Butanol production apparatus and three-effect rectification method

Abstract

The application discloses a butanol and octanol production device and a three-effect rectification method. The device comprises two processes of butanol separation and octanol separation. The two processes use the same raw material, and respectively obtain n-butanol, iso-butanol and octanol products through different processes. The butanol separation process comprises three parts of hydrogenation, light and heavy component removal and n-iso butanol separation in sequence. The octanol separation process comprises three parts of n-iso butanol separation, hydrogenation and light and heavy component removal in sequence. The light and heavy component removal part of the butanol separation process is completed by a butanol pre-rectification tower and a butanol rectification tower. The n-iso butanol separation part of the butanol separation process is completed by a butanol isomer one tower and a butanol isomer two tower. The n-iso butanol separation part of the octanol separation process is completed by a butyraldehyde isomer one tower and a butyraldehyde isomer two tower. The light and heavy component removal part of the octanol separation process is completed by an octanol pre-rectification tower and an octanol rectification tower. The mixture of n-iso butyraldehyde is used as the raw material to enter the butanol separation process and / or the octanol separation process. The application has lower energy consumption, realizes heat exchange between towers, and greatly reduces production cost.

Description

Technical Field

[0001] This invention relates to a butanol and octanol production equipment and a triple-effect distillation method. Background Technology

[0002] Butanol and octanol can be produced in the same facility using similar synthetic methods, hence the common name "butanol-octanol." Butanol and octanol are important raw materials for synthesizing fine chemical products, mainly used in the production of plasticizers, solvents, dehydrating agents, defoamers, dispersants, flotation agents, petroleum additives, and synthetic fragrances. Downstream consumption of butanol primarily includes butyl acrylate, butyl acetate, and DBP. Downstream consumption of octanol primarily includes DOP, DOTP, and octyl acrylate.

[0003] Butanol and octanol have developed rapidly with the advancement of petrochemical, polyvinyl chloride (PVC) materials, and carbonyl synthesis technologies. The main industrial production methods for butanol and octanol include acetaldehyde condensation, fermentation, the Ziegler process, and carbonyl synthesis, with carbonyl synthesis currently being the most important technology for butanol production.

[0004] The process of propylene carbonyl synthesis to produce butanol and octanol is as follows: (1) Propylene hydroformylation reaction, crude aldehyde is purified to obtain n-butyraldehyde and isobutyraldehyde; (2) n-butyraldehyde and isobutyraldehyde are hydrogenated to obtain n-butanol and isobutanol; (3) n-butyraldehyde is condensed and hydrogenated to obtain octanol. Propylene carbonyl synthesis is divided into high pressure method, medium pressure method and low pressure method. Low pressure carbonyl synthesis using Davy technology to produce butanol and octanol is a new process that was industrialized in the mid-1970s. It is a new technology jointly developed by Union Carbide Corporation of the United States, Davy Company of the United Kingdom and Johnson & Mather Company of the United Kingdom. Subsequently, Union Carbide and Davy Company developed the fourth-generation low pressure liquid phase carbonyl synthesis process "UCC / Davy MK-IV".

[0005] Low-pressure butanol and octanol technology is a low-pressure carbonyl process for producing n- and isobutyraldehyde using propylene and syngas (a mixture of hydrogen and carbon monoxide). For over 30 years, Davy Process Technology has jointly marketed and provided technology transfer and services for low-pressure butanol and octanol technology with Dow Chemical Company; to date, this technology has been transferred to 29 projects in 15 countries and regions across four continents. Low-pressure butanol and octanol technology is considered the world's leading transferable butanol and octanol technology, accounting for over 85% of global butanol and octanol production via technology transfer and using propylene as a feedstock.

[0006] Low-pressure butanol and octanol technology has obvious advantages in each reaction stage, but subsequent separation processes such as butyraldehyde separation, butanol separation, and octanol separation have high operating temperatures in each tower, large temperature differences between individual towers, and no heat exchange between them, resulting in high energy consumption. Therefore, it is necessary to improve the technology of subsequent separation processes to save energy.

[0007] The butanol and octanol unit produces butanol and octanol through distillation of the reaction liquid. Most existing production units employ separate processes for removing light and heavy components and separating positive and isomers. The heat sources and refrigerants used are all external utilities, and there is no heat exchange between the towers, resulting in high energy consumption and consequently high production costs. Therefore, reducing energy consumption has become a key focus for process improvement. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the technical problem this invention aims to solve is to provide a butanol and octanol production equipment and a triple-effect distillation method. This method consumes less energy, achieves heat exchange between the distillation columns, and significantly reduces production costs.

[0009] The technical solution adopted by the present invention to solve the aforementioned technical problem is as follows:

[0010] In a first aspect, the present invention provides a butanol and octanol production equipment, the equipment comprising a butanol pre-distillation column 2, a butanol distillation column 8, a butanol isomer first column 14, a butanol isomer second column 20, a butanol isomer first column 25, a butanol isomer second column 31, an octanol pre-distillation column 38, and an octanol distillation column 44, totaling 8 columns, each equipped with a corresponding condenser, reflux phase separator and reboiler;

[0011] The feed inlet of the butanol pre-distillation column 2 is connected to the discharge of the butanol reaction system 1;

[0012] The bottom feed of the butanol pre-distillation column 2 is connected to the feed of the butanol distillation column 8, and the top of the butanol pre-distillation column 2 is refluxed and collected as a light component.

[0013] The heavy component is collected from the bottom of the butanol distillation column 8, and the vapor phase at the top of the column is connected to the heat exchange inlet of the reboiler at the bottom of the butanol isomer secondary column 20. The heat exchange outlet of the reboiler at the bottom of the butanol isomer secondary column 20 is connected to the reflux phase separator set at the top of the butanol distillation column 8 for reflux. At the same time, the reflux material at the top of the butanol distillation column 8 is connected to the feed inlet of the butanol pre-distillation column 2 through a pipeline.

[0014] The side outlet of the butanol distillation column 8 is connected to the butanol isomer first column 14 and the butanol isomer second column 20, respectively.

[0015] The reboiler of the butanol isomer tower 14 is connected to the top of the butanol isomer tower 20 for heat exchange, and n-butanol is extracted from both the bottom of the butanol isomer tower 14 and the bottom of the butanol isomer tower 20.

[0016] A portion of the material refluxed from the top of the butanol isomer tower 14 is connected to the top inlet of the butanol isomer tower 14 via a pipeline, while the other portion is extracted as isobutanol.

[0017] A portion of the material refluxed from the top of the butanol isomer secondary column 20 is connected to the top inlet of the butanol isomer secondary column via a pipeline, while the other portion is collected as isobutanol.

[0018] The feed for both the butyraldehyde isomer tower 25 and the butyraldehyde isomer tower 31 is a mixture of butyraldehyde from the propylene carbonylation reaction. The reflux effluent from the top of the butyraldehyde isomer tower 25 and the butyraldehyde isomer tower 31 is isobutyraldehyde or a mixture of butyraldehyde, or it can be connected to the feed inlet of the butanol reaction system 1.

[0019] The reboiler of the butyraldehyde isomer first tower 25 exchanges heat with the top of the butyraldehyde isomer second tower 31, and the bottom of the butyraldehyde isomer first tower 25 and the bottom of the butyraldehyde isomer second tower 31 are connected to the inlet of the octanol pre-distillation tower 38 after passing through the octanol reaction system 37.

[0020] The bottom reboiler of the butyraldehyde isomer secondary column 31 exchanges heat with the top of the octanol distillation column;

[0021] A portion of the material refluxed from the top of the octanol pre-distillation column 38 is connected to the top inlet of the octanol pre-distillation column 38 via a pipeline, while the other portion is collected as a light component.

[0022] The bottom outlet of the octanol pre-distillation column 38 is connected to the inlet of the octanol distillation column 44; the bottom of the octanol distillation column collects heavy components, and the top of the column is condensed and refluxed to collect octanol.

[0023] Furthermore, the butyraldehyde isomer secondary tower 31 is equipped with two reboilers connected in parallel: one is the first reboiler 32 of the butyraldehyde isomer secondary tower, which uses steam as the heat source; the other is the second reboiler 33 of the butyraldehyde isomer secondary tower, which uses the top gas phase of the octanol distillation column as the heat source; the feed of the butanol reaction system is mixed butyraldehyde from the propylene carbonylation reaction.

[0024] Secondly, the present invention provides a butanol separation device, which includes a butanol pre-distillation column 2, a butanol distillation column 8, a butanol isomer first column 14, and a butanol isomer second column 20, each column being equipped with a corresponding condenser, reflux phase separator and reboiler.

[0025] The feed inlet of the butanol pre-distillation column 2 is connected to the output of the butanol reaction system 1, and the main component of the output is mixed butanol;

[0026] The bottom feed of the butanol pre-distillation column 2 is connected to the feed of the butanol distillation column 8, and the top of the butanol pre-distillation column 2 is refluxed and collected as a light component.

[0027] The heavy component is collected from the bottom of the butanol distillation column 8, and the vapor phase at the top of the column is connected to the heat exchange inlet of the reboiler at the bottom of the butanol isomer secondary column 20. The heat exchange outlet of the reboiler at the bottom of the butanol isomer secondary column 20 is connected to the reflux phase separator set at the top of the butanol distillation column 8 for reflux. At the same time, the reflux material at the top of the butanol distillation column 8 is connected to the feed inlet of the butanol pre-distillation column 2 through a pipeline.

[0028] The side outlet of the butanol distillation column 8 is connected to the butanol isomer first column 14 and the butanol isomer second column 20, respectively.

[0029] The reboiler of the butanol isomer tower 14 is connected to the top of the butanol isomer tower 20 for heat exchange, and n-butanol is extracted from both the bottom of the butanol isomer tower 14 and the bottom of the butanol isomer tower 20.

[0030] A portion of the material refluxed from the top of the butanol isomer tower 14 is connected to the top inlet of the butanol isomer tower 14 via a pipeline, while the other portion is extracted as isobutanol.

[0031] A portion of the material refluxed from the top of the butanol isomer secondary column 20 is connected to the top inlet of the butanol isomer secondary column via a pipeline, while the other portion is extracted as isobutanol.

[0032] Thirdly, the present invention provides an octanol separation device, which includes a butyraldehyde isomer first column 25, a butyraldehyde isomer second column 31, an octanol pre-distillation column 38, and an octanol distillation column 44.

