A dehydration tower, rectification device and system for synthesizing MIBK

Abstract

The present application relates to a kind of dehydration tower, it includes dehydration tower body, dehydration tower condenser is arranged in the top of the dehydration tower body, liquid collecting tray is horizontally arranged in the upper portion of the dehydration tower body;The gas-lift pipe is arranged upwards on the liquid collecting tray, gas-lift pipe is through pipe, its top is provided with baffle, bottom is communicated with the liquid collecting tray.By dehydration tower top setting dehydration tower condenser, upper portion setting liquid collecting tray, can save the water phase pump and oil phase pump in the prior art.The dehydration tower of the present application, a plurality of equipment are organically combined and function is merged, on the one hand, land occupation and investment are saved, device energy consumption is reduced;On the other hand, break the limitation of pump in the prior art, increase flow, make the chromatography effect further enhance, product quality and production efficiency are improved, and control is more stable, more convenient operation.In addition, the present application also provides the dehydration method of dehydration tower, the rectifying device comprising the aforementioned dehydration tower, the system for synthesizing MIBK and the method thereof.

Description

[0001] The field of the application

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

[0003] MIBK becomes a main auxiliary solvent for high-grade paint due to its good solubility and excellent mutual solubility with other solvents and suitable boiling point, and can meet the special requirements of high-grade paint on solid components, volatilization speed, leveling property, paint strength, appearance and the like.

[0004] In the prior art, MIBK is generated by one-step method through reaction of acetone and hydrogen under the action of a catalyst in a fixed bed reactor. The raw materials hydrogen and acetone are preheated, and then the reaction is carried out in the fixed bed reactor. The product after reaction and circulating gas are condensed, separated at low temperature and introduced into a first rectification tower. Unreacted acetone is separated in a second rectification tower, and light components water are separated in a third rectification tower. Pure MIBK product is obtained at the top of a fourth rectification tower, and the dehydration tower kettle contains a high amount of condensate. The production process has the advantages of short process, low investment, high acetone conversion rate, high MIBK selectivity, low raw material consumption and low energy consumption.

[0005] The third rectification tower is a dehydration tower (as shown in FIG. 1), water and isopropyl alcohol are removed at the top of the dehydration tower, and the conventional process is as follows. The material at the top of the dehydration tower is condensed into liquid phase and introduced into a reflux tank of the dehydration tower after entering a dehydration tower condenser. The reflux tank serves as a reflux buffer and also performs chromatography of oil phase and water phase. The water phase is pumped to a waste water tower, and the oil phase is pressurized by a pump and then divided into three streams. One stream is returned to the tower for reflux, one stream is sent to an acetone tower, and one stream is sent to a light component tower. Figure 1 The one-step synthesis process of MIBK requires a 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 1 m 3 / h. In the case of small flow rate, on the one hand, the pump efficiency is low, resulting in low production efficiency; on the other hand, the chromatography effect is affected. SUMMARY

[0006] In order to solve the problems in the prior art, the present application provides a dehydration tower, which organically combines and functionally integrates multiple devices. On the one hand, the dehydration tower saves land occupation and investment and reduces device energy consumption. On the other hand, the dehydration tower breaks through the limitation of the pump in the prior art, increases the flow rate, further enhances the chromatography effect, improves the product quality and production efficiency, and is more stable, convenient and easy to control.

[0007] One of the purposes of the present application is to provide a dehydration tower, which comprises a dehydration tower body, a dehydration tower condenser arranged at the top of the dehydration tower body, and a collecting tray horizontally arranged in the upper part of the dehydration tower body; an air lift pipe is arranged upwardly on the collecting tray, the air lift pipe is a through pipe, a baffle is arranged at the top of the air lift pipe, and the bottom of the air lift pipe is communicated with the collecting tray.

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

[0009] The inner diameter of the air lift pipe is 1 / 8-3 / 8 of the inner diameter of the dehydration tower body; and / or

[0010] The height of the air lift pipe is 1 / 50-1 / 10, preferably 1 / 25-2 / 25, of the height of the dehydration tower body.

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

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

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

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

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

[0016] A baffle is connected above the air lift pipe, the baffle is connected to the collecting tray through at least two supporting members, and the baffle covers the projection of the air lift pipe on a horizontal plane.

[0017] Preferably, the baffle is in any one of an umbrella shape, a semicircular shape, a triangular shape and a square shape.

[0018] More preferably, the baffle is in an umbrella shape or a semicircular shape.

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

[0020] A gas phase feeding port is arranged in the middle of the dehydration tower body, and a tower kettle outlet is arranged at the bottom of the dehydration tower body; and / or

[0021] Oil phase outlets and water phase outlets are arranged on both sides of the dehydration tower body, and the oil phase outlets and the water phase outlets are higher than the position of the collecting tray, and the position of the oil phase outlets is higher than that of the water phase outlets.

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

[0023] A water phase level gauge is arranged on the pipeline of the water phase outlet; and / or

[0024] The oil phase extraction pipeline is provided with an oil phase boundary level gauge; and / or

[0025] The oil phase extraction pipeline is connected with an oil phase separation tower and a light component storage tank respectively, and is connected with a reflux pipeline at the same time, and part of the extracted oil phase is refluxed into the dehydration tower body, and the inlet of the reflux pipeline is arranged below the liquid collecting tray.

[0026] The second purpose of the present application is to provide a dehydration method of the dehydration tower, and the dehydration method comprises the following steps.

