A tubular reactor and its use in the synthesis of carbonyl metals

Abstract

This invention discloses a tubular reactor and its application in the synthesis of carbonyl metals, belonging to the field of chemical technology. It addresses the shortcomings of existing gas-liquid-solid three-phase reactions, which suffer from uneven gas dispersion, the formation of reaction dead zones, and insufficient gas supply to meet the gradual gas consumption during the reaction, leading to low reaction efficiency and unstable product yields. Furthermore, existing methods for synthesizing cobalt carbonyl often suffer from harsh reaction conditions, complex operations, difficulties in product separation, or the inability to achieve continuous and stable operation. This invention aims to provide a reactor, reaction system, and cobalt carbonyl synthesis method that can achieve uniform gas dispersion, match gas consumption requirements, and enable continuous production, thereby overcoming the aforementioned technical deficiencies.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, specifically a tubular reactor and its application in the synthesis of carbonyl metals. Background Technology

[0002] Cobalt carbonyl (or cobalt octacarbonyl, chemical formula Co₂(CO)₈) is a typical zero-valent transition metal carbonyl compound, an orange-yellow or reddish-brown solid at room temperature, exhibiting volatility and high reactivity. In its molecule, the cobalt atom is in a low valence state, forming a stable coordination structure with carbon monoxide. Under heating or reaction conditions, carbonyl dissociation or metal center transfer can occur. Due to these properties, cobalt carbonyl has significant applications in organometallic chemistry and industrial catalysis, particularly as a cobalt source widely used in carbonylation, hydroformylation, and related catalytic systems. It is also used as an important intermediate in scientific research and the preparation of specialty materials.

[0003] In existing technologies, the methods for preparing cobalt carbonyl mainly include the following categories: Direct carbonylation of metallic cobalt: This method uses metallic cobalt powder or sponge cobalt as raw materials, and reacts them in a carbon monoxide atmosphere under high temperature and pressure conditions to produce cobalt carbonyl. This method typically requires a high partial pressure of carbon monoxide and places high demands on the surface area and activity of the raw material metallic cobalt.

[0004] Cobalt oxide or cobalt hydroxide carbonylation: This method uses cobalt oxide or cobalt hydroxide as the cobalt source, introduces carbon monoxide into an organic solvent system, and uses hydrogen as a reducing gas. The cobalt source is reduced and undergoes a carbonylation reaction during the reaction to produce cobalt carbonyl. This route has attracted attention due to the readily available raw materials and relatively mild reaction pathway.

[0005] Salt or coordination compound conversion method: Some methods use cobalt salts or their coordination compounds as starting materials to generate cobalt carbonyl through reduction and carbonylation steps, but these methods often involve many steps and complex post-processing.

[0006] The method described above, which uses cobalt hydroxide (Co(OH)₂) as the cobalt source and involves introducing carbon monoxide into an organic solvent while supplementing with hydrogen gas, is considered a promising route for the synthesis of cobalt carbonyl (see patent US2476263A). In this reaction system, hydrogen gas mainly acts as a reducing agent, causing the cobalt center to change from a higher valence state to a lower valence state, subsequently coordinating with carbon monoxide to form cobalt carbonyl. This type of reaction is usually carried out in a closed reactor, with a gas phase (CO, H₂), a liquid phase (organic solvent), and a solid phase (cobalt hydroxide) present simultaneously. It is a typical gas-liquid-solid three-phase reaction system, and the required pressure is usually as high as 8 MPa. The reaction operation is complex and continuous reaction cannot be achieved. Summary of the Invention

[0007] To address the shortcomings of existing gas-liquid-solid three-phase reactions, such as uneven gas dispersion, the formation of reaction dead zones, and the inability of gas supply to match the gradual consumption of gas during the reaction, which leads to low reaction efficiency and unstable product yield, and the fact that existing methods for synthesizing cobalt carbonyl often suffer from harsh reaction conditions, complex operations, difficulties in product separation, or the inability to achieve continuous and stable operation, this invention aims to provide a reactor, reaction system, and cobalt carbonyl synthesis method that can achieve uniform gas dispersion, match gas consumption requirements, and enable continuous production, thereby overcoming the aforementioned technical deficiencies.

