KR100693300B1 - Poly latic acid manufacturing apparatus using vertical type centrifugal and method - Google Patents

Abstract

Provided are an apparatus for preparing poly(lactic acid) which is a biodegradable plastic having a high molecular weight, a high transparency and a strong heat resistance, and its method. The apparatus comprises a mixing unit(10) which comprises a corn starch supply device(11), a corn starch and water mixing device(12) and a stirring tank(14); a fermentation unit(20) which comprises a fermentation tank(21) provided with a stirrer(22) and an injection hole(23) at the upper central part; a first polymerization unit(30) which is provided with an electrodialysis device(31) and a discharge pipe(37); a second polymerization unit(40) which comprises a second polymerization tank connected to the discharge pipe and comprising a stirrer, a nitrogen injection hole and a heat exchanger at the upper part and a transfer pipe(45) at the lower part, a heating jacket installed at the surroundings of the second polymerization tank and a recovery tank installed at one end of the heat exchanger; a centrifugation unit(50) which comprises a screw and an internal space at the inside, and is provided with a heater, the transfer pipe(45) at the upper part of the internal space and a discharge pipe(55) whose one side is provided to the lower part of the internal space through an inlet and whose other side comprises the discharge pipe(55) connected to an extrusion unit(60); an extrusion unit(60) which is provided with a motor and an extrusion mold having a temperature control device; a cooling unit(70); and a cutting unit(80).

Description

Poly lactic acid manufacturing apparatus using vertical type centrifugal and method

1 is an overall configuration showing a polylactic acid production apparatus using a vertical high temperature special centrifugal separator according to the present invention,

Figure 2 is a block diagram showing the fermentation means of the polylactic acid production apparatus using a vertical high temperature special centrifugal separator according to the present invention,

3 is a block diagram showing the primary polymerization means of the polylactic acid production apparatus using the vertical high temperature special centrifugal separator according to the present invention,

Figure 4 is a block diagram showing the secondary polymerization means and centrifugation means of the polylactic acid production apparatus using the vertical high temperature special centrifugal separator according to the present invention,

Figure 5 is a block diagram showing the extrusion means, cooling means and cutting means of the polylactic acid production apparatus using a vertical high temperature special centrifugal separator according to the present invention,

6 is a process chart showing a method for producing polylactic acid using a vertical high temperature special centrifugal separator according to FIG. 1.

* Explanation of symbols on the main parts of the drawing

10: mixing means 11: fixed-quantity supply device 12: mixing device

14: stirring tank 15, 22: agitator 16, 23: inlet

20: fermentation means 21: fermentation tank 24: fermentation broth supply pipe

25 filtration device 26 lactic acid transfer pipe 30 primary polymerization means

31: electrodialysis apparatus 32: lactate separator 33: lactic acid purifier

34: primary polymerization tank 35: lactic acid supply pipe 36: reflux supply pipe

37: discharge pipe 40: secondary polymerization means 41: secondary polymerization tank

42 heat exchanger 43 recovery tank 44 heating jacket

45: transfer pipe 46, 56: high temperature gear pump 50: centrifugal separation means

51 screw 52 heater 54 recovery tank

60: extrusion means 61: motor 62: extrusion mold

70: cooling means 71: injector 80: cutting means

The present invention relates to a biodegradable plastic production apparatus and a manufacturing method using a vertical high-temperature special centrifuge to produce a polylactic acid (Poly Latic Acid), a biodegradable synthetic polymer synthesized by polycondensation of lactic acid.

Biodegradable plastic is a plastic that is decomposed by the action of microorganisms found naturally, such as bacteria, fungi and algae.It maintains the same physical properties as general-purpose plastics during use, but when disposed of or discarded after use It refers to a resin that is completely decomposed into water and carbon dioxide by microorganisms (bacteria, fungi and algae) present in nature.

Plastics are widely used throughout our lives so that modern society can be called the plastic age. Due to its light and strong characteristics, plastic products are used in various fields as materials for various household goods, home appliances, industrial materials, medical devices, and leisure products, and even today, many decades after industrialization, both production and consumption have increased greatly. . However, since most of synthetic resins (PE, PP, PVC, PS, PET, etc.) that are widely used in general are not decomposed in the natural environment, how to handle large amounts of plastic waste discarded after use is a big social problem. .

