An energy integrated separation system for butyraldehyde isomer distillation and alcohol distillation

Abstract

The utility model belongs to chemical engineering separation technical field relates to a kind of butyl aldehyde isomer rectification and alcohol rectification energy integrated separation system.The separation system includes butyl aldehyde isomer one tower, butyl aldehyde isomer two towers, butyl aldehyde isomer three towers, alcohol rectification light tower, alcohol rectification heavy tower, condenser, reflux tank, reboiler and each connecting pipeline.Using the butyl aldehyde isomer rectification and alcohol rectification energy integrated separation system of the utility model, the energy consumption of butyl / octanol production can be greatly reduced on the basis of realizing the efficient heat exchange between tower and tower, so as to greatly reduce the cost of butyl / octanol production.

Description

Technical Field

[0001] This utility model belongs to the field of chemical separation technology and relates to an energy-integrated separation system for butyraldehyde isomer distillation and alcohol distillation. Background Technology

[0002] Butanol and octanol can be produced in the same unit using similar synthetic methods, hence the common name butanol and octanol. Butanol and octanol are important raw materials for the synthesis of fine chemical products, mainly used in the production of plasticizers, solvents, dehydrating agents, defoamers, dispersants, flotation agents, petroleum additives, and synthetic fragrances.

[0003] In existing technologies, carbonyl synthesis has become a mainstream process for the production of butanol / octanol in coal chemical enterprises due to its advantages of high efficiency, high selectivity, and environmental friendliness. In the carbonyl synthesis process for producing butanol / octanol, propylene gas and syngas are used as raw materials, and rhodium is used as a catalyst to generate mixed butyraldehyde. After separation of butyraldehyde isomers, n-butyraldehyde is obtained. The n-butyraldehyde is then hydrogenated to obtain crude butanol / octanol, which is further refined through distillation and other processes to obtain the final butanol / octanol product.

[0004] Distillation is a common purification method that utilizes the difference in boiling points of different components to gradually separate impurity components and obtain purified products by repeatedly heating and cooling the liquid mixture.

[0005] In the carbonyl synthesis process, the main component of mixed butyraldehyde is a mixture of n-butyraldehyde and isobutyraldehyde in a mass ratio of 5:1 to 10:1. At atmospheric pressure, n-butyraldehyde has a boiling point of 74℃, while isobutyraldehyde has a boiling point of 64℃. Since their boiling points are quite close, they are typically separated by distillation to obtain n-butyraldehyde that meets the requirements for butanol and octanol production. Current conventional single-column distillation operations for separating n-butyraldehyde and isobutyraldehyde involve high operating temperatures, large temperature differences between the top and bottom of the column, and low thermodynamic efficiency. Furthermore, the bottom of the column requires a continuous supply of high-quality steam to the reboiler, and the top vapor phase also requires a large amount of circulating water for cooling. The refrigerant and heating medium are both external utilities, resulting in high overall energy consumption and production costs.

[0006] Furthermore, unpurified crude butanol / octanol often contains a significant amount of impurities. To improve its purity and meet product grade requirements, it is necessary to purify the crude product through distillation to remove these impurities. The butanol / octanol distillation process involves two energy-intensive distillation columns, referred to as the light component removal column and the heavy component removal column. Light components, including unreacted organic matter, water, and dissolved gases, are removed at the top of the light component removal column; high-boiling-point heavy components are removed at the bottom of the heavy component removal column, yielding the final product at the top. When producing octanol, the temperature of the overhead gas in the octanol light component removal column is between 70 and 120°C under a vacuum of -90 to -50 kPa; when producing butanol, the pressure at the top of the butanol light component removal column is between 0 and 100 kPa, and the temperature is between 80 and 130°C. Both modes have a large latent heat of condensation in the overhead gas of the light-light removal tower, but there is currently a lack of effective means to recover and utilize this heat. Furthermore, the heat of the overhead gas in the light-light removal tower is mainly cooled by circulating water, which not only wastes potential energy but also consumes a large amount of circulating water.

[0007] Most existing butanol / octanol production units employ separate processes for separating butyraldehyde isomers and removing light and heavy components. Both refrigerants and heat transfer media are external utilities, and there is no heat exchange between the towers, resulting in high energy consumption and consequently high production costs. Therefore, recovering and utilizing latent heat in the production system to reduce energy consumption and achieve energy conservation, emission reduction, and low-carbon emissions is of great significance to coal chemical enterprises. Utility Model Content

[0008] The purpose of this invention is to address the problems of high energy consumption in the separation of butyraldehyde isomers, large energy losses in the butyraldehyde distillation unit, and high consumption of utilities such as circulating water and steam in the carbonyl synthesis process of butyraldehyde / octanol. This invention provides an integrated energy separation system for butyraldehyde isomer distillation and alcohol distillation, which can significantly reduce the energy consumption of butyraldehyde / octanol production while achieving efficient heat exchange between columns, thereby significantly reducing the cost of butyraldehyde / octanol production.

[0009] To achieve this objective, in a basic implementation scheme, this utility model provides an integrated energy separation system for butyraldehyde isomer distillation and alcohol distillation. The separation system includes a butyraldehyde isomer primary column, a butyraldehyde isomer secondary column, a butyraldehyde isomer tertiary column, an alcohol distillation column for removing light components, an alcohol distillation column for removing heavy components, a condenser, a reflux tank, a reboiler, and various connecting pipelines.

