A method and apparatus for purging caprolactam crystallizer feed nozzle blockages

Abstract

The application relates to the technical field of chemical equipment, and discloses a purging method and device for blockage of a caprolactam crystallizer feeding nozzle, which comprises a crystallizer body, a cylinder cover is fixedly installed at the top end of the crystallizer body, and a redundant steam supply assembly is arranged outside the crystallizer body. The method and device confirm the system pressure and temperature before purging, monitor the pressure drop of the steam branch pipe through a differential pressure transmitter, adopt pulse steam supply through a dry pipe during the purging process, open a manual stop valve, a spring-loaded check valve and corresponding blind plate isolation devices, and steam is blown from the corresponding steam branch pipe to the feeding nozzle body with blockage, so that the blockage is significantly dredged, the working efficiency of the feeding nozzle body is improved, the long-term stability and reliability of ammonia gas and rearranged liquid feeding are ensured, and the parking hidden danger caused by blockage of the feeding nozzle body is reduced.

Description

Technical Field

[0001] This invention relates to the field of chemical equipment technology, specifically to a purging method and apparatus for clogging the feed nozzle of a caprolactam crystallizer. Background Technology

[0002] Caprolactam is an important organic chemical raw material and a monomer for the production of nylon 6 fiber (i.e., nylon) and nylon 6 engineering plastics. It is widely used in the automotive, textile, electronics, and machinery industries. In the caprolactam production process, the rearrangement liquid from the rearrangement station and the gaseous ammonia from the ammonia oxime process undergo a neutralization reaction in the neutralization crystallizer to produce ammonium sulfate. The gaseous ammonia and the rearrangement liquid enter through four nozzles on the inner ring distributor of the crystallizer, respectively. The caprolactam reacts with sulfuric acid to produce ammonium sulfate and generate crystal nuclei.

[0003] The feed nozzles of existing crystallizers are prone to clogging. Traditional purging methods only install steam purging pipelines in the main feed pipes of gaseous ammonia and refluxing liquid. Purging operations require stopping the feed of the crystallizer system, which causes significant disturbance to the production processes before and after. When the unblocking takes a long time, it can easily lead to process reduction, directly reducing caprolactam production, increasing production costs and reducing production efficiency.

[0004] In view of this, we propose a purging method and apparatus for clogging the feed nozzle of a caprolactam crystallizer. Summary of the Invention

[0005] The purpose of this invention is to provide a purging method and apparatus for clogging the feed nozzle of a caprolactam crystallizer, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A purging method and apparatus for clogging the feed nozzle of a caprolactam crystallizer includes a crystallizer body, a cylinder cover fixedly installed at the top of the crystallizer body, an exhaust pipe fixedly installed on the cylinder cover, a one-way exhaust valve provided on the exhaust pipe, the exhaust pipe being connected to the input end of a waste gas collection device, the crystallizer body being fixedly installed on a frame, two sets of feed nozzle bodies having their discharge ends fixedly installed on the inner circumference of the crystallizer body, the feed ends of the two sets of feed nozzle bodies being respectively connected to the output ends of ammonia gas supply and a refluxing liquid supply device through feed pipes, a feed valve being provided on the feed pipe, and a redundant steam supply assembly being provided on the outside of the crystallizer body; The redundant steam supply assembly includes two main steam distribution pipes, which are located on the outer periphery of the crystallizer body. The outlet of each main steam distribution pipe is fixedly connected to multiple steam branch pipes, and the ends of the multiple steam branch pipes are fixedly connected to the inlet of the corresponding feed nozzle body. The inlet of the main steam distribution pipe is connected to the output of the pulse steam supply equipment through a trunk pipe. A three-level safety protection assembly is also provided on the outside of the crystallizer body.

[0007] In a further embodiment, the three-stage safety protection components are arranged sequentially along the steam flow direction, and the three-stage safety protection components include a manual shut-off valve, which is fixedly installed on the main pipeline.