[0027] The reaction gas phase mixture enters the dehydration tower body through the gas phase feeding port of the dehydration tower, and the gas phase mixture moves upwards, enters the dehydration tower condenser to be condensed into a liquid phase after the gas phase mixture passes through the riser in the middle of the liquid collecting tray, and then falls into the liquid collecting tray under the action of gravity, and the condensed liquid is collected on the liquid collecting tray and is subjected to chromatography;

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

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

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

[0031] The water phase is extracted through the water phase boundary level gauge; and / or

[0032] The oil phase is extracted through the oil phase boundary level gauge, and is divided into three paths: one path goes to the oil phase separation, another path goes to the light component storage tank, and the remaining oil phase is refluxed into the dehydration tower body.

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

[0034] The standing time of the condensed liquid collected on the liquid collecting tray is 10-250 min, and preferably 30-180 min; and / or

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

[0036] The third purpose of the present application is to provide a rectifying device comprising the dehydration tower, and preferably, the rectifying device comprises a first rectifying tower, a second rectifying tower, the dehydration tower and a fourth rectifying tower connected in sequence.

[0037] The fourth object of the present application is to provide a system for synthesizing MIBK comprising the rectification device of the third object of the present application.

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

[0039] The reactor comprises, from bottom to top, a first tube plate, a heat exchange tube bundle, a second tube plate, a gas-liquid distributor, a feed pipe nozzle arranged on the side wall of the reactor, and a hydrogen feed pipe arranged on the top of the reactor.

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

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

[0042] The gas downcomer is preferably uniformly distributed on the distribution plate; and / or

[0043] The lower liquid hole is preferably uniformly distributed on the distribution plate, and more preferably, the lower liquid hole is arranged between two adjacent gas downcomers.

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

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

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

[0047] The shape of the lower liquid hole is any one of a circle, a square, a rhombus, a pentagon, and a hexagon.

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

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

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

[0051] The ratio of the distance between the centers of two adjacent lower liquid holes to the inner diameter of the gas downcomer is 1.2-1.5:1; and / or

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

[0053] In one preferred embodiment of the present application,

[0054] The heat exchange tube bundle comprises a plurality of vertically arranged heat exchange tubes, and the plurality of heat exchange tubes are vertically corresponding to the plurality of liquid outlet holes respectively; and / or

[0055] In the horizontal direction, a feed baffle is vertically arranged between the feed nozzle and the downcomer, the side edge of the feed baffle is fixed to the side wall of the reactor, and the lower edge of the feed baffle 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 application is to provide a method for synthesizing MIBK, which is carried out by using the system for synthesizing MIBK according to the fourth object of the present application.

[0060] In one preferred embodiment of the present application, acetone enters the reactor from the feed nozzle, and hydrogen enters the reactor from the hydrogen feed pipe; the acetone and hydrogen enter the heat exchange tubes from the liquid outlet holes and the downcomer respectively to react to obtain a crude MIBK product; and the crude MIBK product enters the separator, the first rectifying column, the second rectifying column, the dehydration column according to one of the objects of the present application, and the fourth rectifying column in sequence to obtain MIBK.

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

[0062] In the present application, the dehydration column condenser is arranged at the top of the dehydration column, and the liquid collecting pan is arranged in the upper part, so that the water phase pump and the oil phase pump in the prior art can be omitted. In the present application, a plurality of devices are organically combined and functionally merged, which can save the land occupation and investment, reduce the energy consumption of the device, break through the limitation of the pump in the prior art, increase the flow, further enhance the chromatography effect, improve the product quality and production efficiency, and make the control more stable and convenient to operate. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 The dehydration column is the prior art;

[0064] Figure 2 The dehydration column is one of the objects of the present application;

[0065] Figure 3MIBK rectification device for the third purpose of the present application;

[0066] Figure 4 System for synthesizing MIBK for the fourth purpose of the present application;

[0067] Figure 5 Front view structural schematic diagram of the reactor in the system for synthesizing MIBK for the fourth purpose of the present application;

[0068] Figure 6 Front view structural schematic diagram of the gas-liquid distributor and the left feed nozzle, the right feed nozzle, the hydrogen feed pipe, the feed baffle in the system for synthesizing MIBK for the fourth purpose of the present application;

[0069] Figure 7 Top view structural schematic diagram of the distribution plate, the downcomer and the left feed nozzle, the right feed nozzle in the system for synthesizing MIBK for the fourth purpose of the present application;

[0070] Figure 8 For Figure 6 Partial enlarged schematic diagram of A in the middle;

[0071] Figure 9 Partial top view structural schematic diagram of the heat exchange pipe, the pipe bridge center and the second tube plate in the system for synthesizing MIBK for the fourth purpose of the present application;

[0072] Figure 10 Front view structural schematic diagram of the prior art fixed bed reactor with tubes.

[0073] In the 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 pipe; 9-pipe bridge center; 10-second tube plate;

[0075] 11-dehydration column condenser; 12-liquid collection tray; 13-riser; 14-baffle. DETAILED DESCRIPTION

[0076] The invention will be further described with reference to the drawings.

