An adjustable dual-pressure waste heat recovery system for cement kiln head

Abstract

The present invention relates to the technical field of waste heat utilization in cement production, and aims to solve the problem that the current technology is difficult to meet the requirements of the cement waste heat recovery system for waste heat recovery efficiency and system working stability, and provides an adjustable dual-pressure waste heat recovery system at the cement kiln head, which includes a grate cooler, a high-temperature dust collector, a medium-temperature dust collector, a dual-pressure AQC boiler, a dust collector, an induced draft fan, and a chimney; the grate cooler is provided with three high / medium / low temperature air intakes. The high / medium temperature air intakes enter the dual-pressure AQC boiler after passing through the high / medium temperature dust collectors respectively; the low-temperature air intake is connected to the dust collector inlet through a low-temperature regulating valve; a partition is provided in the dual-pressure AQC boiler, and the partition divides the flue gas channel into a high-temperature flue and a medium-temperature flue; the high-temperature air inlet is connected to the high-temperature dust collector through a pipeline, and the medium-temperature air inlet is connected to the medium-temperature dust collector through a pipeline. The beneficial effect of the present invention is to meet the requirements of the cement waste heat recovery system for waste heat recovery efficiency and system working stability.

Description

Technical Field

[0001] The invention relates to the technical field of waste heat utilization in cement production, and in particular to an adjustable dual-pressure waste heat recovery system at a cement kiln head. Background Art

[0002] The development and application of cement waste heat recovery technology is an important measure for energy conservation and emission reduction in the cement industry. In the existing technology, in order to utilize the waste heat of the flue gas at the head of the cement kiln to recover and generate electricity, the focus is on how to maximize the extraction of waste heat from the hot end of the grate cooler. The design of the thermal system is a very critical link, which is not only related to the recovery efficiency of the waste heat of the cement kiln system, but also related to whether it can adapt to the fluctuation of the working conditions of the cement kiln system and whether it has the technical conditions for long-term stable operation.

[0003] At present, there are two common technologies for cement waste heat recovery systems: single-pressure thermal system and dual-pressure thermal system. For the single-pressure thermal system, its characteristics are: the system structure is simple, but the heat recovery efficiency is low and the power generation capacity is low. For the dual-pressure thermal system, high-temperature flue gas is usually extracted through the high-pressure section superheater, high-pressure section evaporator, high-pressure section economizer, low-pressure section superheater, low-pressure section evaporator, and public economizer. Its characteristics and shortcomings are specifically reflected in:

[0004] 1. The double-pressure AQC boiler of the thermal system has a complex structure and more heating surfaces. The boiler is arranged in sequence, which increases the boiler height, increases the boiler flue gas resistance, and makes the boiler pipeline layout more complicated;

[0005] 2. The flue gas volume in the high-temperature section of the grate cooler is relatively small, while the flue gas volume in the low-temperature section is relatively large. Conventional designs usually extract high-temperature flue gas at one point of the grate cooler and pass it through the high-pressure section superheater, high-pressure section evaporator, high-pressure section economizer, low-pressure section superheater, low-pressure section evaporator, and public economizer. The high-temperature heat source and the low-temperature heat source are not separated, and the cascade utilization effect of heat is poor;

[0006] 3. Usually, once the engineering design is completed, the location of the flue gas extraction port and the heating surface of the waste heat boiler have been determined. Affected by the raw materials and fuel of the cement plant, when the actual operating conditions are different from the designed operating conditions, it is difficult for the waste heat recovery system to adjust the heat absorption of the waste heat boiler according to the actual operating conditions of the cement plant, and the superheater parameters are difficult to control. The actual steam parameters entering the turbine device deviate from the optimal operating parameters of the turbine design. The turbine deviates from the optimal operating conditions, making the efficiency of the entire waste heat recovery system low;

[0007] 4. Since the temperature of the kiln head flue gas varies widely, generally fluctuating between ±40℃ of the designed furnace temperature, and the low-pressure section heater used to heat the supplementary air is arranged behind the high-pressure section of the boiler, the steam parameters for supplementary steam are difficult to stabilize. This operating condition will lead to frequent withdrawal and input of the supplementary steam system, resulting in cumbersome operation, low actual system efficiency, and greater impact on the safe operation of the steam turbine;

[0008] In summary, the current technology is difficult to meet the requirements of the cement waste heat recovery system for waste heat recovery efficiency and system working stability. Summary of the invention

[0009] The present invention aims to provide an adjustable dual-pressure waste heat recovery system for a cement kiln head, so as to solve the problem that the current technology is difficult to meet the requirements of the cement waste heat recovery system on waste heat recovery efficiency and system working stability.

