Sludge separation type heat exchange drying and carbonization process

Abstract

The application discloses a sludge separation type heat exchange drying and carbonization process applied to the technical field of sludge drying, and heat exchange of heat of flue gas at an outlet of a carbonization furnace jacket is carried out through two mediums, namely, a heat conducting rod and deionized water, and is isothermally and efficiently transferred to a drying disc for indirect drying of sludge, so that problems of decomposition of organic matter, loss of heat value and emission of peculiar smell gas caused by direct contact of high-temperature flue gas are effectively avoided, and difficulty in tail gas treatment and fuel supplement cost are effectively reduced. On the basis, an auxiliary sealing ring with a pre-leakage detection channel is additionally arranged at a connecting interface of a guide pipe and the drying disc, when micro-leakage of high-temperature steam occurs, leakage gas acts on a double-core pressure sensor through a gas guiding long groove and a slit groove, sensitive detection and early warning of early leakage are realized, heat value loss and peculiar smell generation caused by direct blowing of local steam to sludge are avoided, accurate basis is provided for sealing maintenance of the equipment, and long-term stable and efficient operation of the system is ensured.

Description

Technical Field

[0001] This invention relates to the field of sludge drying technology, and in particular to a sludge separation-type heat exchange drying and carbonization process. Background Technology

[0002] Sludge drying and carbonization technology is one of the important pathways to achieve sludge reduction, stabilization, and resource utilization. Currently, the most widely used process route is "direct flue gas heat exchange drying + carbonization". In this process, the high-temperature flue gas (temperature of about 900℃-1000℃) generated by the hot blast stove first enters the jacket of the carbonization furnace to heat the sludge carbonization process. After the temperature drops to 400℃-500℃, it then enters the rotary drum dryer to directly contact the sludge for heat exchange, thereby achieving the drying treatment of the sludge.

[0003] However, the aforementioned direct heat exchange drying method has two prominent problems in practical applications. First, the flue gas temperature in the drying section remains high, and direct contact with the sludge leads to partial pyrolysis and volatilization of organic matter in the sludge, resulting in a significant reduction in the sludge's calorific value. Upon entering the carbonization furnace, due to the insufficient calorific value of the sludge itself, the pyrolysis gas production decreases, requiring additional fuel to maintain the carbonization temperature, thus increasing operating costs. Second, the odorous gases produced by the decomposition of organic matter in the sludge at high temperatures mix with the flue gas and enter the tail gas treatment system. Deodorizing these gases is difficult and costly, easily leading to non-compliance with emission standards and secondary environmental pollution.

[0004] To address the issues of calorific value loss and odor pollution caused by direct flue gas drying, indirect drying methods using heat transfer media (such as steam or thermal oil) as a heat source can effectively avoid these drawbacks. However, existing indirect drying equipment is difficult to effectively couple with sludge carbonization processes. The main reason is that the flue gas temperature at the outlet of the carbonization furnace jacket has already dropped to 400℃-500℃, which falls within the range of medium-temperature waste heat. If a waste heat boiler is added for heat exchange and recovery, the equipment investment will be large, the thermal efficiency will be low, and the overall energy consumption of the system will be high.

[0005] Existing patented technologies have explored the utilization of thermal energy in sludge drying and carbonization systems. For example, Chinese utility model patent CN208667448U discloses a high-efficiency sludge carbonization treatment system that uses the heat generated by sludge incineration or carbonization to indirectly heat air to improve sludge drying efficiency. Chinese utility model patent CN207845466U discloses an energy-saving sludge treatment device that uses a heat pipe heat exchanger to recover heat generated during the drying and carbonization processes. While these solutions improve thermal energy utilization efficiency to some extent, none of them effectively solve the problem of heat transfer efficiency between the medium-temperature flue gas at the outlet of the carbonization furnace jacket and the indirect drying process. Summary of the Invention

[0006] The core of this invention lies in constructing a separate heat pipe heat exchange system to efficiently transfer the waste heat of the flue gas from the outlet of the carbonization furnace jacket to the sludge drying process, thereby achieving efficient cascade utilization of waste heat while maintaining the calorific value of the sludge and reducing odor emissions.

