An apparatus and method for continuous rectification separation of ethanol, n-butanol and higher alcohols

Abstract

The application discloses a production device and method for continuously rectifying and separating ethanol, n-butanol and higher alcohols, which comprises 12 rectifying towers, one phase separator and one heat exchanger, and is mainly divided into three steps of light component separation, alcohol-water separation and higher alcohol separation; the mixed solution after the reaction of catalytic conversion of ethanol into higher alcohols is used as raw material, first, ethyl acetate, aldehyde and part of ethanol are removed through an ethyl acetate tower, the liquid at the bottom of the ethyl acetate tower is separated into ethanol, water and n-butanol and other light components through a light component separation tower, then, ethanol is separated through extractive rectification, and the circulation reflux design is adopted in the separation of n-butanol and water, so that the alcohol-water separation is realized efficiently; at the same time, the light component separation tower is connected with a higher alcohol separation system, so that 2-ethylbutanol, n-hexanol, 2-ethylhexanol, n-octanol, 2-ethyloctanol and n-decanol are separated one by one; the application can simultaneously produce multiple products, has low energy consumption, high efficiency and high resource utilization rate, and meets the trend of green chemical industry and sustainable development.

Description

Technical Field

[0001] This invention relates to a continuous distillation production apparatus and method, specifically to a production apparatus and method for separating and purifying ethanol, n-butanol, and higher alcohols from a mixture generated by the catalytic conversion of bio- / coal-based ethanol to higher alcohols. Background Technology

[0002] n-Butanol is a key raw material in the industrial field with wide applications: in chemical production, it is a core raw material for manufacturing phthalic acid, aliphatic diacids, and n-butyl phosphate plasticizers; in organic synthesis, it can be used to prepare compounds such as butyraldehyde, butyric acid, and butyl lactate; it also functions as a dehydrating agent, demulsifier, and extractant for oils and pharmaceuticals; as a solvent, it can dissolve organic dyes and other substances, serving the petrochemical, food, and pharmaceutical industries. Furthermore, n-Butanol is an ideal clean fuel that can be blended with gasoline, replacing ethanol as a gasoline blending component, demonstrating significant value in the energy sector.

[0003] In the production of n-butanol, traditional methods such as acetone-butanol-ethanol fermentation and propylene carbonyl synthesis are gradually being phased out due to resource waste, high production costs, and insufficient environmental friendliness. In recent years, with the increasing maturity and scale of coal-to-ethanol and bio-fermentation ethanol production technologies, the catalytic conversion of ethanol to higher alcohols has emerged. This process, with its advantages of abundant ethanol sources, low cost, and environmental friendliness, has become a research hotspot in both academia and industry. It is worth noting that in addition to n-butanol, this process also produces hexanol, octanol, and decanol, which can be used as raw materials for the production of biofuels, plasticizers, fragrances, and cosmetics. Therefore, developing technologies for producing n-butanol clean fuels and high-value-added chemicals based on bio / coal-based ethanol is of profound significance for promoting the implementation of sustainable development strategies and ensuring national energy security.

[0004] CN 215026922 U describes a gas-liquid separation device for a n-butanol distillation system. A wire mesh separator is installed above the tank, and a liquid removal assembly is installed below to remove liquid clogging the mesh at the bottom due to excessively high gas flow rates. While this method effectively improves separation efficiency, its separation load remains high, and subsequent equipment maintenance is cumbersome and costly. CN 213202875 U describes a separation system for aqueous byproducts of Fischer-Tropsch synthesis reactions. It uses a three-tower system—a recovery tower, a dehydration tower, and a separation tower—connected together to directly separate polyol mixtures. Although this method achieves the expected separation effect, its throughput is low, making it unsuitable for separating large-volume materials, and its energy consumption is high.

[0005] This invention provides an apparatus and method for the distillation and separation of ethanol catalytic conversion to higher alcohol products that meet industrial production requirements. This apparatus and separation process combine continuous distillation, extractive distillation, and vacuum distillation, simplifying the separation process and improving separation efficiency. Furthermore, the use of partial stream reflux avoids resource waste and achieves optimal energy-saving effects. Summary of the Invention

[0006] This invention provides a production apparatus and method for the continuous distillation separation of ethanol, n-butanol, and higher alcohols. This invention enables the efficient separation of the mixture generated from the catalytic conversion of bio- / coal-based ethanol to higher alcohols, resulting in diverse products and low energy consumption, which is beneficial for industrial application.

[0007] The technical solution of the present invention is as follows:

[0008] A production apparatus for continuous distillation separation of ethanol, n-butanol and higher alcohols, comprising: a heat exchanger (13), a phase separator (14) and the following twelve distillation columns: ethyl acetate column (1), light distillation column (2), ethanol column (3), ethylene glycol column (4), n-butanol column (5), dehydration column (6), 2-ethylbutanol column (7), n-hexanol column (8), 2-ethylhexanol column (9), n-octanol column (10), 2-ethyloctanol column (11), and n-decanol column (12);

[0009] The ethyl acetate tower (1) is equipped with a feed line for inputting the mixture generated by the catalytic conversion of bio / coal-based ethanol to higher alcohols. The top discharge line of the ethyl acetate tower (1) is connected to the ethyl acetate discharge line, and the bottom discharge line is connected to the feed line of the light extraction tower (2).

[0010] The top discharge line of the light tower (2) is connected to the feed line of the ethanol tower (3), and the bottom discharge line is connected to the feed line of the 2-ethylbutanol tower (7).

[0011] The top discharge line of the ethanol tower (3) is connected to the ethanol discharge line, and the bottom discharge line is connected to the feed line of the ethylene glycol tower (4); in addition, the ethanol tower (3) is also equipped with an ethylene glycol feed line.

[0012] The top discharge line of the ethylene glycol tower (4) is connected to the feed line of the heat exchanger (13), and the bottom discharge line is connected to the ethylene glycol discharge line.

[0013] The outlet line of the heat exchanger (13) is connected to the inlet line of the phase separator (14);

[0014] The upper phase discharge line of the phase separator (14) is connected to the feed line of the n-butanol tower (5), and the lower phase discharge line is connected to the feed line of the dehydration tower (6).

