Method and system for separating and purifying high carbon mixed alcohols

Abstract

This invention discloses a method and system for separating and purifying high-carbon mixed alcohols. The system includes a C5 alcohol pre-cutting column, a C5 alcohol separation column, a C5 alcohol refining column, a C6 alcohol separation column, a C6 alcohol refining column, a C7 alcohol separation column, a C7 alcohol refining column, a C8 alcohol separation column, a C8 alcohol refining column, a C9 alcohol separation column, a C10 alcohol separation column, a C10 alcohol refining column, a C11 alcohol separation column, and a C11 alcohol refining column, connected in ascending order of carbon number for sequential separation. By integrating heat pump distillation, negative pressure distillation, partitioned wall distillation, and heat coupling technology between multiple columns in the sequential separation process, this system effectively solves the problems of excessive energy consumption and difficulty in simultaneously ensuring product purity and yield when separating C5-C12 mixed alcohols.

Description

Technical Field

[0001] This invention relates to the field of mixed alcohol distillation technology, and specifically to a method and system for separating and purifying high-carbon mixed alcohols. Background Technology

[0002] Higher alcohols (generally referring to fatty alcohols with five or more carbon atoms) are important raw materials for fine chemicals, widely used in the synthesis of plasticizers, detergents, surfactants, and other high-value-added chemicals. With my country's economic development, the demand for higher alcohols and their downstream products continues to grow. Currently, the mainstream international method for producing higher alcohols is the α-olefin carbonyl synthesis method. Domestic enterprises commonly use the oil and fat hydrogenation method, but its raw materials are entirely dependent on imports, resulting in high costs. These two technological constraints severely limit my country's self-sufficiency in higher alcohols and the development of related industries. In recent years, with advancements in coal chemical technology, the technical route of preparing higher alcohols from coal via syngas or Fischer-Tropsch synthesis products has provided a new possibility for reducing dependence on imports, and its industrialization process is receiving increasing attention.

[0003] However, regardless of the synthetic route, the resulting products are typically high-carbon mixed alcohols with a wide carbon number distribution. To obtain high-purity monoalcohols that meet the requirements of high-end fine chemical manufacturing, efficient separation and purification technology is an indispensable key step. Currently, the main technical challenges in this separation stage are as follows: First, existing separation technologies are extremely energy-intensive and economically inefficient. The boiling points of high-carbon mixed alcohols are much higher than those of common low-carbon alcohols; for example, the atmospheric boiling point of dodecanol exceeds 250°C. Using traditional atmospheric distillation sequences for separation requires each column's reboiler to continuously provide a large amount of high-grade heat energy, resulting in energy costs accounting for a significant proportion of the overall production cost of the separation unit, severely impacting the process's economics. Although energy-saving technologies such as partitioned-wall distillation exist in chemical separation, their application in the fine separation of high-carbon alcohols remains insufficient. Furthermore, single energy-saving technologies have limited energy-saving effects on high-carbon alcohol systems with wide boiling ranges and multiple components, failing to fundamentally solve the high energy consumption problem.

[0004] Secondly, achieving the separation of high-purity monoalcohols with each carbon number from high-carbon mixed alcohols, and further distinguishing between primary and isoalcohols, remains a technical challenge in current industrial practice. High-carbon mixed alcohols have many components, wide boiling ranges, and relatively low volatility between alcohols with different carbon numbers, as well as between primary and isoalcohols with the same carbon number. Conventional distillation alone is insufficient to obtain high-purity single components. Existing separation technologies mostly focus on obtaining wide-fraction alcohol mixtures or can only separate a few single alcohols. For example, in the separation of structurally similar alkanes, although there are existing technologies that simplify the process using advanced techniques such as partitioned-wall columns, their target products are mostly wide-fractional-number fractions or single-carbon products, making it difficult to achieve fine separation carbon-by-carbon from C5 to C12. In particular, there is a lack of mature solutions for simultaneously achieving efficient distribution and recovery of primary and isoalcohols with different carbon numbers within the same process. Therefore, developing a high-carbon mixed alcohol separation and purification method that can balance low energy consumption and high separation accuracy is of urgent significance for improving the level of fine processing of coal-based compounds in my country. Summary of the Invention

[0005] This invention provides a method and system for separating and purifying high-carbon mixed alcohols, thereby solving the technical problem that existing technologies cannot simultaneously achieve high purity, high yield, and low energy consumption in the industrial-scale separation of primary and isomer alcohols of various carbon numbers from C5-C12 mixed alcohols.

[0006] In a first aspect, the present invention provides a separation and purification system for high-carbon mixed alcohols, the separation and purification system comprising a C5 alcohol pre-cutting tower, a C5 alcohol separation tower, a C5 alcohol refining tower, a C6 alcohol separation tower, a C6 alcohol refining tower, a C7 alcohol separation tower, a C7 alcohol refining tower, a C8 alcohol separation tower, a C8 alcohol refining tower, a C9 alcohol separation tower, a C10 alcohol separation tower, a C10 alcohol refining tower, a C11 alcohol separation tower, and a C11 alcohol refining tower, connected in ascending order of carbon number for sequential separation;

[0007] The C5 alcohol separation tower is a heat pump distillation tower. The gas phase at the top of the tower is compressed and heated by a heat pump compressor and then used as the heat source for the reboiler in the bottom of the tower. The C5 alcohol refining tower, C9 alcohol separation tower, C11 alcohol separation tower, and C11 alcohol refining tower are negative pressure distillation towers.

[0008] In one optional embodiment, the C9 alcohol separation column is a partitioned-wall distillation column, with vertical baffles dividing the column into a pre-fractionation side and a main column side. The partitioned-wall distillation column has a C9 isomeric alcohol outlet at the top, a C9 n-primary alcohol side stream outlet in the middle of the main column side, and a C10 and above heavy fraction outlet at the reboiler. The partitioned-wall distillation column integrates the pre-fractionation column with the main column, not only achieving heat recycling within the column and significantly reducing equipment energy consumption, but also eliminating the need for a reboiler and a top condenser, thus reducing equipment investment costs and operating expenses.

[0009] In one optional embodiment, the top vapor outlet of the C8 alcohol separator is connected to the hot-side inlet of the reboiler in the bottom of the C6 alcohol refining column; this connection allows the condensation heat of the top stream from the C8 alcohol separator to be directly used to heat the bottom of the C6 alcohol refining column. And / or, the vapor outlet of the C10 alcohol refining column is connected to the hot-side inlet of the reboiler in the C10 alcohol separator. This connection allows the condensation heat of the overhead stream from the C10 alcohol refining column to be directly used to heat the reboiler of the C10 alcohol separator.

