Device for cleaning paraformaldehyde in absorption tower

Abstract

The utility model relates to the technical field of cleaning absorption tower paraformaldehyde, in particular to a device for cleaning absorption tower paraformaldehyde, which comprises an absorption tower, a preheater and an alkali liquor tank, a stuffing box section is arranged in the absorption tower, a tower tray is fixedly arranged at the bottom of the stuffing box section, a liquid distributor is arranged on the upper portion of the stuffing box section, and the absorption tower is communicated with a first desalted water pipeline. The absorption tower is communicated with a formaldehyde liquid pipeline, a circulating pipeline is communicated between the formaldehyde liquid pipeline and the first desalted water pipeline, the preheater is communicated with a boiler water pipeline, a high-temperature boiler water pipeline is communicated between the preheater and the formaldehyde liquid pipeline between the absorption tower and the circulating pipeline, and an alkali liquid pipeline is communicated between the alkali liquid tank and the circulating pipeline. The paraformaldehyde cleaning device is reasonable and compact in structure and convenient to use, can quickly clean paraformaldehyde in the absorption tower, prolongs the safe production operation time of the absorption tower, improves the economic production benefits of enterprises, and has the characteristics of safety, labor saving, simplicity, convenience and high efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of polyoxymethylene for cleaning an absorption tower, and is a device for cleaning polyoxymethylene in an absorption tower. Background Technique

[0002] A certain chemical enterprise uses the iron-molybdenum process to produce formaldehyde products. First, methanol is partially oxidized to obtain a formaldehyde mixed gas, and the formaldehyde mixed gas then enters the absorption tower. At the same time, a desalted water circulation is established in each packing box in the absorption tower. The formaldehyde mixed gas is cooled and absorbed by the desalted water through multiple packing box sections in the absorption tower to produce qualified formaldehyde liquid.

[0003] During the long-term operation of the absorption tower, high-concentration formaldehyde liquid (51% to 53%) will condense and accumulate polyoxymethylene on the bottom tower tray and packing box of the absorption tower, increasing the load on the bottom tower tray, easily causing the tower tray to deform, and also easily blocking the packing box. In severe cases, the tower tray will fall off, and the packing will accumulate at the bottom of the absorption tower, ultimately resulting in the inability to normally extract formaldehyde products, and the production operation of the absorption tower can only be suspended for maintenance.

[0004] Currently, after the absorption tower has been in production operation for a period of time, it is necessary to stop the absorption tower for maintenance and cleaning. The cleaning method is to use the original production process pipeline system of the absorption tower and use desalted water to clean the bottom packing box and tower tray of the absorption tower. However, this cleaning method takes a long time and the cleaning is not thorough, ultimately resulting in a delay in the start-up operation of the absorption tower, bringing great economic losses to the enterprise. Therefore, the long cleaning time and incomplete cleaning of the absorption tower have become a technical problem that the enterprise has long been unable to overcome. Summary of the Invention

[0005] The utility model provides a device for cleaning polyoxymethylene in an absorption tower, which overcomes the above-mentioned deficiencies of the prior art and can effectively solve the problems of long cleaning time and incomplete cleaning existing in the existing cleaning of polyoxymethylene in an absorption tower.

[0006] The technical solution of the utility model is realized by the following measures: A device for cleaning polyoxymethylene in an absorption tower includes an absorption tower, a preheater, and an alkali liquid tank. A packing box section is arranged in the absorption tower. A tower tray is fixedly arranged at the bottom of the packing box section, and a liquid distributor is arranged above the packing box section. The lower liquid inlet of the absorption tower is fixedly communicated with a first desalted water pipeline, and the liquid outlet of the first desalted water pipeline is arranged above the liquid distributor. The bottom liquid outlet of the absorption tower is fixedly communicated with a formaldehyde liquid pipeline. A circulation pipeline is fixedly communicated between the formaldehyde liquid pipeline and the first desalted water pipeline. The lower liquid inlet of the preheater is fixedly communicated with a boiler water pipeline. A high-temperature boiler water pipeline is fixedly communicated between the upper liquid outlet of the preheater and the formaldehyde liquid pipeline between the bottom liquid outlet of the absorption tower and the circulation pipeline. An alkali liquid pipeline is fixedly communicated between the lower liquid outlet of the alkali liquid tank and the circulation pipeline.

