CN112454725A

CN112454725A - Polyethylene gas removing device

Info

Publication number: CN112454725A
Application number: CN201910852478.XA
Authority: CN
Inventors: 周姣龙; 朱洁; 赵泽昊; 唐勇; 孙秀丽; 朱本虎; 李军方
Original assignee: Shanghai Institute of Organic Chemistry of CAS
Current assignee: Shanghai Institute of Organic Chemistry of CAS
Priority date: 2019-09-09
Filing date: 2019-09-09
Publication date: 2021-03-09

Abstract

The invention provides a polyethylene gas removing device, in particular to a device for removing VOC (volatile organic compounds) and reducing odor grade of polymers, which comprises: a wet nitrogen stripper (2); the feeding valve group (8) is positioned at the upstream of the wet nitrogen stripping tower, is connected with a top feeding hole of the wet nitrogen stripping tower and is used for controlling PE resin to enter the wet nitrogen stripping tower; and the discharge valve group (9) is positioned at the downstream of the wet nitrogen gas stripping tower and is used for controlling the PE resin to flow out of the wet nitrogen gas stripping tower. The device and the method are adopted to remove VOC in PE resin and reduce odor grade, the VOC content in the PE resin discharged and packaged finally can be as low as below 1ppm, the odor grade can be as low as 3 grade generally, and the odor grade can be as low as below 2 grade.

Description

Polyethylene gas removing device

Technical Field

The invention belongs to the field of polymer production, and particularly provides a device for efficiently removing polyethylene VOC and reducing odor and a corresponding method.

Background

In recent years, the requirements for light weight of automobile products, environmental protection of household electrical appliances and food contact materials, and the like are increasing. Polyethylene (PE, including LDPE, LLDPE, HDPE, UHMWPE, CPE, etc.) resin has the excellent comprehensive properties of no toxicity, small density, easy processing, high impact strength, good corrosion resistance and heat resistance, high cost performance, etc., so the Polyethylene (PE) resin is widely applied to interior and exterior trims of automobiles, household electrical appliances and food packaging materials.

Influenced by multiple factors such as the purity of a polymerized monomer, catalyst residue, a polymerization process, decomposition of an auxiliary agent, degradation of resin and the like, the problems of releasing Volatile Organic Compounds (VOC) to different degrees, polluting the environment and harming the health of people still commonly exist in the PE resin sold in the market. With the increasing awareness of environmental protection, the legal requirements related to environmental protection are increasing, the pollution problem in the vehicle is more and more emphasized by consumers and manufacturers, most of the automobile manufacturers begin to implement the european standard (VDA 277 standard of the german automobile industry association) to strictly control the VOC of the parts, and the total carbon volatilization of the interior material is required to be less than 80 μ g C/g. The newly revised national standard GB 4806.1-2016 food contact material and product general safety requirement clearly requires that the food contact material and the product have no smell touch. In addition, because the content of VOC in the existing polyethylene resin is high, the produced PE resin needs to be replaced repeatedly after entering a packaging bin, on one hand, the difficulty of a packaging process is increased, and on the other hand, the phenomenon that replacement gas exceeds the standard and is discharged frequently occurs along with the emergence of new atmospheric emission laws and regulations, so that the VOC release problem and the odor problem in the PE resin also become one of the problems to be solved urgently.

In view of the foregoing, there is a lack in the art of a method for removing VOCs from PE resins to reduce odor levels.

Disclosure of Invention

The invention aims to provide a method for removing VOC in PE resin and reducing odor grade.

In a first aspect of the present invention, there is provided a polyethylene gas removal apparatus, comprising:

a wet nitrogen stripper (2);

the feeding valve group (8) is positioned at the upstream of the wet nitrogen stripping tower, is connected with a top feeding hole of the wet nitrogen stripping tower and is used for controlling PE resin to enter the wet nitrogen stripping tower;

and the discharge valve group (9) is positioned at the downstream of the wet nitrogen gas stripping tower and is used for controlling the PE resin to flow out of the wet nitrogen gas stripping tower.

In another preferred embodiment, the wet nitrogen stripping tower is a tower in which the material in the tower is stacked and flows in a dense phase moving bed structure.

In another preferred example, the wet nitrogen stripping tower is a tower with a hot water collecting device arranged in the bottom.

In another preferred embodiment, in the wet nitrogen stripping tower, hot nitrogen is aerated from the bottom of the tower to generate wet nitrogen.