[0033] The feed for both the butyraldehyde isomer tower 25 and the butyraldehyde isomer tower 31 is a mixture of butyraldehyde from the propylene carbonylation reaction, and the reflux effluent from the top of the towers is isobutyraldehyde or a mixture of butyraldehyde.

[0034] The reboiler of the butyraldehyde isomer first tower 25 exchanges heat with the top of the butyraldehyde isomer second tower 31, and the bottom of the butyraldehyde isomer first tower 25 and the bottom of the butyraldehyde isomer second tower 31 are connected to the inlet of the octanol pre-distillation tower 38 after passing through the octanol reaction system 37.

[0035] The bottom reboiler of the butyraldehyde isomer secondary column 31 exchanges heat with the top of the octanol distillation column;

[0036] A portion of the material refluxed from the top of the octanol pre-distillation column 38 is connected to the top inlet of the octanol pre-distillation column 38 via a pipeline, while the other portion is collected as a light component.

[0037] The bottom outlet of the octanol pre-distillation column 38 is connected to the inlet of the octanol distillation column 44; the bottom of the octanol distillation column collects heavy components, and the top of the column is condensed and refluxed to collect octanol.

[0038] Fourthly, this invention provides a three-effect distillation method for the production of butanol and octanol, comprising two processes: butanol separation and octanol separation. Both processes use the same raw materials and obtain n-butanol, isobutanol, and octanol products through different steps. The butanol separation is divided into three parts in sequence: hydrogenation, removal of light and heavy components, and separation of n-isomers. The octanol separation can be divided into three parts in sequence: separation of n-isomers, hydrogenation, and removal of light and heavy components.

[0039] The butanol de-light and de-heavy fraction is completed by butanol pre-distillation column 2 and butanol distillation column 8; the butanol isomerization separation fraction is completed by butanol isomer first column 14 and butanol isomer second column 20; the octanol isomerization separation fraction is completed by butyraldehyde isomer first column 25 and butyraldehyde isomer second column 31; the octanol de-light and de-heavy fraction is completed by octanol pre-distillation column 38 and octanol distillation column 44.

[0040] A mixture of n- and isobutyraldehyde is used as a raw material in the butanol separation process and / or octanol separation process;

[0041] In the butanol separation process, the mixture of n- and isobutyraldehyde is hydrogenated to obtain a mixture of n- and isobutanol, i.e., crude butanol. The crude butanol first passes through butanol pre-distillation column 2 to remove light components and butanol distillation column 8 to remove light components, heavy components and impurities. Then, it passes through two isomerization columns with different pressures to separate n-butanol and isobutanol, obtaining n-butanol and isobutanol products. The pressure settings of the two columns, butanol isomerization column one and butanol isomerization column two, meet the requirements of balancing energy consumption and separation effect.

[0042] In the octanol separation process, a mixture of n-butyraldehyde and isobutyraldehyde is separated by two isomerization towers with different pressures. The n-butyraldehyde is then hydrogenated to obtain crude octanol. The crude octanol is then passed through octanol pre-distillation tower 38 and octanol distillation tower 44 to remove light components, heavy components, and impurities, yielding the octanol product. The butyraldehyde isomerization tower 1 and the butyraldehyde isomerization tower 2 have different pressures, with the higher-pressure tower having a higher temperature and a higher top temperature than the lower-pressure tower, resulting in a temperature difference.

[0043] The overhead vapor phase of the butanol distillation column serves as a heat source for the butanol isomer II column, and the overhead vapor phase of the butanol isomer II column serves as a heat source for the butanol isomer I column; the overhead vapor phase of the octanol distillation column serves as a partial heat source for the reboiler of the butyraldehyde isomer II column, and the overhead vapor phase of the butyraldehyde isomer II column serves as a heat source for the reboiler of the butyraldehyde isomer I column.

[0044] The top temperature of the butanol distillation column is greater than the bottom temperature of the butanol isomer II column, and the top temperature of the butanol isomer II column is greater than the bottom temperature of the butanol isomer I column.

[0045] The top temperature of the octanol distillation column is greater than the bottom temperature of the butyraldehyde isomer II column, and the top temperature of the butyraldehyde isomer II column is greater than the bottom temperature of the butyraldehyde isomer I column.

[0046] Furthermore, the temperature difference between any two must be no less than 5℃.

[0047] The temperature difference between the two pairs is 5℃ to 50℃, preferably 10℃ to 30℃.

[0048] The butanol pre-distillation column 2 has a top pressure of atmospheric pressure to 100 kPa(G), a top temperature of 70 to 140°C, and a bottom temperature of 100 to 170°C.

[0049] The top pressure of the butanol distillation column 8 is atmospheric pressure ~100 kPa(G), the top temperature is 90~170℃, and the bottom temperature is 110~190℃.

[0050] The pressure at the top of column 14 for butanol isomers is -100 kPa(G) to atmospheric pressure, and the temperature at the top of column is 20 to 100 °C, while the temperature at the bottom of column is 40 to 120 °C.

[0051] The pressure at the top of the butanol isomer two-column 20 is -60kPa(G) to 40kPa(G), the temperature at the top of the column is 60 to 140℃, and the temperature at the bottom of the column is 80 to 160℃.

[0052] The pressure at the top of the butyraldehyde isomer tower 25 is -100kPa(G) to atmospheric pressure, the temperature at the top of the tower is 20 to 100℃, and the temperature at the bottom of the tower is 40 to 120℃.

[0053] The pressure at the top of the butyraldehyde isomer two-column 31 is atmospheric pressure ~200kPa(G), the temperature at the top of the column is 40~140℃, and the temperature at the bottom of the column is 60~160℃.

[0054] The pressure at the top of the octanol pre-distillation column 38 is -100 kPa(G) to atmospheric pressure, the temperature at the top is 60 to 140°C, and the temperature at the bottom is 100 to 180°C.

[0055] The pressure at the top of the octanol distillation column 44 is -100 kPa(G) to atmospheric pressure, the temperature at the top is 90 to 160°C, and the temperature at the bottom is 110 to 190°C.

[0056] Each tower is either a plate tower or a packed tower, and the flow parameter FP value of each tower is between 0.02 and 0.2. When it is a packed tower, the internal components of the tower include packing, packing support rings and liquid distributors.

[0057] The raw material can be a mixture of butyraldehyde, a product of propylene carbonylation reaction, or a mixture with n-butyraldehyde and isobutyraldehyde as the main components; the mass percentage composition range of the raw material is: 90% to 100% of the mixture of n-butyraldehyde and isobutyraldehyde, 0% to 4% of the light components, and 0% to 6% of the heavy components; the ratio of n-butanol to isobutanol is between 1:1 and 15:1.

[0058] Compared with the prior art, the beneficial effects of the present invention are:

[0059] 1. In this invention, the butanol separation process is separated from the octanol separation process, allowing for a certain degree of flexibility in adjusting the reaction ratio of butanol and octanol, thus enabling more flexible adaptation to market demands. Both the butanol and octanol separation processes employ triple-effect energy-saving heat exchange designs, significantly reducing energy consumption. This overcomes the problem in conventional butanol-octanol separation processes where conventional heat sources and refrigerants are used directly for heating or cooling in the distillation column, resulting in ineffective utilization of the waste heat from the top gas phase.

[0060] 2. In this invention, the top vapor phase of the butanol distillation column is used as a heat source for the reboiler of the butanol isomer secondary column, and the top vapor phase of the octanol distillation column is used as a heat source for the reboiler of the butyraldehyde isomer secondary column. The heat of these two high-temperature streams is fully utilized, so that the butanol isomer secondary column no longer needs an additional heat source, thus reducing the energy consumption in the entire process.

[0061] 3. In this invention, the butanol isomerization tower and butyraldehyde isomerization tower are changed from a single-tower process in the Davy process to a dual-tower thermal coupling process. Different thermal coupling heat exchange flows are designed, splitting one tower into two. The two towers have the same function but different operating conditions: the higher-pressure tower has a higher temperature, and the lower-pressure tower has a lower temperature. This ensures that the top temperature of the high-pressure tower is higher than the bottom temperature of the low-pressure tower, creating a temperature difference that allows for double-effect heat exchange between the two towers. The tower pressures of both the butanol isomerization tower and the butyraldehyde isomerization tower are changed from slightly positive pressure in the Davy process to reduced pressure, lowering the overall operating temperature of the towers. The top gas phase of the butanol isomerization tower and the butyraldehyde isomerization tower use the reboiler of the butyraldehyde isomerization tower as heat sources, eliminating the need for additional heat sources for the butanol and butyraldehyde isomerization towers and reducing energy consumption in the entire process. This avoids the problems in the existing Davy process where the butanol isomer tower and butyraldehyde isomer tower use micro-positive pressure (the top pressure of the butanol isomer tower in the Davy process is around 20-40 kPa(G), and the top pressure of the butyraldehyde isomer tower in the Davy process is around 40-60 kPa(G), which causes the temperature of the entire tower to be too high. At the same time, in order to separate the positive and negative isomers, the entire tower is not only very tall, but also consumes a lot of energy.

[0062] 4. In the Davy process, the operating conditions of each column were not intentionally controlled to create a temperature difference, resulting in a high temperature at the bottom and a low temperature at the top. This invention redesigns each column for different processes, considering its specific design purpose and operating conditions, exploring more energy-efficient operating conditions while still achieving the desired separation effect. By controlling the column pressure, a sequential temperature difference is created between the columns (top temperature of the butanol distillation column > bottom temperature of the butanol isomer II column, top temperature of the butanol isomer II column > bottom temperature of the butanol isomer I column).

[0063] The top temperature of the octanol distillation column is greater than the bottom temperature of the butyraldehyde isomer II column, and the top temperature of the butyraldehyde isomer II column is greater than the bottom temperature of the butyraldehyde isomer I column.

[0064] Furthermore, the temperature difference between each pair must be no less than 5℃, thus enabling the construction of a heat exchange network based on different temperature differences, laying the foundation for the energy-saving optimization design of the entire system.

[0065] 5. In this embodiment of the invention, the internal components and operating conditions of each tower have been rearranged. In the Davy process, due to limitations of time and technology, the towers all use plate tower structures, and the internal components use trays, resulting in a large overall pressure drop and a high bottom temperature. This invention replaces the trays of the Davy process with packing material in the internal components, significantly reducing the overall pressure drop and further lowering the bottom temperature, providing a foundation for the subsequent design of triple-effect heat exchangers. This invention can achieve triple-effect heat exchange with low energy consumption, a reasonable design, and simple operation. Compared to other industrial energy-saving designs, this method requires less investment, is practical and reliable, and has significant effects. Compared to the Davy process, this invention can save approximately 40-60% of energy. Attached Figure Description

[0066] Figure 1 This is a process flow diagram of the triple-effect distillation method for producing butanol and octanol according to the present invention.

