CN115007099A

CN115007099A - Oxo-synthesis reactor and working method thereof

Info

Publication number: CN115007099A
Application number: CN202210586906.0A
Authority: CN
Inventors: 帅云; 樊茁钦; 黄正梁; 杨遥; 王靖岱; 阳永荣
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2022-05-26
Filing date: 2022-05-26
Publication date: 2022-09-06
Anticipated expiration: 2042-05-26
Also published as: CN115007099B

Abstract

The invention discloses a oxo reactor and a working method thereof, wherein the oxo reactor comprises a reactor shell, at least one liquid inlet tangent to the shell, a top liquid inlet, a gas outlet, a CO inlet, a circulating liquid outlet and a reaction liquid outlet; the end part of the top liquid inlet is provided with a nozzle; and a nozzle is arranged at the end part of the CO inlet. According to the invention, the pulse jet of the CO gas is matched with the vortex motion of the mixed liquid, so that the uniform distribution of the CO gas and the raw material liquid in the reaction kettle is realized, the problem of mechanical seal leakage in mechanical stirring is avoided, the maintenance cost of equipment is reduced, the gas-liquid mixed mass transfer effect in the reactor is enhanced, the reaction rate and the raw material utilization rate are improved, and the long-term stable operation of the device is ensured.

Description

Oxo-synthesis reactor and working method thereof

Technical Field

The invention relates to the technical field of petrochemical industry and coal chemical industry, in particular to a carbonyl synthesis reactor and a working method thereof.

Background

Acetic acid is used as an important chemical intermediate and a chemical product, and is mainly used for producing vinyl acetate monomers, terephthalic acid, acetate esters, acetic anhydride, halogenated acetic acid, cellulose acetate, other acetic acid derivatives and the like. In addition, the acetic acid can be further processed into various products such as pesticides, medicines, dyes, synthetic fibers, adhesives and the like. The methanol oxo-synthesis method is a main method for industrially producing acetic acid, liquid-phase methanol feeding and gas-phase CO feeding are used for synthesizing the acetic acid in a catalyst system, and the acetic acid produced by the method accounts for more than 80 percent of the total production of the global acetic acid and becomes a main process for producing the acetic acid. Mechanical stirring is mostly adopted in a reactor used for synthesizing acetic acid by carbonyl in the prior art, because the methanol carbonyl reaction is a strong corrosive environment, equipment is easy to corrode, an imported zirconium material is needed, the manufacturing and maintenance costs of a stirring kettle are high, and meanwhile, the mechanical stirring has the problems of large vibration and easy leakage in sealing, is difficult to stably and safely operate for a long time, and a gas-liquid mixing means for replacing the stirring kettle is needed to be found.

In response to this problem, in recent years, the use of fluid agitation instead of mechanical agitation has been an important direction of improvement. It is known from patents CN202020145192.6 and CN202110014036.5 that the reaction raw material and the circulating mother liquor can be mixed by mechanical stirring by combining the reaction circulating liquid injected from a plurality of diameter-reducing nozzles near the wall with a gas distributor. Patent CN201320103329.1 and CN201310072175.9 describe that the central nozzle at the bottom of the reaction kettle can mix the gas phase and the liquid phase under the action of the circular ring-shaped gas distributor, so as to promote mass transfer of the gas phase and the liquid phase, but the vertically upward jet flow has a limited dispersion effect on the gas bubbles in the radial direction, and the effect is not ideal. CN201811224192.9 describes that at least two nozzles near the inner wall are arranged at the top of the reaction kettle, and a gas distributor is arranged at the bottom of the reaction kettle, so as to realize the purpose of fluid stirring. The eccentric arrangement of shower nozzle produces the bias current phenomenon, has leaded to the gas-liquid dispersion in the reactor uneven, and stirring effect is poor than traditional stirred tank's stirring effect.

In conclusion, the fluid stirring technology used at present is poor in stirring effect compared with the traditional mechanical stirring technology, low in gas-liquid mixing degree and low in production efficiency of the device.

Disclosure of Invention

Aiming at the technical problems in the prior art, the invention aims to provide a oxo-synthesis reactor and a working method thereof.