[0010] In one optional embodiment, the bottoms of the C5 alcohol separation tower, the C6 alcohol refining tower, and the C10 alcohol separation tower are each equipped with two sets of reboilers; wherein, the heat source of one set of reboilers is steam and / or heat transfer oil, and the heat source of the other set of reboilers comes from the waste heat of the top steam recovered in the system. And / or, the top of the C5 alcohol refining tower, C9 alcohol separation tower, C11 alcohol separation tower and C11 alcohol refining tower are all equipped with tail gas condensers for deep condensation of the gas phase at the top of the tower, so as to fully recover the entrained liquid monool products and improve the total product yield.

[0011] In one optional embodiment, a compressor inlet buffer tank is provided before the inlet of the heat pump compressor of the C5 alcohol separation tower; the outlet of the heat pump compressor is connected to the hot side inlet of the reboiler of the C5 alcohol separation tower; the hot side outlet of the reboiler of the C5 alcohol separation tower is connected to the inlet of the reflux tank at the top of the C5 alcohol separation tower; the outlet of the reflux tank at the top of the tower is connected to a reflux pump, and the outlet pipeline of the reflux pump is divided into two paths, one returning to the top of the C5 alcohol separation tower, and the other connecting to the feed inlet of the C5 alcohol refining tower; this structure realizes a complete cycle of heat pump distillation; And / or, the top of the C5 alcohol refining column is connected to a vacuum pump via a pipeline; the top of the C5 alcohol refining column is also connected in sequence to a water cooler, a C5 alcohol refining column top reflux tank and a tail gas condenser via a top discharge pipeline.

[0012] In one optional embodiment, the raw material processed by the system, a mixture of high-carbon alcohols, originates from syngas-to-high-carbon alcohols, α-olefin-to-high-carbon alcohols, Fischer-Tropsch synthesis oil by-products, and other secondary petroleum processing or coal processing. Its main components are a mixture of aliphatic n-type primary alcohols and aliphatic isomers containing five or more carbon atoms. This raw material requires pretreatment such as deacidification and dehydration before entering the system.

[0013] In one alternative embodiment, the C5 alcohol pre-cutting column is configured to separate the C5 alcohol and a small amount of C6 components from the feedstock from the top of the column, while discharging most of the C6 and heavier components from the bottom of the column. This incomplete separation strategy helps to reduce the operating load of the column and subsequent towers.

[0014] Secondly, the present invention also provides a method for separating and purifying high-carbon mixed alcohols, wherein the above-mentioned high-carbon mixed alcohol separation and purification system is used to separate and purify mixed alcohol raw materials containing C5~C12 fatty alcohols.

[0015] In one alternative implementation, the following steps are included: (1) A mixed alcohol feedstock containing C5~C12 fatty alcohols is fed into a C5 alcohol pre-cutting column to separate the overhead stream a and the bottom stream b; wherein, the overhead stream a contains C5 alcohol and a small amount of C6 alcohol, and the bottom stream b contains C6 alcohol and the above alcohol components. (2) The overhead stream a is fed into the C5 alcohol separation tower for separation to obtain overhead stream c and bottom stream d; wherein, overhead stream c is C5 alcohol and bottom stream d is a small amount of C6 alcohol; the C5 alcohol pre-cutting tower adopts the method of incomplete separation of C6 alcohol, which reduces the gas phase load of the C5 alcohol pre-cutting tower and the load of the subsequent C5 alcohol separation tower, thus saving more energy. The overhead stream c is fed into a C5 alcohol purification column for separation. C5 isomer alcohol is separated at the top of the column, and C5 normal primary alcohol is obtained at the bottom of the column. (3) The bottom stream b is fed into a C6 alcohol separation column for separation to obtain the top stream e and the bottom stream f; wherein, the top stream e is C6 alcohol and the bottom stream f contains C7 alcohol and above alcohol components. The overhead stream e is fed into a C6 alcohol purification column for separation. C6 isomer alcohol is separated at the top of the column, and C6 normal primary alcohol is obtained at the bottom of the column. The C6 isomer alcohol is mixed with the bottom stream d and discharged. (4) The bottom stream f is fed into a C7 alcohol separation column for separation to obtain the top stream g and the bottom stream h; wherein the top stream g is C7 alcohol and the bottom stream h contains C8 alcohol and above alcohol components. The overhead stream g was fed into a C7 alcohol purification column for separation. C7 isomer alcohols were separated at the top of the column, and C7 normal primary alcohols were obtained at the bottom of the column. (5) The bottom stream h is fed into a C8 alcohol separation column for separation to obtain the top stream i and the bottom stream j; wherein, the top stream i is C8 alcohol and the bottom stream j contains C8 alcohol and above alcohol components. The overhead stream i is fed into a C8 alcohol purification column for separation. C8 isomer alcohols are separated at the top of the column, and C8 normal primary alcohols are obtained at the bottom of the column. (6) The bottom stream j is fed into a C9 alcohol separation column for separation to obtain C9 isomer alcohol, C9 normal primary alcohol and bottom stream k; wherein, bottom stream k contains C10 alcohol and above alcohol components. (7) The bottom stream k is fed into a C10 alcohol separation column for separation to obtain the top stream m and the bottom stream n; wherein, the top stream m is C10 alcohol and the bottom stream n contains C11 alcohol and above alcohol components. The overhead stream m is fed into a C10 alcohol purification column for separation. C10 isomer alcohols are separated at the top of the column, and C10 normal primary alcohols are obtained at the bottom of the column. (8) The bottom stream n is fed into a C11 alcohol separation column for separation to obtain the top stream p and the bottom stream q; wherein, the top stream p is C11 alcohol, and the bottom stream q contains C12 alcohol and above alcohol components; the bottom stream q is produced as a heavy component of C12 and above. The overhead stream p is fed into a C11 alcohol purification column for separation. C11 isomer alcohols are separated at the top of the column, and C11 normal primary alcohols are obtained at the bottom of the column.

[0016] In an optional embodiment, in step (2), when the C5 alcohol separation tower is performing separation, the gas phase at the top of the tower is compressed by a heat pump compressor and used as the heat source for the reboiler of the tower. And / or, in step (2), the separation is carried out in the C5 alcohol purification column under vacuum conditions; And / or, in step (6), the separation is carried out in the C9 alcohol separation tower under vacuum conditions; And / or, in step (8), when separation is carried out in the C11 alcohol separation tower and / or the C11 alcohol refining tower, the operation is carried out under vacuum conditions.

[0017] In an optional embodiment, in step (6), the separation of the C9 alcohol is carried out in a distillation column, the C9 isomer alcohol is drawn from the top of the column, the C9 normal primary alcohol is drawn from the side stream of the main column, and the bottom stream k is drawn from the bottom of the column.

[0018] In an optional embodiment, in step (5), the condensation heat of the overhead stream i of the C8 alcohol separation tower is used as the heat source for the reboiler of the C6 alcohol refining tower; while recovering and utilizing the waste heat at the top of the C8 alcohol separation tower, the overhead material is condensed to reach the appropriate temperature for top reflux. The coupling of waste heat recovery and utilization between different towers in this invention not only improves the thermal efficiency of the device but also reduces the consumption of bottom steam and top cooling water, thereby reducing the energy consumption of the device.

