Composite bypass ventilation system for gradient utilization of waste heat

Abstract

The utility model discloses a composite bypass ventilation system for gradient utilization of waste heat, which comprises a preheater system provided with a kiln tail smoke chamber and a kiln head grate cooler. The composite bypass ventilation system sequentially comprises a cyclone separator, a waste heat boiler, a dust collector, a salt washing branch and a smoke branch, wherein the salt washing branch and the smoke branch are connected to the dust collector in parallel. The three-stage separation steps of cyclone separator solid-gas separation, preheater solid-gas separation and dust collector solid-gas separation are formed, harmful elements in a cement kiln system are reduced, and the crusting and blocking risks of the preheater are relieved. In addition, co-treatment of the flue gas and the waste gas of the environment-friendly workshop is realized at the cyclone separator; at the waste heat boiler, a part of steam is generated and supplied to a salt water evaporation system for salt production; flue gas with fine ash separated through the dust collector is conveyed into the salt washing branch at the dust collector to jointly form a three-stage waste heat utilization step, and the operation cost of cement enterprises is saved.

Description

Technical Field

[0001] This utility model relates to the field of co-processing alternative fuels in cement kilns, specifically to a composite bypass venting system for the cascade utilization of waste heat. Background Technology

[0002] The process of cement companies utilizing carbon market mechanisms to achieve green and low-carbon transformation is now accelerating. Among these efforts, co-processing to replace raw materials and fuels has become one of the core technological means for cement companies to achieve their emission reduction targets, offering the dual advantages of waste resource utilization and improved environmental benefits.

[0003] In the process of co-processing alternative fuels, enterprises need to collect and treat exhaust gases from environmentally friendly workshops storing alternative fuels. Simultaneously, the combustion of large quantities of alternative fuels introduces significant amounts of volatile harmful components such as sulfur, chlorine, and alkali, which circulate and accumulate in the cement kiln system, causing process problems such as scaling and blockage in the preheater system. To address this issue, the industry generally adopts bypass venting systems. However, existing bypass venting systems mostly employ different refrigerant quenching processes to rapidly cool high-temperature flue gas, but generally neglect the recovery and utilization of the abundant waste heat resources contained in the flue gas, resulting in significant thermal energy waste, which contradicts the cement industry's pursuit of low-carbon and energy-saving development goals. Under the overarching goal of "dual carbon" (carbon reduction and energy conservation), how to solve the series of problems brought about by alternative fuels while fully exploring and utilizing waste heat resources has become a crucial issue that cement enterprises urgently need to address. Utility Model Content

[0004] To address the aforementioned shortcomings of existing technologies, a composite bypass venting system for the cascade utilization of waste heat is provided. This system reduces harmful elements within the cement kiln system, alleviates the risk of scale formation and blockage in the preheater, achieves the synergistic treatment of waste gas from the environmental protection workshop, improves the efficiency of water washing and salt extraction, completes the efficient cascade utilization of waste heat from bypass venting, and saves operating costs for cement enterprises.

[0005] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows:

[0006] The composite bypass ventilation system for waste heat cascade utilization includes a preheater system with a kiln tail flue chamber and a kiln head grate cooler. Along the bypass high-temperature flue gas treatment path, the composite bypass ventilation system sequentially includes a cyclone separator, a dust collector, and a water washing salt branch and a flue gas branch connected in parallel to the dust collector. The kiln tail flue chamber is connected to the cyclone separator via a hot air duct. A waste gas collection system connected to the environmental protection workshop is also connected to the hot air duct between the kiln tail flue chamber and the cyclone separator. A salt drying device is installed at the end of the water washing salt branch. The end of the flue gas branch, the salt drying device, the kiln head grate cooler, and the preheater system are sequentially connected via pipelines. The flue gas enters the preheater system from the end of the flue gas branch. The preheater system is also connected to an external kiln tail waste gas treatment system. The cyclone separator is also connected to the preheater system via a coarse ash conveying device.

[0007] According to the above technical solution, it also includes a waste heat boiler, which is connected between the cyclone separator and the dust collector, and the bottom of the waste heat boiler is also connected to the water washing salt branch.