[0010] The butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 are connected in parallel to be used for the distillation and separation of mixed butyraldehyde feed from the propylene carbonylation reaction.

[0011] The butyraldehyde isomer three-tower system is used for the distillation and separation of a portion of the vapor-phase distillate feed from the top side streams of the butyraldehyde isomer one and two towers.

[0012] The alcohol distillation column for removing light alcohols is used for the distillation and separation of crude alcohol feed.

[0013] The alcohol distillation de-heavy column is used to further distill and separate a portion of the liquid distillate feed from the bottom of the alcohol distillation de-light column;

[0014] The butyraldehyde isomer tower 1, butyraldehyde isomer tower 2, butyraldehyde isomer tower 3, alcohol distillation light distillation tower, and alcohol distillation heavy distillation tower are each equipped with a gas phase outlet at the top of the tower. Each gas phase outlet is connected to a condenser through a pipeline. Each condenser is connected to a reflux tank through a pipeline and then back to the top of the tower.

[0015] Each of the butyraldehyde isomer tower 1, butyraldehyde isomer tower 2, butyraldehyde isomer tower 3, alcohol distillation light distillation tower, and alcohol distillation heavy distillation tower has a liquid phase outlet at the bottom of each tower. Each liquid phase outlet is connected to a reboiler through a pipeline, and each reboiler is connected back to the bottom of each tower through a pipeline.

[0016] in:

[0017] The condenser at the top of the butyraldehyde isomer tower is the first condenser, and the reboiler at the bottom of the butyraldehyde isomer tower is the first reboiler. The gas phase outlet of the butyraldehyde isomer tower is connected to the first condenser through one pipeline, and then to the first reboiler through another pipeline before being connected back to the first condenser.

[0018] The condenser at the top of the alcohol distillation column for removing light components is the second condenser, and the reboiler at the bottom of the butyraldehyde isomer three-column column is the second reboiler. The gas phase outlet of the alcohol distillation column for removing light components is connected to the second condenser through one pipeline, and then connected to the second reboiler through another pipeline before being connected back to the second condenser.

[0019] The relevant principles of this utility model are as follows:

[0020] In the carbonyl synthesis of butanol and octanol, n-butyraldehyde is used as a raw material. Considering that companies typically have a butyraldehyde production unit simultaneously to meet the demand for n-butyraldehyde, and that both the butyraldehyde and butanol production units are equipped with distillation systems for further separation and purification of intermediate raw materials and products, n-butyraldehyde has a boiling point of 74℃ at atmospheric pressure, while isobutyraldehyde has a boiling point of 64℃. Since their boiling points are quite close, conventional single-tower distillation methods for separating isomers suffer from high operating temperatures, large temperature differences between the top and bottom of the column, and low thermodynamic efficiency.

[0021] This invention innovatively transforms the traditional single-tower butyraldehyde isomer distillation into a three-tower distillation system consisting of a butyraldehyde isomerization tower, a butyraldehyde isomerization tower, and a butyraldehyde isomerization tower, each with different pressures and functions. The mixture of n-butyraldehyde and isobutyraldehyde first passes through the butyraldehyde isomerization tower and then the butyraldehyde isomerization tower to separate n-butyraldehyde and isobutyraldehyde, with n-butyraldehyde collected at the bottom of the first and second towers. The butyraldehyde isomerization tower has a higher pressure and a lower pressure, with the higher-pressure tower having a higher temperature at the top than at the bottom of the lower-pressure tower, exhibiting a significant temperature difference. The butyraldehyde isomerization tower 1 and tower 2 are equipped with side streams at the top. Because the side streams produce a mixed butyraldehyde ratio of 1:9 to 1:6 (n-butyraldehyde:isobutyraldehyde), the temperature difference between the top and bottom of the two towers described in this invention is lower than that of traditional double-effect distillation. This requires a lower bottom temperature in tower 2, effectively reducing the condensation effect of n-butyraldehyde, resulting in higher overall separation efficiency, lower overall energy consumption, and reduced system operating costs. A third tower, the isobutyraldehyde refining tower, is also included. It uses the side streams from towers 1 and 2 as raw materials, obtaining isobutyraldehyde at the top and returning the bottom stream to the crude butyraldehyde feed line or directly extracting the finished n-butyraldehyde product, depending on the material composition.

[0022] In the butanol / octanol distillation system, crude butanol / octanol obtained from the hydrogenation of n-butyraldehyde is then processed through an alcohol distillation light component removal column and an alcohol distillation heavy component removal column to remove light components, heavy components, and impurities, yielding the butanol / octanol product. Light components, including unreacted organic matter, water, and dissolved gases, are removed at the top of the alcohol distillation light component removal column; high-boiling-point heavy components are removed at the bottom of the alcohol distillation heavy component removal column, yielding the butanol / octanol product at the top. In octanol production mode, under a vacuum of -90 to -50 kPa, the temperature of the gas at the top of the octanol light component removal column is between 70 and 120 °C; in butanol production mode, the pressure at the top of the butanol light component removal column is between 0 and 100 kPa, and the temperature at the top is between 80 and 130 °C. In both production modes, the latent heat of condensation in the vapor phase at the top of the alcohol distillation light component removal column is significant, but currently, there is a lack of effective means to recover and utilize this heat. Meanwhile, the bottom temperature of the three-column system for butyraldehyde isomers is 40–90 °C. The top temperature of the distillation column for removing light components is higher than the bottom temperature of the three columns for butyraldehyde isomers, and there is a certain temperature difference, so there is a feasibility for heat exchange utilization.