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] A sludge separation-type heat exchange drying and carbonization process includes the following steps: S1. After cooling the flue gas output from the carbonization furnace, it is introduced into the evaporator, so that the heat transfer medium in the evaporator is heated and evaporated to form steam. S2. Steam enters the cavity of the drying tray inside the dryer through the steam riser pipe, and indirectly exchanges heat with the sludge on the tray surface. The condensed droplets flow back to the evaporator through the condensate return pipe for reheating and evaporation, and the cycle continues. S3. The drying trays inside the dryer are arranged vertically, divided into large trays and small trays, and the large trays and small trays are arranged alternately. Under the action of the rotary rake, the material moves in a spiral from the center to the outside on the small tray, falls to the lower large tray, and then moves in a spiral from the outside to the center on the large tray. It falls through the central hole to the lower small tray, and so on, moving downwards in a spiral shape layer by layer. During the movement, the material exchanges heat with the tray surface and dries. After drying, the material is discharged from the bottom tray. S4. The carrier gas generated during the drying process is drawn out by the circulating fan, cooled by the heat exchanger, condensed and dehydrated by the condenser, and then heated by the heat exchanger before being returned to the dryer for reuse.

[0009] Furthermore, the evaporators are configured in two groups, both of which are vacuum heat exchange tubes. One group of evaporators contains deionized water, while the other group contains thermally conductive material. Multiple drying trays are divided into upper and lower groups. The evaporator containing deionized water corresponds to the lower drying tray group, and the evaporator containing thermally conductive material corresponds to the upper drying tray group. The inlet and outlet of each evaporator are connected to a steam riser pipe and a condensate return pipe, respectively. The steam riser pipe and the condensate return pipe are connected to multiple large and small trays in the corresponding drying tray group through guide pipes, forming a separate heat pipe heat exchange system.

[0010] Furthermore, the thermal conductivity is at an operating temperature of <370℃, and the saturated steam temperature of deionized water at a pressure of 0.6MPa is 158℃.

[0011] Furthermore, the evaporator and drying tray are evacuated to a vacuum state by a vacuum pump when the machine is started.

[0012] Furthermore, in step S1, the flue gas temperature output from the carbonization furnace is 400℃-500℃. After being cooled to below 370℃ by flue gas recirculation and mixing, it is then introduced into the evaporator.

[0013] Optionally, multiple guide tubes are sealed with sealing rings at their interfaces with the large or small disc. Each sealing ring includes a ring body, an outer protective sleeve fixedly connected to the middle of the outer end of the ring body, and a sealing gasket ring fixedly embedded in the inner wall of the opening on the side of the ring body away from the large or small disc. The ring body and the sealing gasket ring are provided with a pre-leakage detection channel. The radial end face of the ring body is attached to and welded to the outer wall of the large or small disc. The inner wall of the ring body is threadedly connected to the guide tube, and the sealing gasket ring is interference-fitted with the outer wall of the guide tube.

[0014] Furthermore, the pre-leakage detection channel includes a transversely opened air guide groove on the inner wall of the ring, a transversely opened sealing aid cavity in the sealing gasket ring, and a radially opened positive slit groove and a secondary slit groove in the ring. The positive slit groove is located between the air guide groove and the sealing aid cavity and communicates with both of them. An air guide hole is drilled on the sealing gasket ring, which connects the sealing aid cavity and the secondary slit groove. An isolation pressure sensing component is also provided between the positive slit groove and the secondary slit groove.

