On-line segmented activation and regeneration method for rhodium catalyst

Abstract

The method comprises the following steps: introducing a rhodium catalyst solution part to be regenerated in a low-pressure evaporator of an oxo-synthesis reaction system into a first-stage regeneration tower, introducing an impurity-removing regeneration agent into the first-stage regeneration tower, performing countercurrent contact in the first-stage regeneration tower and the second-stage regeneration tower, performing liquid-liquid separation on the impurity-removed rhodium catalyst solution by virtue of a coalescer, and separating the impurity-removed rhodium catalyst solution from the first-stage regeneration tower; after water and liquid drops of an impurity-removing regenerant entrained in the rhodium catalyst solution are removed, the rhodium catalyst solution and a washing regenerant are introduced into a second-stage regeneration tower respectively, the rhodium catalyst solution and the washing regenerant are subjected to countercurrent contact in the second-stage regeneration tower, the residual impurity-removing regenerant in the rhodium catalyst solution is washed and removed, and the rhodium catalyst solution flows through a coalescer to be subjected to liquid-liquid separation to obtain an activated rhodium catalyst solution; if the second-stage regeneration tower is the last-stage regeneration tower, directly and continuously returning to the main reactor of the carbonyl synthesis reaction system; otherwise, introducing the rhodium catalyst solution into the next-stage regeneration tower, and continuously washing and regenerating according to the flow of the second-stage regeneration tower until the last-stage regeneration tower. According to the invention, the carbonyl synthesis reaction system continuously operates for regeneration in a non-stop state.

Description

Technical Field

[0001] This invention belongs to the field of catalyst regeneration and chemical separation technology, and more specifically, it relates to an online segmented activation and regeneration method for rhodium catalysts. Background Technology

[0002] Carbonyl synthesis is an important class of homogeneous complex catalytic reactions. The classic carbonyl synthesis method is a high-pressure process using cobalt carbonyl as a catalyst. However, this method requires high-pressure equipment and generates a significant amount of isomeric aldehydes, leading to continuous improvements over the years. In the 1970s, the carbonyl synthesis industry gained prominence in the petrochemical sector, with the successful industrialization of low-pressure rhodium-phosphine catalytic systems bringing about a significant revolution in carbonyl synthesis methods. Its characteristics, such as relatively mild reaction conditions and few side reactions, are well-known technically. However, with continuous carbonyl synthesis reactions, even in the absence of exogenous catalyst poisoning, rhodium-phosphine catalysts can lose activity or become partially deactivated. The combined effects of reaction process conditions such as reaction temperature, reactant partial pressure, phosphine ligand / rhodium molar ratio, and rhodium concentration can lead to the formation of inactive complex clusters, making catalyst deactivation unavoidable. Regeneration of partially deactivated catalysts is crucial for improving plant efficiency and reducing rhodium consumption.

[0003] Existing patents CN102950027A and CN102950028A describe propargyl alcohol, acetic acid, and triethanolamine, respectively. These are used as regenerators to regenerate rhodium phosphine catalysts at specific temperatures. After regeneration, the catalyst activity increases from 28% to 75%, while the chlorine content decreases from 29 mg / kg to 7 mg / kg. This regeneration process is only effective against the inhibitory agent Cl, and has no effect on other elements such as sulfur (S) and some metals.

[0004] US4861918 discloses a method for regenerating a rhodium-organophosphorus complex carbonylation catalyst. The method involves first mixing the deactivated complex catalyst with an organic reagent in a non-production state; then removing the inhibitor from the carbonyl synthesis catalyst. The regeneration reagent used in the patent is expensive and difficult to obtain, which is not conducive to industrial application.

[0005] US5237106 discloses a process for improving the catalytic activity of a partially deactivated rhodium carbonyl complex catalyst by treating it with propargyl alcohol and carboxylic acid. This patent uses propargyl alcohol and acetic acid as reactants, operates at atmospheric pressure, and neutralizes the catalyst with triethanolamine solution after the reaction. The challenge of this reaction is inhibiting the polymerization of propargyl alcohol during the regeneration process, thereby improving the regeneration activity.

