CN111530361A

CN111530361A - Production system of PBS biodegradable material

Info

Publication number: CN111530361A
Application number: CN202010483094.8A
Authority: CN
Inventors: 王有超; 陶家宏
Original assignee: Oerlikon Barmag Huitong Yangzhou Engineering Co Ltd
Current assignee: Oerlikon Barmag Huitong Yangzhou Engineering Co Ltd
Priority date: 2020-06-01
Filing date: 2020-06-01
Publication date: 2020-08-14
Also published as: WO2021244193A1

Abstract

The invention relates to a production system of PBS biodegradable materials, which comprises an A/B esterification kettle and a second esterification kettle, wherein a slurry inlet at the top of the A/B esterification kettle is connected with outlets of a first slurry preparation tank and a second slurry preparation tank; the slurry blending tank II is connected with the BDO feeding pipe and is provided with a dibasic acid feeding port; the outlet of the A/B esterification kettle is respectively connected with the inlet of the second esterification kettle, the outlet of the second esterification kettle is connected with the inlet of the first polycondensation kettle through an esterification material pump, the outlet of the first polycondensation kettle is connected with the inlet of the second polycondensation kettle through a first polycondensation material pump, the outlet of the second polycondensation kettle is connected with the inlet of the final polycondensation reaction kettle through a second polycondensation material pump, and the outlet of the final polycondensation reaction kettle is connected with the inlet of the tackifying reaction kettle through a melt conveying pump. The system can greatly reduce the consumption of raw materials and side reactions.

Description

Production system of PBS biodegradable material

Technical Field

The invention relates to a production system of polyester chips, in particular to a production system of PBS (Poly Butylene succinate) biodegradable materials, and belongs to the technical field of polyester chip production equipment.

Background

With the progress of society and the improvement of the requirement on environmental protection, the production of the biodegradable materials of the PBS class is more and more widely applied, and the PBS class comprises PBS (poly butylene succinate), PBAT (poly butylene adipate terephthalate), PBST (poly butylene succinate-co-butylene terephthalate), PBSA (poly butylene succinate-co-butylene adipate), and the like.

1, 4-Butanediol (BDO), terephthalic acid (PTA), dibasic acid and the like are required to be used for producing PBS, the dibasic acid comprises adipic acid, sebacic acid or succinic acid and the like, in the prior art, the terephthalic acid, the dibasic acid and the 1, 4-butanediol are pulped according to a certain proportion and then sent to an esterification reaction kettle for reaction, the mixture is sent to a second esterification kettle for further reaction after the reaction, and then granules are cut after the first polycondensation, the second polycondensation, the final polycondensation and the tackifying, and the traditional PBS production system has the following defects:

1. terephthalic Acid (PTA) and dibasic acid such as adipic acid and 1,4 Butanediol (BDO) react in the same esterification reaction kettle, in order to ensure the reaction of PTA and BDO, the esterification temperature is up to 230-250 ℃, so that the side reaction of 1,4 butanediol is serious, the consumption of raw materials is high, the generation amount of Tetrahydrofuran (THF) is large, the pressure of a tetrahydrofuran treatment device is increased, and the product quality is poor.

And 2, dehydrating the PBS slices by a centrifugal separator or a vacuum drum machine, wherein only the water on the surfaces of the PBS slices can be removed, so that the water content of the PBS slices entering the intermediate bin is still high. If the packaging is directly adopted, the degradation is easy to cause, a certain amount of tetrahydrofuran contained in the slices is easy to release gradually after a period of time, the produced materials have batch difference and cannot reach uniformity, and the use grade of the product is influenced.

3. And the mixture of BDO, water and a little oligomer at the gas phase outlets of the first polycondensation kettle, the second polycondensation kettle, the final polycondensation reaction kettle and the tackifying reaction kettle enters a scraper condenser, is sprayed and captured by the scraper condenser, most of gas is changed into liquid under the cooling of spraying liquid, and a little non-condensable gas is pumped away by a subsequent vacuum unit. A little oligomer falls to the bottom of the blade under the action of gravity and blade scraping. And finally, the oligomer particles and BDO fall into the hot well together through an atmosphere leg, so that the hot well is blocked or a scraper is damaged in the scraper wall hanging process, a scraper condenser is stopped, and the oligomer in the hot well needs to be periodically discharged into a slag discharging box for cleaning.

4. In the actual production process, the atmospheric leg can also be blocked, so that the spraying cannot normally run, the vacuum fluctuation or the vacuum loss is caused, the shutdown treatment is carried out when the vacuum fluctuation or the vacuum loss is serious, the treatment time is long frequently, and the production loss is huge. The traditional slag discharging box is mostly in a vertical flat shape and is difficult to open and clean, or is in a square shape, the sealing surface is too large, and the sealing is difficult; the filter screen is easy to block, so that the filtrate is directly overflowed to the liquid outlet with slag discharge, and the liquid outlet is blocked; the slag intercepted on the top layer of the filter screen is excessive, and the slag is quickly stacked to cause the blockage of the feed inlet of the slag discharging box.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provide a production system of PBS biodegradable materials, which can produce PBS, PBAT, PBST, PBSA and the like, can greatly reduce the consumption of BDO and the generation of side reactions and tetrahydrofuran.

In order to solve the technical problems, the production system of the PBS biodegradable material comprises an esterification reaction kettle, wherein the esterification reaction kettle comprises an A esterification kettle, a B esterification kettle and a second esterification kettle, a slurry inlet at the top of the A esterification kettle is connected with a discharge hole of a first slurry preparation tank, a top inlet of the first slurry preparation tank is connected with a discharge hole of a first slurry preparation tank, and the top of the first slurry preparation tank is connected with a BDO feed pipe and is provided with a PTA feed port; a slurry inlet at the top of the esterification kettle B is connected with a discharge hole of a slurry preparation tank II, a top inlet of the slurry preparation tank II is connected with a discharge hole of a slurry preparation tank II, and the top of the slurry preparation tank II is connected with a BDO feed pipe and is provided with a dibasic acid feed port; the discharge ports of the esterification kettle A and the esterification kettle B are respectively connected with the feed port of the second esterification kettle, the discharge port of the second esterification kettle is connected with the feed port of the first polycondensation kettle through an esterification material pump, the discharge port of the first polycondensation kettle is connected with the feed port of the second polycondensation kettle through a first polycondensation material pump B2, the discharge port of the second polycondensation kettle is connected with the feed port of the final polycondensation reaction kettle through a second polycondensation material pump, and the discharge port of the final polycondensation reaction kettle is connected with the feed port of the tackifying reaction kettle through a melt conveying pump.

Compared with the prior art, the invention has the following beneficial effects: the BDO and the PTA are prepared in a slurry preparation tank I in batches according to a certain molar ratio, are fully and uniformly stirred and then are sent into a slurry preparation tank I, and then enter an esterification kettle A from the slurry preparation tank I to carry out esterification reaction; and (3) blending BDO and adipic acid, sebacic acid, succinic acid or other dibasic acids in batches according to a certain molar ratio in a slurry blending tank II, fully and uniformly stirring, sending into a slurry blending tank II, and then sending into an esterification kettle B from the slurry blending tank II to perform esterification reaction. Because the reaction temperature of dibasic acid such as adipic acid and BDO is 170-210 ℃, the reaction temperature of PTA and BDO is 230-250 ℃, the esterification reaction is separately carried out according to the difference of the temperature and the pressure required by the reaction, the consumption of BDO can be greatly reduced, the generation of tetrahydrofuran is reduced, and the quality of materials can be accurately controlled. And respectively feeding the esterified ester B and the esterified ester A into a second esterification kettle for mixed esterification, feeding the mixed esterified material into a first polycondensation kettle for pre-polycondensation, feeding the pre-polycondensation material into a second polycondensation kettle for re-polycondensation, feeding the re-polycondensation material into a final polycondensation reaction kettle for final polycondensation, and feeding the final polycondensation material into a tackifying reaction kettle for tackifying. The esterification kettle A and the esterification kettle B react under different process conditions, so that the side reaction of BDO can be reduced, the consumption of raw materials and the yield of tetrahydrofuran are reduced, and the product quality is improved.

As an improvement of the invention, a discharge port of the tackifying reaction kettle is connected with a granulator I through a melt booster pump I; and the outlet of the melt conveying pump is connected with the feed inlet of the melt heat exchanger through a melt metering pump, the discharge outlet of the melt heat exchanger and the outlet of the chain extender adding system are connected with the inlet of the melt booster pump II together, and the discharge outlet of the melt booster pump II is connected with the granulator II. And the melt after being tackified by the tackification reaction kettle in the first route is sent to a granulator for granulating by a melt booster pump, so that the requirements of most customers, including the requirements of food-grade products, can be met. In the second route, after the final polycondensation material is sent out by a melt conveying pump, the final polycondensation material is firstly metered by a melt metering pump, then the temperature is regulated by a melt heat exchanger, then the final polycondensation material and the modified material from the chain extender adding system enter a second melt booster pump together, and the final polycondensation material and the modified material are sent into a second granulator by the second melt booster pump for granulation, so that the online modification of certain products can be realized, the melt route is short, the retention time is short, the thermal decomposition is not easy, and the product quality is good; meanwhile, the system has good compatibility, can produce products with different characteristics, and meets different downstream customers.

