Dehydrating tower, rectifying device and system for synthesizing MIBK (methyl isobutyl ketone)

Abstract

The invention relates to a dehydrating tower which comprises a dehydrating tower body, a dehydrating tower condenser arranged at the top of the dehydrating tower body, and a liquid collecting tray horizontally arranged in the upper part of the dehydrating tower body, a riser is upwards arranged on the liquid collecting tray and is a through pipe, a baffle is arranged at the top of the riser, and the bottom of the riser is communicated with the liquid collecting tray. A water phase pump and an oil phase pump in the prior art can be omitted by arranging a dehydrating tower condenser at the top of the dehydrating tower and arranging a liquid collecting tray in the upper part of the dehydrating tower. According to the dehydrating tower, a plurality of devices are organically combined and functionally combined, so that on one hand, the occupied area and investment are saved, and the energy consumption of the device is reduced; and on the other hand, the limitation of a pump in the prior art is broken through, the flow is increased, the chromatography effect is further enhanced, the product quality and the production efficiency are improved, the control is more stable, and the operation is more convenient. In addition, the invention also provides a dehydration method of the dehydration tower, a rectification device comprising the dehydration tower, and a system and a method for synthesizing MIBK.

Description

[0001] Field

[0002] The invention relates to the technical field of synthesizing MIBK (methyl isobutyl ketone), in particular to a dehydration tower; meanwhile, the invention also relates to a MIBK distillation device comprising the dehydration tower and a system for synthesizing MIBK. Background Art

[0003] MIBK has become the main auxiliary solvent for high-end coatings because of its good solubility, excellent miscibility with other solvents and suitable boiling point; it has stable chemical properties and can meet the special requirements of high-end coatings such as solid components, volatilization rate, leveling, coating strength, and appearance.

[0004] In the prior art, acetone and hydrogen are reacted in a fixed bed reactor under the action of a catalyst to generate MIBK in one step. The raw materials hydrogen and acetone are preheated first, and then reacted in a fixed bed reactor. The product after the reaction and the circulating gas phase are condensed, separated at low temperature and enter the first distillation tower, the unreacted acetone is separated in the second distillation tower, the light component water is separated in the third distillation tower, and the pure MIBK product is obtained at the top of the fourth distillation tower. The dehydration tower bottom contains a high condensate. The production process has the advantages of short process, low investment, high acetone conversion rate, high MIBK selectivity, low raw material consumption and energy consumption.

[0005] Wherein, the third distillation tower is a dehydration tower (such as Figure 1 As shown), water and isopropanol are removed from the top of the tower. The conventional process is as follows: the material at the top of the dehydration tower enters the dehydration tower condenser, condenses into a liquid phase and enters the dehydration tower reflux tank. The reflux tank is used as a reflux buffer while also performing chromatography of the oil phase and the water phase. The water phase is pumped to the wastewater tower, and the oil phase is pressurized by a pump and then divided into three streams, one of which returns to the tower for reflux, one is sent to the acetone tower, and one is sent to the light component tower. The one-step synthesis process of MIBK requires a relatively small flow rate. Specifically, taking a 15,000-ton device as an example, the flow rates of the oil phase pump at the top of the dehydration tower and the water phase pump at the top of the dehydration tower are both less than 1m 3 / h, when the flow rate is small, on the one hand, the pump efficiency is low, resulting in low production efficiency; on the other hand, it will affect the chromatography effect. Summary of the invention

[0006] In order to solve the problems in the prior art, the present invention provides a dehydration tower that organically combines and integrates multiple devices, which, on the one hand, saves space and investment and reduces energy consumption of the device; on the other hand, it breaks through the limitations of the pump in the prior art, increases the flow rate, further enhances the chromatography effect, improves product quality and production efficiency, and makes the control more stable and more convenient to operate.

[0007] One of the objects of the present invention is to provide a dehydration tower, which includes a dehydration tower body, a dehydration tower condenser arranged on the top of the dehydration tower body, and a liquid collecting pan horizontally arranged in the upper part of the dehydration tower body; an air riser is arranged upward on the liquid collecting pan, and the air riser is a through pipe, a baffle is arranged on the top, and the bottom is connected to the liquid collecting pan.

[0008] In a preferred embodiment of the present invention,

[0009] The inner diameter of the riser is 1 / 8 to 3 / 8 of the inner diameter of the dehydration tower body; and / or

[0010] The height of the riser is 1 / 50 to 1 / 10 of the height of the dehydration tower body, preferably 1 / 25 to 2 / 25.

[0011] In a preferred embodiment of the present invention,

[0012] The distance between the top surface of the riser and the dehydration tower condenser is 0.3 to 2 m, preferably 0.4 to 1 m; and / or

[0013] The condensation temperature of the dehydration tower condenser is 40-82°C, preferably 40-50°C.

[0014] In a preferred embodiment of the present invention,

[0015] The edge of the liquid collecting tray is fixedly connected to the inner wall of the dehydration tower body; and / or

[0016] A baffle is connected above the riser, and the baffle is connected to the liquid collecting tray through at least two supporting members; the orthographic projection of the baffle on the horizontal plane covers the orthographic projection of the riser on the horizontal plane;

[0017] Preferably, the baffle is any one of an umbrella shape, a semicircular shape, a triangle shape, and a square shape;

[0018] More preferably, the baffle is umbrella-shaped or semicircular.

[0019] In a preferred embodiment of the present invention,

[0020] The dehydration tower body is provided with a gas phase feed inlet in the middle and a tower bottom outlet at the bottom; and / or

[0021] The oil phase extraction and water phase extraction are arranged on both sides of the dehydration tower body, both of which are higher than the liquid collecting tray, and the oil phase extraction position is higher than the water phase extraction position.

[0022] In a preferred embodiment of the present invention,

[0023] A water level meter is arranged on the pipeline for producing the water phase; and / or

[0024] An oil phase level meter is arranged on the oil phase production pipeline; and / or

[0025] The oil phase production pipeline is connected to the oil phase separation tower and the light component storage tank respectively, and is also connected to the reflux pipeline to reflux part of the produced oil phase into the dehydration tower body. The reflux pipeline inlet is arranged below the liquid collection tray at the position of the dehydration tower body.

