A porcelain double-cone dryer for preparing O-methyl-N-nitro-N-methyl isourea

Abstract

The application discloses a porcelain double-cone dryer for preparing O-methyl-N-nitro-N-methyl isourea, and relates to the technical field of isourea preparation. The porcelain double-cone dryer comprises a rack, a control module, a driving device, a drying kettle and a sealing cover structure. The control module is arranged on the rack and is used for controlling the operation of the drying device. The drying kettle is rotatably arranged on the rack. The driving device is installed on the rack and is in transmission connection with the drying kettle, and is used for driving the drying kettle to rotate around its own axis. The sealing cover structure is arranged at the end of the drying kettle and is used for sealing the kettle cavity of the drying kettle. Through cooperation of the rotary connecting seat, the buffer cavity, the shunt structure and the heat supplement runner, the application can continuously and stably convey the heat medium in the rotating state of the drying kettle, can directionally supplement heat to the main heat exchange area of the filter cake, can reduce the local wall temperature drop caused by repeated wall adhesion and heat absorption of the wet filter cake, and can improve the heat stability and drying uniformity of the O-methyl-N-nitro-N-methyl isourea filter cake.

Description

Technical Field

[0001] This invention relates to the field of isourea preparation technology, specifically to an enamel double cone dryer for the preparation of O-methyl-N-nitro-N-methylisourea. Background Technology

[0002] O-Methyl-N-nitro-N-methylisourea is a commonly used chemical intermediate. Its preparation typically involves reaction, crystallization, solid-liquid separation, and drying to obtain a product with a moisture content suitable for subsequent storage, transportation, or reaction use. After centrifugation or filtration, O-methyl-N-nitro-N-methylisourea usually exists as a filter cake. This filter cake still contains a certain amount of moisture or solvent. Insufficient drying can easily affect the product's stability, flowability, and subsequent performance. Therefore, it is necessary to further remove residual moisture using drying equipment to achieve a more stable dry state.

[0003] In existing technologies, the drying of filter cake materials is typically carried out using drying ovens, box-type dryers, or double-cone rotary vacuum dryers. Double-cone rotary vacuum dryers generally use the rotation of the tank or cylinder to agitate the material, combined with heating medium supply and vacuum dehumidification to complete the drying process. For example, Chinese Patent Publication No. CN215930388U discloses a double-cone rotary vacuum dryer, which includes a cylinder, a first frame, a second frame, a motor, a reducer, a first rotating head, a vacuum tube, a vacuum filter, a second rotating head, and a water inlet pipe. The motor and reducer drive the cylinder to rotate, causing the material inside the cylinder to continuously move up and down and inside and out. Dehumidification is achieved through the vacuum tube and vacuum filter, thereby increasing the drying speed of the material.

[0004] However, the O-methyl-N-nitro-N-methylisourea filter cake does not remain in a single loose state throughout the drying process. Instead, as moisture is gradually discharged, it gradually changes from an initial wet filter cake state to a semi-dry agglomerate state, and further forms loose particles or fine powder. The existing double cone rotary vacuum drying equipment mainly relies on the overall rotation of the cylinder, conventional heating, and vacuum suction to achieve drying. It is difficult to stably supplement the heat to the main heat exchange areas that the filter cake repeatedly contacts during the rotation process. When the wet filter cake continues to adhere to the vessel wall, it is easy to cause local heat to be quickly taken away, resulting in insufficient local heating. Summary of the Invention

[0005] The purpose of this invention is to provide an enamel double cone dryer for the preparation of O-methyl-N-nitro-N-methylisourea, so as to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: An enamel double cone dryer for the preparation of O-methyl-N-nitro-N-methylisourea includes a frame, a control module, a drive unit, a drying vessel, and a sealing structure. The control module is mounted on the frame, the drying vessel is rotatably mounted on the frame, the drive unit is mounted on the frame and connected to the drying vessel for driving the drying vessel to rotate around its own axis, and the sealing structure is located at the end of the drying vessel for sealing the cavity of the drying vessel. The drying kettle is equipped with a heating mechanism, a clump-breaking mechanism, and a suction mechanism. The heating mechanism is located in the installation cavity of the drying kettle wall and is used to heat the main contact area of ​​the filter cake inside the drying kettle. The clump-breaking mechanism is located inside the kettle cavity and is used to break up the semi-dry filter cake clumps with low shear. The suction mechanism includes an external suction component and an internal suction end that rotates synchronously with the drying kettle. The external suction component is connected to the internal suction end through a rotary sealing structure. The internal suction end extends into the kettle cavity and is used to suction out the water vapor inside the kettle cavity.

[0007] A further improvement of the technical solution of the present invention is as follows: the heat replenishment mechanism includes a guide plate, a buffer chamber, a rotating connecting seat, and a flow distribution structure. The guide plate is disposed in the installation cavity of the vessel wall and is provided with a heat replenishment flow channel. The buffer chamber is fixed to the end of the guide plate and communicates with the liquid inlet end of the heat replenishment flow channel. The rotating connecting seat includes a fixed connecting section and a rotating connecting section. The fixed connecting section is communicated with the conveying pipe through a connecting flange. The conveying pipe is used to communicate with an external heat source. The rotating connecting section is fixedly connected to the drying vessel and is rotatably sealed to the fixed connecting section, and is also connected to the output end of the driving device. A fixed liquid inlet channel is formed in the fixed connecting section, and a rotating liquid inlet channel is formed in the rotating connecting section. The two are communicated through the rotating sealing cavity, and the rotating liquid inlet channel is communicated with the buffer chamber. The flow distribution structure is disposed at the end of the rotating connecting section near the buffer chamber and extends at least partially into the buffer chamber for directional distribution of the heat medium to the heat replenishment flow channel.

[0008] A further improvement of the technical solution of the present invention is that: the diversion structure includes a diversion guide plate and a diversion seat. The diversion guide plate is disposed at one end of the rotating connecting section near the buffer cavity, and the diversion seat is fixed at the end of the rotating connecting section that extends into the buffer cavity; multiple diversion holes are spaced apart circumferentially on the outer periphery of the diversion seat, and a partition plate connected to the diversion guide plate is disposed inside the diversion seat to divert the heat medium to different diversion holes; two horizontal plates are disposed inside the buffer cavity, and the two horizontal plates are symmetrically disposed on the outside of the diversion seat, and together with the side wall of the buffer cavity, they form a main heat distribution area and an auxiliary heat insulation distribution area; some diversion holes are connected to the main heat distribution area, and other diversion holes are connected to the auxiliary heat insulation distribution area, and the total flow area of ​​the diversion holes corresponding to the main heat distribution area is greater than the total flow area of ​​the diversion holes corresponding to the auxiliary heat insulation distribution area.

