Method and device for online energy conservation and scale prevention of 1, 4-butylene glycol vacuum system

Abstract

The invention provides a 1, 4-butylene glycol vacuum system on-line energy-saving anti-scaling method and device, and the method comprises the following steps: decoloring a 1, 4-butylene glycol crude product solution, inputting the decolored 1, 4-butylene glycol crude product solution into a desolventizing tower, condensing and separating a material extracted from a side line of the desolventizing tower to obtain a first tail gas and a second material, condensing and separating the tower top extract to obtain second tail gas and a regenerated solvent; inputting the second material into a product tower, condensing and separating a material extracted from a side line of the product tower to obtain third tail gas and a high-purity 1, 4-butenediol product, and condensing and separating a material extracted from a tower top to obtain fourth tail gas; the first tail gas, the second tail gas, the third tail gas and the fourth tail gas are input into an absorption tower to be in contact with a poor absorbent in the absorption tower, fifth tail gas extracted from the tower top of the absorption tower is input into a vacuum system, a rich absorbent extracted from a tower kettle of the absorption tower is input into a desolventizing tower, and at least part of a regenerated solvent is conveyed to the absorption tower. The method can be continuously operated for more than or equal to 200h to obtain a 1, 4-butenediol product with the purity of more than or equal to 98%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical synthesis, in particular to a method and device for online energy-saving and scale prevention of 1,4-butenediol vacuum system. BACKGROUND

[0002] 1,4-butenediol (BED, also known as 2-butene-1,4-diol) is a monomer for synthesizing polyester and polyether, and is used as a crosslinking agent or modifier for coatings, polymer materials and textiles. It is also an intermediate for fine chemicals such as vitamin B6, endosulfan (herbicide), 2,5-dihydrofuran, etc. The preparation of 1,4-butenediol mainly includes 1,4-butynediol method, butadiene acetoxylation method and 1,4-dichloro-2-butene method. Among them, the 1,4-butynediol semi-hydrogenation method becomes the mainstream process because of easy availability of raw materials and low cost. However, the crude product obtained by this method has high colority, which needs to be decolorized to avoid affecting the product quality and the service life of the downstream reaction catalyst. More importantly, 1,4-butenediol is prone to polymerization during the rectification and purification process (especially in long-period operation of 150-200 hours), which leads to blockage of the vacuum system and frequent shutdown for maintenance.

[0003] The existing technologies have not effectively solved this polymerization problem: for example, patent CN118666645A discloses a 1,4-butenediol purification and refining method and system, which adopts a four-tower combined system including a water recovery tower, a dehydration tower, a light removal tower and a refining tower. Through distillation, dehydration, light removal and refining steps, 1,4-butenediol aqueous solution is treated under micro-positive pressure and negative pressure conditions respectively to realize high-purity purification, and the condensation heat is recovered through thermal coupling to reduce energy consumption. Patent CN106397129A discloses a system and process for continuous production of 1,4-butenediol and 1,4-butanediol by hydrogenation of 1,4-butynediol. Through a continuous production system including a decolorization reaction system, a semi-hydrogenation reaction system, a butenediol rectification system and a butanediol rectification system, two semi-hydrogenation reactors are connected in series, hydrogen is recycled, reaction temperature and pressure are controlled, and efficient production of butenediol and butanediol is realized. In addition, high-pressure reaction is carried out in the full hydrogenation reaction system to improve conversion rate and selectivity. Moreover, the above two patents involve a large number of rectification towers, which have the problems of large equipment investment and high energy consumption. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application discloses a method and device for online energy-saving and scale prevention of 1,4-butenediol vacuum system, which solves the problem of vacuum pump blockage in the rectification and purification process of 1,4-butenediol in the prior art, effectively reduces energy consumption and equipment investment, and improves economic benefits.

[0005] To achieve the above technical objectives, this invention proposes an online energy-saving and scale-preventing method for a 1,4-butenediol vacuum system, which includes the following steps: (1) The crude product solution of 1,4-butenediol is fed into a decolorization tower filled with adsorbent and the first material is obtained after decolorization treatment; (2) The first material is fed into the solvent removal tower to remove the solvent. The material taken from the side line of the solvent removal tower is condensed and separated to obtain the first tail gas and the second material in liquid phase. The material taken from the top of the tower is condensed and separated to obtain the second tail gas and the regenerated solvent in liquid phase. The first heavy component is taken from the bottom of the tower. (3) The second material is fed into the product tower. The material taken from the side line of the product tower is condensed and separated to obtain the third tail gas and liquid phase high-purity 1,4-butenediol product. The material taken from the top of the tower is condensed and separated to obtain the fourth tail gas and liquid phase light component material. The second heavy component is taken from the bottom of the tower. (4) The first tail gas, the second tail gas, the third tail gas and the fourth tail gas are fed into the absorption tower and contacted with the lean absorbent in the absorption tower. The fifth tail gas obtained after the top product of the absorption tower is condensed and separated is fed into the vacuum system. The rich absorbent collected from the bottom of the absorption tower is fed into the desolventizing tower, and at least a portion of the regenerated solvent is transported to the absorption tower as a lean solvent.

[0006] 1,4-Butenediol undergoes free radical reactions during reaction and distillation to form chain polymers. Furthermore, 4-hydroxybutyraldehyde is a byproduct of the 1,4-butenediol preparation process. 4-Hydroxybutyraldehyde readily undergoes oxidation and condensation reactions to form red substances, or dehydrates to form butenal, which polymerizes to form a dimer, or dehydrates and cyclizes under high temperature and high vacuum conditions to form 2,5-dihydrofuran, which further polymerizes to form high molecular weight compounds. Through extensive experimentation, the researchers of this invention discovered that the exhaust gas from the distillation and purification of 1,4-butenediol, when input into the vacuum system (including the vacuum pump), may generate the aforementioned high molecular weight compounds. These compounds accumulate in the vacuum pump's piping in tar-like or powdery form, ultimately causing blockages in the vacuum pump.

[0007] The above technical solution uses only four functional towers to achieve decolorization, purification, and deep treatment of the crude 1,4-butenediol product solution, efficiently and with low energy consumption, solving the problem of vacuum pump blockage in the existing 1,4-butenediol refining process: The above technical solution uses an adsorption decolorization tower to remove colored impurities inherent in 1,4-butynediol and colored impurities generated during hydrogenation, resulting in a 1,4-butynediol product with lower color and higher purity; through a solvent removal tower and a product tower, the solvent, light component impurities (including 1,4-butenediol), and heavy component impurities (high-boiling substances) in the first material are gradually removed to obtain high-purity 1,4-butenediol. In addition, the above technical solution uses an absorption tower to further absorb compounds such as 1,4-butanediol and 1,4-butenediol in the tail gas generated during the operation of the desolventizing tower and product tower. This effectively reduces the polymerization and accumulation of 1,4-butenediol and byproducts in the vacuum pump pipeline, reduces the probability of vacuum pump pipeline blockage, reduces the frequency of shutdown and maintenance, and promotes the stable and continuous operation of the 1,4-butenediol refining process.

