Rectification system and rectification method for removing light components from MIBK

Abstract

The invention discloses a rectification system and a rectification method for removing light components from MIBK, and belongs to the technical field of chemical rectification. The rectification system comprises a rectification tower, the rectification tower comprises a tower body with a cylindrical barrel structure, and a vertical partition plate is arranged in the tower body and divides the rectification tower into a first pre-fractionation section, an azeotrope rectification section, a stripping section, a second pre-fractionation section and an acetone rectification section. By adopting the rectification equipment, an organic matter mixed solution containing light components such as 2-MPA and acetone from an MIBK synthesis system can be rectified, extracted and separated. A target product 2-MPA debounded region is obtained in the extraction section; a target product diacetone obtained in an acetone rectifying section of the rectifying tower is directly returned to an MIBK synthesis system as a raw material for use; a target product tri-MIBK solution obtained in the stripping section of the rectifying tower is subjected to boundary region rectification, and MIBK is separated. By utilizing the rectification system, the number of equipment can be reduced, the technological process is simplified, the device investment is reduced, the raw material and energy consumption in production is reduced, the production cost is reduced, and the carbon emission of a production device is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of chemical distillation, and in particular to a distillation system and a distillation method for removing light components from MIBK. Background Art

[0002] MIBK chemical name methyl isobutyl ketone, also known as 4-methyl-2-pentanone, is an organic compound with the chemical formula C6H 12 O, mainly used as a solvent for spray paint, nitrocellulose, certain cellulose ethers, camphor, oils and fats, natural and synthetic rubber.

[0003] In the MIBK synthesis system, for every ton of MIBK product synthesized, about 2,824 kg of light components containing raw material acetone and byproduct 2-MPA will be produced, of which about 2,802 kg of acetone and about 22 kg of 2-MPA are contained. These organic light components need to be distilled, extracted, and distilled to recover useful components. In the existing production, a two-step distillation process is usually adopted. Step 1: purify and recover the azeotrope through the azeotrope distillation separation and recovery system, and the azeotrope goes to the extraction system to recover the target product one - 2-MPA. The acetone aqueous solution produced by the extraction system is mixed with the tower bottom liquid produced by the azeotrope distillation separation and recovery system; Step 2: The tower bottom mixed liquid produced in step 1 is sent to the acetone distillation separation and recovery system to recover the target product two - acetone, and the tower bottom liquid is used as the target product three - MIBK solution (removing light components). The above light components such as 2-MPA and acetone 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, but the energy consumption of the distillation process is huge. More than 50% of the energy consumption in chemical production is used for separation, and the energy consumption of distillation separation accounts for 95% of it.

[0004] Therefore, it is necessary to improve the existing distillation equipment for the separation and recovery of light components such as 2-MPA and acetone, and it is urgent to provide a distillation equipment for removing light components from MIBK with a short process, small footprint, low investment and low energy consumption. Summary of the invention

[0005] The object of the present invention is to provide a distillation system for removing light components from MIBK with a short process, small footprint, low investment and low energy consumption, which is used for distilling, extracting and separating an organic mixed liquid containing light components such as 2-MPA and acetone from a MIBK synthesis system. At the same time, the present invention also provides a distillation method for removing light components from MIBK.

