Purification system of crude n-butyl alcohol

Abstract

The utility model belongs to the technical field of chemical engineering, and particularly provides a crude n-butyl alcohol purification system which comprises a dehydration device, a first preheater, a hydrogenation reactor, a gas-liquid separation tank and a rectifying tower which are connected in sequence, the dehydration device comprises n membrane assemblies; the hydrogenation reactor is connected with a hydrogen conveying pipe, the hydrogenation reactor is connected with a reactor input pipe, and the bottom of the hydrogenation reactor is connected with a reactor output pipe; the top of the gas-liquid separation tank is connected with the first condenser, and a separation tank conveying pipe is arranged at the bottom of the gas-liquid separation tank; the top of the rectifying tower is provided with a tower top condenser; the bottom of the rectifying tower is connected with a heating device. The system disclosed by the utility model is used for purifying the crude n-butyl alcohol, unsaturated coloring functional groups in the crude n-butyl alcohol can be efficiently removed, the difficulty of rectification separation is reduced, the purified n-butyl alcohol meets the requirements of color number and sulfuric acid color development test, and the system has the advantages of simple production process and low energy consumption.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical industry, and specifically provides a crude n-butanol purification system. Background Art

[0002] my country is a major producer of BDO (1,4-Butanediol). Industrial BDO production processes primarily include the Reppe process and the maleic anhydride process. Both processes produce a certain amount of n-butanol. The crude n-butanol produced as a byproduct of the Reppe BDO process contains 1% to 10% butanol, while the byproduct of the maleic anhydride process contains ≥30% n-butanol. This crude n-butanol contains various impurities, including water, propanol, methanol, and other aldehydes. This crude butanol not only contains a miscible, constant-boiling butanol-water system but also contains other light impurities such as methanol, propanol, and tetrahydrofuran. Its complex physical properties make it difficult to separate, making the purification of n-butanol a long-standing challenge in producing high-quality butanol. Existing treatment methods typically increase the butanol concentration through distillation and then combine it with physical adsorption to eliminate odor and impurities. This results in complex processes, high energy consumption, and the need for frequent replacement of adsorption materials. Although the concentration of n-butanol after secondary purification is increased, trace impurities remain difficult to remove, failing to meet the color number and sulfuric acid colorimetric requirements of GB / T6027-2023, and thus hindering product added value. Due to the high energy consumption, complex processes, high investment, and low product quality of existing purification technologies, which make it difficult to meet national standards, treatment often relies on inexpensive fuel, resulting in significant waste of resources.

[0003] n-Butanol (CH3CH2CH2CH2OH) is widely used in the chemical, pharmaceutical, food, and even energy sectors. Its widespread application and consumption have garnered significant attention in both industrial production and scientific research. n-Butanol is an important organic chemical raw material, serving as a solvent for various coatings and a raw material for plasticizers. It is primarily used in the production of plasticizers such as dibutyl phthalate (DBP), as well as butyl acetate, butyl acrylate, and butyl methacrylate. It is also commonly used as an organic synthesis intermediate and an extractant for biochemical drugs. It is also used in the manufacture of surfactants.

[0004] Therefore, with the rapid development of the BDO industry, how to improve the quality of by-product n-butanol and reduce production costs is of great significance. Utility Model Content

[0005] In order to overcome the above-mentioned defects, the utility model proposes a purification system for crude n-butanol. By adopting the purification system of the utility model, after the crude n-butanol is purified, the obtained n-butanol product not only has high purity, but also shows better performance in color number and sulfuric acid color development test.

[0006] In a first aspect, the present invention provides a crude n-butanol purification system, comprising: a dehydration device, a first preheater, a hydrogenation reactor, a gas-liquid separation tank, and a distillation tower connected in sequence; the dehydration device comprises a plurality of membrane modules connected in sequence, the number of the membrane modules being n, where n is a natural number and satisfies 2≤n≤5, and the bottom of each membrane module is connected to a permeate collection tank;

[0007] The upper portion of the hydrogenation reactor is connected to a hydrogen delivery pipe, the top of the hydrogenation reactor is connected to a reactor input pipe for connecting to the first preheater, and the bottom of the hydrogenation reactor is connected to a reactor output pipe for connecting to a gas-liquid separation tank;

[0008] The top of the gas-liquid separation tank is connected to the first condenser, and the bottom of the gas-liquid separation tank is provided with a separation tank delivery pipe for connecting to the middle of the distillation tower;

[0009] A top condenser is provided at the top of the distillation tower, and a heating device is connected to the bottom of the distillation tower.

[0010] Furthermore, the system also includes: a material conveying pump and a second preheater; wherein the material conveying pump is used to convey the crude n-butanol to be purified, the material conveying pump is connected to one end of the second preheater, and the other end of the second preheater is connected to the dehydration device.

[0011] Furthermore, the system further comprises: an evaporator superheater and a second condenser; the dehydration device comprises a first membrane assembly, a second membrane assembly, a third membrane assembly, a fourth membrane assembly and a fifth membrane assembly connected in sequence;

[0012] One end of the evaporator superheater is connected to the second preheater, the other end of the evaporator superheater is connected to the liquid inlet of the first membrane assembly, and the liquid outlet of the fifth membrane assembly is connected to the second preheater, the second condenser and the first preheater in sequence.

[0013] Furthermore, the reactor output pipe is also connected to a filter.

[0014] Furthermore, a reboiler is connected to the bottom of the distillation tower.

[0015] Furthermore, the system also includes: a full condenser, a distillate tank and a distillate delivery pump; wherein, the top condenser includes a first liquid outlet and a second liquid outlet, the first liquid outlet is connected to the distillate tank, the second liquid outlet is connected to the distillate tank, the liquid outlet of the full condenser is connected to the liquid inlet of the distillate tank, the liquid outlet of the distillate tank is connected to the liquid inlet of the distillate delivery pump, and the liquid outlet of the distillate delivery pump is connected to the top of the distillation tower.

[0016] Furthermore, the system also includes: a n-butanol purified liquid delivery pump and a n-butanol cooler; wherein, one end of the n-butanol purified liquid delivery pump is connected to the middle or upper part of the distillation tower, and the other end of the n-butanol purified liquid delivery pump is connected to the n-butanol cooler.

[0017] Furthermore, the system further comprises: a steam jet vacuum pump, a jet pump condenser and a condensate collection tank; wherein the permeate collection tank, the steam jet vacuum pump, the jet pump condenser and the condensate collection tank are connected in sequence.

[0018] Furthermore, the system also includes: a bottom liquid delivery pump and a bottom liquid cooler; wherein the liquid inlet of the bottom liquid delivery pump is connected to the bottom of the distillation tower, and the bottom liquid cooler is connected to the liquid outlet of the bottom liquid delivery pump.

