CN115724715A

CN115724715A - Sec-butyl alcohol refining method and device

Info

Publication number: CN115724715A
Application number: CN202211566362.8A
Authority: CN
Inventors: 刘良会; 秦艳龙; 刘郁东
Original assignee: Hunan Zhongchuang Chemical Co Ltd
Current assignee: Hunan Zhongchuang Chemical Co Ltd
Priority date: 2022-12-07
Filing date: 2022-12-07
Publication date: 2023-03-03
Anticipated expiration: 2042-12-07
Also published as: CN115724715B

Abstract

The invention relates to a refining method and a refining device of sec-butyl alcohol. The method comprises the steps of feeding sec-butyl acetate and water into a fixed bed reactor respectively for hydrolysis; sending the mixed solution after reaction into a reaction rectifying tower for further catalytic hydrolysis and rectification separation, sending a material which is rich in sec-butyl alcohol and is collected from the top of the reaction rectifying tower or the side line of the upper part of the reaction rectifying tower into a dehydrating tower for dehydration, sending a water phase into an alcohol refining tower for separation, pumping a mixture of sec-butyl alcohol and sec-butyl acetate out of the bottom of the dehydrating tower, sending the mixture of sec-butyl acetate and sec-butyl alcohol obtained from the top of the alcohol separating tower into the alcohol refining tower, and carrying out azeotropic rectification with the water phase material at the top of the dehydrating tower; sending a mixture of acetic acid and water obtained at the bottom of the reactive distillation tower into an azeotropic distillation tower, adding an azeotropic agent of sec-butyl acetate, carrying out azeotropic separation, carrying out phase separation on water distilled from the tower top and the sec-butyl acetate, carrying out total reflux on the sec-butyl acetate, extracting a water phase, and obtaining the acetic acid at the bottom of the tower.

Description

Sec-butyl alcohol refining method and device

Technical Field

The invention relates to a refining method and a refining device of sec-butyl alcohol.

Background

Sec-butyl alcohol (SBA), also known as sec-butyl alcohol, methyl ethyl methanol, sec-butyl alcohol, 2-butyl alcohol, is a colorless, transparent, flammable liquid with a wine-like odor. SBA is used industrially as a solvent, as a co-solvent with methanol, as a component for increasing the octane number of gasoline, and also for producing plasticizers, beneficiation agents, herbicides, sec-butyl esters and the like, but the most important application is the production of methyl ethyl ketone, accounting for about 90% of the total consumption. Currently, the industrially mature methods include an indirect n-butene hydration method and a direct n-butene hydration method. The traditional process for preparing sec-butyl alcohol is an indirect sulfuric acid hydration method, and the process comprises 4 working procedures of esterification, hydrolysis, rectification and dilute acid concentration. The process has low requirement on the purity of the raw material n-butene, the C4 fraction of steam cracking and the C4 fraction of a refinery can be used as raw materials, the reaction condition is mild, and the process is simple and mature. The method has the disadvantages of large consumption of sulfuric acid and caustic soda, serious pollution, low reaction selectivity, high unit consumption of n-butene, high production cost, serious equipment corrosion, need of using acid-resistant materials and the like. The direct hydration method is to prepare SBA by directly hydrating n-butene under supercritical conditions by using acidic cation exchange resin or heteropoly acid as a catalyst. The technological process has no consumption of sulfuric acid, no acid neutralizing step, no corrosion to apparatus, no waste water generation and SBA selectivity up to 99%. The method has the defects that the once-through conversion rate of the n-butene is low, only about 6 percent, the requirements on raw materials are strict, the C4 raw material used in the direct hydration process is likely to be directly hydrated into SBA under high conversion rate if the n-butene content is more than 90 percent, and the engineering cost is increased because the conversion rate is low and the circulation rate is high if the mixed C4 raw material with lower n-butene content is directly reacted, so the aim of reducing the production cost to the maximum extent is achieved by firstly carrying out extractive distillation or separation by using a molecular sieve and pre-purification.

Chinese patent CN107903150A discloses a method for producing sec-butyl alcohol by continuous hydrolysis, which takes sec-butyl acetate as a main raw material, is catalyzed and hydrolyzed by a catalyst in a reaction section of a reaction rectifying tower, and then is subjected to oil-water separation and three-step pressure-variable rectification of decompression, pressurization and decompression to obtain high-purity sec-butyl alcohol. The method adopts a coupling process of reactive distillation and variable pressure distillation to carry out the hydrolysis of the sec-butyl acetate, the hydrolysis conversion rate is high, the hydrolysis conversion rate of the sec-butyl acetate can be improved to more than 60 percent from the current 30 percent, the purity of the sec-butyl alcohol is high and can reach more than 99.97 percent, and the reaction operation condition is mild. The invention adopts a coupling process of reactive distillation and pressure swing distillation to realize continuous production of sec-butyl ester hydrolysis, but the composition change of the azeotrope of sec-butyl acetate and sec-butyl alcohol is less along with the change of pressure, so the requirements on equipment investment are high and the energy consumption is high.

Chinese patent CN108017507A discloses a method for producing high-purity sec-butyl alcohol by using water and sec-butyl acetate as raw materials through a fixed bed-reaction rectification combination method, wherein the raw materials are subjected to primary catalytic hydrolysis in a fixed bed reactor, and then sent into a reaction rectification tower for further catalytic hydrolysis to generate a crude sec-butyl alcohol product, and then subjected to oil-water separation and three-step pressure-swing rectification of decompression, pressurization and depressurization to obtain the high-purity sec-butyl alcohol. The method improves the hydrolysis conversion rate of the sec-butyl acetate by coupling the fixed bed and the reactive distillation from about 30 percent of the traditional process to more than 82 percent, but also has the problems of high equipment investment requirement and high energy consumption.

Chinese patent CN109384649A provides a method for producing sec-butyl alcohol by catalytic hydrolysis of sec-butyl acetate, which comprises the following steps: taking sec-butyl acetate as a raw material, carrying out fixed bed continuous catalytic hydrolysis, filling the catalyst into a continuous tube of a serial tubular fixed bed by adopting a commercial styrene cation exchange resin catalyst, wherein the serial tubular fixed bed comprises a plurality of identical tubular reactors, feeding the raw material sec-butyl acetate and water into the tubular reactors, carrying out continuous catalytic hydrolysis reaction under the action of the catalyst to generate a crude sec-butyl alcohol product, and refining to obtain the high-purity sec-butyl alcohol. The method only adopts a fixed bed reactor, and greatly excessive water is needed to achieve high conversion rate, so that the subsequent separation energy consumption is high, and the industrial production is difficult to realize.

Chinese patent CN109678670A discloses a method for preparing sec-butyl alcohol, which adopts a fixed bed tubular reactor, wherein the middle part is a catalyst bed layer, the upper part is provided with a partition board along the axial direction, the lower end of the partition board extends into the catalyst bed layer and does not completely penetrate through the catalyst bed layer, the reactor is divided into three parts, the two sides of the partition board are an upper feeding section and a discharging section, and a lower feeding section is arranged below a catalyst filling layer; sec-butyl acetate and water are used as a feed I and enter from a raw material inlet of an upper feeding section, water and nitrogen are used as a feed II and enter from a raw material inlet of a lower feeding section, the feed I is subjected to hydrolysis reaction in a catalyst bed layer, the reacted material is mixed with the feed II from bottom to top for further reaction, and a product is discharged from a discharge hole of a discharging section. The reaction mode of the method enables the materials to react more fully, improves the conversion rate of the hydrolysis reaction, enables the feeding at the upper end to pass through the catalyst bed layer repeatedly, enables the reaction to be more fully, and improves the conversion rate of the sec-butyl acetate. The method is only limited in the hydrolysis reaction part of the sec-butyl acetate, and a separation scheme is not considered.

The invention Chinese patent CN102659514A discloses a method for producing sec-butyl alcohol by catalytic hydrolysis of sec-butyl acetate, which comprises the following steps: the method comprises the steps of carrying out fixed bed continuous catalytic hydrolysis by taking sec-butyl acetate as a raw material, filling a commercial styrene series cation exchange resin catalyst into a continuous tube of a series tubular fixed bed, enabling the series tubular fixed bed to comprise a plurality of identical tubular reactors, enabling the raw material sec-butyl acetate and water to enter the tubular reactors, carrying out continuous catalytic hydrolysis reaction under the action of the catalyst to generate a sec-butyl alcohol crude product, and refining to obtain the high-purity sec-butyl alcohol. For refining the product sec-butyl alcohol, only the obtained mixture of sec-butyl alcohol and water is separated by standing and layering. However, in the method, unreacted sec-butyl acetate, sec-butyl alcohol obtained by hydrolysis reaction and unreacted excess water form ternary azeotropic distillation to the tower top, and water has a certain dissolving amount in both sec-butyl alcohol and sec-butyl acetate, so that a good separation effect cannot be achieved by simple standing and layering; meanwhile, since sec-butyl alcohol has a certain solubility in water, the solubility in water at 30 ℃ is 18%, if separation is carried out by standing and layering, a large amount of sec-butyl alcohol is taken away by waste water, which is not economical.

