A primary air heating system for a waste incineration power plant

Abstract

The present invention discloses a primary air heating system for a waste incineration power plant, including a steam heating primary air system and a flue gas heating primary air system. The flue gas heating primary air system includes a plurality of flue gas air heat exchange systems sequentially connected along the flow direction of cold primary air or primary air, and the positions of the steam heating primary air system and the flue gas heating primary air system are selectively interchanged according to the flow direction of the primary air. The present invention provides a primary air heating system for a waste incineration power plant. When the steam heating primary air system fails or needs to be repaired, the flue gas heating primary air system can continue to work, and the steam-air preheater can be repaired without stopping the furnace, without affecting the heating of the cold primary air. The appropriate cold primary air heating mode can also be selected according to the calorific value of the waste, and it is suitable for burning waste fuels of various calorific values.

Description

Technical Field

[0001] The invention belongs to the technical field of waste incineration, and in particular relates to a primary air heating system of a waste incineration power station. Background Art

[0002] In waste incineration power plants, the primary air is generally heated only by a steam-air preheater. However, when the calorific value of the waste is lower than the design value, although the primary air temperature at the steam-air preheater outlet can reach the design air temperature, it is still difficult to maintain stable combustion in the incineration boiler.

[0003] High-temperature flue gas-air preheater is a primary air heating device that uses high-temperature flue gas from waste heat boiler as heat source. After long-term operation of the unit, due to coking in the incineration boiler, the flue gas temperature at the inlet of the heating surface of the waste heat boiler equipment is higher than the design value, which is very prone to high-temperature corrosion.

[0004] In order to make full use of the high-temperature flue gas in the waste heat boiler to slow down the coking and high-temperature corrosion of the heating surface of the waste heat boiler, and to increase the air temperature of the primary air heating system to ensure stable combustion of the unit when the calorific value of the garbage is lower than the design value, the present invention proposes a new system that combines the use of a steam-air preheater and a high-temperature flue gas-air preheater. Summary of the invention

[0005] In order to solve the problems in the prior art, the object of the present invention is to provide a primary air heating system for a waste incineration power plant.

[0006] In order to achieve the above purpose and the above technical effect, the technical solution adopted by the present invention is:

[0007] A primary air heating system for a waste incineration power plant comprises a steam heating primary air system and a flue gas heating primary air system. The flue gas heating primary air system comprises a plurality of flue gas-air heat exchange systems sequentially connected along the flow direction of cold primary air or primary air. The positions of the steam heating primary air system and the flue gas heating primary air system are selectively interchanged according to the flow direction of the primary air.

[0008] Furthermore, the steam-heated primary air system includes a steam-air preheater, a main regulating valve and a bypass regulating valve. The main regulating valve is connected in series with the steam-air preheater and is arranged sequentially along the flow direction of the cold primary air or the primary air. The main regulating valve is connected in parallel with the bypass regulating valve.

[0009] Furthermore, the flue gas heating primary air system includes a fourth flue gas-air heat exchange system, a third flue gas-air heat exchange system, a second flue gas-air heat exchange system and a first flue gas-air heat exchange system which are sequentially connected along the flow direction of the cold primary air or the primary air.

[0010] Furthermore, the fourth flue gas-air heat exchange system includes a fourth bypass regulating valve and an eighth main regulating valve, a fourth flue gas-air heat exchanger and a seventh main regulating valve which are sequentially arranged and connected along the primary air flow direction. The fourth bypass regulating valve is connected in parallel with the eighth main regulating valve. External cold primary air or cold primary air from a steam heating primary air system is injected into the inlet of the fourth flue gas-air heat exchanger through the eighth main regulating valve. The outlet of the fourth flue gas-air heat exchanger is connected to between the fourth bypass regulating valve and the third flue gas-air heat exchange system through the seventh main regulating valve.

