A new type of partition wall sludge drying machine

Abstract

This application provides a novel indirect-contact sludge dryer, which allows for system construction with low initial investment, achieves excellent sludge drying results, and eliminates the need for additional waste gas treatment equipment, resulting in low overall operating costs. Based on a shell assembly, a flue gas circulation assembly, and a stirring shaft assembly, it forms an indirect-contact heat exchange structure. The high-temperature flue gas used does not directly contact the sludge, serving only as a heat provider. The sludge drying process utilizes only the heat from the flue gas. The entire flue gas circulation system is a closed, independent channel. After drying, the flue gas composition remains unchanged, eliminating the need for an additional flue gas treatment system; it can be directly connected back to the original flue gas treatment system.

Description

Technical Field

[0001] This invention relates to the field of sludge drying technology, specifically a novel partitioned sludge drying machine. Background Technology

[0002] The principles and requirements for sludge treatment are to achieve "reduction, stabilization, harmlessness, and resource recovery." Sludge drying is the prerequisite and key to sludge treatment and disposal technology.

[0003] Sludge drying relies on heat, which is typically generated by the combustion of energy sources. Currently, heat utilization falls into two main categories:

[0004] Direct heating: High-temperature flue gas is directly introduced into the dryer, and heat exchange occurs through contact and convection between the high-temperature flue gas and the wet material. This method is characterized by high heat utilization efficiency, but it can lead to exhaust gas emission problems because pollutants are generated during the drying process of the sludge.

[0005] Indirect heating: Heat is transferred to a heat transfer medium, such as thermal oil, steam, or air, through a heat exchanger. The medium circulates in a closed loop and does not come into contact with the material being dried. For example, in an indirect drying process using hot oil as the heat transfer medium, the heat source does not contact the sludge; heat exchange occurs through the thermal oil, and the corresponding equipment is a thermal oil boiler or a steam boiler.

[0006] For example, patent application number CN201610249891.3 involves two drying methods. However, when using the direct drying method, due to the direct contact between flue gas and sludge, the amount of exhaust gas and humid heat generated is large; at the same time, the odor / VOC in the exhaust gas is difficult to treat and the treatment cost is high. When using the indirect drying method, a heat source is needed to generate steam, and then the steam is used to indirectly dry the sludge. The disadvantages are that the energy needs to be converted twice, resulting in reduced efficiency; this drying equipment, because it has to withstand steam pressure, is a pressure-bearing component, requiring high equipment standards and a complex system; the sludge contains sand and gravel, and there is a risk of wear and leakage during long-term operation, thus resulting in large equipment investment and high operating costs. Summary of the Invention

[0007] To address the high operating costs of existing sludge drying systems, this invention provides a novel partitioned sludge dryer that allows for system construction with minimal upfront investment, delivers excellent sludge drying results, eliminates the need for additional waste gas treatment equipment, and minimizes overall operating costs.

[0008] The technical solution of the present invention is as follows: a novel indirect-contact sludge dryer, comprising: a shell assembly, a flue gas circulation assembly, and a stirring shaft assembly; the shell assembly comprises: a hollow shell, with a feed inlet at the upper part of one end of the shell and a discharge outlet at the lower part of the other end, the feed inlet and the discharge outlet communicating with the inner cavity of the shell; heat-absorbing fins are arranged on the outside of the shell;

[0009] Its features are:

[0010] The flue gas recirculation assembly includes: a tubular flue gas recirculation shell and a flue gas hood, wherein the flue gas recirculation shell is welded to the heat-absorbing fins; the flue gas hoods are respectively disposed above and below the flue gas recirculation shell along the axial direction of the shell, and the upper and lower flue gas hoods are staggered; the inner cavities of the flue gas recirculation shell and the flue gas hood are interconnected, and a serpentine circulation cavity is formed between them and the shell; a flue gas inlet is provided at the lower part of one end of the flue gas recirculation shell, and a flue gas outlet is provided at the upper part of the other end;

[0011] The stirring shaft assembly includes a stirring shaft and a rotary sealing device.