[0010] The embodiment of the present invention is achieved as follows:

[0011] An adjustable dual-pressure waste heat recovery system for a cement kiln head, comprising a grate cooler, a high-temperature dust collector, a medium-temperature dust collector, a dual-pressure AQC boiler, a dust collector, an induced draft fan, and a chimney;

[0012] The front section of the grate cooler is provided with a high-temperature air intake, which is connected to the high-temperature dust collector through a pipeline; a high-temperature regulating valve is provided on the pipeline to control the amount of flue gas entering the high-temperature dust collector;

[0013] A medium-temperature air intake is provided in the middle section of the grate cooler, and the medium-temperature air intake is connected to the medium-temperature dust collector through a pipeline; a first medium-temperature regulating valve and a second medium-temperature regulating valve are arranged in series on the pipeline to control the amount of flue gas entering the medium-temperature dust collector;

[0014] A bypass channel is provided on the pipeline after the high-temperature regulating valve and the intermediate pipeline between the first medium-temperature regulating valve and the second medium-temperature regulating valve, and a first bypass regulating valve is provided on the bypass channel to adjust and control the amount of flue gas entering the high-temperature pipeline and the medium-temperature pipeline;

[0015] A low-temperature air intake is provided at the tail of the grate cooler, which is connected to the dust collector inlet through a low-temperature regulating valve, and the dust collector outlet is connected to the chimney through an induced draft fan;

[0016] A second bypass regulating valve is arranged on the intermediate pipeline between the first medium-temperature regulating valve and the second medium-temperature regulating valve and the pipeline in front of the low-temperature regulating valve to regulate and control the amount of flue gas entering the medium-temperature pipeline and the dust collector;

[0017] The dual-pressure AQC boiler is provided with a high-temperature air inlet and a medium-temperature air inlet; a partition is provided in the dual-pressure AQC boiler, and the partition divides the flue gas channel into a high-temperature flue connected to the high-temperature air inlet and a medium-temperature flue connected to the medium-temperature air inlet on the flue gas inlet side of the dual-pressure AQC boiler; the high-temperature air inlet is connected to the high-temperature dust collector through a pipeline, and the medium-temperature air inlet is connected to the medium-temperature dust collector through a pipeline;

[0018] The high-temperature flue gas purified by the high-temperature dust collector enters the high-temperature flue, and the medium-temperature flue gas purified by the medium-temperature dust collector enters the medium-temperature flue;

[0019] A high-pressure section superheater and a high-pressure section evaporator are sequentially arranged in the high-temperature flue of the dual-pressure AQC boiler along the direction of flue gas flow, and a low-pressure section superheater and a low-pressure section evaporator are sequentially arranged in the medium-temperature flue of the dual-pressure AQC boiler from the air inlet end to the air outlet end; the dual-pressure AQC boiler merges into a combined flue after its high-temperature flue and medium-temperature flue; the combined flue is sequentially arranged with a high-pressure section economizer and a common economizer along the direction of flue gas flow;

[0020] The high-pressure section superheater and the high-pressure section evaporator are interconnected to form a high-pressure system, and the low-pressure section superheater and the low-pressure section evaporator are interconnected to form a low-pressure system; the high-pressure system is connected to the high-pressure section economizer and the public economizer in sequence, and the low-pressure system is connected to the public economizer; after the external feed water absorbs heat through the public economizer, one way passes through the water regulating valve directly into the low-pressure system, one way passes through the feed water regulating valve to enter the high-pressure economizer and then absorbs heat and enters the high-pressure system, and the other way goes to the SP boiler system;

[0021] The flue gas outlet of the dual-pressure AQC boiler is connected to the dust collector inlet through a pipeline, and a flue valve is arranged on the pipeline.

