MIBK rectification system and rectification method for removing light components

Abstract

The application discloses a kind of MIBK removes light component's rectification system and rectification method, belong to chemical rectification technical field.Rectification system includes rectification tower, rectification tower includes the tower body of cylindrical barrel structure, tower body is equipped with vertical partition, and is divided into first pre-fractionation section, azeotrope rectification section, stripping section, second pre-fractionation section, acetone rectification section in rectification tower.Using above rectification equipment, organic mixed solution containing 2-MPA, acetone and other light components from MIBK synthesis system can be rectified, extracted, separated.Extraction section obtains target product 2-MPA boundary area;Rectification tower acetone rectification section obtains target product two acetone as raw material and returns MIBK synthesis system directly for use;Rectification tower stripping section obtains target product three MIBK solution boundary area rectification, separates MIBK.Using the rectification system of the application can reduce the number of equipment, simplify process flow, reduce device investment, reduce raw materials and energy consumption in production, reduce production cost, reduce carbon emission of production device.

Description

Technical Field

[0001] This invention relates to the field of chemical distillation technology, specifically to a distillation system and method for removing light components using MIBK. Background Technology

[0002] MIBK, chemically known as methyl isobutyl ketone, also called 4-methyl-2-pentanone, is an organic compound with the chemical formula C6H. 12 O is mainly used as a solvent for paints, nitrocellulose, certain fiber ethers, camphor, oils, and natural and synthetic rubbers.

[0003] In the MIBK synthesis system, every ton of MIBK product synthesized generates approximately 2824 kg of light components containing the raw material acetone and the byproduct 2-MPA, including approximately 2802 kg of acetone and approximately 22 kg of 2-MPA. These organic light components require distillation, extraction, and distillation to recover the useful components. In existing production, a two-step distillation process is typically used. Step 1: The azeotrope is purified and recovered through an azeotropic distillation separation and recovery system. The azeotrope is then sent to an extraction system to recover the first target product—2-MPA. The acetone aqueous solution produced by the extraction system is mixed with the bottom liquid produced by the azeotropic distillation separation and recovery system. Step 2: The bottom liquid from Step 1 is sent to an acetone distillation separation and recovery system to recover the second target product—acetone. The bottom liquid serves as the third target product—(the MIBK solution with light components removed). The light components such as 2-MPA and acetone mentioned above are separated and recovered through two sets of distillation separation and recovery systems. Distillation separation is the most mature and widely used separation technology in chemical production. However, the distillation process consumes a lot of energy. More than 50% of the energy consumption in chemical production is used for separation, and distillation separation energy consumption accounts for 95% of that.

[0004] Therefore, it is necessary to improve the existing distillation equipment for separating and recovering light components such as 2-MPA and acetone. There is an urgent need to provide a distillation equipment for removing light components from MIBK that has a short process, small footprint, low investment, and low energy consumption. Summary of the Invention

[0005] The purpose of this invention is to provide a distillation system for removing light components from MIBK, which features a short process, small footprint, low investment, and low energy consumption. This system is used for distillation, extraction, and separation of organic mixtures containing light components such as 2-MPA and acetone from a MIBK synthesis system. This invention also provides a distillation method for removing light components from MIBK.

[0006] The MIBK distillation system for removing light components of the present invention adopts the following technical solution: A MIBK distillation system for removing light components includes a distillation column, the distillation column including a cylindrical column body, a vertically structured partition plate inside the column body, the partition plate being vertically arranged and fixedly connected at its upper end to the top of the column body, the top of the column body having an azeotrope outlet A and an acetone outlet B, the upper side of the column body having an azeotrope reflux port C and an acetone reflux port D, the middle side of the column body having a raw material inlet E and an acetone aqueous solution inlet F, the lower part of the column body having a reflux port G and a bottom liquid sidewall outlet H, and the bottom of the column body having a bottom liquid outlet J. The azeotrope outlet A, the azeotrope reflux port C, and the raw material inlet E are located on the same side of the partition plate, the acetone outlet B, the acetone reflux port D, and the acetone aqueous solution inlet F are located on the other side of the partition plate, and the reflux port G, the bottom liquid outlet H, and the bottom liquid outlet J are located below the partition plate; Inside the column, the upper part of one side of the partition plate is an azeotropic rectification section, and the lower part is a first pre-fractionation section. The upper part of the other side of the partition plate is an acetone rectification section, and the lower part is a second pre-fractionation section. The stripping section is located below the partition plate inside the column. The upper part of the first pre-fractionation section is a first pre-fractionation section rectification layer, and the lower part is a first pre-fractionation section stripping layer. The bottom of the first pre-fractionation section stripping layer is not lower than the bottom of the partition plate. The raw material inlet E is located between the first pre-fractionation section rectification layer and the first pre-fractionation section stripping layer. The column is provided with a raw material feed pipe connected to the raw material inlet E, which is located in the gap between the first pre-fractionation section rectification layer and the first pre-fractionation section stripping layer. The azeotropic rectification section is located between the first pre-fractionation section rectification layer and the azeotropic outlet A at the top of the column. The azeotropic rectification section is provided with an azeotropic rectification section rectification layer, which is spaced apart from the first pre-fractionation section rectification layer. The stripping section is provided with a stripping layer, and there is a gap between the stripping layer and the partition plate. A stripping liquid distributor is horizontally installed in the gap. The upper part of the second pre-fractionation section is the rectification layer, and the lower part is the stripping layer. The bottom of the stripping layer is not lower than the bottom of the partition plate. The acetone aqueous solution inlet F is located between the rectification layer and the stripping layer. The column body is provided with an acetone aqueous solution feed pipe connected to the acetone aqueous solution inlet F. The acetone aqueous solution feed pipe is located in the gap between the rectification layer and the stripping layer. The acetone rectification section is located between the second pre-fractionation section rectification layer and the acetone outlet B at the top of the distillation column. The acetone rectification section is provided with an acetone rectification layer, and there is a gap between the acetone rectification layer and the second pre-fractionation section rectification layer. The distillation column is equipped with an azeotropic product collection tank, an extraction column, a phase separator, and an acetone aqueous solution collection tank. A feed preheater connected to the feed inlet E is also provided outside the distillation column. The azeotropic product collection tank is connected via a pipeline between the azeotropic outlet A of the extraction column and the distillation column. An azeotropic product collection cooler is connected to the pipeline between the azeotropic outlet A and the azeotropic product collection tank. The phase separator is connected between the bottom of the extraction column and the acetone aqueous solution collection tank. An extraction column feed pump is installed on the pipeline between the extraction column and the azeotropic product collection tank. The bottom outlet of the acetone aqueous solution collection tank is connected to the acetone aqueous solution inlet F via a pipeline. An acetone aqueous solution feed pump and an acetone aqueous solution heater are installed on the pipeline between the acetone aqueous solution collection tank and the acetone aqueous solution inlet F.