The invention Chinese patent CN106631684A discloses a method for preparing sec-butyl alcohol by hydrolyzing sec-butyl acetate, which comprises the following steps: (1) Mixing sec-butyl acetate with water, and then sending the mixture into a first hydrolysis reactor for reaction; (2) The mixture after reaction is sent to the lower part of a deacidification tower for separation, and the separated acetic acid falls into the tower bottom; (3) And (2) pumping a material from a sec-butyl alcohol enrichment area of the deacidification tower, feeding the material into a sec-butyl alcohol refining tower, simultaneously adding entrainer water, evaporating an azeotrope of water, sec-butyl acetate and part of sec-butyl alcohol to the tower top, refluxing the oil phase part subjected to condensation and layering, returning part of the oil phase part and the water phase part to a reaction system for cyclic utilization, allowing most of sec-butyl alcohol to fall into the tower bottom, and extracting the product sec-butyl alcohol from the tower bottom. The method has simple flow and simple operation, but a large amount of sec-butyl alcohol in the method is returned to the reactor as a circulating material, so that the reaction conversion rate is low, and the total yield of sec-butyl alcohol is low.

In the prior art, the conversion rate of a reaction part needs to be improved, and no particularly efficient method is available for the subsequent separation of reaction products. If the sec-butyl acetate in the separation system is preferentially removed or reduced, the circulating materials brought by ternary azeotrope of sec-butyl acetate, sec-butyl alcohol and water can be avoided; if the circulating material containing a large amount of sec-butyl alcohol in the separation system is not sent back to the reactor, the reaction equilibrium conversion rate can be effectively improved.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for preparing sec-butyl alcohol by hydrolyzing sec-butyl acetate, which comprises the following steps: (1) Respectively sending sec-butyl acetate and water into a fixed bed reactor for preliminary catalytic hydrolysis in a continuous feeding mode; (2) Sending the mixed solution after reaction extracted from the fixed bed reactor into a reaction section of a reaction rectifying tower for further catalytic hydrolysis and rectification separation, separating oil from water in a mixture of sec-butyl alcohol, sec-butyl acetate, water and a small amount of C8 hydrocarbon and C4 hydrocarbon obtained at the top of the reaction rectifying tower, sending a water phase to a feed inlet of the reaction rectifying tower, wherein an oil phase is the mixture of sec-butyl alcohol, sec-butyl acetate and a small amount of water, C8 hydrocarbon and C4 hydrocarbon, refluxing the oil phase completely or partially, extracting a material to a dehydration tower under the condition of partial reflux, and obtaining a mixture of acetic acid and water at the bottom of the reaction rectifying tower; (3) Sending a material rich in sec-butyl alcohol collected from the top or the side line of the upper part of a reactive rectifying tower (namely, a strand of material is extracted from a sec-butyl alcohol enrichment area at the upper part of the reactive rectifying tower) into a dehydrating tower for dehydration separation, evaporating a mixture of water, sec-butyl alcohol, sec-butyl acetate, C8 hydrocarbon and C4 hydrocarbon to the top of the tower, refluxing through an oil-water separation oil phase, sending a water phase into an alcohol refining tower for separation, and allowing most of the mixture of sec-butyl alcohol and sec-butyl acetate to fall into the bottom of the tower; (4) Extracting a mixture of sec-butyl alcohol and sec-butyl acetate from the bottom of a dehydrating tower, sending the mixture into an alcohol ester separation tower, and carrying out rectification separation to obtain a mixture of sec-butyl acetate and sec-butyl alcohol at the top of the tower, wherein the rest sec-butyl acetate falls into the bottom of the tower; (5) Sending the mixture of sec-butyl acetate and sec-butyl alcohol obtained from the top of the alcohol ester separation tower into an alcohol refining tower, carrying out azeotropic rectification on the mixture and a water phase material at the top of a dehydrating tower, returning the mixture of water, sec-butyl alcohol and sec-butyl acetate obtained from the top of the dehydrating tower to the dehydrating tower, and obtaining a product sec-butyl alcohol from the bottom of the dehydrating tower; (6) Sending a mixture of acetic acid and water obtained at the bottom of the reactive distillation tower into an azeotropic distillation tower, adding an azeotropic agent of sec-butyl acetate, carrying out azeotropic separation, carrying out phase separation on water and sec-butyl acetate distilled from the tower top, extracting a water phase, carrying out total reflux on an ester phase, and obtaining acetic acid at the bottom of the tower.

In the application, the purity of the sec-butyl acetate is 95-99.5%, the impurities mainly comprise sec-butyl alcohol, acetic acid, water and C8 hydrocarbon, and the content is generally but not limited to 0.01-3.5% of sec-butyl alcohol, 0.003-0.01% of acetic acid, 0.01-0.03% of water and 0.1-0.8% of C8 hydrocarbon.

The conversion per pass of the reaction of the sec-butyl acetate and water in the fixed bed reactor is low, about 50 percent, which causes that the reaction product of the subsequent separation contains a large amount of water and the sec-butyl acetate, thereby causing difficult separation and high energy consumption for separation.

The product obtained by hydrolyzing the sec-butyl acetate contains sec-butyl acetate, water and sec-butyl alcohol, wherein the boiling point of the sec-butyl alcohol is 99.5 ℃, the boiling point of the sec-butyl acetate is 111.1 ℃, and the three substances form various azeotropes in a tower, and the specific conditions are shown in the following table:

TABLE 1 azeotropy of sec-butyl acetate, water and sec-butyl alcohol

The three substances form four azeotropes, wherein the boiling points of the three azeotropes are relatively close. The mutual solubility of the three substances is poor, the sec-butyl acetate is slightly soluble in water, and the sec-butyl alcohol is not mutually soluble in water, so that the three substances can be layered in the separation process, the effect of mutual mass and heat transfer in a tower is poor, and the separation effect is poor. In the separation process, as the boiling points of three azeotropes formed by sec-butyl alcohol and water, sec-butyl acetate and water are relatively close, and the sec-butyl alcohol has hydrophilicity, most of the azeotropes are formed by the sec-butyl alcohol and water in the azeotropy process, a large amount of sec-butyl alcohol is evaporated to the tower top, and the yield of the sec-butyl alcohol product at the tower bottom is relatively low. In order to improve the yield of sec-butyl alcohol refining separation, the reaction materials are dehydrated and sec-butyl acetate is removed in the early stage of refining, the ester water content in a sec-butyl alcohol refining tower is greatly reduced, and the yield reduction caused by the fact that excessive sec-butyl alcohol is brought to the tower top by an azeotrope is avoided. Meanwhile, the circulating material containing a large amount of sec-butyl alcohol in the invention directly returns to the dehydration tower without returning to the reactor, thereby avoiding the problem of reduction of reaction conversion rate due to the existence of sec-butyl alcohol and improving the separation efficiency.

Preferably, an azeotropic agent of sec-butyl acetate is added into the azeotropic distillation tower, water and ester are mixed to achieve the azeotropic purpose, and the separation of the acetic acid is facilitated because the azeotropic temperature of the water and the ester is greatly different from the boiling point of the acetic acid. Meanwhile, as the added entrainer is the substance of sec-butyl acetate which is the substance of the whole reaction system, no new entrainer is needed to be introduced, thereby avoiding the introduction of impurities.