[0012] The stirring shaft includes: a hollow tube, stirring blades, a stirring arc plate, and an inner spiral blade; the hollow tube is arranged in the inner cavity of the shell along the axial direction of the shell; the stirring blades are arranged on the outer wall of the hollow tube, and the stirring blades and the hollow tube are inclined at a preset angle in the radial direction and arranged in a spiral structure along the axial direction; the stirring arc plate is welded to one side of the stirring blade in the spiral direction, and the stirring arc plate is eccentrically arranged with the blade; the inner spiral blades are arranged in the hollow tube along the axial direction, and the inner spiral blades and the inner wall of the hollow tube together form a spiral flue gas channel;

[0013] The hollow tube has a flue gas inlet and a flue gas outlet at its two ends.

[0014] Its further features are:

[0015] The stirring shaft includes two shafts, which are simultaneously disposed in the inner cavity of the housing. The stirring blades on the two stirring shafts are staggered on the outer wall of the hollow tube, and the two stirring shafts rotate in opposite directions.

[0016] The rotary sealing device includes a sealing seat and a sealing cover. The sealing seat is fixed to the stirring shaft with bolts and rotates together with the stirring shaft. The sealing cover is connected and fixed to the flue gas inlet and outlet pipes. The sealing seat and the sealing cover are non-contact labyrinth structures, and the gap between the two parts is sealed with graphite packing.

[0017] The spiral blades inside the tube are fixed at both ends along the axial direction of the hollow tube inside the cavity, and the height of the spiral blades inside the tube is adapted to the diameter of the hollow tube.

[0018] It also includes: a power system, which comprises: a frequency-modulated reducer and a frequency-modulated induced draft fan;

[0019] The stirring shaft is driven to rotate by the frequency-controlled reducer; the high-temperature flue gas entering the flue gas circulation assembly and the stirring shaft cavity is driven by the frequency-controlled induced draft fan.

[0020] It also includes: a carrier gas inlet and a carrier gas outlet disposed on the housing and communicating with the inner cavity of the housing, wherein the carrier gas inlet is disposed at one end of the feed port and the carrier gas outlet is disposed at one end of the discharge port and disposed on the upper part of the housing;

[0021] The power system also includes: a frequency-modulated induced draft fan for carrier gas, which drives the carrier gas entering the carrier gas inlet;

[0022] It also includes a control system, which uses the frequency-modulated motor to control the rotation speed of the stirring shaft, thereby controlling the moisture content and output of the dried sludge; controls the flow speed of the flue gas in the flue gas circulation shell and the stirring shaft by controlling the frequency of the frequency-modulated induced draft fan, thereby controlling the heat exchange rate between the flue gas and the sludge; and regulates the temperature and humidity inside the shell by controlling the flow speed of the carrier gas using the frequency-modulated motor.

[0023] It also includes: remote pressure gauges and remote thermocouples. A set of remote pressure gauges and remote thermocouples are respectively installed at the flue gas inlet, the flue gas outlet and the carrier gas outlet to adapt to different operating conditions of the equipment. By controlling the frequency of the frequency-controlled induced draft fan and the frequency-controlled induced draft fan for the carrier gas, the pressure and temperature at the flue gas outlet and the carrier gas outlet can be controlled.

[0024] This application provides a novel indirect-contact sludge dryer, which is based on a shell assembly, a flue gas circulation assembly, and a stirring shaft assembly, forming an indirect-contact heat exchange structure. The high-temperature flue gas used does not directly contact the sludge, but only serves as a heat provider. Only the heat from the flue gas is utilized during the sludge drying process. The entire flue gas circulation system is a closed, independent channel. After drying, the flue gas composition remains unchanged, eliminating the need for an additional flue gas treatment system; it can be directly connected back to the original flue gas treatment system. In this application, sludge enters the sludge channel within the shell cavity, while flue gas simultaneously enters two channels in the flue gas circulation assembly and the stirring shaft assembly. The sludge is stirred and transported by the stirring shaft within the shell cavity. Eccentric stirring arc plates on the blades ensure thorough stirring of the sludge. During stirring and transport, the flue gas in the two flue gas channels heats the sludge simultaneously from both inside and outside, greatly improving the sludge drying effect. The high-temperature flue gas heating channel includes two channels located in the flue gas circulation assembly and the stirring shaft assembly. The flue gas circulation assembly, through a flue gas hood staggered vertically within the flue gas circulation shell, forms a serpentine flue gas circulation around the shell. The system utilizes a serpentine flue gas circulation channel to allow high-temperature flue gas to flow. Heat-absorbing fins welded to the shell increase the shell's heat-receiving area, maximizing heat absorption and improving heat exchange efficiency between the flue gas and the shell. Furthermore, a rotary sealing device directs the flue gas into the stirring shaft's inner cavity, and a damping spiral creates a spiral flue within the shaft, further enhancing heat exchange efficiency between the flue gas and the stirring shaft. These two flue gas channels significantly increase the evaporation rate of water from the sludge. This technical solution maximizes the utilization of the equipment's heat-receiving area within a fixed equipment volume, improving sludge drying efficiency and quantity. The dryer in this application has no pressure-bearing structure; all components are purely mechanical, ensuring safe operation and requiring less initial investment and lower construction costs. Simultaneously, the dryer's simple overall structure and high thermal efficiency allow for direct access to high-temperature flue gas without secondary energy conversion, reducing intermediate steps and saving energy costs associated with traditional sludge drying methods. It also achieves efficient utilization of waste heat from the flue gas. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of a sludge dryer;

