Purifying device for 1, 3-propylene glycol

Abstract

The utility model relates to the technical field of biochemical engineering, and discloses a 1, 3-propylene glycol purification device which comprises a heating unit and a decolorizing column, the heating unit is arranged at the feeding end of the decolorizing column and can heat 1, 3-propylene glycol entering the decolorizing column into a gaseous state, and a filler layer is arranged in the decolorizing column and used for filtering and treating the gaseous 1, 3-propylene glycol; according to the utility model, crude 1, 3-propylene glycol to be purified is heated by the heating unit to form a gas state, and then the gas state is introduced into the decolorizing column provided with the filler layer, so that the 1, 3-propylene glycol is contacted with the filler in the filler layer in a larger contact area, the mass transfer speed is improved, and the 1, 3-propylene glycol can be more efficiently removed. The impurities are contained in 1, 3-propylene glycol.

Description

Technical Field

[0001] The utility model relates to the technical field of biochemistry, and particularly relates to a purification device for 1,3-propanediol. Background Art

[0002] 1,3-propanediol is a colorless, odorless, hygroscopic viscous transparent liquid. As a key raw material, 1,3-propanediol is widely used in cosmetics, inks, printing and dyeing, coatings, lubricants, etc., and is particularly widely concerned as a polyester monomer. In the field of biodegradation, bio-based 1,3-propanediol has great application potential. It can be polymerized with terephthalic acid to produce polytrimethylene terephthalate (abbreviation: PTT) with excellent properties, or participate in the copolymerization of PBAT, PBS and other degradable materials to synthesize new degradable copolyester materials. 1,3-propanediol can also be used as a raw material for polyesters and polyurethanes, replacing 1,4-butanediol and neopentyl glycol, etc. for the production of polyol polyesters and as a carbon chain extender. In addition, 1,3-propanediol can also be used in the fields of cosmetics and medicine, etc.

[0003] There are mainly three existing methods for preparing 1,3-propanediol: acrolein method, ethylene oxide method and microbial fermentation method. In addition to the target product 1,3-propanediol, the reaction solutions obtained by the above methods also contain unreacted raw materials, intermediate products and various by-products. For example, in the current industry, the microbial fermentation method is widely used to produce 1,3-propanediol. Through microorganisms consuming glucose or glycerol to metabolize 1,3-propanediol, in the fermentation broth obtained by fermentation, in addition to 1,3-propanediol and bacteria, there are also a large number of organic impurities. The residual organic pigments include impurities such as unsaturated aldehydes and ketones that are prone to oxidation and color change, which will seriously affect the use of 1,3-propanediol.

[0004] In addition, as a diol, 1,3-propanediol has strong water absorption. During use and long-term storage, it will absorb or generate a small amount of water and trace amounts of colorless and colored impurities, which will also have an adverse effect on the use of 1,3-propanediol. Therefore, it is also necessary to purify this part of 1,3-propanediol.

[0005] How to efficiently purify 1,3-propanediol and remove the impurities contained therein to ensure the reliability of subsequent use is a technical problem that those skilled in the art particularly concern. Summary of the Utility Model

[0006] The purpose of the utility model is to provide a purification device for 1,3-propanediol, and realize the efficient purification of 1,3-propanediol through this purification device.

[0007] To achieve the above object, the present utility model provides a purification device for 1,3-propanediol, comprising a heating unit and a decolorization column. The heating unit is arranged at the feed end of the decolorization column and can heat the 1,3-propanediol entering the decolorization column into a gaseous state. A packing layer is arranged in the decolorization column for filtering the gaseous 1,3-propanediol.

[0008] Preferably, the decolorization column extends in the vertical direction and has an air inlet at the lower end of the decolorization column and an air outlet at the upper end of the decolorization column. The gaseous 1,3-propanediol enters from the air inlet and flows out from the air outlet. A liquid collecting weir is arranged on the inner wall of the decolorization column below the packing layer. The liquid collecting weir extends circumferentially along the inner wall of the decolorization column. A drain port communicating with the liquid collecting weir is arranged on the decolorization column.

[0009] Preferably, a drain pipe extending into the liquid collecting weir is connected to the drain port, and a liquid suction pump is arranged on the drain pipe for sucking out the liquid-phase material in the liquid collecting weir.

[0010] Preferably, a plurality of packing layers are arranged, and the plurality of packing layers are arranged in sequence in the decolorization column along the flow direction of the gaseous 1,3-propanediol.

[0011] Preferably, a distributor is arranged on the feed side of the packing layer in the decolorization column for dispersing the gaseous 1,3-propanediol.

