequently heat each part of the air preheater heat exchange element, thereby increasing the cold end temperature and putting the ammonium bisulfate in a gasified state, thus avoiding the deposition of ammonium bisulfate on the cold end and solving the problem of air preheater blockage.

[0018] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the utility model;

[0020] Figure 2 It is a framework diagram of the utility model. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0022] It should be understood that the terms such as "having", "including" and "comprising" used in the embodiments of the present application do not exclude the existence or addition of one or more other elements or their combinations. All directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative position relationship, movement, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly. When an element is referred to as "fixed on" or "set on" another element, it can be directly on the other element or there may be a centering element at the same time. When an element is referred to as "connecting" another element, it can be directly connected to another element or it can be indirectly connected to another element through a centering element. The description of "first", "second", etc. in the embodiments of the present application is only for descriptive purposes, and cannot be understood as indicating or implying its relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features.

[0023] It should be noted that the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. 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.

[0024] like Figure 1 , 2As shown, an embodiment of the present application provides a rotary air preheater, comprising a preheater body 1, a preheater body 11 and a flue gas side compartment 6, a primary air compartment 2, a secondary air compartment 3 and a hot air heating channel 4 arranged around the center of the preheater body 1, the hot air heating channel 4 is arranged between the primary air compartment 2 and the secondary air compartment 3, and is used to pass air preheated by flue gas through an air duct 14; the preheated air has a higher temperature, which can heat the heat exchange element rotating in the preheater body 1, the preheater body 11, and increase the cold end temperature so that the cold end temperature is always higher than the gasification temperature of ammonium bisulfate, thereby avoiding the deposition of ammonium bisulfate on the cold end and solving the problem of air preheater blockage.

[0025] Exemplarily, the preheater body 1 preheater body 11 includes a shell, a rotor, a heat exchange element, an inlet flue, an outlet flue, a cold primary air duct 15, a cold secondary air duct 16, a hot primary air duct and a hot secondary air duct. The heat exchange element is arranged on the rotor and is located inside the shell. The heat exchange element can rotate with the rotor. The inlet flue and the outlet flue are respectively used for the flue gas to flow into and out of the shell, the cold primary air duct 15 and the hot primary air duct are respectively used for the primary air to flow into and out of the shell, the cold secondary air duct 16 and the hot secondary air duct are respectively used for the secondary air to flow into and out of the shell, and the flue gas heats the primary air and the secondary air through the rotational heat transfer of the heat exchange element, and then used for boiler operation.

[0026] Exemplarily, the separation of the smoke side compartment 6 , the primary air compartment 2 , the secondary air compartment 3 and the hot air heating channel 4 is achieved by the fan-shaped plate 5 .

[0027] Exemplarily, the preheated air needs to reach a temperature above 207° C. to gasify the ammonium bisulfate.

[0028] Exemplarily, the size of the hot air heating channel 4 is smaller than the size of the primary air compartment 2 and the secondary air compartment 3, such as half the size of the secondary air compartment, so as to reduce the impact on the primary and secondary air preheating processes, reduce the waste of hot air, and increase the flow rate of the hot air in the hot air heating channel 4, so that the hot air can quickly heat all parts of the rotating heat exchange element.

[0029] Exemplarily, the air flow rate in the hot air heating channel 4 matches the rotation speed of the rotor, ensuring that each rotation of the heating element can cause each part to be heated by the hot air, ensuring that each part of the heat exchange element is not blocked.

[0030] In this embodiment, the hot air heating channel 4 is arranged between the primary air compartment 2 and the secondary air compartment 3. Compared with being arranged outside the primary air compartment 2 and the secondary air compartment 3, it can avoid the hot air from leaking into the flue gas side compartment 6 due to the high wind pressure of the hot air heating channel 4 and the low flue gas wind pressure, thereby affecting the gasification effect of ammonium bisulfate.

[0031] This embodiment can be used for a newly built boiler system, that is, the rotary air preheater of this embodiment is used to replace the traditional air preheater to ensure that the heat exchange element is not blocked. It can also be used for a modified boiler system, that is, a fan-shaped plate 5 is added between the primary air bin and the secondary air bin of the traditional air preheater to separate the hot air heating channel 4, so as to achieve the control of the blockage of the heat exchange element.

