Feeding device and B-grade PET regeneration system and process

Abstract

The invention relates to the technical field of polyester preparation, in particular to a feeding device and a B-grade PET regeneration system and technology.The feeding device comprises a stock bin, a batching kettle, a raw material feeding mechanism and a mixed material discharging mechanism, the stock bin is used for storing B-grade products, and a discharging port of the stock bin is communicated with a first feeding port of the batching kettle through a pipeline; a feeding pipeline of the raw material feeding mechanism is connected between a raw material conveying pipeline on the product production line and a second feeding hole of the batching kettle; a discharging pipeline of the mixed material discharging mechanism is connected between the mixed material outlet of the batching kettle and the raw material conveying pipeline, and the connecting position of the discharging pipeline and the raw material conveying pipeline is located at the downstream of the connecting position of the feeding pipeline and the raw material conveying pipeline. According to the feeding device, B-grade products which do not meet the requirements of A-grade products are fed back to a production line again, so that the purposes of reducing cost and improving efficiency are achieved; and the raw materials are used as conveying media to convey the B-grade products, and the stability and safety of the production line can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of polyester preparation, and in particular to a feeding device, a B-grade PET regeneration system and a process. Background Art

[0002] Polyethylene terephthalate (PET) is a thermoplastic polyester material with a glass transition temperature (Tg) between 70-90°C and a melting point of 250-265°C. It undergoes depolymerization under the action of heat and chemical reagents to produce low molecular weight products such as terephthalic acid (TPA), methyl terephthalate (DMT), polyethylene terephthalate (BHET), ethylene glycol (EG) and other monomers or other chemicals.

[0003] At present, a polyester factory produces about 5,000 tons of B-grade PET products every year on its annual production line with an annual output of one million tons of PET. The molecular weight, color, melting point, etc. of this product do not meet the standards of A-grade products. Direct disposal will lead to increased production costs and reduced production efficiency.

[0004] Therefore, how to recycle Class B PET products has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] The first purpose of the present invention is to provide a feeding device to solve the technical problem that the B-grade products produced on the production line in the prior art do not meet the standards of the A-grade products, and direct disposal will lead to increased production costs and reduced production efficiency.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A feeding device comprises a silo, a batching kettle, a raw material feeding mechanism and a mixing and discharging mechanism, wherein:

[0008] The silo is used to store the Class B product produced during the production process of the product, and the discharge port of the silo is connected to the first feed port of the batching kettle through a pipeline;

[0009] The raw material feeding mechanism comprises a feeding pipeline, and the feeding pipeline is connected between the raw material conveying pipeline on the product production line and the second feeding port of the batching kettle;

[0010] The mixing and discharging mechanism comprises a discharging pipeline, which is connected between the mixing outlet of the batching kettle and the raw material conveying pipeline, and the connection position of the discharging pipeline and the raw material conveying pipeline is located downstream of the connection position of the feeding pipeline and the raw material conveying pipeline.

[0011] Furthermore, the raw material feeding mechanism also includes a spray module arranged on the feeding pipeline.

[0012] Furthermore, it also includes an exhaust gas recovery mechanism, which includes an exhaust gas pipeline and an exhaust gas sealing tank, and the exhaust gas pipeline is connected between the exhaust gas sealing tank and the exhaust gas outlet of the spray module.

[0013] Furthermore, the mixing and discharging mechanism further comprises a kettle bottom sampling valve and / or a discharging valve and / or a centrifugal pump arranged on the discharging pipeline;

[0014] And / or, the discharge pipeline is provided with an emptying branch, and the emptying branch is provided with an emptying valve.

[0015] Furthermore, it also includes a purge mechanism, which includes a purge pipeline, a purge gas storage tank and a purge valve, wherein the purge pipeline is connected between the purge gas storage tank and the batching kettle, and the purge valve is arranged on the purge pipeline;

[0016] And / or, it also includes a flushing mechanism, which includes a flushing pipeline, a flushing liquid storage tank and a purge valve, wherein the flushing pipeline is connected between the flushing liquid storage tank and the discharge pipeline, and the purge valve is arranged on the flushing pipeline.

