CN217221411U - System for producing epoxypropane by reactive distillation - Google Patents

Abstract

The utility model discloses a system for reaction rectification production epoxypropane has solved the high problem of energy consumption height, equipment investment and running cost that current system exists. The technical scheme includes that the reaction rectifying tower is included, there is gaseous phase propylene export at reaction rectifying tower top, and there is liquid phase product export bottom, and the lateral wall has feed inlet and propylene circulation import, and the upper segment of reaction rectifying tower is equipped with and is located the packing layer of feed inlet top, the middle section are equipped with the catalyst bed that is located the feed inlet below, gaseous phase propylene export in proper order through condenser, knockout drum with propylene circulation access connection. The method has the advantages of extremely simple process, low equipment investment and operation cost, high propylene oxide yield and propylene recovery rate, full utilization of reaction heat and great reduction of energy consumption.

Description

System for producing epoxypropane by reactive distillation

Technical Field

The utility model relates to a propylene oxide production field, specific system for reaction rectification production propylene oxide that says so.

Background

The process technology for producing the propylene oxide by reacting the hydrogen peroxide with the propylene in the presence of the methanol as a solvent, which is called HPPO method for short, has the characteristics of few byproducts, low comprehensive energy consumption and the like, and is one of mainstream and advanced propylene oxide production technologies at present. At present, the process technology is foreign technology, and corresponding production devices are introduced and built domestically and stably operate.

The prior HPPO process adopts a tubular reactor, reaction materials are fed into the tube, and a molecular sieve catalyst with small particle size is filled in the tube. The exothermic quantity is great in the reaction process, the heat exchange between reactants and the temperature-regulated water is realized by introducing the temperature-regulated water outside the reaction pipe, the reaction heat is taken away by the circulating temperature-regulated water, and then the temperature of the temperature-regulated water is reduced by the heat exchange between the circulating water and the temperature-regulated water. The reaction heat in the whole process can not be utilized and must be completely taken away by circulating water, evaporated water or chilled water. The reaction product needs to be separated due to the large excess of propylene in the reaction product. The whole process has higher energy consumption, more equipment and large investment and occupied area.

Disclosure of Invention

The utility model aims at solving the technical problem and providing a process for producing epoxypropane by reaction rectification, which has the advantages of simple process, low equipment investment and operation cost, high epoxypropane yield and propylene recovery rate, full utilization of reaction heat and great reduction of energy consumption.

The technical scheme includes that the reaction rectifying tower is included, there is gaseous phase propylene export at reaction rectifying tower top, and there is liquid phase product export bottom, and the lateral wall has feed inlet and propylene circulation import, and the upper segment of reaction rectifying tower is equipped with and is located the packing layer of feed inlet top, middle section are equipped with the catalyst bed that is located the feed inlet below, gaseous phase propylene export in proper order through condenser, knockout drum with propylene circulation access connection.

The catalyst bed has a multi-layer structure.

Gas phase communicating pipes are connected between the beds.

The catalyst bed layer is of a three-layer structure.

And a feeding spray pipe connected with the feeding hole is arranged above the catalyst bed layer.

The propylene circulating inlet comprises a first propylene circulating inlet arranged above the packing layer and a second propylene circulating inlet arranged at the catalyst bed layer.

And a circulating spray pipe connected with the first propylene circulating inlet is arranged above the packing layer.

The gas phase outlet of the condenser and the liquid separation tank are connected with the inlet of the deep cooler, and the liquid phase outlet of the deep cooler is connected with the liquid separation tank.

The system also comprises a regeneration system, wherein the regeneration system comprises a shell side or a tube side of a regeneration heat exchanger and a circulating regeneration heater which are connected, and the circulating regeneration heater is connected with a second propylene circulating inlet on the side wall of the reactive distillation tower.

And a liquid-phase product outlet at the bottom of the reactive distillation tower is also connected with the tube side or the shell side of the regenerative heat exchanger through a circulating pump.