[0008] In a further embodiment, the main steam distribution pipe is equipped with multiple sets of spring-loaded check valves, with two adjacent spring-loaded check valves mirrored on the outside of a single steam branch pipe. A blind flange isolation device is fixedly installed on the steam branch pipe by a double-bolt fastening structure. Under normal non-purging conditions, the blind flange forms a physical isolation, effectively preventing reverse permeation of ammonia-containing media and redistribution liquid within the crystallizer body.

[0009] In a further embodiment, a differential pressure transmitter is fixedly installed on the steam branch pipe, and the detection end of the differential pressure transmitter is sealed and connected to the inner wall of the steam branch pipe to monitor the pressure drop of the steam branch pipe.

[0010] In a further embodiment, a nitrogen replacement assembly is provided on the steam branch pipe. The nitrogen replacement assembly includes a nitrogen branch, which is welded and fixed to the steam branch pipe. A one-way inlet valve is provided on the nitrogen branch, and the nitrogen branch is connected to an external nitrogen source.

[0011] In a further embodiment, the main steam distribution pipe, steam branch pipe, and trunk line are all made of 316L stainless steel to ensure their corrosion resistance and mechanical strength.

[0012] In a further embodiment, the crystallizer body is equipped with an auxiliary component, which includes a rotating shaft. The rotating shaft is rotatably mounted inside the center of the bottom end of the crystallizer body via a sealed bearing. A servo motor is mounted at the bottom end of the crystallizer body, and a drive gear is fixedly mounted at the output end of the servo motor. A driven gear is fixedly mounted at the bottom end of the rotating shaft, and the drive gear meshes with the driven gear. A connector is fixedly mounted at the top of the rotating shaft, and two mirror-shaped stirring rods are fixedly mounted on the connector. A stirring plate is fixedly mounted on the stirring rods. A stirring paddle is fixedly mounted outside the rotating shaft and is located inside the crystallizer body. A connecting rod is also fixedly mounted on the connector, and a scraper is fixedly mounted on the connecting rod. The scraper slides against the arc-shaped inner wall of the crystallizer body, resulting in better mixing of the mixture.

[0013] In a further embodiment, a monitoring component is provided on the rotating shaft. The monitoring component includes a bend, which is fixedly installed at one end of the connector. A pressure sensor is fixedly installed inside the bend at the end away from the connector, and a processor is fixedly installed outside the bend at the end near the connector. The inside of the bend is hollow for wiring, thereby improving the practicality of the device.

[0014] In a further embodiment, the bottom output end of the crystallizer body is provided with a feeding mechanism for discharging material.

[0015] A purging method for clogging the feed nozzle of a caprolactam crystallizer, using the aforementioned purging device, includes the following steps: S1. System status confirmation and blockage monitoring: Before purging, confirm the system pressure and temperature, and monitor the pressure drop of the steam branch pipe in real time through the differential pressure transmitter to determine whether the feed nozzle body is blocked. S2. Open the steam flow pipeline, open the manual shut-off valve and spring-loaded check valve, and open the corresponding blind flange isolation device to open the steam flow pipeline. S3. Pulse steam supply start-up: Start the pulse steam supply equipment, and the steam is transported to the corresponding steam distribution main pipe through the main pipeline to establish the purging gas source. S4. Pulse purging and unblocking: Steam is blown directionally through the steam branch pipe to the blocked feed nozzle body, and the feed nozzle body is purged and unblocked in a pulse steam supply mode. S5. Nitrogen purging and system reset: After purging, shut off the steam supply, open the one-way inlet valve on the nitrogen branch, and purge the inside of the crystallizer body with nitrogen. After the purging meets the standard, close the one-way inlet valve and reset the blind plate isolation device.