[0015] The top discharge line of the n-butanol column (5) is connected to the feed line of the heat exchanger (13), and the bottom discharge line is connected to the n-butanol discharge line.

[0016] The top discharge pipeline of the dehydration tower (6) is connected to the feed pipeline of the heat exchanger (13), and the bottom discharge pipeline is connected to the liquid water discharge pipeline.

[0017] The top discharge line of the 2-ethylbutanol column (7) is connected to the 2-ethylbutanol discharge line, and the bottom discharge line is connected to the feed line of the n-hexanol column (8).

[0018] The top discharge line of the n-hexanol column (8) is connected to the n-hexanol discharge line, and the bottom discharge line is connected to the feed line of the 2-ethylhexanol column (9).

[0019] The top discharge line of the 2-ethylhexanol column (9) is connected to the 2-ethylhexanol discharge line, and the bottom discharge line is connected to the feed line of the n-octanol column (10).

[0020] The top discharge line of the n-octanol column (10) is connected to the n-octanol discharge line, and the bottom discharge line is connected to the feed line of the 2-ethyloctanol column (11).

[0021] The top discharge line of the 2-ethyl octanol column (11) is connected to the 2-ethyl octanol discharge line, and the bottom discharge line is connected to the feed line of the n-decanol column (12);

[0022] The top discharge line of the n-decyl alcohol column (12) is connected to the n-decyl alcohol discharge line, and the bottom discharge line is connected to the heavy component discharge line.

[0023] In the production apparatus of this invention,

[0024] Each distillation column is equipped with a condenser and a reboiler;

[0025] The actual process involves configuring the necessary conveying equipment according to the engineering requirements.

[0026] The present invention also relates to a production method for continuous distillation separation of ethanol, n-butanol and higher alcohols using the above-mentioned apparatus; the higher alcohols refer to: higher fatty alcohols such as 2-ethylbutanol, n-hexanol, 2-ethylhexanol, n-octanol, 2-ethyloctanol, and n-decanol;

[0027] The production method described is as follows: (In the following methods, the numbers 0' to 28' have no special meaning; they are only used to mark the different component streams in the separation system for clear description.)

[0028] (1) Light component separation

[0029] The mixture 0' generated from the catalytic conversion of bio / coal-based ethanol to higher alcohols from the catalytic reactor is fed into the ethyl acetate tower (1). The light component 1' distilled from the top of the ethyl acetate tower (1) is returned to the catalytic reactor for recycling. The bottom liquid 2' of the ethyl acetate tower (1) enters the light component tower (2). The light component 3' distilled from the top of the light component tower (2) enters the ethanol tower (3). Ethylene glycol 5', the extractant, is fed into the ethanol tower (3). Ethanol 6' is collected from the top of the ethanol tower (3) (which can be returned to the catalytic reactor for recycling). The bottom liquid 7' of the ethanol tower (3) enters the ethylene glycol tower (4). The distillate 8' from the top of the ethylene glycol tower (4) enters the heat exchanger (13). Ethylene glycol 9' is discharged from the bottom of the ethylene glycol tower (4) (which can be recycled back to the ethanol tower as an extractant for reuse).

[0030] (2) Alcohol-water separation

[0031] The distillate 8' from the top of the ethylene glycol column (4) is mixed with the distillate 13' from the top of the n-butanol column (5) and the distillate 15' from the top of the dehydration column (6). After heat exchange in the heat exchanger (13), liquid 10' enters the phase separator (14). The upper liquid 11' after separation enters the n-butanol column (5), and the lower liquid 12' enters the dehydration column (6). The distillate 13' from the top of the n-butanol column (5) is refluxed to the heat exchanger (13), and n-butanol 14' is discharged from the bottom of the n-butanol column (5). The distillate 15' from the top of the dehydration column (6) is refluxed to the heat exchanger (13), and the liquid water 16' discharged from the bottom of the dehydration column (6) is no longer used.

[0032] (3) Separation of higher alcohols

[0033] The heavy component 4' discharged from the bottom of the light column (2) enters the 2-ethylbutanol column (7). 2-Ethylbutanol 17' is collected from the top of the 2-ethylbutanol column (7). Liquid 18' discharged from the bottom of the 2-ethylbutanol column (7) enters the n-hexanol column (8). n-Hexanol 19' is collected from the top of the n-hexanol column (8). Liquid 20' discharged from the bottom of the n-hexanol column (8) enters the 2-ethylhexanol column (9). 2-Ethylhexanol 21' is collected from the top of the 2-ethylhexanol column (9). The discharged liquid 22' enters the n-octanol column (10), n-octanol 23' is collected from the top of the n-octanol column (10), the liquid 24' discharged from the bottom of the n-octanol column (10) enters the 2-ethyloctanol column (11), 2-ethyloctanol 25' is collected from the top of the 2-ethyloctanol column (11), the liquid 26' discharged from the bottom of the 2-ethyloctanol column (11) enters the n-decanol column (12), n-decanol 27' is collected from the top of the n-decanol column (12), and the liquid 28' discharged from the bottom of the n-decanol column (12) is a heavy component;

[0034] in,

[0035] The operating conditions of the ethyl acetate column (1) are as follows: operating pressure at the top of the column is 50-200 kPa, reflux ratio is 1.0-1.7, number of trays is 20-90, feed trays are 12-40, top temperature is 60-100℃, and bottom temperature is 80-120℃.

[0036] The operating conditions of the light tower (2) are as follows: the operating pressure at the top of the tower is 100-200 kPa, the reflux ratio is 0.2-0.5, the number of trays is 25-80, the feed trays are 12-35, the temperature at the top of the tower is 80-105℃, and the temperature at the bottom of the tower is 170-205℃.

[0037] The operating conditions of the ethanol tower (3) are as follows: the operating pressure at the top of the tower is 40-100 kPa, the reflux ratio is 2.4-4.9, the number of trays is 35-80, the feed trays of the material from the light extraction tower are 17-60, the feed trays of the extractant are 2-5, the temperature at the top of the tower is 55-80℃, and the temperature at the bottom of the tower is 80-105℃.