[0007] The following are further optimizations and / or improvements to the above-mentioned utility model technical solution:

[0008] The inner cavity of the above-mentioned preheater includes a tube side and a shell side. The steam inlet pipe at the top of the preheater is fixedly connected to a steam inlet pipeline, and the steam outlet at the bottom of the preheater is fixedly connected to a steam discharge pipeline.

[0009] The upper liquid inlet of the above-mentioned absorption tower is fixedly connected to a second desalination water pipeline.

[0010] The lower gas inlet of the above-mentioned absorption tower is fixedly connected to a first formaldehyde gas pipeline, and the outlet of the first formaldehyde gas pipeline is arranged below the tray.

[0011] A second formaldehyde gas pipeline is fixedly connected between the gas outlet at the top of the above-mentioned absorption tower and the first formaldehyde gas pipeline.

[0012] A remote liquid level gauge is fixedly arranged on the absorption tower between the above-mentioned liquid distributor and the tray.

[0013] A standby pipeline is fixedly connected between the formaldehyde liquid pipeline, the alkali liquid pipeline, and the first desalination water pipeline in the circulation pipeline between the liquid outlet at the bottom of the above-mentioned absorption tower and the high-temperature boiler water pipeline. Circulation pumps are fixedly installed on the standby pipeline, the formaldehyde liquid pipeline between the standby pipeline and the high-temperature boiler water pipeline, the high-temperature boiler water pipeline, and the alkali liquid pipeline.

[0014] On the formaldehyde liquid pipeline between the above-mentioned circulation pipeline and the outlet of the formaldehyde liquid pipeline, a first solenoid valve and a mass flowmeter are fixedly installed in sequence along the medium flow direction. A second solenoid valve is fixedly installed on the first desalination water pipeline between the inlet of the first desalination water pipeline and the circulation pipeline. A third solenoid valve is fixedly installed on the formaldehyde liquid pipeline between the circulation pump on the formaldehyde liquid pipeline and the high-temperature boiler water pipeline.

[0015] A fourth solenoid valve is fixedly installed on the high-temperature boiler water pipeline at the outlet of the circulation pump on the high-temperature boiler water pipeline. A fifth solenoid valve is fixedly installed on the alkali liquid pipeline at the outlet of the circulation pump on the alkali liquid pipeline. A sixth solenoid valve is fixedly installed on the standby pipeline at the outlet of the circulation pump on the standby pipeline. A seventh solenoid valve is fixedly installed on the circulation pipeline between the first desalination water pipeline and the standby pipeline. An eighth solenoid valve is fixedly installed on the circulation pipeline between the alkali liquid pipeline and the formaldehyde liquid pipeline.

[0016] The above-mentioned device further includes a controller, and the remote liquid level gauge, circulation pump, first solenoid valve, second solenoid valve, third solenoid valve, fourth solenoid valve, fifth solenoid valve, sixth solenoid valve, seventh solenoid valve, eighth solenoid valve, and mass flowmeter are all electrically connected to the controller.

[0017] The structure of the utility model is reasonable and compact, and it is convenient to use. It preheats and raises the temperature of boiler water and then inputs it into the absorption tower, and then inputs the alkali solution into the absorption tower. The high-temperature alkali solution has a good dissolving effect on the paraformaldehyde condensed in the tray and the stuffing box, improving the cleaning efficiency of the absorption tower, shortening the shutdown maintenance time of the absorption tower, and improving the economic production efficiency of the enterprise. It has the characteristics of safety, labor saving, simplicity and high efficiency. Brief Description of the Drawings

[0018] Appendix Figure 1 is a schematic process flow diagram of the utility model.