[0006] CN104028311 discloses a chemical regeneration method for a butanol / octanol carbonyl synthesis catalyst. This patent describes a method for washing the butanol / octanol carbonyl synthesis catalyst with three different types of regenerators during non-production conditions to activate its catalytic activity. However, this patent's catalyst regeneration method primarily employs a "shutdown regeneration" mode to restore catalyst activity. Shutting down and restarting the plant can cause significant economic losses and system fluctuations. Furthermore, offline processing and transfer may result in catalyst loss, leading to costly resource waste.

[0007] To overcome the above problems, it is urgent to develop a new and efficient online activation and regeneration technology for rhodium catalysts, which can achieve deep regeneration of catalysts without affecting the continuous production of the main unit, and minimize the loss of precious metals and system fluctuations. Summary of the Invention

[0008] To overcome the shortcomings of existing technologies and address the problems of large downtime losses, numerous side reactions, and easy catalyst loss in existing rhodium catalyst regeneration technologies, this invention proposes an online segmented activation and regeneration method for rhodium catalysts. This method allows for continuous regeneration of the rhodium catalyst without shutting down the carbonyl synthesis reaction system, achieving efficient, continuous, and online activation of the rhodium catalyst, avoiding downtime losses, significantly reducing side reactions and precious metal loss, and having minimal impact on the carbonyl synthesis reaction system.

[0009] The objective of this invention can be achieved through the following technical solutions.

[0010] A method for online segmental activation and regeneration of a rhodium catalyst, wherein the activation and regeneration of the rhodium catalyst is carried out without stopping the carbonyl synthesis reaction system, specifically including the following steps: S1 Initial Regeneration: Part of the rhodium catalyst solution to be regenerated from the low-pressure evaporator of the carbonyl synthesis reaction system is introduced into the lower part of the first-stage regeneration tower, while the regenerating agent is introduced into the upper part of the first-stage regeneration tower, so that the two come into countercurrent contact in the tower to remove impurities from the rhodium catalyst solution. S2 Oil-Water Separation: The rhodium catalyst solution after initial impurity removal and regeneration in step S1 flows through the top coalescer in the first-stage regeneration tower for liquid-liquid separation, removing entrained water and impurity removal and regeneration agent droplets to obtain the initially regenerated rhodium catalyst solution; the aqueous phase in the bottom of the first-stage regeneration tower is discharged to the water treatment system. S3 Washing and Regeneration: The rhodium catalyst solution obtained in step S2 is introduced into the lower part of the next stage regeneration tower, and at the same time, the washing and regeneration agent is introduced into the upper part of the regeneration tower, so that the two come into countercurrent contact in the tower to wash and remove the residual impurity removal regeneration agent in the rhodium catalyst solution. S4 Final Separation and Return System: The rhodium catalyst solution after washing and regeneration in step S3 flows through the top coalescer in its regeneration tower for liquid-liquid separation, removing entrained water and washing regenerator droplets to obtain an activated rhodium catalyst solution. If this regeneration tower is the last stage regeneration tower, the obtained rhodium catalyst solution is directly and continuously returned to the main reactor of the carbonyl synthesis reaction system. If this regeneration tower is not the last stage regeneration tower, the obtained rhodium catalyst solution is introduced into the next stage regeneration tower, and washing and regeneration continue according to the process of steps S3 and S4 until the last stage regeneration tower obtains an activated rhodium catalyst solution, which is then directly and continuously returned to the main reactor of the carbonyl synthesis reaction system. The aqueous phase from the bottom of each stage regeneration tower is discharged to the water treatment system.

[0011] Furthermore, in steps S2 and S4, before being discharged, the aqueous phase in the bottom of each stage of the regeneration tower passes through a packing layer located at the bottom of the tower to separate the rhodium-containing oil phase entrained in the aqueous phase. The packing layer is preferably a Pall ring packing layer.

[0012] Furthermore, the impurity removal regenerator is a mixed solution of regenerator A and regenerator B for removing impurities, and the washing regenerator is regenerator C for washing, which is miscible or reacts with the impurity removal regenerator, but is separable from the main solvent of the rhodium catalyst solution.

[0013] Furthermore, the regenerator A and regenerator B are preferably two tertiary alkyl alcohol amines with different structures, and the mixed solution of regenerator A and regenerator B is preferably an aqueous solution of the two tertiary alkyl alcohol amines in a molar ratio of 1:1 to 5; the regenerator C is preferably desalinated water.

[0014] Furthermore, the regenerator A and regenerator B are two tertiary alkanolamines with different structures, and the mixed solution of regenerator A and regenerator B is an aqueous solution formed by mixing the two tertiary alkanolamines in a molar ratio of 1:1 to 5.