[0026] Figure 2 This is a schematic diagram of the shell assembly structure;

[0027] Figure 3 for Figure 1 A schematic diagram of the structure in cross-section along the AA direction;

[0028] Figure 4 This is a schematic diagram of the stirring shaft assembly structure;

[0029] Figure 5 This is a schematic diagram of the blade structure;

[0030] Figure 6 for Figure 4 A schematic diagram of the cross-section along the CC direction;

[0031] Figure 7 for Figure 1 Top view of the structure;

[0032] Figure 8 for Figure 7 A schematic diagram of the structure in cross-section along the BB direction;

[0033] Figure 9 This is a schematic diagram of the structure of the helical blade inside the tube. Detailed Implementation

[0034] like Figures 1-9 As shown, the present invention includes a novel partitioned sludge dryer, which includes: a shell assembly 1, a flue gas circulation assembly 2, a stirring shaft assembly 3, and a power system.

[0035] The shell assembly 1 includes: a hollow shell 1-1, with end face flanges 1-3 at both ends of the shell; a wet sludge inlet 1-4 is provided at the upper part of one end of the shell 1-1, and a carrier gas inlet 1-5 is provided on the same side end face flange; a dry sludge outlet 1-6 is provided at the lower part of the other end, and a carrier gas outlet 1-7 and an observation port 1-8 are provided at the upper part; the inlet 1-4 and the outlet 1-6 are connected to the inner cavity of the shell 1-1; heat-absorbing fins 1-2 are arranged on the outside of the shell 1-1. The wet sludge enters the inner cavity of the shell 1-1 through the inlet 1-4, is stirred and conveyed by the stirring shaft 3-1, and is discharged from the outlet 1-6 after drying.

[0036] The carrier gas inlet 1-5 and the carrier gas outlet 1-7 are also connected to the inner cavity of the shell 1-1. The carrier gas in this application is based on air. During the drying process of wet sludge, the water vapor and other waste gases generated are carried away from the inner cavity of the shell 1-1 by the carrier gas and sent to the subsequent treatment process.

[0037] The flue gas recirculation assembly 2 includes a tubular flue gas recirculation shell 2-1 and a flue gas hood 2-4. The flue gas recirculation shell 2-1 is welded to the heat-absorbing fins 1-2. The flue gas hoods 2-4 are respectively arranged above and below the flue gas recirculation shell 2-1 along the axial direction of the shell 1-1, and the upper and lower flue gas hoods 2-4 are staggered. The inner cavities of the flue gas recirculation shell 2-1 and the flue gas hoods 2-4 are interconnected, forming a serpentine circulating sealed space with the outer surface of the shell 1-1. A flue gas inlet 2-2 is provided at the lower part of one end of the flue gas recirculation shell 2-1, and a flue gas outlet 2-3 is provided at the upper part of the other end. The flue gas recirculation assembly 2 utilizes the staggered arrangement of the upper and lower flue gas hoods 2-4 to make the flue gas circulate in a serpentine manner around the outside of the shell 1-1 in the sealed space, forming a continuous heating of the shell 1-1, causing the sludge moisture inside the shell to evaporate and separate, thereby achieving the purpose of drying the sludge.

[0038] Stirring shaft assembly 3: stirring shaft 3-1 and rotary sealing device 3-2.