[0022] Through the above structural setting, the cement kiln head adjustable dual-pressure waste heat recovery system in the embodiment of the present invention has the following beneficial effects:

[0023] 1. Improved the problem that the AQC boiler of the dual-pressure thermal system has many heating surfaces and is arranged in sequence, which increases the boiler height and the boiler flue gas resistance. The flue is divided into a high-temperature flue and a medium-temperature flue, and the high-pressure section heating surface and the low-pressure section heating surface are arranged in parallel, which reduces the overall height of the boiler and reduces the boiler flue gas resistance;

[0024] 2. Considering the problem that the flue gas volume in the high-temperature section of the grate cooler is relatively small, while the flue gas volume in the low-temperature section is relatively large, two air inlets are set for the dual-pressure AQC boiler. A high-pressure section superheater and a high-pressure section evaporator are set in sequence in the high-temperature flue of the dual-pressure AQC boiler, and a low-pressure section superheater and a low-pressure section evaporator are set in sequence in the medium-temperature flue. After passing through the high-temperature flue and the medium-temperature flue, they are merged into one flue in the boiler. A high-pressure section economizer and a common economizer are set in sequence along the flue gas flow direction, and the high-temperature heat source and the low-temperature heat source are separated. The high-temperature flue gas is used to heat the high-temperature section with higher heating parameters, and the low-temperature flue gas is used to heat the low-temperature section with lower heating parameters, thus realizing the cascade utilization of heat;

[0025] 3. When the actual operation is different from the design working condition, the flue gas volume can be regulated and controlled by controlling the opening of different regulating valves. The waste heat recovery system adjusts the heat absorption of the waste heat boiler according to the actual operation of the cement plant, and adjusts the superheated steam parameters to make the actual steam parameters entering the steam turbine device close to the optimal working condition parameters designed for the steam turbine, so that the steam turbine can operate near the optimal working condition, and the efficiency of the entire waste heat recovery system can be guaranteed;

[0026] 4. When the temperature variation range of the kiln head flue gas is large, the flue gas volume can be regulated by controlling the opening of different regulating valves, so that the steam parameters for steam supplementation are relatively stable. This avoids the frequent withdrawal and input of the steam supplementation system and reduces the impact on the safe operation of the steam turbine;

[0027] In one embodiment:

[0028] The dual-pressure AQC boiler is arranged vertically, with flue gas entering from the upper end and exiting from the lower end; the high-temperature dust collector and the medium-temperature dust collector are both cyclone dust collectors independently arranged outside the dual-pressure AQC boiler.

[0029] In one embodiment:

[0030] The dual-pressure AQC boiler is arranged vertically, with flue gas entering from the lower end and exiting from the upper end;

[0031] The high-temperature flue and the medium-temperature flue of the dual-pressure AQC boiler are respectively extended laterally and bent into an upward U-shaped hook shape, so that the high-temperature air inlet and the medium-temperature air inlet are respectively facing upward; and the high-temperature dust collector and the medium-temperature dust collector are sedimentation-type dust removal structures correspondingly arranged on the inner side of the U-shaped hook part.

[0032] In one embodiment:

[0033] The dual-pressure AQC boiler is arranged horizontally.

[0034] In one embodiment:

[0035] The air volume extracted by the high-temperature air intake port accounts for 30%-70% of the total extracted air volume.

[0036] In one embodiment:

[0037] The air volume extracted by the medium-temperature air intake accounts for 70%-30% of the total air volume extracted.

[0038] In one embodiment:

[0039] The first bypass regulating valve regulates the air volume to account for 0-15% of the total extracted air volume.

[0040] In one embodiment:

[0041] The second bypass regulating valve regulates the air volume to account for 0-15% of the total extracted air volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings mentioned in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 The structural schematic diagram of an implementation mode of an adjustable dual-pressure waste heat recovery system at a cement kiln head in an embodiment of the present invention (arrows are used in the figure to indicate the flow direction of flue gas or water supply);

[0044] Figure 2 It is a structural schematic diagram of another implementation of the adjustable dual-pressure waste heat recovery system at the cement kiln head in an embodiment of the present invention (the arrows in the figure indicate the flow direction of the flue gas or water supply).

[0045] Icons: grate cooler 1, high-temperature dust collector 2, medium-temperature dust collector 3, dual-pressure AQC boiler 4, dust collector 5, induced draft fan 6, chimney 7, high-temperature regulating valve 8, first medium-temperature regulating valve 9, second medium-temperature regulating valve 10, low-temperature regulating valve 11, first bypass regulating valve 12, second bypass regulating valve 13, flue valve 14, high-temperature air intake 15, medium-temperature air intake 16, low-temperature air intake 17, bypass channel 18, partition 19, high-temperature air inlet 20, medium-temperature air inlet 21, water regulating valve 22, high-temperature flue 23, medium-temperature flue 24, combined flue 25, low-pressure section superheater 26, low-pressure section evaporator 27, high-pressure section superheater 28, high-pressure section evaporator 29, high-pressure section economizer 30, common economizer 31. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0047] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Example

[0049] See also Figure 1 This embodiment proposes an adjustable dual-pressure waste heat recovery system for a cement kiln head, which includes a grate cooler 1, a high-temperature dust collector 2, a medium-temperature dust collector 3, a dual-pressure AQC boiler 4, a dust collector 5, an induced draft fan 6 and a chimney 7.