[0067] In the diagram, 1 is the butanol reaction system; 2 is the butanol pre-distillation column; 3 is the butanol pre-distillation column reboiler; 4 is the butanol pre-distillation column condenser; 5 is the butanol pre-distillation column reflux phase separator; 6 is the butanol pre-distillation column reflux pump; 7 is the butanol pre-distillation column bottom pump; 8 is the butanol distillation column; 9 is the butanol distillation column reboiler; 10 is the butanol distillation column reflux phase separator; 11 is the butanol distillation column reflux pump; 12 is the butanol distillation column bottom pump; and 13 is the butanol distillation column side-stream pump. 14. Butanol isomer first tower; 15. Butanol isomer first tower reboiler; 16. Butanol isomer first tower condenser; 17. Butanol isomer first tower reflux tank; 18. Butanol isomer first tower reflux pump; 19. Butanol isomer first tower bottom pump; 20. Butanol isomer second tower; 21. Butanol isomer second tower reboiler; 22. Butanol isomer second tower reflux tank; 23. Butanol isomer second tower reflux pump; 24. Butanol isomer second tower bottom pump; 25. Butanal isomer 26. Butyraldehyde isomer tower 1; 27. Butyraldehyde isomer tower 1 reboiler; 28. Butyraldehyde isomer tower 1 reflux phase separator; 29. ​​Butyraldehyde isomer tower 1 reflux pump; 30. Butyraldehyde isomer tower 1 bottom pump; 31. Butyraldehyde isomer tower 2; 32. Butyraldehyde isomer tower 2 No. 1 reboiler; 33. Butyraldehyde isomer tower 2 No. 2 reboiler; 34. Butyraldehyde isomer tower 2 reflux phase separator; 35. Butyraldehyde isomer tower 2 reflux pump; 36. Butyraldehyde isomer tower 2 Aldehyde isomer two-column bottom pump; 37-Octanol reaction system; 38-Octanol pre-distillation column; 39-Octanol pre-distillation column reboiler; 40-Octanol pre-distillation column condenser; 41-Octanol pre-distillation column reflux separation tank; 42-Octanol pre-distillation column reflux pump; 43-Octanol pre-distillation column bottom pump; 44-Octanol distillation column; 45-Octanol distillation column reboiler; 46-Octanol distillation column reflux tank; 47-Octanol distillation column reflux pump; 48-Octanol distillation column bottom pump. Detailed Implementation

[0068] The present invention will be further explained below with reference to the embodiments and accompanying drawings, but this is not intended to limit the scope of protection of this application.

[0069] This invention discloses a butanol and octanol production equipment, comprising a butanol pre-distillation column 2, a butanol distillation column 8, a butanol isomer first column 14, a butanol isomer second column 20, a butanol isomer first column 25, a butanol isomer second column 31, an octanol pre-distillation column 38, and an octanol distillation column 44, totaling 8 columns, each equipped with a corresponding condenser, reflux phase separator, and reboiler;

[0070] The feed inlet of the butanol pre-distillation column 2 is connected to the outlet of the butanol reaction system 1, wherein the feed of the butanol reaction system is mixed butyraldehyde from the propylene carbonylation reaction;

[0071] The bottom feed of the butanol pre-distillation column 2 is connected to the feed of the butanol distillation column 8, and the top of the butanol pre-distillation column 2 is refluxed and collected as a light component.

[0072] The heavy component is collected from the bottom of the butanol distillation column 8, and the vapor phase at the top of the column is connected to the heat exchange inlet of the reboiler at the bottom of the butanol isomer secondary column 20. The heat exchange outlet of the reboiler at the bottom of the butanol isomer secondary column 20 is connected to the reflux phase separator set at the top of the butanol distillation column 8 for reflux. At the same time, the reflux material at the top of the butanol distillation column 8 is connected to the feed inlet of the butanol pre-distillation column 2 through a pipeline.

[0073] The side outlets of the butanol distillation column 8 are connected to the butanol isomer first column 14 and the butanol isomer second column 20, respectively.

[0074] The reboiler of the butanol isomer tower 14 is connected to the top of the butanol isomer tower 20 for heat exchange, and n-butanol is extracted from both the bottom of the butanol isomer tower 14 and the bottom of the butanol isomer tower 20.

[0075] A portion of the material refluxed from the top of the butanol isomer tower 14 is connected to the top inlet of the butanol isomer tower 14 via a pipeline, while the other portion is collected as isobutanol.

[0076] A portion of the material refluxed from the top of the butanol isomer secondary column 20 is connected to the top inlet of the butanol isomer secondary column via a pipeline, while the other portion is collected as isobutanol.

[0077] The feed for both the butyraldehyde isomer tower 25 and the butyraldehyde isomer tower 31 is a mixture of butyraldehyde from the propylene carbonylation reaction. The reflux effluent from the top of the butyraldehyde isomer tower 25 and the butyraldehyde isomer tower 31 is mainly isobutyraldehyde or mixed butyraldehyde. The reflux effluent from the top of the butyraldehyde isomer tower 25 and the butyraldehyde isomer tower 31 can be connected to the feed inlet of the butanol reaction system 1.

[0078] The reboiler of the butyraldehyde isomer first tower 25 exchanges heat with the top of the butyraldehyde isomer second tower 31, and the bottom of the butyraldehyde isomer first tower 25 and the bottom of the butyraldehyde isomer second tower 31 are connected to the inlet of the octanol pre-distillation tower 38 after passing through the octanol reaction system 37.

[0079] The bottom reboiler of the butyraldehyde isomer secondary column 31 exchanges heat with the top of the octanol distillation column;

[0080] A portion of the material refluxed from the top of the octanol pre-distillation column 38 is connected to the top inlet of the octanol pre-distillation column 38 via a pipeline, while the other portion is collected as a light component.

[0081] The bottom outlet of the octanol pre-distillation column 38 is connected to the inlet of the octanol distillation column 44; the bottom of the octanol distillation column collects heavy components, and the top of the column is condensed and refluxed to collect octanol.

[0082] Furthermore, the butyraldehyde isomer secondary tower 31 is equipped with two reboilers connected in parallel: one is the first reboiler 32 of the butyraldehyde isomer secondary tower, which uses steam as the heat source; the other is the second reboiler 33 of the butyraldehyde isomer secondary tower, which uses the vapor phase at the top of the octanol distillation tower as the heat source.

[0083] This invention also protects a butanol separation device, including a butanol pre-distillation column 2, a butanol distillation column 8, a butanol isomer first column 14, and a butanol isomer second column 20, each column being equipped with a corresponding condenser, reflux phase separator and reboiler.

[0084] The feed inlet of the butanol pre-distillation column 2 is connected to the output of the butanol reaction system 1. The main component of the output is mixed butanol (n-butanol and isobutanol). The feed of the butanol reaction system is mixed butyraldehyde from the propylene carbonylation reaction.

[0085] The bottom feed of the butanol pre-distillation column 2 is connected to the feed of the butanol distillation column 8, and the top of the butanol pre-distillation column 2 is refluxed and collected as a light component.

[0086] The heavy component is collected from the bottom of the butanol distillation column 8, and the vapor phase at the top of the column is connected to the heat exchange inlet of the reboiler at the bottom of the butanol isomer secondary column 20. The heat exchange outlet of the reboiler at the bottom of the butanol isomer secondary column 20 is connected to the reflux phase separator set at the top of the butanol distillation column 8 for reflux. At the same time, the reflux material at the top of the butanol distillation column 8 is connected to the feed inlet of the butanol pre-distillation column 2 through a pipeline.

[0087] The side outlet of the butanol distillation column 8 is connected to the butanol isomer first column 14 and the butanol isomer second column 20, respectively.

[0088] The reboiler of the butanol isomer tower 14 is connected to the top of the butanol isomer tower 20 for heat exchange, and n-butanol is extracted from both the bottom of the butanol isomer tower 14 and the bottom of the butanol isomer tower 20.

[0089] A portion of the material refluxed from the top of the butanol isomer tower 14 is connected to the top inlet of the butanol isomer tower 14 via a pipeline, while the other portion is collected as isobutanol.

[0090] A portion of the material refluxed from the top of the butanol isomer secondary column 20 is connected to the top inlet of the butanol isomer secondary column via a pipeline, while the other portion is extracted as isobutanol.

[0091] This invention also protects an octanol separation device, comprising a butyraldehyde isomer first column 25, a butyraldehyde isomer second column 31, an octanol pre-distillation column 38, and an octanol distillation column 44, each column being equipped with a corresponding condenser, reflux phase separator, and reboiler.

[0092] The feed for both the butyraldehyde isomer tower 25 and the butyraldehyde isomer tower 31 is a mixture of butyraldehyde from the propylene carbonylation reaction, and the reflux effluent from the top of the towers is isobutyraldehyde or a mixture of butyraldehyde.

[0093] The reboiler of the butyraldehyde isomer first tower 25 exchanges heat with the top of the butyraldehyde isomer second tower 31, and the bottom of the butyraldehyde isomer first tower 25 and the bottom of the butyraldehyde isomer second tower 31 are connected to the inlet of the octanol pre-distillation tower 38 after passing through the octanol reaction system 37.

[0094] The bottom reboiler of the butyraldehyde isomer secondary column 31 exchanges heat with the top of the octanol distillation column;

[0095] A portion of the material refluxed from the top of the octanol pre-distillation column 38 is connected to the top inlet of the octanol pre-distillation column 38 via a pipeline, while the other portion is collected as a light component.

[0096] The bottom outlet of the octanol pre-distillation column 38 is connected to the inlet of the octanol distillation column 44; the bottom of the octanol distillation column collects heavy components, and the top of the column is condensed and refluxed to collect octanol.

[0097] This invention relates to a triple-effect distillation method for the production of butanol and octanol, comprising two processes: butanol separation and octanol separation. Both processes use the same raw materials and, through different steps, yield n-butanol, isobutanol, and octanol products, respectively. The butanol separation is divided into three parts in sequence: hydrogenation, removal of light and heavy components, and separation of n-isomers. The octanol separation can be divided into three parts in sequence: separation of n-isomers, hydrogenation, and removal of light and heavy components.

