Production system and production method of diacetone alcohol

Abstract

The invention discloses a diacetone alcohol production system which is characterized in that an outlet of a raw material tank is communicated with a feed port at the bottom of a fixed bed reactor through a raw material conveying pipeline, a discharge port at the top of the fixed bed reactor is communicated with a gas-liquid separation tank, and a liquid phase outlet of the gas-liquid separation tank is communicated with a feed port of a falling film evaporator; a gas-phase outlet of the gas-liquid separation tank flows back to the raw material tank through a first backflow pipeline, a gas-phase outlet of the falling-film evaporator flows back to the raw material tank through a second backflow pipeline, an outlet of the falling-film evaporator is connected with an inlet of the dividing wall rectifying tower through a pipeline, and the upper portion of the dividing wall rectifying tower is divided into a left area and a right area by a center partition plate. An inlet of the dividing wall rectifying tower is positioned in the middle of the acetone area; and a gas-phase discharge hole is formed in the side wall close to the lower part of the dividing wall rectifying tower. According to the method, most AC is recycled by adopting simple evaporation equipment, and the method has the characteristics of simple process, remarkable separation effect and lower energy consumption.

Description

Technical Field

[0001] The invention relates to the technical field of chemical reactions and separations, and in particular to a production system and a production method of diacetone alcohol. Background Art

[0002] DAA is an important downstream product of acetone (AC), commonly used as a solvent, metal cleaning agent, wood and drug preservative, antifreeze agent and electroplating additive, etc., and is also used in organic synthesis and electrophoresis analysis. DAA is mainly produced by condensation of acetone in the presence of an alkaline catalyst. The reaction is a reversible exothermic process with a low equilibrium constant. It needs to be carried out at a lower temperature to improve the reaction conversion rate. The commonly used reaction temperature is between 5 and 20°C. Literature reports that the maximum conversion rate of AC is about 20% when reacting at 5°C.

[0003] The production process of DAA requires a large amount of unreacted AC to be distilled off due to the low conversion rate. Patent CN201822163443.9 discloses a diacetone alcohol production system based on a resin exchange column, and a common distillation tower is used to separate AC and DAA. Patent CN201510452592.5 reports a method for continuous production of diacetone alcohol, which uses a multi-stage series distillation process to separate AC and DAA. These methods all use conventional distillation technology combined with a reaction process, and the energy consumption is generally high.

[0004] Secondly, since DAA is less stable at high temperatures and is easy to decompose, the distillation process needs to be carried out under reduced pressure to improve the yield of DAA, but this will inevitably lead to difficulties in acetone recovery. Vacuum distillation requires considerable refrigeration consumption. How to optimize the process and design a new process with reasonable energy consumption and high product yield is the key to reducing the production cost of DAA. Summary of the invention

[0005] The object of the present invention is to provide a production system of diacetone alcohol.

[0006] The invention also discloses a production method of a diacetone alcohol production system.

[0007] The innovation of the present invention is that the present invention uses a simple evaporation device to recover most of the AC, which has the characteristics of simple process, significant separation effect and low energy consumption.

[0008] To achieve the above-mentioned object of the invention, the technical scheme of the present invention is: a production system of diacetone alcohol, characterized in that it comprises a raw material tank, a fixed bed reactor, a rising film evaporator, a gas-liquid separation tank, a falling film evaporator, and a distillation tower, wherein the outlet of the raw material tank is connected to the feed port at the bottom of the fixed bed reactor through a raw material conveying pipeline, the discharge port at the top of the fixed bed reactor is connected to the gas-liquid separation tank, the liquid phase outlet of the gas-liquid separation tank is connected to the feed port of the falling film evaporator, the gas phase outlet of the gas-liquid separation tank is refluxed to the raw material tank through a No. 1 reflux pipeline, the gas phase outlet of the falling film evaporator is refluxed to the raw material tank through a No. 2 reflux pipeline, and the falling film The outlet of the evaporator is connected to the inlet of the distillation tower next door through a pipeline. The upper part of the distillation tower next door is divided into two zones by a central partition, one zone is an acetone zone and the other zone is an isopropyl oxide zone. The inlet of the distillation tower next door is located in the middle of the acetone zone. A diacetone alcohol gas phase discharge port is provided near the lower side wall of the distillation tower next door; a No. 3 reflux pipeline for partially refluxing the material at the top of the acetone zone is provided at the top of the acetone zone, and an acetone condenser is provided on the No. 3 reflux pipeline; a No. 4 reflux pipeline for partially refluxing the material at the top of the isopropyl oxide zone is provided at the top of the isopropyl oxide zone, and a mesityl oxide condenser is provided on the No. 4 reflux pipeline.