[0038] The operating conditions of the ethylene glycol tower (4) are as follows: operating pressure at the top of the tower is 10-250 kPa, reflux ratio is 0.5-10.0, number of trays is 20-100, feed trays are 10-70, top temperature is 40-120℃, and bottom temperature is 140-220℃.

[0039] The operating conditions of the n-butanol column (5) are as follows: the top operating pressure is 10-130 kPa, the reflux ratio is 0.5-8.0, the number of trays is 20-80, the feed tray is 10-50, the top temperature is 35-100℃, and the bottom temperature is 45-130℃.

[0040] The operating conditions of the dehydration tower (6) are as follows: the operating pressure at the top of the tower is 10-100 kPa, the reflux ratio is 0.5-8.0, the number of trays is 18-90, the feed trays are 6-45, the temperature at the top of the tower is 45-95℃, and the temperature at the bottom of the tower is 65-105℃.

[0041] The operating conditions of the 2-ethylbutanol column (7) are as follows: the operating pressure at the top of the column is 10-200 kPa, the reflux ratio is 7.0-20.0, the number of trays is 60-120, the feed tray is 30-75, and after being subcooled by 3-5°C in the top condenser, the temperature at the top of the column is 85-170°C, and the temperature at the bottom of the column is 125-210°C.

[0042] The operating conditions of the n-hexanol column (8) are as follows: the operating pressure at the top of the column is 10-200 kPa, the reflux ratio is 1.2-7.4, the number of trays is 30-90, the feed tray is 15-45, and after being subcooled by the top condenser by 3-5°C, the top temperature is 95-180°C and the bottom temperature is 155-240°C.

[0043] The operating conditions of the 2-ethylhexanol column (9) are as follows: the operating pressure at the top of the column is 10-200 kPa, the reflux ratio is 5.6-22.0, the number of trays is 60-150, the feed tray is 30-70, and after being subcooled by 3-5°C in the top condenser, the top temperature is 115-215°C and the bottom temperature is 160-260°C.

[0044] The operating conditions of the n-octanol column (10) are as follows: the operating pressure at the top of the column is 10-100 kPa, the reflux ratio is 1.5-3.4, the number of trays is 30-120, the feed tray is 20-50, and after being subcooled by 3-5°C in the top condenser, the temperature at the top of the column is 120-195°C, and the temperature at the bottom of the column is 185-255°C.

[0045] The operating conditions of the 2-ethyl octanol column (11) are as follows: the top operating pressure is 10-100 kPa, the reflux ratio is 8.0-19.0, the number of trays is 60-120, the feed tray is 35-90, and after being subcooled by 3-5°C in the top condenser, the top temperature is 140-230°C and the bottom temperature is 190-265°C.

[0046] The operating conditions of the n-decyl alcohol column (12) are as follows: the operating pressure at the top of the column is 10-100 kPa, the reflux ratio is 5.6-15.6, the number of trays is 30-100, the feed tray is 15-45, the temperature at the top of the column is 150-230℃ after being subcooled by the condenser at the top of the column by 3-5℃, and the temperature at the bottom of the column is 190-270℃.

[0047] The advantages of this invention are:

[0048] This invention discloses a production apparatus and method for continuous distillation separation of ethanol, n-butanol, and higher alcohols. It mainly includes three parts: a light component separation system, an alcohol-water separation system, and a higher alcohol separation system, consisting of 12 distillation columns, 1 phase separator, and 1 heat exchanger, forming a complete separation device.

[0049] In the light component separation step, the ethanol content in the top distillate of the ethyl acetate column (1) and the ethanol column (3) is relatively high and the distillate volume is large, so it can be returned to the catalytic reactor for continued recycling. The ethanol column (3) uses extractive distillation for separation, and the extract can be recycled. The above methods can significantly improve resource utilization efficiency, save energy, and greatly reduce investment costs and operating expenses.

[0050] In the alcohol-water separation step, the heat exchanger (13), phase separator (14), n-butanol column (5), and dehydration column (6) form a circulating system. The distillate from the n-butanol column (5) and the dehydration column (6) is a n-butanol-water azeotrope, which is refluxed to the heat exchanger (13) and mixed with the distillate from the ethylene glycol column (4), before entering the phase separator (14) for stratification. The above method can significantly improve the n-butanol recovery efficiency and reduce energy consumption.

[0051] In the higher alcohol separation step, the corresponding products are separated in the 2-ethylbutanol column (7), hexanol column (8), 2-ethylhexanol column (9), octanol column (10), 2-ethyloctanol column (11), and n-decanol column (12); all separations are performed using vacuum distillation. The above method greatly simplifies the product distillation process, reduces production energy consumption, and improves production efficiency.

[0052] This invention utilizes a single production unit to simultaneously produce multiple higher alcohol products, simplifying the process. Furthermore, product purity can be adjusted as needed, offering advantages such as low energy consumption, high efficiency, and product diversity compared to traditional processes. In addition, this invention introduces an alcohol-water separation and recycling system, achieving efficient separation of n-butanol and water, saving energy and reducing consumption, and meeting the requirements of green chemistry and sustainable development. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the production process of the present invention.

[0054] Among them, 1-ethyl acetate tower; 2-light weight tower; 3-ethanol tower; 4-ethylene glycol tower; 5-n-butanol tower; 6-dehydration tower; 7-2-ethylbutanol tower; 8-n-hexanol tower; 9-2-ethylhexanol tower; 10-n-octanol tower; 11-2-ethyloctanol tower; 12-n-decanol tower; 13-heat exchanger; 14-phase separator. Detailed Implementation

[0055] The present invention will now be described in detail with reference to the accompanying drawings. The embodiments described below are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0056] like Figure 1 As shown, this invention provides a separation process for ethanol, n-butanol, and higher alcohols, mainly consisting of three steps: light component separation, alcohol-water separation, and higher alcohol separation. The mixture produced from the catalytic conversion of ethanol to higher alcohols is preheated and then enters ethyl acetate column 1. Finally, n-butanol is distilled from n-butanol column 5, 2-ethylbutanol from 2-ethylbutanol column 7, n-hexanol from n-hexanol column 8, 2-ethylhexanol from 2-ethylhexanol column 9, n-octanol from n-octanol column 10, 2-ethyloctanol from 2-ethyloctanol column 11, and n-decanol from n-decanol column 12. The specific implementation flow of this production method is as follows.