[0019] The above one or more technical solutions of the present invention have at least one or more of the following beneficial effects:

[0020] 1. High-efficiency decolorization: Through the scientific design of the processing equipment, the utility model system can effectively eliminate the unsaturated bonds in the crude n-butanol, reduce the color number of the butanol, make it meet the requirements of Type I of GB / T6027-2023 "Industrial n-butanol", and improve the appearance quality of the product.

[0021] 2. High-purity output: After being processed by the purification system of the utility model, the purity of butanol can reach 99.9wt.%, which is much higher than the level of existing technology, thereby improving the use value of the product.

[0022] 3. Simplified process: The utility model adopts specially connected dehydration device, hydrogenation reactor, gas-liquid separation tank and butanol refining tower and other equipment, and realizes efficient purification of butanol through a series of physical and chemical processes, simplifies the production process and reduces production costs.

[0023] 4. Environmental protection and safety: During the processing process, the utility model can also effectively recycle and utilize hydrogen, avoiding environmental pollution and ensuring the safety of the production process.

[0024] 5. Strong adaptability: The utility model is not only suitable for the purification of crude n-butanol produced as a by-product of the BDO process of the acetylene aldehyde method, but is also suitable for the purification of crude n-butanol from other sources. It has strong adaptability and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The disclosure of the present invention will become more easily understood with reference to the accompanying drawings. Those skilled in the art will readily appreciate that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Furthermore, similar numbers in the figures represent similar components, where:

[0026] Figure 1 1 is a schematic diagram of the main structure of a crude n-butanol purification system according to one embodiment of the present invention;

[0027] Figure 2 1 is a schematic diagram of the main structure of a crude n-butanol purification system according to Comparative Example 1 of the present utility model;

[0028] Figure 3 It is a schematic diagram of the main structure of the crude n-butanol purification system according to Comparative Example 2 of the present invention.

[0029] Reference Signs List :

[0030] 1 membrane module, 2 hydrogenation reactor, 2-1 hydrogen delivery pipe, 2-2 reactor input pipe, 2-3 reactor input pipe, 3 distillation tower, 4 permeate collection tank, 5 condensate collection tank, 6 gas-liquid separation tank, 6-1 separation tank delivery pipe, 7 distillation tank, 8 second preheater, 9 evaporator superheater, 10 jet pump condenser, 11 first preheater, 12 first condenser, 13 reboiler, 14 top condenser, 14-1 first liquid outlet, 14-2 second liquid outlet, 15 full condenser, 16 n-butanol cooler, 17 bottom liquid cooler, 18 second condenser, 19 filter, 20 steam jet vacuum pump, 21 material delivery pump, 22 bottom liquid delivery Pump, 23 distillate delivery pump, 24 n-butanol purified liquid delivery pump; 25-alcohol tower, 26-butanol tower, 27-butanol chromatograph, 28-alcohol tower reflux tank, 29-butanol chromatograph feed tank, 30-butanol tower reflux tank, 31-alcohol tower reboiler, 32-alcohol tower top condenser, 33-alcohol tower mid-production condenser, 34-alcohol tower kettle cooler, 35-butanol cooler, 36-butanol tower reboiler, 37-butanol tower top condenser, 38-butanol tower kettle cooler, 39-alcohol tower reflux pump, 40-alcohol tower kettle liquid delivery pump, 41-chromatograph feed pump, 42-butanol tower reflux pump, 43-butanol tower kettle liquid delivery pump; 44-decolorization column. DETAILED DESCRIPTION

[0031] Some embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0032] Reference Figure 1 The utility model provides a crude n-butanol purification system, which includes: a dehydration device, a first preheater 11, a hydrogenation reactor 2, a gas-liquid separation tank 6 and a distillation tower 3 connected in sequence.

[0033] The dehydration device includes a plurality of membrane modules 1 connected in sequence, with the modules 1 connected end to end. The number of membrane modules 1 is n, where n is a natural number satisfying 2≤n≤5. The bottom of each membrane module 1 is connected to a permeate collection tank 4. The membrane flux of the membrane modules 1 decreases in sequence.

[0034] The upper portion of the hydrogenation reactor 2 is connected to a hydrogen delivery pipe 2-1, the top of the hydrogenation reactor 2 is connected to a reactor input pipe 2-2 for connecting to the first preheater 11, and the bottom of the hydrogenation reactor 2 is connected to a reactor output pipe 2-3 for connecting to the gas-liquid separation tank 6;

[0035] The top of the gas-liquid separation tank 6 is connected to the first condenser 12 , and the bottom of the gas-liquid separation tank 6 is provided with a separation tank delivery pipe 6 - 1 for connecting to the middle of the distillation tower 3 .

[0036] A top condenser 14 is provided at the top of the distillation tower 3 , and a heating device is connected to the bottom of the distillation tower 3 .

[0037] When the utility model system is used, the working process includes:

[0038] S1: The crude n-butanol to be purified is fed into a dehydration device and dehydrated via membrane separation 1 to obtain a first mixture. The present invention processes the crude n-butanol to be purified by first dehydrating it. A permeate collection tank 4 is used to collect the dehydrated water.

[0039] S2: After being preheated in a first preheater 11, the first mixture is introduced into a hydrogenation reactor 2 via a reactor inlet pipe 2-2. Since the hydrogenation reactor 2 is loaded with a catalyst, a Pd / C catalyst is used. Thus, under the action of the Pd / C catalyst and with hydrogen being delivered to the hydrogenation reactor 2 via the hydrogen delivery pipe 2-1, the hydrogenation reactor 2 undergoes a catalytic hydrogenation reaction to produce a second mixture. The Pd / C catalyst is prepared in advance.

[0040] S3, the second mixture is fed into the gas-liquid separation tank 6 through the reactor output pipe 2-3 for gas-liquid separation. The second mixture is flash evaporated under reduced pressure in the gas-liquid separation tank 6 to obtain a third mixture.

[0041] S4, distilling the third mixture in a distillation tower 3 to obtain purified n-butanol.

[0042] The treatment object of the present invention is crude n-butanol, which includes n-butanol and impurities to be removed during the purification process, such as unsaturated substances such as propanol, methanol, aldehydes, and water.

[0043] In one embodiment, the crude n-butanol to be purified has a low n-butanol concentration, for example, a mass fraction of 1% to 10%. This utility model demonstrates significant advantages and broad application prospects in purifying low-concentration n-butanol. It not only overcomes the high energy consumption, complex processes, and high investment associated with traditional purification methods, but also achieves a highly efficient, low-energy, and low-investment purification process through specialized equipment configurations.