[0011] Furthermore, the third flue gas-air heat exchange system includes a third bypass regulating valve and a sixth main regulating valve, a third flue gas-air heat exchanger 7 and a fifth main regulating valve which are sequentially arranged and connected along the primary air flow direction, and the third bypass regulating valve is connected in parallel with the sixth main regulating valve.

[0012] Furthermore, the second flue gas-air heat exchange system includes a second bypass regulating valve and a fourth main regulating valve, a second flue gas-air heat exchanger and a third main regulating valve which are sequentially arranged and connected along the primary air flow direction, and the second bypass regulating valve is connected in parallel with the fourth main regulating valve.

[0013] Furthermore, the first flue gas-air heat exchange system includes a first bypass regulating valve and a second main regulating valve, a first flue gas-air heat exchanger and a first main regulating valve which are sequentially arranged and connected along the primary air flow direction, and the first bypass regulating valve is connected in parallel with the second main regulating valve.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention discloses a primary air heating system for a waste incineration power plant, including a steam heating primary air system and a flue gas heating primary air system. The flue gas heating primary air system includes a plurality of flue gas-air heat exchange systems sequentially connected along the flow direction of cold primary air or primary air. The positions of the steam heating primary air system and the flue gas heating primary air system are selectively interchanged according to the flow direction of the primary air. In the primary air heating system for a waste incineration power plant provided by the present invention, when the steam heating primary air system fails or needs to be repaired, the flue gas heating primary air system can still continue to work, and the steam-air preheater can be repaired without stopping the furnace, without affecting the heating of the cold primary air, and a suitable cold primary air heating mode can be selected according to the calorific value of the waste, which is suitable for burning waste fuels of various calorific values. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0017] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0018] Among them, 1-steam heating primary air system, 11-steam-air preheater, 12-main road regulating valve, 13-bypass regulating valve, 2-flue gas heating primary air system, 21-fourth flue gas-air heat exchange system, 22-third flue gas-air heat exchange system, 23-second flue gas-air heat exchange system, 24-first flue gas-air heat exchange system, 211-fourth bypass regulating valve, 212-seventh main road regulating valve, 213-eighth main road regulating valve, 221-third bypass regulating valve, 2 22-fifth main line regulating valve, 223-sixth main line regulating valve, 231-second bypass regulating valve, 232-third main line regulating valve, 233-fourth main line regulating valve, 241-first bypass regulating valve, 242-first main line regulating valve, 243-second main line regulating valve, 3-first flue gas-air heat exchanger, 4-evaporator, 5-second flue gas-air heat exchanger, 6-superheater, 7-third flue gas-air heat exchanger, 8-economizer, 9-fourth flue gas-air heat exchanger. DETAILED DESCRIPTION

[0019] The present invention is described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0020] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0021] In the description of the present invention, it should be noted that the terms "upper", "lower", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0022] like Figure 1-2As shown, a primary air heating system of a waste incineration power plant includes a steam heating primary air system 1 and a flue gas heating primary air system 2, and the positions of the two are selectively interchanged according to the primary air flow direction. The steam heating primary air system 1 includes a steam-air preheater 11, a main regulating valve 12 and a bypass regulating valve 13. The main regulating valve 12 is connected in series with the steam-air preheater 11 and is arranged in sequence along the cold primary air or primary air flow direction. The main regulating valve 12 is connected in parallel with the bypass regulating valve 13. The flue gas heating primary air system 2 includes a steam-air preheater 11, a main regulating valve 12 and a bypass regulating valve 13. or a fourth flue gas-air heat exchange system 21, a third flue gas-air heat exchange system 22, a second flue gas-air heat exchange system 23 and a first flue gas-air heat exchange system 24 which are sequentially connected in the primary air flow direction, the fourth flue gas-air heat exchange system 21, the third flue gas-air heat exchange system 22, the second flue gas-air heat exchange system 23 and the first flue gas-air heat exchange system 24 respectively including a flue gas-air heat exchanger, the fourth flue gas-air heat exchange system 21 including a fourth bypass regulating valve 211 and a third flue gas-air heat exchange system 22 which are sequentially arranged and connected in the primary air flow direction The eighth main regulating valve 213, the fourth flue gas-air heat exchanger 9 and the seventh main regulating valve 212, the fourth bypass regulating valve 211 is connected in parallel with the eighth main regulating valve 213, the third flue gas-air heat exchanger 22 includes the third bypass regulating valve 221 and the sixth main regulating valve 223, the third flue gas-air heat exchanger 7 and the fifth main regulating valve 222 which are sequentially arranged and connected along the primary air flow direction, the third bypass regulating valve 221 is connected in parallel with the sixth main regulating valve 223, the second flue gas-air heat exchanger 23 includes the second bypass regulating valve 221 and the sixth main regulating valve 223, the third flue gas-air heat exchanger 7 and the fifth main regulating valve 222. The throttle valve 231 and the fourth main regulating valve 233, the second flue gas-air heat exchanger 5 and the third main regulating valve 232 are sequentially arranged and connected along the primary air flow direction, the second bypass regulating valve 231 is connected in parallel with the fourth main regulating valve 233, the first flue gas-air heat exchanger 3 and the first main regulating valve 242 are sequentially arranged and connected along the primary air flow direction, and the first bypass regulating valve 241 is connected in parallel with the second main regulating valve 243.

