Gas-liquid mixed reactor, production system and application thereof in acetic acid synthesis

Abstract

The application belongs to the field of chemical synthesis, and discloses a gas-liquid mixed reactor, a production system and application thereof in acetic acid synthesis. The gas-liquid mixed reactor comprises a shell, a gas feeding pipe, a liquid feeding pipe, a gas distributor, a liquid distributor, a flow guide plate, a gas-liquid separator, a gas outlet and a liquid outlet. The production system comprises the gas-liquid mixed reactor. The gas-liquid mixed reactor and the production system can be used for acetic acid synthesis. The gas-liquid mixed reactor has no mechanical stirring, good gas-liquid mixing effect, and is suitable for acetic acid synthesis.

Description

Technical Field

[0001] This invention belongs to the field of chemical synthesis, and particularly relates to a gas-liquid mixing reactor, a production system, and its application in acetic acid synthesis. Background Technology

[0002] Currently, the commonly used technology for acetic acid production involves a gas-liquid mixing reaction of methanol and carbon monoxide in a reactor. Existing reactors often use mechanical stirring to achieve gas-liquid mixing; however, mechanical stirring has poor sealing properties, is prone to material leakage, has low reliability, and affects continuous industrial production.

[0003] To overcome the problems of mechanically stirred gas-liquid reactors, some studies have designed jet-type gas-liquid reactors. For example, CN104028178A discloses a method for enhancing the mixing effect of a hydraulic reactor. This hydraulic reactor includes an outlet, baffles, a liquid jetting device, an inlet, a gas distributor, an outlet, and an inlet. The inlet is located at the lower side of the reactor, the outlet at the top, and the inlet at the bottom. The outlets are symmetrically arranged on both sides of the lower head of the reactor. The gas distributor is located between the baffles and the liquid jetting device. This method achieves mixing of raw materials through a combination of gas-phase distributed feeding and liquid-phase jet feeding, along with the baffles. However, the baffles in this method can merge smaller bubbles into larger bubbles, resulting in poor gas-liquid contact.

[0004] Therefore, in view of the problem that the gas-liquid mixing effect of the existing technology is not ideal, there is an urgent need in the field for a gas-liquid mixing reactor and production system that does not require mechanical stirring, has a good gas-liquid mixing effect, is conducive to improving reaction efficiency and conversion rate, and is suitable for acetic acid synthesis. Summary of the Invention

[0005] The present invention aims to provide a mechanically stirred gas-liquid mixing reactor, production system and application suitable for the synthesis of acetic acid from methanol and carbon monoxide.

[0006] A first aspect of the present invention provides a gas-liquid mixing reactor, comprising:

[0007] case,

[0008] The gas feed pipe and liquid feed pipe pass through the lower part of the housing.

[0009] A gas distributor located at the bottom of the gas-liquid mixing reactor and connected to the gas feed pipe.

[0010] A liquid injection pipe or liquid distributor located at the bottom of the gas-liquid mixing reactor and connected to the liquid feed pipe.

[0011] The flow guide plate is installed on the inner wall of the housing.

[0012] An air outlet is located at the top of the housing.

[0013] A gas-liquid separator located at the top of the gas-liquid mixing reactor, near the gas outlet, and a liquid outlet located in the middle of the shell, and

[0014] The circulating liquid inlet is located at the top of the housing;

[0015] The gas-liquid mixing reactor does not include a mechanical stirring device.

[0016] The gas-liquid mixing reactor of the present invention eliminates mechanical stirring. The raw materials CO and methanol enter the reactor at a certain angle under the action of a gas distributor, a liquid injection pipe or a liquid distributor and a guide plate, which drives the liquid in the reactor to rotate. During the rotation, gas-liquid reaction occurs continuously, which is conducive to the full mixing of gas and liquid, thereby improving reaction efficiency and conversion rate.

[0017] In this invention, the liquid injection pipe or liquid distributor can be located above or below the gas distributor.

[0018] In one or more embodiments, the gas-liquid mixing reactor further includes a liquid stabilizing plate located above the gas-liquid mixing reactor and disposed below the gas-liquid separator.

[0019] In one or more embodiments, the liquid stabilizer plate has a length and width of 200mm × 150mm.

[0020] In one or more embodiments, the gas-liquid mixing reactor includes 3-10 sets of liquid stabilizing plates, each set of liquid stabilizing plates consisting of three liquid stabilizing plates.

[0021] This invention incorporates a liquid-stabilizing plate at the top of the gas-liquid mixing reactor. This stabilizes the liquid level, increases the effective liquid level height, increases the reaction volume, and improves the reaction yield, thereby enhancing output for large-scale industrial applications. Using three liquid-stabilizing plates to form a liquid-stabilizing plate assembly and setting up 3-10 sets of such assemblies further facilitates better liquid level stabilization.

[0022] In one or more embodiments, the gas distributor is an annular tubular gas distributor.

[0023] In one or more embodiments, the gas distributor has gas nozzles distributed on it.

[0024] In one or more embodiments, the gas nozzle is a conical gas nozzle.