[0057] The mixture produced from the catalytic reaction of ethanol to higher alcohols is preheated and then first enters the light component separation step, with the feed temperature preferably between 25 and 75°C. The mixture is then passed through ethyl acetate column 1 to separate ethyl acetate, ethanol, aldehydes, and other light components, which are distilled off from the top of column 1. Ethanol and aldehydes can be recycled back to the reactor for reuse.

[0058] The material collected from the bottom of ethyl acetate column 1 enters the light distillation column 2, where ethanol, n-butanol, water, and residual light components are mainly distilled off from the top. The distillate from the top enters the ethanol column 3 for recovery, while the liquid from the bottom flows into the 2-ethylbutanol column 7.

[0059] Ethanol column 3 obtains a high-purity ethanol product through extractive distillation, preferably extractive distillation, and the extract is preferably ethylene glycol. The ethanol product is collected from the top of the column and refluxed to the reactor for recycling. Finally, a mixed solution composed of ethylene glycol, water, butanol, and other substances with boiling points higher than ethanol is collected from the bottom of the column and connected to the feed inlet of ethylene glycol column 4.

[0060] The top outlet of the ethylene glycol column 4 is connected to the inlet of the heat exchanger 13. The top outlet enters the alcohol-water separation step, and the liquid in the bottom of the column is ethylene glycol. The heat exchanger 13 is connected to the phase separator 14. After phase separation in the phase separator 14, the aqueous phase flows out from the bottom and enters the dehydration column 6; the alcohol phase flows out from the top and enters the n-butanol column 5.

[0061] After the alcohol phase from the phase separator 14 enters the n-butanol column 5, high-purity n-butanol is separated from the bottom of the column. An azeotrope of n-butanol and water is distilled off from the top of the column and returned to the phase separator 14 for separation.

[0062] The aqueous phase from the phase separator 14 enters the dehydration tower 6 and is recovered in an azeotropic manner to remove substances such as n-butanol. The n-butanol and other substances are distilled off from the top of the tower and returned to the phase separator 14 for further separation. The bottom of the tower contains water and a small amount of water-soluble impurities, which are not reused.

[0063] The heavy alcohol mixture flowing from the bottom of the light alcohol column 2 enters the 2-ethylbutanol column 7, where 2-ethylbutanol is separated. Because C6 alcohols have isomers with very small boiling point differences, separation is difficult. Therefore, vacuum distillation is preferred for this column. The product 2-ethylbutanol is distilled from the top of the column. The number of trays, reflux ratio, feed location, and operating pressure can be adjusted according to the required product quality standards. Specifically, when the number of trays is not less than 60 and the reflux ratio is not less than 7, the product purity is >98.0 wt%. The remaining heavy alcohol mixture with more than C6 alcohols flows from the bottom of the column and is connected to the feed inlet in the middle of the n-hexanol column 8, with <0.5 wt% 2-ethylbutanol remaining in the bottom liquid.

[0064] The above-mentioned bottom liquid enters the n-hexanol column 8, where n-hexanol is separated. The n-hexanol product is distilled off from the top of the column. The number of trays, reflux ratio, feed position, and operating pressure can be adjusted according to the required product quality standards. Specifically, when the number of trays is not less than 30 and the reflux ratio is not less than 1.2, the product purity is >98.0 wt%. The remaining mixture flows out from the bottom of the column and is connected to the feed inlet in the middle of the 2-ethylhexanol column 9, with <0.5 wt% n-hexanol residue in the bottom liquid.

[0065] The above-mentioned bottom liquid enters the 2-ethylhexanol column 9, where 2-ethylhexanol is separated. Vacuum distillation is preferred for this column. The product 2-ethylhexanol is distilled from the top of the column. The number of trays, reflux ratio, feed position, and operating pressure can be adjusted according to the required product quality standards. Specifically, when the number of trays is not less than 60 and the reflux ratio is not less than 5.6, the product purity is >98.0 wt%. The remaining heavy alcohol mixture flows out from the bottom of the column and is connected to the feed inlet in the middle of the n-octanol column 10, with <0.5 wt% 2-ethylhexanol remaining in the bottom liquid.

[0066] The above-mentioned bottom liquid enters the n-octanol column 10, where n-octanol is separated. The n-octanol product is distilled off from the top of the column. The number of trays, reflux ratio, feed position, and operating pressure can be adjusted according to the required product quality standards. Specifically, when the number of trays is not less than 30 and the reflux ratio is not less than 1.5, the product purity is >98.0 wt%. The remaining heavy alcohol mixture flows out from the bottom of the column and is connected to the feed inlet in the middle of the 2-ethyloctanol column 11, with residual n-octanol in the bottom liquid <0.5 wt%.

[0067] The above-mentioned bottom liquid enters the 2-ethyloctanol column 11, where 2-ethyloctanol is separated. The 2-ethyloctanol product is distilled off from the top of the column. The number of trays, reflux ratio, feed position, and operating pressure can be adjusted according to the required product quality standards. Specifically, when the number of trays is not less than 60 and the reflux ratio is not less than 8, the product purity is >98.0 wt%. The remaining heavy alcohol mixture flows out from the bottom of the column and is connected to the feed inlet in the middle of the n-decanol column 12. The residual 2-ethyloctanol in the bottom liquid is <0.5 wt%.

[0068] The liquid from the bottom of the 2-ethyloctanol column 11 enters the n-decanol column 12, where n-decanol is separated. The n-decanol product is distilled off from the top of the column. The number of trays, reflux ratio, feed location, and operating pressure can be adjusted according to the required product quality standards. Specifically, when the number of trays is not less than 30 and the reflux ratio is not less than 5.6, the product purity is >98.0 wt%. The remaining heavy alcohol mixture flows out from the bottom of the column.