Preferably, the reaction pressure of the fixed bed reaction is 0.6 to 1.5MPa, preferably 0.7 to 1.5MPa, more preferably 0.8 to 1.5MPa, more preferably 0.9 to 1.4MPa, more preferably 0.9 to 1.2MPa, more preferably 0.8 to 1.2MPa, more preferably 1.0 to 1.1MPa, and further preferably 1.0MPa; the reaction temperature is 60 to 150 ℃, preferably 65 to 145 ℃, more preferably 70 to 140 ℃, more preferably 75 to 135 ℃, more preferably 80 to 130 ℃, more preferably 85 to 125 ℃, more preferably 90 to 120 ℃, more preferably 90 to 115 ℃, more preferably 90 to 110 ℃, more preferably 95 to 110 ℃, and further preferably 100 to 110 ℃; the water-ester ratio (mass ratio) is 1.05-8:1, preferably 1.1-9:1, more preferably 1.1-8:1, more preferably 1.1 to 7:1, more preferably 1.1 to 6:1, more preferably 1.1 to 5:1, more preferably 1.1 to 4:1, more preferably 1.1 to 3:1, more preferably 1.2 to 3:1, more preferably 1.3 to 3:1, more preferably 1.4 to 3:1, more preferably 1.5 to 3:1, more preferably 1.5 to 2:1.

preferably, the number of theoretical plates of the reactive distillation column is 50-70, the upper side outlet of the reactive distillation column is positioned at the 6 th to 12 th theoretical plates of the reactive distillation column, the overhead pressure of the reactive distillation column is normal pressure, the temperature of the column bottom is 110-120 ℃, preferably 111-120 ℃, more preferably 111-119 ℃, more preferably 112-118 ℃, more preferably 113-119 ℃, more preferably 113-118 ℃, more preferably 114-119 ℃, more preferably 114-118 ℃, more preferably 114-117 ℃, more preferably 115-117 ℃, further preferably 115-116 ℃, the overhead temperature is 88-92 ℃, preferably 89-92 ℃, more preferably 89-91 ℃, more preferably 90-92 ℃, further preferably 90-91 ℃, and the reflux ratio is 2-5:1, preferably 2-4:1, more preferably 3-5:1, more preferably 2-3:1, and further preferably 3-4:1.

Preferably, the mass ratio of the amount of sec-butyl alcohol rich material withdrawn from the top or upper side of the reactive distillation column (i.e. one withdrawn from the sec-butyl alcohol rich zone in the upper part of the reactive distillation column) to the sec-butyl acetate feed to the fixed bed reactor is 0.3 to 1.5, preferably 0.3 to 1.0, preferably 0.4 to 0.9, preferably 0.5 to 0.8, preferably 0.6 to 0.7.

Preferably, the pressure of the top of the dehydration tower is normal pressure, the temperature of the top of the dehydration tower is 85-92 ℃, preferably 86-91 ℃, more preferably 87-90 ℃, further preferably 88-89 ℃, the temperature of the bottom of the dehydration tower is 105-120 ℃, preferably 106-119 ℃, more preferably 107-119 ℃, more preferably 108-118 ℃, more preferably 109-117 ℃, more preferably 110-116 ℃, more preferably 111-115 ℃, more preferably 112-114 ℃, further preferably 112-113 ℃, the theoretical plates of the dehydration tower are 10-60, preferably 15-55, more preferably 20-50, more preferably 25-45, more preferably 30-40, further preferably 30-35, the oil phase at the top of the dehydration tower is totally refluxed, the water phase is discharged, and the mixture of C8 and C4 hydrocarbons is intermittently discharged at the top of the dehydration tower.

Preferably, the pressure at the top of the alcohol ester separation tower is normal pressure, the temperature at the bottom of the tower is 120-130 ℃, preferably 121-129 ℃, more preferably 122-128 ℃, more preferably 123-127 ℃, more preferably 124-126 ℃, and further preferably 125-126 ℃, the temperature at the top of the tower is 95-100 ℃, preferably 96-99 ℃, more preferably 97-99 ℃, and further preferably 97-98 ℃, and the reflux ratio is 2-5, preferably 2-4:1, more preferably 2 to 3: the theoretical plate number is 20 to 70, preferably 25 to 65, more preferably 30 to 60, more preferably 35 to 55, more preferably 40 to 50, and further preferably 40 to 55. The sec-butyl acetate obtained from the bottom of the alcohol ester separation tower returns to the fixed bed reactor for recycling, or one part returns to the fixed bed reactor, and the other part is sent to the azeotropic distillation tower to be used as the entrainer, and the proportion of the two parts can be any, for example, the mass or volume ratio of the part returned to the fixed bed reactor to the part sent to the azeotropic distillation tower can be 1.

Preferably, the pressure at the top of the alcohol refining tower is normal pressure, and the temperature at the top of the alcohol refining tower is 88-92 ℃, preferably 89-91 ℃, and further preferably 90-91 ℃; the temperature of the bottom of the tower is 99-102 ℃, preferably 99-101 ℃, and more preferably 100-101 ℃; the reflux ratio is 2-3:1, the theoretical plate number is 20-60 blocks, preferably 25-55 blocks, more preferably 30-50 blocks, more preferably 35-45 blocks, and further preferably 35-40 blocks, and the mixture at the top of the alcohol refining tower is returned to the feed of the dehydrating tower for recycling.

Preferably, the overhead pressure of the azeotropic distillation column is normal pressure, and the overhead temperature is 75 to 100 ℃, preferably 76 to 99 ℃, more preferably 77 to 98 ℃, more preferably 78 to 97 ℃, more preferably 79 to 96 ℃, more preferably 80 to 95 ℃, more preferably 81 to 94 ℃, more preferably 82 to 93 ℃, more preferably 83 to 92 ℃, more preferably 84 to 91 ℃, more preferably 85 to 90 ℃, more preferably 86 to 89 ℃, and further preferably 87 to 88 ℃; the bottom temperature of the column is 110 to 130 ℃, preferably 111 to 129 ℃, more preferably 112 to 128 ℃, more preferably 113 to 127 ℃, more preferably 114 to 126 ℃, more preferably 115 to 125 ℃, more preferably 116 to 124 ℃, more preferably 117 to 123 ℃, more preferably 118 to 122 ℃, more preferably 119 to 121 ℃, and more preferably 119 to 120 ℃; the reflux ratio is 2-3:1, oil phase total reflux is obtained after oil-water separation is carried out on a mixture of water and sec-butyl acetate obtained from the tower top, a water phase returns to a catalytic rectifying tower and/or a fixed bed reactor for recycling, and the part returning to the reactive rectifying tower and the part returning to the fixed bed reactor can be in any proportion, such as 1.

Preferably, the amount of the entrainer added is 2 to 7 times, preferably 2 to 6 times, preferably 3 to 5 times, more preferably 3.5 to 4.5 times the amount of the feed to the azeotropic column.

According to another aspect of the invention, the invention provides a device for preparing sec-butyl alcohol by hydrolyzing sec-butyl acetate, it is characterized in that the device comprises a fixed bed reactor, a reaction rectifying tower, a dehydration tower, an alcohol ester separating tower, an alcohol refining tower and an azeotropic rectifying tower which are connected in sequence, wherein the reaction rectifying tower, the dehydration tower, the alcohol ester separating tower, the alcohol refining tower and the azeotropic rectifying tower respectively comprise an overhead condenser, a reflux tank and a tower bottom reboiler, the fixed bed reactor is provided with a sec-butyl acetate feeding pipeline, a water inlet pipeline and a discharge pipeline of a mixed material after reaction, the reaction rectifying tower, the dehydration tower, the alcohol ester separating tower, the alcohol refining tower and the azeotropic rectifying tower (preferably in the middle part) are all provided with a feed inlet, the tower top reflux tank is all provided with a tower top reflux pipeline and a material discharge pipeline, the tower bottom of each tower is all provided with a material discharge pipeline, wherein a water phase discharge pipeline of a reflux tank at the top of the reaction rectifying tower is connected with a feed pipeline of the reaction rectifying tower (preferably the middle part), a discharge pipeline at the bottom of the reaction rectifying tower is connected with a feed inlet of the azeotropic rectifying tower, a side line material extraction pipeline is also arranged at the middle upper part (the top or the upper part of the tower, such as more than 1/3 of the height of the tower) of the reaction rectifying tower, the device is connected with a feed inlet of a dehydrating tower, a water phase discharge pipeline of a reflux tank at the top of the dehydrating tower is connected with a feed pipeline of an alcohol refining tower, a discharge pipeline at the bottom of the dehydrating tower is connected with a (preferred middle) feed inlet of an alcohol ester separation tower, a material pipeline of the reflux tank at the top of the alcohol ester separation tower is connected with a (preferred middle) feed inlet of the alcohol refining tower, and a material outlet pipeline of the reflux tank at the top of the alcohol refining tower is connected with a feed pipeline (preferred middle) feed pipeline or a reflux tank of the dehydrating tower.