[0023] The reboiler at the bottom of the two-tower butyraldehyde isomerization tower uses the top gas phase of the first butyraldehyde isomerization tower as a heat source, and the first and second butyraldehyde isomerization towers are thermally coupled; the third butyraldehyde isomerization tower is equipped with a second reboiler, which uses the top gas phase of the alcohol distillation light removal tower as a heat source, and the third butyraldehyde isomerization tower is thermally coupled with the alcohol distillation light removal tower.

[0024] In a preferred embodiment, this invention provides an energy-integrated separation system for butyraldehyde isomer distillation and alcohol distillation, wherein:

[0025] The reflux troughs at the top of the butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 are respectively the first reflux trough and the second reflux trough. Both the first reflux trough and the second reflux trough have phase separation functions. The separated aqueous phase is discharged as wastewater, and the separated organic phase flows back to the top of the butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 through pipelines, respectively; and / or

[0026] The bottom of both the butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 are connected to a pipeline for extracting n-butyraldehyde.

[0027] In a preferred embodiment, this invention provides an energy-integrated separation system for butyraldehyde isomer distillation and alcohol distillation, wherein:

[0028] The second reboiler at the bottom of the butyraldehyde isomer three-tower system is divided into multiple groups connected in parallel. One or any number of these groups are connected to the top of the alcohol distillation light removal tower and the second condenser via pipelines.

[0029] In a preferred embodiment, the present invention provides an energy-integrated separation system for butyraldehyde isomer distillation and alcohol distillation, wherein the reflux tank at the top of the alcohol distillation light-light removal tower is a third reflux tank, which has a phase separation function. The separated aqueous phase is discharged as wastewater, and the separated organic phase flows back to the top of the alcohol distillation light-light removal tower through a pipeline.

[0030] In a preferred embodiment, this invention provides an energy-integrated separation system for butyraldehyde isomer distillation and alcohol distillation, wherein:

[0031] The reflux trough at the top of the alcohol distillation deweighting column is also connected to a portion of the collected alcohol pipeline; and / or

[0032] The bottom of the alcohol distillation deweighting column is also connected to a pipeline that collects heavy components.

[0033] In a preferred embodiment, this invention provides an energy-integrated separation system for butyraldehyde isomer distillation and alcohol distillation, wherein:

[0034] A first valve is also installed on the pipeline connecting the gas phase outlet at the top of the butyraldehyde isomer tower to the first reboiler; and / or

[0035] A first shorting line for shorting the first condenser is also provided in parallel with the piping connecting the first reboiler and the first reflux tank, and a second valve is also provided on the first shorting line; and / or

[0036] A third valve is also installed on the pipeline connecting the first reboiler and the first condenser; and / or

[0037] A fourth valve is also installed on the pipeline connecting the gas phase outlet at the top of the butyraldehyde isomer tower to the first condenser.

[0038] In a preferred embodiment, this invention provides an energy-integrated separation system for butyraldehyde isomer distillation and alcohol distillation, wherein:

[0039] A fifth valve is also installed on the pipeline connecting the vapor outlet at the top of the alcohol distillation column to the second reboiler; and / or

[0040] A second short-circuit pipe for shorting the second condenser is also provided in parallel with the piping connecting the second reboiler and the third reflux tank; and a sixth valve is also provided on the second short-circuit pipe; and / or

[0041] A seventh valve is also installed on the pipeline connecting the second reboiler and the second condenser; and / or

[0042] An eighth valve is also installed on the pipeline connecting the gas phase outlet at the top of the alcohol distillation light removal column to the second condenser.

[0043] In a preferred embodiment, the present invention provides an energy-integrated separation system for butyraldehyde isomer distillation and alcohol distillation, wherein the alcohol is butanol and / or octanol.

[0044] The beneficial effect of this invention is that by utilizing the energy integration and separation system for butyraldehyde isomer distillation and alcohol distillation of this invention, the energy consumption of butyraldehyde / octanol production can be significantly reduced while achieving efficient heat exchange between columns, thereby significantly reducing the cost of butyraldehyde / octanol production.