[0012] Preferably, a dust filtering layer is arranged on the discharge side of the packing layer in the decolorization column for intercepting and filtering the packing powder.

[0013] Preferably, a heat preservation structure is arranged outside the decolorization column.

[0014] Preferably, the heating unit comprises a rectification column with a reboiler. The top outlet of the rectification column is connected to the air inlet of the decolorization column through a first feed pipeline. The bottom outlet of the rectification column is connected to a first discharge pipeline with a first discharge valve. A branch pipeline is connected to the first discharge pipeline between the first discharge valve and the bottom outlet. The other end of the branch pipeline is connected to the inlet of the reboiler, and the outlet of the reboiler is connected to the lower reflux port of the rectification column.

[0015] Preferably, a plurality of decolorization columns are arranged in parallel, and the air inlets of the plurality of decolorization columns are respectively connected to the top outlet of the rectification column through the first feed pipeline.

[0016] Preferably, the heating unit further comprises a heater arranged on the first feed pipeline for heating the 1,3-propanediol flowing through the first feed pipeline.

[0017] Preferably, the purification device further includes:

[0018] a condenser, in which a heat exchange pipeline is arranged, the heat exchange pipeline is used to introduce a refrigerant to cool the material passing through the condenser, one end of the condenser is provided with a material inlet, the other end is provided with a material outlet, and the material inlet is communicated with the air outlet of the decolorizing column through a second feeding pipeline;

[0019] a gas-liquid separator, which is used to separate the gas and liquid of the material flowing out of the material outlet of the condenser; and

[0020] a vacuum pump, the air extraction port of the vacuum pump is communicated with the gas phase outlet of the gas-liquid separator, and is used to form a vacuum environment in the gas-liquid separator.

[0021] Preferably, the material inlet is communicated with the top outlet of the rectifying column through a third feeding pipeline; the liquid phase outlet of the gas-liquid separator is respectively connected with a reflux pipeline with a reflux valve and a second discharging pipeline with a second discharging valve, the other end of the reflux pipeline is connected to the upper reflux port of the rectifying column, and a reflux feeding pump is arranged on the reflux pipeline.

[0022] Preferably, a flow meter is arranged on the reflux pipeline.

[0023] Through the above technical solution, the crude 1,3-propanediol to be purified is heated by a heating unit to form a gas state, and then it is introduced into a decolorizing column provided with a packing layer, so that the 1,3-propanediol contacts with the packing in the packing layer with a larger contact area, improving the mass transfer rate, and thus being able to remove impurities in the 1,3-propanediol more efficiently. Description of the Drawings

[0024] Figure 1 is a schematic diagram of a purification device for 1,3-propanediol provided by the present invention.

[0025] Description of the Reference Numerals

[0026] 10. Decolorization column; 101. Inlet; 102. Outlet; 103. Drain port; 11. Packing layer; 12. Liquid collecting weir; 13. Drain pipe; 131. Liquid suction pump; 14. Distributor; 15. Dust filter layer; 16. Second feeding pipeline; 161. Second control valve; 17. Feeding pipeline; 171. Feeding valve; 20. Rectifying column; 201. Top outlet; 202. Bottom outlet; 203. Lower reflux port; 204. Upper reflux port; 21. First feeding pipeline; 211. First control valve; 22. First discharging pipeline; 221. First discharging valve; 23. Branch pipeline; 24. Third feeding pipeline; 241. Third control valve; 30. Reboiler; 40. Heater; 50. Condenser; 501. Material inlet; 502. Material outlet; 51. Fourth feeding pipeline; 511. Fourth control valve; 60. Gas-liquid separator; 61. Reflux pipeline; 611. Reflux valve; 612. Reflux feeding pump; 613. Flowmeter; 62. Second discharging pipeline; 621. Second discharging valve; 70. Vacuum pump; 71. Air extraction pipeline; 711. Air extraction valve. Detailed implementation manners

[0027] The following will describe in detail the specific implementation manners of the present utility model in conjunction with the accompanying drawings. It should be understood that the specific implementation manners described herein are only used to illustrate and explain the present utility model, and are not used to limit the present utility model.

[0028] Example 1

[0029] The present utility model provides a purification device for 1,3-propanediol, which can efficiently remove impurities in 1,3-propanediol through this purification device.

[0030] As Figure 1 shown, the purification device includes a heating unit and a decolorization column 10. The heating unit is arranged at the feeding end of the decolorization column 10 and can heat the 1,3-propanediol entering the decolorization column 10 into a gaseous state. A packing layer 11 is arranged in the decolorization column 10 for filtering and treating the gaseous 1,3-propanediol.