Preferably, the outlet pipeline of the bottom of the alcohol ester separation tower is connected with the ester feeding hole of the fixed bed reactor and/or the feeding hole of the azeotropic distillation tower.

Preferably, the overhead aqueous phase discharge line of the azeotropic distillation tower is connected with the water feed inlet of the fixed bed reactor and/or the water feed inlet of the reaction distillation tower.

Preferably, a discharge pipeline of the top reflux tank of the reactive distillation column is connected with a feeding pipeline in the middle of the column, and a discharge pipeline at the bottom of the column is connected with a feeding hole of the azeotropic distillation column.

Preferably, the water phase discharge pipeline of the top reflux tank of the dehydrating tower is connected with the feeding pipeline of the alcohol refining tower, and the bottom discharge pipeline of the dehydrating tower is connected with the middle feeding hole of the alcohol ester separation tower.

Preferably, the material pipeline of the reflux tank at the top of the alcohol ester separation tower is connected with the feed inlet at the middle part of the alcohol refining tower.

Preferably, the material outlet pipeline of the reflux tank at the top of the alcohol refining tower is connected with the feeding pipeline at the middle part of the dehydrating tower.

In the invention, the conversion rate of the reaction is improved by coupling the fixed bed reactor with the catalytic rectification, and the hydrolysis single-pass conversion rate of the sec-butyl acetate is more than 90%. The separation part removes the excessive moisture in the reaction product through the dehydrating tower, the alcohol ester separation tower removes the unreacted sec-butyl acetate, the content of impurities entering the sec-butyl alcohol refining tower is greatly reduced, the content of sec-butyl alcohol entering the alcohol refining tower reaches more than 85%, the load of the sec-butyl alcohol refining tower is reduced, the one-way yield of sec-butyl alcohol is improved to more than 80%, the amount of sec-butyl alcohol circulating to the reaction part is further reduced, the adverse effect of sec-butyl alcohol on the equilibrium reaction is reduced, and the reaction conversion rate is further improved. The content of sec-butyl acetate obtained after separation by the alcohol ester separation tower is more than 98 percent, the purity requirement of the fixed bed reactor on sec-butyl acetate is met, the sec-butyl acetate can be directly recycled to the fixed bed reactor for recycling, the circulation of product alcohol in a system is reduced, and the energy consumption for separation is reduced. The alcohol refining tower has high alcohol content up to 85% and low power consumption. The circulating alcohol entering the fixed bed reactor in the system is greatly reduced, and the energy consumption for sec-butyl alcohol production is greatly reduced.

The purity of the sec-butyl alcohol obtained after separation is up to more than 99.5 percent, and the surplus moisture is separated through the dehydrating tower, so that the circulation quantity of the subsequent separation process is further reduced, and the energy consumption of the device is reduced. The sec-butyl alcohol obtained after separation completely meets the requirements of the raw materials of a downstream methyl ethyl ketone device, both sec-butyl acetate and water can be recycled, the continuous production of the sec-butyl alcohol is realized, the production scale can be obviously improved, the product quality is stable, and the obtained acetic acid byproduct can be used as the raw material for producing the sec-butyl acetate.

Drawings

FIG. 1 is a flow chart of a method for producing sec-butyl alcohol by using a mixture obtained by hydrolysis reaction of sec-butyl acetate as a raw material and performing separation steps such as dehydration, deesterification and refining.

Wherein, the method comprises the following steps of 1-sec-butyl acetate feeding pipeline, 2-water feeding pipeline, 3-fixed bed reactor, 4-discharging pipeline of mixed materials after reaction (reaction rectifying tower feeding pipeline), 5-reaction rectifying tower, 6-reaction rectifying tower top condenser (heat exchanger), 7-reaction rectifying tower top reflux tank, 8-reaction rectifying tower top reflux tank water phase discharging pipeline, 9-reflux pipeline of reaction rectifying tower top reflux tank, 10-side line material extracting pipeline (dehydrating tower feeding pipeline), 11-reaction rectifying tower kettle reboiler (heat exchanger), 12-dehydrating tower, 13-dehydrating tower top condenser (heat exchanger), 14-dehydrating tower top reflux tank, 15-reflux pipeline of dehydrating tower top reflux tank, 16-a water phase material discharge pipeline of a tower top reflux tank of the dehydration tower, 17-a reboiler (heat exchanger) at the tower bottom of the dehydration tower, a feed pipeline of an 18-alcohol ester separation tower, a 19-alcohol ester separation tower, a condenser (heat exchanger) at the tower top of the 20-alcohol ester separation tower, a reflux pipeline of a tower top reflux tank of the 21-alcohol ester separation tower, a material discharge pipeline of a tower top reflux tank of the 23-alcohol ester separation tower, a tower bottom discharge pipeline of a 24-alcohol ester separation tower, a tower bottom discharge pipeline of a 25-alcohol ester separation tower, a 26-alcohol refining tower, a condenser (heat exchanger) at the tower top of the 27-alcohol refining tower, a tower top reflux tank of the 28-alcohol refining tower and a reflux pipeline of a tower top reflux tank of the 29-alcohol refining tower, the method comprises the following steps of (1) a material discharge pipeline of a reflux tank at the top of a 30-alcohol refining tower, a reboiler (heat exchanger) of a 31-alcohol refining tower, a sec-butyl alcohol discharge pipeline of a product at the bottom of a 32-alcohol refining tower, a discharge pipeline at the bottom of a 33-reaction rectifying tower (feeding pipeline of an azeotropic rectifying tower), a 34-azeotropic rectifying tower, a condenser (heat exchanger) at the top of a 35-azeotropic rectifying tower, a reflux tank at the top of a 36-azeotropic rectifying tower, a reflux pipeline at the top of a 37-azeotropic rectifying tower, a discharge pipeline at the top of a 38-azeotropic rectifying tower, a reboiler (heat exchanger) at the bottom of a 39-azeotropic rectifying tower and a discharge pipeline at the bottom of a 40-azeotropic rectifying tower.

Detailed Description

The invention is further illustrated by the following examples. However, the present invention is not limited to the following examples, and various changes may be made to the present invention within a range not departing from the gist of the present invention, and these changes are still included in the scope of the present invention.

As shown in fig. 1, a device for preparing sec-butyl alcohol by hydrolyzing sec-butyl acetate is characterized in that the device comprises a fixed bed reactor 3, a reaction rectifying tower 5, a dehydrating tower 12, an alcohol ester separating tower 19, an alcohol refining tower 26 and an azeotropic rectifying tower 34 which are connected in sequence, the reaction rectifying tower, the dehydrating tower, the alcohol ester separating tower, the alcohol refining tower and the azeotropic rectifying tower respectively comprise a tower top condenser (6, 13, 20, 27, 35) and a reflux tank and a tower bottom reboiler (11, 17, 24, 31, 39), the fixed bed reactor is provided with a sec-butyl acetate feeding pipeline 1, a water inlet pipeline 2 and a discharge pipeline 4 of reacted mixed materials, the reaction rectifying tower, the dehydrating tower, the alcohol ester separating tower, the alcohol refining tower and the azeotropic rectifying tower are respectively provided with a feeding port at the middle part, the tower top reflux tank is provided with a tower top reflux pipeline (9, 15, 22, 29, 37) and a material discharge pipeline (8, 16, 23, 30, 38), each tower is provided with a material discharge pipeline (33, 18, 25, 32, 40), the reaction rectifying tower top reflux tank is provided with a side reflux pipeline (7), the tower bottom reflux pipeline is connected with a lateral line (19), the dehydration rectifying tower is connected with a water phase reflux distillation tower is connected with a reaction rectifying tower bottom reflux distillation tower, the reaction rectifying tower is provided with a reaction rectifying tower is connected with a material extraction pipeline (14), the dehydration rectifying tower is connected with a lateral line, the reaction rectifying tower top reflux distillation tower is connected with a reaction rectifying tower top reflux pipeline (16), the material outlet pipeline of the reflux drum 28 at the top of the alcohol refining tower is connected with the feeding pipeline (or reflux drum) at the middle part of the dehydrating tower 12.

The fixed bed reactor is provided with a sec-butyl acetate feeding pipeline, a water inlet pipeline and a discharge pipeline of a mixed material after reaction.

And a discharge pipeline of the reflux tank at the top of the reactive distillation tower is connected with a feed pipeline at the middle part of the reactive distillation tower, and a discharge pipeline at the bottom of the reactive distillation tower is connected with a feed inlet of the azeotropic distillation tower.