[0008] The objective of this invention can be achieved through the following technical solutions: This invention provides a tubular reactor, the core improvement of which lies in the integrated porous gas dispersion structure of the reactor wall. A preferred embodiment is as follows: Furthermore, the porous gas dispersion structure is arranged along the reactor axis at the front section of the reactor; Furthermore, the porous gas dispersion structure is configured as several segmented structures spaced apart from each other along the reactor axis, with each segmented porous structure separated by a solid wall section. The core purpose of the above segmented configuration is to achieve distributed gas entry along the reactor axis, so as to accurately match the gradual consumption of gas during the reaction process, avoid local gas excess or deficiency, and improve reaction uniformity and efficiency.

[0009] Furthermore, the gas supply and dispersion process of the reactor is as follows: The gas required for the reaction enters the gas supply chamber after flow regulation, forming a relatively uniform gas pressure distribution within the supply chamber. Under the radial pressure difference between the gas pressure in the supply chamber and the internal pressure of the reactor, the gas passes radially through the integrated porous gas dispersion structure of the reactor wall and enters the reaction zone inside the reactor. Since the porous gas dispersion structure has a three-dimensional interconnected pore network structure, the gas undergoes multiple micro-scale throttling and dispersion during its passage through the porous structure, thus entering the reaction system in a uniformly dispersed state, effectively avoiding gas agglomeration and improving the gas-liquid-solid three-phase contact efficiency.

[0010] Based on the tubular reactor with an integrated porous gas inlet structure, the present invention further provides a continuous reaction system, which can realize the continuous operation of gas-liquid-solid three-phase reaction, and includes the following components: 1. Feeding unit: used to continuously introduce liquid reaction medium and solid reactants, which are mixed to form a stable gas-liquid-solid reaction system, providing a stable feed for subsequent reactions; 2. Tubular reactor: The above-mentioned integrated porous gas inlet structure serves as the core site for the gas-liquid-solid three-phase reaction, used to complete the target reaction; 3. Solid-liquid separation unit: Located downstream of the tubular reactor, it is used to separate unreacted solid reactants or by-product solids generated during the reaction process in the reaction stream, so as to avoid solid impurities affecting the subsequent product separation; 4. Continuous crystallization or separation unit: Located downstream of the solid-liquid separation unit, it is used to process the liquid phase product after solid-liquid separation to achieve the separation and purification of the target product; 5. Mother liquor reflux unit: Used to return the mother liquor separated by the continuous crystallization or separation unit to the front end of the tubular reactor, mix it with the fresh feed, and participate in the reaction again, thereby improving the utilization rate of raw materials, reducing production costs, and realizing the stable operation of the reaction system.

[0011] Based on the above-described reactor and continuous reaction system, the present invention also provides a method for the continuous synthesis of cobalt carbonyl, which is simple to operate and can be run continuously and stably, and specifically includes the following steps: Step 1: Continuously introduce liquid reaction medium and solid reactants into the tubular reactor, and after thorough mixing, form a stable gas-liquid-solid reaction system; Step 2: The gas required for the reaction is introduced into the gas supply chamber after the flow rate is regulated. Under the radial pressure difference between the supply chamber and the inside of the reactor, the gas passes through the integrated porous gas dispersion structure of the reactor wall and enters the reaction zone inside the reactor in a uniformly dispersed state, so as to fully contact the gas-liquid-solid reaction system. Step 3: Under suitable reaction conditions in a tubular reactor, complete the gas-liquid-solid three-phase reaction to obtain a reaction stream containing cobalt carbonyl. Step 4: The above reaction streams are sequentially fed into the solid-liquid separation unit, continuous crystallization or separation unit to complete solid-liquid separation and target product separation, respectively. The separated mother liquor is returned to the front end of the tubular reactor through the mother liquor reflux unit, mixed with fresh feed and participated in the reaction again, so as to achieve continuous and stable operation of the entire synthesis process.