[0016] Compared with the prior art, the present invention provides a purging method and apparatus for clogging the feed nozzle of a caprolactam crystallizer, which has the following beneficial effects: 1. This purging method and apparatus for clogging the feed nozzle of a caprolactam crystallizer, in conjunction with multiple sets of feed nozzle bodies, feed pipes, and feed valves, delivers a target amount of gaseous ammonia and rearranged liquid into the crystallizer body. By setting up redundant steam supply components and a three-stage safety protection system, the system pressure and temperature are confirmed before purging. The pressure drop in the steam branch pipe is monitored via a differential pressure transmitter. When ΔP ≥ 0.15 MPa, a feed nozzle body clogging alarm is triggered. During the purging process, pulsed steam supply is used through the main pipeline, and the duration of each purging cycle is controlled. Steam enters the steam distribution... By connecting the main pipe and opening the manual shut-off valve, spring-loaded check valve, and corresponding blind flange isolation device, steam is blown from the corresponding steam branch pipe to the blocked feed nozzle body, resulting in a significant unblocking effect. By adding a separate steam purging pipeline to each feed nozzle body, the blocked feed nozzle body can be purged individually without stopping the crystallizer body, which greatly improves the efficiency of unblocking the feed nozzle body, ensures the long-term stability and reliability of gaseous ammonia and refluxing liquid feed, and reduces the risk of shutdown caused by feed nozzle body blockage.

[0017] 2. The purging method and apparatus for clogging the feed nozzles of caprolactam crystallizers significantly reduces the number of shutdowns caused by clogging, greatly reduces the possibility of output reduction in upstream and downstream processes, achieves stable production of caprolactam products, increases the effective operating time of the equipment, saves a lot of maintenance costs and downtime losses, and has obvious economic benefits. At the same time, it does not require changing the main structure of the original crystallizer body, but only requires adding steam purging pipelines to each feed nozzle body. It is simple to implement, has low modification costs, and is conducive to promotion and application on existing equipment.

[0018] 3. This purging method and apparatus for clogging the feed nozzle of a caprolactam crystallizer, in order to improve the safety of the apparatus, incorporates a nitrogen replacement component. After purging, nitrogen replacement is performed by opening the one-way inlet valve on the nitrogen branch and closing the blind flange isolation device. The purpose is to completely replace the residual air and steam in the steam branch with nitrogen. The residual air and steam in the steam branch are continuously discharged to the waste gas collection equipment through the one-way outlet valve, reducing the oxygen content in the pipeline to below 0.5 vol%, meeting the safety requirements of ExdⅡCT4 explosion-proof areas, eliminating the risk of combustion and explosion, preventing steam condensation from forming negative pressure that could damage valves and instruments, ensuring the safe and stable operation of the apparatus, and thus improving the safety of the apparatus.

[0019] 4. The purging method and apparatus for clogging the feed nozzle of the caprolactam crystallizer, in order to improve the mixing effect of the mixture, by setting auxiliary components, when the servo motor is started, the driving gear rotates, and the driven gear drives the rotating shaft to rotate, thereby driving the stirring paddle to rotate for preliminary mixing. The connector will rotate synchronously, driving the two sets of stirring rods and stirring plates to rotate synchronously, so as to improve the mixing effect. The connecting rod will drive the scraper to rotate synchronously, which, while assisting the mixing, prevents the mixture from adhering to the inner wall of the crystallizer body. Finally, the material is discharged to the downstream equipment through the feeding mechanism.

[0020] 5. The purging method and apparatus for clogging the feed nozzle of the caprolactam crystallizer, in order to improve the practicality of the apparatus, a monitoring component is set up. When the connector rotates, it drives the bent pipe to rotate synchronously, so that the pressure sensor will make positive contact with the mixture and monitor the pressure value in real time. The more viscous the mixture, the higher the monitored pressure value, and vice versa. In conjunction with the processor, the value is sent to the controller to convert the pressure value into the viscosity of the mixture, thereby facilitating the subsequent material feeding control and improving the practicality of the apparatus. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention from another perspective; Figure 3 This is a schematic diagram of the connection of some parts of the structure of the present invention; Figure 4 For the present invention Figure 3 Enlarged structural diagram of region A in the middle; Figure 5 This is a schematic cross-sectional view of the main steam distribution pipe of the present invention; Figure 6 For the present invention Figure 5 Enlarged structural diagram of region B in the middle; Figure 7 This is a cross-sectional schematic diagram of the crystallizer body of the present invention; Figure 8 This is a schematic diagram of the cross-section of the rotating shaft of the present invention; Figure 9 This is a flowchart of the overall method of the present invention.