[0050] A high-temperature air intake 15 is provided at the front section of the grate cooler 1, and the high-temperature air intake 15 is connected to the high-temperature dust collector 2 through a pipeline; a high-temperature regulating valve 8 is provided on the pipeline to control the amount of flue gas entering the high-temperature dust collector 5;

[0051] A medium-temperature air intake 16 is provided in the middle section of the grate cooler 1, and the medium-temperature air intake 16 is connected to the medium-temperature dust collector 3 through a pipeline; a first medium-temperature regulating valve 9 and a second medium-temperature regulating valve 10 are arranged in series on the pipeline to control the amount of flue gas entering the medium-temperature dust collector 3;

[0052] A bypass channel 18 is provided on the pipeline after the high-temperature regulating valve 8 and the pipeline between the first medium-temperature regulating valve 9 and the second medium-temperature regulating valve 10, and a first bypass regulating valve 12 is provided on the bypass channel 18 to adjust and control the amount of flue gas entering the high-temperature pipeline and the medium-temperature pipeline; and the flue gas temperature can be adjusted by controlling the amount of flue gas in the two routes;

[0053] A low-temperature air intake 17 is provided at the tail of the grate cooler 1. The low-temperature air intake 17 is connected to the inlet of the dust collector 5 through a low-temperature regulating valve 11. The outlet of the dust collector 5 is connected to the chimney 7 through an induced draft fan 6.

[0054] A second bypass regulating valve 13 is provided on the intermediate pipeline between the first medium temperature regulating valve 9 and the second medium temperature regulating valve 10 and the pipeline before the low temperature regulating valve 11 to regulate and control the amount of flue gas entering the medium temperature pipeline and the dust collector 5;

[0055] The dual-pressure AQC boiler 4 is provided with a high-temperature air inlet 20 and a medium-temperature air inlet 21; a partition 19 is provided inside the dual-pressure AQC boiler 4, and the partition 19 divides the flue gas channel into a high-temperature flue 23 connected to the high-temperature air inlet 20 and a medium-temperature flue 24 connected to the medium-temperature air inlet 21 on the flue gas inlet side of the dual-pressure AQC boiler 4; the high-temperature air inlet 20 is connected to the high-temperature dust collector 2 through a pipeline, and the medium-temperature air inlet 21 is connected to the medium-temperature dust collector through a pipeline; wherein, the dual-pressure AQC boiler 4 adopts a vertical arrangement, and the flue gas enters from the upper end and exits from the lower end; the high-temperature dust collector 2 and the medium-temperature dust collector 3 are both cyclone dust collectors independently arranged outside the dual-pressure AQC boiler 4.

[0056] The high-temperature flue gas purified by the high-temperature dust collector 2 enters the high-temperature flue 23, and the medium-temperature flue gas purified by the medium-temperature dust collector enters the medium-temperature flue 24;

[0057] A high-pressure section superheater 28 and a high-pressure section evaporator 29 are sequentially arranged in the high-temperature flue 23 of the dual-pressure AQC boiler 4 along the direction of flue gas flow, and a low-pressure section superheater 26 and a low-pressure section evaporator 27 are sequentially arranged in the medium-temperature flue 24 of the dual-pressure AQC boiler 4 from the air inlet end to the air outlet end; the dual-pressure AQC boiler 4 merges into a combined flue 25 after its high-temperature flue 23 and the medium-temperature flue 24; the combined flue 25 is sequentially arranged with a high-pressure section economizer 30 and a common economizer 31 along the direction of flue gas flow;

[0058] The high-pressure section superheater 28 and the high-pressure section evaporator 29 are interconnected to form a high-pressure system, and the low-pressure section superheater 26 and the low-pressure section evaporator 27 are interconnected to form a low-pressure system; the high-pressure system is sequentially connected to the high-pressure section economizer 30 and the public economizer 31, and the low-pressure system is connected to the public economizer 31; after the external feed water absorbs heat through the public economizer 31, one way passes through the water regulating valve 22 to directly enter the low-pressure system, one way passes through the feed water regulating valve 22 to enter the high-pressure economizer to absorb heat and then enter the high-pressure system, and the other way goes to the SP boiler system;

[0059] The flue gas outlet of the dual-pressure AQC boiler 4 is connected to the inlet of the dust collector 5 through a pipeline, and a flue valve 14 is arranged on the pipeline.

