A system and method for producing isophorone and mesityl oxide by a gas phase condensation method

Abstract

The application discloses a system for producing isophorone and mesityl oxide by a gas phase condensation method, characterized in that a ketone vaporization tower is provided with a ketone inlet, the ketone vaporization tower is sequentially connected with a first ketone gas phase condensation reactor and a second ketone gas phase condensation reactor, the second ketone gas phase condensation reactor is connected with a ketone recovery tower through a ketone heat exchanger, the ketone recovery tower is connected with the ketone vaporization tower, the ketone recovery tower is connected with a decanter through a ketone recovery tower bottom cooler, a water phase outlet of the decanter is connected with a waste water tower, an oil phase outlet of the decanter is connected with a light component removal tower, the light component removal tower is connected with a mesityl oxide refining tower, the light component removal tower is connected with a mesitylene refining tower, a top of the mesitylene refining tower is provided with a mesitylene product outlet, the mesitylene tower is connected with an isophorone refining tower, and the isophorone refining tower is provided with an isophorone product outlet.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical industry, and particularly relates to a system and method for producing isophorone and isopropylidene acetone by a gas phase condensation method. BACKGROUND

[0002] With the vigorous development of the chemical new material industry in China, the degree of chemical fine processing is increasingly deepened, and new materials with special properties such as isophorone diisocyanate (IPDI) and isophorone diamine (IPDA) have attracted widespread attention from the society.

[0003] At present, the main methods for generating isophorone are as follows: 1. isopropylidene acetone method. The isopropylidene acetone method is to use isopropylidene acetone and ethyl acetoacetate as raw materials to generate isophorone under the action of a catalyst at a low temperature and under normal pressure through dehydration and epoxidation processes. The isopropylidene acetone method for preparing isophorone has the characteristics of mild reaction conditions, simple process, and convenient operation, but the price of the raw materials is relatively high, which limits the large-scale production. 2. Liquid phase condensation method of acetone. Under the environment of high temperature, high pressure, and strong alkaline liquid catalyst, two molecules of acetone undergo condensation reaction to form one molecule of diacetone alcohol, and then the diacetone alcohol undergoes dehydration reaction to form isopropylidene acetone intermediate, and then the intermediate undergoes dehydration condensation with one molecule of acetone to form isophorone. This method has low catalyst cost and simple generation process, but the reaction is carried out at high temperature and high pressure, which has high requirements for equipment and low safety. The waste liquid after the reaction not only corrodes the equipment, but also pollutes the environment. 3. Gas phase condensation method of acetone. The gas phase condensation method is to generate isophorone by alcohol aldehyde condensation, dehydration, and conjugate addition under the condition of using solid alkali materials as catalysts. This method has the advantages of mild reaction conditions, normal pressure, easy separation of products, low emission, small pollution, less waste, and continuous production by using a fixed bed reactor.

[0004] Patent CN101633610 discloses a method for preparing alpha-isophorone. The reaction is carried out in a tubular reactor under supercritical conditions at a pressure of 8.0-20.0 MPa and a temperature of 280-320℃. The reaction pressure is high, the requirements for equipment are strict, the equipment investment is large, the control is difficult, and the product conversion rate is low. Patent CN107573227 discloses a device and method for preparing isophorone by gas phase condensation of acetone. The invention uses a new type of separation technology such as a partition wall column to separate the condensation reaction products of acetone. The first partition wall column adds an azeotrope to change the relative volatility of the components in the original solution for separation. The disadvantage is that another azeotrope is needed for separation, which increases the operation difficulty and energy consumption of the entire device, and increases the equipment investment. SUMMARY

[0005] The technical problem solved by the present application is to provide a system and method for producing isophorone and mesityl oxide by gas phase condensation, which has high conversion rate, simple separation process, does not need to add azeotrope, low reactor pressure, safety and environmental protection.