[0022] Explanation of icon numbers: 1. Crystallizer body; 11. Cylinder cover; 12. Exhaust pipe; 13. One-way exhaust valve; 2. Frame; 3. Feed nozzle body; 31. Feed pipe; 32. Feed valve; 4. Redundant steam supply assembly; 41. Main steam distribution pipe; 42. Branch steam pipe; 421. Double bolt fastening structure; 43. Main pipeline; 5. Three-level safety protection assembly; 51. Manual shut-off valve; 52. Spring-loaded check valve; 53. Blind flange isolation device; 6. 1. Differential pressure transmitter; 7. Nitrogen purging assembly; 71. Nitrogen branch; 72. One-way inlet valve; 8. Auxiliary assembly; 81. Rotary shaft; 821. Servo motor; 822. Drive gear; 823. Driven gear; 83. Connector; 84. Stirring rod; 85. Stirring plate; 86. Stirring paddle; 87. Connecting rod; 88. Scraper; 9. Monitoring assembly; 91. Bend; 92. Pressure sensor; 93. Processor; 10. Feeding mechanism. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In this application, the term "above" indicates the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. It is primarily used to better describe this application and its embodiments, and is not intended to limit the indicated device, element, or component to having a specific orientation, or to construct and operate in a specific orientation. Furthermore, the term "above" may also be used in certain circumstances to indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances.

[0025] Please see Figures 1-9 The present invention provides a technical solution: A purging method and apparatus for clogging the feed nozzles of a caprolactam crystallizer includes a crystallizer body 1, a cylinder cover 11 fixedly installed at the top of the crystallizer body 1, an exhaust pipe 12 fixedly installed on the cylinder cover 11, a one-way exhaust valve 13 provided on the exhaust pipe 12, and the exhaust pipe 12 connected to the input end of a waste gas collection device. The crystallizer body 1 is fixedly installed on a frame 2. Two sets of eight feed nozzle bodies 3 are fixedly installed at the discharge ends of the inner circumference of the crystallizer body 1. The feed ends of the two sets of feed nozzle bodies 3 are respectively connected to gaseous ammonia and heavy ammonia through feed pipes 31. At the output end of the liquid supply equipment, a feed valve 32 is installed on the feed pipe 31. Additionally, a discharge mechanism 10 for discharging material is installed at the bottom output end of the crystallizer body 1. A redundant steam supply assembly 4 is installed outside the crystallizer body 1. The redundant steam supply assembly 4 includes two steam distribution main pipes 41, which are located on the outer periphery of the crystallizer body 1. The outlet end of each steam distribution main pipe 41 is fixedly connected to four steam branch pipes 42. The ends of the four steam branch pipes 42 are fixedly connected to the inlet ends of the corresponding feed nozzles 3. The steam inlet of the main steam distribution pipe 41 is connected to the output of the pulse steam supply equipment via the branch pipe 43. Furthermore, the main steam distribution pipe 41, steam branch pipes 42, and branch pipe 43 are all made of 316L stainless steel to ensure corrosion resistance and mechanical strength. A three-stage safety protection assembly 5 is also installed on the exterior of the crystallizer body 1. This assembly is arranged sequentially along the steam flow direction and includes a manual shut-off valve 51, which is fixedly installed on the branch pipe 43. Additionally, the main steam distribution pipe 41 is equipped with… There are four sets of spring-loaded check valves 52. Two adjacent spring-loaded check valves 52 are mirrored on the outside of a single steam branch pipe 42. A blind plate isolation device 53 is fixedly installed on the steam branch pipe 42 by a double bolt fastening structure 421. Under normal non-purging conditions, the blind plate forms physical isolation, effectively preventing the reverse permeation of ammonia-containing media and redistribution liquid in the crystallizer body 1. In addition, a differential pressure transmitter 61 is fixedly installed on the steam branch pipe 42. The detection end of the differential pressure transmitter 61 is sealed and connected to the inner wall of the steam branch pipe 42 to monitor the pressure drop of the steam branch pipe 42.

