CN104447243A - Reactive distillation method and device for butyraldehyde synthesis by low-pressure carbonyl - Google Patents

Abstract

The invention relates to a reactive distillation method and device for low-pressure carbonylation of butyraldehyde. The gas phase outlet of the top condenser of the reactive distillation tower is connected to the lower feed port of the absorption tower, the liquid phase outlet is connected to the reflux feed port of the reactive distillation tower, and the discharge from the bottom of the tower enters the flash tower; the discharge from the bottom of the flash tower is the catalyst solution It is connected to the feed inlet of the upper part of the reaction section of the reactive distillation tower, and the outlet at the top of the tower is connected to the upper feed inlet of the absorption tower; the exhaust gas is discharged from the top of the absorption tower, and the crude butyraldehyde discharged from the bottom of the tower enters the feed inlet of the upper part of the stripping tower The synthetic gas enters the feed port at the bottom of the stripping tower, the gas outlet at the top of the stripping tower is connected to the feed port of the reactive distillation tower, and the bottom of the tower obtains a mixed butyraldehyde product. The oxo-synthesized butyraldehyde reaction and the butyraldehyde purification and rectification separation are two unit operations, which are organically coupled in one device and carried out at the same time. Through the operation of the absorption tower and the stripping tower, the gas phase after condensation at the top of the reactive distillation tower is recovered. Propylene, the recovery rate of propylene can reach 90%, and the mass purity of mixed butyraldehyde can reach 99%.

Description

Reactive distillation method and device for low-pressure carbonylation of butyraldehyde

technical field

The invention relates to the technical field of butyraldehyde production, in particular to a reactive distillation method and device for low-pressure carbonylation of butyraldehyde.

Background technique

Butyraldehyde is an intermediate of important organic chemical raw materials and an important raw material for the production of various fine chemical products. Butyraldehyde has two isomers, n-butyraldehyde and isobutyraldehyde, and n-butyraldehyde is mainly used in the production of n-butanol and 2-ethylhexanol, and is also used in the production of trimethylolpropane, polyvinyl butyral, etc. Fine chemical products; isobutyraldehyde is mainly used in the production of isobutanol, neopentyl glycol, condensation and esterification products 2,2,4-trimethylpentanediol, isobutyric acid, isobutyronitrile, etc.

There are many ways to synthesize butyraldehyde, such as acetaldehyde condensation, butanol oxidative dehydrogenation and oxo synthesis, among which oxo synthesis is the main method for synthesizing butyraldehyde. Oxo-synthesis of butyraldehyde is based on propylene and synthesis gas (composed of hydrogen and carbon monoxide with a molar ratio of 1.02 to 1.04) as raw materials, reacting in the presence of a catalyst to form butyraldehyde, and then separating butyraldehyde into n-butyraldehyde and isobutyraldehyde by distillation Butyraldehyde. The development of the oxo synthesis process of propylene has experienced the high-pressure cobalt method, the modified cobalt method and the low-pressure rhodium method. Because the low-pressure rhodium method has the advantages of low temperature, low pressure, fast reaction rate, less side reactions, and investment saving, it is currently the most widely used craft.

CN1135475 discloses a preparation method of aldehydes, which is characterized in that the liquid mixture flowing out of the carbonylation reaction zone is heated, and then it is supplied to the upper part of the gas-liquid contact tower, and is in convective contact with the carbon monoxide and hydrogen entering from the lower part to separate and recover unreacted olefins, and the recovered unreacted olefins together with carbon monoxide and hydrogen are supplied to the carbonylation reaction zone, and the output from the tower reactor passes through the separation catalyst to obtain the butyraldehyde product. CN1133278A discloses a kind of preparation method of butyraldehyde, adopts the operation aldehyde distillation column under the lower pressure condition, can obtain the aldehyde with substantially the same purity that can obtain with conventional method under relatively high pressure condition, wherein heat load control To a low level, the temperature at the bottom of the tower can be kept at a low level, so that the heat consumption from other steps can be effectively recovered, thereby reducing energy consumption. CN102115433A discloses a method for producing propionaldehyde by low-pressure oxo-synthesis of ethylene, and the raw material conversion rate calculated by ethylene is ≥90%. The content of propionaldehyde product is ≥99.5%, and the method of synthesizing propionaldehyde is also applicable to butyraldehyde.