[0045] Most existing butanol and octanol production units employ separate processes for separating butyraldehyde isomers and removing light and heavy components. These processes require a continuous supply of high-quality steam to the reboiler at the bottom of the towers, and a large amount of circulating water for cooling the vapor phase at the top. Both the refrigerant and heat transfer media are external utilities, and there is no heat exchange between the towers, resulting in high energy consumption and consequently high production costs. However, the top temperature of the butyraldehyde isomer I tower (70–140℃) is higher than the bottom temperature of the butyraldehyde isomer II tower (50–110℃), and the top temperature of the butanol / octanol distillation light component removal tower (70 / 80–120 / 130℃) is higher than the bottom temperature of the butyraldehyde isomer III tower (40–90℃). There is a certain temperature difference between each tower, approximately 10–30℃, thus demonstrating the feasibility of heat exchange between towers. To reduce energy consumption in the butyraldehyde isomer separation system and the butyraldehyde / octanol distillation system, and to recover and utilize the waste heat from the overhead vapor phase of the butyraldehyde isomer tower and the butyraldehyde / octanol distillation tower, this invention incorporates a second reboiler for the three butyraldehyde isomer towers. The bottom reboiler of the second butyraldehyde isomer tower uses the overhead vapor phase of the first butyraldehyde isomer tower as its heat source; the second reboiler of the third butyraldehyde isomer tower uses the overhead vapor phase of the butyraldehyde / octanol distillation tower for removing light components as its heat source. This achieves energy interaction between the first and second butyraldehyde isomer towers, and heat coupling and integration between the third butyraldehyde isomer tower and the butyraldehyde / octanol distillation tower for removing light components.

[0046] The beneficial effects of this utility model are specifically reflected in:

[0047] 1. This utility model replaces the traditional single-tower separation process for butyraldehyde isomers with a three-tower separation process. One tower is split into three: the first two towers have the same function but different operating conditions, with one tower at a higher pressure (tower one for butyraldehyde isomers) and the other at a lower pressure (tower two for butyraldehyde isomers). The top temperature of the high-pressure tower is higher than the bottom temperature of the low-pressure tower, and a certain temperature difference exists, allowing for double-effect heat exchange between the two towers. Tower two for butyraldehyde isomers operates under negative pressure, resulting in a lower overall operating temperature. The reboiler at the bottom of tower two uses the vapor phase from the top of tower one as a heat source, fully utilizing the residual heat from the top of tower one. Tower two no longer requires an additional heat source, saving both steam and circulating water, significantly reducing the energy consumption for butyraldehyde isomer separation.

[0048] 2. The butyraldehyde isomer first tower and butyraldehyde isomer second tower of this utility model are also provided with side streams at the top of the tower, which makes the temperature difference between the top and bottom of the first and second towers of butyraldehyde isomers lower, and the required bottom temperature of the second tower is reduced. This can effectively reduce the condensation effect of n-butyraldehyde, make the separation efficiency of the whole tower higher, the overall energy consumption lower, and effectively reduce the operating cost of the system.

[0049] 3. This utility model also includes a third tower for isobutyraldehyde isomer separation. The third tower uses the side stream from the top of the first and second butyraldehyde isomer towers as raw materials to refine and separate isobutyraldehyde. Isobutyraldehyde is collected from the top of the third tower, while the bottom stream is returned to the crude butyraldehyde feed line or directly collected as the finished product, n-butyraldehyde, depending on the material composition. The reboiler for the third butyraldehyde isomer tower uses the top vapor phase from the butyraldehyde / octanol distillation light-light-removal tower as a heat source, achieving heat coupling between the third butyraldehyde isomer tower and the butyraldehyde / octanol distillation light-light-removal tower. This not only recovers and utilizes the waste heat from the top of the butyraldehyde / octanol distillation light-light-removal tower but also reduces the energy consumption of the third butyraldehyde isomer tower.

[0050] 4. Both the butyraldehyde isomer tower and the butanol / octanol distillation tower for removing light gases are equipped with condensers at the top. In actual production, by adjusting the opening of the third / seventh valve, the ratio of the butyraldehyde isomer tower / (butanol / octanol) distillation tower top gas passing through the condenser after reboiler condensation is controlled. This ensures sufficient cooling of the top gas while maximizing the recovery and utilization of heat from the top gas of the butyraldehyde isomer tower / (butanol / octanol) distillation tower, reducing the use of circulating water and lowering the energy consumption of the butyraldehyde isomer tower / butyraldehyde isomer tower.

[0051] 5. This utility model can flexibly adjust the production mode of butanol or octanol according to market changes. The energy coupling method between the towers, the equipment used, and the specific energy integration implementation method are the same in both modes. Only by switching some processes and adjusting the system process operation parameters can the production mode be switched, which can conveniently and flexibly adapt to market changes. Attached Figure Description

[0052] Figure 1 The diagram illustrates the structural composition of the energy-integrated separation system for butyraldehyde isomer distillation and alcohol distillation of this invention. Detailed Implementation

[0053] An exemplary composition and structure of the energy-integrated separation system for butyraldehyde isomer distillation and alcohol distillation of this invention is as follows: Figure 1 As shown, it includes a butyraldehyde isomer tower 1, a butyraldehyde isomer tower 2, a butyraldehyde isomer tower 3, an alcohol distillation light-removal tower 4, an alcohol distillation heavy-removal tower 5, condensers (including a first condenser 7 and a second condenser 11), reflux tanks (including a first reflux tank 8, a second reflux tank 13, and a third reflux tank 12), reboilers (including a first reboiler 6, a second reboiler 9, and a third reboiler 10), valves (including a first valve F1, a second valve F2, a third valve F3, a fourth valve F4, a fifth valve F5, a sixth valve F6, a seventh valve F7, and an eighth valve F8), and various connecting pipelines.