[0098] The butanol de-light and de-heavy fraction is completed by butanol pre-distillation column 2 and butanol distillation column 8; the butanol isomerization separation fraction is completed by butanol isomer first column 14 and butanol isomer second column 20; the octanol isomerization separation fraction is completed by butyraldehyde isomer first column 25 and butyraldehyde isomer second column 31; the octanol de-light and de-heavy fraction is completed by octanol pre-distillation column 38 and octanol distillation column 44.

[0099] Propylene feedstock undergoes a carbonylation reaction to obtain a mixture of n- and isobutyraldehyde, which then enters a subsequent butanol separation process or octanol separation process.

[0100] In the butanol separation process, the mixture of n- and isobutyraldehyde is hydrogenated to obtain a mixture of n- and isobutanol, i.e., crude butanol. The crude butanol first passes through butanol pre-distillation column 2 to remove light components and butanol distillation column 8 to remove light components, heavy components, water, and other impurities. Then, it passes through two isomerization columns with different pressures (the pressure settings of the first butanol isomerization column and the second butanol isomerization column meet the requirements of balancing energy consumption and separation effect) to separate n-butanol and isobutanol, obtaining n-butanol and isobutanol products.

[0101] In the octanol separation process, a mixture of n-butyraldehyde and isobutyraldehyde is separated from n-butyraldehyde by passing through two isomerization towers with different pressures (butyraldehyde isomerization tower one and butyraldehyde isomerization tower two; one tower has a high pressure and the other a low pressure. The tower with the high pressure has a high temperature, and the temperature at the top of the tower is higher than the temperature at the bottom of the tower with the low pressure. A certain temperature difference is required for heat exchange). The n-butyraldehyde is then hydrogenated to obtain crude octanol. Finally, the crude octanol is passed through octanol pre-distillation tower 38 and octanol distillation tower 44 to remove light components, heavy components, and impurities, yielding the octanol product.

[0102] The overhead vapor phase of the butanol distillation column serves as a heat source for the butanol isomer II column, while the overhead vapor phase of the butanol isomer II column serves as a heat source for the butanol isomer I column. Similarly, the overhead vapor phase of the octanol distillation column serves as a partial heat source for the reboiler of the butyraldehyde isomer II column, while the overhead vapor phase of the butyraldehyde isomer II column serves as a heat source for the reboiler of the butyraldehyde isomer I column. In the butanol and octanol separation processes, each column forms a triple-effect heat exchange network, significantly reducing energy consumption. The triple-effect heat exchange network refers to a system where three columns participate in heat exchange in each process.

[0103] The specific process of triple-effect distillation for the production of butanol and octanol is as follows:

[0104] In the butanol separation process:

[0105] The mixed butyraldehyde from the propylene carbonylation reaction is hydrogenated in butanol reaction system 1 to obtain mixed butanol containing a small amount of impurities.

[0106] The mixed butanol is sent to the butanol pre-distillation column 2. The butanol pre-distillation column 2 is equipped with a reboiler 3, which uses steam as the heat source for the reboiler. The top pressure of the butanol pre-distillation column 2 is atmospheric pressure ~100 kPa (G), where G represents gauge pressure. The top temperature is 70 ~140℃, and the bottom temperature is 100 ~170℃. The vapor phase at the top of the butanol pre-distillation column 2 enters the butanol pre-distillation column condenser 4 for condensation, using circulating water as the condenser coolant. The condensed liquid enters the butanol pre-distillation column reflux phase separator 5. The aqueous phase in the reflux phase separator 5 is discharged from the boundary area. The organic phase in the reflux phase separator 5 is transported by the butanol pre-distillation column reflux pump 6. Part of it is returned to the top of the butanol pre-distillation column 2 as reflux, and the other part is collected as a light component.

[0107] The material at the bottom of the butanol pre-distillation column 2 is pumped into the butanol distillation column 8 via the butanol pre-distillation column bottom pump 7. The butanol distillation column 8 is equipped with a reboiler 9, using steam as the heat source. The top pressure of the butanol distillation column 8 is atmospheric pressure to 100 kPa(G), the top temperature is 90–170℃, and the bottom temperature is 110–190℃. The vapor phase at the top of the butanol distillation column 8 enters the butanol isomer reboiler 21 for condensation. The condensed liquid enters the butanol distillation column reflux phase separator 10. The aqueous phase in the reflux phase separator 10 is discharged from the boundary area, and the organic phase in the reflux phase separator 10 is pumped by the butanol distillation column reflux pump 11. Part of it is returned to the top of the butanol distillation column 8 as reflux, and the other part is collected as a light component and returned to the butanol pre-distillation column 2. The heavy components at the bottom of the butanol distillation column 8 are collected by the butanol distillation column bottom pump 12. The material collected from the side stream of the butanol distillation column 8 is divided into two streams after being collected by the butanol distillation column side stream pump 13. One stream enters the butanol isomer first column 14, and the other stream enters the butanol isomer second column 20.

[0108] The butanol isomer first column 14 is equipped with a reboiler 15, using the overhead vapor from the butanol isomer second column as the heat source for the reboiler. The overhead pressure of the butanol isomer first column 14 is between -100 kPa(G) and atmospheric pressure, the overhead temperature is 20–100℃, and the bottom temperature is 40–120℃. The overhead vapor from the butanol isomer first column 14 enters the butanol isomer first column condenser 16 for condensation, using circulating water as the condenser coolant. The condensed liquid enters the butanol isomer first column reflux tank 17. The material in the reflux tank 17 is conveyed by the butanol isomer first column reflux pump 18, with part of it returning to the top of the butanol isomer first column 14 as reflux and part being collected as isobutanol product. The n-butanol product at the bottom of the butanol isomer first column 14 is transported to the n-butanol product tank by the butanol isomer first column bottom pump 19.

[0109] The butanol isomer secondary column 20 is equipped with a reboiler 21, using the overhead vapor from the butanol distillation column as the heat source. The overhead pressure of the butanol isomer secondary column 20 is -60 kPa(G) to 40 kPa(G), the overhead temperature is 60 to 140℃, and the bottom temperature is 80 to 160℃. The overhead vapor from the butanol isomer secondary column 20 enters the reboiler 15 of the butanol isomer primary column for condensation. The condensed liquid enters the reflux tank 22 of the butanol isomer secondary column. The material in the reflux tank 22 is transported by the reflux pump 23, with part of it returning to the top of the butanol isomer secondary column 20 as reflux and part being collected as isobutanol product. The n-butanol product at the bottom of the butanol isomer secondary column 20 is pumped by the bottom pump 24 to the n-butanol product tank.

[0110] In the octanol separation process:

[0111] The mixed butyraldehyde from the propylene carbonylation reaction is divided into two streams, one of which enters the butyraldehyde isomer tower 25 and the other enters the butyraldehyde isomer tower 31.

[0112] A reboiler 26 is installed in the butyraldehyde isomer tower 25, using the top gas phase of the butyraldehyde isomer tower 2 as the heat source for the reboiler. The top pressure of the butyraldehyde isomer tower 25 is between -100 kPa(G) and atmospheric pressure, the top temperature is 20-100℃, and the bottom temperature is 40-120℃. The top gas phase of the butyraldehyde isomer tower 25 enters the butyraldehyde isomer tower condenser 27 for condensation, using circulating water as the condenser coolant. The condensed liquid enters the butyraldehyde isomer tower reflux phase separator 28. The material in the reflux phase separator 28 is transported by the butyraldehyde isomer tower reflux pump 29. Part of it is returned to the top of the butyraldehyde isomer tower 25 as reflux, and part of it is collected as isobutyraldehyde or mixed butyraldehyde products. The collected isobutyraldehyde or mixed butyraldehyde products can enter the butanol separation process to participate in subsequent reactions. The material at the bottom of the butyraldehyde isomer tower 25 is transported by the butyraldehyde isomer tower bottom pump 30 to extract n-butyraldehyde.

[0113] The butyraldehyde isomer secondary column 31 is equipped with two reboilers: one is reboiler 32, which uses steam as its heat source; the other is reboiler 33, which uses the vapor phase from the top of the octanol distillation column 44 as its heat source. The pressure at the top of the butyraldehyde isomer secondary column 31 is atmospheric pressure to 200 kPa(G), the temperature at the top is 40–140℃, and the temperature at the bottom is 60–160℃. The vapor phase from the top of the butyraldehyde isomer secondary column 31 enters the reboiler 26 of the butyraldehyde isomer secondary column for condensation. The condensed liquid enters the reflux phase separator 34 of the butyraldehyde isomer secondary column. The aqueous phase in the reflux phase separator 34 is discharged from the boundary area, and the organic phase in the reflux phase separator 34 is transported by the butyraldehyde isomer secondary column reflux pump 35. Part of it is returned to the top of the butyraldehyde isomer secondary column 31 as reflux, and the other part is collected and sent to the isobutyraldehyde or mixed butyraldehyde storage tank. The material at the bottom of the butyraldehyde isomer secondary tower 31 is transported by the butyraldehyde isomer secondary tower bottom pump 36 to extract n-butyraldehyde.

[0114] n-Butyraldehyde is condensed and hydrogenated in octanol reaction system 37 to obtain crude octanol containing a small amount of impurities.

[0115] The material from the octanol reaction system is sent to the octanol pre-distillation column 38. The octanol pre-distillation column 38 is equipped with a reboiler 39, which uses steam as the heat source for the reboiler. The top pressure of the octanol pre-distillation column 38 is -100 kPa(G) to atmospheric pressure, the top temperature is 60 to 140°C, and the bottom temperature is 100 to 180°C. The vapor phase at the top of the octanol pre-distillation column 38 enters the octanol pre-distillation column condenser 40 for condensation. The condensed liquid enters the octanol pre-distillation column reflux phase separator 41. The aqueous phase in the reflux phase separator 41 is discharged from the boundary area. The organic phase in the reflux phase separator 41 is transported by the octanol pre-distillation column reflux pump 42. Part of it is returned to the top of the octanol pre-distillation column 38 as reflux, and part of it is collected as a light component.

[0116] The bottom product of the octanol pre-distillation column 38 is transported to the octanol distillation column 44 via the octanol pre-distillation column bottom pump 43. The octanol distillation column 44 is equipped with a reboiler 45, using steam as the heat source. The top pressure of the octanol distillation column 44 is -100 kPa(G) to atmospheric pressure, the top temperature is 90–160℃, and the bottom temperature is 110–190℃. The vapor phase from the top of the octanol distillation column 44 enters the butyraldehyde isomer reboiler 33 for condensation. The condensed liquid enters the octanol distillation column reflux tank 46. The material in the reflux tank 46 is transported by the octanol distillation column reflux pump 47, with a portion returning to the top of the octanol distillation column 44 as reflux and a portion being collected as octanol product. The bottom product of the octanol distillation column 44, as a heavy component, is collected via the octanol distillation column bottom pump 48.

