A device and method for recovering low-pressure steam from a nitrotoluene distillation tower

Abstract

The invention relates to the technical field of waste heat recovery equipment at the top of a nitrotoluene distillation tower, and in particular to a device and method for recovering low-pressure steam from a nitrotoluene distillation tower. In a nitrotoluene separation and crystallization process, a steam generator is added to the top of an original ortho-tower, and a radiation tube bundle is heated by discharging high-boiling steam from the top of the tower to generate steam, which is then connected to a crystallization device for a nitrotoluene crystallization process. A narrow airflow passage is opened, and as the air intake of an air inlet changes, a movable part is pushed to slide along the narrow airflow passage for different distances, and a connecting column is pulled to move, so that a movable cylinder wall part penetrates into an arc-shaped chute, and an end part of a corresponding radiation tube bundle facing the air inlet is exposed to a furnace chamber, and at the same time, a second heating tube that penetrates into the arc-shaped chute stops heating, so that the heating efficiency of each radiation tube bundle is maintained stable, so that there is no need to frequently and adaptively adjust the amount of water replenishment in each radiation tube bundle, and the stability of steam discharged from the radiation tube bundle is also improved.

Description

Technical Field

[0001] The invention relates to the technical field of waste heat recovery equipment at the top of a nitrotoluene distillation tower, and in particular to a device and method for recovering low-pressure steam from a nitrotoluene distillation tower. Background Art

[0002] In the existing nitrotoluene separation and crystallization process, mixed nitrotoluene raw materials are usually used for multiple distillation, rectification and crystallization treatments, such as removing light components (water and toluene) by a light removal tower, removing heavy components (dinitrotoluene, etc.) by a heavy removal tower, separating ortho-nitrotoluene by an ortho-toluene tower, crystallizing para-nitrotoluene by a crystallization device, and separating meta-nitrotoluene by a meta-toluene tower. The steam consumption in this process is relatively large. As for how to further save energy and improve efficiency, although in the prior art, for example, a waste heat recovery and utilization device of medium-pressure steam condensate disclosed in Chinese patent document CN201625428U is connected to the top of the distillation tower through a low-pressure steam generator, the heat of the gas phase at the top of the distillation tower is recovered and recycled, however, for the current steam generator, such as a 0.5T cross-flow steam generator disclosed in Chinese patent document CN213453584U, the steam generating device is burned by a combustion device. The device is used for heating, and the steam generating device discharges the steam after steam-water separation from the exhaust device to obtain high-quality steam. The flue gas generated by combustion is condensed by the condensing device and then discharged from the exhaust device. The heating efficiency of the combustion device itself is easy to control and has high stability. When different amounts of steam discharge are required, it is only necessary to control and adjust the combustion device and adjust the amount of water replenishment in the furnace tube accordingly. Moreover, since the discharged steam does not involve the subsequent process, the stability requirement for the steam discharge is not high. If a steam generator is connected to the top of the distillation tower to recover the waste heat from the top of the nitrotoluene distillation tower and reduce the steam consumption in the subsequent process, the waste heat source from the top of the distillation tower is equivalent to a traditional combustion device, and its heating efficiency is not easy to control and has low stability. Therefore, it is necessary to frequently and adaptively adjust the amount of water replenishment in the furnace tube, and therefore the stability of the steam discharge is not high, which is easy to affect the subsequent separation and crystallization process of nitrotoluene. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a device and method for recovering low-pressure steam from a nitrotoluene distillation tower, so as to solve the problem that when the waste heat from the top of the nitrotoluene distillation tower is recovered to generate steam, the waste heat heating efficiency is difficult to control and the stability is not high, so the amount of water replenishment in the furnace tube needs to be frequently adaptively adjusted, and the stability of steam discharge is therefore not high.

[0004] Based on the above purpose, the present invention provides a nitrotoluene distillation tower low-pressure steam recovery device, comprising a steam generator, a plurality of radiation tube bundles are arranged in the furnace chamber of the steam generator, an air inlet for connecting to the gas outlet end of the distillation tower is opened at one end of the furnace chamber of the steam generator, and an air outlet is opened at the other end:

[0005] A narrow air flow passage is provided near the air inlet in the furnace chamber of the steam generator, and a movable part is slidably provided in the narrow air flow passage;

[0006] An outer sleeve is sleeved on the outside of the radiation tube bundle near one end of the air inlet, and the outer sleeve includes a fixed tube wall facing one end of the air outlet, arc-shaped slide grooves are opened on both sides of the fixed tube wall, and a movable tube wall is elastically slidably connected in the arc-shaped slide groove. The fixed tube wall, the arc-shaped slide groove, and the movable tube wall are all designed in an arc shape coaxial with the radiation tube bundle. A first heating tube is provided on the inner wall of the fixed tube wall, and a second heating tube is provided on the inner wall of the movable tube wall. The first heating tube and the second heating tube extend in an axial direction parallel to the radiation tube bundle, and a plurality of them are arranged at intervals along the circumferential direction of the outer side of the radiation tube bundle, so as to heat the radiation tube bundle;

[0007] The outer end of the movable cylinder wall is connected to a connecting column, one end of which penetrates into the narrow airway and is connected to a connecting rope, one end of which is connected to a movable part. As the air intake of the air inlet changes, the movable part slides different distances along the narrow airway and pulls the connecting column to move, so that part of the movable cylinder wall penetrates into the arc-shaped slide groove, and one end of the radiation tube bundle facing the air inlet is exposed to the furnace chamber of the steam generator, and at the same time, the second heating tube inserted into the arc-shaped slide groove stops heating.