[0008] It should be noted that in this invention, lean absorbent refers to absorbent that has not yet undergone absorption or has completed regeneration, which has released solute and has strong absorption capacity; rich absorbent refers to absorbent that has completed absorption, which has absorbed a large amount of solute or is approaching saturation.

[0009] In the above technical solution: the second material includes 1,4-butenediol and a small amount of light component impurities (such as butanediol) and a small amount of heavy component impurities (such as butynediol). The first heavy component mainly includes unhydrogenated butynediol and hydrogenated polymers. The light component mainly includes butanediol. In an optional example of the present invention, the first heavy component and the light component may be subjected to incineration.

[0010] Optionally, the liquid material obtained after condensation and separation of the top product of the absorption tower is returned to the top of the absorption tower.

[0011] Furthermore, the first material and the material collected from the side stream of the desolventizing tower are coupled through a heat exchanger to condense and separate the material collected from the side stream of the desolventizing tower, thereby recovering and utilizing the heat in the material collected from the side stream of the desolventizing tower for preheating the first material, thereby improving the removal efficiency of the desolventizing tower and reducing its energy consumption.

[0012] Furthermore, the rich absorbent collected from the bottom of the absorption tower and the material collected from the top of the product tower are coupled through a heat exchanger to condense and separate the material collected from the top of the product tower, thereby recovering and utilizing the heat in the material collected from the top of the product tower for preheating the rich absorbent. This portion of the rich absorbent will be fed into the desolventizing tower, thus improving the removal efficiency of the desolventizing tower and reducing its energy consumption.

[0013] Furthermore, a demister is installed inside the top of the absorption tower to prevent gas from carrying liquid droplets into the tail gas at the top of the absorption tower.

[0014] It should be noted that the present invention does not limit the specific structure of the adsorption tower. A fixed-bed adsorption tower can be selected. Those skilled in the art can select an appropriate adsorbent according to the working conditions. All technical solutions formed therefrom are within the protection scope of the present invention.

[0015] Further, the content of 1,4-butenediol in the crude 1,4-butenediol product solution is 20wt% to 60wt%. In an optional example of the present invention, the content of 1,4-butenediol in the crude 1,4-butenediol product solution is 30wt% to 50wt%.

[0016] Furthermore, the crude 1,4-butenediol product solution is prepared by the 1,4-butynediol method or the butadiene acetylation method.

[0017] In this invention, the lean absorbent and the solvent contained in the crude 1,4-butenediol product solution are the same compound. Furthermore, the solvent in the crude 1,4-butenediol product solution is selected from at least one of alcohols, ethers, and amides with a boiling point of 100-205°C, thereby promoting efficient separation of the solvent from butanediol and butenediol. Furthermore, the alcohol includes high-boiling-point monohydric alcohols and dihydric alcohols, preferably isobutanol, n-butanol, n-pentanol, n-hexanol, 2-hexanol, cyclohexanol, benzyl alcohol, n-octanol, isooctanol, ethylene glycol, 1,2-propanediol, and 1,2-butanediol, more preferably ethylene glycol and 1,2-propanediol; further still, the ether includes at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether, preferably ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol diethyl ether; further still, the amide includes at least one of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, and N,N-diethylacetamide, preferably N,N-dimethylformamide.

[0018] Furthermore, the theoretical number of plates in the solvent removal tower is 40 to 50, thereby reducing energy consumption and equipment costs while ensuring separation effect; in an optional example of the present invention, the theoretical number of plates in the solvent removal tower is 43 to 47.

[0019] Furthermore, the first material is fed into the 10th to 15th trays to optimize the material distribution within the tower and improve separation efficiency.

[0020] Furthermore, the side stream sampling position of the solvent removal column is 15 to 25 trays, thereby improving the purity and yield of the target product; in an optional example of the present invention, the side stream sampling position of the solvent removal column is 18 to 22 trays.

[0021] Furthermore, the top temperature of the desolventizing column is 25~100℃, the side stream temperature is 115~135℃, the bottom temperature is 130~145℃, the operating pressure is 0.2~5kPaA, preferably 0.5~2kPaA, and the reflux ratio is 0.5~10. This achieves efficient separation while avoiding thermal decomposition of the material, lowering the system boiling point, reducing energy consumption, and optimizing operational economy. In an optional example of the present invention, the reflux ratio of the desolventizing column is 1~2.

[0022] Furthermore, the theoretical number of trays in the product tower is 35 to 45, preferably 38 to 42, thereby balancing equipment investment and operating energy consumption while achieving efficient separation.

[0023] Furthermore, the second material is fed into the 10th to 15th trays to optimize the gas-liquid distribution within the tower and improve separation efficiency.

[0024] Furthermore, the side sampling points of the product tower are 30 to 40 trays, thereby improving the purity of the target product and the overall product yield of the process.

[0025] Furthermore, the product column has a top temperature of 50~135℃, a side stream temperature of 125~135℃, a bottom temperature of 128~140℃, an operating pressure of 0.2~5kPaA, preferably 0.5~2kPaA, and a reflux ratio of 0.5~10, preferably 1.5~2.5. By optimizing the temperature gradients at the top, side stream, and bottom of the column, and by synergistically controlling the operating pressure and reflux ratio, efficient separation is achieved, product purity is improved, and energy consumption is reduced.

[0026] Furthermore, the temperature at the top of the absorption tower is 0~20℃, the temperature at the bottom of the tower is 5~35℃, and the operating pressure is 0.2~5kPaA, preferably 0.5~2kPaA, in order to effectively absorb the target product in the exhaust gas, prevent it from polymerizing and clogging in the vacuum pump, and ensure the stable operation of the vacuum system.

[0027] Furthermore, the mass concentration of 1,4-butenediol in the rich absorbent is 10% to 40%, which is beneficial to improve the absorption efficiency while reducing the energy consumption of the subsequent separation process. In an optional example of the present invention, the mass concentration of 1,4-butenediol in the rich absorbent is 20% to 30%.

[0028] Furthermore, the adsorbent is a macroporous adsorption resin or activated carbon.

[0029] Furthermore, the specific surface area of ​​the activated carbon is 600~1200 m². 2 / g; bulk density is 0.4~0.7g / cm³ 3 This provides sufficient active sites and ensures good bed permeability within the adsorption tower, thereby efficiently removing pigments from the 1,4-butenediol solution, extending the service life, and reducing regeneration frequency and operating costs. In an optional example of the present invention, the specific surface area of ​​the activated carbon is 800~1000 m². 2 / g. In an optional example of the invention, the bulk density is 0.5~0.6 g / cm³. 3 .