[0015] Furthermore, the ring body is provided with an installation hole located between the main slit groove and the secondary slit groove. The pressure-sensing isolation assembly includes a pressure sensor fixedly installed in the installation hole and two sealing diaphragms that are fixedly sealed at the opening of the installation hole. The sealing diaphragms are made of elastic high-temperature resistant material. Both ends of the pressure sensor are located inside the installation hole and face the main slit groove and the secondary slit groove respectively.

[0016] Compared with the prior art, the advantages of this invention are: (1) By introducing the high-temperature flue gas from the jacket outlet of the carbonization furnace into a separate heat pipe evaporator, heat is efficiently and isothermally transferred to the sludge in the drying tray through phase change heat transfer using two media, thermally conductive rubber and deionized water, in a vacuum environment, thus achieving indirect drying of the sludge without contact with the flue gas. This method effectively avoids the decomposition of organic matter and loss of calorific value of the sludge caused by direct contact with high-temperature flue gas, while reducing the emission of odorous gases, lowering the difficulty of tail gas treatment and fuel replenishment costs.

[0017] (2) Add a sealing ring with a pre-leak detection channel at the connection interface between the guide pipe and the drying tray. When a micro-leak occurs in the high-temperature steam, the leaked gas acts on the dual-core pressure sensor through the gas guide groove and the slit groove, realizing sensitive detection and early warning of early leakage, avoiding local steam blowing directly into the sludge, causing heat loss and odor generation, providing accurate basis for equipment sealing maintenance, and ensuring long-term stable operation of the system. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the principle of the present invention; Figure 2 This is a schematic diagram showing the arrangement of the drying trays inside the dryer of the present invention; Figure 3 for Figure 2 A schematic diagram at point A in the middle; Figure 4 This is a top view of the drying tray assembly of the present invention; Figure 5 This is a cross-sectional schematic diagram of the sealing ring of the present invention; Figure 6 for Figure 5 A schematic diagram at point B in the middle; Figure 7 This is a cross-sectional schematic diagram of the sealing ring portion of the present invention in the event of steam leakage.

[0019] Explanation of the labels in the diagram: 1. Small plate, 2. Large plate, 31. Steam riser pipe, 32. Condensate return pipe, 4. Guide pipe, 5. Sealing ring, 51. Outer protective sleeve, 52. Ring body, 53. Sealing gasket ring, 501. Air guide groove, 502. Sealing cavity, 503. Positive slit groove, 504. Secondary slit groove, 505. Air guide hole, 6. Pressure sensor, 601. Sealing diaphragm. Detailed Implementation

[0020] The technical solutions will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0021] First implementation method: like Figure 1 A sludge separation-type heat exchange drying and carbonization process includes the following steps: S1. The flue gas output from the carbonization furnace is cooled and then introduced into the evaporator, so that the heat transfer medium in the evaporator is heated and evaporated to form steam. The temperature of the flue gas output from the carbonization furnace is 400℃-500℃. After the flue gas is refluxed and mixed, it is cooled to below 370℃ before being introduced into the evaporator. S2. Steam enters the cavity of the drying tray inside the dryer through the steam riser pipe, and indirectly exchanges heat with the sludge on the tray surface. The condensed droplets flow back to the evaporator through the condensate return pipe for reheating and evaporation, and the cycle continues. S3. The drying trays inside the dryer are arranged vertically, consisting of a large tray 2 and a small tray 1, with the large tray 2 and small tray 1 arranged alternately. Under the action of the rotary rake, the material moves in a spiral from the center to the outside on the small tray 1, falls to the lower large tray 2, and then moves in a spiral from the outside to the center on the large tray 2, falling through the central hole to the lower small tray 1. This spiral movement continues layer by layer downwards, exchanging heat with the tray surface during the movement and drying. After drying, the material is discharged from the bottom tray. S4. The carrier gas generated during the drying process is drawn out by the circulating fan, cooled by the heat exchanger, condensed and dehydrated by the condenser, and then heated by the heat exchanger before being returned to the dryer for reuse.