[0006] The technical solution adopted by the present application to solve the above technical problem is: a system for producing isophorone and mesityl oxide by gas phase condensation, comprising an acetone vaporization tower, a first acetone gas phase condensation reactor, a second acetone gas phase condensation reactor, an acetone recovery tower, a decanter, a wastewater tower, a light component removal tower, a mesityl oxide refining tower, a mesitylene refining tower and an isophorone refining tower, the upper part of the acetone vaporization tower is provided with a liquid phase acetone inlet, the gas outlet at the top of the acetone vaporization tower is connected with the top inlet of the first acetone gas phase condensation reactor through an acetone heat exchanger and an acetone superheater in sequence, the bottom outlet of the first acetone gas phase condensation reactor is connected with the bottom inlet of the second acetone gas phase condensation reactor through a cold acetone vaporizer, the top outlet of the second acetone gas phase condensation reactor is connected with the middle feeding port of the acetone recovery tower through the acetone heat exchanger, the gas outlet at the top of the acetone recovery tower is connected with the gas phase acetone inlet at the lower part of the acetone vaporization tower, the bottom discharge port of the acetone recovery tower is connected with the decanter through an acetone recovery tower bottom cooler, the water phase outlet of the decanter is connected with the middle feeding port of the wastewater tower, the top outlet of the wastewater tower is connected with the decanter, the oil phase outlet of the decanter is connected with the middle feeding port of the light component removal tower, the gas outlet at the top of the light component removal tower is connected with the mesityl oxide refining tower, the bottom of the mesityl oxide refining tower is provided with a mesityl oxide product outlet;

[0007] The bottom discharge port of the light component removal tower is connected with the middle feeding port of the mesitylene refining tower, the top of the mesitylene refining tower is provided with a mesitylene product outlet, the bottom discharge port of the mesitylene tower is connected with the middle feeding port of the isophorone refining tower, and the top of the isophorone refining tower is provided with an isophorone product outlet.

[0008] Further, the inlet pipelines of the first acetone gas phase condensation reactor and the second acetone gas phase condensation reactor are respectively connected with a steam pipeline and a compressed air pipeline.

[0009] Further, the first acetone gas phase condensation reactor and the second acetone gas phase condensation reactor are both adiabatic fixed bed reactors.

[0010] The present application also provides a method for producing isophorone and mesityl oxide by gas phase condensation using the above system, comprising the following steps:

[0011] (1) acetone vaporization tower

[0012] Fresh acetone is sent to the acetone feed buffer tank, pressurized, and then fed into the acetone vaporizer along with the gaseous acetone from the top of the acetone recovery column. The pressure of the acetone vaporizer is controlled at 0.15-0.5 MPaG. After the acetone is vaporized and the impurities are removed, the acetone gas with a mass concentration of 95% is obtained at the top of the column;

[0013] (2) The acetone gas obtained in step (1) is heated by the acetone heat exchanger, further heated by the acetone superheater, and then fed into the first gas-phase condensation reactor for reaction. The temperature of the gas-phase condensation reaction is controlled at 240-350°C, and the pressure is controlled at 0.05-0.4 MPaG. After the reaction is completed, the reaction product is sent to the second gas-phase condensation reactor for reaction. The temperature of the gas-phase condensation reaction is controlled at 240-350°C, and the pressure is controlled at 0.05-0.4 MPaG. After the reaction is completed, the reaction product is sent to the acetone heat exchanger for heat exchange and cooling, and then fed into the acetone recovery column;

[0014] (3) The pressure of the acetone recovery column is controlled at 0.25-0.6 MPaG, and the acetone in the reaction product is separated. The acetone solution with a mass concentration of 95% obtained at the top of the column is sent back to the acetone vaporizer for recycling. The water and organic impurities obtained at the bottom of the column are sent to the decanter;

[0015] (4) The pressure of the decanter is controlled at 0.05-0.8 MPaG, and the temperature is controlled at 40-90°C. The oil phase and the water phase are separated. The water phase containing 1-3 wt% of organic matter is sent to the waste water column, and the oil phase containing 3-5 wt% of water is sent to the light-removing column;

[0016] (5) The pressure of the waste water column is controlled at 0.05-0.5 MPaG. After separation, the azeotrope of water and isopropylidene acetone obtained at the top of the column is sent back to the decanter, and the waste water containing less than 1000 ppm of organic matter obtained at the bottom of the column is sent to the outside;

[0017] (6) The pressure of the light-removing column is controlled at 2-100 kPaA. After separation, the mixture composed of isopropylidene acetone and water (water 6%, isopropylidene acetone 94%) obtained at the top of the column is sent to the isopropylidene acetone refining column, and the mixture containing mesitylene, isophorone, and heavy oil obtained at the bottom of the column is sent to the mesitylene refining column;