[0077] The present invention relates to a dehydration column, such as Figure 2As shown, the dehydration tower comprises a dehydration tower body, a dehydration tower condenser 11 arranged at the top of the dehydration tower body, and a liquid collecting tray 12 arranged horizontally in the upper portion of the dehydration tower body; an upcomer 13 is arranged upwardly on the liquid collecting tray 12, the upcomer 13 is a through pipe penetrating upwardly and downwardly, a baffle 14 is arranged at the top of the upcomer 13, and the bottom of the upcomer 13 is communicated with the liquid collecting tray 12. Specifically, the liquid collecting tray 12 is in the shape of a disc, and the outer edge of the liquid collecting tray 12 is tightly and sealingly connected with the inner wall of the dehydration tower body. An upcomer 13 extending upwardly is arranged at the center of the liquid collecting tray 12, and the upcomer 13 serves as a gas phase passage. The baffle 14 is arranged at the top of the upcomer 13 to prevent the condensed liquid from entering the upcomer 13 and further dropping onto the packing in the lower section of the dehydration tower body.

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

[0079] The height of the upcomer 13 determines the height of the condensed liquid level on the liquid collecting tray 12, and since the inner diameter of the dehydration tower body is determined, the height of the condensed liquid level on the liquid collecting tray 12 determines the volume of the condensed liquid that can be accommodated by the liquid collecting tray 12. In a preferred embodiment of the present application, the height of the upcomer 13 is 1 / 50-1 / 10, preferably 1 / 25-2 / 25 of the height of the dehydration tower body. It should be noted that the volume of the condensed liquid refers to the volume of the space between the liquid collecting tray 12 and the horizontal height of the upper edge of the upcomer 13 in the dehydration tower body, and the volume of the upcomer 13 is excluded.

[0080] In a preferred embodiment of the present application, the distance between the top surface of the riser pipe 13 and the dehydration tower condenser 11 is preferably 0.3-2 m, more preferably 0.4-1 m. It should be noted that the distance herein refers to the distance between the top surface of the riser pipe 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 liquid phase by the dehydration tower condenser 11, it falls into the liquid collection tray 12 under the action of gravity, and is collected and chromatographed on the liquid collection tray 12. Preferably, the condensation temperature of the dehydration tower condenser 11 is 40-82°C, more preferably 40-50°C. The lower the condensation temperature, the more conducive to the separation of the two phases. The dehydration tower condenser 11 can use the tower top condenser commonly used in the prior art, preferably a spiral plate condenser, or a general shell-and-tube heat exchanger, which can be over-cooled by liquid sealing through the liquid phase return line.

[0081] In a preferred embodiment of the present application, the baffle 14 is connected to the riser pipe 13 by at least two support members. The at least two support members are preferably arranged at equal intervals. Specifically, the support members can be support rods, the lower ends of which are connected to the upper edge of the riser pipe 13. The horizontal projection of the baffle 14 covers the horizontal projection of the riser pipe 13, i.e. the position and cross-sectional area of the baffle 14 can block the top end outlet of the riser pipe 13. The baffle 14 can be arranged in the shape of an umbrella, a semicircle, a triangle, a square, etc., preferably in the shape of an umbrella or a semicircle, which is beneficial for processing and manufacturing, and also facilitates the downward movement of the condensed liquid. During the upward movement of the gas phase, it cannot continue to move upward when encountering the baffle 14. Since the baffle 14 and the riser pipe 13 are only connected by support rods, the gas phase will move along the lower surface of the baffle 14 towards the pipe wall until it continues to move upward when there is no baffle 14 above, and finally rises to the dehydration tower condenser 11.

[0082] In a preferred embodiment of the present application, the dehydration tower body is provided with a gas phase feeding port in the middle and a tower kettle outlet at the bottom. Specifically, the reacted gas phase mixture enters the dehydration tower body from the gas phase feeding port. The gas phase mixture entering the dehydration tower body moves upward, enters the dehydration tower condenser 11 through the riser 13 in the middle of the liquid collecting pan 12. After being condensed into liquid phase, it falls into the liquid collecting pan 12 under the action of gravity, is collected on the liquid collecting pan 12 and is chromatographed. The condensed liquid of the gas phase mixture mainly includes about 15-40% water, 5-30% isopropyl alcohol, 30-60% MIBK and less than 2% acetone, where the percentage refers to the mass percentage. Among them, water and MIBK are completely insoluble, isopropyl alcohol is soluble in water and MIBK, and acetone is also soluble in water and oil phases. Therefore, the condensed liquid on the liquid collecting pan 12 will form water phase and oil phase after standing, and isopropyl alcohol will be dissolved in both phases. The oil phase includes methyl isobutyl ketone, isopropyl alcohol 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 the condensed liquid on the liquid collecting pan 12 needs to be allowed to stand for a certain period of time, so that the liquid phase can be well stratified. Preferably, the standing time of the condensed liquid is 10-250 min, more preferably 30-180 min.

[0083] After standing, the outlet can be taken. The dehydration tower body is provided with an oil phase outlet and a water phase outlet on both sides, both of which are higher than the liquid collecting pan 12. Except water which is taken out through the water phase outlet, the other three substances are taken out through the oil phase outlet. Preferably, a water phase level gauge is arranged on the pipeline of the water phase outlet; an oil phase level gauge is arranged on the pipeline of the oil phase outlet. More preferably, the pipeline of the oil phase outlet is connected with an oil phase separation tower and a light component storage tank respectively, and is connected with a reflux pipeline at the same time, part of the taken out oil phase is refluxed into the dehydration tower body, and the inlet of the reflux pipeline is arranged below the liquid collecting pan in the dehydration tower body. In this embodiment, the acetone tower is the oil phase separation tower.

