Sludge drying and incineration closed-loop circulation system

Abstract

The invention provides a sludge drying and incineration closed-loop circulation system which is formed by a sludge conveying and drying device, an incinerator, a high-temperature heat exchanger, a drying flue gas circulation device and a main fan, and incineration flue gas at the temperature of 850 DEG C discharged by the incinerator enters the high-temperature heat exchanger and rotary sludge drying treatment equipment respectively; one branch of an output port of the drying flue gas circulating device enters a first receiving cavity of the high-temperature heat exchanger and is used for providing heat for external gas treatment equipment through external waste gas treatment equipment connected with the output end of the high-temperature heat exchanger after heat exchange is carried out on part of incineration flue gas and the drying flue gas; and the other branch of the output port of the drying flue gas circulating device is directly mixed with incineration flue gas discharged from the second receiving cavity of the high-temperature heat exchanger and then enters the incinerator to be incinerated and recycled, so that the incineration efficiency is prevented from being influenced when the high-temperature heat exchanger is overloaded and the temperature of the mixed flue gas entering the incinerator is too low.

Description

Technical Field

[0001] The invention relates to the technical field of sludge incineration treatment, and more specifically, to a sludge drying and incineration closed-loop circulation system. Background Art

[0002] Sludge is the solid sediment produced during sewage treatment, mainly containing a large amount of organic debris, bacteria, inorganic particles and colloids, etc. If discharged at will, it will cause pollution to the environment. The sludge treatment method with dry incineration as the core is currently a more reasonable and effective treatment method. The dry incineration treatment method is more conducive to carbonizing organic matter, killing pathogens, reducing sludge volume, and achieving sludge treatment reduction, harmlessness, stabilization and resource utilization.

[0003] Publication number: CN219389759U, a sludge drying and incineration closed-loop circulation device, disclosed includes a sludge conveying device 1, an incineration treatment device 2, a drying circulation device 3, a washing tower 4, and a cooling device 5, characterized in that: the sludge output port of the sludge conveying device 1 is connected to the sludge input port of the incineration treatment device 2, the drying flue gas output port of the sludge conveying device 1 is connected to the drying flue gas input port of the washing tower 4, the drying flue gas output port of the washing tower 4 is connected to the incineration treatment device 2 through the drying circulation device 3, and the liquid outlet of the washing tower 4 is provided with a cooling device 5.

[0004] In the existing patents, the dried flue gas output by the sludge conveying device is processed by a washing tower and a cooling tower, which wastes a large amount of usable flue gas. The circulation path of the closed-loop circulation structure is long and the circulation time is long, which makes it easy for flammable and explosive substances to remain in the pipeline. When the concentration of flammable and explosive substances in the pipeline increases, the explosion hazard of the processing equipment is further increased.

[0005] Therefore, how to solve the low flue gas utilization rate, flue gas waste and explosion in the existing sludge incineration treatment process is an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0006] In view of this, the present invention provides a sludge drying and incineration closed-loop circulation system which has high flue gas utilization rate and is not prone to explosion.

[0007] A sludge drying and incineration closed-loop circulation system, comprising a sludge conveying and drying device 1, an incinerator 2, a high-temperature heat exchanger 3, and a drying flue gas circulation device 4, characterized in that: the combustion flue gas output port of the incinerator 2 is respectively connected to the combustion flue gas input port of the high-temperature heat exchanger 3 and the combustion flue gas input port of the sludge conveying and drying device 1, the drying flue gas output port of the sludge conveying and drying device 1 is connected to the input port of the drying flue gas circulation device 4, and the output port of the drying flue gas circulation device 4 is divided into two branches, and the high-temperature heat exchanger 3 is provided with a first receiving chamber and a second receiving chamber, the first receiving chamber is used to receive the drying flue gas, and the second receiving chamber is used to receive the incineration flue gas, and the drying flue gas circulation device 4 is used to receive the combustion flue gas. The flue gas from the drying process and the incineration process are heat exchanged in the high-temperature heat exchanger 3. One of the branches of the output port of the drying flue gas circulation device 4 enters the first receiving chamber of the high-temperature heat exchanger 3, which is used to exchange heat between part of the incineration flue gas and the drying flue gas and then pass through the external exhaust gas treatment equipment 6 connected to the output end of the high-temperature heat exchanger 3 to provide heat for the external exhaust gas treatment equipment 6. The other branch of the output port of the drying flue gas circulation device 4 is directly mixed with the incineration flue gas discharged from the second receiving chamber of the high-temperature heat exchanger 3 and then enters the incineration cyclic use in the incineration 2 to prevent the high-temperature heat exchanger 3 from being overloaded and the mixed flue gas temperature entering the incinerator 2 being too low, which affects the incineration efficiency.