The discharge pipeline of the top reflux tank of the dehydrating tower 12 is connected with the feed pipeline of the alcohol refining tower 26, and the discharge pipeline of the bottom of the dehydrating tower is connected with the middle feed pipeline of the alcohol ester separation tower 19.

And a material discharge pipeline of the reflux tank at the top of the alcohol ester separation tower 19 is connected with a middle feed inlet of the alcohol refining tower 26.

The material outlet pipeline of the reflux tank at the top of the alcohol refining tower 26 is connected with the feeding pipeline at the middle part of the dehydrating tower 12.

The bottom discharge line of the alcohol ester separation tower 19 can be connected with the ester feeding hole of the fixed bed reactor and/or the feeding hole of the azeotropic distillation tower.

The water phase pipeline of the reflux tank at the top of the azeotropic distillation tower can be connected with the water feed inlet of the fixed bed reactor and/or the feed inlet of the reactive distillation tower.

Example 1

Respectively feeding 500g of sec-butyl acetate and 155g of water into a fixed bed reactor for preliminary catalytic hydrolysis by adopting a continuous feeding mode, wherein the composition of the raw material sec-butyl acetate comprises 99.5% of sec-butyl acetate, 0.01% of sec-butyl alcohol, 0.006% of acetic acid, 0.01% of water and 0.47% of C8 hydrocarbon impurities, the reaction pressure of the fixed bed reaction is 0.8MPa, the reaction temperature is 110 ℃, and the water-ester ratio is 2.5. Sending the reacted mixed solution extracted by the fixed bed reactor into a reaction section of a reaction rectifying tower for further catalytic hydrolysis and rectification separation, separating oil and water of a mixture of sec-butyl alcohol, sec-butyl acetate, water and a small amount of C8 hydrocarbon and C4 hydrocarbon from the top of the reaction rectifying tower, refluxing a water phase to a feed inlet of the reaction rectifying tower, obtaining a mixture of sec-butyl alcohol, sec-butyl acetate, a small amount of water, C8 hydrocarbon and C4 hydrocarbon from an oil phase, and obtaining a mixture of acetic acid and water from the bottom of the reaction rectifying tower, wherein the theoretical plate number of the reaction rectifying tower is 65, a side draw outlet (sec-butyl alcohol enrichment area) is positioned at the 8 th theoretical plate of the reaction rectifying tower, the pressure of the top of the reaction rectifying tower is normal pressure, the temperature of a tower kettle is 110 ℃, the temperature of the top of the tower is 88 ℃, and the reflux ratio is 2.5:1. 340-380g of material is pumped from a sec-butyl alcohol enrichment area at the upper part of a reactive distillation tower and sent into a dehydration tower for dehydration separation, wherein the top pressure of the dehydration tower is normal pressure, the number of theoretical plates is 32, the temperature of the top of the tower is 85 ℃, the temperature of a tower kettle is 105 ℃, an oil phase at the top of the tower is totally refluxed, a water phase is discharged, a mixture of C8 and C4 hydrocarbons is intermittently discharged at the top of the tower, the mixture of water, sec-butyl alcohol, sec-butyl acetate, C8 hydrocarbons and C4 hydrocarbons is steamed to the top of the tower, the oil phase is refluxed through oil-water separation, the water phase is sent into an alcohol refining tower for separation, and most of sec-butyl acetate falls into the bottom of the dehydration tower. Feeding the tower bottom material of the dehydrating tower into an alcohol ester separation tower for separation, feeding the sec-butyl acetate obtained at the tower bottom of the alcohol ester separation tower back to a fixed bed reactor for recycling, feeding a mixture of the sec-butyl acetate and the sec-butyl alcohol obtained at the tower top of the alcohol ester separation tower into an alcohol refining tower, wherein the tower top pressure of the alcohol ester separation tower is normal pressure, the theoretical plate number is 45, the tower bottom temperature is 120 ℃, the tower top temperature is 95 ℃, and the reflux ratio is 2:1. the method comprises the following steps of mixing the discharge of a reflux tank at the top of an alcohol ester separation tower with the water of a reflux tank of a dehydration tower, feeding the mixture into an alcohol refining tower, performing azeotropic distillation, refluxing a part of the mixture of water, sec-butyl alcohol and sec-butyl acetate obtained at the top of the tower, recycling a part of the mixture into a feed pipeline of the dehydration tower, and obtaining a product of sec-butyl alcohol at the bottom of the tower, wherein the pressure at the top of the alcohol refining tower is normal pressure, the number of theoretical plates is 45, the temperature of a tower kettle is 99 ℃, the temperature of the top of the tower is 88 ℃, and the reflux ratio is 2.2:1.

sending a mixture of acetic acid and water obtained at the bottom of the reactive distillation tower into an azeotropic distillation tower, wherein the pressure at the top of the azeotropic distillation tower is normal pressure, the temperature at the top of the azeotropic distillation tower is 75 ℃, the temperature at the bottom of the azeotropic distillation tower is 110 ℃, and the reflux ratio is 2.5:1, adding an entrainer sec-butyl acetate in an amount which is about 3 times of the feeding amount of an azeotropic distillation tower, carrying out azeotropic separation to obtain a mixture of water and the sec-butyl acetate at the tower top, obtaining acetic acid at the tower bottom, carrying out oil-water separation on the mixture of the water and the sec-butyl acetate obtained at the tower top to obtain an oil phase which is subjected to total reflux, and returning the water phase to the reactive distillation tower for recycling. Through chromatographic analysis, the hydrolysis conversion rate of the sec-butyl acetate can reach 90 percent, and the purity of the sec-butyl alcohol product is 99.85 percent.

Example 2

Respectively feeding 500g of sec-butyl acetate and 155g of water into a fixed bed reactor for preliminary catalytic hydrolysis by adopting a continuous feeding mode, wherein the composition of the raw material sec-butyl acetate comprises 99.4% of sec-butyl acetate, 0.02% of sec-butyl alcohol, 0.005% of acetic acid, 0.01% of water and 0.56% of C8 hydrocarbon impurities, the reaction pressure of the fixed bed reaction is 1.2MPa, the reaction temperature is 112 ℃, and the molar ratio of water to ester is 3:1. Sending the reacted mixed solution extracted from the fixed bed reactor into a reaction section of a reaction rectifying tower for further catalytic hydrolysis and rectification separation, separating oil from water in a mixture of sec-butyl alcohol, sec-butyl acetate, water and a small amount of C8 hydrocarbon and C4 hydrocarbon obtained at the top of the reaction rectifying tower, refluxing a water phase to a feed inlet of the reaction rectifying tower, obtaining a mixture of sec-butyl alcohol, sec-butyl acetate, a small amount of water, C8 hydrocarbon and C4 hydrocarbon in an oil phase, and obtaining a mixture of acetic acid and water at the bottom of the tower, wherein the number of theoretical plates of the reaction rectifying tower is 70, a side draw outlet (sec-butyl alcohol enrichment area) is positioned at the 12 th theoretical plate of the reaction rectifying tower, the pressure at the top of the tower is normal pressure, the temperature at the bottom of the tower is 120 ℃, the temperature at the top of the tower is 92 ℃, and the reflux ratio is 4:1. pumping 420-460g of a material from a sec-butyl alcohol enrichment area at the upper part of a reactive distillation tower, feeding the material into a dehydration tower for dehydration and separation, wherein the top pressure of the dehydration tower is normal pressure, the number of theoretical plates is 35, the temperature of the top of the tower is 92 ℃, the temperature of a tower kettle is 120 ℃, the oil phase at the top of the tower is totally refluxed, a water phase is discharged, a mixture of C8 and C4 hydrocarbons is intermittently discharged from the top of the tower, the mixture of water, sec-butyl alcohol, sec-butyl acetate, C8 hydrocarbons and C4 hydrocarbons is steamed to the top of the tower, the oil phase is refluxed after oil-water separation, the water phase is fed into an alcohol refining tower for separation, and most of sec-butyl acetate falls into the bottom of the dehydration tower. Feeding the tower bottom material of a dehydrating tower into an alcohol ester separation tower for separation, feeding part of sec-butyl acetate obtained from the tower bottom of the alcohol ester separation tower back to a fixed bed reactor, feeding the other part of sec-butyl acetate into an azeotropic distillation tower for recycling, wherein the volume ratio of the two parts is 1.2, feeding a mixture of sec-butyl acetate and sec-butyl alcohol obtained from the tower top of the alcohol ester separation tower into an alcohol refining tower, wherein the tower top pressure of the alcohol ester separation tower is normal pressure, the theoretical plate number is 50, the tower bottom temperature is 130 ℃, the tower top temperature is 100 ℃, and the reflux ratio is 5:1. the method comprises the following steps of mixing the discharge of a reflux tank at the top of an alcohol ester separation tower with the water of a reflux tank of a dehydrating tower, feeding the mixture into an alcohol refining tower, performing azeotropic distillation, wherein part of the mixture of water, sec-butyl alcohol and sec-butyl acetate obtained at the top of the tower partially refluxes, and the other part of the mixture enters a feed pipeline of the dehydrating tower for recycling, and the product sec-butyl alcohol is obtained at the bottom of the tower, wherein the pressure at the top of the alcohol refining tower is normal pressure, the number of theoretical plate is 40, the temperature of a tower kettle is 100 ℃, the temperature of the top of the tower is 90 ℃, and the reflux ratio is 2.5:1.

