Tetrahydrofuran purification method and application

Abstract

The invention belongs to the technical field of chemical solvent preparation, and particularly relates to a tetrahydrofuran purification method and application. The invention provides a tetrahydrofuran purification method which comprises the following steps: performing catalytic hydrogenation reaction on tetrahydrofuran gas containing impurities under the action of a catalyst to obtain a gaseous first product and liquid tetrahydrofuran; and mixing the gaseous first product with an absorbent to obtain a gaseous second product and liquid tetrahydrofuran. The invention also provides an application of the purification method in preparation of tetrahydrofuran. In the application, through catalytic hydrotreatment, the impurity dihydrofuran in tetrahydrofuran is hydrogenated to generate tetrahydrofuran, the impurities n-butyraldehyde and isobutyraldehyde are hydrogenated to generate alcohols which are easy to separate from tetrahydrofuran, and the content of the impurity dihydrofuran in the purified tetrahydrofuran is reduced to 3 ppm or less. According to the tetrahydrofuran purification method and the application provided by the invention, the technical defect that in the prior art, a tetrahydrofuran refining process is tedious in process flow is overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical solvent preparation, and in particular to a tetrahydrofuran purification method and application. Background Art

[0002] Tetrahydrofuran is an excellent organic solvent widely used in industrial production. It has the characteristics of low toxicity, low boiling point, good fluidity and excellent solubility, and has a very wide range of applications. The prepared tetrahydrofuran generally contains dihydrofuran and aldehyde-alcohol impurities that are difficult to separate, and has problems such as low purity and environmental pollution.

[0003] Removing the above impurities is particularly important for the tetrahydrofuran refining process. In the prior art, the tetrahydrofuran refining process is to contact the aqueous tetrahydrofuran with a strongly acidic cation exchange resin to convert the dihydrofuran in the tetrahydrofuran into hydroxytetrahydrofuran. The process is divided into a dihydrofuran removal process, an aldehyde removal process, a dehydration process and a subsequent deacidification and hydrogenation process, and the process flow is relatively long.

[0004] Therefore, developing a tetrahydrofuran purification method and application to solve the technical defects of the prior art, that is, the complicated process flow of the tetrahydrofuran refining process, has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0005] Based on this, it is necessary to provide a tetrahydrofuran purification method and application to address the technical defects of the existing technology in the cumbersome process flow of tetrahydrofuran refining process.

[0006] The present application provides a method for purifying tetrahydrofuran, the purification method comprising:

[0007] Step 1: The tetrahydrofuran gas containing impurities undergoes a catalytic hydrogenation reaction under the action of a catalyst to obtain a gaseous first product and liquid tetrahydrofuran;

[0008] Step 2: The gaseous first product is mixed with an absorbent to obtain a gaseous second product and liquid tetrahydrofuran.

[0009] In one embodiment, in step 1, the catalyst is any one or more of a nickel-based catalyst, a palladium-based catalyst, a ruthenium-based catalyst and platinum.

[0010] In one embodiment, step one further comprises: catalyst activation, wherein the catalyst is activated in an activation gas atmosphere.

[0011] In one embodiment, the activation gas is nitrogen and / or hydrogen.

[0012] In one embodiment, the activation temperature is 180-220° C., and the activation pressure is 0.01-0.1 MPa.

[0013] In one embodiment, in step one, the reducing gas of the catalytic hydrogenation reaction is hydrogen, and the ventilation rate of hydrogen is.

[0014] In one embodiment, in step 1, the temperature of the catalytic hydrogenation reaction is 70-140° C., and the pressure of the catalytic hydrogenation reaction is 0.4-1.0 MPa.

[0015] In one embodiment, in step 2, the absorbent includes: desalted water and / or tetrahydrofuran solution.

[0016] The present application also provides an application of any one of the above purification methods in the preparation of tetrahydrofuran.