[0017] Furthermore, it also includes a purge mechanism, which includes a purge pipeline and a distributor, wherein:

[0018] The inlet of the purge pipeline is used to input the purge gas, and the outlet of the purge pipeline is connected to the inlet of the distributor;

[0019] The distributor is arranged in the batching kettle and located at the bottom of the batching kettle, and a plurality of outlets distributed at intervals are arranged on the distributor.

[0020] Furthermore, it also includes a liquid level gauge arranged on the side wall of the batching kettle;

[0021] The raw material feeding mechanism also includes a flow regulating valve arranged on the feeding pipeline, and the flow regulating valve is interlocked with the liquid level meter for control.

[0022] Furthermore, it also includes a diverter valve, which includes a valve main pipe, a connecting pipe, a valve branch pipe and a piston column, wherein:

[0023] The valve main pipe is connected in series with the raw material conveying pipeline;

[0024] One end of the connecting pipe is connected to the side wall of the valve main pipe, and the piston rod is slidably inserted into the connecting pipe from the other end of the connecting pipe;

[0025] One end of the valve branch pipe is connected to the side wall of the connecting pipe, and the other end of the valve branch pipe is connected to the feed pipeline or the discharge pipeline;

[0026] The valve main pipe, the connecting pipe and the valve branch pipe are connected in sequence.

[0027] The second object of the present invention is to provide a B-grade PET regeneration system, the system comprising a raw material preparation tank, a preparation device, a raw material conveying pipeline and any of the above-mentioned feeding devices, wherein:

[0028] The raw material preparation tank is used to store the raw materials for producing PET products;

[0029] The preparation device is used to process the raw material into a PET product;

[0030] The raw material conveying pipeline is connected between the raw material preparation tank and the preparation device.

[0031] The third object of the present invention is to provide a B-grade PET regeneration process, which is applied to the above-mentioned B-grade PET regeneration system and comprises the following steps:

[0032] Feeding part of the raw materials in the raw material conveying pipeline into the batching kettle through the feed pipeline;

[0033] Feeding the Class B product in the silo into the batching kettle;

[0034] The raw materials and the Class B product mixed in the batching kettle are sent into the raw material conveying pipeline through the discharge pipeline.

[0035] Beneficial effects of the present invention:

[0036] The present invention provides a feeding device, a B-grade PET regeneration system and a process. The feeding device comprises a silo, a batching kettle, a raw material feeding mechanism and a mixing and discharging mechanism, wherein: the silo is used to store the B-grade product generated in the production process of the product, and the discharge port of the silo is connected with the first feed port of the batching kettle through a pipeline; the raw material feeding mechanism comprises a feeding pipeline, which is connected between a raw material conveying pipeline on the product production line and the second feed port of the batching kettle; the mixing and discharging mechanism comprises a discharging pipeline, which is connected between the mixing outlet of the batching kettle and the raw material conveying pipeline, and the connection position of the discharging pipeline and the raw material conveying pipeline is located downstream of the connection position of the feeding pipeline and the raw material conveying pipeline.

[0037] The feeding device, B-grade PET regeneration system and process provided by the present application have at least the following advantages:

[0038] 1. Return the Class B products that do not meet the requirements of Class A products to the production line to transform them into Class A products with higher economic value, thereby achieving the goal of reducing costs and increasing efficiency;

[0039] 2. Using raw materials as the conveying medium to convey Class B products can achieve the purpose of intermittent addition of Class B products on the original continuous production line, so that the production line can adapt to the production change in time and improve the stability and safety of the production line;

[0040] 3. The setting of the feeding device does not change the overall flow direction of the raw material conveying pipeline, has little impact on the continuous production process, and is conducive to the stable and safe operation of the production line;

[0041] 4. The process is simple, the operation is convenient, and the applicability is high. It can be widely used in product production lines with slurry or powder as raw materials;

[0042] 5. Raw materials and Class B products are mixed in a certain proportion in the batching kettle to ensure the quality of the final product. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 A schematic diagram of the structure of a Class B PET regeneration system provided by one embodiment of the present invention;

[0045] Figure 2 A schematic structural diagram of a Class B PET regeneration system provided by another embodiment of the present invention;

[0046] Figure 3 A schematic diagram of the structure of a distributor provided in an embodiment of the present invention;

[0047] Figure 4 A cross-sectional schematic diagram of a diverter valve provided in an embodiment of the present invention.