[0026] The second object of the present invention is to provide a dehydration method of the dehydration tower described in the first object of the present invention, characterized in that it comprises the following steps:

[0027] The reaction gas phase mixture enters the dehydration tower body through the gas phase feed port of the dehydration tower, and the gas phase mixture moves upward, passes through the gas riser in the middle of the liquid collecting plate, enters the dehydration tower condenser, and is condensed into a liquid phase, and then falls into the liquid collecting plate under the action of gravity, and is collected on the liquid collecting plate and chromatographed;

[0028] Preferably, the condensation temperature of the dehydration tower condenser is 40-82° C., more preferably 40-50° C.; and / or the pressure drop of the dehydration tower condenser is not greater than 20 kPa.

[0029] In a preferred embodiment of the present invention,

[0030] The condensate liquid phase collected on the liquid collection tray forms an oil phase at the top and a water phase at the bottom after standing; preferably,

[0031] The water phase is produced by controlling the water phase boundary level meter; and / or

[0032] The oil phase is produced by the oil phase level meter and is divided into three routes: one route is for oil phase separation, another route is for light component storage tank, and the rest is returned to the dehydration tower body.

[0033] In a preferred embodiment of the present invention,

[0034] The condensate collected on the liquid collection tray is allowed to stand for 10 to 250 minutes, preferably 30 to 180 minutes; and / or

[0035] 10-20% of the oil phase produced is discharged to the oil phase separation tower, 5-20% is discharged to the light component storage tank, and the remaining oil phase is refluxed through the reflux pipeline.

[0036] The third object of the present invention is to provide a distillation device comprising the dehydration tower described in one of the objects of the present invention. Preferably, the distillation device comprises a first distillation tower, a second distillation tower, the dehydration tower and a fourth distillation tower connected in sequence.

[0037] The fourth object of the present invention is to provide a system for synthesizing MIBK comprising the distillation device described in the third object of the present invention. Specifically, the system for synthesizing MIBK includes a reactor, a separator and a distillation device connected in sequence.

[0038] In a preferred embodiment of the present invention,

[0039] The reactor includes, from bottom to top, a first tube sheet, a heat exchange tube bundle, a second tube sheet, a gas-liquid distributor, a feed nozzle disposed on the side wall of the reactor, and a hydrogen feed pipe disposed on the top of the reactor;

[0040] Preferably, the gas-liquid distributor comprises a distribution plate, a lower liquid hole opened on the distribution plate, and a downcomer provided on the distribution plate and extending upward; wherein the distribution plate is arranged horizontally;

[0041] More preferably, the distribution plate is in the form of a flat plate, preferably a disc, more preferably a circular disc; and / or

[0042] There are multiple downcomers, which are preferably evenly distributed on the distribution plate; and / or

[0043] There are multiple downholes, which are preferably evenly distributed on the distribution plate, and more preferably, the downholes are arranged between two adjacent downcomers.

[0044] In a preferred embodiment of the present invention,

[0045] The inner diameter of the downcomer is 15 to 50 mm, preferably 19 to 44 mm; and / or

[0046] The height of the downcomer is 10 to 50 cm, preferably 20 to 30 cm; and / or

[0047] The shape of the lower liquid hole is any one of circular, square, rhombus, pentagon and hexagon;

[0048] Preferably, the lower liquid hole is circular, and the inner diameter of the lower liquid hole is 1 to 6 mm, preferably 0.5 to 5 mm.

[0049] In a preferred embodiment of the present invention,

[0050] The ratio of the distance between the centers of two adjacent downcomers to the inner diameter of the downcomers is 1.2 to 1.5:1; and / or

[0051] The ratio of the hole center distance between two adjacent downhole holes to the inner diameter of the downcomer is 1.2-1.5:1; and / or

[0052] The distance between the distribution plate and the second tube plate is 5 to 150 mm, preferably 50 to 100 mm.

[0053] In a preferred embodiment of the present invention,

[0054] The heat exchange tube bundle comprises a plurality of vertically arranged heat exchange tubes, and the plurality of heat exchange tubes correspond vertically to the plurality of lower liquid holes one by one; and / or

[0055] In the horizontal direction, a feed baffle is vertically provided between the feed nozzle and the downcomer, the outer edge of the side of the feed baffle is fixed on the side wall of the reactor, and the lower edge thereof is higher than the distribution plate; the orthographic projection of the feed baffle on the side wall of the reactor covers the feed nozzle;

[0056] Preferably,

[0057] The vertical distance between the lower edge of the feed baffle and the distribution plate is 1 / 15 to 1 / 2 of the height of the downcomer; and / or

[0058] The horizontal distance between the middle of the feed baffle and the feed nozzle is 1 / 4 to 1 of the diameter of the feed nozzle.

[0059] The fifth object of the present invention is to provide a method for synthesizing MIBK, which is carried out using the system for synthesizing MIBK of the fourth object of the present invention.

[0060] In a preferred embodiment of the present invention, acetone enters the reactor from the feed nozzle, and hydrogen enters the reactor from the hydrogen feed pipe; acetone and hydrogen enter the heat exchange tube from the lower liquid hole and the downcomer respectively to react to obtain a crude MIBK product; the crude MIBK product sequentially enters the separator, the first distillation tower, the second distillation tower, the dehydration tower described in one of the purposes of the present invention, and the fourth distillation tower to obtain MIBK.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] The present invention can save the water phase pump and oil phase pump in the prior art by arranging a dehydration tower condenser at the top of the dehydration tower and arranging a liquid collecting tray in the upper part. The dehydration tower of the present invention organically combines multiple devices and merges functions, which saves land and investment and reduces energy consumption of the device on the one hand; on the other hand, it breaks through the limitations of the pump in the prior art, increases the flow rate, further enhances the chromatography effect, improves product quality and production efficiency, and makes the control more stable and more convenient to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 It is a dehydration tower of the prior art;

[0064] Figure 2 A dehydration tower which is one of the objects of the present invention;

[0065] Figure 3The MIBK distillation device for the third purpose of the present invention;

[0066] Figure 4 A system for synthesizing MIBK according to the fourth object of the present invention;

[0067] Figure 5 A schematic diagram of the main structure of the reactor in the system for synthesizing MIBK according to the fourth object of the present invention;

[0068] Figure 6 A schematic diagram of the main structure of the gas-liquid distributor, the left feed nozzle, the right feed nozzle, the hydrogen feed pipe, and the feed baffle in the system for synthesizing MIBK according to the fourth object of the present invention;

[0069] Figure 7 A schematic diagram of a top view of a distribution plate, a downcomer, a left feed nozzle, and a right feed nozzle in a system for synthesizing MIBK according to the fourth object of the present invention;

[0070] Figure 8 for Figure 6 A is a partial enlarged schematic diagram;

[0071] Fig. 9 A schematic diagram of a partial top view of the structure of the heat exchange tube, the tube bridge center and the second tube sheet in the system of synthesizing MIBK according to the fourth object of the present invention;

[0072] Fig.10 It is a schematic diagram of the main structure of a tubular fixed bed reactor in the prior art.