[0025] In one or more embodiments, the top and bottom diameters of the conical gas nozzle are 0.2 mm to 20 mm.

[0026] In one or more embodiments, the top diameter of the conical gas nozzle is smaller than the bottom diameter.

[0027] In one or more embodiments, the top diameter of the conical gas nozzle is 1 mm to 3.5 mm, and the bottom diameter of the conical gas nozzle is 3 mm to 5.5 mm.

[0028] In one or more embodiments, the angle between the liquid injection pipe and the horizontal plane is 40° to 45°.

[0029] In one or more embodiments, the liquid distributor includes an annular tube and a liquid nozzle connected to the annular tube, the liquid nozzle having an angle of 40° to 45° with respect to the horizontal plane.

[0030] In one or more embodiments, the liquid injection pipe is a tapered liquid injection pipe, and the end diameter of the tapered liquid injection pipe is 5% to 50% of the pipe diameter.

[0031] In one or more embodiments, the liquid nozzle is a conical liquid nozzle, and the end diameter of the conical liquid nozzle is 5% to 50% of the pipe diameter.

[0032] In one or more embodiments, the number of liquid nozzles per square meter of gas-liquid mixing reactor cross-section is 4 to 10.

[0033] This invention designs a gas distributor and a liquid injection pipe or liquid distributor to ensure that the raw materials CO and methanol enter the reactor at a certain angle under the action of the gas distributor, liquid injection pipe or liquid distributor and guide plate, which promotes the rotation of the liquid in the reactor and facilitates the full mixing of gas and liquid.

[0034] In one or more embodiments, the deflector is a finned arc-shaped deflector.

[0035] In one or more embodiments, the width of the deflector is 100mm to 500mm and the length is 200mm to 1000mm.

[0036] In one or more embodiments, the guide plate has sieve holes.

[0037] In one or more embodiments, the number of the deflector plates is 5 to 50.

[0038] This invention uses a finned guide plate with sieve holes. The sieve holes can balance the pressure on both sides of the guide plate, break up large bubbles in the rotating reaction liquid, and guide the liquid, which helps to increase the gas-liquid contact area and improve reaction efficiency and conversion rate.

[0039] Another aspect of the invention provides a method for synthesizing acetic acid using a gas-liquid mixing reactor as described in any embodiment herein, the method comprising the steps of:

[0040] (1) The mixture is fed into the liquid feed pipe and then into the gas-liquid mixing reactor via the liquid injection pipe or the liquid distributor. CO gas is fed into the gas feed pipe and then into the gas-liquid mixing reactor via the gas distributor, so that the mixture and CO react in the gas-liquid mixing reactor to obtain a reaction solution containing acetic acid.

[0041] (2) The reaction solution is purified into acetic acid;

[0042] The mixture comprises mother liquor, methanol, dilute acid and iodomethane, wherein the mother liquor is a catalyst-containing liquid obtained by flash evaporation of the reaction solution.

[0043] In one or more embodiments, the method includes: purifying a portion of the reaction solution and returning another portion of the reaction solution to the gas-liquid mixing reactor after cooling through the circulating liquid inlet; preferably, the mass ratio of the purified reaction solution to the reaction solution returned to the gas-liquid mixing reactor is 1:(1-5), more preferably 1:(1-3).

[0044] In one or more embodiments, the reaction temperature is 180°C to 250°C, preferably 190°C to 230°C.

[0045] In one or more embodiments, the reaction pressure is 2.6 MPaG to 3.5 MPaG, preferably 2.7 MPaG to 3.3 MPaG.

[0046] In one or more embodiments, the CO gas enters the gas-liquid mixing reactor at a flow rate of 30 m / s to 50 m / s.

[0047] In one or more embodiments, the flow rate of the mixture entering the gas-liquid mixing reactor is 2 m / s to 6 m / s.

[0048] In one or more embodiments, the maximum temperature difference within the gas-liquid mixing reactor is ≤5°C.

[0049] Using the gas-liquid mixing reactor of the present invention to prepare acetic acid, and employing the reaction conditions described above, the maximum temperature difference within the reactor can be controlled below 5°C, making the reaction process more stable and improving the purity of the product and the reaction rate.

[0050] Another aspect of the present invention provides a production system for use in the synthesis of acetic acid, comprising:

[0051] The gas-liquid mixing reactor described in any of the embodiments herein

[0052] A flash evaporator connected to the outlet of the gas-liquid mixing reactor.

[0053] The light component removal tower is connected to the outlet of the flash evaporator.

[0054] A drying tower connected to the outlet of the light component removal tower,

[0055] The debinding and recombining column is connected to the outlet of the drying column.

[0056] A first pipe connecting the outlet of the gas-liquid mixing reactor to the circulating liquid inlet of the gas-liquid mixing reactor, and

[0057] A second pipe connecting the liquid outlet of the flash evaporator to the liquid feed pipe of the gas-liquid mixing reactor.

[0058] In one or more embodiments, the light component removal tower and the drying tower are combined into a light component removal-drying combined tower; in this case, the production system that can be used for acetic acid synthesis includes:

[0059] The gas-liquid mixing reactor described in any of the embodiments herein

[0060] A flash evaporator connected to the outlet of the gas-liquid mixing reactor.

