CN102040468B - Process for recycling feedstock from polyester wastes and apparatus using the same - Google Patents

Abstract

The present invention relates to a process for recycling raw materials from polyester waste and an apparatus utilizing said process, more particularly, the present invention relates to the recycling of dimethyl terephthalate from polyethylene terephthalate (PET) A method for raw materials with ethylene glycol or polyester and an apparatus utilizing said method. More specifically, the present invention relates to a novel continuous recycling process which improves process efficiency and energy savings through recycling of the methanol vapor produced and crystallization of dimethyl terephthalate.

Description

Method for recycling raw materials from polyester waste and plant using said method

technical field

The present invention relates to a method for recycling raw materials from polyester waste and an apparatus utilizing said method, and more particularly, the present invention relates to a process for recycling polyester waste mainly comprising polyethylene terephthalate (hereinafter referred to as PET). (Bottles, magnetic films, beer bottles, oligomer slag, etc.) Methods of recycling dimethyl terephthalate (hereinafter referred to as DMT) and ethylene glycol (hereinafter referred to as EG) or raw materials for polyester and utilizing all Apparatus for the method described above.

Background technique

Nowadays, due to the proliferation of plastic products due to the development of the plastic industry, the disposal of waste materials has become a serious environmental problem.

Waste plastics are mainly treated by landfilling, incineration and recycling, and recycling of waste plastics is preferred because landfilling and incineration cause problems such as environmental pollution. Generally, recycling can be divided into material recycling and chemical recycling. In material recycling, the waste plastics generated are first collected and sorted, and then physically recycled. However, despite the economical recycling costs of material recycling, the problem is that the recycled plastics are of poor quality.

In chemical recycling, waste plastics are depolymerized to obtain plastic monomers or polymeric raw materials. In one example, PET waste from waste plastics is recycled, and the traditional process includes the following processes:

Depolymerization process The polyester waste is charged into ethylene glycol containing a depolymerization catalyst in the glycolysis reactor to depolymerize the polyester waste into bishydroxyl terephthalate (BHET) and oligomers , and then the product of partial glycolysis was charged into the transesterification reactor, and the crude DMT and EG were obtained by transesterification of the partial glycolysis product in methanol (MeOH) in the presence of a transesterification catalyst , and purify the crude DMT and EG by utilizing distillation and crystallization processes to thereby obtain the final products DMT and EG while recycling methanol to the transesterification reactor.

Regarding the transesterification reactor in the aforementioned process, U.S. Patent No. 5,051,528 discloses passing superheated methanol gas under low pressure through ethylene glycol and terephthalic acid oligomers or dimethyl terephthalate, gaseous DMT , EG and methanol are recovered from the top of the tower, thus enabling more contaminated PET to be processed. That is, BHET and oligomers were obtained by partial alcoholysis of ethylene glycol, and DMT and EG were obtained by methanolysis of BHET and oligomers. However, depolymerization to BHET by partial glycololysis takes a long reaction time because it is a reversible reaction.

In addition, the resulting BHET and oligomers were depolymerized again from gaseous methanol to form DMT and EG which were discharged in the gas phase. Therefore, high-pressure methanol cannot be used, and the reaction rate is thus slow.

Various methods for methanolysis of PET are disclosed in the patent literature. The operation is carried out under batch conditions as well as under continuous conditions, the main problem of the continuous process is that it is difficult to feed solid polyester waste to the methanolysis reactor operating at high pressure. For the aforementioned reasons, methanolysis is often carried out in a batch process despite the various disadvantages of the batch process. It is well known that the high-pressure batch process is that the depolymerization of polyester proceeds rapidly due to the high concentration of methanol in the oligomer solution, but the reaction speed increases with the limitation of reaction equilibrium due to the increase of the concentration of DMT and EG. The time decreased so that the polyester could not be completely depolymerized to DMT and EG, and about 15% remained in the form of oligomers.

On the contrary, because DMT and EG are removed through the top of the reactor, the low-pressure continuous depolymerization process is not limited by the reaction equilibrium, but its disadvantage is that the reaction rate is slower because the concentration of methanol in the reaction solution is kept low caused by the level.