As a further improvement of the invention, outlets of the first granulator and the second granulator are respectively connected with respective slicing intermediate bins, discharge valves of the intermediate bins are respectively arranged at the bottoms of the slicing intermediate bins, outlets of the discharge valves of the intermediate bins are respectively connected with slicing feed inlets at the tops of the first slicing and drying towers through first air conveying pipelines, slicing discharge outlets at the bottoms of the first slicing and drying towers are respectively connected with inlets of discharge valves of the drying towers, outlets of the discharge valves of the drying towers are respectively connected with slicing feed inlets at the tops of the second slicing and drying towers through second air conveying pipelines, slicing discharge outlets at the bottoms of the second slicing and drying towers are respectively connected with main feed inlets of a mixing bin, and outlets of the mixing bins are respectively connected with a vacuum packaging machine. PBS type section in the section intermediate bin is discharged through intermediate bin bleeder valve, get into section drying tower one under the transport of wind-powered pipeline one, the section carries out the heat and moisture exchange with hot-blast in section drying tower one, moisture is evaporated with tetrahydrofuran, the section of preliminary drying is discharged from the drying tower bleeder valve, get into section drying tower two under the transport of wind-powered pipeline two, the section continues to carry out the heat and moisture exchange with hot-blast in section drying tower two, remaining moisture is evaporated with tetrahydrofuran back, get into the mixing bunker from main feed inlet and keep in, then get into vacuum packaging machine packing. Because two-stage series evaporation removes moisture and tetrahydrofuran in PBS type slices, and adopts vacuum packaging, the degradation can not occur after the PBS type slices are placed for a period of time, the quality of the product is improved by one grade, and the use requirement of food grade can be met.

As a further improvement of the invention, tower body hot air outlets at the tops of the first slicing drying tower and the second slicing drying tower are connected with an air inlet of a dust remover through dust removal air suction pipes, an air outlet at the top of the dust remover is connected with an air supply port of an air supply pipeline III through an air return pipeline, a feed inlet of the air supply pipeline III is connected with an outlet of a slicing and batching valve, an inlet of the slicing and batching valve is connected with an outlet of a slicing and batching hopper, and an outlet of the air supply pipeline III is connected with an auxiliary feed inlet of the mixing bin. And the hot air after moisture absorption is discharged from tower body hot air outlets at the tops of the first slicing drying tower and the second slicing drying tower respectively and enters a dust remover through a dust removal air suction pipe, dust in the slices is intercepted by the dust remover, and clean tail gas enters an air supplementing opening of an air supply pipeline III through an air return pipeline for recycling. The slice viscosity of different molecular weight is different, the auxiliary material exists temporarily in the slice batching fill, discharge from the slice batching valve, get into mixing bunker from the supplementary feed inlet under the transport of wind-driven pipeline three, with the slice homogeneous mixing in proportion that gets into just dry from main feed inlet, change the proportion of mixing, mixed slice can obtain the fuse-element of different viscosity when extruding, the application scope of product is wider, waste heat and nitrogen gas in the clean tail gas have been retrieved simultaneously, greatly reduced the consumption of heat energy and material.

As a further improvement of the invention, the main feed port is positioned in the center of the top of the mixing bin, the auxiliary feed ports are symmetrically positioned on two sides of the main feed port, at least three mixing chutes are arranged in the inner cavity of the mixing bin, each mixing chute extends vertically and is symmetrically distributed by taking the axis of the mixing bin as the center, the lower end of each mixing chute bends towards the conical hopper at the bottom of the mixing bin, a plurality of chute sections are uniformly arranged along the height direction of each mixing chute, each chute section is respectively provided with one chute port, and each chute port is spirally distributed along the circumference of the mixing chute. The main feed port and the auxiliary feed port simultaneously feed materials and simultaneously fall above the material layer, so that static material mixing on each section of the mixing bin is realized, the slices in the central area of the mixing bin sequentially flow out from the bottom outlet of the mixing bin, and first-in first-out is realized; partial section of mixing bunker peripheral region gets into the inner chamber of compounding elephant trunk from each swift current material mouth, down fast and fall into mixing bunker's awl fill along the compounding elephant trunk, realize partial sliced back FIFO, realize the developments compounding in mixing bunker's direction of height, FIFO's static compounding and back FIFO's developments compounding combined action, the section drying tower is fought with the section batching and is arranged the section and realize the homogeneous mixing in mixing bunker, mixed sliced degree of consistency and quality have been improved greatly. Each mixing elephant trunk is central symmetry and distributes, and the swift current material mouth on the mixing elephant trunk is evenly distributed in direction of height and circumferencial direction, can further improve the homogeneity that the section was mixed.

As a further improvement of the invention, the first slice drying tower and the second slice drying tower respectively comprise a vertical cylindrical tower body, the center of the top of the tower body is provided with the slice feeding hole, and the hot air outlet of the tower body is positioned at one side of the slice feeding hole; the hot air inlet of the tower body is arranged at the lower part of the tower body, the drying tower cone hopper is connected to the bottom of the tower body, the slice discharge port is located at the lower end of the drying tower cone hopper, a plurality of distribution umbrella caps in a right circular cone shape are arranged along the axis of the tower body, besides the distribution umbrella caps at the top layer, baffle plates coaxial with the distribution umbrella caps are respectively arranged above the distribution umbrella caps and below the distribution umbrella caps at the bottom layer, and each baffle plate is in a horn mouth shape with a large upper part and a small lower part. PBS slices enter the inner cavity of the tower body from a slice feeding hole at the top, firstly fall on the outer conical surface of the distributing umbrella cap at the top layer, are uniformly scattered all around after being splashed, then fall on the inner conical surface of the baffle plate downwards, are splashed towards the center, fall from the central hole of the baffle plate and fall on the outer conical surface of the distributing umbrella cap at the next layer; hot nitrogen or air enters from the lower part of the tower and heats the PBS-based chips while flowing upward in a counter-current manner. Therefore, in the process of repeated turning-back downward flight of the PBS slices, moisture or THF is gradually removed, the slices fall into the conical hopper of the drying tower and are discharged from the slice discharge hole at the bottom of the conical hopper, and hot air is discharged from the tower body hot air outlet at the top of the tower.

As a further improvement of the invention, the upper end of each baffle plate is respectively connected to the inner wall of the tower body, each baffle plate is of a thin-wall cavity structure, the lower wall of each baffle plate is respectively connected with a corresponding baffle plate air supply ring pipe through a plurality of uniformly distributed radial communicating pipes, each baffle plate air supply ring pipe surrounds the periphery of the tower body and is respectively provided with a baffle plate hot air interface, and a plurality of baffle plate hot air holes are uniformly distributed on the upper wall of each baffle plate; the nitrogen pipe is connected with the air inlet of the gas heater, the air outlet of the gas heater is connected with the hot air main pipe, the hot air main pipe is respectively connected with the hot air branch pipes of each layer, the hot air branch pipes of each layer and the cold air branch pipes of the same layer are connected with the air supply pipe of the baffle plate of the layer, and the outlet of the air supply pipe of the baffle plate of each layer is respectively connected with the hot air interface of the baffle plate of the layer. Hot nitrogen or hot air enters the inner cavity of each baffle plate from the air supply ring pipe of the baffle plate along each radial communicating pipe, and is sprayed upwards from the hot air holes of each baffle plate on the upper wall of the baffle plate, and when the slices fall on the baffle plate, the slices are dried and stirred by hot air sprayed from the hot air holes of the baffle plate, so that the drying effect and uniformity are further improved. The nitrogen enters a hot air main pipe after being heated by a gas heater, the temperature is measured by a hot air temperature sensor, and the opening degree of a heat supply regulating valve is increased if the temperature of hot air is lower; if the temperature of the hot air is higher than the set temperature, the opening degree of the heat supply regulating valve is reduced. Then hot air enters the hot air branch pipes of each layer, is mixed with cold air from the cold air branch pipes of the same layer, enters the air supply pipe of the baffle plate of the layer, and then enters the baffle plate of the layer through the air supply ring pipe of the baffle plate. When the temperature detected by the air supply temperature sensor of a certain layer of baffle plate is lower, the cold air regulating valve of the layer is closed; otherwise, the cold air regulating valve of the layer is opened. Thus, different temperatures are controlled in stages through a multilayer and independent temperature control system according to the control process requirement of the drying tower, so as to achieve the purpose of efficiently removing moisture and tetrahydrofuran.

As a further improvement of the invention, the diameter of the upper end of the drying tower cone hopper is larger than that of the tower body, the lower end of the tower body is inserted into the upper port of the drying tower cone hopper, the upper port of the drying tower cone hopper is provided with an annular sealing cover, and the inner edge of the annular sealing cover is welded on the outer wall of the tower body; the annular cavity below the annular sealing cover is connected with a tower body air supply ring pipe through a plurality of radial communicating pipes which are uniformly distributed, the circumference of the tower body air supply ring pipe is provided with the tower body hot air inlet, and an annular hot air channel with a downward opening is arranged between the lower port of the tower body and the inner wall of the drying tower cone hopper. Hot air enters an annular cavity at the upper end of a conical hopper of the drying tower from an air supply annular pipe of the tower body along each radial communicating pipe, is blown downwards from an annular hot air channel between the tower body and the conical hopper of the drying tower, flows downwards along a circumferential wall in the conical hopper of the drying tower and then upwards along a central area, heats slices falling into the conical hopper of the drying tower, loosens the slices, and prevents the slices from being stuck to each other to cause blockage and the like.

As a further improvement of the invention, the gas phase outlets of the first polycondensation kettle, the second polycondensation kettle, the final polycondensation reaction kettle or the tackifying reaction kettle are respectively connected with the side wall inlets of the respective vacuum traps, the top gas phase port of each vacuum trap is respectively connected with the gas inlet of the scraper condenser, the bottom outlet of each vacuum trap is respectively connected with the top inlet of the vacuum collection tank through an electric cut-off valve, the top gas inlet of each vacuum collection tank is also connected with a nitrogen pipe through a nitrogen valve of the collection tank, and the bottom of each vacuum collection tank is respectively provided with a discharge valve of the collection tank; the medium outlet of each scraper condenser is respectively connected with the respective hot well through an atmospheric leg, the liquid phase outlet of each hot well is connected with the inlet of a spraying circulating pump, and the outlet of the spraying circulating pump is connected with the spraying port of the scraper condenser through a circulating liquid cooler. After being discharged from gas phase ports of the polycondensation kettles or the tackifying kettles, the mixture of BDO, water and oligomers firstly enters a vacuum catcher, because of the reduction of the gas velocity, the liquid oligomers are remained at the bottom of the vacuum catcher under the action of gravity, the BDO, the water and a small amount of oligomers enter a scraper condenser to be sprayed and collected, the condensed oligomers are discharged from a medium outlet of the scraper condenser along with the BDO and enter a hot well through an atmospheric leg to be filtered, the spraying liquid BDO is pumped out by a spraying circulating pump, and the BDO returns to a spraying port of the scraper condenser to be sprayed circularly after being cooled by a circulating liquid cooler. After accumulating to certain level gauge in the vacuum trap, open electronic trip valve, nitrogen gas in the vacuum collection tank gets into the vacuum trap and discharges from its gaseous phase mouth, and liquid oligomer gets into the storage in the vacuum collection tank, stores to a certain amount after, opens the collection tank nitrogen gas valve of vacuum collection tank, fills nitrogen gas into the vacuum collection tank, opens the collection tank discharge valve of vacuum collection tank bottom simultaneously, discharges liquid oligomer to the collecting vat in, after the emission, continues to let in nitrogen gas about 10 seconds, carries out nitrogen seal to the vacuum collection tank, then closes collection tank nitrogen gas valve. Because most of the oligomer is collected by the vacuum catcher, the flow of the spraying liquid required by the scraper condenser is greatly reduced, the energy consumption is reduced, and the stability of a vacuum system is greatly improved; in addition, the amount of residue discharged into the hot well from the scraper condenser is greatly reduced, the running stability of the scraper is improved, and the service life of the scraper is greatly prolonged.