[0031] In the technical solution provided by the present utility model, the 1,3-propanediol to be purified is heated by the heating unit to form a gaseous state, and then it is introduced into the decolorization column 10 provided with the packing layer 11, so that the 1,3-propanediol contacts the packing in the packing layer 11 with a larger contact area, improving the mass transfer rate, and thus being able to more efficiently remove impurities in 1,3-propanediol.

[0032] In some embodiments, the decolorization column 10 extends in the vertical direction and has an air inlet 101 at the lower end of the decolorization column 10 and an air outlet 102 at the upper end of the decolorization column 10. Gaseous 1,3-propanediol enters from the air inlet 101 and flows out from the air outlet 102. A liquid collecting weir 12 is provided on the inner wall of the decolorization column 10 below the packing layer 11. The liquid collecting weir 12 extends circumferentially along the inner wall of the decolorization column 10, and a drain port 103 is provided on the decolorization column 10 and can communicate with the liquid collecting weir 12.

[0033] The inventors of the present application found that during the process of gaseous 1,3-propanediol passing through the decolorization column 10, partial liquefaction will occur. The partially liquefied 1,3-propanediol will be carried by the continuously introduced airflow and adhere to the inner wall of the decolorization column 10, thereby forming a liquid column and seriously affecting the filtration efficiency of the packing layer 11. In the present utility model, by setting the decolorization column 10 to extend in the vertical direction and cooperating with the liquid collecting weir 12 provided on the inner wall of the decolorization column 10 below the packing layer 11, the liquefied 1,3-propanediol is collected by the liquid collecting weir 12 and discharged through the drain port 103, effectively avoiding the problem that the liquefied 1,3-propanediol forms a liquid column in the decolorization column 10 and causes the filtration efficiency of the packing layer 11 for gaseous 1,3-propanediol to deteriorate.

[0034] It can be understood that the key to the setting of the liquid collecting weir 12 is to extend circumferentially along the inner wall of the decolorization column 10 so as to be able to fully collect the liquefied 1,3-propanediol.

[0035] The present utility model does not make special limitations on the specific structure of the liquid collecting weir 12. In a specific embodiment of the present utility model, the liquid collecting weir 12 includes a circular ring welded to the inner wall of the decolorization column 10 and a frustum of a cone provided inside the circular ring. The circular ring and the frustum of the cone form a accommodating space with a certain depth and capable of accommodating liquid-phase materials to accommodate the liquefied 1,3-propanediol.

[0036] Furthermore, in the present utility model, in order to facilitate the discharge of the liquid-phase material in the liquid collecting weir 12, that is, the liquefied 1,3-propanediol, a drain pipe 13 extending into the liquid collecting weir 12 is connected to the drain port 103, and a liquid suction pump 131 is provided on the drain pipe 13 to suck out the liquid-phase material in the liquid collecting weir 12.

[0037] It can be understood that for the convenience of operation, a sight glass can be installed in the decolorization column 10 at the position where the liquid collecting weir 12 is located. Through the sight glass, the operator can conveniently observe the liquid level in the liquid collecting weir 12. When the liquid-phase material reaches a certain liquid level, the liquid suction pump 131 is timely started to suck out the liquid-phase material.

[0038] In some embodiments, a plurality of the packing layers 11 are provided, and the plurality of the packing layers 11 are arranged in sequence in the decolorization column 10 along the flowing direction of gaseous 1,3 - propanediol; it can be understood that by providing a plurality of packing layers 11 to sequentially filter gaseous 1,3 - propanediol, the filtering effect of 1,3 - propanediol is improved, and the quality of the purified 1,3 - propanediol is ensured.

[0039] Correspondingly, in the solution with a plurality of packing layers 11, in order to avoid the liquefied 1,3 - propanediol from affecting the filtering efficiency of the packing layer 11, a plurality of liquid collecting weirs 12 are provided. The plurality of liquid collecting weirs 12 correspond one - to - one with the plurality of packing layers 11. Each liquid collecting weir 12 is provided on the inner wall of the decolorization column 10 below the corresponding packing layer 11, and a drain port 103 corresponding to and communicating with the liquid collecting weir 12 is provided on the decolorization column 10 for timely discharging the liquid - phase material collected in the liquid collecting weir 12.