[0019] Appendix Figure 1 The codes in are respectively: 1 is the absorption tower, 2 is the preheater, 3 is the alkali solution tank, 4 is the tray, 5 is the liquid distributor, 6 is the formaldehyde liquid pipeline, 7 is the first desalinated water pipeline, 8 is the circulation pipeline, 9 is the boiler water pipeline, 10 is the high-temperature boiler water pipeline, 11 is the alkali solution pipeline, 12 is the steam inlet pipeline, 13 is the steam discharge pipeline, 14 is the second desalinated water pipeline, 15 is the first formaldehyde gas pipeline, 16 is the second formaldehyde gas pipeline, 17 is the remote transmission liquid level gauge, 18 is the standby pipeline, 19 is the circulation pump, 20 is the first solenoid valve, 21 is the second solenoid valve, 22 is the third solenoid valve, 23 is the fourth solenoid valve, 24 is the fifth solenoid valve, 25 is the sixth solenoid valve, 26 is the seventh solenoid valve, 27 is the eighth solenoid valve, 28 is the tube side, 29 is the shell side, 30 is the mass flowmeter, 31 is the stuffing box section. Detailed Embodiment

[0020] The utility model is not limited by the following embodiments, and the specific implementation manners can be determined according to the technical solution of the utility model and the actual situation.

[0021] In the utility model, unless otherwise specified, the equipment and devices used are the existing well-known and commonly used equipment and devices in the art.

[0022] In the utility model, for the convenience of description, the description of the relative position relationship of each component is carried out according to the layout mode of the attached drawings of the specification. Figure 1 For example, the position relationships such as front, rear, upper, lower, left and right are determined according to the layout direction of the attached drawings of the specification. Figure 1 of the specification.

[0023] The following further describes the utility model in conjunction with the embodiments and the drawings:

[0024] Embodiment 1: As shown in the appendix Figure 1As shown in the figure, the device for cleaning and absorbing paraformaldehyde in the absorption tower includes an absorption tower 1, a preheater 2, and an alkali liquor tank 3. A stuffing box section 31 is arranged inside the absorption tower 1. A tray 4 is fixedly arranged at the bottom of the stuffing box section 31. A liquid distributor 5 is arranged above the stuffing box section. The lower liquid inlet of the absorption tower 1 is fixedly communicated with a first desalinated water pipeline 7. The liquid outlet of the first desalinated water pipeline 7 is arranged above the liquid distributor 5. The bottom liquid outlet of the absorption tower 1 is fixedly communicated with a formaldehyde liquid pipeline 6. A circulation pipeline 8 is fixedly communicated between the formaldehyde liquid pipeline 6 and the first desalinated water pipeline 7. The lower liquid inlet of the preheater 2 is fixedly communicated with a boiler water pipeline 9. A high-temperature boiler water pipeline 10 is fixedly communicated between the upper liquid outlet of the preheater 2 and the formaldehyde liquid pipeline 6 between the bottom liquid outlet of the absorption tower 1 and the circulation pipeline 8. An alkali liquor pipeline 11 is fixedly communicated between the lower liquid outlet of the alkali liquor tank 3 and the circulation pipeline 8.

[0025] As required, the preheater 2 is a shell and tube heat exchanger.

[0026] As required, the tray 4 can play a role in fixing and supporting the stuffing box section 31. The liquid distributor 5 can make the liquid uniformly penetrate into the stuffing box section 31. The stuffing box section 31 is filled with iron-molybdenum catalyst. One or more layers of stuffing box sections 31 can be arranged inside the absorption tower 1 as required. A tray 4 can be fixedly arranged at the lower part of each stuffing box section 31. A liquid distributor 5 can be arranged above each stuffing box section 31. A shunt pipeline of the first desalinated water pipeline 7 can also be arranged according to actual needs. The present invention can clean each stuffing box section 31 and the tray 4 inside the absorption tower 1.

[0027] As required, the device for cleaning and absorbing paraformaldehyde can be further optimized and / or improved:

[0028] Example 2: The difference from Example 1 is that as shown in the appendix Figure 1 As shown in the figure, the inner cavity of the preheater 2 includes a tube side 28 and a shell side 29. The top air inlet of the preheater 2 is fixedly communicated with a steam inlet pipeline 12. The bottom air outlet of the preheater 2 is fixedly communicated with a steam discharge pipeline 13.