[0060] Through the above structural setting, the cement kiln head adjustable dual-pressure waste heat recovery system in the embodiment of the present invention has the following beneficial effects:

[0061] 1. Improved the problem that the AQC boiler of the dual-pressure thermal system has many heating surfaces and is arranged in sequence, which increases the boiler height and the boiler flue gas resistance. The flue is divided into a high-temperature flue 23 and a medium-temperature flue 24, and the high-pressure section heating surface and the low-pressure section heating surface are arranged in parallel, which reduces the overall height of the boiler and reduces the boiler flue gas resistance;

[0062] 2. In view of the problem that the flue gas volume in the high-temperature section of the grate cooler 1 is relatively small, and the flue gas volume in the low-temperature section is relatively large, two air inlets are set in the dual-pressure AQC boiler 4, and a high-pressure section superheater 28 and a high-pressure section evaporator 29 are sequentially set in the high-temperature flue 23 of the dual-pressure AQC boiler 4, and a low-pressure section superheater 26 and a low-pressure section evaporator 27 are sequentially set in the medium-temperature flue 24. After passing through the high-temperature flue 23 and the medium-temperature flue, they are merged into one flue in the boiler. A high-pressure section economizer 30 and a common economizer 31 are sequentially set along the flue gas flow direction, and the high-temperature heat source and the low-temperature heat source are separated. The high-temperature flue gas is used to heat the high-temperature section with higher heating parameters, and the low-temperature flue gas is used to heat the low-temperature section with lower heating parameters, thereby realizing the step-by-step utilization of heat;

[0063] 3. When the actual operation is different from the design working condition, the flue gas volume can be regulated and controlled by controlling the opening of different regulating valves. The waste heat recovery system adjusts the heat absorption of the waste heat boiler according to the actual operation of the cement plant, and adjusts the superheated steam parameters to make the actual steam parameters entering the steam turbine device close to the optimal working condition parameters designed for the steam turbine, so that the steam turbine can operate near the optimal working condition, and the efficiency of the entire waste heat recovery system can be guaranteed;

[0064] 4. When the temperature variation range of the kiln head flue gas is large, the flue gas volume can be regulated by controlling the opening of different regulating valves, so that the steam parameters for steam supplementation are relatively stable. This avoids the frequent withdrawal and input of the steam supplementation system and reduces the impact on the safe operation of the steam turbine;

[0065] In this embodiment, optionally, the air volume extracted by the high temperature air intake 15 accounts for 30%-70% of the total air volume, and the air volume extracted by the medium temperature air intake 16 accounts for 70%-30% of the total air volume. The air volume adjusted by the first bypass regulating valve 12 accounts for 0-15% of the total air volume. The air volume adjusted by the second bypass regulating valve 13 accounts for 0-15% of the total air volume.

[0066] See also Figure 2 In another embodiment, the dual-pressure AQC boiler 4 is arranged vertically, with flue gas entering from the lower end and exiting from the upper end; the high-temperature flue 23 and the medium-temperature flue 24 of the dual-pressure AQC boiler 4 are respectively extended and bent laterally to form an upward U-shaped hook, so that the high-temperature air inlet 20 and the medium-temperature air inlet 21 are respectively facing upward; and the high-temperature dust collector 2 and the medium-temperature dust collector 3 are sedimentation-type dust removal structures correspondingly arranged on the inner side of the U-shaped hook part.

