Rectification equipment for rectifying heavy components in MIBK tower bottoms

Abstract

The invention provides rectification equipment for rectifying heavy components in MIBK (methyl isobutyl ketone) tower bottoms, and belongs to the technical field of chemical rectification. The rectifying equipment comprises a rectifying tower with a cylindrical barrel structure, and a vertical partition plate is arranged in the rectifying tower and divides the rectifying tower into a pre-fractionating section, a rectifying section, a stripping section and a middle discharging section. By adopting the rectification equipment, tower bottoms from an MIBK rectification system can be rectified and separated, and a target product 1-MIBK is recovered at the rectification section of the rectification tower; a target product 2-DIBK (the chemical name is diisobutyl ketone, hereinafter referred to as DIBK) is recycled at a middle discharging section of the rectifying tower; and recovering the target product 3-C9 saturated alkane by a reboiler. By utilizing the rectification equipment, the product quality can be improved, 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 device for distilling heavy components of a MIBK tower bottom liquid. 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] DIBK, chemical name diisobutyl ketone, is an organic compound with the chemical formula C9H 18 O is used as solvent resin, has good solvent properties, does not corrode the substrate, has good performance in plastic paint, and is mainly used in vacuum electroplating coatings, plastic paints, leather finishing and other industries.

[0004] C9 saturated alkanes have stable chemical properties and are widely used in practical applications, including chemical raw materials, fuels, lubricant additives, and biomedical materials.

[0005] The heavy component of the bottom liquid from the MIBK distillation system contains MIBK, DIBK and C9 saturated alkanes, of which the mass concentration of MIBK is about 14%, the mass concentration of DIBK is about 62%, and the rest is C9 saturated alkanes. The above organic substances need to be distilled, separated and recovered. In the existing distillation production of the heavy component of the bottom liquid of the MIBK distillation system, a two-step distillation process is usually adopted. Step 1: The heavy component of the bottom liquid from the MIBK distillation system is distilled to recover MIBK through the de-MIBK tower; Step 2: The bottom liquid produced in step 1 is sent to the DIBK product tower for distillation to separate the DIBK product, and the bottom liquid is C9 saturated alkanes. The above de-MIBK, distillation separation of DIBK and C9 saturated alkanes are distilled, 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 distillation separation energy consumption accounts for 95% of it.

[0006] Therefore, it is necessary to improve the existing equipment for distilling the heavy fraction of the MIBK tower bottom liquid, and it is urgent to provide a distillation equipment for distilling the heavy fraction of the MIBK tower bottom liquid with a short process, small footprint, low investment and low energy consumption. Summary of the invention

[0007] The object of the present invention is to provide a distillation device for distilling heavy components of MIBK tower bottom liquid, wherein the heavy components of the tower bottom liquid from the MIBK distillation system are distilled and separated in a partition plate distillation tower. The partition plate distillation tower is different from the conventional distillation tower in that it not only has a distillation section and a stripping section, but also has a pre-fractionation section and an intermediate discharge section. The distillation section of the distillation tower recovers a target product 1, namely, MIBK; the intermediate discharge section of the distillation tower recovers a target product 2, namely, DIBK; and the reboiler recovers a target product 3, namely, C9 saturated alkanes.

[0008] By adopting the above distillation equipment, only one set of distillation equipment is needed to recover the target product. It is a distillation equipment for distilling the heavy components of the MIBK tower bottom liquid with a short process, small footprint, low investment and low energy consumption. The present invention aims to save energy and reduce consumption, reduce investment in production equipment, reduce carbon emissions and protect the environment.

[0009] The purpose of the present invention can be achieved through the following technical solutions:

[0010] A distillation device for distilling a heavy component of a MIBK tower bottom liquid comprises a distillation tower and a reboiler; a vertical partition plate is arranged in the distillation tower, the vertical partition plate is located in the middle of the distillation tower, and a plurality of liquid distributors are installed in the distillation tower; a distillation section is arranged in the upper part of the distillation tower, a MIBK gas outlet A is arranged at the top of the distillation section, and a MIBK solution reflux port B is arranged on the side of the distillation section; a pre-fractionation section and an intermediate discharge section are arranged on both sides of the vertical partition plate in the middle of the distillation tower, a MIBK tower bottom liquid heavy component feed port C is arranged in the pre-fractionation section, and a MIBK solution outlet D is arranged in the intermediate discharge section; a stripping section is arranged in the lower part of the distillation tower, and a discharge reflux port E is arranged at the bottom of the stripping section; and both the pre-fractionation section and the intermediate discharge section are provided with a stripping layer and a distillation layer.