[0061] The light component removal-drying combined tower is connected to the outlet of the flash evaporator.

[0062] The heavy component removal tower is connected to the outlet of the light component removal-drying combined tower.

[0063] A first pipe connecting the outlet of the gas-liquid mixing reactor to the circulating liquid inlet of the gas-liquid mixing reactor, and

[0064] A second pipe connecting the liquid outlet of the flash evaporator to the liquid feed pipe of the gas-liquid mixing reactor.

[0065] The acetic acid synthesis system used in this invention has a simple structure. By employing the aforementioned gas-liquid mixing reactor, the product conversion rate is improved, subsequent processing is simplified, production costs are reduced, and it is suitable for industrial applications.

[0066] In one or more embodiments, the production system further includes a catalyst trap disposed between the flash evaporator and the light component removal tower.

[0067] In one or more embodiments, the production system further includes a catalyst trap disposed between the flash evaporator and the light component removal-drying combined tower.

[0068] In one or more embodiments, the production system further includes a heat exchanger disposed on the first pipeline.

[0069] In this invention, the heat exchanger functions as follows: the reaction generates heat, causing the reaction system to heat up; a stream of reaction liquid is drawn from the reactor and circulated to the heat exchanger, removing the heat of reaction; the cooled reaction liquid returns to the reactor through the circulating liquid inlet at the top of the reactor, also driving the liquid inside the reactor to rotate, improving reaction efficiency and conversion rate. The catalyst collector recovers the catalyst, processing and reusing it to reduce catalyst costs; furthermore, pre-recovering the catalyst simplifies the subsequent product processing flow and reduces the burden on the equipment.

[0070] Another aspect of the invention provides a method for synthesizing acetic acid using a production system described in any embodiment herein, the method comprising preparing a reaction solution containing acetic acid using the gas-liquid mixing reactor, and then purifying the reaction solution into acetic acid using the flash evaporator, the catalyst trap, the light component removal tower, and the heavy component removal tower. Attached Figure Description

[0071] Figure 1 This is a schematic diagram of a gas-liquid mixing reactor in some embodiments of the present invention.

[0072] Figure 2 This is a schematic diagram of a gas-liquid mixing reactor in some embodiments of the present invention.

[0073] Figure 3 This is a schematic diagram of a liquid stabilizing plate assembly in some embodiments of the present invention.

[0074] Figure 4 This is a schematic diagram of the gas nozzle on the gas distributor in some embodiments of the present invention.

[0075] Figure 5 This is a schematic diagram of a liquid distributor in some embodiments of the present invention.

[0076] Figure 6 This is a schematic diagram of an acetic acid production system in some embodiments of the present invention.

[0077] Figure 7 This is a schematic diagram of an acetic acid production system in some embodiments of the present invention.

[0078] The annotations in the attached figures are explained as follows:

[0079] 1 is the gas feed pipe, 2 is the liquid feed pipe, 3 is the guide plate, 4 is the circulating liquid inlet, 5 is the gas-liquid separator, 6 is the liquid outlet, 7 is the gas outlet, 8 is the gas distributor, 9 is the liquid distributor, 10 is the liquid stabilizing plate, a, b, c, d, e, and f are the dimensions and spacing parameters of the liquid stabilizing plate assembly, a1 and b1 are the top and bottom orifice diameters of the nozzles on the gas distributor, a2 and b2 are the end diameter and pipe diameter of the conical liquid nozzles on the liquid distributor, α is the angle between the conical liquid nozzles and the horizontal plane, 11 is the gas-liquid mixing reactor, 12 is the flash evaporator, 13 is the light component removal-drying combined tower, 14 is the heavy component removal tower, 15 is the heat exchanger, 16 is the catalyst trap, 17 is the light component removal tower, and 18 is the drying tower. Detailed Implementation

[0080] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used herein are explained and defined in general terms below. Unless otherwise specified, all technical and scientific terms used herein have the common meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0081] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0082] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0083] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0084] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0085] In this article, the sum of the percentages of all components in the composition is 100%.

[0086] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope of this invention.

[0087] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0088] In some implementation schemes, such as Figure 1 As shown, the gas-liquid mixing reactor of the present invention, which can be used for the synthesis of acetic acid from methanol carbonylation, includes: a shell, a gas feed pipe 1, a gas distributor 8, a liquid feed pipe 2, a liquid distributor 9, a gas outlet 7, a liquid outlet 6, a gas-liquid separator 5, a guide plate 3, and a circulating liquid inlet 4.