Korean Patent No. 0837781 is the applicant's prior application, which discloses a method in which glycolysis reaction and methanolysis reaction are carried out simultaneously in a single reactor, and the only high-pressure reactor is thus used as polyester Dissolving tank, glycolysis reactor and methanolysis reactor. The aforementioned method can significantly increase the reaction speed, and obtain the effect of reducing the consumption of raw material methanol due to the increase of reaction efficiency.

However, in the methanolysis reactor and methanol recovery process in which the subsequent process is carried out, liquefaction of methanol vapor from the methanolysis reactor, injection of methanol through a high-pressure pump or Feedstock from the methanol storage and the process of evaporating the methanol through the evaporator.

Therefore, the aforementioned process is disadvantageous in requiring complex equipment and consuming a relatively large amount of energy, as the methanol collected in the methanol recovery column is liquefied for storage in the methanol storage and then evaporated again for delivery through the evaporator To the methanolysis reactor, liquefaction and evaporation are repeated.

Contents of the invention

technical problem

Embodiments of the present invention aim to provide a method of recycling raw materials from polyester waste such as bottles, magnetic films, oligomer slag, etc., which can simplify equipment, save energy, and obtain high-purity monomeric DMT.

More specifically, firstly, embodiments of the present invention aim to provide a process wherein methanol is separated in a rectification column (300) from a product produced in a methanolysis reactor, the second reactor (200) , and recycle it to the second reactor (200) without condensation or re-evaporation, thereby significantly saving a large amount of energy consumed due to repeated evaporation and liquefaction of the recycled methanol and simplifying the device.

Secondly, another embodiment of the present invention aims to provide a method by combining the gaseous reaction product discharged through the top of the second reactor (200) with the liquid pool at the bottom of the rectification column (300) (for example, by immersion) direct contact, and with the liquid in the tray or column section (column section) of the rectification column flowing down from the methanol reservoir (30), thereby directly liquefying DMT and EG while only evaporating the methanol in solution, thereby enabling High purity methanol is recycled to the second reactor (200) and used in the methanolysis reaction.

Third, another embodiment of the present invention aims to provide a method that can mix the methanol separated from the gaseous reaction product discharged from the top of the second reactor (200) with the methanol stored in the methanol storage (30). The feed amount of methanol is adjusted when supplying raw methanol and when recycling the mixture to the second reactor (200).

Fourth, another embodiment of the present invention aims to provide a method, wherein the methanol sent to the second reactor (200) is supplied by the methanol separated by the rectification column (300), thus there is no need to keep the methanol evaporator, heat Devices and high-pressure pumps, the rectification column played their role.

Fifth, another embodiment of the present invention aims to provide a method that only vaporizes methanol by controlling the temperature of the lower part of the rectification column (300), thereby facilitating subsequent crystallization. Sixth, still another embodiment of the present invention aims to provide a method that can freely adjust the reaction conditions and rectification conditions, thereby using back pressure when the amount of methanol discharged through the top of the rectification column (300) is too large A regulator (31) allows a portion of the methanol to be stored in the methanol storage, thereby improving productivity.

Technical solutions

The advantages, features, and aspects of the present invention will become apparent from the description of the following embodiments set forth hereinafter with reference to the accompanying drawings.

Unless defined otherwise, all scientific and technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In other instances, well-known functions and constructions are not described in detail to avoid unnecessarily obscuring the present invention.

Fig. 1 is the schematic diagram showing the whole process of the plant of recycling raw material DMT and EG by polyester waste, the plant of the present invention comprises raw material feeder (10); First reactor (100), described first reactor ( 100) using said raw material supplied by said raw material feeder (10) to carry out glycolysis reaction and methanolysis reaction in a single reactor; second reactor (200), said second reactor (200) is used to carry out methanol alcoholysis reaction to the product of described first reactor (100); Rectification tower (300), and described rectification tower (300) is used to pass through described second reactor (200) ) to separate methanol and recycle the separated gaseous methanol to said second reactor (200); and a methanol storage (30) for supplying methanol to said second reactor (200); Described rectifying tower (300).

Each component will be described in detail.

The raw material feeder (10) of the present invention is a raw material supplier, and can adopt an extruder, a screw feeder or an air lock valve, but is not limited thereto.

The first reactor (100) of the present invention is a glycolysis/methanolysis reactor in which the glycolysis reaction and the methanolysis reaction occur simultaneously, and it does not require a separate dissolution tank because DMT and oligomerization It is in which the product is generated and can significantly increase the rate of depolymerization.