[0084] In this embodiment, as Figure 2As shown, the water phase is discharged to the wastewater tower through the water phase level gauge, and the discharge rate can be adjusted by adjusting the level gauge. Similarly, the oil phase is discharged through the oil phase level gauge. Unlike the water phase discharge, the oil phase discharge is divided into three paths: under the action of gravity, one path goes to the acetone tower (i.e., the oil phase separation tower) to separate acetone and isopropyl alcohol, another path goes to the light component tank, and the rest flows back into the dehydration tower body. It should be noted that the inlet of the reflux pipeline is located below the liquid collecting pan 12 in the dehydration tower body. Since the liquid collecting pan 12 is located relatively high, it can directly flow back to the dehydration tower body under the action of gravity without the aid of a pump. Similarly, the water phase discharge, acetone tower discharge, and light component tank discharge also utilize the gravity difference and do not require the aid of a pump. After the remaining oil phase flows back to the dehydration tower body, it passes through the packing layer downward and is discharged from the dehydration tower kettle to enter the subsequent fourth rectifying tower E4. It should be noted that the dehydration tower kettle can be heated, and the liquid can be re-vaporized, condensed, and chromatographically refluxed, which is beneficial to further improving the purity of the product. The dehydration tower of the present application integrates the condenser, reflux tank, and two discharge pumps in the prior art, and only requires a dehydration tower body, a dehydration tower condenser 11 located at the upper part thereof, and a liquid collecting pan 12, which are combined to form a dehydration tower.

[0085] At present, the largest MIBK device in China is only 15,000 tons, and if the traditional dehydration process is used, the flow rate of the oil phase pump and the water phase pump at the top of the tower is less than 1 m 3 / h, and even if the smallest oil phase pump and water phase pump are purchased, their flow rate is at least 3-5 m 3 / h, so only the minimum reflux can be set to meet the normal operation of the pump. However, during the process of returning to the dehydration tower with the minimum reflux, the minimum reflux line of the pump will return to the chromatograph, which is because the chromatograph in the prior art is an external tank, and the pump operates at a small flow rate for a long time, which is low in efficiency and poor in chromatographic effect, and finally the quality of the product is also affected. The dehydration tower of the present application breaks through the limitations of the pump in the prior art and uses gravity to control the flow rate, solving the problem of controlling the flow rate with a pump in the prior art, which saves land occupation and investment, reduces device energy consumption, breaks through the limitations of the pump in the prior art, further enhances the chromatographic effect, controls more stably, and is more convenient to operate.

[0086] The present application 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, enters the dehydration tower condenser 11 after passing through the riser 13 in the middle of the liquid collecting pan 12, is condensed into a liquid phase, falls into the liquid collecting pan 12 under the action of gravity, and is collected and chromatographed on the liquid collecting pan 12. Preferably, the condensation temperature of the dehydration tower condenser 11 is 40-82℃, more preferably 40-50℃; and / or the pressure drop of the dehydration tower condenser 11 is not greater than 20 kpa.

[0087] The condensed liquid collected on the liquid collecting tray 12 forms an oil phase on top and a water phase on the bottom after standing. Preferably, the water phase is controlled to be withdrawn by the water phase level controller; the oil phase is controlled to be withdrawn by the oil phase level controller and is divided into three paths: one path goes to the oil phase separation, another path goes to the light component storage tank, and the rest goes back to the dehydration tower body. More preferably, the standing time of the condensed liquid collected on the liquid collecting tray 12 is 10-250 min, preferably 30-180 min; and / or 10-20% of the oil phase withdrawal goes to the oil phase separation tower, 5-20% goes to the light component storage tank, and the rest is refluxed through the reflux pipeline. It should be noted that the percentages here are volume percentages, because the withdrawal is controlled by the level controller. Specifically, in the preferred embodiment, 10-20% of the oil phase withdrawal goes to the acetone tower, 5-20% goes to the light component storage tank, and the rest is refluxed through the reflux pipeline. Figure 2 The condensed liquid collected on the liquid collecting tray 12 forms an oil phase on top and a water phase on the bottom after standing. Preferably, the water phase is controlled to be withdrawn by the water phase level controller; the oil phase is controlled to be withdrawn by the oil phase level controller and is divided into three paths: one path goes to the oil phase separation, another path goes to the light component storage tank, and the rest goes back to the dehydration tower body. More preferably, the standing time of the condensed liquid collected on the liquid collecting tray 12 is 10-250 min, preferably 30-180 min; and / or 10-20% of the oil phase withdrawal goes to the oil phase separation tower, 5-20% goes to the light component storage tank, and the rest is refluxed through the reflux pipeline. It should be noted that the percentages here are volume percentages, because the withdrawal is controlled by the level controller. Specifically, in the preferred embodiment, 10-20% of the oil phase withdrawal goes to the acetone tower, 5-20% goes to the light component storage tank, and the rest is refluxed through the reflux pipeline.

[0088] The present application also relates to a MIBK rectification device, as shown in Figure 3 from left to right, which includes a first rectification tower E1, a second rectification tower E2, a third rectification tower, and a fourth rectification tower E4. It should be noted that the third rectification tower is the dehydration tower of one of the purposes of the present application. The reacted MIBK crude product and the circulating gas are condensed, separated at low temperature, and enter the first rectification tower E1. The unreacted acetone is separated in the second rectification tower E2. The light component isopropyl alcohol and water are separated in the third rectification tower (i.e. the aforementioned dehydration tower). The pure MIBK product is obtained at the top of the fourth rectification tower E4. The first rectification tower E1, the second rectification tower E2, and the fourth rectification tower E4 of the present application can adopt the conventional design of the existing MIBK synthesis rectification device.