[0029] As required, the steam at the top inside the preheater 2 enters the tube side 28 and then enters the bottom of the preheater 2. The steam at the bottom of the preheater 2 is discharged to the downstream process system through the steam discharge pipeline 13.

[0030] Example 3: The difference from Examples 1 to 2 is that as shown in the appendix Figure 1 As shown in the figure, the upper liquid inlet of the absorption tower 1 is fixedly communicated with a second desalinated water pipeline 14.

[0031] Example 4: The difference from Examples 1 to 3 is that as shown in the appendix Figure 1 As shown in the figure, the lower air inlet of the absorption tower 1 is fixedly communicated with a first formaldehyde gas pipeline 15. The air outlet of the first formaldehyde gas pipeline 15 is arranged below the tray 4.

[0032] Example 5: The difference from Examples 1 to 4 is that, as shown in the appendix, Figure 1 a second formaldehyde gas pipeline 16 is fixedly connected between the gas outlet at the top of the absorption tower 1 and the first formaldehyde gas pipeline 15.

[0033] Example 6: The difference from Examples 1 to 5 is that, as shown in the appendix, Figure 1 a remote liquid level gauge 17 is fixedly arranged on the absorption tower 1 between the liquid distributor 5 and the tray 4.

[0034] Example 7: The difference from Examples 1 to 6 is that, as shown in the appendix, Figure 1 a spare pipeline 18 is fixedly connected between the liquid outlet at the bottom of the absorption tower 1 and the formaldehyde liquid pipeline 6 between the high-temperature boiler water pipeline 10, the alkali liquid pipeline 8 and the first desalinated water pipeline 7, and circulating pumps 19 are fixedly installed on the spare pipeline 18, the formaldehyde liquid pipeline 6 between the spare pipeline 18 and the high-temperature boiler water pipeline 10, the high-temperature boiler water pipeline 10, and the alkali liquid pipeline 11.

[0035] As needed, when the liquid outlet at the bottom of the absorption tower 1 causes an excessive load on the formaldehyde liquid pipeline 6 and the circulating pump 19 on the formaldehyde liquid pipeline 6, the spare pipeline 18 can be used for diversion, and the circulating pump 19 on the spare pipeline 18 provides the circulating power to reduce the load on the formaldehyde liquid pipeline 6 and the circulating pump 19 on the formaldehyde liquid pipeline 6.

[0036] Example 8: The difference from Examples 1 to 7 is that, as shown in the appendix, Figure 1 a first solenoid valve 20 and a mass flowmeter 30 are fixedly installed on the formaldehyde liquid pipeline 6 between the circulating pipeline 8 and the outlet of the formaldehyde liquid pipeline 6 in the direction of the medium flow in sequence, a second solenoid valve 21 is fixedly installed on the first desalinated water pipeline 7 between the inlet of the first desalinated water pipeline 7 and the circulating pipeline 8, and a third solenoid valve 22 is fixedly installed on the formaldehyde liquid pipeline 6 between the circulating pump 19 on the formaldehyde liquid pipeline 6 and the high-temperature boiler water pipeline 10.

[0037] As needed, the model of the mass flowmeter 30 is 8E3B50-NDDBABDFADSAAASHA1+AKZ1, which can perform on-line mass monitoring of the medium in the formaldehyde liquid pipeline 6.

[0038] Example 9: The difference from Examples 1 to 8 is that, as shown in the appendix, Figure 1As shown in the figure, a fourth solenoid valve 23 is fixedly installed on the high-temperature boiler water pipeline 10 at the outlet of the circulation pump 19 on the high-temperature boiler water pipeline 10. A fifth solenoid valve 24 is fixedly installed on the lye pipeline 11 at the outlet of the circulation pump 19 on the lye pipeline 11. A sixth solenoid valve 25 is fixedly installed on the standby pipeline 18 at the outlet of the circulation pump 19 on the standby pipeline 18. A seventh solenoid valve 26 is fixedly installed on the circulation pipeline 8 between the first desalinated water pipeline 7 and the standby pipeline 18. An eighth solenoid valve 27 is fixedly installed on the circulation pipeline 8 between the lye pipeline 11 and the formaldehyde solution pipeline 6.