[0009] Furthermore, a No. 5 reflux pipe is provided at the discharge port at the bottom of the distillation tower next door, and refluxes to the reflux port near the bottom of the distillation tower next door, and a tower bottom reboiler is provided on the No. 5 reflux pipe.

[0010] Furthermore, a phase separation tank and an oil phase storage tank are provided on the No. 4 reflux pipeline, the oil phase outlet of the phase separation tank is connected to the oil phase storage tank, and a mesityl oxide discharge pipe is provided on the No. 4 reflux pipeline.

[0011] Furthermore, a No. 6 reflux pipe for reflux to the raw material tank is provided at the rear end of the acetone condenser on the No. 3 reflux pipe.

[0012] Furthermore, a cooler is provided on the track.

[0013] Furthermore, the reflux pipeline is joined with the No. 2 reflux pipeline, and a distillation condenser is provided at the joining point.

[0014] Furthermore, a liquid overflow structure is provided near the bottom of the mesityl oxide zone, and gas-phase communicating pipes are provided above and below the liquid-phase overflow device to connect to the outside of the distillation tower next door, and a flow regulating valve is installed on the gas-phase communicating pipes.

[0015] A production method of a diacetone alcohol production system comprises the following steps:

[0016] (1) Acetone in the raw material tank is transported to a fixed bed reactor for condensation reaction to generate diacetone alcohol and mesityl oxide as a by-product;

[0017] (2) The material of the fixed bed reactor flows out from the top and enters the rising film evaporator, the gas-liquid separator and the falling film evaporator in sequence. The gas phase of the gas-liquid separator and the falling film evaporator is completely condensed into liquid and then sent to the raw material tank. The material of the fixed bed reactor includes diacetone alcohol generated by the condensation reaction and the by-product mesityl oxide and unreacted acetone;

[0018] (3) The liquid phase discharged from the falling film evaporator is sent to the distillation tower next door, and the temperature is controlled so that the acetone in the liquid phase entering is vaporized, while mesityl oxide and diacetone are not vaporized. The gas phase in the acetone zone rises continuously, and the top gas phase is condensed and partly returns to the acetone zone at the top of the tower as reflux, and the other part is sent to the raw material tank; the liquid phase flows downward along the central partition through the packing layer of the distillation tower next door, and the acetone content gradually decreases. When the material reaches the bottom of the central partition, it is basically free of acetone, and can be separated from the liquid phase in the mesityl oxide zone of the central partition. The gas phase rising from the lower part of the distillation tower next door is divided into two streams at the bottom of the central partition, one stream directly enters the acetone zone and the other stream enters the mesityl oxide zone; the gas phase in the mesityl oxide zone is partially returned to the mesityl oxide zone as reflux after condensation, and the other stream is used as the mesityl oxide product at the top of the tower; in the middle and lower part of the distillation tower next door, the content of the mesityl oxide zone in the material decreases as it goes down the tower, and when it reaches the diacetone alcohol gas phase discharge port, the product is condensed to obtain diacetone alcohol.

[0019] Furthermore, after condensation, the gas phase in the mesityl oxide zone enters a phase separation tank to separate a water phase, and the separated oil phase is sent to an oil phase storage tank, and then part of it is returned to the mesityl oxide zone as reflux, and the other part is used as a mesityl oxide product at the top of the tower. The materials in the bottom of the distillation tower next door are mostly vaporized by the reboiler at the bottom of the tower and returned to the distillation tower next door, and the remaining bottom liquid is discharged from the tower irregularly.