[0048] icon:

[0049] 1- Silo;

[0050] 2- batching kettle; 21- first feed inlet; 22- second feed inlet; 23- mixing outlet; 24- air inlet;

[0051] 3-Raw material feeding mechanism; 31-Feeding pipeline; 32-Spraying module; 33-Flow regulating valve;

[0052] 4-mixing and discharging mechanism; 41-discharging pipeline; 42-bottom sampling valve; 43-discharging valve; 44-centrifugal pump; 45-draining branch; 46-draining valve;

[0053] 5-waste gas recovery mechanism; 51-waste gas pipeline; 52-waste gas sealing tank;

[0054] 6-purge mechanism; 61-purge pipeline; 62-purge gas storage tank; 63-purge valve; 64-distributor;

[0055] 7-flushing mechanism; 71-flushing pipeline; 72-flushing liquid storage tank; 73-flushing valve;

[0056] 8-Liquid level gauge;

[0057] 9- diverter valve; 91- valve main pipe; 92- connecting pipe; 93- valve branch pipe; 94- piston rod; 95- knob;

[0058] 10-Star type discharger;

[0059] 100-Raw material conveying pipeline. DETAILED DESCRIPTION

[0060] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] It should be noted that in the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0062] It should be noted that in the description of the present invention, the terms "connection" and "installation" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or connected through an intermediate medium; it can be a mechanical connection or an electrical connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] The first aspect of the present invention provides a feeding device, referring to Figure 1The feeding device includes a silo 1, a batching kettle 2, a raw material feeding mechanism 3 and a mixing and discharging mechanism 4, wherein:

[0064] The silo 1 is used to store the Class B product produced during the production process of the product, and the discharge port of the silo 1 is connected to the first feed port 21 of the batching kettle 2 through a pipeline;

[0065] The raw material feeding mechanism 3 includes a feeding pipeline 31, and the feeding pipeline 31 is connected between the raw material conveying pipeline 100 on the product production line and the second feeding port 22 of the batching kettle 2;

[0066] The mixing and discharging mechanism 4 includes a discharging pipeline 41 , which is connected between the mixing outlet 23 of the batching kettle 2 and the raw material conveying pipeline 100 , and the connection position of the discharging pipeline 41 and the raw material conveying pipeline 100 is located downstream of the connection position of the feeding pipeline 31 and the raw material conveying pipeline 100 .

[0067] It should be noted that the B-grade products described in this application are products that do not meet the standards of A-grade products. B-grade products and A-grade products are relative and there is no strict definition requirement. B-grade products can also be called inferior products, defective products or substandard products. The criteria for determining B-grade products can be adjusted according to actual production needs and are not limited here.

[0068] Taking the application of the above-mentioned feeding device in the PET product production line as an example, the working principle of the feeding device is: during the production process, the raw material conveying pipeline 100 conveys the raw materials for producing PET products to the preparation device; part of the raw materials in the raw material conveying pipeline 100 enters the batching kettle 2 through the feeding pipeline 31, and after being mixed with the Class B (PET) product in the batching kettle 2, it returns to the raw material conveying pipeline 100 through the discharge pipeline 41; subsequently, the Class B (PET) product is conveyed to the esterification kettle with the help of the raw material slurry, and then melts and EG alcoholyzes under high temperature conditions. The product passes through the pre-condensation, intermediate condensation, solid phase condensation and other stages in sequence with the BHET slurry, and is finally transformed into a Class A PET product with higher economic value.