[0019] And / or, in step (7), the condensation heat of the overhead stream from the C10 alcohol refining column is used as the heat source for the reboiler of the C10 alcohol separation column. While recovering the waste heat from the top of the C10 alcohol refining column, the overhead material is condensed, reaching a suitable temperature for the overhead reflux. This invention couples waste heat recovery and utilization between different columns, which not only improves the thermal efficiency of the device but also reduces the consumption of bottom steam and top cooling water, thereby reducing the energy consumption of the device.

[0020] In one optional embodiment, the recovery rate of each carbon number monool product (C5~C11 n-type primary alcohol and iso-type alcohol) obtained by the method is higher than 95%, and the purity can reach 99%.

[0021] In an optional embodiment, when using heat pump distillation technology in step (2), C5 alcohol flows out from the top of the C5 alcohol separation column, enters the heat pump compressor through the compressor inlet buffer tank for adiabatic compression and heating, and serves as the heat source for the reboiler of the column. Simultaneously, the C5 alcohol undergoes heat exchange and condensation, then enters the column top reflux tank. After being pressurized by the column top reflux pump, it is divided into two streams: one stream is cooled and returned to the C5 alcohol separation column, and the other stream enters the C5 alcohol refining column. The stream returning to the C5 alcohol separation column serves as the distillation reflux liquid to maintain a stable gas-liquid balance and separation efficiency within the column; the stream entering the C5 alcohol refining column serves as the feed to continue the separation of C5 isomer alcohols and normal primary alcohols. This splitting method is the standard operation for the heat pump distillation column to achieve continuous and stable operation and downstream material transfer.

[0022] In an optional embodiment, when cross-tower thermal coupling is applied in step (5), C8 alcohol flows out from the top of the C8 alcohol separation tower as a heat source for the reboiler of the C6 alcohol refining tower. At the same time, C8 alcohol undergoes heat exchange and condensation, and then enters the top reflux tank of the C8 alcohol separation tower. After being pressurized by the top reflux pump, it is divided into two streams, one returning to the C8 alcohol separation tower and the other entering the C8 alcohol refining tower.

[0023] In an optional embodiment, when cross-tower thermal coupling is applied in step (7), the C10 isomeric alcohol flows out from the top of the C10 alcohol refining tower as a heat source for the reboiler of the C10 alcohol separation tower. At the same time, the C10 isomeric alcohol undergoes heat exchange and condensation, and then enters the top reflux tank of the C10 alcohol refining tower. After being pressurized by the top reflux pump, it is divided into two streams, one of which returns to the C10 alcohol refining tower, and the other of which is used as the product C10 isomeric alcohol exit device.

[0024] In an optional implementation, when negative pressure distillation technology is used in step (2), the C5 alcohol refining column controls the operating pressure within a preset negative pressure range through a vacuum pump installed at the top of the column.

[0025] In an optional implementation, when negative pressure distillation technology is used in step (6), the C9 alcohol separation column controls the operating pressure within a preset negative pressure range through a vacuum pump installed at the top of the column.

[0026] In an optional implementation, when negative pressure distillation technology is used in step (8), the C11 alcohol separation column and the C11 alcohol refining column are respectively controlled to operate within a preset negative pressure range by vacuum pumps installed at their respective tops. Compared with atmospheric pressure distillation, negative pressure distillation technology achieves better separation efficiency at lower operating temperatures, requires less equipment investment, and consumes less energy.

[0027] In addition, the technical solution of the present invention also includes other optional embodiments not described, such as adjusting the number of towers according to the raw material composition (e.g., omitting towers with odd carbon numbers) and optimizing the operating parameters of each tower (e.g., pressure, temperature, reflux ratio), etc., all of which fall within the protection scope of the present invention.

[0028] Specifically, this invention aims to overcome the technical bottlenecks of low separation purity and high system energy consumption caused by the low relative volatility, wide boiling range, and complex phase equilibrium of higher carbon alcohol components. By integrating multiple advanced separation technologies such as heat pump distillation, negative pressure distillation, partitioned column, and cross-tower thermal coupling, and designing a process flow for fine separation of normal / isomeric alcohols by carbon number sequence, this invention achieves for the first time the efficient and energy-saving simultaneous acquisition of high-purity (up to 99%) C5~C12 single series of normal primary alcohols and isomers from high carbon mixed alcohols.

[0029] The raw material, a mixture of high-carbon alcohols, is separated into individual monools according to the order of carbon chain length, namely, C5 n-primary alcohol (n-C5OH), C6 n-primary alcohol (n-C6OH), C7 n-primary alcohol (n-C7OH), C8 n-primary alcohol (n-C8OH), C9 n-primary alcohol (n-C9OH), C10 n-primary alcohol (n-C10OH), and C11 n-primary alcohol (n-C11OH); the separated isomers... The alcohol products include C5 isomers (i-C5OH), C6 isomers (i-C6OH), C7 isomers (i-C7OH), C8 isomers (i-C8OH), C9 isomers (i-C9OH), C10 isomers (i-C10OH), C11 isomers (i-C11OH), and C12 and above mixed alcohols (C12+). Each isomer is a monool or a mixture of 1 to 3 isomers with the same number of carbon atoms.

[0030] The technical solution of this invention has the following advantages: 1. A separation and purification system for high-carbon mixed alcohols, the separation and purification system comprising a C5 alcohol pre-cutting column, a C5 alcohol separation column, a C5 alcohol refining column, a C6 alcohol separation column, a C6 alcohol refining column, a C7 alcohol separation column, a C7 alcohol refining column, a C8 alcohol separation column, a C8 alcohol refining column, a C9 alcohol separation column, a C10 alcohol separation column, a C10 alcohol refining column, a C11 alcohol separation column, and a C11 alcohol refining column, connected in ascending order of carbon number for sequential separation; wherein, the C5 alcohol separation column is a heat pump distillation column, the vapor phase at the top of the column is compressed and heated by a heat pump compressor and used as the heat source for the reboiler of the column; the C5 alcohol refining column, the C9 alcohol separation column, the C11 alcohol separation column, and the C11 alcohol refining column are negative pressure distillation columns. The separation and purification system proposed in this invention consists of fourteen columns connected in series, from a C5 alcohol pre-cutting column to a C11 alcohol refining column. The C5 alcohol separation column is designed as a heat pump distillation column, with its overhead vapor phase compressed and directly used as a heat source for its own reboiler. The refining columns for C5, C9, and C11 alcohols, as well as the C9 separation column, operate under negative pressure. Traditionally, separating wide-boiling-range, multi-component alcohol mixtures like C5-C12 often requires multiple columns connected in series, resulting in huge steam consumption. Furthermore, higher alcohols are prone to decomposition at high temperatures, making it difficult to balance product purity and yield. This solution fundamentally adjusts the process design: firstly, a heat pump is used in the C5 column, which has the lowest boiling point, to "pump" the heat that would otherwise be wasted at the top of the column back to heat the reboiler, significantly saving steam; secondly, for alcohols like C9 and C11, which require higher temperatures for separation, vacuum is used to lower their boiling points. This avoids coking or decomposition caused by high temperatures and increases the relative volatility between components, making separation easier and more thorough. In this way, the entire system not only has a significant advantage in energy consumption compared to traditional processes, but can also stably produce n- and iso-alcohols with a purity of over 99% and a yield of over 95% for C5 to C12 carbon numbers, truly realizing a feasible, economical, and efficient fine separation of all components from the laboratory to industrial equipment.