[0069] This invention involves preheating the mixture generated from the catalytic conversion of bio-based / coal-based ethanol to higher alcohols, then removing light components through a light component separation step, removing most of the water and separating n-butanol through an alcohol-water separation step, and finally separating the C6-C6 components. 10Alcohols are separated one-to-one to obtain various higher alcohol products. This method simplifies the production process, improves production efficiency, makes efficient use of energy, and reduces production costs.

[0070] To further understand the production process involved in this invention, the following two specific embodiments will be used to describe a method for the continuous distillation separation of ethanol, n-butanol and higher alcohols.

[0071] In the following examples, the mixture generated from the catalytic conversion of bio / coal-based ethanol to higher alcohols in the catalytic reactor was used as the initial material, and its composition is shown in Table 1. The catalytic conversion of bio / coal-based ethanol to higher alcohols is a known technology in the art (CN 113443964 A; CN 115814805 A; CN 117645528 A; CN 119215910 B; CN113332989 A; CN 119869537 A; CN 119857488 A).

[0072] Example 1

[0073] Separation processes such as Figure 1 As shown in Table 1, the initial material 0' entering ethyl acetate tower 1 has a flow rate of 1000 kg / h, is preheated to 45℃, and has a pressure of 200 kPa. The composition of the initial material is shown in Table 1 below.

[0074] Table 1. Composition of feed material for ethyl acetate tower 1

[0075]

[0076] As described in the specific embodiments above, the material undergoes light component separation, alcohol-water separation, and higher alcohol separation steps to obtain various higher alcohol products such as n-butanol, 2-ethylbutanol, n-hexanol, 2-ethylhexanol, n-octanol, 2-ethyloctanol, and n-decanol. The following are specific implementation data for each part; all distillation columns described below are equipped with condensers and reboilers.

[0077] The light component separation step includes ethyl acetate column 1, light component distillation column 2, ethanol column 3, and ethylene glycol column 4. The material first enters ethyl acetate column 1 for rectification. Subsequently, the bottom liquid from ethyl acetate column 1 enters light component distillation column 2; the distillate from light component distillation column 2 enters ethanol column 3; the bottom liquid from light component distillation column 2 enters 2-ethylbutanol column 7; the bottom liquid from ethanol column 3 enters ethylene glycol column 4; and the distillate from ethylene glycol column 4 enters the alcohol-water separation step.

[0078] The parameters of each stream are shown in Table 2 below. The overhead stream of ethyl acetate tower 1 is stream 1'; the bottom stream of ethyl acetate tower 1 is stream 2'; the overhead stream of light removal tower 2 is stream 3'; the bottom stream of light removal tower 2 is stream 4'; the extractant feed stream of ethanol tower 3 is stream 5'; the overhead stream of ethanol tower 3 is stream 6'; the bottom stream of ethanol tower 3 is stream 7'; the overhead stream of ethylene glycol tower 4 is stream 8'; and the bottom stream of ethylene glycol tower 4 is stream 9'.

[0079] Table 2 Parameters of each stream in the light component separation system

[0080]

[0081]

[0082] The specific parameters of each tower are shown in Table 3 below.

[0083] Table 3 Specific parameters of each column in the light component separation system

[0084]

[0085] The reboiler load of the ethyl acetate tower 1 is 248kW; the condenser load is -120kW.

[0086] The reboiler load of the light tower 2 is 159kW; the condenser load is -148kW.

[0087] The reboiler load of the ethanol tower 3 is 215kW; the condenser load is -215kW.

[0088] The reboiler load of the ethylene glycol tower 4 is 187kW; the condenser load is -170kW.

[0089] The equipment for the alcohol-water separation step includes a phase separator 14, a heat exchanger 13, a n-butanol column 5, and a dehydration column 6. Since water is partially soluble in n-butanol, the phase separator 14 is used for phase separation. Before phase separation, the distillate from the ethylene glycol column 4 enters the heat exchanger 13 to be cooled and pressurized to the minimum solubility conditions of water in butanol to achieve optimal phase separation. The alcohol phase from the upper outlet of the phase separator 14 enters the n-butanol column 5 to separate n-butanol; the water layer from the lower outlet enters the dehydration column 6 to remove water and some impurities. Furthermore, the distillate from the n-butanol column 5 and the distillate from the dehydration column 6 are returned to the phase separator 14 for further phase separation.

[0090] The parameters of each stream are shown in Table 4 below. The stream at the outlet of heat exchanger 13 is stream 10'; the stream at the upper outlet of phase separator 14 is stream 11'; the stream at the lower outlet of phase separator 14 is stream 12'; the stream at the top of n-butanol column 5 is stream 13'; the stream at the bottom of n-butanol column 5 is stream 14'; the stream at the top of dehydration column 6 is stream 15'; and the stream at the bottom of dehydration column 6 is stream 16'.

[0091] Table 4 Parameters of each stream in the oil-water phase separation system

[0092]

[0093] The specific parameters of each tower are shown in Table 5 below.

[0094] Table 5 Specific parameters of each tower in the oil-water phase separation system

[0095]

[0096] The reboiler load of the n-butanol column 5 is 211kW; the condenser load is -184kW.

[0097] The dehydration tower 6 has a reboiler load of 53kW and a condenser load of -44kW.

[0098] The higher alcohol separation steps include 2-ethylbutanol column 7, n-hexanol column 8, 2-ethylhexanol column 9, n-octanol column 10, 2-ethyloctanol column 11, and n-decanol column 12. The bottom liquid from column 2 of the above-mentioned light alcohol separation unit enters 2-ethylbutanol column 7; the bottom liquid from 2-ethylbutanol column 7 enters n-hexanol column 8; the bottom liquid from n-hexanol column 8 enters 2-ethylhexanol column 9; the bottom liquid from 2-ethylhexanol column 9 enters n-octanol column 10; the bottom liquid from n-octanol column 10 enters 2-ethyloctanol column 11; and the bottom liquid from 2-ethyloctanol column 11 enters n-decanol column 12. Finally, the 2-ethylbutanol product was collected from the top of column 7 of the 2-ethylbutanol column; the n-hexanol product was collected from the top of column 8 of the n-hexanol column; the 2-ethylhexanol product was collected from the top of column 9 of the 2-ethylhexanol column; the n-octanol product was collected from the top of column 10 of the n-octanol column; the 2-ethyloctanol product was collected from the top of column 11 of the 2-ethyloctanol column; and the n-decanol product was collected from the top of column 12 of the n-decanol column.