The second reactor (200) allows the reactants transferred from the first reactor (100) to undergo methanolysis reaction with methanol supplied from the bubble generator (90) at the lower part of the second reactor, and while completing the depolymerization The gaseous reaction products are discharged, whereby low-grade polyester wastes containing many impurities can be processed.

In addition, the rectification column (300) allows the product of the second reactor (200) to directly contact the liquid pool at the bottom of the rectification column (300) and in the tray or column section of the rectification column flowing down from the methanol reservoir (30) liquid, so that methanol is evaporated and separated separately, and the mixture of the separated methanol and the raw methanol supplied from the methanol storage (30) is recycled to the upper part of the rectification column (300) and evaporated to the second reactor (200 ).

In addition, the methanol storage (30) for supplying methanol to the rectification column (300) also supplies methanol to the first reactor (100) at the start of operation.

The device of the present invention for recycling raw materials from polyester waste can also include a back pressure regulator (31), which is used to control the pressure of the rectifier and the methanolysis reactor (200), the pressure from the back pressure regulator Vapor methanol is condensed and stored in methanol storage (30); crystallization tank (400), which is used to crystallize DMT from the liquid in rectification column (300); solid-liquid separator (500), which is used to separate Crystallized DMT; a distillation column (600) for separating methanol in its upper part from EG-rich liquid methanol to store the separated methanol in a methanol reservoir (30) and in its lower part from EG-rich liquid methanol Oligomers are separated from the liquid methanol of EG to recycle the separated oligomers to the first reactor (100).

In addition, the device of the present invention may also include a waste receptacle between the raw material feeder (10) and the first reactor (100), which is used to weigh the raw material supplied by the raw material feeder and transfer the weighed Raw materials are supplied to the reactor.

In addition, the transfer pipe (70a) for transferring to the second reactor (200) is also equipped with a sensor for detecting the liquid level in the second reactor (200), and using the sensor to detect the liquid level and adjust the liquid level A liquid level controller to automatically open the valve (80a) when the liquid level drops.

The pressure in the second reaction ( 200 ) and rectification column ( 300 ) can be adjusted by manipulating a portion of the methanol exiting the top of the rectification column using a back pressure regulator ( 31 ) or other pressure regulating valve.

In addition, it is preferable that a condenser for condensing methanol is also configured on the upper part of the methanol storage (30), so that part of the methanol is collected into the methanol storage when the amount of methanol discharged through the top of the rectification column (30) is too much (30).

Then, the present invention provides a method of recycling polyester raw materials such as DMT and EG from PET by partial glycolysis and methanolysis and purification.

Specifically, the method for recycling polyester raw materials such as DMT and EG from polyester waste according to the present invention includes: charging the raw materials and a predetermined amount of EG or a mixture of oligomers and depolymerization catalysts from a distillation column (600) into the first reactor (100), and by continuously supplying methanol to increase the pressure in the reactor so that the feedstock is depolymerized; when the depolymerization is completed, the transfer pipe (70a) connected to the second reactor (200) is opened The transfer valve (80a) to transfer the reactant from the first reactor (100); the gaseous reaction product generated in the second reactor (200) is transferred to the rectification column (300), and separated in the upper part of the column pure methanol and liquefy the remaining methanol, DMT and EG in the lower part of the column; recycle the methanol separated in the upper part of the rectification column (300) to the second reactor (200) and store a part of the methanol In the methanol storage tank (30); the liquid that flows out from the lower part of the rectification column (300) is transferred to the crystallization tank (400) so that DMT is crystallized; the product from the crystallization tank (400) is transferred to the solid-liquid separator ( 500) to separate DMT crystals and EG-rich liquid methanol; transfer the EG-rich liquid methanol to a distillation column (600) to separate EG, oligomers and methanol, and store the methanol in a methanol storage ( 30), the oligomers are recycled to the first reactor (100).

The first reactor (100) and the second reactor (200) are connected by a transfer pipe (70a), so that the reactants are transferred by pressure difference. More specifically, when the liquid level in the second reactor (200) drops, the transfer valve (80a) of the transfer pipe (70a) is automatically opened, and the reactant is transferred from the first reactor (100) to the second reactor through the pressure difference. Two reactors (200).