[0032] In another embodiment, it also includes: a flue gas heater, which has a flue gas flow duct and an air flow duct, the inlet of the flue gas flow duct is connected to the air preheater inlet flue through a flue gas diverter pipe 12, the inlet of the air flow duct is connected to the cold primary air duct 15 of the air preheater through an air diverter pipe 13, and the outlet of the air flow duct is connected to the inlet of the hot air heating channel 4 through an air duct 14.

[0033] For example, the flue gas heater can be a tubular heat exchanger, with the inside and outside of the tube serving as a flue gas flow channel and an air flow channel respectively, to achieve preheating of the air. The flue gas heat exchanger can also be a plate heat exchanger or a plate-tooth heat exchanger.

[0034] In this embodiment, a small amount of cold primary air is taken through the air diversion pipe 13, and a part of the flue gas is taken through the flue gas diversion pipe 12 to preheat it. There is no need to add an additional air introduction system and heating system. The structure is simple and easy to be used to transform the existing boiler system.

[0035] In another embodiment, the outlet of the hot air heating channel 4 is connected to the hot secondary air duct of the air preheater; since the cold primary air pressure head is much larger than the secondary air pressure head, this embodiment can ensure that the cold primary air can be extracted smoothly without the need for an additional fan system.

[0036] In another embodiment, the flue gas diversion pipe 12 and the air diversion pipe 13 are both provided with an air volume measuring element 11 and a regulating valve 10; the air volume measuring element 11 is used to detect the flue gas volume and air volume of the flue gas diversion pipe 12 and the air diversion pipe 13, and the regulating valve 10 is used to adjust them so that the extracted flue gas and air can meet the heating requirements of various parts of the heat exchange element.

[0037] Exemplarily, tests and calculations are conducted in advance based on the size of the heat exchange element, the size of the hot air heating channel 4, and the set air temperature in the hot air heating channel 4 to determine the amount of flue gas and air entering the air preheater and their range of change, so that during actual operation, adjustments are made by adjusting the valve 10 to ensure the heating effect on the heat exchange element.

[0038] In another embodiment, thermocouples 9 are respectively provided at or near the inlet and outlet of the flue gas flow duct and the inlet and outlet of the air flow duct; the temperature of the flue gas entering and leaving the air preheater and the temperature of the air entering the air preheater are detected in real time by the thermocouples 9 to prevent the air temperature from dropping to a level that makes it impossible to gasify the ammonium bisulfate.

[0039] An embodiment of the present application provides a rotary air preheater, comprising a preheater body 1, a preheater body 11, a flue gas heater, and a flue gas side compartment 6, a primary air compartment 2, a secondary air compartment 3 and a hot air heating channel 4 arranged around the center of the preheater body 1, the hot air heating channel 4 is arranged between the primary air compartment 2 and the secondary air compartment 3, the flue gas heater has a flue gas flow channel and an air flow channel, the inlet of the flue gas flow channel is connected to the air preheater inlet flue through a flue gas diverter pipe 12, the inlet of the air flow channel is connected to the cold primary air duct of the air preheater through an air diverter pipe 13, the outlet of the air flow channel is connected to the inlet of the hot air heating channel 4, the outlet of the hot air heating channel 4 is connected to the hot secondary air duct of the air preheater, and enters the boiler burner together with the hot secondary air.

[0040] In this embodiment, a small part of the cold primary air is taken by the air diversion pipe 13, and a part of the flue gas is taken by the flue gas diversion pipe 12 to preheat the air extracted from the cold primary air. The preheated air has a higher temperature and can heat the heat exchange element rotating in the preheater body 1 and the preheater body 11, thereby increasing the cold end temperature so that the cold end temperature is always higher than the gasification temperature of ammonium bisulfate, thereby avoiding the deposition of ammonium bisulfate on the cold end and solving the problem of air preheater blockage. There is no need to add an additional air introduction system and heating system, the structure is simple, and it is easy to be used to transform the existing boiler system.