[0099] The parameters of each stream are shown in Tables 6-1 and 6-2 below. The overhead stream (5°C subcooled condenser) of 2-ethylbutanol column 7 is stream 17'; the bottom stream of 2-ethylbutanol column 7 is stream 18'; the overhead stream (5°C subcooled condenser) of n-hexanol column 8 is stream 19'; the bottom stream of n-hexanol column 8 is stream 20'; the overhead stream (5°C subcooled condenser) of 2-ethylhexanol column 9 is stream 21'; and the bottom stream of 2-ethylhexanol column 9 is stream 22'. The overhead stream of n-octanol column 10 (with a 5°C subcooling condenser at the top) is stream 23'; the bottom stream of n-octanol column 10 is stream 24'; the overhead stream of 2-ethyloctanol column 11 (with a 5°C subcooling condenser at the top) is stream 25'; the bottom stream of 2-ethyloctanol column 11 is stream 26'; the overhead stream of n-decanol column 12 (with a 5°C subcooling condenser at the top) is stream 27'; and the bottom stream of n-decanol column 12 is stream 28'.

[0100] Table 6-1 Parameters of each stream in the higher alcohol separation system

[0101]

[0102] Table 6-2 Parameters of each stream in the higher alcohol separation system

[0103]

[0104] The specific parameters of each tower are shown in Table 7 below.

[0105] Table 7 Specific parameters of each column in the advanced alcohol separation system

[0106]

[0107] The reboiler load of the 2-ethylbutanol column 7 is 108kW; the condenser load is -109kW.

[0108] The reboiler load of the n-hexanol column 8 is 27kW; the condenser load is -26kW.

[0109] The 2-ethylhexanol column 9 has a reboiler load of 40kW and a condenser load of -38kW.

[0110] The reboiler load of the n-octanol column 10 is 7kW; the condenser load is -9kW.

[0111] The 2-ethyloctyl alcohol column 11 has a reboiler load of 10kW and a condenser load of -11kW.

[0112] The reboiler load of the n-decyl alcohol column 12 is 8kW; the condenser load is -8kW.

[0113] In the above process, the liquid produced by stream 16' and stream 28' can be recovered.

[0114] Example 2

[0115] Separation processes such as Figure 1 As shown in Table 8, the initial material 0' entering the ethyl acetate tower 1 has a flow rate of 1100 kg / h, is preheated to 50°C, and has a pressure of 200 kPa. The composition of the initial material is shown in Table 8 below.

[0116] Table 8. Composition of feed material for ethyl acetate tower 1

[0117]

[0118] As described in the specific implementation method above, the materials undergo light component separation, alcohol-water separation, and higher alcohol separation steps to obtain n-butanol, 2-ethylbutanol, n-hexanol, 2-ethylhexanol, n-octanol, 2-ethyloctanol, and n-decanol products, respectively. The following are specific implementation data for each part; all distillation columns described below are equipped with condensers and reboilers.

[0119] The parameters of each stream are shown in Table 9 below. The overhead stream of ethyl acetate tower 1 is stream 1'; the bottom stream of ethyl acetate tower 1 is stream 2'; the overhead stream of light removal tower 2 is stream 3'; the bottom stream of light removal tower 2 is stream 4'; the extractant feed stream of ethanol tower 3 is stream 5'; the overhead stream of ethanol tower 3 is stream 6'; the bottom stream of ethanol tower 3 is stream 7'; the overhead stream of ethylene glycol tower 4 is stream 8'; and the bottom stream of ethylene glycol tower 4 is stream 9'.

[0120] Table 9 Parameters of each stream in the light component separation system

[0121]

[0122]

[0123] The specific parameters of each tower are shown in Table 10 below.

[0124] Table 10 Specific parameters of each column in the light component separation system

[0125]

[0126] The reboiler load of the ethyl acetate tower 1 is 263kW; the condenser load is -124kW.

[0127] The reboiler load of the light tower 2 is 161kW; the condenser load is -149kW.

[0128] The reboiler load of the ethanol tower 3 is 141kW; the condenser load is -142kW.

[0129] The reboiler load of the ethylene glycol tower 4 is 153kW; the condenser load is -135kW.

[0130] The parameters of each stream in the alcohol-water separation step are shown in Table 11 below. The stream at the outlet of heat exchanger 13 is stream 10'; the stream at the upper outlet of phase separator 14 is stream 11'; the stream at the lower outlet of phase separator 14 is stream 12'; the stream at the top of n-butanol column 5 is stream 13'; the stream at the bottom of n-butanol column 5 is stream 14'; the stream at the top of dehydration column 6 is stream 15'; and the stream at the bottom of dehydration column 6 is stream 16'.

[0131] Table 11 Parameters of each stream in the oil-water phase separation system

[0132]

[0133] The specific parameters of each tower are shown in Table 12 below.

[0134] Table 12 Specific parameters of each column in the oil-water phase separation system

[0135]

[0136] The reboiler load of the n-butanol column 5 is 237kW; the condenser load is -209kW.

[0137] The dehydration tower 6 has a reboiler load of 63kW and a condenser load of -53kW.