[0008] Furthermore, an air inlet is provided at the bottom of the incinerator 2 , and a main fan 5 is connected to the air inlet. The main fan 5 is used to provide combustion-supporting oxygen for the incinerator 2 .

[0009] Furthermore, the sludge output port of the sludge conveying and drying device 1 is connected to the sludge input port of the incinerator 2. After the sludge comes into contact with the high-temperature combustion flue gas output by the incinerator 2 in the sludge conveying and drying device 1, it is rotated and dried and then re-output to the incinerator 2 to become a combustion medium.

[0010] Furthermore, the sludge conveying and drying device 1 includes a sludge conveyor 11, a sludge rotary dryer 12, a drying tower 13, and a bag dust collector 14. A high-temperature air inlet channel 121 is provided at one end above the sludge rotary dryer 12. When the temperature at the high-temperature air inlet channel 121 is higher, the rotation efficiency inside the sludge rotary dryer 12 is higher. One end of the incineration flue gas output port of the incinerator 2 is connected to the high-temperature air inlet channel 121. A drying tower 13 is provided at the other end above the sludge rotary dryer 12. The drying tower 13 is used to dry the sludge and discharge the treated sludge and the high-temperature drying flue gas. The external sludge The sludge output device is connected to the sludge input port of the sludge conveyor 11, the sludge output port of the sludge conveyor 11 is connected to the sludge input port of the sludge rotary dryer 12, the sludge output port of the sludge rotary dryer 12 is connected to the sludge input port of the drying tower 13, the sludge output port of the drying tower 13 is connected to the sludge input port of the bag dust collector 14, the bag dust collector 14 is used to receive the sludge and drying flue gas for solid-gas separation and then discharge them separately, the sludge output port of the bag dust collector 14 is connected to the sludge input port of the incinerator 2, and the drying flue gas output port of the bag dust collector 14 is connected to the input port of the drying flue gas circulation device 4.

[0011] Furthermore, an emergency cooling device 122 is provided on the side of the high-temperature air intake passage 121 for emergency cooling of the high-temperature air intake passage 121 in case of a fault.

[0012] Furthermore, a first liquid-cooled feeder 15 is provided between the connecting pipe between the sludge outlet of the bag filter 14 and the sludge inlet of the incinerator 2, for quantitatively outputting the sludge after solid-liquid separation to the incinerator 2 and playing a role of gas sealing.

[0013] Furthermore, the drying flue gas circulation device 4 includes a drying circulation induced draft fan 41, the drying flue gas output port of the bag filter 14 is connected to the drying flue gas input port of the drying circulation induced draft fan 41, and a first regulating valve 16 is provided on the connecting pipe between the drying flue gas output port of the drying circulation induced draft fan 41 and the drying flue gas input port of the first receiving chamber of the high-temperature heat exchanger 3, which is used to control the drying flue gas output amount.

[0014] Furthermore, another branch through which the output port of the drying flue gas circulation device 4 directly mixes with the incineration flue gas discharged from the second receiving chamber of the high-temperature heat exchanger 3 is a first bypass regulating pipe 31. A second regulating valve 32 is provided on the first bypass regulating pipe 31 for assisting in regulating the output of the drying flue gas. When the high-temperature heat exchanger 3 is overloaded, the second regulating valve 32 opens to disperse the gas volume in the first bypass regulating pipe 31, and at the same time enables the temperature of the mixed flue gas entering the incinerator 2 not to be too low.