In addition, the first reactor (100) operates at a temperature of 200°C to 300°C and a reaction pressure from atmospheric pressure to 50 bar, and the second reactor (200) operates at a temperature of 200°C to 300°C and a reaction pressure from atmospheric pressure to 10 bar, The reactants can thus be transported automatically.

In addition, EG separated in the distillation column (600) can be used as a raw material that can be charged into the first reactor (100).

More specifically, the raw material used in the process of the present invention is polyester waste and is fed into the first reactor (100) through a raw material feeder (10) such as an extruder, screw feeder and airlock valve. Polyester waste can be fed in solid form ranging from powder to flakes with suitable dimensions, or in molten form. The first reactor (100) can be operated in continuous, semi-continuous or batch mode, and by using the reactor with a large molecular weight polyester, it can be depolymerized into BHET, MHET or oligomerization with a significantly reduced molecular weight through glycolysis. thing.

Furthermore, since the methanolysis reaction is carried out in parallel with the glycolysis reaction, a considerable amount of DMT is produced in the first reactor (100). In this process, since the EG generated by methanolysis can be used again for glycolysis, the two reactions show synergy with each other. In addition, the generated EG itself can be used to dissolve the newly supplied PET raw material, so the amount of EG required for glycolysis can be significantly reduced, or no EG needs to be fed.

When the EG comprising catalyst and oligomers is fed into the first reactor (100), the glycolysis reaction and the methanolysis reaction occur simultaneously to obviously consume polyester waste, thus in the second reactor ( 200) the subsequent conversion to DMT and EG tends to occur rapidly. The pressure of the first reactor (100) can be adjusted by adjusting the amount of methanol sent from the methanol storage (30) to the first reactor (100) through the transfer pipe (120b).

The first reactor (100) and the second reactor (200) are connected by a transfer pipe (70a), so that reactants are transferred by pressure difference. More specifically, when the liquid level in the second reactor (200) drops, the transfer valve (80a) of the transfer pipe (70a) is automatically opened, and the reactant is transferred from the first reactor (100) to the second reactor through the pressure difference. Two reactors (200).

For the second reactor (200) of the present invention, methanol is sent to the lower part of the reactor through the bubble generator (90). The methanolysis reaction occurs while the methanol sent to the lower part and the reactants delivered from the first reactor (100) are in direct contact with each other, whereby gaseous reaction products are discharged through the top of the second reactor (200). In this process, methanol functions not only as a reaction material, but also as a carrier to allow the reaction products to be discharged together with the methanol vapor itself.

While the transfer valve (80b) of the transfer pipe (70b) is opened, the reaction product produced in the second reactor (200) is transferred to the rectification column (300), and is mixed with the liquid, i.e. the solution of DMT, EG and methanol The bottom of the distillation column (300) is in contact. Therefore, only methanol is separated at the top of the column, while methanol, DMT and EG are liquefied in the lower part of the column, which makes the subsequent crystallization process more favorable. Methanol separation is accomplished as the downflowing liquid contacts the upflowing gaseous methanol in trays or packing while the feed methanol is supplied for reflux. Using the above process can improve the separation efficiency of methanol and other products.

Methanol vapor is recovered at the top of the rectification tower (300), and most of the recovered methanol vapor is recycled to the low-pressure continuous methanolysis reactor, namely the second reactor (200), through a compressor (61) or a blower.

The pressure in the second reactor (200) and the rectification column (300) can be adjusted by regulating the outflow of part of the methanol vapor recovered at the top of the rectification column (300) using a back pressure regulator (31) or other pressure regulating valves . In addition, when the amount of methanol discharged from the top of the rectification column (300) is too much, part of the methanol vapor can flow out through the back pressure regulator (31) and be condensed and stored in the methanol storage tank (30).

Therefore, the present invention saves a lot of energy compared to the existing method, which evaporates the raw methanol supplied by the methanol storage (30) and sends the evaporated methanol to the depolymerization reactor. In addition, with recovery of methanol at the top of rectification column (300), DMT and EG are concentrated in the lower part of rectification column (300), which facilitates the subsequent crystallization process.

The DMT and EG flowing out from the rectification tower (300) are transported to the crystallization tank (400) for the crystallization process. DMT is crystallized by concentration or cooling, and then moved to a solid-liquid separator (500). In the solid-liquid separator, use a centrifuge or filter to separate DMT crystals and EG-enriched liquid methanol. The advantage of DMT obtained through the above process is that the recovery efficiency of DMT is quite high, and high purity can be obtained.