[0069] The feeding device provided in this application has at least the following advantages:

[0070] 1. Return the Class B products that do not meet the requirements of Class A products to the production line to transform them into Class A products with higher economic value, thereby achieving the goal of reducing costs and increasing efficiency;

[0071] 2. Using raw materials as the conveying medium to convey Class B products can achieve the purpose of intermittent addition of Class B (PET) products on the original continuous (PET) production line, so that the production line can adapt to the production change in time and improve the stability and safety of the production line;

[0072] 3. The setting of the feeding device does not change the overall flow direction of the raw material conveying pipeline 100, has little impact on the continuous production of PET process, and is conducive to the stable and safe operation of the production line;

[0073] 4. The process is simple, the operation is convenient, and the applicability is high. It can be applied to other product production lines (i.e. non-PET product production lines) whose raw materials are slurry or powder;

[0074] 5. The raw materials and Class B products are mixed in a certain proportion in batching kettle 2 to ensure the quality of the final product.

[0075] As an optional embodiment, a star-shaped discharger 10 is provided at the discharge port of the silo 1 , and the amount of the Class B product entering the batching kettle 2 can be controlled by the star-shaped discharger 10 .

[0076] As an optional embodiment, the raw material feeding mechanism 3 further includes a spray module 32 disposed on the feeding pipeline 31. Specifically, the inlet of the spray module 32 is connected to the raw material conveying pipeline 100 through the feeding pipeline 31, and the outlet at the bottom of the spray module 32 is connected to the second feeding port 22 to spray the floating dust generated by the solid material entering the batching kettle 2. The exhaust gas outlet at the top of the spray module 32 is used to discharge the exhaust gas produced during the spraying process.

[0077] On the basis of the above structure, the feeding device further includes an exhaust gas recovery mechanism 5, which includes an exhaust gas pipeline 51 and an exhaust gas sealing tank 52, wherein the exhaust gas pipeline 51 is connected between the exhaust gas sealing tank 52 and the exhaust gas outlet of the spray module 32. The exhaust gas discharged from the exhaust gas outlet of the spray module 32 enters the exhaust gas sealing tank 52 along the exhaust gas pipeline 51.

[0078] Continue to refer to Figure 1 The feeding device further includes a liquid level meter 8 disposed on the side wall of the batching kettle 2; the raw material feeding mechanism 3 further includes a flow regulating valve 33 disposed on the feeding pipeline 31, and the flow regulating valve 33 is interlocked with the liquid level meter 8. Specifically, a liquid level meter socket for inserting the liquid level meter 8 is disposed on the side wall of the batching kettle 2, and the height of the liquid level meter socket can be adjusted according to actual needs to monitor the liquid level in the batching kettle 2 in real time; the liquid level meter 8 is interlocked with the flow regulating valve 33 on the feeding pipeline 31, and the liquid level in the batching kettle 2 is controlled by controlling the feed flow rate.

[0079] Further, Figure 2 The embodiment shown is Figure 1 The expansion scheme of the embodiment shown, refer to Figure 2 The mixing and discharging mechanism 4 further includes a kettle bottom sampling valve 42 and / or a discharging valve 43 and / or a centrifugal pump 44 arranged on the discharging pipeline 41;

[0080] And / or, the discharge pipeline 41 is provided with an emptying branch 45 , and the emptying branch 45 is provided with an emptying valve 46 .

[0081] Figure 2 In the illustrated embodiment, the mixing and discharging mechanism 4 further includes a bottom sampling valve 42, a discharging valve 43, a centrifugal pump 44 and an emptying branch 45, wherein the bottom sampling valve 42, the emptying branch 45, the discharging valve 43 and the centrifugal pump 44 are sequentially arranged on the discharging pipeline 41 from the batching kettle 2 to the raw material conveying pipeline 100, and the emptying branch 45 is provided with an emptying valve 46. In the above structure, the bottom sampling valve 42 is used to introduce the mixed material discharged from the mixing outlet 23 into the discharging pipeline 41; the emptying branch 45 is used to empty the batching kettle 2; the discharging valve 43 can be specifically a ball valve, which cooperates with the centrifugal pump 44 to pressurize the mixed material in the batching kettle 2 and convey it to the raw material conveying pipeline 100.