[0006] The distillation system for removing light components from MIBK of the present invention adopts the following technical scheme: a distillation system for removing light components from MIBK, comprising a distillation tower, the distillation tower comprising a tower body with a cylindrical barrel structure, a partition plate of a vertical structure is arranged in the tower body, the upper end of the partition plate is vertically arranged and fixedly connected to the top of the tower body, the top of the tower body is provided with an azeotrope outlet A and an acetone outlet B, the upper side of the tower body is provided with an azeotrope reflux port C and an acetone reflux port D, the side of the middle of the tower body is provided with a raw material inlet E and an acetone aqueous solution inlet F, the lower part of the tower body is provided with a reflux port G and a tower bottom liquid side wall outlet H, the bottom of the tower body is provided with a tower 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 same other side of the partition plate, and the reflux port G, the tower bottom liquid outlet H, and the tower bottom liquid outlet J are located below the partition plate; In the tower body, the upper part of one side of the partition plate is the azeotrope distillation section, and the lower part is the first pre-fractionation section; the upper part of the other side of the partition plate is the acetone distillation section, and the lower part is the second pre-fractionation section; the position below the partition plate in the tower body is the stripping section; the upper part of the first pre-fractionation section is the first pre-fractionation section distillation layer, and the lower part is the first pre-fractionation section stripping layer, and the bottom end height of the first pre-fractionation section stripping layer is not lower than the bottom end of the partition plate; the raw material inlet E is located between the first pre-fractionation section distillation layer and the first pre-fractionation section stripping layer, and a raw material feed pipe connected to the raw material inlet E is provided in the tower body, and the raw material feed pipe is located in the gap between the first pre-fractionation section distillation layer and the first pre-fractionation section stripping layer; The azeotrope distillation section is located between the azeotrope outlet A above the first pre-fractionation section distillation layer and the top of the tower body, and the azeotrope distillation section distillation layer is provided in the azeotrope distillation section, and the azeotrope distillation section distillation layer is spaced from the first pre-fractionation section distillation layer; The stripping section is provided with a stripping layer of the stripping section, a gap is provided between the stripping layer of the stripping section and the partition plate, and a stripping section liquid distributor is horizontally installed in the gap; The upper part of the second pre-fractionation section is the second pre-fractionation section rectifying layer, and the lower part is the second pre-fractionation section stripping layer, and the height of the bottom end of the second pre-fractionation section stripping layer is not lower than the bottom end of the partition plate; the acetone aqueous solution inlet F is located between the second pre-fractionation section rectifying layer and the second pre-fractionation section stripping layer, and an acetone aqueous solution feed pipe connected to the acetone aqueous solution inlet F is provided in the tower body, and the acetone aqueous solution feed pipe is located in the gap between the second pre-fractionation section rectifying layer and the second pre-fractionation section stripping layer; The acetone distillation section is located between the distillation layer above the second pre-fractionation section and the acetone outlet B at the top of the distillation tower. The acetone distillation section is provided with a distillation layer of the acetone distillation section, and there is a gap between the distillation layer of the acetone distillation section and the distillation layer of the second pre-fractionation section. The distillation tower is provided with an azeotrope extraction tank, an extraction tower, a phase separator and an acetone aqueous solution extraction tank outside the distillation tower. A raw material preheater connected to a raw material inlet E is provided outside the distillation tower. The azeotrope extraction tank is connected between the extraction tower and the azeotrope outlet A of the distillation tower through a pipeline, and an azeotrope extraction cooler is connected to the pipeline between the azeotrope outlet A and the azeotrope extraction tank; the phase separator is connected between the bottom of the extraction tower and the acetone aqueous solution extraction tank, and an extraction tower feed pump is provided on the pipeline between the extraction tower and the azeotrope extraction tank; the bottom outlet of the acetone aqueous solution extraction tank and the acetone aqueous solution inlet F are connected through a pipeline, and an acetone aqueous solution feed pump and an acetone aqueous solution heater are provided on the pipeline between the acetone aqueous solution extraction 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 distillation layer of the azeotrope distillation section and the distillation 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 distillation layer of the acetone distillation section and the distillation 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 distillation layer of the azeotrope distillation section and the azeotrope outlet A, and an azeotrope reflux port C is provided on the side wall of the gap. A first row of tubular liquid distributors is horizontally installed at the azeotrope reflux port C, and the azeotrope refluxes through the azeotrope outlet A and the azeotrope reflux port C in sequence.

[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 through pipelines.

[0010] There is a gap between the distillation layer of the acetone distillation section and the acetone outlet B, and 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, and acetone refluxes through the acetone outlet B and the acetone reflux port D in sequence.

[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 through pipelines.

[0012] There is a gap between the stripping layer of the stripping section and the bottom liquid side wall outlet H, a reflux port G is provided on the side wall of the gap, an air inlet distributor is horizontally installed at the reflux port G, and the bottom steam is refluxed through the bottom liquid side wall outlet H and the reflux port G in turn.

[0013] A reboiler is connected between the tower bottom liquid side wall outlet H and the reflux port G via a pipeline.