[0089] The present application also relates to a MIBK synthesis system, as shown in Figure 4 which includes a reactor, a separator, and the aforementioned rectification device in sequence. In one of the preferred embodiments of the present application, as shown in Figure 5 from bottom to top, the reactor includes a first tube plate, a heat exchange tube bundle, a second tube plate 10, a gas-liquid distributor, a feed pipe nozzle provided on the side wall of the reactor, and a hydrogen gas feed pipe 6. From bottom to top, the reactor includes a first tube plate, a heat exchange tube bundle, a second tube plate 10, a gas-liquid distributor, a feed pipe nozzle provided on the side wall of the reactor, and a hydrogen gas feed pipe 6. Figure 5As can be seen, the hydrogen feeding pipe 6 is arranged at the top of the reactor, and the gas phase enters the reactor through the hydrogen feeding pipe 6. The feeding pipe nozzles include a left feeding pipe nozzle 1 and a right feeding pipe nozzle 2, which are arranged at the same height on the opposite sides of the reactor. The liquid phase enters the reactor through the left feeding pipe nozzle 1 and the right feeding pipe nozzle 2. In the vertical direction, the lower edge of the left feeding pipe nozzle 1 and the lower edge of the right feeding pipe nozzle 2 are not lower than the height of the distribution plate 5. The gas-liquid distributor is horizontally arranged in the reactor and 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 the outer edge of the distribution plate 5 and the inner wall of the reactor are tightly fitted.

[0090] The gas-liquid distributor includes a distribution plate 5, a lower liquid hole 7 arranged on the distribution plate 5, and a gas falling pipe 4 arranged on the distribution plate 5 and extending upward. The gas falling pipe 4 is vertically arranged on the upper surface of the distribution plate 5. The gas falling pipe 4 is through from top to bottom (i.e., the lower end of the gas falling pipe 4 is a through hole on the distribution plate 5, and the upper end and the lower end of the gas falling pipe 4 are unobstructed, forming a through pipe), serving as a gas phase passage. The lower liquid hole 7 is through from top to bottom, serving as a liquid phase passage.

[0091] In a preferred embodiment of the present application, as shown in Figures 6 to 8 The distribution plate 5 is in the form 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 gas falling pipes 4 extend upward vertically. The gas falling pipes 4 are preferably uniformly distributed on the distribution plate 5. Between the gas falling pipes 4 on the distribution plate 5, a lower liquid hole 7 is arranged. The lower liquid hole 7 is preferably uniformly distributed on the distribution plate 5, and more preferably, the lower liquid hole 7 is arranged between two adjacent gas falling pipes 4.

[0092] In order to better realize the uniform entry of the gas-liquid two-phase into the pipe, in one preferred embodiment of the present application, the flow rate of the gas phase through the gas falling pipe 4 is not greater than 10 m / s, or the pressure drop when the gas phase passes through the gas falling pipe 4 is not more than 0.1 kPa. Preferably, the flow rate of the gas phase through the gas falling pipe 4 is 0.001-10 m / s, and more preferably, 0.01-5 m / s; or the pressure drop when the gas phase passes through the gas falling pipe 4 is preferably 0.01-0.08 kPa. More preferably, the inner diameter of the gas falling pipe 4 is preferably 15-50 mm, and more preferably, 19-44 mm. Furthermore, the height of the gas falling pipe 4 is 10-50 cm, and preferably, 20-30 cm. The ratio of the center distance between two adjacent gas falling pipes 4 to the inner diameter of the gas falling pipe 4 is 1.2-1.5:1.

[0093] In order to make the gas-liquid two-phase flow into the tube uniformly, in one preferred embodiment of the present application, the shape of the lower liquid hole 7 can be any one of a circle, a square, a diamond, a pentagon, and a hexagon. Further, the preferred shape of the lower liquid hole 7 is a circle, and the preferred inner diameter of the lower liquid hole 7 is 1-6 mm, preferably 0.5-5 mm. The area of the lower liquid hole 7 is related to the height of the gas downcomer 4 to ensure that the gas-liquid two-phase flow into the tube uniformly. It should be noted that Figure 3 The circular lower liquid hole 7 does not constitute a limitation to the present application, 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 0.1-3 m / s, preferably 0.2-0.6 m / s. Further, the ratio of the center distance between two adjacent lower liquid holes 7 to the inner diameter of the gas downcomer 4 is 1.2-1.5:1.

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

[0095] In 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 the acetone enters the reactor and is deflected by the feed baffle 3, 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 in the middle of the downcomer 4 is automatically controlled by the flow meter. The liquid phase acetone moves downward from the downcomer 4. By reasonably setting the inner diameter of the downcomer 4, the flow rate of the hydrogen moving downward can be controlled. Similarly, by setting the area of the downcomer 7, the flow rate of the acetone moving downward can be controlled to match 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 downcomer 7 can be determined, and thus the acetone can flow downward uniformly and match the flow rate of the gas phase moving downward.