[0012] The beneficial effects of this invention are: 1. By setting a three-dimensional porous gas dispersion structure on the wall of the tubular reactor, compared with the existing gas inlet method that relies on jet dynamic pressure or local shear enhancement, the present invention improves the effective utilization efficiency of gas in the reaction system by changing the way gas enters the reactor, so that the reaction is no longer highly dependent on high gas partial pressure, thereby significantly reducing the minimum operating pressure required for the reaction and widening the pressure window for stable operation.

[0013] 2. In existing technologies, jet-type or point-inlet structures often lead to fluctuations in reaction rates, uneven gas distribution, and high sensitivity to changes in operating conditions, thus limiting the continuous and long-term operation of gas-liquid-solid three-phase reactions. This invention utilizes an integrated porous inlet structure on the vessel wall, allowing gas to continuously enter the reaction zone along the vessel wall in a surface-source manner, avoiding gas short-circuiting and localized gas shortages. Even under lower operating pressure conditions, a relatively uniform and stable gas phase distribution can be maintained throughout the entire reaction zone. Based on these structural improvements, the sensitivity of the reaction process to changes in gas flow rate, liquid phase state, and solid load is significantly reduced, effectively solving the process bottleneck problem of unstable continuous reaction operation under low-pressure conditions.

[0014] 3. Since the gas must pass through the porous wall to enter the reaction zone, all gases entering the reaction system undergo similar dispersion and mass transfer paths. This invention can effectively increase the effective residence time of carbon monoxide and hydrogen in the liquid phase and their participation in the reaction. Compared to schemes that enhance mixing by increasing shear strength or mechanical energy input, this invention mainly relies on structural design to achieve enhanced gas dispersion and mass transfer. While reducing operating pressure, it does not require a significant increase in additional energy consumption, thereby improving the gas utilization efficiency per unit product, reducing process fluctuations and operating energy consumption, and enhancing the engineering controllability and scale-up adaptability of continuous processes.

[0015] 4. Because the porous inlet structure is integrated with the reactor wall, the gas dispersion function is determined by the structure itself, without relying on complex built-in rotating components or high-shear parts, thus reducing equipment vibration, wear, and maintenance risks. Under continuous operation and scale-up conditions, this structure helps maintain the long-term stability of the internal flow field and gas distribution of the reactor. Simultaneously, the reaction can proceed at lower operating pressures, helping to reduce equipment pressure rating requirements and system risk levels, thereby improving the overall process safety, reliability, and industrial application value. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the cross-sectional structure of the tubular reactor in Example 2. a and a are, in order, the end view of the tube, the main body view of the tube, the longitudinal sectional view of the tube (AA), and the transverse sectional view of the tube (BB).

[0017] Figure 2 Schematic diagram of a continuous reaction process.

[0018] Figure 3 Infrared spectrum of cobalt carbonyl products. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] In their research on the synthesis of cobalt carbonyl using cobalt hydroxide (Co(OH)2) as the cobalt source in the presence of hydrogen and CO, the inventors discovered that significantly enhancing gas-liquid mixing (e.g., using a slip ring to introduce the fluid) can substantially reduce the reaction pressure. However, the slip ring structure has poor sealing performance, and its complex structure easily leads to solid deposition. Therefore, the inventors further designed an improved dynamic tubular reactor, achieving the same distribution effect under static conditions, avoiding the risk of dynamic seal leakage, and simultaneously offering the advantage of reducing reaction pressure. They also found that combining this with the application of nano-sized cobalt hydroxide (Co(OH)2) raw materials can further accelerate the reaction efficiency. Example 1:

[0021] This embodiment employs a dynamic tubular reactor with a high-pressure rotary joint (slip ring structure) to achieve the continuous synthesis of cobalt carbonyl. The reactor's central stirring shaft is hollow, with its top connected to an external gas supply pipeline via a high-pressure rotary joint. A mixed gas (CO / H2) enters the hollow shaft via the rotary joint and then enters the reaction zone through a microporous dispersion section (made of 316L stainless steel sintered porous material, with an equivalent pore size of 0.1 μm) installed in the axial middle section of the rotating shaft. Upon entering the reaction zone, the gas is directly subjected to centrifugal and shear forces generated by the high-speed rotation of the shaft, resulting in the mechanical breakup of the bubbles. Before the reaction begins, the system is purged with an inert gas to ensure an oxygen-free environment. A hexane solution of cobalt hydroxide is continuously introduced into the reactor.

[0022] The mass ratio of cobalt hydroxide to n-hexane is 1:19. In this embodiment, 2 wt% cobalt carbonyl is pre-dissolved in n-hexane as a catalyst to initiate the reaction. The inventors discovered that the reaction has autocatalytic properties; therefore, adding pre-dissolved cobalt carbonyl in n-hexane can accelerate the activation of cobalt hydroxide, so as to quickly establish a stable conversion rate in the continuous reaction process. The cobalt hydroxide must be thoroughly pulverized using a nano-pulverizer to a particle size of less than 6 μm and sieved through a 2000-mesh sieve to ensure good suspension in the solution. The n-hexane-cobalt hydroxide dispersion is delivered to the reactor at a hydraulic diaphragm pump at a rate of 120 g / min. Carbon monoxide and hydrogen are mixed at a molar ratio of 5:1 and fed into the hollow shaft through a rotary joint at a pressure of 3.5 MPa.

[0023] Rotary shaft speed: 1200 rpm; Reactor internal pressure: 3 MPa; Reaction temperature: 120°C oC; Reaction residence time: 5 min. Under the above conditions, the yield of cobalt carbonyl product was 10.84 g / min, the reaction conversion rate was 90.3%, and the selectivity was 98.2%. Yield calculation: Every 2 hours, the reaction liquid was collected and filtered, and 70 g of solid residue was collected. The aqueous phase of the reaction liquid was separated by a separator, and the filtrate was cooled to -40℃ for crystallization. After crystallization, it was filtered at low temperature, purged with nitrogen and dried, and the weight of the crystalline solid collected was 1254 g, which was cobalt carbonyl (its infrared spectrum is attached). Figure 3 The product, after titration, showed a cobalt content of 34.5 wt.% (purity ≥99.5%), and the filtrate weighed 12850 g. The filtrate was titrated, and the dissolved cobalt carbonyl content was determined to be 2.49 wt%.

[0024] The reaction conversion rate is calculated as follows: Reaction conversion rate = (1 - Filter solids / Cobalt hydroxide feed amount) × 100%, Wherein, the amount of cobalt hydroxide fed = the flow rate of the cobalt hydroxide dispersion × the cobalt hydroxide content × the reaction time; Output per unit time is calculated as follows: Output per unit time = Cobalt carbonyl output / time Wherein, cobalt carbonyl yield = weight of crystalline solids + weight of cobalt carbonyl dissolved in filtrate - weight of pre-dissolved cobalt carbonyl; Selectivity is calculated as follows: Selectivity = Cobalt carbonyl production / Theoretical Cobalt carbonyl production.

[0025] The calculation methods in the following embodiments all refer to the above formula.