[0011] As a preferred embodiment of the present invention, a heating coil is provided inside the reboiler; a steam inlet F is provided on the side of the reboiler, a condensate outlet G is provided at the lower end of the steam inlet F, and both ends of the heating coil are connected to the steam inlet F and the condensate outlet G respectively; a C9 saturated alkane solution outlet H is provided at the bottom of the reboiler.

[0012] As a preferred embodiment of the present invention, a second distillation layer is provided in the middle of the distillation section, a tube-type liquid distributor is horizontally installed at the MIBK solution reflux port B above the second distillation layer, and a second liquid distributor is horizontally installed below the second distillation layer.

[0013] As a preferred embodiment of the present invention, a first distillation layer is provided at the upper part of the pre-fractionation section, a first liquid distributor is horizontally installed below the first distillation layer, a first stripping layer is provided below the first liquid distributor, and a raw material feed pipe is horizontally installed at the feed port C of the heavy component of the MIBK tower bottom liquid between the first distillation layer and the first liquid distributor.

[0014] As a preferred embodiment of the present invention, a third distillation layer is provided at the upper part of the intermediate discharging section, a fourth liquid distributor is horizontally installed below the third distillation layer, a third stripping layer is provided below the fourth liquid distributor, and the DIBK solution outlet D is located between the third distillation layer and the fourth liquid distributor.

[0015] As a preferred embodiment of the present invention, a third liquid distributor is provided at the upper portion of the stripping section, and a second stripping layer is provided below the third liquid distributor.

[0016] As a preferred embodiment of the present invention, the top of the vertical partition plate is at the same height as or higher than the top of the pre-fractionation section and the intermediate discharging section distillation layer, and the bottom end is at the same height as or lower than the bottom end of the pre-fractionation section and the intermediate discharging section distillation layer.

[0017] As a preferred embodiment of the present invention, the ratio of the horizontal cross-sectional area between the pre-fractionation section and the rectifying layer of the middle discharge section and / or the horizontal cross-sectional area between the pre-fractionation section and the stripping layer of the middle discharge section is 1:10 to 10:1.

[0018] As a preferred embodiment of the present invention, the rectification layer and / or stripping layer is a packing layer and has a height of 2 to 12 meters.

[0019] As a preferred embodiment of the present invention, the distillation tower and / or reboiler is a vertical cylindrical shell.

[0020] In some specific technical solutions, the contents are as follows:

[0021] The raw material from the MIBK distillation system, the tower bottom liquid heavy component pipeline, is connected to the MIBK tower bottom liquid heavy component tank, the distillation tower feed pump, the preheater, and the MIBK tower bottom liquid heavy component feed port C on the middle side of the distillation tower in sequence. The MIBK gas outlet A at the top of the distillation tower is connected to the top inlet A of the reflux tank through a condenser, the lower side outlet B of the reflux tank is connected to the MIBK solution reflux port B on the upper side of the distillation tower through a reflux pump, and the lower outlet C of the reflux tank is connected to the target product 1 in the deboundary area, the MIBK pipeline.

[0022] In the above-mentioned distillation equipment: the DIBK solution outlet D on the side of the middle part of the distillation tower is connected to the target product 2 in the deboundary area - DIBK pipeline.

[0023] In the above distillation equipment: the C9 saturated alkane solution outlet H at the bottom of the reboiler is connected to the target product 3 in the deboundary zone - C9 saturated alkane pipeline.

[0024] In the above distillation equipment: the distillation layer of the pre-fractionation section, the distillation layer of the intermediate discharging section, the retention layer of the pre-fractionation section, and the retention layer of the intermediate discharging section are all packing layers with a height of 2 to 12 meters; the distillation layer of the distillation section is a packing layer with a height of 2 to 12 meters, and the stripping layer of the stripping section is a packing layer with a height of 2 to 12 meters.