sending a mixture of acetic acid and water obtained at the bottom of the reactive distillation tower into an azeotropic distillation tower, wherein the pressure at the top of the azeotropic distillation tower is normal pressure, the temperature at the top of the azeotropic distillation tower is 80 ℃, the temperature at the bottom of the tower is 115 ℃, and the reflux ratio is 3:1, adding an entrainer sec-butyl acetate in an amount which is 4 times of the feeding amount of an azeotropic distillation tower, performing azeotropic separation to obtain a mixture of water and sec-butyl acetate at the tower top, obtaining acetic acid at the tower bottom, performing oil-water separation on the mixture of water and sec-butyl acetate obtained at the tower top to obtain an oil phase, performing total reflux on the water phase, returning part of the water phase to the catalytic distillation tower, and recycling the feeding material returned to the fixed bed reactor. Through chromatographic analysis, the hydrolysis conversion rate of the sec-butyl acetate can reach 91.5 percent, and the purity of the sec-butyl alcohol product is 99.75 percent.

Example 3

Respectively feeding 500g of sec-butyl acetate and 155g of water into a fixed bed reactor for preliminary catalytic hydrolysis by adopting a continuous feeding mode, wherein the raw material sec-butyl acetate comprises 99.2% of sec-butyl acetate, 0.03% of sec-butyl alcohol, 0.005% of acetic acid, 0.02% of water and 0.74% of C8 hydrocarbon impurities, the reaction pressure of fixed bed reaction is 1.5MPa, the reaction temperature is 115 ℃, and the molar ratio of water to ester is 4:1. Sending the reacted mixed solution extracted by the fixed bed reactor into a reaction section of a reaction rectifying tower for further catalytic hydrolysis and rectification separation, separating oil from water in a mixture of sec-butyl alcohol, sec-butyl acetate, water and a small amount of C8 hydrocarbon and C4 hydrocarbon obtained at the top of the reaction rectifying tower, refluxing a water phase to a feed inlet of the reaction rectifying tower, obtaining a mixture of sec-butyl alcohol, sec-butyl acetate, a small amount of water, C8 hydrocarbon and C4 hydrocarbon in an oil phase, and obtaining a mixture of acetic acid and water at the bottom of the tower, wherein the theoretical plate number of the reaction rectifying tower is 60, a side draw outlet (sec-butyl alcohol enrichment area) is positioned at the 7 th theoretical plate of the reaction rectifying tower, the pressure at the top of the reaction rectifying tower is normal pressure, the temperature at the bottom of the tower is 115 ℃, the temperature at the top of the tower is 90 ℃, and the reflux ratio is 3.5:1. 480-520g of material is extracted from a sec-butyl alcohol enrichment area at the upper part of a reactive distillation tower and sent into a dehydration tower for dehydration and separation, wherein the top pressure of the dehydration tower is normal pressure, the number of theoretical plates is 45, the temperature of the top of the tower is 89 ℃, the temperature of a tower kettle is 113 ℃, the oil phase at the top of the tower is totally refluxed, the water phase is discharged, and the mixture of C8 and C4 hydrocarbons is intermittently discharged at the top of the tower. And (3) evaporating a mixture of water, sec-butyl alcohol, sec-butyl acetate, C8 hydrocarbon and C4 hydrocarbon to the tower top, refluxing through an oil-water separation oil phase, sending a water phase into an alcohol refining tower for separation, and allowing most of sec-butyl acetate to fall into the tower bottom. Feeding the tower bottom material of the dehydrating tower into an alcohol ester separation tower for further separation, feeding the sec-butyl acetate obtained from the tower bottom of the alcohol ester separation tower back to the fixed bed reactor for recycling, and feeding a mixture of the sec-butyl acetate and the sec-butyl alcohol obtained from the tower top into an alcohol refining tower, wherein the tower top pressure of the alcohol ester separation tower is normal pressure, the theoretical plate number is 40, the tower kettle temperature is 126 ℃, the tower top temperature is 98 ℃, and the reflux ratio is 3:1. mixing the discharge of a reflux tank at the top of the alcohol ester separation tower with the water of a reflux tank of a dehydrating tower, feeding the mixture into an alcohol refining tower, performing azeotropic distillation, wherein part of the mixture of water, sec-butyl alcohol and sec-butyl acetate obtained at the top of the tower reflows, and the other part of the mixture enters a feed pipeline of the dehydrating tower for recycling, and the product sec-butyl alcohol is obtained at the bottom of the tower, wherein the pressure at the top of the alcohol refining tower is normal pressure, the number of theoretical plate is 36, the temperature of a tower kettle is 101 ℃, the temperature of the top of the tower is 91 ℃, and the reflux ratio is 3:1.

sending a mixture of acetic acid and water obtained at the bottom of the reactive distillation tower into an azeotropic distillation tower, wherein the pressure at the top of the azeotropic distillation tower is normal pressure, the temperature at the top of the azeotropic distillation tower is 88 ℃, the temperature at the bottom of the azeotropic distillation tower is 120 ℃, and the reflux ratio is 2:1, adding an entrainer sec-butyl acetate in an amount which is 5 times of the feeding amount of an azeotropic distillation tower, carrying out azeotropic separation to obtain a mixture of water and sec-butyl acetate at the tower top, obtaining acetic acid at the tower bottom, carrying out oil-water separation on the mixture of water and sec-butyl acetate obtained at the tower top to obtain an oil phase which is subjected to total reflux, and returning the water phase to the reactive distillation tower for recycling. Through chromatographic analysis, the hydrolysis conversion rate of the sec-butyl acetate can reach 88.6 percent, and the purity of the sec-butyl alcohol product is 99.78 percent.

Example 4

The method comprises the steps of respectively feeding 500g of sec-butyl acetate and 155g of water into a fixed bed reactor for preliminary catalytic hydrolysis by adopting a continuous feeding mode, wherein the sec-butyl acetate raw material comprises 98.10%, 1.42% of sec-butyl alcohol, 0.006% of acetic acid, 0.01% of water and 0.47% of C8 hydrocarbon impurities, the reaction pressure of a fixed bed reaction is 1.2MPa, the reaction temperature is 105 ℃, and the molar ratio of water to ester is 5:1. Sending the reacted mixed solution extracted by the fixed bed reactor into a reaction section of a reaction rectifying tower for further catalytic hydrolysis and rectification separation, separating oil and water of a mixture of sec-butyl alcohol, sec-butyl acetate, water and a small amount of C8 hydrocarbon and C4 hydrocarbon from the top of the reaction rectifying tower, refluxing a water phase to a feed inlet of the reaction rectifying tower, obtaining a mixture of sec-butyl alcohol, sec-butyl acetate, a small amount of water, C8 hydrocarbon and C4 hydrocarbon from an oil phase, and obtaining a mixture of acetic acid and water from the bottom of the reaction rectifying tower, wherein the number of theoretical plate of the reaction rectifying tower is 68, a sec-butyl alcohol enrichment region is positioned at the 9 th theoretical plate of the reaction rectifying tower, the pressure at the top of the reaction rectifying tower is normal pressure, the temperature at the bottom of the tower is 112 ℃, the temperature at the top of the tower is 85 ℃, and the reflux ratio is 3.2. And (2) pumping 560-600g of material from a sec-butyl alcohol enrichment area at the upper part of the reactive distillation tower, and feeding the material into a dehydration tower for dehydration separation, wherein the tower top pressure of the dehydration tower is normal pressure, the number of theoretical plates is 50, the tower top temperature is 91 ℃, the tower bottom temperature is 108 ℃, the oil phase at the tower top is totally refluxed, the water phase is discharged, and the mixture of C8 and C4 hydrocarbons is intermittently discharged at the tower top. And (3) evaporating a mixture of water, sec-butyl alcohol, sec-butyl acetate, C8 hydrocarbon and C4 hydrocarbon to the tower top, refluxing through an oil-water separation oil phase, sending a water phase into an alcohol refining tower for separation, and allowing most of sec-butyl acetate to fall into the tower bottom. Feeding the tower bottom material of the dehydrating tower into an alcohol ester separation tower for further separation, feeding the sec-butyl acetate obtained at the tower bottom of the alcohol ester separation tower back to the fixed bed reactor for recycling, and feeding a mixture of the sec-butyl acetate and the sec-butyl alcohol obtained at the tower top into an alcohol refining tower, wherein the tower top pressure of the alcohol ester separation tower is normal pressure, the theoretical plate number is 46, the tower bottom temperature is 120 ℃, the tower top temperature is 100 ℃, and the reflux ratio is 4:1. mixing the discharge of a reflux tank at the top of the alcohol ester separation tower with the water of a reflux tank of a dehydrating tower, feeding the mixture into an alcohol refining tower, performing azeotropic distillation, wherein part of the mixture of water, sec-butyl alcohol and sec-butyl acetate obtained at the top of the tower reflows, and the other part of the mixture enters a feed pipeline of the dehydrating tower for recycling, and the product of sec-butyl alcohol is obtained at the bottom of the tower, wherein the pressure at the top of the alcohol refining tower is normal pressure, the number of theoretical plate is 46, the temperature of a tower kettle is 102 ℃, the temperature of the top of the tower is 92 ℃, and the reflux ratio is 2.8:1.