[0082] As an optional embodiment, in order to maintain the temperature of the raw material slurry, an insulation layer is provided around the pipeline for conveying the raw material slurry for insulation.

[0083] As an optional embodiment, the feeding device further includes a purge mechanism 6, which includes a purge pipeline 61, a purge gas storage tank 62 and a purge valve 63, wherein the purge pipeline 61 is connected between the purge gas storage tank 62 and the batching kettle 2, and the purge valve 63 is arranged on the purge pipeline 61. Specifically, an air inlet 24 is arranged at the top of the batching kettle 2, and one end of the purge pipeline 61 away from the purge gas storage tank 62 extends into the batching kettle 2 through the air inlet 24 to purge the batching kettle 2 to avoid the problem of pipeline blockage that may occur during production.

[0084] Based on the above structure, nitrogen is specifically stored in the purge gas storage tank 62. In other embodiments, the purge gas may also be other gases besides nitrogen.

[0085] Furthermore, the purge mechanism 6 further includes a distributor 64, wherein:

[0086] The inlet of the purge pipeline 61 is used to input the purge gas, and the outlet of the purge pipeline 61 is connected to the inlet of the distributor 64;

[0087] The distributor 64 is disposed in the batching kettle 2 and located at the bottom of the batching kettle 2 . The distributor 64 is provided with a plurality of outlets distributed at intervals.

[0088] Specifically, combined Figure 3The distributor 64 includes an annular body and a plurality of gas outlets arranged on the annular body, wherein the plurality of gas outlets are arranged at intervals along the circumference of the annular body, and the gas outlets face the bottom wall of the batching kettle 2. The purge pipeline 61 enters the batching kettle 2 through the air inlet 24, is inserted straight along the kettle wall to the bottom of the kettle and is connected to the inlet of the distributor 64. When the outlet section at the bottom of the batching kettle 2 is blocked, the blockage problem can be solved by the purge mechanism 6, specifically: close the star discharger 10, the flow regulating valve 33, the agitator on the batching kettle 2 and the discharge valve 43, open the emptying valve 46 and the purge valve 63, and allow nitrogen to enter the distributor 64 along the purge pipeline 61; the distributor 64 can blow the gas to the bottom of the batching kettle 2 in the form of an annular airflow, and then purge the blocked position at the bottom of the kettle with nitrogen, and the generated residue can be removed through the emptying branch 45.

[0089] As an optional embodiment, the feeding device also includes a flushing mechanism 7, which includes a flushing pipeline 71, a flushing liquid storage tank 72 and a purge valve 73, wherein the flushing pipeline 71 is connected between the flushing liquid storage tank 72 and the discharge pipeline 41, and the purge valve 73 is arranged on the flushing pipeline 71.

[0090] Specifically, the connection position of the flushing pipeline 71 and the discharge pipeline 41 coincides with the connection position of the emptying branch 45 and the discharge pipeline 41, or the connection position of the flushing pipeline 71 and the discharge pipeline 41 is located between the connection position of the emptying branch 45 and the discharge pipeline 41 and the mixing outlet 23 of the batching kettle 2; ethylene glycol solution can be stored in the flushing liquid storage tank 72.

[0091] When the outlet section at the bottom of the batching kettle 2 is clogged, the flushing mechanism 7 can be used to solve the clogging problem. Specifically, first close the drain valve 46, the star discharger 10, the flow regulating valve 33, the agitator on the batching kettle 2 and the discharge valve 43, open the purge valve 73, and allow the ethylene glycol solution to flush the blocked position at the bottom of the kettle along the flushing pipeline 71; after the flushing is completed, close the purge valve 73, open the drain valve 46, and drain the residual liquid in the kettle. The above operation can be repeated until the clogging problem is solved, so that the raw material slurry containing the Class B product can flow smoothly along the discharge pipeline 41.