[0031] 2. This invention designs the C9 alcohol separation column as a partitioned-wall distillation column, primarily because the separation of C9 alcohols is the most complex among the C5-C12 high-carbon alcohol systems. Firstly, C9 alcohols themselves exist as normal alcohols and various isomers (such as 2-ethylhexanol, 3,5,5-trimethylhexanol, etc.). These isomers have very similar boiling points and relatively low volatility, making it difficult for ordinary distillation columns to separate them efficiently. Secondly, the boiling point difference between C9 normal alcohols and their adjacent C10 alcohols is small, making them prone to entrainment and further increasing the separation difficulty. If a traditional multi-column series scheme is used, it not only requires multi-stage column equipment and consumes a lot of energy, but the separation effect is still unsatisfactory. This solution employs a partitioned distillation column for the C9 alcohol separation stage. A vertical partition within the column divides the column into a pre-fractionation side and a main column side. By achieving multi-stage separation within the same column, the three products—C9 isomer alcohols, C9 n-primary alcohols, and C10 and higher heavy components—are precisely separated in one step, and collected from the top, main column side stream, and bottom stream, respectively. This solves the problem of separating C9 series alcohols due to their similar boiling points and numerous isomers, while avoiding the increased equipment investment and energy consumption caused by adding additional columns. It significantly simplifies the process while ensuring separation purity, saving at least one bottom reboiler and top condenser system, thereby substantially reducing equipment investment costs and plant footprint. Furthermore, the energy consumption of this separation stage is further reduced through heat integration within the column.

[0032] 3. This invention further connects the overhead stream of the C8 alcohol separation column to the reboiler of the C6 alcohol refining column, and similarly, the overhead stream of the C10 alcohol refining column can be connected to the reboiler of the C10 alcohol separation column. This cross-column thermal coupling design breaks the traditional energy consumption pattern of each column operating independently. In the traditional process, the heat of the steam at the top of the high-temperature column is wasted by the cooling water, while the reboiler of the low-temperature column requires additional steam heating, resulting in significant energy waste. This design directly uses the condensation heat of the steam at the top of the high-boiling-point column (such as the C8 column) to heat the reboiler of the lower-boiling-point column (such as the C6 column), achieving "cascade utilization" and "on-site reuse" of energy. This is equivalent to turning the waste heat that would otherwise be discharged into a useful heat source, greatly improving the thermal efficiency of the entire system.

[0033] 4. To further enhance operational flexibility and energy recovery efficiency, this invention incorporates two sets of reboilers in the reboilers of the C5 alcohol separation tower, C6 alcohol refining tower, and C10 alcohol separation tower. One set uses steam or heat transfer oil as the main heat source to ensure start-up and stable operation; the other set is specifically used to recover waste heat from the tops of other towers within the system as a heat source. This ensures the stability and reliability of the unit under various operating conditions while maximizing the utilization of low-grade heat energy generated within the system, reducing dependence on external steam or heat transfer oil, making the energy utilization of the entire system more economical and rational, and further reducing operating costs.

[0034] 5. Considering that the overhead gas phase is more likely to carry over valuable light component product vapors during negative pressure operation, this invention specifically installs tail gas condensers at the top of each refining and separation tower (C5, C9, C11, etc.) operating under negative pressure. This allows for deep condensation of the overhead gas, bringing back trace amounts of mono-alcohol products that might still be carried away by the gas after conventional condensation. This effectively reduces the intangible losses of high-value-added products, directly increases the final total yield of each mono-alcohol product, makes the entire separation process more efficient, and improves the overall economic benefits of the project.

[0035] 6. This invention also provides a separation and purification method that is perfectly matched with the system. This method ensures that the energy-saving advantages of the heat pump and the advantages of negative pressure for the gentle and efficient separation of higher alcohols can be fully utilized in actual production, avoiding the significant reduction in effectiveness due to improper use of advanced equipment, thereby transforming the system's design potential into stable and excellent industrial production indicators. Ultimately, through the synergy of the system and the method, it is possible to stably obtain primary and isomeric alcohols of C5 to C11 carbon numbers with a purity of not less than 99% and a yield of more than 95%, thus solving the industry problem of the difficulty in simultaneously achieving high purity, high yield, and low energy consumption. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a schematic flow chart of the high-carbon mixed alcohol separation and purification process of Embodiment 1 of the present invention (C5~C8 alcohol separation section). Figure 2 This is a schematic flow diagram of the high-carbon mixed alcohol separation and purification process in Embodiment 1 of the present invention (C9~C11 alcohol separation section).

[0038] Explanation of reference numerals in the attached figures: 1. C5 alcohol pre-cutting tower; 2. C5 alcohol separation tower; 3. C5 alcohol refining tower; 4. C6 alcohol separation tower; 5. C6 alcohol refining tower; 6. C7 alcohol separation tower; 7. C7 alcohol refining tower; 8. C8 alcohol separation tower; 9. C8 alcohol refining tower; 10. C9 alcohol separation tower; 11. C10 alcohol separation tower; 12. C10 alcohol refining tower; 13. C11 alcohol separation tower; 14. C11 alcohol refining tower; 15. Compressor inlet buffer tank; 16. Heat pump compressor; 17. C5 alcohol separation tower top reflux tank; 18. C5 alcohol separation tower top reflux pump; 19. C5 20. Reflux water cooler for C5 alcohol separation column; 21. Reboiler for C5 alcohol separation column; 22. Reheat reboiler for C5 alcohol separation column; 23. Reboiler pump for C5 alcohol separation column; 24. Top water cooler for C5 alcohol refining column; 25. Top reflux tank for C5 alcohol refining column; 26. Tail gas condenser for C5 alcohol refining column; 27. Vacuum pump for C5 alcohol refining column; 28. Top reflux pump for C5 alcohol refining column; 29. ​​Reboiler for C6 alcohol refining column; 30. Reheat reboiler for C6 alcohol refining column; 31. Reboiler pump for C6 alcohol refining column; 32. C6 alcohol... 33. C7 alcohol separation tower reboiler pump; 34. C8 alcohol separation tower overhead reflux tank; 35. C8 alcohol separation tower overhead reflux pump; 36. C8 alcohol separation tower reboiler pump; 37. C9 alcohol separation tower overhead water cooler; 38. C9 alcohol separation tower overhead reflux tank; 39. C9 alcohol separation tower tail gas condenser; 40. C9 alcohol separation tower vacuum pump; 41. C9 alcohol separation tower overhead reflux pump; 42. C9 alcohol separation tower reboiler pump; 43. C10 alcohol separation tower reboiler; 44. C10 alcohol separation tower waste heat reboiler; 45. C10 alcohol refining... 46. ​​Reflux tank at the top of the C10 alcohol refining tower; 47. Bottom pump of the C10 alcohol separation tower; 48. Water cooler at the top of the C11 alcohol separation tower; 49. Reflux tank at the top of the C11 alcohol separation tower; 50. Tail gas condenser of the C11 alcohol separation tower; 51. Vacuum pump of the C11 alcohol separation tower; 52. Reflux pump at the top of the C11 alcohol separation tower; 53. Water cooler at the top of the C11 alcohol refining tower; 54. Reflux tank at the top of the C11 alcohol refining tower; 55. Tail gas condenser of the C11 alcohol refining tower; 56. Vacuum pump of the C11 alcohol refining tower; 57. Reflux pump at the top of the C11 alcohol refining tower. Detailed Implementation