As a further improvement of the invention, the top of the hot well is provided with a hot well top cover, a longitudinal clapboard is arranged along the longitudinal axis of the hot well to divide the inner cavity of the hot well into a left half and a right half, a left inner chamber and a right inner chamber are symmetrically arranged at two sides of the middle section of the longitudinal clapboard, the outer side of the transverse wallboard of the left inner chamber is a left outer chamber, the outer side of the transverse wallboard of the right inner chamber is a right outer chamber, the bottoms of the left inner chamber and the right inner chamber are respectively provided with a conical hopper, the lowest part of the two conical hoppers is respectively connected with a hot well slag discharging port, and the two hot well slag discharging ports respectively extend downwards to; the bottoms of the left outer chamber and the right outer chamber are respectively provided with the hot well liquid phase outlets; the hot well top cover is spliced with two atmospheric legs, the lower ends of the two atmospheric legs are respectively inserted into the lower parts of the inner cavities of the left inner chamber and the right inner chamber, the upper part of each transverse wallboard is respectively provided with an overflow port communicated with the corresponding outer chamber, the inner port of each overflow port is respectively covered with a filter plate, the left side and the right side of each filter plate are respectively spliced in the vertical slots on the inner end surfaces of the transverse wallboards, the outer port of each overflow port is respectively covered with an outward-protruding arc-shaped filter basket, and the left side and the right side of each arc-shaped filter basket are respectively spliced in the vertical slots on the outer end surfaces of the transverse wallboards. BDO and a little oligomer flow into the lower part of the left inner chamber through the valve and the pipeline at the bottom of the scraper condenser and the atmosphere leg at the left side, and simultaneously play a role of liquid seal, BDO or other spray liquid flows out after being filtered for the first time by the filter plate, enters the inner cavity of the arc-shaped filter basket, enters the left outer chamber after being filtered for the second time by the arc-shaped filter basket, flows out from the hot well liquid phase outlet at the bottom of the left outer chamber, is pumped out by the spray circulating pump, and is sent to the scraper condenser for circulating spray after being cooled. Impurities such as oligomer and the like are blocked in the left inner chamber, fall into the conical hopper, are discharged from a hot well slag discharge port and enter the cleaning box. If the left atmospheric leg is blocked, the atmospheric leg on the right side can be immediately switched to work, the hot well liquid phase outlet and the hot well slag discharge port are also switched to work on the right side, so that the spraying system can stably operate for a long time, the normal operation of the polymerization device is ensured, the parking treatment caused by the blockage of the atmospheric leg, the loss is greatly reduced, and the normal operation of production is ensured. The filter plate is used for filtering for the first time and trapping impurities with larger sizes, and the filter plate is close to the top of the hot well, so that the filter plate is convenient to draw out and clean and is also convenient to install and return. The convex arc filter basket not only increases the filter area, but also increases the space for containing the objects; the filter plate and the edges of the left side and the right side of the arc-shaped filter basket are embedded in the vertical slots, so that the filter plate and the arc-shaped filter basket are convenient to pull, insert, clean and assemble.

As a further improvement of the invention, the hot well slag discharge port is respectively connected with a cleaning box feed inlet at the top of a cleaning box, the cleaning box comprises a horizontal barrel with one closed end, the front end port of the cleaning box is hinged with a cleaning box sealing cover which can be opened and closed, the periphery of the barrel of the cleaning box is coated with a cleaning box jacket, the inner cavity of the cleaning box is provided with a plurality of square filtering drawers which are sequentially superposed from top to bottom, the frames at the left side and the right side of each square filtering drawer are respectively supported in guiding chutes by rollers, each guiding chute extends along the axial direction of the cleaning box and is respectively fixed at the two sides of the inner wall of the cleaning box, the bottom of the inner cavity of the cleaning box is provided with an arc bottom drawer, the bottom of the arc bottom drawer is supported at the bottom of the inner wall of the cleaning box by rollers, the bottoms of the arc bottom drawer and each square filtering drawer are respectively provided with filtering nets, and the mesh number of the lower filtering net is sequentially larger than, the lower end of the feed inlet of the cleaning box points to the central area of the square filter drawer at the top layer, and the bottom center of the cleaning box is provided with a liquid discharge port of the cleaning box. The frames of the drawers are erected upwards, so that the mixture can be prevented from overflowing from the periphery of the filter screen, the guide sliding grooves are convenient for the square filter drawers to be drawn out, cleaned and put back, and the square filter drawers can be ensured to be in a horizontal state; the drawer at the bottom of the arc is positioned at the bottom of the arc of the cleaning box and is in a stable and balanced state, so that the guide sliding groove can be omitted, and the drawer is directly supported at the bottom of the arc of the cleaning box through the idler wheels. The mixture of oligomer and BDO enters the inner cavity of the cleaning box from the feeding hole of the cleaning box, firstly falls on the square filter drawer at the top layer, and is subjected to rough filtration, the mesh of the filter screen at the top layer is large, the liquid permeability is very strong, the overflow caused by blockage is avoided, the largest discharged slag is intercepted, and the slightly smaller discharged slag falls into the next layer for continuous filtration; so successive layer improves filtration precision, and the slag discharging that is the finest is held back by arc bottom drawer, filters the back step by step through the multilayer, and clear BDO is discharged from the cleaning box leakage fluid dram of cleaning box bottom. The square filtering drawer or the drawer with the arc-shaped bottom can be pulled out for cleaning by opening the cleaning box sealing cover, and the cleaning frequency can be higher than that of other square filtering drawers because the eyelet of the drawer with the arc-shaped bottom is smallest and is most easily blocked, so that each layer is not required to be pulled out for cleaning every time, the cleaning workload is reduced, and the pollution to the field working environment is reduced; the drawer with the arc-shaped bottom is deepest, and the height of the object to be stored is high, so that the overflow is not easy to cause. Steam can be introduced into the jacket of the cleaning box to improve the temperature of the inner cavity of the cleaning box and avoid blockage caused by medium solidification.

Drawings

The invention will be described in further detail with reference to the following drawings and detailed description, which are provided for reference and illustration purposes only and are not intended to limit the invention.

FIG. 1 is a flow chart of a production system for PBS biodegradable materials according to the present invention.

FIG. 2 is a flow chart of the chip drying system of the present invention.

Fig. 3 is a front view of the slice drying tower one or the slice drying tower two in fig. 2.

Fig. 4 is a top view of fig. 3.

FIG. 5 is a top view of one of the baffle embodiments of FIG. 3.

Figure 6 is a cross-sectional view of the mixing silo of figure 3.

FIG. 7 is a detailed flow diagram of the oligomer capture system of the present invention.

Fig. 8 is a front view of a heat well of the present invention.

Figure 9 is a top view of figure 8 with the atmospheric leg removed.

Fig. 10 is a cross-sectional view taken along a-a in fig. 9.

Fig. 11 is a partially enlarged view of fig. 8.

FIG. 12 is a front view of the purge bin of FIG. 7.

Fig. 13 is a left side view of fig. 12.