The excessive propylene absorbs heat to react and is gasified and discharged from the top by controlling the pressure in the tower to be 1.8-2.3MPaG, so that the gasification and separation of the propylene are realized, the purity of the gas phase propylene which is gasified and separated is high, the gas phase propylene is condensed and liquefied by a condenser and separated by a liquid separating tank and then returns to the tower, the purpose of controlling the reaction temperature in the tower is realized, the recovery rate of the propylene is greatly improved, a refrigeration compressor and a large amount of energy consumption are not needed, only the condenser and the liquid separating tank are needed, the energy consumption is saved, and the equipment investment and the operation cost are reduced; the upper section packing layer of the reaction rectifying tower is used for rectifying propylene, the middle section is provided with a catalyst bed layer to ensure that the reaction is carried out under the catalyst, and the middle section is provided with the catalyst bed layer positioned below the feed port by arranging a multilayer structure to be matched with the gradient control of the concentration and the temperature of the propylene; the gas-phase communicating pipe is arranged between the beds, so that the unbalanced phenomenon of gas-liquid phase load of the beds can be effectively adjusted, and flooding is avoided.

The system is simple, the reaction temperature is low, the safety and stability are good, the propylene recovery rate is high, the epoxy propylene yield is high, the equipment investment and the operation cost are low, the occupied area is small, the overall energy consumption is only about 30 percent of that of the foreign HPPO technology, and the technical effect is extremely obvious.

Drawings

Fig. 1 is a schematic view of the system of the present invention.

Wherein, 1-a filler layer; 2-a collection redistributor; 3-catalyst bed layer; 4-gas phase communicating pipe; 6-circulating regenerative heater; 7-a regenerative heat exchanger; 8-a circulating pump; 9-a condenser; 10-deep cooling; 11-liquid separation tank; 12-a reflux pump; 13-reaction rectifying tower, 13.1-gas phase propylene outlet, 13.2-liquid phase product outlet, 13.3-feed inlet, 13.4-first propylene circulating inlet, 13.5-second propylene circulating inlet, 14-feeding spray pipe and 15-circulating spray pipe.

Detailed Description

The invention will be further explained with reference to the drawings:

referring to fig. 1, the top of the reactive distillation column 13 is provided with a gas phase propylene outlet 13.1, the bottom of the reactive distillation column is provided with a liquid phase product outlet 13.2, the side wall of the reactive distillation column is provided with a feed inlet 13.3 and a propylene circulation inlet, the upper section of the reactive distillation column is provided with a packing layer 1 positioned above the feed inlet 13.3, the middle section of the reactive distillation column is provided with a catalyst bed layer 3 positioned below the feed inlet 13.3, and the propylene circulation inlet comprises a first propylene circulation inlet 13.4 arranged above the packing layer 1 and a second propylene circulation inlet 13.5 arranged at the catalyst bed layer 3. The gas phase propylene outlet 13.1 is sequentially connected with the first propylene circulation inlet 13.4 and the second propylene circulation inlet 13.5 through a condenser 9, a liquid separating tank 11 and a reflux pump 12. The gas phase outlets of the condenser 9 and the liquid separating tank 11 are connected with the inlet of the deep cooler 10, and the liquid phase outlet of the deep cooler 10 is connected with the liquid separating tank 11.

And a circulating spray pipe 15 connected with the first propylene circulating inlet 13.4 is arranged above the packing layer 1. And a feeding spray pipe 14 connected with the feeding hole 13.3 is arranged above the catalyst bed layer 3.

The catalyst bed layers 3 are of a multi-layer structure, preferably a three-layer structure, gas-phase communicating pipes 4 are connected among the bed layers, and a collecting redistributor 2 is arranged above each bed layer.

The device is characterized by further comprising a regeneration system, wherein the regeneration system comprises a shell side or a tube side of the regeneration heat exchanger 7 and a circulating regeneration heater 6 which are connected, the circulating regeneration heater 6 is connected with a second propylene circulating inlet 13.5 on the side wall of the reactive distillation tower 13, and a liquid-phase product outlet at the bottom of the reactive distillation tower 13 is also connected with the tube side or the shell side of the regeneration heat exchanger 7 through a circulating pump 8.