[0023] According to the actual calorific value of the garbage, the cold primary air can first enter the steam heating primary air system 1 and then enter the fourth flue gas-air heat exchange system 21, the third flue gas-air heat exchange system 22, the second flue gas-air heat exchange system 23 and the first flue gas-air heat exchange system 24 in sequence to obtain hot primary air and discharge it. At this time, the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are closed, and the other regulating valves are opened; the cold primary air can also first enter the steam heating primary air system 1 and then directly discharge it through the pipeline connected to the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 in sequence. At this time, only the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are opened, and the other regulating valves are closed; in other words, The cold primary air may also first enter the pipeline connected by the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 according to the actual calorific value of the garbage, and then enter the steam heating primary air system 1 and then be discharged. At this time, only the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are opened, and the other regulating valves are closed; the cold primary air may also first enter the fourth flue gas-air heat exchange system 21, the third flue gas-air heat exchange system 22, the second flue gas-air heat exchange system 23 and the first flue gas-air heat exchange system 24 in sequence and then be discharged through the steam heating primary air system 1. At this time, the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are closed, and the other regulating valves are opened; the flue gas after heat exchange can be discharged directly.

[0024] Cold primary air or primary air from the steam heating primary air system 1 is injected into the inlet of the fourth flue gas-air heat exchanger 9 through the eighth main regulating valve 213, and the outlet of the fourth flue gas-air heat exchanger 9 is connected to the fourth bypass regulating valve 211 and the third flue gas air heat exchange system 22 through the seventh main regulating valve 212.

[0025] The flue gas heating primary air system includes a fourth flue gas-air heat exchange system 21, a third flue gas-air heat exchange system 22, a second flue gas-air heat exchange system 23 and a first flue gas-air heat exchange system 24. During actual operation, part of the main flue gas-air heat exchange system and part of the flue gas-air heat exchange system bypass can be selectively opened according to the primary air temperature.

[0026] All regulating valves involved in the present invention can realize the function of opening or closing electrically or manually, thereby opening or closing the corresponding pipelines.

[0027] When the steam heating primary air system 1 fails or needs maintenance, the flue gas heating primary air system 2 can continue to work.

[0028] The working modes of the evaporator EVA 4, the superheater SH 6 and the economizer ECO 8 may be based on the prior art and will not be described in detail here.

