CN212687940U

CN212687940U - PET continuous production line capable of regularly descaling

Info

Publication number: CN212687940U
Application number: CN202021372556.0U
Authority: CN
Inventors: 臧红辉; 舒文兵; 录翰武; 裴书伟
Original assignee: Chongqing Wankai New Material Technology Co Ltd
Current assignee: Chongqing Wankai New Material Technology Co Ltd
Priority date: 2020-07-13
Filing date: 2020-07-13
Publication date: 2021-03-12
Anticipated expiration: 2030-07-13

Abstract

The utility model relates to a wash the scale removal field, disclose a but PET continuous production line of periodic cleaning, including the esterification reaction jar body that communicates in proper order, the polycondensation reaction jar body, spray condenser and vacuum system, it has the ethylene glycol storage tank to spray the condenser intercommunication, and it has the liquid return pipe to spray the intercommunication between condenser and the ethylene glycol storage tank, still includes belt cleaning device, and belt cleaning device includes first scavenge pipe and the confession liquid mechanism that is used for providing hot ethylene glycol, and first scavenge pipe one end feeds through with confession liquid mechanism, and the first scavenge pipe other end is close to the one end intercommunication that sprays the condenser with liquid return pipe, is equipped with the first valve that is used for controlling first scavenge pipe on the first scavenge pipe. The utility model discloses can be used for solving among the prior art dirt washing need shut down the washing and cause and hinder the problem of production process.

Description

PET continuous production line capable of regularly descaling

Technical Field

The utility model relates to a wash the scale removal field, concretely relates to but PET continuous production line of periodic descaling.

Background

Polyethylene terephthalate (PET for short) is prepared by esterification of terephthalic acid and ethylene glycol to synthesize dihydroxy ethyl terephthalate, and then polycondensation reaction. The polycondensation reaction in the PET production process needs to be carried out under the negative pressure vacuum condition, during actual production, the vacuum system is communicated with the polycondensation reaction tank body, negative pressure is formed in the polycondensation reaction tank body through the vacuum system, impurities, water vapor and partially vaporized ethylene glycol generated by some side reactions in the process enter the spray condenser under the action of the negative pressure, and then the impurities, the water vapor and the partially vaporized ethylene glycol enter the ethylene glycol storage tank after condensation and purification so as to be recycled. The impurities in the ethylene glycol after spray condensation are easily attached to the pipeline in the flowing process, the influence on some pipelines with large pipe diameters such as a spray pipeline is slightly small, but the impurities are scaled after being attached to some pipelines with small pipe diameters such as a pipeline reflowing to an ethylene glycol storage tank, so that the flow in the pipeline is seriously influenced, and even the pipeline is blocked, so that the whole production process is influenced, and the production is not facilitated.

In order to solve the problems, two modes are generally adopted in the prior art to clean up dirt in the pipeline, firstly, the pipeline is knocked by a wood rod to vibrate, so that the dirt on the inner wall of the pipeline falls off, the mode has the problem of incomplete cleaning, and meanwhile, the pipeline is shaken for a long time, so that the problem of liquid leakage caused by the looseness of the pipeline joint is easily caused; secondly, after the equipment stops producing, the dissolving medium is introduced to dissolve and wash dirt on the inner wall of the pipeline, the mode needs to be shut down and cleaned, on one hand, the production process needs to be delayed, on the other hand, after other dissolving media are used for cleaning, the dissolving media need to be dried to eliminate the influence of the dissolving media on the reaction of the production process, and the whole process is complicated, the workload is large, and the consumed time is long.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a but PET continuous production line of periodic cleaning to dirt washs needs the shut down washing and causes and hinders the problem of production process among the solution prior art in the pipeline.

In order to achieve the above purpose, the utility model adopts the following technical scheme: the utility model provides a but PET continuous production line of periodic descaling, including the esterification reaction jar body that communicates in proper order, the polycondensation reaction jar body, spray condenser and vacuum system, it has the ethylene glycol storage tank to spray the condenser intercommunication, it has the liquid return pipe to spray the intercommunication between condenser and the ethylene glycol storage tank, still include belt cleaning device, belt cleaning device includes first scavenge pipe and the confession liquid mechanism that is used for providing hot ethylene glycol, first scavenge pipe one end and confession liquid mechanism intercommunication, the first scavenge pipe other end is close to the one end intercommunication that sprays the condenser with the liquid return pipe, be equipped with the first valve that is used for controlling first scavenge pipe on the first scavenge pipe.