[0018] (7) The top pressure of the isopropylidene acetone refining column is controlled at 20-100 kPaG. After separation, the azeotrope of isopropylidene acetone and water obtained at the top of the column is returned to the decanter, and the isopropylidene acetone product with a purity of 99.5 wt% is obtained at the bottom of the column;

[0019] (8) The pressure of the mesitylene refining column is controlled to be 2kPa-0.1MpaG, and after separation, the purity of the mesitylene product obtained from the top of the column is 99.5wt%, and the mixture composed of isophorone and heavy components (the proportion of isophorone is 91%, and the rest is heavy components) obtained from the bottom of the column is sent into the isophorone refining column;

[0020] (9) The pressure of the isophorone refining column is controlled to be 2kPa-0.1MpaG, and after separation, the purity of the isophorone product obtained from the top of the column is 99.9wt%, and the heavy components obtained from the bottom of the column are discharged to the outside.

[0021] Further, after the system runs for a period of time, when the single-pass conversion rate of acetone and the selectivity of isophorone and isopropylidene acetone decrease by 5%-10%, it indicates that the catalyst needs to be regenerated, and the specific steps are as follows: first, the reaction system is replaced with nitrogen, after the replacement is completed, the compressed air with a pressure of 0.2-0.3MPaG is heated to 350-400℃ by the regeneration gas heater, and then is respectively introduced into the first gas-phase condensation reactor and the second gas-phase condensation reactor at a flow rate of 5-15m / s, and after 30-50min, the introduction of the compressed air is stopped; then the steam with a pressure of 0.5MPaG is heated to 350-400℃ by the regeneration gas heater, and then is respectively introduced into the first gas-phase condensation reactor and the second gas-phase condensation reactor at a flow rate of 1-5m / s, and after continuous introduction for 3-6h, the introduction of the steam is stopped; the residual water is removed by continuously introducing the compressed air with a pressure of 0.2-0.3MPaG, which is heated to 350-400℃ by the regeneration gas heater, and the flow rate is controlled to be 5-15m / s, and after 30-50min, the introduction of the compressed air is stopped; nitrogen is continuously introduced to replace the air in the reaction system until the oxygen content in the analysis system is less than 0.5vt%, and then the regeneration process is completed. In the acetone gas-phase condensation reaction, carbon deposition will occur on the surface of the catalyst with the extension of the reaction time, which affects the conversion rate of the reaction and the selectivity of the product, therefore, the catalyst needs to be regenerated after the system runs for a period of time. The fresh regenerated air and water vapor are vaporized after being heated by the heater, and then are introduced into the reactor to carry out the decarburization reaction, under high temperature, the C deposited on the surface of the catalyst reacts with the water vapor, the impurities generated by the decarburization on the surface of the catalyst are taken away by the hot air, and after a period of regeneration, the regenerated reactor is put into use again.

[0022] Compared with the prior art, the advantages of the present application are that:

[0023] 1、The acetone vaporization tower separates the components by using the different relative volatilities of acetone and impurities. The acetone vaporization tower does not have a condenser, and the acetone enters the acetone heat exchanger in the form of gas phase, which is more energy-saving than entering the acetone heat exchanger in the form of liquid phase.

[0024] 2. The reactions that occur in the first and second acetone gas phase condensation reactors are:

[0025] Main reaction: 3 acetone → isophorone + 2 water;

[0026] Side reaction: 2 acetone → mesityl oxide + water;

[0027] 3 acetone → TMP + 3 water;

[0028] N acetone → C M + Y water (N = 4-8, M = 12-18, Y = 3-6), which is an exothermic reaction.

[0029] A fixed bed reactor is used, with cold acetone added in the middle of the two reactors in series to control the reaction temperature. Compared with a column reactor, the fixed bed reactor has a smaller volume, which reduces equipment investment and eliminates the need to pass a heat transfer medium through the reactor to control the temperature, which is more energy efficient and more efficient. A regeneration system is introduced in the reaction section. When the reaction conversion rate and product selectivity decrease, the catalyst can be regenerated. The catalyst regeneration method is simple and easy to implement, which prolongs the service life of the single-loaded catalyst and reduces the overall catalyst investment of the device.

[0030] 3. Acetone recovery column: The relative volatility difference between components is used to separate acetone from the reactants and recycle it to the reactor to improve the reaction conversion rate. The acetone recovery column does not have a condenser, and the gas phase is directly returned to the acetone vaporization column for acetone recovery, which saves energy consumption, increases the pressure of the acetone recovery column, and eliminates the need for an acetone compressor, which saves equipment investment.