[0008] Preferably, inner partitions are provided at the top and bottom of the furnace chamber of the steam generator, respectively, and the narrow airflow passage is provided in the inner partition near the air inlet, and the narrow airflow passage is open at one end facing the air inlet.

[0009] Preferably, a water collecting distributor is provided below the furnace chamber of the steam generator, the bottom end of each radiation tube bundle passes through the inner partition and is connected to the water collecting distributor for distributing incoming water, and a gas collecting tank is provided above the furnace chamber of the steam generator, the top end of each radiation tube bundle passes through the inner partition and is connected to the gas collecting tank.

[0010] Preferably, a plurality of rows of radiation tube bundles are arranged along the ventilation direction in the furnace chamber of the steam generator, and the radiation tube bundles in adjacent rows are arranged crosswise and staggered with each other.

[0011] Preferably, the upper and lower ends of the second heating tube are respectively connected to a push-press switch, the open end of the arc-shaped slide groove is provided with a protrusion, and the key head end of the push-press switch is designed with a spherical end face. When the movable cylinder wall passes through the arc-shaped slide groove, the protrusion presses the push-press switch, so that the push-press switch inserted into the arc-shaped slide groove is in a closed state, and the corresponding second heating tube is in a stopped heating state. When the movable cylinder wall passes out of the arc-shaped slide groove, the protrusion presses the push-press switch, so that the push-press switch passing out of the arc-shaped slide groove is in an open state, and the corresponding second heating tube is in a connected heating state.

[0012] Preferably, a guide wheel is rotatably connected between the connecting column and the movable member in the narrow airway, and the connecting rope is wound around the guide wheel.

[0013] Preferably, the narrow air flow channel is provided with an opening communicating with the furnace chamber of the steam generator, a slide plate is slidably connected to the opening, a wire wheel is rotatably connected to the slide plate, one side of the slide plate is connected to an air outlet, the slide plate is elastically connected to the side end of the narrow air flow channel, and is used to pull the slide plate so that the slide plate is in an initial position of closing the opening until the movable part tightens the connecting rope and drives the slide plate to slide, so that the air outlet is moved to the opening and the air is discharged through the opening.

[0014] Preferably, a standing plate is vertically arranged on the slide plate, two sides of the standing plate extend outwardly and are elastically connected to the inner side wall of the narrow air flow channel, and the air outlet is fixedly connected to the outer side of the standing plate.

[0015] Preferably, a lifting plate is provided at one end of the narrow airway facing the air inlet, and the lifting plate is lifted and lowered to open or close the narrow airway.

[0016] The present invention also provides a method for recovering low-pressure steam from a nitrotoluene distillation tower, comprising the following steps:

[0017] In the nitrotoluene separation crystallization process, a low-pressure steam generator is added to the top of the original ortho-tower, and the high-boiling steam material discharged from the top of the ortho-tower is introduced into the furnace chamber of the steam generator to heat the radiation tube bundle, so that steam is generated in the radiation tube bundle, and the generated steam is collected and connected to the crystallization device for the crystallization process of nitrotoluene;

[0018] Among them, by opening the narrow air flow channel, the movable part is pushed to slide different distances along the narrow air flow channel as the air intake volume of the air inlet changes, and the connecting column is pulled to move, so that the movable cylinder wall part penetrates into the arc-shaped slide groove, and the end part of the corresponding radiation tube bundle facing the air inlet is exposed to the furnace chamber. At the same time, the second heating tube inserted into the arc-shaped slide groove stops heating, so that the heating efficiency of each radiation tube bundle remains stable.

[0019] The invention has the following beneficial effects: in the nitrotoluene separation and crystallization process, a low-pressure steam generator is added to the top of the original ortho-tower, and the high-boiling steam material discharged from the top of the ortho-tower is introduced into the furnace chamber of the steam generator to heat the radiation tube bundle, so that steam is generated in the radiation tube bundle, and the generated steam is collected and connected to the crystallization device for the crystallization process of nitrotoluene; wherein, by opening the narrow flow airway, the movable part is pushed to slide different distances along the narrow flow airway as the air intake of the air inlet changes, and the connecting column is pulled to move, so that the movable cylinder wall part penetrates into the arc chute, and the end part of the corresponding radiation tube bundle facing the air inlet is exposed to the furnace chamber, and at the same time, the second heating tube inserted into the arc chute stops heating, so that the heating efficiency of each radiation tube bundle is maintained stable, so there is no need to frequently and adaptively adjust the amount of water replenishment in each radiation tube bundle, and the stability of the steam discharged from the radiation tube bundle is also improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 It is a schematic diagram of the top view of the structure of the arrangement of the radiation tube bundles of the present invention;