[0025] The method for realizing the distillation of the heavy fraction of the MIBK tower bottom liquid by using the above distillation equipment includes the following steps:

[0026] (1) Pretreatment section: The raw material from the MIBK distillation system, the bottom liquid heavy component, enters the MIBK bottom liquid heavy component tank from the top inlet A of the MIBK bottom liquid heavy component tank. The bottom liquid heavy component in the MIBK bottom liquid heavy component tank enters the preheater from the lower outlet B of the MIBK bottom liquid heavy component tank through the distillation tower feed pump. After being heated in the preheater, the bottom liquid heavy component leaves the preheater and goes to the pre-fractionation section.

[0027] (2) Pre-fractionation section: The heavy components of the MIBK tower bottom liquid from the pre-treatment section enter the distillation tower from the MIBK tower bottom liquid heavy component feed port C on the side of the middle of the distillation tower for pre-fractionation. After pre-fractionation, the heavy components of the MIBK tower bottom liquid are preliminarily fractionated. The mixed gas of MIBK and DIBK flows upward and is first distilled in the distillation layer of the pre-fractionation section, and then goes to the distillation section; the mixed liquid of DIBK and C9 saturated alkanes flows downward and is first retained in the stripping layer of the pre-fractionation section, and then goes to the stripping section.

[0028] (3) Distillation section: The mixed gas of MIBK and DIBK from the pre-fractionation section of the distillation tower is distilled in the distillation layer of the distillation section, and heat and mass transfer is carried out with the MIBK solution refluxed from the MIBK solution reflux port B on the upper side of the distillation tower. The DIBK solution flows downward into the middle discharge section, and the distilled MIBK gas flows upward, exits the distillation section of the distillation tower from the MIBK gas outlet A at the top of the distillation tower, is condensed into liquid through the condenser, and then enters the reflux tank. A part of the MIBK in the reflux tank is used as reflux liquid to enter the distillation section of the distillation tower from the lower side outlet B of the reflux tank through the reflux pump and the MIBK solution reflux port B on the upper side of the distillation tower; another part of the MIBK in the reflux tank is used as the target product 1 to go to the boundary area from the lower side outlet C of the reflux tank.

[0029] (4) Distillation section: The mixed liquid of DIBK and C9 saturated alkane from the pre-fractionation section of the distillation tower is distilled in the stripping layer of the stripping section, and heat and mass transfer is carried out with the gas phase refluxed from the discharge reflux port E at the bottom of the distillation tower. The DIBK gas after distillation flows upward and enters the intermediate discharge section, and the C9 saturated alkane solution flows downward and exits the distillation section of the distillation tower from the discharge reflux port E at the bottom of the distillation tower and enters the reboiler. In the reboiler, the C9 saturated alkane solution is heated by the heating coil, and the DIBK in the C9 saturated alkane solution is heated and evaporated into gas as the gas phase and exits the reboiler from the discharge reflux port E at the bottom of the distillation tower and enters the stripping section of the distillation tower; the C9 saturated alkane solution at the bottom of the reboiler exits the reboiler from the C9 saturated alkane solution outlet H at the bottom of the reboiler as the target product 3 de-boundary zone.

[0030] (5) Intermediate discharging section: The DIBK solution flowing downward from the rectifying section of the distillation tower into the intermediate discharging section of the distillation tower is distilled in the rectifying layer of the intermediate discharging section, and the DIBK gas flowing upward from the stripping section of the distillation tower into the intermediate discharging section of the distillation tower is retained in the stripping layer of the intermediate discharging section. The DIBK is purified in the intermediate discharging section, and the purified DIBK is taken as the target product 2 from the DIBK solution outlet D of the intermediate discharging section of the distillation tower to the boundary area.

[0031] In the above method, the raw material from the MIBK distillation system contains MIBK at a mass concentration of ≤20%, DIBK at a mass concentration of ≥55%, and the rest is C9 saturated alkanes.

[0032] Beneficial effects of the present invention:

[0033] The heavy components of the bottom liquid from the MIBK distillation system contain MIBK, DIBK and C9 saturated alkanes, which need to be separated to make the best use of them. The present invention provides a distillation device for distilling the heavy components of the MIBK bottom liquid. The distillation device can effectively separate the heavy components of the MIBK bottom liquid, wherein about 140 kg of MIBK, about 620 kg of DIBK and about 240 kg of C9 saturated alkanes can be obtained by distilling 1 ton of the heavy components of the MIBK bottom liquid.