[0041] In another embodiment, the flue gas diversion pipe 12 and the air diversion pipe 13 are both provided with an air volume measuring element 11 and a regulating valve 10, and the inlet and outlet of the flue gas flow passage or the vicinity thereof, and the inlet and outlet of the air flow passage or the vicinity thereof are respectively provided with a thermocouple 9. The air volume measuring element 11 is used to detect the flue gas volume and the air volume of the flue gas diversion pipe 12 and the air diversion pipe 13, and the regulating valve 10 is used to adjust the volume, so that the extracted flue gas and air can meet the heating of various parts of the heat exchange element, and the temperature of the flue gas entering and leaving the air preheater and the temperature of the air entering the air preheater are detected in real time by the thermocouple 9, so as to prevent the air temperature from dropping to the point where the ammonium bisulfate cannot be gasified.

[0042] In another embodiment, the smoke side compartment 6 , the primary air compartment 2 , the secondary air compartment 3 and the hot air heating channel 4 are separated by a fan-shaped plate 5 .

[0043] An embodiment of the present application also provides a boiler, including the rotary air preheater of the above embodiment, which can utilize the hot air heating channel 4 arranged between the primary air compartment 2 and the secondary air compartment 3 to heat the heat exchange element rotating in the preheater body 1 and the preheater body 11, thereby increasing the cold end temperature so that the cold end temperature is always higher than the gasification temperature of ammonium bisulfate, thereby avoiding the deposition of ammonium bisulfate on the cold end and solving the problem of air preheater blockage.

[0044] The number of equipment and processing scale described here are used to simplify the description of the utility model. The application, modification and variation of the rotary air preheater of the utility model are obvious to those skilled in the art.

[0045] Although the implementation scheme of the utility model has been disclosed as above, it is not limited to the applications listed in the specification and implementation modes. It can be fully applied to various fields suitable for the utility model. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. Rotary air preheater, characterized in that: It includes a preheater body and a flue gas side compartment, a primary air compartment, a secondary air compartment and a hot air heating channel arranged around the center of the preheater body. The hot air heating channel is arranged between the primary air compartment and the secondary air compartment for introducing air preheated by flue gas.

2. The rotary air preheater according to claim 1, characterized in that: Also includes: The flue gas heater comprises a flue gas flow channel and an air flow channel. The inlet of the flue gas flow channel is connected to the inlet flue of the air preheater through a flue gas diverter pipe, the inlet of the air flow channel is connected to the cold primary air duct of the air preheater through an air diverter pipe, and the outlet of the air flow channel is connected to the inlet of the hot air heating channel.

3. The rotary air preheater according to claim 2, characterized in that: The outlet of the hot air heating channel is connected to the hot secondary air duct of the air preheater.

4. The rotary air preheater according to claim 2, characterized in that: The smoke diversion pipe and the air diversion pipe are both provided with air volume measuring elements and regulating valves.

5. The rotary air preheater according to claim 2, characterized in that: Thermocouples are respectively arranged at or near the inlet and outlet of the flue gas flow passage and at or near the inlet and outlet of the air flow passage.

6. The rotary air preheater according to claim 2, characterized in that: The smoke side compartment, the primary air compartment, the secondary air compartment and the hot air heating channel are separated by fan-shaped plates.

7. Rotary air preheater, characterized in that: It includes a preheater body, a flue gas heater, and a flue gas side compartment, a primary air compartment, a secondary air compartment and a hot air heating channel arranged around the center of the preheater body. The hot air heating channel is arranged between the primary air compartment and the secondary air compartment. The flue gas heater has a flue gas flow channel and an air flow channel. The inlet of the flue gas flow channel is connected with the air preheater inlet flue through a flue gas diverter pipe, the inlet of the air flow channel is connected with the cold primary air duct of the air preheater through an air diverter pipe, the outlet of the air flow channel is connected with the inlet of the hot air heating channel, and the outlet of the hot air heating channel is connected to the hot secondary air duct of the air preheater.

8. The rotary air preheater according to claim 7, characterized in that: The flue gas diversion pipe and the air diversion pipe are both provided with air volume measuring elements and regulating valves, and thermocouples are respectively provided at or near the inlet and outlet of the flue gas flow passage and at or near the inlet and outlet of the air flow passage.

9. The rotary air preheater according to claim 7, characterized in that: The smoke side compartment, the primary air compartment, the secondary air compartment and the hot air heating channel are separated by fan-shaped plates.

10. A boiler, characterized in that It comprises the rotary air preheater described in any one of claims 1-9.

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