[0030] Furthermore, the decolorization tower operates at a temperature of 60-90°C, an operating pressure of 0.1-0.3 MPaG, and a volumetric hourly space velocity of 0.5-2 h⁻¹. -1 This provides suitable decolorization conditions, ensuring the adsorbent maintains high activity and improving decolorization efficiency. In an optional example of the invention, the operating temperature of the decolorization tower is 70-80°C. In an optional example of the invention, the operating pressure of the decolorization tower is 0.2-0.3 MPaG. In an optional example of the invention, the volume hourly space velocity of the decolorization tower is 1-1.5 h⁻¹. -1 .

[0031] Furthermore, the second heavy component is fed into the desolventizing tower to fully recover the 1,4-butenediol contained in the second heavy component and improve the process yield.

[0032] Furthermore, the vacuum system includes a vacuum pump, and the exhaust gas from the top of the absorption tower is cryogenically treated before being fed into the vacuum pump.

[0033] On the other hand, this invention proposes an online energy-saving and scale-preventing device for a 1,4-butenediol vacuum system, which includes a decolorization tower, a solvent removal tower, a product tower, an absorption tower, and a vacuum system; wherein: The feed inlet of the decolorization tower is used to input the crude 1,4-butenediol product solution to be purified, and the bottom of the decolorization tower is connected to the feed inlet of the desolventizing tower. The side outlet of the solvent removal tower is connected to the first condenser, and the liquid phase outlet of the first condenser is connected to the feed inlet of the product tower; the top of the solvent removal tower is connected to the second condenser, and the liquid phase outlet of the second condenser is used to collect the regenerated solvent. The side outlet of the product tower is connected to a third condenser, and the liquid phase outlet of the third condenser produces high-purity 1,4-butenediol product; the top of the product tower is connected to a fourth condenser, and the liquid phase outlet of the fourth condenser is used to produce light component materials. The gas phase outlets of the first condenser, the second condenser, the third condenser, and the fourth condenser are connected to the first feed inlet of the absorption tower. The top of the absorption tower is connected to a fifth condenser, and the gas phase outlet of the fifth condenser is connected to the vacuum system. The bottom of the absorption tower is connected to the feed inlet of the solvent removal tower. The liquid phase outlet of the second condenser is connected to the second feed inlet of the absorption tower via a first branch, thereby inputting a portion of the regenerated solvent into the absorption tower as a lean solvent.

[0034] Optionally, the rich absorbent output from the bottom of the absorption tower is connected to the inlet of the desolventizing tower after heat exchange in the fourth condenser, so as to recover the heat in the rich absorbent output from the bottom of the absorption tower.

[0035] Optionally, the bottom of the decolorization tower is connected to the desolvation tower via the refrigerant channel of the first condenser.

[0036] Optionally, the bottom of the absorption tower is connected to the desolvation tower via the refrigerant channel of the fourth condenser.

[0037] Optionally, the bottom outlet of the product column is connected to the feed inlet of the desolventizing column.

[0038] Optionally, the vacuum system includes a cryostat and a vacuum pump; the gas phase outlet of the fifth condenser is connected to the cryostat, and the gas phase outlet of the cryostat is connected to the vacuum pump.

[0039] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention improves the color and purity of 1,4-butynediol by using a decolorization tower, a desolventization tower, and a product tower, and gradually removes solvents, light component impurities, and heavy component impurities from the first material to obtain high-purity 1,4-butenediol. Simultaneously, an absorption tower is used to further absorb and recover 1,4-butenediol from the tail gas generated during the operation of the desolventization tower and the product tower. This effectively reduces the polymerization and accumulation of 1,4-butenediol and byproducts in the vacuum pump pipeline, lowering the probability of vacuum pump pipeline blockage, reducing the frequency of shutdowns and maintenance, and promoting stable and continuous process operation. This invention reduces the number of distillation towers by using side-stream sampling from the desolventization tower and the product tower, which not only reduces equipment investment and floor space but also significantly reduces energy consumption, lowering production costs while ensuring the quality of 1,4-butenediol. The method and apparatus of this invention can operate continuously for ≥200 hours, obtaining 1,4-butenediol products with a purity ≥98%. Attached Figure Description

[0040] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This diagram illustrates a structural embodiment of the online energy-saving and scale-preventing device for the 1,4-butenediol vacuum system of the present invention.

[0041] Figure 2 This invention presents another structural diagram of the online energy-saving and scale-preventing device for the 1,4-butenediol vacuum system.

[0042] The above figures include the following reference numerals: 1-Decolorization tower, 2-Solvent removal tower, 3-Product tower, 4-Absorption tower, 5-Vacuum system, 51-Vacuum pump, 61-First condenser, 62-Second condenser, 63-Third condenser, 64-Fourth condenser, 65-Fifth condenser, 66-Cryogenic cooler, 71-Buffer tank, 72-Solvent receiving tank, 73-Crude product receiving tank, 74-Light component receiving tank, 75-Product tank, 76-Cryogenic liquid storage tank. Detailed Implementation

[0043] To facilitate understanding of the present invention, a more comprehensive description will be provided below, along with preferred embodiments. However, it should be understood that these embodiments are merely for more detailed explanation and should not be construed as limiting the invention in any way, i.e., not intended to limit the scope of protection of the invention.

[0044] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0045] Furthermore, it should be noted that although the various steps of the preparation method of the present invention are described in a specific order in the description of the present invention, these orders are not restrictive. Without departing from the basic principles of the present invention, those skilled in the art can perform the steps in different orders.

[0046] Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "multiple" or "at least one" means two or more.

[0047] All numerical designations, such as temperature, pressure, flow rate, and range, are approximate values. It should be understood that, while not always explicitly stated, all numerical designations are preceded by the term "approximately." It should also be understood that, while not always explicitly stated, the reagents described herein are merely examples, and their equivalents are known in the art.

[0048] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0049] In this embodiment of the invention, the method for determining colorimetry refers to GB / T605-2006. The method for measuring colorimetry is as follows: an appropriate amount of sample solution is measured at a wavelength of 430 nm using a spectrophotometer, and the colorimetry is compared with that of a platinum-cobalt standard solution to calculate the colorimetry of the sample. Hazen units are defined as the colorimetry of a platinum-cobalt solution containing 1 mg of platinum in the form of potassium chloroplatinate (H₂PtCl₆) and 2 mg of cobalt chloride hexahydrate (CoCl₂·6H₂O) per liter.

[0050] The composition of the crude 1,4-butenediol product solutions to be purified in Examples 1-6 is shown in Table 1, wherein the solvent includes at least one of alcohol, ether, and amide. The crude 1,4-butenediol product solutions in Examples 1-6 are obtained by selective hydrogenation of 1,4-butynediol under the action of catalysts such as Pd / C or Pd / CaCO3. The hydrogenation byproduct 4-hydroxybutyraldehyde is distilled off with the solvent in the desolventizing tower 2 and reused with the solvent in the hydrogenation reaction. 4-hydroxybutyraldehyde is reduced to 1,4-butanediol, which is collected as a light component in the product tower 3. Therefore, 4-hydroxybutyraldehyde will not accumulate in the system.