[0026] Due to the strong shearing effect accompanying the rotary shaft air intake, the gas-liquid contact surface area is significantly increased, resulting in an extremely high reaction rate in the initial stage of the reaction, and a significantly shortened residence time required to achieve the same conversion rate. However, due to the stringent requirements for device sealing quality caused by high-pressure carbon monoxide (CO) and solid-containing systems, poor sealing and gas leakage were found after 20 hours of continuous operation. Therefore, the inventors further designed an improved tubular reactor. Example 2:

[0027] This embodiment employs an improved dynamic tubular reactor to achieve the continuous synthesis of cobalt carbonyl. The main difference between this improved tubular reactor and a conventional dynamic tubular reactor is that its gas inlet is directly located on the reactor wall at the front end. The front end structure is as follows: Figure 1As shown in the figure, the components are labeled as turbulence structure 1, heat exchange zone 2, three-dimensional porous structure zone 3, and gas supply chamber 4. In this embodiment, the three-dimensional porous structure layer 3 is made of sintered metal filter element structure, made of 316L stainless steel, with an equivalent pore size of 0.1μm and a thickness of 10mm. The three-dimensional porous structure layer 3 is arranged along the reactor axis at the front of the reactor, and its axial coverage length accounts for 85% of the effective reaction length of the reactor. During the reaction, the gas source is delivered to the gas supply chamber 4 through a conventional control unit (pressure reducing valve, flow meter, etc., not shown in the figure) to form a uniform gas pressure distribution, and then, under pressure, it permeates into the reaction zone inside the reactor through the three-dimensional porous structure layer 3. Except for the gas inlet being integrated with the reactor wall (i.e., the three-dimensional porous structure zone 3 and the gas supply chamber 4), other components can be designed with reference to the structure of conventional commercial dynamic tubular reactors.

[0028] In this embodiment, before the reaction begins, an inert gas is introduced into the reactor to purge air from the system. Then, hexane and Co(OH)₂ (prepared as a 5 wt% cobalt hydroxide suspension, referring to Example 1) are introduced into the reactor. Carbon monoxide and hydrogen are introduced into the gas supply chamber after flow rate control. The hexane solution is added at a rate of 120 g / min, the molar ratio of carbon monoxide to hydrogen is 5:1, and the carbon monoxide side pressure is 3.5 MPa. Under gas pressure, carbon monoxide and hydrogen radially penetrate the sintered metal porous gas dispersion structure and enter the reaction zone inside the reactor. The internal pressure of the reactor is 3 MPa, and the reaction temperature is 120°C. o C, reaction residence time 5 min. Through this radial pressure drop, the gas undergoes multiple microscale throttling and dispersion as it passes through the three-dimensional interconnected pore network inside the porous structure, thus entering the liquid phase inside the reactor in a uniformly dispersed form. It reacts with cobalt hydroxide in the liquid phase n-hexane to generate cobalt carbonyl product, with a conversion rate of 95% and a yield of 10.43 g / min.

[0029] Experiments have shown that the integrated wall design proposed in this embodiment achieves a distribution effect similar to that of slip ring intake under static conditions, while effectively avoiding the risk of sealing leakage in dynamic structures. Example 3:

[0030] This embodiment is based on the improved tubular reactor used in Example 2, and develops a continuous reaction separation process for cobalt carbonyl. The process is as follows: Figure 2 It includes, in sequence: a feeding unit for introducing feed A: Co(OH)2 and feed B: n-hexane; and a tubular reactor R1, the specific structure of which is as follows: Figure 1As shown; filtration unit F1; continuous cooling crystallizer R2; mother liquor reflux unit V1; receiving tank V2. The tubular reactor R1 is an integrally formed porous inlet reactor with a metal sintered porous gas dispersion structure partially installed on its wall. The outer side of this porous structure is connected to the gas supply pipeline of the mixed gas D, forming a gas supply chamber. This allows the mixed gas D to first form a uniform gas pressure distribution in the supply chamber before entering the reactor. The mixed gas D is a mixture of carbon monoxide and hydrogen, with a molar ratio of carbon monoxide to hydrogen of 5:1.