[0029] Example 1

[0030] like Figure 1 As shown, a primary air heating system of a waste incineration power plant includes a steam heating primary air system 1 and a flue gas heating primary air system 2. The steam heating primary air system 1 includes a steam-air preheater 11, a main regulating valve 12 and a bypass regulating valve 13. The main regulating valve 12 is connected in series with the steam-air preheater 11 and arranged in sequence along the flow direction of the cold primary air or the primary air. The main regulating valve 12 is connected in parallel with the bypass regulating valve 13. The flue gas heating primary air system 2 includes a fourth flue gas heating valve 13 connected in sequence along the flow direction of the cold primary air or the primary air. -air heat exchange system 21, the third flue gas-air heat exchange system 22, the second flue gas-air heat exchange system 23 and the first flue gas-air heat exchange system 24, the fourth flue gas-air heat exchange system 21, the third flue gas-air heat exchange system 22, the second flue gas-air heat exchange system 23 and the first flue gas-air heat exchange system 24 respectively include a flue gas-air heat exchanger, the fourth flue gas-air heat exchange system 21 includes a fourth bypass regulating valve 211 and an eighth main regulating valve 213 sequentially arranged and connected along the primary air flow direction, The fourth flue gas-air heat exchanger 9 and the seventh main regulating valve 212, the fourth bypass regulating valve 211 and the eighth main regulating valve 213 are connected in parallel, the third flue gas-air heat exchange system 22 includes the third bypass regulating valve 221 and the sixth main regulating valve 223, the third flue gas-air heat exchanger 7 and the fifth main regulating valve 222, the third bypass regulating valve 221 and the sixth main regulating valve 223 are connected in parallel, and the second flue gas-air heat exchange system 23 includes the second bypass regulating valve 231 The fourth main regulating valve 233, the second flue gas-air heat exchanger 5 and the third main regulating valve 232 are sequentially arranged and connected along the primary air flow direction, the second bypass regulating valve 231 is connected in parallel with the fourth main regulating valve 233, the first flue gas-air heat exchanger 3 and the first main regulating valve 242 are sequentially arranged and connected along the primary air flow direction, and the first bypass regulating valve 241 is connected in parallel with the second main regulating valve 243.

[0031] According to the actual calorific value of the garbage, the cold primary air can first enter the steam heating primary air system 1 and then enter the fourth flue gas-air heat exchange system 21, the third flue gas-air heat exchange system 22, the second flue gas-air heat exchange system 23 and the first flue gas-air heat exchange system 24 in sequence to obtain hot primary air and discharge it. At this time, the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are closed, and the other regulating valves are opened; there is also a working mode in which the cold primary air first enters the steam heating primary air system 1 and then is directly discharged through the pipeline connected to the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 in sequence. At this time, the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are opened, and the other regulating valves are closed.

[0032] Cold primary air or primary air from the steam heating primary air system 1 is injected into the inlet of the fourth flue gas-air heat exchanger 9 through the eighth main regulating valve 213, and the outlet of the fourth flue gas-air heat exchanger 9 is connected to the fourth bypass regulating valve 211 and the third flue gas air heat exchange system 22 through the seventh main regulating valve 212.

[0033] The flue gas heating primary air system includes a fourth flue gas-air heat exchange system 21, a third flue gas-air heat exchange system 22, a second flue gas-air heat exchange system 23 and a first flue gas-air heat exchange system 24. During actual operation, part of the main flue gas-air heat exchange system and part of the flue gas-air heat exchange system bypass can be selectively opened according to the primary air temperature.

[0034] All regulating valves involved in the present invention can realize the function of opening or closing electrically or manually, thereby opening or closing the corresponding pipelines.

[0035] When the steam heating primary air system 1 fails or needs maintenance, the flue gas heating primary air system 2 can continue to work.

[0036] The working modes of the evaporator EVA 4, the superheater SH 6 and the economizer ECO 8 may be based on the prior art and will not be described in detail here.