[0020] Furthermore, the acetone in the raw material tank is first cooled and then enters the fixed bed reactor.

[0021] The beneficial effects of the present invention are:

[0022] 1. The present invention adopts a simple evaporation device to recover most of the AC, which has the characteristics of simple process, significant separation effect and low energy consumption.

[0023] 2. The dividing wall distillation tower used in the present invention has the advantages of advanced technology, high separation efficiency, short material residence time and high product yield.

[0024] 3. The present invention adopts a gas phase flow control strategy in the tower, which is also conducive to adjusting the distribution ratio of the gas phase on both sides of the central partition at any time according to the content of the by-product mesityl oxide, and is more convenient for operation control.

[0025] 4. The present invention adopts rising film and falling film evaporators as simple distillation equipment, which also has the characteristics of high heat transfer efficiency, short material residence time and easy operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of the present invention. DETAILED DESCRIPTION

[0027] The technical scheme in the embodiment of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Embodiment 1: A production system of diacetone alcohol, comprising a raw material tank 1, a fixed bed reactor 2, a rising film evaporator 3, a gas-liquid separation tank 4, a falling film evaporator 5, and a distillation tower 6. The outlet of the raw material tank 1 is connected to the feed port at the bottom of the fixed bed reactor 2 through a raw material delivery pipeline 7, a cooler 20 is provided on the raw material delivery pipeline 7, the discharge port at the top of the fixed bed reactor 2 is connected to the gas-liquid separation tank 4, the liquid phase outlet of the gas-liquid separation tank 4 is connected to the feed port of the falling film evaporator 5, the gas phase outlet of the gas-liquid separation tank 4 is refluxed to the raw material tank 1 through a No. 1 reflux pipeline 8, the gas phase outlet of the falling film evaporator 5 is refluxed to the raw material tank 1 through a No. 2 reflux pipeline 9, the No. 1 reflux pipeline 8 and the No. 2 reflux pipeline 9 are merged, and a distillation condenser 21 is provided at the merged point. The outlet of the falling film evaporator 5 is connected to the inlet of the distillation tower 6 next door through a pipeline. The upper part of the distillation tower 6 next door is divided into two left and right zones by a central partition 6.4, one zone is an acetone zone 6.1, and the other zone is an isopropylamine oxide zone 6.2. The inlet of the distillation tower 6 next door is located in the middle of the acetone zone 6.1. A diacetone alcohol gas phase discharge port 6.3 is provided near the lower side wall of the distillation tower 6 next door; a liquid phase overflow structure 6.5 is provided near the bottom of the isopropylamine oxide zone 6.2. A gas phase communicating pipe 6.6 is opened above and below the liquid phase overflow device 6.5 to connect to the outside of the distillation tower 6 next door, and a flow regulating valve 6.7 is installed on the gas phase communicating pipe 6.6. A No. 3 reflux pipeline 10 for partially refluxing the material at the top of the acetone zone 6.1 is provided at the top of the acetone zone 6.1, an acetone condenser 11 is provided on the No. 3 reflux pipeline 10, and a No. 6 reflux pipeline 19 for refluxing to the raw material tank 1 is provided at the rear end of the acetone condenser 11 on the No. 3 reflux pipeline 10. A No. 4 reflux pipeline 12 for partially refluxing the material at the top of the mesityl oxide zone 6.2 is provided at the top of the mesityl oxide zone 6.2, and a mesityl oxide condenser 13 is provided on the No. 4 reflux pipeline 12. A phase separation tank 16 and an oil phase storage tank 17 are provided on the No. 4 reflux pipeline 12, the oil phase outlet of the phase separation tank 16 is connected to the oil phase storage tank 17, and a mesityl oxide discharge pipe 18 is provided on the No. 4 reflux pipeline 12. A No. 5 reflux pipe 14 is provided at the discharge port at the bottom of the distillation tower 6 next to the wall to reflux to the reflux port near the bottom of the distillation tower 6 next to the wall, and a bottom reboiler 15 is provided on the No. 5 reflux pipe 14. Embodiment 2: A production method of a diacetone alcohol production system, comprising the following steps:

[0028] (1) Acetone in the raw material tank 1 is transported to the fixed bed reactor 2 for condensation reaction to generate diacetone alcohol and by-product mesityl oxide. The acetone in the raw material tank 1 is first cooled and then enters the fixed bed reactor 2;

[0029] (2) The material of the fixed bed reactor 2 flows out from the top and enters the rising film evaporator 3, the gas-liquid separator 4 and the falling film evaporator 5 in sequence. The gas phases of the gas-liquid separator 4 and the falling film evaporator 5 are all condensed into liquid and then sent to the raw material tank 1. The material of the fixed bed reactor 2 includes diacetone alcohol generated by the condensation reaction and the by-product mesityl oxide and unreacted acetone;

[0030] (3) The liquid phase discharged from the falling film evaporator 5 is sent to the distillation tower 6 next to the wall, and the temperature is controlled so that the acetone in the liquid phase entering is vaporized, while mesityl oxide and diacetone are not vaporized. The gas phase in the acetone zone rises continuously, and the top gas phase is condensed and partly returns to the acetone zone at the top of the tower as reflux, and the other part is sent to the raw material tank; the liquid phase flows downward along the central partition 6.4 through the packing layer of the distillation tower 6 next to the wall, and the acetone content gradually decreases. When the material reaches the bottom of the central partition 6.4, there is basically no acetone, and it can merge with the liquid phase in the mesityl oxide zone of the central partition 6.4 and enter the middle and lower part of the distillation tower 6 next to the wall. The gas phase rising from the lower part of the distillation tower 6 next to the wall is divided into two streams at the bottom of the central partition 6.4, one stream directly enters the acetone zone 6.1, and the other stream enters the mesityl oxide zone 6.2; the gas phase of the mesityl oxide zone 6.2 is partially returned to the mesityl oxide zone 6.2 as reflux after condensation, and the other part is used as the mesityl oxide product at the top of the tower; the gas phase of the mesityl oxide zone 6.2 is condensed, enters the phase separation tank 16 to separate the water phase, and the separated oil phase is sent to the oil phase storage tank 17, and then partially returned to the mesityl oxide zone 6.2 as reflux, and the other part is used as the mesityl oxide product at the top of the tower. In the middle and lower part of the distillation tower 6 next door, the content of the mesityl oxide zone in the material decreases as the tower goes down, and when the product reaches the diacetone alcohol gas phase discharge port 6.3, diacetone alcohol is condensed, and the material in the bottom of the distillation tower 6 next door is mostly vaporized by the bottom reboiler and returned to the distillation tower next door 6, and the remaining kettle liquid is discharged from the tower irregularly.

[0031] Example 3: The fixed bed reactor 2 has a diameter of φ600 mm, a bed catalyst loading height of 6.0 m, and contains 1.7 m of compressed columnar catalyst. 3 The number of theoretical plates of the packing on the left and right sides of the center partition 6.4 of the distillation tower 6 is 14, and the number of theoretical plates at the bottom of the center partition 6.4 is 16.

[0032] The operating conditions are as follows: the flow rate of acetone raw material is 2.0m 3 / h (containing 0.5% water), the reaction temperature is 12°C; the rising film evaporator 3 is controlled at 62°C, and the falling film evaporator 5 is controlled at 70°C; the top pressure of the central partition 6.4 acetone zone 6.1 is -0.085MPa, the top reflux ratio of the acetone zone 6.1 is 2:1, the top pressure of the isopropyl alcohol zone 6.2 is -0.09MPa, and the top reflux ratio of the isopropyl alcohol zone 6.2 is 15:1.

[0033] According to the mathematical simulation calculation of kinetics, chemical equilibrium and phase equilibrium models, the stable reaction results are obtained: the acetone conversion rate is 14.6%, and the outlet material composition of the fixed bed reactor 2 is as follows: flow rate 1560kg / h, AC content 84.9%, DAA 14.1%, MO 0.4%, water 0.6%. After two-stage evaporation, the outlet liquid material composition of the falling film evaporator 5 is: flow rate 404kg / h, AC content 45.7%, DAA 51.0%, MO 1.5%, water 1.8%.