[0040] In some embodiments, a distributor 14 is provided on the feed side of the packing layer 11 in the decolorization column 10. The distributor 14 is used to disperse gaseous 1,3 - propanediol; by providing the distributor 14, the uniform distribution effect of gaseous 1,3 - propanediol in the decolorization column 10 is improved, so that the packing layer 11 can uniformly filter gaseous 1,3 - propanediol. It should be noted that the present utility model does not make special limitations on the structural form of the distributor 14, as long as it can make gaseous 1,3 - propanediol uniformly distributed in the decolorization column 10 to achieve uniform contact with the packing in the packing layer 11. The distributor 14 can adopt the commonly used gas distributors in the art, and the present utility model will not elaborate here.

[0041] In some embodiments, a dust filtering layer 15 is provided on the discharge side of the packing layer 11 in the decolorization column 10. The dust filtering layer 15 is used to intercept and filter the packing powder. It can be understood that by providing the dust filtering layer 15 to filter the air flow passing through the packing layer 11, the problem that the air flow carries out the packing powder in the packing layer 11 and mixes it in the filtered product is avoided. The present utility model does not make special limitations on the structural form of the dust filtering layer 15, and a commonly used dust filter net in the art can be adopted.

[0042] In some embodiments, a heat - preservation structure is provided outside the decolorization column 10. By providing the heat - preservation structure to perform heat - preservation treatment on the decolorization column 10, the problem that the gaseous 1,3 - propanediol entering the decolorization column 10 is liquefied due to temperature reduction, thereby reducing its contact efficiency with the packing layer 11 and resulting in a poor filtering effect is avoided. The present utility model does not make special limitations on the form of the heat - preservation structure. Exemplarily, the heat - preservation structure is a heat - preservation material wrapped outside the decolorization column 10.

[0043] In the present utility model, the heating unit can adopt any appropriate structural form as long as it can heat the 1,3-propanediol to be purified to form a gaseous state.

[0044] In some embodiments, the heating unit includes a distillation column 20 having a reboiler 30. The top outlet 201 of the distillation column 20 is connected to the air inlet 101 of the decolorizing column 10 through a first feed pipeline 21. The bottom outlet 202 of the distillation column 20 is connected to a first discharge pipeline 22 with a first discharge valve 221. A branch pipeline 23 is connected to the first discharge pipeline 22 between the first discharge valve 221 and the bottom outlet 202. The other end of the branch pipeline 23 is connected to the inlet of the reboiler 30, and the outlet of the reboiler 30 is connected to the lower reflux port 203 of the distillation column 20.

[0045] It can be understood that the distillation column 20 can not only heat the 1,3-propanediol to make it pass through the decolorizing column 10 in a gaseous form, but also perform a distillation operation on the 1,3-propanediol to remove impurities in the 1,3-propanediol. Through the distillation treatment of the distillation column 20, the light-phase components mainly composed of 1,3-propanediol are discharged from the top of the distillation column 20, and part of the 1,3-propanediol and impurities enter the bottom of the column as heavy-phase components. The heavy-phase components include unsaturated impurities, glycerol, 1,4-butanediol, 1,2-propanediol, etc.

[0046] The present utility model does not make special limitations on the structural form of the distillation column 20, and the structural form of the distillation column commonly used in the art can be selected, such as a plate column or a packed column.

[0047] It should be noted that the operating conditions of the distillation column 20 need to be adjusted adaptively according to the composition of the 1,3-propanediol. Exemplarily, the vacuum degree of the distillation column 20 is 200 - 300 par, the top temperature is 80 - 100 °C, the bottom temperature is 120 - 140 °C, and the reflux ratio is adjusted according to the purity of the 1,3-propanediol in the feed. When the equipment starts to run, full reflux is adopted, and after stabilization, the reflux ratio is lowered for discharging.

[0048] In some embodiments, a plurality of decolorizing columns 10 are arranged in parallel, and the air inlets 101 of the plurality of decolorizing columns 10 are respectively connected to the top outlet 201 of the distillation column 20 through the first feed pipeline 21.

[0049] Exemplarily, in combination with Figure 1As shown, for the convenience of control and to reduce the layout cost, only one first feed pipeline 21 is provided. The air inlets 101 of multiple decolorizing columns 10 are respectively and independently connected to the first feed pipeline 21 through feed pipelines 17, and a feed valve 171 is provided on the feed pipeline 17 to control the on-off. Correspondingly, in order to conveniently control the on-off of the first feed pipeline 21, a first control valve 211 is provided on the first feed pipeline 21.

[0050] In some embodiments, the heating unit further includes a heater 40 provided on the first feed pipeline 21. The heater 40 is used to heat the 1,3-propanediol flowing through the first feed pipeline 21. By providing the heater 40 to supplementally heat the 1,3-propanediol in the first feed pipeline 21, it is ensured that it enters the decolorizing column 10 in a gaseous form.