[0034] The distillation tower of the present invention adopts a partition plate distillation tower to replace the MIBK removal tower and the DIBK product tower, combines the two distillation towers into one, and saves a condenser and a reboiler, saving about 30% of the investment in distillation equipment; DIBK appears at the top and bottom of the tower at the same time, and the composition of the raw materials entering the partition plate distillation tower can be well matched with the composition on the pre-fractionation section liquid distributor, reducing the mixing effect at the liquid distributor, that is, reducing the mixing effect caused by the different compositions of the feed and the liquid distributor, meeting the requirements of the optimal feed liquid distributor, and improving the thermodynamic efficiency. Since the heat of the partition plate distillation tower is repeatedly recycled in the same tower, the distillation energy consumption is also saved, and the energy consumption saved is about 30%.

[0035] The reboiler is vertical and has heating coils along the inner wall, so that the reboiler is heated evenly as a whole, the tower bottom liquid can easily reach a higher temperature, and there is no dead angle for the flow of fluid in the bottom.

[0036] The above distillation equipment is used to obtain target product 1 - MIBK, target product 2 - DIBK and target product 3 - C9 saturated alkane. It is a distillation equipment for distilling the heavy component of MIBK tower bottom liquid, which is safe, environmentally friendly, has a high yield of target products and low energy consumption. The present invention aims to save energy and reduce consumption, reduce carbon emissions of production equipment and protect the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The working section division diagram of the distillation equipment in the present invention is

[0038] Figure 2 The distillation equipment diagram of the present invention

[0039] Figure 3 The schematic diagram of the process flow in the present invention is

[0040] Among them, the MIBK tower bottom liquid re-constituent tank 1, the distillation tower feed pump 2, the preheater 3, the distillation tower 4, the partition plate 5, the condenser 6, the reflux tank 7, the reflux pump 8, the reboiler 9, and the heating coil 10; the raw material feed pipe 4-1, the first liquid distributor 4-2, the first distillation layer 4-3, the first retention layer 4-4, the second distillation layer 4-5, the second liquid distributor 4-6, the calandria liquid distributor 4-7, the second distillation layer 4-8, the third liquid distributor 4-9, the third distillation layer 4-10, the third retention layer 4-11, and the fourth liquid distributor 4-12. DETAILED DESCRIPTION

[0041] 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.

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0043] like Figure 1 , 2The distillation equipment shown is for distilling the heavy fraction of the bottom liquid of a MIBK tower. The distillation equipment can distill and separate the bottom liquid from the MIBK distillation system. The distillation section of the distillation tower recovers the target product 1 - MIBK, the middle discharge section of the distillation tower recovers the target product 2 - DIBK, and the reboiler recovers the target product 3 - C9 saturated alkanes. The distillation equipment comprises a distillation tower 4 and a reboiler 9; a vertical partition plate 5 is arranged in the distillation tower 4, the vertical partition plate 5 is located in the middle of the distillation tower 4, and a plurality of liquid distributors are installed in the distillation tower 4; a distillation section is arranged in the upper part of the distillation tower 4, a MIBK gas outlet A is arranged at the top of the distillation section, and a MIBK solution reflux port B is arranged on the side of the distillation section; a pre-fractionation section and an intermediate discharge section are arranged on both sides of the vertical partition plate 5 in the middle of the distillation tower 4, the pre-fractionation section is provided with a MIBK tower bottom liquid heavy component feed port C, and the intermediate discharge section is provided with a DIBK solution outlet D; a stripping section is arranged in the lower part of the distillation tower 4, and a discharge reflux port E is arranged at the bottom of the stripping section; the pre-fractionation section and the intermediate discharge section are both provided with a stripping layer and a distillation layer.

[0044] In the above-mentioned distillation equipment: the distillation tower 4 and the reboiler 9 are both vertical cylindrical barrels.