[0023] Figure 3 Schematic diagram of the internal structure of the narrow flow airway of the present invention;

[0024] Figure 4 It is a schematic diagram of the structure of the present invention when the movable cylinder walls on both sides are completely extended and closed;

[0025] Figure 5 It is a schematic cross-sectional structural diagram of the top of the outer sleeve of the present invention;

[0026] Figure 6 It is a front view structural schematic diagram of the radiation tube bundle of the present invention;

[0027] Figure 7 It is a front view structural schematic diagram of the movable part of the present invention slidingly connected in the narrow end of the narrow airway;

[0028] Figure 8 It is a schematic diagram of the structure when the air inlet is opened in the narrow airway of the present invention;

[0029] Fig. 9 It is a schematic diagram of the structure of the outer sleeve corresponding to the narrow airway of the present invention when the air inlet is opened;

[0030] Fig.10 It is a schematic diagram of the structure in the narrow airway when the connecting column of the present invention is opened and moved into position;

[0031] Fig.11 It is a schematic diagram of the structure of the corresponding outer sleeve when the connecting column of the present invention is opened and moved into position;

[0032] Fig.12 It is a schematic diagram of the structure in the narrow airway when the guide wheels on both sides of the present invention are retracted and moved inward;

[0033] Fig.13 For the present invention Fig.12 A magnified schematic diagram of center A.

[0034] The markings in the figure are:

[0035] 1. Steam generator; 100. Water collecting distributor; 200. Gas collecting tank; 2. Furnace chamber; 3. Radiant tube bundle; 31. Thin tube; 4. Air inlet; 5. Air outlet; 6. Narrow air flow channel; 61. Arc-shaped through groove; 7. Movable part; 8. Outer sleeve; 81. Fixed cylinder wall; 810. Arc-shaped slide groove; 82. Movable cylinder wall; 9. First heating tube; 10. Second heating tube; 11. Connecting column; 12. Connecting rope; 13. Inner partition; 14. Push switch; 15. Bump; 16. Wire pulley; 17. Through hole; 18. Slide plate; 19. Exhaust bag; 20. Standing board; 21. Lifting board. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0037] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0038] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7As shown, a nitrotoluene distillation tower low-pressure steam recovery device comprises a steam generator 1, a furnace chamber 2 of the steam generator 1 is provided with a plurality of radiation tube bundles 3, one end of the furnace chamber 2 of the steam generator 1 is provided with an air inlet 4 for docking with the gas outlet end of the distillation tower, and the other end is provided with an air outlet 5, a narrow air flow channel 6 is provided near the air inlet 4 in the furnace chamber 2 of the steam generator 1, a movable part 7 is slidably provided in the narrow air flow channel 6, an outer sleeve 8 is sleeved on the outer side of the radiation tube bundle 3 near one end of the air inlet 4, the outer sleeve 8 comprises a fixed cylinder wall 81 facing one end of the gas outlet 5, arc-shaped slide grooves 810 are provided on both sides of the fixed cylinder wall 81, a movable cylinder wall 82 is elastically slidably connected in the arc-shaped slide groove 810, the fixed cylinder wall 81, the arc-shaped slide groove 810, and the movable cylinder wall 82 are all designed in an arc shape coaxial with the radiation tube bundle 3, and the inner wall of the fixed cylinder wall 81 is provided with a movable part 710. There is a first heating tube 9, and a second heating tube 10 is arranged on the inner wall of the movable cylinder wall 82. The first heating tube 9 and the second heating tube 10 extend in an axial direction parallel to the radiation tube bundle 3, and a plurality of them are arranged at intervals along the outer circumferential direction of the radiation tube bundle 3 for heating the radiation tube bundle 3. The outer end of the movable cylinder wall 82 is connected with a connecting column 11, one end of the connecting column 11 penetrates into the narrow airflow channel 6, and is connected with a connecting rope 12, one end of the connecting rope 12 is connected to the movable part 7, and when the air intake of the air inlet 4 changes, the movable part 7 slides different distances along the narrow airflow channel 6 and pulls the connecting column 11 to move, so that part of the movable cylinder wall 82 penetrates into the arc-shaped slide groove 810, and the end of the radiation tube bundle 3 facing the air inlet 4 is partially exposed to the furnace chamber 2 of the steam generator 1, and at the same time, the second heating tube 10 penetrated into the arc-shaped slide groove 810 stops heating.