[0073] In the accompanying drawings,

[0074] 1-left feed nozzle; 2-right feed nozzle; 3-feed baffle; 4-downcomer; 5-distribution plate; 6-hydrogen feed pipe; 7-lower liquid hole; 8-heat exchange tube; 9-tube bridge center; 10-second tube sheet;

[0075] 11-dehydration tower condenser; 12-liquid collecting tray; 13-riser pipe; 14-baffle. DETAILED DESCRIPTION

[0076] The invention will be further described below in conjunction with the accompanying drawings.

[0077] The present invention relates to a dehydration tower, such as Figure 2As shown, the dehydration tower includes a dehydration tower body, a dehydration tower condenser 11 arranged at the top of the dehydration tower body, and a liquid collecting pan 12 arranged horizontally in the upper part of the dehydration tower body; an air riser 13 is arranged upward on the liquid collecting pan 12, and the air riser 13 is a through pipe that passes through from top to bottom, a baffle 14 is arranged on the top, and the bottom is connected to the liquid collecting pan 12. Specifically, the liquid collecting pan 12 is disc-shaped, and its outer edge is tightly and sealedly connected to the inner wall of the dehydration tower body. An air riser 13 extending upward is arranged at the center of the liquid collecting pan 12, which serves as a gas phase channel. A baffle 14 is connected to the top of the air riser 13 to prevent condensate from entering the air riser 13 and then dripping onto the filler of the lower section of the dehydration tower body.

[0078] The gas phase in the dehydration tower body moves from bottom to top through the riser 13. The gas phase flow rate in the riser 13 is determined by the ratio of the gas phase amount in the dehydration tower body to the cross-sectional area of ​​the dehydration tower body. The gas phase flow rate in the riser 13 cannot exceed 30m / s. Preferably, the flow rate of the gas phase is 5 to 15m / s. The inner diameter of the riser 13 is related to the gas phase flow rate. In a preferred embodiment of the present invention, the inner diameter of the riser 13 is 1 / 8 to 3 / 8 of the inner diameter of the dehydration tower body. Since the outer edge of the liquid collecting tray 12 is fixedly connected to the inner wall of the dehydration tower body, the inner diameter of the riser 13 is also 1 / 8 to 3 / 8 of the inner diameter of the liquid collecting tray 12.

[0079] The height of the riser 13 determines the height that the condensate level on the liquid collecting pan 12 can reach. Since the inner diameter of the dehydration tower body is fixed, the height of the condensate level on the liquid collecting pan 12 determines the volume of condensate that the liquid collecting pan 12 can accommodate. In a preferred embodiment of the present invention, the height of the riser 13 is 1 / 50 to 1 / 10 of the height of the dehydration tower body, preferably 1 / 25 to 2 / 25. It should be noted that the volume of the condensate here refers to the spatial volume within the dehydration tower body, from the liquid collecting pan 12 to the horizontal height of the upper edge of the riser 13, and the volume of the riser 13 portion needs to be removed.

[0080] In a preferred embodiment of the present invention, the distance between the top surface of the riser 13 and the dehydration tower condenser 11 is preferably 0.3 to 2 m, more preferably 0.4 to 1 m. It should be noted that the distance here is specifically the distance between the top surface of the riser 13 and the lower edge of the dehydration tower condenser 11. The pressure drop of the dehydration tower condenser 11 is not more than 20 kpa. After the gas phase mixture is condensed into a liquid phase by the dehydration tower condenser 11, it falls into the liquid collection tray 12 under the action of gravity, and is collected on the liquid collection tray 12 and chromatographed. Preferably, the condensation temperature of the dehydration tower condenser 11 is 40 to 82 ° C, more preferably 40 to 50 ° C. The lower the condensation temperature, the more conducive to the stratification of the two phases. The dehydration tower condenser 11 can adopt the top condenser commonly used in the prior art, preferably a spiral plate condenser, or an ordinary shell and tube heat exchanger, and can be liquid-sealed through the liquid phase return line to achieve supercondensation.

[0081] In a preferred embodiment of the present invention, the baffle 14 is connected to the riser 13 through at least two support members. At least two of the support members are preferably arranged at equal intervals. Specifically, the support member may be a support rod, the lower end of which is connected to the upper edge of the riser 13. The orthographic projection of the baffle 14 on the horizontal plane covers the orthographic projection of the riser 13 on the horizontal plane, that is, the position and cross-sectional area of ​​the baffle 14 can cover the top outlet of the riser 13. The baffle 14 can be set to an umbrella shape, a semicircle, a triangle, a square, etc., preferably an umbrella shape or a semicircle, which is convenient for processing and manufacturing on the one hand, and is conducive to the downward movement of the condensate on the other hand. After the gas phase encounters the baffle 14 during the upward movement, it cannot continue to move upward. Since only the support rod is connected between the baffle 14 and the riser 13, the gas phase will move along the lower surface of the baffle 14 toward the pipe wall until there is no baffle 14 above, and then continue to move upward, and finally rise to the dehydration tower condenser 11.

[0082] In a preferred embodiment of the present invention, a gas phase feed port is provided in the middle of the dehydration tower body and a tower kettle extraction is provided at the bottom. Specifically, the gas phase mixture after the reaction enters the dehydration tower body from the gas phase feed port. The gas phase mixture entering the dehydration tower body moves upward, passes through the gas riser 13 in the middle of the liquid collecting plate 12, and enters the dehydration tower condenser 11. After condensing into a liquid phase, it falls into the liquid collecting plate 12 under the action of gravity, and is collected on the liquid collecting plate 12 and chromatographed. The condensate of the gas phase mixture mainly includes about 15-40% water, 5-30% isopropanol, 30-60% MIBK and less than 2% acetone, and the percentages here refer to mass percentages. Among them, water and MIBK are completely insoluble, isopropanol is soluble in both water and MIBK, and acetone is also soluble in both water and oil phases. Therefore, the condensate on the liquid collecting tray 12 will form a water phase and an oil phase after standing, and isopropanol will be dissolved in both phases. The oil phase includes methyl isobutyl ketone, isopropanol and acetone. The density of water is greater than that of the oil phase, so the water phase is at the bottom and the oil phase is at the top. It should be noted that it is necessary to ensure that the condensate on the liquid collecting tray 12 has a certain standing time so that the liquid phase can be separated into layers. Preferably, the standing time of the condensate is 10 to 250 minutes, more preferably 30 to 180 minutes.