[0138] The parameters of each stream in the higher alcohol separation step are shown in Tables 13-1 and 13-2 below. The overhead stream (5°C subcooled by the overhead condenser) of 2-ethylbutanol column 7 is stream 17'; the bottom stream of 2-ethylbutanol column 7 is stream 18'; the overhead stream (5°C subcooled by the overhead condenser) of n-hexanol column 8 is stream 19'; the bottom stream of n-hexanol column 8 is stream 20'; the overhead stream (5°C subcooled by the overhead condenser) of 2-ethylhexanol column 9 is stream 21'; and the bottom stream of 2-ethylhexanol column 9 is stream 22'. The overhead stream of n-octanol column 10 (with a 5°C subcooling condenser at the top) is stream 23'; the bottom stream of n-octanol column 10 is stream 24'; the overhead stream of 2-ethyloctanol column 11 (with a 5°C subcooling condenser at the top) is stream 25'; the bottom stream of 2-ethyloctanol column 11 is stream 26'; the overhead stream of n-decanol column 12 (with a 5°C subcooling condenser at the top) is stream 27'; and the bottom stream of n-decanol column 12 is stream 28'.

[0139] Table 13-1 Parameters of each stream in the higher alcohol separation system

[0140]

[0141] Table 13-2 Parameters of each stream in the higher alcohol separation system

[0142]

[0143] The specific parameters of each tower are shown in Table 14 below.

[0144] Table 14 Specific parameters of each column in the advanced alcohol separation system

[0145]

[0146] The reboiler load of the 2-ethylbutanol column 7 is 82kW; the condenser load is -85kW.

[0147] The reboiler load of the n-hexanol column 8 is 31kW; the condenser load is -27kW.

[0148] The 2-ethylhexanol column 9 has a reboiler load of 26kW and a condenser load of -26kW.

[0149] The reboiler load of the n-octanol column 10 is 8kW; the condenser load is -10kW.

[0150] The 2-ethyloctanol column 11 has a reboiler load of 17kW and a condenser load of -21kW.

[0151] The reboiler load of the n-decyl alcohol column 12 is 8kW; the condenser load is -8kW.

[0152] In the above process, the liquid produced by stream 16' and stream 28' can be recovered.

[0153] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention to other forms. Any person skilled in the art may modify or improve the technical content shown above. Any simple modifications and improvements made to the above embodiments based on the technical essence of the present invention without departing from the concept of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A production apparatus for continuous distillation separation of ethanol, n-butanol, and higher alcohols, characterized in that, The apparatus includes: a heat exchanger (13), a phase separator (14), and the following twelve distillation columns: ethyl acetate column (1), light distillation column (2), ethanol column (3), ethylene glycol column (4), n-butanol column (5), dehydration column (6), 2-ethylbutanol column (7), n-hexanol column (8), 2-ethylhexanol column (9), n-octanol column (10), 2-ethyloctanol column (11), and n-decanol column (12); The ethyl acetate tower (1) is equipped with a feed line for inputting the mixture generated by the catalytic conversion of bio / coal-based ethanol to higher alcohols. The top discharge line of the ethyl acetate tower (1) is connected to the ethyl acetate discharge line, and the bottom discharge line is connected to the feed line of the light extraction tower (2). The top discharge line of the light tower (2) is connected to the feed line of the ethanol tower (3), and the bottom discharge line is connected to the feed line of the 2-ethylbutanol tower (7). The top discharge line of the ethanol tower (3) is connected to the ethanol discharge line, and the bottom discharge line is connected to the feed line of the ethylene glycol tower (4); in addition, the ethanol tower (3) is also equipped with an ethylene glycol feed line. The top discharge line of the ethylene glycol tower (4) is connected to the feed line of the heat exchanger (13), and the bottom discharge line is connected to the ethylene glycol discharge line. The outlet line of the heat exchanger (13) is connected to the inlet line of the phase separator (14); The upper phase discharge line of the phase separator (14) is connected to the feed line of the n-butanol tower (5), and the lower phase discharge line is connected to the feed line of the dehydration tower (6). The top discharge line of the n-butanol column (5) is connected to the feed line of the heat exchanger (13), and the bottom discharge line is connected to the n-butanol discharge line. The top discharge pipeline of the dehydration tower (6) is connected to the feed pipeline of the heat exchanger (13), and the bottom discharge pipeline is connected to the liquid water discharge pipeline. The top discharge line of the 2-ethylbutanol column (7) is connected to the 2-ethylbutanol discharge line, and the bottom discharge line is connected to the feed line of the n-hexanol column (8). The top discharge line of the n-hexanol column (8) is connected to the n-hexanol discharge line, and the bottom discharge line is connected to the feed line of the 2-ethylhexanol column (9). The top discharge line of the 2-ethylhexanol column (9) is connected to the 2-ethylhexanol discharge line, and the bottom discharge line is connected to the feed line of the n-octanol column (10). The top discharge line of the n-octanol column (10) is connected to the n-octanol discharge line, and the bottom discharge line is connected to the feed line of the 2-ethyloctanol column (11). The top discharge line of the 2-ethyl octanol column (11) is connected to the 2-ethyl octanol discharge line, and the bottom discharge line is connected to the feed line of the n-decanol column (12); The top discharge line of the n-decyl alcohol column (12) is connected to the n-decyl alcohol discharge line, and the bottom discharge line is connected to the heavy component discharge line.