[0037] The working principle of the present invention is:

[0038] When the calorific value of the garbage is much lower than the design value, the bypass regulating valve 13, the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are closed, and the main regulating valve 12 is opened. At this time, the eighth main regulating valve 213, the seventh main regulating valve 212, the sixth main regulating valve 223, the fifth main regulating valve 222, the fourth main regulating valve 233, the third main regulating valve 232, the second main regulating valve 243 and the first main regulating valve 242 are opened, and the cold primary air first passes through the main regulating valve 12 to enter the steam-air preheater 11 for heating, and then passes through the opened eighth main regulating valve 213 to enter the fourth flue gas-air heat exchanger 9 for heat exchange, and then passes through the third flue gas-air heat exchanger 7, the second flue gas-air heat exchanger 5 and the first flue gas-air heat exchanger 3 in sequence for four-stage heating and heat exchange to become hot primary air, and then discharged to the furnace;

[0039] When the calorific value of the garbage is close to or higher than the design value, the main regulating valve 12, the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are opened, and the bypass regulating valve 13 and other regulating valves are closed. The cold primary air is heated by the steam-air preheater 11 of the steam-heated primary air system 1 and then discharged directly through the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 without passing through the fourth flue gas-air heat exchanger 9, the third flue gas-air heat exchanger 7, the second flue gas-air heat exchanger 5 and the first flue gas-air heat exchanger 3 for heat exchange; there is also a working mode in which the main regulating valve 12, the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are opened, and the bypass regulating valve 13 and other regulating valves are closed. The regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are closed, and the bypass regulating valve 13, the eighth main regulating valve 213, the seventh main regulating valve 212, the sixth main regulating valve 223, the fifth main regulating valve 222, the fourth main regulating valve 233, the third main regulating valve 232, the second main regulating valve 243 and the first main regulating valve 242 are opened. At this time, the cold primary air directly passes through the bypass regulating valve 13 and the eighth main regulating valve 213 and enters the fourth flue gas-air heat exchanger 9, the third flue gas-air heat exchanger 7, the second flue gas-air heat exchanger 5 and the first flue gas-air heat exchanger 3 in turn for four-stage heating heat exchange and then enters the furnace; the flue gas after heat exchange can be directly discharged.

[0040] The flue gas heating primary air system includes a fourth flue gas-air heat exchange system 21, a third flue gas-air heat exchange system 22, a second flue gas-air heat exchange system 23 and a first flue gas-air heat exchange system 24. During actual operation, part of the main flue gas-air heat exchange system and part of the flue gas-air heat exchange system bypass can be selectively opened according to the primary air temperature.

[0041] Example 2

[0042] like Figure 2 As shown, a primary air heating system of a waste incineration power plant includes a steam heating primary air system 1 and a flue gas heating primary air system 2. The steam heating primary air system 1 includes a steam-air preheater 11, a main regulating valve 12 and a bypass regulating valve 13. The main regulating valve 12 is connected in series with the steam-air preheater 11 and arranged in sequence along the flow direction of the cold primary air or the primary air. The main regulating valve 12 is connected in parallel with the bypass regulating valve 13. The flue gas heating primary air system 2 includes a fourth flue gas heating valve 13 connected in sequence along the flow direction of the cold primary air or the primary air. -air heat exchange system 21, the third flue gas-air heat exchange system 22, the second flue gas-air heat exchange system 23 and the first flue gas-air heat exchange system 24, the fourth flue gas-air heat exchange system 21, the third flue gas-air heat exchange system 22, the second flue gas-air heat exchange system 23 and the first flue gas-air heat exchange system 24 respectively include a flue gas-air heat exchanger, the fourth flue gas-air heat exchange system 21 includes a fourth bypass regulating valve 211 and an eighth main regulating valve 213 sequentially arranged and connected along the primary air flow direction, The fourth flue gas-air heat exchanger 9 and the seventh main regulating valve 212, the fourth bypass regulating valve 211 and the eighth main regulating valve 213 are connected in parallel, the third flue gas-air heat exchange system 22 includes the third bypass regulating valve 221 and the sixth main regulating valve 223, the third flue gas-air heat exchanger 7 and the fifth main regulating valve 222, the third bypass regulating valve 221 and the sixth main regulating valve 223 are connected in parallel, and the second flue gas-air heat exchange system 23 includes the second bypass regulating valve 231 The fourth main regulating valve 233, the second flue gas-air heat exchanger 5 and the third main regulating valve 232 are sequentially arranged and connected along the primary air flow direction, the second bypass regulating valve 231 is connected in parallel with the fourth main regulating valve 233, the first flue gas-air heat exchanger 3 and the first main regulating valve 242 are sequentially arranged and connected along the primary air flow direction, and the first bypass regulating valve 241 is connected in parallel with the second main regulating valve 243.