At present, there have been reports on the reaction and separation of propylene carbonylation to butyraldehyde. The means of realization is to react in a reactor first. After the reaction is completed, the product must be separated from light components, catalysts and products through high and low pressure towers to obtain butyraldehyde. Aldehyde product, the catalyst solution is returned to the reactor. Reactive distillation technology is an increasingly widely used process intensification technology in the chemical industry that couples reaction and separation in the same equipment simultaneously, which can not only save equipment investment, but also reduce the cost of subsequent operations. At present, there are no relevant patents and reports on the reactive distillation technology applied in the oxo synthesis of butyraldehyde.

Contents of the invention

The purpose of the present invention is to provide a low-pressure oxo-synthetic reactive distillation method and device for butyraldehyde. Using the catalytic reactive distillation method provided by the present invention has the advantages of simple separation process, low equipment investment, convenient operation and low energy consumption. Etc.

The reactive distillation method and device for low-pressure carbonylation of butyraldehyde of the present invention are mainly composed of a reactive distillation tower, a flash tower, an absorption tower and a stripping tower, and the main product is butyraldehyde. The method and device of the present invention are characterized by the adoption of reactive distillation technology and equipment, while the low-pressure carbonylation reaction of propylene is carried out in the reactive distillation column, the separation of light components and butyraldehyde can be achieved, and the column can also be recovered through subsequent operations. Propylene in the top light component realizes full utilization of raw materials.

Technical scheme of the present invention is as follows:

The reactive distillation device for low-pressure carbonylation of butyraldehyde of the present invention comprises a reactive distillation tower, a flash tower, an absorption tower, a stripping tower, a condenser, a reboiler, a compressor, a pump, and related feed lines and connections above The pipeline of the equipment; the top of the reactive distillation tower is equipped with a condenser, and the bottom of the tower is equipped with a reboiler; the gas phase outlet of the top condenser of the reactive distillation tower is connected to the lower feed port of the absorption tower, and the liquid phase outlet is connected to the reactive distillation tower The feed inlet of the reflux, the discharge from the bottom of the tower enters the flash tower; the discharge from the bottom of the flash tower is the feed inlet connecting the catalyst solution to the upper part of the reaction section of the reactive distillation tower, and the outlet at the top of the tower is connected to the feed of the upper part of the absorption tower The waste gas is discharged from the top of the absorption tower, and the crude butyraldehyde discharged from the bottom of the tower enters the upper feed port of the stripping tower; the synthesis gas enters the feed port at the bottom of the stripping tower, and the gas outlet of the stripping tower top is connected to the reaction fine Distillation tower feed port, tower still obtains mixed butyraldehyde product.

The reactive distillation method of low-pressure carbonylation butyraldehyde of the present invention is: raw material propylene (S01) enters the lower part of the reaction section of reactive distillation column (T1), and raw material synthesis gas (S02) partly enters reactive distillation column (T1) reaction In the lower part of the section, part of the synthesis gas (S17) enters the bottom of the stripper; the gas phase (S03) at the top of the reactive distillation column (T1) enters the overhead condenser (E1) of the reactive distillation column, and after condensation, the gas phase (S04) enters the absorption At the bottom of the tower (T3), the condensed liquid phase (S05) is fully refluxed to the reactive distillation tower (T1), and the bottom of the reactive distillation tower (T1) is a mixed butyraldehyde and catalyst solution (S06) as a flash tower (T2 ) feed; flash tower (T2) tower top is mixed butyraldehyde gas (S07) enters condenser (E3) after condensation, enters pump (P2) pressurization and obtains mixed butyraldehyde liquid (S08) and enters absorption tower (T3) At the top of the flash tower (T2), the catalyst solution (S09) enters the condenser (E4) for cooling at the bottom of the flash tower (T2), and then the solution (S10) pressurized by the pump (P1) enters the reaction section of the reactive distillation tower (T1) The upper part; the gas (S13) at the top of the absorption tower (T3) goes to the fuel zone, and the crude butyraldehyde (S11) extracted from the bottom of the tower enters the pump (P3) and the pressurized crude butyraldehyde solution (S12) enters the stripping tower (T4) The upper part; syngas (S17) and crude butyraldehyde solution (S12) countercurrently contact in stripper (T4), and the gas (S15) of the top gas (S15) of stripper (T4) passes through compressor (C1) behind the gas ( S16) can be used as a raw material to return to the reactive distillation column (T1) feed, and the mixed butyraldehyde product (S14) is extracted from the bottom of the stripping column (T4).