The invention can be realized by the following technical scheme:

the invention firstly provides a carbonyl synthesis reactor, which comprises a reactor shell, at least one liquid inlet tangent to the shell, a top liquid inlet, a circulating liquid outlet, a reaction liquid outlet, a gas outlet and two CO inlets; the end parts of the two CO inlets positioned in the reactor shell are respectively provided with a first nozzle and a second nozzle; the outlets of the first nozzle and the second nozzle are arranged in opposite directions and are positioned on the same vertical line.

In a preferred embodiment of the present invention, the CO flow rates at the outlets of the first nozzle and the second nozzle are periodically changed at a certain pulse frequency, and the first nozzle and the second nozzle have a phase difference of pi.

As a preferable mode of the present invention, the end of the liquid inlet located in the reactor shell is provided with a third nozzle; the outlets of the first nozzle and the third nozzle are vertically downward, and the outlet of the second nozzle is vertically upward.

In a preferred embodiment of the present invention, the outlet of the third nozzle is located 0.1 to 0.5 times the liquid level below the liquid surface.

As a preferable aspect of the present invention, the liquid inlet is disposed at a height between the first nozzle and the second nozzle.

In a preferred embodiment of the present invention, there are 3 liquid inlets located at the same height of the reactor shell, and the 3 liquid inlets are located at 120 ° to each other in the circumferential direction.

As a preferred scheme of the invention, the 3 liquid inlets are a methanol liquid inlet, a catalyst mother liquor liquid inlet and a dilute acid mixed liquid inlet respectively.

As a preferable scheme of the invention, the reactor shell consists of a reaction kettle barrel and upper and lower hemispherical/ellipsoidal heads.

In a preferred embodiment of the present invention, the distance between the first nozzle and the second nozzle is 0.01 to 0.2 times the diameter of the reaction vessel.

In a preferred embodiment of the present invention: the circulating liquid outlet and the reaction liquid outlet are positioned below the liquid inlet tangent to the shell.

Preferably, the recycle liquid outlet is located at the bottom of the reactor.

In the technical scheme of the invention: the liquid inlet tangent to the shell is located at the position, from the bottom 1/2 to the bottom 1/3, of the cylinder body.

The technical scheme of the invention is as follows: and a rotator is arranged on the liquid inlet tangent to the shell.

Preferably, the radial thickness of the rotor is 0.03-0.2 times of the diameter of the reaction kettle.

Preferably, the nozzle diameter of the end nozzle of the CO inlet is 0.01-0.1 times of the diameter of the reaction kettle.

Preferably, the nozzle spacing of the end nozzle of the CO inlet is 0.01-0.2 times of the diameter of the reaction kettle.

In the technical scheme of the invention, the CO flow at the outlet of the nozzle at the CO inlet end part is changed at a certain pulse frequency, and the CO flow have a phase difference pi.

Preferably, the CO flow rate change frequency is 2-20 Hz.

In the technical scheme of the invention, the port nozzle of the top liquid inlet is positioned below the liquid level.

Preferably, the port nozzle of the top liquid inlet is located at a height of 0.1-0.5 times liquid level below liquid level.

Preferably, the nozzle flow velocity at the end of the CO inlet is 8-25 m/s.

Preferably, the nozzle flow velocity at the top liquid inlet end is 8-25 m/s.

Preferably, the flow velocity of the liquid in the spinner is 5-15 m/s.

The invention also provides an oxo synthesis method based on the reactor, which comprises the following steps:

CO gas enters the reactor from two CO inlets and is oppositely sprayed at a first nozzle and a second nozzle; the CO flow rates of the outlets of the first nozzle and the second nozzle are periodically changed at a certain pulse frequency, the first nozzle and the second nozzle have a phase difference pi, and the change of the flow rates of the first nozzle and the second nozzle enables the sprayed CO gas to swing up and down to generate a large amount of small CO bubbles and promote the uniform distribution of the CO gas in the whole reaction kettle;

methanol, catalyst mother liquor and dilute acid mixed liquor respectively enter the reactor from three liquid inlets along the tangential direction of the shell; the gas flows in a vortex mode under the action of the cyclone, and moves tangentially with small CO bubbles, and the bubbles form smaller bubbles under the shearing action, so that the gas-liquid mass transfer process is facilitated;

the top methanol liquid jet flow stirs the mixed liquid, so that the CO gas is uniformly distributed, and meanwhile, the settled methanol liquid and the rising CO gas move up and down mutually, and the two are uniformly mixed, thereby being beneficial to the promotion of the reaction rate.