[0051] The 1,4-butenediol in Example 7 was obtained by butadiene acetoxylation, and then 1,4-butenediol was extracted with ethylene glycol diethyl ether to obtain a crude 1,4-butenediol product solution to be purified, the composition of which is shown in Table 2.

[0052] Table 1

[0053] Table 2

[0054] Figure 1 This invention illustrates an optional device for an online energy-saving and scale-preventing 1,4-butenediol vacuum system 5. The device includes a decolorization tower 1, a solvent removal tower 2, a product tower 3, an absorption tower 4, and a vacuum system 5. Specifically: the inlet of the decolorization tower 1 is used to input the crude 1,4-butenediol product solution to be purified; the bottom of the decolorization tower 1 is connected to the inlet of the solvent removal tower 2; the side outlet of the solvent removal tower 2 is connected to a first condenser 61, and the liquid phase outlet of the first condenser 61 is connected to the inlet of the product tower 3; the top of the solvent removal tower is connected to a second condenser 62, and the liquid phase outlet of the second condenser 62 is used to collect the regenerated solvent; the side outlet of the product tower 3 is connected to a third condenser 63, and the liquid phase outlet of the third condenser 63 is used to collect the regenerated solvent. The liquid phase outlet of the product tower 3 produces high-purity 1,4-butenediol; the top of the product tower 3 is connected to the fourth condenser 64, and the liquid phase outlet of the fourth condenser 64 is used to produce light component materials; the gas phase outlets of the first condenser 61, the second condenser 62, the third condenser 63, and the fourth condenser 64 are connected to the first feed inlet of the absorption tower 4; the top of the absorption tower 4 is connected to the fifth condenser 65, and the gas phase outlet of the fifth condenser 65 is connected to the vacuum system 5; the bottom of the absorption tower 4 is connected to the feed inlet of the solvent removal tower 2, and the liquid phase outlet of the second condenser 62 is connected to the second feed inlet of the absorption tower 4 via the first branch, thereby inputting a portion of regenerated solvent into the absorption tower 4 as lean solvent.

[0055] Optionally, such as Figure 2As shown, the rich absorbent output from the bottom of absorber 4 is connected to the inlet of desolventizing tower 2 after heat exchange in the fourth condenser 64, in order to recover the heat in the rich absorbent output from the bottom of absorber 4.

[0056] Optionally, the bottom of the decolorization tower 1 is connected to the desolvation tower 2 via the refrigerant channel of the first condenser 61.

[0057] Optionally, the bottom of the absorption tower 4 is connected to the desolvation tower 2 via the refrigerant channel of the fourth condenser 64.

[0058] Optionally, the bottom outlet of product column 3 is connected to the feed inlet of desolventizing column 2.

[0059] Optionally, the vacuum system 5 includes a cryostat 66 and a vacuum pump 51; the gas phase outlet of the fifth condenser 65 is connected to the cryostat 66, and the gas phase outlet of the cryostat 66 is connected to the vacuum pump 51.

[0060] It should be noted that those skilled in the art may optionally install a buffer tank 71 on the pipeline connecting the decolorization tower 1 and the solvent removal tower 2 to improve the stability of process operation; optionally, a solvent receiving tank 72 for collecting solvent may be installed; optionally, a crude product receiving tank 73 for collecting crude product may be installed; optionally, a light component receiving tank 74 for collecting light components may be installed; optionally, a product tank 75 for collecting products may be installed. A cryogenic liquid storage tank 76 for collecting condensate from the cryogenic cooler 66 may also be installed. Furthermore, to improve the material transport rate during the process, a fan or circulating pump may be installed at a suitable location in the online energy-saving and anti-scaling device of the 1,4-butenediol vacuum system 5 of this invention, and the resulting technical solution is within the scope of protection of this invention. Additionally, those skilled in the art may optionally install a reboiler at a suitable location in the tower reboiler of the tower equipment. Example

[0061] A method for online energy saving and scale prevention in a 1,4-butenediol vacuum system includes the following steps: (1) A solution of 1,4-butenediol in ethylene glycol (boiling point 197℃ / 0.1MPaA, 73℃ / 1 PaA) after selective hydrogenation of 1,4-butynediol is fed into decolorization tower 1. Decolorization tower 1 is filled with activated carbon as an adsorbent, and the specific surface area of ​​the activated carbon is 900 m². 2 / g, bulk density 0.5 g / cm³ 3 The decolorization tower 1 operates at a temperature of 75℃, an operating pressure of 0.2MPaG, and a bed pressure drop of 50kPa, and outputs the first material.

[0062] (2) The first material is fed into the first condenser 61 and exchanges heat with the second material collected from the side stream of the desolventizing tower 2. Then it is fed into the desolventizing tower 2 for desolventizing. The temperature at the top of the tower is 95~100℃, the temperature at the side stream is 130~135℃, the temperature at the bottom of the tower is 135~140℃, and the operating pressure is 0.5~2 kPaA. After the top material is condensed, the solvent in the liquid phase is recovered and the second tail gas is collected. After the side stream product is condensed and separated, the first tail gas and the second material in the liquid phase are obtained, namely the crude product of 1,4-butenediol. The first heavy component is collected from the bottom of the tower and fed into the waste liquid incinerator.

[0063] (3) The second material is fed into product tower 3 to remove light components and second heavy components. The temperature at the top of the tower is 127~132℃, the temperature at the side stream is 128~133℃, the temperature at the bottom of the tower is 130~135℃, and the operating pressure is 0.5~2kPaA. After the top of the tower is condensed, the fourth tail gas and liquid light component materials (residual solvent, 4-hydroxybutyraldehyde, 1,4-butanediol, etc.) are obtained. After the product in the tower is condensed, the third tail gas and high-purity 1,4-butenediol are obtained. The second heavy component is collected from the bottom of the tower and fed into desolventizing tower 2 to recover 1,4-butenediol.

[0064] (4) The first, second, third, and fourth tail gases are fed into the first inlet at the bottom of the absorption tower 4 to absorb the uncondensed 1,4-butenediol contained therein, forming a rich solvent in the absorption tower 4; the absorbent is ethylene glycol, the tower bottom temperature is 25~30℃, and the operating pressure is 0.5~2kPaA; when the 1,4-butenediol content in the solution of the absorption tower 4 reaches 20%, the rich absorbent in the absorption tower 4 is fed into the fourth condenser 64 to exchange heat with the material collected from the top of the product tower 3, and then fed into the desolventizing tower 2, while the regenerated absorbent is replenished through the second inlet of the absorption tower 4. The results of this embodiment are shown in Table 12.