In the reactive distillation method of low-pressure carbonylation of butyraldehyde: the pressure of the reactive distillation tower is 1.7-1.9Mpa, the temperature of the reaction section is 80-110°C, the catalyst is rhodium-triphenylphosphine, and the solvent is the trimer of butyraldehyde, also N-butyraldehyde can be used as a solvent, the mass fraction of rhodium in the reaction solution is 250-450ppm, the mass fraction of triphenylphosphine is 8-12%, and the molar ratio of propylene to syngas in the feed composition is 1:2-1:3 The pressure of the flash tower is 0.1-1Mpa; the pressure of the absorption tower is 0.1-1Mpa; the pressure of the stripper is 0.1-3Mpa, and the molar ratio of crude butyraldehyde solution to synthesis gas is 1:1; the pressure in this article means absolute pressure.

The low-pressure oxo-synthesis of butyraldehyde reactive distillation method and device of the present invention has the advantage that two unit operations, the oxo-synthesis of butyraldehyde reaction and the separation of butyraldehyde purification and rectification, are organically coupled in one device and carried out at the same time. The separation of light components and butyraldehyde not only saves equipment investment, but also reduces subsequent operating costs. The separation of mixed butyraldehyde and catalyst solution can be realized through flash tower. Through the operation of the absorption tower and the stripping tower, the propylene in the gas phase after condensation at the top of the reactive distillation tower can be recovered, the recovery rate of the propylene can reach 90%, and the mass purity of the mixed butyraldehyde can reach 99%.

Description of drawings

Figure 1 is a schematic diagram of a reactive distillation method and device for low-pressure oxo-synthesis of butyraldehyde.

Equipment: T1. Reactive distillation tower, T2. Flash tower, T3. Absorption tower, T4. Stripper, P1. Catalyst solution circulation pump, P2. Flash tower top extraction pump, P3. Absorption tower bottom Production pump, E1. Reactive distillation column condenser, E2. Reboiler of reactive distillation column, E3. Flash tower top material condenser, E4. Flash column bottom material condenser, C1. Compressor

Logistics: S01. Raw material propylene, S02. Raw material synthesis gas, S03. Reactive distillation tower top gas, S04. Reactive distillation tower top condensed gas phase, S05. Reactive distillation tower top condensed liquid phase, S06. Mix butyraldehyde and catalyst solution, S07. Mix butyraldehyde gas, S08. Mix butyraldehyde liquid, S09. Catalyst solution, S10. Catalyst solution after pump pressurization, S11. Crude butyraldehyde solution extracted from the bottom of the absorption tower, S12. Crude butyraldehyde solution after pump pressurization, S13. Absorption tower overhead gas, S14. Mixed butyraldehyde product, S15. Stripping tower overhead gas, S16. Tower overhead gas after compressor, S17. Syngas into the stripper

Detailed ways

The method and device provided by the present invention will be further described below in conjunction with the accompanying drawings.

The present invention is achieved through the following technical solutions:

Reactive distillation equipment for low-pressure carbonylation of butyraldehyde, including reactive distillation tower, flash tower, absorption tower, stripper, condenser, reboiler, compressor, pump, and related feed lines and pipelines connecting the above equipment A condenser is arranged on the top of the reactive distillation tower, and a reboiler is arranged on the bottom of the tower; the gas phase outlet of the condenser on the top of the reactive distillation tower is connected to the lower feed port of the absorption tower, and the liquid phase outlet is connected to the reflux feed of the reactive distillation tower outlet, the discharge from the bottom of the tower enters the flash tower; the discharge from the bottom of the flash tower is the catalyst solution connected to the feed inlet of the upper part of the reaction section of the reactive distillation tower, and the outlet at the top of the tower is connected to the feed inlet of the upper part of the absorption tower; The exhaust gas is discharged from the top of the tower, and the bottom discharge is crude butyraldehyde, which enters the upper feed port of the stripping tower; the synthesis gas enters the feed port at the bottom of the stripping tower, and the gas outlet at the top of the stripping tower is connected to the feed inlet of the reactive distillation tower. The feed port and the tower kettle are mixed butyraldehyde products.