[0034] The simulation results of the distillation tower are as follows: the top temperature of the acetone zone 6.1 is 9.5°C, the AC product volume is 185.5kg / h, the AC content is 99.5%, and the water content is 0.5%; the top temperature of mesityl oxide 6.2 is 32.1°C, the oil phase MO product volume is 6.1kg / h, and the water phase product volume is 6.4kg / h; the temperature of the diacetone alcohol gas phase outlet 6.3 is 114.6°C, the DAA product volume is 206kg / h, and the content is 99.95%.

[0035] Example 4: The fixed bed reactor 2 has a diameter of φ600 mm, a bed catalyst loading height of 6.0 m, and contains 1.7 m of compressed columnar catalyst. 3 The number of theoretical plates of the packing on the left and right sides of the center partition 6.4 of the distillation tower 6 is 14, and the number of theoretical plates at the bottom of the center partition is 16.

[0036] The operating conditions are as follows: the flow rate of acetone raw material is 2.0m3 / h (containing 0.5% water), the reaction temperature is 18°C; the rising film evaporator 3 is controlled at 65°C, and the falling film evaporator 5 is controlled at 72°C; the top pressure of the central baffle acetone zone 6.1 is -0.09MPa, the top reflux ratio of the acetone zone 6.1 is 2:1, the top pressure of the mesityl oxide zone 6.2 is -0.095MPa, and the top reflux ratio of the mesityl oxide zone 6.2 is 15:1. According to the mathematical simulation calculation of the kinetics, chemical equilibrium and phase equilibrium model, the stable reaction result is obtained: the acetone conversion rate is 13.7%, and the outlet material composition of the fixed bed reactor 2 is as follows: the flow rate is 1560kg / h, the AC content is 85.9%, DAA is 13.1%, MO is 0.4%, and water is 0.6%. After two-stage evaporation, the composition of the liquid material at the outlet of the falling film evaporator 5 is: flow rate 324 kg / h, AC content 41.2%, DAA 55.4%, MO 1.7%, water 1.7%.

[0037] The simulation results of the distillation tower are as follows: the top temperature of the acetone zone 6.1 is 1.3°C, the AC product volume is 134.2 kg / h, the AC content is 99.5%, and the water content is 0.5%; the top temperature of the mesityl oxide zone 6.2 is 19.6°C, the oil phase MO product volume is 5.4 kg / h, and the water phase product volume is 4.8 kg / h; the temperature of the diacetone alcohol gas phase outlet 6.3 is 109.2°C, the DAA product volume is 179.6 kg / h, and the content is 99.95%. Example 5: The fixed bed reactor 2 has a tower diameter of φ600 mm, a bed catalyst filling height of 6.0 m, and a compressed columnar catalyst of 1.7 m 3 The number of theoretical plates of the packing on the left and right sides of the center partition 6.4 of the distillation tower 6 is 10, and the number of theoretical plates at the bottom of the center partition 6.4 is 12.

[0038] The operating conditions are as follows: the flow rate of acetone raw material is 2.0m3 / h (containing 0.5% water), the reaction temperature is 12°C; the rising film evaporator is controlled at 62°C, and the falling film evaporator is controlled at 70°C; the top pressure of the central baffle acetone zone 6.1 is -0.09MPa, the top reflux ratio of the acetone zone 6.1 is 1:1, the top pressure of the mesityl oxide zone 6.2 is -0.095MPa, and the top reflux ratio of the mesityl oxide zone 6.2 is 15:1. According to the mathematical simulation calculation of the kinetics, chemical equilibrium and phase equilibrium model, the stable reaction result is obtained: the acetone conversion rate is 14.6%, and the outlet material composition of the fixed bed reactor 2 is as follows: the flow rate is 1560kg / h, the AC content is 84.9%, the DAA is 14.1%, the MO is 0.4%, and the water is 0.6%. After two-stage evaporation, the composition of the liquid material at the outlet of the falling film evaporator 5 is: flow rate 404 kg / h, AC content 45.7%, DAA 51.0%, MO 1.5%, water 1.8%.