The principle and the advantages of the scheme are as follows: in practical application, the raw materials react in an esterification reaction tank to synthesize the dihydroxy ethyl terephthalate, and then the dihydroxy ethyl terephthalate is subjected to polycondensation reaction in a polycondensation reaction tank to obtain the PET. In the polycondensation reaction process, a vacuum system enables negative pressure to be formed in the polycondensation reaction tank body so as to promote the reaction, and due to the action of the negative pressure, impurities with low boiling point, water vapor and partially vaporized ethylene glycol in the polycondensation reaction tank body enter a spray condenser, and after spray cooling, the impurities, the water vapor and the partially vaporized ethylene glycol enter an ethylene glycol storage tank through a liquid return pipe to be recovered. In the process, hot glycol in the liquid supply mechanism enters the return pipe through the first cleaning pipe by adjusting the first valve, and dirt on the inner wall of the return pipe is cleaned by the hot glycol.

1. According to the scheme, the dirt is cleaned by hot glycol, and is washed by the hot glycol, so that the dirt is removed more thoroughly; meanwhile, partial dirt can be promoted to be dissolved through temperature rise, so that the descaling effect is improved; in addition, the ethylene glycol is one of raw materials in the production of PET, so that the whole process and the product are not negatively influenced.

2. This scheme sets up belt cleaning device, utilizes the external first scavenge pipe of back flow, through the first scavenge pipe of first valve control, closes first valve when need not the scale removal, opens first valve when needs scale removal, makes first scavenge pipe and back flow intercommunication, descale under the condition that need not to stop production, can not delay the production process, can regularly through adjusting first valve, makes first scavenge pipe and back flow intercommunication, washs the dirt in the back flow.

Preferably, as an improvement, the liquid supply mechanism is a process rectifying tower, the inlet end of the process rectifying tower is communicated with an exhaust port of the esterification reaction tank body, and the lower outlet end of the process rectifying tower is communicated with the first cleaning pipe and the ethylene glycol storage tank. The mixture of the water vapor and the ethylene glycol mainly comes out from an exhaust port of an esterification reaction tank body, the ethylene glycol is purified and separated by a process rectifying tower through the difference of boiling points of the water vapor and the ethylene glycol, the heating temperature is between the boiling points of the water and the ethylene glycol, the water vapor is discharged from an upper outlet end of the process rectifying tower in the rectifying process, the ethylene glycol enters a first cleaning pipe from a lower outlet end of the process rectifying tower and is descaled as hot ethylene glycol, and when the descaled ethylene glycol is not needed, the ethylene glycol enters an ethylene glycol storage tank so as to be recycled. The process rectifying tower is arranged, so that the ethylene glycol discharged from the esterification reaction tank body can be purified and recovered, and the waste of raw materials is reduced; meanwhile, the ethylene glycol can be directly used for descaling after being heated in the rectification process, and the ethylene glycol does not need to be additionally heated, so that the energy loss is reduced, and the production cost is reduced.

Preferably, as an improvement, the lower outlet end of the process rectifying tower is also communicated with the feed end of the esterification reaction tank body. The purified glycol enters the esterification reaction tank body, so that the glycol in the esterification reaction tank body is sufficient, and the full esterification reaction is ensured.

Preferably, as an improvement, a glycol liquid sample tank is arranged between the spray condenser and the glycol storage tank, the outlet end of the spray condenser is communicated with the inlet end of the glycol liquid sample tank, the outlet end of the glycol liquid sample tank is communicated with the liquid return pipe, a liquid guide pipe is communicated between the outlet end of the glycol liquid sample tank and the spray end of the spray condenser, the liquid guide pipe is communicated with the liquid return pipe, and a pump is arranged on the liquid guide pipe. The ethylene glycol in the ethylene glycol storage tank is used for spraying at first, the ethylene glycol enters the spray condenser through the return pipe and the liquid guide pipe to cool the gas coming out of the polycondensation reaction tank body, and the ethylene glycol is recycled in the reaction, so that the reaction is not influenced by the spray cooling of the ethylene glycol; the liquid after spraying and condensing enters an ethylene glycol liquid sample tank to be recycled, and the liquid in the ethylene glycol liquid sample tank can be introduced into a liquid guide pipe through a pump in the process to be used as spraying liquid, so that the use of ethylene glycol in the spraying process is reduced; because the polycondensation can generate glycol continuously, the glycol in the glycol liquid sample tank is increased continuously, and the glycol is convenient to be recycled and reused subsequently.