[0067] Of course, in other implementations, the dual-pressure AQC boiler 4 may be arranged horizontally as required.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An adjustable dual-pressure waste heat recovery system for a cement kiln head, characterized by: Including grate cooler, high temperature dust collector, medium temperature dust collector, double pressure AQC boiler, dust collector, induced draft fan, chimney; The front section of the grate cooler is provided with a high-temperature air intake, which is connected to the high-temperature dust collector through a pipeline; a high-temperature regulating valve is provided on the pipeline to control the amount of flue gas entering the high-temperature dust collector; A medium-temperature air intake is provided in the middle section of the grate cooler, and the medium-temperature air intake is connected to the medium-temperature dust collector through a pipeline; a first medium-temperature regulating valve and a second medium-temperature regulating valve are arranged in series on the pipeline to control the amount of flue gas entering the medium-temperature dust collector; A bypass channel is provided on the pipeline after the high-temperature regulating valve and the intermediate pipeline between the first medium-temperature regulating valve and the second medium-temperature regulating valve, and a first bypass regulating valve is provided on the bypass channel to adjust and control the amount of flue gas entering the high-temperature pipeline and the medium-temperature pipeline; A low-temperature air intake is provided at the tail of the grate cooler, which is connected to the dust collector inlet through a low-temperature regulating valve, and the dust collector outlet is connected to the chimney through an induced draft fan; A second bypass regulating valve is arranged on the intermediate pipeline between the first medium-temperature regulating valve and the second medium-temperature regulating valve and the pipeline in front of the low-temperature regulating valve to regulate and control the amount of flue gas entering the medium-temperature pipeline and the dust collector; The dual-pressure AQC boiler is provided with a high-temperature air inlet and a medium-temperature air inlet; a partition is provided in the dual-pressure AQC boiler, and the partition divides the flue gas channel into a high-temperature flue connected to the high-temperature air inlet and a medium-temperature flue connected to the medium-temperature air inlet on the flue gas inlet side of the dual-pressure AQC boiler; the high-temperature air inlet is connected to the high-temperature dust collector through a pipeline, and the medium-temperature air inlet is connected to the medium-temperature dust collector through a pipeline; The high-temperature flue gas purified by the high-temperature dust collector enters the high-temperature flue, and the medium-temperature flue gas purified by the medium-temperature dust collector enters the medium-temperature flue; A high-pressure section superheater and a high-pressure section evaporator are sequentially arranged in the high-temperature flue of the dual-pressure AQC boiler along the direction of flue gas flow, and a low-pressure section superheater and a low-pressure section evaporator are sequentially arranged in the medium-temperature flue of the dual-pressure AQC boiler from the air inlet end to the air outlet end; the dual-pressure AQC boiler merges into a combined flue after its high-temperature flue and medium-temperature flue; the combined flue is sequentially arranged with a high-pressure section economizer and a common economizer along the direction of flue gas flow; The high-pressure section superheater and the high-pressure section evaporator are interconnected to form a high-pressure system, and the low-pressure section superheater and the low-pressure section evaporator are interconnected to form a low-pressure system; the high-pressure system is connected to the high-pressure section economizer and the public economizer in sequence, and the low-pressure system is connected to the public economizer; after the external feed water absorbs heat through the public economizer, one way passes through the water regulating valve to directly enter the low-pressure system, one way passes through the feed water regulating valve to enter the high-pressure economizer to absorb heat and then enter the high-pressure system, and the other way goes to the SP boiler system; The flue gas outlet of the dual-pressure AQC boiler is connected to the dust collector inlet through a pipeline, and a flue valve is arranged on the pipeline.

2. The cement kiln head adjustable dual-pressure waste heat recovery system according to claim 1 is characterized in that: The dual-pressure AQC boiler is arranged vertically, with flue gas entering from the upper end and exiting from the lower end; the high-temperature dust collector and the medium-temperature dust collector are both cyclone dust collectors independently arranged outside the dual-pressure AQC boiler.

3. The cement kiln head adjustable dual-pressure waste heat recovery system according to claim 1 is characterized by: The dual-pressure AQC boiler is arranged vertically, with flue gas entering from the lower end and exiting from the upper end; The high-temperature flue and the medium-temperature flue of the dual-pressure AQC boiler are respectively extended laterally and bent into an upward U-shaped hook shape, so that the high-temperature air inlet and the medium-temperature air inlet are respectively facing upward; and the high-temperature dust collector and the medium-temperature dust collector are sedimentation-type dust removal structures correspondingly arranged on the inner side of the U-shaped hook part.

4. The cement kiln head adjustable dual-pressure waste heat recovery system according to claim 1 is characterized by: The dual-pressure AQC boiler is arranged horizontally.

5. The cement kiln head adjustable dual-pressure waste heat recovery system according to any one of claims 1 to 4, characterized in that: The air volume extracted by the high-temperature air intake port accounts for 30%-70% of the total extracted air volume.

6. The cement kiln head adjustable dual-pressure waste heat recovery system according to claim 1 is characterized by: The air volume extracted by the medium-temperature air intake accounts for 70%-30% of the total air volume extracted.

7. The cement kiln head adjustable dual-pressure waste heat recovery system according to claim 1 is characterized by: The first bypass regulating valve regulates the air volume to account for 0-15% of the total extracted air volume.

8. The cement kiln head adjustable dual-pressure waste heat recovery system according to claim 1 is characterized by: The second bypass regulating valve regulates the air volume to account for 0-15% of the total extracted air volume.

Images