[0117] Furthermore, the top temperature of the butanol distillation column is greater than the bottom temperature of the butanol isomer II column, and the top temperature of the butanol isomer II column is greater than the bottom temperature of the butanol isomer I column.

[0118] The top temperature of the octanol distillation column is greater than the bottom temperature of the butyraldehyde isomer II column, and the top temperature of the butyraldehyde isomer II column is greater than the bottom temperature of the butyraldehyde isomer I column.

[0119] Furthermore, the temperature difference between any two elements is required to be no less than 5°C, with the temperature difference between any two elements being 5°C to 50°C, preferably 10°C to 30°C.

[0120] Temperature difference is the driving force for heat transfer in a heat exchanger, according to the basic heat transfer equation:

[0121] Q=KAΔtm

[0122] Where Q is the heat transfer rate, W

[0123] K – proportionality coefficient, W / m²·℃

[0124] A – Heat exchange area, m 2

[0125] Δtm — driving force for heat transfer, °C

[0126] The driving force for heat transfer comes from the temperature difference between the hot and cold streams. If the temperature difference is too small, it is easy to cause temperature cross-contamination, which will affect heat exchange. In addition, the heat exchanger area will be very large, which is not economically reasonable. In order to create a temperature difference between different towers, pressure needs to be controlled. If the pressure difference between the two towers is increased simply to expand the temperature difference between them, it is also not economically reasonable. Therefore, the temperature difference between the top and bottom of the two towers that need to exchange heat is limited to the range of 5 to 50°C.

[0127] In this invention, the raw materials can be a mixture of butyraldehyde, a product of the propylene carbonylation reaction, or a mixture with n-butyraldehyde and isobutyraldehyde as the main components. Preferably, the raw material composition range that meets the process requirements is: 90%–100% of the mixture of n-butyraldehyde and isobutyraldehyde, 0%–4% of the light components, and 0%–6% of the heavy components; the ratio of n-butanol to isobutanol can be between 1:1 and 15:1.

[0128] In this invention, the top reflux effluent from the butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 is isobutyraldehyde or mixed butyraldehyde can be collected for other uses, preferably it can be entered into the butanol reaction system as a raw material to participate in the reaction again.

[0129] The internal components of each column are selected based on the different physical properties of the gas and liquid phases, and can be chosen according to the following formula:

[0130] Flow parameters

[0131] Where L represents the liquid load, in kmol / s.

[0132] V — Gas load, kmol / s

[0133] ρ g —Gas density, kg / m³ 3

[0134] ρ l —Liquid density, kg / m³ 3

[0135] When FP = 0.02 to 0.3, packed towers have higher efficiency than plate towers. In the process of this invention, the FP values ​​of each tower are between 0.02 and 0.2, making packed towers more suitable. In addition, packed towers have better separation effect at the same tower height and lower overall tower pressure drop, making them easier to meet the requirements of the heat exchange system in this invention. Therefore, packed towers are selected in all the following embodiments.

[0136] Example 1:

[0137] In the butanol separation process:

[0138] Mixed butyraldehyde (in a ratio of approximately 10:1 to n-butyraldehyde) from the propylene carbonylation reaction is hydrogenated in butanol reaction system 1 to obtain mixed butanol containing a small amount of impurities.

[0139] The mixed butanol is sent to the butanol pre-distillation column 2, which is equipped with a reboiler 3, using steam as the heat source. The top pressure of the butanol pre-distillation column 2 is 50 kPa(G), the top temperature is 99℃, and the bottom temperature is 133℃. The vapor phase at the top of the butanol pre-distillation column 2 enters the butanol pre-distillation column condenser 4 for condensation, using circulating water as the condenser coolant. The condensed liquid enters the butanol pre-distillation column reflux phase separator 5. The aqueous phase in the butanol pre-distillation column reflux phase separator 5 is discharged from the boundary area. The organic phase in the butanol pre-distillation column reflux phase separator 5 is transported by the butanol pre-distillation column reflux pump 6. Part of it is returned to the top of the butanol pre-distillation column 2 as reflux, and the other part is collected as a light component.

[0140] The material at the bottom of the butanol pre-distillation column 2 is pumped into the butanol distillation column 8 via the bottom pump 7. The butanol distillation column 8 is equipped with a butanol reboiler 9, using steam as its heat source. The top pressure of the butanol distillation column 8 is 50 kPa(G), the top temperature is 137℃, and the bottom temperature is 168℃. The vapor phase from the top of the butanol distillation column 8 enters the butanol isomer reboiler 21 for condensation. The condensed liquid enters the butanol distillation column reflux phase separator 10. The aqueous phase in the reflux phase separator 10 is discharged from the boundary area. The organic phase in the reflux phase separator 10 is pumped by the butanol distillation column reflux pump 11; part of it is returned to the top of the butanol distillation column 8 as reflux, and the other part is collected as a light component and returned to the butanol pre-distillation column 2. The heavy components at the bottom of the butanol distillation column 8 are collected by the bottom pump 12. The material collected from the side stream of the butanol distillation column 8 is divided into two streams after being collected by the butanol distillation column side stream pump 13. One stream enters the butanol isomer first column 14, and the other stream enters the butanol isomer second column 20.

[0141] The butanol isomer first column 14 is equipped with a butanol isomer first column reboiler 15, using the overhead vapor phase from the butanol isomer second column as the heat source for the butanol isomer first column reboiler; the overhead pressure of the butanol isomer first column 14 is -60 kPa(G), the overhead temperature is 76℃, and the bottom temperature is 90℃; the overhead vapor phase from the butanol isomer first column 14 enters the butanol isomer first column condenser 16 for condensation, using circulating water as the condenser coolant; the condensed liquid enters the butanol isomer first column reflux tank 17; the material in the butanol isomer first column reflux tank 17 is conveyed by the butanol isomer first column reflux pump 18, with part returning as reflux to the top of the butanol isomer first column 14, and part being collected as isobutanol product. The n-butanol product at the bottom of the butanol isomer first column 14 is transported to the n-butanol product tank by the butanol isomer first column bottom pump 19.

[0142] The butanol isomer secondary column 20 is equipped with a butanol isomer secondary column reboiler 21, using the overhead vapor phase of the butanol distillation column as the heat source for the reboiler. The overhead pressure of the butanol isomer secondary column 20 is -15 kPa(G), the overhead temperature is 110℃, and the bottom temperature is 125℃. The overhead vapor phase of the butanol isomer secondary column 20 enters the butanol isomer primary column reboiler 15 for condensation. The condensed liquid enters the butanol isomer secondary column reflux tank 22. The material in the butanol isomer secondary column reflux tank 22 is conveyed by the butanol isomer secondary column reflux pump 23, with part of it returning to the top of the butanol isomer secondary column 20 as reflux and part of it being collected as isobutanol product. The n-butanol product at the bottom of the butanol isomer secondary column 20 is transported to the n-butanol product tank by the butanol isomer secondary column bottom pump 24.

[0143] In the octanol separation process:

[0144] The mixed butyraldehyde from the propylene carbonylation reaction (in which the ratio of n-butyraldehyde to isobutyraldehyde is approximately 10:1) is divided into two streams, one of which enters the butyraldehyde isomer tower 25 and the other enters the butyraldehyde isomer tower 31.

[0145] The butyraldehyde isomer first tower 25 is equipped with a butyraldehyde isomer first tower reboiler 26, using the top gas phase of the butyraldehyde isomer second tower as the heat source for the butyraldehyde isomer first tower reboiler; the top pressure of the butyraldehyde isomer first tower 25 is -50 kPa(G), the top temperature is 55℃, and the bottom temperature is 70℃; the top gas phase of the butyraldehyde isomer first tower 25 enters the butyraldehyde isomer first tower condenser 27 for condensation, using circulating water as the condenser refrigerant; the condensed liquid enters the butyraldehyde isomer first tower reflux phase separator 28; the material in the butyraldehyde isomer first tower reflux phase separator 28 is conveyed by the butyraldehyde isomer first tower reflux pump 29, with part returning as reflux to the top of the butyraldehyde isomer first tower 25, and part being collected as isobutanol or mixed butanol products. The material at the bottom of the butyraldehyde isomer first tower 25 is conveyed by the butyraldehyde isomer first tower bottom pump 30 to collect n-butyraldehyde.

[0146] The butyraldehyde isomer secondary column 31 is equipped with two reboilers: one is reboiler 32, which uses steam as its heat source; the other is reboiler 33, which uses the vapor from the top of the octanol distillation column as its heat source. The pressure at the top of the butyraldehyde isomer secondary column 31 is 100 kPa(G), the temperature at the top is 80℃, and the temperature at the bottom is 98℃. The vapor from the top of the butyraldehyde isomer secondary column 31 enters the reboiler 26 of the butyraldehyde isomer secondary column for condensation. The condensed liquid enters the reflux phase separator 34 of the butyraldehyde isomer secondary column. The aqueous phase in the reflux phase separator 34 is discharged from the boundary area. The organic phase in the reflux phase separator 34 is transported by the reflux pump 35 of the butyraldehyde isomer secondary column. Part of it is returned to the top of the butyraldehyde isomer secondary column 31 as reflux, and the other part is collected and sent to the isobutyraldehyde or mixed butyraldehyde storage tank. The material at the bottom of the butyraldehyde isomer secondary tower 31 is transported by the butyraldehyde isomer secondary tower bottom pump 36 to extract n-butyraldehyde.

[0147] n-Butyraldehyde is condensed and hydrogenated in octanol reaction system 37 to obtain crude octanol containing a small amount of impurities.

[0148] The material from the octanol reaction system is sent to the octanol pre-distillation column 38. The octanol pre-distillation column 38 is equipped with an octanol pre-distillation column reboiler 39, which uses steam as the heat source. The top pressure of the octanol pre-distillation column 38 is -50 kPa(G), the top temperature is 80℃, and the bottom temperature is 146℃. The vapor phase at the top of the octanol pre-distillation column 38 enters the octanol pre-distillation column condenser 40 for condensation. The condensed liquid enters the octanol pre-distillation column reflux phase separator 41. The aqueous phase in the octanol pre-distillation column reflux phase separator 41 is discharged from the boundary area. The organic phase in the octanol pre-distillation column reflux phase separator 41 is transported by the octanol pre-distillation column reflux pump 42. Part of it is returned to the top of the octanol pre-distillation column 38 as reflux, and part of it is collected as a light component.