In the figure: 1a, a first slurry blending tank; 1a1.PTA feed port; 1b, a second slurry blending tank; 1b1. a dibasic acid feeding port; 2a, a first slurry preparation tank; 2b, a second slurry preparation tank; 3a.A esterification kettle; 3b.B esterification kettle; 4. a second esterification kettle; 5. a first polycondensation kettle; 6. a second polycondensation kettle; 7. a final polycondensation reaction kettle; 8. a tackifying reaction kettle; 9. a chain extender addition system; 10a, a first granulator; 10b, a second granulator; 11. a slicing intermediate bin; 11a, an intermediate bin discharge valve; 12-1, a first slice drying tower; 12-2, a second slice drying tower; 12a, a slice feed inlet; 12b, a tower body hot air outlet; 12c, a pressure measuring port; 12d, a tower body temperature measurement interface; 12e. a sight glass; 12f, a standby port; 12g, reserving a valve port; 12h, a manhole; 12j. a level gauge interface; 12k, separating umbrella caps; 12m. baffle plate; 12m1. baffle hot air hole; 12n, a drying tower cone hopper; 12n1. stirring shaft; 12n2. stirring disk; 12p, discharging cone; 12p1. slice discharge port; 12p2. hand holes; 12q, baffle plate air supply ring pipes; 12r, a tower body air supply ring pipe; 12r1, a baffle hot air interface; 12s, a discharge cone air supply ring pipe; 13. a discharge valve of the drying tower; 14. a drying tower underpants tee; 15. slicing and batching hoppers; a slice batching valve; 16. a mixing bin; 16a, a main feed inlet; 16b, auxiliary feed inlets; 16c, a mixing chute; 16c1, a material sliding port; 16d, a mixing bin vent tee joint; 17-1, vacuum packaging machine I; 17-2, vacuum packaging machine II; 18. a dust remover; 19. a gas heater; 20. a vacuum trap; catcher level gauge 20 a; 20b, an electric cut-off valve; 21. a vacuum collection tank; 21a, a nitrogen valve of the collecting tank; a collection tank drain valve; 22. a scraper condenser; 23. a hot well; 23a, a hot well slag discharge port; 23b, hot well liquid phase outlet; a hot well level gauge port; 23d. thermal well temperature wellhead; 23e. hot well head cover; 23e1. hot well manhole covers; longitudinal partitions; 23g, transverse wall panels; 23h1. left inner chamber; 23h2. right inner chamber; 23j1. left outer compartment; 23j2. right outer chamber; 23k, a sealing seat; 23k1. a filler; 23k2. packing gland; 23m. filter plate; 23m1. filter pad handles; 23n. arc-shaped filter baskets; 23n1. basket handle; a conical hopper; 23q. an atmospheric leg; 24. cleaning the box; 24a, cleaning box feed inlet; 24b, cleaning a box exhaust port; 24c, cleaning a tank liquid outlet; 24d, cleaning the box sealing cover; cleaning a box jacket; 24e1. cleaning box jacket lower interface; 24e2. jacket upper port; 24f, a square filter drawer; 24g. an arc-shaped bottom drawer; 24h, rolling wheels; 24j. a guide chute; searchlighting lamp sockets; 24m. glass sight glass viewing port; 24n. a multi-pipe interface; 25. a process tower; 26. a top reflux drum; 27. cold trap; 28. a vacuum pump; 29a, a first jet pump; 29b, a second jet pump; g0.BDO feed pipe; G1. a first air supply pipeline; G2. a second air supply pipeline; G3. a third air supply pipeline; G4. a dust removal aspiration channel; G5. a return air duct; G6. a nitrogen gas pipe; G7. a hot air main pipe; G8. a cold air branch pipe; G9. a steam pipe; G10. a condensate pipe; g11a. heat medium supply pipe; g11b, a heating medium oil return pipe; v1, a heat supply regulating valve; v2, a cold air regulating valve; t1, a hot air temperature sensor; t2, a baffle plate air supply temperature sensor; B1. an esterification material pump; B2. a first polycondensation material pump; B3. a second polycondensation material pump; B4. a melt transfer pump; B5. a first melt booster pump; B6. a melt metering pump; B7. a second melt booster pump; B8. a spray circulation pump; F1. a first filter; F2. a second filter; F3. a third filter; F4. a fourth filter; F5. a fifth filter; F6. a sixth filter; H1. a melt heat exchanger; H2. a circulating liquid cooler.

Detailed Description

In the following description of the present invention, the terms "front", "rear", "left", "right", "inside", "outside", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not mean that the apparatus must have a specific orientation.

As shown in fig. 1, the production system of PBS biodegradable materials of the present invention includes an esterification reaction kettle, a first polycondensation kettle 5, a second polycondensation kettle 6, a final polycondensation kettle 7, and a tackifying reaction kettle 8, where the esterification reaction kettle includes an a esterification kettle 3a, a B esterification kettle 3B, and a second esterification kettle 4. The top of the first slurry blending tank 1a is connected with a BDO feed pipe G0 and is provided with a PTA feed port 1a1, the discharge port of the first slurry blending tank 1a is connected with the top inlet of the first slurry preparation tank 2a, and the discharge port of the first slurry preparation tank 2a is connected with the slurry inlet at the top of the esterification kettle A3 a through a screw conveying pump. The top of the second slurry blending tank 1B is connected with a BDO feed pipe G0 and is provided with a dibasic acid feed port 1B1, the discharge port of the second slurry blending tank 1B is connected with the top inlet of the second slurry preparation tank 2B, and the discharge port of the second slurry preparation tank 2B is connected with the slurry inlet at the top of the esterification kettle B3B through a screw conveying pump. The gas phase ports of the esterification kettles A3 a and B3B are respectively connected with respective process towers 25, the process towers 25 are respectively matched with tower top reflux tanks 26, and the gas phase ports of the tower top reflux tanks 26 are respectively connected with a vacuum pump 28 through cold traps 27.

The discharge ports of the esterification kettles 3a and 3B are respectively connected with the feed port of the second esterification kettle 4, the discharge port of the second esterification kettle 4 is connected with the feed port of the first polycondensation kettle 5 through an esterification material pump B1 and a filter F1, the discharge port of the first polycondensation kettle 5 is connected with the feed port of the second polycondensation kettle 6 through a first polycondensation material pump and a filter second F2, the discharge port of the second polycondensation kettle 6 is connected with the feed port of the final polycondensation reaction kettle 7 through a second polycondensation material pump B3 and a filter third F3, and the discharge port of the final polycondensation reaction kettle 7 is connected with the feed port of the tackifying reaction kettle 8 through a melt conveying pump B4 and a filter fourth F4.

The BDO and the PTA are prepared in a slurry preparation tank I1 a in batches according to a certain molar ratio, are fully and uniformly stirred and then are sent into a slurry preparation tank I2 a, and then are sent into an esterification kettle A3 a from the slurry preparation tank I2 a through a screw conveying pump to carry out esterification reaction; BDO and adipic acid, sebacic acid, succinic acid or other dibasic acids are mixed in a slurry mixing tank II 1B in batches according to a certain molar ratio, are fully and uniformly stirred and then are sent into a slurry mixing tank II 2B, and then are sent into an esterification kettle B3B from the slurry mixing tank II 2B through a screw conveying pump for esterification reaction. Because the reaction temperature of dibasic acid such as adipic acid and BDO is 170-210 ℃, the reaction temperature of PTA and BDO is 230-250 ℃, the esterification reaction is separately carried out according to the difference of the temperature and the pressure required by the reaction, the consumption of BDO can be greatly reduced, the generation of tetrahydrofuran is reduced, and the quality of materials can be accurately controlled. The esterified ester B and the esterified ester A are respectively sent into a second esterification kettle 4 for mixed esterification, the mixed esterified material enters a first polycondensation kettle 5 for pre-polycondensation, the pre-polycondensation material enters a second polycondensation kettle 6 for re-polycondensation, the re-polycondensation material enters a final polycondensation reaction kettle 7 for final polycondensation, and the final polycondensation material enters a tackifying reaction kettle 8 for tackifying.

A first pelletizing route: the discharge port of the tackifying reaction kettle 8 is connected with the first granulator 10a through a first melt booster pump B5 and a fifth filter F5, and the melt tackified by the tackifying reaction kettle 8 is sent into the first granulator 10a through a first melt booster pump B5 to be granulated, so that the requirements of most customers, including the requirements of food-grade products, can be met.

A second pelletizing line: an outlet of the melt conveying pump B4 is connected with a feeding hole of a melt heat exchanger H1 through a melt metering pump B6, a discharging hole of the melt heat exchanger H1 and an outlet of the chain extender adding system 9 are connected with an inlet of a melt booster pump II B7 together, and a discharging hole of a melt booster pump II B7 is connected with a granulator II 10B through a filter six F6. After the final polycondensation material is sent out by a melt conveying pump B4, the final polycondensation material is firstly metered by a melt metering pump B6, then the temperature is regulated by a melt heat exchanger H1, then the final polycondensation material and the modified material from the chain extender adding system 9 enter a melt booster pump II B7 together, and the final polycondensation material is sent into a granulator II 10B for granulation by the melt booster pump II B7, so that the online modification of certain products can be realized, the melt line is short, the retention time is short, the thermal decomposition is not easy, and the product quality is good; meanwhile, the system has good compatibility, can produce products with different characteristics, and meets different downstream customers.

The gas phase ports of the first polycondensation kettle 5, the second polycondensation kettle 6, the final polycondensation reaction kettle 7 and the tackifying reaction kettle 8 are respectively connected with respective oligomer capturing systems, each oligomer capturing system respectively comprises a scraper condenser, and the gas phase port of the scraper condenser of the first polycondensation kettle 5 is connected with a vacuum pump 28 through a cold trap 27. The gas phase port of the scraper condenser of the second polycondensation kettle 6 and the gas phase port of the scraper condenser of the final polycondensation reaction kettle 7 are connected to a first jet pump 29a, the gas phase port of the scraper condenser of the tackifying reaction kettle 8 is connected to a second jet pump 29b, and exhaust ports of the first jet pump 29a and the second jet pump 29b are connected with corresponding vacuum pumps 28 through respective cold traps 27.

As shown in fig. 1 and 2, outlets of the first granulator 10a and the second granulator 10b are respectively connected to respective slicing intermediate bins 11, a discharging valve 11a of the intermediate bins is arranged at the bottom of the slicing intermediate bin 11, an outlet of the discharging valve 11a of the intermediate bins is connected to a slicing inlet 12a at the top of a first slicing and drying tower 12-1 through a first pneumatic conveying pipeline G1, a slicing outlet 12p1 at the bottom of the first slicing and drying tower 12-1 is connected to an inlet of a discharging valve 13 of a drying tower, an outlet of the discharging valve 13 of the drying tower is connected to a slicing inlet 12a at the top of a second slicing and drying tower 12-2 through a second pneumatic conveying pipeline G2, a slicing outlet 12p1 at the bottom of the second slicing and drying tower 12-2 is connected to a main inlet 16a of a mixing bin 16, and an outlet of the mixing bin 16 is connected to a.

PBS slices in the slice intermediate bin 11 are discharged through an intermediate bin discharge valve 11a, enter a slice drying tower I12-1 under the conveying of an air conveying pipeline I G1, carry out heat and moisture exchange with hot air in the slice drying tower I12-1, moisture and tetrahydrofuran are evaporated, primarily dried slices are discharged from a drying tower discharge valve 13, enter a slice drying tower II 12-2 under the conveying of an air conveying pipeline II G2, continue to carry out heat and moisture exchange with the hot air in the slice drying tower II 12-2, and enter a mixing bin 16 from a main feed inlet 16a for temporary storage after the remaining moisture and the tetrahydrofuran are evaporated, and then enter a vacuum packaging machine for packaging. Because two-stage series evaporation removes moisture and tetrahydrofuran in PBS type slices, and adopts vacuum packaging, the degradation can not occur after the PBS type slices are placed for a period of time, the quality of the product is improved by one grade, and the use requirement of food grade can be met.