[0009] A further improvement of the technical solution of the present invention is that: the heat replenishment mechanism further includes a constant temperature structure, which includes a constant temperature chamber, an electric heating module and ribs. The constant temperature chamber is disposed on the side of the guide plate away from the heat replenishment channel and is located in the mounting cavity; multiple electric heating modules are disposed on the side of the constant temperature chamber away from the guide plate, and their heating ends extend into the constant temperature chamber; multiple ribs are disposed on the side of the constant temperature chamber facing the guide plate, are thermally connected to the constant temperature chamber, and extend at least partially into the heat replenishment channel after passing through the guide plate, for transferring heat to the heat medium and disturbing the flow of the heat medium.

[0010] A further improvement of the technical solution of the present invention is that: an S-shaped heat replenishment channel is provided inside the guide plate, the S-shaped heat replenishment channel includes multiple linear heat exchange sections, a reversing section connecting adjacent linear heat exchange sections, and a flared guide section provided at the liquid inlet end; the rib is provided inside the linear heat exchange section and avoids the flared guide section and the reversing section; one end of the rib is thermally connected to the constant temperature chamber, and the other end extends into the linear heat exchange section, and its free end forms a flow gap with the opposite inner wall of the linear heat exchange section; the extension direction of the rib intersects with the mainstream direction of the heat medium in the linear heat exchange section.

[0011] A further improvement of the technical solution of the present invention is that: the rib includes a front end, a back end, and a heat-conducting main body. The front end is configured as an arc-shaped flow guide surface, and the back end is configured as an oblique turbulence end face. The arc-shaped flow guide surface and the oblique turbulence end face are connected through the heat-conducting main body, and the heat-conducting main body is thermally connected to the constant temperature chamber.

[0012] A further improvement of the technical solution of the present invention is that: the agglomeration breaking mechanism includes two fixed seats that are relatively fixed in the cavity of the drying vessel and rotate synchronously with the drying vessel. Multiple mounting bases are arranged between the two fixed seats. The multiple mounting bases are distributed at intervals along the circumference of the fixed seats and together form an open near-spherical agglomeration breaking frame. Multiple agglomeration breaking teeth are arranged at intervals along the extension direction of the inner side of the mounting bases for breaking the falling semi-dry filter cake agglomerates. Dispersion ribs are arranged on both sides of the agglomeration breaking teeth for laterally dispersing the semi-dry filter cake agglomerates.

[0013] A further improvement of the technical solution of the present invention is that: the tip of the agglomerating tooth is a rounded blunt head structure, and the root of the tooth is connected to the inner surface of the mounting base with a rounded transition; multiple agglomerating teeth are arranged with variable tooth pitch along the extension direction of the mounting base, and the mounting base includes sparse tooth segments at both ends and dense tooth segments in the middle, the spacing between adjacent agglomerating teeth in the dense tooth segments is smaller than the spacing between adjacent agglomerating teeth in the sparse tooth segments; the sparse tooth segments are used to introduce and pre-disperse the semi-dry filter cake agglomerates, and to allow the material dispersed by the dense tooth segments to fall back to the heating area after leaving the mounting base; the dense tooth segments are used to continuously extrude and disperse the semi-dry filter cake agglomerates; the cross-section of the dispersing rib is a rounded triangle, and its receiving edge is a rounded blunt edge.

[0014] A further improvement of the technical solution of the present invention is as follows: the suction mechanism includes a rotating block, a rotating connection structure, an output pipe, a guide pipe, a suction pipe, a filter structure, a protective cover, a protective frame, and a striking structure; the rotating block is fixedly installed at the end of the drying kettle away from the rotating connection seat, and is rotatably connected to the frame through the rotating connection structure on its outer periphery; the output pipe is set inside the rotating block, one end extends into the installation cavity of the kettle wall and communicates with the buffer cavity, and the other end is connected to the guide pipe, for exporting the heat medium to the external return pipeline; the suction pipe passes through the output pipe and is isolated from the output pipe, one end of the suction pipe is used to communicate with the external suction source, and the other end extends into the kettle cavity; the filter structure is set on the side of the drying kettle near the rotating block and communicates with the suction pipe; the protective cover is sleeved on the outside of the filter structure and is fixedly connected to the inner wall of the drying kettle, and a discharge channel is formed between the protective cover and the filter structure for the fallen material to fall back into the kettle cavity; the protective frame is set on the side wall of the protective cover, and the striking structure is set on the inner wall of the protective cover, for vibrating and cleaning the filter structure during the rotation of the drying kettle.

[0015] A further improvement of the technical solution of the present invention is that: the striking structure includes a mounting base, a swing arm, a striking block, a friction block, a fixing frame, and an elastic reset component. The mounting base is fixed to the inner wall of the protective frame, the swing arm is rotatably connected to the mounting base, and the striking block is fixed to the end of the swing arm away from the mounting base. The friction block is located on the inner wall of the protective frame near the swing path of the swing arm and is in frictional engagement with the bottom end of the swing arm to create resistance to the swing arm, causing it to swing backward relative to the protective frame. The fixing frame is located on both sides of the swing arm and connected to the filter structure. The striking block is used to strike the fixing frame to make the filter structure vibrate and clean the dust. The elastic reset component is located between the mounting base and the swing arm and is used to drive the swing arm to reset after the striking block hits the fixing frame.

[0016] By adopting the above technical solution, the technical effects achieved by this invention compared to the prior art are as follows: 1. This invention provides an enamel double cone dryer for the preparation of O-methyl-N-nitro-N-methylisourea. Through the cooperation of the rotating connecting seat, buffer chamber, flow distribution structure and heat replenishment channel, it can continuously and stably deliver heat medium while the drying kettle is rotating and provide directional heat replenishment to the main heat exchange area of ​​the filter cake. This can reduce the local wall temperature drop caused by repeated heat absorption by the wet filter cake, and improve the thermal stability and drying uniformity of the O-methyl-N-nitro-N-methylisourea filter cake.

[0017] 2. This invention provides an enamel double cone dryer for the preparation of O-methyl-N-nitro-N-methylisourea. Through the arrangement of a constant temperature chamber, an electric heating module, and ribs, it plays a role in continuously replenishing and turbulently equalizing the temperature of the heat medium in the heat replenishment channel. This makes it less likely for the heat medium to experience a significant temperature drop along the flow path due to continuous heat exchange during the flow of the heat medium along the S-shaped heat replenishment channel, thereby improving the continuity of heat replenishment and the heat exchange efficiency of the main heat exchange area of ​​the vessel wall.

[0018] 3. This invention provides an enamel double cone dryer for the preparation of O-methyl-N-nitro-N-methylisourea. It forms an open near-spherical agglomerating frame by enclosing multiple mounting bases, and agglomerating teeth and dispersing ribs are set on the inner side of the mounting bases. This serves to break up the semi-dry filter cake agglomerates with low shear by utilizing the rotation of the drying kettle itself and the weight of the material. This exposes the wet surface inside the agglomerates and allows them to fall back into the reheating area for continued drying, reducing the risk of the semi-dry agglomerates being dry on the outside and wet on the inside.