[0022] Two sets of evaporators are configured, both of which are vacuum heat exchange tubes. One set of evaporators contains deionized water, while the other set contains thermally conductive evaporators. Multiple drying trays are divided into upper and lower groups. The evaporators containing deionized water correspond to the lower drying tray group, and the evaporators containing thermally conductive evaporators correspond to the upper drying tray group. The upper drying tray group is located on the material inlet side of the dryer. In this area, the sludge has just entered the dryer and has a high moisture content, requiring a higher drying temperature. Therefore, it is equipped with thermally conductive evaporators with a higher operating temperature. The lower drying tray group is located on the material outlet side of the dryer. In this area, the sludge has already undergone preheating and partial drying in the upper section, resulting in a significantly reduced moisture content and a lower requirement for drying temperature. Therefore, it is equipped with deionized water evaporators with a moderate operating temperature.

[0023] In addition, the inlet and outlet of each of the two evaporators are respectively connected to a steam riser pipe 31 and a condenser return pipe 32. The steam riser pipe 31 and the condenser return pipe 32 are connected to multiple large plates 2 and small plates 1 in the corresponding drying tray group through guide pipes 4 to form a separate heat pipe heat exchange system.

[0024] The operating temperature of the thermally conductive material is <370℃, while the saturated steam temperature of deionized water at 0.6MPa pressure is 158℃ and its boiling point at atmospheric pressure is 100℃. The boiling point of the thermally conductive material is 257℃, and the boiling point of deionized water at atmospheric pressure is 100℃. Since the flue gas temperature output from the carbonization furnace is as high as 400℃-500℃, and after cooling to below 370℃, it belongs to medium-high temperature waste heat. If deionized water operates at its boiling point of 100℃ at atmospheric pressure, its heat transfer temperature difference is large, and its heat utilization efficiency is low, making it impossible to fully recover the heat in this temperature range. By pressurizing the deionized water to 0.6MPa, its saturated steam temperature is increased to 158℃, thus forming a more suitable heat exchange temperature difference with the high-temperature flue gas, effectively improving heat recovery efficiency. Therefore, a thermally conductive evaporator is used for heat absorption in the high-temperature flue gas section, while a pressurized deionized water evaporator is used for heat absorption in the low-temperature flue gas section. This is to coordinate two sets of evaporators to meet the different drying temperature requirements of different areas within the dryer. The sludge in the upper drying trays has just entered the dryer and has a higher moisture content, requiring a higher drying temperature, so a thermally conductive evaporator is added accordingly. The sludge in the lower drying trays has already undergone drying in the upper section, and its moisture content has been significantly reduced, so the required drying temperature is lower, and a deionized water evaporator is used accordingly.

[0025] When the evaporator and drying trays are started up, they are evacuated to a vacuum state by a vacuum pump. The vacuum pump is connected to the condensate return pipes 32 on the two sets of drying trays through two gas guide pipes. Each gas guide pipe is equipped with a valve, which is normally closed and will only be opened when the vacuum pump needs to evacuate. Therefore, it will not affect the normal condensate return function of the condensate return pipes 32. This makes the evaporator and the drying trays of the dryer a set of separate heat pipe heat exchange systems. When the temperature of the high-temperature flue gas from the carbonization furnace jacket is controlled to be less than 370°C, it enters the evaporator. Because the evaporator is in a vacuum environment, the heat transfer medium is heated and quickly evaporates into steam. It enters the cavity of the drying trays of the dryer through the steam riser pipe 31 and the corresponding guide pipe 4. Heat exchange occurs between the drying tray surface and the sludge. After the steam releases heat, it condenses into droplets and collects on the bottom surface of the drying tray under the action of gravity. Then it flows back into the evaporator through the condensate return pipe 32 for reheating and evaporation. This cycle of heat absorption and release continues.