[0015] Furthermore, the drying flue gas output port of the drying circulation induced draft fan 41 is connected to the drying flue gas input port of the first receiving chamber, the drying flue gas output port of the first receiving chamber is connected to the drying flue gas input port of the incinerator 2, the combustion flue gas output port of the incinerator 2 is connected to the combustion flue gas input port of the second receiving chamber, and the combustion flue gas output port of the first receiving chamber is connected to the input port of the external exhaust gas treatment equipment 6.

[0016] Furthermore, the sludge conveyor 11 and the sludge rotary dryer 12 are both feeders with a spiral structure.

[0017] Beneficial effects of the present invention: The present invention proposes a sludge drying and incineration closed-loop circulation system, comprising a sludge drying feeding device 1, an incinerator 2, a high-temperature heat exchanger 3, a drying flue gas circulation device 4, and a main fan 5. The sludge drying feeding device 1, the incinerator 2, the high-temperature heat exchanger 3, the drying flue gas circulation device 4, and the main fan 5 form a short-stroke, wind speed, and wind pressure closed-loop circulation system. The 850°C incineration flue gas discharged from the incinerator 2 enters the high-temperature heat exchanger 3 and the sludge rotary dryer 12 respectively. The 850°C incineration flue gas is directly dried by high-temperature direct contact with the sludge in the sludge rotary dryer 12 to form flue gas containing harmful gases such as VOC and sulfur dioxide. The harmful flue gas is input into the incinerator 2 for incineration and recycling, thereby solving the problem of difficult treatment of emission gas pollution and effectively utilizing the The drying flue gas reduces the resource waste rate and improves the drying efficiency of the sludge drying feeding device 1. The short stroke also reduces the concentration of flammable and explosive substances contained in the drying flue gas, and the probability of increased retention in the circulation pipeline to increase the safety hazard, thereby improving the safe operation rate. One of the branches of the output port of the drying flue gas circulation device 4 enters the first receiving chamber of the high-temperature heat exchanger 3, which is used to exchange heat between part of the combustion flue gas and the drying flue gas and then pass through the external exhaust gas treatment equipment 6 connected to the output end of the high-temperature heat exchanger 3 to provide heat for the external exhaust gas treatment equipment 6. The other branch of the output port of the drying flue gas circulation device 4 is directly mixed with the combustion flue gas discharged from the second receiving chamber of the high-temperature heat exchanger 3 and then enters the incinerator 2 for incineration and circulation, thereby preventing the high-temperature heat exchanger 3 from being overloaded and the mixed flue gas temperature entering the incinerator 2 being too low, thereby affecting the incineration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the sludge drying and incineration closed-loop circulation system of the present invention.

[0019] Main component symbols

[0020] Sludge conveying device 1 Sludge conveyor 11 Sludge rotary dryer 12 High temperature air intake passage 121 Emergency cooling device 122 Drying tower 13 Bag filter 14 First liquid cooling feeder 15 First regulating valve 16 Incinerator 2 High temperature heat exchanger 3 First bypass regulating pipe 31 Second regulating valve 32 Drying flue gas circulation device 4 Drying circulation induced draft fan 41 Main fan 5 External exhaust gas treatment equipment 6

[0021] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0022] The following examples are described to assist the understanding of the present application, and the examples are not and should not be interpreted in any way as limiting the scope of protection of the present application.

[0023] In the following description, those skilled in the art will recognize that throughout this discussion, components may be described as separate functional units (which may include sub-units), but those skilled in the art will recognize that various components or portions thereof may be divided into separate components or may be integrated together (including within a single system or component).

[0024] At the same time, the connections between components or systems in the drawings are not intended to be limited to direct connections. Instead, the data between these components may be modified, reformatted, or otherwise changed by intermediate components. In addition, additional or fewer connections may be used. It should also be noted that the terms "coupled," "connected," or "input" or "fixed" should be understood to include direct connections, indirect connections or fixations performed through one or more intermediate media.