[0019] 4. This invention provides an enamel double cone dryer for the preparation of O-methyl-N-nitro-N-methylisourea. Through the rounded blunt head structure of the agglomeration breaking teeth, the rounded corner transition of the tooth root, the variable tooth pitch arrangement of sparse and dense tooth segments, and the rounded blunt edge setting of the dispersing ribs, it plays the role of sequentially introducing, pre-dispersing, continuously extruding and dispersing, and guiding and releasing semi-dry filter cake agglomerates. It can improve the agglomeration breaking effect while reducing excessive pulverization, material adhesion, and blockage caused by sharp cutting.

[0020] 5. This invention provides an enamel double cone dryer for the preparation of O-methyl-N-nitro-N-methylisourea. Through the cooperation of suction pipe, filter structure, protective cover, material discharge channel and knocking structure, it can intercept powder, protect filter structure and vibrate and clean the filter structure while extracting and expelling humid air in the dryer chamber. This allows the material attached to the surface of the filter structure to fall off and fall back into the dryer for continued drying, thereby reducing the risk of suction blockage and improving the stability of continuous dehumidification and material recovery rate. Attached Figure Description

[0021] The invention will now be further described with reference to the accompanying drawings.

[0022] Figure 1 This is a first-view schematic diagram of the overall device structure of the present invention; Figure 2 This is a second perspective view of the overall device structure of the present invention; Figure 3 This is a partial schematic diagram of the device structure of the present invention; Figure 4 This is a schematic diagram of the exploded structure of a portion of the device of the present invention; Figure 5 This is a schematic diagram of the heating mechanism of the present invention; Figure 6 This is a partial structural diagram of the heating mechanism of the present invention; Figure 7 This is a schematic diagram of the isothermal structure of the present invention; Figure 8 for Figure 7 Schematic diagram of the structure at point A in the middle; Figure 9 This is a schematic diagram of the granulation mechanism of the present invention; Figure 10 This is a first-view schematic diagram of the suction mechanism structure of the present invention; Figure 11 This is a second perspective view of the suction mechanism structure of the present invention.

[0023] In the diagram: 1. Frame; 2. Control module; 3. Drive unit; 4. Drying kettle; 5. Sealing structure; 6. Heating mechanism; 7. Agglomeration mechanism; 8. Suction mechanism; 9. Guide plate; 10. Buffer chamber; 11. Rotating connecting seat; 12. Connecting flange; 13. Conveying pipe; 14. Diverting guide plate; 15. Diverting seat; 16. Guide hole; 17. Separator plate; 18. Horizontal plate; 19. Constant temperature chamber; 20. Electric heating module; 21. Rib plate; 22. Fixed seat; 23. Mounting base; 24. Agglomeration teeth; 25. Dispersing ribs; 26. Rotating block; 27. Rotating connecting structure; 28. Output pipe; 29. ​​Guide pipe; 30. Suction pipe; 31. Filter structure; 32. Protective cover; 33. Protective frame; 34. Mounting seat; 35. Swing arm; 36. Impact block; 37. Fixed frame. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the embodiments.

[0025] Example 1

[0026] like Figures 1-4 As shown, the present invention provides an enamel double cone dryer for the preparation of O-methyl-N-nitro-N-methylisourea, comprising: a frame 1, a control module 2, a drive device 3, a drying vessel 4, and a sealing structure 5. The control module 2 is disposed on the frame 1, the drying vessel 4 is rotatably disposed on the frame 1, the drive device 3 is mounted on the frame 1 and is connected to the drying vessel 4 for driving the drying vessel 4 to rotate around its own axis, and the sealing structure 5 is disposed at the end of the drying vessel 4 for sealing the vessel cavity of the drying vessel 4. The drying vessel 4 is equipped with a heating mechanism 6, a clump-breaking mechanism 7, and a suction mechanism 8. The heating mechanism 6 is located in the installation cavity of the drying vessel 4 wall and is used to heat the main contact area of ​​the filter cake in the drying vessel 4. The clump-breaking mechanism 7 is located in the vessel cavity and is used to break up the semi-dry filter cake clumps with low shear. The suction mechanism 8 includes an external suction component and an internal suction end that rotates synchronously with the drying vessel 4. The external suction component is connected to the internal suction end through a rotary sealing structure. The internal suction end extends into the vessel cavity and is used to suction out the water vapor in the vessel cavity.

[0027] In this embodiment, during device operation, the control module 2 controls the drive device 3, the heating mechanism 6, the floc-breaking mechanism 7, and the suction mechanism 8 to work together. The drive device 3 drives the drying vessel 4 to rotate at a low speed around its own axis, and the sealing structure 5 keeps the vessel cavity in a relatively sealed drying environment. The O-methyl-N-nitro-N-methylisourea filter cake entering the vessel cavity repeatedly adheres to the wall, rises, turns over, spreads, and falls under the action of gravity and the rotation of the vessel. The wet filter cake has a high liquid content in the early stage of drying. Under the action of gravity, the wet filter cake mainly concentrates in the lower part of the vessel wall of the drying vessel 4, and repeatedly contacts the main heat exchange path of the vessel wall during the rotation of the drying vessel 4, continuously absorbing heat from this area. The heating mechanism 6 provides heating to the main contact area of ​​the filter cake, so that the filter cake can continuously obtain a relatively stable heat input during the repeated adhesion and fall. As the drying process progresses, the filter cake gradually changes from a wet and sticky state to a semi-dry agglomerated state. Some materials tend to form clumps with a relatively dry outer layer but still containing moisture inside. During the rotation of the drying vessel 4, the agglomeration breaking mechanism 7 performs low-shear breaking on these clumps, exposing the wet surface inside the clumps, which then fall back into the reheating area with the material to continue being heated and dried. At the same time, the suction mechanism 8 extracts and discharges the water vapor released from the vessel cavity through its internal suction end, maintaining a low-humidity environment inside the vessel cavity that is conducive to moisture migration and discharge. This forms a continuous drying process of "low-speed turning and spreading, reheating of the main area, breaking up of semi-dry clumps, and continuous extraction and discharge of water vapor".

[0028] Example 2

[0029] like Figure 4 , Figure 5 and Figure 6 As shown, based on Embodiment 1, the present invention provides a technical solution: Preferably, the heat replenishment mechanism 6 includes a guide plate 9, a buffer chamber 10, a rotating connecting seat 11, and a flow distribution structure. The guide plate 9 is disposed in the installation cavity of the vessel wall and has a heat replenishment flow channel. The buffer chamber 10 is fixed to the end of the guide plate 9 and communicates with the liquid inlet end of the heat replenishment flow channel. The rotating connecting seat 11 includes a fixed connecting section and a rotating connecting section. The fixed connecting section is communicated with the conveying pipe 13 through a connecting flange 12. The conveying pipe 13 is used to communicate with an external heat source. The rotating connecting section is fixedly connected to the drying vessel 4 and is rotatably sealed to the fixed connecting section, and is also drively connected to the output end of the driving device 3. A fixed liquid inlet channel is formed in the fixed connecting section, and a rotating liquid inlet channel is formed in the rotating connecting section. The two are communicated through a rotating sealing cavity, and the rotating liquid inlet channel is communicated with the buffer chamber 10. The flow distribution structure is disposed at one end of the rotating connecting section near the buffer chamber 10 and extends at least partially into the buffer chamber 10, for directional distribution of the heat medium to the heat replenishment flow channel.