[0044] In one embodiment, the system further includes: a material delivery pump 21 and a second preheater 8; wherein, the material delivery pump 21 is used to deliver crude n-butanol to be purified, the material delivery pump 21 is connected to one end of the second preheater 8, and the other end of the second preheater 8 is connected to the dehydration device.

[0045] The concentrated butanol solution is discharged from the other side of the membrane assembly 1, and after being preheated by the second preheater 8 and condensed by the second condenser 18, the concentrated butanol solution is sent to the first preheater 11 at a pressure of 0.8 MPa, and is preheated to a temperature of 120°C and sent to the hydrogenation reactor 2.

[0046] The crude butanol to be purified is heated by the first preheater 11 and the second preheater 8 to ensure that the crude butanol is fed into the hydrogenation reactor 2 at the reaction temperature and that the crude butanol can start to react as soon as it contacts the catalyst, thereby preparing for the subsequent hydrogenation reaction.

[0047] In one embodiment, the dehydration device comprises n gradient flux membrane modules 1 connected in sequence.

[0048] In one embodiment, the system further comprises: an evaporator superheater 9 and a second condenser 18; the dehydration device comprises a first membrane assembly 1-1, a second membrane assembly 1-2, a third membrane assembly 1-3, a fourth membrane assembly 1-4 and a fifth membrane assembly 1-5 connected in sequence.

[0049] One end of the evaporator superheater 9 is connected to the second preheater 8, the other end of the evaporator superheater 9 is connected to the liquid inlet of the first membrane assembly 1-1, and the liquid outlet of the fifth membrane assembly 1-5 is connected to the second preheater 8, the second condenser 18 and the first preheater 11 in sequence.

[0050] When in use, the crude n-butanol to be purified is heated by the material delivery pump 21 through the second preheater 8 and the evaporator superheater 9 to 60°C, and then input into the 5-stage membrane assembly 1 to concentrate the crude n-butanol and improve the dehydration effect. The membrane assembly 1 includes a molecular sieve membrane with a separation factor of 20-80 and a permeation flux of 200-2000g / (m 2 ·□hr). The membrane flux of the five membrane modules decreases in sequence, that is, dehydration is carried out in sequence from coarse to fine, which can improve the efficiency and accuracy of dehydration.

[0051] In one embodiment, the reactor output pipe 2-3 is further connected to a filter 19. The filter 19 is a catalyst filter, and the catalyst comes from the hydrogenation reactor 2.

[0052] The liquid phase at the bottom of hydrogenation reactor 2 is the second mixture after regulating valve decompression such as being decompressed to 0.6MPa, is filtered by strainer 19, the filter membrane pore size in strainer 19 being 0.2 μm, thereby removing catalyst powder, then inputting in knockout drum 6 flash separation hydrogen.This processing mode can effectively remove catalyst powder, improves the purity of butanols.The first condenser 12 at knockout drum 6 top is the first condenser, and the condensate in the first condenser 12 returns to knockout drum 6, and uncondensed gas phase is discharged to tail gas line and is processed, to ensure hydrogen purity.And the butanols carried secretly in the gas phase can be effectively recovered, improve product yield.

[0053] After the hydrogen dissolved in the second mixture is flash-evaporated and separated in the gas-liquid separation tank 6, the liquid phase obtained is the third mixture, which is transported to the butanol refining tower, i.e., the distillation tower 3, for further treatment.

[0054] In one embodiment, a reboiler 13 is connected to the bottom of the distillation tower 3. The reboiler 13 serves as a heating device for the distillation tower 3. Heat for the distillation tower 3 is provided by the reboiler 13 using 0.8 MPG saturated steam at an operating pressure of 0.6 MPa. The heating temperature of the distillation tower 3 is 150°C. The distillation tower kettle is subjected to distillation at 110 kPa, and the reflux ratio of the overhead reflux liquid is 40.

[0055] In one embodiment, the system further includes: a full condenser 15, a distillate tank 7 and a distillate delivery pump 23; wherein, the top condenser 14 includes a first liquid outlet 14-1 and a second liquid outlet 14-2, the first liquid outlet 14-1 is connected to the distillate tank 7, the second liquid outlet 14-2 is connected to the full condenser 15, the liquid outlet of the full condenser 15 is connected to the liquid inlet of the distillate tank 7, the liquid outlet of the distillate tank 7 is connected to the liquid inlet of the distillate delivery pump 23, and the liquid outlet of the distillate delivery pump 23 is connected to the top of the distillation tower 3.

[0056] The liquid cooled by the total condenser 15 is collected in the distillation tank 7, and the uncondensed gas phase is discharged.

[0057] The distillate delivery pump 23 refluxes the liquid collected in the distillation tank 7 to the top of the distillation tower 3 .

[0058] In one embodiment, the system further includes: an n-butanol purified liquid delivery pump 24 and an n-butanol cooler 35; wherein one end of the n-butanol purified liquid delivery pump 24 is connected to the middle or upper part of the distillation tower 3, and the other end of the n-butanol purified liquid delivery pump 24 is connected to the n-butanol cooler 16.

[0059] The purified n-butanol product is extracted from the distillation tower 3 by the n-butanol purified liquid delivery pump 24, cooled to 60° C. by the n-butanol cooler 35, and delivered to the purified product storage tank.

[0060] In one embodiment, the system of the present invention further includes: a steam jet vacuum pump 20 , a jet pump condenser 10 and a condensate collection tank 5 .

[0061] The permeate collection tank 4, the steam jet vacuum pump 20, the jet pump condenser 10 and the condensate collection tank are connected in sequence.

[0062] The permeate collection tank 4 is evacuated by a steam jet vacuum pump 20, and the exhaust gas and steam are mixed and condensed by the jet pump condenser 10. The gas phase is discharged and the liquid phase is collected in the condensate collection tank 5 and discharged to be reused as industrial water.

[0063] In one embodiment, the system further includes: a bottom liquid delivery pump 22 and a bottom liquid cooler 17; wherein the liquid inlet of the bottom liquid delivery pump 22 is connected to the bottom of the distillation tower 3, and the bottom liquid cooler 17 is connected to the liquid outlet of the bottom liquid delivery pump 22.

[0064] After purification by the system of the present invention, the bottom liquid in the distillation tower 3 mainly contains n-butanol and heavy components. The heavy components are sent out by the bottom liquid delivery pump 22 connected to the bottom of the distillation tower 3, cooled to 60°C by the bottom liquid cooler 17, and the liquid phase containing the heavy components is sent out for external treatment.

[0065] In one embodiment, the crude n-butanol to be purified is a by-product of the preparation of 1,4-butanediol, and the n-butanol content in the n-butanol solution produced as a by-product of the acetylene-aldehyde BDO process is 1% to 10%.