[0025] In the description of the present application, it should be noted that the terms "center", "up", "down", "left", "right", "side", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships when the product of the application is used or commonly known, and are only for the convenience of describing the present application 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 application. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted. Specific embodiment:

[0027] like Figure 1 The figure shows the structure of the closed-loop sludge drying and incineration system of the present invention.

[0028] A sludge drying and incineration closed-loop circulation system comprises a sludge conveying and drying device 1, an incinerator 2, a high-temperature heat exchanger 3, and a drying flue gas circulation device 4. The incineration flue gas output port of the incinerator 2 is respectively connected to the incineration flue gas input port of the high-temperature heat exchanger 3 and the incineration flue gas input port of the sludge conveying and drying device 1. The drying flue gas output port of the sludge conveying and drying device 1 is connected to the input port of the drying flue gas circulation device 4. The output port of the drying flue gas circulation device 4 is divided into two branches. The high-temperature heat exchanger 3 is provided with a first receiving chamber and a second receiving chamber. The first receiving chamber is used to receive the drying flue gas, and the second receiving chamber is used to receive the incineration flue gas. The drying flue gas and the incineration flue gas are heat-exchanged in the high-temperature heat exchanger 3. One of the branches of the output port of the drying flue gas circulation device 4 enters The first receiving chamber of the high-temperature heat exchanger 3 is used to exchange heat between part of the incineration flue gas and the drying flue gas, and then pass it through the external exhaust gas treatment equipment 6 connected to the output end of the high-temperature heat exchanger 3 to provide heat for the external exhaust gas treatment equipment 6, ensuring that the drying flue gas is always in a gaseous state and is directly discharged outdoors through the chimney without producing condensed liquid. Another branch of the output port of the drying flue gas circulation device 4 is directly mixed with the incineration flue gas discharged from the second receiving chamber of the high-temperature heat exchanger 3 and then enters the incineration cycle in the incinerator 2 to prevent the high-temperature heat exchanger 3 from being overloaded and the mixed flue gas temperature entering the incinerator 2 being too low, affecting the incineration efficiency. An air inlet is provided at the bottom of the incinerator 2, and a main fan 5 is connected to the air inlet. The main fan 5 is used to provide combustion-supporting oxygen for the incinerator 2. The sludge The sludge output port of the conveying and drying device 1 is connected to the sludge input port of the incinerator 2. After the sludge contacts the high-temperature incineration flue gas output by the incinerator 2 in the sludge conveying and drying device 1, it is rotated and dried and then output to the incinerator 2 as a combustion medium. The sludge conveying and drying device 1 includes a sludge conveyor 11, a sludge rotary dryer 12, a drying tower 13, and a bag dust collector 14. A high-temperature air inlet channel 121 is provided at one end above the sludge rotary dryer 12. The higher the temperature at the high-temperature air inlet channel 121, the higher the rotation efficiency inside the sludge rotary dryer 12. One end of the incineration flue gas output port of the incinerator 2 is connected to the high-temperature air inlet channel 121. A drying tower 13 is provided at the other end above the sludge rotary dryer 12. The drying tower 13 is used to dry the sludge. The sludge is dried and the treated sludge and high-temperature drying flue gas are discharged. The external sludge output device is connected to the sludge input port of the sludge conveyor 11. The sludge output port of the sludge conveyor 11 is connected to the sludge input port of the sludge rotary dryer 12. The sludge output port of the sludge rotary dryer 12 is connected to the sludge input port of the drying tower 13. The sludge output port of the drying tower 13 is connected to the sludge input port of the bag dust collector 14. The bag dust collector 14 is used to receive the sludge and the drying flue gas for solid-gas separation and then discharge them separately. The sludge output port of the bag dust collector 14 is connected to the sludge input port of the incinerator 2. The drying flue gas output port of the bag dust collector 14 is connected to the input port of the drying flue gas circulation device 4. The side of the high-temperature air inlet channel 121 is also provided with an emergency cooling device 122.It is used for emergency cooling of the high-temperature air inlet channel 121 in case of failure. A first liquid-cooled feeder 15 is also provided between the sludge outlet of the bag-type dust collector 14 and the sludge inlet connecting pipe of the incinerator 2, which is used to quantitatively output the sludge after solid-liquid separation to the incinerator 2 and play a role of air sealing. The drying flue gas circulation device 4 includes a drying circulation induced draft fan 41. The drying flue gas outlet of the bag-type dust collector 14 is connected to the drying flue gas inlet of the drying circulation induced draft fan 41. The drying flue gas outlet of the drying circulation induced draft fan 41 is connected to the drying flue gas inlet of the first receiving chamber of the high-temperature heat exchanger 3. A first regulating valve 16 is provided on the connecting pipe for controlling the drying flue gas output. The outlet of the drying flue gas circulation device 4 is directly mixed with the incineration flue gas discharged from the second receiving chamber of the high-temperature heat exchanger 3. The first bypass regulating pipe 31 is provided with a second regulating valve 32 for assisting in regulating the output of the drying flue gas. When the high-temperature heat exchanger 3 is overloaded, the second regulating valve 32 opens to disperse the gas volume in the first bypass regulating pipe 31, and at the same time, the temperature of the mixed flue gas entering the incinerator 2 is not too low. The drying flue gas output port of the drying circulation induced draft fan 41 is connected to the drying flue gas input port of the first receiving chamber, the drying flue gas output port of the first receiving chamber is connected to the drying flue gas input port of the incinerator 2, the combustion flue gas output port of the incinerator 2 is connected to the combustion flue gas input port of the second receiving chamber, and the combustion flue gas output port of the first receiving chamber is connected to the input port of the external exhaust gas treatment equipment 6. The sludge conveyor 11 and the sludge rotary dryer 12 are both spiral feeders.