[0026] Because the vacuum heat exchange system has good isothermal properties, the temperature difference between the evaporator and the drying tray can be controlled within a small range, typically 5-15℃, after system startup. This means the evaporation temperature of the medium in the evaporator is essentially the same as the condensation temperature in the drying tray. This is because the split heat pipe relies on the phase change of the medium for heat transfer. The saturation temperature difference between the evaporator in the evaporation section and the drying tray in the condensation section is mainly determined by the steam flow resistance and the static pressure difference of the liquid column. Under conditions of reasonable system piping layout, sufficient vacuum extraction, and maintenance of vacuum, this temperature difference can be controlled within a reasonable range. Therefore, the heat from the flue gas can be isothermally and efficiently transferred to the material being dried with minimal temperature loss, achieving efficient drying of the material.

[0027] Through the aforementioned separate heat exchange drying process, the high-temperature flue gas heat from the carbonization furnace jacket is efficiently transferred to the dryer to dry the sludge. The sludge dries on the trays, and compared to direct heat exchange with hot air, the temperature is lower, and the calorific value of the sludge is preserved to the maximum extent during the drying process. The pyrolysis gas volume of the sludge carbonization is large, and the amount of fuel added is reduced, thereby reducing the cost of sludge treatment. At the same time, the odorous gases generated during the sludge drying process run inside the dryer through the circulating dehydration heat exchange process, and are not likely to be emitted to the outside and cause odor pollution. Moreover, compared to the direct contact heat exchange between the flue gas and the sludge, there is no odor in the flue gas, so there is no need for further treatment of the odor. It can meet the emission standards after only conventional treatment.

[0028] Second implementation method: The core of the first implementation method is to construct a separate heat pipe heat exchange system so that the high-temperature flue gas used for drying does not come into direct contact with the sludge, thereby reducing the heat loss and odor pollution during the sludge drying process. However, the design of the separate heat pipe heat exchange system has multiple pipe interfaces for gas conduction inside the dryer. Under high-temperature conditions, these interfaces are prone to wear and leakage. If this problem is not solved in time, it will cause local steam to continuously blow directly onto the sludge, causing heat loss in that part of the sludge. In severe cases, it may even lead to the degeneration of this solution into a drying method that directly exchanges heat with the sludge.

[0029] like Figures 2-4 Based on the above problems, this embodiment adds a sealing ring 5 at the connection interface between the guide tube 4 and the large plate 2 or the small plate 1, on the one hand to improve the sealing performance at the interface, and on the other hand to detect potential leakage of high-temperature gas in advance for early maintenance. The specific details of the sealing ring 5 are as follows: like Figures 5-6 Multiple guide tubes 4 are sealed with sealing rings 5 ​​at their interfaces with the large plate 2 or the small plate 1. Each sealing ring 5 includes a ring body 52, an outer protective sleeve 51 fixedly connected to the middle of the outer end of the ring body 52, and a sealing gasket ring 53 fixedly embedded in the inner wall of the opening on the side of the ring body 52 away from the large plate 2 or the small plate 1. A pre-leakage detection channel is jointly provided inside the ring body 52 and the sealing gasket ring 53. The radial end face of the ring body 52 is bonded and welded to the outer wall of the large plate 2 or the small plate 1, effectively ensuring the stability of the connection between the sealing ring 5 and the small plate 1 or the large plate 2. Welding also effectively prevents air leakage at the connection between the radial surface of the ring body 52 and the small plate 1 or the large plate 2. When leakage occurs, the leaked air is forced into the pre-leakage detection channel, thereby achieving centralized detection. The leaked steam can be detected in its early stages. The inner wall of the ring 52 is threaded to the guide pipe 4, which facilitates the disassembly and assembly of the guide pipe 4 and the sealing ring 5, making maintenance easier. The sealing ring 53 is interference-fitted with the outer wall of the guide pipe 4, forming a final sealing barrier between the guide pipe 4 and the sealing ring 5. When a leak occurs, the sealing ring 53 can intercept the early leaked gas, forcing the gas to accumulate and diffuse into the pre-leak detection channel, further accelerating the detection of early leaks. Compared with the existing technology, which only detects leaks after obvious abnormalities appear, this technology significantly improves the detection sensitivity of steam leaks, thereby effectively avoiding excessive calorific value loss or odor generation during sludge drying.