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

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

[0016] The method for removing light components from MIBK by using the above-mentioned distillation system for removing light components from MIBK comprises the following steps: (1) The first pre-fractionation section: The raw material from the MIBK synthesis system, i.e., the organic mixed liquid, is preheated by the raw material preheater and then enters the first pre-fractionation section of the distillation tower from the raw material inlet E of the first pre-fractionation section of the distillation tower for pre-fractionation. After the pre-fractionation, the organic mixed liquid is preliminarily fractionated; the mixed liquid of MIBK, heavy components and water flows downward and is first distilled in the stripping layer of the first pre-fractionation section, and then goes to the stripping section; the azeotropic gas of 2-MPA and acetone flows upward and is first distilled in the distillation layer of the first pre-fractionation section, and then goes to the azeotropic distillation section; (2) Azeotropic distillation section: The azeotropic gas of 2-MPA and acetone from the distillation layer of the first pre-fractionation section is distilled in the distillation layer of the azeotropic distillation section, and heat and mass transfer is carried out with the azeotropic solution refluxed from the azeotropic reflux port C on the upper side of the distillation tower. The azeotropic solution flows downward into the first pre-fractionation section. The azeotropic gas after distillation leaves the distillation tower from the azeotropic outlet A on the top of the distillation tower, and is condensed into liquid through the azeotropic condenser and then enters the azeotropic reflux tank. A part of the azeotropic solution in the azeotropic reflux tank is discharged from the azeotropic reflux tank reflux liquid outlet B as reflux liquid and enters the azeotropic distillation section of the distillation tower through the azeotropic reflux port C on the upper side of the distillation tower through the azeotropic reflux pump. Another part of the azeotropic solution in the azeotropic reflux tank is taken as produced product from the azeotropic reflux tank produced product outlet C to the azeotropic extraction section. The ratio of the two parts of the azeotropic solution is 378:1. (3) Azeotrope extraction section: The azeotrope solution of 2-MPA and acetone from the azeotrope distillation section is first cooled by an azeotrope extraction cooler and then enters the azeotrope extraction tank. The azeotrope solution in the azeotrope extraction 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 zone enters the extraction tower from the upper inlet A of the extraction tower. In the extraction tower, acetone in the azeotrope solution enters the water and forms an acetone aqueous solution with water. 2-MPA is insoluble in water. After extraction, the mixed solution consisting of the acetone aqueous solution and the 2-MPA solution exits the extraction tower from the lower outlet C of the extraction tower and enters the phase separator through the middle inlet A of the phase separator. In the phase separator, the acetone aqueous solution and the 2-MPA solution are phase-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 zone from the upper outlet B of the phase separator as the target product. (4) Second pre-fractionation section: The acetone aqueous solution from the azeotrope extraction section enters the acetone aqueous solution extraction tank, and is sent to the acetone aqueous solution heater by the acetone aqueous solution feed pump for heating. After the acetone aqueous solution is heated, it enters the second pre-fractionation section of the distillation tower from the acetone aqueous solution inlet F of the second pre-fractionation section of the distillation tower for pre-fractionation. After the pre-fractionation, the acetone aqueous solution is preliminarily fractionated; the aqueous solution flows downward and is first distilled in the stripping layer of the second pre-fractionation section, and then goes to the stripping section; the acetone gas flows upward and is first distilled in the distillation layer of the second pre-fractionation section, and then goes to the acetone distillation section; (5) Acetone distillation section: The acetone gas from the distillation layer of the second pre-fractionation section is distilled in the distillation layer of the acetone distillation section, and heat and mass transfer is carried out with the acetone solution refluxed from the acetone reflux port D on the upper side of the distillation tower. The acetone solution flows downward and enters the second pre-fractionation section. The acetone gas after distillation leaves the distillation tower from the acetone outlet B at the top of the distillation tower and is condensed into liquid through the acetone condenser and then enters the acetone reflux tank. A part of the acetone solution in the acetone reflux tank is used as reflux liquid and leaves the acetone reflux tank. The reflux liquid outlet of the acetone reflux tank passes through the acetone reflux pump and enters the acetone distillation section of the distillation tower from the acetone reflux port D on the upper side of the distillation tower. Another part of the acetone solution in the acetone reflux tank is used as the target product II and is reused in the MIBK synthesis system from the acetone outlet of the acetone reflux tank. The ratio of the two parts of acetone solution is 6.3:1. (6) Distillation 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, and heat and mass transfer is carried out with the gas phase refluxed from the reflux port G at the lower part of the distillation tower. The acetone gas after stripping flows upward into the second pre-fractionation section, and the mixed liquid of MIBK, heavy components and water flows downward. A part of the mixed liquid goes to the reboiler from the bottom liquid outlet H of the distillation tower, where the mixed liquid is heated, and the acetone in the mixed liquid is heated and evaporated into gas as the gas phase and enters the stripping section from the reflux port G at the lower part of the distillation tower. Another part of the mixed liquid is taken from the bottom liquid outlet H of the distillation tower as the target product three, i.e., MIBK solution, and the MIBK product is distilled by the MIBK distillation system in the deboundary zone.

[0017] The beneficial effect of the present invention is that in the MIBK synthesis system, about 2824 kg of light components containing raw material component acetone and byproduct 2-MPA are generated for every 1 ton of MIBK synthesized, of which about 2802 kg of acetone and about 22 kg of 2-MPA are contained. The present invention provides a distillation system and method for removing light components from MIBK, and the distillation system and method can be used to effectively recover acetone and 2-MPA, and about 992.2 kg of acetone and about 7.8 kg of 2-MPA can be recovered for every 1 ton of light components removed.

[0018] The distillation tower of the present invention adopts a partition plate distillation tower to replace the azeotrope distillation tower and the acetone distillation tower, combines the two distillation towers into one, and saves a reboiler at the same time, saving about 25% of equipment investment. The boiling points of the azeotrope and acetone are close, and the distillation section of the distillation tower is divided into an azeotrope distillation section and an acetone distillation section, which is conducive to the distillation of two light components. Acetone appears in the azeotrope distillation section and the acetone distillation section at the same time, and the raw material composition entering the raw material inlet of the partition plate distillation tower and the acetone aqueous solution composition entering the acetone aqueous solution inlet can be well matched with the composition on the first pre-fractionation section and the second pre-fractionation section liquid distributor, reducing the mixing effect at the liquid distributor, that is, reducing the mixing effect caused by the different composition of the feed and the liquid distributor, meeting the requirements of the optimal liquid distributor, and improving the thermodynamic efficiency. Since the heat of the partition plate distillation tower is repeatedly recycled in the same tower, energy consumption is also saved, and the energy consumption saved is about 25%.

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

[0020] The present invention can realize the distillation, extraction and separation of an organic mixed liquid containing light components such as 2-MPA and acetone from a MIBK synthesis system, wherein the target product one recovered by a phase separator is the 2-MPA delimiting zone, the target product two recovered by an acetone reflux tank is the acetone delimiting zone for reuse in the MIBK synthesis system, and the target product three recovered by a distillation tower is the MIBK product of the MIBK distillation system delimiting zone of the MIBK solution (with the light components removed).

[0021] Different from the distillation tower in the prior art, the present invention sets a vertical partition plate in the distillation tower, two feed ports are set on both sides of the partition plate, two gas outlets are set on the top of the distillation tower, two liquid reflux ports are set on the upper part, and the distillation tower is provided with two distillation sections. The azeotrope recovered in the azeotrope distillation section of the distillation tower is used to recover the target product one, namely 2-MPA in the extraction section; the target product two, namely acetone, is recovered in the acetone distillation section of the distillation tower and is directly reused in the MIBK synthesis system as a raw material; the target product three, namely MIBK solution (with light components removed) is recovered in the stripping section of the distillation tower and the MIBK product is distilled in the MIBK distillation system in the boundary zone.