[0031] In the continuous reaction process, the reaction liquid C continuously enters the tubular reactor R1. The mixed gas D, after flow rate regulation, is introduced into the gas supply chamber outside the wall of the tubular reactor R1, forming a nearly uniform gas pressure field. Under the action of gas pressure, the mixed gas D radially passes through the integral metal sintered porous gas dispersion structure of the reactor wall and enters the internal reaction zone of the tubular reactor R1. A stable radial local pressure drop ΔP = 0.5 MPa is formed between the pressure outside the porous gas dispersion structure and the pressure inside the reactor. Through this radial local pressure drop, the mixed gas D undergoes multiple micro-scale throttling and dispersion as it passes through the three-dimensional interconnected pore network inside the porous structure, thus entering the reaction liquid C in a uniformly dispersed form. This allows the gas-liquid-solid three phases to fully contact and react within the tubular reactor R1, generating a reaction stream containing cobalt carbonyl. The operating temperature of tubular reactor R1 is 120℃; the operating pressure of tubular reactor R1 is 3.0MPa; the residence time of reaction liquid C in tubular reactor R1 is 5min; the equivalent pore size of the porous gas dispersion structure is 0.1μm; and the axial coverage length of the porous gas dispersion structure accounts for 90% of the effective reaction length of the tubular reactor.

[0032] During the continuous separation process, the reaction stream flowing out of the tubular reactor R1 continuously enters the filtration unit F1, where the reaction stream undergoes solid-liquid separation to remove unreacted solids or by-product solids, resulting in a clear reaction liquid.

[0033] The reaction solution after solid-liquid separation continuously enters a continuous cooling crystallizer R2. In the continuous cooling crystallizer R2, by controlling the cooling conditions, cobalt carbonyl in the reaction solution gradually precipitates and crystallizes to obtain a solid cobalt carbonyl product. The operating temperature of the continuous cooling crystallizer R2 is -35°C. o C, the stay time is 15 minutes.

[0034] After the cobalt carbonyl solid precipitated in the continuous cooling crystallizer R2 is separated from the mother liquor: the cobalt carbonyl solid enters the receiving tank V2 for collection; the separated mother liquor is returned to the feed end of the tubular reactor R1 via the mother liquor reflux unit V1, and mixed with fresh feed A and / or feed B to participate in the reaction again.

[0035] Under the aforementioned continuous reaction conditions, the system achieved stable continuous operation, with no significant uneven gas distribution, reaction instability, or blockage observed during the reaction process. Analysis showed that the yield of the obtained cobalt carbonyl product was 10.42 g / min, with a reaction conversion rate of 95%. During 80 hours of continuous operation, the system remained stable, and product quality fluctuations were minimal. Example 4:

[0036] Based on Example 1, this example attempts to further reduce the average particle size of cobalt hydroxide (Co(OH)₂). Specifically, referring to patent CN101955234B, the median particle size D50 of cobalt hydroxide obtained is 300 nm. Other conditions are the same as in Example 1. Under the above conditions, the yield of the carbonyl cobalt product per unit time is 10.65 g / min, and the reaction conversion rate is 97%. However, because the ultrafine powder easily penetrates the rotary seal gaps, a sealing problem was found after 8 hours of continuous operation. Example 5:

[0037] Using cobalt hydroxide obtained in Example 4 as the reaction raw material, and with other conditions the same as in Example 2, the reaction conversion rate was 99% and the yield per unit time was 11 g / min.

[0038] Examples 6-8:

[0039] Comparative Example 1: In contrast, the integrated porous gas dispersion structure of the above embodiments was replaced with a conventional jet-type gas inlet structure. The gas inlet is a nozzle located at the reactor inlet section. The gas enters the reactor in an axial jet form through the nozzle orifice, mixes with the liquid phase in the jet zone, and forms dispersed bubbles. The nozzle diameter is 0.1 mm. The reaction raw materials and concentration conditions are the same as in Example 1. The reaction conversion rate is less than 25%, and a large amount of remaining cobalt hydroxide and the generated water accumulate, making it difficult to maintain a consistent reaction effect under continuous and long-term stable operation conditions.