[0149] The bottom product of the octanol pre-distillation column 38 is pumped to the octanol distillation column 44 via the octanol pre-distillation column bottom pump 43. The octanol distillation column 44 is equipped with an octanol reboiler 45, using steam as the heat source. The top pressure of the octanol distillation column 44 is -50 kPa(G), the top temperature is 146℃, and the bottom temperature is 170℃. The vapor phase from the top of the octanol distillation column 44 enters the butyraldehyde isomer reboiler 33 for condensation. The condensed liquid enters the octanol distillation column reflux tank 46. The material in the octanol distillation column reflux tank 46 is pumped by the octanol distillation column reflux pump 47, with a portion returning to the top of the octanol distillation column 44 as reflux and a portion being collected as octanol product. The bottom product of the octanol distillation column 44, as a heavy component, is collected via the octanol distillation column bottom pump 48.

[0150] Example 2:

[0151] In the butanol separation process:

[0152] Mixed butyraldehyde (in which the ratio of n-butyraldehyde to isobutyraldehyde is approximately 5:1) is passed through butanol reaction system 1 and hydrogenated as a whole to obtain mixed butanol containing a small amount of impurities.

[0153] The mixed butanol is sent to the butanol pre-distillation column 2, which is equipped with a reboiler 3, using steam as the heat source. The top pressure of the butanol pre-distillation column 2 is 20 kPa(G), the top temperature is 82℃, and the bottom temperature is 113℃. The vapor phase at the top of the butanol pre-distillation column 2 enters the butanol pre-distillation column condenser 4 for condensation, using circulating water as the condenser coolant. The condensed liquid enters the butanol pre-distillation column reflux phase separator 5. The aqueous phase in the butanol pre-distillation column reflux phase separator 5 is discharged from the boundary area. The organic phase in the butanol pre-distillation column reflux phase separator 5 is transported by the butanol pre-distillation column reflux pump 6. Part of it is returned to the top of the butanol pre-distillation column 2 as reflux, and the other part is collected as a light component.

[0154] The material at the bottom of the butanol pre-distillation column 2 is pumped into the butanol distillation column 8 via the bottom pump 7. The butanol distillation column 8 is equipped with a butanol reboiler 9, using steam as its heat source. The top pressure of the butanol distillation column 8 is 20 kPa(G), the top temperature is 114℃, and the bottom temperature is 133℃. The vapor phase from the top of the butanol distillation column 8 enters the butanol isomer reboiler 21 for condensation. The condensed liquid enters the butanol distillation column reflux phase separator 10. The aqueous phase in the reflux phase separator 10 is discharged from the boundary area. The organic phase in the reflux phase separator 10 is pumped by the butanol distillation column reflux pump 11; part of it is returned to the top of the butanol distillation column 8 as reflux, and the other part is collected as a light component and returned to the butanol pre-distillation column 2. The heavy components at the bottom of the butanol distillation column 8 are collected by the bottom pump 12. The material collected from the side stream of the butanol distillation column 8 is divided into two streams after being collected by the butanol distillation column side stream pump 13. One stream enters the butanol isomer first column 14, and the other stream enters the butanol isomer second column 20.

[0155] The butanol isomer first column 14 is equipped with a butanol isomer first column reboiler 15, using the overhead vapor phase from the butanol isomer second column as the heat source for the butanol isomer first column reboiler; the overhead pressure of the butanol isomer first column 14 is -78 kPa(G), the overhead temperature is 45℃, and the bottom temperature is 71℃; the overhead vapor phase from the butanol isomer first column 14 enters the butanol isomer first column condenser 16 for condensation, using circulating water as the condenser coolant; the condensed liquid enters the butanol isomer first column reflux tank 17; the material in the butanol isomer first column reflux tank 17 is conveyed by the butanol isomer first column reflux pump 18, with part returning as reflux to the top of the butanol isomer first column 14, and part being collected as isobutanol product. The n-butanol product at the bottom of the butanol isomer first column 14 is transported to the n-butanol product tank by the butanol isomer first column bottom pump 19.

[0156] The butanol isomer secondary column 20 is equipped with a butanol isomer secondary column reboiler 21, using the overhead vapor phase from the butanol distillation column as the heat source for the reboiler. The overhead pressure of the butanol isomer secondary column 20 is -45 kPa(G), the overhead temperature is 88℃, and the bottom temperature is 102℃. The overhead vapor phase from the butanol isomer secondary column 20 enters the butanol isomer primary column reboiler 15 for condensation. The condensed liquid enters the butanol isomer secondary column reflux tank 22. The material in the butanol isomer secondary column reflux tank 22 is conveyed by the butanol isomer secondary column reflux pump 23, with part of it returning to the top of the butanol isomer secondary column 20 as reflux and part of it being collected as isobutanol product. The n-butanol product at the bottom of the butanol isomer secondary column 20 is pumped out to the n-butanol product tank by the butanol isomer secondary column bottom pump 24.

[0157] In the octanol separation process:

[0158] The mixed butyraldehyde (in which the ratio of n-butyraldehyde to isobutyraldehyde is approximately 5:1) is divided into two streams, one of which enters the butyraldehyde isomer tower 25 and the other enters the butyraldehyde isomer tower 31.

[0159] The butyraldehyde isomer first tower 25 is equipped with a butyraldehyde isomer first tower reboiler 26, using the top gas phase of the butyraldehyde isomer second tower as the heat source for the butyraldehyde isomer first tower reboiler; the top pressure of the butyraldehyde isomer first tower 25 is -98 kPa(G), the top temperature is 21℃, and the bottom temperature is 42℃; the top gas phase of the butyraldehyde isomer first tower 25 enters the butyraldehyde isomer first tower condenser 27 for condensation, using circulating water as the condenser refrigerant; the condensed liquid enters the butyraldehyde isomer first tower reflux phase separator 28; the material in the butyraldehyde isomer first tower reflux phase separator 28 is conveyed by the butyraldehyde isomer first tower reflux pump 29, with part returning to the top of the butyraldehyde isomer first tower 25 as reflux, and part being collected as isobutanol or mixed butanol products. The material at the bottom of the butyraldehyde isomer first tower 25 is conveyed by the butyraldehyde isomer first tower bottom pump 30 to collect n-butyraldehyde.

[0160] The butyraldehyde isomer secondary column 31 is equipped with two reboilers: one is reboiler 32, which uses steam as its heat source; the other is reboiler 33, which uses the vapor from the top of the octanol distillation column as its heat source. The pressure at the top of the butyraldehyde isomer secondary column 31 is 50 kPa(G), the temperature at the top is 61℃, and the temperature at the bottom is 81℃. The vapor from the top of the butyraldehyde isomer secondary column 31 enters the reboiler 26 of the butyraldehyde isomer secondary column for condensation. The condensed liquid enters the reflux phase separator 34 of the butyraldehyde isomer secondary column. The aqueous phase in the reflux phase separator 34 is discharged from the boundary area. The organic phase in the reflux phase separator 34 is transported by the reflux pump 35 of the butyraldehyde isomer secondary column. Part of it is returned to the top of the butyraldehyde isomer secondary column 31 as reflux, and the other part is collected to the isobutyraldehyde or mixed butyraldehyde storage tank. The material at the bottom of the butyraldehyde isomer secondary tower 31 is transported by the butyraldehyde isomer secondary tower bottom pump 36 to extract n-butyraldehyde.

[0161] Butyraldehyde is subjected to octanol reaction system 37, and after overall condensation and hydrogenation, crude octanol containing a small amount of impurities is obtained.

[0162] The material from the octanol reaction system is sent to the octanol pre-distillation column 38. The octanol pre-distillation column 38 is equipped with an octanol pre-distillation column reboiler 39, which uses steam as the heat source. The top pressure of the octanol pre-distillation column 38 is -88 kPa(G), the top temperature is 75°C, and the bottom temperature is 138°C. The vapor phase at the top of the octanol pre-distillation column 38 enters the octanol pre-distillation column condenser 40 for condensation. The condensed liquid enters the octanol pre-distillation column reflux phase separator 41. The aqueous phase in the octanol pre-distillation column reflux phase separator 41 is discharged from the boundary area. The organic phase in the octanol pre-distillation column reflux phase separator 41 is transported by the octanol pre-distillation column reflux pump 42. Part of it is returned to the top of the octanol pre-distillation column 38 as reflux, and part of it is collected as a light component.

[0163] The bottom product of the octanol pre-distillation column 38 is pumped to the octanol distillation column 44 via the octanol pre-distillation column bottom pump 43. The octanol distillation column 44 is equipped with an octanol reboiler 45, using steam as the heat source. The top pressure of the octanol distillation column 44 is -90 kPa(G), the top temperature is 97℃, and the bottom temperature is 153℃. The vapor phase from the top of the octanol distillation column 44 enters the butyraldehyde isomer reboiler 33 for condensation. The condensed liquid enters the octanol distillation column reflux tank 46. The material in the octanol distillation column reflux tank 46 is pumped by the octanol distillation column reflux pump 47, with a portion returning to the top of the octanol distillation column 44 as reflux and a portion being collected as octanol product. The bottom product of the octanol distillation column 44, as a heavy component, is collected via the octanol distillation column bottom pump 48.

[0164] Example 3:

[0165] In the butanol separation process:

[0166] Mixed butyraldehyde (in which the ratio of n-butyraldehyde to isobutyraldehyde is approximately 13:1) is passed through butanol reaction system 1 and hydrogenated as a whole to obtain mixed butanol containing a small amount of impurities.

[0167] The mixed butanol is sent to the butanol pre-distillation column 2, which is equipped with a reboiler 3, using steam as the heat source for the reboiler. The top pressure of the butanol pre-distillation column 2 is 96 kPa(G), the top temperature is 135℃, and the bottom temperature is 166℃. The vapor phase at the top of the butanol pre-distillation column 2 enters the butanol pre-distillation column condenser 4 for condensation, using circulating water as the condenser coolant. The condensed liquid enters the butanol pre-distillation column reflux phase separator 5. The aqueous phase in the butanol pre-distillation column reflux phase separator 5 is discharged from the boundary area. The organic phase in the butanol pre-distillation column reflux phase separator 5 is transported by the butanol pre-distillation column reflux pump 6. Part of it is returned to the top of the butanol pre-distillation column 2 as reflux, and the other part is collected as a light component.