The hot air outlet 12b of the tower body at the tops of the first slicing drying tower 12-1 and the second slicing drying tower 12-2 is connected with an air inlet of a dust remover 18 through a dust removal suction pipe G4, an air outlet at the top of the dust remover 18 is connected with an air supply port of an air supply pipeline III G3 through an air return pipeline G5, a feed inlet of the air supply pipeline III G3 is connected with an outlet of a slicing and batching valve 15a, an inlet of the slicing and batching valve 15a is connected with an outlet of a slicing and batching hopper 15, and an outlet of the air supply pipeline III G3 is connected with an auxiliary feed inlet 16b of a mixing bin 16. The hot air after moisture absorption is discharged from a tower body hot air outlet 12b at the top of the first slice drying tower 12-1 and the second slice drying tower 12-2 respectively, enters the dust remover 18 through a dust removal suction pipe G4, dust in the slices is intercepted by the dust remover 18, and clean tail gas enters an air supply pipe III G3 through an air return pipe G5 for recycling. The slice viscosity of different molecular weight is different, the batching exists temporarily in slice batching fill 15, discharge from slice batching valve 15a, get into mixing bunker 16 from supplementary feed inlet 16b under the transport of air-assisted pipeline three G3, with the slice homogeneous mixing in proportion that gets into just dry from main feed inlet 16a, change the proportion of mixing, the mixed slice can obtain the fuse-element of different viscosity when extruding, the application scope of product is wider, waste heat and nitrogen gas in the clean tail gas have been retrieved simultaneously, greatly reduced the consumption of heat energy and material.

As shown in fig. 6, the main feed port 16a is located at the top center of the mixing bunker 16, the auxiliary feed ports 16b are symmetrically located at both sides of the main feed port 16a, at least three mixing chutes 16c are provided in the inner cavity of the mixing bunker 16, each mixing chute 16c extends vertically and is symmetrically distributed with the axis of the mixing bunker as the center, the lower end of each mixing chute 16c is bent toward the conical hopper at the bottom of the mixing bunker 16, a plurality of chute sections are uniformly provided along the height direction of each mixing chute 16c, each chute section is provided with one chute port 16c1, and each chute port 16c1 is spirally distributed along the circumference of the mixing chute 16c.

The main feed port 16a and the auxiliary feed port 16b feed materials simultaneously and fall above the material layer simultaneously, static material mixing on each section of the mixing bin 16 is realized, slices in the central area of the mixing bin sequentially flow out from the bottom outlet of the mixing bin 16, and first-in first-out is realized; partial slices in the peripheral area of the mixing bin enter an inner cavity of the mixing chute 16c from each chute opening 16c1, rapidly descend along the mixing chute 16c and fall into a conical hopper of the mixing bin 16, the last-in first-out of partial slices is realized, dynamic mixing is realized in the height direction of the mixing bin 16, the static mixing of the first-in first-out and the dynamic mixing of the last-in first-out act together, uniform mixing of slices discharged from the slice drying tower and the slice proportioning hopper 15 in the mixing bin 16 is realized, and the uniformity and the quality of the mixed slices are greatly improved. The mixing slide pipes 16c are distributed in central symmetry, and the material sliding openings 16c1 on the mixing slide pipes 16c are uniformly distributed in the height direction and the circumferential direction, so that the uniformity of slice mixing can be further improved.

A slice discharge port 12p1 at the bottom of the second slice drying tower 12-2 is provided with a drying tower vent tee 14, two outlets of the drying tower vent tee 14 are respectively connected with main feed ports 16a of the two mixing bins 16, and an outlet of an air supply pipeline III G3 is respectively connected with auxiliary feed ports 16b of the two mixing bins 16; the outlets at the bottoms of the two mixing bins 16 are respectively provided with a mixing bin vent tee 16d, and the outlets of the mixing bin vent tee 16d are respectively connected with the feed inlets of the first vacuum packaging machine 17-1 and the second vacuum packaging machine 17-2. The second slicing and drying tower 12-2 can randomly select the mixing bin 16 through the drying tower vent tee 14, the two mixing bins 16 can adopt different mixing proportions, the bottoms of the two mixing bins 16 can be selectively butted with the first vacuum packaging machine 17-1 or the second vacuum packaging machine 17-2 through the mixing bin vent tee 16d, the first vacuum packaging machine 17-1 can be a ton packaging machine, and the second vacuum packaging machine 17-2 can be a 25kg packaging machine, so that the viscosity requirements and the large and small packaging requirements of different customers can be met.

The first slice drying tower 12-1 and the second slice drying tower 12-2 respectively comprise a vertical cylindrical tower body, a slice feeding hole 12a is formed in the center of the top of the tower body, and a hot air outlet 12b of the tower body is located on one side of the slice feeding hole 12 a; the lower part of the tower body is provided with a tower body hot air inlet, the bottom of the tower body is connected with a drying tower cone hopper 12n, a slice discharge port 12p1 is positioned at the lower end of the drying tower cone hopper 12n, a plurality of right-circular cone-shaped distribution umbrella caps 12k are arranged along the axis of the tower body, besides the top distribution umbrella cap 12k, baffle plates 12m coaxial with the distribution umbrella caps 12k are respectively arranged above the distribution umbrella caps 12k and below the bottom distribution umbrella cap 12k, and each baffle plate 12m is in a horn mouth shape with a large top and a small bottom.

As shown in fig. 3, PBS slices enter the inner cavity of the tower body from the slice inlet 12a at the top, first fall on the outer conical surface of the distributing umbrella cap 12k at the top, are uniformly scattered all around after being splashed, then fall downwards on the inner conical surface of the baffle plate 12m, are splashed towards the center, fall from the central hole of the baffle plate 12m and fall on the outer conical surface of the distributing umbrella cap 12k at the next layer; hot nitrogen or air enters from the lower part of the tower and heats the PBS-based chips while flowing upward in a counter-current manner. In this way, in the process of repeated turning-back and downward flight of the PBS slices, moisture or THF is gradually removed, finally the slices fall into the conical hopper 12n of the drying tower and are discharged from the slice discharge port 12p1 at the bottom of the conical hopper, and hot air is discharged from the tower hot air outlet 12b at the top of the tower.

The upper end of each baffle plate 12m is respectively connected to the inner wall of the tower body, each baffle plate 12m is of a thin-wall cavity structure, the lower wall of each baffle plate 12m is respectively connected with a corresponding baffle plate air supply ring pipe 12q through a plurality of radial communicating pipes which are uniformly distributed, each baffle plate air supply ring pipe 12q surrounds the periphery of the tower body and is respectively provided with a baffle plate hot air connector 12r1, and a plurality of baffle plate hot air holes 12m1 are uniformly distributed on the upper wall of each baffle plate 12m. Hot nitrogen or hot air enters the inner cavity of each baffle plate 12m from the baffle plate air supply circular pipe 12q along each radial communicating pipe, is sprayed out upwards from each baffle plate hot air hole 12m1 on the upper wall of the baffle plate 12m, and when falling on the baffle plate 12m, slices are dried and stirred by hot air sprayed out from the baffle plate hot air holes 12m1, so that the drying effect and uniformity are further improved.

As shown in fig. 2, a nitrogen pipe G6 is connected with an air inlet of the gas heater 19, an air outlet of the gas heater 19 is connected with a hot air main pipe G7, a hot air main pipe G7 is respectively connected with hot air branch pipes of each layer, the hot air branch pipes of each layer and cold air branch pipes G8 of the same layer are connected with a baffle plate air supply pipe of the layer, and outlets of the baffle plate air supply pipes of each layer are respectively connected with a baffle plate hot air interface 12r1 of the layer; a hot air temperature sensor T1 is installed on the hot air header pipe G7, a hot side inlet of the gas heater 19 is connected with a steam pipe G9 through a heat supply adjusting valve V1, a hot side outlet of the gas heater 19 is connected with a condensate pipe G10, and the opening degree of the heat supply adjusting valve V1 is controlled by the temperature measured by the hot air temperature sensor T1; baffle air supply temperature sensors T2 are respectively arranged on the baffle air supply pipes of each layer, cold air adjusting valves V2 are respectively arranged on the cold air branch pipes G8 of each layer, and the opening degree of each cold air adjusting valve V2 is respectively controlled by the temperature measured by the baffle air supply temperature sensor T2 of the same layer.

The nitrogen enters a hot air manifold G7 after being heated by a gas heater 19, the temperature is measured by a hot air temperature sensor T1, and if the temperature of the hot air is lower, the opening degree of a heat supply regulating valve V1 is increased; if the temperature of the hot air is higher, the opening degree of the heat supply regulating valve V1 is reduced. Then hot air enters the hot air branch pipe of each layer, is mixed with cold air from the cold air branch pipe G8 at the same layer, enters the baffle plate air supply pipe of the layer, and then enters the baffle plate 12m of the layer through the baffle plate air supply circular pipe 12q. When the temperature detected by the air supply temperature sensor T2 of a certain layer of baffle plate is lower, the cold air regulating valve V2 of the layer is closed; otherwise, the cold air regulating valve V2 of the layer is opened. Thus, different temperatures are controlled in stages through a multilayer and independent temperature control system according to the control process requirement of the drying tower, so as to achieve the purpose of efficiently removing moisture and tetrahydrofuran.