[0045] In the above-mentioned distillation equipment: a heating coil 10 is provided inside the reboiler 9; a steam inlet F is provided on the side of the reboiler 9, a condensate outlet G is provided at the lower end of the steam inlet F, and both ends of the heating coil 10 are connected to the steam inlet F and the condensate outlet G respectively; a C9 saturated alkane solution outlet H is provided at the bottom of the reboiler 9.

[0046] In the above distillation equipment: a second distillation layer 4-5 is provided in the middle of the distillation section, a tube-type liquid distributor 4-7 is horizontally installed at the MIBK solution reflux port B above the second distillation layer 4-5, and a second liquid distributor 4-6 is horizontally installed below the second distillation layer 4-5.

[0047] In the above-mentioned distillation equipment: a first distillation layer 4-3 is provided on the upper part of the pre-fractionation section, a first liquid distributor 4-2 is horizontally installed below the first distillation layer 4-3, a first stripping layer 4-4 is provided below the first liquid distributor 4-2, and a raw material feed pipe 4-1 is horizontally installed at the feed port C of the heavy component of the MIBK tower bottom liquid between the first distillation layer 4-3 and the first liquid distributor 4-2.

[0048] In the above-mentioned distillation equipment: a third distillation layer 4-10 is provided on the upper part of the intermediate discharging section, a fourth liquid distributor 4-12 is horizontally installed below the third distillation layer 4-10, a third stripping layer 4-11 is provided below the fourth liquid distributor 4-12, and the DIBK solution outlet D is located between the third distillation layer 4-10 and the fourth liquid distributor 4-12.

[0049] In the above distillation equipment: a third liquid distributor 4-9 is provided on the upper part of the stripping section, and a second stripping layer 4-8 is provided below the third liquid distributor 4-9.

[0050] In the above distillation equipment: the top of the vertical partition plate 5 is not lower than the top of the first distillation layer 4-3 and the top of the third distillation layer 4-10, and the bottom is not higher than the bottom of the first distillation layer 4-4 and the bottom of the third distillation layer 4-11.

[0051] In the above distillation equipment: the ratio of the horizontal cross-sectional areas of the first distillation layer 4-3 and the third distillation layer 4-10 is 1:1; the ratio of the horizontal cross-sectional areas of the first stripping layer 4-4 and the third stripping layer 4-11 is 1:1.

[0052] In the above distillation equipment: the first distillation layer 4-3, the third distillation layer 4-10, the first retention layer 4-4, and the third retention layer 4-11 are all packing layers and have a height of 2.5 meters.

[0053] The second rectification layer 4-5 is a packing layer with a height of 2.5 meters, and the second stripping layer 4-8 is a packing layer with a height of 2.5 meters.

[0054] like Figure 3 The distillation equipment further comprises a MIBK tower bottom liquid heavy component tank 1 arranged outside the distillation tower 4 and the reboiler 9, a distillation tower feed pump 2, a preheater 3, a condenser 6, a reflux tank 7, and a reflux pump 8.

[0055] In some more specific embodiments, the content is as follows:

[0056] The raw material from the MIBK distillation system, the tower bottom liquid heavy component pipeline, is sequentially connected to the MIBK tower bottom liquid heavy component tank 1, the distillation tower feed pump 2, the preheater 3, and the MIBK tower bottom liquid heavy component feed port C on the middle side of the distillation tower 4. The MIBK gas outlet A at the top of the distillation tower 4 is connected to the top inlet A of the reflux tank 7 through the condenser 6, the lower side outlet B of the reflux tank 7 is connected to the MIBK solution reflux port B on the upper side of the distillation tower 4 through the reflux pump 8, and the lower outlet C of the reflux tank 7 is connected to the target product 1 of the deboundary area, the MIBK pipeline.

[0057] The DIBK solution outlet D on the side of the middle part of the distillation tower 4 is connected to the target product 2 - DIBK pipeline of the deboundary area.

[0058] The C9 saturated alkane solution outlet H at the bottom of the reboiler 9 is connected to the target product 3 of the deboundary zone - C9 saturated alkane pipeline.