[0092] For the embodiment in which both the purge mechanism 6 and the flushing mechanism 7 are provided, when the bottom outlet section of the batching kettle 2 is blocked, the blockage can be relieved by either the purge mechanism 6 or the flushing mechanism 7, or the two can be combined to relieve the blockage. When the purge mechanism 6 and the flushing mechanism 7 are combined to relieve the blockage, the flushing mechanism 7 can be used to reversely flush the bottom outlet section of the batching kettle 2 first, and then the purge mechanism 6 can be used to empty the batching kettle 2.

[0093] Reference Figure 2 and Figure 4The feeding device further comprises a diverter valve 9, which comprises a valve main pipe 91, a connecting pipe 92, a valve branch pipe 93 and a piston rod 94, wherein:

[0094] The valve main pipe 91 is connected in series to the raw material delivery pipeline 100;

[0095] One end of the connecting pipe 92 is connected to the side wall of the valve main pipe 91, and the piston rod 94 is slidably inserted into the connecting pipe 92 from the other end of the connecting pipe 92;

[0096] One end of the valve branch pipe 93 is connected to the side wall of the connecting pipe 92, and the other end of the valve branch pipe 93 is connected to the feed pipeline 31 or the discharge pipeline 41;

[0097] The valve main pipe 91, the connecting pipe 92 and the valve branch pipe 93 are connected in sequence.

[0098] Specifically, the axis of the connecting pipe 92 is perpendicular to the axis of the valve main pipe 91, and the angle between the axis of the connecting pipe 92 and the axis of the valve branch pipe 93 is an acute angle (or an obtuse angle); the valve opening can be changed by moving the piston rod 94 along the axis of the connecting pipe 92, thereby changing the slurry flow rate flowing into or out of the diverter valve 9. In this embodiment, there are two diverter valves 9, one of which is connected between the raw material conveying pipeline 100 and the feed pipeline 31 (that is, the other end of the valve branch pipe 93 is connected to the feed pipeline 31), and the other diverter valve 9 is connected between the raw material conveying pipeline 100 and the discharge pipeline 41 (that is, the other end of the valve branch pipe 93 is connected to the discharge pipeline 41).

[0099] Compared with directly using a three-way interface or a three-way valve, the diverter valve 9 provided in the present application can reduce the impact on the raw material slurry transportation line. During the transportation process, the raw material slurry is divided into two paths at one of the diverter valves 9, one path continues to be transported along the valve main pipe 91, and the other path flows obliquely to the batching kettle 2 through the connecting pipe 92 and the valve branch pipe 93. The raw material slurry containing Class B products that has been evenly mixed in the batching kettle 2 enters the raw material transportation pipeline 100 through the oblique inlet at another diverter valve 9. Since the slurry flows obliquely into or out of the diverter valve 9, the impact on the slurry in the valve main pipe 91 can be reduced, thereby minimizing the impact on the alcohol-acid ratio in the original production process system.

[0100] In some embodiments, the diverter valve 9 also includes a knob 95, which is connected to the connecting pipe 92 through fasteners such as pull rods and nuts, and the knob 95 is threadedly connected to the piston column 94. By turning the knob 95, the piston column 94 can be controlled to move along the axis of the connecting pipe 92, thereby controlling the valve opening.

[0101] In other embodiments, the diverter valve 9 further includes a piston column driving member, which may be a motor or a cylinder, a housing of which is connected to the valve main pipe 91 or the connecting pipe 92, and a power output end of the piston column driving member is connected to the piston column 94. The piston column driving member drives the piston column 94 to move, so as to realize automatic adjustment of the valve opening of the diverter valve 9.