[0030] In this embodiment, after the heat medium is output from an external heat source, it sequentially passes through the delivery pipe 13, connecting flange 12, fixed inlet channel, rotary sealing cavity, and rotary inlet channel into the buffer cavity 10. During the low-speed rotation of the drying vessel 4 with the drive device 3, the fixed connecting section remains relatively stationary, while the rotating connecting section rotates synchronously with the drying vessel 4. The rotary sealing cavity forms a continuous rotating communication space between the fixed connecting section and the rotating connecting section, allowing the heat medium to continuously enter the vessel wall mounting cavity of the drying vessel 4 without the external delivery pipe 13 rotating with the vessel body. After entering the buffer cavity 10, the heat medium is first collected and buffered, stabilizing the flow state of the heat medium output from the rotary inlet channel, and then introduced into the supplementary heating channel via a diversion structure. As the filter cake is affected by gravity and the rotation of the vessel during the rotation of the drying vessel 4, it mainly adheres to, flips and falls back to the main contact area of ​​the vessel wall. After continuously absorbing heat, the local wall temperature is prone to drop. Therefore, the diversion structure preferentially guides the heat medium to the heat replenishment channel corresponding to the main contact area of ​​the filter cake, so that the heat medium flows along the vessel wall area and continuously transfers heat to the main contact area of ​​the filter cake through the vessel wall, thus forming a heat replenishment process of "rotational liquid supply, buffered flow stabilization, directional diversion and key heat replenishment".

[0031] like Figure 5 and Figure 6 As shown, in this embodiment, preferably, the diversion structure includes a diversion guide plate 14 and a diversion seat 15. The diversion guide plate 14 is disposed at one end of the rotating connecting section near the buffer cavity 10, and the diversion seat 15 is fixed to the end of the rotating connecting section that extends into the buffer cavity 10. A plurality of diversion holes 16 are spaced apart circumferentially on the outer periphery of the diversion seat 15, and a partition plate 17 connected to the diversion guide plate 14 is disposed inside the partition plate 17 to divert the heat medium to different diversion holes 16. Two horizontal plates 18 are disposed inside the buffer cavity 10. The two horizontal plates 18 are symmetrically disposed on the outside of the diversion seat 15 and enclose the side wall of the buffer cavity 10 to form a main heat distribution area and an auxiliary heat insulation distribution area. Some of the diversion holes 16 are connected to the main heat distribution area, and other of the diversion holes 16 are connected to the auxiliary heat insulation distribution area. The total flow area of ​​the diversion holes 16 corresponding to the main heat distribution area is greater than the total flow area of ​​the diversion holes 16 corresponding to the auxiliary heat insulation distribution area.

[0032] In this embodiment, after the heat transfer medium enters the distribution seat 15 through the rotating inlet channel, it first enters different flow paths on both sides of the partition plate 17 under the guidance of the distribution guide plate 14, and is discharged into the main heat distribution area and the auxiliary heat preservation distribution area in the buffer chamber 10 through the corresponding guide holes 16. Since the total flow area of ​​the guide holes 16 corresponding to the main heat distribution area is larger than that of the guide holes 16 corresponding to the auxiliary heat preservation distribution area, the heat transfer medium forms a higher flow distribution ratio in the path with lower flow resistance, thus preferentially entering the heat transfer channel corresponding to the main contact area of ​​the filter cake; the other part of the heat transfer medium enters the auxiliary heat preservation distribution area with a smaller flow rate and enters the heat preservation channel or auxiliary heat transfer channel corresponding to the non-main contact area. During the low-speed rotation of the drying vessel 4, the filter cake repeatedly adheres to, flips, and falls under the action of gravity and the rotation of the vessel body. The main contact area is more prone to local wall temperature drop due to the continuous heat absorption of the wet filter cake. The main heat distribution zone can directionally transport more heat medium to this area for key heat replenishment, while the auxiliary heat preservation distribution zone provides basic heat preservation for other vessel wall areas. This forms a heat medium distribution process of "diversion introduction, zoned liquid drainage, priority heat replenishment in the main zone, and auxiliary heat preservation in the auxiliary zone".

[0033] like Figure 7 As shown, in this embodiment, preferably, the heat replenishment mechanism 6 further includes a constant temperature structure, which includes a constant temperature chamber 19, an electric heating module 20, and ribs 21. The constant temperature chamber 19 is disposed on the side of the guide plate 9 away from the heat replenishment channel and located in the mounting cavity. Multiple electric heating modules 20 are disposed on the side of the constant temperature chamber 19 away from the guide plate 9, and their heating ends extend into the constant temperature chamber 19. Multiple ribs 21 are disposed on the side of the constant temperature chamber 19 facing the guide plate 9, are thermally connected to the constant temperature chamber 19, and extend at least partially into the heat replenishment channel after passing through the guide plate 9, for transferring heat to the heat medium and disturbing the flow of the heat medium.

[0034] In this embodiment, as the heat medium flows along the supplementary heating channel and continuously transfers heat to the wall of the drying vessel 4, the heat medium will gradually experience a temperature drop along the flow path due to heat exchange with the vessel wall. Especially when the main contact area of ​​the filter cake continuously absorbs heat strongly, insufficient heating is likely to occur in the latter part of the supplementary heating channel. The electric heating module 20 continuously heats the constant temperature chamber 19, keeping it within the set temperature range, and transfers heat to the supplementary heating channel through the rib 21, which is thermally connected to the constant temperature chamber 19. When the heat medium flows through the location of the rib 21, the rib 21 can locally supplement the heat medium that has already experienced a temperature drop, allowing the heat medium to maintain a high heating capacity as it continues to flow. At the same time, after the rib 21 extends into the supplementary heating channel, it changes the local flow state of the heat medium, causing disturbance and mixing as the heat medium bypasses the rib 21, weakening the temperature boundary layer formed by the heat medium adhering to the channel wall, thereby improving the heat exchange efficiency between the heat medium and the guide plate 9 and the wall of the drying vessel 4. Therefore, based on the circulating heating of the heat medium, the heating mechanism 6 further forms an auxiliary heating process of "continuous heat storage in the constant temperature chamber 19, heat conduction and temperature compensation in the rib plate 21, and temperature uniformity due to heat medium disturbance", so that the kettle wall corresponding to the main contact area of ​​the filter cake can still maintain a relatively stable temperature under continuous heat absorption.

[0035] In a preferred embodiment, the set temperature of the constant temperature chamber 19 is not lower than the set temperature of the heat medium in the supplementary heating channel, and can be 0.5℃-2℃ higher than the set temperature of the heat medium in the supplementary heating channel. This temperature difference is used to compensate for the temperature drop along the flow path of the heat medium as it flows in the supplementary heating channel and transfers heat to the wall of the drying vessel 4, so that the ribs 21 can continuously provide heat compensation to the heat medium in the supplementary heating channel. The aforementioned temperature difference is not used to increase the actual drying temperature of the filter cake, but rather to maintain the temperature stability of the heat medium in the main supplementary heating area, avoiding localized temperature loss caused by continuous contact between the wet filter cake and the vessel wall.