[0039] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0040] Unless otherwise specified, the experimental steps or conditions in the examples were performed in accordance with conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0041] Example 1 This embodiment provides a separation and purification system for high-carbon mixed alcohols, including a C5 alcohol pre-cutting tower (1), a C5 alcohol separation tower (2), a C5 alcohol refining tower (3), a C6 alcohol separation tower (4), a C6 alcohol refining tower (5), a C7 alcohol separation tower (6), a C7 alcohol refining tower (7), a C8 alcohol separation tower (8), a C8 alcohol refining tower (9), a C9 alcohol separation tower (10), a C10 alcohol separation tower (11), a C10 alcohol refining tower (12), a C11 alcohol separation tower (13), and a C11 alcohol refining tower (14) connected in ascending order of carbon number for sequential separation.

[0042] The C5 alcohol separation tower (2) is a heat pump distillation tower, integrating a heat pump compressor (16) and a compressor inlet buffer tank (15) for its matching. The tower is also equipped with a C5 alcohol separation tower top reflux tank (17), a C5 alcohol separation tower top reflux pump (18), a C5 alcohol separation tower reflux water cooler (19), a C5 alcohol separation tower bottom reboiler (20), a C5 alcohol separation tower bottom waste heat reboiler (21), and a C5 alcohol separation tower bottom pump (22). The inlet of the heat pump compressor (16) is connected to the C5 alcohol separation tower top vapor phase pipeline, and the outlet is connected to the hot side inlet of the C5 alcohol separation tower bottom waste heat reboiler (21).

[0043] The C5 alcohol refining column (3) is a negative pressure distillation column, equipped with a C5 alcohol refining column top water cooler (23), a C5 alcohol refining column top reflux tank (24), a C5 alcohol refining column tail gas condenser (25), a C5 alcohol refining column vacuum pump (26) and a C5 alcohol refining column top reflux pump (27).

[0044] The C6 alcohol refining column (5) is equipped with a C6 alcohol refining column reboiler (29), a C6 alcohol refining column waste heat reboiler (30), and a C6 alcohol refining column reboiler pump (31). The C5 alcohol pre-cutting column reboiler pump (28) is connected to the reboiler of the C5 alcohol pre-cutting column (1), and the C6 alcohol separation column reboiler pump (32) is connected to the reboiler of the C6 alcohol separation column (4).

[0045] The C7 alcohol separation tower (6) is equipped with a C7 alcohol separation tower bottom pump (33).

[0046] The C8 alcohol separation tower (8) is equipped with a C8 alcohol separation tower top reflux tank (34), a C8 alcohol separation tower top reflux pump (35), and a C8 alcohol separation tower bottom pump (36).

[0047] The C9 alcohol separation tower (10) is a negative pressure distillation tower, equipped with a C9 alcohol separation tower top water cooler (37), a C9 alcohol separation tower top reflux tank (38), a C9 alcohol separation tower tail gas condenser (39), a C9 alcohol separation tower vacuum pump (40), a C9 alcohol separation tower top reflux pump (41), and a C9 alcohol separation tower bottom pump (42).

[0048] The C10 alcohol separation tower (11) is equipped with a C10 alcohol separation tower reboiler (43), a C10 alcohol separation tower waste heat reboiler (44), and a C10 alcohol separation tower reboiler pump (47).

[0049] The C10 alcohol refining column (12) is equipped with a C10 alcohol refining column top reflux tank (45) and a C10 alcohol refining column top reflux pump (46).

[0050] The C11 alcohol separation tower (13) is a negative pressure distillation tower, equipped with a C11 alcohol separation tower top water cooler (48), a C11 alcohol separation tower top reflux tank (49), a C11 alcohol separation tower tail gas condenser (50), a C11 alcohol separation tower vacuum pump (51) and a C11 alcohol separation tower top reflux pump (52).

[0051] The C11 alcohol refining column (14) is a negative pressure distillation column, equipped with a C11 alcohol refining column top water cooler (53), a C11 alcohol refining column top reflux tank (54), a C11 alcohol refining column tail gas condenser (55), a C11 alcohol refining column vacuum pump (56) and a C11 alcohol refining column top reflux pump (57).

[0052] The process flow of this embodiment is as follows: Figure 1 and Figure 2 As shown, the raw material is a product of syngas-to-high carbon alcohols from a factory in Shaanxi. The composition of the raw material high carbon mixed alcohols after pretreatment such as dehydration is shown in Table 1.

[0053] This embodiment also provides a method for separating and purifying high-carbon mixed alcohols, which uses the above-mentioned separation and purification system for high-carbon mixed alcohols, and the specific steps are as follows: The above-mentioned raw material, a mixture of high-carbon alcohols, enters a C5 alcohol pre-cutting column (1) with an operating pressure of 0.08 MPaG, a reflux ratio of 7, and a column top temperature of 157°C. The separated column top stream a is a C5 alcohol containing a small amount of C6 components, and the column bottom stream b is a mixture of C6 and higher-grade alcohols.

[0054] The overhead stream a from the C5 alcohol pre-cutting column (1) enters the C5 alcohol separation column (2), where a small amount of C6 component flows out as the bottom stream d. This stream is mixed with the overhead stream from the C6 alcohol refining column (5) and exits as the product C6 isomeric alcohol. The overhead stream c from the C5 alcohol separation column (2) is C5 alcohol and enters the C5 alcohol refining column (3). The product C5 isomeric alcohol is separated at the top of the column, and the product C5 normal primary alcohol is obtained at the bottom of the column.