Preferably, as an improvement, still include the thick liquids and prepare a jar body, the discharge end and the esterification reaction jar body intercommunication of the thick liquids preparation jar body, the feed end that the thick liquids were prepared a jar body is equipped with ethylene glycol feed liquor pipe, the intercommunication has the pipe between ethylene glycol feed liquor pipe and the ethylene glycol storage tank, belt cleaning device still includes the second scavenge pipe, second scavenge pipe one end and confession liquid mechanism intercommunication, the second scavenge pipe other end and ethylene glycol feed liquor pipe intercommunication are equipped with the second valve that is used for controlling the second scavenge pipe on the second scavenge pipe. The ethylene glycol in the ethylene glycol storage tank can be used as a raw material and enters the slurry preparation tank body through the guide pipe and the ethylene glycol liquid inlet pipe. In the actual production, the ethylene glycol in the ethylene glycol storage tank still contains a small amount of impurity, and ethylene glycol feed liquor intraductal diameter is less, uses for a long time and will lead to the intraductal scale deposit of ethylene glycol feed liquor, consequently adjusts the second scavenge pipe through the second valve, can regularly wash the scale removal to ethylene glycol feed liquor pipe to prevent that ethylene glycol feed liquor pipe from blockking up.

Preferably, as an improvement, the pipe diameters of the first cleaning pipe, the second cleaning pipe, the liquid guide pipe and the guide pipe are all larger than the pipe diameters of the liquid return pipe and the glycol liquid inlet pipe. So as to better clean and descale the liquid return pipe and the ethylene glycol liquid inlet pipe and prevent the liquid guide pipe and the guide pipe from being blocked.

Preferably, as a modification, two manual valves and an automatic valve are installed on the liquid return pipe, the automatic valve is located between the manual valves, and the automatic valve and the manual valve are connected in series. In general, the flow of the liquid return pipe is adjusted through an automatic valve, and when the automatic valve has a problem, the flow of the liquid return pipe can be adjusted through a manual valve or the automatic valve is overhauled.

Preferably, as an improvement, the liquid return pipe is further communicated with a branch pipe, two ends of the branch pipe are both communicated with the liquid return pipe, and the branch pipe is provided with a manual valve. When the passage of the automatic valve has problems or needs to be overhauled, the return pipe can be communicated through the branch pipe, and the flow can be adjusted through the manual valve on the branch pipe, so that normal production is ensured.

Preferably, as an improvement, a liquid level meter is arranged on the ethylene glycol liquid sample tank. The liquid level of the glycol liquid sample tank is monitored by a liquid level meter so as to prevent the liquid from overflowing due to excessive liquid.

Preferably, as an improvement, the catheter is provided with a cooling member. The liquid flowing through the liquid guide pipe is cooled through the cooling piece, and the spraying and condensing effect is improved.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Detailed Description

The following is further detailed by way of specific embodiments:

reference numerals in the drawings of the specification include: the device comprises a slurry preparation tank body 1, an esterification reaction tank body 2, a polycondensation reaction tank body 3, a spray condenser 4, a vacuum system 5, an ethylene glycol liquid sample tank 6, an ethylene glycol storage tank 7, an ethylene glycol liquid inlet pipe 8, a guide pipe 9, a first pump 10, a liquid return pipe 11, a liquid guide pipe 12, a second pump 13, a first cleaning pipe 14, a second cleaning pipe 15, a process rectification tower 16, a return pipe 17, a third pump 18, a first valve 19, a second valve 20, a manual valve 21, an automatic valve 22 and a branch pipe 23.

The embodiment is basically as shown in the attached figure 1:

a PET continuous production line capable of regularly descaling comprises a slurry preparation tank body 1, an esterification reaction tank body 2, a polycondensation reaction tank body 3, a spray condenser 4 and a vacuum system 5 which are sequentially communicated, wherein the outlet end of the spray condenser 4 is sequentially communicated with an ethylene glycol liquid sample groove 6 and an ethylene glycol storage tank 7. The discharge end of the slurry preparation tank body 1 is communicated with the feed end of the esterification reaction tank body 2, the feed end of the slurry preparation tank body 1 is communicated with an ethylene glycol liquid inlet pipe 8, a guide pipe 9 is communicated between the ethylene glycol liquid inlet pipe 8 and an ethylene glycol storage tank 7, and a first pump 10 is installed on the guide pipe 9. A liquid return pipe 11 is communicated between the ethylene glycol liquid sample tank 6 and the ethylene glycol storage tank 7, a liquid guide pipe 12 is communicated between the outlet end of the ethylene glycol liquid sample tank 6 and the spraying end of the spraying condenser 4, the liquid guide pipe 12 is communicated with the liquid return pipe 11, a second pump 13 and a cooling piece are installed on the liquid guide pipe 12, and a liquid level meter is installed on the ethylene glycol liquid sample tank 6 to monitor the liquid level height in the ethylene glycol liquid sample tank 6 and prevent liquid overflow.