The reactive distillation method of low-pressure carbonylation butyraldehyde of the present invention is: raw material propylene (S01) enters the lower part of the reaction section of reactive distillation column (T1), and raw material synthesis gas (S02) partly enters reactive distillation column (T1) reaction In the lower part of the section, part of the synthesis gas (S17) enters the bottom of the stripper; the gas phase (S03) at the top of the reactive distillation column (T1) enters the overhead condenser (E1) of the reactive distillation column, and after condensation, the gas phase (S04) enters the absorption At the bottom of the tower (T3), the condensed liquid phase (S05) is fully refluxed to the reactive distillation tower (T1), and the bottom of the reactive distillation tower (T1) is a mixed butyraldehyde and catalyst solution (S06) as a flash tower (T2 ) feed; flash tower (T2) tower top is mixed butyraldehyde gas (S07) enters condenser (E3) after condensation, enters pump (P2) pressurization and obtains mixed butyraldehyde liquid (S08) and enters absorption tower (T3) At the top of the flash tower (T2), the catalyst solution (S09) enters the condenser (E4) for cooling at the bottom of the flash tower (T2), and then the solution (S10) pressurized by the pump (P1) enters the reaction section of the reactive distillation tower (T1) The upper part; the gas (S13) at the top of the absorption tower (T3) goes to the fuel zone, and the crude butyraldehyde (S11) extracted from the bottom of the tower enters the pump (P3) and the pressurized crude butyraldehyde solution (S12) enters the stripping tower (T4) The upper part; syngas (S17) and crude butyraldehyde solution (S12) countercurrently contact in stripper (T4), and the gas (S15) of the top gas (S15) of stripper (T4) passes through compressor (C1) behind the gas ( S16) can be used as a raw material to return to the reactive distillation column (T1) feed, and the mixed butyraldehyde product (S14) is extracted from the bottom of the stripping column (T4).

In the reactive distillation method of low-pressure carbonylation of butyraldehyde, the pressure of the reactive distillation tower is 1.7-1.9Mpa, the temperature of the reaction section is 80-110°C, the catalyst is rhodium-triphenylphosphine, and the solvent is a trimer of butyraldehyde, which can also be Using n-butyraldehyde as a solvent, the mass fraction of rhodium in the reaction solution is 250-450ppm, the mass fraction of triphenylphosphine is 8-12%, and the molar ratio of propylene to synthesis gas is 1:2-1:3; The pressure of the flash tower is 0.1-1Mpa; the pressure of the absorption tower is 0.1-1Mpa; the pressure of the stripper is 0.1-3Mpa, and the molar ratio of crude butyraldehyde solution to synthesis gas is 1:1.

Example 1

In this example, the pressure of the reactive distillation tower is 1.7Mpa, the temperature of the reaction section is 110°C, the catalyst is rhodium-triphenylphosphine, the solvent is the trimer of butyraldehyde, the mass fraction of rhodium in the reaction solution is 250ppm, and the triphenylphosphine The mass fraction of phosphine is 8%, the molar ratio of feed composition propylene and synthesis gas is 1:2; the pressure of flash tower is 1Mpa; the pressure of absorption tower is 0.6Mpa; the pressure of stripper is 3Mpa, the crude butyraldehyde solution and synthesis gas The molar ratio is 1:1. Finally, the recovery rate of propylene in the non-condensable gas at the top of the reactive distillation column was 92%, and the mass purity of mixed butyraldehyde was 99%.

Example 2

In this example, the pressure of the reactive distillation tower is 1.9Mpa, the temperature of the reaction section is 80°C, the catalyst is rhodium-triphenylphosphine, the solvent is a trimer of butyraldehyde, the mass fraction of rhodium in the reaction solution is 350ppm, and the triphenylphosphine The mass fraction of phosphine is 12%, the molar ratio of feed composition propylene and synthesis gas is 1:3; the pressure of the flash tower is 0.1Mpa; the pressure of the absorption tower is 1Mpa; The gas molar ratio is 1:1. Finally, the recovery rate of propylene in the non-condensable gas at the top of the reactive distillation column was 93%, and the mass purity of mixed butyraldehyde was 99.5%.