[0168] The material at the bottom of the butanol pre-distillation column 2 is pumped into the butanol distillation column 8 via the bottom pump 7. The butanol distillation column 8 is equipped with a butanol reboiler 9, using steam as its heat source. The top pressure of the butanol distillation column 8 is 92 kPa(G), the top temperature is 162℃, and the bottom temperature is 183℃. The vapor phase from the top of the butanol distillation column 8 enters the butanol isomer reboiler 21 for condensation. The condensed liquid enters the butanol distillation column reflux phase separator 10. The aqueous phase in the reflux phase separator 10 is discharged from the boundary area. The organic phase in the reflux phase separator 10 is pumped by the butanol distillation column reflux pump 11; part of it is returned to the top of the butanol distillation column 8 as reflux, and the other part is collected as a light component and returned to the butanol pre-distillation column 2. The heavy components at the bottom of the butanol distillation column 8 are collected by the bottom pump 12. The material collected from the side stream of the butanol distillation column 8 is divided into two streams after being collected by the butanol distillation column side stream pump 13. One stream enters the butanol isomer first column 14, and the other stream enters the butanol isomer second column 20.

[0169] The butanol isomer first column 14 is equipped with a butanol isomer first column reboiler 15, using the overhead vapor phase from the butanol isomer second column as the heat source for the butanol isomer first column reboiler; the overhead pressure of the butanol isomer first column 14 is -20 kPa(G), the overhead temperature is 85℃, and the bottom temperature is 109℃; the overhead vapor phase from the butanol isomer first column 14 enters the butanol isomer first column condenser 16 for condensation, using circulating water as the condenser coolant; the condensed liquid enters the butanol isomer first column reflux tank 17; the material in the butanol isomer first column reflux tank 17 is conveyed by the butanol isomer first column reflux pump 18, with part returning as reflux to the top of the butanol isomer first column 14, and part being collected as isobutanol product. The n-butanol product at the bottom of the butanol isomer first column 14 is transported to the n-butanol product tank by the butanol isomer first column bottom pump 19.

[0170] The butanol isomer secondary column 20 is equipped with a butanol isomer secondary column reboiler 21, using the overhead vapor phase from the butanol distillation column as the heat source for the reboiler. The overhead pressure of the butanol isomer secondary column 20 is 30 kPa(G), the overhead temperature is 128℃, and the bottom temperature is 145℃. The overhead vapor phase from the butanol isomer secondary column 20 enters the butanol isomer primary column reboiler 15 for condensation. The condensed liquid enters the butanol isomer secondary column reflux tank 22. The material in the butanol isomer secondary column reflux tank 22 is conveyed by the butanol isomer secondary column reflux pump 23, with part of it returning to the top of the butanol isomer secondary column 20 as reflux and part of it being collected as isobutanol product. The n-butanol product at the bottom of the butanol isomer secondary column 20 is pumped out to the n-butanol product tank by the butanol isomer secondary column bottom pump 24.

[0171] In the octanol separation process:

[0172] The mixed butyraldehyde (in which the ratio of n-butyraldehyde to isobutyraldehyde is approximately 13:1) is divided into two streams, one of which enters the butyraldehyde isomer tower 25 and the other enters the butyraldehyde isomer tower 31.

[0173] The butyraldehyde isomer first tower 25 is equipped with a butyraldehyde isomer first tower reboiler 26, using the top vapor phase of the butyraldehyde isomer second tower as the heat source for the butyraldehyde isomer first tower reboiler; the top pressure of the butyraldehyde isomer first tower 25 is -15 kPa(G), the top temperature is 67℃, and the bottom temperature is 81℃; the top vapor phase of the butyraldehyde isomer first tower 25 enters the butyraldehyde isomer first tower condenser 27 for condensation, using circulating water as the condenser refrigerant; the condensed liquid enters the butyraldehyde isomer first tower reflux phase separator 28; the material in the butyraldehyde isomer first tower reflux phase separator 28 is conveyed by the butyraldehyde isomer first tower reflux pump 29, with part returning as reflux to the top of the butyraldehyde isomer first tower 25, and part being collected as isobutanol or mixed butanol products. The material at the bottom of the butyraldehyde isomer first tower 25 is conveyed by the butyraldehyde isomer first tower bottom pump 30 to collect n-butyraldehyde.

[0174] The butyraldehyde isomer secondary column 31 is equipped with two reboilers: one is reboiler 32, which uses steam as its heat source; the other is reboiler 33, which uses the vapor from the top of the octanol distillation column as its heat source. The pressure at the top of the butyraldehyde isomer secondary column 31 is 180 kPa(G), the temperature at the top is 110℃, and the temperature at the bottom is 129℃. The vapor from the top of the butyraldehyde isomer secondary column 31 enters the reboiler 26 of the butyraldehyde isomer secondary column for condensation. The condensed liquid enters the reflux phase separator 34 of the butyraldehyde isomer secondary column. The aqueous phase in the reflux phase separator 34 is discharged from the boundary area. The organic phase in the reflux phase separator 34 is transported by the reflux pump 35 of the butyraldehyde isomer secondary column. Part of it is returned to the top of the butyraldehyde isomer secondary column 31 as reflux, and the other part is collected and sent to the isobutyraldehyde or mixed butyraldehyde storage tank. The material at the bottom of the butyraldehyde isomer secondary tower 31 is transported by the butyraldehyde isomer secondary tower bottom pump 36 to extract n-butyraldehyde.

[0175] Butyraldehyde is subjected to octanol reaction system 37, and after overall condensation and hydrogenation, crude octanol containing a small amount of impurities is obtained.

[0176] The material from the octanol reaction system is sent to the octanol pre-distillation column 38. The octanol pre-distillation column 38 is equipped with an octanol pre-distillation column reboiler 39, which uses steam as the heat source. The top pressure of the octanol pre-distillation column 38 is -10 kPa(G), the top temperature is 123℃, and the bottom temperature is 171℃. The vapor phase at the top of the octanol pre-distillation column 38 enters the octanol pre-distillation column condenser 40 for condensation. The condensed liquid enters the octanol pre-distillation column reflux phase separator 41. The aqueous phase in the octanol pre-distillation column reflux phase separator 41 is discharged from the boundary area. The organic phase in the octanol pre-distillation column reflux phase separator 41 is transported by the octanol pre-distillation column reflux pump 42. Part of it is returned to the top of the octanol pre-distillation column 38 as reflux, and part of it is collected as a light component.

[0177] The bottom product of the octanol pre-distillation column 38 is pumped to the octanol distillation column 44 via the octanol pre-distillation column bottom pump 43. The octanol distillation column 44 is equipped with an octanol reboiler 45, using steam as the heat source. The top pressure of the octanol distillation column 44 is -8 kPa(G), the top temperature is 143℃, and the bottom temperature is 182℃. The vapor phase from the top of the octanol distillation column 44 enters the butyraldehyde isomer reboiler 33 for condensation. The condensed liquid enters the octanol distillation column reflux tank 46. The material in the octanol distillation column reflux tank 46 is pumped by the octanol distillation column reflux pump 47, with a portion returning to the top of the octanol distillation column 44 as reflux and a portion being collected as octanol product. The bottom product of the octanol distillation column 44, as a heavy component, is collected via the octanol distillation column bottom pump 48.

[0178] Under the same feeding conditions, the energy consumption ratio is as follows:

[0179] Davy process 28874 Example 1 13112 0.45 Example 2 15126 0.52 Example 3 12497 0.43

[0180] In this invention, the overhead vapor phase of the butanol distillation column uses the reboiler of the butanol isomer II column as a heat source; the overhead vapor phase of the butanol isomer II column uses the reboiler of the butanol isomer I column as a heat source; the overhead vapor phase of the butyraldehyde isomer II column uses the reboiler of the butyraldehyde isomer I column as a heat source; and the overhead vapor phase of the octanol distillation column uses the reboiler of the butyraldehyde isomer II column as a heat source. This invention achieves triple-effect heat exchange coupling between the butanol separation process and the octanol separation process, which can significantly reduce the consumption of steam and cooling water, and reduce production energy consumption.

[0181] The triple-effect distillation method for butanol and octanol production in this invention sets up heat exchange for butanol separation and octanol separation processes respectively. The two processes can work separately for butanol separation and octanol separation, or they can be used together. When used together, the two processes use the same raw materials, and the ratio of the raw materials of the two processes can be arbitrarily allocated according to market conditions to produce the required butanol and octanol.