[0008] According to the above technical solution, a direct connection pipe is also provided between the cyclone separator and the dust collector; when the waste heat boiler is not in use, the cyclone separator and the dust collector are directly connected.

[0009] According to the above technical solution, the water washing salt branch includes a fine ash conveying device, a water washing system, an evaporation system, and a salt drying device connected in sequence; the waste heat boiler and the dust collector are both connected to the fine ash conveying device; the waste heat boiler is also connected to the evaporation system or to an external cement kiln waste heat power generation system.

[0010] According to the above technical solution, a mixing chamber is also provided between the end of the flue gas branch and the kiln head grate cooler. The mixing chamber and the salt drying device are connected in parallel between the flue gas branch and the kiln head grate cooler. The waste gas collection system connected to the environmental protection workshop is connected to the mixing chamber. Depending on the needs, the end of the flue gas branch is connected to the mixing chamber or to the salt drying device.

[0011] According to the above technical solution, a bypass system fan is provided on the flue gas branch.

[0012] According to the above technical solution, a high-temperature gate valve is also installed on the pipeline between the kiln tail smoke chamber and the cyclone separator.

[0013] According to the above technical solutions, the dust collectors include bag dust collectors, sintered plastic plate dust collectors, electrostatic precipitators, ceramic tube dust collectors, and electrostatic-bag composite dust collectors.

[0014] According to the above technical solution, at least two temperature sensors should be installed at the outlet of the cyclone separator, and the temperature sensors should be installed on at least both sides of the outlet.

[0015] This utility model has the following beneficial effects:

[0016] 1. This system transports the flue gas from the kiln tail chamber to a cyclone separator, where it undergoes two solid-liquid separation processes using both the cyclone separator and a dust collector. The coarse ash separated by the cyclone separator is transported to the preheater system, while the fine ash separated by the dust collector is transported to the washing salt branch for salt production. This reduces harmful elements within the cement kiln system and mitigates the risk of scaling and clogging in the preheater. Secondly, it transports waste gas from the environmental protection workshop to the cyclone separator, achieving co-treatment of this waste gas. Furthermore, it transports the flue gas, after fine ash separation by the dust collector, to the washing salt branch, improving the efficiency of salt extraction. These two processes together achieve efficient cascade utilization of waste heat from bypass venting, saving operating costs for cement companies.

[0017] 2. The addition of a waste heat boiler creates a three-stage separation process: solid-gas separation in the cyclone separator, solid-gas separation in the preheater, and solid-gas separation in the dust collector. This reduces harmful elements in the cement kiln system and alleviates the risk of scale buildup and blockage in the preheater. Furthermore, the cyclone separator enables the co-treatment of flue gas and waste gas from the environmental protection workshop; the waste heat boiler generates steam to supply the brine evaporation system for salt production; and the dust collector transports the flue gas, after separating fine ash, to the washing salt branch line, forming a three-stage waste heat utilization system that further reduces the operating costs of cement enterprises.

[0018] 3. Add a mixing chamber to complete the secondary co-treatment of waste gas in the environmental protection workshop when the preparation of washing salt is not required. This replaces the "transporting the flue gas that has been separated into fine ash by the dust collector to the washing salt branch", forming a three-stage waste heat utilization ladder and saving the operating costs of cement enterprises.

[0019] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it according to the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. The specific implementation methods of this utility model are given in detail in the following embodiments and their accompanying drawings. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the present invention and form part of this application, illustrate exemplary embodiments of the present invention and are used to explain the present invention, but do not constitute an undue limitation of the present invention.

[0021] Figure 1 This is a schematic diagram of Embodiment 1 of the present invention (including a mixing chamber);

[0022] Figure 2 This is a schematic diagram of Embodiment 2 of the present invention (including a mixing chamber);

[0023] Figure 3This is a schematic diagram of Embodiment 3 of the present invention (including a mixing chamber);

[0024] In the diagram, 1. Kiln tail flue; 2. Kiln head grate cooler; 3. Cyclone separator; 4. Dust collector; 5. Salt washing branch; 5-1. Salt drying device; 5-2. Fine ash conveying device; 5-3. Washing system; 5-4. Evaporation system; 6. Flue gas branch; 6-1. Bypass system fan; 7. Environmental protection workshop; 8. Waste gas collection system; 9. Coarse ash conveying device; 10. High-temperature gate valve; 11. Waste heat boiler; 12. Mixing chamber; 13. Kiln tail waste gas treatment system; 14. Preheater system. Detailed Implementation

[0025] The following is in conjunction with the appendix Figures 1-3 The principles and features of this utility model are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of this utility model. The utility model is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of this utility model will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this utility model.