[0022] By adopting the technical solution of the present invention, only one set of distillation system is needed to recover the target product. The present invention is a distillation system and method for removing light components from MIBK with a short process, small footprint, low investment and low energy consumption. The present invention has the advantages of energy saving and consumption reduction, reduced investment in production equipment, reduced carbon emissions and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A process flow diagram of a distillation system for removing light components from MIBK according to an embodiment of the present invention; Figure 2 for Figure 1 Schematic diagram of the distillation column in; Figure 3 for Figure 1 The working section division diagram of the distillation tower in FIG. Figure 4 This is the performance evaluation result table of the 10,000 tons / year MIBK light component removal device.

[0024] Among them, 1, raw material preheater, 2, distillation tower, 2-1, raw material feed pipe, 2-2, raw material inlet liquid distributor, 2-3, first pre-fractionation section distillation layer, 2-4, first pre-fractionation section stripping layer, 2-5, azeotropic distillation section distillation layer, 2-6, first liquid distributor, 2-7, first row of tube liquid distributor, 2-8, stripping section stripping layer, 2-9, stripping section liquid distributor, 2-10, air inlet distributor, 2-11, acetone aqueous solution feed pipe, 2-12, second liquid distributor, 2-13, second pre-fractionation section distillation layer, 2-14, second pre Distillation layer of fractionation section, 2-15, distillation layer of acetone distillation section, 2-16, third liquid distributor, 2-17, second row of tubular liquid distributor, 3, partition plate, 4, azeotrope condenser, 5, azeotrope reflux tank, 6, azeotrope reflux pump, 7, azeotrope extraction cooler, 8, azeotrope extraction tank, 9, extraction tower feed pump, 10, extraction tower, 11, phase separator, 12, acetone aqueous solution extraction 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 DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. The components of the embodiment of the present invention described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but only represents the selected embodiment of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and cannot be understood as limitations on the present invention.

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

[0027] The distillation system for removing light components from MIBK according to one embodiment of the present invention is as follows Figure 1As shown, it includes a distillation tower, and a raw material preheater 1, an azeotrope condenser 4, an azeotrope reflux tank 5, an azeotrope reflux pump 6, an azeotrope extraction cooler 7, an azeotrope extraction tank 8, an extraction tower feed pump 9, an extraction tower 10, a phase separator 11, an acetone aqueous solution extraction 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, which are arranged outside the distillation tower 2.

[0028] The structure of the distillation tower is as follows: Figure 2 , 3 As shown, the distillation tower can distill, extract and separate the organic mixed liquid containing 2-MPA, acetone and other light components from the MIBK synthesis system; the distillation tower includes a tower body with a cylindrical barrel structure, and a vertical partition plate 3 is arranged in the tower body, and the partition plate 3 directly reaches the top of the distillation tower 2. The top of the distillation tower 2 is provided with an azeotrope outlet A and an acetone outlet B, the upper side of the distillation tower 2 is provided with an azeotrope reflux port C and an acetone reflux port D, the middle side of the distillation tower 2 is provided with a raw material inlet E and an acetone aqueous solution inlet F, the lower part of the distillation tower 2 is provided with a reflux port G and a tower bottom liquid outlet H, and the bottom of the distillation tower 2 is provided with a tower 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 other side of the partition plate 3, and the reflux port G, the tower bottom liquid outlet H, and the tower bottom liquid outlet J are located below the partition plate 3.

[0029] like Figure 2-3 As shown, the upper part of the azeotrope outlet A, azeotrope reflux port C, and raw material inlet E of the distillation tower 2 partition plate 3 is the azeotrope distillation 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 distillation layer 2-3, and the lower part is the first pre-fractionation section stripping layer 2-4. The bottom end of the first pre-fractionation section stripping layer 2-4 is not lower than the bottom end of the partition plate 3. There is a gap between the first pre-fractionation section distillation layer 2-3 and the first pre-fractionation section stripping layer 2-4. A raw material feed pipe 2-1 is horizontally installed at the raw material inlet E of the side wall of the gap, and a raw material inlet liquid distributor 2-2 is horizontally installed below the raw material feed pipe 2-1. The area from the first pre-fractionation section distillation layer 2-3 to the azeotrope outlet A at the top of the distillation tower 2 is the azeotrope distillation section, and the middle of the azeotrope distillation section is the azeotrope distillation section distillation layer 2-5. There is a gap between the azeotrope distillation section distillation layer 2-5 and the first pre-fractionation section distillation layer 2-3, and a first liquid distributor 2-6 is horizontally installed in the gap. There is a gap between the azeotrope distillation section distillation layer 2-5 and the azeotrope outlet A, and an azeotrope 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 azeotrope reflux port C, and the azeotrope is refluxed through the azeotrope outlet A and the azeotrope reflux port C in turn.

[0030] like Figure 2-3As shown, the middle part of the stripping section is the stripping layer 2-8 of the stripping section, there is a gap between the stripping layer 2-8 of the stripping section and the partition plate 3, and the stripping section liquid distributor 2-9 is horizontally installed in the gap; there is a gap between the stripping layer 2-8 of the stripping section and the bottom liquid outlet H, a reflux port G is provided on the side wall of the gap, an air inlet distributor 2-10 is horizontally installed at the reflux port G, and the bottom steam is refluxed via the bottom liquid outlet H and the reflux port G in turn.