[0051] In the present utility model, the heater 40 can adopt any appropriate structural form as long as it can heat the 1,3-propanediol flowing through the first feed pipeline 21 to ensure that it enters the decolorizing column 10 in a gaseous form. Exemplarily, the heater 40 is an electric heater or a steam heater.

[0052] In some embodiments, the purification device further includes a condenser 50, a gas-liquid separator 60, and a vacuum pump 70. A heat exchange pipeline is provided in the condenser 50. The heat exchange pipeline is used to introduce a refrigerant to cool the material passing through the condenser 50. One end of the condenser 50 is provided with a material inlet 501, and the other end is provided with a material outlet 502. The material inlet 501 is communicated with the air outlet 102 of the decolorizing column 10 through a second feed pipeline 16. Correspondingly, for the convenience of control, a second control valve 161 is provided on the second feed pipeline 16 to control the on-off of the second feed pipeline 16; the gas-liquid separator 60 is used to perform gas-liquid separation on the material flowing out of the material outlet 502 of the condenser 50. Specifically, a fourth feed pipeline 51 is provided between the material outlet 502 of the condenser 50 and the feed inlet of the gas-liquid separator 60, and a fourth control valve 511 is provided on the fourth feed pipeline 51 to control the on-off of the fourth feed pipeline 51; the air extraction port of the vacuum pump 70 is communicated with the gas phase outlet of the gas-liquid separator 60 to form a vacuum environment in the gas-liquid separator 60. Specifically, the air extraction port of the vacuum pump 70 is communicated with the gas phase outlet of the gas-liquid separator 60 through an air extraction pipeline 71, and an air extraction valve 711 is provided on the air extraction pipeline 71.

[0053] In the present utility model, the condenser 50 is provided to cool the 1,3 - propanediol flowing out of the decolorization column 10 to make it liquefy. Then, the gas - liquid separator 60 is used to separate the gas - phase components contained in the material, and a relatively pure 1,3 - propanediol product is obtained. The vacuum pump 70 can form a vacuum environment in the gas - liquid separator 60, prompting the 1,3 - propanediol to continuously flow out of the decolorization column 10, flow through the condenser 50 and into the gas - liquid separator 60. Through the above - mentioned structural arrangement, the continuous purification operation of 1,3 - propanediol is ensured, so that the 1,3 - propanediol finished product can be continuously withdrawn from the liquid - phase outlet of the gas - liquid separator 60.

[0054] It should be noted that in the initial stage of the operation of the whole system, the 1,3 - propanediol to be purified has not been completely formed into a gas state, so it is not suitable to be directly introduced into the decolorization column 10; or, when the packing layer 11 in the decolorization column 10 needs to be replaced, the 1,3 - propanediol needs to be refluxed to the rectification column 20 to avoid waste of the material to be purified.

[0055] In some embodiments, the material inlet 501 and the top outlet 201 of the rectification column 20 are connected through a third feeding pipeline 24. It can be understood that for convenient control, a third control valve 241 is provided on the third feeding pipeline 24 to control the on - off of the third feeding pipeline 24; the liquid - phase outlet of the gas - liquid separator 60 is respectively connected to a reflux pipeline 61 with a reflux valve 611 and a second discharging pipeline 62 with a second discharging valve 621. The other end of the reflux pipeline 61 is connected to the upper reflux port 204 of the rectification column 20, and a reflux feeding pump 612 is provided on the reflux pipeline 61.

[0056] In the initial stage of the operation of the whole system, the material discharged from the top outlet 201 of the rectification column 20 enters the condenser 50 through the third feeding pipeline 24, and then through the liquid - phase outlet of the gas - liquid separator 60, it is refluxed to the upper reflux port 204 of the rectification column 20 through the reflux pipeline 61. When the gas - phase content measured by sampling at the top outlet 201 of the rectification column 20 is ≥99.95%, the third control valve 241 on the third feeding pipeline 24 is closed, and the first control valve 211 on the first feeding pipeline 21 is opened to introduce the gaseous 1,3 - propanediol into the decolorization column 10 for filtration treatment.

[0057] Furthermore, in the present utility model, in order to facilitate monitoring the flow rate, a flow meter 613 is provided on the reflux pipeline 61.

[0058] It should be noted that the 1,3 - propanediol purification device provided by the present utility model is applicable to 1,3 - propanediol prepared by any suitable method, including but not limited to the microbial fermentation method, and can also be 1,3 - propanediol that has experienced long - term storage, absorbed or generated a small amount of water and trace colorless and colored impurities.