[0015] Furthermore, the tert-alkanolamine is selected from triethanolamine, triisopropanolamine, methyldiethanolamine, or phenyldiethanolamine.

[0016] Furthermore, the regenerant C is demineralized water. Furthermore, the operating pressure of the first-stage regeneration tower is 2.0~2.4MPa, the operating pressure of the remaining regeneration towers is 1.8~2.2MPa, the operating temperature of the first-stage regeneration tower is 60℃~65℃, and the operating temperature of the remaining regeneration towers is 65℃~70℃.

[0017] Furthermore, the aqueous phase discharge flow rate of the first-stage regeneration tower bottom is 760 kg / h to 770 kg / h, and the aqueous phase discharge flow rate of the remaining stages of the regeneration tower bottom is 920 kg / h to 1080 kg / h.

[0018] Furthermore, in the first-stage regeneration tower, the feed flow rate of the rhodium catalyst solution to be regenerated is 2100 kg / h to 2700 kg / h, and the feed flow rate ratio of the impurity removal regenerator to the rhodium catalyst solution to be regenerated is 1:3; in the remaining regeneration towers, the feed flow rate ratio of the washing regenerator to the impurity removal regenerator in the first-stage regeneration tower is 1.2 to 1.4.

[0019] Compared with the prior art, the beneficial effects of the technical solution of the present invention are: (1) The process flow of this invention is applied between the low-pressure evaporator and the main reactor of the carbonyl synthesis reaction system. A portion of the deactivated rhodium catalyst solution is continuously diverted from the bottom of the low-pressure evaporator and introduced into the regeneration tower. Simultaneously, the prepared regenerator continuously enters each stage of the regeneration tower. The two materials achieve continuous countercurrent contact and reaction within the tower, ultimately yielding an activated rhodium catalyst solution, which is then re-transported into the main reactor of the carbonyl synthesis reaction system. This invention allows for the activation and regeneration of the rhodium catalyst without shutting down the carbonyl synthesis reaction system, abandoning the traditional full-scale shutdown and batch processing mode. It achieves parallel production and regeneration, avoiding downtime losses, and the process is stable and controllable.

[0020] (2) In this invention, all regeneration towers are equipped with a coalescer at the top to remove trace amounts of water and regenerator droplets entrained in the regenerated catalyst solution taken from the top of the tower; all regeneration towers are equipped with a packing layer at the bottom to prevent the dispersed rhodium-containing oil phase from agglomerating and merging into large oil droplets through the surface effect of the packing. The coalescer at the top of the regeneration tower and the packing layer at the bottom ensure the purity of the regenerated rhodium catalyst and prevent catalyst loss.

[0021] (3) This invention only processes part of the rhodium catalyst solution to be regenerated in the low-pressure evaporator of the carbonyl synthesis reaction system, and the flow rate is controllable. The regeneration operation has minimal impact on the temperature, pressure, material balance and downstream separation section of the carbonyl synthesis reaction system, thus improving the overall production efficiency and economic benefits. Attached Figure Description

[0022] Figure 1 This is a flowchart of the online segmented activation and regeneration method for the rhodium catalyst in Example 1 of the present invention.

[0023] Figure 2 This is a flowchart of the online segmented activation and regeneration method for the rhodium catalyst in Example 2 of the present invention.

[0024] Figure 3 This is a flowchart of the online segmented activation and regeneration method for the rhodium catalyst in Example 3 of the present invention. Detailed Implementation

[0025] The present invention will now be further described with reference to the accompanying drawings.

[0026] The present invention provides an online segmented activation and regeneration method for rhodium catalysts, applicable to continuous carbonyl synthesis reaction systems, which allows for the activation and regeneration of rhodium catalysts without system shutdown.