[0065] To further verify the superiority of the process conditions of this invention, the R&D team used Aspen Plus software to simulate the operation of the desolventizing tower 2, product tower 3, and absorption tower 4 in this embodiment. The simulation results are shown in Table 3.

[0066] Table 3

[0067] Example 2 A method for online energy saving and scale prevention in a 1,4-butenediol vacuum system includes the following steps: (1) The 1,4-butenediol solution of 1,4-butenediol after selective hydrogenation by the 1,4-butynediol method, in 1,2-propanediol (boiling point 187℃ / 0.1MPaA, 88℃ / 2 kPaA) is fed into decolorization tower 1. Decolorization tower 1 is filled with activated carbon as an adsorbent, and the specific surface area of ​​the activated carbon is 1200 m². 2 / g, bulk density 0.4 g / cm³ 3 The decolorization tower 1 operates at a temperature of 75℃, an operating pressure of 0.3 MPaG, and a bed pressure drop of 50 kPa; the output is the first material.

[0068] (2) The first material is fed into the first condenser 61 to exchange heat with the second material collected from the side stream of the desolventizing tower 2, and then fed into the desolventizing tower 2 for desolventizing. The top temperature of the tower is 85~90℃, the side stream temperature is 125~130℃, the bottom temperature of the tower is 130~135℃, and the operating pressure is 0.5~2 kPaA. After the top material is condensed, the solvent in the liquid phase is recovered and the second tail gas is collected. After the side stream product is condensed and separated, the first tail gas and the second liquid material are obtained, namely the crude product of 1,4-butenediol. The first heavy component is collected from the bottom of the tower and fed into the waste liquid incinerator.

[0069] (3) The second material is fed into product tower 3 to remove light components and second heavy components. The temperature at the top of the tower is 115~120℃, the temperature at the side stream is 129~134℃, the temperature at the bottom of the tower is 130~135℃, and the operating pressure is 0.5~2kPaA. After the top of the tower is condensed, the fourth tail gas and liquid light component material (residual solvent, 4-hydroxybutyraldehyde, 1,4-butanediol, etc.) are obtained. After the product in the tower is condensed, the third tail gas and high-purity 1,4-butenediol are obtained. The second heavy component is collected from the bottom of the tower and fed into desolventizing tower 2 to recover 1,4-butenediol.

[0070] (4) The first, second, third, and fourth tail gases are fed into the first inlet at the bottom of the absorption tower 4 to absorb the uncondensed 1,4-butenediol contained therein, forming a rich solvent in the absorption tower 4; the absorbent is 1,2-propanediol, the tower bottom temperature is 10~15℃, and the operating pressure is 0.5~2kPaA; when the 1,4-butenediol content in the solution of the absorption tower 4 reaches 20%, the rich absorbent in the absorption tower 4 is fed into the fourth condenser 64 to exchange heat with the material collected from the top of the product tower 3, and then fed into the desolventizing tower 2, while the regenerated absorbent is replenished through the second inlet of the absorption tower 4. The results of this embodiment are shown in Table 12.

[0071] To further verify the superiority of the process conditions of this invention, the R&D team used Aspen Plus software to simulate the operation of the desolventizing tower 2, product tower 3, and absorption tower 4 in this embodiment. The simulation results are shown in Table 4.

[0072] Table 4

[0073] Example 3 A method for online energy saving and scale prevention in a 1,4-butenediol vacuum system includes the following steps: (1) A solution of 1,4-butenediol in n-butanol (boiling point 118℃ / 0.1MPaA, 31℃ / 1kPaA) after selective hydrogenation of 1,4-butynediol is fed into decolorization tower 1. Decolorization tower 1 is filled with activated carbon as an adsorbent, and the specific surface area of ​​the activated carbon is 600 m². 2 / g, bulk density 0.7 g / cm³ 3 The decolorization tower 1 operates at a temperature of 90℃, an operating pressure of 0.2 MPaG, and a bed pressure drop of 30 kPa; the first material is output.

[0074] (2) The first material is fed into the first condenser 61 to exchange heat with the second material collected from the side stream of the desolventizing tower 2, and then fed into the desolventizing tower 2 for desolventizing. The top temperature of the tower is 32~37℃, the side stream temperature is 121~126℃, the bottom temperature of the tower is 135~140℃, and the operating pressure is 0.5~2 kPaA. After the top material is condensed, the solvent in the liquid phase is recovered and the second tail gas is collected. After the side stream product is condensed and separated, the first tail gas and the second liquid material are obtained, namely the crude product of 1,4-butenediol. The first heavy component is collected from the bottom of the tower and fed into the waste liquid incinerator.

[0075] (3) The second material is fed into product tower 3 to remove light components and second heavy components. The temperature at the top of the tower is 92~97℃, the temperature at the side stream is 128~133℃, the temperature at the bottom of the tower is 129~134℃, and the operating pressure is 0.5~2kPaA. After the top of the tower is condensed, the fourth tail gas and liquid light component materials (residual solvent, 4-hydroxybutyraldehyde, 1,4-butanediol, etc.) are obtained. After the product in the tower is condensed, the third tail gas and high-purity 1,4-butenediol are obtained. The second heavy component is collected from the bottom of the tower and fed into desolventizing tower 2 to recover 1,4-butenediol.

[0076] (4) The first, second, third, and fourth tail gases are fed into the first inlet at the bottom of the absorption tower 4 to absorb the uncondensed 1,4-butenediol contained therein, forming a rich solvent in the absorption tower 4; the absorbent is n-butanol, the tower bottom temperature is 15~20℃, and the operating pressure is 0.5~2kPaA; when the 1,4-butenediol content in the solution of the absorption tower 4 reaches 20%, the rich absorbent in the absorption tower 4 is fed into the fourth condenser 64 to exchange heat with the material collected from the top of the product tower 3, and then fed into the desolventizing tower 2, while the regenerated absorbent is replenished through the second inlet of the absorption tower 4. The results of this embodiment are shown in Table 12.

[0077] To further verify the superiority of the process conditions of this invention, the R&D team used Aspen Plus software to simulate the operation of the desolventizing tower 2, product tower 3, and absorption tower 4 in this embodiment. The simulation results are shown in Table 5.

[0078] Table 5

[0079] Example 4 A method for online energy saving and scale prevention in a 1,4-butenediol vacuum system includes the following steps: (1) A solution of 1,4-butenediol with cyclohexanol (boiling point 205℃ / 0.1MPaA, 61℃ / 1kPaA) after selective hydrogenation of 1,4-butynediol was fed into decolorization tower 1. Decolorization tower 1 was filled with activated carbon as an adsorbent, and the specific surface area of ​​the activated carbon was 800 m². 2 / g, bulk density 0.52 g / cm³ 3 The decolorization tower 1 operates at a temperature of 75℃, an operating pressure of 0.2 MPaG, and a bed pressure drop of 40 kPa. The output is the first material.