[0066] In one embodiment, the components of crude n-butanol as a by-product of preparing 1,4-butanediol include:

[0067] n-Butanol 3.07 wt.%;

[0068] Methanol 0.28 wt.%;

[0069] Propanol 0.05wt.%;

[0070] Water 96.42%;

[0071] Butyraldehyde 0.06%;

[0072] The heavy component is 0.12%.

[0073] This utility model's purification system effectively purifies crude n-butanol, a byproduct of the acetylene-aldehyde process for producing 1,4-butanediol. While using low energy, it effectively removes various impurities from the crude n-butanol, including unsaturated compounds such as propanol, methanol, and aldehydes, thereby increasing the purity of the butanol. Furthermore, it effectively reduces the color and odor of the butanol, improving the user experience and safety of the n-butanol.

[0074] As a major producer of BDO (1,4-butanediol) and the largest producer of the acetylene-aldehyde process, my country places great importance on the effective purification of byproducts from the acetylene-aldehyde process. The n-butanol extracted through this process is a widely used basic organic chemical raw material used in the manufacture of various chemicals.

[0075] The following is a detailed description of the various steps for the purification of crude n-butanol, see Figure 1 .

[0076] Explanation of Step S1

[0077] The utility model first dehydrates the crude solution, feeding it to a dehydration device. The dehydration device incorporates one or more dehydration membranes, which separate the solvent from water, thereby improving the solvent's purity. These membranes possess excellent solvent permselectivity and water-rejection properties, enabling precise separation of solvent and water molecules under mild operating conditions. After dehydration in step S1, the mass fraction of water in the first mixture is ≤10%.

[0078] Membrane separation technology allows for efficient dehydration of the crude solution (crude n-butanol), removing most impurities and water from the crude n-butanol and paving the way for subsequent purification steps. This step not only improves purification efficiency but also reduces the burden on subsequent processes.

[0079] In one embodiment, before the crude n-butanol to be purified is fed into the dehydration device, the method further comprises:

[0080] The crude n-butanol to be purified is heated to 50-80°C in the second preheater.

[0081] In an application scenario, refer to Figure 1The crude n-butanol to be purified is pumped by material delivery pump 21 at a pressure of 0.8 MPa into second preheater 8 and evaporator superheater 9, where it is preheated with saturated steam at 150°C. After the crude n-butanol is heated to 120°C, it is then fed into the dehydration unit. This preheating method effectively raises the temperature of the butanol, preparing it for the subsequent decolorization reaction.

[0082] In order to improve the effect and efficiency of dehydration, dehydration is performed in stages and multiple times according to the water content. In one embodiment, the crude n-butanol to be purified is fed into a dehydration device and dehydrated by membrane separation to obtain the first mixture, which comprises:

[0083] The dehydration device comprises n gradient flux membrane modules 1 connected in sequence, and the crude n-butanol to be purified passes through each of the membrane modules 1 in sequence for dehydration, wherein the feed temperature of the crude n-butanol to be purified in each membrane module is 50-80° C. and the pressure is 0.1-5 kPaA;

[0084] After dehydration through the n membrane modules 1, a first mixture is obtained, wherein the mass fraction of water in the first mixture is ≤10%.

[0085] In one embodiment, the membrane fluxes of the n membrane modules 1 decrease in sequence.

[0086] In one embodiment, the present invention uses molecular sieve membrane separation for dehydration and concentration. The membrane assembly 1 includes a molecular sieve membrane, which uses the strong adsorption of water molecules by the molecular sieve membrane to achieve the purpose of deep dehydration. The molecular sieve membrane dehydration has many advantages such as high efficiency, energy saving, and no environmental pollution. The separation factor of the molecular sieve membrane is 20-80, and the permeation flux is 200-2000g / (m 2 ·□hr).

[0087] In an application scenario, still refer to Figure 1 Taking n=5 as an example, the crude n-butanol to be purified is preheated and then fed into a five-stage membrane module 1 to concentrate the n-butanol aqueous solution. Each membrane module 1 is a dehydration tank equipped with a molecular sieve membrane for dehydration. The five membrane modules 1 are connected in sequence. After the crude n-butanol is dehydrated from the previous membrane module 1, the concentrate enters the next membrane module 1 for further concentration and water removal. After five dehydration cycles, the final membrane module 1 dehydrates the crude n-butanol and then enters the second preheater 8 for heating.

[0088] The bottom of each membrane module 1 is connected to a permeate collection tank 4. Water is separated by the membranes of each membrane module 1, enters the permeate collection tank 4 from the bottom of the membrane module 1, and is discharged outside.

[0089] Explanation of Step S2

[0090] 1. Preheat

[0091] The concentrated liquid after dehydration by the membrane module 1 of the dehydration device is recorded as the first mixture, which is input into the first preheater 11 for preheating. The first mixture is heated to 100-150° C., preferably 110-130° C. in the first preheater 11. After preheating, the first mixture is input into the hydrogenation reactor 2.

[0092] 2. Hydrogenation catalytic reaction

[0093] Dehydrated crude n-butanol (dehydrated crude n-butanol) and hydrogen are fed from the top of the hydrogenation reactor 2.

[0094] The catalyst for the catalytic hydrogenation reaction is a Pd / C catalyst. The Pd / C catalyst is a catalyst made of palladium (Pd) metal supported on a carbon (C) material.

[0095] In one embodiment, the Pd / C catalyst is further doped with a metal element M, wherein the metal element M is one or more selected from transition metal elements (excluding lanthanides and actinides), preferably at least one of nickel, chromium, molybdenum, silver, and copper; the mass ratio of the doping amount of the metal element M to Pd is (0.01-1):1, preferably (0.05-0.5):1, and the doping amount of the metal element M does not exceed the loading amount of Pd.

[0096] In the present embodiment, a catalyst using activated carbon as a carrier is employed. Specifically, a compound containing palladium metal is loaded on an activated carbon carrier. In order to further optimize the performance of the catalyst, a second metal element, i.e., metal element M, is also introduced on the activated carbon for modification. The purpose of this modification is to reduce the loading of palladium metal, thereby forming a novel (Pd-M) / C catalyst, which is achieved by loading metal palladium (Pd) and another metal element M on a carbon carrier (C). In this way, not only can the use of precious metals be significantly reduced, thereby effectively reducing the manufacturing cost of the catalyst, but also the overall activity and stability of the catalyst can be significantly improved. There is a certain synergistic effect between metal palladium (Pd) and metal element M, and this synergistic effect can still efficiently complete the target of hydrogenation reaction under the condition that the loading of precious metal palladium is low. In this way, not only the efficiency of catalytic hydrogenation is improved, but also the effect of catalytic hydrogenation is further enhanced, making the whole reaction process more economical and efficient.