[0059] After obtaining a fermentation broth containing 1,3 - propanediol by microbial fermentation, the fermentation broth is filtered by a ceramic membrane to remove cell protein, and then filtered by a nanofiltration membrane to remove impurities, evaporated and concentrated, cooled and filtered to remove salts, evaporated and concentrated again, and water is removed by a wiped - film evaporator to obtain crude 1,3 - propanediol. To improve the decolorization and purification effect and efficiency, the gas - phase purity of the crude 1,3 - propanediol to be treated should be ≥99.5%, the absorbance should be ≤0.8 L / (g·cm), and the transmittance should be ≥5%.

[0060] As Figure 1 shown is a purification device for 1,3 - propanediol provided by the present utility model. When using this purification device to purify the above - mentioned crude 1,3 - propanediol, the crude 1,3 - propanediol is transported into the rectifying column 20 through the feed inlet in the upper - middle part of the rectifying column 20 by a feed pump, and the feeding is stopped after reaching the liquid level of 1 / 3 - 1 / 2 of the rectifying column 20; open the third control valve 241, the fourth control valve 511, the reflux valve 611 and the air - extraction valve 711, close the first control valve 211, the second discharge valve 621, and the feed valves 171 and the second control valve 161 corresponding to the two decolorizing columns 10; start the reboiler 30, the condenser 50 and the vacuum pump 70 to perform total reflux of the rectifying column 20. After the whole purification system is stable, when the gas - phase content measured by sampling at the top of the rectifying column 20 is ≥99.9%, open the heater 40, the first control valve 211, and the feed valve 171 and the second control valve 161 corresponding to one of the decolorizing columns 10, and close the third control valve 241 to make the gaseous 1,3 - propanediol enter the decolorizing column 10 for decolorization and impurity removal. At this time, the system still maintains total reflux. After sampling and detecting that the product quality in the gas - liquid separator 60 is qualified, the crude 1,3 - propanediol continuously enters the rectifying column 20, slowly reduce the frequency of the reflux feed pump 612 to reduce the reflux amount of the rectifying column 20, open the second discharge valve 621, and output the qualified product to the outside through the second discharge pipeline 62.

[0061] After the above - mentioned decolorizing column 10 is saturated, close the second discharge valve 621, slowly increase the frequency of the reflux feed pump 612 to perform total reflux of the rectifying column 20, open the feed valve 171 and the second control valve 161 corresponding to the other decolorizing column 10, close the feed valve 171 and the second control valve 161 corresponding to the saturated decolorizing column 10, and perform the switching of the decolorizing column 10. Similarly, after sampling and detecting that the product quality in the gas - liquid separator 60 is qualified, the crude 1,3 - propanediol continuously enters the rectifying column 20, slowly reduce the frequency of the reflux feed pump 612 to reduce the reflux amount of the rectifying column 20, open the second discharge valve 621, and output the qualified product to the outside through the second discharge pipeline 62.

[0062] Example 2

[0063] The present utility model provides a purification method for 1,3 - propanediol. The purification method includes: heating the crude 1,3 - propanediol to convert it into a gas state, and contacting the gaseous 1,3 - propanediol with the packing activated carbon in a decolorization column for decolorization and purification;

[0064] Among them, the source and preparation of the crude 1,3 - propanediol are as follows: passing the 1,3 - propanediol fermentation broth through a ceramic membrane for primary membrane filtration to filter out bacterial cells, macromolecular proteins, etc.; passing the clear liquid of the ceramic membrane obtained by filtration through a nanofiltration membrane for secondary membrane filtration to remove some small - molecule bacterial proteins and some pigments, etc.; concentrating the nanofiltration clear liquid under reduced pressure at - 0.085 to - 0.1 MPa and 75 - 85 °C until the PDO content in the concentrated liquid is 600 - 700 g / L; slowly cooling the concentrated liquid with stirring, and after cooling to 10 - 25 °C, centrifuging to separate and remove insoluble salts to obtain the desalted concentrated liquid; concentrating the desalted concentrated liquid again under reduced pressure at - 0.085 to - 0.1 MPa and 75 - 85 °C until the PDO content in the concentrated liquid reaches 900 - 950 g / L; distilling off water from the concentrated liquid through a wiped - film evaporator, with the heat source provided by an oil - bath heating system, and separating to obtain the crude 1,3 - propanediol using the difference in boiling points. The gas - phase purity of the obtained crude 1,3 - propanediol is ≥99.5%, the absorbance is ≤0.8 L / (g·cm), and the transmittance is ≥5%.

[0065] In this example, the gas - phase purity of the crude 1,3 - propanediol prepared and used is 99.75%, the absorbance is 0.24 L / (g·cm), and the transmittance is 27%.