[0031] 4. Reaction product decanter: The water phase and oil phase are separated according to the different solubilities of the reaction products. Compared with direct passage into a rectification column, this method saves investment and energy consumption.

[0032] 5. Light removal column: The purpose is to separate mesityl oxide, water, and other organic substances.

[0033] 6. Mesityl oxide column: Mesityl oxide forms an azeotrope with water, and the overhead product of the light removal column is introduced into the mesityl oxide column. The isophorone and water at the bottom of the mesityl oxide column are removed in the form of an azeotrope and introduced into the decanter. Compared with other methods of separating azeotropes, this method greatly saves energy consumption.

[0034] 7. Mesityl oxide column: A small amount of mesityl oxide is produced in the acetone gas phase condensation, which is removed from the top of the mesityl oxide column based on the relative volatility difference with other components.

[0035] In summary, the system and method for producing isophorone and isopropylidene acetone by gas phase condensation method of the present application does not need to introduce azeotrope again for separation of reaction products, and uses the different solubility of each product to separate first, and the acetone recovery tower is no longer provided with overhead condenser and reflux, so that the whole system is more energy-saving and efficient, and the equipment investment of the whole device is reduced. The regeneration system is introduced in the reaction part, the catalyst regeneration method is simple and easy to operate, the service life of the catalyst is prolonged, the catalyst investment of the device is reduced, and finally the single-pass conversion rate of acetone is 30-50%, and the selectivity of isophorone is 60-80%. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The structure of the system for producing isophorone and isopropylidene acetone by gas phase condensation method of the present application is shown in the figure, and each mark in the figure is as follows: 1-acetone vaporization tower, 2-acetone heat exchanger, 3-acetone superheater, 4-regeneration gas heater, 5-first acetone gas phase condensation reactor, 6-cold acetone vaporizer, 7-second acetone gas phase condensation reactor, 8-acetone recovery tower, 9-acetone recovery tower bottom cooler, 10-decanter, 11-waste water tower, 12-light removal tower, 13-isopropylidene acetone refining tower, 14-mesitylene refining tower, 15-isophorone refining tower. DETAILED DESCRIPTION

[0037] The present application will be further described in detail below in combination with the embodiments of the drawings. Specific embodiment one

[0039] The system for producing isophorone and isopropylidene acetone by gas phase condensation method, as shown in Figure 1As shown, including acetone vapor column 1, the first acetone gas phase condensation reactor 5, the second acetone gas phase condensation reactor 7, acetone recovery column 8, decanter 10, wastewater column 11, light removal column 12, isopropylidene acetone refining tower 13, mesitylene refining tower 14 and isophorone refining tower 15, the upper part of acetone vapor column 1 is provided with a liquid phase acetone inlet, the overhead outlet of acetone vapor column 1 is connected with the top inlet of the first acetone gas phase condensation reactor 5 through acetone heat exchanger 2 and acetone superheater 3 in turn, the bottom outlet of the first acetone gas phase condensation reactor 5 is connected with the bottom inlet of the second acetone gas phase condensation reactor 7 through cold acetone vaporizer 6, the top outlet of the second acetone gas phase condensation reactor 7 is connected with the middle inlet of acetone recovery column 8 through acetone heat exchanger 2, the overhead outlet of acetone recovery column 8 is connected with the gas phase acetone inlet of the lower part of acetone vapor column 1, the bottom outlet of acetone recovery column 8 is connected with decanter 10 through acetone recovery column bottom cooler 9, the water phase outlet of decanter 10 is connected with the middle inlet of wastewater column 11, the overhead outlet of wastewater column 11 is connected with decanter 10, the oil phase outlet of decanter 10 is connected with the middle inlet of light removal column 12, the overhead outlet of light removal column 12 is connected with isopropylidene acetone refining tower 13, the bottom of isopropylidene acetone refining tower 13 is provided with an isopropylidene acetone product outlet; the bottom outlet of light removal column 12 is connected with the middle inlet of mesitylene refining tower 14, the top of mesitylene refining tower 14 is provided with a mesitylene product outlet, the bottom outlet of mesitylene column is connected with the middle inlet of isophorone refining tower 15, and the top of isophorone refining tower 15 is provided with an isophorone product outlet.