[0039] The present invention is directed to the existing nitrotoluene separation and crystallization process, that is, using mixed nitrotoluene raw materials to perform multiple distillation, rectification and crystallization treatments. In particular, a low-pressure steam generator 1 is added to the top of the original ortho-toluene tower. A plurality of radiation tube bundles 3 are arranged in the furnace chamber 2 of the steam generator 1, which are equivalent to traditional furnace tubes. An air inlet 4 for connecting to the gas outlet end of the rectification tower is opened at one end of the furnace chamber 2 of the steam generator 1, and an air outlet 5 is opened at the other end. High-boiling steam materials such as ortho-nitrotoluene discharged from the top of the ortho-toluene tower are introduced into the furnace chamber 2 of the steam generator 1 to heat the radiation tube bundle 3, so that the radiation tube bundle 3 is heated. Steam is generated in the bundle 3, the generated steam is collected and connected to the crystallization device for the crystallization process of para-nitrotoluene. Considering that the light removal tower and the heavy removal tower are substantially distillation towers, the discharge amount is small and insufficient for stable heating and production of steam, while the ortho tower is substantially a rectification tower, and the discharge amount is large, which is sufficient for the steam generator 1 to stably produce steam. The high-boiling steam material flowing out of the gas outlet 5 is further condensed by the condenser, part of which is refluxed to the ortho tower, and part of which is discharged, so as to realize the complete nitrotoluene separation and crystallization process, and the waste heat of the ortho tower is recovered to generate steam for the crystallizer, thereby reducing steam consumption;

[0040] In particular, a narrow air flow passage 6 is provided near the air inlet 4 in the furnace chamber 2 of the steam generator 1, and a movable part 7 is slidably provided in the narrow air flow passage 6. Part of the intake air passes into the narrow air flow passage 6, and the wind pressure of the intake air blows the movable part 7. An outer sleeve 8 is sleeved on the outer side of the radiation tube bundle 3 near one end of the air inlet 4. The outer sleeve 8 includes a fixed tube wall 81 facing one end of the air outlet 5. The fixed tube wall 81 is provided with arc-shaped slide grooves 810 on both sides, and the movable tube wall 8 is elastically slidably connected in the arc-shaped slide groove 810. 2, the fixed cylinder wall 81, the arc-shaped slide groove 810, and the movable cylinder wall 82 are all designed in an arc shape coaxial with the radiation tube bundle 3. A first heating tube 9 is provided on the inner wall of the fixed cylinder wall 81, and a second heating tube 10 is provided on the inner wall of the movable cylinder wall 82. The first heating tube 9 and the second heating tube 10 extend in an axial direction parallel to the radiation tube bundle 3, and a plurality of them are arranged at intervals along the outer circumferential direction of the radiation tube bundle 3. When the movable cylinder walls 82 on both sides completely pass through the arc-shaped slide groove 810, as shown in FIG. Figure 3 , Figure 4As shown, the movable cylinder wall 82 and the fixed cylinder wall 81 on both sides are surrounded to form a cylindrical outer sleeve 8, so as to completely cover the outside of the radiation tube bundle 3, and the corresponding radiation tube bundle 3 is evenly heated by the first heating tube 9 and the second heating tube 10, that is, the radiation tube bundle 3 close to the air inlet 4 is separately radiated and heated, and the radiation tube bundle 3 at the rear end is radiated and heated by the high boiling steam material flowing along the air inlet 4 and the air outlet 5. The outer end of the movable cylinder wall 82 is connected to a connecting column 11, one end of the connecting column 11 penetrates into the narrow air flow channel 6, and is connected to a connecting rope 12, and the connecting rope 12 is One end is connected to the movable part 7. Considering the ortho-tower distillation operation in actual production, although the process temperature is relatively controllable, the ortho-nitrotoluene component of the mixed nitrotoluene raw material and the raw material flow rate and other uncontrollable factors affect the ortho-toluene top discharge temperature, which leads to the fact that the ortho-toluene top discharge temperature is often relatively controllable, but the discharge amount is prone to fluctuation. When the air intake of the air inlet 4 increases, the heating efficiency of each radiation tube bundle 3 will inevitably increase. When the air intake of the air inlet 4 decreases, the heating efficiency of each radiation tube bundle 3 will inevitably decrease. Therefore, it is necessary to frequently and adaptively adjust the amount of water in the furnace tube, that is, the radiation tube bundle 3, and the radiation tube bundle 3 discharges The stability of steam is not high, which can easily affect the crystallization process of p-nitrotoluene in the crystallization device. By opening the narrow airflow channel 6, as the air intake of the air inlet 4 changes, the movable part 7 will inevitably be pushed to slide different distances along the narrow airflow channel 6, and the connecting column 11 will be pulled to move, so that the movable cylinder wall 82 partially penetrates into the arc-shaped chute 810, and the end of the corresponding radiation tube bundle 3 facing the air inlet 4 is partially exposed in the furnace chamber 2. At the same time, the second heating tube 10 inserted into the arc-shaped chute 810 stops heating, so that even if the air intake increases, the air intake first heats the exposed part of the front radiation tube bundle 3. Radiative heat exchange consumes the temperature of the intake air, ensuring that the heating efficiency of the rear end radiation tube bundle 3 is maintained within a relatively stable controllable range, while the exposed portion of the front end radiation tube bundle 3 is heated by the intake air radiation, replacing the radiation heating of the second heating tube 10 inserted into the arc-shaped slide groove 810, and the closed portion of the outer sleeve 8 is heated by the original first heating tube 9 and the second heating tube 10, thereby ensuring that the heating efficiency of the front end radiation tube bundle 3 is maintained within a relatively stable controllable range, so there is no need to frequently adaptively adjust the amount of water replenishment in each radiation tube bundle 3, and the stability of the steam discharged from the radiation tube bundle 3 is also improved.