[0097] In the (Pd-M) / C catalyst, the mass fraction of the Pd element is 0.1-5 wt%, more preferably 0.1-2%.

[0098] The space-time yield (STY) of the catalyst is 20 to 60 mg / g·h -1 .

[0099] In one embodiment, the metal element M is Ni.

[0100] The (Pd-M) / C catalyst is preferably prepared using an isovolumetric impregnation method. First, a commercial activated carbon support is purchased and then dried at 100-150°C for 12-24 hours. After drying, the activated carbon support is cooled to room temperature for subsequent use.

[0101] Next, the prepared Pd source and the second metal source (metal element M doping source) are impregnated onto the activated carbon support by the impregnation method. Specifically, the Pd source and the second metal source (metal element M doping source) are mixed evenly to form a mixed solution. The activated carbon support and the mixed solution are fully stirred into a suspension, and then impregnated. During the impregnation process, it is necessary to stand for 2-4 hours to ensure that the Pd and the second metal (metal element M) can fully penetrate into the activated carbon support. After standing, the impregnated activated carbon support is dried at 120°C.

[0102] After drying, the impregnated activated carbon was placed in a calciner and calcined at 550°C for 24-48 hours. After calcination, the catalyst was cooled to room temperature and then loaded into a reactor for use.

[0103] When selecting a Pd source, a Pd salt solution is preferably used, such as PdCl2. As a Pd source, a metal element M doping source (second metal source) is preferably a metal element M salt solution, such as Ni source, such as Ni(NO3)2·□6H2O. When selecting an activated carbon support, its diameter is preferably 0.5-5 mm, and the specific surface area of ​​the carbon support is preferably ≥200 m 2 / g, and the pore volume of the carrier is preferably 0.30-0.80cm 3 Through the above steps, a (Pd-M) / C catalyst with excellent performance can be prepared.

[0104] Liquid-phase hydrogenation reaction under the action of (Pd-M) / C catalyst can effectively eliminate the coloring functional groups.

[0105] In one embodiment, the catalytic hydrogenation reaction 2 is carried out in a fixed bed reactor, preferably a trickle bed reactor. In one embodiment, the reaction pressure of the catalytic hydrogenation reaction is 2-3 MPa, the reaction temperature is 100-150° C., the reaction time is 1-3 hours, and the feed molar ratio of hydrogen to the first mixture is 1:200.

[0106] In one application scenario, in hydrogenation reactor 2, crude n-butanol reacts with catalyst Pd / (Ni-C), where the catalyst particles have a diameter of 0.5 mm. The two are in full contact, and a hydrogenation reaction occurs on the catalyst surface. The reaction temperature is 120°C and the reaction time is 2 hours. The unsaturated organic matter contained in the crude n-butanol is hydrogenated to eliminate the effect of the unsaturated organic matter on the color of the butanol.

[0107] This hydrogenation reaction can effectively eliminate the unsaturated bonds in butanol and reduce the color and odor of butanol.

[0108] Explanation of Step S3

[0109] After catalytic hydrogenation in hydrogenation reactor 2, a second mixture is obtained. Its primary components are n-butanol, water, propanol, and heavy components, along with a trace amount of unreacted hydrogen. Hydrogen is continuously discharged below the packing section of hydrogenation reactor 2 and then flashed under reduced pressure in separator tank 6 to remove dissolved hydrogen from the liquid phase.

[0110] The process of reduced pressure flash evaporation is as follows: the second mixture is input into the gas-liquid separation tank 6 for reduced pressure flash evaporation, wherein during the reduced pressure flash evaporation, the pressure of the gas-liquid separation tank 6 is controlled to be 0.4-0.6 MPa to perform flash evaporation to separate the dissolved gas.

[0111] The condensation temperature of the first condenser 12 on the top of the gas-liquid separation tank 6 is set to ≤40° C., and the entrained organic matter is removed before discharge.

[0112] Explanation of Step S4

[0113] In one embodiment, the distilling the third mixture in the distillation tower 3 to obtain purified n-butanol comprises:

[0114] After the reduced pressure flash evaporation, the liquid phase in the gas-liquid separation tank 6, i.e., the third mixture, is pressed into the distillation tower 3 by the pressure of the gas-liquid separation tank 6 for distillation;

[0115] The reflux ratio of the top reflux liquid of the distillation tower 3 is 30-50, and the distillation tower kettle is subjected to distillation at 101-120 kPa.

[0116] The liquid in the middle and / or upper part of the bottom of the distillation tower 3 is collected to obtain purified n-butanol.

[0117] In an application scenario, still refer to Figure 1 The distillation tower 3 is a 5-stage packed tower. The third mixture is finally purified by the butanol refining tower, i.e., the distillation tower 3. The light components are removed from the top of the distillation tower 3, the heavy components are extracted from the bottom of the distillation tower 3, and the n-butanol product is extracted from the distillation tower.

[0118] During distillation, the bottom temperature of distillation tower 3 is between 110°C and 150°C, with heat provided by a reboiler 13 connected to the bottom of the bottom of distillation tower 3. The top of distillation tower 3, primarily composed of butanol, water, and a trace amount of light propanol solution, is condensed by an overhead condenser 14 at 40°C. The condensate is collected in a distillate tank 7 and returned to the bottom of the tower by a distillate pump 23. Alternatively, a portion of the condensate can be sent to the butanol chromatograph in the BDO distillation unit for further water treatment. The light components from the top of the tower can also be recycled upstream. The bottom liquid primarily contains n-butanol and heavy components. The heavy components are discharged by a bottom liquid pump 22 connected to the bottom of distillation tower 3, cooled to 60°C by a bottom liquid cooler 17, and the liquid phase containing the heavy components is then sent to an external facility for further processing.

[0119] Qualified n-butanol product is withdrawn from distillation tower 3 by n-butanol purified liquid delivery pump 24, cooled to 60°C in n-butanol cooler 16, and then delivered to a storage tank. n-butanol purified liquid delivery pump 24 is used to collect the liquid phase from the middle and / or upper portion of distillation tower 3, specifically the area below the top of distillation tower 3 and the middle and upper portions thereof.

[0120] This utility model utilizes a specific purification system, ultimately requiring only a single distillation column for purification, effectively improving the purity of butanol. After treatment with this purification system, the n-butanol product reaches a purity of 99.9 wt.%, with a color number within 10 (Hazen units), exceeding the requirements of Type I of GB / T 6027-2023, "Industrial n-Butanol." It also exhibits improved performance in the sulfuric acid color development test, reaching within 20. This purification method effectively improves the quality of n-butanol and meets the needs of industrial production.