[0089] In this invention, a mixture of mother liquor, methanol, dilute acid, and iodomethane is introduced into the liquid feed pipe. The mass fractions of the mother liquor, methanol, dilute acid, and iodomethane in the mixture can be 30%–80%, 5%–30%, 5%–30%, and 5%–30%, respectively. The mother liquor contains acetic acid, water, lithium salt, rhodium complex, and iodine compound. The mass fractions of acetic acid, water, lithium salt (calculated as lithium), rhodium complex (calculated as rhodium), and iodine compound (calculated as iodine) in the mother liquor can be 70%–90%, 3%–10%, 2000ppm–20000ppm, 300ppm–3000ppm, and 5%–35%, respectively. The dilute acid may contain acetic acid and water, and optionally may also contain iodomethane and methyl acetate. In the dilute acid, the mass fractions of acetic acid, water, iodomethane, and methyl acetate can be 30%–60%, 30%–70%, 0%–15%, and 0%–5%, respectively. In this invention, the lithium salt can be one or both selected from lithium iodide and lithium acetate. In this invention, the rhodium complex can be one or more selected from diiododicarbonyl rhodium, triiododicarbonyl rhodium, tetraiododicarbonyl rhodium, pentaiodocarbonyl rhodium, and rhodium acetate. In this invention, the iodine compound can be one or more selected from iodomethane, hydrogen iodide, and iodoethane.

[0090] The gas-liquid separator applicable to this invention can be a demister.

[0091] The interior of the casing is equipped with baffles at intervals.

[0092] The gas-liquid mixing reactor of the present invention preferably includes a stabilizing plate. Because the rotating liquid inside the reactor forms vortices at the top surface, causing the liquid level to appear lower in the middle and higher around the edges, this reduces the actual volume of the reaction liquid or results in false liquid levels, thus reducing the throughput. Adding a stabilizing plate makes the liquid level at the top of the reactor more stable, increasing the effective reaction volume and thus increasing the throughput.

[0093] In some preferred embodiments, such as Figure 2As shown, a liquid stabilizing plate 10 can be installed at the lower end of the gas-liquid separator 5 on the upper part of the gas-liquid mixing reactor. The length and width of the liquid stabilizing plate can be 200mm × 150mm. Depending on the diameter of the gas-liquid mixing reactor, 3-10 sets of liquid stabilizing plates can be designed, with each set consisting of 3 liquid stabilizing plates.

[0094] In some preferred embodiments, such as Figure 3 As shown, three liquid-stabilizing plates are combined into one liquid-stabilizing plate assembly. One end of each liquid-stabilizing plate is welded to the inner wall of the shell, and the other end extends towards the center of the gas-liquid mixing reactor. The three liquid-stabilizing plates can be arranged as follows: Figure 3 The arrangement shown is triangular, but it can also be arranged in a straight line diagonally upwards. Figure 3 Taking the triangular arrangement as an example, the preferred dimensions and spacing parameters of the liquid stabilizing plate assembly are: a = 300mm~900mm, b = 150mm~450mm, c = 300mm~900mm, d = 150mm~450mm, e = 50mm~300mm, and f = 50mm~500mm.

[0095] The gas distributor has several gas nozzles distributed on it. In some embodiments, the gas distributor includes an annular tube with tapered gas nozzles. For example... Figure 4 As shown, the top diameter of the conical gas nozzle is a1, and the bottom diameter is b1. The top diameter a1 and bottom diameter b1 of the conical gas nozzle can range from 0.2 mm to 20 mm, with b1 typically larger than a1. In some embodiments, a1 is Ф1 mm and b1 is Ф3 mm; or a1 is Ф1.5 mm and b1 is Ф3.5 mm; or a1 is Ф2 mm and b1 is Ф4 mm; or a1 is Ф2.5 mm and b1 is Ф4.5 mm; or a1 is Ф3 mm and b1 is Ф5 mm; or a1 is Ф3.5 mm and b1 is Ф5.5 mm. As the gas passes through the conical orifice, the flow velocity increases, typically reaching 30 m / s to 50 m / s. After being ejected from the orifice, the gas enters the liquid as small-diameter bubbles, which facilitates gas diffusion into the liquid and accelerates the carbonylation reaction. In this invention, a gas distributor and a liquid distributor are used together.

[0096] In some embodiments, the liquid distributor includes an annular tube and a liquid nozzle communicating with the annular tube. In some embodiments, such as Figure 5 As shown, the liquid nozzle is a conical nozzle, and the angle between the liquid nozzle and the horizontal plane is α, preferably 40° to 45°. The diameter b2 at the end of the conical nozzle is preferably 5% to 50% of the pipe diameter a2. After passing through the liquid nozzle, the liquid velocity increases to 2 m / s to 6 m / s. After passing through the liquid distributor, the liquid is injected into the gas-liquid mixing reactor. Under the action of the injection angle, the injected mixture drives the liquid in the gas-liquid mixing reactor to rotate.

[0097] The guide plate can be a finned arc-shaped plate with a width of 100-500 mm and a length of 200-1000 mm. The guide plate has perforated sieves, which balance the pressure on both sides of the guide plate and break up large air bubbles in the rotating reaction liquid, achieving better mixing of the gas and liquid phases. This invention eliminates the need for traditional mechanical stirring devices, thus eliminating leakage problems.

[0098] Gas-liquid separators can be demisters, such as wire mesh demisters, high-efficiency blade demisters, and filters. The materials used in gas-liquid separators can include zirconium wire, glass fiber, ceramic fiber, and PTFE mesh. The function of a gas-liquid separator is to reduce the amount of reaction liquid carried over from the reaction tail gas to subsequent processes.