In particular, synthetic resins are widely used in everyday life, and due to their light weight, they are recognized as the main contributors to the environment because they are more noticeable than the amount actually thrown away. (E.g. various plastic bags, wrapping paper, styrofoam, etc.)

There are also hundreds of thousands of tons of plastic products (various waste plastics, fishing nets, fishing lines, etc.) spilled into the sea, and these wastes accumulate in the ocean, causing a lot of damage to fisheries and marine ecosystems.

Polylactic acid has been known to be able to obtain lactic acid by lactic acid fermentation by acting lactic acid bacteria to vegetable starch, which has been decondensation polymerization of lactic acid. However, according to the conventional method, the pH of the reaction solution decreases during the fermentation process, and the activity of the lactic acid bacteria is often inhibited, and it is difficult to efficiently obtain a high concentration of lactic acid efficiently.

It is speculated that the lowering of the pH of the reaction solution is caused by the remaining of the lactic acid produced by the fermentation in the fermenter when the vegetable starch and the lactic acid bacteria are acted upon.

In addition, polylactic acid is known to be obtained by dehydrogenation-condensation polymerization of lactic acid by appropriately adding a catalyst to the concentrated lactic acid and heating with stirring. At this time, it is necessary to discharge the water generated in the deshrinkage polymerization reaction to the outside of the apparatus, and as described in Japanese Patent Laid-Open Publication No. 2003-335850, conventionally a method for releasing water under reduced pressure as a method of discharging such water It is used.

However, according to the method of evaporating the water under reduced pressure, as the polymerization reaction proceeds, since the viscosity of the polymer becomes high, the dissociation rate of the water becomes low and efficient dehydration is impossible.

In addition, in the prior art, the polylactic acid is purified again through the dissolution process in the catalyst separation method, so it is repeated from the extrusion to the cutting of the product. have.

In order to solve the problems as described above, in the present invention, the polylactic acid prepared after the first polymerization process using corn starch and lactic acid to secondary polymerization to increase the molecular weight and centrifuged at high temperature to give a catalyst that was introduced into the polylactic acid. It is an object of the present invention to provide an apparatus and method for producing high quality polylactic acid having high molecular weight and high transparency by separation and purification.

In the configuration of the present invention for achieving the object, the quantitative supply device 11 for supplying corn starch and the mixing device 12 and the supply pipe 13 for mixing the corn starch and water and the agitator ( 15) and a mixing means (10) consisting of a stirring tank (14) having an inlet (16), a fermentation means (20) provided with a stirrer (22) and an inlet (23) in the upper center of the fermentation tank (21); In the polylactic acid production apparatus 100 consisting of a lactic acid storage means 30 consisting of a condensation part 31 and a storage tank 36 provided with a lactic acid discharge pipe 37 in the lower portion; It is connected to the discharge pipe 37 provided in the lower portion of the primary polymerization means 30, the stirrer 411 and the nitrogen inlet 412 and the heat exchanger 42 is installed on the upper portion and the transfer pipe 45 is connected to the lower Secondary polymerization tank 41, the secondary polymerization tank composed of a heating jacket 44 provided in the circumferential direction of the secondary polymerization tank 41, and the recovery tank 43 provided at one end of the heat exchanger (42) Means 40; The transfer pipe 45 is installed in the upper portion of the inner space 53 through the inlet 531, one side is provided to the lower portion of the inner space 53 through the inlet 531, the other side is discharge pipe connected to the extrusion means (60) (55), a heater (52), a centrifugal separation means (50) provided with a screw (51) and an inner space (53) inside, and a motor (61) connected to one side of the discharge pipe (55). And the other side is an extrusion means 60 composed of an extrusion mold 62 with a temperature control device having a plurality of circular holes 621, and an injector 71 and a conveyor 72 for injecting the air and water. Cooling means 70 provided with; Cutting means 80; characterized in that comprises a.

Here, the centrifugal separation means 50 is provided with a heater 52 in the outer circumferential direction, the recovery tank 54 is connected to the recovery pipe 541 provided at the bottom, is installed in the vertical direction, the discharge pipe 55 ) And the transfer pipe 45 is attached to a temperature control device provided with a heating wire, characterized in that the high heat gear pump 46 is provided.