[0036] like Figure 7 As shown, in this embodiment, preferably, an S-shaped heat replenishment channel is formed inside the guide plate 9. The S-shaped heat replenishment channel includes multiple linear heat exchange sections, a reversing section connecting adjacent linear heat exchange sections, and a flared guide section set at the liquid inlet end. The rib plate 21 is set inside the linear heat exchange section and avoids the flared guide section and the reversing section. One end of the rib plate 21 is thermally connected to the constant temperature chamber 19, and the other end extends into the linear heat exchange section, and a flow gap is formed between its free end and the opposite inner wall of the linear heat exchange section. The extension direction of the rib plate 21 intersects with the mainstream direction of the heat medium in the linear heat exchange section.

[0037] In this embodiment, when the heat medium enters the S-shaped heat exchange channel from the buffer chamber 10, it first undergoes a transitional introduction through the flared guide section, making the velocity change of the heat medium more gradual as it flows from the buffer chamber 10 to the straight heat exchange section, reducing local impact and flow resistance at the inlet end. The heat medium then forms a reciprocating flow path along multiple straight heat exchange sections and reversing sections, preventing the heat medium from flowing out directly through a short path after entering the guide plate 9, allowing the heat medium to maintain a longer flow path and heat exchange time in the main heat exchange area of ​​the drying vessel 4. During the flow of the heat medium along the straight heat exchange section, the rib plate 21 avoids the flared guide section and reversing section, only acting locally on the heat medium within the straight heat exchange section, so that the gradual introduction at the inlet end and the continuous reversal of the reversing section are not significantly disturbed. Because the rib 21 is thermally connected to the constant temperature chamber 19, the heat in the constant temperature chamber 19 can be transferred to the linear heat exchange section through the rib 21, providing localized heating for the heat medium flowing near the rib 21 that has already experienced a temperature drop along the flow path. Simultaneously, as the heat medium passes through the rib 21, it is blocked and guided by the rib 21, allowing it to continue flowing through the gaps between the sides of the rib 21 and the free end of the rib 21 and the opposite inner wall of the linear heat exchange section. During this flow, local disturbances are generated, causing the low-velocity heat medium layer close to the flow channel wall to mix with the heat medium in the middle of the flow channel, thereby weakening the temperature boundary layer and making the temperature distribution of the heat medium in the S-shaped heating channel more uniform. Thus, the heating mechanism 6 can form a continuous heating process of "expanded and gentle liquid inlet, S-shaped extended heat exchange, localized heating by the rib, and uniform temperature through flow disturbances," ensuring that the main contact area of ​​the drying vessel 4 wall maintains relatively stable heating conditions even under continuous heat absorption by the filter cake.

[0038] like Figure 8 As shown, in this embodiment, preferably, the rib 21 includes a front end, a back end, and a heat-conducting main body. The front end is configured as an arc-shaped flow guide surface, and the back end is configured as an oblique turbulence end surface. The arc-shaped flow guide surface and the oblique turbulence end surface are connected through the heat-conducting main body, and the heat-conducting main body is thermally connected to the constant temperature chamber 19.

[0039] In this embodiment, when the heat medium flows along the straight heat exchange section of the S-shaped heat exchange channel and passes through the rib 21, the heat medium first contacts the flow-facing end of the rib 21. The arc-shaped guide surface gently diverts the heat medium, allowing it to continue flowing along both sides of the rib 21 and the flow gap between the free end of the rib 21 and the inner wall of the opposite side of the straight heat exchange section. This avoids the heat medium directly impacting the end of the rib 21, which would cause significant pressure drop, backflow, or local stagnation. As the heat medium flows around the rib 21, the heat-conducting main body transfers heat from the constant temperature chamber 19 to the part of the rib 21 that extends into the heat exchange channel, and compensates for the heat medium flowing around it, thus mitigating the temperature drop that occurs after the heat medium flows along the straight heat exchange section. Subsequently, when the heat medium passes the oblique turbulence end face at the back flow end, the flow direction is locally deflected, and secondary turbulence is formed on the back flow side of rib 21, making it difficult for a stable stagnant zone to form on the back flow side. At the same time, it promotes the mixing of the heat medium near the flow channel wall with the heat medium in the middle of the flow channel, thereby weakening the temperature boundary layer. Thus, rib 21 forms a process of "gentle flow splitting at the front flow, heat conduction and temperature compensation in the main body, and turbulence mixing at the back flow" in the straight heat exchange section, so that the heat medium maintains a relatively continuous flow state and a relatively balanced temperature distribution in the heat compensation flow channel.

[0040] Example 3

[0041] like Figure 9 As shown, based on Embodiment 1, the present invention provides a technical solution: Preferably, the agglomeration breaking mechanism 7 includes two fixed seats 22 that are relatively fixed in the cavity of the vessel and rotate synchronously with the drying vessel 4. A plurality of mounting bases 23 are provided between the two fixed seats 22. The plurality of mounting bases 23 are distributed at intervals along the circumference of the fixed seats 22 and together form an open near-spherical agglomeration breaking frame. A plurality of agglomeration breaking teeth 24 are provided at intervals along the extension direction of the inner side of the mounting bases 23 for breaking the falling semi-dry filter cake agglomerates. Dispersion ribs 25 are provided on both sides of the agglomeration breaking teeth 24 for laterally dispersing the semi-dry filter cake agglomerates.

[0042] In this embodiment, during the low-speed rotation of the drying vessel 4, the semi-dry filter cake clumps are lifted as the vessel rotates and fall downwards or roll down the inner wall of the vessel cavity under gravity. When the clumps enter the open near-spherical breaking area formed by multiple mounting bases 23, the clumps can pass through the breaking area and continue to fall because there are open gaps between adjacent mounting bases 23, preventing large-area accumulation or blockage within the breaking mechanism 7. The multiple mounting bases 23 are distributed circumferentially along the fixed base 22, allowing the breaking teeth 24 to cover different material falling paths. As the drying vessel 4 continues to rotate, some mounting bases 23 and their breaking teeth 24 always pass through the material falling area, thereby increasing the contact probability between the semi-dry filter cake clumps and the breaking teeth 24. When the agglomerates come into contact with the breaking teeth 24, the teeth exert a low-speed squeezing, pushing, and dispersing effect on the agglomerates, gradually loosening larger agglomerates into smaller agglomerates or loose particles, and exposing the still-wet surface inside the agglomerates. As the agglomerates slide along the surface of the breaking teeth 24, the dispersing ribs 25 further exert a pushing and lateral splitting effect on the sides of the agglomerates, so that the agglomerates are subjected not only to positive agglomeration but also to lateral dispersion. The broken material continues to fall through the open gap between adjacent mounting bases 23 and falls back into the reheating area inside the drying kettle 4, allowing the newly exposed internal wet surface to continue to be heated and dried, thus forming a continuous drying process of "rotational lifting, gravity falling, low-shear agglomeration, wet surface exposure, and fall back for reheating".