[0182] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A triple-effect distillation method for the production of butanol and octanol, comprising two processes: butanol separation and octanol separation, wherein the two processes use the same raw materials and, through different steps, yield n-butanol, isobutanol, and octanol products, respectively, characterized in that... The separation of butanol is divided into three parts in sequence: hydrogenation, removal of light and heavy components, and separation of normal and isomers; the separation of octanol is divided into three parts in sequence: separation of butyraldehyde and isomers, hydrogenation, and removal of light and heavy components. The removal of light and heavy components from butanol is completed by a butanol pre-distillation column and a butanol distillation column; the separation of positive and negative isomers from butanol isomers is completed by a butanol isomer first column and a butanol isomer second column; the separation of positive and negative isomers from butyraldehyde is completed by a butyraldehyde isomer first column and a butyraldehyde isomer second column; and the removal of light and heavy components from octanol is completed by an octanol pre-distillation column and an octanol distillation column. A mixture of n- and isobutyraldehyde is used as a raw material in the butanol separation process and / or octanol separation process; In the butanol separation process, the mixture of n- and isobutyraldehyde is hydrogenated to obtain a mixture of n- and isobutanol, i.e., crude butanol. The crude butanol first passes through a butanol pre-distillation column to remove light components and a butanol distillation column to remove light components, heavy components, and impurities. Then, it passes through two isomerization columns at different pressures to separate n-butanol and isobutanol, yielding n-butanol and isobutanol products. The pressure settings of the first and second butanol isomerization columns meet the requirements of balancing energy consumption and separation efficiency. Both the bottom of the butanol isomer I and the bottom of the butanol isomer II column produce n-butanol. Part of the material refluxed from the top of the butanol isomer I column is connected to the top inlet of the butanol isomer I column via a pipeline, and the other part is produced as isobutanol. Part of the material refluxed from the top of the butanol isomer II column is connected to the top inlet of the butanol isomer II column via a pipeline, and the other part is produced as isobutanol. In the octanol separation process, a mixture of n-butyraldehyde and isobutyraldehyde is separated into n-butyraldehyde and isobutyraldehyde by passing through two isomerization towers with different pressures. The n-butyraldehyde is then hydrogenated to obtain crude octanol. The crude octanol is then passed through an octanol pre-distillation tower and an octanol distillation tower to remove light components, heavy components, and impurities, yielding the octanol product. The butyraldehyde isomerization tower 1 and the butyraldehyde isomerization tower 2 have different pressures, with one tower having a higher pressure and the other a lower pressure. The top temperature of the higher-pressure tower is higher than the bottom temperature of the lower-pressure tower. After condensation, a portion of the vapor phase from the top of the butyraldehyde isomer II tower is collected and sent to the isobutyraldehyde or mixed butyraldehyde storage tank or refluxed to the feed inlet of the butanol reaction system. The material from the bottom of the tower is collected as n-butyraldehyde. A portion of the vapor phase from the top of the butyraldehyde isomer I tower is collected as isobutyraldehyde or mixed butyraldehyde product or refluxed to the feed inlet of the butanol reaction system. The material from the bottom of the butyraldehyde isomer I tower is collected as n-butyraldehyde. The overhead vapor phase of the butanol distillation column serves as a heat source for the butanol isomer II column, and the overhead vapor phase of the butanol isomer II column serves as a heat source for the butanol isomer I column; the overhead vapor phase of the octanol distillation column serves as a partial heat source for the reboiler of the butyraldehyde isomer II column, and the overhead vapor phase of the butyraldehyde isomer II column serves as a heat source for the reboiler of the butyraldehyde isomer I column. The top temperature of the butanol distillation column must be greater than the bottom temperature of the butanol isomer II column, and the top temperature of the butanol isomer II column must be greater than the bottom temperature of the butanol isomer I column, with a temperature difference of not less than 5℃. The top temperature of the octanol distillation column should be greater than the bottom temperature of the butyraldehyde isomer II column, and the top temperature of the butyraldehyde isomer II column should be greater than the bottom temperature of the butyraldehyde isomer I column, with a temperature difference of not less than 5℃. The butanol pre-distillation column has a top pressure of atmospheric pressure ~100 kPa(G), a top temperature of 70~140℃, and a bottom temperature of 100~170℃. The top pressure of the butanol distillation column is atmospheric pressure ~100 kPa(G), the top temperature is 90~170℃, and the bottom temperature is 110~190℃. The pressure at the top of the column for butanol isomers is -100 kPa(G) to atmospheric pressure, and the temperature at the top of the column is 20 to 100℃, while the temperature at the bottom of the column is 40 to 120℃. The pressure at the top of the butanol isomer two-column is -60 kPa(G) to 40 kPa(G), the temperature at the top of the column is 60 to 140 °C, and the temperature at the bottom of the column is 80 to 160 °C. The pressure at the top of the column for butyraldehyde isomer is -100 kPa(G) to atmospheric pressure, the temperature at the top of the column is 20~100℃, and the temperature at the bottom of the column is 40~120℃. The pressure at the top of the butyraldehyde isomer two-column is atmospheric pressure ~200kPa(G), the temperature at the top of the column is 40~140℃, and the temperature at the bottom of the column is 60~160℃. The pressure at the top of the octanol pre-distillation column is -100 kPa(G) to atmospheric pressure, the temperature at the top is 60~140℃, and the temperature at the bottom is 100~180℃. The pressure at the top of the octanol distillation column is -100 kPa(G) to atmospheric pressure, the temperature at the top is 90~160℃, and the temperature at the bottom is 110~190℃.

2. The method according to claim 1, characterized in that, The mixture of n-butyraldehyde and isobutyraldehyde has a ratio of 10:

1. The butanol pre-distillation column has a top pressure of 50 kPa(G), a top temperature of 99°C, and a bottom temperature of 133°C; the butanol distillation column has a top pressure of 50 kPa(G), a top temperature of 137°C, and a bottom temperature of 168°C; the butanol isomer one column has a top pressure of -60 kPa(G), a top temperature of 76°C, and a bottom temperature of 90°C; the butanol isomer two column has a top pressure of -15 kPa(G), and a top temperature of 1... The top pressure of the butyraldehyde isomer I column is -50 kPa(G), the top temperature is 55℃, and the bottom temperature is 70℃; the top pressure of the butyraldehyde isomer II column is 100 kPa(G), the top temperature is 80℃, and the bottom temperature is 98℃; the top pressure of the octanol pre-distillation column is -50 kPa(G), the top temperature is 80℃, and the bottom temperature is 146℃; the top pressure of the octanol distillation column is -50 kPa(G), the top temperature is 146℃, and the bottom temperature is 170℃. Alternatively, in the mixture of n-butyraldehyde and isobutyraldehyde, the ratio of n-butyraldehyde to isobutyraldehyde is 5:

1. The butanol pre-distillation column has a top pressure of 20 kPa(G), a top temperature of 82°C, and a bottom temperature of 113°C; the butanol distillation column has a top pressure of 20 kPa(G), a top temperature of 114°C, and a bottom temperature of 133°C; the butanol isomer one column has a top pressure of -78 kPa(G), a top temperature of 45°C, and a bottom temperature of 71°C; the butanol isomer two column has a top pressure of -45 kPa(G), a top temperature of... The top pressure of the butyraldehyde isomer 1 column is -98 kPa(G), the top temperature is 21°C, and the bottom temperature is 42°C; the top pressure of the butyraldehyde isomer 2 column is 50 kPa(G), the top temperature is 61°C, and the bottom temperature is 81°C; the top pressure of the octanol pre-distillation column is -88 kPa(G), the top temperature is 75°C, and the bottom temperature is 138°C; the top pressure of the octanol distillation column is -90 kPa(G), the top temperature is 97°C, and the bottom temperature is 153°C. Alternatively, in the mixture of n-butyraldehyde and isobutyraldehyde, the ratio of n-butyraldehyde to isobutyraldehyde is 13:

1. The butanol pre-distillation column has a top pressure of 96 kPa(G), a top temperature of 135°C, and a bottom temperature of 166°C; the butanol distillation column has a top pressure of 92 kPa(G), a top temperature of 162°C, and a bottom temperature of 183°C; the butanol isomer one column has a top pressure of -20 kPa(G), a top temperature of 85°C, and a bottom temperature of 109°C; and the butanol isomer two column has a top pressure of 30 kPa(G) and a top temperature of... The top pressure of the butyraldehyde isomer 1 column is -15 kPa(G), the top temperature is 67℃, and the bottom temperature is 81℃; the top pressure of the butyraldehyde isomer 2 column is 180 kPa(G), the top temperature is 110℃, and the bottom temperature is 129℃; the top pressure of the octanol pre-distillation column is -10 kPa(G), the top temperature is 123℃, and the bottom temperature is 171℃; the top pressure of the octanol distillation column is -8 kPa(G), the top temperature is 143℃, and the bottom temperature is 182℃. Under the same feed conditions, the energy consumption reduction ratios relative to the Davy process were 0.45%, 0.52%, and 0.43%, respectively.

3. A butanol and octanol production apparatus for performing the method of claim 1 or 2, characterized in that, The equipment includes a butanol pre-distillation column, a butanol distillation column, a butanol isomer 1 column, a butanol isomer 2 column, a butanaldehyde isomer 1 column, a butanaldehyde isomer 2 column, an octanol pre-distillation column, and an octanol distillation column, totaling 8 columns, each equipped with a corresponding condenser, reflux phase separator, and reboiler. The feed inlet of the butanol pre-distillation column is connected to the discharge outlet of the butanol reaction system; The bottom feed of the butanol pre-distillation column is connected to the feed of the butanol distillation column, and the top reflux of the butanol pre-distillation column is collected as a light component. The heavy components are collected from the bottom of the butanol distillation column, and the vapor phase at the top of the column is connected to the heat exchange inlet of the reboiler at the bottom of the butanol isomer secondary column. The heat exchange outlet of the reboiler at the bottom of the butanol isomer secondary column is connected to the reflux phase separator located at the top of the butanol distillation column for reflux at the top of the butanol distillation column. At the same time, the reflux material at the top of the butanol distillation column is connected to the feed inlet of the butanol pre-distillation column via a pipeline. The side feed outlets of the butanol distillation column are connected to butanol isomer tower 1 and butanol isomer tower 2, respectively. The reboiler of the butanol isomer 1 column is connected to the top of the butanol isomer 2 column for heat exchange, and n-butanol is extracted from the bottom of both the butanol isomer 1 column and the bottom of the butanol isomer 2 column. A portion of the material refluxed from the top of the butanol isomer tower is connected to the top inlet of the butanol isomer tower via a pipeline, while the other portion is extracted as isobutanol. A portion of the material refluxed from the top of the butanol isomer secondary column is connected to the top inlet of the secondary column via a pipeline, while the other portion is collected as isobutanol. The feed for both the butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 is from mixed butyraldehyde produced by the propylene carbonylation reaction. The reflux effluent from the top of both towers is isobutyraldehyde or mixed butyraldehyde is connected to the feed inlet of the butanol reaction system. The reboiler of the butyraldehyde isomer I column exchanges heat with the top of the butyraldehyde isomer II column, and the bottom of the butyraldehyde isomer I column and the bottom of the butyraldehyde isomer II column are connected to the inlet of the octanol pre-distillation column after passing through the octanol reaction system. The bottom reboiler of the butyraldehyde isomer two column exchanges heat with the top of the octanol distillation column; A portion of the material refluxed from the top of the octanol pre-distillation column is connected to the top inlet of the octanol pre-distillation column via a pipeline, while the other portion is used to collect light components. The bottom outlet of the octanol pre-distillation column is connected to the inlet of the octanol distillation column; the heavy components are collected from the bottom of the octanol distillation column, and the octanol is collected after condensation and reflux at the top of the column.

4. The butanol and octanol production equipment according to claim 3, characterized in that, The butyraldehyde isomer secondary tower is equipped with two reboilers connected in parallel. One is the first reboiler of the butyraldehyde isomer secondary tower, which uses steam as the heat source for the reboiler. The other is the second reboiler of the butyraldehyde isomer secondary tower, which uses the top gas phase of the octanol distillation column as the heat source. The feed for the butanol reaction system is mixed butyraldehyde from the propylene carbonylation reaction.

5. The butanol and octanol production equipment according to claim 3, characterized in that, Each tower is either a plate tower or a packed tower, and the flow parameter FP value of each tower is between 0.02 and 0.

2. When it is a packed tower, the internal components of the tower include packing, packing support rings and liquid distributors.

6. The butanol and octanol production equipment according to claim 3, characterized in that, The raw material can be a mixture of butyraldehyde, a product of the propylene carbonylation reaction, or a mixture with n-butyraldehyde and isobutyraldehyde as the main components.

Images