EG-enriched liquid methanol is a liquid containing excess EG and methanol, which also contains small amounts of oligomers.

Subsequently, the EG-enriched liquid methanol is transferred to a distillation column (600) for a subsequent separation process to separate into EG, oligomers and methanol. At this time, the distillation column (600) can be operated continuously or batchwise. The methanol separated in the distillation column (600) is stored in the methanol storage (30), the oligomers can be recycled to the first reactor (100) via the transfer pipe (130), and the EG is stored in the EG storage.

beneficial effect

According to the present invention, DMT and EG are liquefied by bringing the methanolysis product from the methanolysis reactor (200) into direct contact with the liquid pool at the bottom of the column and evaporating the methanol from the methanol reservoir as reflux in the rectification column (300) The raw material methanol of product, thereby can separate gaseous methanol in rectifying column (300). In addition, since the gaseous methanol separated in the rectification tower is recycled to the second reactor (200) via the recycle compressor (61) or blower, and passes through the bubble generator (90) at the lower part of the second reactor (200) in the reaction The interior of the reactor is in direct contact with the polyester solution for the methanolysis reaction, which can significantly save the energy cost caused by repeated evaporation and liquefaction in the existing methanol recycling process. In addition, since it is not necessary to use the methanol evaporator, heater and high-pressure pump used in the existing methanol recycling process, the installation can be simplified and the installation cost can be significantly saved.

In addition, by adjusting the pressure in the second reactor (200) and the rectification column (300) by manipulating the gas flowing out from the upper part of the rectification column (300), the reaction conditions and rectification conditions can be adjusted freely, and by introducing The crystallization tank (400) and the solid-liquid separator (500) can also obtain high monomer recovery efficiency and high-purity monomer DMT.

Description of drawings

Fig. 1 is a schematic diagram showing an apparatus for recycling raw materials from polyester waste.

Detailed description of main components

10: Raw material feeder

30: methanol storage

31: Back pressure regulator

61: Cycle compressor

90: Bubble generator

100: first reactor

200: second reactor

300: Distillation tower

400: Crystallization tank

500: solid-liquid separator

600: Distillation tower

70a, 70b, 110a, 120a, 120b, 130: transfer tubes

80a, 80b: Transfer valves

Detailed ways

The apparatus and method for recycling raw materials from polyester waste will be described in detail below.

First, raw materials such as polyester waste are put into the raw material feeder (10), and then sent into the first reactor (100). The raw material feeder (10) is a raw material supplier, which can be an extruder, a screw feeder or an air lock valve, but is not limited thereto. Polyester waste can be fed in solid form ranging from powder to flakes with suitable dimensions, or in molten form. The first reactor (100) can operate in a continuous, semi-continuous or batch type. A predetermined amount of EG and methanol are injected into the first reactor (100) to cause a depolymerization reaction, and if necessary, oligomers separated in the distillation column (600) may be put into the first reactor (100) to Reacted. After the temperature of the reactor is raised to the required temperature, the raw methanol is supplied to the first reactor (100) from the methanol storage (30) through the transfer pipe (120b), so that the pressure in the reactor reaches the required reaction pressure . At this time, methanol was continuously fed to maintain a constant pressure in the reactor. Since the glycolysis reaction and the methanolysis reaction in the first reactor (100) occur simultaneously under high pressure, the molecular weight of the polyester waste material is significantly reduced, and thus the polyester waste material becomes a solution state of DMT and oligomers.

In the continuous second reactor (200) at low pressure, the reactants transferred from the first reactor (100) via the transfer pipe (70a) and transfer valve (80a) are generated with the bubbles from the rectification column (300) The methanol supplied by the reactor (90) reacts in the lower part of the second reactor (200) to produce methanolysis reaction. The reaction product is discharged in gaseous phase through a transfer pipe (70b) connected to the top of the reactor and a transfer valve (80b). Thus, a predetermined amount of reactant is delivered from the first reactor (100) when the liquid level in the second reactor (200) is lowered. In this case, the transfer takes place automatically via the differential pressure. It is preferable that the valve is arranged on the lower part of the transfer pipe (70a) to control the liquid level of the reaction liquid inside the second reactor (200), and the controller can be connected with the valve (80a) of the transfer pipe so that the valve passes through the controller. And run automatically.