[0007] A raw material inlet liquid distributor is horizontally installed below the raw material feed pipe; there is a gap between the rectification layer of the azeotropic rectification section and the rectification layer of the first pre-fractionation section, and a first liquid distributor is horizontally installed in the gap; a second liquid distributor is horizontally installed below the acetone aqueous solution feed pipe; there is a gap between the rectification layer of the acetone rectification section and the rectification layer of the second pre-fractionation section, and a third liquid distributor is horizontally installed in the gap.

[0008] There is a gap between the rectification layer of the azeotropic distillation section and the azeotropic outlet A. An azeotropic reflux port C is provided on the side wall of the gap. A first row of tubular liquid distributors is horizontally installed at the azeotropic reflux port C. The azeotrope is refluxed sequentially through the azeotropic outlet A and the azeotropic reflux port C.

[0009] An azeotrope condenser, an azeotrope reflux tank, and an azeotrope reflux pump are sequentially connected between the azeotrope outlet A and the azeotrope reflux port C via a pipeline.

[0010] There is a gap between the acetone rectification section and the acetone outlet B. An acetone reflux port D is provided on the side wall of the gap. A second row of tubular liquid distributors is horizontally installed at the acetone reflux port D. Acetone is refluxed sequentially through the acetone outlet B and the acetone reflux port D.

[0011] An acetone condenser, an acetone reflux tank, and an acetone reflux pump are sequentially connected between the acetone outlet B and the acetone reflux port D via a pipeline.

[0012] There is a gap between the stripping layer of the stripping section and the bottom liquid sidewall outlet H. A reflux port G is provided on the sidewall of the gap. An air inlet distributor is horizontally installed at the reflux port G. The bottom liquid vapor is refluxed sequentially through the bottom liquid sidewall outlet H and the reflux port G.

[0013] A reboiler is connected between the liquid sidewall outlet H and the reflux port G of the tower bottom via a pipe.

[0014] The ratio of the horizontal cross-sectional area of ​​the azeotropic distillation section to the acetone distillation section, the first pre-fractionation section to the second pre-fractionation section, and the first pre-fractionation section stripping section to the second pre-fractionation section stripping section is 1:10 to 10:1.

[0015] The rectification layers of the azeotropic distillation section, the acetone distillation section, the first pre-fractionation section, the second pre-fractionation section, the first pre-fractionation section stripping layer, and the second pre-fractionation section stripping layer are all packed layers with a height of 2 to 12 meters; the stripping layer of the stripping section is also a packed layer with a height of 2 to 12 meters.