[0083] After standing, the extraction can be carried out. The two sides of the dehydration tower body are provided with oil phase extraction and water phase extraction, both of which are higher than the liquid collection tray 12. Except for water extracted through the water phase, the other three substances are extracted through the oil phase. Preferably, a water phase boundary level meter is provided on the water phase extraction pipeline; an oil phase boundary level meter is provided on the oil phase extraction pipeline. More preferably, the oil phase extraction pipeline is respectively connected to the oil phase separation tower and the light component storage tank, and is also connected to the reflux pipeline to reflux part of the extracted oil phase into the dehydration tower body, and the reflux pipeline inlet is arranged below the liquid collection tray at the position of the dehydration tower body. Specifically in this embodiment, the acetone tower is the oil phase separation tower.

[0084] In this embodiment, if Figure 2As shown, the water phase is discharged to the wastewater tower through the water phase level meter, and the extraction speed can be adjusted by adjusting the level meter. Similarly, the oil phase is extracted through the oil phase level meter. Unlike the water phase extraction, the oil phase extraction is divided into three routes: under the action of gravity, one route goes to the acetone tower (i.e., the oil phase separation tower) to separate acetone and isopropanol, another route goes to the light component storage tank, and the rest flows back to the dehydration tower body. It should be noted that the inlet of the reflux pipeline is located below the liquid collection tray 12 at the position of the dehydration tower body. Since the liquid collection tray 12 is located at a higher position, it can directly flow back to the dehydration tower body under the action of gravity, and does not need to be realized by a pump. Similarly, the water phase extraction, acetone tower extraction, and light component tank extraction also utilize gravity difference and do not need to be realized by a pump. After the remaining oil phase flows back to the dehydration tower body, it passes downward through the packing layer, is extracted from the dehydration tower kettle, and enters the subsequent fourth distillation tower E4. It should be noted that the dehydration tower kettle can be heated, liquid re-vaporized, condensed, chromatographic refluxed, etc., which is conducive to further improving the purity of the product. The dehydration tower of the present invention integrates the condenser, reflux tank, and two extraction pumps in the prior art, and only requires a dehydration tower body, a dehydration tower condenser 11 arranged on the upper part thereof, and a liquid collecting tray 12.

[0085] At present, the largest MIBK unit in China is only 15,000 tons. If the traditional dehydration process is adopted, the flow rate of the oil phase pump and the water phase pump at the top of the tower is less than 1m 3 / h, even if you buy the smallest oil phase pump and water phase pump, the flow rate is at least 3-5m 3 / h, so only the minimum reflux can be set to meet the normal operation of the pump. However, in the process of returning to the dehydration tower with the minimum reflux, the minimum reflux line of the pump will return to the chromatograph. This is because the chromatograph in the prior art is an external tank, and the pump has been running at a small flow rate for a long time. On the one hand, the efficiency is low, and on the other hand, the chromatography effect is not good, and the quality of the final product will also be affected. The dehydration tower of the present invention breaks through the limitations of the pump in the prior art, uses gravity for flow control, and solves the problem of using pumps to control flow in the prior art. On the one hand, it saves space and investment and reduces energy consumption of the device; on the other hand, it breaks through the limitations of the pump in the prior art, so that the chromatography effect is further enhanced, the control is more stable, and it is more convenient to operate.

[0086] The present invention also relates to a dehydration method of the aforementioned dehydration tower, comprising the following steps: the reaction gas phase mixture enters the dehydration tower through the gas phase feed port of the dehydration tower, the gas phase mixture moves upward, passes through the riser 13 in the middle of the liquid collecting tray 12, enters the dehydration tower condenser 11, and is condensed into a liquid phase, and then falls into the liquid collecting tray 12 under the action of gravity, and is collected on the liquid collecting tray 12 and chromatographed. Preferably, the condensation temperature of the dehydration tower condenser 11 is 40 to 82°C, more preferably 40 to 50°C; and / or the pressure drop of the dehydration tower condenser 11 is not greater than 20kpa.

[0087] The condensate liquid phase collected on the liquid collection tray 12 forms an oil phase at the top and a water phase at the bottom after standing. Preferably, the water phase is produced by the water phase boundary level meter to control the extraction; the oil phase is produced by the oil phase boundary level meter to control the extraction and is divided into three routes: one route to oil phase separation, another route to the light component storage tank, and the rest is refluxed into the dehydration tower body. More preferably, the standing time of the condensate collected on the liquid collection tray 12 is 10 to 250 minutes, preferably 30 to 180 minutes; and / or 10 to 20% of the oil phase is discharged to the oil phase separation tower, 5 to 20% is discharged to the light component storage tank, and the remaining oil phase is refluxed through the reflux pipeline. It should be noted that the percentages here are volume percentages, because the extraction is controlled by the boundary level meter. Specifically, Figure 2 In the process, 10-20% of the oil phase is discharged to the acetone tower for extraction, and the organic isopropanol in the oil phase is recovered in the acetone tower, and the isopropanol is returned to the upstream, so that the isopropanol is enriched in the whole system; 5-20% of the oil phase is discharged to the light component tank for extraction, and the remaining oil phase is completely refluxed to the dehydration tower body through the reflux pipeline. It should be noted that the percentages here are also volume percentages.

[0088] The present invention also relates to a MIBK distillation device, such as Figure 3 As shown, it includes, from left to right, a first distillation tower E1, a second distillation tower E2, a third distillation tower and a fourth distillation tower E4. It should be noted that the third distillation tower is a dehydration tower, which is one of the purposes of the present invention. The crude MIBK product and the circulating gas after the reaction are condensed, separated at low temperature and enter the first distillation tower E1, the unreacted acetone is separated in the second distillation tower E2, the light components of isopropanol and water are separated in the third distillation tower (i.e., the aforementioned dehydration tower), and the pure MIBK product is obtained at the top of the fourth distillation tower E4. The first distillation tower E1, the second distillation tower E2 and the fourth distillation tower E4 of the present invention can adopt the conventional design of the synthetic MIBK distillation device in the prior art.