[0026] In one embodiment of the present invention, a nitrogen replacement assembly 7 is provided on the steam branch pipe 42. The nitrogen replacement assembly 7 includes a nitrogen branch 71, which is welded and fixed to the steam branch pipe 42. A one-way air inlet valve 72 is provided on the nitrogen branch 71, and the nitrogen branch 71 is connected to an external nitrogen source.

[0027] In one embodiment of the present invention, an auxiliary component 8 is provided on the crystallizer body 1. The auxiliary component 8 includes a rotating shaft 81, which is rotatably mounted inside the center of the bottom end of the crystallizer body 1 via a sealed bearing. A servo motor 821 is provided at the bottom end of the crystallizer body 1. A drive gear 822 is fixedly mounted on the output end of the servo motor 821. A driven gear 823 is fixedly mounted at the bottom end of the rotating shaft 81. The drive gear 822 meshes with the driven gear 823. A connector 83 is fixedly mounted on the top of the rotating shaft 81. Two mirror-arranged stirring rods 84 are fixedly mounted on the connector 83. A stirring plate 85 is fixedly mounted on the stirring rods 84. A stirring paddle 86 is fixedly mounted on the outside of the rotating shaft 81. The stirring paddle 86 is located inside the crystallizer body 1. A connecting rod 87 is also fixedly mounted on the connector 83. A scraper 88 is fixedly mounted on the connecting rod 87. The scraper 88 slides against the arc-shaped inner wall of the crystallizer body 1, so that the mixture has a better mixing effect.

[0028] In one embodiment of the present invention, a monitoring component 9 is provided on the rotating shaft 81. The monitoring component 9 includes a bent tube 91, which is fixedly installed at one end of the connector 83. A pressure sensor 92 is fixedly installed inside the end of the bent tube 91 away from the connector 83, and a processor 93 is fixedly installed outside the end of the bent tube 91 near the connector 83. The inside of the bent tube 91 is hollow for wiring, which improves the practicality of the device.

[0029] A purging method for clogging the feed nozzle of a caprolactam crystallizer, using the aforementioned purging device, includes the following steps: S1. System status confirmation and blockage monitoring: Before the purging operation begins, confirm that the pressure and temperature of the crystallizer body 1 and the steam supply system are within the safe operating range; collect and monitor the pressure drop changes inside the steam branch pipe 42 in real time through the differential pressure transmitter 61, and determine whether the feed nozzle body 3 is blocked based on the pressure drop value, and determine the target feed nozzle body 3 that needs to be purged. S2. Open the steam flow pipeline, and along the steam delivery direction, sequentially open the manual shut-off valve 51 installed on the main pipeline 43 and the spring-loaded check valve 52 on the steam branch pipe 42, and open the blind plate isolation device 53 on the corresponding steam branch pipe 42, so that a complete and unobstructed purging passage is formed between the steam supply pipeline and the feed nozzle body 3. S3. Pulse steam supply start-up: Start the pulse steam supply equipment to output steam in pulse form; The steam is transported to the corresponding steam distribution main pipe 41 through the main pipe 43, and pressure stabilization and distribution are completed in the steam distribution main pipe 41 to establish a stable and reliable purging gas source. S4. Pulse purging and unblocking: Steam in the main steam distribution pipe 41 is directionally transported through the corresponding steam branch pipe 42 and blown directly onto the feed nozzle body 3 that has been identified as blocked; the pulse steam supply method continuously acts on the inside of the feed nozzle body 3, and the impact force of the pulse steam is used to clear the blockage and complete the purging and unblocking of the feed nozzle body 3. S5. Nitrogen Replacement and System Reset: After purging and unblocking, shut down the pulse steam supply equipment and steam supply passage; open the one-way inlet valve 72 on the nitrogen branch 71, and introduce nitrogen into the steam branch pipe 42 and the crystallizer body 1 for replacement, replacing the residual steam and air in the pipeline with nitrogen; when the nitrogen replacement reaches the safety standard, close the one-way inlet valve 72 and reset the blind plate isolation device 53 to complete the system reset.