[0039] The simulation results of the distillation tower are as follows: the top temperature of the acetone zone 6.1 is 1.5°C, the AC product volume is 186.2 kg / h, the AC content is 99.1%, and the water content is 0.9%; the top temperature of the mesityl oxide zone 6.2 is 19.6°C, the oil phase MO product volume is 6.1 kg / h, and the water phase product volume is 5.6 kg / h; the temperature of the diacetone alcohol gas phase outlet 6.3 is 105.2°C, the DAA product volume is 206.1 kg / h, and the content is 99.9%. Example 6: The fixed bed reactor 2 has a tower diameter of φ600 mm, a bed catalyst loading height of 6.0 m, and a compressed columnar catalyst of 1.7 m 3 The number of theoretical plates of the packing on the left and right sides of the center partition 6.4 of the distillation tower 6 is 10, and the number of theoretical plates at the bottom of the center partition is 12.

[0040] The operating conditions are as follows: the flow rate of acetone raw material is 2.0m3 / h (containing 0.5% water), the reaction temperature is 18°C; the rising film evaporator 3 is controlled at 65°C, and the falling film evaporator 5 is controlled at 72°C; the top pressure of the central baffle acetone zone 6.1 is -0.09MPa, the top reflux ratio of the acetone zone 6.1 is 1:1, the top pressure of the mesityl oxide zone 6.2 is -0.095MPa, and the top reflux ratio of the mesityl oxide zone 6.2 is 15:1. According to the mathematical simulation calculation of the kinetics, chemical equilibrium and phase equilibrium model, the stable reaction result is obtained: the acetone conversion rate is 13.7%, and the outlet material composition of the fixed bed reactor 2 is as follows: the flow rate is 1560kg / h, the AC content is 85.9%, the DAA is 13.1%, the MO is 0.4%, and the water is 0.6%. After two-stage evaporation, the composition of the liquid material at the outlet of the falling film evaporator 5 is: flow rate 324 kg / h, AC content 41.2%, DAA 55.4%, MO 1.7%, water 1.7%.

[0041] The simulation calculation results of the distillation tower 6 are as follows: the top temperature of the acetone zone 6.1 is 1.6°C, the AC product volume is 134.9 kg / h, the AC content is 99.0%, and the water content is 1.0%; the top temperature of the isopropyl alcohol zone 6.2 is 19.6°C, the oil phase MO product volume is 5.4 kg / h, and the water phase product volume is 4.1 kg / h; the temperature of the diacetone alcohol gas phase outlet 6.3 is 105.4°C, the DAA product volume is 179.6 kg / h, and the content is 99.92%.

[0042] The described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A production system of diacetone alcohol, characterized in that: The invention comprises a raw material tank, a fixed bed reactor, a rising film evaporator, a gas-liquid separation tank, a falling film evaporator and a distillation tower next door. The outlet of the raw material tank is connected with the feed port at the bottom of the fixed bed reactor through a raw material delivery pipeline. The discharge port at the top of the fixed bed reactor is connected with the gas-liquid separation tank. The liquid phase outlet of the gas-liquid separation tank is connected with the feed port of the falling film evaporator. The gas phase outlet of the gas-liquid separation tank is refluxed to the raw material tank through a No. 1 reflux pipeline. The gas phase outlet of the falling film evaporator is refluxed to the raw material tank through a No. 2 reflux pipeline. The outlet of the falling film evaporator is connected with the inlet of the distillation tower next door through a pipeline. The upper part of the distillation tower next door is divided into two left and right zones by a central partition, one zone is an acetone zone and the other zone is an isopropyl oxide zone, the inlet of the distillation tower next door is located in the middle of the acetone zone, and a diacetone alcohol gas phase discharge port is provided near the lower side wall of the distillation tower next door; a No. 3 reflux pipeline for partially refluxing the material at the top of the acetone zone is provided at the top of the acetone zone, and an acetone condenser is provided on the No. 3 reflux pipeline; a No. 4 reflux pipeline for partially refluxing the material at the top of the isopropyl oxide zone is provided at the top of the isopropyl oxide zone, and a mesityl oxide condenser is provided on the No. 4 reflux pipeline.