In the production method of the present invention for achieving the object mixing step (S10) for mixing the corn starch and water to make the liquid sugar by adding enzymes to the mixed corn starch and water; A fermentation step (S20) in which the liquid sugar from the mixing step (S10) is added and the lactic acid bacteria are added and fermented by heating, and the fermentation broth is filtered from the impurities to form lactic acid as a fermentation filtrate; In the polylactic acid production method produced by the primary polymerization step (S30) for polymerizing the lactic acid from the fermentation step (S20) by heating the acid produced by the lactic acid separator 32 and the lactic acid concentrator (33); Adding a nitrogen to the first polymerized polylactic acid and maintaining a high temperature of 150 ° C. to 250 ° C., followed by a second polymerization step (S40); A centrifugation step (S50) of separating the second-polymerized polylactic acid after the second polymerization step (S40) into a polylactic acid and a catalyst by a difference in centrifugal force and specific gravity using a centrifugal means (50) for high heat; An extrusion step (S60) of maintaining the high temperature state by the temperature control device after the centrifugal separation step (S50) and pressing the motor 61 and extracting the polylactic acid extruded by the extrusion mold 62; A cooling step (S70) of cooling the polylactic acid extruded in the extrusion step (S60) by an injector (71) injecting air and water while transferring the polylactic acid to the feeder (72); And a cutting step (S80) of cutting the polylactic acid cooled by the cooling step (S70) into small pieces using the cutting means (80).

In addition, the centrifugation step (S50) is characterized in that the polylactic acid secondary polymerization at 150 ~ 250 ℃ in a high temperature state centrifuged in a high temperature state of 150 ~ 250 ℃ by a heater provided in the centrifugation means. .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an overall configuration showing a biodegradable plastic manufacturing apparatus using a vertical high temperature special centrifuge according to the present invention, Figure 2 is a fermentation means of a biodegradable plastic manufacturing apparatus using a vertical high temperature special centrifuge according to the present invention 3 is a block diagram showing a primary polymerization means of a biodegradable plastic manufacturing apparatus using a vertical high temperature special centrifuge according to the present invention, Figure 4 is a vertical high temperature special centrifuge according to the present invention Figure 2 is a block diagram showing the secondary polymerization means and centrifugation means of the biodegradable plastics manufacturing apparatus using, Figure 5 is an extrusion means, cooling means and cutting of the biodegradable plastics manufacturing apparatus using a vertical high temperature special centrifugal separator according to the present invention Figure 6 is a block diagram showing the means, Figure 6 is a biodegradable flask using a vertical high temperature special centrifuge according to Figure 1 A process chart showing a manufacturing method.

1 is an overall configuration showing a biodegradable plastic manufacturing apparatus according to the present invention, the biodegradable plastic manufacturing apparatus 100 is largely mixing means 10, fermentation means 20, primary polymerization means 30, secondary It comprises a polymerization means 40, centrifugation means 50, extrusion means 60, cooling means 70, cutting means (80).

The mixing means 10 is a quantitative supply device 11 for supplying corn starch in a fixed amount by the driving of the motor, and a mixing device 12 for mixing the corn starch and water introduced by the quantitative supply device 11 It is composed of, through the supply pipe 13 connected to the mixing device 12 is introduced into the stirring tank 14, the corn starch and water with the stirrer 15 provided in the upper center and the inlet 16 continuously The liquid sugar produced by adding and stirring the enzyme and the additive is supplied to the fermentation means 20 through the liquid sugar supply pipe 17 configured under the stirring tank 14.

Referring to Figure 2, the fermentation means 20 is connected to the liquid sugar supply pipe 17, the stirrer 22 is provided in the upper center and the fermentation tank equipped with an inlet 23 for injecting lactic acid bacteria, additives and nutrients ( 21, the two filtration device 25 is installed at a predetermined distance of the fermentation tank 21 and provided with connecting pipes (251, 252) is provided with a supply pipe provided in the lower portion of the fermentation tank (21) The lower connection pipe 252 connected to the upper connection pipe 24 and the lower connection pipe 251 is provided in the lower portion of the filtering device 25 is connected to the lactic acid transport pipe (26).

Referring to FIG. 3, the primary polymerization means 30 includes an electrodialysis apparatus 31 composed of a lactate separator 32 and a lactic acid purifier 33 connected to the lactic acid transport pipe 26, and one side of the lactic acid purifier. The lactic acid supply pipe (35) provided at (33) is connected to the primary polymerization tank (34), and the other side is provided with a reflux supply pipe (36), and the discharge tank (37) is provided at the lower portion of the storage tank (34).