[0080] (2) The first material is fed into the first condenser 61 and exchanges heat with the second material collected from the side stream of the desolventizing tower 2. Then it is fed into the desolventizing tower 2 for desolventizing. The temperature at the top of the tower is 65~70℃, the temperature at the side stream is 127~132℃, the temperature at the bottom of the tower is 136~141℃, and the operating pressure is 0.5~2 kPaA. After the top material is condensed, the solvent in the liquid phase is recovered and the second tail gas is collected. After the side stream product is condensed and separated, the first tail gas and the second material in the liquid phase are obtained, namely the crude product of 1,4-butenediol. The first heavy component is collected from the bottom of the tower and fed into the waste liquid incinerator.

[0081] (3) The second material is fed into product tower 3 to remove light components and second heavy components. The temperature at the top of the tower is 120~125℃, the temperature at the side stream is 128~133℃, the temperature at the bottom of the tower is 130~135℃, and the operating pressure is 0.5~2kPaA. After the top of the tower is condensed, the fourth tail gas and liquid light component materials (residual solvent, 4-hydroxybutyraldehyde, 1,4-butanediol, etc.) are obtained. After the product in the tower is condensed, the third tail gas and high-purity 1,4-butenediol are obtained. The second heavy component is collected from the bottom of the tower and fed into desolventizing tower 2 to recover 1,4-butenediol.

[0082] (4) The first, second, third, and fourth tail gases are fed into the first inlet at the bottom of the absorption tower 4 to absorb the uncondensed 1,4-butenediol contained therein, forming a rich solvent in the absorption tower 4; the absorbent is cyclohexanol, the tower bottom temperature is 30~35℃, and the operating pressure is 0.5~2kPaA; when the 1,4-butenediol content in the solution of the absorption tower 4 reaches 20%, the rich absorbent in the absorption tower 4 is fed into the fourth condenser 64 to exchange heat with the material collected from the top of the product tower 3, and then fed into the desolventizing tower 2, while the regenerated absorbent is replenished through the second inlet of the absorption tower 4. The results of this embodiment are shown in Table 12.

[0083] To further verify the superiority of the process conditions of this invention, the R&D team used Aspen Plus software to simulate the operation of the desolventizing tower 2, product tower 3, and absorption tower 4 in this embodiment. The simulation results are shown in Table 6.

[0084] Table 6

[0085] Example 5 A method for online energy saving and scale prevention in a 1,4-butenediol vacuum system includes the following steps: (1) A solution of 1,4-butenediol with N,N-dimethylformamide (DMF) (boiling point 153℃ / 0.1MPaA, 44℃ / 1kPaA) after selective hydrogenation of 1,4-butynediol was fed into decolorization tower 1. Decolorization tower 1 was filled with activated carbon as an adsorbent, and the specific surface area of ​​the activated carbon was 700 m². 2 / g, bulk density 0.55 g / cm³ 3 The decolorization tower 1 operates at a temperature of 60℃, an operating pressure of 0.1 MPaG, and a bed pressure drop of 30 kPa. The output is the first material.

[0086] (2) The first material is fed into the first condenser 61 to exchange heat with the second material collected from the side stream of the desolventizing tower 2, and then fed into the desolventizing tower 2 for desolventizing. The top temperature of the tower is 45~50℃, the side stream temperature is 121~126℃, the bottom temperature of the tower is 135~140℃, and the operating pressure is 0.5~2 kPaA. After the top material is condensed, the solvent in the liquid phase is recovered and the second tail gas is collected. After the side stream product is condensed and separated, the first tail gas and the second liquid material are obtained, namely the crude product of 1,4-butenediol. The first heavy component is collected from the bottom of the tower and fed into the waste liquid incinerator.

[0087] (3) The second material is fed into product tower 3 to remove light components and second heavy components. The temperature at the top of the tower is 91~96℃, the temperature at the side stream is 128~133℃, the temperature at the bottom of the tower is 130~135℃, and the operating pressure is 0.5~2kPaA. After the top of the tower is condensed, the fourth tail gas and liquid light component materials (residual solvent, 4-hydroxybutyraldehyde, 1,4-butanediol, etc.) are obtained. After the product in the tower is condensed, the third tail gas and high-purity 1,4-butenediol are obtained. The second heavy component is collected from the bottom of the tower and fed into desolventizing tower 2 to recover 1,4-butenediol.

[0088] (4) The first, second, third, and fourth tail gases are fed into the first inlet at the bottom of the absorption tower 4 to absorb the uncondensed 1,4-butenediol contained therein, forming a rich solvent in the absorption tower 4; the absorbent is N,N-dimethylformamide, the tower bottom temperature is 15~20℃, and the operating pressure is 0.5~2kPaA; when the 1,4-butenediol content in the solution of the absorption tower 4 reaches 20%, the rich absorbent in the absorption tower 4 is fed into the fourth condenser 64 to exchange heat with the material collected from the top of the product tower 3, and then fed into the desolventizing tower 2, while the regenerated absorbent is replenished through the second inlet of the absorption tower 4. The results of this embodiment are shown in Table 12.

[0089] To further verify the superiority of the process conditions of this invention, the R&D team used Aspen Plus software to simulate the operation of the desolventizing tower 2, product tower 3, and absorption tower 4 in this embodiment. The simulation results are shown in Table 7.

[0090] Table 7

[0091] Example 6 A method for online energy saving and scale prevention in a 1,4-butenediol vacuum system includes the following steps: (1) A solution of 1,4-butenediol in ethylene glycol monoethyl ether (boiling point 135℃ / 0.1MPaA, 35℃ / 1kPaA) after selective hydrogenation of 1,4-butynediol was fed into decolorization tower 1. Decolorization tower 1 was filled with activated carbon as an adsorbent, and the specific surface area of ​​the activated carbon was 900 m². 2 / g, bulk density 0.5 g / cm³ 3 The decolorization tower 1 operates at a temperature of 75℃, an operating pressure of 0.2 MPaG, and a bed pressure drop of 30 kPa. The output is the first material.

[0092] (2) The first material is fed into the first condenser 61 to exchange heat with the second material collected from the side stream of the desolventizing tower 2, and then fed into the desolventizing tower 2 for desolventizing. The temperature at the top of the tower is 37~42℃, the temperature at the side stream is 121~126℃, the temperature at the bottom of the tower is 134~139℃, and the operating pressure is 0.5~2 kPaA. After the top material is condensed, the solvent in the liquid phase is recovered and the second tail gas is collected. After the side stream product is condensed and separated, the first tail gas and the second material in the liquid phase are obtained, namely the crude product of 1,4-butenediol. The first heavy component is collected from the bottom of the tower and fed into the waste liquid incinerator.