[0016] The method for removing light components using the above-mentioned distillation system for MIBK includes the following steps: (1) First pre-fractionation section: The raw material from the MIBK synthesis system, namely the organic mixture, is preheated by the raw material preheater and then enters the first pre-fractionation section of the distillation column from the raw material inlet E for pre-fractionation. After pre-fractionation, the organic mixture is initially fractionated. The mixture of MIBK, heavy components and water flows downward and is first stripped through the stripping layer of the first pre-fractionation section before going to the stripping section. The azeotropic gas of 2-MPA and acetone flows upward and is first refined through the rectification layer of the first pre-fractionation section before going to the azeotropic rectification section. (2) Azeotropic distillation section: The azeotropic gas of 2-MPA and acetone from the first pre-fractionation section is distilled in the azeotropic distillation section. It undergoes heat and mass transfer with the azeotropic solution refluxed from the azeotropic reflux port C on the upper side of the distillation column. The azeotropic solution flows downward into the first pre-fractionation section. The azeotropic gas after distillation exits the distillation column from the azeotropic outlet A at the top of the distillation column and is condensed into liquid by the azeotropic condenser before entering the azeotropic reflux tank. A portion of the azeotropic solution in the azeotropic reflux tank is used as reflux liquid and exits from the reflux liquid outlet B of the azeotropic reflux tank. It enters the azeotropic distillation section of the distillation column from the azeotropic reflux port C on the upper side of the distillation column through the azeotropic reflux pump. The other portion of the azeotropic solution in the azeotropic reflux tank is used as extract and goes to the azeotropic extraction section from the extract outlet C of the azeotropic reflux tank. The ratio of the two portions of the azeotropic solution is 378:1. (3) Azeotropic Extraction Section: The azeotropic solution of 2-MPA and acetone from the azeotropic distillation section is first cooled by the azeotropic extractor cooler and then enters the azeotropic extractor tank. The azeotropic solution in the azeotropic extractor tank is fed into the extraction tower from the upper inlet of the extraction tower by the extraction tower feed pump. Water from the boundary area enters the extraction tower from the upper inlet A of the extraction tower. In the extraction tower, acetone in the azeotropic solution enters the water and forms an acetone aqueous solution. 2-MPA is insoluble in water. After extraction, the mixture of acetone aqueous solution and 2-MPA solution exits the extraction tower from the lower outlet C and enters the phase separator from the middle inlet A of the phase separator. In the phase separator, the acetone aqueous solution and 2-MPA solution are separated. The acetone aqueous solution enters the lower layer of the phase separator and goes to the second pre-fractionation section from the bottom outlet C of the phase separator. The 2-MPA solution enters the upper layer of the phase separator and goes to the boundary area as the target product from the upper outlet B of the phase separator. (4) Second pre-fractionation section: The acetone aqueous solution from the azeotropic extraction section enters the acetone aqueous solution collection tank. The acetone aqueous solution is fed into the acetone aqueous solution heater by the acetone aqueous solution feed pump and then enters the second pre-fractionation section of the distillation column through the acetone aqueous solution inlet F for pre-fractionation. After pre-fractionation, the acetone aqueous solution is initially fractionated. The aqueous solution flows downward and is first stripped through the stripping layer of the second pre-fractionation section before going to the stripping section. The acetone gas flows upward and is first rectified through the rectification layer of the second pre-fractionation section before going to the acetone rectification section. (5) Acetone distillation section: Acetone gas from the second pre-fractionation section is distilled in the acetone distillation section and undergoes heat and mass transfer with the acetone solution refluxed from the acetone reflux port D on the upper side of the distillation column. The acetone solution flows downward into the second pre-fractionation section. The distilled acetone gas exits the distillation column from the acetone outlet B at the top of the distillation column and is condensed into liquid by the acetone condenser before entering the acetone reflux tank. A portion of the acetone solution in the acetone reflux tank is used as reflux liquid and exits from the reflux liquid outlet of the acetone reflux tank. It then enters the acetone distillation section of the distillation column from the acetone reflux port D on the upper side of the distillation column through the acetone reflux pump. The other portion of the acetone solution in the acetone reflux tank is used as target product 2 and is sent from the acetone outlet of the acetone reflux tank to the MIBK synthesis system for reuse. The ratio of the two portions of acetone solution is 6.3:1. (6) Stripping section: The mixed liquid of MIBK, heavy components and water from the first pre-fractionation section and the aqueous solution from the second pre-fractionation section are stripped in the stripping section. Heat and mass transfer are carried out with the gas phase refluxed from the bottom reflux port G of the distillation column. The stripped acetone gas flows upward into the second pre-fractionation section, and the mixed liquid of MIBK, heavy components and water flows downward. Part of the mixed liquid goes to the reboiler from the bottom liquid outlet H of the distillation column. In the reboiler, the mixed liquid is heated and the acetone in the mixed liquid is heated and evaporated into gas as gas phase and enters the stripping section from the bottom reflux port G of the distillation column. The other part of the mixed liquid goes to the bottom liquid outlet of the distillation column as target product three, namely MIBK solution, to the MIBK distillation system in the boundary area to distill MIBK product.

[0017] The beneficial effects of this invention are as follows: In the MIBK synthesis system, approximately 2824 kg of light components containing the raw material acetone and the byproduct 2-MPA are generated for every ton of MIBK synthesized, including approximately 2802 kg of acetone and approximately 22 kg of 2-MPA. This invention provides a distillation system and method for removing light components from MIBK. Using this distillation system and method, acetone and 2-MPA can be effectively recovered. For every ton of light components removed, approximately 992.2 kg of acetone and approximately 7.8 kg of 2-MPA can be recovered.

[0018] This invention employs a partitioned plate distillation column instead of an azeotropic and acetone distillation column, combining the two into one and eliminating the need for a reboiler, thus saving approximately 25% on equipment investment. Since azeotropes and acetone have similar boiling points, dividing the distillation column into azeotropic and acetone sections facilitates the distillation of both light components. Acetone is present in both the azeotropic and acetone sections, ensuring that the composition of the feed entering the partitioned plate distillation column and the acetone aqueous solution entering the acetone aqueous solution inlet matches well with the composition of the liquid distributors in the first and second pre-fractionation sections. This reduces the mixing effect at the liquid distributor, minimizing the mixing impact caused by differences in feed and liquid distributor compositions, meeting the requirements of an optimal liquid distributor, and improving thermodynamic efficiency. Because heat is repeatedly recycled within the same column, energy consumption is also saved, by approximately 25%.

[0019] Using the above distillation system and method, target product one—2-MPA, target product two—acetone, and target product three—MIBK solution are obtained. This is a safe, environmentally friendly distillation system and method for removing light components from MIBK with high target product yield and low energy consumption. The present invention aims to save energy and reduce consumption, reduce carbon emissions from production equipment, and protect the environment.

[0020] This invention enables the distillation, extraction, and separation of organic mixtures containing light components such as 2-MPA and acetone from a MIBK synthesis system. The phase separator recovers target product one—2-MPA from the boundary zone; the acetone reflux tank recovers target product two—acetone for reuse in the MIBK synthesis system; and the distillation column recovers target product three—(light component removed) MIBK solution from the boundary zone—the distilled MIBK product from the MIBK distillation system.

[0021] Unlike existing distillation columns, this invention features a vertical partition plate within the distillation column. The partition plate has two feed inlets on each side, two gas outlets at the top, and two liquid reflux inlets at the top. The distillation column has two rectification sections. The azeotropic distillation section recovers the azeotrope, which is then used in the extraction section to recover target product one—2-MPA. The acetone distillation section recovers target product two—acetone, which is directly reused in the MIBK synthesis system as a raw material. The stripping section recovers target product three—a MIBK solution (with light components removed)—which is then used in the boundary MIBK distillation system to refine MIBK products.

[0022] Using the technical solution of this invention, only one distillation system is needed to recover the target product. It is a distillation system and method for removing light components from MIBK with a short process, small footprint, low investment, and low energy consumption. This invention has the advantages of energy saving and consumption reduction, reduced investment in production equipment, reduced carbon emissions, and environmental protection. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process flow of a MIBK distillation system for removing light components according to an embodiment of the present invention. Figure 2 for Figure 1 A schematic diagram of a distillation column; Figure 3 for Figure 1 Diagram of the working sections of a distillation column; Figure 4 This is a performance evaluation result table for a 10,000-ton / year MIBK light component removal unit.