[0027] This invention discloses an online segmented activation and regeneration method for rhodium catalysts. Two to four regeneration towers are connected in series between the low-pressure evaporator and the main reactor of a carbonyl synthesis reaction system. The height of each subsequent regeneration tower is less than that of the preceding tower, for example, by 2 meters. Each regeneration tower has a regenerant inlet on its upper side connected to a regenerant input pipeline, and an aqueous phase outlet at the bottom of each regeneration tower connected to an aqueous phase output pipeline. The catalyst solution inlet on the lower side of the first-stage regeneration tower is connected to the bottom of the low-pressure evaporator of the carbonyl synthesis reaction system via a catalyst solution input pipeline. Except for the first-stage regeneration tower, the catalyst solution inlets on the lower sides of each of the remaining regeneration towers are connected via pipelines to the catalyst solution outlet at the top of their corresponding preceding regeneration tower. The catalyst solution outlet at the top of the last regeneration tower is connected to the main reactor of the carbonyl synthesis reaction system via an activated catalyst solution output pipeline.

[0028] In the above method and process, each of the regeneration towers (e.g. Figures 1 to 3 T1, T2, T3, and T4 in the text are all plate towers, and each of the regeneration towers is equipped with a coalescer (such as...) at the top. Figures 1 to 3 J1, J2, J3, and J4 in the text). Each of the aforementioned regeneration towers has a packing layer at its bottom (e.g., ...). Figures 1 to 3 PL1, PL2, PL3, and PL4 in the text refer to a Pall ring packing layer. Before being discharged, the aqueous phase in the bottom of each regeneration tower passes through the packing layer located at the bottom of the tower to separate the rhodium-containing oil phase entrained in the aqueous phase.

[0029] In the above method and process, a regenerant flow control valve (e.g., ...) is installed on the regenerant input pipeline connected to the regenerant inlet of each stage of the regeneration tower. Figures 1 to 3 (F2, F3, F6, F8 in the text), each of the regeneration towers is equipped with a water phase flow control valve (e.g., F2, F3, F6, F8) on the water phase output pipeline connected to the water phase outlet. Figures 1 to 3 (F4, F5, F7, F9 in the text), the catalyst solution inlet of the first-stage regeneration tower is connected to a catalyst solution input pipeline with a catalyst flow control valve (e.g., F4, F5, F7, F9), and a catalyst flow control valve is installed on the pipeline for the catalyst solution to be regenerated (e.g., F4, F5, F7, F9). Figures 1 to 3 (F1 in the text), the above flow control valves (such as F1), Figures 1 to 3 All of the components (F1~F9) can be controlled independently. The flow rates of the rhodium catalyst solution to be regenerated, the impurity removal regenerator, and the washing regenerator are all independently controlled, enabling low-flow, continuous online operation. Furthermore, the proportion of the catalyst solution flow rate drawn from the low-pressure evaporator to the total flow rate is adjustable.

[0030] The specific process of the online segmented activation and regeneration method for rhodium catalyst of the present invention includes the following steps: S1 Initial Regeneration: Part of the rhodium catalyst solution to be regenerated from the low-pressure evaporator of the carbonyl synthesis reaction system is introduced into the lower part of the first-stage regeneration tower, while the regenerating agent is introduced into the upper part of the first-stage regeneration tower, so that the two come into countercurrent contact in the tower to remove impurities from the rhodium catalyst solution. S2 Oil-Water Separation: The rhodium catalyst solution after initial impurity removal and regeneration in step S1 flows through the top coalescer in the first-stage regeneration tower for liquid-liquid separation, removing entrained water and impurity removal and regeneration agent droplets to obtain the initially regenerated rhodium catalyst solution; the aqueous phase in the bottom of the first-stage regeneration tower is discharged to the water treatment system. S3 Washing and Regeneration: The rhodium catalyst solution obtained in step S2 is introduced into the lower part of the next stage regeneration tower, and at the same time, the washing and regeneration agent is introduced into the upper part of the regeneration tower, so that the two come into countercurrent contact in the tower to wash and remove the residual impurity removal regeneration agent in the rhodium catalyst solution. S4 Final Separation and Return System: The rhodium catalyst solution after washing and regeneration in step S3 flows through the top coalescer in its regeneration tower for liquid-liquid separation, removing entrained water and washing regenerator droplets to obtain an activated rhodium catalyst solution. If this regeneration tower is the last stage regeneration tower, the obtained rhodium catalyst solution is directly and continuously returned to the main reactor of the carbonyl synthesis reaction system. If this regeneration tower is not the last stage regeneration tower, the obtained rhodium catalyst solution is introduced into the next stage regeneration tower, and washing and regeneration continue according to the process of steps S3 and S4 until the last stage regeneration tower obtains an activated rhodium catalyst solution, which is then directly and continuously returned to the main reactor of the carbonyl synthesis reaction system. The aqueous phase from the bottom of each stage regeneration tower is discharged to the water treatment system.