[0054] Butyraldehyde isomer tower 1 and butyraldehyde isomer tower 2 are connected in parallel for distillation separation of mixed butyraldehyde feed from propylene carbonylation reaction.

[0055] The butyraldehyde isomer three-tower 3 is used for the rectification and separation of a portion of the gaseous distillate feed from the top side streams of butyraldehyde isomer one-tower 1 and butyraldehyde isomer two-tower 2.

[0056] Alcohol distillation column 4 is used for distillation separation of crude alcohol feed.

[0057] The alcohol distillation de-heavy column 5 is used for further distillation separation of a portion of the liquid distillate feed from the bottom of the alcohol distillation de-light column 4.

[0058] The top of each of the butyraldehyde isomer tower 1, butyraldehyde isomer tower 2, butyraldehyde isomer tower 3, alcohol distillation light distillation tower 4, and alcohol distillation heavy distillation tower 5 is equipped with a gas phase outlet for each gas phase distillate. Each gas phase outlet is connected to a condenser through a pipeline. Each condenser is connected to a reflux tank through a pipeline and then connected back to the top of each tower.

[0059] The bottom of each of the butyraldehyde isomer tower 1, butyraldehyde isomer tower 2, butyraldehyde isomer tower 3, alcohol distillation light distillation tower 4, and alcohol distillation heavy distillation tower 5 is equipped with liquid phase outlets for the distillate. Each liquid phase outlet is connected to a reboiler through a pipeline, and each reboiler is connected back to the bottom of the tower through a pipeline.

[0060] in:

[0061] The condenser at the top of column 1 of butyraldehyde isomer is the first condenser 7, and the reboiler at the bottom of column 2 of butyraldehyde isomer is the first reboiler 6. The gas phase outlet of column 1 of butyraldehyde isomer is connected to the first condenser 7 through one pipeline, and then to the first reboiler 6 through another pipeline, and then back to the first condenser 7.

[0062] The condenser at the top of the alcohol distillation column 4 for removing light components is the second condenser 11. The reboilers at the bottom of the butyraldehyde isomer three-column 3 are the second reboiler 9 and the third reboiler 10 connected in parallel. The gas phase outlet of the alcohol distillation column 4 is connected to the second condenser 11 through one pipeline, and then connected to the third reboiler 10 through another pipeline before being connected back to the second condenser 11.

[0063] The reflux troughs at the top of the butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 are respectively the first reflux trough 8 and the second reflux trough 13. Both the first reflux trough 8 and the second reflux trough 13 have phase separation functions. The separated aqueous phase is discharged as wastewater, and the separated organic phase flows back to the top of the butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 through pipelines. The bottom of the butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 are also connected to pipelines for collecting n-butyraldehyde.

[0064] The reflux trough at the top of the butyraldehyde isomer three-tower 3 is also connected to a pipeline for collecting isobutyraldehyde. The bottom of the butyraldehyde isomer three-tower 3 is also connected to a pipeline for collecting mixed butyraldehyde, which is connected back to the mixed butyraldehyde feed pipeline of butyraldehyde isomer one-tower 1 and butyraldehyde isomer two-tower 2. The reboiler at the bottom of the butyraldehyde isomer three-tower 3 is divided into a second reboiler 9 and a third reboiler 10 connected in parallel. The third reboiler 10 is connected to the top of the alcohol distillation light removal tower 4 and the second condenser 11 via pipeline.

[0065] The reflux tank at the top of the alcohol distillation light removal column 4 is the third reflux tank 12. The third reflux tank 12 has a phase separation function. The separated aqueous phase is discharged as wastewater, and the separated organic phase flows back to the top of the alcohol distillation light removal column 4 through the pipeline.

[0066] The reflux trough at the top of the alcohol distillation deweighting column 5 is also connected to a pipeline for collecting alcohol. The bottom of the alcohol distillation deweighting column 5 is also connected to a pipeline for collecting heavy components.

[0067] A first valve F1 is installed on the pipeline connecting the gas phase outlet at the top of column 1 (the butyraldehyde isomer tower) to the first reboiler 6. A third valve F3 is installed on the pipeline connecting the first reboiler 6 to the first condenser 7. A first short-circuit pipe for shorting the first condenser 7 and the third valve F3 is also installed in parallel with the pipeline connecting the first reboiler 6 and the first reflux tank 8. A second valve F2 is also installed on the first short-circuit pipe. A fourth valve F4 is installed on the pipeline connecting the gas phase outlet at the top of column 1 (the butyraldehyde isomer tower) to the first condenser 7.

[0068] A fifth valve F5 is installed on the pipeline connecting the vapor outlet at the top of the alcohol distillation column 4 (for removing light components) to the third reboiler 10. A seventh valve F7 is installed on the pipeline connecting the third reboiler 10 to the second condenser 11. A second short-circuit line for shorting the second condenser 11 and the seventh valve F7 is also installed in parallel with the pipeline connecting the third reboiler 10 and the third reflux tank 12. A sixth valve F6 is installed on this second short-circuit line. An eighth valve F8 is installed on the pipeline connecting the vapor outlet at the top of the alcohol distillation column 4 (for removing light components) to the second condenser 11.