Here, the electrodialysis apparatus 31 is provided with a central partition wall 321 and an anion permeable membrane 322 on both sides, and one side is provided with a sulphate solution tube 325, and the other side is provided with a desulphate tube 326. It is connected to the reflux supply pipe 36, one side of the anode 324 is formed and the other side of the lactate separator 32 is formed, and two partitions 321 are installed in the center and the partition 321 The lactic acid solution pipe (3425) is connected between the anion permeable membrane 322 is installed on both sides is provided with a lactic acid supply pipe 35 on the anode 324 formed on one side is connected to the storage tank 34 and the other side The formed negative electrode 323 is provided with an alkaline liquid pipe 331 is composed of a lactic acid purifier 33 connected to the reflux liquid supply pipe (36).

Looking at the configuration after the first polymerization means 30 of the present invention with reference to Figure 4, the secondary polymerization means 40 is a secondary polymerization connected to the discharge pipe 37 provided below the primary polymerization tank 34 A heat exchanger 42 fixed to the connection pipe 421 is provided on the upper part of the tank 41, and a recovery tank 43 is provided on one side of the heat exchanger 42, which is used at a high temperature in the secondary polymerization tank 41. Moisture or other impurities evaporate when they are polymerized, thereby accepting the evaporated moisture or impurities through the connection pipe 421 and changing the water and impurities in the gaseous state evaporated through the heat exchanger 42 into a liquid state. It is to recover to the recovery tank 43 provided at the end.

In addition, the heating jacket 44 having the heating jacket 44 in the circumferential direction of the secondary polymerization tank 41 is to continue to apply the heat so as to polymerize at a high temperature and the lower conveying pipe 45 is connected to the extrusion means 70 In addition, a high heat gear pump 46 is provided between the transfer pipe 45 and the extrusion means 70, which is a gear pump made of a special steel that is capable of withstanding high temperatures in order to transfer high temperature secondary polymerized polylactic acid. It is preferred to use a temperature control device (not shown) to provide a temperature control device (not shown) in the transfer pipe (45) to prevent the temperature is hardened during the transfer to harden the heat pipe (not shown) ) To maintain a desired temperature.

The centrifugal separation means 50 is installed vertically and is provided with a heater 52 in the outer circumferential direction so as to maintain a temperature of 150 to 250 ° C., which is a temperature at the time of secondary polymerization, in the secondary polymerization means 40 and Screw 51 provided in the high-speed rotation at 1500 ~ 3000rpm and the transfer pipe 45 is configured to be installed in the inner space 53 through the inlet 531 provided on the upper side, one side is the inlet 531 The discharge pipe 55 is provided to the lower portion of the inner space 53 and the other side is connected to the extrusion means 60, the discharge pipe 55 is equipped with a temperature control device provided with a heating wire is the centrifugation means 50 and the extrusion means 60 A high temperature gear pump 46 is provided in between, and a recovery tank 54 connected to the recovery pipe 541 is provided at the bottom thereof, which is used to determine the difference in specific gravity when the centrifugal separation means is centrifuged by centrifugal force when rotating at high speed. Device for separating and recovering the separated catalyst All.

The extrusion means 60 is connected to the transfer pipe 55, one side is provided with a motor 61 is driven to extrude the polylactic acid, the other side is formed with a plurality of circular holes 621, the temperature control device is attached It is composed of an extrusion mold 62, wherein the temperature control device is attached to the extrusion mold 62, the polylactic acid is transferred to the extruded means 60 is separated from the catalyst at a high temperature state in the centrifugation means (50) Although not shown in order to prevent the polylactic acid from being extruded in a solid state when the temperature is lowered during the transfer to a), the heating wire is wound to maintain a desired temperature.

The cooling means 70 is to inject air and water by a plurality of nozzles (711) provided in the injector 71, and the transfer means 72 is provided to cut the cooled polylactic acid cut means (80) Will be transferred to).

The polylactic acid thus transferred is continuously cut by a rotary cutter (not shown) configured to rotate in a cooled state in the cutting means 80 and cut into small pieces.