[0043] The cold primary air may first enter the pipeline connected by the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 according to the actual calorific value of the garbage, and then enter the steam heating primary air system 1 and then be discharged. At this time, there is no need to exchange heat through the fourth flue gas-air heat exchanger 9, the third flue gas-air heat exchanger 7, the second flue gas-air heat exchanger 5 and the first flue gas-air heat exchanger 3. The fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are opened, and the other regulating valves are closed; the cold primary air The wind may also first enter the fourth flue gas-air heat exchange system 21, the third flue gas-air heat exchange system 22, the second flue gas-air heat exchange system 23 and the first flue gas-air heat exchange system 24 in sequence, undergo heat exchange through the fourth flue gas-air heat exchanger 9, the third flue gas-air heat exchanger 7, the second flue gas-air heat exchanger 5 and the first flue gas-air heat exchanger 3, and then be discharged through the steam heating primary air system 1. The flue gas after heat exchange may be discharged directly. At this time, the fourth bypass regulating valve 211, the third bypass regulating valve 221, the second bypass regulating valve 231 and the first bypass regulating valve 241 are closed, and the remaining regulating valves are opened.

[0044] Cold primary air is injected into the inlet of the fourth flue gas-air heat exchanger 9 through the eighth main regulating valve 213, and the outlet of the fourth flue gas-air heat exchanger 9 is connected to between the fourth bypass regulating valve 211 and the third flue gas air heat exchange system 22 through the seventh main regulating valve 212.

[0045] The flue gas heating primary air system includes a fourth flue gas-air heat exchange system 21, a third flue gas-air heat exchange system 22, a second flue gas-air heat exchange system 23 and a first flue gas-air heat exchange system 24. During actual operation, part of the main flue gas-air heat exchange system and part of the flue gas-air heat exchange system bypass can be selectively opened according to the primary air temperature.

[0046] All regulating valves involved in the present invention can realize the function of opening or closing electrically or manually, thereby opening or closing the corresponding pipelines.

[0047] When the steam heating primary air system 1 fails or needs maintenance, the flue gas heating primary air system 2 can continue to work.

[0048] The working modes of the evaporator EVA 4, the superheater SH 6 and the economizer ECO 8 may be based on the prior art and will not be described in detail here.

[0049] The rest is the same as in Example 1.

[0050] Parts not specifically described in the present invention may adopt existing technologies and will not be described in detail here.