[0055] Among them, the C5 alcohol separation tower (2) adopts heat pump distillation technology: C5 alcohol flows out from the top of the tower, enters the heat pump compressor (16) through the compressor inlet buffer tank (15), and is heated by adiabatic compression. It serves as the heat source for the C5 alcohol separation tower bottom waste heat reboiler (21). At the same time, C5 alcohol is condensed by heat exchange and then enters the C5 alcohol separation tower top reflux tank (17). After being pressurized by the C5 alcohol separation tower top reflux pump (18), it is divided into two streams. One stream is cooled by the C5 alcohol separation tower reflux water cooler (19) and returns to the C5 alcohol separation tower (2). The other stream enters the C5 alcohol refining tower (3).

[0056] The C5 alcohol refining tower (3) adopts negative pressure distillation technology, and the operating pressure of the tower is controlled within a suitable range by the C5 alcohol refining tower vacuum pump (26). The C5 isomeric alcohol flows out from the top of the C5 alcohol refining tower (3), and after being cooled by the C5 alcohol refining tower top water cooler (23), it enters the C5 alcohol refining tower top reflux tank (24). The non-condensable gas is condensed and recovered by the C5 alcohol refining tower tail gas condenser (25), and then sent to the flare network by the C5 alcohol refining tower vacuum pump (26). The stream at the bottom (24) of the C5 alcohol refining tower is pressurized by the C5 alcohol refining tower top reflux pump (27) and divided into two streams. One stream returns to the C5 alcohol refining tower (3), and the other stream is discharged from the device as the product C5 isomeric alcohol.

[0057] The bottom stream b of the C5 alcohol pre-cutting column (1) is pumped into the C6 alcohol separation column (4) by the C5 alcohol pre-cutting column bottom pump (28). The C7 and higher components flow out as bottom stream f and enter the C7 alcohol separation column (6) by the C6 alcohol separation column bottom pump (32). The top stream e of the C6 alcohol separation column (4) is C6 alcohol and enters the C6 alcohol refining column (5). The product C6 isomer alcohol is separated at the top of the column and mixed with the bottom stream d of the C5 alcohol separation column (2) before exiting the unit. The bottom of the C6 alcohol refining column (5) yields the product C6 n-primary alcohol.

[0058] The bottom stream f of the C6 alcohol separation column (4) enters the C7 alcohol separation column (6) via the bottom pump (32). The C8 and higher components flow out as bottom stream h and enter the C8 alcohol separation column (8) via the bottom pump (33). The top stream g of the C7 alcohol separation column (6) is C7 alcohol and enters the C7 alcohol purification column (7). The product C7 isomer alcohol is separated at the top of the column, and the product C7 n-primary alcohol is obtained at the bottom of the column.

[0059] The bottom stream h of the C7 alcohol separation column (6) enters the C8 alcohol separation column (8) via the C7 alcohol separation column bottom pump (33). The C9 and higher components flow out as bottom stream j and enter the C9 alcohol separation column (10) via the C8 alcohol separation column bottom pump (36). The top stream i of the C8 alcohol separation column (8) is C8 alcohol and enters the C8 alcohol purification column (9). The product C8 isomer alcohol is separated at the top of the column, and the product C8 n-primary alcohol is obtained at the bottom of the column.

[0060] In this embodiment, C8 alcohol flows out from the top of the C8 alcohol separation tower (8) and serves as the heat source for the reboiler (30) of the C6 alcohol refining tower. At the same time, C8 alcohol undergoes heat exchange and condensation, and then enters the top reflux tank (34) of the C8 alcohol separation tower. After being pressurized by the top reflux pump (35) of the C8 alcohol separation tower, it is divided into two streams, one returning to the C8 alcohol separation tower (8) and the other entering the C8 alcohol refining tower (9).

[0061] The C9 alcohol separation column (10) adopts a partitioned distillation column. The bottom stream j of the C8 alcohol separation column (8) enters the C9 alcohol separation column (10) from the middle of the pre-fractionation side. The product C9 isomer alcohol is separated from the top of the column, and the product C9 n-primary alcohol is collected from the middle section of the main column side. The bottom stream k is C10 and above components, which enter the C10 alcohol separation column (11) through the bottom pump (42) of the C9 alcohol separation column.

[0062] The C9 alcohol separation tower (10) adopts negative pressure distillation technology, and the operating pressure of the tower is controlled at -0.026 MPaG by the C9 alcohol separation tower vacuum pump (40). The C9 isomeric alcohol flows out from the top of the C9 alcohol separation tower (10), and after being cooled by the C9 alcohol separation tower top water cooler (37), it enters the C9 alcohol separation tower top reflux tank (38). The non-condensable gas is condensed and recovered by the C9 alcohol separation tower tail gas condenser (39), and then sent to the flare network by the C9 alcohol separation tower vacuum pump (40). The material at the bottom (38) of the C9 alcohol separation tower top reflux tank is pressurized by the tower top reflux pump (41) and divided into two streams. One stream returns to the C9 alcohol separation tower (10), and the other stream is discharged from the device as the product C9 isomeric alcohol.

[0063] The bottom stream k of the C9 alcohol separation column (10) enters the C10 alcohol separation column (11) via the C9 alcohol separation column bottom pump (42). The C11 and higher components in the column flow out as bottom stream n, which enters the C11 alcohol separation column (13) via the C10 alcohol separation column bottom pump (47). The top stream m of the C10 alcohol separation column (11) is C10 alcohol, which enters the C10 alcohol purification column (12). The product C10 isomer alcohol is separated at the top of the column, and the product C10 normal primary alcohol is obtained at the bottom of the column.

[0064] In this embodiment, the C10 isomeric alcohol flows out from the top of the C10 alcohol refining tower (12) and serves as the heat source for the reboiler (44) of the C10 alcohol separation tower. At the same time, the C10 isomeric alcohol undergoes heat exchange and condensation, and then enters the top reflux tank (45) of the C10 alcohol refining tower. After being pressurized by the top reflux pump (46) of the C10 alcohol refining tower, it is divided into two streams. One stream returns to the C10 alcohol refining tower (12), and the other stream is used as the product C10 isomeric alcohol exit device.

[0065] The bottom stream n of the C10 alcohol separation column (11) enters the C11 alcohol separation column (13) via the bottom pump (47). The C12 and higher components flow out from the bottom of the column to obtain the product C12+ alcohol. The top stream p of the C11 alcohol separation column (13) is C11 alcohol, which enters the C11 alcohol purification column (14). The product C11 isomer alcohol is separated at the top of the column, and the product C11 normal primary alcohol is obtained from the bottom of the column.

[0066] Among them, the C11 alcohol separation tower (13) and the C11 alcohol refining tower (14) adopt negative pressure distillation technology. The operating pressure of the tower is controlled at -0.066MPaG and -0.056MPaG respectively by the vacuum pump installed at the top of each tower.