When the first reactor (100) is operated in batch mode, the first reactor (100), which transfers reactants to the second reactor (200), is charged with solid polyester waste and fed with oligomers and EG solution and methanol, so that a new batch reaction can be started by repeating the above process.

That is, polyester waste is converted into DMT and oligomers in the first reactor (100) by high pressure reaction, and gaseous DMT, EG, oligomers and oligomers are continuously discharged from the second reactor (200) by methanolysis. Methanol. At this time, when the liquid level in the second reactor (200) drops, the reactant in the first reactor (100) is transferred to the second reactor (200) again to meet the required liquid level, and A new batch process starts in reactor (100).

At the same time, the gaseous reaction product discharged from the second reactor (200) is transferred to the rectification column (300) through the transfer pipe (70b), and directly contacts with the liquid pool at the lower part of the rectification column (300) to liquefy DMT and EG and evaporate Methanol. Since methanol and other products are separated by this direct contact, significant energy savings can be achieved.

In addition, raw methanol is injected into the upper part of the rectification column (300) to reflux, and the liquid stream and the gaseous stream of the reaction product contact each other in trays or packing sections to separate methanol only through the top of the column. The separated methanol vapor is injected into the second reactor (200) using a recycle compressor (61) or blower connected to the rectification column (300). Afterwards, the methanol contacts the polyester solution inside the second reactor (200) through the bubble generator (90) to generate methanolysis reaction.

In addition, when the amount of methanol discharged through the top of the rectifying tower (300) is too much, use a back pressure regulator (31) or other pressure regulating valves to let part of the methanol gas flow out to adjust the second reactor (200) and the rectifying reactor (200). The pressure in the distillation column (300) and stored in the methanol storage (30) after condensation.

On the contrary, when the amount of methanol sent into the second reactor (200) should be increased, more methanol in the methanol storage (30) is sent to the upper part of the rectification column (300) and evaporated to be sent to the second reactor (200). Reactor (200). The concentration of DMT at the bottom of the rectification column (300) can be adjusted by adjusting the temperature of the lower part of the rectification column. The temperature can be controlled by adjusting the injection rate (return rate) of the raw material methanol sent to the upper part of the rectification column (300) through the transfer pipe (120a) from the methanol storage (30), and in consideration of the recirculation flow rate or circulation of methanol gas The heating amount of the lower part of the rectification column (300) can be determined at the flow rate.

The DMT and EG-rich methanol solution liquefied in the lower part of the rectification column (300) are transferred to the crystallization tank (400). DMT is crystallized by evaporative cooling, and the DMT and EG-rich liquid methanol are separated in a solid-liquid separator (500) arranged adjacent to the crystallization tank (400). Subsequently, the EG-enriched liquid methanol is transferred to a distillation column (600) and separated into EG, methanol and some oligomers. The separated methanol is stored in the methanol storage (30) and the EG is collected. In addition, the oligomers obtained at the bottom of the distillation column (600) are sent to the first reactor (100) for depolymerization again.

Although the invention has been described with respect to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention as defined in the claims.

Claims (15)

1. by a device for polyester waste material recirculation raw material, described device makes polyester raw material dimethyl terephthalate (DMT) and ethylene glycol by polyester waste material, and described device comprises:

Raw material feeder (10);

The first reactor (100), described the first reactor (100) is used by the described raw material of described raw material feeder (10) supply and in single reaction vessel, carries out glycolysis reaction and methyl alcohol alcoholysis reaction;

The second reactor (200), described the second reactor (200) carries out methyl alcohol alcoholysis reaction for the product that makes described the first reactor (100);

Rectifying tower (300), described rectifying tower (300) makes the product of discharging from top by described the second reactor (200) with described rectifying tower (300) thereby the liquid cell of bottom directly contact direct liquefaction dimethyl terephthalate (DMT) and ethylene glycol and evaporates also separation of methanol separately, and makes separated gaseous methanol be recycled to described the second reactor (200); With

Methanol storage device (30), described methanol storage device (30) is for providing methyl alcohol to described rectifying tower (300).

2. device as claimed in claim 1, wherein said rectifying tower (300) is by the methyl alcohol separating in the product by described the second reactor (200) and provide the mixture of the methyl alcohol that need reflux and evaporate to the top of described rectifying tower (300) to be recycled to described the second reactor (200) by described methanol storage device (30).