FIG. 6 is a process diagram illustrating a method of manufacturing a polylactic acid as a biodegradable plastic according to FIG. 1. Referring to this, the mixing step (S10) is a process of mixing corn starch, water, an additive, and enzymes. Corn starch is introduced into the mixing device 12 through the device 11 to mix corn starch and water, and the mixed corn starch and water are stirred tank equipped with the stirrer 15 through the supply pipe 13. When it is added to (14), the enzymes and additives are introduced through the inlet 16 and stirred by the stirrer 15, the liquid sugar per liquid is introduced into the fermentation process (S20) through the liquid sugar supply pipe 17.

Herein, the mixing ratio (mass ratio) of corn starch and lactic acid bacteria is preferably 1000: 0.1 to 1000: 10, more preferably 1000: 0.5 to 1000: 5, and the additives exemplify diet, calcium carbonate, various enzymes, and the like. The content of the calcium carbonate is preferably 0.5 to 1% by mass based on the mixture.

The fermentation filtration process (S20) is a liquid sugar introduced into the fermentation tank 21 through the liquid sugar supply pipe 17 through the inlet 23 is added to the lactic acid bacteria through the heating and stirred with the stirrer 22 to ferment the liquid sugar. During fermentation, the temperature is about 40 ℃ and the acidity (PH) of the mixture is maintained at about 5 ~ 6. The fermentation is carried out for several hours, and the fermentation is made to produce lactic acid as a fermentation filtrate by filtering out impurities or solids. The fermented liquid in the means 20 is sent to the supply pipe 251 through the fermentation broth supply tube 24 to produce a lactic acid as a fermentation filtrate due to the filtration of the filtration device 25 and the resulting lactic acid is provided on the lower side Through the lactic acid transfer pipe 26 in the connecting pipe 252 is sent to the next step of the first polymerization process (S30).

The primary polymerization process (S30) is composed of an electrodialysis apparatus 31 composed of a lactate separator 32 and a lactic acid purifier 33 for dewatering the filtered lactic acid, the lactate separator 32 is fermented with water The lactic acid separated through the lactic acid transfer pipe (26) is introduced into the lactic acid separator (32) is electrolyzed around the partition 321, the dehydration dehydrated dehydration pipe in the positive electrode (324) ( 326 is re-supplied to the fermentation means 20 through the reflux solution supply pipe 36, the lactate is generated in the cathode 323 formed on the other side of the partition wall 321 through the lactate liquid pipe 325 Lactic acid produced by (33) When the lactate solution is introduced between the partition walls 321 provided on both sides of the lactic acid refiner 33, the lactic acid of a high concentration is generated in the anode 324 by electrolysis as the lactate separator 32. And supplied to the first polymerization tank 34 through the lactic acid supply pipe 35 and the cathode (3) 23, the other mixture is separated and recovered to the fermentation tank 21 through the reflux liquid return pipe 36.

In addition, in the primary polymerization tank 34, the catalyst is added together to the high concentration of lactic acid separated by the electrodialysis apparatus 31 to heat the primary catalyst and the high concentration of lactic acid to perform the primary polymerization. The mixing ratio (mass ratio%) of lactic acid and primary catalyst is preferably 100: 1 to 100: 10, and more preferably 100: 3 to 100: 5. The catalyst can be used without particular limitation as long as it is a catalyst used for polymerization of lactic acid. For example, it is preferable to mix ruthenium oxide and titanium oxide at 50 mass%.

It will be described below the manufacturing method according to the present invention.

As described above, the polylactic acid polymerized first through the mixing process (S10), the fermentation process (S20) and the first polymerization process (S30) contains about 10% of impurities, so that the molecular weight is low and the transparency is not clear. Therefore, the molecular weight is high through the secondary polymerization step (S40), centrifugation step (S50), extrusion step (S60), cooling step (S70) and cutting step (S80) as follows to increase the molecular weight and transparency 1 It is to improve the transparency by removing the impurities and catalyst contained in the secondary polymerization step (S30).

The secondary polymerization process (S40) is a heating jacket provided inside the secondary polymerization tank (41) when the polylactic acid in the primary polymerization process (S30) is introduced into the secondary polymerization tank (41). Maintain high heat of 150 ℃ ~ 250 ℃ through the nitrogen gas inlet 412 to 3 to 5 liters per minute (L) and agitated using a stirrer 411 and the first polymerized polylactic acid In the high temperature state 150 to 250 ℃ to promote the polymerization to increase the molecular weight and the secondary polymerized high temperature polylactic acid is transferred to the heating pipe provided in the temperature control device using a high temperature gear pump 46 ) To be supplied to the centrifugation process (S50) while being adjusted to a desired temperature of 150 ~ 250 ℃ temperature range.