[0089] The present invention also relates to a system for synthesizing MIBK, such as Figure 4 As shown, the system comprises a reactor, a separator and the aforementioned distillation device in sequence. In one preferred embodiment of the present invention, as Figure 5 As shown, the reactor includes, from bottom to top, a first tube sheet, a heat exchange tube bundle, a second tube sheet 10, a gas-liquid distributor, a feed nozzle disposed on the side wall of the reactor, and a hydrogen feed pipe 6. Figure 5It can be seen that the hydrogen feed pipe 6 is arranged at the top of the reactor, and the gas phase enters the reactor through the hydrogen feed pipe 6. The feed nozzles include a left feed nozzle 1 and a right feed nozzle 2, both of which are arranged at the same height on the side of the reactor and are arranged opposite to each other. The liquid phase enters the reactor through the left feed nozzle 1 and the right feed nozzle 2. In the vertical direction, the height of the lower edge of the left feed nozzle 1 and the right feed nozzle 2 is not lower than the height of the distribution plate 5. The gas-liquid distributor is horizontally arranged in the reactor and is located at the upper part of the reactor. Specifically, the outer edge of the distribution plate 5 is connected to the inner wall of the reactor, and its outer edge is tightly fitted to the inner wall of the reactor.

[0090] The gas-liquid distributor comprises a distribution plate 5, a lower liquid hole 7 provided on the distribution plate 5, and a downcomer 4 provided on the distribution plate 5 and extending upward. The downcomer 4 is vertically provided on the upper surface of the distribution plate 5. The downcomer 4 is connected vertically (i.e., the lower port of the downcomer 4 is located on the distribution plate 5 and is a through hole, and the upper port and the lower port of the downcomer 4 are unobstructed to form a through pipe) as a gas phase channel. The lower liquid hole 7 is connected vertically as a liquid phase channel.

[0091] In a preferred embodiment of the present invention, Figure 6 to Figure 8 As shown, the distribution plate 5 is in the shape of a flat plate, preferably a disc, and more preferably a circular disc. On the upper surface of the distribution plate 5, a plurality of downcomers 4 extending upward are vertically arranged. The downcomers 4 are multiple, preferably evenly distributed on the distribution plate 5. A lower liquid hole 7 is opened on the distribution plate 5 and between the downcomers 4. The lower liquid holes 7 are multiple, preferably evenly distributed on the distribution plate 5, and more preferably the lower liquid hole 7 is arranged between two adjacent downcomers 4.

[0092] In order to better achieve uniform entry of the gas-liquid two-phase into the pipe process, in one of the preferred embodiments of the present invention, the flow rate of the gas phase through the downcomer 4 is not more than 10m / s, or the pressure drop when passing through the downcomer 4 does not exceed 0.1kpa. Preferably, the flow rate of the gas phase through the downcomer 4 is 0.001-10m / s, more preferably, 0.01-5m / s; or, the pressure drop when the gas passes through the downcomer 4 is preferably 0.01-0.08kpa. More preferably, the inner diameter of the downcomer 4 is preferably 15-50mm, more preferably 19-44mm. Furthermore, the height of the downcomer 4 is 10-50cm, preferably 20-30cm. The ratio of the tube center distance between two adjacent downcomers 4 to the inner diameter of the downcomer 4 is 1.2-1.5:1.

[0093] In order to better achieve uniform entry of gas and liquid into the pipe side, in one preferred embodiment of the present invention, the shape of the lower liquid hole 7 can be any one of circular, square, diamond, pentagonal, and hexagonal. Furthermore, the preferred shape of the lower liquid hole 7 is circular, and the preferred inner diameter of the lower liquid hole 7 is 1 to 6 mm, preferably 0.5 to 5 mm. The area of ​​the lower liquid hole 7 is related to the height of the downcomer 4 to ensure uniform entry of gas and liquid into the pipe side. It should be noted that Figure 3 The circular lower liquid hole 7 does not constitute a limitation to the present invention, as long as the area of ​​the lower liquid hole 7 can make the flow rate of the liquid phase meet the preset requirements. The flow rate of the liquid phase through the lower liquid hole 7 is 0.1 to 3 m / s, preferably 0.2 to 0.6 m / s. Furthermore, the ratio of the hole center distance between two adjacent lower liquid holes 7 to the inner diameter of the downcomer 4 is 1.2 to 1.5:1.

[0094] In the horizontal direction, a feed baffle 3 is vertically arranged between the feed nozzle and the downcomer 4, and the outer edge of the side of the feed baffle 3 is fixed on the side wall of the reactor, and its lower edge is higher than the distribution plate 5; the orthographic projection of the feed baffle 3 on the side wall of the reactor covers the feed nozzle. Taking the left side as an example, in the horizontal direction, a feed baffle 3 is vertically arranged between the left feed nozzle 1 and the downcomer 4 to prevent the liquid phase from entering the gas phase channel from the top surface of the downcomer 4 when entering the reactor from the left feed nozzle 1. The orthographic projection of the feed baffle 3 on the side wall of the reactor is sufficient to cover the orthographic projection of the left feed nozzle 1 on the side wall of the reactor. Preferably, the feed baffle 3 is arc-shaped, and the position and area of ​​the feed baffle 3 are sufficient to cover the nozzle opening of the left feed nozzle 1. In the horizontal direction, the left and right outer edges of the feed baffle 3 are connected to the inner wall of the reactor on the left and right sides of the left feed nozzle 1. In the vertical direction, the height of the upper edge of the feed baffle 3 is higher than the upper edge of the left feed nozzle 1 and higher than the upper edge of the downcomer 4; the height of the lower edge of the feed baffle 3 is lower than the lower edge of the left feed nozzle 1 and lower than the upper edge of the upcomer 4; the height of the lower edge of the feed baffle 3 is higher than the height of the distribution plate 5, so that the liquid phase entering from the left feed nozzle 1 falls on the distribution plate 5 and forms a liquid level of a certain height. More preferably, the vertical distance between the lower edge of the feed baffle 3 and the distribution plate 5 is 1 / 15 to 1 / 2 of the height of the downcomer 4, and the horizontal distance between the middle of the feed baffle 3 and the middle of the left feed nozzle 1 is 1 / 4 to 1 of the diameter of the left feed nozzle 1. It should be noted that the downcomer 4 here is the downcomer 4 closest to the left feed nozzle 1. Similarly, a similar feed baffle 3 is provided between the right feed nozzle 2 and the downcomer 4 closest thereto, and the specific descriptions are the same as those on the left side above.