In another preferred example, the device comprises an external wet nitrogen generating device, and after being generated in a wet nitrogen stripping tower, the wet nitrogen is introduced into the wet nitrogen stripping tower to contact with the material.

In another preferred example, the feeding valve group is a rotary feeding valve group.

In another preferred example, the discharge valve group is a rotary discharge valve group.

In another preferred example, the rotary feeding valve group is a combination of two or more rotary dischargers.

In another preferred example, the rotary discharging valve group is a combination of two or more rotary dischargers.

In another preferred embodiment, the rotary discharger is in the form of a gravity flap valve or a flap valve.

In another preferred embodiment, the upstream refers to the upstream of the flow direction of the PE resin.

In another preferred embodiment, said wet nitrogen stripper further comprises a steam rising porous plate disposed in said stripper body.

In another preferred embodiment, the device further comprises a predehydration tower (1) located upstream of the inlet valve group.

In another preferred example, the predehydration tower is a predehydration tower with the existing structure of the original PE device.

In another preferred embodiment, the predehydration tower is a centrifugal dehydration tower.

In another preferred example, the device also comprises a condenser (6), wherein the inlet of the condenser is connected with the tail gas outlet of the wet nitrogen stripping tower, and the outlet of the condenser is connected with a condensate tank (7).

In another preferred example, the device further comprises a circulating water cooling system, and the circulating water cooling system is used for rapidly cooling the PE resin discharged from the wet nitrogen stripping tower.

In another preferred embodiment, the circulating water delivery device includes:

the heat exchanger (3) is positioned at the downstream of the discharge valve group and is connected with the circulating water tank through a delivery pump (4);

the venturi feeder (5), the first entry of venturi feeder links to each other with the valves of unloading, the second entry with the heat exchanger link to each other.

In another preferred example, the tail gas outlet of the wet nitrogen stripping tower is connected with the condenser through a blower (10).

In another preferred example, the blower is a centrifugal fan or a roots fan.

In another preferred example, the device further comprises a nitrogen heater (11), wherein the nitrogen heater is positioned at the upstream of the condenser and is used for heating and recycling the tail gas discharged from the tail gas outlet of the wet nitrogen stripping tower.

In a second aspect of the present invention, a method for removing VOC and reducing odor level of a polymer is provided, which is characterized by comprising the steps of:

(1) introducing the resin into a feeding valve group (8) and feeding the resin into a top feeding hole of a wet nitrogen stripping tower (2);

(2) introducing wet nitrogen into the wet nitrogen stripping tower, and exchanging heat with the resin to heat the resin to 50-95 ℃, so that VOC molecules in the resin are resolved;

(3) the resin is discharged by controlling a rotary discharging valve group (9).

In another preferred embodiment, the wet nitrogen is saturated wet nitrogen (i.e., the water vapor content in the nitrogen corresponds to the saturated water vapor partial pressure of the temperature to which the resin is heated).

In another preferred example, the wet nitrogen gas is unsaturated wet nitrogen gas.

In another preferred embodiment, the wet nitrogen is pure hot nitrogen.

In another preferred example, in the step (2), the resin is heated to 70-95 ℃, and more preferably 80-90 ℃.

In another preferred example, in the step (2), the resin stays in the wet nitrogen stripping tower for 0.5 to 5 hours, preferably 1 to 2 hours.

In another preferred embodiment, the method further comprises the steps of: (4) and introducing the resin into a Venturi feeder (5) to mix the resin with condensed water, so that the resin is subjected to quenching and cooling and then is conveyed to a downstream centrifugal dehydration process of the device.

In another preferred example, the condensed water comes from a conveying circulating water tank, is cooled by a heat exchanger (3), and is conveyed by a conveying pump (4) to enter a Venturi feeder (5).

In another preferred embodiment, the material entering the tower from the top of the tower moves from top to bottom in the tower as a dense phase moving bed.

In another preferred example, in the step (4), the resin is quenched in a venturi feeder to reduce the temperature to below 60 ℃, preferably to below 50 ℃, and more preferably to below 40 ℃.

In another preferred example, the step (4) further includes: the treated resin is firstly collected in a storage bin, and then is conveyed to the subsequent working procedures after being cooled by nitrogen.

In another preferred example, the step (4) further includes: and further cooling the treated resin through other cooling facilities.

In another preferred embodiment, the further cooling means is selected from the group consisting of: converter equipment with a cooling coil cooler or stirring equipment to be cooled.

In another preferred example, before the step (1), the method further comprises the steps of: the resin is introduced into a predehydration tower 1 for predehydration.