[0102] The second aspect of the present invention provides a B-grade PET regeneration system, which includes a raw material preparation tank, a preparation device, a raw material delivery pipeline 100 and a feeding device in any of the above embodiments, wherein:

[0103] Raw material preparation tanks are used to store raw materials for producing PET products;

[0104] The preparation device is used to process the raw materials into PET products;

[0105] The raw material conveying pipeline 100 is connected between the raw material preparation tank and the preparation device.

[0106] Specifically, the preparation device includes an esterification kettle, and the raw material conveying pipeline 100 is specifically connected between the raw material preparation tank and the esterification kettle. During the production process, the raw material slurry can be used as a conveying medium to convey the Class B PET product in the feeding device, and the Class B PET product is mixed in the raw material slurry and fed into the esterification kettle, thereby realizing the recycling of Class B PET products and achieving the purpose of reducing costs and increasing efficiency. In addition, using the raw material as a conveying medium to convey the Class B PET product can achieve the purpose of intermittently adding Class B PET products on the original continuous PET production line, so that the production line can adapt to the production change in time and improve the stability and safety of the production line.

[0107] The third aspect of the present invention provides a process for applying to the above-mentioned B-level PET regeneration system, and the process comprises the following steps:

[0108] Feed part of the raw materials in the raw material delivery pipeline 100 into the batching kettle 2 through the feed pipeline 31;

[0109] Feed the Class B product in silo 1 into batching kettle 2;

[0110] The mixed raw materials and Class B products in the batching kettle 2 are sent into the raw material conveying pipeline 100 through the discharge pipeline 41 .

[0111] The above-mentioned B-grade PET regeneration process is described in detail below with reference to a specific embodiment.

[0112] Reference Figure 2During the transportation of the mixed slurry containing the B-grade PET product, the valves on the purge pipeline 61, the flushing pipeline 71 and the emptying branch 45 are all in a closed state, and the discharge valve 43 on the discharge pipeline 41 is in an open state.

[0113] First, the B-grade PET product is manually delivered to the silo 1, and the star-shaped discharger 10 controls the B-grade PET product to enter the batching kettle 2 at a flow rate of 650 kg / h; at the same time, a raw material slurry (specifically a mixture of terephthalic acid and ethylene glycol) is introduced into the batching kettle 2 through the upstream diverter valve 9, and the opening of the flow regulating valve 33 can be controlled to control the raw material slurry to enter the batching kettle 2 at a flow rate of 5850 kg / h.

[0114] Next, the B-class PET product and the raw material slurry in the batching kettle 2 are stirred and mixed uniformly at 100°C, 100rpm and normal pressure to obtain a mixed slurry with a content of 20wt% of the B-class PET product. The mixed slurry enters the discharge pipeline 41 through the bottom sampling valve 42 of the kettle, is pressurized by the centrifugal pump 44 and is transported to the downstream diverter valve 9, and then enters the raw material transport pipeline 100 through the side inlet of the diverter valve 9, and then passes through the esterification, pre-polycondensation, final polycondensation, solid phase polycondensation and other stages in sequence with the raw material slurry, and is finally converted into a Class A PET product.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A feeding device, characterized in that: The invention comprises a material bin (1), a batching kettle (2), a raw material feeding mechanism (3) and a mixing and discharging mechanism (4), wherein: The silo (1) is used to store the Class B product produced during the production process of the product, and the discharge port of the silo (1) is connected to the first feed port (21) of the batching kettle (2) through a pipeline; The raw material feeding mechanism (3) comprises a feeding pipeline (31), and the feeding pipeline (31) is connected between the raw material conveying pipeline (100) on the product production line and the second feeding port (22) of the batching kettle (2); The mixing and discharging mechanism (4) comprises a discharging pipeline (41), wherein the discharging pipeline (41) is connected between the mixing outlet (23) of the batching kettle (2) and the raw material conveying pipeline (100), and the connection position between the discharging pipeline (41) and the raw material conveying pipeline (100) is located downstream of the connection position between the feeding pipeline (31) and the raw material conveying pipeline (100).