[0096] The distributor is provided below with a tube plate in the form of a disc, preferably a circular disc; the outer edge of the tube plate is connected to the inner wall of the reactor and is arranged horizontally, and the outer edge of the tube plate is tightly attached to the inner wall of the reactor. As shown in Figure 4 , the tube plate includes a second tube plate 10 adjacent to the lower edge of the gas-liquid distributor and a first tube plate adjacent to the bottom of the reactor. The first tube plate and the second tube plate 10 are uniformly provided with a plurality of through holes capable of accommodating heat exchange tube bundles, the heat exchange tube bundles are composed of a plurality of vertically arranged heat exchange tubes 8, and the arrangement mode of the through holes is the same as that of the heat exchange tubes 8 to respectively pass through a plurality of the heat exchange tubes 8. The distance between the distribution plate 5 and the second tube plate 10 is 5-150 mm, preferably 50-100 mm. The inner diameter of the heat exchange tube 8 is 15-50 mm, preferably 19-44 mm. The ratio of the center distance between two adjacent heat exchange tubes 8 to the inner diameter of the heat exchange tube 8 is 1.2-1.5:1.

[0097] A plurality of the heat exchange tubes 8 and a plurality of the downcomers 7 vertically correspond one by one, and the number of the heat exchange tubes 8 is the same as that of the downcomers 7. Preferably, the downcomer 7 and the heat exchange tube 8 are coaxially arranged, the inner diameter of the downcomer 7 is smaller than that of the corresponding heat exchange tube 8, and the center of the downcomer 7 orthogonally projected on the horizontal plane coincides with the center of the heat exchange tube 8 orthogonally projected on the horizontal plane. The liquid phase moving downward through the downcomer 7 uniformly drops into the heat exchange tube 8 below.

[0098] The part of the tube plate connecting adjacent heat exchange tubes 8 is a tube bridge. As shown in Figure 9As shown, the heat exchange tubes 8 are arranged in a regular triangle shape. Taking three adjacent heat exchange tubes 8 as an example, the centers of the three heat exchange tubes 8 are connected to form a triangle region, and the center of the triangle region is the tube bridge center 9. Preferably, the tube bridge center 9 is vertically corresponding to the downcomer 4; more preferably, each tube bridge center 9 corresponds to one downcomer 4. That is, the center of the downcomer 4 on the horizontal plane is coincident with the tube bridge center 9. It should be noted that, since the gas phase is easy to change direction, the number of downcomers 4 does not necessarily equal to the number of heat exchange tubes 8, and the center of the downcomer 4 on the horizontal plane does not necessarily coincide with the tube bridge center 9. The center of the downcomer 4 on the horizontal plane coincides with the tube bridge center 9, which is only an exemplary description and does not constitute a new limitation of the present application. Similarly, Figure 5 The arrangement of the plurality of heat exchange tubes 8 on the tube plate is also only an exemplary description, and does not constitute a limitation of the arrangement of the heat exchange tubes 8. Other polygonal arrangements are also possible.

[0099] The hydrogen and acetone flow downward uniformly from the downcomer 4 and the liquid outlet 7, respectively. The acetone enters the heat exchange tubes 8, and the hydrogen also enters the heat exchange tubes 8. This is because, although the center of the downcomer 4 on the horizontal plane is coincident with the tube bridge center 9, due to the blockage of the tube bridge, part of the hydrogen above the tube bridge cannot continue to move downward along the tube bridge, so part of the hydrogen above the tube bridge also changes direction and enters the heat exchange tubes 8 near the tube bridge center 9 to continue to move downward. The hydrogen is uniformly moved downward into the heat exchange tubes 8 through the downcomer 4, and the acetone on the distribution plate 5 is uniformly moved downward into the heat exchange tubes 8 through the liquid outlet 7, so as to ensure that the gas-liquid two-phase uniformly enters each heat exchange tube 8. The gas-liquid two-phase reacts under the catalysis of the catalyst in the heat exchange tubes 8 to obtain MIBK.

[0100] Other parts of the reactor for synthesizing MIBK according to the present application can adopt conventional designs of the reactors for synthesizing MIBK in the prior art.