In another preferred embodiment, after the pre-dehydration step, the water content of the resin is 1 to 10 wt%, preferably 1 to 5 wt%.

In another preferred example, the resin is a mixture of resin and water from an underwater pelletizing process of a PE device.

In another preferred example, after the pre-dehydration step is completed, the removed water is returned to the underwater pelletizing process.

In another preferred embodiment, the method further comprises the steps of: and tail gas is discharged through a tail gas outlet of the wet nitrogen gas stripping tower.

In another preferred example, the tail gas is discharged, enters a condenser (6) for condensation and then enters a condensate tank (7).

In another preferred embodiment, the method further comprises the step of introducing the non-condensable components in the tail gas into a tail gas treatment system, mixing the tail gas with the supplemented fresh nitrogen, heating the mixture by a nitrogen heater (11), and then introducing the mixture into the wet nitrogen stripping tower (2) again.

In another preferred embodiment, the non-condensable components are in fixed rows, preferably the amount of fixed rows is determined according to the VOC content of the nitrogen after condensation.

In another preferred embodiment, the circulated nitrogen is heated to 50-95 ℃ by steam, preferably 70-95 ℃, and more preferably 80-90 ℃.

In another preferred embodiment, in said steps (1) to (3), the oxygen content of the gas phase component in the stripper is lower than 1%, preferably lower than 0.1%, more preferably lower than 100 ppm.

It is to be understood that within the scope of the present invention, the above-described features of the present invention and those specifically described below (e.g., in the examples) may be combined with each other to form new or preferred embodiments. Not to be reiterated herein, but to the extent of space.

Drawings

Fig. 1 is a schematic diagram of the structure of the polyethylene VOC removal, odor-rating reducing device of the present invention.

The system comprises a pre-dehydrator 1, a wet nitrogen steaming tower 2, a heat exchanger 3, a delivery pump 4, a Venturi feeder 5, a condenser 6, a condensate tank 7, a rotary feeding valve bank 8, a rotary discharging valve bank 9, a blower 10 and a nitrogen heater 11;

21-underwater pelletizing system, 22-underwater pelletizing circulating water tank, 24-CWR (circulating cooling water backwater), 25-conveying circulating water tank, 26-centrifugal dehydration process, 27-steam rising perforated plate, 28-fresh nitrogen flow, 29-steam flow, 30-tail gas treatment system and 31-CWS (circulating cooling water supply).

Detailed Description

The present inventors have conducted extensive and intensive studies and studies for a long time to provide an apparatus for removing VOC from a polymer resin to reduce odor level and a method thereof. The device can fully remove the residual polyethylene in the resin through a wet nitrogen gas stripping and removing process after gas diffusion and migration. Based on the above findings, the inventors have completed the present invention.

Method for removing VOC (volatile organic compounds) in polyethylene and reducing odor grade

In order to overcome the defects of the prior art, reduce the VOC content in PE resin products in the prior production device, reduce the odor level, improve the product quality and reduce the VOC emission problem in the packaging process of the production device, the invention provides a process method for efficiently removing the VOC in the PE resin and improving the odor, which has the principle that the resin is kept for a certain time at a certain temperature, the low-molecular VOC wrapped in the PE resin is fully migrated and diffused out and then stripped and removed by wet nitrogen gas, and under the condition that the resin is not melted and agglomerated, the higher the temperature is, the better the removal effect is: with the increase of the temperature, the chain segment movement becomes more obvious, the small crystal regions melt, the chain segment movement of the transition region and the amorphous region is violent, and the chain segments of the regions can move and rearrange and crystallize to form coarse crystal plates at the same time, so that the VOC small molecules wrapped in the resin are promoted to be fully migrated and diffused; on the other hand, with the rise of temperature, the free volume of a molecular chain is enlarged, the diffusion coefficient and the vapor pressure of VOC molecules wrapped in the resin are also increased, so that the VOC molecules are easier to migrate from the inside of the resin and gather on the surface of the material, and then the VOC content in the resin product finally reaches the requirements of VDA277 and GB 4806.1-2016 through wet nitrogen stripping removal.