[0024] Among them, 1. Raw material preheater; 2. Distillation column; 2-1. Raw material feed pipe; 2-2. Raw material inlet liquid distributor; 2-3. First pre-fractionation section rectification layer; 2-4. First pre-fractionation section stripping layer; 2-5. Azeotropic rectification section rectification layer; 2-6. First liquid distributor; 2-7. First pipe-type liquid distributor; 2-8. Stripping section stripping layer; 2-9. Stripping section liquid distributor; 2-10. Inlet distributor; 2-11. Acetone aqueous solution feed pipe; 2-12. Second liquid distributor; 2-13. Second pre-fractionation section rectification layer; 2-14. Second pre-fractionation section rectification layer; 2-15. Fractionating section stripping layer; 2-16. Acetone rectification section rectification layer; 2-17. Third liquid distributor; 2-18. Second tubular liquid distributor; 3. Divider plate; 4. Azeotropic condenser; 5. Azeotropic reflux tank; 6. Azeotropic reflux pump; 7. Azeotropic product cooler; 8. Azeotropic product tank; 9. Extraction column feed pump; 10. Extraction column; 11. Phase separator; 12. Acetone aqueous solution product tank; 13. Acetone aqueous solution feed pump; 14. Acetone aqueous solution heater; 15. Acetone condenser; 16. Acetone reflux tank; 17. Acetone reflux pump; 18. Reboiler. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention. The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0027] An embodiment of the MIBK distillation system for removing light components according to the present invention is as follows: Figure 1As shown, it includes a distillation column, and a feed preheater 1, an azeotropic condenser 4, an azeotropic reflux tank 5, an azeotropic reflux pump 6, an azeotropic product cooler 7, an azeotropic product tank 8, an extraction column feed pump 9, an extraction column 10, a phase separator 11, an acetone aqueous solution product tank 12, an acetone aqueous solution feed pump 13, an acetone aqueous solution heater 14, an acetone condenser 15, an acetone reflux tank 16, an acetone reflux pump 17, and a reboiler 18, all located outside the distillation column 2.

[0028] The structure of the distillation column is as follows: Figure 2 , 3 As shown, this distillation column can distill, extract, and separate organic mixtures containing light components such as 2-MPA and acetone from the MIBK synthesis system. The distillation column includes a cylindrical body with a vertical partition plate 3 extending to the top of the column. The top of the distillation column 2 has an azeotrope outlet A and an acetone outlet B. The upper side of the distillation column 2 has an azeotrope reflux port C and an acetone reflux port D. The middle side of the distillation column 2 has a feed inlet E and an acetone aqueous solution inlet F. The lower part of the distillation column 2 has a reflux port G and a bottom liquid outlet H. The bottom of the distillation column 2 has a bottom liquid outlet J. The azeotrope outlet A, azeotrope reflux port C, and feed inlet E are located on the same side of the partition plate 3. The acetone outlet B, acetone reflux port D, and acetone aqueous solution inlet F are located on the other side of the partition plate 3. The reflux port G, bottom liquid outlet H, and bottom liquid outlet J are located below the partition plate 3.

[0029] like Figure 2-3 As shown, the upper part of the distillation column 2, near the azeotrope outlet A, azeotrope reflux port C, and feed inlet E on one side of the partition plate 3, is the azeotrope rectification section, and the lower part is the first pre-fractionation section. The upper part of the first pre-fractionation section is the first pre-fractionation section rectification layer 2-3, and the lower part is the first pre-fractionation section stripping layer 2-4. The bottom of the first pre-fractionation section stripping layer 2-4 is not lower than the bottom height of the partition plate 3. There is a gap between the first pre-fractionation section rectification layer 2-3 and the first pre-fractionation section stripping layer 2-4. A feed pipe 2-1 is horizontally installed at the feed inlet E on the side wall of the gap, and a feed inlet liquid distributor 2-2 is horizontally installed below the feed pipe 2-1. The area from the first pre-fractionation section rectification layer 2-3 to the azeotropic outlet A at the top of distillation column 2 constitutes the azeotropic rectification section. The middle part of this section is the azeotropic rectification layer 2-5. A gap exists between the azeotropic rectification layer 2-5 and the first pre-fractionation section rectification layer 2-3, within which a first liquid distributor 2-6 is horizontally installed. A gap also exists between the azeotropic rectification layer 2-5 and the azeotropic outlet A. An azeotropic reflux port C is located on the sidewall of this gap. A first tubular liquid distributor 2-7 is horizontally installed at the azeotropic reflux port C, allowing the azeotrope to reflux sequentially through the azeotropic outlet A and the azeotropic reflux port C.

[0030] like Figure 2-3As shown, the middle part of the stripping section is the stripping layer 2-8. There is a gap between the stripping layer 2-8 and the partition plate 3. A stripping liquid distributor 2-9 is horizontally installed in the gap. There is a gap between the stripping layer 2-8 and the bottom liquid outlet H. A reflux port G is provided on the side wall of the gap. An inlet distributor 2-10 is horizontally installed at the reflux port G. The bottom vapor is refluxed sequentially through the bottom liquid outlet H and the reflux port G.

