A sludge drying and pyrolysis process gas treatment system and treatment method

Abstract

The present invention discloses a sludge drying and pyrolysis process gas treatment system and treatment method. The drying treatment subsystem includes a drying tank, a drying gas filter, a drying gas condenser, a pyrolysis water storage tank, and a drying gas blower, which are connected in sequence. The medium-temperature pyrolysis treatment subsystem includes a medium-temperature pyrolysis tank, a pyrolysis oil vapor filter, a pyrolysis oil vapor condenser, a pyrolysis heavy oil storage tank, and a pyrolysis oil vapor blower, which are connected in sequence. The sludge inlet of the medium-temperature pyrolysis tank is connected to the sludge outlet of the drying tank. The high-temperature pyrolysis treatment subsystem includes a high-temperature pyrolysis tank, a pyrolysis gas filter, a pyrolysis gas condenser, a pyrolysis light oil storage tank, and a pyrolysis gas blower. The sludge inlet of the high-temperature pyrolysis tank is connected to the sludge outlet of the medium-temperature pyrolysis tank. The pyrolysis gas treatment subsystem is respectively connected to the drying gas blower, the pyrolysis oil vapor blower, and the pyrolysis gas blower. The gas product characteristics of the present invention are relatively simple and stable, easy to handle, and can improve processing efficiency, heat utilization rate, and system stability.

Description

Technical Field

[0001] The present invention relates to a sludge treatment system, and in particular to a sludge drying and pyrolysis process gas treatment system and treatment method. Background Art

[0002] The main organic solid wastes currently treated by pyrolysis include municipal sludge and industrial oil sludge. Sludge is characterized by high yield, high moisture content, and high pollution. Sludge contains a large number of pathogenic bacteria, parasite eggs, viruses, heavy metals, and other harmful substances. During storage, transportation, and processing, it is very easy to produce leachate that contaminates groundwater and emits harmful gases that pollute the surrounding environment. Currently, single anaerobic treatment, drying incineration, and composting are the most commonly used treatment methods, but these methods have problems such as incomplete treatment and secondary pollution transfer. The sludge drying and pyrolysis process can effectively solve these problems.

[0003] Existing sludge pyrolysis processes use relatively crude methods to dispose of the gases produced. For example, the pyrolysis gas produced by most pyrolysis furnaces is fed directly into burners. Due to the unstable gas content, direct combustion can easily clog pipes and equipment. Furthermore, sludge contains a high water content, and the gaseous products have a low calorific value. Direct combustion in burners can result in unstable and unreliable combustion. For example, when the moisture content of the sludge feedstock is between 30% and 40%, water vapor can make up as much as 60% to 80% of the gaseous products produced by pyrolysis. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, on the one hand, the present invention provides a sludge drying pyrolysis process gas treatment system that can extract the pyrolysis process gas for targeted treatment to improve heat utilization and stability.

[0005] On the other hand, the present invention also provides a method for treating gas from a sludge drying and pyrolysis process.

[0006] According to an embodiment of the first aspect of the present invention, a sludge drying and pyrolysis process gas treatment system includes a drying treatment subsystem, a medium-temperature pyrolysis treatment subsystem, a high-temperature pyrolysis treatment subsystem, and a pyrolysis gas treatment subsystem. The drying treatment subsystem includes a drying tank, a drying gas filter, a drying gas condenser, a pyrolysis water storage tank, and a drying gas blower connected in sequence, and the drying tank is provided with a sludge inlet. The medium-temperature pyrolysis treatment subsystem includes a medium-temperature pyrolysis tank, a pyrolysis oil vapor filter, a pyrolysis oil vapor condenser, a pyrolysis heavy oil storage tank, and a pyrolysis oil vapor blower connected in sequence, and the sludge inlet of the medium-temperature pyrolysis tank is connected to the sludge outlet of the drying tank. The high-temperature pyrolysis treatment subsystem includes a high-temperature pyrolysis tank, a pyrolysis gas filter, a pyrolysis gas condenser, a pyrolysis light oil storage tank, and a pyrolysis gas blower, and the sludge inlet of the high-temperature pyrolysis tank is connected to the sludge outlet of the medium-temperature pyrolysis tank. The pyrolysis gas processing subsystem is respectively connected to the drying gas blower, the pyrolysis oil vapor blower, and the pyrolysis gas blower, and is used to process the generated drying gas, pyrolysis oil vapor, and pyrolysis gas and transmit the heat energy generated during the processing to the drying tank, the medium-temperature pyrolysis tank, and the high-temperature pyrolysis tank.