[0093] (3) The second material is fed into product tower 3 to remove light components and second heavy components. The temperature at the top of the tower is 91~96℃, the temperature at the side stream is 128~133℃, the temperature at the bottom of the tower is 130~135℃, and the operating pressure is 0.5~2kPaA. After the top of the tower is condensed, the fourth tail gas and liquid light component materials (residual solvent, 4-hydroxybutyraldehyde, 1,4-butanediol, etc.) are obtained. After the product in the tower is condensed, the third tail gas and high-purity 1,4-butenediol are obtained. The second heavy component is collected from the bottom of the tower and fed into desolventizing tower 2 to recover 1,4-butenediol.

[0094] (4) The first, second, third, and fourth tail gases are fed into the first inlet at the bottom of the absorption tower 4 to absorb the uncondensed 1,4-butenediol contained therein, forming a rich solvent in the absorption tower 4; the absorbent is ethylene glycol monoethyl ether, the tower bottom temperature is 15~20℃, and the operating pressure is 0.5~2kPaA; when the 1,4-butenediol content in the solution of the absorption tower 4 reaches 20%, the rich absorbent in the absorption tower 4 is fed into the fourth condenser 64 to exchange heat with the material collected from the top of the product tower 3, and then fed into the desolventizing tower 2, while the regenerated absorbent is replenished through the second inlet of the absorption tower 4. The results of this embodiment are shown in Table 12.

[0095] To further verify the superiority of the process conditions of this invention, the R&D team used Aspen Plus software to simulate the operation of the desolventizing tower 2, product tower 3, and absorption tower 4 in this embodiment. The simulation results are shown in Table 8.

[0096] Table 8

[0097] Furthermore, in this embodiment, the process of increasing the number of trays in the solvent removal tower 2 to 45 or 50 was also explored, and the simulation results are shown in Table 9.

[0098] Table 9

[0099] Furthermore, this embodiment also explored the process of reducing the number of trays in product tower 3 to 30 or increasing the number of trays in product tower 3 to 40, and the simulation results are shown in Table 10.

[0100] Table 10

[0101] Example 7 A method for online energy saving and scale prevention in a 1,4-butenediol vacuum system is disclosed. The process steps and parameter control in this embodiment are the same as in Example 2, except that the crude 1,4-butenediol product solution to be purified is prepared by butadiene acetoxylation. The results of this embodiment are shown in Table 12.

[0102] To further verify the superiority of the process conditions of this invention, the R&D team used Aspen Plus software to simulate the operation of the desolventizing tower 2, product tower 3, and absorption tower 4 in this embodiment. The simulation results are shown in Table 11.

[0103] Table 11

[0104] Example 8 A method for online energy saving and scale prevention in a 1,4-butenediol vacuum system is disclosed. The process steps and parameter control in this embodiment are the same as in Embodiment 2, except that the adsorbent packed in absorption tower 4 is a macroporous resin, and the composition of the crude 1,4-butenediol product solution to be purified is shown in Table 2. The results of this embodiment are shown in Table 12.

[0105] Example 9 A method for purifying 1,4-butenediol is described in this embodiment. The process steps and parameter control are the same as in Example 2, except that when the 1,4-butenediol content in absorber 4 reaches 40%, it is then fed into desolvation tower 2 to regenerate the absorbent. After 160 hours of operation, the system pressure increased by 300-400 Pa, and after 200 hours of stable operation, vacuum pump 51 remained unblocked.

[0106] Example 10 A method for refining 1,4-butenediol is disclosed in this embodiment. The process steps and parameter control are the same as in Example 2. The difference lies in that when the 1,4-butenediol content in absorber 44 reaches 10%, it is fed into desolvation tower 2 to regenerate the absorbent. In this embodiment, the 1,4-butenediol content in absorber 4 is lower, which has little impact on the purity and color of 1,4-butenediol. The main difference is that the oil in vacuum pump 51 is lighter in color, resulting in a more significant anti-clogging effect, but the overall operating cost increases.

[0107] Comparative Example 1 A method for purifying 1,4-butenediol. The process steps and parameter control in this embodiment are the same as in Example 2, except that a decolorization tower 1 is not set up.

[0108] Comparative Example 2 A method for purifying 1,4-butenediol is described in this embodiment. The process steps and parameter control are the same as in Example 2, except that tail gas absorption is not performed. During the operation of this example, butenediol polymerizes in vacuum pump 51, generating a viscous substance that clogs vacuum pump 51. After 150 hours of operation, the vacuum level drops significantly, making it impossible to continue operation.

[0109] Comparative Example 3 A method for purifying 1,4-butenediol. The process steps and parameter control in this embodiment are the same as in Example 2. The difference is that the crude 1,4-butenediol product solution to be purified is prepared by the 1,4-dichloro-2-butene method. This method requires hydrolysis under alkaline conditions, which generates a large amount of waste salt. After hydrolysis, 1,4-butenediol is extracted with ethylene glycol diethyl ether, followed by decolorization and distillation.

[0110] The present invention statistically analyzed the process operation data of Examples 1-10 and Comparative Examples 1-3, and the results are shown in Table 12.

[0111] Table 12

[0112] As can be seen from Table 12, the online energy-saving and anti-scaling method of the 1,4-butenediol vacuum system 5 of the present invention can obtain high-purity, low-color 1,4-butenediol products, which can meet the needs of subsequent preparation of other products using 1,4-butenediol as raw material. Moreover, the vacuum pump 51 of the whole process runs well for a long time, and there is no blockage of the vacuum pump 51 during the operation time of more than 200 hours. While reducing energy consumption, the system can run continuously and stably for a long time.

[0113] Furthermore, the purity of the 1,4-butenediol products obtained by Aspen Plus software in each embodiment of the present invention is consistent with the actual measurement results of the corresponding embodiments, which confirms the reliability and reproducibility of the process conditions of the present invention and has important industrial application value.

[0114] It should be noted that the above description is a further detailed explanation of the present invention in conjunction with specific embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple improvements can be made without departing from the concept of the present invention, and all such improvements should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for online energy saving and scale prevention in a 1,4-butenediol vacuum system, characterized in that, Includes the following steps: (1) The crude product solution of 1,4-butenediol is fed into a decolorization tower filled with adsorbent and the first material is obtained after decolorization treatment; (2) The first material is fed into the solvent removal tower to remove the solvent. The material taken from the side line of the solvent removal tower is condensed and separated to obtain the first tail gas and the second material in liquid phase. The material taken from the top of the tower is condensed and separated to obtain the second tail gas and the regenerated solvent in liquid phase. The first heavy component is taken from the bottom of the tower. (3) The second material is fed into the product tower. The material taken from the side line of the product tower is condensed and separated to obtain the third tail gas and liquid phase high-purity 1,4-butenediol product. The material taken from the top of the tower is condensed and separated to obtain the fourth tail gas and liquid phase light component material. The second heavy component is taken from the bottom of the tower. (4) The first tail gas, the second tail gas, the third tail gas and the fourth tail gas are fed into the absorption tower and contacted with the lean absorbent in the absorption tower. The fifth tail gas obtained after the top product of the absorption tower is condensed and separated is fed into the vacuum system. The rich absorbent collected from the bottom of the absorption tower is fed into the desolventizing tower, and at least a portion of the regenerated solvent is transported to the absorption tower as a lean solvent.