[0095] In the actual MIBK production process, hydrogen enters the reactor through the hydrogen feed pipe 6. Acetone enters the reactor through the left feed nozzle 1 and the right feed nozzle 2. After acetone enters the reactor, it is deflected by the feed baffle 3, and the liquid phase falls on the distribution plate 5 to form a certain liquid level and a certain static pressure head. It should be noted that the liquid level formed by the liquid phase is located in the middle of the downcomer 4, and its liquid level is automatically controlled by a flow meter. Liquid phase acetone moves downward from the lower liquid hole 7. By reasonably setting the inner diameter of the downcomer 4, the flow rate of hydrogen moving downward can be controlled. Similarly, the flow rate of acetone moving downward can be controlled by setting the area of ​​the lower liquid hole 7, so that it matches the flow rate of the gas phase moving downward. Since the height of the downcomer 4 determines the maximum height of the acetone liquid layer on the distribution plate 5 and the static pressure head formed by the acetone liquid layer, the area of ​​the lower liquid hole 7 can be determined, so that the acetone flows downward evenly and matches the flow rate of the gas phase moving downward.

[0096] A disc-shaped tube sheet is provided under the distributor, preferably a disc-shaped tube sheet; its outer edge is connected to the inner wall of the reactor and is arranged horizontally, and the outer edge of the tube sheet and the inner wall of the reactor are closely fitted. Figure 4 As shown, the tube sheet includes a second tube sheet 10 adjacent to the lower edge of the gas-liquid distributor and a first tube sheet adjacent to the bottom of the reactor. The first tube sheet and the second tube sheet 10 are evenly provided with a plurality of through holes that can accommodate heat exchange tube bundles. The heat exchange tube bundles are composed of a plurality of vertically arranged heat exchange tubes 8. The arrangement of the through holes is the same as that of the heat exchange tubes 8, so as to allow a plurality of the heat exchange tubes 8 to pass through respectively. The distance between the distribution plate 5 and the second tube sheet 10 is 5 to 150 mm, preferably 50 to 100 mm. The inner diameter of the heat exchange tube 8 is 15 to 50 mm, preferably 19 to 44 mm. The ratio of the tube center distance between two adjacent heat exchange tubes 8 to the inner diameter of the heat exchange tube 8 is 1.2 to 1.5:1.

[0097] The plurality of heat exchange tubes 8 correspond vertically to the plurality of lower liquid holes 7, respectively, and the number of the heat exchange tubes 8 is the same as the number of the lower liquid holes 7. Preferably, the lower liquid holes 7 are coaxially arranged with the heat exchange tubes 8, the inner diameter of the lower liquid holes 7 is smaller than the inner diameter of the corresponding heat exchange tubes 8, and the center of the orthographic projection of the lower liquid holes 7 on the horizontal plane coincides with the center of the orthographic projection of the heat exchange tubes 8 on the horizontal plane. The liquid phase moving downward through the lower liquid holes 7 drips at a uniform speed into the heat exchange tubes 8 located below them.

[0098] The portion of the tube sheet connecting the adjacent heat exchange tubes 8 is the tube bridge. Fig. 9As shown, the heat exchange tubes 8 are arranged in an angular equilateral triangle. Taking three adjacent heat exchange tubes 8 as an example, the centers of the three heat exchange tubes 8 are connected together to form a triangular area, and the center of the triangular area is the tube bridge center 9. Preferably, the downcomer 4 and the tube bridge center 9 may correspond vertically; more preferably, each tube bridge center 9 corresponds to a downcomer 4. That is, the center of the orthographic projection of the downcomer 4 on the horizontal plane coincides with the tube bridge center 9. It should be noted that since it is easier for the gas phase to change direction, the number of the downcomers 4 does not necessarily have to be the same as the number of the heat exchange tubes 8, and the center of the orthographic projection of the downcomer 4 on the horizontal plane does not necessarily coincide with the tube bridge center 9. The fact that the center of the orthographic projection of the downcomer 4 on the horizontal plane coincides with the tube bridge center 9 is merely an exemplary description and does not constitute a new limitation on the present invention. Similarly, Figure 5 The arrangement of the plurality of heat exchange tubes 8 on the tube sheet is also only an exemplary description, which does not limit the arrangement of the heat exchange tubes 8, and other polygonal arrangements are also possible.

[0099] Hydrogen and acetone flow downward uniformly from the downcomer 4 and the lower liquid hole 7, respectively. Acetone enters the heat exchange tube 8, and hydrogen also enters the heat exchange tube 8. This is because although the center of the orthographic projection of the downcomer 4 on the horizontal plane coincides with the center of the pipe bridge 9, due to the obstruction of the pipe bridge, part of the hydrogen located above the pipe bridge cannot continue to move downward along the pipe bridge, so part of the hydrogen located above the pipe bridge also changes direction and enters the heat exchange tube 8 near the center of the pipe bridge 9 and continues to move downward. The hydrogen moves uniformly downward into the heat exchange tube 8 through the downcomer 4, and the acetone on the distribution plate 5 moves uniformly downward into the heat exchange tube 8 through the lower liquid hole 7, so as to ensure that the gas-liquid two-phases evenly enter each heat exchange tube 8. The gas-liquid two-phases react under the catalytic action of the catalyst in the heat exchange tube 8 to obtain MIBK.

[0100] The other parts of the reactor for synthesizing MIBK of the present invention can adopt the conventional design of the reactor for synthesizing MIBK in the prior art.

[0101] The present invention also relates to a method for synthesizing MIBK, which is carried out using the above-mentioned system for synthesizing MIBK. In one specific embodiment of the present invention, acetone enters the reactor from the feed nozzle, and hydrogen enters the reactor from the hydrogen feed pipe; acetone and hydrogen enter the heat exchange tube bundle from the lower liquid hole and the downcomer respectively to react to obtain a crude MIBK product; the crude MIBK product enters the separator, the first distillation tower E1, the second distillation tower E2, the dehydration tower, and the fourth distillation tower E4 in sequence to obtain MIBK.