sending a mixture of acetic acid and water obtained at the bottom of the reactive distillation tower into an azeotropic distillation tower, wherein the pressure at the top of the azeotropic distillation tower is normal pressure, the temperature at the top of the azeotropic distillation tower is 85 ℃, the temperature at the bottom of the tower is 118 ℃, and the reflux ratio is 2.4:1, adding an entrainer sec-butyl acetate in an amount which is 6 times of the feeding amount of an azeotropic distillation tower, carrying out azeotropic separation to obtain a mixture of water and sec-butyl acetate at the tower top, obtaining acetic acid at the tower bottom, carrying out oil-water separation on the mixture of water and sec-butyl acetate obtained at the tower top to obtain an oil phase which is subjected to total reflux, and returning the water phase to the reactive distillation tower for recycling. Through chromatographic analysis, the hydrolysis conversion rate of the sec-butyl acetate can reach 86.7 percent, and the purity of the sec-butyl alcohol product is 99.69 percent.

Example 5

Respectively feeding 500g of sec-butyl acetate and 155g of water into a fixed bed reactor for preliminary catalytic hydrolysis by adopting a continuous feeding mode, wherein the composition of the raw material sec-butyl acetate is 96.80%, 3.02% of sec-butyl alcohol, 0.006% of acetic acid, 0.01% of water and 0.17% of C8 hydrocarbon impurities, the reaction pressure of the fixed bed reaction is 1.4MPa, the reaction temperature is 100 ℃, and the water-ester ratio is 3.5. Sending the reacted mixed solution extracted by the fixed bed reactor into a reaction section of a reaction rectifying tower for further catalytic hydrolysis and rectification separation, separating oil and water of a mixture of sec-butyl alcohol, sec-butyl acetate, water and a small amount of C8 hydrocarbon and C4 hydrocarbon from the top of the reaction rectifying tower, refluxing a water phase to a feed inlet of the reaction rectifying tower, obtaining a mixture of sec-butyl alcohol, sec-butyl acetate, a small amount of water, C8 hydrocarbon and C4 hydrocarbon from an oil phase, and obtaining a mixture of acetic acid and water from the bottom of the reaction rectifying tower, wherein the number of theoretical plate of the reaction rectifying tower is 58, a sec-butyl alcohol enrichment region is located at the 5 th theoretical plate of the reaction rectifying tower, the pressure at the top of the reaction rectifying tower is normal pressure, the temperature at the bottom of the tower is 113 ℃, the temperature at the top of the tower is 90 ℃, and the reflux ratio is 2.7. And (2) extracting 600-640g of a material from a sec-butyl alcohol enrichment area at the upper part of the reactive distillation tower, and feeding the material into a dehydration tower for dehydration separation, wherein the tower top pressure of the dehydration tower is normal pressure, the number of theoretical plates is 42, the tower top temperature is 82 ℃, the tower bottom temperature is 102 ℃, the oil phase at the tower top is totally refluxed, the water phase is discharged, and the mixture of C8 and C4 hydrocarbons is intermittently discharged at the tower top. And (3) evaporating a mixture of water, sec-butyl alcohol, sec-butyl acetate, C8 hydrocarbon and C4 hydrocarbon to the tower top, refluxing through an oil-water separation oil phase, sending a water phase into an alcohol refining tower for separation, and allowing most of sec-butyl acetate to fall into the tower bottom. Feeding the tower bottom material of the dehydrating tower into an alcohol ester separation tower for further separation, returning the sec-butyl acetate obtained at the tower bottom of the alcohol ester separation tower to a fixed bed reactor for feeding for recycling, and feeding a mixture of the sec-butyl acetate and the sec-butyl alcohol obtained at the tower top into an alcohol refining tower, wherein the pressure at the tower top of the alcohol ester separation tower is normal pressure, the number of theoretical plates is 55, the temperature at the tower bottom is 122 ℃, the temperature at the tower top is 96 ℃, and the reflux ratio is 4.5:1. mixing the discharge of a reflux tank at the top of the alcohol ester separation tower with the water of a reflux tank of a dehydrating tower, feeding the mixture into an alcohol refining tower, performing azeotropic distillation, wherein part of the mixture of water, sec-butyl alcohol and sec-butyl acetate obtained at the top of the tower reflows, and the other part of the mixture enters a feed pipeline of the dehydrating tower for recycling, and the product sec-butyl alcohol is obtained at the bottom of the tower, wherein the pressure at the top of the alcohol refining tower is normal pressure, the number of theoretical plate is 51, the temperature of a tower kettle is 101 ℃, the temperature of the top of the tower is 92 ℃, and the reflux ratio is 2.4:1.

sending a mixture of acetic acid and water obtained at the bottom of the reactive distillation tower into an azeotropic distillation tower, wherein the pressure at the top of the azeotropic distillation tower is normal pressure, the temperature at the top of the azeotropic distillation tower is 78 ℃, the temperature at the bottom of the azeotropic distillation tower is 112 ℃, and the reflux ratio is 2.6:1, adding an entrainer sec-butyl acetate in an amount which is 3.5 times of the feeding amount of an azeotropic distillation tower, carrying out azeotropic separation to obtain a mixture of water and sec-butyl acetate at the tower top, obtaining acetic acid at the tower bottom, carrying out oil-water separation on the mixture of water and sec-butyl acetate obtained at the tower top to obtain an oil phase which is subjected to total reflux, and returning the water phase to the reactive distillation tower for recycling. Through chromatographic analysis, the hydrolysis conversion rate of the sec-butyl acetate can reach 85.2 percent, and the purity of the sec-butyl alcohol product is 99.61 percent.

The foregoing detailed description describes in detail preferred embodiments of the present invention, however, it should be understood that the foregoing description is intended for purposes of illustration only and is not intended to limit the scope of the invention in any way. Alterations and changes in certain features of this invention may be made by those skilled in the art without departing from the spirit and scope of this invention, which should be considered to be within the scope of the claims appended hereto.