[0039] Embodiment 10: The difference from Embodiments 1 to 9 is that as shown in the appendix Figure 1 As shown in the figure, the device further includes a controller, and the remote liquid level gauge 17, circulation pump 19, first solenoid valve 20, second solenoid valve 21, third solenoid valve 22, fourth solenoid valve 23, fifth solenoid valve 24, sixth solenoid valve 25, seventh solenoid valve 26, eighth solenoid valve 27, and mass flowmeter 30 are all electrically connected to the controller.

[0040] As needed, on each pipeline and equipment of the anti-lag pretreatment device for on-line gas analysis, conventional valves, thermometers, pressure gauges, etc. well-known and commonly used in the art can also be provided according to production needs. The controller is a DCS controller, and the model of the DCS controller can be the Emerson Deltav controller.

[0041] The above technical features constitute the embodiments of the present utility model, which have strong adaptability and implementation effects. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

[0042] Usage process of the embodiment of the utility model: First, close the first solenoid valve 20, the second solenoid valve 21, the third solenoid valve 22, the fifth solenoid valve 24, and the sixth solenoid valve 25 respectively. The boiler water enters the shell side 29 from the lower part of the preheater 2 through the boiler water pipeline 9, and the steam enters the tube side 28 from the top of the preheater 2 through the steam inlet pipeline 12. The steam in the tube side 28 preheats and heats up the boiler water in the shell side 29. After heat exchange, the steam enters the downstream process system through the steam discharge pipeline 13. Then, the heated boiler water sequentially passes through the high-temperature boiler water pipeline 10, the formaldehyde liquid pipeline 6, the circulation pipeline 8, and the first desalinated water pipeline 7 to enter the liquid distributor 5 in the absorption tower 1. The high-temperature boiler water uniformly flows into the packing section 31 and the tray 4 through the liquid distributor 5. Then, close the fourth solenoid valve 23. The lye in the lye tank 3 sequentially passes through the lye pipeline 11, the circulation pipeline 8, and the first desalinated water pipeline 7 to enter the liquid distributor 5 in the absorption tower 1. The lye uniformly flows into the packing section 31 and the tray 4 through the liquid distributor 5. When the remote liquid level gauge 17 shows that the cleaning process liquid level value is reached, stop inputting lye into the absorption tower 1. The lye and the high-temperature boiler water at the bottom of the absorption tower 1 are mixed to soak and clean the packing section 31 and the tray 4. Finally, after the soaking cleaning time, the cleaning liquid is discharged through the formaldehyde liquid pipeline 6 into the downstream waste liquid treatment system.

[0043] According to needs, the usage process of the production operation of the absorption tower 1: First, close the second solenoid valve 21, the fourth solenoid valve 23, the fifth solenoid valve 24, and the seventh solenoid valve 26 respectively. The desalinated water enters the absorption tower 1 through the second desalinated water pipeline 14. Then, the formaldehyde mixed gas enters the absorption tower 1 through the first formaldehyde gas pipeline 15. At this time, under the catalytic action of the packing section 31 in the absorption tower 1, the formaldehyde in the formaldehyde mixed gas from bottom to top is cooled and absorbed by the desalinated water to obtain the formaldehyde absorption liquid. At the same time, the unabsorbed formaldehyde mixed gas at the top of the absorption tower 1 returns to the first formaldehyde gas pipeline 15 through the second formaldehyde gas pipeline 16 and enters the absorption tower 1 again for cooling and absorption. Finally, the formaldehyde absorption liquid at the bottom of the absorption tower 1 enters the downstream process system through the formaldehyde liquid pipeline 6.