The centrifugation step (S50) is a centrifugal separation of the secondary polymerized polylactic acid by the centrifugation means (50) because the polylactic acid produced in the second polymerization step (S40) contains a catalyst as it is Must be separated correctly.

Therefore, the polylactic acid after the second polymerization is managed at 150 ~ 250 ℃, vertical heating while maintaining the 150 ~ 250 ℃ through the transfer pipe 45 equipped with a high temperature gear pump 46 and a temperature control device Supply to the centrifuge means (50).

The vertical centrifugation means 50 is a heater 52 capable of continuously heating the surface to maintain the internal temperature of the centrifugation means 50 at 150 to 250 ° C., such as secondary polymerization, and to rotate at a high speed. It is to separate the catalyst and the polylactic acid by separating the catalyst by centrifugation by. The separated catalyst is recovered to the recovery tank 54 through the recovery pipe 541 and the recovered catalyst can be collected and recycled.

In addition, the separated catalyst is collected and used as recyclable, and the purified polylactic acid is managed at a temperature range of 150 to 250 ° C. The purified polylactic acid by centrifugation is transferred to a high temperature vessel pump 56 and heated. Maintain a temperature of 150 ~ 250 ℃ through the discharge pipe 55 is equipped with a temperature control device equipped with this is transferred to the extrusion process (S60).

The extrusion step (S60) is to make a polylactic acid having a higher molecular weight by the motor 61 provided on one side to make the second polymerized polylactic acid into a harder polylactic acid through the extrusion means (60). It is also extruded like a thin noodle by drawing it into the extrusion mold 62.

Here, the extrusion mold 62 is provided with a plurality of circular holes 621, the temperature control device (Electric Heater Control) capable of temperature control pellet dies (Pellet Dies) processed about 10 to 500 holes of 3 ~ 5mm ) To maintain the proper temperature 150 ℃ ~ 250 ℃ by the motor 61 is extruded in an appropriate amount (1 ~ 10000kg / hr).

On the other hand, the transfer pipe 45, the discharge pipe 55 and the extrusion mold 62 is preferably provided with an electric heater device which is a temperature control device capable of temperature control, the temperature control device is the transfer pipe 45 or The temperature is controlled by winding a heating wire to generate heat in the extrusion mold 62. The temperature controller is a polylactic acid polymerized at a high temperature so that the temperature in the transfer pipe 45 or the discharge pipe 55 and the extrusion mold 62 is increased. Is to prevent the hardening

In addition, the secondary polymerization step (S40), the centrifugation step (S50) and the extrusion step (S60) to the temperature range of 150 ℃ ~ 250 ℃ by the secondary polymerization step (S40) in the secondary polymerization at the temperature range In addition, in the centrifugation process (S50), centrifugation may result in an optimum viscosity state in the temperature range during centrifugation due to specific gravity. If higher or lower, the viscosity state becomes unstable and the centrifugation is well performed. It is not made, the extrusion process (S70) also during extrusion the temperature range is the optimal extrusion conditions.

After the extrusion step (S70) in the cooling step (S70) by spraying water and air by spraying the water and air by the nozzle 711 provided in the injector 71, the polylactic acid extruded like noodles using a blower (not shown) By drying the water and conveyed to the conveying means 72 is transferred to the cutting step (S80) of the next step.

The cutting process (S80) is a process of continuously cutting to a suitable diameter of φ3 ~ 5 x 2 ~ 5mm using a rotary cutter (rotary cutter) for rotating the cooled polylactic acid.

As described above, preferred embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments, and the present invention belongs to the present invention without departing from the gist of the present invention as claimed in the following claims. Anyone with ordinary knowledge will have the technical spirit of the present invention to the extent that various modifications can be made.

As described in detail above, the present invention can suppress the emission of harmful substances in the manufacturing process by using environmentally friendly materials using corn starch and lactic acid and secondary polymerization of polylactic acid polymerized first after the first polymerization process By increasing the molecular weight and centrifuging at high temperature, the catalyst injected into the polylactic acid is separated and purified to produce polylactic acid, a high molecular weight and high transparency, biodegradable plastic. It can be used in food containers, agricultural films, etc. It is an eco-friendly process without using organic solvents, and it is possible to perform all processes continuously without repeating processes, which increases the production efficiency.