The process comprises the following steps: feeding propylene, aqueous hydrogen peroxide and an organic solvent into a reactive distillation column 13 to perform contact reaction with an oxidation catalyst under an epoxidation condition, rising unreacted gas-phase propylene to pass through a packing layer 1 for further distillation and gas-liquid separation (the temperature of the packing layer is controlled to be 38-45 ℃), and finally discharging the gas-phase propylene from a gas-phase outlet 13.1 at the top of the column; the method comprises the following steps that (1) liquid-phase materials in the tower undergo catalytic reaction when flowing downwards through a catalyst bed layer 3, wherein the catalyst bed layer 3 has a three-layer structure, the discharging temperature of the uppermost layer is controlled to be 43-47 ℃, the discharging temperature of the middle layer is controlled to be 48-52 ℃, and the discharging temperature of the lowermost layer is controlled to be 58-62 ℃; the concentration of the propylene in the liquid phase of the uppermost layer is controlled to be 48-52 wt%, the concentration of the propylene in the liquid phase of the middle layer is controlled to be 23-27 wt%, and the concentration of the propylene in the liquid phase of the lowermost layer is controlled to be less than 3 wt%. The pressure of the reactive distillation column 13 is controlled to be 1.8-2.3 MPaG. The pressure drop of the gas phase communicating pipe 4 is not more than 5kPaG, the gas phase load proportion from top to bottom is gradually reduced, and the gas phase load mass proportion of the gas phase communicating pipe 4 from top to bottom in the three catalyst bed layers 3 is 1:0.5: 0.3.

Gas-phase propylene is discharged from the top of the reactive rectifying tower 13, liquid-phase reaction materials are discharged from the bottom of the reactive rectifying tower, wherein the gas-phase propylene (with the temperature of 40-45 ℃) is firstly sent into a condenser 9 for condensation and cooling to below 40 ℃, the separated liquid-phase propylene is sent into a liquid separation tank 11, and the liquid-phase propylene (with the purity reaching 99%) led out from the bottom of the liquid separation tank 11 is circularly returned to the filling section 1 and the catalyst bed layer 3 of the reactive rectifying tower 13 through a reflux pump 12 for controlling the temperature in the tower and participating in the reaction. The gas phase separated by the condenser 9 and the gas phase separated in the liquid separating tank 11 are sent to the deep cooler 10 for further cooling and liquid phase propylene recovery, and the gas phase discharged from the deep cooler 10 is sent to the next process.

The liquid phase reaction product (at 65 ℃, wherein the propylene content is less than 3 wt%, the epoxypropylene content is 17 wt%, and the balance is methanol and water) discharged from the bottom of the reactive distillation column 13 is sent to the downstream process.

Claims (10)

1. The utility model provides a system for reaction rectification production propylene oxide, includes the reaction rectifying column, its characterized in that, there is gaseous phase propylene export reaction rectifying column top, and there is liquid phase product export bottom, and the lateral wall has feed inlet and propylene circulation to import, and the upper segment of reaction rectifying column is equipped with and is located the packing layer of feed inlet top, the middle section are equipped with the catalyst bed who is located the feed inlet below, gaseous phase propylene export in proper order through condenser, knockout drum with propylene circulation access connection.

2. The reactive distillation propylene oxide production system of claim 1, wherein the catalyst bed has a multi-layer structure.

3. The system for producing propylene oxide by reactive distillation according to claim 1, wherein a gas phase communicating tube is connected between each bed.

4. The reactive distillation propylene oxide production system of claim 2, wherein the catalyst bed is a three layer structure.

5. The system for producing propylene oxide by reactive distillation according to claim 1, wherein a feed shower connected to the feed inlet is provided above the catalyst bed.

6. The reactive distillation propylene oxide production system of claim 1, wherein the propylene recycle inlet comprises a first propylene recycle inlet disposed above the packing layer and a second propylene recycle inlet disposed at the catalyst bed.

7. The system for producing propylene oxide by reactive distillation according to claim 6, wherein a circulating spray pipe connected with the first propylene circulating inlet is arranged above the packing layer.

8. The system for producing propylene oxide by reactive distillation according to claim 1, wherein the gas phase outlets of the condenser and the liquid separation tank are connected to the inlet of a chiller, and the liquid phase outlet of the chiller is connected to the liquid separation tank.

9. The reactive distillation propylene oxide production system of any one of claims 1-8, further comprising a regeneration system comprising a shell side or tube side of a regeneration heat exchanger and a recycle regeneration heater connected to the second propylene recycle inlet on the sidewall of the reactive distillation column.

10. The reactive distillation propylene oxide production system of claim 9, wherein the liquid product outlet at the bottom of the reactive distillation column is further connected to the tube side or the shell side of the regenerator via a circulation pump.

Images