[0043] like Figure 9 As shown, in this embodiment, preferably, the tip of the agglomerating tooth 24 is a rounded blunt head structure, and the root of the tooth is connected to the inner surface of the mounting base 23 with a rounded transition. Multiple agglomerating teeth 24 are arranged with variable tooth pitch along the extension direction of the mounting base 23. The mounting base 23 includes sparse tooth segments at both ends and dense tooth segments in the middle. The spacing between adjacent agglomerating teeth 24 in the dense tooth segments is smaller than the spacing between adjacent agglomerating teeth 24 in the sparse tooth segments. The sparse tooth segments are used to introduce and pre-disperse the semi-dry filter cake agglomerates, and to allow the material dispersed by the dense tooth segments to fall back to the heating area after leaving the mounting base 23. The dense tooth segments are used to continuously compress and disperse the semi-dry filter cake agglomerates. The cross-section of the dispersing rib 25 is a rounded triangle, and its receiving edge is a rounded blunt edge.

[0044] In this embodiment, during the low-speed rotation of the drying vessel 4, the semi-dry filter cake clumps are lifted by the rotation of the vessel body and then fall under the action of gravity, sequentially contacting different tooth segments on the mounting base 23. The clumps first enter the sparse tooth segment. Due to the large spacing between adjacent breaking teeth 24 in this area, the clumps can smoothly enter the breaking path and are slightly pushed, squeezed, and dispersed by the rounded blunt head structure, achieving initial introduction and pre-dispersion, avoiding the clumps from being concentratedly blocked by the dense tooth group when they first enter the breaking area and accumulating. After pre-dispersion, the clumps continue to enter the middle dense tooth segment. The spacing between adjacent breaking teeth 24 in the dense tooth segment is small, which can increase the probability of continuous contact between the breaking teeth 24 and the clumps, so that the clumps are gradually loosened under the continuous squeezing, pushing, and dispersing action of multiple rounded blunt head breaking teeth 24, and the wet surface inside the clumps that still contains water is exposed. Because the tips of the agglomeration breaking teeth 24 are rounded and blunt, the agglomerates are mainly subjected to low-shear compression and dispersion when they come into contact with the teeth 24, rather than sharp cutting action. This reduces the possibility of the material being instantly shredded into fine powder. As the agglomerates slide along the surface of the teeth 24, the rounded transition at the root of the teeth guides the material to smoothly detach from the connection area between the teeth 24 and the mounting base 23, reducing the adhesion, retention, or accumulation of material at the root of the teeth. The material, after being broken up by the dense tooth section, continues to enter the sparse tooth section at the other end. This sparse tooth section provides release space for the dispersed material, allowing it to smoothly detach from the mounting base 23 and fall back into the reheating area inside the drying vessel 4, so that the newly exposed internal wet surface can continue to receive reheating and drying.

[0045] It should be noted that the control module 2 can determine the drying stage of the filter cake based on at least one of the following: preset drying time, humidity of the vessel cavity, moisture content of the extracted gas, temperature difference between the inlet and outlet of the heating medium, and load changes of the drive device 3. When the preset drying time reaches the set value, or the humidity of the vessel cavity or the moisture content of the extracted gas decreases to the set range, or the temperature difference between the inlet and outlet of the heating medium or the load changes of the drive device 3 show a change characteristic corresponding to the turning of the semi-dry clumps, the control module 2 determines that the filter cake has entered the semi-dry clump stage and controls the drive device 3 to switch from continuous rotation drying mode to reciprocating oscillating breaking mode. When the initial moisture content of the filter cake is high, the control module 2 controls the drive device 3 to drive the drying vessel 4 to rotate at a low speed in the same direction, so that the wet filter cake turns over, spreads out and continuously contacts the heating area of ​​the vessel wall, thereby completing the initial dehydration and drying. When the filter cake gradually changes from a wet filter cake state to a semi-dry clump state, the control module 2 controls the drive device 3 to enter the reciprocating oscillating breaking mode, so that the drying vessel 4 is in a roughly horizontal state and oscillates back and forth within a preset angle range. At this time, the semi-dry filter cake clumps repeatedly slide, fall, and return within the drying vessel 4 under the influence of gravity, inertia, and the oscillation of the vessel body, passing through the area where the breaking mechanism 7 is located multiple times. This allows the semi-dry filter cake clumps to repeatedly contact the breaking teeth 24 and dispersing ribs 25 on the mounting base 23. Compared to the situation where the semi-dry clumps only fall along a relatively fixed path when the drying vessel 4 rotates continuously in one direction, the reciprocating oscillation breaking mode can change the falling path and contact number of the semi-dry clumps, allowing the clumps to gradually disperse under multiple low-shear collisions, compressions, and dispersing actions, and further exposing the still-wet surface inside the clumps. After the reciprocating oscillation breaking is completed, the control module 2 can control the drive device 3 to resume the continuous rotation drying mode, allowing the broken material to fall back to the heating area corresponding to the heating mechanism 6 to continue receiving heating and drying, while the suction mechanism 8 simultaneously discharges the water vapor from the vessel cavity. Through the above control method, the probability of repeated contact between the material and the breaking mechanism 7 can be increased in the semi-dry agglomeration stage, thereby improving the low-shear breaking effect, reducing the risk of increased fine powder caused by one-time strong crushing, and allowing the exposed internal wet surface to return to the heating area in time to continue drying, thereby improving the internal moisture release efficiency and overall drying uniformity of the semi-dry filter cake agglomerates.

[0046] Example 4

[0047] like Figure 10 and Figure 11As shown, based on Embodiment 1, the present invention provides a technical solution: Preferably, the suction mechanism 8 includes a rotating block 26, a rotating connection structure 27, an output pipe 28, a guide pipe 29, a suction pipe 30, a filter structure 31, a protective cover 32, a protective frame 33, and a striking structure; the rotating block 26 is fixedly installed on the end of the drying kettle 4 away from the rotating connection seat 11, and is rotatably connected to the frame 1 through the rotating connection structure 27 on its outer periphery; the output pipe 28 is disposed in the rotating block 26, one end extends into the installation cavity of the kettle wall and communicates with the buffer cavity 10, and the other end is connected to the guide pipe 29, for exporting the heat medium to the external return pipeline; The suction pipe 30 is inserted into the output pipe 28 and is isolated from the output pipe 28. One end of the suction pipe 30 is used to connect with an external suction source, and the other end extends into the vessel cavity. The filter structure 31 is set on the side of the drying vessel 4 near the rotating block 26 and is connected to the suction pipe 30. The protective cover 32 is sleeved on the outside of the filter structure 31 and is fixedly connected to the inner wall of the drying vessel 4. A feeding channel is formed between the protective cover 32 and the filter structure 31 for the dropped material to fall back into the vessel cavity. The protective frame 33 is set on the side wall of the protective cover 32, and the knocking structure is set on the inner wall of the protective cover 32 for vibrating and cleaning the filter structure 31 during the rotation of the drying vessel 4.