[0040] In this specific embodiment, the inlet pipelines of the first acetone gas phase condensation reactor 5 and the second acetone gas phase condensation reactor 7 are respectively connected with steam pipelines and compressed air pipelines. Specific embodiment two

[0042] A method for producing isophorone and isopropylidene acetone by gas phase condensation using the system of specific embodiment one, comprising the following steps:

[0043] (1) acetone vapor column 1

[0044] Fresh acetone is sent into an acetone feed buffer tank, pressurized and then enters acetone vapor column 1 together with gas phase acetone from the top of acetone recovery column 8, the pressure of acetone vapor column 1 is controlled to be 0.15-0.5 MpaG, after acetone is vaporized and impurity components are removed, acetone gas with a mass concentration of 95% is obtained at the top;

[0045] (2) The acetone gas obtained in step (1) is heated by an acetone heat exchanger 2, further heated by an acetone superheater 3, and then enters a first gas phase condensation reactor for reaction, with the temperature of the gas phase condensation reaction controlled at 240-350°C and the pressure at 0.05-0.4 MPaG. After the reaction is completed, the reaction product is sent to a second gas phase condensation reactor for reaction, with the temperature of the gas phase condensation reaction controlled at 240-350°C and the pressure at 0.05-0.4 MPaG. The reaction product is sent to the acetone heat exchanger 2 for heat exchange and cooling, and then enters an acetone recovery column 8;

[0046] (3) The pressure of the acetone recovery column 8 is controlled at 0.25-6 MPaG, and the acetone in the reaction product is separated. The acetone solution with a mass concentration of 95% obtained at the top of the column is sent back to the acetone vaporization column 1 for recycling, and the water and organic impurities obtained at the bottom of the column are sent to a decanter 10;

[0047] (4) The pressure of the decanter 10 is controlled at 0.05-0.8 MPaG, and the temperature is controlled at 40-90°C. The oil phase and the water phase are separated. The water phase containing 1-3 wt% of organic matter is sent to a waste water column 11, and the oil phase containing 3-5 wt% of water is sent to a light component removal column 12;

[0048] (5) The pressure of the waste water column 11 is controlled at 0.05-0.5 MPaG. After separation, the azeotrope of water and isopropylidene acetone obtained at the top of the column is sent back to the decanter 10, and the waste water containing less than 1000 ppm of organic matter obtained at the bottom of the column is sent out of the system;

[0049] (6) The pressure of the light component removal column 12 is controlled at 2-100 kPaA. After separation, the mixture composed of isopropylidene acetone and water (water 6%, isopropylidene acetone 94%) obtained at the top of the column is sent to an isopropylidene acetone refining column 13, and the mixture containing mesitylene, isophorone and heavy oil obtained at the bottom of the column is sent to a mesitylene refining column 14;

[0050] (7) The top pressure of the isopropylidene acetone refining column 13 is controlled at 20-100 kPaG. After separation, the azeotrope of isopropylidene acetone and water obtained at the top of the column is sent back to the decanter 10, and the isopropylidene acetone product with a purity of 99.5 wt% is obtained at the bottom of the column;

[0051] (8) The pressure of the mesitylene refining column 14 is controlled at 2-0.1 MPaG. After separation, the mesitylene product with a purity of 99.5 wt% is obtained at the top of the column, and the mixture composed of isophorone and heavy components (isophorone 91%, the rest being heavy components) obtained at the bottom of the column is sent to an isophorone refining column 15;

[0052] (9) The pressure of the isophorone refining column 15 is controlled at 2 kPa-0.1 MPa G, and after separation, the isophorone product with a purity of 99.9 wt% is obtained at the top, and the heavy components obtained at the bottom are discharged to the outside.

[0053] After the system runs for a period of time, when the single-pass conversion rate of acetone and the selectivity of isophorone and mesityl oxide decrease by 5%-10%, it indicates that the catalyst needs to be regenerated. The specific steps are as follows: first, the reaction system is replaced with nitrogen, after the replacement is completed, the compressed air with a pressure of 0.2-0.3 MPa G is heated to 350-400°C by the regeneration gas heater 4, and then is respectively introduced into the first gas-phase condensation reactor and the second gas-phase condensation reactor at a flow rate of 5-15 m / s, and after 30-50 min, the introduction of compressed air is stopped; then the steam with a pressure of 0.5 MPa G is heated to 350-400°C by the regeneration gas heater 4, and then is respectively introduced into the first gas-phase condensation reactor and the second gas-phase condensation reactor at a flow rate of 1-5 m / s, and after continuous introduction for 3-6 h, the introduction of steam is stopped; the residual water is removed by continuously introducing the compressed air with a pressure of 0.2-0.3 MPa G, which is heated to 350-400°C by the regeneration gas heater 4, and the flow rate is controlled at 5-15 m / s, and after 30-50 min, the introduction of compressed air is stopped; nitrogen is continuously introduced to replace the air in the reaction system until the oxygen content in the analysis system is less than 0.5 vol%, and then the regeneration process is completed.