[0069] The above separation system can be used for the separation and production of butanol and / or octanol. When separating and producing butanol, the alcohol distillation light-removal tower 4 is a butanol distillation light-removal tower, and the alcohol distillation heavy-removal tower 5 is a butanol distillation heavy-removal tower. The feed to the alcohol distillation light-removal tower 4 is crude butanol, and the top portion of the alcohol distillation heavy-removal tower 5 is collected as butanol. When separating and producing octanol, the alcohol distillation light-removal tower 4 is an octanol distillation light-removal tower, and the alcohol distillation heavy-removal tower 5 is an octanol distillation heavy-removal tower. The feed to the alcohol distillation light-removal tower 4 is crude octanol, and the top portion of the alcohol distillation heavy-removal tower 5 is collected as octanol.

[0070] An exemplary production method utilizing the above-described exemplary separation system is as follows:

[0071] The mixed butyraldehyde obtained from the carbonylation reaction of propylene during the production of butyraldehyde / octanol by carbonyl synthesis is fed in parallel to butyraldehyde isomer tower 1 and butyraldehyde isomer tower 2 for distillation separation, and n-butyraldehyde is collected from the bottom of butyraldehyde isomer tower 1 and butyraldehyde isomer tower 2.

[0072] Part of the vapor distillate collected from the top side stream of butyraldehyde isomer tower 1 and butyraldehyde isomer tower 2 is fed into butyraldehyde isomer tower 3 for rectification and separation, and isobutyraldehyde is collected from the top part of butyraldehyde isomer tower 3.

[0073] The crude butanol / octanol obtained from the hydrogenation reaction of n-butyraldehyde during the production of butanol / octanol by carbonyl synthesis is fed into alcohol distillation column 4 for distillation separation.

[0074] A portion of the liquid distillate collected from the bottom of the alcohol distillation light phase removal column 4 is fed into the alcohol distillation heavy phase removal column 5 for further distillation and separation. Butanol / octanol is collected from the top of the alcohol distillation heavy phase removal column 5, and heavy components are collected from the bottom.

[0075] During the operation of the separation system:

[0076] In the first reboiler 6, a portion of the vapor distillate from the top of column 1 (butyraldehyde isomer) is heated with a portion of the liquid distillate from the bottom of column 2 (butyraldehyde isomer).

[0077] In the third reboiler 10, a portion of the vapor distillate from the top of the alcohol distillation light removal column 4 is used to heat a portion of the liquid distillate from the bottom of the butyraldehyde isomer three-column 3.

[0078] The temperature at the top of column 1 for butyraldehyde isomers is 70-140℃ and the pressure is 50-200KPa; the temperature at the bottom of column 1 is 80-150℃ and the pressure is 60-220KPa.

[0079] The temperature at the top of column 2 for butyraldehyde isomers is 40-100℃ and the pressure is -30-30KPa; the temperature at the bottom of column 2 is 50-110℃ and the pressure is -20-50KPa.

[0080] The temperature at the top of the three-tower column 3 for butyraldehyde isomers is 30-80℃ and the pressure is 5-30KPa; the temperature at the bottom of the column is 40-90℃ and the pressure is 10-50KPa.

[0081] Furthermore, the top temperature of column 1 of the butyraldehyde isomer is 10-30℃ higher than the bottom temperature of column 2 of the butyraldehyde isomer isomer.

[0082] For butanol distillation

[0083] The top temperature of distillation column 4 for removing light components is 80-130℃, and the pressure is 0-100 kPa; the bottom temperature is 90-180℃, and the pressure is 10-110 kPa.

[0084] The top temperature of the distillation deweighting column 5 is 90-160℃, and the pressure is 0-100KPa; the bottom temperature is 120-180℃, and the pressure is 10-130KPa.

[0085] For octanol distillation

[0086] The top temperature of distillation column 4 for removing light components is 70-120℃, and the pressure is -90 to (-50) kPa; the bottom temperature is 80-160℃, and the pressure is -80 to (-40) kPa.

[0087] The top temperature of the distillation deweighting column 5 is 120-150℃ and the pressure is -90-(-50)KPa; the bottom temperature is 130-170℃ and the pressure is -80-(-40)KPa.

[0088] Furthermore, the top temperature of column 4 in the alcohol distillation light removal column is 10-30℃ higher than the bottom temperature of column 3 in the butyraldehyde isomer three-column system.

[0089] In the formal production process described above, one operational mode of the exemplary production method is as follows:

[0090] During the production process, both butyraldehyde isomer tower 1 and butyraldehyde isomer tower 2 are fed with mixed butyraldehyde from the propylene carbonylation reaction. The first valve F1 and the second valve F2 / third valve F3 are opened, while the fourth valve F4 is closed. The butyraldehyde solution at the bottom of tower 2 enters the first reboiler 6 at the bottom of tower 2 via pipeline. The gas phase from tower 1 enters the first reboiler 6 at the bottom of tower 2 via pipeline to provide heat for reboiling. After sufficient heat exchange, the butyraldehyde solution is converted into a gas phase and returned to the bottom of tower 2 via pipeline. The gas phase at the top of tower 1 is condensed and sent via pipeline to the first reflux tank 8 at the top of tower 1. After sufficient condensation and phase separation in the first reflux tank 8, the organic phase is pumped back to the top of the tower as top reflux, while the aqueous phase is discharged from the system as wastewater. In actual production, the opening of the third valve F3 can be flexibly adjusted according to the material temperature in the first reflux tank 8 at the top of butyraldehyde isomer tower 1 and the production load of butyraldehyde isomer tower 1 and butyraldehyde isomer tower 2. This controls the ratio of butyraldehyde isomer top gas passing through the first condenser 7 at the top of butyraldehyde isomer tower 1 after condensation in the first reboiler 6 at the bottom of butyraldehyde isomer tower 2. This ensures sufficient cooling of the top gas while maximizing the recovery and utilization of the heat from the top gas of butyraldehyde isomer tower 1, reducing circulating water consumption, and lowering the energy consumption of butyraldehyde isomer tower 2, all while matching the load of the two towers and ensuring production. Both butyraldehyde isomer tower 1 and butyraldehyde isomer tower 2 have side streams from the top. The side streams produce a mixture of butyraldehyde (n-butyraldehyde:isobutyraldehyde) at a ratio of 1:9 to 1:6, which is then fed to the feed pipeline of butyraldehyde isomer tower 3. Butyraldehyde is extracted from the bottom of both butyraldehyde isomer tower 1 and butyraldehyde isomer tower 2. The extracted butyraldehyde is then sent to the intermediate tank area or the hydrogenation system.

[0091] If fluctuations or abnormalities occur in the butyraldehyde isomer tower 2 during production, the energy coupling between butyraldehyde isomer tower 1 and butyraldehyde isomer tower 2 can be severed by opening the fourth valve F4 and closing the first valve F1, second valve F2, and third valve F3. This allows the first condenser 7 at the top of butyraldehyde isomer tower 1 to be activated, transferring the load to butyraldehyde isomer tower 1 and achieving single-tower operation. With proper unit load configuration, the first condenser 7 at the top of butyraldehyde isomer tower 1 generally does not need to be activated during normal production; it is only required during start-up or load adjustments.

[0092] During the production process, the feed for the butyraldehyde isomer three-tower 3 is a mixture of butyraldehyde and isobutyraldehyde, with a composition of 1:9 to 1:6, obtained from the top side streams of butyraldehyde isomer one tower 1 and butyraldehyde isomer two tower 2. Valve F5 (fifth valve), F6 (sixth valve), and F7 (seventh valve) are opened, while valve F8 is closed. The butyraldehyde solution at the bottom of tower 3 enters the third reboiler 10 of tower 3 via pipeline. The vapor phase from the top of the alcohol distillation light-light-removal tower 4 enters the third reboiler 10 via pipeline to provide heat for tower 3, performing the reboiling operation. After sufficient heat exchange, the butyraldehyde solution is converted into a vapor phase and returned to the bottom of tower 3 via pipeline. The vapor phase from the top of the alcohol distillation light-light-removal tower 4 is condensed and sent via pipeline to the third reflux tank 12 at the top of the alcohol distillation light-light-removal tower 4. The vapor phase from the top of column 3 of the butyraldehyde isomerization tower is condensed in a condenser and then enters the reflux tank. Part of it is pumped back to the top of column 3 as reflux, while the other part is collected as isobutyraldehyde product. The vapor phase from the top of column 4 of the alcohol distillation light component removal tower is condensed and sent to the third reflux tank 12 for complete condensation and phase separation. The organic phase is pumped back to the top of the tower as reflux, while the aqueous phase is discharged as wastewater. The bottom of column 4 of the alcohol distillation light component removal tower is connected to column 5 of the alcohol distillation heavy component removal tower. The bottom components, after the removal of light components, are sent to the feed line of column 5 of the alcohol distillation heavy component removal tower. After further removal of heavy components in column 5, the finished product, butanol / octanol, is collected at the top, while the heavy components at the bottom are discharged outside the system.

[0093] In actual production, the opening of the seventh valve F7 can be flexibly adjusted according to the material temperature in the third reflux tank 12 at the top of the alcohol distillation light removal tower 4 and the production load of the butyraldehyde isomer tower 3 and the alcohol distillation light removal tower 4. This controls the ratio of the top gas of the alcohol distillation light removal tower 4 passing through the second condenser 11 after condensation, to the ratio of not passing through the second condenser 11 at the top of the alcohol distillation light removal tower. This ensures sufficient cooling of the top gas and, under the premise of matching the load of the two towers and ensuring production, maximizes the recovery and utilization of the heat of the top gas of the alcohol distillation light removal tower 4, reduces the consumption of circulating water, and reduces the energy consumption of the butyraldehyde isomer tower 3.

[0094] During production, if any of the butyraldehyde isomer three-tower 3 or the alcohol distillation light-light-removal tower 4 experiences abnormal fluctuations, the energy coupling between the butyraldehyde isomer three-tower 3 and the alcohol distillation light-light-removal tower 4 can be severed by opening the eighth valve F8 and closing the fifth valve F5, sixth valve F6, and seventh valve F7. This disconnects the third reboiler 10 and activates the second reboiler 9 and the second condenser 11, allowing the two towers to operate independently and avoiding mutual interference. With appropriate unit load configuration, the second reboiler 9 of the butyraldehyde isomer three-tower 3 generally does not require steam during normal production, only needing to be activated during start-up or load adjustment.