2. The production system of diacetone alcohol according to claim 1, characterized in that: A No. 5 reflux pipe is arranged at the discharge port at the bottom of the distillation tower next door, and the liquid flows back to the reflux port near the bottom of the distillation tower next door. A tower bottom reboiler is arranged on the No. 5 reflux pipe.

3. The production system of diacetone alcohol according to claim 1, characterized in that: The No. 4 reflux pipeline is provided with a phase separation tank and an oil phase storage tank, the oil phase outlet of the phase separation tank is communicated with the oil phase storage tank, and the No. 4 reflux pipeline is provided with a mesityl oxide discharge pipe.

4. The production system of diacetone alcohol according to claim 1, characterized in that: A No. 6 reflux pipeline for reflux to the raw material tank is arranged at the rear end of the acetone condenser on the No. 3 reflux pipeline.

5. The production system of diacetone alcohol according to claim 1, characterized in that: A cooler is provided on the raw material conveying pipeline.

6. The production system of diacetone alcohol according to claim 1, characterized in that: The No. 1 reflux pipeline and the No. 2 reflux pipeline are joined, and a distillation condenser is arranged at the joining point.

7. The production system of diacetone alcohol according to claim 1, characterized in that: A liquid phase overflow structure is provided near the bottom of the mesityl oxide zone, and gas-phase communicating pipes are provided above and below the liquid phase overflow device to connect with the outside of the distillation tower next door, and a flow regulating valve is installed on the gas-phase communicating pipes.

8. A method for producing diacetone alcohol according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Acetone in the raw material tank is transported to a fixed bed reactor for condensation reaction to generate diacetone alcohol and mesityl oxide as a by-product; (2) The material of the fixed bed reactor flows out from the top and enters the rising film evaporator, the gas-liquid separator and the falling film evaporator in sequence. The gas phase of the gas-liquid separator and the falling film evaporator is completely condensed into liquid and then sent to the raw material tank. The material of the fixed bed reactor includes diacetone alcohol generated by the condensation reaction and the by-product mesityl oxide and unreacted acetone; (3) The liquid phase discharged from the falling film evaporator is sent to the distillation tower next door, and the temperature is controlled so that the acetone in the liquid phase entering is vaporized, while mesityl oxide and diacetone are not vaporized. The gas phase in the acetone zone rises continuously, and the top gas phase is condensed and partly returns to the acetone zone at the top of the tower as reflux, and the other part is sent to the raw material tank; the liquid phase flows downward along the central partition through the packing layer of the distillation tower next door, and the acetone content gradually decreases. When the material reaches the bottom of the central partition, it is basically free of acetone, and can be separated from the liquid phase in the mesityl oxide zone of the central partition. The gas phase rising from the lower part of the distillation tower next door is divided into two streams at the bottom of the central partition, one stream directly enters the acetone zone and the other stream enters the mesityl oxide zone; the gas phase in the mesityl oxide zone is partially returned to the mesityl oxide zone as reflux after condensation, and the other stream is used as the mesityl oxide product at the top of the tower; in the middle and lower part of the distillation tower next door, the content of the mesityl oxide zone in the material decreases as it goes down the tower, and when it reaches the diacetone alcohol gas phase discharge port, the product is condensed to obtain diacetone alcohol.

9. The production method of the diacetone alcohol production system according to claim 8, characterized in that: The gas phase in the mesityl oxide zone is condensed and enters a phase separation tank to separate the water phase. The separated oil phase is sent to an oil phase storage tank, and then part of it is returned to the mesityl oxide zone as reflux and the other part is used as the mesityl oxide product at the top of the tower.

10. The production method of diacetone alcohol according to claim 8, characterized in that: The materials in the bottom of the distillation tower next door are mostly vaporized by the bottom reboiler and returned to the distillation tower next door, and the remaining bottom liquid is discharged from the tower irregularly. The acetone in the raw material tank is first cooled and then enters the fixed bed reactor.

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