[0099] The generation system of the present invention, which can be used to synthesize acetic acid from methanol carbonylation, includes the gas-liquid mixing reactor, flash evaporator, light component removal tower, and heavy component removal tower of the present invention.

[0100] The raw material CO enters the lower part of the gas-liquid mixing reactor through a gas feed pipe and a gas distributor. A mixture of mother liquor, dilute acid, iodomethane, methanol, and rich methanol (rich in iodomethane) absorbed from the tail gas enters the lower part of the gas-liquid mixing reactor through a liquid feed pipe and a liquid distributor. The gas and liquid distributors are evenly distributed. Driven by the liquid, CO rotates and rises within the reactor, initiating the carbonylation reaction.

[0101] The reaction liquid after the reaction is collected from the outlet. In a preferred embodiment, a portion of the reaction liquid is circulated outside the reactor to remove the heat of reaction, while the other portion enters a flash evaporator for flash evaporation. The mass ratio of the purified reaction liquid to the reaction liquid returned to the gas-liquid mixing reactor is preferably 1:(1-5), more preferably 1:(1-3).

[0102] In the flash evaporator, acetic acid and light components are vaporized and enter the light component removal tower. Preferably, a catalyst trap is installed between the flash evaporator and the light component removal tower. The catalyst trap collects the catalyst and returns it to the bottom of the flash evaporator. The liquid phase in the flash evaporator, i.e., the mother liquor, is returned to the gas-liquid mixing reactor to continue participating in the reaction. The gas phase from the flash evaporator or catalyst trap enters the light component removal tower to remove water, methyl acetate, iodomethane, methyl acetate, and other light component impurities. Crude acetic acid is drawn from the bottom of the light component removal tower and enters the heavy component removal tower for further removal of propionic acid and salts. Qualified acetic acid is collected from the top of the heavy component removal tower or from the top side stream.

[0103] In a preferred embodiment, a heat exchanger can also be installed between the gas-liquid mixing reactor and the flash evaporator. The working process of the heat exchanger is as follows: the reaction generates heat and the temperature rises. A stream of reaction liquid is drawn from the upper part of the reactor and circulated into the heat exchanger to remove the heat of reaction. The cooled reaction liquid returns to the reactor from the circulating liquid inlet at the top of the reactor, which has the functions of removing heat and stirring the liquid. The returning reaction liquid also has a certain directional velocity, which can drive the liquid in the reactor to rotate.

[0104] In a preferred embodiment, a drying tower is provided between the light component removal tower and the heavy component removal tower. The main function of the light component removal tower is to remove iodomethane, methyl acetate, and water. However, water and iodomethane are difficult to remove completely, so it is preferable to provide a drying tower to further remove water and iodomethane. The light component removal tower and the drying tower can be combined into a light component removal-drying combined tower, so this objective can be achieved using only the light component removal-drying combined tower.

[0105] In some implementation schemes, such as Figure 6 As shown, the production system of the present invention for acetic acid synthesis includes: a gas-liquid mixing reactor 11, a flash evaporator 12 connected to the liquid outlet of the gas-liquid mixing reactor 11, a catalyst trap 16 connected to the gas outlet of the flash evaporator 12, a light component removal-drying combined tower 13 connected to the catalyst trap 16, a heavy component removal tower 14 connected to the liquid outlet of the light component removal-drying combined tower 13, a first pipe connecting the liquid outlet of the gas-liquid mixing reactor 11 to the circulating liquid inlet of the gas-liquid mixing reactor 11, a second pipe connecting the liquid outlet of the flash evaporator 12 to the liquid feed pipe of the gas-liquid mixing reactor 11, and a heat exchanger 15 disposed on the first pipe.

[0106] In some implementation schemes, such as Figure 7 As shown, the production system of the present invention for acetic acid synthesis includes: a gas-liquid mixing reactor 11, a flash evaporator 12 connected to the liquid outlet of the gas-liquid mixing reactor 11, a light component removal tower 17 connected to the gas outlet of the flash evaporator 12, a drying tower 18 connected to the liquid outlet of the light component removal tower 17, a heavy component removal tower 14 connected to the liquid outlet of the drying tower, a first pipe connecting the liquid outlet of the gas-liquid mixing reactor 11 to the circulating liquid inlet of the gas-liquid mixing reactor 11, a second pipe connecting the liquid outlet of the flash evaporator 12 to the liquid feed pipe of the gas-liquid mixing reactor 11, and a heat exchanger 15 disposed on the first pipe.