[0031] like Figure 2-3 As shown, the upper part of one side of the distillation column 2, which has acetone outlet B, acetone reflux port D, and acetone aqueous solution inlet F, is the acetone rectification section, and the lower part is the second pre-fractionation section. The upper part of the second pre-fractionation section is the second pre-fractionation section rectification layer 2-13, and the lower part is the second pre-fractionation section stripping layer 2-14. The bottom of the second pre-fractionation section stripping layer 2-14 is not lower than the bottom height of the partition plate 3. There is a gap between the second pre-fractionation section rectification layer 2-13 and the second pre-fractionation section stripping layer 2-14. An acetone aqueous solution feed pipe 2-11 is horizontally installed at the acetone aqueous solution inlet F on the sidewall of the gap. A second liquid distributor 2-12 is horizontally installed below the acetone aqueous solution feed pipe 2-11. The area from the second pre-fractionation section rectification layer 2-13 to the acetone outlet B at the top of distillation column 2 constitutes the acetone rectification section. The middle section of the acetone rectification section is the acetone rectification layer 2-15. A gap exists between the acetone rectification layer 2-15 and the second pre-fractionation section rectification layer 2-13, and a third liquid distributor 2-16 is horizontally installed in this gap. A gap exists between the acetone rectification layer 2-15 and the acetone outlet B. An acetone reflux port D is located on the sidewall of this gap. A second tubular liquid distributor 2-17 is horizontally installed at the acetone reflux port D, allowing acetone to reflux sequentially through the acetone outlet B and the acetone reflux port D.

[0032] like Figure 2 As shown, the ratio of the horizontal cross-sectional areas of the azeotropic rectification section rectification layer 2-5 to the acetone rectification section rectification layer 2-15, the first pre-fractionation section rectification layer 2-3 to the second pre-fractionation section rectification layer 2-13, and the first pre-fractionation section stripping layer 2-4 to the second pre-fractionation section stripping layer 2-14 is 64:100. The azeotropic rectification section rectification layer 2-5, the first pre-fractionation section rectification layer 2-3, the first pre-fractionation section stripping layer 2-4, and the acetone rectification section rectification layer 2-15 are all packed layers with a height of 3 meters. The second pre-fractionation section rectification layer 2-13 and the second pre-fractionation section stripping layer 2-14 are both packed layers with a height of 4 meters. The stripping section stripping layer 2-8 is a packed layer with a height of 3 meters.

[0033] The feedstock from the MIBK synthesis system—an organic mixture—is connected via a feedstock preheater 1 to the feedstock inlet E on the side of the middle section of distillation column 2. The azeotropic outlet A at the top of distillation column 2 is sequentially connected to the azeotropic condenser 4, the azeotropic reflux tank 5, the azeotropic product cooler 7, the azeotropic product tank 8, the extraction column feed pump 9, and the upper inlet B of extraction column 10. The lower outlet C of extraction column 10 is connected to the middle inlet A of phase separator 11, and the upper outlet B of phase separator 11 is connected to the target product—2-MPA—in the decontamination zone.

[0034] The bottom outlet C of the phase separator 11 is connected in sequence to the acetone aqueous solution collection tank 12, the acetone aqueous solution feed pump 13, the acetone aqueous solution heater 14, and the acetone aqueous solution inlet F on the side of the middle section of the distillation column 2. The top acetone outlet B of the distillation column 2 is connected to the top inlet A of the acetone reflux tank 16 through the acetone condenser 15. The lower outlet C of the acetone reflux tank 16 is connected to the pipeline of the second target product for reuse—acetone.

[0035] The bottom outlet J of distillation column 2 is connected to the pipeline of the target product 3—MIBK solution in the delimited area.

[0036] The lower outlet B of the azeotropic reflux tank 5 is connected to the upper azeotropic reflux port C of the distillation column 2 via the azeotropic reflux pump 6; the lower outlet B of the acetone reflux tank 16 is connected to the upper acetone reflux port D of the distillation column 2 via the acetone reflux pump 17; the lower bottom liquid outlet H of the distillation column 2 is connected to the bottom inlet A of the reboiler 18, and the top outlet B of the reboiler 18 is connected to the lower reflux port G of the distillation column 2.