[0007] A sludge drying and pyrolysis process gas treatment system according to the first embodiment of the present invention has at least the following beneficial effects:

[0008] The invention, applying the above-mentioned embodiments, utilizes a three-stage extraction process for pyrolysis process gases, using a drying tank, a medium-temperature pyrolysis tank, and a high-temperature pyrolysis tank. The pyrolysis process gases generated at different stages are extracted and processed according to their characteristics. Specifically, the dry gas generated by the drying tank is filtered and condensed to remove water vapor and then fed to the pyrolysis gas treatment subsystem. The pyrolysis oil vapor generated by the medium-temperature pyrolysis tank is filtered and condensed to remove heavy condensed oil and then fed to the pyrolysis gas treatment subsystem. The pyrolysis gas generated by the high-temperature pyrolysis tank is filtered and condensed to remove light condensed oil and then fed to the pyrolysis gas treatment subsystem. Because the pyrolysis process gases are extracted in stages, the gaseous products have relatively uniform and stable characteristics, making them easier to process. The post-processing equipment for the pyrolysis process gases extracted in stages is much smaller than that for non-stage extraction, making it easier to operate and maintain. Furthermore, since the pyrolysis water vapor is generated and extracted from the drying tank at a relatively low process temperature, it carries less heat than a single pyrolysis unit. This increases the heat carried by the pyrolysis gas, thereby improving heat utilization. The present invention can improve processing efficiency, increase heat utilization rate, and enhance the stability, reliability, and sustainability of the system.

[0009] According to some embodiments of the present invention, the pyrolysis gas processing subsystem is provided with a pyrolysis gas burner and an auxiliary burner. The pyrolysis gas burner is connected to the drying gas blower, the pyrolysis oil vapor blower and the pyrolysis gas blower. The hot flue gas outlets of the pyrolysis gas burner and the auxiliary burner are connected in parallel to the drying tank, the medium-temperature pyrolysis tank and the high-temperature pyrolysis tank; the auxiliary burner is provided with a natural gas inlet.

[0010] According to some embodiments of the present invention, the tank bodies of the drying tank, the medium-temperature pyrolysis tank, and the high-temperature pyrolysis tank are all provided with a first interlayer structure, and the pyrolysis gas treatment subsystem is connected to the first interlayer structure of the drying tank, the medium-temperature pyrolysis tank, and the high-temperature pyrolysis tank.

[0011] According to some embodiments of the present invention, a gas storage cabinet is provided between the pyrolysis light oil storage tank and the pyrolysis gas blower, and the gas storage cabinet is used to control the discharge volume of the pyrolysis gas.

[0012] According to some embodiments of the present invention, the temperature of the drying tank is less than 200°C.

[0013] According to some embodiments of the present invention, the temperature of the medium-temperature pyrolysis tank is 200°C to 400°C.

[0014] According to some embodiments of the present invention, the temperature of the high-temperature pyrolysis tank is 400°C to 600°C.

[0015] According to some embodiments of the present invention, the sludge drying and pyrolysis process gas treatment system further includes a cooling tank, and a sludge inlet of the cooling tank is connected to a sludge outlet of the high-temperature pyrolysis tank.

[0016] According to some embodiments of the present invention, the tank body of the cooling tank is provided with a second sandwich structure, and the second sandwich structure is used for passing a cooling medium.