[0031] like Figure 2-3 As shown, the upper part of the acetone outlet B, acetone reflux port D, and acetone aqueous solution inlet F of the distillation tower 2 is the acetone distillation 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 distillation layer 2-13, and the lower part is the second pre-fractionation section stripping layer 2-14. The bottom end of the second pre-fractionation section stripping layer 2-14 is not lower than the bottom end of the partition plate 3. There is a gap between the second pre-fractionation section distillation 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 side wall of the gap, and 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 distillation layer 2-13 to the acetone outlet B at the top of the distillation tower 2 is the acetone distillation section. The middle of the acetone distillation section is the acetone distillation section distillation layer 2-15. There is a gap between the acetone distillation section distillation layer 2-15 and the second pre-fractionation section distillation layer 2-13. A third liquid distributor 2-16 is horizontally installed in the gap. There is a gap between the acetone distillation section distillation layer 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 refluxes 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 area of ​​the azeotrope rectifying section rectifying layer 2-5 to the acetone rectifying section rectifying layer 2-15, the first pre-fractionation section rectifying layer 2-3 to the second pre-fractionation section rectifying layer 2-13, the first pre-fractionation section stripping layer 2-4 to the second pre-fractionation section stripping layer 2-14 is 64:100; the azeotrope rectifying section rectifying layer 2-5, the first pre-fractionation section rectifying layer 2-3, the first pre-fractionation section stripping layer 2-4, and the acetone rectifying section rectifying layer 2-15 are all packing layers with a height of 3 meters, the second pre-fractionation section rectifying layer 2-13 and the second pre-fractionation section stripping layer 2-14 are all packing layers with a height of 4 meters. The stripping section stripping layer 2-8 is a packing layer with a height of 3 meters.

[0033] The raw material from the MIBK synthesis system, the organic matter mixed liquid pipeline, is connected to the raw material inlet E on the middle side of the distillation tower 2 through the raw material preheater 1, and the azeotrope outlet A at the top of the distillation tower 2 is connected in sequence to the azeotrope condenser 4, the azeotrope reflux tank 5, the azeotrope extraction cooler 7, the azeotrope extraction tank 8, the extraction tower feed pump 9 and the upper inlet B of the extraction tower 10. The lower outlet C of the extraction tower 10 is connected to the middle inlet A of the phase separator 11, and the upper outlet B of the phase separator 11 is connected to the target product of the deboundary zone, namely, the 2-MPA pipeline.

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

[0035] The bottom kettle liquid outlet J of the distillation tower 2 is connected to the target product three of the deboundary area - MIBK solution pipeline.

[0036] The lower outlet B of the azeotrope reflux tank 5 is connected to the azeotrope reflux port C at the upper part of the distillation tower 2 through the azeotrope reflux pump 6; the lower outlet B of the acetone reflux tank 16 is connected to the acetone reflux port D at the upper part of the distillation tower 2 through the acetone reflux pump 17; the lower bottom liquid outlet H of the distillation tower 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 tower 2.