[0041] Among them, Figure 4 , Figure 5 , Figure 6As shown, the arc-shaped slide grooves 810 located at the top and bottom ends of the fixed cylinder wall 81 are designed to be circular arc-shaped slide grooves adapted to the movable cylinder wall 82, so that the movable cylinder wall 82 can slide stably against the inner wall of the slide groove. The arc-shaped slide groove 810 located in the middle part of the fixed cylinder wall 81 is designed to be expanded for the second heating tube 10 to pass through. The connecting column 11 is located at the outer end of the movable cylinder wall 82 away from the fixed cylinder wall 81, and is used to pull the movable cylinder wall 82 to slide along a circular trajectory. In addition, the outer end of the movable cylinder wall 82 passing through the arc-shaped slide groove 810 can be An elastic component such as an elastic rope is connected, or an elastic component such as a spring is connected between the inner end of the movable tube wall 82 passing through the arc-shaped slide groove 810, or an elastic component such as a spring is connected between the outer end of the movable tube wall 82 passing through the arc-shaped slide groove 810 and the fixed tube wall 81, so as to realize the elastic sliding connection of the movable tube wall 82. When the air inlet 4 is not in the air intake state or the narrow air flow channel 6 is not opened, the movable tube wall 82 is pushed or pulled outward by the elastic component until the outer ends of the movable tube walls 82 on both sides are close to each other. Figure 3 , Figure 4 As shown, the radiation tube bundle 3 is completely enclosed and covered, and the narrow air flow channel 6 is opened, and the air intake amount of the air inlet 4 changes, as shown in FIG. Figure 8 , Fig. 9 As shown, the movable member 7 slides along the narrow air flow channel 6 at different distances and pulls the connecting column 11 to move, so that the movable cylinder wall 82 partially penetrates into the arc-shaped sliding groove 810.

[0042] In addition, if Figure 3 , Figure 8 As shown, an arc-shaped groove 61 is opened on the inner wall of the narrow airway 6 for the connecting column 11 to pass through and move. Even if the narrow airway 6 is connected with the furnace chamber 2 through the arc-shaped groove 61, the movement of the movable part 7 is not affected. More preferably, the inner wall of the narrow airway 6 is designed as a sandwich structure around the arc-shaped groove 61, and the interlayer is padded with an existing conventional high-temperature resistant film. The connecting column 11 passes through and is fixed on the film, and plays a role in closing the arc-shaped groove 61 through the film. As the connecting column 11 moves along the arc-shaped groove 61, the film is driven to fold or stretch, thereby maintaining the closed state of the arc-shaped groove 61.

[0043] In an embodiment of the present invention, Figure 1 , Figure 2 As shown, the top and bottom of the furnace chamber 2 of the steam generator 1 are respectively provided with inner partitions 13, and the narrow airflow channel 6 is provided in the inner partition 13 near the air inlet 4. The narrow airflow channel 6 is open at one end facing the air inlet 4, which is conducive to expanding the air inlet angle. The inner diameter of the narrow end of the narrow airflow channel 6 is designed to match the outer diameter of the movable part 7. Specifically, as shown in FIG. Figure 2 , Figure 7As shown, the movable member 7 can adopt the existing conventional design such as a hollow lightweight sphere, and the narrow end of the narrow airway 6 can be designed in a corresponding cylindrical shape. The movable member 7 slides along the cylindrical narrow end of the narrow airway 6. Optionally, a sliding ball can be provided on the inner side wall of the cylindrical narrow end of the narrow airway 6. When the incoming air enters the narrow airway 6, the movable member 7 is more efficiently pushed to slide against the sliding ball, while reducing air leakage. Even if there is a small amount of air leakage, the narrow airway 6 can be kept in the narrow airway 6. The continuous incoming wind is sufficient to maintain the wind pressure in the narrow airway 6, which is used to push the movable part 7. In addition, the movable tube wall 82 can be made of lightweight materials. Movable balls can be provided at the top and bottom ends of the movable tube wall 82, and the movable balls are abutted against the outer wall of the inner partition 13 to ensure the efficient movement of the movable tube wall 82. The incoming wind will also blow the movable tube wall 82 to promote its movement. By designing the narrow airway 6 and the movable part 7 of appropriate size, it is beneficial to stably pull the connecting column 11 for adjustment.