Compared with the prior art, the invention has the beneficial effects that: according to the invention, the CO gas pulse is sprayed oppositely, the mixed solution flows in a vortex manner, the methanol feeding solution is stirred in a jet manner and is matched with the spinner, so that the distribution of the CO gas and the raw material solution in the reaction kettle is improved. No traditional stirring part exists in the whole reaction kettle, the problem of mechanical seal leakage in mechanical stirring is solved, the safe operation of the device is guaranteed, the maintenance and replacement of the stirring kettle are avoided, the maintenance cost is reduced, and the power consumption of the device is reduced. The high-speed gas is sprayed to form micro bubbles, and the bubbles in the reaction kettle are further reduced under the shearing action of the vortex liquid, so that the gas-liquid mass transfer efficiency and speed are improved, and the productivity is improved.

Drawings

FIG. 1 is a schematic diagram of the structure of an oxo reactor provided by the present invention.

Fig. 2 is a schematic structural diagram of a spinner provided by the invention.

Fig. 3 is a schematic view of a nozzle structure according to the present invention.

Wherein: 1-a reactor shell; 2-a spinner; 3-at least one liquid inlet tangential to the housing; 4-reaction liquid outlet; 5-a circulating liquid outlet; 6-upper CO inlet; 7-lower CO inlet; 8-third nozzle (top liquid inlet end nozzle); 9-gas outlet; 10-top liquid inlet; 11-first nozzle (upper CO inlet end nozzle); 12-second nozzle (lower CO inlet end nozzle).

Detailed Description

The oxo reactor provided by the present invention is further illustrated by the following examples, but the scope of the invention is not limited thereto:

FIG. 1 shows an oxo reactor provided by the present invention, which comprises a reactor shell 1, a spinner 2, at least one liquid inlet 3 tangential to the shell, a reaction liquid outlet 4, a recycle liquid outlet 5, an upper CO inlet 6, a lower CO inlet 7, a gas outlet 9, and a top liquid inlet 10; the reactor main body consists of a reaction kettle cylinder and upper and lower hemispherical/ellipsoidal seal heads; the liquid inlets 3 are respectively a methanol liquid inlet, a catalyst mother liquor inlet and a dilute acid mixed liquid inlet, are positioned at the same height of the reactor shell and form an angle of 120 degrees with each other, and are tangent to the shell; a third nozzle 8 is arranged at the port of the top liquid inlet positioned in the reaction kettle; a first nozzle 11 is arranged at the port of the upper CO inlet positioned in the reaction kettle; a second nozzle 12 is arranged at the port of the lower CO inlet positioned in the reaction kettle; the outlets of the third nozzle 8 and the first nozzle 11 are vertically downward, the outlet of the second nozzle 12 is vertically upward, and the first nozzle 11 and the second nozzle 12 are oppositely arranged and are positioned on the same vertical line; the liquid inlet 3 is axially positioned between the first nozzle 11 and the second nozzle 12; the CO flow rates at the outlets of the first nozzle 11 and the second nozzle 12 periodically change at a certain frequency, and the two nozzles have a phase difference of pi, and the change periods of the two nozzles are the same. Circulating liquid flows out from the circulating liquid outlet 5, is cooled by an external circulating heat exchanger and then returns to the reaction kettle through the top liquid inlet 10 or the liquid inlet 3; methanol raw material liquid, catalyst mother liquor and dilute acid mixed liquid respectively enter the reactor from three liquid inlets 3 along the tangential direction of the shell. Wherein, the catalyst mother liquor refers to the liquid returned to the reaction kettle from the bottom of the flash tank. Under the conditions of reaction pressure of 2.8MPa and temperature of 190 ℃, methanol and CO which are introduced into the reaction kettle react under the action of a catalyst to generate acetic acid, and a small amount of by-product methyl acetate is generated at the same time.