Claims

1. A method for preparing sec-butyl alcohol by hydrolyzing sec-butyl acetate comprises the following steps: (1) Respectively sending sec-butyl acetate and water into a fixed bed reactor for preliminary catalytic hydrolysis in a continuous feeding mode; (2) Sending the reacted mixed solution extracted by the fixed bed reactor into a reaction section of a reaction rectifying tower for further catalytic hydrolysis and rectification separation, separating oil and water of a mixture of sec-butyl alcohol, sec-butyl acetate, water and a small amount of C8 hydrocarbon and C4 hydrocarbon obtained at the top of the reaction rectifying tower, refluxing a water phase to a feed inlet of the reaction rectifying tower, obtaining a mixture of sec-butyl alcohol, sec-butyl acetate and a small amount of water, C8 hydrocarbon and C4 hydrocarbon from an oil phase, and obtaining a mixture of acetic acid and water at the bottom of the reaction rectifying tower; (3) Sending the material rich in sec-butyl alcohol collected from the top of the reactive distillation tower or the side line of the upper part of the tower into a dehydrating tower for dehydration separation, evaporating the mixture of water, sec-butyl alcohol, sec-butyl acetate, C8 hydrocarbon and C4 hydrocarbon to the top of the tower, refluxing through an oil-water separation oil phase, sending a water phase into an alcohol refining tower for separation, and enabling most of the mixture of sec-butyl alcohol and sec-butyl acetate to fall into the bottom of the tower; (4) Extracting a mixture of sec-butyl alcohol and sec-butyl acetate from the bottom of a dehydrating tower, sending the mixture into an alcohol ester separation tower, and carrying out rectification separation to obtain a mixture of sec-butyl acetate and sec-butyl alcohol at the top of the tower, wherein the rest sec-butyl acetate falls into the bottom of the tower; (5) Sending the mixture of sec-butyl acetate and sec-butyl alcohol obtained from the top of the alcohol ester separation tower into an alcohol refining tower, carrying out azeotropic rectification on the mixture and a water phase material at the top of a dehydrating tower to obtain a mixture of water, sec-butyl alcohol and sec-butyl acetate at the top of the tower, and obtaining a product sec-butyl alcohol at the bottom of the tower; (6) Sending a mixture of acetic acid and water obtained at the bottom of the reactive distillation tower into an azeotropic distillation tower, adding an azeotropic agent of sec-butyl acetate, carrying out azeotropic separation, carrying out phase separation on water distilled from the tower top and the sec-butyl acetate, carrying out total reflux on the sec-butyl acetate, extracting a water phase, and obtaining the acetic acid at the bottom of the tower.

2. The method of claim 1, wherein: the reaction pressure of the fixed bed reaction is 0.6-1.5MPa, preferably 0.8-1.5MPa, more preferably 0.8-1.2MPa, and further preferably 1.0MPa; the reaction temperature is 60-150 ℃, preferably 70-140 ℃, more preferably 80-130 ℃, and further preferably 90-110 ℃; the water-ester ratio is 1.05-8:1, preferably 1.1-5:1, more preferably 1.2-3:1, and still more preferably 1.5-2:1.

3. The method according to any one of claims 1 or 2, characterized in that: the theoretical plate number of the reaction rectifying tower is 50-70, preferably 52-68, more preferably 55-65, and further preferably 58-62; the upper side line extraction outlet of the reaction rectifying tower is positioned at the 6 th to 12 th theoretical plates of the reaction rectifying tower, preferably at the 6 th to 11 th theoretical plates, more preferably at the 7 th to 10 th theoretical plates, and further preferably at the 8 th to 9 th theoretical plates; the pressure at the top of the reactive distillation column is normal pressure, and the temperature at the top of the reactive distillation column is 80-100 ℃, preferably 82-98 ℃, more preferably 85-95 ℃, and further preferably 88-92 ℃; the temperature of the tower bottom is 105-125 ℃, preferably 108-122 ℃, more preferably 110-120 ℃, and further preferably 112-118 ℃; the reflux ratio is 1 to 8, preferably 1 to 6, more preferably 2 to 5, and further preferably 2 to 4; and/or

The mass ratio of the quantity of the material rich in sec-butyl alcohol extracted from the top of the reactive distillation tower or the side line at the upper part of the tower to the sec-butyl acetate fed into the fixed bed reactor is 0.3-1.5.

4. A method according to claims 1-3, characterized in that: the tower top pressure of the dehydration tower is normal pressure, the tower top temperature is 80-100 ℃, preferably 82-98 ℃, more preferably 85-95 ℃, and further preferably 88-92 ℃; the temperature of the column bottom is 100-120 ℃, preferably 105-120 ℃, more preferably 105-115 ℃, and further preferably 108-112 ℃; the aqueous phase is taken off at the top of the column, the oil phase is refluxed completely, and a mixture of C8 and C4 hydrocarbons is preferably discharged intermittently at the top of the column.

5. The method according to any one of claims 1-4, characterized in that: the pressure at the top of the alcohol ester separation tower is normal pressure, the temperature at the top of the alcohol ester separation tower is 85-105 ℃, preferably 88-102 ℃, more preferably 90-100 ℃, and further preferably 95-100 ℃; the temperature of the tower kettle is 115-135 ℃, preferably 118-132 ℃, more preferably 120-130 ℃, and further preferably 122-128 ℃; the reflux ratio is 1 to 10, preferably 1.5 to 8, more preferably 2 to 6, and further preferably 2 to 5.

6. The method according to any one of claims 1-5, characterized in that: and returning sec-butyl acetate obtained at the bottom of the alcohol ester separation tower to the fixed bed reactor for feeding and recycling.

7. The method according to any one of claims 1-6, characterized in that: the pressure at the top of the alcohol refining tower is normal pressure, the temperature at the top of the alcohol refining tower is 85-95 ℃, the temperature at the top of the alcohol refining tower is preferably 86-94 ℃, the temperature at the top of the alcohol refining tower is preferably 86-92 ℃, the temperature at the bottom of the alcohol refining tower is further preferably 88-92 ℃, the temperature at the bottom of the alcohol refining tower is 90-110 ℃, the temperature at the bottom of the alcohol refining tower is preferably 92-108 ℃, the temperature at the bottom of the alcohol refining tower is preferably 95-105 ℃, and the temperature at the bottom of the alcohol refining tower is further preferably 98-102 ℃; the reflux ratio is 1 to 8, preferably 1 to 6, more preferably 2 to 5, and further preferably 2 to 3.

8. The method according to any one of claims 1-7, characterized in that: and the mixture at the top of the alcohol refining tower returns to the dehydrating tower for feeding or the reflux tank at the top of the dehydrating tower for recycling.

9. The method according to any one of claims 1-8, characterized in that: the overhead pressure of the azeotropic distillation tower is normal pressure, and the overhead temperature is 75-100 ℃, preferably 80-95 ℃, more preferably 82-92 ℃, and further preferably 85-90 ℃; the temperature of the tower bottom is 100-130 ℃, preferably 105-125 ℃, more preferably 110-120 ℃, and further preferably 112-118 ℃; the reflux ratio is 1 to 6, preferably 1.5 to 5, more preferably 1.8 to 4, further preferably 2 to 3; and/or

Refluxing an oil phase obtained by oil-water separation of a mixture of water and sec-butyl acetate obtained at the tower top, and returning a water phase to a reaction rectifying tower and/or a fixed bed reactor for recycling; and the acetic acid obtained at the tower bottom is recycled as a raw material for synthesizing sec-butyl acetate.

10. The device for preparing sec-butyl alcohol by hydrolyzing sec-butyl acetate is characterized by comprising a fixed bed reactor, a reaction rectifying tower, a dehydrating tower, an alcohol ester separating tower, an alcohol refining tower and an azeotropic rectifying tower which are sequentially connected, wherein the reaction rectifying tower, the dehydrating tower, the alcohol ester separating tower, the alcohol refining tower and the azeotropic rectifying tower respectively comprise a tower top condenser, a reflux tank and a tower bottom reboiler, the fixed bed reactor is provided with a sec-butyl acetate feeding pipeline, a water inlet pipeline and a discharge pipeline of a mixed material after reaction, the reaction rectifying tower, the dehydrating tower, the alcohol ester separating tower, the alcohol refining tower and the azeotropic rectifying tower are respectively provided with a feeding hole, the tower top reflux tank is provided with a tower top reflux pipeline and a material discharge pipeline, all be provided with material discharging pipeline at the bottom of each tower, wherein, the aqueous phase discharging pipeline of reaction rectifying tower top of the tower reflux drum links to each other with reaction rectifying tower feedstock line, reaction rectifying tower bottom of the tower discharging pipeline links to each other with the feed inlet of azeotropic distillation tower, the well upper portion of reaction rectifying tower still is provided with the side draw material pipeline, link to each other with the dehydration tower feed inlet, dehydration tower top of the tower reflux drum aqueous phase discharging pipeline links to each other with alcohol refining tower feedstock line, dehydration tower bottom of the tower discharging pipeline links to each other with the feed inlet of alcohol ester knockout tower, alcohol ester knockout tower top of the tower reflux drum discharging pipeline links to each other with alcohol refining tower feed inlet, alcohol refining tower top of the tower reflux drum material outlet pipeline links to each other with dehydration tower inlet pipe line or reflux drum.