[0044] In an embodiment of the present invention, Figure 1 As shown, a water collecting distributor 100 is provided below the furnace chamber 2 of the steam generator 1, and the water collecting distributor 100 is externally connected to a water storage cylinder. The bottom end of each radiation tube bundle 3 passes through the inner partition 13 and is connected to the water collecting distributor 100, which is used to distribute water to each radiation tube bundle 3. A gas collecting tank 200 is provided above the furnace chamber 2 of the steam generator 1, and the top end of each radiation tube bundle 3 passes through the inner partition 13 and is connected to the gas collecting tank 200, which is used to collect steam discharged from each radiation tube bundle 3. The collected steam is used to pass into the crystallizer of para-nitrotoluene.

[0045] In an embodiment of the present invention, Figure 1 , Figure 2 As shown, the radiation tube bundles 3 are arranged in multiple rows along the ventilation direction in the furnace chamber 2 of the steam generator 1, and the radiation tube bundles 3 in adjacent rows are arranged in a cross-staggered manner, which is conducive to more efficient flow of intake air through each radiation tube bundle 3 for radiation heating. On the other hand, in the inner partition 13, the radiation tube bundles 3 in adjacent rows are arranged in a cross-staggered manner, which is conducive to the more effective arrangement of the narrow flow channel 6, and the narrow end thereof can be more fully extended to the rear end, which is conducive to the sliding adjustment of the movable part 7, especially the frontmost radiation tube bundle 3 that penetrates into the inner partition 13 is designed as a thin tube 31, which is conducive to the collection of steam on the one hand, and on the other hand, it tries to avoid interference with the air intake of the movable part 7.

[0046] In an embodiment of the present invention, Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6As shown, optionally, the upper and lower ends of the second heating tube 10 can be respectively provided with existing conventional switch components such as proximity switches, distance switch sensors, etc. for controlling the power on and off of the second heating tube 10. For the second heating tube 10 passing through the arc-shaped chute 810, its switch component faces the radiation tube bundle 3, the distance is relatively far, triggering the second heating tube 10 to be powered on, and the second heating tube 10 passing through the arc-shaped chute 810, its switch component faces the arc-shaped chute 810, the distance is relatively close, triggering the second heating tube 10 to be powered off. In another optional manner, the upper and lower ends of the second heating tube 10 are respectively connected with push switches 1 4, a protrusion 15 is provided at the open end of the arc-shaped slide groove 810, wherein, since the arc-shaped slide groove 810 located in the middle part of the fixed cylinder wall 81 is designed to be expanded, the second heating tube 10, the push switch 14, and the protrusion 15 are passed or set, and the key head end of the push switch 14 is designed to be a spherical end surface, and the key head of the push switch 14 is elastically connected to its base, so that the key head of the push switch 14 is in an initial state of popping out, and the protrusion 15 can be designed to be a spike-shaped head end. When the movable cylinder wall 82 penetrates along the arc-shaped slide groove 810, the push switch is pressed by the protrusion 15 until the push switch 14 passes over the protrusion 15 and is completed. The push-press switch 14 is fully inserted into the arc-shaped slide groove 810, so that the push-press switch 14 inserted into the arc-shaped slide groove 810 is in a closed state, and the corresponding second heating tube 10 is in a stopped heating state. When the movable cylinder wall 82 passes through the arc-shaped slide groove 810, the convex block 15 presses the push-press switch 14 until the push-press switch 14 passes over the convex block 15 and completely passes out of the arc-shaped slide groove 810, so that the push-press switch 14 passing out of the arc-shaped slide groove 810 is in an open state, and the corresponding second heating tube 10 is in a connected heating state. Among them, the push-press switch 14 can adopt an existing conventional push-press switch, and the switch connection is triggered when the switch button is fully pressed. When the switch button is fully pressed again, the switch is triggered to disconnect, or a conventional pressure switch or other switch electronic components are provided in the push switch 14. When the push switch 14 reaches the tip of the protrusion 15, the fully pressed push switch 14 triggers the internal pressure switch or other switch electronic components. Each time the push switch 14 is fully pressed, the internal switch components are triggered to connect or disconnect. On the other hand, each time the push switch 14 passes over the tip of the protrusion 15, the switch action is triggered, which helps to avoid the push switch 14 repeatedly jumping sideways to trigger the on-off action when the movable cylinder wall 82 shakes in a small range.

[0047] In an embodiment of the present invention, Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown, a guide wheel 16 is rotatably connected between the connecting column 11 and the movable part 7 in the narrow air channel 6, and the connecting rope 12 is wound around the guide wheel 16, so as to avoid direct contact and friction between the connecting rope 12 and the thin tubes 31 of the radiation tube bundle 3 penetrating into the inner partition 13.