[0121] This utility model provides a system for processing crude n-butanol, a byproduct of BDO. Membrane separation and dehydration are performed in a dehydration unit to increase the concentration to above 99.6%. Impurities in the crude butanol are simultaneously hydrogenated in a hydrogenation reactor 2, achieving a sulfuric acid colorimetric test value of below 20. Finally, primary distillation in a distillation tower 3 removes light and heavy components such as fusel alcohols. After secondary distillation, the resulting n-butanol product meets the requirements of the national standard GB / T 6027-2023 Type I. This purification system offers the advantages of low energy consumption, a simple process, and high product quality. my country is a major BDO producer. Given the increasingly fierce competition in the BDO industry, this utility model is of great significance in reducing production costs, alleviating environmental pressures, and improving economic efficiency.

[0122] As an important chemical raw material, n-butanol plays a crucial role in the production of many products. In the cosmetics industry, in particular, the color of n-butanol directly impacts the quality of the final product. For example, n-butanol is often used as a solvent in cosmetics production, particularly in products like nail polish, where it serves as a cosolvent in combination with primary solvents such as ethyl acetate. This combination aids in the dissolution of pigments while also regulating the solvent's evaporation rate and viscosity, thereby ensuring product stability and effectiveness.

[0123] The system of this utility model can produce high-purity n-butanol, and its color number is significantly reduced through the efficient decolorization process of multiple membrane modules. This significantly improves the quality of products used as solvents for products with extremely high color requirements, such as cosmetics. The high purity and low color number of n-butanol not only enhances product color but also ensures product safety and stability, thus meeting consumer demand for high-quality cosmetics.

[0124] n-Butanol is also widely used in the production of screen printing inks. It serves as a defoaming agent during the ink mixing process, enabling more precise ink blending. By using n-butanol that has undergone efficient decolorization treatment using multiple membrane modules, ink uniformity and stability can be ensured, thereby guaranteeing the quality of the final product. In fine printing applications like screen printing, the use of n-butanol can significantly enhance printing results, ensuring image clarity and color saturation.

[0125] n-Butanol also plays a vital role in the fragrance and flavor industry. It serves not only as a solvent but also as a diluent, helping to adjust the concentration and uniformity of fragrances. The high-quality n-butanol produced by this utility model can better leverage its potential in the fragrance production process, thereby enhancing the quality of fragrances. The excellent properties of n-butanol make fragrances more stable during blending, resulting in a more lasting and natural fragrance, thus satisfying the market demand for high-quality fragrances.

[0126] In summary, the high-efficiency decolorization system described in this utility model not only improves the quality of n-butanol but also has broad application value and promotional significance. This technology can provide higher-standard raw materials for various industries, such as cosmetics, inks, and fragrances, thereby promoting the development of related industries and meeting consumer demand for high-quality products.

[0127] The steam jet vacuum pump 20 evacuates the permeate collection tank 4. The gas phase in the permeate collection tank 4 is mixed with steam and condensed in the jet pump condenser 10. The gas phase is then discharged and the liquid phase can be reused as industrial water.

[0128] The system of this utility model effectively reduces the color and odor of butanol through multi-stage dehydration in a dehydration unit, hydrogenation in a hydrogenation reactor 2, gas-liquid separation in a gas-liquid separator 6, and distillation purification in a distillation tower 3, thereby improving the user experience and safety of n-butanol. Simultaneously, various impurities in butanol, including unsaturated compounds such as propanol, methanol, and aldehydes, are effectively removed with low energy consumption, thereby improving the purity of n-butanol.

[0129] The purification effect of the utility model is described below in conjunction with the examples and comparative examples.

[0130] Example 1

[0131] Treatment of crude n-butanol produced as a byproduct of a BDO unit using the acetylene-aldehyde process. The components of the crude n-butanol to be purified are shown in Table 1. The flow rate is 200 kg / h.

[0132] Table 1 Material composition of the input device of Example 1

[0133] project unit index Appearance —— Light yellow transparent liquid with pungent odor Color Hazen Unit 30 purity wt.% 3.07％ Water content wt.% 96.42％ Methanol content wt.% 0.28％ Propanol content wt.% 0.05％ Butyraldehyde wt.% 0.06％ Heavy component content wt.% 0.12％

[0134] S1, the crude n-butanol of the content in Table 1 is heated by the material delivery pump 21 through the second preheater 8 and the evaporator superheater 9 to 60 ° C, and then input into the 5-stage membrane module 1 to concentrate the crude n-butanol. The membrane module 1 includes a molecular sieve membrane, the separation factor of the molecular sieve membrane is 20-80, and the permeation flux is 200-2000g / (m 2 The feed pressure of the crude n-butanol to be purified in each membrane module is 0.1-5 kPaA.

[0135] After concentration, a first mixture is obtained, and the water removed by concentration enters the permeate collection tank 4 from the bottom of the membrane module 1 and is discharged outside.

[0136] S2, the first mixture obtained after concentration is discharged from the output end of the dehydration device, condensed by the preheater 8 and the second condenser 18, and then sent to the first preheater 11 at a pressure of 0.8 MPa, and is preheated to a temperature of 120°C and sent to the hydrogenation reactor 2.

[0137] In the hydrogenation reactor 2, a (Pd-Ni) / C catalyst (Pd content of 0.3 wt%) was prepared in advance. The preparation method of the (Pd-Ni) / C catalyst is as follows:

[0138] Palladium chloride (PdCl2) was fully dissolved in concentrated hydrochloric acid according to the loading amount, and stirred thoroughly. Ni(NO3)2·□6H2O was then added at a mass ratio of Ni:Pd elements of 0.5:1 to prepare a mixed solution.

[0139] The commercially available pre-treated carbon carrier (Japan OGC, C2X granular activated carbon carrier, diameter 3mm, specific surface area 810m 2 / g) weigh 3.43 kg for pretreatment, mix with the mixed solution, stir thoroughly to form a suspension, and stir at a constant temperature of 60°C for 6 hours. After adding 0.1 mol / L sodium hydroxide to the impregnated catalyst, add formaldehyde dropwise, stir continuously to adjust the pH value, let it stand for 2 hours, and cool to room temperature. Wash with distilled water until the conductivity is less than 10 (us / cm), and dry at 110°C for 8 hours. The impregnated catalyst is placed in a calcination furnace and calcined at a temperature of 550°C for 24 hours. After the calcination is completed, cool to room temperature, and the space-time yield of the obtained catalyst is in the range of 20 to 60 mg / g·□h -1 , and add the obtained catalyst into hydrogenation reactor 2.