Claims

1. An apparatus for cleaning paraformaldehyde in an absorption tower, characterized in that It includes an absorption tower, a preheater, and an alkali liquid tank. A stuffing box section is provided inside the absorption tower. A tray is fixedly arranged at the bottom of the stuffing box section, and a liquid distributor is arranged above the stuffing box section. The lower liquid inlet of the absorption tower is fixedly connected to a first desalinated water pipeline, and the liquid outlet of the first desalinated water pipeline is arranged above the liquid distributor. The bottom liquid outlet of the absorption tower is fixedly connected to a formaldehyde liquid pipeline. A circulation pipeline is fixedly connected between the formaldehyde liquid pipeline and the first desalinated water pipeline. The lower liquid inlet of the preheater is fixedly connected to a boiler water pipeline, and a high-temperature boiler water pipeline is fixedly connected between the upper liquid outlet of the preheater and the formaldehyde liquid pipeline between the bottom liquid outlet of the absorption tower and the circulation pipeline. The lower liquid outlet of the alkali liquid tank is fixedly connected to the circulation pipeline by an alkali liquid pipeline.

2. The apparatus for cleaning paraformaldehyde in an absorption tower according to claim 1, characterized in that The inner cavity of the preheater includes a tube side and a shell side. The top air inlet of the preheater is fixedly connected to a steam inlet pipeline, and the bottom air outlet of the preheater is fixedly connected to a steam discharge pipeline.

3. The device for cleaning paraformaldehyde in the absorption tower according to claim 1 or 2, characterized in that The upper liquid inlet of the absorption tower is fixedly connected to a second desalinated water pipeline.

4. The apparatus for cleaning paraformaldehyde in an absorption tower according to claim 3, wherein The lower air inlet of the absorption tower is fixedly connected to a first formaldehyde gas pipeline, and the gas outlet of the first formaldehyde gas pipeline is arranged below the tray.

5. The device for cleaning paraformaldehyde in an absorption tower according to claim 4, characterized in that A second formaldehyde gas pipeline is fixedly connected between the top gas outlet of the absorption tower and the first formaldehyde gas pipeline.

6. The device for cleaning paraformaldehyde in an absorption tower according to claim 1 or 2 or 4 or 5, characterized in that A remote transmission liquid level gauge is fixedly arranged on the absorption tower between the liquid distributor and the tray.

7. The device for cleaning paraformaldehyde in an absorption tower according to claim 6, characterized in that A spare pipeline is fixedly connected between the formaldehyde liquid pipeline between the bottom liquid outlet of the absorption tower and the high-temperature boiler water pipeline, the alkali liquid pipeline, and the circulation pipeline between the first desalinated water pipelines. Circulation pumps are fixedly installed on the spare pipeline, the formaldehyde liquid pipeline between the spare pipeline and the high-temperature boiler water pipeline, the high-temperature boiler water pipeline, and the alkali liquid pipeline.

8. The apparatus for cleaning paraformaldehyde in an absorption tower according to claim 7, wherein A first solenoid valve and a mass flowmeter are fixedly installed in sequence along the medium flow direction on the formaldehyde liquid pipeline between the circulation pipeline and the outlet of the formaldehyde liquid pipeline. A second solenoid valve is fixedly installed on the first desalinated water pipeline between the inlet of the first desalinated water pipeline and the circulation pipeline. A third solenoid valve is fixedly installed on the formaldehyde liquid pipeline between the circulation pump on the formaldehyde liquid pipeline and the high-temperature boiler water pipeline.

9. The device for cleaning paraformaldehyde in an absorption tower according to claim 7 or 8, characterized in that A fourth solenoid valve is fixedly installed on the high-temperature boiler water pipeline at the outlet of the circulation pump on the high-temperature boiler water pipeline. A fifth solenoid valve is fixedly installed on the alkali liquid pipeline at the outlet of the circulation pump on the alkali liquid pipeline. A sixth solenoid valve is fixedly installed on the spare pipeline at the outlet of the circulation pump on the spare pipeline. A seventh solenoid valve is fixedly installed on the circulation pipeline between the first desalinated water pipeline and the spare pipeline. An eighth solenoid valve is fixedly installed on the circulation pipeline between the alkali liquid pipeline and the formaldehyde liquid pipeline.

10. The device for cleaning paraformaldehyde in an absorption tower according to claim 9, wherein It further includes a controller. The remote transmission liquid level gauge, circulation pumps, first solenoid valve, second solenoid valve, third solenoid valve, fourth solenoid valve, fifth solenoid valve, sixth solenoid valve, seventh solenoid valve, eighth solenoid valve, and mass flowmeter are all electrically connected to the controller.

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