[0037] A water pipe from the boundary area is connected to the upper inlet A of extraction tower 2. A specific embodiment of the method for removing light components from MIBK using the above-described distillation system includes the following steps: (1) First Pre-fractionation Section: The raw material from the MIBK synthesis system—an organic mixture (temperature 45℃, containing 0.55% 2-MPA, 69.06% acetone, 24.65% MIBK, with the remainder being heavy components and water)—is preheated (temperature 64℃) by the raw material preheater 1 and then enters the first pre-fractionation section of distillation column 2 through the raw material inlet E for pre-fractionation. After pre-fractionation, the organic mixture undergoes preliminary fractionation. The mixture of MIBK, heavy components, and water flows downward and is first stripped through the stripping layer 2-4 of the first pre-fractionation section before proceeding to the stripping section; the azeotropic gas of 2-MPA and acetone flows upward and is first rectified through the rectification layer 2-3 of the first pre-fractionation section before proceeding to the azeotropic rectification section. (2) Azeotropic distillation section: The azeotropic gas of 2-MPA and acetone from the first pre-fractionation section distillation layer 2-3 is distilled in the azeotropic distillation section distillation layer 2-5. It undergoes heat and mass transfer with the azeotropic solution refluxed from the azeotropic reflux port C on the upper side of the distillation column 2. The azeotropic solution flows downwards into the first pre-fractionation section. The distilled azeotropic gas (temperature 55℃, 25% 2-MPA mass concentration, 75% acetone mass concentration) exits the distillation column 2 from the azeotropic outlet A at the top of the column and passes through the azeotropic reflux port C. The azeotropic solution is condensed into liquid (temperature 55℃) in azeotropic condenser 4 and then enters azeotropic reflux tank 5. A portion of the azeotropic solution in azeotropic reflux tank 5 is discharged as reflux liquid from reflux liquid outlet B of azeotropic reflux tank 5 and enters the azeotropic rectification section of distillation column 2 from the azeotropic reflux port C on the upper side of distillation column 2 through azeotropic reflux pump 6. The other portion of the azeotropic solution in azeotropic reflux tank 5 is discharged as product from product outlet C of azeotropic reflux tank 5 to azeotropic extraction section. The ratio of the two portions of azeotropic solution is 378:1. (3) Azeotropic extraction section: The azeotropic solution of 2-MPA and acetone from the azeotropic distillation section is first cooled by the azeotropic extractor cooler 7 (temperature 45℃), and then enters the azeotropic extractor tank 8. The azeotropic solution in the azeotropic extractor tank 8 is sent to the extraction tower 10 from the upper inlet B through the extraction tower feed pump 9. Water from the boundary area enters the extraction tower 10 from the upper inlet A. In the extraction tower 10, the acetone in the azeotropic solution enters the water and forms an acetone aqueous solution with the water. 2-MPA is insoluble in water. After extraction, the mixture of acetone aqueous solution and 2-MPA solution exits from the lower outlet C of extraction tower 10 and enters the middle inlet A of phase separator 11. In phase separator 11, the acetone aqueous solution and 2-MPA solution undergo phase separation. The acetone aqueous solution (containing 19.95% acetone by mass, with the remainder being water) enters the lower layer of phase separator 11 and goes to the second pre-fractionation section from the bottom outlet C of phase separator 11. The 2-MPA solution (containing 99% 2-MPA by mass) enters the upper layer of phase separator 11 and goes to the boundary area as the target product. (4) Second Pre-fractionation Section: The acetone aqueous solution from the azeotropic extraction section enters the acetone aqueous solution collection tank 12. The acetone aqueous solution is then fed into the acetone aqueous solution heater 14 via the acetone aqueous solution feed pump 13 for heating (temperature 70℃). After heating, the acetone aqueous solution enters the second pre-fractionation section of distillation column 2 through the acetone aqueous solution inlet F for pre-fractionation. After pre-fractionation, the acetone aqueous solution undergoes preliminary fractionation. The aqueous solution flows downwards, first passing through the stripping layer 2-14 of the second pre-fractionation section for stripping, and then to the stripping section; the acetone gas flows upwards, first passing through the rectification layer 2-13 of the second pre-fractionation section for rectification, and then to the acetone rectification section. (5) Acetone Distillation Section: Acetone gas from the second pre-fractionation section, in rectification layer 2-13, undergoes rectification in rectification layer 2-15 of the acetone rectification section. It exchanges heat and mass with the acetone solution refluxed from the acetone reflux port D on the upper side of the distillation column 2. The acetone solution flows downwards into the second pre-fractionation section. The distilled acetone gas (temperature 56.5℃, acetone mass concentration 99.5%) exits the distillation column 2 from the acetone outlet B at the top of the column and is condensed into a liquid (temperature 56.5℃) by the acetone condenser 15. The solution is then fed into acetone reflux tank 16. A portion of the acetone solution in acetone reflux tank 16 is discharged as reflux liquid from reflux liquid outlet B of acetone reflux tank 16 and enters the acetone rectification section of distillation column 2 from the acetone reflux port D on the upper side of distillation column 2 via acetone reflux pump 17. The other portion of the acetone solution in acetone reflux tank 16 (containing acetone mass concentration of 99.5%) is sent to the MIBK synthesis system for reuse as target product 2 from acetone outlet C of acetone reflux tank 16. The ratio of the two portions of acetone solution is 6.3:1. (6) Stripping Section: The mixed liquid of MIBK, heavy components, and water from the first pre-fractionation section is stripped with the aqueous solution from the second pre-fractionation section in the stripping section. Heat and mass transfer occur between the stripped liquid and the reflux gas from the lower reflux port G of the distillation column 2. The stripped acetone gas flows upward into the second pre-fractionation section, while the mixed liquid of MIBK, heavy components, and water flows downward. A portion of the mixed liquid flows from the bottom outlet H of the distillation column 2 to the reboiler 18, where it is heated. The acetone in the mixed liquid is heated and evaporated into gas, which then enters the stripping section from the lower reflux port G of the distillation column 2 as the gas phase. Another portion of the mixed liquid (temperature 98°C, containing 67.27% MIBK by mass, the remainder being heavy components and water) flows from the bottom outlet J of the distillation column 2 as the target product three—(light component removed) MIBK solution—to the MIBK distillation system in the boundary area to distill MIBK products. Examples of operational results using this invention include... Figure 4 As shown in the table below, Figure 4 The display shows the performance evaluation results of the 10,000-ton / year MIBK light component removal unit.