According to the process, a set of wet nitrogen gas stripping equipment and auxiliary equipment is added between an underwater pelletizing process and a particle centrifugal dehydration process of the conventional PE process device, materials are kept at a certain temperature and stay for a certain time in the process, so that VOC is resolved from resin and is taken out through steam stripping, mixed gas obtained by stripping is subjected to fixed-discharge and then condensed, wherein non-condensable gas and VOC are removed to a field tail gas treatment system, and condensed water returns to an underwater pelletizing system. The specific process is as follows:

firstly, a mixture of water and PE resin conveyed from an upstream underwater pelletizing process is firstly dehydrated in newly-added pre-dehydration equipment until the water content of the resin is about 1-10%. And the pre-dehydrated PE resin is continuously fed into a wet nitrogen steaming tower from the top through a two-stage material transfer valve, and water from the pre-dehydration tower returns to an upstream underwater pelletizing process through a pump.

Secondly, after entering the steam steaming tower, the PE resin is piled up in a dense phase moving bed and moves slowly from top to bottom, and certain retention time is ensured. The tower is internally provided with wet nitrogen pipelines which are uniformly distributed to discharge saturated wet nitrogen at a certain temperature for heating the materials to a certain temperature range. In order to reduce the nitrogen consumption, a closed circulation system is adopted for nitrogen. Meanwhile, in order to prevent VOC from being enriched in the system, a continuously discharged mixed gas is required at the top of the tower, after the mixed gas is condensed, the uncondensed tail gas is sent to a field tail gas treatment system, condensed liquid is collected and then returned to the tower, liquid level control is carried out in the tower, and redundant water is sent to an underwater pelletizing system. After the non-condensable gas is discharged, the same volume of nitrogen gas needs to be supplemented at the same time.

Thirdly, the material from the tower bottom enters a Venturi feeder after passing through a two-stage material transferring valve, is mixed with cooling water and is rapidly cooled, and then is conveyed to a downstream centrifugal dehydration process.

The equipment for realizing the method comprises the following steps:

1-a pre-dehydrator for removing a large amount of water from the PE resin conveyed from the upstream underwater pelletizing process.

2-wet nitrogen gas stripping tower, the material is heated to a certain temperature by saturated wet nitrogen gas in the tower, and stays for a certain time, so that VOC remained in PE resin is thoroughly analyzed out and is brought out by the wet nitrogen gas.

And 3-a heat exchanger for cooling the water for conveying and cooling the hot PE resin.

And 4, a delivery pump for delivering water in the circulating water tank into the Venturi feeder.

And 5-a Venturi feeder, wherein the PE resin is collected and mixed with cooling water from a conveying circulating water tank to carry out quenching and cooling on the resin, and then the resin is conveyed to a downstream centrifugal dehydration process.

6-a condenser for cooling the mixture of steam and VOC coming out of the steaming tower.

And 7-a condensate tank for collecting the cooled condensate.

8-rotating the feed valve group, controlling the amount and speed of the resin entering the steaming tower, and simultaneously preventing the wet nitrogen from entering the predehydration tower.

And 9-rotating the discharging valve group to control the discharging speed and the discharging amount of the resin of the steaming tower and prevent steam from entering the pre-dewatering tower.

10-blower for blowing hot nitrogen gas into hot water and providing power for wet nitrogen gas circulation.

11-Nitrogen heater.

The method and apparatus can be used not only for VOC removal of freshly made PE resins but also for VOC removal of existing PE resins. In addition, the method and the device have good stripping effect, so that the method and the device can be used for removing some polar substances, such as sulfur-containing and oxygen-containing small molecules, thereby reducing the odor grade of the PE resin product.

The invention is characterized in that:

(1) the VOC removal in the PE resin is carried out by adopting the device and the method, the VOC content in the PE resin which is finally discharged and packaged is lower than that of the untreated PE resin, the VOC content can be as low as below 1ppm (tested by VDA 277), the odor grade can be generally as low as 3 grade, the odor grade can be as low as 2 grade (tested by VW 50180), and the VOC content and the odor grade are far lower than those in the PE resin with the same trade mark sold in the market.

(2) The method has simple treatment process, namely only one set of wet nitrogen stripping tower and auxiliary facilities are needed to be added between the two original working procedures, the layout is small, and the operation and the layout of the original device are not influenced.

(3) The method adopts wet nitrogen gas for gas stripping, has high heat transfer efficiency, controls a proper temperature interval in the treatment process, and quickly analyzes VOC molecules, so the treatment efficiency is high, the using amount of steam and nitrogen is small, the quality of resin is not influenced, and the phenomena of caking and the like which influence the operation of the device are not generated.

(4) The investment and the operation cost of the device are low, and the quality of the product is improved.