[0030] Working principle: I. Normal Production and Operation Phase Ammonia gas and the drained liquid are conveyed through the feed pipe 31, and the flow rate is controlled by the feed valve 32. They are sprayed into the crystallizer body 1 through the feed nozzle body 3. Inside the crystallizer body 1, the ammonia gas and the drained liquid undergo a neutralization reaction to generate ammonium sulfate. The servo motor 821 drives the drive gear 822 to rotate, which drives the driven gear 823 to rotate synchronously with the rotating shaft 81. The rotating shaft 81 drives the stirring paddle 86, stirring rod 84, and stirring plate 85 to complete the material mixing. The connecting rod 87 drives the scraper 88 to rotate against the inner wall of the crystallizer body 1 to prevent material adhesion. The pressure sensor 92 monitors the material pressure as the bend pipe 91 rotates. The processor 93 converts the pressure signal into consistency data to realize real-time monitoring of the production status. After the reaction is completed, the material is discharged through the feeding mechanism 10. The waste gas generated by the reaction is conveyed to the waste gas collection equipment through the exhaust pipe 12 and the one-way exhaust valve 13. The three-level safety protection component 5 is in the closed state, the manual shut-off valve 51 is closed, the spring-loaded check valve 52 is closed, the blind plate isolation device 53 is in the physical isolation state to prevent the ammonia-containing medium from back-flowing into the drained liquid, and the differential pressure transmitter 61 continuously monitors the pressure drop of the steam branch pipe 42. When there is no blockage, the pressure drop is normal and no alarm is triggered.

[0031] II. Nozzle Clogging Monitoring and Judgment Stage When the feed nozzle body 3 becomes blocked, the pressure drop of the steam branch pipe 42 increases. When the differential pressure transmitter 61 detects a pressure drop ΔP ≥ 0.15 MPa, it triggers a nozzle blockage alarm. The operator confirms the location of the blocked feed nozzle body 3 and prepares to start the purging procedure. Before purging, the steam supply system pressure is checked to be ≥ 0.8 MPa gauge pressure and temperature is ≥ 185℃ to meet the purging start conditions.

[0032] III. Purging Pipeline Opening Stage Open the manual shut-off valve 51 and the spring-loaded check valve 52 on the main pipeline 43 to open the main steam passage, release the blind plate isolation device 53 fixed by the double bolt fastening structure 421 to eliminate physical isolation, establish the steam branch passage, and make the steam branch pipe 42 completely connected to the feed nozzle body 3.

[0033] IV. Pulse-type purging execution phase The pulse steam supply system is activated, and steam is delivered to the main steam distribution pipe 41 via the main pipe 43. The steam is then directed along the branch pipe 42 to the clogged feed nozzle body 3. Pulsating is performed using a 15s / 5s on / off cycle. The pulsed steam impact force removes blockages with a diameter ≤2mm from the inner diameter of the feed nozzle body 3, restoring the nozzle flow area to over 98% of the design value. Each purging cycle is controlled to 3-5 minutes to complete the removal of blockages. By adding a separate steam purging pipeline to each feed nozzle body 3, individual purging of the clogged feed nozzle body 3 can be achieved without stopping the crystallizer body 1, greatly improving the efficiency of clearing blockages. The improved efficiency of the feed nozzle body 3 ensures the long-term stability and reliability of the ammonia gas and the refluxing liquid feed, reduces the risk of shutdown caused by the blockage of the feed nozzle body 3, significantly reduces the number of shutdowns caused by blockage, greatly reduces the possibility of reduction in output in the upstream and downstream processes, realizes the stable production of caprolactam products, improves the effective operating time of the unit, saves a lot of maintenance costs and shutdown losses, and has obvious economic benefits. At the same time, it does not require changing the main structure of the original crystallizer body 1, but only requires adding steam purging pipelines to each feed nozzle body 3. The implementation is simple, the modification cost is low, and it is conducive to promotion and application on existing units.