[0095] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model is also intended to include these modifications and variations. The above embodiments or implementations are merely illustrative examples of this utility model, and it can also be implemented in other specific ways or forms without departing from its gist or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of this utility model should be defined by the appended claims, and any changes equivalent to the intent and scope of the claims should also be included within the scope of this utility model.

Claims

1. An energy-integrated separation system for butyraldehyde isomer distillation and alcohol distillation, characterized in that: The separation system includes a butyraldehyde isomer first tower, a butyraldehyde isomer second tower, a butyraldehyde isomer third tower, an alcohol distillation light component removal tower, an alcohol distillation heavy component removal tower, a condenser, a reflux tank, a reboiler, and various connecting pipelines. The butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 are connected in parallel to be used for the distillation and separation of mixed butyraldehyde feed from the propylene carbonylation reaction. The butyraldehyde isomer three-tower system is used for the distillation and separation of a portion of the vapor-phase distillate feed from the top side streams of the butyraldehyde isomer one and two towers. The alcohol distillation column for removing light alcohols is used for the distillation and separation of crude alcohol feed. The alcohol distillation de-heavy column is used to further distill and separate a portion of the liquid distillate feed from the bottom of the alcohol distillation de-light column; The butyraldehyde isomer tower 1, butyraldehyde isomer tower 2, butyraldehyde isomer tower 3, alcohol distillation light distillation tower, and alcohol distillation heavy distillation tower are each equipped with a gas phase outlet at the top of the tower. Each gas phase outlet is connected to a condenser through a pipeline. Each condenser is connected to a reflux tank through a pipeline and then back to the top of the tower. Each of the butyraldehyde isomer tower 1, butyraldehyde isomer tower 2, butyraldehyde isomer tower 3, alcohol distillation light distillation tower, and alcohol distillation heavy distillation tower has a liquid phase outlet at the bottom of each tower. Each liquid phase outlet is connected to a reboiler through a pipeline, and each reboiler is connected back to the bottom of each tower through a pipeline. in: The condenser at the top of the butyraldehyde isomer tower is the first condenser, and the reboiler at the bottom of the butyraldehyde isomer tower is the first reboiler. The gas phase outlet of the butyraldehyde isomer tower is connected to the first condenser through one pipeline, and then to the first reboiler through another pipeline before being connected back to the first condenser. The condenser at the top of the alcohol distillation column for removing light components is the second condenser, and the reboiler at the bottom of the butyraldehyde isomer three-column column is the second reboiler. The gas phase outlet of the alcohol distillation column for removing light components is connected to the second condenser through one pipeline, and then connected to the second reboiler through another pipeline before being connected back to the second condenser.

2. The separation system according to claim 1, characterized in that: The reflux troughs at the top of the butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 are respectively the first reflux trough and the second reflux trough. Both the first reflux trough and the second reflux trough have phase separation functions. The separated aqueous phase is discharged as wastewater, and the separated organic phase flows back to the top of the butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 through pipelines, respectively; and / or The bottom of both the butyraldehyde isomer tower 1 and the butyraldehyde isomer tower 2 are connected to a pipeline for extracting n-butyraldehyde.

3. The separation system according to claim 1, characterized in that: The second reboiler at the bottom of the butyraldehyde isomer three-tower system is divided into multiple groups connected in parallel. One or any number of these groups are connected to the top of the alcohol distillation light removal tower and the second condenser via pipelines.

4. The separation system according to claim 1, characterized in that: The reflux tank at the top of the alcohol distillation light phase removal column is the third reflux tank. The third reflux tank has a phase separation function. The separated aqueous phase is discharged as wastewater, and the separated organic phase flows back to the top of the alcohol distillation light phase removal column through pipeline.

5. The separation system according to claim 1, characterized in that: The reflux trough at the top of the alcohol distillation deweighting column is also connected to a portion of the collected alcohol pipeline; and / or The bottom of the alcohol distillation deweighting column is also connected to a pipeline that collects heavy components.

6. The separation system according to claim 1, characterized in that: A first valve is also installed on the pipeline connecting the gas phase outlet at the top of the butyraldehyde isomer tower to the first reboiler; and / or A first shorting line for shorting the first condenser is also provided in parallel with the piping connecting the first reboiler and the first reflux tank, and a second valve is also provided on the first shorting line; and / or A third valve is also installed on the pipeline connecting the first reboiler and the first condenser; and / or A fourth valve is also installed on the pipeline connecting the gas phase outlet at the top of the butyraldehyde isomer tower to the first condenser.

7. The separation system according to claim 1, characterized in that: A fifth valve is also installed on the pipeline connecting the vapor outlet at the top of the alcohol distillation column to the second reboiler; and / or A second short-circuit pipe for shorting the second condenser is also provided in parallel with the piping connecting the second reboiler and the third reflux tank; and a sixth valve is also provided on the second short-circuit pipe; and / or A seventh valve is also installed on the pipeline connecting the second reboiler and the second condenser; and / or An eighth valve is also installed on the pipeline connecting the gas phase outlet at the top of the alcohol distillation light removal column to the second condenser.

8. The separation system according to any one of claims 1-7, characterized in that: The alcohol is butanol and / or octanol.

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