[0051] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A primary air heating system for a waste incineration power plant, characterized in that: It includes a steam-heated primary air system and a flue gas-heated primary air system, wherein the flue gas-heated primary air system includes a plurality of flue gas-air heat exchange systems sequentially connected along the flow direction of the cold primary air or the primary air, and the positions of the steam-heated primary air system and the flue gas-heated primary air system are selectively interchanged according to the flow direction of the primary air; The steam-heated primary air system comprises a steam-air preheater, a main regulating valve and a bypass regulating valve, wherein the main regulating valve is connected in series with the steam-air preheater and arranged in sequence along the flow direction of the cold primary air or the primary air, and the main regulating valve is connected in parallel with the bypass regulating valve; The flue gas heating primary air system comprises a fourth flue gas-air heat exchange system, a third flue gas-air heat exchange system, a second flue gas-air heat exchange system and a first flue gas-air heat exchange system which are sequentially connected along the flow direction of the cold primary air or the primary air; The fourth flue gas-air heat exchange system comprises a fourth bypass regulating valve and an eighth main regulating valve, a fourth flue gas-air heat exchanger and a seventh main regulating valve which are sequentially arranged and connected along the primary air flow direction, the fourth bypass regulating valve is connected in parallel with the eighth main regulating valve, the inlet of the fourth flue gas-air heat exchanger is filled with external cold primary air or cold primary air from a steam heating primary air system through the eighth main regulating valve, and the outlet of the fourth flue gas-air heat exchanger is connected between the fourth bypass regulating valve and the third flue gas-air heat exchange system through the seventh main regulating valve; The third flue gas-air heat exchange system comprises a third bypass regulating valve and a sixth main regulating valve, a third flue gas-air heat exchanger and a fifth main regulating valve which are sequentially arranged and connected along the primary air flow direction, and the third bypass regulating valve is connected in parallel with the sixth main regulating valve; The second flue gas-air heat exchange system comprises a second bypass regulating valve and a fourth main regulating valve, a second flue gas-air heat exchanger and a third main regulating valve which are sequentially arranged and connected along the primary air flow direction, and the second bypass regulating valve is connected in parallel with the fourth main regulating valve; The first flue gas-air heat exchange system comprises a first bypass regulating valve and a second main regulating valve, a first flue gas-air heat exchanger and the first main regulating valve which are sequentially arranged and connected along the primary air flow direction, and the first bypass regulating valve is connected in parallel with the second main regulating valve; When the steam heating primary air system fails or needs to be repaired, the flue gas heating primary air system can still continue to work, so that the steam-air preheater can be repaired without stopping the furnace, without affecting the heating of the cold primary air. It can also select a suitable cold primary air heating mode according to the calorific value of the garbage, which is suitable for burning garbage fuels of various calorific values; When the calorific value of the garbage is far lower than the design value, the bypass regulating valve, the fourth bypass regulating valve, the third bypass regulating valve, the second bypass regulating valve and the first bypass regulating valve are closed, and the main regulating valve is opened. At this time, the eighth main regulating valve, the seventh main regulating valve, the sixth main regulating valve, the fifth main regulating valve, the fourth main regulating valve, the third main regulating valve, the second main regulating valve and the first main regulating valve are opened, and the cold primary air first passes through the main regulating valve to enter the steam-air preheater for heating, and then passes through the opened eighth main regulating valve to enter the fourth flue gas-air heat exchanger for heat exchange, and then passes through the third flue gas-air heat exchanger, the second flue gas-air heat exchanger and the first flue gas-air heat exchanger in turn for four-stage heating and heat exchange to become hot primary air, and then discharged to the furnace; When the calorific value of the garbage is close to or higher than the design value, the main regulating valve, the fourth bypass regulating valve, the third bypass regulating valve, the second bypass regulating valve and the first bypass regulating valve are opened, the bypass regulating valve and other regulating valves are closed, and the cold primary air is heated by the steam-air preheater of the steam-heated primary air system and then discharged directly through the fourth bypass regulating valve, the third bypass regulating valve, the second bypass regulating valve and the first bypass regulating valve without heat exchange through the fourth flue gas-air heat exchanger, the third flue gas-air heat exchanger, the second flue gas-air heat exchanger and the first flue gas-air heat exchanger; there is also a working mode in which the main regulating valve , the fourth bypass regulating valve, the third bypass regulating valve, the second bypass regulating valve and the first bypass regulating valve are closed, and the bypass regulating valve, the eighth main regulating valve, the seventh main regulating valve, the sixth main regulating valve, the fifth main regulating valve, the fourth main regulating valve, the third main regulating valve, the second main regulating valve and the first main regulating valve are opened. At this time, the cold primary air directly passes through the bypass regulating valve and the eighth main regulating valve and enters the fourth flue gas-air heat exchanger, the third flue gas-air heat exchanger, the second flue gas-air heat exchanger and the first flue gas-air heat exchanger in turn for four-stage heating heat exchange and then enters the furnace; the flue gas after heat exchange can be discharged directly.

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