[0066] The decolorization and purification of the above - mentioned batch of crude 1,3 - propanediol is carried out as follows: rectifying the crude 1,3 - propanediol using a rectifying column, controlling the vacuum degree of the rectifying column to be 230 - 240 par, the top - tower temperature to be 85 - 90 °C, and the bottom - tower temperature to be 125 - 135 °C; when the gas - phase purity of 1,3 - propanediol detected by sampling at the top of the rectifying column is ≥99.95%, contacting the gaseous 1,3 - propanediol with the packing activated carbon in the decolorization column for decolorization and purification, and using the purification device for 1,3 - propanediol in Example 1 for decolorization and purification.

[0067] In this example, activated carbons with different performance parameters are screened (the particle size of the activated carbons is 12 - 40 mesh), and 2 kinds of activated carbons with good decolorization performance for 1,3 - propanediol are obtained. In addition to the above 2 kinds of activated carbons, 2 other kinds of activated carbons are selected for comparison. The specific data are shown in Table 1.

[0068] Table 1:

[0069]

[0070] According to the purification method provided by the present utility model, by heating the crude 1,3-propanediol to be purified into a gaseous state, and making it contact with the packing material capable of adsorbing impurities in 1,3-propanediol in a gaseous form, compared with the traditional liquid-phase decolorization, the purification method provided by the present utility model can more efficiently remove impurities in the crude 1,3-propanediol.

[0071] Based on the packing materials in each of the examples and comparative examples in Table 1, the crude 1,3-propanediol obtained from the same batch of microbial fermentation was decolorized and purified to obtain 1,3-propanediol products, and the test performance is shown in Table 2.

[0072] Table 2:

[0073] Filler type Gas phase purity / % Absorbance L / (g·cm) Transmittance / % High temperature discoloration condition Example 1 99.99 0 71 No discoloration Example 2 99.97 0.06 51 No discoloration Comparison 1 99.96 0.18 38 Turned yellow Control Example 2 99.97 0.10 42 Turned yellow

[0074] The inventors of the present application found that by using the activated carbon in Example 1 and Example 2 and combining with the purification method of the present utility model, not only can the impurities in 1,3-propanediol be efficiently removed, but also the quality of the 1,3-propanediol finished product can be significantly improved.

[0075] In the above examples and comparative examples, for the purified 1,3-propanediol, the following methods were used to detect various performances.

[0076] 1. Gas phase purity

[0077] The test instrument was a gas chromatograph, the chromatographic column used was a DB-624 capillary column, and the column length / column inner diameter / liquid film thickness was 30m×0.32mm×1.80μm; the detector was a flame ionization detector (FID); the chromatographic oven temperature was: the initial temperature was 80°C, held for 1 minute, heated to 250°C at a rate of 10°C / min, and held for 12 minutes; the injection port temperature was 250°C; the detector temperature was 300°C; the carrier gas was nitrogen, the split ratio was 100:1, the injection volume was 1μL, and the flow rate was 30ml / min.

[0078] 2. Absorbance

[0079] Using a 10mm cuvette, at a wavelength of 250nm, with pure water as the blank, the absorbance was measured using a UV spectrophotometer.

[0080] 3. Transmittance

[0081] Using a 10mm cuvette, at a wavelength of 430nm, with pure water as the blank, the transmittance was measured using a UV spectrophotometer.

[0082] 4. High temperature discoloration situation

[0083] Take 20 - 30 g of 1,3 - propanediol sample and put it into a round - bottom flask. Then place the round - bottom flask in an oil - bath environment at 200 °C and maintain for 5 h, and observe the color of the 1,3 - propanediol sample.

[0084] After undergoing the above high - temperature treatment, if there is no color change, it indicates that the product quality of 1,3 - propanediol is good, and it has good effects when used in polymer materials subsequently, and has stronger market competitiveness.

[0085] The preferred embodiments of the present utility model have been described in detail above in conjunction with the accompanying drawings. However, the present utility model is not limited thereto. Within the scope of the technical concept of the present utility model, various simple modifications can be made to the technical solutions of the present utility model. To avoid unnecessary repetition, the present utility model will not separately describe various possible combinations. But these simple modifications and combinations should also be regarded as the content disclosed by the present utility model and all fall within the protection scope of the present utility model.

Claims

1. A purification device for 1,3-propanediol, characterized in that, It includes a heating unit and a decolorizing column (10). The heating unit is arranged at the feeding end of the decolorizing column (10) and can heat the 1,3-propanediol entering the decolorizing column (10) into a gaseous state. A packing layer (11) is arranged in the decolorizing column (10) for filtering the gaseous 1,3-propanediol.