[0029] Beneficial effects of the invention: The invention proposes a sludge drying and incineration closed-loop circulation system, comprising a sludge drying feeding device 1, an incinerator 2, a high-temperature heat exchanger 3, a drying flue gas circulation device 4, and a main fan 5. The sludge drying feeding device 1, the incinerator 2, the high-temperature heat exchanger 3, the drying flue gas circulation device 4, and the main fan 5 form a short-stroke, wind speed, and wind pressure closed-loop circulation system. The 850°C incineration flue gas discharged from the incinerator 2 enters the high-temperature heat exchanger 3 and the sludge rotary dryer 12 respectively. The 850°C incineration flue gas is directly dried by high-temperature direct contact with the sludge in the sludge rotary dryer 12 to form flue gas containing harmful gases such as VOC and sulfur dioxide. The harmful flue gas is input into the incinerator 2 for incineration and recycling, thereby solving the problem of difficult treatment of emission gas pollution, effectively utilizing the drying flue gas output by the sludge drying feeding device 1, reducing the resource waste rate and improving The drying efficiency of the sludge drying feeding device 1 is improved, and the short stroke also reduces the concentration of flammable and explosive substances contained in the drying flue gas, and the probability of increased retention in the circulation pipeline to form a safety hazard, thereby improving the safe operation rate. One of the branches of the output port of the drying flue gas circulation device 4 enters the first receiving chamber of the high-temperature heat exchanger 3, which is used to exchange heat between part of the incineration flue gas and the drying flue gas, and then passes through the external exhaust gas treatment equipment 6 connected to the output end of the high-temperature heat exchanger 3 to provide heat for the external gas treatment equipment 6, ensuring that the drying flue gas is always in a gaseous state and is directly discharged to the outdoors through the chimney without producing condensed liquid. Another branch of the output port of the drying flue gas circulation device 4 is directly mixed with the incineration flue gas discharged from the second receiving chamber of the high-temperature heat exchanger 3 and then enters the incineration cycle in the incinerator 2 to prevent the high-temperature heat exchanger 3 from being overloaded and the mixed flue gas temperature entering the incinerator 2 being too low, thereby affecting the incineration efficiency.

[0030] Working principle of the present invention:

[0031] First, the combustion flue gas of the incinerator 2 is transported to the high-temperature heat exchanger 22 and the high-temperature air inlet channel 121 respectively. The temperature of the flue gas is 850°C when it is transported to the second receiving chamber of the high-temperature heat exchanger 22, and the temperature of the flue gas is 300°C-750°C when it is transported to the high-temperature air inlet channel 121.