[0107] The present invention has the following beneficial effects:

[0108] 1. The gas-liquid mixing reactor of this invention eliminates the need for a mechanical stirring device. Raw materials CO and methanol enter the reactor at a specific angle under the action of a gas distributor, a liquid distributor, and a guide plate, driving the liquid inside the reactor to rotate. During this rotation, continuous gas-liquid reactions occur, promoting thorough mixing. As the gas and liquid rise, bubbles are broken up on the perforated guide plate, and the liquid is guided, forming finer bubbles, which increases the gas-liquid contact area, improving reaction efficiency and conversion rate. This invention effectively reduces the temperature difference between the top and bottom of the reactor. The temperature difference in ordinary reactors without stirring is 5-15℃, while in reactors with mechanical stirring devices it is generally 3-10℃. The gas-liquid mixing reactor of this invention can achieve a temperature difference of less than 5℃, making the reaction process more stable and improving product purity and reaction rate.

[0109] 2. The gas-liquid mixing reactor of the present invention is equipped with a gas-liquid separator at the gas outlet to prevent the gas phase from entraining reaction droplets. The liquid contains the catalyst rhodium or iridium. When the gas phase entrains droplets, the catalyst will enter the condenser. After separation by the condenser, the catalyst will continue to return to the reactor. Some catalyst will precipitate in the pipeline. However, if the gas phase entrains a large amount of reaction droplets, the separator may not be able to return the catalyst to the reactor in time, and the catalyst will enter the distillation system, which may result in catalyst loss in severe cases.

[0110] 3. The gas-liquid mixing reactor of the present invention is preferably provided with a liquid stabilizing plate at the top to stabilize the liquid level, increase the effective liquid level height, and increase the reaction volume, so as to improve the output of large-scale industrial applications.

[0111] 4. This invention eliminates the need for a traditional mechanical stirrer, reducing the problem of leaks that can affect the operating cycle during mechanical stirring. This invention employs gas-hydraulic stirring without mechanical agitation, resulting in a static seal on the reactor and greater equipment stability under the reaction pressure.

[0112] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. The methods, reagents, and materials used in the embodiments and comparative examples are conventional methods, reagents, and materials in the art, unless otherwise stated. The starting material compounds in the embodiments and comparative examples are all commercially available.

[0113] Example 1

[0114] This embodiment adopts Figure 2 The gas-liquid mixing reactor shown Figure 6The production system shown synthesizes acetic acid. The conical gas nozzles of the gas distributor have the following orifice diameters: a1 is Ф1mm, b1 is Ф3mm; the liquid distributor nozzles are conical, with nozzle diameter a2 being DN50 (nominal diameter 50mm), and the diameter of the conical nozzle tip b2 being 20mm. The angle α between the conical nozzle and the horizontal plane is 45°; the liquid stabilizing plates are 200mm × 150mm in length and width, using three sets of liquid stabilizing plates, each set consisting of three liquid stabilizing plates, as shown... Figure 3 As shown, three liquid-stabilizing plates are combined into one liquid-stabilizing plate assembly. One end of each plate is welded to the inner wall of the shell, and the other end extends towards the center of the gas-liquid mixing reactor. The three plates are arranged in a triangular pattern. Twelve guide plates are evenly distributed inside the shell, each measuring 600mm x 300mm. The flow velocity of the mixed liquid injected into the reactor is 3m / s. The mixed liquid contains mother liquor, methanol, dilute acid, and iodomethane. The mass fractions of mother liquor, methanol, dilute acid (40wt% water + 60wt% acetic acid), and iodomethane in the mixed liquid are 65%, 10%, 10%, and 15%, respectively. The mother liquor contains acetic acid, water, and... The reactor consisted of lithium salt, rhodium complex, and iodine compound. Specifically, the lithium salt was lithium iodide, the rhodium complex was rhodium diiodocarbonyl, and the iodine compound was hydrogen iodide. The contents of acetic acid, water, lithium iodide (calculated as lithium), rhodium diiodocarbonyl (calculated as rhodium), and hydrogen iodide (calculated as iodine) were 85%, 3%, 8000 ppm, 1500 ppm, and 10%, respectively. The CO gas flow rate into the reactor was 35 m / s. The pressure inside the reactor was 3.0 MPaG. The temperature distribution inside the reactor is shown in Table 1. The mass ratio of the reaction liquid entering the flash evaporator to the portion entering the reactor as circulating liquid was 1:2. Three experiments were conducted. The yield of acetic acid is shown in Table 1. The specific consumption of rhodium catalyst was 0.02 g / t acetic acid.

[0115] Table 1: Reactor temperature and acetic acid yield in Example 1

[0116]