[0059] The method for realizing the distillation of the heavy fraction of the MIBK tower bottom liquid by using the above distillation equipment includes the following steps:

[0060] (1) Pretreatment section: The raw material from the MIBK distillation system, namely, the bottom liquid heavy component (temperature 45°C, MIBK content 14%, DIBK content 62%, C9 saturated alkane content 24%) enters the MIBK bottom liquid heavy component tank 1 from the top inlet A of the MIBK bottom liquid heavy component tank 1. The bottom liquid heavy component in the MIBK bottom liquid heavy component tank 1 enters the preheater 3 from the lower outlet B of the MIBK bottom liquid heavy component tank 1 through the distillation tower feed pump 2. The bottom liquid heavy component is heated in the preheater 3 (temperature 165°C) and then exits the preheater 3 to the pre-fractionation section.

[0061] (2) Pre-fractionation section: The heavy components of the MIBK tower bottom liquid from the pre-treatment section enter the distillation tower 4 through the feed port C of the MIBK tower bottom liquid heavy components on the side of the middle part of the distillation tower 4 through the raw material feed pipe 4-1 for pre-fractionation. After the pre-fractionation, the heavy components of the MIBK tower bottom liquid are preliminarily fractionated. The mixed gas of MIBK and DIBK flows upward and is first distilled in the first distillation layer 4-3, and then goes to the distillation section; the mixed liquid of DIBK and C9 saturated alkanes flows downward and is first retained in the first stripping layer 4-4, and then goes to the stripping section.

[0062] (3) Distillation section: The mixed gas of MIBK and DIBK from the pre-fractionation section of the distillation tower 4 is distilled in the distillation layer 4-5 of the distillation section, and heat and mass transfer is carried out with the MIBK solution (temperature 116.5° C., MIBK mass concentration 99%) refluxed from the MIBK solution reflux port B on the upper side of the distillation tower 4. The DIBK solution flows downward into the middle discharge section, and the distilled MIBK gas (temperature 116.5° C., MIBK mass concentration 99%) flows upward, exits the distillation section of the distillation tower from the MIBK gas outlet A at the top of the distillation tower 4, is condensed into liquid (temperature 116.5° C.) by the condenser 6, and then enters the reflux tank 7. A part of the MIBK in the reflux tank 7 is used as reflux liquid and is discharged from the lower side outlet B of the reflux tank 7 through the reflux pump 8, through the MIBK solution reflux port B on the upper side of the distillation tower 4, and into the distillation section of the distillation tower 4 through the calandria liquid distributor 4-7; another part of the MIBK in the reflux tank 7 (temperature 116.5° C., MIBK mass concentration 99%) is used as the target product 1 and is discharged from the lower side outlet C of the reflux tank 7 to the boundary area.

[0063] (4) Distillation section: The mixed liquid of DIBK and C9 saturated alkane from the pre-fractionation section of the distillation tower 4 is distilled in the second distillation layer 4-8, and heat and mass transfer is carried out with the gas phase (temperature 198° C.) refluxed from the bottom discharge reflux port E of the distillation tower 4. The distilled DIBK gas flows upward into the middle discharge section, and the C9 saturated alkane solution flows downward, exits the distillation section of the distillation tower 4 from the bottom discharge reflux port E of the distillation tower 4 and enters the reboiler 9. In the reboiler 9, the C9 saturated alkane solution is heated and heated to 198° C. The alkane solution is heated by the heating coil, and the DIBK in the C9 saturated alkane solution (temperature 198°C) is heated and evaporated into gas (temperature 198°C) as the gas phase from the bottom discharge reflux port E of the distillation tower 4 to the reboiler 9 and enter the distillation section of the distillation tower 4; the C9 saturated alkane solution at the bottom of the reboiler 4 (temperature 198°C, containing C9 saturated alkane mass concentration of 99%) is discharged from the reboiler 9 from the C9 saturated alkane solution outlet H at the bottom of the reboiler 9 as the target product 3 de-boundary zone.

[0064] (5) Intermediate discharging section: The DIBK solution flowing downward from the rectifying section of the rectifying tower 4 into the intermediate discharging section of the rectifying tower is rectified in the third rectifying layer 4-10, and the DIBK gas flowing upward from the stripping section of the rectifying tower into the intermediate discharging section of the rectifying tower 4 is stripped in the third stripping layer 4-11. The DIBK is purified in the intermediate discharging section, and the purified DIBK (containing a DIBK mass concentration of 99%) is discharged as the target product 2 from the DIBK solution outlet D of the intermediate discharging section of the rectifying tower 4 to the boundary area.