[0054] Example 1

[0055] When the design scale of isophorone is 10000 t / a and mesityl oxide is produced in parallel, the reaction temperature is 280°C, the annual operating time is 8000 h, the gas-phase condensation reaction pressure is 0.3 MPa G, the single-pass conversion rate of acetone is 35%, the selectivity of isophorone is 62%, the operating pressure of the acetone vaporization column 1 is 0.15 MPa G, the operating pressure of the acetone recovery column 8 is 0.25 MPa G, the operating pressure of the light-removing column 12 is 50 kPa A, the operating pressure of the wastewater column 11 is 0.15 MPa G, the operating pressure of the mesityl oxide refining column 13 is 50 kPa G, the operating pressure of the mesityl oxide refining column 14 is 50 kPa A, and the operating pressure of the isophorone refining column 15 is 50 kPa A. After the system reaction reaches equilibrium, the acetone feed is 45.53 kmol / h (about 2644 kg / h), the isophorone yield is 1250 kg / h, the purity is 99.9%, the mesityl oxide yield is 179 kg / h, the purity is 99.5%, the mesityl oxide is 416 kg / h, the purity is 99.5%, and at the same time, the wastewater is 565 kg / h, the organic matter content in the wastewater is less than 1000 ppm, and the heavy components are 138 kg / h.

[0056] Reaction equation: main reaction: 3 acetone→isophorone+2 water;

[0057] Side reactions: 2 acetone→ mesityl oxide + water, 3 acetone→ TMP + 3 water, N acetone→ CM + Y water (N = 4-8, M = 12-18, Y = 3-6), total conversion of acetone is 97%, single-pass conversion of acetone is 35%.

[0058] Example 2

[0059] According to the design scale of 20000 t / a of isophorone and parallel production of mesityl oxide, the reaction temperature is 240°C, the annual operating time is 8000h, the gas phase condensation reaction pressure is 0.05 MPaG, the single-pass conversion rate of acetone is 25%, the isophorone selectivity is 65%, the operating pressure of the acetone vaporization tower 1 is 0.15 MPaG, the operating pressure of the acetone recovery tower 8 is 0.25 MPaG, the operating pressure of the light component removal tower 12 is 2 kPaA, the operating pressure of the waste water tower 11 is 0.05 MPaG, the operating pressure of the mesityl oxide refining tower 13 is 20 kPaA, the operating pressure of the mesityl oxide refining tower 14 is 2 kPaA, the operating pressure of the isophorone refining tower 15 is 20 kPaA, after the reaction equilibrium of the system, the acetone feed is 88.33 kmol / h (about 5130 kg / h), the isophorone yield is 2500 kg / h, the purity is 99.9%, the mesityl oxide yield is 375 kg / h, the purity is 99.5%, the mesityl oxide yield is 872.3 kg / h, the purity is 99.5%, and at the same time, the waste water produced is 903.89 kg / h, the organic matter content in the waste water is less than 1000 ppm, and the heavy component is 289 kg / h. The total conversion rate of acetone is 96.4%, and the single-pass conversion rate of acetone is 32%.

[0060] Example 3

[0061] According to the isophorone design scale 5000t / a, and parallel production of mesityl oxide, the reaction temperature is 350°C, the annual operating time is 8000h, the gas phase condensation reaction pressure is 0.4MpaG, the one-way conversion rate of acetone is 42%, the isophorone selectivity is 59%, the operating pressure of acetone vaporization tower 1 is 0.5MpaG, the operating pressure of acetone recovery tower 8 is 0.6MpaG, the operating pressure of light component removal tower 12 is 100kPaA, the operating pressure of wastewater tower 11 is 0.5MPaG, the operating pressure of mesityl oxide refining tower 13 is 100kPaG, the operating pressure of mesitylene refining tower 14 is 0.1MPaG, the operating pressure of isophorone refining tower 15 is 100kPaG, after the reaction equilibrium of the system, the acetone feed is 47.21kmol / h (about 2742kg / h), the isophorone yield is 1250kg / h, the purity is 99.9%, the mesityl yield is 86.5kg / h, the purity is 99.5%, the mesityl oxide is 203kg / h, the purity is 99.5%, and at the same time, the wastewater is 203.4kg / h, the organic content in the wastewater is less than 1000ppm, and the heavy component is 83.5kg / h. The total conversion rate of acetone is 97.8%, and the one-way conversion rate of acetone is 42%.