[0102] Example 1

[0103] In a preferred embodiment of the present invention, the Figures 2 to 9The structure shown is provided with the system of the reactor, the separator, the first distillation tower E1, the second distillation tower E2, the dehydration tower, and the fourth distillation tower E4 to carry out the MIBK synthesis reaction. The dehydration tower has a diameter of 1500 mm and a height of 38000 mm. The distance between the liquid collecting tray 12 and the lower edge of the dehydration tower condenser 11 is 3000 mm. The middle part of the liquid collecting tray 12 is provided with an upwardly extending riser 13, and the diameter of the riser 13 is 250 mm and the height is 2500 mm. The dehydration process is as follows: after the reaction gas phase mixture is vaporized (flow rate is about 1000 kg / h), it moves upward along the riser 13 to the dehydration tower condenser 11, and the pressure drop of the dehydration tower condenser 11 is 3.5 kpa. The condensation temperature of the dehydration tower condenser 11 is 40°C. After the gas phase mixture is condensed, a condensate is obtained, and the condensate falls to the liquid collecting tray 12 under the action of gravity. The residence time of the condensate in the liquid collecting tray 12 is 2.79h. Except for water produced through the water phase (69kg / h), the other three substances are produced through the oil phase (931kg / h), of which 15% of the oil phase is discharged to the acetone separation tower, 15% is discharged to the light component storage tank, and the remaining oil phase is refluxed to the dehydration tower. It should be noted that the percentages here are volume percentages.

[0104] The reactor has a diameter of 1900 mm, wherein the heat exchange tube bundle is provided with 1216 heat exchange tubes 8; the outer diameter of the heat exchange tube 8 is 38 mm, the inner diameter is 32 mm, and the height is 9 m; the tube center distance between two adjacent heat exchange tubes 8 is 47.5 mm. The lower end of the heat exchange tube is arranged in the first tube sheet, and the upper end is arranged in the second tube sheet 10. The distribution plate 5 of the gas-liquid distributor of the present invention is arranged 100 mm above the second tube sheet 10, and the distribution plate 5 is provided with 1216 downwardly extending gas downpipes 4, the outer diameter of the gas downpipe 4 is 38 mm, the inner diameter is 32 mm, and the height is 30 cm, and the tube center distance between two adjacent gas downpipes 4 is 47.5 mm. The multiple gas downpipes 4 correspond vertically to the multiple tube bridge centers 9 one by one. The distribution plate 5 is provided with 1216 lower liquid holes 7, the inner diameter of the lower liquid hole 7 is 3 mm, and the hole center distance between two adjacent lower liquid holes is 47.5 mm. The plurality of heat exchange tubes 8 correspond to the plurality of lower liquid holes 7 vertically and are coaxially arranged one by one. The flow rate of hydrogen in the downcomer 4 is 0.015 m / s, and the flow rate of acetone in the lower liquid hole 7 is 9 m / s. The feed nozzle is arranged higher than the distribution plate 5, and includes a left feed nozzle 1 and a right feed nozzle 2, which are arranged at the same height on the side of the reactor and are arranged opposite to each other. The diameter of the feed nozzle is 80 mm. The feed baffle 3 consists of two pieces, which are respectively arranged between the feed nozzle and the downcomer closest to the inner wall of the reactor; the distance between the middle of the feed baffle 3 and the feed nozzle is 80 mm. The height of the feed baffle 3 is 30 cm, and the distance between the lower edge of the feed baffle 3 and the distribution plate is 54 mm.

[0105] Comparative Example 1

[0106] like Figure 1 The dehydration tower (tower diameter 1.5m, tower height 36m) of the prior art shown in the figure removes water and isopropanol from the top of the tower. The conventional process is as follows: after the top material of the dehydration tower enters the dehydration tower condenser, it is condensed into a liquid phase and enters the dehydration tower reflux tank. The reflux tank (diameter 1500mm, length 3m) is used as a reflux buffer while also performing chromatography of the oil phase (931kg / h) and the water phase (69kg / h). The water phase is pumped to the wastewater tower, and the oil phase is pressurized by a pump and then divided into three streams, one of which is returned to the tower for reflux, one is sent to the acetone tower, and one is sent to the light component tower.

[0107] like Fig.10 The prior art tubular fixed bed reactor shown in the figure has a liquid distributor, structured filler and honeycomb arranged in sequence at the top of the reactor; a wedge-shaped support plate is arranged at the bottom of the reactor, and catalyst is loaded in the tube and on the support plate, and the distributor of the reactor is complex in design.

[0108] Compared with the prior art of comparative example 1, the dehydration tower of Example 1 of the present invention can save the water phase pump and oil phase pump in the prior art, saving 36m2 of floor space. 2 , reducing the energy consumption of the device and saving 1-2kW of electricity per hour. At the same time, it breaks through the limitations of the pump in the existing technology, increases the flow rate, further enhances the chromatography effect, improves product quality and production efficiency, and makes the control more stable and more convenient to operate.

[0109] Furthermore, the gas-liquid distributor of Example 1 of the present invention can make the gas-liquid two-phase enter the heat exchange tube more evenly. This is because the prior art distributor is provided with random packing and honeycomb packing below, and the packing will inevitably have wall effect and channel flow, and the smaller the packing height, the more obvious the wall effect. The gas-liquid distributor of Example 1 of the present invention ensures that the flow rate of the liquid phase dripping from each lower liquid hole 7 is consistent through the uniform liquid level and static pressure head distribution on the distribution plate 5, that is, the liquid phase flow rate entering each heat exchange tube 8 is ensured to be consistent. At the same time, a downcomer 4 is provided to ensure that the gas phase can pass through the distribution plate 5 evenly and enter each heat exchange tube 8 evenly. In Comparative Example 1, the selectivity of the MIBK synthesis reaction is 94%, and the life of the catalyst is 7200h. In Example 1, since the gas-liquid two-phase enters the heat exchange tube 8 evenly, on the one hand, the selectivity of the reaction will be improved to 94.2%; on the other hand, the hot spot temperature is easier to control, and the reactor is not prone to temperature runaway. In addition, the uniform entry of the gas-liquid two-phase into the heat exchange tube 8 will also extend the life of the catalyst. In this embodiment, the life of the catalyst can reach 8000 hours.

Claims

1. A dehydration tower, characterized in that: The dehydration tower includes a dehydration tower body, a dehydration tower condenser arranged on the top of the dehydration tower body, and a liquid collecting pan horizontally arranged in the upper part of the dehydration tower body; an air riser is arranged upward on the liquid collecting pan, and the air riser is a through pipe with a baffle on the top and connected to the liquid collecting pan at the bottom.

2. The dehydration tower according to claim 1, characterized in that: The inner diameter of the riser is 1 / 8 to 3 / 8 of the inner diameter of the dehydration tower body; and / or The height of the riser is 1 / 50 to 1 / 10 of the height of the dehydration tower body, preferably 1 / 25 to 2 / 25.