[0140] A catalytic hydrogenation reaction was carried out in the hydrogenation reactor 2 filled with the above-mentioned catalyst. The extract to be extracted output from the first preheater 11 was fully contacted with the catalyst ((Pd-Ni) / C catalyst, catalyst particle diameter was 3 mm). The molar ratio of hydrogen to the first mixture was 1:200. A hydrogenation reaction occurred on the catalyst surface. The reaction temperature was 120° C., the reaction pressure of the catalytic hydrogenation reaction was 2.5 MPa, and the reaction time was 2 hours. After the reaction, a second mixture was obtained.

[0141] In step S3, the liquid phase at the bottom of hydrogenation reactor 2 is depressurized to 0.6 MPa via a regulating valve, and the hydrogen dissolved in the liquid is separated. The liquid, or second mixture, is then passed through filter 19 to remove catalyst powder and fed to separator tank 6 for flash evaporation under reduced pressure. The condensation temperature at the top of separator tank 6 is set to 40°C, and the separator tank pressure is maintained at 0.6 MPa. The condensate is then condensed in first condenser 12 at the top of separator tank 6, and the condensate is returned to separator tank 6. The uncondensed gas phase is discharged to the tail gas pipeline for disposal.

[0142] After the reduced pressure flash evaporation, the third mixture is output from the bottom of the gas-liquid separation tank 6 .

[0143] S4: The third mixture is fed into distillation tower 3, a five-stage packed tower. The mixture is condensed in overhead condenser 14 at a temperature of 40°C. The condensate is collected in distillate tank 7 and partially refluxed to the bottom of the tower by distillate transfer pump 23. Heat for distillation tower 3 is provided by reboiler 13 using 0.8 MPG saturated steam. The operating pressure is 0.6 MPa, and the heating temperature of distillation tower 3 is 150°C. Distillation is performed in the bottom of the distillation tower at 110 kPa, and the reflux ratio of the overhead reflux liquid is 40.

[0144] The purified n-butanol product is taken out from the distillation tower 3 by the n-butanol purified liquid delivery pump 24, cooled to 60° C. by the n-butanol cooler 16, and then delivered to the storage tank.

[0145] The purified n-butanol product in the storage tank described in Example 1 was tested, and the test results are shown in Table 2.

[0146] Table 2 Test results of n-butanol product obtained in Example 1

[0147]

[0148] Comparative Example 1

[0149] According to the attached Figure 2 The extraction system processes the crude butanol. The feed conditions are the same as those in Example 1. This comparative example uses a distillation method to purify the crude butanol. The purification process includes:

[0150] Step 1: Crude n-butanol is first fed into the first distillation tower (alcohol tower 25) for rectification. Operating at a pressure of 101-103 kPa, an operating temperature of 90-110°C, and a reflux ratio of 11, the first distillation tower removes the light fusel alcohol components. Fusel alcohols, including methanol, propanol, butanol, water, and other light components, are condensed to 60°C in the first overhead condenser (alcohol tower overhead condenser 32) and collected in the first reflux tank (alcohol tower reflux tank 28). A portion is refluxed to the top of the tower by the first reflux pump (alcohol tower reflux pump 39), while a portion is withdrawn for off-site processing. This bottoms process water is withdrawn by the first bottoms transfer pump (alcohol tower bottoms transfer pump 40), cooled to 40°C by the first bottoms cooler (alcohol tower bottoms cooler 34), and then reused. The intermediate production is hydrous n-butanol (water content ≤10%). After condensing to 75°C in the intermediate production condenser (alcohol tower), it is collected in the chromatograph feed tank 29.

[0151] Step 2: The aqueous n-butanol in chromatograph feed tank 29 is further delivered to butanol cooler 35 by chromatograph feed pump 41, cooled to below 40°C, and then fed into butanol chromatograph 27. Water and butanol are immiscible in butanol chromatograph 27 and separate into separate layers. The upper layer, butanol, is delivered to the second distillation tower, butanol tower 26; the lower layer, water, returns to alcohol tower 25 for further dehydration.

[0152] Step 3: The second distillation tower, i.e., the butanol tower 26, operates at a pressure of 105-110 kPa, an operating temperature of 95-120°C, and a reflux ratio of 1. The butanol at the top of the tower, which has a high water content, is condensed to 75°C by the second overhead condenser, i.e., the butanol tower overhead condenser 37. The butanol is then collected in the second reflux tank, i.e., the butanol tower reflux tank 30. A second reflux pump, i.e., the butanol tower reflux pump 42, partially refluxes to the top of the tower, and a portion is sent to the chromatograph feed tank 29 for further separation of butanol and water. The bottom of the second distillation tower 26 is the n-butanol product, which is extracted by the second bottom liquid delivery pump, i.e., the butanol tower bottom liquid delivery pump 43. After being cooled to 40°C by the second bottom cooler 38, it is sent to the product storage tank.

[0153] Comparative Example 2

[0154] According to the attached Figure 3 The extraction system processes the crude butanol. The feed conditions are the same as those in Example 1. This comparative example uses a distillation method to purify the crude butanol. The purification process differs from that in Comparative Example 1 in that:

[0155] After the butanol product in the second distillation tower, i.e., the butanol tower 26, is cooled, the color problem of the butanol is treated by adding resin physical adsorption.

[0156] The decolorizing column 44 is specifically a resin decolorizing column, which is equipped with a general macroporous adsorption resin and is not particularly limited. The butanol product passing through the resin decolorizing column 44 is sent to a storage tank.

[0157] The butanol products in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 were analyzed respectively, and the component contents of butyraldehyde therein were compared. The analysis results are shown in Table 1:

[0158] Table 3 Experimental data of Example 1 and Comparative Examples 1-2

[0159]

[0160]

[0161] From the results of the above comparative analysis, it can be seen that the system of the present invention can be used for efficient purification, which not only effectively reduces the color of the product but also reduces the content of impurities, especially butyraldehyde, and the complexity and cost of the system of the present invention are lower than those of the comparative purification system.

[0162] The n-butanol products in Example 1, Comparative Example 1 and Comparative Example 2 were analyzed respectively. The analysis results are shown in Table 4 below.

[0163] Table 4 Test results of n-butanol products obtained in Examples and Comparative Examples

[0164]

[0165] From the comparison of the above analysis results, it can be seen that although the concentration of n-butanol in the comparative example has exceeded the national standard requirements through distillation, the chromaticity cannot be effectively reduced by distillation. The indicators of the sulfuric acid color development test cannot be removed by physical adsorption methods such as resin adsorption, and the coloring functional groups cannot be removed, and it still cannot appear as a qualified national standard product.

[0166] The product that has not been processed through the crude n-butanol purification system of the present invention is inferior to the product that has been processed through the crude n-butanol purification system of the present invention in terms of n-butanol content, water content, color number and heavy component content. By comparing the embodiment with comparative examples 1-2, it can be concluded that the color number and sulfuric acid color development test of the n-butanol product processed and purified by the system of the present invention are significantly better than the color number of the product processed by the conventional resin decolorization method.