[0017] According to a second aspect of an embodiment of the present invention, a method for treating sludge drying and pyrolysis process gas, using the sludge drying and pyrolysis process gas treatment system described in the above embodiment, comprises the following steps:

[0018] The sludge is dried in the drying tank, and the dry gas is drawn out by the dry gas blower, filtered and condensed by the dry gas filter and the dry gas condenser to remove water vapor, and the remaining small amount of non-condensable dry gas is sent to the pyrolysis gas treatment subsystem for treatment;

[0019] The dried sludge is fed into the medium-temperature pyrolysis tank, and the pyrolysis oil vapor blower draws out heavy pyrolysis oil vapor, which is filtered and condensed by the pyrolysis oil vapor filter and the pyrolysis oil vapor condenser to remove the heavy condensed oil. The remaining small amount of pyrolysis oil vapor is fed into the pyrolysis gas treatment subsystem for treatment;

[0020] The sludge after medium-temperature pyrolysis is sent to the high-temperature pyrolysis tank, and the pyrolysis gas blower draws out light pyrolysis oil vapor and pyrolysis gas, which are filtered and condensed by the pyrolysis gas filter and the pyrolysis gas condenser to remove the light condensed oil, and the remaining pyrolysis gas is sent to the pyrolysis gas treatment subsystem for treatment;

[0021] The heat energy generated by the pyrolysis gas treatment subsystem is fed back to the drying tank, the medium-temperature pyrolysis tank and the high-temperature pyrolysis tank.

[0022] A method for treating sludge drying and pyrolysis process gas according to the second embodiment of the present invention has at least the following beneficial effects:

[0023] The gas products of the pyrolysis process gas extracted by graded extraction have relatively simple and stable characteristics and are easy to handle. The post-processing device for the pyrolysis process gas extracted by graded extraction is much smaller in scale than the post-processing device for ungraded extraction. In graded extraction, the post-processing device is easier to operate and maintain. In addition, the pyrolysis water vapor is generated and drawn out from the drying tank with a relatively low process temperature. The heat carried away by the water vapor is less than that in a single pyrolysis device process, thereby increasing the heat carried by the pyrolysis gas, which is beneficial to improving the thermal utilization rate. The present invention can improve processing efficiency, improve thermal utilization rate, and improve the stability, reliability, and sustainability of the system.

[0024] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0026] Figure 1 This is a schematic diagram of an embodiment of a sludge drying and pyrolysis process gas treatment system of the present invention;

[0027] Figure 2 This is a schematic diagram of another embodiment of a sludge drying and pyrolysis process gas treatment system of the present invention;

[0028] Figure Number:

[0029] 110. Drying tank; 111. Drying gas filter; 112. Drying gas condenser; 113. Pyrolysis water storage tank; 114. Drying gas fan;

[0030] 120. Medium-temperature pyrolysis tank; 121. Pyrolysis oil vapor filter; 122. Pyrolysis oil vapor condenser; 123. Pyrolysis heavy oil storage tank; 124. Pyrolysis oil vapor blower;

[0031] 130. High-temperature pyrolysis tank; 131. Pyrolysis gas filter; 132. Pyrolysis gas condenser; 133. Pyrolysis light oil storage tank; 134. Pyrolysis gas blower; 135. Gas storage cabinet;

[0032] 140. Pyrolysis burner; 141. Auxiliary burner;

[0033] 150. Cooling tank. DETAILED DESCRIPTION

[0034] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0035] In the description of the present invention, it should be understood that descriptions involving orientation, such as the orientation or positional relationship indicated by up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0037] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0038] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0039] Reference Figure 1As shown, a sludge drying and pyrolysis process gas treatment system according to an embodiment of the present invention includes a drying treatment subsystem, a medium-temperature pyrolysis treatment subsystem, a high-temperature pyrolysis treatment subsystem, and a pyrolysis gas treatment subsystem. The drying treatment subsystem includes a drying tank 110, a drying gas filter 111, a drying gas condenser 112, a pyrolysis water storage tank 113, and a drying gas blower 114, which are connected in sequence. The drying tank 110 is provided with a sludge inlet. The medium-temperature pyrolysis treatment subsystem includes a medium-temperature pyrolysis tank 120, a pyrolysis oil vapor filter 121, a pyrolysis oil vapor condenser 122, a pyrolysis heavy oil storage tank 123, and a pyrolysis oil vapor blower 124, which are connected in sequence. The sludge inlet of the medium-temperature pyrolysis tank 120 is connected to the sludge outlet of the drying tank 110. The high-temperature pyrolysis treatment subsystem includes a high-temperature pyrolysis tank 130, a pyrolysis gas filter 131, a pyrolysis gas condenser 132, a pyrolysis light oil storage tank 133, and a pyrolysis gas blower 134. The sludge inlet of the high-temperature pyrolysis tank 130 is connected to the sludge outlet of the medium-temperature pyrolysis tank 120. The pyrolysis gas treatment subsystem is connected to the drying gas blower 114, the pyrolysis oil vapor blower 124, and the pyrolysis gas blower 134, respectively, to process the generated drying gas, pyrolysis oil vapor, and pyrolysis gas, and to deliver the heat energy generated during the treatment process to the drying tank 110, the medium-temperature pyrolysis tank 120, and the high-temperature pyrolysis tank 130.