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

[0102] Example 1

[0103] In one preferred embodiment of the present application, the downcomer 4 is arranged in the form of a regular triangle, and the tube bridge center 9 is vertically corresponding to the downcomer 4. The downcomer 4 is arranged in the form of a regular triangle, and the tube bridge center 9 is vertically corresponding to the downcomer 4, which is only an exemplary description and does not constitute a new limitation of the present application. Figures 2 to 9The system provided with the reactor, the separator, the first rectifying tower E1, the second rectifying tower E2, the dehydration tower and the fourth rectifying tower E4 of the structure shown is used 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 collecting tray 12 and the lower edge of the dehydration tower condenser 11 is 3000 mm. The middle part of the collecting tray 12 is provided with an upwardly extending riser pipe 13, which has a diameter of 250 mm and a height of 2500 mm. The dehydration process is as follows: after the reaction gas phase mixture is vaporized (the flow rate is about 1000 kg / h), it moves upwards along the riser pipe 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℃. After the gas phase mixture is condensed, the condensed liquid is obtained, which falls to the collecting tray 12 under the action of gravity. The residence time of the condensed liquid in the collecting tray 12 is 2.79 h. In addition to water which is extracted by the water phase (69 kg / h), the remaining three substances are extracted by the oil phase (931 kg / h), of which 15% is discharged to the acetone separation tower, 15% is discharged to the light component storage tank, and the remaining oil phase is returned 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 heat exchange tube 8 has an outer diameter of 38 mm, an inner diameter of 32 mm and a height of 9 m; the center distance between adjacent two heat exchange tubes 8 is 47.5 mm. The lower end of the heat exchange tube is arranged in the first tube plate, and the upper end is arranged in the second tube plate 10. The distribution plate 5 of the gas-liquid distributor of the application is arranged at a position 100 mm above the second tube plate 10, and the distribution plate 5 is provided with 1216 downwardly extending downcomers 4, the downcomer 4 has an outer diameter of 38 mm, an inner diameter of 32 mm and a height of 30 cm, and the center distance between adjacent two downcomers 4 is 47.5 mm. A plurality of the downcomers 4 and a plurality of the tube bridge centers 9 are vertically corresponding one by one. The distribution plate 5 is provided with 1216 liquid outlet holes 7, the liquid outlet hole 7 has an inner diameter of 3 mm, and the center distance between adjacent two liquid outlet holes is 47.5 mm. A plurality of the heat exchange tubes 8 and a plurality of the liquid outlet holes 7 are vertically corresponding and 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 liquid outlet hole 7 is 9 m / s. The feed pipe nozzle is arranged above the distribution plate 5, which includes a left feed pipe nozzle 1 and a right feed pipe nozzle 2, and the two are arranged at the same height on the side surface of the reactor and are oppositely arranged. The diameter of the feed pipe nozzle is 80 mm. The feed baffle 3 is divided into two parts, which are arranged between the feed pipe nozzle and the downcomer closest to the inner wall of the reactor; the distance between the middle part of the feed baffle 3 and the feed pipe 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 existing dehydration tower shown (1.5m diameter, 36m height) removes water and isopropanol at the top. The conventional process is as follows: the material at the top of the dehydration tower enters the dehydration tower condenser and is condensed into a liquid phase, which enters the dehydration tower reflux tank. The reflux tank (1500mm diameter, 3m length) serves as a reflux buffer and also performs chromatography of the oil phase (931kg / h) and the aqueous phase (69kg / h). The aqueous phase is pumped to the wastewater tower, and the oil phase is pressurized by a pump and divided into three streams: one stream is returned to the tower for reflux, one stream is pumped to the acetone tower, and one stream is sent to the light component tower.

[0107] like Figure 10 The prior art shown is a tubular fixed-bed reactor. The upper part of the reactor is sequentially equipped with a liquid-holding distributor, structured packing, and honeycomb; the lower part of the reactor is a wedge-shaped support plate, and the catalyst is filled inside the tubes and on the support plate. The distributor design of the reactor is complex.

[0108] Compared with the prior art of Comparative Example 1, the dehydration tower of Embodiment 1 of the present invention can eliminate the need for the water phase pump and oil phase pump in the prior art, saving 36m² of floor space. 2 This reduces the energy consumption of the equipment, saving 1-2 kW of electricity per hour. At the same time, it overcomes the limitations of existing pumps, increasing the flow rate and further enhancing the chromatography effect, improving product quality and production efficiency, while also making control more stable and easier to operate.

[0109] Furthermore, the gas-liquid distributor of Embodiment 1 of the present invention enables the gas and liquid phases to enter the heat exchange tubes more uniformly. This is because existing distributors use random packing and honeycomb packing below, which inevitably leads to wall effects and channeling, and the smaller the packing height, the more pronounced the wall effect. The gas-liquid distributor of Embodiment 1 of the present invention ensures a consistent flow rate of liquid phase dripping from each liquid outlet 7 through the uniform distribution of liquid level and static pressure head on the distribution plate 5, thus ensuring a consistent flow rate of liquid phase entering each heat exchange tube 8. Simultaneously, a downcomer 4 is provided to ensure that the gas phase can pass uniformly through the distribution plate 5 and enter each heat exchange tube 8 uniformly. In Comparative Example 1, the selectivity of the MIBK synthesis reaction is 94%, and the catalyst lifetime is 7200 hours. In Embodiment 1, because the gas and liquid phases enter the heat exchange tubes 8 uniformly, the selectivity of the reaction is improved to 94.2%; on the other hand, the hot spot temperature is easier to control, and the reactor is less prone to temperature runaway. Furthermore, the uniform entry of the gas and liquid phases into the heat exchange tube 8 will extend the catalyst's lifespan. In this embodiment, the catalyst's lifespan can reach 8000 hours.

Claims

1. A dehydration tower, characterized in that: The dehydration tower includes a tower body, a condenser located at the top of the tower body, and a collection tray horizontally positioned within the upper part of the tower body. An upward-facing riser pipe is installed on the collection tray; the riser pipe is a through pipe with a baffle at its top and its bottom connected to the collection tray. A gas inlet is located in the middle of the tower body, and a bottom outlet is located at the bottom. Oil and water phase outlets are located on both sides of the tower body, both above the collection tray, with the oil phase outlet higher than the water phase outlet. A water phase interface gauge is installed on the water phase outlet pipeline; an oil phase interface gauge is installed on the oil phase outlet pipeline. The oil phase outlet pipeline is connected to an oil phase separation tower and a light component storage tank, and simultaneously to a reflux pipeline, returning a portion of the extracted oil phase to the tower body. The reflux pipeline inlet is located below the collection tray within the tower body.

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

3. The dehydration tower according to claim 2, characterized in that: The height of the air riser is 1 / 25 to 2 / 25 of the height of the dehydration tower body.

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

5. The dehydration tower according to claim 4, characterized in that: The distance between the top surface of the riser pipe and the condenser of the dehydration tower is 0.4–1 m; and / or The condensation temperature of the dehydration tower condenser is 40–50°C.