[0062] Example 4

[0063] The design isophorone design scale 5000t / a, without producing mesityl oxide, mesityl oxide returns to the reactor for continuous reaction, the reaction temperature is 300°C, the annual operating time is 8000h, the gas phase condensation reaction pressure is 0.2MpaG, the one-way conversion rate of acetone is 38%, the isophorone selectivity is 85%, the operating pressure of acetone vaporization tower 1 is 0.3MpaG, the operating pressure of acetone recovery tower 8 is 0.4MpaG, the operating pressure of light component removal tower 12 is 50kPaA, the operating pressure of wastewater tower 11 is 0.05MPaG, the operating pressure of mesityl oxide refining tower 13 is 50kPaG, the operating pressure of mesityl refining tower 14 is 50kPaA, the operating pressure of isophorone refining tower 15 is 10kPaA, after the reaction equilibrium of the system, the acetone feed is 16.83kmol / h (about 978kg / h), the isophorone yield is 625kg / h, the mesityl yield is 87kg / h, and at the same time, the wastewater is 203kg / h, and the heavy component is 59kg / h. The total conversion rate of acetone is 96.5%, and the one-way conversion rate of acetone is 38%.

[0064] The above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the essential scope of the present application should also belong to the protection scope of the present application.

Claims

1. A system for producing isophorone and mesityl oxide by a gas phase condensation method, characterized by: The application relates to a production device for preparing isophorone, which comprises an acetone vaporization tower, a first acetone gas-phase condensation reactor, a second acetone gas-phase condensation reactor, an acetone recovery tower, a decanter, a waste water tower, a light component removal tower, an isopropylidene acetone refining tower, a mesitylene refining tower and an isophorone refining tower; the upper portion of the acetone vaporization tower is provided with a liquid-phase acetone inlet; the top gas outlet of the acetone vaporization tower is connected with the top inlet of the first acetone gas-phase condensation reactor through an acetone heat exchanger and an acetone superheater in sequence; the bottom outlet of the first acetone gas-phase condensation reactor is connected with the bottom inlet of the second acetone gas-phase condensation reactor through a cold acetone vaporizer; the top outlet of the second acetone gas-phase condensation reactor is connected with the middle feeding inlet of the acetone recovery tower through the acetone heat exchanger; the top gas outlet of the acetone recovery tower is connected with the gas-phase acetone inlet of the lower portion of the acetone vaporization tower; the bottom discharge outlet of the acetone recovery tower is connected with the decanter through an acetone recovery tower bottom cooler; the water-phase outlet of the decanter is connected with the middle feeding inlet of the waste water tower; the top outlet of the waste water tower is connected with the decanter; the oil-phase outlet of the decanter is connected with the middle feeding inlet of the light component removal tower; the top gas outlet of the light component removal tower is connected with the isopropylidene acetone refining tower; the bottom of the isopropylidene acetone refining tower is provided with an isopropylidene acetone product outlet; the bottom discharge outlet of the light component removal tower is connected with the middle feeding inlet of the mesitylene refining tower; the top of the mesitylene refining tower is provided with a mesitylene product outlet; the bottom discharge outlet of the mesitylene tower is connected with the middle feeding inlet of the isophorone refining tower; and the top of the isophorone refining tower is provided with an isophorone product outlet.

2. The system for producing isophorone and mesityl oxide by a gas phase condensation method according to claim 1, characterized in that: Steam pipes and compressed air pipes are respectively connected to the inlet pipelines of the first acetone gas-phase condensation reactor and the second acetone gas-phase condensation reactor.

3. The system for producing isophorone and mesityl oxide by a gas phase condensation method according to claim 1, characterized in that: The first acetone gas-phase condensation reactor and the second acetone gas-phase condensation reactor are both adiabatic fixed-bed reactors.