[0048] In an embodiment of the present invention, Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 , Fig.12 , Fig.13 As shown, the narrow air flow passage 6 is provided with a through opening 17 communicating with the furnace chamber 2 of the steam generator 1, a slide plate 18 is slidably connected to the through opening 17, a guide wheel 16 is rotatably connected to the slide plate 18, a gas outlet 19 is connected to one side of the slide plate 18, and the slide plate 18 is elastically connected to the side end of the narrow air flow passage 6 for pulling the slide plate 18, as shown in FIG. Figure 3 , Figure 8 , Fig.10 As shown, the slide plate 18 is in the initial position of the closed opening 17, until the movable member 7 tightens the connecting rope 12, so that the movable cylinder wall 82 completely penetrates into the fixed cylinder wall 81, and the connecting column 11 is opened and moved into place. At this time, if the air intake volume of the air inlet 4 continues to increase, the connecting rope 12 is continued to be pulled by the movable member 7, as shown in FIG. Fig.12 , Fig.13 As shown, the guide wheels 16 and the slide plate 18 on both sides are driven to move inwardly, so that the air outlet tube 19 is moved to the opening 17 and the air is discharged through the opening 17. The air outlet tube 19 can be externally connected with an air outlet pipe, and the air outlet pipe is discharged through the inner partition 13, thereby further adjusting the stability of the steam device.

[0049] Among them, a standing plate 20 is vertically arranged on the slide plate 18, and both sides of the standing plate 20 extend outwardly and are elastically connected to the inner wall of the narrow airway 6. Specifically, the two sides of the standing plate 20 extending outwardly are connected to the inner wall of the narrow airway 6 through existing conventional elastic components such as springs to achieve elastic connection. On the other hand, the air outlet 19 is fixedly connected to the outer side of the standing plate 20 to achieve stable connection.

[0050] In an embodiment of the present invention, Figure 1 , Figure 2 As shown, a lifting plate 21 is provided at one end of the narrow airway 6 facing the air inlet 4 for lifting and lowering to open or close the narrow airway 6. If the movable cylinder wall 82 does not need to move for adaptive adjustment, the lifting plate 21 can be controlled to be lowered to close the narrow airway 6.

[0051] The present invention also provides a method for recovering low-pressure steam from a nitrotoluene distillation tower, comprising the following steps:

[0052] In the nitrotoluene separation and crystallization process, a low-pressure steam generator 1 is added to the top of the original ortho-tower, and the high-boiling steam material discharged from the top of the ortho-tower is passed into the furnace chamber 2 of the steam generator 1 to heat the radiation tube bundle 3, so that steam is generated in the radiation tube bundle 3, and the generated steam is collected and connected to the crystallization device for the crystallization process of nitrotoluene;

[0053] Among them, by opening the narrow air flow channel 6, as the air intake volume of the air inlet 4 changes, the movable part 7 is pushed to slide different distances along the narrow air flow channel 6, and the connecting column 11 is pulled to move, so that the movable cylinder wall 82 partially penetrates into the arc-shaped slide groove 810, and the end of the corresponding radiation tube bundle 3 facing the air inlet 4 is partially exposed to the furnace chamber 2. At the same time, the second heating tube 10 inserted into the arc-shaped slide groove 810 stops heating, so that the heating efficiency of each radiation tube bundle 3 is maintained stable, so there is no need to frequently adaptively adjust the amount of water replenishment in each radiation tube bundle 3, and the stability of steam discharged from the radiation tube bundle 3 is also improved.

[0054] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A nitrotoluene distillation tower low-pressure steam recovery device, comprising a steam generator (1), a furnace chamber (2) of the steam generator (1) having a plurality of radiation tube bundles (3) arranged therein, a furnace chamber (2) of the steam generator (1) having an air inlet (4) for connecting to an air outlet end of a distillation tower at one end, and an air outlet (5) at the other end, characterized in that: A narrow air flow passage (6) is provided in the furnace chamber (2) near the air inlet (4), and a movable part (7) is slidably provided in the narrow air flow passage (6); An outer sleeve (8) is sleeved on the outer side of the radiation tube bundle (3) near one end of the air inlet (4), and the outer sleeve (8) includes a fixed tube wall (81) facing one end of the air outlet (5). Arc-shaped slide grooves (810) are opened on both sides of the fixed tube wall (81), and a movable tube wall (82) is elastically slidably connected in the arc-shaped slide groove (810). The fixed tube wall (81), the arc-shaped slide groove (810), and the movable tube wall (82) are all designed in the shape of an arc coaxial with the radiation tube bundle (3). A first heating tube (9) is provided on the inner wall of the fixed tube wall (81), and a second heating tube (10) is provided on the inner wall of the movable tube wall (82). The first heating tube (9) and the second heating tube (10) extend in a direction parallel to the axial direction of the radiation tube bundle (3), and a plurality of them are arranged at intervals along the circumferential direction of the outer side of the radiation tube bundle (3); The outer end of the movable tube wall (82) is connected to a connecting column (11), one end of the connecting column (11) penetrates into the narrow airflow channel (6) and is connected to a connecting rope (12), one end of the connecting rope (12) is connected to the movable part (7), and as the air intake of the air inlet (4) changes, the movable part (7) slides along the narrow airflow channel (6) by different distances and pulls the connecting column (11) to move, so that the movable tube wall (82) partially penetrates into the arc-shaped slide groove (810), and one end of the radiation tube bundle (3) facing the air inlet (4) is partially exposed to the furnace chamber (2) of the steam generator (1), and at the same time, the second heating tube (10) that penetrates into the arc-shaped slide groove (810) stops heating; The narrow air channel (6) is designed to be open at one end facing the air inlet (4), and the inner diameter of the narrow end of the narrow air channel (6) is designed to match the outer diameter of the movable part (7).