2. A method for producing ethanol, n-butanol, and higher alcohols by continuous distillation separation using the apparatus described in claim 1; wherein the higher alcohols refer to: 2-ethylbutanol, n-hexanol, 2-ethylhexanol, n-octanol, 2-ethyloctanol, and n-decanol; characterized in that: The production method is as follows: In the following methods, the numbers 0' to 28' have no special meaning; they are simply used to mark the different component streams in the separation system for clear description. (1) Light component separation The mixture 0' generated from the catalytic conversion of bio / coal-based ethanol to higher alcohols from the catalytic reactor is fed into the ethyl acetate tower (1). The light component 1' distilled from the top of the ethyl acetate tower (1) is returned to the catalytic reactor for recycling. The bottom liquid 2' of the ethyl acetate tower (1) enters the light component extraction tower (2). The light component 3' distilled from the top of the light component extraction tower (2) enters the ethanol tower (3). Ethylene glycol 5' is added as an extractant to the ethanol tower (3). Ethanol 6' is collected from the top of the ethanol tower (3). The bottom liquid 7' of the ethanol tower (3) enters the ethylene glycol tower (4). The top distillate 8' of the ethylene glycol tower (4) enters the heat exchanger (13). Ethylene glycol 9' is discharged from the bottom of the ethylene glycol tower (4). (2) Alcohol-water separation The distillate 8' from the top of the ethylene glycol column (4) is mixed with the distillate 13' from the top of the n-butanol column (5) and the distillate 15' from the top of the dehydration column (6). After heat exchange in the heat exchanger (13), liquid 10' enters the phase separator (14). The upper liquid 11' after separation enters the n-butanol column (5), and the lower liquid 12' enters the dehydration column (6). The distillate 13' from the top of the n-butanol column (5) is refluxed to the heat exchanger (13), and n-butanol 14' is discharged from the bottom of the n-butanol column (5). The distillate 15' from the top of the dehydration column (6) is refluxed to the heat exchanger (13), and the liquid water 16' discharged from the bottom of the dehydration column (6) is no longer used. (3) Separation of higher alcohols The heavy component 4' discharged from the bottom of the light column (2) enters the 2-ethylbutanol column (7). 2-Ethylbutanol 17' is collected from the top of the 2-ethylbutanol column (7). Liquid 18' discharged from the bottom of the 2-ethylbutanol column (7) enters the n-hexanol column (8). n-Hexanol 19' is collected from the top of the n-hexanol column (8). Liquid 20' discharged from the bottom of the n-hexanol column (8) enters the 2-ethylhexanol column (9). 2-Ethylhexanol 21' is collected from the top of the 2-ethylhexanol column (9). The discharged liquid 22' enters the n-octanol column (10), n-octanol 23' is collected from the top of the n-octanol column (10), the discharged liquid 24' from the bottom of the n-octanol column (10) enters the 2-ethyloctanol column (11), 2-ethyloctanol 25' is collected from the top of the 2-ethyloctanol column (11), the discharged liquid 26' from the bottom of the 2-ethyloctanol column (11) enters the n-decanol column (12), n-decanol 27' is collected from the top of the n-decanol column (12), and the discharged liquid 28' from the bottom of the n-decanol column (12) is a heavy component.

3. The production method as described in claim 2, characterized in that, In the light component separation step: The operating conditions of the ethyl acetate column (1) are as follows: operating pressure at the top of the column is 50-200 kPa, reflux ratio is 1.0-1.7, number of trays is 20-90, feed trays are 12-40, top temperature is 60-100℃, and bottom temperature is 80-120℃. The operating conditions of the light tower (2) are as follows: the operating pressure at the top of the tower is 100-200 kPa, the reflux ratio is 0.2-0.5, the number of trays is 25-80, the feed trays are 12-35, the temperature at the top of the tower is 80-105℃, and the temperature at the bottom of the tower is 170-205℃. The operating conditions of the ethanol tower (3) are as follows: the operating pressure at the top of the tower is 40-100 kPa, the reflux ratio is 2.4-4.9, the number of trays is 35-80, the feed trays of the material from the light extraction tower are 17-60, the feed trays of the extractant are 2-5, the temperature at the top of the tower is 55-80℃, and the temperature at the bottom of the tower is 80-105℃. The operating conditions of the ethylene glycol tower (4) are as follows: operating pressure at the top of the tower is 10-250 kPa, reflux ratio is 0.5-10.0, number of trays is 20-100, feed trays are 10-70, top temperature is 40-120℃, and bottom temperature is 140-220℃.

4. The production method as described in claim 2, characterized in that, In the alcohol-water separation step: The operating conditions of the n-butanol column (5) are as follows: the top operating pressure is 10-130 kPa, the reflux ratio is 0.5-8.0, the number of trays is 20-80, the feed tray is 10-50, the top temperature is 35-100℃, and the bottom temperature is 45-130℃. The operating conditions of the dehydration tower (6) are as follows: operating pressure at the top of the tower is 10-100 kPa, reflux ratio is 0.5-8.0, number of trays is 18-90, feed trays are 6-45, top temperature is 45-95℃, and bottom temperature is 65-105℃.

5. The production method as described in claim 2, characterized in that, In the higher alcohol separation step: The operating conditions of the 2-ethylbutanol column (7) are as follows: the operating pressure at the top of the column is 10-200 kPa, the reflux ratio is 7.0-20.0, the number of trays is 60-120, the feed tray is 30-75, and after being subcooled by 3-5°C in the top condenser, the temperature at the top of the column is 85-170°C, and the temperature at the bottom of the column is 125-210°C. The operating conditions of the n-hexanol column (8) are as follows: the operating pressure at the top of the column is 10-200 kPa, the reflux ratio is 1.2-7.4, the number of trays is 30-90, the feed tray is 15-45, and after being subcooled by the top condenser by 3-5°C, the top temperature is 95-180°C and the bottom temperature is 155-240°C. The operating conditions of the 2-ethylhexanol column (9) are as follows: the operating pressure at the top of the column is 10-200 kPa, the reflux ratio is 5.6-22.0, the number of trays is 60-150, the feed tray is 30-70, and after being subcooled by 3-5°C in the top condenser, the top temperature is 115-215°C and the bottom temperature is 160-260°C. The operating conditions of the n-octanol column (10) are as follows: the operating pressure at the top of the column is 10-100 kPa, the reflux ratio is 1.5-3.4, the number of trays is 30-120, the feed tray is 20-50, and after being subcooled by 3-5°C in the top condenser, the temperature at the top of the column is 120-195°C, and the temperature at the bottom of the column is 185-255°C. The operating conditions of the 2-ethyl octanol column (11) are as follows: the top operating pressure is 10-100 kPa, the reflux ratio is 8.0-19.0, the number of trays is 60-120, the feed tray is 35-90, and after being subcooled by 3-5°C in the top condenser, the top temperature is 140-230°C and the bottom temperature is 190-265°C. The operating conditions of the n-decyl alcohol column (12) are as follows: the operating pressure at the top of the column is 10-100 kPa, the reflux ratio is 5.6-15.6, the number of trays is 30-100, the feed tray is 15-45, the temperature at the top of the column is 150-230℃ after being subcooled by the condenser at the top of the column by 3-5℃, and the temperature at the bottom of the column is 190-270℃.

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