[0031] In the above method, the impurity removal regenerator is a mixed solution of regenerator A and regenerator B for removing impurities, and the washing regenerator is regenerator C for washing, which is miscible or reacts with the impurity removal regenerator, but is separable from the main solvent of the rhodium catalyst solution. Preferably, the regenerator C is demineralized water. The regenerator A and regenerator B are two tertiary alkyl alcohol amines with different structures, and the mixed solution of regenerator A and regenerator B is an aqueous solution formed by mixing the two tertiary alkyl alcohol amines in a molar ratio of 1:1 to 5. The tertiary alkyl alcohol amine can be selected from triethanolamine, triisopropanolamine, methyldiethanolamine, or phenyldiethanolamine. The general formula for tertiary alkyl alcohol amines is RN(R1R2), where R represents a hydroxyalkyl group with 2 to 4 carbon atoms, and R1 and R2 both represent alkyl groups with 1 to 4 carbon atoms, hydroxyalkyl groups with 2 to 4 carbon atoms, or phenyl groups.

[0032] In the above method, preferably, the operating pressure of the first-stage regeneration tower is 2.0~2.4 MPa, and the operating pressure of the remaining regeneration towers is 1.8~2.2 MPa. The operating temperature of the first-stage regeneration tower is 60℃~65℃, and the operating temperature of the remaining regeneration towers is 65℃~70℃.

[0033] The aqueous phase discharge flow rate of the first-stage regeneration tower bottom is 760 kg / h to 770 kg / h, and the aqueous phase discharge flow rate of the remaining stages of the regeneration tower bottom is 920 kg / h to 1080 kg / h.

[0034] In the first-stage regeneration tower, the feed flow rate of the rhodium catalyst solution to be regenerated is 2100 kg / h to 2700 kg / h, and the feed flow rate ratio of the impurity removal regenerator to the rhodium catalyst solution to be regenerated is 1:3; in the other regeneration towers, the feed flow rate ratio of the washing regenerator to the impurity removal regenerator in the first-stage regeneration tower is 1.2 to 1.4.

[0035] Example 1 Based on the above-mentioned process principle, in this embodiment, two regeneration towers are connected in series between the low-pressure evaporator and the main reactor of the carbonyl synthesis reaction system, such as... Figure 1 As shown. The specific process of the online segmented activation and regeneration method for the rhodium catalyst in this embodiment includes the following steps: S1 Initial Regeneration: The rhodium catalyst solution to be regenerated from the low-pressure evaporator of the carbonyl synthesis reaction system is introduced into the lower part of the first-stage regeneration tower T1 at a flow rate of 2100 kg / h; simultaneously, the regenerating agent Z1 (i.e., an aqueous solution of triisopropanolamine and triethanolamine mixed in a molar ratio of 1:1) is introduced into the upper part of the first-stage regeneration tower T1 at a flow rate of 700 kg / h; under a temperature of 60°C and a pressure of 2.2 MPa, the two are brought into countercurrent contact within the tower to remove impurities from the rhodium catalyst solution; S2 Oil-Water Separation: The rhodium catalyst solution after initial impurity removal and regeneration in step S1 flows through the coalescer J1 in the first-stage regeneration tower T1 for liquid-liquid separation, removing the entrained water and droplets of the impurity removal and regeneration agent Z1 to obtain the initially regenerated rhodium catalyst solution; the aqueous phase in the bottom of the first-stage regeneration tower T1 passes through the packing layer PL1 and is discharged to the water treatment system at a flow rate of 760 kg / h. S3 Washing and Regeneration: The initial regenerated rhodium catalyst solution obtained in step S2 is completely introduced into the lower part of the second-stage regeneration tower T2; at the same time, washing regenerator Z2 (i.e., demineralized water) is introduced into the upper part of the second-stage regeneration tower T2 at a flow rate of 840 kg / h; at a temperature of 65°C and a pressure of 2.0 MPa, the two are made to come into countercurrent contact in the tower to wash and remove the residual impurity removal regenerator Z1 in the rhodium catalyst solution; S4 Final Separation and Return System: The rhodium catalyst solution after washing and regeneration in step S3 flows through the coalescer J2 in the second-stage regeneration tower T2 for liquid-liquid separation, removing the entrained water and washing regenerator Z2 (i.e., demineralized water) droplets to obtain the activated and regenerated rhodium catalyst solution, which is continuously returned to the main reactor of the carbonyl synthesis reaction system; the aqueous phase in the bottom of the second-stage regeneration tower T2 passes through the packing layer PL2 and is discharged to the water treatment system at a flow rate of 920 kg / h.