3. device as claimed in claim 1, described device also comprises that back pressure type setter (31) is to control the pressure of described methyl alcohol alcoholysis reaction device (200) and described rectifying tower (300).

4. the device as described in any one in claim 1～3, described device also comprises crystallizer tank (400), described crystallizer tank (400) is for making the liquid crystallization of dimethyl terephthalate (DMT) from described rectifying tower (300).

5. device as claimed in claim 4, described device also comprises solid-liquid separator (500), described solid-liquid separator (500) is for separating of the dimethyl terephthalate (DMT) of institute's crystallization.

6. device as claimed in claim 5, described device also comprises the distillation tower (600) being connected with described solid-liquid separator (500), and described distillation tower is for isolating methyl alcohol the methyl alcohol being separated be stored in described methanol storage device (30) and isolate oligopolymer so that the oligopolymer being separated is recycled in described the first reactor (100) in its underpart from be rich in the liquid methanol of ethylene glycol from being rich in the liquid methanol of ethylene glycol at an upper portion thereof.

7. device as claimed in claim 1, described device also between described raw material feeder (10) and described the first reactor (100), comprise waste material in storage, in described waste material storage for weigh the raw material that provided by described raw material feeder and by the raw material supply through weighing to described reactor.

8. device as claimed in claim 1, described device also comprises sensor, described sensor is for the liquid level in the transfer tube (70a) in order to transfer to described the second reactor (200) detects described the second reactor (200).

9. device as claimed in claim 8, described device is also included in the valve (80a) being connected with described sensor in described the second reactor (200), and described valve is automatically opened when the liquid level being detected by described sensor reduces.

10. device as claimed in claim 1, wherein said the second reactor (200) comprises bubble generator (90), described bubble generator (90) is the methyl alcohol through evaporation from described rectifying tower (300) for supply.

11. 1 kinds of methods by polyester waste material recirculation raw material, described method makes polyester raw material dimethyl terephthalate (DMT) and ethylene glycol by polyester waste material, and described method comprises:

The mixture of the ethylene glycol of raw material and predetermined amount and depolymerization catalyzer is packed in the first reactor (100), thereby and the pressure increasing in described reactor by methyl alcohol without interruption make described raw material depolymerization;

The transmission valve (80a) of opening the transfer tube (70a) being connected with the second reactor when depolymerization completes is to transmit the reactant from described the first reactor (100);

The gaseous reaction products generating in described the second reactor (200) is transferred to rectifying tower (300), directly contact with the separation pure methyl alcohol in the top at described tower liquefy in the bottom of described tower remaining methyl alcohol, dimethyl terephthalate (DMT) and ethylene glycol with the liquid cell of rectifier bottoms;

The methyl alcohol separating on the top of described rectifying tower (300) is recycled to described the second reactor (200) and a part for described methyl alcohol is stored in methanol storage device (30);

The fluid transport that will flow out from the bottom of described rectifying tower (300) is to crystallizer tank (400) so that dimethyl terephthalate (DMT) crystallization;

To from the product of described crystallizer tank (400), transfer to solid-liquid separator (500) with terephthalic acid isolated dimethyl ester crystal and the liquid methanol that is rich in ethylene glycol; With

The described liquid methanol that is rich in ethylene glycol is transferred to distillation tower (600) with separating ethylene glycol, oligopolymer and methyl alcohol, and described methyl alcohol is stored in described methanol storage device (30), described oligopolymer is recycled to described the first reactor (100).

12. methods as claimed in claim 11, wherein said the first reactor (100) with described the second reactor (200) through transfer tube (70a) thus be connected described reactant transmitted by pressure reduction.

13. methods as claimed in claim 11, wherein said the first reactor (100) moves to the reaction pressure of 50bar in temperature and the normal atmosphere of 200 ℃～300 ℃, and described the second reactor (200) moves in temperature and normal atmosphere to the reaction pressure of 10bar of 200 ℃～300 ℃.

14. methods as claimed in claim 11, wherein when the liquid level in described the second reactor (200) reduces, the transmission valve (80a) of described transfer tube (70a) is opened automatically, and described reactant transfers to described the second reactor (200) by pressure reduction from described the first reactor (100).

15. methods as claimed in claim 11, the ethylene glycol wherein separating in described distillation tower (600) can be as the raw material packing in described the first reactor (100).