[0026] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] Reference Figures 1-3 As shown, this utility model provides a composite bypass ventilation system for the cascade utilization of waste heat. This system is mainly suitable for the later-stage renovation of cement plants that use alternative fuels and are equipped with water washing and salt extraction systems.

[0029] Example 1

[0030] like Figure 1As shown, the system includes a preheater system 14 with a kiln tail flue chamber 1 and a kiln head grate cooler 2. Along the bypass high-temperature flue gas treatment path, the composite bypass ventilation system sequentially includes a cyclone separator 3, a dust collector 4, and a water-washed salt branch 5 and a flue gas branch 6 connected in parallel to the dust collector. The kiln tail flue chamber is connected to the cyclone separator via a hot air duct. A waste gas collection system 8 connected to the environmental protection workshop 7 is also connected to the hot air duct between the kiln tail flue chamber and the cyclone separator. A salt drying device 5-1 is provided at the end of the water-washed salt branch. The end of the flue gas branch, the salt drying device, the kiln head grate cooler, and the preheater system are sequentially connected via pipes. The flue gas enters the preheater system from the end of the flue gas branch. The preheater system is also connected to the external kiln tail waste gas treatment system. The cyclone separator is also connected to the kiln tail flue chamber via a coarse ash conveying device 9.

[0031] The salt washing branch includes a fine ash conveying device 5-2, a washing system 5-3, an evaporation system 5-4, and a salt drying device 5-5 connected in sequence; the dust collector is connected to the fine ash conveying device.

[0032] The flue gas branch is equipped with a bypass system fan 6-1.

[0033] A high-temperature gate valve 10 is also installed on the pipeline between the kiln tail smoke chamber and the cyclone separator.

[0034] At least two temperature sensors are installed at the outlet of the cyclone separator, and the temperature sensors are installed on at least both sides of the outlet.

[0035] Preferably, the dust collector is a bag dust collector, a sintered plastic plate dust collector, an electrostatic precipitator, a ceramic tube dust collector, or an electrostatic-bag composite dust collector.

[0036] In Example 1, the kiln tail flue is connected to the cyclone separator via a hot air duct. An air inlet for the environmental protection workshop exhaust gas collection system is provided on the hot air duct at the inlet of the cyclone separator. The flue gas entering from the kiln tail flue and the exhaust gas entering from the exhaust gas collection system are fully mixed and undergo rapid heat exchange in the hot air duct before entering the cyclone separator together for dust particle size separation.

[0037] Coarse particles in the mixed gas fall to the bottom of the cyclone separator and are then fed into the preheater system via a coarse ash conveying device. After rapid cooling and particle size separation, the flue gas enters a bag filter for gas-solid separation. The bypass ash in the bag filter hopper is sent to the washing system for further processing via a fine ash conveying device. After processing, the brine enters the evaporation system for salt production. The flue gas after gas-solid separation in the bag filter is discharged through the bypass system fan and introduced into the finished salt drying system. The flue gas then enters the high-temperature section of the kiln head grate cooler for incineration in the kiln, and is further treated by the cement kiln denitrification and desulfurization system. After passing through the kiln tail exhaust gas treatment system 13, it is finally discharged through the kiln tail chimney after meeting emission standards.

[0038] Example 2

[0039] like Figure 2 As shown, the system includes a preheater system with a kiln tail flue gas chamber and a kiln head grate cooler. Along the bypass high-temperature flue gas treatment path, the composite bypass ventilation system sequentially includes a cyclone separator, a dust collector, and a water-washed salt branch and a flue gas branch connected in parallel to the dust collector. The kiln tail flue gas chamber is connected to the cyclone separator via a hot air duct. A waste gas collection system connected to an environmental protection workshop is also connected to the hot air duct between the kiln tail flue gas chamber and the cyclone separator. A salt drying device is installed at the end of the water-washed salt branch. The end of the flue gas branch, the salt drying device, the kiln head grate cooler, and the preheater system are sequentially connected via pipes. Flue gas enters the preheater system from the end of the flue gas branch. The preheater system is also connected to an external kiln tail waste gas treatment system. The cyclone separator is also connected to the preheater system via a coarse ash conveying device.