As shown in fig. 3, the diameter of the upper end of the drying tower cone 12n is larger than that of the tower body, the lower end of the tower body is inserted into the upper port of the drying tower cone 12n, the upper port of the drying tower cone 12n is provided with an annular sealing cover, and the inner edge of the annular sealing cover is welded on the outer wall of the tower body; an annular cavity below the annular sealing cover is connected with a tower body air supply ring pipe 12r through a plurality of radial communicating pipes which are uniformly distributed, a tower body hot air inlet is arranged on the circumference of the tower body air supply ring pipe 12r, and an annular hot air channel with a downward opening is arranged between the lower port of the tower body and the inner wall of the drying tower cone hopper 12n. Four or six radial communicating pipes are uniformly distributed on the same circumference so as to ensure that hot air is uniformly distributed on the circumference of the tower body and slices on the same section are uniformly heated. Hot air enters an annular cavity at the upper end of a conical hopper 12n of the drying tower from an air supply ring pipe 12r of the tower body along each radial communicating pipe, and is blown downwards from an annular hot air channel between the tower body and the conical hopper 12n of the drying tower, the hot air flows downwards along a circumferential wall in the conical hopper 12n of the drying tower and then upwards along a central area, slices falling into the conical hopper 12n of the drying tower are heated and loosened, and the blocking caused by wall adhesion and mutual adhesion is prevented.

The lower part of the drying tower cone hopper 12n is provided with a stirring rotor, the stirring rotor comprises a stirring shaft 12n1 and a plurality of stirring disks 12n2 fixed on the stirring shaft 12n1, two ends of the stirring shaft 12n1 are respectively supported on the drying tower cone hopper 12n through bearing seats and sealed with the drying tower cone hopper wall, and the diameter of the stirring disks 12n2 is gradually reduced from the middle section of the stirring shaft 12n1 to the two ends. The stirring shaft drives each stirring disc piece 12n2 to rotate, and the slices falling into the conical hopper 12n of the drying tower are stirred to keep the slices in a loose state, so that blockage caused by adhesion is prevented. The diameter of the stirring disk 12n2 is distributed in a step shape, which can better match the shape of the drying tower cone 12n to stir the slices more thoroughly.

The lower extreme nestification of drying tower awl fill 12n has a play awl 12p, the last port of play awl 12p seals and nestification is in the periphery of drying tower awl fill 12n lower extreme, the annular cavity of drying tower awl fill 12n lower extreme periphery links to each other with play awl air feed ring canal 12s through many evenly distributed's radial communicating pipe, be equipped with out the hot air interface of play awl on the circumference of play awl air feed ring canal 12s, be equipped with the annular hot air passageway that the opening is decurrent between the lower port of drying tower awl fill 12n and the inner wall of play awl 12p, section discharge gate 12p1 is located the lower extreme of play awl 12p. Hot-blast follow play awl air feed ring pipe 12s along each radial communicating pipe get into the annular cavity at drying tower awl fill 12n and play awl 12p connection position, blow off downwards from the annular hot air passageway between drying tower awl fill 12n and the play awl 12p downwards, it is earlier downward along the circumference wall in play awl 12p, again along the regional stirring rotor who goes up of central point, on the one hand further heats to the section that falls into play awl 12p, on the other hand makes the section roll loose, prevent to glue the wall, mutual adhesion causes the jam etc..

The circumferential wall of the discharge cone 12p is provided with a hand hole 12p2 communicated with the inner cavity, and the circumferences of the upper part and the middle part of the tower body are respectively provided with a manhole. If the slice discharge port 12p1 is blocked, the hand hole 12p2 can be opened, so that the materials can be conveniently moved out from the hand hole 12p2, the equipment is recovered to be smooth, the pipeline is prevented from being disassembled, or the materials enter from a manhole above the equipment, and the sectional cleaning or the overhaul is carried out, so that the parking processing time is reduced.

As shown in fig. 4, the top end cap of the tower body is further provided with a pressure measuring port 12c, a tower body temperature measuring port 12d, a viewing mirror 12e, a standby port 12f and a reserved valve port 12g, and the circumferences of the upper part and the middle part of the tower body are respectively provided with a manhole 12h. Can carry out the pressure measurement to the tower body inner chamber through pressure measurement mouth 12c, can observe the sliced mobile state in the tower body through sight glass 12e, can enter into the tower body from manhole 12h, clear up or overhaul the tower body inner chamber in segments.

The tower body is provided with a plurality of tower body temperature measuring interfaces along the height direction, and a drying tower temperature transmitter is respectively arranged in each tower body temperature measuring interface; the tower body is provided with a plurality of level indicator interfaces 12j along the height direction, and level alarms are respectively arranged in the level indicator interfaces 12j. The temperature transmitter of the drying tower can measure the temperature of different cylinder sections in the tower body in real time, so as to control the temperature of air supplied to different baffle plates 12m. The level alarm is set stage by stage, and when abnormality occurs, different treatment schemes can be adopted according to the level condition.

As shown in fig. 5, each baffle plate 12m may be formed by splicing a plurality of sector plates distributed in an annular array, the splicing seams of two adjacent layers of baffle plates 12m are staggered, and the closer to the bottom of the tower body, the smaller the included angle between the baffle plate 12m and the axis of the tower body is. The included angle between each layer of baffle plate 12m and the vertical wall of the tower body can be adjusted to control the descending speed of the slices, and the retention time of the slices at each section of the tower body can be controlled through the angle adjustment of the baffle plates 12m to adapt to the slices with different properties and particle sizes, so that the moisture and tetrahydrofuran in the slices can be removed more efficiently. The slices just entering the drying tower are relatively flat due to the high water content, so that the contact time of the slices with hot air is prolonged, and the evaporation capacity is increased; the slices reaching the lower part of the tower body are basically dry, the evaporation capacity is small, the baffle plates 12m are arranged relatively steeply to improve the descending speed of the slices, the phenomenon that the descending speed of the slices at the upper part is slow and the descending speed of the slices at the lower part is fast appears in the tower body, and the possibility of blockage in the tower body is greatly reduced. The splicing seams of the two adjacent layers of baffle plates 12m are staggered, a small number of slices falling from the splicing seams can fall on the next layer of baffle plate 12m, and the short circuit of the blanking with longer height of the slices is avoided.

As shown in fig. 7, the gas phase outlet of each polycondensation kettle or tackifying kettle is connected with the side wall inlet of a vacuum catcher 20 through a jacket pipe, the top gas phase port of the vacuum catcher 20 is connected with the gas inlet of a scraper condenser 22 through a jacket pipe, the bottom outlet of the vacuum catcher 20 is connected with the top inlet of a vacuum collection tank 21 through an electric cut-off valve 20b, the top gas inlet of the vacuum collection tank 21 is further connected with a nitrogen pipe G6 through a collection tank nitrogen valve 21a, and the bottom of the vacuum collection tank 21 is provided with a collection tank discharge valve 21 b; the medium outlet of the scraper condenser 22 is connected with the hot well 23 through the atmospheric leg 23q, the hot well liquid phase outlet 23B is connected with the inlet of the spray circulating pump B8, the outlet of the spray circulating pump B8 is connected with the inlet of the circulating liquid cooler H2, and the outlet of the circulating liquid cooler H2 is connected with the spray port of the scraper condenser 22.

After being discharged from gas phase ports of the polycondensation kettles or the tackifying kettles, the mixture of BDO, water and oligomers firstly enters a vacuum catcher 20, liquid oligomers are remained at the bottom of the vacuum catcher 20 under the action of gravity due to the reduction of gas velocity, the BDO, the water and a small amount of oligomers enter a scraper condenser 22 to be sprayed and collected, the condensed oligomers are discharged from a medium outlet of the scraper condenser 22 along with the BDO, enter a hot well through an atmosphere leg 23q to be filtered, spraying liquid BDO is pumped out by a spraying circulating pump B8, and is cooled by a circulating liquid cooler H2 and then returns to a spraying port of the scraper condenser 22 to be sprayed circularly.

After a certain liquid level meter is accumulated in the vacuum catcher 20, the electric cut-off valve 20b is opened, nitrogen in the vacuum collection tank 21 enters the vacuum catcher 20 and is discharged from a gas phase port of the vacuum catcher, liquid oligomer enters the vacuum collection tank 21 for storage, after a certain amount of storage, the collection tank nitrogen valve 21a of the vacuum collection tank 21 is opened, the nitrogen is filled into the vacuum collection tank 21, the collection tank discharge valve 21b at the bottom of the vacuum collection tank 21 is opened, the liquid oligomer is discharged into the collection tank, after the discharge is finished, the nitrogen continues to be filled for about 10 seconds, the vacuum collection tank 21 is subjected to nitrogen sealing, and then the collection tank nitrogen valve 21a is closed.

Since most of the oligomer is collected by the vacuum trap 20, the spray liquid flow consumed by the flight condenser 22 will be greatly reduced, reducing energy consumption, while the stability of the vacuum system will be greatly improved; in addition, the amount of residue discharged from the scraper condenser 22 into the hot well will be greatly reduced, the stability of scraper operation will be improved, and the service life of the scraper will be greatly extended.

The outer walls of the vacuum catcher 20 and the vacuum collection tank 21 are respectively coiled with a half-pipe heater, the lower end inlets of the two half-pipe heaters are respectively connected with a heating medium oil supply pipe G11a, and the upper end outlets of the two half-pipe heaters are respectively connected with a heating medium oil return pipe G11b. By heating the heating medium, the vacuum catcher 20 and the vacuum collecting tank 21 can be kept above the melting point of each medium, so that the various media can be kept in fluidity, and solidification blockage is avoided.

A catcher liquid level meter 20a is installed in the middle section of the side wall of the vacuum catcher 20, the opening and closing of the electric cut-off valve 20b is controlled by the catcher liquid level meter 20a, and a pressure sensor is installed on the vacuum collection tank 21. When the liquid level in the vacuum trap 20 reaches the level at which the trap level gauge 20a is located, the electric shut-off valve 20b opens the drain. The pressure in the vacuum collection tank 21 can be observed by the pressure sensor, and the completion of the nitrogen seal and the formation of the negative pressure can be judged.