[0017] In summary, the present application provides a method for purifying tetrahydrofuran, comprising: catalytic hydrogenation reaction of tetrahydrofuran gas containing impurities under the action of a catalyst to obtain a gaseous first product and liquid tetrahydrofuran; mixing the gaseous first product with an absorbent to obtain a gaseous second product and liquid tetrahydrofuran. The present application also provides an application of the above-mentioned purification method in the preparation of tetrahydrofuran. In the technical scheme provided by the present application, the impurity dihydrofuran in tetrahydrofuran is hydrogenated to generate tetrahydrofuran through catalytic hydrogenation treatment, and the impurities n-butyraldehyde and isobutyraldehyde are hydrogenated to generate alcohols that are easily separated from tetrahydrofuran. After measurement, the content of the impurity dihydrofuran in the purified tetrahydrofuran is reduced to less than 3ppm, and the alcohols are separated in the deweighting tower, which effectively improves the purity and quality of tetrahydrofuran, and also has the advantages of simple purification device structure and purification process, low energy consumption and no additional environmental pollution. A method for purifying tetrahydrofuran and its application provided by the present application solve the technical defects of the cumbersome process flow of the tetrahydrofuran refining process in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0019] Figure 1 A schematic structural diagram of a tetrahydrofuran purification device used in a tetrahydrofuran purification method provided in an embodiment of the present application;

[0020] Among them, there are catalytic hydrogenation reaction part A, absorption tower B and heat exchanger C. DETAILED DESCRIPTION

[0021] The embodiments of the present application provide a tetrahydrofuran purification method and application, which are used to solve the technical defects of the prior art in the tetrahydrofuran refining process, which is complicated.

[0022] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0023] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0024] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0025] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0026] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0027] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0028] In order to more clearly illustrate the tetrahydrofuran purification method provided by the present application, a brief description of the purification device used in the aforementioned purification method is given below.

[0029] See also Figure 1 In the tetrahydrofuran purification method of the embodiment of the present application, the tetrahydrofuran purification device used includes: a feed inlet, a catalytic hydrogenation reaction part A, a gas phase discharge port, a liquid phase discharge port, a deweighting tower and an absorption tower, the feed inlet is connected with the catalytic hydrogenation reaction part A, the catalytic hydrogenation reaction part A is connected with the deweighting tower through the liquid phase discharge port, and the catalytic hydrogenation reaction part is connected with the absorption tower through the gas phase discharge port; the absorption tower includes: a hollow cavity, an absorption part, a gaseous discharge end and a liquid discharge end, the absorption part is arranged inside the hollow cavity, the liquid discharge end is arranged at the bottom end of the hollow cavity, and the gaseous discharge end is arranged at the top end of the hollow cavity.

[0030] In the present application, tetrahydrofuran gas 1 containing impurities enters from the lower end of the catalytic hydrogenation reaction section A. At this time, tetrahydrofuran does not undergo any reaction in the catalytic hydrogenation reaction section A, and the impurity dihydrofuran undergoes a reduction hydrogenation reaction in the catalytic hydrogenation reaction section to generate tetrahydrofuran. At the same time, aldehyde impurities that are difficult to separate from tetrahydrofuran, such as n-butyraldehyde and isobutyraldehyde, undergo a reduction hydrogenation reaction in the catalytic hydrogenation reaction section A to generate alcohol.

[0031]

[0032] After the hydrogenation is completed in the catalytic hydrogenation reaction part A, the liquid phase product 4 enters the de-weighting tower through the liquid phase outlet, and the heavy alcohols are removed in the de-weighting tower to obtain purified tetrahydrofuran. The gas phase product 5 enters the absorption tower B through the gas phase outlet.

[0033] The gas phase product 5 absorbs the residual tetrahydrofuran in the gas phase product 5 in the absorption part of the absorption tower B, and flows out through the liquid discharge end of the absorption tower B, and the absorbed tetrahydrofuran liquid 8 is collected. The remaining gas 7 passing through the absorption tower B escapes through the gas discharge end of the absorption tower B.