[0040] It also includes a waste heat boiler 11, which is connected between the cyclone separator and the dust collector, and the bottom of the waste heat boiler is also connected to the water washing salt branch.

[0041] The salt washing branch includes a fine ash conveying device, a washing system, an evaporation system, and a salt drying device connected in sequence; the waste heat boiler and the dust collector are both connected to the fine ash conveying device; the waste heat boiler is also connected to the evaporation system or to an external cement kiln waste heat power generation system.

[0042] The flue gas branch is equipped with a bypass system fan.

[0043] A high-temperature gate valve is also installed on the pipeline between the kiln tail smoke chamber and the cyclone separator.

[0044] Preferably, the dust collector is a bag dust collector, a sintered plastic plate dust collector, an electrostatic precipitator, a ceramic tube dust collector, or an electrostatic-bag composite dust collector.

[0045] At least two temperature sensors are installed at the outlet of the cyclone separator, and the temperature sensors are installed on at least both sides of the outlet.

[0046] In Example 2, the kiln tail flue is connected to the cyclone separator via a hot air duct. An air inlet for the environmental protection workshop exhaust gas collection system is provided on the hot air duct at the inlet of the cyclone separator. The flue gas entering from the kiln tail flue and the exhaust gas entering from the exhaust gas collection system are fully mixed and undergo rapid heat exchange in the hot air duct before entering the cyclone separator together for dust particle size separation.

[0047] Coarse particles in the mixed gas fall to the bottom of the cyclone separator and are then fed into the preheater system via a coarse ash conveying device. After rapid cooling and particle size separation, the flue gas enters the waste heat boiler. A portion of the steam generated by the waste heat boiler can supply the brine evaporation system (or be connected to the cement kiln waste heat power generation system). Simultaneously, the flue gas undergoes further particle size separation in the waste heat boiler through gravity settling. After the first waste heat utilization, the flue gas is introduced into a bag filter for further gas-solid separation via pipeline. The bypass ash from the waste heat boiler and the bypass ash from the bag filter hopper are sent to the washing system for further processing via a fine ash conveying device. After processing, the brine enters the evaporation system for salt production. The flue gas, after three gas-solid separations, is discharged through the bypass system fan and introduced into the finished salt drying system. The flue gas then enters the high-temperature section of the kiln head grate cooler for incineration in the kiln, undergoes further treatment through the cement kiln denitrification and desulfurization system, then passes through the kiln tail exhaust gas treatment system, and finally is discharged through the kiln tail chimney after meeting emission standards.

[0048] Example 3

[0049] like Figure 3 As shown, the system includes a preheater system with a kiln tail flue gas chamber and a kiln head grate cooler. Along the bypass high-temperature flue gas treatment path, the composite bypass ventilation system sequentially includes a cyclone separator, a dust collector, and a water-washed salt branch and a flue gas branch connected in parallel to the dust collector. The kiln tail flue gas chamber is connected to the cyclone separator via a hot air duct. A waste gas collection system connected to an environmental protection workshop is also connected to the hot air duct between the kiln tail flue gas chamber and the cyclone separator. A salt drying device is installed at the end of the water-washed salt branch. The end of the flue gas branch, the salt drying device, the kiln head grate cooler, and the preheater system are sequentially connected via pipes. Flue gas enters the preheater system from the end of the flue gas branch. The preheater system is also connected to an external kiln tail waste gas treatment system. The cyclone separator is also connected to the preheater system via a coarse ash conveying device.

[0050] It also includes a waste heat boiler, which is connected between the cyclone separator and the dust collector, and the bottom of the waste heat boiler is also connected to the water washing salt branch. A direct connection pipe is also provided between the cyclone separator and the dust collector; when the waste heat boiler is not in use, the cyclone separator and the dust collector are directly connected.