The device further comprises a cleaning device, the cleaning device comprises a first cleaning pipe 14, a second cleaning pipe 15 and a liquid supply mechanism for providing hot ethylene glycol, the liquid supply mechanism is a process rectifying tower 16, the inlet end of the process rectifying tower 16 is communicated with an exhaust port of the esterification reaction tank body 2, and the lower outlet end of the process rectifying tower 16 is communicated with the inlet end of the esterification reaction tank body 2. A return pipe 17 is communicated between the lower outlet end of the process rectifying tower 16 and the ethylene glycol storage tank 7, a third pump 18 is arranged on the return pipe 17, the left end of the first cleaning pipe 14 is communicated with the return pipe 17, the right end of the first cleaning pipe 14 is communicated with one end of the liquid return pipe 11 close to the spray condenser 4, and a first valve 19 for controlling the first cleaning pipe 14 is arranged on the first cleaning pipe 14; the right end of the second cleaning pipe 15 is communicated with a return pipe 17, the left end of the second cleaning pipe 15 is communicated with an ethylene glycol liquid inlet pipe 8, and a second valve 20 for controlling the second cleaning pipe 15 is arranged on the second cleaning pipe 15.

The pipe diameters of the first cleaning pipe 14, the second cleaning pipe 15, the liquid guide pipe 12, the guide pipe 9 and the return pipe 17 are all larger than the pipe diameters of the liquid return pipe 11 and the glycol liquid inlet pipe 8. Two manual valves 21 and an automatic valve 22 are installed on the liquid return pipe 11, the automatic valve 22 is positioned between the manual valves 21, and the automatic valve 22 and the manual valve 21 are connected in series; the return pipe 17 is also communicated with a branch pipe 23, two ends of the branch pipe 23 are both communicated with the return pipe 17, the branch pipe 23 is provided with a manual valve 21, when the passage of the automatic valve 22 is in trouble or needs to be maintained, the branch pipe 23 is communicated with the return pipe 11, and the manual valve 21 on the branch pipe 23 is used for adjusting the flow rate so as to ensure normal production.

In the concrete implementation, the raw materials and the auxiliary materials are put into a slurry preparation tank 1 and prepared, then are led into an esterification reaction tank 2 to carry out esterification reaction to synthesize the dihydroxy ethyl terephthalate, and then are subjected to polycondensation reaction in a polycondensation reaction tank 3 to obtain the product PET.

In the esterification reaction process, the mixture of water vapor and glycol mainly comes out from the exhaust port of the esterification reaction tank body 2, the glycol is purified and separated by a process rectifying tower 16 by utilizing the difference of the boiling points of the water vapor and the glycol, the heating temperature is between the boiling points of the water and the glycol, the water vapor is discharged from the upper outlet end of the process rectifying tower 16 in the rectifying process, the glycol enters a glycol storage tank 7 from one part of the lower outlet end of the process rectifying tower 16 through a return pipe 17 for recycling, and the other part of the glycol returns to the esterification reaction tank body 2.

During the polycondensation reaction, the vacuum system 5 will make the polycondensation reaction tank 3 form negative pressure to promote the reaction, and some low boiling point impurities, water vapor and partially vaporized glycol in the polycondensation reaction tank 3 will enter the spray condenser 4 due to the negative pressure. The ethylene glycol recovered from the ethylene glycol storage tank 7 is used for spraying at the beginning, the ethylene glycol enters the spray condenser 4 through the liquid return pipe 11 and the liquid guide pipe 12 to spray and cool the gas coming out of the polycondensation reaction tank body 3, and the ethylene glycol is used as the main raw material in the reaction, so the spraying and cooling of the ethylene glycol do not influence the reaction. After spraying and cooling, the liquid is changed into liquid and enters the ethylene glycol liquid sample tank 6 for temporary storage. Because will produce ethylene glycol constantly in the polycondensation, consequently ethylene glycol content will constantly increase in the ethylene glycol liquid appearance groove 6, the liquid level height in the ethylene glycol liquid appearance groove 6 can be monitored through the level gauge to the in-process, when high too high, pump its interior liquid into catheter 12 through second pump 13, then use as spraying liquid in getting into spray condenser 4 after cooling member cools off to reach the effect of recycling.