[0037] The water pipe from the boundary area is connected to the upper inlet A of the extraction tower 2. The specific embodiment of the method for removing light components from MIBK using the above-mentioned distillation system of the present invention includes the following steps: (1) The first pre-fractionation section: The raw material from the MIBK synthesis system - the organic mixed liquid (temperature 45°C, containing 0.55% 2-MPA mass concentration, 69.06% acetone mass concentration, 24.65% MIBK mass concentration, and the rest being heavy components and water) is preheated by the raw material preheater 1 (temperature 64°C) and then enters the first pre-fractionation section of the distillation tower 2 from the raw material inlet E of the first pre-fractionation section of the distillation tower 2 for pre-fractionation. After pre-fractionation, the organic mixed liquid is preliminarily fractionated. The mixed liquid of MIBK, heavy components and water flows downward and is first distilled in the first pre-fractionation section stripping layer 2-4, and then goes to the stripping section; the azeotropic gas of 2-MPA and acetone flows upward and is first distilled in the first pre-fractionation section stripping layer 2-3, and then goes to the azeotropic section; (2) Azeotropic distillation section: The azeotropic gas of 2-MPA and acetone from the distillation layer 2-3 of the first pre-fractionation section is distilled in the distillation layer 2-5 of the azeotropic distillation section, and heat and mass transfer is carried out with the azeotropic solution refluxed from the azeotropic reflux port C on the upper side of the distillation tower 2. The azeotropic solution flows downward into the first pre-fractionation section. The azeotropic gas after distillation (temperature 55°C, 25% 2-MPA mass concentration, 75% acetone mass concentration) exits the distillation tower 2 from the azeotropic outlet A at the top of the distillation tower 2 and passes through the azeotropic distillation column 2. The azeotropic condenser 4 condenses the liquid (temperature 55°C) and then enters the azeotropic reflux tank 5. A portion of the azeotropic solution in the azeotropic reflux tank 5 is discharged from the azeotropic reflux tank 5 reflux liquid outlet B as reflux liquid and enters the azeotropic distillation section of the distillation tower 2 from the azeotropic reflux port C on the upper side of the distillation tower 2 through the azeotropic reflux pump 6. Another portion of the azeotropic solution in the azeotropic reflux tank 5 is taken as the produced product from the produced 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) Azeotrope extraction section: The azeotrope solution of 2-MPA and acetone from the azeotrope distillation section is first cooled by the azeotrope extraction cooler 7 (temperature 45°C), and then enters the azeotrope extraction tank 8. The azeotrope solution in the azeotrope extraction tank 8 is fed into the extraction tower 10 from the upper inlet B of the extraction tower 10 by the extraction tower feed pump 9. Water from the boundary zone enters the extraction tower 10 from the upper inlet A of the extraction tower 10. In the extraction tower 10, the acetone in the azeotrope solution enters the water and forms an acetone aqueous solution with the water. 2-MPA is insoluble in water. After extraction, the mixed solution consisting of the acetone aqueous solution and the 2-MPA solution leaves the extraction tower 10 from the lower outlet C of the extraction tower 10 and enters the phase separator 11 through the middle inlet A of the phase separator 11. In the phase separator 11, the acetone aqueous solution and the 2-MPA solution are phase-separated. The acetone aqueous solution (containing acetone at a mass concentration of 19.95% and the rest being water) 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 (containing 2-MPA at a mass concentration of 99%) enters the upper layer of the phase separator 11 and goes to the boundary zone as the target product 1 from the upper outlet B of the phase separator 11. (4) Second pre-fractionation section: The acetone aqueous solution from the azeotrope extraction section enters the acetone aqueous solution extraction tank 12, and is sent to the acetone aqueous solution heater 14 by the acetone aqueous solution feed pump 13 for heating (temperature 70°C), and then enters the second pre-fractionation section of the distillation tower 2 from the acetone aqueous solution inlet F of the second pre-fractionation section of the distillation tower 2 for pre-fractionation. After pre-fractionation, the acetone aqueous solution is preliminarily fractionated. The aqueous solution flows downward and is first distilled in the second pre-fractionation section stripping layer 2-14, and then goes to the stripping section; the acetone gas flows upward and is first distilled in the second pre-fractionation section stripping layer 2-13, and then goes to the acetone stripping section; (5) Acetone distillation section: The acetone gas from the distillation layer 2-13 of the second pre-fractionation section is distilled in the distillation layer 2-15 of the acetone distillation section, and heat and mass transfer is carried out with the acetone solution refluxed from the acetone reflux port D on the upper side of the distillation tower 2. The acetone solution flows downward into the second pre-fractionation section. The rectified acetone gas (temperature 56.5°C, acetone mass concentration 99.5%) exits the distillation tower 2 from the acetone outlet B at the top of the distillation tower 2 and is condensed into liquid (temperature 56.5°C) by the acetone condenser 15. ℃) and then enters the acetone reflux tank 16, a part of the acetone solution in the acetone reflux tank 16 is used as reflux liquid and is discharged from the reflux liquid outlet B of the acetone reflux tank 16 through the acetone reflux pump 17 and enters the acetone distillation section of the distillation tower 2 from the acetone reflux port D on the upper side of the distillation tower 2, and another part of the acetone solution in the acetone reflux tank 16 (containing acetone mass concentration of 99.5%) is used as the target product 2 and is recycled to the MIBK synthesis system from the acetone outlet C of the acetone reflux tank 16, and the ratio of the two parts of the acetone solution is 6.3:1; (6) Distillation 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, and heat and mass transfer is carried out with the gas phase refluxed from the reflux port G at the lower part of the distillation tower 2. The acetone gas after stripping flows upward into the second pre-fractionation section, and the mixed liquid of MIBK, heavy components and water flows downward. A part of the mixed liquid goes to the reboiler 18 from the bottom liquid outlet H at the lower part of the distillation tower 2, where the mixed liquid is heated, and the acetone in the mixed liquid is heated and evaporated into gas as the gas phase and enters the stripping section from the reflux port G at the lower part of the distillation tower 2; another part of the mixed liquid (temperature 98°C, containing 67.27% MIBK mass concentration, the rest being heavy components and water) is distilled from the bottom liquid outlet J at the lower part of the distillation tower 2 as the target product three - the MIBK solution (light components removed) to the MIBK distillation system in the boundary zone. The operation results of the present invention are shown in FIG. Figure 4 As shown in the table, Figure 4 Shown are the performance assessment results of a 10,000 t / a MIBK light component removal unit.