[0030] The pre-leakage detection channel includes a transversely formed air guide groove 501 on the inner wall of the ring 52, a transversely formed sealing cavity 502 within the sealing gasket ring 53, and a radially formed positive slit groove 503 and a secondary slit groove 504 within the ring 52. The positive slit groove 503 is located between the air guide groove 501 and the sealing cavity 502, and communicates with both. An air guide hole 505 is formed on the sealing gasket ring 53, connecting the sealing cavity 502 and the secondary slit groove 504. An isolation pressure-sensing component is also provided between the positive slit groove 503 and the secondary slit groove 504. Figure 7 When a leak occurs, the leaked gas seeps into the gas guide groove 501 and spreads rapidly along the gas guide groove 501 to the positive slit groove 503, and then diffuses into the sealing chamber 502 and the secondary slit groove 504. On the one hand, the gas entering the sealing chamber 502 will exert a squeezing force on the sealing ring 53, making it more tightly connected with the guide tube 4 and the ring body 52, so as to strengthen the sealing performance of the last sealing line. On the other hand, the gas entering the secondary slit groove 504 and the positive slit groove 503 will work together on the isolation pressure sensing component, causing it to generate obvious pressure data. As the leakage time accumulates, the pressure data becomes larger and larger. Based on the data changes, the staff can judge that there is an early leakage risk and then maintain it in time to effectively avoid excessive loss of heat value or generation of odor during sludge drying.

[0031] The ring 52 also has an installation hole inside, located between the main slit groove 503 and the secondary slit groove 504. The pressure-sensing isolation assembly includes a pressure sensor 6 fixedly installed in the installation hole and two sealing diaphragms 601 respectively fixed to seal the opening of the installation hole. The pressure sensor 6 is a dual-core pressure sensor that can independently collect pressure data from both sides. The sealing diaphragms 601 are made of elastic high-temperature resistant material. Both ends of the pressure sensor 6 are located inside the installation hole and face the main slit groove 503 and the secondary slit groove 504 respectively. When leaked steam enters the main slit groove 503 and the secondary slit groove 504, it will exert a squeezing force on the sealing diaphragms 601, thereby causing the two ends of the pressure sensor 6 to be stressed, thus generating pressure data. As the amount of leaked steam increases, the data will also increase significantly, thereby realizing the detection of early steam leakage.

[0032] The above description is merely a preferred embodiment of the present invention; it encompasses all the protection scope of the present invention. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solutions and improved concepts of the present invention, should be covered within the protection scope of the present invention.

Claims

1. A sludge separation-type heat exchange drying and carbonization process, characterized in that: Includes the following steps: S1. After cooling the flue gas output from the carbonization furnace, it is introduced into the evaporator, so that the heat transfer medium in the evaporator is heated and evaporated to form steam. S2. The steam enters the cavity of the drying tray inside the dryer through the steam riser pipe, and indirectly exchanges heat with the sludge on the tray surface. The condensed droplets flow back to the evaporator through the condensate return pipe for reheating and evaporation, and the cycle continues. S3. The drying trays inside the dryer are arranged vertically, divided into a large tray (2) and a small tray (1), and the large tray (2) and the small tray (1) are arranged alternately. Under the action of the rotary rake, the material moves in a spiral from the middle to the outside on the small tray (1), falls to the lower large tray (2), and then moves in a spiral from the outside to the middle on the large tray (2), falls through the central hole to the lower small tray (1), and so on, moving downwards in a spiral shape layer by layer. During the movement, the material exchanges heat with the tray surface and dries. After drying, the material is discharged from the bottom tray surface. S4. The carrier gas generated during the drying process is drawn out by the circulating fan, cooled by the heat exchanger, condensed and dehydrated by the condenser, and then heated by the heat exchanger before being returned to the dryer for reuse.