[0039] The stirring shaft 3-1 includes: a hollow tube 3-1-1, stirring blades 3-1-2, a stirring arc plate 3-1-3, and an inner spiral blade 3-1-4; the hollow tube 3-1-1 is arranged along the axial direction of the shell 1-1 in the inner cavity of the shell 1-1; the two ends of the inner cavity of the hollow tube 3-1-1 are respectively provided with a stirring shaft flue gas inlet 3-1-6 and a stirring shaft flue gas outlet 3-1-5. In this embodiment, there are two stirring shafts 3-1, which are arranged in the inner cavity of the shell 1-1 to increase the amount of sludge drying, and the stirring blades 3-1-2 on the two stirring shafts 3-1 are spirally arranged on the outer wall of the hollow tube 3-1-1 and interlaced with each other to ensure that the sludge between them can be fully stirred; the two stirring shafts 3-1 rotate in opposite directions by gear transmission.

[0040] Two counter-rotating stirring shafts are installed in the inner cavity of the shell, which not only improves the sludge conveying, but also ensures that the sludge between the two stirring shafts is fully stirred by the staggered arrangement of the stirring blades between them. Although the sludge between the two stirring shafts is baked to a lower degree by the high-temperature flue gas in the flue gas circulation component, it can be baked by the high-temperature flue gas in the inner cavity of the two stirring shafts at the same time, ensuring that there are no dead spots for drying in the inner cavity of the shell.

[0041] A stirring blade 3-1-2 is installed on the outer wall of the hollow tube 3-1-1. The stirring blade 3-1-2 is inclined to the hollow tube 3-1-1 at an angle of 5° to 20° in the radial direction and arranged in a spiral structure along the axial direction. The pitch between adjacent blades 3-1-2 is set between 100mm and 150mm. A stirring arc plate 3-1-3 is welded to one side of the stirring blade 3-1-2 in the spiral direction. Figure 5 As shown, the stirring arc plate 3-1-3 and the blades are eccentrically arranged. When the stirring shaft 3-1 rotates, the stirring blades 3-1-2 and the stirring arc plate 3-1-3 work together to stir the sludge in the shell 1-1, ensuring that the sludge is thoroughly stirred and heated evenly during the stirring process. The sludge is fully dried by evaporating the moisture in the sludge using the flue gas temperature. At the same time, the spiral structure of the stirring blades 3-1-2 pushes the sludge towards the discharge port.

[0042] like Figure 4 and Figure 6 As shown, an internal helical blade 3-1-4 is arranged axially inside the hollow tube 3-1-1. The internal helical blade 3-1-4 and the inner wall of the hollow tube 3-1-1 together form a helical flue gas channel; as shown... Figure 9As shown, the spiral blades 3-1-4 inside the tube are arranged axially along the hollow tube 3-1-1 via hollow rods 3-1-7. Both ends of the hollow rods 3-1-7 are fixed to the inner cavity of the hollow tube 3-1-1 via claw-shaped fixing plates 3-1-8. The height of the spiral blades 3-1-4 inside the tube is adapted to the diameter of the hollow tube 3-1-1. High-temperature flue gas enters from the main flue gas inlet 1-1-1, and then enters the flue gas circulation assembly 2 from the flue gas inlet 2-2, and enters the inner cavity of the hollow tube 3-1-1 from the flue gas inlet 3-1-6 of the stirring shaft. After entering the inner cavity of the hollow tube 3-1-1, the high-temperature flue gas enters the spiral flue gas channel via the spiral blades 3-1-4, reducing the flue gas flow velocity and increasing the heat-receiving area of ​​the inner surface of the stirring shaft 3-1, thereby improving the heat utilization rate of the flue gas.

[0043] Rotary sealing devices 3-2 are installed at both ends of the stirring shaft 3-1 to connect the stirring shaft 3-1 to the flue gas inlet and outlet. The rotary sealing device 3-2 includes a sealing seat 3-2-1 and a sealing cover 3-2-2. The sealing seat 3-2-1 is fixed to the stirring shaft 3-1 with bolts and rotates together with the stirring shaft 3-1. The sealing cover 3-2-2 is connected and fixed to the flue gas inlet and outlet pipes. The sealing seat 3-2-1 and the sealing cover 3-2-2 are in the form of a labyrinth non-contact structure. Graphite packing 3-2-3 is used to fill the gap between the two parts in the labyrinth to achieve the purpose of sealing. The specific implementation is based on the existing structure.

[0044] The power system includes: frequency-modulated reducer 4-1, frequency-modulated induced draft fan 4-3, and frequency-modulated induced draft fan for carrier gas.