2. The feeding device according to claim 1, characterized in that: The raw material feeding mechanism (3) further comprises a spray module (32) arranged on the feeding pipeline (31).

3. The feeding device according to claim 2, characterized in that: It also includes an exhaust gas recovery mechanism (5), the exhaust gas recovery mechanism (5) including an exhaust gas pipeline (51) and an exhaust gas sealing tank (52), the exhaust gas pipeline (51) being connected between the exhaust gas sealing tank (52) and the exhaust gas outlet of the spray module (32).

4. The feeding device according to claim 1, characterized in that: The mixing and discharging mechanism (4) further comprises a kettle bottom sampling valve (42) and / or a discharging valve (43) and / or a centrifugal pump (44) arranged on the discharging pipeline (41); And / or, the discharge pipeline (41) is provided with an emptying branch (45), and the emptying branch (45) is provided with an emptying valve (46).

5. The feeding device according to claim 1, characterized in that: The invention also comprises a purge mechanism (6), wherein the purge mechanism (6) comprises a purge pipeline (61), a purge gas storage tank (62), and a purge valve (63), wherein the purge pipeline (61) is connected between the purge gas storage tank (62) and the batching kettle (2), and the purge valve (63) is arranged on the purge pipeline (61); And / or, it also includes a flushing mechanism (7), the flushing mechanism (7) includes a flushing pipeline (71), a flushing liquid storage tank (72) and a purge valve (73), wherein the flushing pipeline (71) is connected between the flushing liquid storage tank (72) and the discharge pipeline (41), and the purge valve (73) is arranged on the flushing pipeline (71).

6. The feeding device according to claim 1, characterized in that: The device further comprises a purge mechanism (6), wherein the purge mechanism (6) comprises a purge pipeline (61) and a distributor (64), wherein: The inlet of the purge pipeline (61) is used to input the purge gas, and the outlet of the purge pipeline (61) is connected to the inlet of the distributor (64); The distributor (64) is arranged in the batching kettle (2) and is located at the bottom of the batching kettle (2). The distributor (64) is provided with a plurality of outlets distributed at intervals.

7. The feeding device according to claim 1, characterized in that: It also includes a liquid level meter (8) arranged on the side wall of the batching kettle (2); The raw material feeding mechanism (3) further comprises a flow regulating valve (33) arranged on the feeding pipeline (31), and the flow regulating valve (33) is interlocked with the liquid level meter (8) for control.

8. The feeding device according to any one of claims 1 to 7, characterized in that: It also includes a diverter valve (9), which includes a valve main pipe (91), a connecting pipe (92), a valve branch pipe (93) and a piston rod (94), wherein: The valve main pipe (91) is connected in series to the raw material conveying pipeline (100); One end of the connecting pipe (92) is connected to the side wall of the valve main pipe (91), and the piston rod (94) is slidably inserted into the connecting pipe (92) from the other end of the connecting pipe (92); One end of the valve branch pipe (93) is connected to the side wall of the connecting pipe (92), and the other end of the valve branch pipe (93) is connected to the feed pipeline (31) or the discharge pipeline (41); The valve main pipe (91), the connecting pipe (92) and the valve branch pipe (93) are connected in sequence.

9. A B-grade PET regeneration system, characterized in that: It comprises a raw material preparation tank, a preparation device, a raw material conveying pipeline (100) and a feeding device according to any one of claims 1 to 8, wherein: The raw material preparation tank is used to store the raw materials for producing PET products; The preparation device is used to process the raw material into a PET product; The raw material conveying pipeline (100) is connected between the raw material preparation tank and the preparation device.

10. A B-grade PET regeneration process, characterized in that: The B-level PET regeneration system as claimed in claim 9 comprises the following steps: Feeding part of the raw materials in the raw material conveying pipeline (100) into the batching kettle (2) through the feed pipeline (31); Feeding the Class B product in the silo (1) into the batching kettle (2); The raw materials and the Class B product mixed in the batching kettle (2) are sent into the raw material conveying pipeline (100) through the discharge pipeline (41).

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