[0036] After chemically regenerating the rhodium catalyst using the method of this embodiment, portions of the rhodium catalyst solution to be regenerated and the rhodium catalyst solution activated according to the method of this embodiment were taken from sampling points, and activity tests were conducted using a 300mL autoclave. Specifically, the rhodium catalyst solution was added to the reaction vessel and sealed. Then, the atmosphere inside the vessel was replaced three times with nitrogen and a mixed gas of propylene, carbon monoxide, and hydrogen in a molar ratio of 1:1:1. The mixed gas was pressurized to 1.8MPa (gauge pressure), heated to 85°C, and the pressure inside the reaction vessel was maintained at 1.8MPa. Gas consumption was observed. When no further gas consumption occurred (reaction time 0.5 hours), the reaction vessel was cooled and depressurized. Gas chromatography analysis of the reaction solution was used to compare the activities of the rhodium catalyst solution to be regenerated and the rhodium catalyst solution activated according to the method of this embodiment. It was found that the activity of the rhodium catalyst increased from the original 32% to approximately 58%.

[0037] Example 2 Based on the above-mentioned process principle, in this embodiment, three regeneration towers are connected in series between the low-pressure evaporator and the main reactor of the carbonyl synthesis reaction system, such as... Figure 2 As shown. The specific process of the online segmented activation and regeneration method for the rhodium catalyst in this embodiment includes the following steps: S1 Initial Regeneration: The rhodium catalyst solution to be regenerated from the low-pressure evaporator of the carbonyl synthesis reaction system is introduced into the lower part of the first-stage regeneration tower T1 at a flow rate of 2400 kg / h; simultaneously, the regenerating agent Z1 (i.e., an aqueous solution of methyl diethanolamine and triethanolamine mixed in a molar ratio of 1:3) is introduced into the upper part of the first-stage regeneration tower T1 at a flow rate of 800 kg / h; under a temperature of 63°C and a pressure of 2.0 MPa, the two are brought into countercurrent contact within the tower to remove impurities from the rhodium catalyst solution; S2 Oil-Water Separation: The rhodium catalyst solution after initial impurity removal and regeneration in step S1 flows through the coalescer J1 in the first-stage regeneration tower T1 for liquid-liquid separation, removing the entrained water and droplets of the impurity removal and regeneration agent Z1 to obtain the initially regenerated rhodium catalyst solution; the aqueous phase in the bottom of the first-stage regeneration tower T1 passes through the packing layer PL1 and is discharged to the water treatment system at a flow rate of 765 kg / h. S3 Washing and Regeneration: The initial regenerated rhodium catalyst solution obtained in step S2 is completely introduced into the lower part of the second-stage regeneration tower T2; at the same time, washing regenerator Z2 (i.e., demineralized water) is introduced into the upper part of the second-stage regeneration tower T2 at a flow rate of 1040 kg / h; at a temperature of 67°C and a pressure of 1.8 MPa, the two are made to come into countercurrent contact in the tower to wash and remove the residual impurity removal regenerator Z1 in the rhodium catalyst solution; S4: The rhodium catalyst solution after washing and regeneration in step S3 flows through the coalescer J2 in the second-stage regeneration tower T2 for liquid-liquid separation, removing the entrained water and droplets of washing and regenerating agent Z2 to obtain a preliminarily activated rhodium catalyst solution; the aqueous phase in the bottom of the second-stage regeneration tower T2 passes through the packing layer PL2 and is discharged to the water treatment system at a flow rate of 1000 kg / h. S5: The preliminarily activated rhodium catalyst solution obtained in step S4 is introduced entirely into the lower part of the third-stage regeneration tower T3; at the same time, the washing regenerator Z2 is introduced into the upper part of the third-stage regeneration tower T3 at a flow rate of 1040 kg / h; at a temperature of 67°C and a pressure of 1.8 MPa, the two are brought into countercurrent contact in the tower to perform washing and regeneration again, so as to further wash and remove the residual impurity removal regenerator Z1 in the rhodium catalyst solution; S6: The rhodium catalyst solution after washing and regeneration in step S5 flows through the coalescer J3 in the third-stage regeneration tower T3 for liquid-liquid separation, removing the entrained water and droplets of washing regenerator Z2 to obtain the finally activated and regenerated rhodium catalyst solution, which is continuously returned to the main reactor of the carbonyl synthesis reaction system; the aqueous phase in the bottom of the third-stage regeneration tower T3 passes through the packing layer PL3 and is discharged to the water treatment system at a flow rate of 1000 kg / h.