Claims (5)

Stirring tank 11 for supplying corn starch and mixing device 12 for mixing the corn starch and water is connected to the supply pipe 13, the stirring tank having a stirrer 15 and the inlet 16 in the upper center Mixing means (10) consisting of (14), fermentation means (20) equipped with a stirrer (22) and inlet (23) in the upper center of the fermentation tank (21), the electrodialysis apparatus (31) and the discharge pipe (in the lower part) In the polylactic acid production apparatus 100 including a primary polymerization means 30 composed of a primary polymerization tank 34 having a 37); Connected to the discharge pipe 37 provided in the lower portion of the primary polymerization means 30, the stirrer 411 and the nitrogen inlet 412 and the heat exchanger 42 is installed on the upper portion and the transfer pipe 45 is connected to the lower Secondary polymerization tank 41, the secondary polymerization tank composed of a heating jacket 44 provided in the circumferential direction of the secondary polymerization tank 41, and the recovery tank 43 provided at one end of the heat exchanger (42) Means 40; A screw 51 and an inner space 53 are provided on the inner side, and a heater 52 is provided, and the transfer pipe 45 is installed on the inner space 53 through the inlet 531, and one side of the inlet 531 is provided. And a centrifugal separation means (50) consisting of a discharge pipe (55) connected to the extrusion means (60) and provided to the lower portion of the inner space (53) through; An extrusion means (60) connected to the discharge pipe (55) and provided with a motor (61) on one side and an extrusion mold (62) having a temperature control device having a plurality of circular holes (621); Cooling means (70) having an injector (71) and a conveyor (72) for injecting the air and water; Cutting device (80); Polylactic acid production apparatus using a vertical high temperature special centrifugal separator comprising a. The method of claim 1, The centrifugal separation means 50 is provided with a heater 52 in the outer circumferential direction, the recovery tank 54 is connected to the recovery pipe 541 provided on the lower, vertical type, characterized in that installed in the vertical direction Polylactic acid production apparatus using a high temperature special centrifuge. The method of claim 1, The discharge pipe 55 and the transfer pipe 45 is a polylactic acid production apparatus using a vertical high temperature special centrifugal separator, characterized in that the temperature control device provided with a heating wire is attached and the high heat gear pumps 46 and 56 are provided. . Mixing cornstarch and water, and adding an enzyme to the mixed cornstarch and water to make a liquid sugar (S10); A fermentation step (S20) in which the liquid sugar from the mixing step (S10) is added and the lactic acid bacteria are added and fermented by heating, and the fermentation broth is filtered from the impurities to form lactic acid as a fermentation filtrate; In the method of producing a polylactic acid produced by the primary polymerization step (S30) in which the lactic acid from the fermentation step (S20) is polymerized by the primary polymerization means (30) via the electrodialysis apparatus (31); A second polymerization step (S40) of adding nitrogen to the first polymerized polylactic acid and stirring and maintaining the polymer at a high temperature of 150 to 250 ° C .; A centrifugation step (S50) of separating the polylactic acid and the catalyst by a difference between the centrifugal force and the specific gravity by using the second polymerization step (S40) and the second polymerized polylactic acid using a centrifugal means (50) for high heat; An extrusion step (S60) of maintaining the high temperature state by the temperature control device after the centrifugal separation step (S50) and pressing the motor 61 and extracting the polylactic acid extruded by the extrusion mold 62; A cooling step (S70) of cooling the polylactic acid extruded in the extrusion step (S60) by an injector (71) injecting air and water while transferring the polylactic acid to the feeder (72); Method for producing a polylactic acid using a vertical high-temperature special centrifuge, characterized in that it is manufactured by; cutting step (S80) for cutting the polylactic acid cooled by the cooling step (S70) using a cutting means (80) . The method of claim 4, wherein The centrifugation step (S50) is centrifugation by specific gravity in a high temperature state of 150 ~ 250 ℃ by the heater 52 provided in the centrifugation means 50 to the secondary polymerization polylactic acid at 150 ~ 250 ℃ high temperature Method for producing a polylactic acid using a vertical high temperature special centrifuge, characterized in that the separation.

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