[0040] Comparative Example 2: In contrast, the integrated porous gas dispersion structure of the above embodiments was replaced with a conventional single-hole gas inlet structure for centralized gas inlet, and a tubular reactor with an integrated high-shear device was used for the reaction. The raw materials and concentrations of the reaction were the same as in Example 1. The reaction conversion rate was less than 10%, and a large amount of remaining cobalt hydroxide and the generated water accumulated, making it difficult to maintain a consistent reaction effect under continuous and long-term stable operation conditions.

[0041] Comparative Example 3: In comparison, the conditions in this embodiment are basically the same as those in Example 2, except that cobalt carbonyl was not pre-dissolved in the hexane in this embodiment. The reaction liquid collected in the initial stage of the reaction was lighter in color, had a lower gas consumption rate, more solid residue, and lower yield, showing significant differences from the steady-state condition.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A tubular reactor characterized in that, It includes an integrated porous gas dispersion structure and a gas supply chamber; the porous gas dispersion structure has a three-dimensional interconnected pore network structure inside. After the gas required for the reaction enters the gas supply chamber through flow regulation, it passes radially through the porous gas dispersion structure and enters the reaction zone inside the reactor under the action of the radial pressure difference between the gas supply chamber and the inside of the reactor.

2. The tubular reactor according to claim 1, characterized in that The porous gas dispersion structure is arranged along the reactor axis at the front section of the reactor.

3. The tubular reactor of claim 1, wherein, The porous gas dispersion structure is configured as several segmented structures spaced apart from each other along the reactor axis, with each segmented porous structure separated by a solid wall section, to achieve distributed gas entry along the reactor axis.

4. A continuous reaction system, characterized in that, include: The feed unit, the tubular reactor as described in any one of claims 1-3, the solid-liquid separation unit, the continuous crystallization or separation unit, and the mother liquor reflux unit are connected in sequence and coordinated, and the output end of the mother liquor reflux unit is connected to the front end of the tubular reactor.

5. The continuous reaction system according to claim 4, characterized in that, The feeding unit is used to continuously introduce liquid-phase reaction medium and solid reactants, and mix them to form a stable gas-liquid-solid reaction system.

6. The continuous reaction system according to claim 4, characterized in that, The solid-liquid separation unit is located downstream of the tubular reactor and is used to separate unreacted solid reactants or by-product solids in the reaction stream.

7. The continuous reaction system according to claim 4, characterized in that, The mother liquor reflux unit is used to return the mother liquor separated by the continuous crystallization or separation unit to the front end of the tubular reactor, mix it with the fresh feed, and participate in the reaction again.

8. A method for continuous synthesis of cobalt carbonyl, characterized in that, The method employing the tubular reactor according to any one of claims 1-3 and the continuous reaction system according to any one of claims 4-7 comprises the following steps: (1) Liquid reaction medium and solid reactants are continuously introduced into the tubular reactor to form a gas-liquid-solid reaction system; (2) The gas required for the reaction is introduced into the gas supply chamber through flow regulation, so that the gas passes through the porous gas dispersion structure under the action of radial pressure difference and enters the reactor uniformly to contact the reaction system. (3) The gas-liquid-solid three-phase reaction is completed in a tubular reactor to obtain a reaction stream containing cobalt carbonyl; (4) The reaction stream is sequentially subjected to solid-liquid separation, product separation and mother liquor reflux to achieve continuous and stable operation.

9. The method for continuous synthesis of cobalt carbonyl according to claim 8, characterized in that, In step (1), cobalt carbonyl was dissolved in advance.

10. The method for continuous synthesis of cobalt carbonyl according to claim 8, characterized in that, The reaction stream described in step (4) is sequentially fed into the solid-liquid separation unit, the continuous crystallization or separation unit, and the separated mother liquor is returned to the front end of the tubular reactor via the mother liquor reflux unit.

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