[0034] In the technical solution provided by the present application, in order to effectively ensure the catalytic speed of the catalytic hydrogenation reaction unit A, ensure that the impurities dihydrofuran and aldehyde in tetrahydrofuran can be fully reduced, and ensure a good purification effect on tetrahydrofuran, in the technical solution provided by the embodiment of the present application, the catalytic hydrogenation reaction unit is a bubbling bed reactor and / or a trickle bed reactor. The bubbling bed reactor and / or the trickle bed reactor can make the impurities in tetrahydrofuran fully contact with the catalyst to achieve the best reduction effect.

[0035] In the actual application process, in order to avoid the temperature of the impure tetrahydrofuran gas 1 affecting the catalytic hydrogenation reaction part A, and reduce the reaction rate and catalyst activity of the catalytic hydrogenation reaction part A, in the embodiment of the present application, the purification device also includes: a heat exchanger C, which is arranged between the feed port and the catalytic hydrogenation reaction part. Before the impure tetrahydrofuran gas 1 enters the catalytic hydrogenation reaction part A, the temperature will be reduced to a suitable range through the heat exchanger, and the low-temperature impure tetrahydrofuran liquid 2 enters the catalytic hydrogenation reaction part A.

[0036] To further optimize the technical solution, in order to ensure that the reduction reaction in the catalytic hydrogenation reaction part A is completed efficiently and quickly, a purification device of the present application also includes: a reducing gas feed port and a micro-nano bubble generator; the reducing gas passes through the micro-nano bubble generator and the reducing gas feed port in sequence, and the reducing gas feed port is connected to the catalytic hydrogenation reaction part. Reducing gas 3 is introduced into the catalytic hydrogenation reaction part A through the reducing gas feed port. In order to allow the reducing gas 3 to fully contact with the catalyst and impurities in the catalytic hydrogenation reaction part A, before the reducing gas 3 enters the catalytic hydrogenation reaction part A, it is processed by the micro-nano bubble generator, so that the reducing gas 3 entering the catalytic hydrogenation reaction part A has the characteristics of large specific surface area, slow rising speed, high surface charge, and high gas solubility rate, thereby effectively promoting the rapid and efficient progress of catalytic hydrogenation.

[0037] To further optimize the technical solution, in order to effectively improve the activity of the catalyst in the catalytic hydrogenation reaction section A, a purification device of the present application also includes: a catalytic activation section, which is connected to the bottom end of the catalytic hydrogenation reaction section; and the catalytic activation section provides an activation gas source for the catalytic hydrogenation reaction section.

[0038] In the technical solution provided in the embodiment of the present application, a gas-liquid diverter is provided on the top of the catalytic hydrogenation reaction part, and the fluid after the reaction in the catalytic hydrogenation reaction part passes through the gas-liquid diverter and enters the gas phase discharge port and the liquid phase discharge port respectively. The gas-liquid diverter can realize the rapid and effective separation of gas phase and liquid phase products, ensuring that tetrahydrofuran and alcohol obtained by reducing impurity aldehydes can smoothly enter the deweighting tower.

[0039] Specifically, the interior of the gas-liquid diversion trough is a double-layer structure with a porous partition in the middle. The upper outlet is a gas phase outlet, and the lower outlet is a liquid phase outlet. A condensation jacket layer can be optionally provided outside the gas-liquid diversion trough, and condensed water is introduced into the condensation jacket layer.

[0040] To further optimize the technical solution, in order to prevent the holes in the gas-liquid diversion trough from being blocked and to improve the gas-liquid separation effect, a filter section is provided in the gas-liquid diversion trough, and a porous filter material is provided in the filter section, which can be common filter materials such as activated carbon and porous ceramics.

[0041] The purification device used in the embodiment of the present application also includes: a combustion part, which is connected to the gas phase discharge port. After the remaining gas 7 from the absorption tower B escapes through the gaseous discharge end of the absorption tower B, it is fully burned in the combustion part to prevent the gas 7 from remaining in the air for a long time and polluting the environment.

[0042] In order to effectively improve safety, the purification device used in the present application also includes: a voltage stabilizing unit, which is arranged between the gaseous discharge end and the ignition module. The voltage stabilizing unit provides gas 9, which is mixed with gas 7 to maintain a stable pressure, ensuring that the gas pressure is constant during the combustion process of the combustion unit, making the combustion process safer and avoiding dangerous situations such as explosion during the combustion process.