[0051] The salt washing branch includes a fine ash conveying device, a washing system, an evaporation system, and a salt drying device connected in sequence; the waste heat boiler and the dust collector are both connected to the fine ash conveying device; the waste heat boiler is also connected to the evaporation system or to an external cement kiln waste heat power generation system.

[0052] The flue gas branch is equipped with a bypass system fan.

[0053] A high-temperature gate valve is also installed on the pipeline between the kiln tail smoke chamber and the cyclone separator.

[0054] Preferably, the dust collector is a bag dust collector, a sintered plastic plate dust collector, an electrostatic precipitator, a ceramic tube dust collector, or an electrostatic-bag composite dust collector.

[0055] At least two temperature sensors are installed at the outlet of the cyclone separator, and the temperature sensors are installed on at least both sides of the outlet.

[0056] Example 3 incorporates two flue gas treatment methods, namely, Example 1 and Example 2. Two parallel pathways are established between the cyclone separator and the dust collector; one is directly connected by a pipeline, and the other involves a waste heat boiler installed between the cyclone separator and the dust collector. During waste heat boiler maintenance, flue gas directly enters the dust collector from the cyclone separator; during normal operation of the waste heat boiler, flue gas enters the waste heat boiler from the cyclone separator.

[0057] Example 4

[0058] Based on Examples 1-3, a mixing chamber 12 is also provided between the end of the flue gas branch and the kiln head grate cooler. The mixing chamber and the salt drying device are connected in parallel between the flue gas branch and the kiln head grate cooler. The waste gas collection system connected to the environmental protection workshop is connected to the mixing chamber. Depending on the needs, the end of the flue gas branch is connected to the mixing chamber or to the salt drying device.

[0059] The exhaust gas can be introduced into the finished salt drying system during the salt production period. During non-salt production periods, it can be introduced into the mixing chamber and mixed with the exhaust gas from the waste gas collection system. This utilizes the waste gas from the environmentally friendly workshop to cool the hot flue gas from non-salt production periods, ensuring the flue gas reaches the required temperature for entry into the grate cooler. The mixed flue gas is then transported to the kiln head grate cooler.

[0060] In the above embodiments, the exhaust gas collection system is used as a refrigerant for the exhaust gas from the environmental protection workshop, the cyclone separator is used for rapid cooling of high-temperature flue gas and separation of coarse dust particles, the coarse ash conveying device is used for coarse ash at the bottom of the cyclone separator, the waste heat boiler is used for the first utilization of waste heat, the dust collector is used for the second separation of dust from the flue gas, the fine ash conveying device is used for conveying fine ash at the bottom of the waste heat boiler and the bag dust collector, and the bypass system fan is used to provide operating power for the flue gas branch, the pipeline between the kiln tail flue and the dust collector.

[0061] Taking Example 3 as an example, the principle of this utility model is as follows:

[0062] During operation, first open the valves and conveying devices on each duct, then start the fans and other equipment along the ducts. Under the action of the bypass system fan, a certain amount of high-temperature flue gas (1050~1250℃) flows from the kiln tail flue through the high-temperature duct and mixes rapidly with the waste gas from the environmental protection workshop before entering the cyclone separator. Temperature sensors (no fewer than two, and not all installed on the same side of the outlet) are installed at the cyclone separator outlet. The bypass system fan or the environmental protection workshop waste gas collection system can adjust the airflow based on this temperature signal to rapidly cool the flue gas to below 600℃. The coarse ash conveying device at the bottom of the cyclone separator sends it to the preheater system. After rapid cooling and particle size separation, the flue gas enters the waste heat boiler. A portion of the steam generated by the waste heat boiler can be supplied to the brine evaporation system for salt production (or it can be combined with the cement kiln waste heat power generation system; this is the first waste heat utilization). Simultaneously, particle size separation is completed again through gravity settling. After the first waste heat utilization, the flue gas is introduced into the dust collector through a pipeline for further gas-solid separation. The bypass ash from the waste heat boiler and the bypass ash from the bag filter dust collector are conveyed to the water washing system for further processing. After processing, the brine enters the evaporation system for salt production. The flue gas, after three gas-solid separations, is discharged through the bypass system fan. During the salt production period, the discharged flue gas can be introduced into the finished salt drying system. During non-salt production periods, it can be introduced into the mixing chamber and mixed with the waste gas from the waste gas collection system. The waste gas from the environmental protection workshop is used to cool the hot flue gas during non-salt production to meet the temperature requirements for entering the grate cooler. The mixed flue gas is then conveyed to the kiln head grate cooler. The mixed flue gas enters the high-temperature section of the kiln head grate cooler for incineration in the kiln, and is further treated by the cement kiln denitrification and desulfurization system. After passing through the kiln tail waste gas treatment system, it is finally discharged through the kiln tail chimney after meeting emission standards.