4. A process for producing isophorone and mesityl oxide by gas phase condensation using the system according to any one of claims 1 to 3, characterized in that The application further discloses a production method for preparing isophorone. The fresh acetone is sent into an acetone feeding buffer tank, pressurized and then enters the acetone vaporization tower together with the gas-phase acetone from the top of the acetone recovery tower; the pressure of the acetone vaporization tower is controlled to be 0.15-0.5 MPaG; after the acetone is vaporized and the impurity components are removed, the mass concentration of the acetone gas obtained from the top of the acetone vaporization tower is 95%; the acetone gas obtained in the step (1) is heated through an acetone heat exchanger, further heated through an acetone superheater and then enters the first gas-phase condensation reactor for reaction; the temperature of the gas-phase condensation reaction is controlled to be 240-350 DEG C, and the pressure is controlled to be 0.05-0.4 MPaG; after the reaction is completed, the reaction product is sent into the second gas-phase condensation reactor for reaction; the temperature of the gas-phase condensation reaction is controlled to be 240-350 DEG C, and the pressure is controlled to be 0.05-0.4 MPaG; the reaction material is sent into the acetone heat exchanger for heat exchange and cooling and then enters the acetone recovery tower. ​ ​ (3) The pressure of the acetone recovery column is controlled at 0.25-0.6 MPaG, and the acetone in the reaction mixture is separated, and the acetone solution with a mass concentration of 95% obtained at the top of the column is sent back to the acetone vaporization column for recycling, and the water and organic impurities obtained at the bottom of the column are sent to the decanter; (4) The pressure of the decanter is controlled at 0.05-0.8 MPaG, and the temperature is controlled at 40-90℃, and the oil phase and the water phase are separated, and the water phase containing 1-3wt% of organic matter is sent to the waste water column, and the oil phase containing 3-5wt% of water is sent to the light component removal column; (5) The pressure of the waste water column is controlled at 0.05-0.5 MPaG, and after separation, the azeotrope of water and mesityl oxide obtained at the top of the column is sent back to the decanter, and the waste water containing less than 1000 ppm of organic matter obtained at the bottom of the column is sent to the outside; (6) The pressure of the light component removal column is controlled at 2-100 kPaA, and after separation, the mixture composed of mesityl oxide and water obtained at the top of the column is sent to the mesityl oxide refining column, and the mixture containing mesityl oxide, isophorone and heavy oil obtained at the bottom of the column is sent to the mesityl oxide refining column; (7) The pressure at the top of the mesityl oxide refining column is controlled at 20 kPaA-100 kPaG, and after separation, the azeotrope of mesityl oxide and water obtained at the top of the column is returned to the decanter, and the mesityl oxide product with a purity of 99.5wt% is obtained at the bottom of the column; (8) The pressure of the mesityl oxide refining column is controlled at 2 kPaA-0.1 MPaG, and after separation, the mesityl oxide product with a purity of 99.5wt% is obtained at the top of the column, and the mixture composed of isophorone and heavy components obtained at the bottom of the column is sent to the isophorone refining column; (9) The pressure of the isophorone refining column is controlled at 2 kPaA-0.1 MPaG, and after separation, the isophorone product with a purity of 99.9wt% is obtained at the top of the column, and the heavy components obtained at the bottom of the column are discharged to the outside.

5. The process for producing isophorone and mesityl oxide by a gas phase condensation method according to claim 4, characterized by The specific steps of the catalyst regeneration operation are as follows: first, the reaction system is replaced with nitrogen, and after the replacement is completed, the compressed air with a pressure of 0.2-0.3 MPaG is heated to 350-400℃ by the regeneration gas heater, and then is introduced into the first and second gas phase condensation reactors at a flow rate of 5-15 m / s, and the introduction of compressed air is stopped after 30-50 min; then the steam with a pressure of 0.5 MPaG is heated to 350-400℃ by the regeneration gas heater, and then is introduced into the first and second gas phase condensation reactors at a flow rate of 1-5 m / s, and the introduction of steam is stopped after 3-6 h of continuous introduction; the residual water is removed by continuously introducing compressed air with a pressure of 0.2-0.3 MPaG, which is heated to 350-400℃ by the regeneration gas heater, and the flow rate is controlled at 5-15 m / s, and the introduction of compressed air is stopped after 30-50 min; nitrogen is continuously introduced to replace the air in the reaction system until the oxygen content in the analysis system is less than 0.5vt%, and the regeneration process is completed.

Images