Claims

1. A distillation system for removing light components from MIBK, comprising a distillation tower, characterized in that: The distillation tower comprises a tower body with a cylindrical barrel structure, wherein a vertical partition plate (3) is arranged in the tower body, the upper end of the partition plate (3) is vertically arranged and fixedly connected to the top of the tower body, the top of the tower body is provided with an azeotrope outlet A and an acetone outlet B, the upper side of the tower body is provided with an azeotrope reflux port C and an acetone reflux port D, the middle side of the tower body is provided with a raw material inlet E and an acetone aqueous solution inlet F, the lower part of the tower body is provided with a reflux port G and a bottom liquid side wall outlet H, the bottom of the tower 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 other side of the partition plate (3), and the reflux port G, the bottom liquid outlet H and the bottom liquid outlet J are located below the partition plate (3); In the tower body, the upper part of one side of the partition plate is the azeotropic distillation section, and the lower part is the first pre-fractionation section; the upper part of the other side of the partition plate is the acetone distillation section, and the lower part is the second pre-fractionation section; the position below the partition plate in the tower body is the stripping section; the upper part of the first pre-fractionation section is the first pre-fractionation section distillation layer (2-3), and the lower part is the first pre-fractionation section stripping layer (2-4); the bottom end height of the first pre-fractionation section stripping layer (2-4) is not lower than the bottom end of the partition plate (3); the raw material inlet E is located between the first pre-fractionation section distillation layer (2-3) and the first pre-fractionation section stripping layer (2-4); a raw material feed pipe (2-1) connected to the raw material inlet E is provided in the tower body, and the raw material feed pipe (2-1) is located in the gap between the first pre-fractionation section distillation layer (2-3) and the first pre-fractionation section stripping layer (2-4); The azeotrope distillation section is located between the first pre-fractionation section distillation layer (2-3) and the azeotrope outlet A at the top of the tower body, and an azeotrope distillation section distillation layer (2-5) is provided in the azeotrope distillation section, and the azeotrope distillation section distillation layer (2-5) is spaced apart from the first pre-fractionation section distillation layer (2-3); A stripping section stripping layer (2-8) is provided in the stripping section, a gap is provided between the stripping section stripping layer (2-8) and the partition plate (3), and a stripping section liquid distributor (2-9) is horizontally installed in the gap; The upper part of the second pre-fractionation section is a second pre-fractionation section rectifying layer (2-13), and the lower part is a second pre-fractionation section stripping layer (2-14), and the height of the bottom end of the second pre-fractionation section stripping layer (2-14) is not lower than the bottom end of the partition plate (3); the acetone aqueous solution inlet F is located between the second pre-fractionation section rectifying layer (2-13) and the second pre-fractionation section stripping layer (2-14), and an acetone aqueous solution feed pipe (2-11) connected to the acetone aqueous solution inlet F is provided in the tower body, and the acetone aqueous solution feed pipe (2-11) is located in the gap between the second pre-fractionation section rectifying layer (2-13) and the second pre-fractionation section stripping layer (2-14); The acetone distillation section is located between the second pre-fractionation section distillation layer (2-13) and the acetone outlet B at the top of the distillation tower (2), and an acetone distillation section distillation layer (2-15) is provided in the acetone distillation section, and a gap is provided between the acetone distillation section distillation layer (2-15) and the second pre-fractionation section distillation layer (2-13); The distillation tower (2) is provided with an azeotrope extraction tank (8), an extraction tower (10), a phase separator (11) and an acetone aqueous solution extraction tank (12) outside the distillation tower. A raw material preheater (1) connected to a raw material inlet E is provided outside the distillation tower. The azeotrope extraction tank (8) is connected between the extraction tower (10) and the azeotrope outlet A of the distillation tower (2) through a pipeline. An azeotrope extraction cooler (7) is connected to the pipeline between the azeotrope outlet A and the azeotrope extraction tank (8). The phase separator (11) is connected between the bottom of the extraction tower (10) and the acetone aqueous solution extraction tank (12). An extraction tower feed pump (9) is provided on the pipeline between the extraction tower (10) and the azeotrope extraction tank (8). The bottom outlet of the acetone aqueous solution extraction 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 extraction 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); a gap is provided between the azeotropic fractionation section fractionation layer (2-5) and the first pre-fractionation section fractionation layer (2-3), in which a first liquid distributor (2-6) is horizontally installed; a second liquid distributor (2-12) is horizontally installed below the acetone aqueous solution feed pipe (2-11); a gap is provided between the acetone fractionation section fractionation layer (2-15) and the second pre-fractionation section fractionation layer (2-13), in which a third liquid distributor (2-16) is horizontally installed.

3. The distillation system for removing light components from MIBK according to claim 1, characterized in that: A gap is provided between the distillation layer (2-5) of the azeotrope distillation section and the azeotrope outlet A, an azeotrope 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 azeotrope reflux port C, and the azeotrope refluxes sequentially through the azeotrope outlet A and the azeotrope 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 sequentially connected between the azeotrope outlet A and the azeotrope reflux port C via pipelines.

5. The MIBK distillation system for removing light components according to claim 1, characterized in that: A gap is provided between the distillation layer (2-15) of the acetone distillation 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 (2-17) is horizontally installed at the acetone reflux port D, and the acetone refluxes 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 pipelines.

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 side wall outlet H, a reflux port G is provided on the side wall of the gap, an air inlet distributor (2-10) is horizontally installed at the reflux port G, and the bottom steam is refluxed through the bottom liquid side wall outlet H and the reflux port G in sequence; a reboiler (18) is connected between the bottom liquid side wall outlet H and the reflux port G via a pipeline.

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 azeotrope distillation section distillation layer (2-5) to the acetone distillation section distillation layer (2-15), the first pre-fractionation section distillation layer (2-3) to the second pre-fractionation section distillation layer (2-13), and the first pre-fractionation section retention layer (2-4) to the second pre-fractionation section retention layer (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 azeotrope distillation section distillation layer (2-5), the acetone distillation section distillation layer (2-15), the first pre-fractionation section distillation layer (2-3), the second pre-fractionation section distillation layer (2-13), the first pre-fractionation section retention layer (2-4), and the second pre-fractionation section retention layer (2-14) are all packing layers with a height of 2 to 12 meters; the stripping section stripping layer (2-8) is a packing layer with a height of 2 to 12 meters.