Example 3

In this example, the pressure of the reactive distillation column is 1.8Mpa, the temperature of the reaction section is 100°C, the catalyst is rhodium-triphenylphosphine, the solvent is a trimer of butyraldehyde, the mass fraction of rhodium in the reaction solution is 450ppm, and the triphenylphosphine The mass fraction of phosphine is 10%, the molar ratio of feed composition propylene to synthesis gas is 1:2.5; the pressure of flash tower is 0.5Mpa; the pressure of absorption tower is 0.1Mpa; the pressure of stripping tower is 1Mpa, the crude butyraldehyde solution and synthesis The gas molar ratio is 1:1. Finally, the recovery rate of propylene in the non-condensable gas at the top of the reactive distillation column is 90%, and the mass purity of mixed butyraldehyde is 99.2%.

Claims (7)

1. A reactive distillation device for low-pressure carbonylation of butyraldehyde, comprising a reactive distillation tower, a flash tower, an absorption tower, a stripping tower, a condenser, a reboiler, a compressor, a pump, and related feed lines and connections The pipeline of the above equipment; it is characterized in that a condenser is arranged at the top of the reactive distillation tower, and a reboiler is arranged at the bottom of the tower; the gas phase outlet of the condenser at the top of the reactive distillation tower is connected to the lower feed port of the absorption tower, and the liquid phase outlet is connected to Reactive distillation tower reflux inlet, tower bottom discharge into the flash tower; flash tower bottom discharge is the catalyst solution connected to the feed inlet of the upper part of the reaction section of the reactive distillation tower, the tower top outlet is connected to the absorption tower The upper feed port; the waste gas is discharged from the top of the absorption tower, and the bottom discharge is crude butyraldehyde, which enters the upper feed port of the stripper; the synthesis gas enters the feed port at the bottom of the stripper, and the gas outlet at the top of the stripper It is connected to the feed port of the reactive distillation tower, and the bottom of the tower can obtain mixed butyraldehyde products. 2. adopt the device of claim to carry out the reactive distillation method of low-pressure carbonylation butyraldehyde: it is characterized in that raw material propylene enters the bottom of the reaction section of reactive distillation tower, and a part of raw material synthesis gas enters the bottom of reactive distillation tower reaction section, and a part synthesizes The gas enters the bottom of the stripping tower; the gas phase at the top of the reactive distillation tower enters the condenser at the top of the reactive distillation tower, and after condensation, the gas phase enters the bottom of the absorption tower, and after condensation, the liquid phase returns to the reactive distillation tower. The bottom of the tower is the mixed butyraldehyde and catalyst solution as the feed of the flash tower; the top of the flash tower is the mixed butyraldehyde gas entering the condenser, and after condensation, it enters the pump and pressurizes to obtain the mixed butyraldehyde liquid into the top of the absorption tower, flash evaporates At the bottom of the tower, the catalyst solution enters the condenser to cool down, and then the solution pressurized by the pump enters the upper part of the reaction section of the reactive distillation tower; the gas at the top of the absorption tower goes to the fuel area, and the crude butyraldehyde extracted from the bottom of the tower enters the pump after pressurization The thick butyraldehyde solution enters the upper part of the stripping tower; the synthesis gas and the thick butyraldehyde solution are countercurrently contacted in the stripping tower, and the gas at the top of the stripping tower is returned to the reactive distillation tower as a raw material through the gas after the compressor, Mixed butyraldehyde products are extracted from the bottom of the stripping tower. 3. The method according to claim 2, characterized in that the reactive distillation column pressure is 1.7-1.9Mpa, and the reaction zone temperature is 80-110°C. 4. method as claimed in claim 2 is characterized in that. Catalyst is rhodium-triphenylphosphine, and solvent is the terpolymer of butyraldehyde; Or adopt n-butyraldehyde to make solvent, and the massfraction of rhodium in the reaction solution is 250 -450ppm, the mass fraction of triphenylphosphine is 8-12%, and the molar ratio of propylene to syngas in feed composition is 1:2-1:3. 5. The method according to claim 2, characterized in that the flash column pressure is 0.1-1Mpa. 6. The method according to claim 2, characterized in that the absorption tower pressure is 0.1-1Mpa. 7. The method according to claim 2, characterized in that the stripping tower pressure is 0.1-3Mpa, and the thick butyraldehyde solution and synthesis gas molar ratio is 1:1.