As shown in fig. 8 to 10, a hot well top cover 23e is arranged at the top of the hot well 23, a longitudinal partition plate 23f is arranged along the longitudinal axis of the hot well 23 to divide the inner cavity of the hot well into left and right halves, a left inner chamber 23h1 and a right inner chamber 23h2 are symmetrically arranged at both sides of the middle section of the longitudinal partition plate 23f, transverse wall plates 23g are respectively arranged at the front and rear of the left inner chamber 23h1 and the right inner chamber 23h2, the outer space of the left inner chamber 23h1 is a left outer chamber 23j1, the outer space of the right inner chamber 23h2 is a right outer chamber 23j2, tapered hoppers 23p are respectively arranged at the bottoms of the left inner chamber 23h1 and the right inner chamber 23h2, the lowest parts of the two tapered hoppers 23p are respectively connected with hot well slag discharge ports 23a, and the two hot well slag discharge ports 23; the bottoms of the left outer chamber 23j1 and the right outer chamber 23j2 are respectively provided with the hot well liquid phase outlet 23 b; two atmospheric legs 23q are inserted on the hot well top cover 23e, the lower ends of the two atmospheric legs 23q are respectively inserted into the lower parts of the inner cavities of the left inner chamber 23h1 and the right inner chamber 23h2, the upper parts of the transverse wall plates 23g are respectively provided with an overflow port communicated with the corresponding outer chamber, the inner ports of the overflow ports are respectively covered with filter plates 23m, the left side and the right side of each filter plate 23m are respectively inserted into vertical slots on the inner end surfaces of the transverse wall plates 23g, the outer ports of the overflow ports are respectively covered with outward convex arc-shaped filter baskets 23n, and the left side and the right side of each arc-shaped filter basket 23n are respectively inserted into vertical slots on the outer end surfaces of the transverse wall plates 23.

BDO and a little oligomer flow into the lower part of the left inner chamber 23h1 through a valve and a pipeline at the bottom of the scraper condenser through the left atmospheric leg 23q, and simultaneously play a role of liquid seal, the BDO flows out after being filtered for the first time by a filter plate 23m upwards, enters the inner chamber of an arc filter basket 23n, enters a left outer chamber 23j1 after being filtered for the second time by the arc filter basket 23n, flows out from a hot well liquid phase outlet 23B at the bottom of the left outer chamber 23j1, is pumped out by a spray circulating pump B8, is cooled, and then is sent to the scraper condenser for circulating spray. Impurities such as oligomers are retained in the left interior chamber 23h1, fall into the conical hopper 23p, exit the hot well slag discharge port 23a and enter the purge bin 24. If the left atmospheric leg 23q is blocked, the operation can be immediately switched to the right atmospheric leg 23q, and the hot well liquid phase outlet 23b and the hot well slag discharge port 23a are also switched to the right side to operate, so that the spraying system can stably operate for a long time, the normal operation of the polymerization device is ensured, the shutdown treatment caused by the blockage of the atmospheric leg 23q is avoided, the loss is greatly reduced, and the normal operation of production is ensured.

The filter plate 23m is used for filtering for the first time and trapping larger-sized impurities, and the filter plate 23m is close to the top of the vacuum sealing tank, so that the filter plate 23m is convenient to draw out and clean and is also convenient to put back. The convex arc-shaped filter basket 23n not only increases the filtering area, but also increases the containing space; the filter plate 23m and the edges of the left side and the right side of the arc-shaped filter basket 23n are embedded in the vertical slots, so that the filter plate and the arc-shaped filter basket are convenient to pull, insert, clean and assemble.

Each arc-shaped filter basket 23n extends towards the lower part of the corresponding outer chamber, and the arc surface and the bottom of each arc-shaped filter basket 23n are respectively provided with a filter screen. The filtering area of the arc-shaped filtering basket 23n is further increased, so that the arc-shaped filtering basket 23n is cleaned once after the system continuously works for several days, and the cleaning workload is reduced.

As shown in fig. 11, two atmosphere legs 23q are respectively located at two sides of the longitudinal partition 23f and respectively penetrate through the central holes of the sealing seats 23k, the two sealing seats 23k are respectively welded on the hot well top cover 23e, packing 23k1 is respectively arranged in a packing box between the outer wall of the atmosphere leg 23q and the inner wall of the sealing seat, packing glands 23k2 are respectively arranged at the upper parts of the packing 23k1, and flanges of the packing glands 23k2 are connected with flanges of the sealing seats 23k through gland screws. The gland screw is tightened, the packing 23k1 is tightly pressed in the stuffing box through the packing gland 23k2, the periphery of the atmospheric leg 23q is sealed, the atmospheric leg 23q can be guaranteed to vertically and freely slide, and the expansion caused by the temperature change of the system can be automatically adapted.

Two hot well manhole covers 23e1 are symmetrically arranged on the position, far away from the longitudinal partition plate 23f, on the transverse axis of the hot well top cover 23e, and each pair of filter plates 23m and the arc-shaped filter baskets 23n are respectively positioned below the hole openings of the hot well manhole covers 23e1. The hot well manhole cover 23e1 is opened, the filter plate 23m and the arc filter basket 23n can be pulled out for cleaning, the filter plate 23m and the arc filter basket 23n are inserted back after cleaning, and then the hot well manhole cover 23e1 is reset, so that the hot well top cover 23e is prevented from being integrally detached, and the workload during cleaning is reduced.

Handles are respectively arranged on the top of each filter plate 23m and the arc-shaped filter basket 23n. The filter plate 23m can be easily inserted and pulled by the filter plate handle 23m1, and the arc-shaped filter basket 23n can be easily inserted and pulled by the filter basket handle 23n1.

The left inner chamber 23h1, the right inner chamber 23h2, the left outer chamber 23j1 and the right outer chamber 23j2 are respectively provided with a hot well material level meter port 23c, the material levels of the inner chamber and the outer chamber can be displayed and monitored on the DCS in real time, and when the atmosphere leg 23q is blocked, the DCS sends alarm information in real time, so that DCS personnel can rapidly arrange field personnel for treatment.

The bottom of the two sides of the hot well 23 are respectively provided with a hot well temperature gauge port 23d, so that the temperature of BDO can be displayed on DCS in real time.

As shown in fig. 12 and 13, the cleaning box 24 includes a horizontal cylinder with a closed end, a cleaning box cover 24d is hinged to the front end of the cleaning box 24, the cleaning box cover 24e is wrapped around the cylinder of the cleaning box 24, a plurality of square filter drawers 24f are sequentially stacked in the inner cavity of the cleaning box 24 from top to bottom, the frames on the left and right sides of each square filter drawer 24f are respectively supported in the guide chutes 24j through the rollers 24h, the guide chutes 24j extend along the axial direction of the cleaning box 24 and are respectively fixed on the two sides of the inner wall of the cleaning box 24, the bottom of the inner cavity of the cleaning box 24 is provided with an arc bottom drawer 24g, the bottom of the arc bottom drawer 24g is supported on the bottom of the inner wall of the cleaning box 24 through the rollers 24h, the bottoms of the arc bottom drawer 24g and the square filter drawer 24f are respectively provided with filter screens, and the mesh number of the lower filter screen is sequentially larger than that of the upper filter screen, the top of the cleaning box 24 is provided with a cleaning box feeding hole 24a and a cleaning box exhaust hole 24b, the upper end of the cleaning box feeding hole 24a is connected with the hot well slag discharge hole 23a, the lower end of the cleaning box feeding hole 24a points to the central area of the top square filtering drawer 24f, and the center of the bottom of the cleaning box 24 is provided with a cleaning box liquid discharge hole 24c.

The frames of the drawers are erected upwards, so that the mixture can be prevented from overflowing from the periphery of the filter screen, the guide sliding grooves 24j are convenient for the square filter drawers 24f to be drawn out, cleaned and put back, and the square filter drawers 24f can be ensured to be in a horizontal state; the drawer 24g with the arc bottom is positioned at the arc bottom of the cleaning box 24 and is in a stable and balanced state, the guide sliding groove 24j can be omitted, and the drawer is directly supported at the arc bottom of the cleaning box 24 through the roller 24h. The mixture of oligomer and BDO enters the inner cavity of the cleaning box 24 from the feeding hole 24a of the cleaning box, firstly falls on the square filtering drawer 24f at the top layer, and is subjected to rough filtering, the mesh of the filter screen at the top layer is large, the liquid permeability is very strong, the overflow caused by blockage is avoided, the maximum slag is intercepted, and the slightly smaller slag falls into the next layer for continuous filtering; thus, the filtering precision is improved layer by layer, the finest slag is intercepted by the drawer 24g at the arc bottom, and after multi-layer step-by-step filtering, the clean BDO is discharged from the liquid outlet 24c of the cleaning box at the bottom of the cleaning box 24. The square filtering drawer 24f or the arc-shaped bottom drawer 24g can be pulled out for cleaning by opening the cleaning box sealing cover 24d, and because the eyelet of the arc-shaped bottom drawer 24g is the smallest and is easy to block, the cleaning frequency can be higher than that of other square filtering drawers 24f, each layer does not need to be pulled out for cleaning every time, the cleaning workload is reduced, and the pollution to the field working environment is reduced; the drawer 24g with the arc-shaped bottom is deepest, and the height of the contained objects is high, so that overflow is not easy to cause.

A searchlight mouth 24k and a glass sight glass observation mouth 24m are respectively arranged at the left side and the right side of the exhaust port 24b of the cleaning box, light is injected from the searchlight mouth 24k, and the inner interception state can be observed from the glass sight glass observation mouth 24m at the other side, so that the cleaning time can be accurately determined.

The bottom of the cleaning box jacket 24e is connected with a cleaning box jacket lower connector 24e1, the top of the cleaning box jacket 24e is connected with a jacket upper connector 24e2, steam can be introduced into the cleaning box jacket 24e, the steam enters from the jacket upper connector 24e2 at the top, and condensed water is discharged from the cleaning box jacket lower connector 24e1 at the bottom, so that the temperature of the inner cavity of the cleaning box 24 is increased, and blockage caused by medium solidification is avoided.

The top of the cleaning box 24 is also provided with a multi-pipeline interface 24n, and the multi-pipeline interface 24n can be used for pressure measurement, liquid supplement or inert gas protection and the like.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention. In addition to the above embodiments, the present invention may have other embodiments, for example, the gas heater may be heated by a heating medium. All technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention. Technical features of the present invention which are not described may be implemented by or using the prior art, and will not be described herein.