[0067] C11 alcohol flows out from the top of the C11 alcohol separation tower (13), and after being cooled by the C11 alcohol separation tower top water cooler (48), it enters the C11 alcohol separation tower top reflux tank (49). The non-condensable gas is condensed and recovered by the C11 alcohol separation tower tail gas condenser (50), and then sent to the flare network by the C11 alcohol separation tower vacuum pump (51). The material at the bottom of the C11 alcohol separation tower top reflux tank (49) is pressurized by the C11 alcohol separation tower top reflux pump (52) and divided into two streams. One stream returns to the C11 alcohol separation tower (13), and the other stream enters the C11 alcohol refining tower (14).

[0068] C11 isomer alcohol flows out from the top of the C11 alcohol refining tower (14), and after being cooled by the C11 alcohol refining tower top water cooler (53), it enters the C11 alcohol refining tower top reflux tank (54). The non-condensable gas is condensed and recovered by the C11 alcohol refining tower tail gas condenser (55), and then sent to the flare network by the C11 alcohol refining tower vacuum pump (56). The material at the bottom of the C11 alcohol refining tower top reflux tank (54) is pressurized by the C11 alcohol refining tower top reflux pump (57) and divided into two streams. One stream returns to the C11 alcohol refining tower (14), and the other stream exits the device as the product C11 isomer alcohol.

[0069] In actual operation, those skilled in the art need to select appropriate separation methods and operating conditions based on the functional descriptions of each separation and purification device according to the present invention and the actual raw material composition, in order to achieve the purpose of separation and purification.

[0070] The operating conditions of the main equipment in this embodiment are shown in Table 2. Gas chromatography analysis showed that the recovery rates of each monool separated by the method of this invention were all higher than 95%, and the purity of each monool product is shown in Table 3. The high-quality monools obtained through separation and purification can be used as high-value-added products or as raw materials for the production of downstream fine chemical products. The product recovery rate is calculated as follows: (total mass of the component in the obtained product / total mass of the component in the raw material) × 100%.

[0071] Table 1 Composition of the raw material high-carbon mixed alcohol

[0072] Table 2 Main equipment operating conditions in this embodiment

[0073] Table 3 Purity of each monool product

[0074] Example 2 The difference between this embodiment and Embodiment 1 is that the C5 alcohol refining column (3) adopts different negative pressure operating conditions. Specifically, the top pressure of the column is stably controlled at -0.05 MPaG by adjusting the vacuum pump (26) at the top of the C5 alcohol refining column, while other conditions are the same as in Embodiment 1.

[0075] Example 3 The difference between this embodiment and Embodiment 1 is that the C5 alcohol refining column (3) adopts different negative pressure operating conditions. Specifically, the top pressure of the column is stably controlled at -0.09 MPaG by adjusting the vacuum pump (26) at the top of the C5 alcohol refining column, while other conditions are the same as in Embodiment 1.

[0076] Example 4 The difference between this embodiment and Embodiment 1 is that the C9 alcohol separation column (10) does not use a partitioned distillation column, but instead uses two conventional atmospheric distillation columns (T9-A and T9-B) connected in series to replace its function. The first conventional column is used to separate C9 isomeric alcohols, and the second conventional column is used to separate C9 n-primary alcohols and C10+ heavy components. The specific process is as follows: the bottom stream j of the C8 alcohol separation column (8) enters the first conventional column T9-A, the top of which is the C9 isomeric alcohol product, and the bottom liquid enters the second conventional column T9-B; the top of T9-B is the C9 n-primary alcohol product, and the bottom liquid is the C10+ heavy component. All other conditions are the same as in Embodiment 1.

[0077] Example 5 The difference between this embodiment and Embodiment 1 is that the cross-tower thermal coupling between the overhead stream of the C8 alcohol separation tower (8) and the C6 alcohol refining tower (5) is eliminated. That is, the overhead stream i of the C8 alcohol separation tower (8) is condensed by a newly added circulating water cooler and then enters the top reflux tank (34) of the C8 alcohol separation tower. At the same time, all the heat load of the bottom of the C6 alcohol refining tower (5) comes from externally input steam, which is provided through the reboiler (29) of the C6 alcohol refining tower. All other conditions are the same as in Embodiment 1.

[0078] Example 6 The difference between this embodiment and Embodiment 1 is that the C5 alcohol separation tower (2) does not use heat pump distillation technology, but instead uses conventional distillation operation. Specifically, the modification is as follows: the heat pump compressor (16) and its associated compressor inlet buffer tank (15) are removed; the vapor stream at the top of the C5 alcohol separation tower (2) is completely condensed by an independent circulating water condenser, and the condensate enters the top reflux tank (17) of the C5 alcohol separation tower; the heat load of the tower bottom is entirely provided by the C5 alcohol separation tower bottom reboiler (20), while other conditions are the same as in Embodiment 1.

[0079] Comparative Example 1 This comparative example used the same number of 14 distillation columns as in Example 1 for sequential separation, but all columns were operated at atmospheric pressure (approximately 0.101 MPaG), with conventional steam reboilers used for heating in the reboilers and circulating water used for condensation at the top. Heat pump distillation, negative pressure distillation, partitioned columns, and any form of cross-column thermal coupling technology were not employed. All other conditions were the same as in Example 1.

[0080] Test Example 1 The products obtained in Examples 1-6 and Comparative Example 1 were sampled and analyzed, focusing on: 1. whether monools with each carbon number from C5 to C11 could be obtained; 2. whether alcohols with each carbon number could be separated into primary and isomeric alcohols. Simultaneously, the purity of representative C6 and C9 primary alcohols was determined. Furthermore, under the same raw material (composition shown in Table 1) and the same processing capacity per unit time (3.75 tons / hour), the systems described in Examples 1-6 and Comparative Example 1 were operated stably. Steam consumption (which directly reflects the overall energy consumption of the unit) was measured and recorded for each system during 24 hours of stable operation. The test results are recorded in Table 4.

[0081] Table 4

[0082] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A separation and purification system of high carbon mixed alcohols, characterized in that, The separation and purification system includes a C5 alcohol pre-cutting tower, a C5 alcohol separation tower, a C5 alcohol refining tower, a C6 alcohol separation tower, a C6 alcohol refining tower, a C7 alcohol separation tower, a C7 alcohol refining tower, a C8 alcohol separation tower, a C8 alcohol refining tower, a C9 alcohol separation tower, a C10 alcohol separation tower, a C10 alcohol refining tower, a C11 alcohol separation tower, and a C11 alcohol refining tower, connected in ascending order of carbon number for sequential separation. The C5 alcohol separation tower is a heat pump distillation tower. The gas phase at the top of the tower is compressed and heated by a heat pump compressor and then used as the heat source for the reboiler in the bottom of the tower. The C5 alcohol refining tower, C9 alcohol separation tower, C11 alcohol separation tower, and C11 alcohol refining tower are negative pressure distillation towers.