[0117] Example 2

[0118] This embodiment adopts Figure 2 The gas-liquid mixing reactor shown Figure 7 The production system shown synthesizes acetic acid. The conical gas nozzles of the gas distributor have the following diameters: a1 is Ф2.5mm, b1 is Ф4.5mm; the liquid distributor nozzles are conical, with nozzle diameter a2 being DN80 (nominal diameter 80mm), the ratio of the conical nozzle end diameter b2 to the nozzle diameter a2 is 1:3, and the angle α between the conical nozzle and the horizontal plane is 40°; the liquid stabilizing plates are 200mm × 150mm in length and width, using 5 sets of liquid stabilizing plates, each set consisting of three liquid stabilizing plates, as shown... Figure 3As shown, three liquid-stabilizing plates are combined into one liquid-stabilizing plate assembly. One end of each plate is welded to the inner wall of the shell, and the other end extends towards the center of the gas-liquid mixing reactor. The three plates are arranged in a triangular pattern. Twenty guide plates are evenly distributed inside the shell, each measuring 800mm × 400mm. The flow velocity of the mixed liquid injected into the reactor is 5m / s. The mixed liquid contains mother liquor, methanol, dilute acid, and iodomethane. The mass fractions of mother liquor, methanol, dilute acid (35wt% water + 65wt% acetic acid), and iodomethane in the mixed liquid are 55%, 15%, 10%, and 20%, respectively. The mother liquor contains acetic acid... The reactor contained acetic acid, water, lithium salt, rhodium complex, and iodine compound. Specifically, the lithium salt was lithium acetate, the rhodium complex was rhodium acetate, and the iodine compound was iodoethane. The contents of acetic acid, water, lithium acetate (calculated as lithium), rhodium acetate (calculated as rhodium), and iodoethane (calculated as iodine) were 88%, 2%, 10000 ppm, 1700 ppm, and 8%, respectively. The flow rate of CO gas injected into the reactor was 40 m / s. The pressure inside the reactor was 2.8 MPaG. The temperature distribution inside the reactor is shown in Table 2. The mass ratio of the reaction liquid entering the flash evaporator to the portion entering the reactor as circulating liquid was 1:2.5. Three experiments were conducted. The yield of acetic acid is shown in Table 2. The specific consumption of rhodium catalyst was 0.03 g / t acetic acid.

[0119] Table 2: Reactor temperature and acetic acid yield in Example 2

[0120]

[0121] Example 3

[0122] The only difference between Example 3 and Example 1 is that the liquid level stabilizer is not installed in the gas-liquid mixing reactor; all other conditions remain unchanged. The temperature distribution and acetic acid yield within the reactor are shown in Table 3. From the experimental results in Tables 1 and 3, it can be seen that installing the liquid level stabilizer in the reactor in Example 1 can stabilize the liquid level, increase the effective liquid level height, increase the reaction volume, and improve the reaction yield.

[0123] Table 3: Reactor temperature and acetic acid yield in Example 3

[0124]

[0125] Comparative Example 1

[0126] The only difference between Comparative Example 1 and Example 1 is that the angle α between the nozzle on the liquid distributor and the horizontal plane is 90°, while all other conditions remain unchanged. The temperature distribution and acetic acid yield in the reactor are shown in Table 4. In the reactor of Comparative Example 1, the liquid phase is sprayed vertically upwards and then comes into contact with the gas phase coming out from above. The gas-liquid mixture is uneven at the bottom. In contrast, in Example 1, the liquid distributor is equipped with nozzles with a 45° inclination angle, which agitates the liquid at the bottom, eliminating dead zones in the bottom temperature and resulting in a more uniform temperature. The gas-liquid mixing efficiency and uniformity are also better. Therefore, the reaction yield of Comparative Example 1 is lower than that of Example 1.

[0127] Table 4: Reactor temperature and acetic acid yield of Comparative Example 1

[0128]

[0129] Comparative Example 2

[0130] The only difference between Comparative Example 2 and Example 2 is that the nozzles on the gas distributor are holes with the same inner and outer diameters, i.e., a1 and b1 are both Ф4mm. All other conditions remain unchanged. The temperature distribution and acetic acid yield in the reactor are shown in Table 5. In Comparative Example 2, the kinetic energy of the gas phase entering the liquid phase in the reactor is insufficient, and even at low gas velocities, liquid may leak into the gas distributor. In Example 2, the gas has sufficient kinetic energy to enter the liquid under the action of the conical orifice, making leakage less likely and more conducive to gas distribution and mixing, resulting in a more uniform temperature. Therefore, the reaction yield of Comparative Example 2 is lower than that of Example 2.

[0131] Table 5: Reactor temperature and acetic acid yield of Comparative Example 1

[0132]

Claims

1. A gas-liquid mixing reactor, comprising: case, The gas feed pipe and liquid feed pipe pass through the lower part of the housing. A gas distributor located at the bottom of the gas-liquid mixing reactor and connected to the gas feed pipe. A liquid injection pipe or liquid distributor located at the bottom of the gas-liquid mixing reactor and connected to the liquid feed pipe. The flow guide plate is installed on the inner wall of the housing. An air outlet is located at the top of the housing. The gas-liquid separator is located at the top of the gas-liquid mixing reactor, near the gas outlet. The liquid outlet is located in the middle of the housing, and The circulating liquid inlet is located at the top of the housing; The gas-liquid mixing reactor does not include a mechanical stirring device; The gas-liquid mixing reactor also includes a liquid stabilizing plate located above the gas-liquid mixing reactor and below the gas-liquid separator.

2. The gas-liquid mixing reactor as described in claim 1, characterized in that, The liquid stabilizing plate has a length and width of 200mm × 150mm.

3. The gas-liquid mixing reactor as described in claim 1, characterized in that, The gas-liquid mixing reactor includes 3-10 sets of liquid stabilizing plates, and each set of liquid stabilizing plates consists of three liquid stabilizing plates.