2. The purification device of 1,3-propanediol according to claim 1, characterized in that, The decolorizing column (10) extends in the vertical direction and has an air inlet (101) at the lower end of the decolorizing column (10) and an air outlet (102) at the upper end of the decolorizing column (10). The gaseous 1,3-propanediol enters from the air inlet (101) and flows out from the air outlet (102); A liquid collecting weir (12) is arranged on the inner wall of the decolorizing column (10) below the packing layer (11). The liquid collecting weir (12) extends along the circumferential direction of the inner wall of the decolorizing column (10). A liquid discharge port (103) capable of communicating with the liquid collecting weir (12) is arranged on the decolorizing column (10).

3. The purification device for 1,3-propanediol according to claim 2, characterized in that, A liquid discharge pipe (13) extending into the liquid collecting weir (12) is connected to the liquid discharge port (103). A liquid suction pump (131) is arranged on the liquid discharge pipe (13) for sucking out the liquid-phase material in the liquid collecting weir (12).

4. The purification device for 1,3-propanediol according to claim 1, wherein A plurality of packing layers (11) are arranged. The plurality of packing layers (11) are arranged in sequence in the decolorizing column (10) along the flow direction of the gaseous 1,3-propanediol.

5. The purification device for 1,3-propanediol according to claim 4, characterized in that, A distributor (14) is arranged on the feeding side of the packing layer (11) in the decolorizing column (10). The distributor (14) is used for dispersing the gaseous 1,3-propanediol.

6. The purification device for 1,3-propanediol according to claim 5, wherein A dust filtering layer (15) is arranged on the discharging side of the packing layer (11) in the decolorizing column (10). The dust filtering layer (15) is used for intercepting and filtering the packing powder.

7. The purification device for 1,3-propanediol according to claim 1, characterized in that, A heat preservation structure is arranged outside the decolorizing column (10).

8. The purification device for 1,3-propanediol according to any one of claims 1-7, characterized in that, The heating unit includes a rectifying column (20) with a reboiler (30). The top outlet (201) of the rectifying column (20) is connected to the air inlet (101) of the decolorizing column (10) through a first feeding pipeline (21). The bottom outlet (202) of the rectifying column (20) is connected to a first discharging pipeline (22) with a first discharging valve (221). A branch pipeline (23) is connected to the first discharging pipeline (22) between the first discharging valve (221) and the bottom outlet (202). The other end of the branch pipeline (23) is connected to the inlet of the reboiler (30). The outlet of the reboiler (30) is connected to the lower reflux port (203) of the rectifying column (20).

9. The purification device for 1,3-propanediol according to claim 8, characterized in that, A plurality of decolorizing columns (10) are arranged in parallel. The air inlets (101) of the plurality of decolorizing columns (10) are respectively connected to the top outlet (201) of the rectifying column (20) through the first feeding pipeline (21).

10. The purification device for 1,3-propanediol according to claim 9, wherein The heating unit further includes a heater (40) arranged on the first feeding pipeline (21). The heater (40) is used for heating the 1,3-propanediol flowing through the first feeding pipeline (21).

11. The purification device for 1,3-propanediol according to claim 8, wherein, The purification device further includes: A condenser (50), in which a heat exchange pipeline is provided. The heat exchange pipeline is used to introduce a refrigerant to cool the material passing through the condenser (50). One end of the condenser (50) is provided with a material inlet (501), and the other end is provided with a material outlet (502). The material inlet (501) is communicated with the gas outlet (102) of the decolorizing column (10) through a second feeding pipeline (16); A gas-liquid separator (60), which is used to separate the gas and liquid of the material flowing out from the material outlet (502) of the condenser (50); and A vacuum pump (70), the air suction port of which is communicated with the gas phase outlet of the gas-liquid separator (60), and is used to form a vacuum environment in the gas-liquid separator (60).

12. The purification device for 1,3-propanediol according to claim 11, characterized in that, The material inlet (501) is communicated with the top outlet (201) of the rectifying column (20) through a third feeding pipeline (24); The liquid phase outlet of the gas-liquid separator (60) is respectively connected to a reflux pipeline (61) with a reflux valve (611) and a second discharging pipeline (62) with a second discharging valve (621). The other end of the reflux pipeline (61) is connected to the upper reflux port (204) of the rectifying column (20), and a reflux feeding pump (612) is arranged on the reflux pipeline (61).

13. The purification device for 1,3-propanediol according to claim 12, characterized in that, A flowmeter (613) is arranged on the reflux pipeline (61).

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