2. The sludge separation heat exchange drying and carbonization process according to claim 1, characterized in that: The evaporator is set in two groups, and both groups of evaporators are vacuum heat exchange tubes. One group of evaporators is filled with deionized water, and the other group of evaporators is filled with thermally conductive material. Multiple drying trays are divided into upper and lower groups. The evaporator filled with deionized water corresponds to the lower drying tray group, and the evaporator filled with thermally conductive material corresponds to the upper drying tray group. The inlet and outlet of each of the two evaporators are respectively connected to a steam riser pipe (31) and a condensation return pipe (32). The steam riser pipe (31) and the condensation return pipe (32) are connected to multiple large trays (2) and small trays (1) in the corresponding drying tray group through guide pipes (4) to form a separate heat pipe heat exchange system.

3. The sludge separation heat exchange drying and carbonization process according to claim 1, characterized in that: The operating temperature of the thermally conductive material is <370℃, and the saturated steam temperature of the deionized water at a pressure of 0.6MPa is 158℃.

4. The sludge separation heat exchange drying and carbonization process according to claim 1, characterized in that: The evaporator and drying tray are evacuated to a vacuum state by a vacuum pump when the machine is started.

5. The sludge separation heat exchange drying and carbonization process according to claim 1, characterized in that: In step S1, the flue gas temperature output from the carbonization furnace is 400℃-500℃. After being cooled to below 370℃ by flue gas recirculation and mixing, it is then introduced into the evaporator.

6. The sludge separation heat exchange drying and carbonization process according to claim 2, characterized in that: Each of the multiple guide tubes (4) is sealed with a sealing ring (5) at the interface with the large plate (2) or the small plate (1). The sealing ring (5) includes a ring body (52), an outer protective sleeve (51) fixedly connected to the middle of the outer end of the ring body (52), and a sealing gasket ring (53) fixedly embedded in the inner wall of the opening on the side of the ring body (52) away from the large plate (2) or the small plate (1). The ring body (52) and the sealing gasket ring (53) are provided with a pre-leakage detection channel. The radial end face of the ring body (52) is attached to and welded to the outer wall of the large plate or the small plate. The inner wall of the ring body (52) is threadedly connected to the guide tube (4). The sealing gasket ring (53) is interference-fitted with the outer wall of the guide tube (4).

7. The sludge separation heat exchange drying and carbonization process according to claim 6, characterized in that: The pre-leakage detection channel includes a transversely opened air guide groove (501) on the inner wall of the ring (52), a transversely opened sealing cavity (502) in the sealing gasket ring (53), and a radially opened positive slit groove (503) and a secondary slit groove (504) in the ring (52). The positive slit groove (503) is located between the air guide groove (501) and the sealing cavity (502) and communicates with both. An air guide hole (505) is drilled on the sealing gasket ring (53). The air guide hole (505) communicates with the sealing cavity (502) and the secondary slit groove (504). An isolation pressure sensing component is also provided between the positive slit groove (503) and the secondary slit groove (504).

8. The sludge separation heat exchange drying and carbonization process according to claim 7, characterized in that: The ring (52) is also provided with an installation hole, which is located between the main slit groove (503) and the secondary slit groove (504). The isolation pressure sensing assembly includes a pressure sensor (6) fixedly installed in the installation hole and two sealing diaphragms (601) that are respectively fixed and sealed at the opening of the installation hole. The sealing diaphragms (601) are made of elastic high temperature resistant material. Both ends of the pressure sensor (6) are located inside the installation hole and face the main slit groove (503) and the secondary slit groove (504) respectively.

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