4. The gas-liquid mixing reactor as described in claim 1, characterized in that, The gas distributor is a ring-shaped tubular gas distributor; and / or The gas distributor has gas nozzles distributed on it.

5. The gas-liquid mixing reactor as described in claim 4, characterized in that, The gas nozzle is a conical gas nozzle.

6. The gas-liquid mixing reactor as described in claim 5, characterized in that, The top and bottom diameters of the conical gas nozzle are 0.2 mm to 20 mm, with the top diameter being smaller than the bottom diameter.

7. The gas-liquid mixing reactor as described in claim 5, characterized in that, The top diameter of the conical gas nozzle is 1mm to 3.5mm, and the bottom diameter of the conical gas nozzle is 3mm to 5.5mm.

8. The gas-liquid mixing reactor as described in claim 1, characterized in that, The angle between the liquid injection pipe and the horizontal plane is 40°~45°, or the liquid distributor includes an annular pipe and a liquid nozzle connected to the annular pipe, wherein the angle between the liquid nozzle and the horizontal plane is 40°~45°.

9. The gas-liquid mixing reactor as described in claim 1, characterized in that, The liquid injection pipe is a tapered liquid injection pipe, and the end diameter of the tapered liquid injection pipe is 5% to 50% of the pipe diameter.

10. The gas-liquid mixing reactor as described in claim 8, characterized in that, The liquid nozzle is a conical liquid nozzle, and the end diameter of the conical liquid nozzle is 5% to 50% of the pipe diameter.

11. The gas-liquid mixing reactor as described in claim 8, characterized in that, The number of liquid nozzles per square meter of the gas-liquid mixing reactor cross-section is 4 to 10.

12. The gas-liquid mixing reactor as described in claim 1, characterized in that, The deflector plate has one or more of the following features: The guide vane is a finned arc-shaped guide vane; The width of the guide plate is 100mm~500mm and the length is 200mm~1000mm; The guide plate has sieve holes; The number of the guide vanes is 5-50.

13. A method for synthesizing acetic acid using a gas-liquid mixing reactor according to any one of claims 1-12, characterized in that, The method includes the following steps: (1) The mixture is fed into the liquid feed pipe, and then into the gas-liquid mixing reactor via the liquid injection pipe or the liquid distributor. CO gas is fed into the gas feed pipe and then into the gas-liquid mixing reactor via the gas distributor, so that the mixture and CO react in the gas-liquid mixing reactor to obtain a reaction solution containing acetic acid. (2) The reaction solution is purified into acetic acid; The mixture comprises mother liquor, methanol, dilute acid and iodomethane, wherein the mother liquor is a catalyst-containing liquid obtained by flash evaporation of the reaction solution.

14. The method as described in claim 13, characterized in that, The method has one or more of the following characteristics: The method includes: purifying a portion of the reaction solution, and returning another portion of the reaction solution to the gas-liquid mixing reactor through the circulating liquid inlet after cooling. The reaction temperature is 180℃~250℃; The reaction pressure is 2.6 MPaG to 3.5 MPaG; The flow rate of CO gas entering the gas-liquid mixing reactor is 30 m / s to 50 m / s; The flow rate of the mixture entering the gas-liquid mixing reactor is 2 m / s to 6 m / s; The maximum temperature difference within the gas-liquid mixing reactor is ≤5℃.

15. The method as described in claim 14, characterized in that, The mass ratio of the purified reaction liquid to the reaction liquid returned to the gas-liquid mixing reactor is 1:(1~5).

16. The method as described in claim 14, characterized in that, The mass ratio of the purified reaction liquid to the reaction liquid returned to the gas-liquid mixing reactor is 1:(1~3).

17. The method as described in claim 14, characterized in that, The reaction temperature is 190℃~230℃.

18. The method as described in claim 14, characterized in that, The reaction pressure is 2.7 MPaG to 3.3 MPaG.

19. A production system for the synthesis of acetic acid, comprising: The gas-liquid mixing reactor according to any one of claims 1-12, A flash evaporator connected to the outlet of the gas-liquid mixing reactor. The light component removal tower is connected to the outlet of the flash evaporator. A drying tower connected to the outlet of the light component removal tower, The debinding and recombining column is connected to the outlet of the drying column. A first pipe connecting the outlet of the gas-liquid mixing reactor to the circulating liquid inlet of the gas-liquid mixing reactor, and A second pipe connecting the liquid outlet of the flash evaporator to the liquid feed pipe of the gas-liquid mixing reactor; The light component removal tower and the drying tower can be combined into a light component removal-drying combined tower.

20. The production system as described in claim 19, characterized in that, The production system also includes: A catalyst trap is installed between the flash evaporator and the light component removal tower, and / or A heat exchanger installed on the first pipe.

21. A method for synthesizing acetic acid using the production system of claim 20, characterized in that, The method includes preparing a reaction solution containing acetic acid using the gas-liquid mixing reactor, and then purifying the reaction solution into acetic acid using the flash evaporator, the catalyst trap, the light component removal tower, and the heavy component removal tower.

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