10. A method for removing light components from MIBK using a distillation system for removing light components from MIBK according to any one of claims 1 to 9, characterized in that: It includes The following sections: (1) First pre-fractionation section: the raw material from the MIBK synthesis system, i.e., the organic mixed liquid, is preheated by the raw material preheater (1) and then enters the first pre-fractionation section of the distillation tower (2) from the raw material inlet E of the first pre-fractionation section of the distillation tower (2) for pre-fractionation. After the pre-fractionation, the organic mixed liquid is preliminarily fractionated; the mixed liquid of MIBK, heavy components and water flows downward and is first distilled by the first pre-fractionation section stripping layer (2-4) and then goes to the stripping section; the azeotropic gas of 2-MPA and acetone flows upward and is first distilled by the first pre-fractionation section stripping layer (2-3) and then goes to the azeotropic distillation section; (2) Azeotropic distillation section: The azeotropic gas of 2-MPA and acetone from the distillation layer (2-3) of the first pre-fractionation section is distilled in the distillation layer (2-5) of the azeotropic distillation section, and heat and mass transfer is carried out with the azeotropic solution refluxed from the azeotropic reflux port C on the upper side of the distillation tower (2). The azeotropic solution flows downward into the first pre-fractionation section. The azeotropic gas after distillation leaves the distillation tower (2) from the azeotropic outlet A at the top of the distillation tower (2) and is condensed into liquid by the azeotropic condenser (4). Entering the azeotrope reflux tank (5), a portion of the azeotrope solution in the azeotrope reflux tank (5) is discharged from the reflux liquid outlet B of the azeotrope reflux tank (5) as reflux liquid, and enters the azeotrope distillation section of the distillation tower (2) from the azeotrope reflux port C on the upper side of the distillation tower (2) through the azeotrope reflux pump (6), and another portion of the azeotrope solution in the azeotrope reflux tank (5) is discharged from the azeotrope reflux tank (5) outlet C as produced material to the azeotrope extraction section, and the ratio of the two portions of the azeotrope solution is 378:1; (3) Azeotrope extraction section: The azeotrope solution of 2-MPA and acetone from the azeotrope distillation section is first cooled by the azeotrope extraction cooler (7) and then enters the azeotrope extraction tank (8). The azeotrope solution in the azeotrope extraction tank (8) is fed into the extraction tower (10) from the upper inlet of the extraction tower (10) by the extraction tower feed pump (9). Water from the boundary zone enters the extraction tower (10) from the upper inlet A of the extraction tower (10). In the extraction tower (10), the acetone in the azeotrope solution enters the water and forms an acetone aqueous solution with the water. MPA is insoluble in water; after extraction, a mixed solution consisting of an acetone aqueous solution and a 2-MPA solution exits the extraction tower (10) from an outlet C at the bottom of the extraction tower (10) and enters a phase separator (11) through an inlet A at the middle of the phase separator (11); in the phase separator (11), the acetone aqueous solution and the 2-MPA solution are phase-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 upper outlet B of the phase separator (11) as a target product to be separated from the boundary zone; (4) Second pre-fractionation section: the acetone aqueous solution from the azeotropic extraction section enters the acetone aqueous solution extraction tank (12), and is sent to the acetone aqueous solution heater (14) through the acetone aqueous solution feed pump (13). After being heated, the acetone aqueous solution enters the second pre-fractionation section of the distillation tower (2) from the acetone aqueous solution inlet F of the second pre-fractionation section of the distillation tower (2) for pre-fractionation. After the pre-fractionation, the acetone aqueous solution is initially fractionated; the aqueous solution flows downward and is firstly distilled in the second pre-fractionation section stripping layer (2-14), and then goes to the stripping section; the acetone gas flows upward and is firstly distilled in the second pre-fractionation section stripping layer (2-13), and then goes to the acetone stripping section; (5) Acetone distillation section: The acetone gas from the distillation layer (2-13) of the second pre-fractionation section is distilled in the distillation layer (2-15) of the acetone distillation section, and heat and mass transfer is carried out with the acetone solution refluxed from the acetone reflux port D on the upper side of the distillation tower (2). The acetone solution flows downward and enters the second pre-fractionation section. The acetone gas after distillation leaves the distillation tower (2) from the acetone outlet B at the top of the distillation tower (2) and is condensed into liquid by the acetone condenser (15) and then enters the acetone reflux tank. (16), a portion of the acetone solution in the acetone reflux tank (16) is discharged from the reflux liquid outlet B of the acetone reflux tank (16) as reflux liquid and enters the acetone distillation section of the distillation tower (2) from the acetone reflux port D on the upper side of the distillation tower (2) through the acetone reflux pump (17), and another portion of the acetone solution in the acetone reflux tank (16) is discharged from the acetone outlet C of the acetone reflux tank (16) as the target product II to the MIBK synthesis system for reuse, and the ratio of the two portions of the 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, and heat and mass transfer is carried out with the gas phase refluxed from the lower reflux port G of the distillation tower (2). The acetone gas after stripping flows upward and enters the second pre-fractionation section, and the mixed liquid of MIBK, heavy components and water flows downward. A part of the mixed liquid is sent to the reboiler (18) from the bottom liquid outlet H of the distillation tower (2), and the mixed liquid is heated in the reboiler (18). The acetone in the mixed liquid is heated and evaporated into gas as the gas phase and enters the stripping section from the lower reflux port G of the distillation tower (2). Another part of the mixed liquid is sent from the bottom liquid outlet J of the distillation tower (2) as the target product three, i.e., MIBK solution, and the MIBK product is distilled by the MIBK distillation system in the deboundary zone.

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