The process flow of the method for efficiently removing the VOC from the PE resin and reducing the odor grade by combining the attached drawing 1 is described as follows:

step 1) the mixture of resin and water from the underwater pelletizing system 21 of the PE device enters a predehydration tower 1 for dehydration treatment, and the removed water returns to an underwater pelletizing circulating water tank 22 and is reused in the underwater pelletizing process.

And 2) the wet PE resin subjected to the pre-dehydration treatment in the step 2) enters a feeding hole in the top of the wet nitrogen stripping tower 2 through a rotary feeding valve group 8.

And 3) after entering a wet nitrogen stripping tower 2 provided with a steam rising porous plate 27, carrying out heat exchange with wet nitrogen (formed by mixing a fresh nitrogen flow 28 and a steam flow 29) from a tower kettle, heating the PE resin to 50-95 ℃, and desorbing VOC molecules in the resin. The material entering the tower from the top of the tower moves from top to bottom in the tower in a dense phase moving bed.

And 4) controlling the discharging of the pre-dehydrated PE resin by a rotary discharging valve group 9.

And (3) the PE resin discharged from the tower in the step 5) enters a Venturi feeder 5, and is cooled by a heat exchanger 3 (wherein the heat exchanger 3 is provided with a circulating cooling water supply device 31 and a circulating cooling water return device 24) from a conveying circulating water tank 25 in the Venturi feeder, and then the PE resin is mixed with water conveyed by a conveying pump 4, quenched and cooled, and then conveyed to a centrifugal dehydration process 26 at the downstream of the device.

And 6) in order to prevent the analyzed VOC from being enriched in the system, the mixed gas from the wet nitrogen gas stripping tower 2 is condensed by a condenser 6, one fixed exhaust noncondensable tail gas enters a tail gas treatment system 30 on the device site, the condensate liquid returns to a condensate tank 7, and most of the nitrogen gas is mixed with a supplemented fresh nitrogen gas flow 28 and then is heated by a nitrogen gas heater 11 and then returns to the wet nitrogen gas stripping tower 2.

To verify the effectiveness of the device, a set of devices with a throughput of 1Kg/h was processed and subjected to the following tests:

example 1

The production apparatus was pelletized underwater, and then subjected to centrifugal dehydration treatment, and high-pressure polyethylene particles (LDPE, production apparatus packaging material VOC content: 120ppm, odor grade 4) containing 1% of water were filled in a wet nitrogen stripping tower of an experimental apparatus. The tower bottom is provided with a water accumulation tray, water is heated to 90 ℃ by steam, nitrogen is introduced into hot water, the inside of the tower is then ascended into the tower to heat polyethylene granules, and after the polyethylene granules are heated for 1 hour, the materials are quenched to 45 ℃ by cold water. Discharging, and carrying out centrifugal dehydration and air blow drying on the polyethylene resin according to the treatment method of an industrial device.

VOC content (VDA 277): 0.38 ppm; odor grade: and (2) level.

Example 2

The production apparatus was pelletized underwater, and then subjected to centrifugal dehydration treatment, and high-density polyethylene particles (HDPE, slurry method, production apparatus packaging material VOC content: 160ppm, odor grade 4) containing 1% of water were charged into a wet nitrogen stripping tower of an experimental apparatus. The tower bottom is provided with a water accumulation tray, water is heated to 90 ℃ by steam, nitrogen is introduced into hot water, the inside of the tower is then ascended into the tower to heat polyethylene granules, and after the polyethylene granules are heated for 1 hour, the materials are quenched to 45 ℃ by cold water. Discharging, and carrying out centrifugal dehydration and air blow drying on the polyethylene resin according to the treatment method of an industrial device.

VOC content (VDA 277): 25 ppm; odor grade: and (2) level.

Example 3

The production apparatus was pelletized underwater, and then subjected to centrifugal dehydration treatment, and high-density polyethylene particles (HDPE, gas phase method, production apparatus packaging material VOC content: 180ppm, odor grade 4) containing 1% of water were filled in a wet nitrogen stripping tower of an experimental apparatus. The tower bottom is provided with a water accumulation tray, water is heated to 90 ℃ by steam, nitrogen is introduced into hot water, the inside of the tower is then ascended into the tower to heat polyethylene granules, and after the polyethylene granules are heated for 1 hour, the materials are quenched to 45 ℃ by cold water. Discharging, and carrying out centrifugal dehydration and air blow drying on the polyethylene resin according to the treatment method of an industrial device.

VOC content (VDA 277): 55 ppm; odor grade: and 3, grade.