[0032] Secondly, the sludge is input into the sludge conveyor 11 by external equipment. The sludge conveyor 11 sequentially passes the sludge through the sludge rotary dryer 12, the drying tower 13, and the bag dust collector 14.

[0033] Specifically, the sludge in the sludge rotary dryer 12 contacts the incineration flue gas with a temperature of 300℃-750℃ in the high-temperature air inlet channel 121 to complete preliminary drying, and then the sludge and the dried flue gas enter the bag dust collector 14 through the drying tower 13, and the sludge enters the incinerator 2 through the first liquid-cooled feeder 15 to become a combustion medium, and the dried flue gas (harmful gas flue gas such as VOC and sulfur dioxide) is output from the drying flue gas output port of the bag dust collector 14 to the drying circulation induced draft fan 41.

[0034] Finally, the drying circulation induced draft fan 41 outputs a part of the drying flue gas to the high-temperature heat exchanger 3, and the high-temperature heat exchanger 3 outputs the incineration flue gas to the input port of the external exhaust gas treatment equipment 6 after the heat exchange is completed; the other part of the drying flue gas is directly mixed with the incineration flue gas discharged from the second receiving chamber of the high-temperature heat exchanger 3 and then enters the incineration cycle in the incinerator 2 to prevent the high-temperature heat exchanger 3 from being overloaded and the mixed flue gas temperature entering the incinerator 2 being too low, which affects the incineration efficiency.

[0035] Specifically, the drying circulation induced draft fan 41 inputs the drying flue gas at 100℃-180℃ into the second receiving chamber of the high-temperature heat exchanger 22, and the drying flue gas at 100℃-180℃ undergoes heat exchange in the first receiving chamber with the second receiving chamber at 850℃, so that the drying flue gas at 100℃-180℃ is raised to a gas at no less than 150℃-180℃ and enters the external exhaust gas treatment equipment 6, ensuring that the drying flue gas is always in a gaseous state and is directly discharged outdoors through the chimney without producing condensed liquid.

[0036] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A sludge drying and incineration closed-loop circulation system, comprising a sludge conveying and drying device (1), an incinerator (2), a high-temperature heat exchanger (3), and a drying flue gas circulation device (4), characterized in that: The combustion flue gas output port of the incinerator (2) is respectively connected to the combustion flue gas input port of the high-temperature heat exchanger (3) and the combustion flue gas input port of the sludge conveying and drying device (1), the drying flue gas output port of the sludge conveying and drying device (1) is connected to the drying flue gas circulation device (4) input port, the drying flue gas circulation device (4) output port is divided into two branches, the high-temperature heat exchanger (3) is provided with a first receiving chamber and a second receiving chamber, the first receiving chamber is used to receive the drying flue gas, the second receiving chamber is used to receive the combustion flue gas, the drying flue gas and the combustion flue gas are heat exchanged in the high-temperature heat exchanger (3), and the drying flue gas circulation device (4) is connected to the drying flue gas circulation device (4) input port. One of the branches of the output port of the circulation device (4) enters the first receiving chamber of the high-temperature heat exchanger (3), and is used to exchange heat between part of the incineration flue gas and the drying flue gas, and then pass through the external exhaust gas treatment equipment (6) connected to the output end of the high-temperature heat exchanger (3), so as to provide heat for the external exhaust gas treatment equipment (6). Another branch of the output port of the drying flue gas circulation device (4) is directly mixed with the incineration flue gas discharged from the second receiving chamber of the high-temperature heat exchanger (3) and then enters the incinerator (3) for incineration and recycling, so as to prevent the high-temperature heat exchanger (3) from being overloaded and the mixed flue gas entering the incinerator (2) from being too low in temperature.

2. The sludge drying and incineration closed-loop circulation system according to claim 1, characterized in that: An air inlet is provided at the bottom of the incinerator (2), and a main fan (5) is connected to the air inlet. The main fan (5) is used to provide combustion-supporting oxygen for the incinerator (2).