The upper and lower CO gas streams are sprayed oppositely, the gas is sputtered from the center to the periphery through impact dispersion, and meanwhile, as the two streams have a phase difference pi, when the flow of the upper gas inlet is maximum, the flow of the lower gas inlet is minimum. When the lower inlet flow is minimum, the upper inlet flow is maximum. The change of the two gases causes the splashed gas to swing up and down, a large amount of small bubbles are generated in the mixed liquid, and the uniform distribution of CO gas in the whole reaction kettle is facilitated. The mixed liquid is introduced from two sides, flows in a vortex type under the action of the cyclone, moves in a tangent mode with the small bubbles, and forms smaller bubbles under the shearing action, so that the gas-liquid mass transfer process is facilitated, and the reaction rate is increased. The top methanol liquid jet flow stirs the mixed liquid, so that the CO gas is uniformly distributed, and meanwhile, the sinking methanol liquid and the rising CO gas mutually move up and down, and the two are uniformly mixed, thereby being beneficial to the promotion of the reaction rate.

As a specific implementation method, the CO flow control manner of the first nozzle 11 and the second nozzle 12 is a sine function.

As a specific implementation method, the liquid inlet 3 is positioned at the position from 1/2 to 1/3 of the bottom of the cylinder; the radial thickness of the rotor 2 is 0.03-0.2 times of the diameter of the reaction kettle; the nozzle diameters of the upper CO inlet end nozzle 11 and the lower CO inlet end nozzle 12 are 0.01-0.1 time of the diameter of the reaction kettle; the nozzle spacing between the upper CO inlet end nozzle 11 and the lower CO inlet end nozzle 12 is 0.01-0.2 times of the diameter of the reaction kettle; the outlet of the nozzle 8 is positioned below the liquid level of the reaction kettle, and preferably 0.1-0.5 time of the liquid level height below the liquid level; the CO flow rates at the outlets of the nozzle 11 and the nozzle 12 are changed at a certain frequency, the two have a phase difference pi, and the preferred change frequency is 2-20 Hz.

In a preferred embodiment, the outlet flow rate of the top liquid inlet port nozzle 8 is 8-25 m/s.

In a preferred embodiment, the CO inlet port nozzle 11 and nozzle 12 outlet flow rates are 8-25 m/s.

In a preferred embodiment, the flow rate of the liquid in the spinner is 5-15 m/s.

Example 1

The oxo reactor shown in figure 1 is adopted, the height of the reaction kettle barrel is 5m, the diameter is 3m, the diameter of the hemispherical end socket is 3m, and the height of the liquid level of the reaction kettle is 5.5 m. The diameter of the screw driver (as shown in FIG. 2) was 2.4m, the diameters of the nozzles of the upper CO inlet end nozzle 11 and the lower CO inlet end nozzle 12 were 100mm, the nozzle pitch between the upper CO inlet end nozzle 11 and the lower CO inlet end nozzle 12 was 200mm, and the outlet of the nozzle 8 was 1.2m below the liquid surface of the reactor. The CO flow at the outlets of the

nozzles

11 and 12 changes at a pulse frequency of 5Hz, the two nozzles have a phase difference pi, and the outlet flow velocity change range of the two nozzles is 8-15 m/s; the outlet flow velocity of the top liquid inlet port nozzle 8 is 8 m/s; methanol raw material liquid, catalyst mother liquor and dilute acid mixed liquid respectively enter the reactor from three liquid inlets 3 along the tangential direction of the shell, and flow in a vortex mode under the action of the cyclone, and the flow speed of liquid in the cyclone is 10 m/s. Circulating liquid flows out from a circulating liquid outlet 5, is cooled by an external circulating heat exchanger and then enters the reaction kettle through a top liquid inlet 10, CO gas raw materials enter the reaction kettle from an upper CO inlet 6 and a lower CO inlet 7, and reaction liquid is discharged from a reaction liquid outlet 4. Under the conditions that the reaction pressure is 2.8MPa and the temperature is 190 ℃, in a catalyst system, the methanol and the CO generate acetic acid and generate a small amount of methyl acetate, and the operation result shows that the reaction kettle operates stably, the temperature fluctuation at the bottom of the reaction kettle is within 2 ℃, and the content of the byproduct methyl acetate is 0.52%.