[0065] The results of the operation of the present invention are shown in Table 1.

[0066] Table 1 Performance evaluation results of 1000 tons / year MIBK bottom liquid heavy fraction distillation unit

[0067] Table 1 Performance evaluation results of 1000 tons / year MIBK bottom liquid heavy fraction distillation unit

[0068]

Claims

1. A distillation device for distilling heavy components of MIBK tower bottom liquid, characterized in that: The distillation equipment comprises a distillation tower (4) and a reboiler (9); a vertical partition plate (5) is arranged in the distillation tower (4), the vertical partition plate (5) is located in the middle of the distillation tower (4), and a plurality of liquid distributors are installed in the distillation tower (4); a distillation section is arranged in the upper part of the distillation tower (4), a MIBK gas outlet A is arranged at the top of the distillation section, and a MIBK solution reflux port B is arranged on the side of the distillation section; a pre-fractionation section and an intermediate discharge section are arranged on both sides of the vertical partition plate (5) in the middle of the distillation tower (4), the pre-fractionation section is provided with a MIBK tower bottom liquid heavy component feed port C, and the intermediate discharge section is provided with a DIBK solution outlet D; a stripping section is arranged in the lower part of the distillation tower (4), and a discharge reflux port E is arranged at the bottom of the stripping section; the pre-fractionation section and the intermediate discharge section are both provided with a stripping layer and a distillation layer.

2. The distillation equipment according to claim 1, characterized in that: The reboiler (9) is provided with a heating coil (10) inside; a steam inlet F is provided on the side of the reboiler (9), a condensate outlet G is provided at the lower end of the steam inlet F, and both ends of the heating coil (10) are connected to the steam inlet F and the condensate outlet G respectively; and a C9 saturated alkane solution outlet H is provided at the bottom of the reboiler (9).

3. The distillation equipment according to claim 1, characterized in that: A second distillation layer (4-5) is provided in the middle of the distillation section, a tube-type liquid distributor (4-7) is horizontally installed at a MIBK solution reflux port B above the second distillation layer (4-5), and a second liquid distributor (4-6) is horizontally installed below the second distillation layer (4-5).

4. The distillation equipment according to claim 1, characterized in that: A first distillation layer (4-3) is provided at the upper part of the pre-fractionation section, a first liquid distributor (4-2) is horizontally installed below the first distillation layer (4-3), a first stripping layer (4-4) is provided below the first liquid distributor (4-2), and a raw material feed pipe (4-1) is horizontally installed at a feed port C of the heavy component of the MIBK tower bottom liquid between the first distillation layer (4-3) and the first liquid distributor (4-2).

5. The distillation equipment according to claim 1, characterized in that: A third distillation layer (4-10) is arranged at the upper part of the middle discharging section, a fourth liquid distributor (4-12) is horizontally installed below the third distillation layer (4-10), a third stripping layer (4-11) is arranged below the fourth liquid distributor (4-12), and a DIBK solution outlet D is located between the third distillation layer (4-10) and the fourth liquid distributor (4-12).

6. The distillation equipment according to claim 1, characterized in that: A third liquid distributor (4-9) is provided at the upper part of the stripping section, and a second stripping layer (4-8) is provided below the third liquid distributor (4-9).

7. The distillation equipment according to claim 1, characterized in that: The top of the vertical partition plate (5) is at the same height as or higher than the top of the pre-fractionation section and the middle discharge section distillation layer, and the bottom is at the same height as or lower than the bottom of the pre-fractionation section and the middle discharge section distillation layer.

8. The distillation equipment according to claim 7, characterized in that: The ratio of the horizontal cross-sectional area between the pre-fractionation section and the rectifying layer of the middle discharging section and / or the horizontal cross-sectional area between the pre-fractionation section and the stripping layer of the middle discharging section is 1:10 to 10:

1.

9. The distillation equipment according to claim 1, characterized in that: The rectification layer and / or stripping layer is a packing layer and has a height of 2 to 12 meters.

10. The distillation equipment according to claim 1, characterized in that: The distillation tower (4) and / or the reboiler (9) is a vertical cylindrical shell.

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