[0034] V. Nitrogen Replacement and System Reset Stage Shut down the pulse steam supply equipment, then sequentially close the manual shut-off valve 51 and the spring-loaded check valve 52, reset the blind plate isolation device 53, and re-tighten it using the double-bolt fastening structure 421 to restore the physical isolation state. Cut off the steam supply, open the one-way inlet valve 72 on the nitrogen branch 71, and introduce nitrogen to replace the steam branch pipe 42 and the interior of the crystallizer body 1. Continue to replace the oxygen content in the system until it is ≤0.5 vol%, meeting the ExdⅡCT4 explosion-proof safety requirements. Close the one-way inlet valve 72 to stop the nitrogen supply, and the differential pressure transmitter 61 resumes normal monitoring. The crystallizer body 1 returns to continuous production.

[0035] All electrical components appearing in this application are electrically connected to the controller and 220V AC mains power. The controller is a conventional and known device that can control the differential pressure transmitter 61, servo motor 821, pressure sensor 92, and processor 93. The signal interaction of each component adopts the PLC control protocol commonly used in industrial equipment, which is common knowledge to those skilled in the art and can be implemented without further detailed description. The control logic and signal interaction method are existing technologies and will not be described in detail. All standard parts used in this application can be purchased from the market. The specific connection methods of each part are all conventional methods such as riveting and welding, which are mature in the prior art. The standard parts are all conventional models in the prior art, and the circuit connection adopts conventional connection methods in the prior art.

[0036] It should be noted that the above electrical components are all existing technology products. They are selected, installed and debugged by those skilled in the art according to the needs of use to ensure that all electrical appliances can work normally. The components are all general standard parts or parts known to those skilled in the art. Their structure and principle can be known by those skilled in the art through technical manuals or conventional experimental methods. No specific restrictions are made here.

[0037] It should be noted that in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0038] 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. A purging device for clogging the feed nozzle of a caprolactam crystallizer, comprising a crystallizer body (1), a cylinder cover (11) fixedly installed on the top of the crystallizer body (1), an exhaust pipe (12) fixedly installed on the cylinder cover (11), a one-way exhaust valve (13) provided on the exhaust pipe (12), the exhaust pipe (12) being connected to the input end of a waste gas collection device, the crystallizer body (1) being fixedly installed on a frame (2), and two sets of feed nozzle bodies (3) with their discharge ends fixedly installed on the inner circumference of the crystallizer body (1), the feed ends of the two sets of feed nozzle bodies (3) being connected to the output ends of a gaseous ammonia and a re-drained liquid supply device respectively through feed pipes (31), and a feed valve (32) provided on the feed pipe (31), characterized in that: The crystallizer body (1) is provided with a redundant steam supply assembly (4) on its exterior. The redundant steam supply assembly (4) includes two steam distribution main pipes (41). The steam distribution main pipes (41) are located on the outer periphery of the crystallizer body (1). The outlet end of each steam distribution main pipe (41) is fixedly connected to multiple steam branch pipes (42). The ends of the multiple steam branch pipes (42) are fixedly connected to the inlet end of the corresponding feed nozzle body (3). The inlet end of the steam distribution main pipe (41) is connected to the output end of the pulse steam supply equipment through the main pipe (43). A three-level safety protection assembly (5) is also provided outside the crystallizer body (1).

2. The purging device for clogging the feed nozzle of a caprolactam crystallizer according to claim 1, characterized in that: The three-level safety protection components (5) are arranged sequentially along the steam flow direction. The three-level safety protection components (5) include a manual shut-off valve (51), which is fixedly installed on the main pipeline (43).

3. The purging device for clogging the feed nozzle of a caprolactam crystallizer according to claim 2, characterized in that: The main steam distribution pipe (41) is provided with multiple sets of spring-loaded check valves (52), and two adjacent spring-loaded check valves (52) are mirror images of each other outside a single steam branch pipe (42). A blind plate isolation device (53) is fixedly installed on the steam branch pipe (42) by a double bolt fastening structure (421).