[0048] In this embodiment, during the rotary drying process of the drying vessel 4, the rotating block 26 rotates synchronously with the drying vessel 4 and provides rotational support for the drying vessel 4 through the rotating connection structure 27, so that the vessel body remains stable in a low-speed rotation state. The reheated heat medium enters the output pipe 28 through the buffer chamber 10, and then is discharged to the external return pipeline through the guide pipe 29, so that the heat medium can form a continuous return after completing the reheating of the vessel wall. Since the suction pipe 30 is inserted inside the output pipe 28 and isolated from the output pipe 28, the heat medium discharge path and the humid air suction path can operate independently in the same end area. The heat medium will not enter the suction pipe 30, and the humid air in the vessel cavity will not enter the output pipe 28. When the external suction source is working, the water vapor released from the filter cake drying process flows with the humid air in the vessel cavity to the filter structure 31. The humid air is filtered by the filter structure 31 before entering the suction pipe 30. The powder or fine materials entrained are intercepted on the outside of the filter structure 31. The filtered humid air is then discharged outward through the suction pipe 30, thereby reducing the humidity in the vessel cavity and promoting the continued outward migration of moisture inside the filter cake. During the process of the material turning, falling, and returning with the drying vessel 4, the protective cover 32 shields the filter structure 31, making it difficult for semi-dry lumps or particles to directly impact the filter structure 31. When powder adheres to the surface of the filter structure 31, the tapping structure intermittently or periodically vibrates the filter structure 31 as the drying kettle 4 rotates, causing the adhered powder to fall off. The material that falls off falls back into the kettle cavity through the feeding channel formed between the protective cover 32 and the filter structure 31 to continue drying. This forms a continuous dehumidification process of "independent reflux of hot medium, filtration and exhaust of humid air, protection of filter structure 31, vibration and dust removal, and material falling back for re-drying".

[0049] like Figure 10 and Figure 11 As shown, in this embodiment, preferably, the striking structure includes a mounting base 34, a swing arm 35, a striking block 36, a friction block, a fixing frame 37, and an elastic reset member. The mounting base 34 is fixed to the inner wall of the protective frame 33, the swing arm 35 is rotatably connected to the mounting base 34, and the striking block 36 is fixed to the end of the swing arm 35 away from the mounting base 34. The friction block is disposed on the inner wall of the protective frame 33 near the swing path of the swing arm 35 and frictionally engages with the bottom end of the swing arm 35 to impede the swing arm 35, causing it to swing backward relative to the protective frame 33. The fixing frame 37 is disposed on both sides of the swing arm 35 and connected to the filter structure 31. The striking block 36 is used to strike the fixing frame 37 to make the filter structure 31 vibrate and clean the dust. The elastic reset member is disposed between the mounting base 34 and the swing arm 35 and is used to drive the swing arm 35 to reset after the striking block 36 strikes the fixing frame 37.

[0050] In this embodiment, during the low-speed rotation of the drying vessel 4, the protective cover 32 and the protective frame 33 rotate synchronously with the drying vessel 4. The swing arm 35 and the striking block 36, affected by their own gravity and inertia, exhibit a tendency to sway with a lag relative to the protective frame 33. When the bottom end of the swing arm 35 passes the position of the friction block, the friction block impedes the swing arm 35, preventing it from immediately swaying synchronously with the protective frame 33. Instead, it forms a certain lag angle and swing torque during rotation. When this swing torque overcomes the frictional resistance of the friction block, the swing arm 35 swings rapidly around the mounting base 34, causing the striking block 36 to impact the fixed frame 37 connected to the filter structure 31. The impact force of the striking block 36 is transmitted to the filter structure 31 through the fixed frame 37, causing the filter structure 31 to vibrate instantaneously, thereby causing the powder or fine materials adhering to the surface of the filter structure 31 to loosen and fall off. After the impact is completed, the elastic reset component applies a reset action to the swing arm 35, causing the swing arm 35 to return to a position where it can engage with the friction block. As the drying kettle 4 continues to rotate, the swing arm 35, under the combined action of gravity hysteresis, frictional resistance, and elastic reset, repeatedly generates the actions of accumulating momentum, swinging, impacting, and resetting, so that the filter structure 31 obtains an intermittent rapping and dust-removing effect during the process of drawing in humid air. The powder or fine materials that have fallen off fall back into the drying kettle 4 through the feeding channel formed between the protective cover 32 and the filter structure 31, and continue to participate in the subsequent drying process.

[0051] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. An enamel double cone dryer for preparing O-methyl-N-nitro-N-methylisourea, comprising a frame (1), a control module (2), a drive device (3), a drying vessel (4), and a sealing structure (5), wherein the control module (2) is disposed on the frame (1), the drying vessel (4) is rotatably disposed on the frame (1), the drive device (3) is mounted on the frame (1) and is connected to the drying vessel (4) for driving the drying vessel (4) to rotate around its own axis, and the sealing structure (5) is disposed at the end of the drying vessel (4) for sealing the vessel cavity of the drying vessel (4), characterized in that: The drying vessel (4) is equipped with a heating mechanism (6), a floc breaking mechanism (7), and a suction mechanism (8). The heating mechanism (6) is located in the vessel wall mounting cavity of the drying vessel (4) and is used to heat the filter cake currently in the low-level vessel wall area of ​​the drying vessel (4). The heating mechanism (6) includes a guide plate (9), a buffer chamber (10), a rotating connecting seat (11), and a flow splitting structure. The guide plate (9) is located in the vessel wall mounting cavity and is provided with a heating channel. The buffer chamber (10) is fixed to the end of the guide plate (9) and communicates with the liquid inlet end of the heating channel. The rotating connecting seat (11) includes a fixed connecting section and a rotating connecting section. The connecting section is connected to the conveying pipe (13) via the connecting flange (12), and the conveying pipe (13) is used to connect to an external heat source; the rotating connecting section is fixedly connected to the drying kettle (4) and rotates and seals with the fixed connecting section, and is drivenly connected to the output end of the driving device (3); a fixed liquid inlet channel is formed in the fixed connecting section, and a rotating liquid inlet channel is formed in the rotating connecting section. The two are connected through a rotating sealing cavity, and the rotating liquid inlet channel is connected to the buffer cavity (10); the diversion structure is set at one end of the rotating connecting section near the buffer cavity (10) and extends at least partially into the buffer cavity (10) to directionally distribute the heat medium to the heat replenishment channel; The agglomeration breaking mechanism (7) includes two fixed seats (22) that are relatively fixed in the cavity of the dryer and rotate synchronously with the dryer (4). A plurality of mounting bases (23) are provided between the two fixed seats (22). The plurality of mounting bases (23) are distributed circumferentially along the fixed seats (22) and together form an open near-spherical agglomeration breaking frame. A plurality of agglomeration breaking teeth (24) are provided at intervals along the extension direction of the inner side of the mounting bases (23) for breaking the falling semi-dry filter cake agglomerates. Dispersion ribs (25) are provided on both sides of the agglomeration breaking teeth (24) for laterally dispersing the semi-dry filter cake agglomerates. The suction mechanism (8) includes an external suction component and an internal suction end that rotates synchronously with the drying vessel (4). The external suction component is connected to the internal suction end through a rotary sealing structure. The internal suction end extends into the vessel cavity to suction and discharge water vapor from the vessel cavity.