[0045] The stirring shaft 3-1 is driven to rotate by the frequency reducer 4-1; the frequency reducer 4-1 is connected to the coupling 4-2 to drive the stirring shaft 3-1.

[0046] The high-temperature flue gas entering the inner cavity of the flue gas recirculation assembly 2 and the stirring shaft 3-1 is driven by the frequency-controlled induced draft fan 4-3; the carrier gas entering the carrier gas inlet 1-5 is driven by the frequency-controlled induced draft fan. The flue gas recirculation system adopts a negative pressure frequency-controlled induced draft fan. Under the rated conditions of inlet flue gas pressure and temperature, the pressure of the outlet flue gas is adjusted by adjusting the frequency of the induced draft fan to control the heating temperature of the equipment.

[0047] The technical solution presented in this application is applicable to high-temperature flue gas from diverse sources, including flue gas from various incinerators / kilns, and hot air from various chemical waste gases. The sludge drying equipment is heat-resistant and can accept various gases below 1000℃. Because the flue gas and sludge do not directly contact each other during the drying process, the composition of the flue gas remains unchanged. After heat exchange, the high-temperature flue gas can be directly returned to its original flue gas treatment system for purification, eliminating the need for an additional flue gas purification system for the sludge dryer and reducing the overall investment cost of this technical solution.

[0048] In practical applications, the control system controls the operation of each component, and the control system adopts a digital display control module based on existing technologies such as PLC.

[0049] The control system uses a frequency-modulated motor to control the rotation speed of the stirring shaft 3-1, thereby controlling the movement speed of the sludge towards the outlet, and thus controlling the moisture content and output of the dried sludge; ensuring that the moisture content of the output dried sludge is adjustable, and the moisture content of the dried sludge can be controlled within the range of 10-50% according to specific needs.

[0050] By controlling the frequency of the frequency-controlled induced draft fan 4-3, the flow speed of the high-temperature flue gas in the flue gas circulation shell 2-1 and the stirring shaft 3-1 is controlled, thereby controlling the heat exchange rate between the high-temperature flue gas and the sludge; the temperature inside the shell 1-1 is adjusted by using a frequency-controlled motor to control the flow speed of the carrier gas.

[0051] The control system also includes a remote pressure gauge 4-5-1 and a remote thermocouple 4-5-2. A set of remote pressure gauges 4-5-1 and remote thermocouples 4-5-2 are installed at the flue gas inlet 2-2, the flue gas outlet 2-3, and the carrier gas outlet 1-7, respectively, to adapt to different operating conditions of the equipment. By controlling the frequency of the frequency-controlled induced draft fan 4-3 and the frequency-controlled induced draft fan for the carrier gas, the pressure and temperature at the flue gas outlet 2-3 and the carrier gas outlet 1-7 are controlled.

[0052] By controlling the frequencies of the frequency-modulated reducer 4-1, the frequency-modulated induced draft fan 4-3, and the frequency-modulated induced draft fan for the carrier air, the sludge drying equipment can be used to dry various wet sludges with a moisture content of 30-90%, and has strong adaptability.

[0053] Using the technical solution of this invention, the waste heat of flue gas at 200-1000℃ is used for efficient thermal drying of wet sludge with a moisture content of 30-90%. During the drying process, the high-temperature flue gas does not directly contact the wet sludge. Firstly, a double-shell structure is used to circulate the high-temperature flue gas around the outer wall of the shell. Secondly, high-temperature flue gas is introduced into the stirring shaft tube, simultaneously heating both the outer wall of the shell and the inner wall of the stirring shaft. The heat is then transferred to the wet sludge through the shell and stirring shaft walls, evaporating and removing the moisture. The evaporated moisture is then drawn out of the shell by an induced draft fan and discharged after dust removal, dehumidification, and deodorization. After thermal drying and dewatering, the moisture content of the high-moisture sludge can reach between 10-30%. The adjustable function of the equipment can be used to control the moisture content of the sludge according to the subsequent needs for resource utilization of the dried sludge, achieving the goal of turning waste into treasure.