[0038] After chemically regenerating the rhodium catalyst using the method of this embodiment, a portion of the rhodium catalyst solution to be regenerated and the rhodium catalyst solution activated according to the method of this embodiment were taken from the sampling point. An activity test experiment was conducted using a 300mL autoclave (the experimental procedure is the same as in Example 1). It was found that the activity of the rhodium catalyst increased from the original 30% to about 60%.

[0039] Example 3 Based on the above-mentioned process principle, in this embodiment, four regeneration towers are connected in series between the low-pressure evaporator and the main reactor of the carbonyl synthesis reaction system, such as... Figure 3 As shown. The specific process of the online segmented activation and regeneration method for the rhodium catalyst in this embodiment includes the following steps: S1 Initial Regeneration: The rhodium catalyst solution to be regenerated from the low-pressure evaporator of the carbonyl synthesis reaction system is introduced into the lower part of the first-stage regeneration tower T1 at a flow rate of 2700 kg / h; simultaneously, the regenerating agent Z1 (i.e., an aqueous solution of phenyldiethanolamine and triethanolamine mixed in a molar ratio of 1:5) is introduced into the upper part of the first-stage regeneration tower T1 at a flow rate of 900 kg / h; under a temperature of 65°C and a pressure of 2.4 MPa, the two are brought into countercurrent contact in the tower to remove impurities from the rhodium catalyst solution; S2 Oil-Water Separation: The rhodium catalyst solution after initial impurity removal and regeneration in step S1 flows through the coalescer J1 in the first-stage regeneration tower T1 for liquid-liquid separation, removing the entrained water and droplets of the impurity removal and regeneration agent Z1 to obtain the initially regenerated rhodium catalyst solution; the aqueous phase in the bottom of the first-stage regeneration tower T1 passes through the packing layer PL1 and is discharged to the water treatment system at a flow rate of 770 kg / h. S3 Washing and Regeneration: The initial regenerated rhodium catalyst solution obtained in step S2 is completely introduced into the lower part of the second-stage regeneration tower T2; at the same time, washing regenerator Z2 (i.e., demineralized water) is introduced into the upper part of the second-stage regeneration tower T2 at a flow rate of 1260 kg / h; at a temperature of 70°C and a pressure of 2.2 MPa, the two are made to come into countercurrent contact in the tower to wash and remove the residual impurity removal regenerator Z1 in the rhodium catalyst solution; S4: The rhodium catalyst solution after washing and regeneration in step S3 flows through the coalescer J2 in the second-stage regeneration tower T2 for liquid-liquid separation, removing the water and droplets of washing and regenerating agent Z2 entrained therein, and obtaining a preliminarily activated rhodium catalyst solution; the aqueous phase in the bottom of the second-stage regeneration tower T2 passes through the packing layer PL2 and is discharged to the water treatment system at a flow rate of 1080 kg / h. S5: The preliminarily activated rhodium catalyst solution obtained in step S4 is introduced entirely into the lower part of the third-stage regeneration tower T3; at the same time, the washing regenerator Z2 is introduced into the upper part of the third-stage regeneration tower T3 at a flow rate of 1260 kg / h; at a temperature of 70°C and a pressure of 2.2 MPa, the two are made to come into countercurrent contact in the tower to wash and regenerate again, so as to further wash and remove the residual impurity removal regenerator Z1 in the rhodium catalyst solution; S6: The rhodium catalyst solution after washing and regeneration in step S5 flows through the coalescer J3 in the third-stage regeneration tower T3 for liquid-liquid separation to remove the entrained water and droplets of washing regenerator Z2, and obtain the reactivated rhodium catalyst solution; the aqueous phase in the bottom of the third-stage regeneration tower T3 passes through the packing layer PL3 and is discharged to the water treatment system at a flow rate of 1080 kg / h. S7: The reactivated rhodium catalyst solution obtained in step S6 is completely introduced into the lower part of the fourth-stage regeneration tower T4; at the same time, the washing regenerator Z2 is introduced into the upper part of the fourth-stage regeneration tower T4 at a flow rate of 1260 kg / h; at a temperature of 70°C and a pressure of 2.2 MPa, the two are made to come into countercurrent contact in the tower to wash and regenerate again, so as to further wash and remove the residual impurity removal regenerator Z1 in the rhodium catalyst solution; S8: The rhodium catalyst solution after washing and regeneration in step S7 flows through the coalescer J4 in the fourth-stage regeneration tower T4 for liquid-liquid separation, removing the entrained water and droplets of washing regenerator Z2, to obtain the finally activated and regenerated rhodium catalyst solution, which is continuously returned to the main reactor of the carbonyl synthesis reaction system; the aqueous phase in the bottom of the fourth-stage regeneration tower T4 passes through the packing layer PL4 and is discharged to the water treatment system at a flow rate of 1080 kg / h.