2. A nitrotoluene distillation tower low-pressure steam recovery device according to claim 1, characterized in that: The top and bottom ends of the furnace chamber (2) of the steam generator (1) are respectively provided with inner partitions (13), and the narrow air flow channel (6) is arranged in the inner partition (13) near the air inlet (4).

3. A nitrotoluene distillation tower low-pressure steam recovery device according to claim 2, characterized in that: A water collecting distributor (100) is provided below the furnace chamber (2) of the steam generator (1), and the bottom end of each radiation tube bundle (3) passes through the inner partition (13) and is connected to the water collecting distributor (100) for distributing incoming water. An air collecting tank (200) is provided above the furnace chamber (2) of the steam generator (1), and the top end of each radiation tube bundle (3) passes through the inner partition (13) and is connected to the air collecting tank (200).

4. A nitrotoluene distillation tower low-pressure steam recovery device according to claim 1, characterized in that: The radiation tube bundles (3) are arranged in a plurality of rows along the ventilation direction in the furnace chamber (2) of the steam generator (1), and the radiation tube bundles (3) in adjacent rows are arranged in a staggered manner.

5. The low-pressure steam recovery device of a nitrotoluene distillation tower according to claim 1, characterized in that: The upper and lower ends of the second heating tube (10) are respectively connected to a push switch (14); the open end of the arc-shaped slide groove (810) is provided with a protrusion (15); the key head end of the push switch (14) is designed as a spherical end surface; when the movable tube wall (82) passes through the arc-shaped slide groove (810), the protrusion (15) presses the push switch (14) so ​​that the push switch (14) passing through the arc-shaped slide groove (810) is in a closed state, and the corresponding second heating tube (10) is in a stopped heating state; when the movable tube wall (82) passes through the arc-shaped slide groove (810), the protrusion (15) presses the push switch (14) so ​​that the push switch (14) passing through the arc-shaped slide groove (810) is in an open state, and the corresponding second heating tube (10) is in a connected heating state.

6. The low-pressure steam recovery device of a nitrotoluene distillation tower according to claim 1, characterized in that: A guide wheel (16) is rotatably connected between the connecting column (11) and the movable part (7) in the narrow air flow passage (6), and the connecting rope (12) is wound around the guide wheel (16).

7. A nitrotoluene distillation tower low-pressure steam recovery device according to claim 6, characterized in that: The narrow air flow passage (6) is provided with an opening (17) which is in communication with the furnace chamber (2) of the steam generator (1); a slide plate (18) is slidably connected to the opening (17); the guide wheel (16) is rotatably connected to the slide plate (18); one side of the slide plate (18) is connected to an air outlet (19); the slide plate (18) is elastically connected to the side end of the narrow air flow passage (6) and is used to pull the slide plate (18) so that the slide plate (18) is in an initial position closing the opening (17) until the movable part (7) tightens the connecting rope (12) to drive the slide plate (18) to slide, so that the air outlet (19) moves to the opening (17) and is connected to the air outlet through the opening (17).

8. The low-pressure steam recovery device of a nitrotoluene distillation tower according to claim 7, characterized in that: A standing plate (20) is vertically arranged on the slide plate (18), and the two sides of the standing plate (20) extend outwards and are elastically connected to the inner wall of the narrow air flow channel (6), and the air outlet tube (19) is fixedly connected to the outer side of the standing plate (20).

9. The low-pressure steam recovery device of a nitrotoluene distillation tower according to claim 1, characterized in that: A lifting plate (21) is provided at one end of the narrow airflow passage (6) facing the air inlet (4), and the narrow airflow passage (6) is opened or closed by lifting the lifting plate (21).

10. A method for recovering low-pressure steam from a nitrotoluene distillation tower, the method adopting the device for recovering low-pressure steam from a nitrotoluene distillation tower as claimed in any one of claims 1 to 9 for recovery, characterized in that: The following steps are involved: In the nitrotoluene separation and crystallization process, a low-pressure steam generator (1) is added to the top of the original ortho-tower, and the high-boiling steam material discharged from the top of the ortho-tower is introduced into the furnace chamber (2) of the steam generator (1) to heat the radiation tube bundle (3), so that steam is generated in the radiation tube bundle (3), and the generated steam is collected and connected to a crystallization device for the crystallization process of nitrotoluene; By opening the narrow air flow channel (6), the movable part (7) is pushed to slide different distances along the narrow air flow channel (6) as the air intake volume of the air inlet (4) changes, and the connecting column (11) is pulled to move, so that the movable cylinder wall (82) partially penetrates into the arc-shaped slide groove (810), and the end portion of the corresponding radiation tube bundle (3) facing the air inlet (4) is exposed to the furnace chamber (2), and at the same time, the second heating tube (10) inserted into the arc-shaped slide groove (810) stops heating, so that the heating efficiency of each radiation tube bundle (3) remains stable.

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