4. The purging device for clogging the feed nozzle of a caprolactam crystallizer according to claim 1, characterized in that: A differential pressure transmitter (61) is fixedly installed on the steam branch pipe (42), and the detection end of the differential pressure transmitter (61) is sealed and connected to the inner wall of the steam branch pipe (42).

5. The purging device for clogging the feed nozzle of a caprolactam crystallizer according to claim 1, characterized in that: A nitrogen replacement assembly (7) is provided on the steam branch pipe (42). The nitrogen replacement assembly (7) includes a nitrogen branch (71). The nitrogen branch (71) is welded and fixed to the steam branch pipe (42). A one-way air inlet valve (72) is provided on the nitrogen branch (71). The nitrogen branch (71) is connected to an external nitrogen source.

6. The purging device for clogging the feed nozzle of a caprolactam crystallizer according to claim 1, characterized in that: The main steam distribution pipe (41), steam branch pipe (42) and main pipeline (43) are all made of 316L stainless steel.

7. The purging device for clogging the feed nozzle of a caprolactam crystallizer according to claim 1, characterized in that: An auxiliary component (8) is provided on the crystallizer body (1). The auxiliary component (8) includes a rotating shaft (81). The rotating shaft (81) is rotatably mounted inside the center of the bottom end of the crystallizer body (1) through a sealed bearing. A servo motor (821) is provided at the bottom end of the crystallizer body (1). A drive gear (822) is fixedly mounted at the output end of the servo motor (821). A driven gear (823) is fixedly mounted at the bottom end of the rotating shaft (81). The drive gear (822) meshes with the driven gear (823). The rotating shaft (822) 81) A connector (83) is fixedly installed on the top. Two mirror-arranged stirring rods (84) are fixedly installed on the connector (83). A stirring plate (85) is fixedly installed on the stirring rods (84). A stirring paddle (86) is fixedly installed on the outside of the rotating shaft (81). The stirring paddle (86) is located inside the crystallizer body (1). A connecting rod (87) is also fixedly installed on the connector (83). A scraper (88) is fixedly installed on the connecting rod (87). The scraper (88) slides against the arc-shaped inner wall of the crystallizer body (1).

8. The purging device for clogging the feed nozzle of a caprolactam crystallizer according to claim 7, characterized in that: A monitoring component (9) is provided on the rotating shaft (81). The monitoring component (9) includes a bend (91). The bend (91) is fixedly installed at one end of the connector (83). A pressure sensor (92) is fixedly installed inside the bend (91) away from the connector (83). A processor (93) is fixedly installed outside the bend (91) near the connector (83). The inside of the bend (91) is hollow and used for wiring.

9. The purging device for clogging the feed nozzle of a caprolactam crystallizer according to claim 1, characterized in that: The crystallizer body (1) is provided with a feeding mechanism (10) for discharging material at the bottom output end.

10. A purging method for clogging the feed nozzle of a caprolactam crystallizer, employing the purging device according to any one of claims 1-6, characterized in that, Includes the following steps: S1. System status confirmation and blockage monitoring: Before purging, confirm the system pressure and temperature, and monitor the pressure drop of the steam branch pipe (42) in real time through the differential pressure transmitter (61) to determine whether the feed nozzle body (3) is blocked. S2. Open the steam flow pipeline, open the manual shut-off valve (51) and the spring-loaded check valve (52), and open the corresponding blind plate isolation device (53) to open the steam flow pipeline. S3. Start the pulse steam supply. Start the pulse steam supply equipment. Steam is delivered to the corresponding steam distribution main pipe (41) through the main pipe (43) to establish the purging gas source. S4. Pulse purging and unblocking: Steam is blown in a direction through the steam branch pipe (42) to the blocked feed nozzle body (3) to complete the purging and unblocking of the feed nozzle body (3) in a pulse steam supply mode. S5. Nitrogen replacement and system reset: After purging, shut off the steam supply, open the one-way inlet valve (72) on the nitrogen branch (71), replace the inside of the crystallizer body (1) with nitrogen, and close the one-way inlet valve (72) after the replacement meets the standard, and reset the blind plate isolation device (53).

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