In the process of cleaning and descaling, when the cleaning and descaling are not needed, the first valve 19 and the second valve 20 are closed. When the return pipe 17 and the ethylene glycol liquid inlet pipe 8 need to be cleaned and descaled, the first valve 19 and the second valve 20 are adjusted to enable the first cleaning pipe 14 to be communicated with the return pipe 17 and the liquid return pipe 11, the second cleaning pipe 15 to be communicated with the return pipe 17 and the ethylene glycol liquid inlet pipe 8, ethylene glycol coming out of the lower outlet end of the process rectifying tower 16 enters the ethylene glycol liquid inlet pipe 8 and the liquid return pipe 11 respectively, dirt is directly dissolved and washed by hot ethylene glycol, the temperature of the hot ethylene glycol can reach about 170 ℃, and the cleaning effect is good. And the material quantity of the liquid entering the slurry preparation tank body 1 after cleaning relative to the slurry preparation tank body 1 can be ignored, so that no negative influence is caused on the batching or the subsequent reaction.

The above description is only an example of the present invention, and the detailed technical solutions and/or characteristics known in the solutions are not described too much here. It should be noted that, for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.

Claims

1. The utility model provides a but PET continuous production line of periodic cleaning, includes the esterification reaction jar body, the polycondensation reaction jar body that communicate in proper order, sprays condenser and vacuum system, and it has the ethylene glycol storage tank to spray the condenser intercommunication, and it has liquid return pipe, its characterized in that to spray the intercommunication between condenser and the ethylene glycol storage tank: still include belt cleaning device, belt cleaning device includes first scavenge pipe and is used for providing the confession liquid mechanism of hot ethylene glycol, first scavenge pipe one end with supply liquid mechanism intercommunication, the first scavenge pipe other end and return liquid pipe are close to the one end intercommunication that sprays the condenser, are equipped with the first valve that is used for controlling first scavenge pipe on the first scavenge pipe.

2. A PET continuous production line with periodic descaling according to claim 1, wherein: the liquid supply mechanism is a process rectifying tower, the inlet end of the process rectifying tower is communicated with an exhaust port of the esterification reaction tank body, and the lower outlet end of the process rectifying tower is communicated with the first cleaning pipe and the ethylene glycol storage tank.

3. A PET continuous production line with periodic descaling according to claim 2, wherein: the lower outlet end of the process rectifying tower is also communicated with the feed end of the esterification reaction tank body.

4. A PET continuous production line with periodic descaling according to claim 3, wherein: the device is characterized in that an ethylene glycol liquid sample groove is formed between the spray condenser and the ethylene glycol storage tank, the outlet end of the spray condenser is communicated with the inlet end of the ethylene glycol liquid sample groove, the outlet end of the ethylene glycol liquid sample groove is communicated with the liquid return pipe, a liquid guide pipe is communicated between the outlet end of the ethylene glycol liquid sample groove and the spray end of the spray condenser, the liquid guide pipe is communicated with the liquid return pipe, and a pump is arranged on the liquid guide pipe.

5. A PET continuous production line capable of periodic descaling according to claim 4, characterized in that: still include the thick liquids and prepare a jar body, the discharge end and the esterification reaction jar body intercommunication of the thick liquids preparation jar body, the feed end that the thick liquids was prepared a jar body is equipped with ethylene glycol feed liquor pipe, and the intercommunication has the pipe between ethylene glycol feed liquor pipe and the ethylene glycol storage tank, and belt cleaning device still includes the second scavenge pipe, and second scavenge pipe one end and confession liquid mechanism intercommunication, the second scavenge pipe other end and ethylene glycol feed liquor pipe intercommunication are equipped with the second valve that is used for controlling the second scavenge pipe on the second scavenge pipe.

6. A PET continuous production line capable of periodic descaling according to claim 5, characterized in that: the pipe diameters of the first cleaning pipe, the second cleaning pipe, the liquid guide pipe and the guide pipe are all larger than those of the liquid return pipe and the glycol liquid inlet pipe.

7. A PET continuous production line capable of periodic descaling according to claim 6, characterized in that: two manual valves and an automatic valve are installed on the liquid return pipe, the automatic valve is located between the manual valves, and the automatic valve and the manual valves are connected in series.

8. A PET continuous production line with periodic descaling according to claim 7, wherein: the liquid return pipe is also communicated with a branch pipe, two ends of the branch pipe are both communicated with the liquid return pipe, and the branch pipe is provided with a manual valve.

9. A PET continuous production line with periodic descaling according to claim 8, wherein: and a liquid level meter is arranged on the ethylene glycol liquid sample tank.

10. A PET continuous production line with periodic descaling according to claim 9, wherein: the liquid guide pipe is provided with a cooling part.