Claims

1. A partition wall sludge dryer, comprising: Shell assembly, flue gas circulation assembly, and stirring shaft assembly; The housing assembly includes: a hollow housing, with a feed inlet at the upper part of one end and a discharge outlet at the lower part of the other end, the feed inlet and the discharge outlet communicating with the inner cavity of the housing; and heat-absorbing fins arranged on the outside of the housing. Its features are: The flue gas recirculation assembly includes: a tubular flue gas recirculation shell and a flue gas hood, wherein the flue gas recirculation shell is welded to the heat-absorbing fins; the flue gas hoods are respectively disposed above and below the flue gas recirculation shell along the axial direction of the shell, and the upper and lower flue gas hoods are staggered; the inner cavities of the flue gas recirculation shell and the flue gas hood are interconnected, and a serpentine circulation cavity is formed between them and the shell; a flue gas inlet is provided at the lower part of one end of the flue gas recirculation shell, and a flue gas outlet is provided at the upper part of the other end; The stirring shaft assembly includes a stirring shaft and a rotary sealing device. The stirring shaft includes: a hollow tube, stirring blades, a stirring arc plate, and an inner spiral blade; the hollow tube is arranged in the inner cavity of the shell along the axial direction of the shell; the stirring blades are arranged on the outer wall of the hollow tube, and the stirring blades and the hollow tube are inclined at a preset angle in the radial direction and arranged in a spiral structure along the axial direction; the stirring arc plate is welded to one side of the stirring blades in the spiral direction, and the stirring arc plate is eccentrically arranged with the stirring blades; the inner spiral blades are arranged in the hollow tube along the axial direction, and the inner spiral blades and the inner wall of the hollow tube together form a spiral flue gas channel; The hollow tube has a flue gas inlet and a flue gas outlet at its two ends. It also includes: a power system, which comprises: a frequency-modulated reducer and a frequency-modulated induced draft fan; The stirring shaft is driven to rotate by the frequency-controlled reducer; the high-temperature flue gas entering the flue gas circulation assembly and the stirring shaft cavity is driven by the frequency-controlled induced draft fan. It also includes a carrier gas inlet and a carrier gas outlet disposed on the housing and communicating with the inner cavity of the housing.

2. The indirect-connection sludge dryer according to claim 1, characterized in that: The stirring shaft includes two shafts, which are simultaneously disposed in the inner cavity of the housing. The stirring blades on the two stirring shafts are installed in staggered positions on the outer wall of the hollow tube, and the two stirring shafts rotate in opposite directions.

3. The indirect-connection sludge dryer according to claim 1, characterized in that: The rotary sealing device includes a sealing seat and a sealing cover. The sealing seat is fixed to the stirring shaft with bolts and rotates together with the stirring shaft. The sealing cover is connected and fixed to the flue gas inlet and outlet pipes. The sealing seat and the sealing cover are non-contact labyrinth structures, and graphite packing is used to seal the gap between the two parts.

4. The indirect-connection sludge dryer according to claim 1, characterized in that: The spiral blades inside the tube are fixed at both ends along the axial direction of the hollow tube within the hollow tube cavity, and the height of the spiral blades inside the tube is adapted to the diameter of the hollow tube.

5. The indirect-connection sludge dryer according to claim 1, characterized in that: The carrier gas inlet is located at one end of the feed port, and the carrier gas outlet is located at one end of the discharge port and is located on the upper part of the housing.

6. The indirect-connection sludge dryer according to claim 1, characterized in that: The power system also includes a frequency-modulated induced draft fan for carrier gas, which drives the carrier gas entering the carrier gas inlet.

7. The indirect-connection sludge dryer according to claim 6, characterized in that, It also includes a control system, which uses the frequency-modulated reducer to control the rotation speed of the stirring shaft, thereby controlling the moisture content and output of the dried sludge; controls the flow speed of the flue gas in the flue gas circulation shell and the stirring shaft by controlling the frequency of the frequency-modulated induced draft fan, thereby controlling the heat exchange rate between the flue gas and the sludge; and regulates the temperature and humidity inside the shell by controlling the flow speed of the carrier gas using the frequency-modulated induced draft fan.

8. The partition wall sludge dryer according to claim 7, characterized in that, It also includes: remote pressure gauges and remote thermocouples. A set of remote pressure gauges and remote thermocouples are respectively installed at the flue gas inlet, the flue gas outlet and the carrier gas outlet to adapt to different operating conditions of the equipment. By controlling the frequency of the frequency-controlled induced draft fan and the frequency-controlled induced draft fan for the carrier gas, the pressure and temperature at the flue gas outlet and the carrier gas outlet can be controlled.

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