Comparative example 1

At the same temperature, pressure and catalytic system as in example 1, the only difference from example 1 is that the CO all enters the reactor from nozzle 12; methanol raw material liquid, catalyst mother liquor and dilute acid mixed liquid directly enter the reactor from three liquid inlets 3 along the tangential direction of the shell respectively. The operation result shows that the operation fluctuation of the reaction kettle is large, the temperature fluctuation at the bottom of the reaction kettle is within 8-10 ℃, and the content of the byproduct methyl acetate is 1.54%.

Example 2

At the same temperature, pressure and catalyst system as in example 1, the only difference from example 1 is that the spacing between the upper CO inlet end nozzle 11 and the lower CO inlet end nozzle 12 is 500 mm. The operation result shows that the reaction kettle operates stably, the temperature fluctuation at the bottom of the reaction kettle is within 4 ℃, and the content of the byproduct methyl acetate is 0.78%.

Example 3

The only difference from example 1 is that the CO flow at the outlet of nozzle 11 and nozzle 12 is varied at a pulse frequency of 10Hz and the outlet flow rate of the top liquid inlet port nozzle 8 is 12m/s, at the same temperature, pressure and catalytic system as in example 1. The operation result shows that the reaction kettle operates stably, the temperature fluctuation at the bottom of the reaction kettle is within 1 ℃, and the content of the byproduct methyl acetate is 0.42 percent.

The above-mentioned embodiments are merely preferred embodiments of the present invention, and not intended to limit the present invention, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention, and the technical contents of the present invention, which are claimed, are all described in the claims.

Claims

1. An oxo reactor, characterized by comprising a reactor shell (1), at least one liquid inlet (3) tangential to the shell, a top liquid inlet (10), a circulating liquid outlet (5), a reaction liquid outlet (4), a gas outlet (9), and two CO inlets; the ends of the two CO inlets positioned in the reactor shell (1) are respectively provided with a first nozzle (11) and a second nozzle (12); the outlets of the first nozzle (11) and the second nozzle (12) are arranged oppositely and positioned on the same vertical line.

2. Reactor according to claim 1, characterized in that the CO flow at the outlet of the first nozzle (11) and the second nozzle (12) varies periodically with a certain pulse frequency, with a phase difference of pi.

3. A reactor according to claim 1, characterized in that the end of the liquid inlet (10) located in the reactor shell (1) is provided with a third nozzle (8); the outlets of the first nozzle (11) and the third nozzle (8) are vertically downward, and the outlet of the second nozzle (12) is vertically upward.

4. A reactor according to claim 3, characterized in that the outlet of the third nozzle (8) is located 0.1-0.5 times the level below the liquid surface.

5. Reactor according to claim 1, characterized in that the liquid inlet (3) is arranged at a height between the first nozzle (11) and the second nozzle (12).

6. A reactor according to any one of claims 1-5, characterized in that the liquid inlets (3) are provided in 3 and located at the same height of the reactor shell, the 3 liquid inlets (3) being located at 120 ° to each other in the circumferential direction.

7. The reactor according to claim 6, wherein the 3 liquid inlets (3) are a methanol inlet, a catalyst mother liquor inlet and a dilute acid mixed liquor inlet respectively.

8. A reactor according to claim 1, characterized in that the reactor shell (1) consists of a reactor vessel and upper and lower hemispherical/ellipsoidal heads.

9. The reactor according to claim 1, wherein the distance between the first nozzle (11) and the second nozzle (12) is 0.01-0.2 times the diameter of the reaction kettle.

10. An oxo process based on the reactor of claim 6,

CO gas enters the reactor from two CO inlets and is oppositely sprayed at a first nozzle (11) and a second nozzle (12); the CO flow rates of the outlets of the first nozzle (11) and the second nozzle (12) are periodically changed at a certain pulse frequency, the phase difference phi exists between the first nozzle and the second nozzle, and the change of the flow rates of the first nozzle (11) and the second nozzle (12) enables the sprayed CO gas to swing up and down to generate a large amount of small CO bubbles and promote the uniform distribution of the CO gas in the whole reaction kettle;

methanol, catalyst mother liquor and dilute acid mixed liquor respectively enter the reactor from three liquid inlets (3) along the tangential direction of the shell; the gas flows in a vortex mode under the action of the cyclone, and moves tangentially with small CO bubbles, and the bubbles form smaller bubbles under the shearing action, so that the gas-liquid mass transfer process is facilitated;