Claims

1. A distillation system for removing light components using MIBK, comprising a distillation column, characterized in that: The distillation column includes a cylindrical column body with a vertical partition plate (3) inside the column. The partition plate (3) is vertically set and fixedly connected to the top of the column body. The top of the column body is provided with an azeotrope outlet A and an acetone outlet B. The upper side of the column body is provided with an azeotrope reflux port C and an acetone reflux port D. The middle side of the column body is provided with a raw material inlet E and an acetone aqueous solution inlet F. The lower part of the column body is provided with a reflux port G and a bottom liquid sidewall outlet H. The bottom of the column body is provided with a bottom liquid outlet J. The azeotrope outlet A, the azeotrope reflux port C, and the raw material inlet E are located on the same side of the partition plate (3). The acetone outlet B, the acetone reflux port D, and the acetone aqueous solution inlet F are located on the same side of the partition plate (3). The reflux port G, the bottom liquid outlet H, and the bottom liquid outlet J are located below the partition plate (3). Inside the column, the upper part of one side of the partition plate is an azeotropic rectification section and the lower part is a first pre-fractionation section; the upper part of the other side of the partition plate is an acetone rectification section and the lower part is a second pre-fractionation section; the column body located below the partition plate is a stripping section; the upper part of the first pre-fractionation section is a first pre-fractionation section rectification layer (2-3) and the lower part is a first pre-fractionation section stripping layer (2-4); the bottom height of the first pre-fractionation section stripping layer (2-4) is not lower than the bottom height of the partition plate (3); the raw material inlet E is located between the first pre-fractionation section rectification layer (2-3) and the first pre-fractionation section stripping layer (2-4); the column body is provided with a raw material feed pipe (2-1) connected to the raw material inlet E; the raw material feed pipe (2-1) is located in the gap between the first pre-fractionation section rectification layer (2-3) and the first pre-fractionation section stripping layer (2-4); The azeotropic rectification section is located between the first pre-fractionation section rectification layer (2-3) and the azeotropic outlet A at the top of the column. The azeotropic rectification section is provided with an azeotropic rectification section rectification layer (2-5), which is spaced apart from the first pre-fractionation section rectification layer (2-3). The stripping section is provided with a stripping layer (2-8), and there is a gap between the stripping layer (2-8) and the partition plate (3). A stripping liquid distributor (2-9) is installed horizontally in the gap. The upper part of the second pre-fractionation section is the second pre-fractionation section rectification layer (2-13), and the lower part is the second pre-fractionation section stripping layer (2-14). The bottom height of the second pre-fractionation section stripping layer (2-14) is not lower than the bottom of the partition plate (3). The acetone aqueous solution inlet F is located between the second pre-fractionation section rectification layer (2-13) and the second pre-fractionation section stripping layer (2-14). The column body is provided with an acetone aqueous solution feed pipe (2-11) connected to the acetone aqueous solution inlet F. The acetone aqueous solution feed pipe (2-11) is located in the gap between the second pre-fractionation section rectification layer (2-13) and the second pre-fractionation section stripping layer (2-14). The acetone rectification section is located between the second pre-fractionation section rectification layer (2-13) and the top acetone outlet B of the distillation column (2). The acetone rectification section is provided with an acetone rectification layer (2-15), and there is a gap between the acetone rectification layer (2-15) and the second pre-fractionation section rectification layer (2-13). The distillation column (2) is equipped with an azeotropic product collection tank (8), an extraction column (10), a phase separator (11), and an acetone aqueous solution collection tank (12). The distillation column is equipped with a raw material preheater (1) connected to the raw material inlet E. The azeotropic product collection tank (8) is connected between the extraction column (10) and the azeotropic product outlet A of the distillation column (2) through a pipeline. An azeotropic product collection cooler (7) is connected to the pipeline between the azeotropic product outlet A and the azeotropic product collection tank (8). The phase separator (11) is connected between the bottom of the extraction column (10) and the acetone aqueous solution collection tank (12). An extraction column feed pump (9) is provided on the pipeline between the extraction column (10) and the azeotropic product collection tank (8). The bottom outlet of the acetone aqueous solution collection tank (12) and the acetone aqueous solution inlet F are connected through a pipeline. An acetone aqueous solution feed pump (13) and an acetone aqueous solution heater (14) are provided on the pipeline between the acetone aqueous solution collection tank (12) and the acetone aqueous solution inlet F.

2. The MIBK distillation system for removing light components according to claim 1, characterized in that: A raw material inlet liquid distributor (2-2) is horizontally installed below the raw material feed pipe (2-1); there is a gap between the azeotropic distillation section rectification layer (2-5) and the first pre-fractionation section rectification layer (2-3), and a first liquid distributor (2-6) is horizontally installed in the gap; a second liquid distributor (2-12) is horizontally installed below the acetone aqueous solution feed pipe (2-11); there is a gap between the acetone distillation section rectification layer (2-15) and the second pre-fractionation section rectification layer (2-13), and a third liquid distributor (2-16) is horizontally installed in the gap.

3. The MIBK distillation system for removing light components according to claim 1, characterized in that: There is a gap between the rectification layer (2-5) of the azeotropic rectification section and the azeotropic outlet A. An azeotropic reflux port C is provided on the side wall of the gap. A first row of tubular liquid distributors (2-7) is horizontally installed at the azeotropic reflux port C. The azeotrope is refluxed sequentially through the azeotropic outlet A and the azeotropic reflux port C.

4. The MIBK distillation system for removing light components according to claim 3, characterized in that: An azeotrope condenser (4), an azeotrope reflux tank (5), and an azeotrope reflux pump (6) are connected in sequence between the azeotrope outlet A and the azeotrope reflux port C via pipes.

5. The MIBK distillation system for removing light components according to claim 1, characterized in that: There is a gap between the acetone rectification section (2-15) and the acetone outlet B. An acetone reflux port D is provided on the side wall of the gap. A second row of tubular liquid distributors (2-17) is horizontally installed at the acetone reflux port D. Acetone is refluxed sequentially through the acetone outlet B and the acetone reflux port D.

6. The MIBK distillation system for removing light components according to claim 5, characterized in that: An acetone condenser (15), an acetone reflux tank (16), and an acetone reflux pump (17) are sequentially connected between the acetone outlet B and the acetone reflux port D via pipes.

7. The MIBK distillation system for removing light components according to claim 1, characterized in that: There is a gap between the stripping layer (2-8) of the stripping section and the bottom liquid sidewall outlet H. A reflux port G is provided on the sidewall of the gap. An air inlet distributor (2-10) is horizontally installed at the reflux port G. The bottom liquid vapor is refluxed sequentially through the bottom liquid sidewall outlet H and the reflux port G. A reboiler (18) is connected between the bottom liquid sidewall outlet H and the reflux port G by a pipe.

8. The MIBK distillation system for removing light components according to claim 1, characterized in that: The ratio of the horizontal cross-sectional area of ​​the azeotropic distillation section (2-5) to the acetone distillation section (2-15), the first pre-fractionation section (2-3) to the second pre-fractionation section (2-13), and the first pre-fractionation section stripping section (2-4) to the second pre-fractionation section stripping section (2-14) is 1:10 to 10:

1.