Claims

1. A production system of PBS biodegradable materials comprises an esterification reaction kettle, and is characterized in that: the esterification reaction kettle comprises an esterification kettle A, an esterification kettle B and a second esterification kettle, wherein a slurry inlet at the top of the esterification kettle A is connected with a discharge hole of a first slurry preparation tank, a top inlet of the first slurry preparation tank is connected with a discharge hole of a first slurry preparation tank, and the top of the first slurry preparation tank is connected with a BDO feed pipe and is provided with a PTA feed port; a slurry inlet at the top of the esterification kettle B is connected with a discharge hole of a slurry preparation tank II, a top inlet of the slurry preparation tank II is connected with a discharge hole of a slurry preparation tank II, and the top of the slurry preparation tank II is connected with a BDO feed pipe and is provided with a dibasic acid feed port; the discharge ports of the esterification kettle A and the esterification kettle B are respectively connected with the feed port of the second esterification kettle, the discharge port of the second esterification kettle is connected with the feed port of the first polycondensation kettle through an esterification material pump, the discharge port of the first polycondensation kettle is connected with the feed port of the second polycondensation kettle through a first polycondensation material pump, the discharge port of the second polycondensation kettle is connected with the feed port of the final polycondensation reaction kettle through a second polycondensation material pump, and the discharge port of the final polycondensation reaction kettle is connected with the feed port of the tackifying reaction kettle through a melt conveying pump.

2. The system for producing a biodegradable material such as PBS according to claim 1, wherein: a discharge port of the tackifying reaction kettle is connected with a granulator I through a melt booster pump I; and the outlet of the melt conveying pump is connected with the feed inlet of the melt heat exchanger through a melt metering pump, the discharge outlet of the melt heat exchanger and the outlet of the chain extender adding system are connected with the inlet of the melt booster pump II together, and the discharge outlet of the melt booster pump II is connected with the granulator II.

3. The system for producing a biodegradable material such as PBS according to claim 2, wherein: the export of pelleter one and pelleter two links to each other with respective section middle storage bin respectively, the bottom of section middle storage bin is equipped with middle storage bin bleeder valve respectively, and the export of each middle storage bin bleeder valve links to each other with the section feed inlet at section drying tower top through wind respectively, and the section discharge gate of each section drying tower bottom links to each other with the entry of drying tower bleeder valve respectively, and the export of each drying tower bleeder valve links to each other with the section feed inlet at section drying tower two tops through wind respectively, and the section discharge gate of each section drying tower two bottoms links to each other with the main feed inlet of mixing bunker respectively, and the export of each mixing bunker links to each other with vacuum packaging machine respectively.

4. The system for producing a biodegradable material such as PBS according to claim 3, wherein: the tower body hot air outlet at the top of the first slicing drying tower and the top of the second slicing drying tower is connected with the air inlet of the dust remover through the dust removal suction pipe, the top air outlet of the dust remover is connected with the air supply port of the third air supply pipeline through the return air pipeline, the feed inlet of the third air supply pipeline is connected with the outlet of the slicing proportioning valve, the inlet of the slicing proportioning valve is connected with the outlet of the slicing proportioning hopper, and the outlet of the third air supply pipeline is connected with the auxiliary feed inlet of the mixing bin.

5. The system for producing a biodegradable material such as PBS according to claim 4, wherein: the main feed inlet is located mixing bunker's top center, assist feed inlet symmetric position the both sides of main feed inlet, mixing bunker's inner chamber is equipped with three compounding elephant trunks at least, and each compounding elephant trunk is followed vertical extension and is used the mixing bunker axis as central symmetric distribution, and the lower extreme of each compounding elephant trunk is crooked in fighting to the awl of mixing bunker bottom, evenly is equipped with a plurality of swift current material cross-sections along the direction of height of each compounding elephant trunk, and each swift current material cross-section is equipped with a swift current material mouth respectively, and each swift current material mouth is the heliciform along the circumference of compounding elephant trunk and distributes.

6. The system for producing a biodegradable material such as PBS according to claim 3, wherein: the first slicing and drying tower and the second slicing and drying tower respectively comprise a vertical cylindrical tower body, the center of the top of the tower body is provided with the slicing feed port, and the hot air outlet of the tower body is positioned on one side of the slicing feed port; the hot air inlet of the tower body is arranged at the lower part of the tower body, the drying tower cone hopper is connected to the bottom of the tower body, the slice discharge port is located at the lower end of the drying tower cone hopper, a plurality of distribution umbrella caps in a right circular cone shape are arranged along the axis of the tower body, besides the distribution umbrella caps at the top layer, baffle plates coaxial with the distribution umbrella caps are respectively arranged above the distribution umbrella caps and below the distribution umbrella caps at the bottom layer, and each baffle plate is in a horn mouth shape with a large upper part and a small lower part.

7. The system for producing a biodegradable material such as PBS according to claim 6, wherein: the upper end of each baffle plate is respectively connected to the inner wall of the tower body, each baffle plate is of a thin-wall cavity structure, the lower wall of each baffle plate is respectively connected with a corresponding baffle plate air supply ring pipe through a plurality of uniformly distributed radial communicating pipes, each baffle plate air supply ring pipe surrounds the periphery of the tower body and is respectively provided with a baffle plate hot air connector, and a plurality of baffle plate hot air holes are uniformly distributed on the upper wall of each baffle plate; the nitrogen pipe is connected with the air inlet of the gas heater, the air outlet of the gas heater is connected with the hot air main pipe, the hot air main pipe is respectively connected with the hot air branch pipes of each layer, the hot air branch pipes of each layer and the cold air branch pipes of the same layer are connected with the air supply pipe of the baffle plate of the layer, and the outlet of the air supply pipe of the baffle plate of each layer is respectively connected with the hot air interface of the baffle plate of the layer.

8. The system for producing a biodegradable material such as PBS according to claim 6, wherein: the diameter of the upper end of the drying tower cone hopper is larger than that of the tower body, the lower end of the tower body is inserted into the upper port of the drying tower cone hopper, an annular sealing cover is arranged at the upper port of the drying tower cone hopper, and the inner edge of the annular sealing cover is welded on the outer wall of the tower body; the annular cavity below the annular sealing cover is connected with a tower body air supply ring pipe through a plurality of radial communicating pipes which are uniformly distributed, the circumference of the tower body air supply ring pipe is provided with the tower body hot air inlet, and an annular hot air channel with a downward opening is arranged between the lower port of the tower body and the inner wall of the drying tower cone hopper.

9. The production system for a PBS-based biodegradable material according to any one of claims 1 to 8, wherein: the gas phase outlets of the first polycondensation kettle, the second polycondensation kettle, the final polycondensation reaction kettle or the tackifying reaction kettle are respectively connected with the side wall inlets of the vacuum catchers, the top gas phase port of each vacuum catcher is respectively connected with the gas inlet of the scraper condenser, the bottom outlet of each vacuum catcher is respectively connected with the top inlet of the vacuum collection tank through an electric cut-off valve, the top gas inlet of each vacuum collection tank is also connected with a nitrogen pipe through a nitrogen valve of the collection tank, and the bottom of each vacuum collection tank is respectively provided with a discharge valve of the collection tank; the medium outlet of each scraper condenser is respectively connected with the respective hot well through an atmospheric leg, the liquid phase outlet of each hot well is connected with the inlet of a spraying circulating pump, and the outlet of the spraying circulating pump is connected with the spraying port of the scraper condenser through a circulating liquid cooler.

10. The system for producing the PBS biodegradable material according to claim 9, is characterized in that: the top of the hot well is provided with a hot well top cover, a longitudinal clapboard is arranged along the longitudinal axis of the hot well to divide the inner cavity of the hot well into a left half and a right half, a left inner chamber and a right inner chamber are symmetrically arranged at two sides of the middle section of the longitudinal clapboard, the outer side of the transverse wallboard of the left inner chamber is a left outer chamber, the outer side of the transverse wallboard of the right inner chamber is a right outer chamber, the bottoms of the left inner chamber and the right inner chamber are respectively provided with a conical hopper, the lowest part of the two conical hoppers is respectively connected with a hot well slag discharge port, and the two hot well slag discharge ports respectively extend downwards to; the bottoms of the left outer chamber and the right outer chamber are respectively provided with the hot well liquid phase outlets; the hot well top cover is spliced with two atmospheric legs, the lower ends of the two atmospheric legs are respectively inserted into the lower parts of the inner cavities of the left inner chamber and the right inner chamber, the upper part of each transverse wallboard is respectively provided with an overflow port communicated with the corresponding outer chamber, the inner port of each overflow port is respectively covered with a filter plate, the left side and the right side of each filter plate are respectively spliced in the vertical slots on the inner end surfaces of the transverse wallboards, the outer port of each overflow port is respectively covered with an outward-protruding arc-shaped filter basket, and the left side and the right side of each arc-shaped filter basket are respectively spliced in the vertical slots on the outer end surfaces of the transverse wallboards.

11. The system for producing the PBS biodegradable material according to claim 10, is characterized in that: the hot well slag discharge port is respectively connected with a cleaning box feed inlet at the top of the cleaning box, the cleaning box comprises a horizontal barrel with one end closed, a cleaning box sealing cover capable of being opened and closed is hinged to the front end port of the cleaning box, a cleaning box jacket is coated on the periphery of the barrel of the cleaning box, a plurality of square filtering drawers which are sequentially superposed are arranged in an inner cavity of the cleaning box from top to bottom, frames on the left side and the right side of each square filtering drawer are respectively supported in guide chutes through rollers, each guide chute extends along the axial direction of the cleaning box and is respectively fixed on two sides of the inner wall of the cleaning box, an arc bottom drawer is arranged at the bottom of the inner cavity of the cleaning box, the bottom of the arc bottom drawer is supported at the bottom of the inner wall of the cleaning box through rollers, filter screens are respectively arranged at the bottoms of the arc bottom drawer and the square filtering drawers, and the mesh number of the lower filter screen is sequentially larger than that of, the lower end of the feed inlet of the cleaning box points to the central area of the square filter drawer at the top layer, and the bottom center of the cleaning box is provided with a liquid discharge port of the cleaning box.