2. The enamel double-cone dryer for preparing O-methyl-N-nitro-N-methylisourea according to claim 1, characterized in that: The diversion structure includes a diversion guide plate (14) and a diversion seat (15). The diversion guide plate (14) is disposed at one end of the rotating connecting section near the buffer cavity (10), and the diversion seat (15) is fixed to the end of the rotating connecting section that extends into the buffer cavity (10). The diversion seat (15) has multiple diversion holes (16) spaced circumferentially on its outer periphery, and a partition plate (17) connected to the diversion guide plate (14) is disposed inside it to divert the heat medium to different diversion holes (16). Two horizontal plates (18) are provided inside the buffer cavity (10). The two horizontal plates (18) are symmetrically arranged outside the flow divider (15) and enclose the buffer cavity (10) sidewall to form a main heat distribution area and an auxiliary heat preservation distribution area. Some of the flow guide holes (16) are connected to the main heat distribution area, and the other part of the flow guide holes (16) are connected to the auxiliary heat preservation distribution area. The total flow area of ​​the flow guide holes (16) corresponding to the main heat distribution area is greater than the total flow area of ​​the flow guide holes (16) corresponding to the auxiliary heat preservation distribution area.

3. The enamel double-cone dryer for preparing O-methyl-N-nitro-N-methylisourea according to claim 2, characterized in that: The heating mechanism (6) also includes a constant temperature structure, which includes a constant temperature chamber (19), an electric heating module (20), and ribs (21). The constant temperature chamber (19) is located on the side of the guide plate (9) away from the heating channel and is located in the mounting cavity. Multiple electric heating modules (20) are located on the side of the constant temperature chamber (19) away from the guide plate (9), and their heating ends extend into the constant temperature chamber (19). Multiple ribs (21) are located on the side of the constant temperature chamber (19) facing the guide plate (9), are thermally connected to the constant temperature chamber (19), and extend at least partially into the heating channel after passing through the guide plate (9) to transfer heat to the heat medium and disturb the flow of the heat medium.

4. The enamel double-cone dryer for preparing O-methyl-N-nitro-N-methylisourea according to claim 3, characterized in that: The guide plate (9) has an S-shaped heat replenishment channel, which includes multiple straight heat exchange sections, a reversing section connecting adjacent straight heat exchange sections, and a flared guide section located at the liquid inlet. The rib (21) is located within the straight heat exchange section and avoids the flared guide section and the reversing section. One end of the rib (21) is thermally connected to the constant temperature chamber (19), and the other end extends into the straight heat exchange section, with a flow gap formed between its free end and the opposite inner wall of the straight heat exchange section. The extension direction of the rib (21) intersects with the mainstream direction of the heat medium in the straight heat exchange section.

5. The enamel double-cone dryer for preparing O-methyl-N-nitro-N-methylisourea according to claim 4, characterized in that: The rib (21) includes a front end, a back end, and a heat-conducting main body. The front end is configured as an arc-shaped flow guide surface, and the back end is configured as an oblique turbulence end face. The arc-shaped flow guide surface and the oblique turbulence end face are connected through the heat-conducting main body. The heat-conducting main body is thermally connected to the constant temperature chamber (19).

6. The enamel double-cone dryer for preparing O-methyl-N-nitro-N-methylisourea according to claim 5, characterized in that: The tip of the agglomeration teeth (24) is a rounded blunt head structure, and the root of the teeth is connected to the inner surface of the mounting base (23) with a rounded transition. Multiple agglomeration teeth (24) are arranged with variable tooth pitch along the extension direction of the mounting base (23). The mounting base (23) includes sparse tooth segments at both ends and dense tooth segments in the middle. The spacing between adjacent agglomeration teeth (24) in the dense tooth segments is smaller than the spacing between adjacent agglomeration teeth (24) in the sparse tooth segments. The sparse tooth segments are used to introduce and pre-disperse the semi-dry filter cake agglomerates, and to allow the material dispersed by the dense tooth segments to fall back to the heating area after leaving the mounting base (23). The dense tooth segments are used to continuously extrude and disperse the semi-dry filter cake agglomerates. The cross-section of the dispersing ribs (25) is a rounded triangle, and its receiving edge is a rounded blunt edge.

7. The enamel double-cone dryer for preparing O-methyl-N-nitro-N-methylisourea according to claim 6, characterized in that: The suction mechanism (8) includes a rotating block (26), a rotating connection structure (27), an output pipe (28), a guide pipe (29), a suction pipe (30), a filter structure (31), a protective cover (32), a protective frame (33), and a striking structure; the rotating block (26) is fixedly installed on the end of the drying vessel (4) away from the rotating connection seat (11), and is rotatably connected to the frame (1) through the rotating connection structure (27) on its outer periphery; the output pipe (28) is set inside the rotating block (26), one end extends into the installation cavity of the vessel wall and communicates with the buffer cavity (10), and the other end is connected to the guide pipe (29) for exporting the heat medium to the external return pipeline; the suction pipe (30) passes through the output pipe (28). Inside, and isolated from the output pipe (28), one end of the suction pipe (30) is used to connect with an external suction source, and the other end extends into the vessel cavity; the filter structure (31) is set on the side of the drying vessel (4) near the rotating block (26) and is connected to the suction pipe (30); the protective cover (32) is sleeved on the outside of the filter structure (31) and fixedly connected to the inner wall of the drying vessel (4), and a feeding channel is formed between the protective cover (32) and the filter structure (31) for the dropped material to fall back into the vessel cavity; the protective frame (33) is set on the side wall of the protective cover (32), and the knocking structure is set on the inner wall of the protective cover (32) for vibrating and cleaning the filter structure (31) during the rotation of the drying vessel (4).

8. The enamel double-cone dryer for preparing O-methyl-N-nitro-N-methylisourea according to claim 7, characterized in that: The striking structure includes a mounting base (34), a swing arm (35), a striking block (36), a friction block, a fixing frame (37), and an elastic reset component. The mounting base (34) is fixed to the inner wall of the protective frame (33). The swing arm (35) is rotatably connected to the mounting base (34). The striking block (36) is fixed to the end of the swing arm (35) away from the mounting base (34). The friction block is located on the inner wall of the protective frame (33) near the swing path of the swing arm (35) and is positioned in conjunction with the swing arm (35). The bottom friction fit is used to impede the swing arm (35), causing it to swing backward relative to the protective frame (33); the fixed frame (37) is set on both sides of the swing arm (35) and connected to the filter structure (31); the striking block (36) is used to strike the fixed frame (37) to make the filter structure (31) vibrate and clean the dust; the elastic reset member is set between the mounting base (34) and the swing arm (35) and is used to drive the swing arm (35) to reset after the striking block (36) hits the fixed frame (37).

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