Example 4

The production apparatus was pelletized underwater, and then subjected to centrifugal dehydration treatment, and high-pressure polyethylene particles (LDPE, production apparatus packaging material VOC content: 120ppm, odor grade 4) containing 1% of water were filled in a wet nitrogen stripping tower of an experimental apparatus. The tower bottom is provided with a water accumulation tray, water is heated to 80 ℃ by steam, nitrogen is introduced into hot water, the inside of the tower is then ascended into the tower to heat polyethylene granules, and after the heating is carried out for 1.5 hours, the materials are quenched to 55 ℃ by cold water. Discharging, and carrying out centrifugal dehydration and air blow drying on the polyethylene resin according to the treatment method of an industrial device.

VOC content (VDA 277): 15 ppm; odor grade: and 3, grade.

Example 5

The production apparatus was pelletized underwater, and then subjected to centrifugal dehydration treatment, and high-density polyethylene particles (HDPE, slurry method, production apparatus packaging material VOC content: 160ppm, odor grade 4) containing 1% of water were charged into a wet nitrogen stripping tower of an experimental apparatus. The tower bottom is provided with a water accumulation tray, water is heated to 80 ℃ by steam, nitrogen is introduced into hot water, the inside of the tower is then ascended into the tower to heat polyethylene granules, and after the polyethylene granules are heated for 1 hour, the materials are quenched to 55 ℃ by cold water. Discharging, and carrying out centrifugal dehydration and air blow drying on the polyethylene resin according to the treatment method of an industrial device.

VOC content (VDA 277): 35 ppm; odor grade: and 3, grade.

Example 6

The production apparatus was pelletized underwater, and then subjected to centrifugal dehydration treatment, and high-density polyethylene particles (HDPE, gas phase method, production apparatus packaging material VOC content: 180ppm, odor grade 4) containing 1% of water were filled in a wet nitrogen stripping tower of an experimental apparatus. The tower bottom is provided with a water accumulation tray, water is heated to 80 ℃ by steam, nitrogen is introduced into hot water, the inside of the tower is then ascended into the tower to heat polyethylene granules, and after the heating is carried out for 1 hour, the materials are quenched to 45 ℃ by cold water. Discharging, and carrying out centrifugal dehydration and air blow drying on the polyethylene resin according to the treatment method of an industrial device.

VOC content (VDA 277): 55 ppm; odor grade: and 3, grade.

All documents referred to herein are incorporated by reference into this application as if each were individually incorporated by reference. Furthermore, it should be understood that various changes and modifications of the present invention can be made by those skilled in the art after reading the above teachings of the present invention, and these equivalents also fall within the scope of the present invention as defined by the appended claims.

Claims

1. A polyethylene gas removal unit, said unit comprising:

a wet nitrogen stripper (2);

2. The apparatus according to claim 1, characterized in that it further comprises a predehydration tower (1) upstream of the inlet valve group.

3. The apparatus according to claim 1, further comprising a condenser (6), wherein the condenser inlet is connected to the off-gas outlet of the wet nitrogen stripper column and the condenser outlet is connected to a condensate tank (7); preferably, the device also comprises a nitrogen heater (11) which is positioned at the upstream of the condenser and used for heating and recycling the tail gas discharged from the tail gas outlet of the wet nitrogen stripping tower.

4. The apparatus according to claim 1, further comprising a circulating water cooling system for rapidly cooling the PE resin discharged from the wet nitrogen stripper; preferably, the circulating water cooling system includes:

5. A method for VOC removal and odor level reduction of polymers, comprising the steps of:

6. The method of claim 5, wherein said method further comprises the steps of: (4) and introducing the resin into a Venturi feeder (5) to mix the resin with condensed water, so that the resin is subjected to quenching and cooling and then is conveyed to a downstream centrifugal dehydration process of the device.

7. The method of claim 6, wherein prior to said step (1), further comprising the step of: the resin is introduced into a predehydration tower 1 for predehydration.

8. The method of claim 6, wherein said method further comprises the steps of: discharging tail gas through a tail gas outlet of the wet nitrogen gas stripping tower; preferably, the tail gas is discharged, enters a condenser (6) for condensation and then enters a condensate tank (7).

9. The method of claim 8, further comprising passing the non-condensable components of the tail gas to a tail gas treatment system, mixing with make-up fresh nitrogen, heating with a nitrogen heater (11), and passing the heated mixture to the wet nitrogen stripper column (2).

10. The process according to claim 5, wherein in steps (1) to (3) the oxygen content of the gas phase components in the stripper is lower than 1%, preferably lower than 0.1%, more preferably lower than 100 ppm.