3. The dehydration tower according to claim 1, characterized in that: The distance between the top surface of the riser and the dehydration tower condenser is 0.3 to 2 m, preferably 0.4 to 1 m; and / or The condensation temperature of the dehydration tower condenser is 40-82°C, preferably 40-50°C.

4. The dehydration tower according to claim 1, characterized in that: The edge of the liquid collecting tray is fixedly connected to the inner wall of the dehydration tower body; and / or A baffle is connected above the riser, and the baffle is connected to the liquid collecting tray through at least two supporting members; the orthographic projection of the baffle on the horizontal plane covers the orthographic projection of the riser on the horizontal plane; Preferably, the baffle is any one of an umbrella shape, a semicircular shape, a triangle shape, and a square shape; More preferably, the baffle is umbrella-shaped or semicircular.

5. The dehydration tower according to claim 1, characterized in that: The dehydration tower body is provided with a gas phase feed inlet in the middle and a tower bottom outlet at the bottom; and / or The oil phase extraction and water phase extraction are arranged on both sides of the dehydration tower body, both of which are higher than the liquid collecting tray, and the oil phase extraction position is higher than the water phase extraction position.

6. The dehydration tower according to claim 5, characterized in that: A water level meter is arranged on the pipeline for producing the water phase; and / or An oil phase level meter is arranged on the oil phase production pipeline; and / or The oil phase production pipeline is connected to the oil phase separation tower and the light component storage tank respectively, and is also connected to the reflux pipeline to reflux part of the produced oil phase into the dehydration tower body. The reflux pipeline inlet is arranged below the liquid collection tray at the position of the dehydration tower body.

7. The dehydration method of a dehydration tower according to any one of claims 1 to 6, characterized in that The following steps are involved: The reaction gas phase mixture enters the dehydration tower body through the gas phase feed port of the dehydration tower, and the gas phase mixture moves upward, passes through the gas riser in the middle of the liquid collecting plate, enters the dehydration tower condenser, and is condensed into a liquid phase, and then falls into the liquid collecting plate under the action of gravity, and is collected on the liquid collecting plate and chromatographed; Preferably, the condensation temperature of the dehydration tower condenser is 40-82° C., more preferably 40-50° C.; and / or the pressure drop of the dehydration tower condenser is not greater than 20 kPa.

8. The dehydration method according to claim 7, characterized in that: The condensate liquid phase collected on the liquid collection tray forms an oil phase at the top and a water phase at the bottom after standing; preferably, The water phase is produced by controlling the water phase boundary level meter; and / or The oil phase is produced by the oil phase level meter and is divided into three routes: one route is for oil phase separation, another route is for light component storage tank, and the rest is returned to the dehydration tower body.

9. The dehydration method according to claim 8, characterized in that: The condensate collected on the liquid collection tray is allowed to stand for 10 to 250 minutes, preferably 30 to 180 minutes; and / or 10-20% of the oil phase produced is discharged to the oil phase separation tower, 5-20% is discharged to the light component storage tank, and the remaining oil phase is refluxed through the reflux pipeline.

10. A distillation device, characterized in that: It comprises a dehydration tower according to any one of claims 1 to 6; preferably, the distillation device comprises a first distillation tower, a second distillation tower, the dehydration tower and a fourth distillation tower connected in sequence.

11. A system for synthesizing MIBK, characterized in that: The system comprises a reactor, a separator and the distillation device according to claim 10 which are connected in sequence.

12. The system according to claim 11, characterized in that: The reactor includes, from bottom to top, a first tube sheet, a heat exchange tube bundle, a second tube sheet, a gas-liquid distributor, a feed nozzle disposed on the side wall of the reactor, and a hydrogen feed pipe disposed on the top of the reactor; Preferably, the gas-liquid distributor comprises a distribution plate, a lower liquid hole opened on the distribution plate, and a downcomer provided on the distribution plate and extending upward; wherein the distribution plate is arranged horizontally; More preferably, the distribution plate is in the form of a flat plate, preferably a disc, more preferably a circular disc; and / or There are multiple downcomers, which are preferably evenly distributed on the distribution plate; and / or There are multiple downholes, which are preferably evenly distributed on the distribution plate, and more preferably, the downholes are arranged between two adjacent downcomers.

13. The system according to claim 12, characterized in that: The inner diameter of the downcomer is 15 to 50 mm, preferably 19 to 44 mm; and / or The height of the downcomer is 10 to 50 cm, preferably 20 to 30 cm; and / or The shape of the lower liquid hole is any one of circular, square, rhombus, pentagon and hexagon; Preferably, the lower liquid hole is circular, and the inner diameter of the lower liquid hole is 1 to 6 mm, preferably 0.5 to 5 mm.

14. The system according to any one of claims 12 to 13, characterized in that: The ratio of the distance between the centers of two adjacent downcomers to the inner diameter of the downcomers is 1.2 to 1.5:1; and / or The ratio of the hole center distance between two adjacent downhole holes to the inner diameter of the downcomer is 1.2-1.5:1; and / or The distance between the distribution plate and the second tube plate is 5 to 150 mm, preferably 50 to 100 mm.

15. The system according to claim 12, characterized in that: The heat exchange tube bundle comprises a plurality of vertically arranged heat exchange tubes, and the plurality of heat exchange tubes correspond vertically to the plurality of lower liquid holes one by one; and / or In the horizontal direction, a feed baffle is vertically provided between the feed nozzle and the downcomer, the outer edge of the side of the feed baffle is fixed on the side wall of the reactor, and the lower edge thereof is higher than the distribution plate; the orthographic projection of the feed baffle on the side wall of the reactor covers the feed nozzle; Preferably, The vertical distance between the lower edge of the feed baffle and the distribution plate is 1 / 15 to 1 / 2 of the height of the downcomer; and / or The horizontal distance between the middle of the feed baffle and the feed nozzle is 1 / 4 to 1 of the diameter of the feed nozzle.

16. A method for synthesizing MIBK, characterized in that: The method is carried out by using the system according to any one of claims 12 to 15; Preferably, acetone enters the reactor from the feed nozzle, and hydrogen enters the reactor from the hydrogen feed pipe; acetone and hydrogen enter the heat exchange tube bundle from the lower liquid hole and the downcomer respectively to react to obtain a crude MIBK product; the crude MIBK product sequentially enters the separator, the first distillation tower, the second distillation tower, the dehydration tower according to any one of claims 1 to 6, and the fourth distillation tower to obtain MIBK.

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