6. 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 pipe, and the baffle is connected to the liquid collection tray by at least two support members; the orthographic projection of the baffle on the horizontal plane covers the orthographic projection of the riser pipe on the horizontal plane.

7. The dehydration tower according to claim 6, characterized in that: The baffle can be any one of the following shapes: umbrella-shaped, semi-circular, triangular, or square.

8. The dehydration tower according to claim 7, characterized in that: The baffle is umbrella-shaped or semi-circular.

9. The dehydration method of the dehydration tower according to any one of claims 1 to 8, characterized in that, Includes the following steps: The reaction gas mixture enters the dehydration tower body through the gas inlet. The gas mixture moves upward and enters the dehydration tower condenser after passing through the riser pipe in the middle of the collection tray. It is then condensed into a liquid phase and falls into the collection tray under gravity. The liquid phase is collected on the collection tray and subjected to chromatography. The condensate liquid phase collected on the collection tray forms an oil phase at the top and a water phase at the bottom after settling. The oil phase is controlled by the oil phase interface gauge and is divided into three paths: one path goes to the oil phase separation, another path goes to the light component storage tank, and the remainder flows back into the dehydration tower body.

10. The dehydration method according to claim 9, characterized in that: The condensation temperature of the dehydration tower condenser is 40–82°C; and / or the pressure drop of the dehydration tower condenser is not greater than 20 kPa.

11. The dehydration method according to claim 10, characterized in that: The condensation temperature of the dehydration tower condenser is 40–50°C.

12. The dehydration method according to claim 9, characterized in that: The aqueous phase is extracted under the control of the aqueous phase interface gauge.

13. The dehydration method according to claim 9, characterized in that: The condensate collected on the collection tray is allowed to stand for 10–250 minutes; and / or Of the extracted oil phase, 10-20% 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.

14. The dehydration method according to claim 13, characterized in that: The condensate collected on the collection tray should be left to stand for 30 to 180 minutes.

15. A distillation apparatus, characterized in that: It includes a first distillation column, a second distillation column, a dehydration column according to any one of claims 1 to 8, and a fourth distillation column connected in sequence.

16. A system for synthesizing MIBK, characterized in that: The system comprises a reactor, a separator, and the distillation apparatus of claim 15, connected in sequence.

17. The system according to claim 16, characterized in that: The reactor, from bottom to top, includes a first tube sheet, a heat exchange tube bundle, a second tube sheet, a gas-liquid distributor, a feed nozzle located on the side wall of the reactor, and a hydrogen feed pipe located at the top of the reactor.

18. The system according to claim 17, characterized in that: The gas-liquid distributor includes a distribution plate, a liquid outlet on the distribution plate, and a gas descending pipe that is located on the distribution plate and extends upward; wherein the distribution plate is horizontally arranged.

19. The system according to claim 18, characterized in that: The distribution plate is flat; and / or The downdraft is multiple; and / or There are multiple liquid discharge holes.

20. The system according to claim 19, characterized in that: The distribution plate is disc-shaped; and / or Multiple gas downpipes are evenly distributed on the distribution plate; and / or The plurality of liquid discharge holes are evenly distributed on the distribution plate.

21. The system according to claim 20, characterized in that: The distribution plate is disc-shaped; and / or The liquid outlet is located between two adjacent gas downpipes.

22. The system according to claim 18, characterized in that: The inner diameter of the downdraft is 15–50 mm; and / or The height of the downdraft is 10–50 cm; and / or The shape of the liquid outlet can be any one of the following: circular, square, rhomboid, pentagonal, or hexagonal.

23. The system according to claim 22, characterized in that: The inner diameter of the downdraft is 19–44 mm; and / or The height of the downdraft is 20–30 cm; and / or The liquid outlet is circular.

24. The system according to claim 23, characterized in that: The inner diameter of the liquid discharge hole is 1 to 6 mm.

25. The system according to any one of claims 18 to 24, characterized in that: The ratio of the center-to-center distance between two adjacent downdrafts to the inner diameter of the downdraft is 1.2 to 1.5:1; and / or The ratio of the center-to-center distance between two adjacent liquid outlets 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 sheet is 5 to 150 mm.

26. The system according to claim 25, characterized in that: The distance between the distribution plate and the second tube sheet is 50-100 mm.

27. The system according to claim 18, characterized in that: The heat exchange tube bundle includes a plurality of vertically arranged heat exchange tubes, each of which is vertically corresponding to a plurality of liquid outlets; and / or In the horizontal direction, a feed baffle is vertically provided between the feed nozzle and the downdraft pipe. The outer edge of the feed baffle is fixed to the side wall of the reactor, and its lower edge is higher than the distribution plate. The orthogonal projection of the feed baffle on the side wall of the reactor covers the feed nozzle.

28. The system according to claim 27, characterized in that: 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 downdraft; and / or The horizontal distance between the middle of the feed baffle and the feed nozzle is 1 / 4 to 1 / 4 of the diameter of the feed nozzle.

29. A method for synthesizing MIBK, characterized in that: The system according to any one of claims 18 to 28 is used. Acetone enters the reactor through the feed nozzle, and hydrogen enters the reactor through the hydrogen feed pipe. Acetone and hydrogen enter the heat exchange tube bundle through the liquid outlet and the downcomer, respectively, to react and obtain crude MIBK product. The crude MIBK product sequentially enters the separator, the first distillation column, the second distillation column, the dehydration column, and the fourth distillation column to obtain MIBK.

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