[0040] The invention using the above-mentioned embodiment adopts a three-stage extraction process of pyrolysis process gas using a drying tank 110, a medium-temperature pyrolysis tank 120, and a high-temperature pyrolysis tank 130. The pyrolysis process gas generated in different process stages is extracted separately according to its characteristics and processed in a targeted manner. Specifically, the dry gas generated by the drying tank 110 is filtered and condensed to remove water vapor and sent to the pyrolysis gas treatment subsystem for treatment. The pyrolysis oil vapor generated by the medium-temperature pyrolysis tank 120 is filtered and condensed to remove heavy condensed oil and sent to the pyrolysis gas treatment subsystem for treatment. The pyrolysis gas generated by the high-temperature pyrolysis tank 130 is filtered and condensed to remove light condensed oil and sent to the pyrolysis gas treatment subsystem for treatment. Because the pyrolysis process gas is extracted in stages, the gas product characteristics are relatively simple and stable, making it easy to process. The post-processing device for the pyrolysis process gas extracted in stages is much smaller in scale than the post-processing device for non-stage extraction. In staged extraction, the post-processing device is more convenient to operate and maintain. Furthermore, pyrolysis water vapor is generated and drawn out of the drying tank 110, where the process temperature is relatively low. This water vapor removes less heat than a single pyrolysis unit process, thereby increasing the heat carried by the pyrolysis gas and improving heat utilization. This invention can improve processing efficiency, increase heat utilization, and enhance the stability, reliability, and sustainability of the system.

[0041] Reference Figure 1As shown, it can be understood that the pyrolysis gas processing subsystem is equipped with a pyrolysis gas burner and an auxiliary burner 141. The pyrolysis gas burner is connected to the drying gas blower 114, the pyrolysis oil vapor blower 124, and the pyrolysis gas blower 134. The hot flue gas outlets of the pyrolysis gas burner and the auxiliary burner 141 are connected in parallel to the drying tank 110, the medium-temperature pyrolysis tank 120, and the high-temperature pyrolysis tank 130. The auxiliary burner 141 is equipped with a natural gas inlet. During the initial startup of the system of this embodiment, there is no pyrolysis gas as a heat source, so the auxiliary burner 141 is provided with an external natural gas heat source. In addition, during system operation, if the pyrolysis gas is insufficient or fluctuates, the auxiliary burner 141 can be turned on to stabilize operation.

[0042] It can be understood that the tank bodies of the drying tank 110, the medium-temperature pyrolysis tank 120 and the high-temperature pyrolysis tank 130 are all provided with a first interlayer structure, and the pyrolysis gas processing subsystem is connected to the first interlayer structure of the drying tank 110, the medium-temperature pyrolysis tank 120 and the high-temperature pyrolysis tank 130.

[0043] Reference Figure 1 As shown, it can be understood that during the pyrolysis process, the generation of pyrolysis gas is unstable. Generally speaking, it is less in the early stage, more in the middle stage, and less in the late stage. Therefore, in order to maintain a stable load during the entire operation cycle, a gas storage cabinet 135 is provided between the pyrolysis light oil storage tank 133 and the pyrolysis gas blower 134. The gas storage cabinet 135 is used to control the discharge volume of the pyrolysis gas. By regularly releasing and burning the gas, the amount and load size can be well controlled.

[0044] It is understood that the temperature of the drying tank 110 is less than 200°C.

[0045] It is understandable that the temperature of the medium-temperature pyrolysis tank 120 is 200°C to 400°C.