2. The separation purification system according to claim 1, characterized in that, The C9 alcohol separation column is a partitioned distillation column, which is equipped with vertical partitions to divide the column into a pre-fractionation side and a main column side. The top of the partitioned distillation column is equipped with a C9 isomer alcohol outlet, the middle of the main column side is equipped with a C9 normal primary alcohol side stream outlet, and the bottom of the column is equipped with a C10 and above recombinant alcohol outlet.

3. The separation and purification system according to claim 1 or 2, characterized in that, The top gas phase outlet of the C8 alcohol separation column is connected to the hot side inlet of the reboiler in the bottom of the C6 alcohol refining column. And / or, the top gas phase outlet of the C10 alcohol refining column is connected to the hot-side inlet of the reboiler of the C10 alcohol separation column.

4. The separation and purification system according to claim 1 or 2, characterized in that, The bottoms of the C5 alcohol separation tower, C6 alcohol refining tower and C10 alcohol separation tower are each equipped with two sets of reboilers; one set of reboilers is heated by steam and / or heat transfer oil, and the other set of reboilers is heated by the waste heat of the top steam recovered in the system. And / or, the top of the C5 alcohol refining tower, C9 alcohol separation tower, C11 alcohol separation tower and C11 alcohol refining tower are all equipped with tail gas condensers.

5. The separation and purification system according to claim 1 or 2, characterized in that, The C5 alcohol separation tower is equipped with a compressor inlet buffer tank before the heat pump compressor inlet; the outlet of the heat pump compressor is connected to the hot side inlet of the reboiler in the bottom of the C5 alcohol separation tower; the hot side outlet of the reboiler in the bottom of the C5 alcohol separation tower is connected to the inlet of the reflux tank at the top of the C5 alcohol separation tower; the outlet of the reflux tank at the top of the tower is connected to a reflux pump, and the outlet pipeline of the reflux pump is divided into two paths, one returning to the top of the C5 alcohol separation tower, and the other connecting to the feed inlet of the C5 alcohol refining tower; And / or, the top of the C5 alcohol refining column is connected to a vacuum pump via a pipeline; the top of the C5 alcohol refining column is also connected in sequence to a water cooler, a C5 alcohol refining column top reflux tank and a tail gas condenser via a top discharge pipeline.

6. A method for separating and purifying high-carbon mixed alcohols, characterized in that, The high-carbon mixed alcohol separation and purification system as described in any one of claims 1 to 5 is used to separate and purify mixed alcohol raw materials containing C5 to C12 fatty alcohols.

7. The separation and purification method according to claim 6, characterized in that, Includes the following steps: (1) A mixed alcohol feedstock containing C5~C12 fatty alcohols is fed into a C5 alcohol pre-cutting column to separate the overhead stream a and the bottom stream b; wherein, the overhead stream a contains C5 alcohol and a small amount of C6 alcohol, and the bottom stream b contains C6 alcohol and the above alcohol components. (2) The overhead stream a is fed into a C5 alcohol separation column for separation to obtain overhead stream c and bottom stream d; wherein, overhead stream c is C5 alcohol and bottom stream d is a small amount of C6 alcohol. The overhead stream c is fed into a C5 alcohol purification column for separation. C5 isomer alcohol is separated at the top of the column, and C5 normal primary alcohol is obtained at the bottom of the column. (3) The bottom stream b is fed into a C6 alcohol separation column for separation to obtain the top stream e and the bottom stream f; wherein, the top stream e is C6 alcohol and the bottom stream f contains C7 alcohol and above alcohol components. The overhead stream e is fed into a C6 alcohol purification column for separation. C6 isomer alcohol is separated at the top of the column, and C6 normal primary alcohol is obtained at the bottom of the column. The C6 isomer alcohol is mixed with the bottom stream d and discharged. (4) The bottom stream f is fed into a C7 alcohol separation column for separation to obtain the top stream g and the bottom stream h; wherein the top stream g is C7 alcohol and the bottom stream h contains C8 alcohol and above alcohol components. The overhead stream g was fed into a C7 alcohol purification column for separation. C7 isomer alcohols were separated at the top of the column, and C7 normal primary alcohols were obtained at the bottom of the column. (5) The bottom stream h is fed into a C8 alcohol separation column for separation to obtain the top stream i and the bottom stream j; wherein, the top stream i is C8 alcohol and the bottom stream j contains C8 alcohol and above alcohol components. The overhead stream i is fed into a C8 alcohol purification column for separation. C8 isomer alcohols are separated at the top of the column, and C8 normal primary alcohols are obtained at the bottom of the column. (6) The bottom stream j is fed into a C9 alcohol separation column for separation to obtain C9 isomer alcohol, C9 normal primary alcohol and bottom stream k; wherein, bottom stream k contains C10 alcohol and above alcohol components. (7) The bottom stream k is fed into a C10 alcohol separation column for separation to obtain the top stream m and the bottom stream n; wherein, the top stream m is C10 alcohol and the bottom stream n contains C11 alcohol and above alcohol components. The overhead stream m is fed into a C10 alcohol purification column for separation. C10 isomer alcohols are separated at the top of the column, and C10 normal primary alcohols are obtained at the bottom of the column. (8) The bottom stream n is fed into a C11 alcohol separation column for separation to obtain the top stream p and the bottom stream q; wherein, the top stream p is C11 alcohol, and the bottom stream q contains C12 alcohol and above alcohol components; the bottom stream q is produced as a heavy component of C12 and above. The overhead stream p is fed into a C11 alcohol purification column for separation. C11 isomer alcohols are separated at the top of the column, and C11 normal primary alcohols are obtained at the bottom of the column.

8. The separation and purification method according to claim 7, characterized in that, In step (2), when the C5 alcohol separation tower is separating, the gas phase at the top of the tower is compressed by a heat pump compressor and used as the heat source for the reboiler of the tower. And / or, in step (2), the separation is carried out in the C5 alcohol purification column under vacuum conditions; And / or, in step (6), the separation is carried out in the C9 alcohol separation tower under vacuum conditions; And / or, in step (8), when separation is carried out in the C11 alcohol separation tower and / or the C11 alcohol refining tower, the operation is carried out under vacuum conditions.

9. The separation and purification method according to claim 7 or 8, characterized in that, In step (6), the separation of the C9 alcohol is carried out in a distillation column next to the wall. The C9 isomer alcohol is drawn from the top of the column, the C9 normal primary alcohol is drawn from the side stream of the main column, and the bottom stream k is drawn from the bottom of the column.

10. The separation and purification method according to claim 7 or 8, characterized in that, In step (5), the heat of condensation of the top stream i of the C8 alcohol separation column is used as the heat source for the reboiler of the C6 alcohol refining column. And / or, in step (7), the condensation heat of the top stream of the C10 alcohol refining column is used as the heat source for the reboiler of the C10 alcohol separation column.

Images