[0043] In order to effectively optimize the absorption effect of the absorption tower on residual tetrahydrofuran, in the technical solution provided in the embodiment of the present application, the absorption tower B is a packed tower and / or a plate tower.

[0044] To further optimize the technical solution, in a purification device provided in an embodiment of the present application, the absorption tower is a packed tower, the packing height of the packed tower is 4 to 8 meters, and the packing types of the packed tower include wire mesh type structured packing and / or corrugated plate structured packing, for example: CY wire mesh type structured packing and / or BX type plate corrugated structured packing of Sursour Company.

[0045] In combination with the above-mentioned tetrahydrofuran purification device, a tetrahydrofuran purification method provided in an embodiment of the present application is further described, and the purification method comprises:

[0046] Step 1: The tetrahydrofuran gas containing impurities undergoes a catalytic hydrogenation reaction under the action of a catalyst to obtain a gaseous first product and liquid tetrahydrofuran;

[0047] Step 2: The gaseous first product is mixed with the absorbent 6 to obtain a gaseous second product and liquid tetrahydrofuran.

[0048] In the present application, tetrahydrofuran gas 1 containing impurities enters from the lower end of the catalytic hydrogenation reaction section A. At this time, tetrahydrofuran does not undergo any reaction in the catalytic hydrogenation reaction section A, and the impurity dihydrofuran undergoes a reduction hydrogenation reaction in the catalytic hydrogenation reaction section to generate tetrahydrofuran. At the same time, aldehyde impurities that are difficult to separate from tetrahydrofuran, such as n-butyraldehyde and isobutyraldehyde, undergo a reduction hydrogenation reaction in the catalytic hydrogenation reaction section A to generate alcohol.

[0049]

[0050] After the hydrogenation is completed in the catalytic hydrogenation reaction part A, the liquid phase product 4 enters the de-weighting tower through the liquid phase outlet, and the heavy alcohols are removed in the de-weighting tower to obtain purified tetrahydrofuran. The gas phase product 5 enters the absorption tower B through the gas phase outlet.

[0051] The gas phase product 5 absorbs the residual tetrahydrofuran in the gas phase product 5 in the absorption part of the absorption tower B, and flows out through the liquid discharge end of the absorption tower B, and the purified tetrahydrofuran liquid 8 obtained by absorption is collected. The remaining gas 7 passing through the absorption tower B escapes through the gas discharge end of the absorption tower B.

[0052] On the basis of ensuring good catalytic hydrogenation effect of the catalyst, taking into account the comprehensive consideration of catalyst cost and catalyst life, in the purification method provided in the embodiment of the present application, in step one, the catalyst is any one or more of a nickel-based catalyst, a palladium-based catalyst, a ruthenium-based catalyst and platinum.

[0053] To further optimize the technical solution, the catalyst is activated in an activation gas atmosphere to achieve the optimal catalytic effect of the catalyst. In the technical solution provided in the embodiment of the present application, step one also includes: catalyst activation, and the catalyst is activated in an activation gas atmosphere.

[0054] In order to further optimize the technical solution and ensure that the activation gas has a good activation effect on the catalyst, the activation gas cost and safety factors are taken into consideration. In the technical solution provided in the embodiment of the present application, the activation gas is: nitrogen and / or hydrogen.

[0055] Similarly, in the purification method provided in the embodiment of the present application, the activation temperature is 180-220° C., and the activation pressure is 0.01-0.1 MPa.

[0056] In order to ensure a good reduction effect of the catalyst hydrogenation while taking into account the economic feasibility of the purification cost, in the technical solution provided in the embodiment of the present application, in step one, the reducing gas of the catalytic hydrogenation reaction is hydrogen, and the ventilation volume of the hydrogen is.

[0057] Similarly, in the purification method provided in the embodiment of the present application, in step 1, the temperature of the catalytic hydrogenation reaction is 70 to 140° C., and the pressure of the catalytic hydrogenation reaction is 0.4 to 1.0 MPaG.