[0063] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any way. Those skilled in the art can readily implement this utility model based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the utility model's technical solution, utilizing the disclosed technical content, are equivalent embodiments of this utility model. Furthermore, any equivalent changes, alterations, or variations made to the above embodiments based on the essential technology of this utility model are still within the protection scope of this utility model's technical solution.

Claims

1. A composite bypass venting system for the cascade utilization of waste heat, comprising a preheater system with a kiln tail smoke chamber and a kiln head grate cooler, characterized in that: Along the bypass high-temperature flue gas treatment path, the composite bypass ventilation system sequentially includes a cyclone separator, a dust collector, and a water washing salt branch and a flue gas branch connected in parallel to the dust collector; the kiln tail flue is connected to the cyclone separator via a hot air duct, and a waste gas collection system connected to the environmental protection workshop is also connected to the hot air duct between the kiln tail flue and the cyclone separator; a salt drying device is provided at the end of the water washing salt branch, and the end of the flue gas branch, the salt drying device, the kiln head grate cooler, and the preheater system are sequentially connected via pipes, and the flue gas enters the preheater system from the end of the flue gas branch, and the preheater system is also connected to the external kiln tail waste gas treatment system; the cyclone separator is also connected to the preheater system via a coarse ash conveying device.

2. The composite bypass ventilation system for waste heat cascade utilization according to claim 1, characterized in that: It also includes a waste heat boiler, which is connected between the cyclone separator and the dust collector, and the bottom of the waste heat boiler is also connected to the water washing salt branch.

3. The composite bypass ventilation system for waste heat cascade utilization according to claim 2, characterized in that: A direct connection pipe is also provided between the cyclone separator and the dust collector; when the waste heat boiler is not in use, the cyclone separator and the dust collector are directly connected.

4. The composite bypass ventilation system for waste heat cascade utilization according to claim 2 or 3, characterized in that: The salt washing branch includes a fine ash conveying device, a washing system, an evaporation system, and a salt drying device connected in sequence; the waste heat boiler and the dust collector are both connected to the fine ash conveying device; the waste heat boiler is also connected to the evaporation system or to an external cement kiln waste heat power generation system.

5. The composite bypass ventilation system for waste heat cascade utilization according to claim 1, characterized in that: A mixing chamber is also provided between the end of the flue gas branch and the kiln head grate cooler. The mixing chamber and the salt drying device are connected in parallel between the flue gas branch and the kiln head grate cooler. The waste gas collection system connected to the environmental protection workshop is connected to the mixing chamber. Depending on the needs, the end of the flue gas branch is connected to the mixing chamber or to the salt drying device.

6. The composite bypass ventilation system for waste heat cascade utilization according to claim 1, characterized in that: A bypass system fan is installed on the flue gas branch.

7. The composite bypass ventilation system for waste heat cascade utilization according to claim 1, characterized in that: A high-temperature gate valve is also installed on the pipeline between the kiln tail smoke chamber and the cyclone separator.

8. The composite bypass ventilation system for waste heat cascade utilization according to claim 1, characterized in that: The dust collector can be a bag filter, a sintered plastic plate dust collector, an electrostatic precipitator, a ceramic tube dust collector, or an electrostatic-bag filter hybrid dust collector.

9. The composite bypass ventilation system for waste heat cascade utilization according to claim 1, characterized in that: At least two temperature sensors should be installed at the outlet of the cyclone separator, and the temperature sensors should be installed on at least both sides of the outlet.

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