3. The sludge drying and incineration closed-loop circulation system according to claim 1, characterized in that: The sludge output port of the sludge conveying and drying device (1) is connected to the sludge input port of the incinerator (2). After the sludge contacts the high-temperature combustion flue gas output by the incinerator (2) in the sludge conveying and drying device (1), it is rotated and dried and then output to the incinerator (2) to become a combustion medium.

4. The sludge drying and incineration closed-loop circulation system according to claim 1, characterized in that: The sludge conveying and drying device (1) comprises a sludge conveyor (11), a sludge rotary dryer (12), a drying tower (13), and a bag dust collector (14). A high-temperature air inlet passage (121) is provided at one end above the sludge rotary dryer (12). One end of the combustion flue gas outlet of the incinerator (2) is connected to the high-temperature air inlet passage (121). A drying tower (13) is provided at the other end above the sludge rotary dryer (12). The drying tower (13) is used to dry the sludge and discharge the treated sludge and the high-temperature drying flue gas. The external sludge output device is connected to the sludge input port of the sludge conveyor (11). The sludge outlet of the sludge conveyor (11) is connected to the sludge input port of the sludge rotary dryer (12), the sludge outlet of the sludge rotary dryer (12) is connected to the sludge input port of the drying tower (13), the sludge outlet of the drying tower (13) is connected to the sludge input port of the bag dust collector (14), the bag dust collector (14) is used to receive the sludge and the drying flue gas for solid-gas separation and then discharge them separately, the sludge outlet of the bag dust collector (14) is connected to the sludge input port of the incinerator (2), and the drying flue gas outlet of the bag dust collector (14) is connected to the input port of the drying flue gas circulation device (4).

5. The sludge drying and incineration closed-loop circulation system according to claim 2, characterized in that: An emergency cooling device (122) is also provided on the side of the high-temperature air intake passage (121) for emergency cooling of the high-temperature air intake passage (121) in the event of a fault.

6. The sludge drying and incineration closed-loop circulation system according to claim 2, characterized in that: A first liquid-cooled feeder (15) is also provided between the connecting pipe between the sludge outlet of the bag filter (14) and the sludge inlet of the incinerator (2), for quantitatively outputting the sludge after solid-liquid separation to the incinerator (2) and also serving as an air seal.

7. The sludge drying and incineration closed-loop circulation system according to claim 1, characterized in that: The drying flue gas circulation device (4) comprises a drying circulation induced draft fan (41), the drying flue gas output port of the bag filter (14) is connected to the drying flue gas input port of the drying circulation induced draft fan (41), and a first regulating valve (16) is provided on the connecting pipe between the drying flue gas output port of the drying circulation induced draft fan (41) and the drying flue gas input port of the first receiving chamber of the high-temperature heat exchanger (3), for controlling the drying flue gas output amount.

8. The sludge drying and incineration closed-loop circulation system according to claim 5, characterized in that: Another branch for directly mixing the incineration flue gas discharged from the output port of the drying flue gas circulation device (4) and the second receiving chamber of the high-temperature heat exchanger (3) is a first bypass regulating pipe (31). The first bypass regulating pipe (31) is provided with a second regulating valve (32) for assisting in regulating the output of the drying flue gas. When the high-temperature heat exchanger (3) is overloaded, the second regulating valve (32) opens to disperse the gas volume in the first bypass regulating pipe (31), and at the same time, the temperature of the mixed flue gas entering the incinerator (2) is not too low.

9. The sludge drying and incineration closed-loop circulation system according to claim 1, characterized in that: The drying smoke output port of the drying circulation induced draft fan (41) is connected to the drying smoke input port of the first receiving chamber, the drying smoke output port of the first receiving chamber is connected to the drying smoke input port of the incinerator (2), the combustion smoke output port of the incinerator (2) is connected to the combustion smoke input port of the second receiving chamber, and the combustion smoke output port of the first receiving chamber is connected to the input port of the external exhaust gas treatment equipment (6).

10. The sludge drying and incineration closed-loop circulation system according to claim 1, characterized in that: The sludge conveyor (11) and the sludge rotary dryer (12) are both feeders with a spiral structure.

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