[0058] To enhance the absorption effect of the absorption tower B on the residual tetrahydrofuran, the absorption tower B contains an absorbent 6. In the actual application process, in step 2, the absorbent 6 includes: desalted water and / or tetrahydrofuran solution.

[0059] According to actual operation tests, the purification method provided by the present application can effectively purify tetrahydrofuran prepared by the cyclization reaction of 1,4-butanediol, and reduce the content of dihydrofuran containing 10 to several thousand ppm of impurities to less than 3 ppm. At the same time, aldehydes that are difficult to separate from tetrahydrofuran can be reduced to generate alcohol substances that are easy to separate, which has a significant effect on improving the purity and quality of tetrahydrofuran, and effectively improves the quality of tetrahydrofuran products.

[0060] Meanwhile, during the entire purification process, there is basically no loss of tetrahydrofuran, thereby ensuring the yield of tetrahydrofuran; during the purification process, no by-products are generated, the environment will not be polluted, and the method can be widely used in the preparation of tetrahydrofuran.

[0061] In summary, the present application provides a method for purifying tetrahydrofuran, comprising: catalytic hydrogenation reaction of tetrahydrofuran gas containing impurities under the action of a catalyst to obtain a gaseous first product and liquid tetrahydrofuran; mixing the gaseous first product with an absorbent to obtain a gaseous second product and liquid tetrahydrofuran. The present application also provides an application of the above-mentioned purification method in the preparation of tetrahydrofuran. In the technical scheme provided by the present application, the impurity dihydrofuran in tetrahydrofuran is hydrogenated to generate tetrahydrofuran through catalytic hydrogenation treatment, and the impurities n-butyraldehyde and isobutyraldehyde are hydrogenated to generate alcohols that are easily separated from tetrahydrofuran. After measurement, the content of the impurity dihydrofuran in the purified tetrahydrofuran is reduced to less than 3ppm, and the alcohols are separated in the deweighting tower, which effectively improves the purity and quality of tetrahydrofuran, and also has the advantages of simple purification device structure and purification process, low energy consumption and no additional environmental pollution. A method for purifying tetrahydrofuran and its application provided by the present application solve the technical defects of the cumbersome process flow of the tetrahydrofuran refining process in the prior art.

[0062] The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. At the same time, other implementation methods can be derived from the above-mentioned embodiments, so that structural and logical replacements and changes can be made without departing from the scope of this disclosure.

[0063] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for purifying tetrahydrofuran, characterized in that: The purification method comprises: Step 1: The tetrahydrofuran gas containing impurities undergoes a catalytic hydrogenation reaction under the action of a catalyst to obtain a gaseous first product and liquid tetrahydrofuran; Step 2: The gaseous first product is mixed with an absorbent to obtain a gaseous second product and liquid tetrahydrofuran.

2. The purification method according to claim 1, characterized in that In step 1, the catalyst is any one or more of a nickel-based catalyst, a palladium-based catalyst, a ruthenium-based catalyst and platinum.

3. The purification method according to claim 1, characterized in that Step one also includes: catalyst activation, in which the catalyst is activated in an activation gas atmosphere.

4. The purification method according to claim 3, characterized in that The activation gas is nitrogen and / or hydrogen.

5. The purification method according to claim 3 or 4, characterized in that The activation temperature is 180-220° C., and the activation pressure is 0.01-0.1 MPa.

6. The purification method according to claim 1, characterized in that In step 1, the reducing gas for the catalytic hydrogenation reaction is hydrogen.

7. The purification method according to claim 1 or 6, characterized in that: In step 1, the temperature of the catalytic hydrogenation reaction is 70-140° C., and the pressure of the catalytic hydrogenation reaction is 0.4-1.0 MPaG.

8. The purification method according to claim 1, characterized in that In step 2, the absorbent includes: desalted water and / or tetrahydrofuran solution.

9. Use of the purification method according to any one of claims 1 to 8 in the preparation of tetrahydrofuran.

Images