2. The method for online energy saving and scale prevention of the 1,4-butenediol vacuum system according to claim 1, characterized in that, The first material and the material drawn from the side stream of the desolventizing tower are coupled through a heat exchanger to condense and separate the material drawn from the side stream of the desolventizing tower. And / or, the rich absorbent drawn from the bottom of the absorption tower and the material drawn from the top of the product tower are coupled by heat exchange through a heat exchanger to condense and separate the material drawn from the top of the product tower.

3. The method for online energy saving and scale prevention of the 1,4-butenediol vacuum system according to claim 1, characterized in that, The 1,4-butenediol content in the crude 1,4-butenediol solution is 20wt%~60wt%, preferably 30wt%~50wt%. Preferably, the crude 1,4-butenediol product solution is prepared by the 1,4-butynediol method or the butadiene acetoxylation method; And / or, the solvent of the crude 1,4-butenediol product solution is selected from at least one of alcohols, ethers, and amides with a boiling point of 100-205°C; Preferably, the alcohol includes high-boiling-point monohydric alcohols and dihydric alcohols, more preferably isobutanol, n-butanol, n-pentanol, n-hexanol, 2-hexanol, cyclohexanol, benzyl alcohol, n-octanol, isooctanol, ethylene glycol, 1,2-propanediol, and 1,2-butanediol, and even more preferably ethylene glycol and 1,2-propanediol. Preferably, the ether comprises at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether, and more preferably ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol diethyl ether. Preferably, the amide includes at least one of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, and N,N-diethylacetamide, and more preferably N,N-dimethylformamide.

4. The method for online energy saving and scale prevention of the 1,4-butenediol vacuum system according to claim 1, wherein the theoretical plate number of the solvent removal tower is 40-50, preferably 43-47; Preferably, the first material is fed into the 10th to 15th tray; Preferably, the side stream sampling point of the solvent removal tower is 15 to 25 trays; And / or, the top temperature of the solvent removal column is 25~100℃, the side stream temperature is 115~135℃, the bottom temperature is 130~145℃, the operating pressure is 0.2~5kPaA, preferably 0.5~2kPaA, and the reflux ratio is 0.5~10.

5. The method for online energy saving and scale prevention of the 1,4-butenediol vacuum system according to claim 1, wherein the theoretical number of trays in the product tower is 35-45, preferably 38-42; Preferably, the feeding position of the second material is the 10th to 15th tray; Preferably, the side sampling location of the product tower is 30 to 40 trays; And / or, the product column has a top temperature of 50~135℃, a side stream temperature of 125~135℃, a bottom temperature of 128~140℃, an operating pressure of 0.2~5kPaA, preferably 0.5~2kPaA, and a reflux ratio of 0.5~10.

6. The method for online energy saving and scale prevention of the 1,4-butenediol vacuum system according to claim 1, characterized in that, The absorption tower has a top temperature of 0~20℃, a bottom temperature of 5~35℃, and an operating pressure of 0.2~5kPaA, preferably 0.5~2kPaA; And / or, the mass concentration of 1,4-butenediol in the rich absorbent is 10% to 40%, preferably 20% to 30%.

7. The method for online energy saving and scale prevention of the 1,4-butenediol vacuum system according to claim 1, characterized in that, The adsorbent is a macroporous adsorption resin or activated carbon. Preferably, the specific surface area of ​​the activated carbon is 600~1200 m². 2 / g, preferably 800~1000m 2 / g; bulk density is 0.4~0.7g / cm³ 3 The preferred concentration is 0.5~0.6 g / cm³. 3 ; And / or, the operating temperature of the decolorization tower is 60~90℃, preferably 70~80℃; the operating pressure is 0.1~0.3MPaG, preferably 0.2~0.3MPaG; and the volumetric hourly space velocity is 0.5~2h. -1 Preferably 1~1.5h -1 .

8. The method for online energy saving and scale prevention of the 1,4-butenediol vacuum system according to claim 1, characterized in that, The second heavy component is input into the desolventizing tower; And / or, the vacuum system includes a vacuum pump, and the exhaust gas from the top of the absorption tower is fed into the vacuum pump after cryogenic treatment.

9. A device for online energy saving and scale prevention in a 1,4-butenediol vacuum system, characterized in that, Includes a decolorization tower, a solvent removal tower, a product tower, an absorption tower, and a vacuum system; among which: The feed inlet of the decolorization tower is used to input the crude 1,4-butenediol product solution to be purified, and the bottom of the decolorization tower is connected to the feed inlet of the desolventizing tower. The side outlet of the solvent removal tower is connected to the first condenser, and the liquid phase outlet of the first condenser is connected to the feed inlet of the product tower; the top of the solvent removal tower is connected to the second condenser, and the liquid phase outlet of the second condenser is used to collect the regenerated solvent. The side outlet of the product tower is connected to a third condenser, and the liquid phase outlet of the third condenser produces high-purity 1,4-butenediol product; the top of the product tower is connected to a fourth condenser, and the liquid phase outlet of the fourth condenser is used to produce light component materials. The gas phase outlets of the first condenser, the second condenser, the third condenser, and the fourth condenser are connected to the first feed inlet of the absorption tower. The top of the absorption tower is connected to a fifth condenser, and the gas phase outlet of the fifth condenser is connected to the vacuum system. The bottom of the absorption tower is connected to the feed inlet of the solvent removal tower. The liquid phase outlet of the second condenser is connected to the second feed inlet of the absorption tower via a first branch, thereby inputting a portion of the regenerated solvent into the absorption tower as a lean solvent.

10. The online energy-saving and scale-preventing device for the 1,4-butenediol vacuum system according to claim 9, characterized in that, The rich absorbent output from the bottom of the absorption tower is connected to the inlet of the desolventizing tower after heat exchange in the fourth condenser. And / or, the bottom of the decolorization tower is connected to the solvent removal tower via the refrigerant channel of the first condenser; And / or, the bottom of the absorption tower is connected to the solvent removal tower via the refrigerant channel of the fourth condenser; And / or, the bottom outlet of the product column is connected to the feed inlet of the desolventizing column; And / or, the vacuum system includes a cryostat and a vacuum pump; the gas phase outlet of the fifth condenser is connected to the cryostat, and the gas phase outlet of the cryostat is connected to the vacuum pump.

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