[0046] It is understood that the temperature of the high-temperature pyrolysis tank 130 is 400°C to 600°C.

[0047] It is understandable that the sludge drying and pyrolysis process gas treatment system further includes a cooling tank 150 , and the sludge inlet of the cooling tank 150 is connected to the sludge outlet of the high-temperature pyrolysis tank 130 .

[0048] It can be understood that the tank body of the cooling tank 150 is provided with a second interlayer structure, and the second interlayer structure is used to pass a cooling medium. Specifically, the cooling medium can be cold air or cooling water.

[0049] Reference Figure 2 As shown, it can be understood that when the water content of organic solid waste such as sludge is very low, the drying gas process can be omitted. The system consists of a medium-temperature pyrolysis tank 120, a high-temperature pyrolysis tank 130, and a cooling tank 150. Pyrolysis produces heavy pyrolysis oil vapor and pyrolysis gas. The two pyrolysis process gases with different characteristics are independently drawn out for treatment.

[0050] According to a second aspect of an embodiment of the present invention, a method for treating sludge drying and pyrolysis process gas, using the sludge drying and pyrolysis process gas treatment system of the above embodiment, comprises the following steps:

[0051] The sludge is dried in the drying tank 110. Dry gas is drawn out by the dry gas blower 114 and filtered and condensed by the dry gas filter 111 and the dry gas condenser 112 to remove water vapor. The remaining small amount of non-condensable dry gas is sent to the pyrolysis gas treatment subsystem for treatment.

[0052] The dried sludge is sent to the medium-temperature pyrolysis tank 120, and the pyrolysis oil vapor blower 124 draws out the heavy pyrolysis oil vapor, which is filtered and condensed by the pyrolysis oil vapor filter 121 and the pyrolysis oil vapor condenser 122 to remove the heavy condensed oil. The remaining small amount of pyrolysis oil vapor is sent to the pyrolysis gas treatment subsystem for treatment;

[0053] The sludge after medium-temperature pyrolysis is sent to the high-temperature pyrolysis tank 130. The pyrolysis gas blower 134 draws out light pyrolysis oil vapor and pyrolysis gas. After filtering and condensing through the pyrolysis gas filter 131 and the pyrolysis gas condenser 132, the light condensed oil is removed, and the remaining pyrolysis gas is sent to the pyrolysis gas treatment subsystem for treatment.

[0054] The heat energy generated by the pyrolysis gas processing subsystem is fed back to the drying tank 110 , the medium-temperature pyrolysis tank 120 and the high-temperature pyrolysis tank 130 .

[0055] The pyrolysis process gas extracted in stages using the sludge drying pyrolysis process gas treatment method of the present invention has relatively simple and stable gas product characteristics and is easy to handle. The post-processing device for the pyrolysis process gas extracted in stages is much smaller in scale than the post-processing device for unstaged extraction. During staged extraction, the post-processing device is easier to operate and maintain. In addition, the pyrolysis water vapor is generated and drawn out from the drying tank 110, which has a relatively low process temperature. The heat carried away by the water vapor is less than that in a single pyrolysis device process, thereby increasing the heat carried by the pyrolysis gas, which is beneficial to improving the heat utilization rate. The present invention can improve processing efficiency, improve heat utilization rate, and improve the stability, reliability, and sustainability of the system.