9. The MIBK distillation system for removing light components according to claim 1, characterized in that: The rectification layers (2-5) of the azeotropic rectification section, the rectification layer (2-15) of the acetone rectification section, the rectification layer (2-3) of the first pre-fractionation section, the rectification layer (2-13) of the second pre-fractionation section, the stripping layer (2-4) of the first pre-fractionation section, and the stripping layer (2-14) of the second pre-fractionation section are all packed layers with a height of 2-12 meters; the stripping layer (2-8) of the stripping section is a packed layer with a height of 2-12 meters.

10. A method for removing light components using a distillation system for MIBK removal according to any one of claims 1-9, characterized in that, It includes The following work sections: (1) First pre-fractionation section: The raw material from the MIBK synthesis system, namely the organic mixture, is preheated by the raw material preheater (1) and then enters the first pre-fractionation section of the distillation column (2) through the raw material inlet E for pre-fractionation. After pre-fractionation, the organic mixture is initially fractionated. The mixture of MIBK, heavy components and water flows downward and is first stripped through the stripping layer (2-4) of the first pre-fractionation section before going to the stripping section. The azeotropic gas of 2-MPA and acetone flows upward and is first refined through the rectification layer (2-3) of the first pre-fractionation section before going to the azeotropic rectification section. (2) Azeotropic distillation section: The azeotropic gas of 2-MPA and acetone from the first pre-fractionation section distillation layer (2-3) is distilled in the azeotropic distillation section distillation layer (2-5), and undergoes heat and mass transfer with the azeotropic solution refluxed from the azeotropic reflux port C on the upper side of the distillation column (2). The azeotropic solution flows downward into the first pre-fractionation section. The azeotropic gas after distillation exits the distillation column (2) from the azeotropic outlet A at the top of the distillation column (2) and is condensed into a liquid by the azeotropic condenser (4). The solution enters the azeotropic reflux tank (5). A portion of the azeotropic solution in the azeotropic reflux tank (5) is discharged as reflux liquid from the reflux liquid outlet B of the azeotropic reflux tank (5) and enters the azeotropic rectification section of the distillation column (2) from the azeotropic reflux port C on the upper side of the distillation column (2) through the azeotropic reflux pump (6). The other portion of the azeotropic solution in the azeotropic reflux tank (5) is discharged as product from the product outlet C of the azeotropic reflux tank (5) to the azeotropic extraction section. The ratio of the two portions of the azeotropic solution is 378:

1. (3) Azeotropic Extraction Section: The azeotropic solution of 2-MPA and acetone from the azeotropic distillation section is first cooled by the azeotropic extractor cooler (7), and then enters the azeotropic extractor tank (8). The azeotropic solution in the azeotropic extractor tank (8) is fed into the extraction tower (10) from the upper inlet through the extraction tower feed pump (9). Water from the boundary area enters the extraction tower (10) from the upper inlet A. In the extraction tower (10), the acetone in the azeotropic solution enters the water and forms an acetone aqueous solution. MPA is insoluble in water; after extraction, the mixture of acetone aqueous solution and 2-MPA solution exits from the lower outlet C of the extraction tower (10) and enters the phase separator (11) through the middle inlet A. In the phase separator (11), the acetone aqueous solution and 2-MPA solution are separated. The acetone aqueous solution enters the lower layer of the phase separator (11) and goes to the second pre-fractionation section from the bottom outlet C of the phase separator (11). The 2-MPA solution enters the upper layer of the phase separator (11) and goes to the target product boundary area from the upper outlet B of the phase separator (11). (4) Second pre-fractionation section: The acetone aqueous solution from the azeotropic extraction section enters the acetone aqueous solution collection tank (12), and is sent to the acetone aqueous solution heater (14) by the acetone aqueous solution feed pump (13) for heating. After heating, the acetone aqueous solution enters the second pre-fractionation section of the distillation column (2) through the acetone aqueous solution inlet F for pre-fractionation. After pre-fractionation, the acetone aqueous solution is initially fractionated. The aqueous solution flows downward and is first stripped through the second pre-fractionation section stripping layer (2-14) before going to the stripping section. The acetone gas flows upward and is first rectified through the second pre-fractionation section rectification layer (2-13) before going to the acetone rectification section. (5) Acetone distillation section: Acetone gas from the second pre-fractionation section distillation layer (2-13) is distilled in the acetone distillation section distillation layer (2-15), and undergoes heat and mass transfer with the acetone solution refluxed from the acetone reflux port D on the upper side of the distillation column (2). The acetone solution flows downward into the second pre-fractionation section. The distilled acetone gas exits the distillation column (2) from the acetone outlet B at the top of the distillation column (2) and is condensed into liquid by the acetone condenser (15) before entering the acetone reflux tank. (16) A portion of the acetone solution in the acetone reflux tank (16) is discharged as reflux liquid from the reflux outlet B of the acetone reflux tank (16) and enters the acetone rectification section of the distillation column (2) from the acetone reflux port D on the upper side of the distillation column (2) through the acetone reflux pump (17). Another portion of the acetone solution in the acetone reflux tank (16) is discharged as target product II from the acetone outlet C of the acetone reflux tank (16) to the MIBK synthesis system for reuse. The ratio of the two portions of acetone solution is 6.3:

1. (6) Stripping section: The mixed liquid of MIBK, heavy components and water from the first pre-fractionation section and the aqueous solution from the second pre-fractionation section are stripped in the stripping section. Heat and mass transfer are carried out with the gas phase refluxed from the bottom reflux port G of the distillation column (2). The stripped acetone gas flows upward into the second pre-fractionation section, and the mixed liquid of MIBK, heavy components and water flows downward. Part of the mixed liquid goes from the bottom liquid outlet H of the distillation column (2) to the reboiler (18). In the reboiler (18), the mixed liquid is heated and the acetone in the mixed liquid is heated and evaporated into gas as gas phase and enters the stripping section from the bottom reflux port G of the distillation column (2). Another part of the mixed liquid goes from the bottom liquid outlet J of the distillation column (2) as target product three, namely MIBK solution, to the MIBK distillation system of the boundary area to distill MIBK product.

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