[0167] The purity and detailed composition analysis of n-butanol were measured using an Agilent 7890 chromatograph.

[0168] Color number testing is in accordance with GB3143-1982, measured by Lovibond Tintometer PFX190.

[0169] The sulfuric acid color number test is carried out in accordance with the method in GB / T6027-2023, and the colorimetry is carried out in accordance with the provisions of GB / T3143-1982.

[0170] The carbonyl number is used to analyze the carbonyl functional group content in butanol. It is measured using the hydroxylamine hydrochloride titration method using a Mettler T90 titrator. The carbonyl compounds in the sample can react with hydroxylamine hydrochloride to generate H+. The H+ is titrated with a NaOH standard solution. The calculation of the measurement result is

[0171]

[0172] Where: SN——the number of carbonyl groups in the sample

[0173] V——Sample consumption of NaOH, ml

[0174] C——Concentration of NaOH standard solution, M

[0175] M——mass of sample, g.

[0176] It can be seen from the above experimental data that compared with the existing technology, the beneficial effects of this technical solution are as follows:

[0177] 1. Efficient decolorization: The decolorization reaction is carried out in the hydrogenation reactor, which can effectively eliminate the unsaturated bonds in butanol. This solves the problem that the crude butanol or waste butanol produced by the existing equipment is difficult to meet the color number required by the national standard and the two key indicators of the sulfuric acid color development test, thereby improving the quality of the product.

[0178] 2. High economic benefits: After purification by the utility model system, the purity of n-butanol can reach 99.9% at low cost without using a complex system. More importantly, the color number of butanol and the indicators of the sulfuric acid color development test meet the requirements of GB / T6027-2023 "Industrial n-butanol" Type I, which is much higher than the level of existing technology, thereby increasing the added value of the product.

[0179] 3. Simplified process: The utility model adopts a dehydration device, a hydrogenation reactor and a butanol refining tower with a specific connection relationship. Through a series of physical and chemical processes, it realizes the efficient purification of butanol, simplifies the production process and reduces production costs.

[0180] 4. Environmental protection and safety: During the processing process, the utility model effectively recovers and utilizes hydrogen through equipment such as the gas-liquid separation tank and the first condenser, avoiding environmental pollution while also ensuring the safety of the production process.

[0181] 5. Strong adaptability: The utility model is not only suitable for the purification of crude n-butanol produced as a by-product of the BDO process of the acetylene aldehyde method, but is also suitable for the purification of crude n-butanol from other sources. It has strong adaptability and broad application prospects.

[0182] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effect of the present invention, different steps do not have to be performed in such an order. They can be performed simultaneously (in parallel) or in other orders. These changes are within the scope of protection of the present invention.

[0183] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A crude n-butanol purification system, characterized in that: include: A dehydration device, a first preheater (11), a hydrogenation reactor (2), a gas-liquid separation tank (6), and a distillation tower (3) are connected in sequence; the dehydration device comprises a plurality of membrane modules (1) connected in sequence, the number of the membrane modules (1) being n, where n is a natural number and satisfies 2≤n≤5, and the bottom of each membrane module (1) is connected to a permeate collection tank (4); The upper portion of the hydrogenation reactor (2) is connected to a hydrogen delivery pipe (2-1), the top of the hydrogenation reactor (2) is connected to a reactor input pipe (2-2) for connecting to the first preheater (11), and the bottom of the hydrogenation reactor (2) is connected to a reactor output pipe (2-3) for connecting to a gas-liquid separation tank (6); The top of the gas-liquid separation tank (6) is connected to the first condenser (12), and the bottom of the gas-liquid separation tank (6) is provided with a separation tank delivery pipe (6-1) for connecting to the middle of the distillation tower (3); A top condenser (14) is provided at the top of the distillation tower (3), and a heating device is connected to the bottom of the distillation tower (3).

2. The system according to claim 1, wherein: The system further comprises: a material delivery pump (21) and a second preheater (8); wherein the material delivery pump (21) is used to deliver crude n-butanol to be purified, the material delivery pump (21) is connected to one end of the second preheater (8), and the other end of the second preheater (8) is connected to the dehydration device.

3. The system according to claim 2, characterized in that The system further comprises: an evaporator superheater (9) and a second condenser (18); the dehydration device comprises a first membrane assembly, a second membrane assembly, a third membrane assembly, a fourth membrane assembly and a fifth membrane assembly connected in sequence; One end of the evaporator superheater (9) is connected to the second preheater (8), the other end of the evaporator superheater (9) is connected to the liquid inlet of the first membrane assembly, and the liquid outlet of the fifth membrane assembly is connected to the second preheater (8), the second condenser (18) and the first preheater (11) in sequence.

4. The system according to claim 1, wherein: The reactor output pipe (2-3) is also connected to a filter (19).

5. The system according to claim 1, wherein: The bottom of the distillation tower (3) is connected to a reboiler (13).

6. The system according to claim 1, wherein: The system further comprises: a full condenser (15), a distillate tank (7) and a distillate delivery pump (23); wherein the tower top condenser (14) comprises a first liquid outlet (14-1) and a second liquid outlet (14-2), the first liquid outlet (14-1) being connected to the distillate tank (7), the second liquid outlet (14-2) being connected to the full condenser (15), the liquid outlet of the full condenser (15) being connected to the liquid inlet of the distillate tank (7), the liquid outlet of the distillate tank (7) being connected to the liquid inlet of the distillate delivery pump (23), and the liquid outlet of the distillate delivery pump (23) being connected to the tower top of the distillation tower (3).

7. The system according to claim 1, wherein: The system further comprises: an n-butanol purified liquid delivery pump (24) and an n-butanol cooler (16); wherein one end of the n-butanol purified liquid delivery pump (24) is connected to the middle or upper part of the distillation tower (3), and the other end of the n-butanol purified liquid delivery pump (24) is connected to the n-butanol cooler (16).

8. The system according to claim 1, wherein: The system further comprises: a steam jet vacuum pump (20), a jet pump condenser (10) and a condensate collection tank (5); wherein the permeate collection tank (4), the steam jet vacuum pump (20), the jet pump condenser (10) and the condensate collection tank (5) are connected in sequence.

9. The system according to claim 1, wherein: The system further comprises: a bottom liquid delivery pump (22) and a bottom liquid cooler (17); wherein the liquid inlet of the bottom liquid delivery pump (22) is connected to the bottom of the distillation tower (3), and the bottom liquid cooler (17) is connected to the liquid outlet of the bottom liquid delivery pump (22).

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