[0056] Throughout this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" indicate that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0057] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A sludge drying and pyrolysis process gas treatment system, characterized in that: include: A drying processing subsystem, the drying processing subsystem comprising a drying tank, a drying gas filter, a drying gas condenser, a pyrolysis water storage tank and a drying gas blower connected in sequence, the drying tank being provided with a sludge inlet; A medium-temperature pyrolysis treatment subsystem, comprising a medium-temperature pyrolysis tank, a pyrolysis oil vapor filter, a pyrolysis oil vapor condenser, a pyrolysis heavy oil storage tank, and a pyrolysis oil vapor blower connected in sequence, wherein the sludge inlet of the medium-temperature pyrolysis tank is connected to the sludge outlet of the drying tank, the temperature of the medium-temperature pyrolysis tank is 200°C to 400°C, and the product of the medium-temperature pyrolysis tank includes heavy pyrolysis oil vapor; A high-temperature pyrolysis treatment subsystem, comprising a high-temperature pyrolysis tank, a pyrolysis gas filter, a pyrolysis gas condenser, a pyrolysis light oil storage tank, and a pyrolysis gas blower. The sludge inlet of the high-temperature pyrolysis tank is connected to the sludge outlet of the medium-temperature pyrolysis tank. The temperature of the high-temperature pyrolysis tank is 400°C to 600°C. The products of the high-temperature pyrolysis tank include light pyrolysis oil vapor and pyrolysis gas. as well as The pyrolysis gas treatment subsystem is connected to the drying gas blower, the pyrolysis oil vapor blower, and the pyrolysis gas blower respectively, and is used to process the generated drying gas, pyrolysis oil vapor, and pyrolysis gas and transmit the heat energy generated during the treatment process to the drying tank, the medium-temperature pyrolysis tank, and the high-temperature pyrolysis tank.

2. The sludge drying and pyrolysis process gas treatment system according to claim 1, characterized in that: The pyrolysis gas treatment subsystem is provided with a pyrolysis gas burner and an auxiliary burner. The pyrolysis gas burner is connected to the drying gas blower, the pyrolysis oil vapor blower and the pyrolysis gas blower. The hot flue gas outlets of the pyrolysis gas burner and the auxiliary burner are connected in parallel to the drying tank, the medium-temperature pyrolysis tank and the high-temperature pyrolysis tank; the auxiliary burner is provided with a natural gas inlet.

3. The sludge drying and pyrolysis process gas treatment system according to claim 2, characterized in that: The tank bodies of the drying tank, the medium-temperature pyrolysis tank and the high-temperature pyrolysis tank are all provided with a first sandwich structure, and the pyrolysis gas processing subsystem is connected to the first sandwich structure of the drying tank, the medium-temperature pyrolysis tank and the high-temperature pyrolysis tank.

4. The sludge drying and pyrolysis process gas treatment system according to claim 1, characterized in that: A gas storage cabinet is provided between the pyrolysis light oil storage tank and the pyrolysis gas blower, and the gas storage cabinet is used to control the discharge volume of the pyrolysis gas.

5. The sludge drying and pyrolysis process gas treatment system according to claim 1, characterized in that: The temperature of the drying tank is less than 200°C.

6. The sludge drying and pyrolysis process gas treatment system according to claim 1, characterized in that: The sludge drying and pyrolysis process gas treatment system further includes a cooling tank, wherein the sludge inlet of the cooling tank is connected to the sludge outlet of the high-temperature pyrolysis tank.

7. The sludge drying and pyrolysis process gas treatment system according to claim 6, characterized in that: The tank body of the cooling tank is provided with a second sandwich structure, and the second sandwich structure is used for passing cooling medium.

8. A method for treating gas from a sludge drying and pyrolysis process, characterized by: The sludge drying and pyrolysis process gas treatment system according to any one of claims 1 to 7 comprises the following steps: The sludge is dried in the drying tank, and the dry gas is drawn out by the dry gas blower, filtered and condensed by the dry gas filter and the dry gas condenser to remove water vapor, and the remaining small amount of non-condensable dry gas is sent to the pyrolysis gas treatment subsystem for treatment; The dried sludge is fed into the medium-temperature pyrolysis tank, and the pyrolysis oil vapor blower draws out heavy pyrolysis oil vapor, which is filtered and condensed by the pyrolysis oil vapor filter and the pyrolysis oil vapor condenser to remove the heavy condensed oil. The remaining small amount of pyrolysis oil vapor is fed into the pyrolysis gas treatment subsystem for treatment; The sludge after medium-temperature pyrolysis is sent to the high-temperature pyrolysis tank, and the pyrolysis gas blower draws out light pyrolysis oil vapor and pyrolysis gas, which are filtered and condensed by the pyrolysis gas filter and the pyrolysis gas condenser to remove the light condensed oil, and the remaining pyrolysis gas is sent to the pyrolysis gas treatment subsystem for treatment; The heat energy generated by the pyrolysis gas processing subsystem is fed back to the drying tank, the medium-temperature pyrolysis tank and the high-temperature pyrolysis tank.

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