[0040] After chemically regenerating the rhodium catalyst using the method of this embodiment, a portion of the rhodium catalyst solution to be regenerated and the rhodium catalyst solution activated according to the method of this embodiment were taken from the sampling point. An activity test experiment was conducted using a 300mL autoclave (the experimental procedure is the same as in Example 1). It was found that the activity of the rhodium catalyst increased from the original 31% to about 62%.

[0041] Although the functions and working processes of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific functions and working processes described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these are within the protection scope of the present invention.

Claims

1. A method for online segmented activation and regeneration of a rhodium catalyst, characterized in that, This method involves activating and regenerating the rhodium catalyst while the carbonyl synthesis reaction system remains operational. The specific steps include: S1 Initial Regeneration: Part of the rhodium catalyst solution to be regenerated from the low-pressure evaporator of the carbonyl synthesis reaction system is introduced into the lower part of the first-stage regeneration tower, while the regenerating agent is introduced into the upper part of the first-stage regeneration tower, so that the two come into countercurrent contact in the tower to remove impurities from the rhodium catalyst solution. S2 Oil-Water Separation: The rhodium catalyst solution after initial impurity removal and regeneration in step S1 flows through the top coalescer in the first-stage regeneration tower for liquid-liquid separation, removing entrained water and impurity removal and regeneration agent droplets to obtain the initially regenerated rhodium catalyst solution; the aqueous phase in the bottom of the first-stage regeneration tower is discharged to the water treatment system. S3 Washing and Regeneration: The rhodium catalyst solution obtained in step S2 is introduced into the lower part of the next stage regeneration tower, and at the same time, the washing and regeneration agent is introduced into the upper part of the regeneration tower, so that the two come into countercurrent contact in the tower to wash and remove the residual impurity removal regeneration agent in the rhodium catalyst solution. S4 Final Separation and Return System: The rhodium catalyst solution after washing and regeneration in step S3 flows through the top coalescer in its regeneration tower for liquid-liquid separation, removing entrained water and washing regenerator droplets to obtain an activated rhodium catalyst solution. If this regeneration tower is the last stage regeneration tower, the obtained rhodium catalyst solution is directly and continuously returned to the main reactor of the carbonyl synthesis reaction system. If this regeneration tower is not the last stage regeneration tower, the obtained rhodium catalyst solution is introduced into the next stage regeneration tower, and washing and regeneration continue according to the process of steps S3 and S4 until the last stage regeneration tower obtains an activated rhodium catalyst solution, which is then directly and continuously returned to the main reactor of the carbonyl synthesis reaction system. The aqueous phase from the bottom of each stage regeneration tower is discharged to the water treatment system.

2. The online segmented activation and regeneration method for rhodium catalyst according to claim 1, characterized in that, In steps S2 and S4, before being discharged, the aqueous phase in the bottom of each stage of the regeneration tower passes through a packing layer located at the bottom of the tower to separate the rhodium-containing oil phase entrained in the aqueous phase. The packing layer is preferably a Pall ring packing layer.

3. The online segmented activation and regeneration method for rhodium catalyst according to claim 1, characterized in that, The impurity removal regenerator is a mixed solution of regenerator A and regenerator B for removing impurities, and the washing regenerator is regenerator C for washing. It is miscible or reacts with the impurity removal regenerator, but is separable from the main solvent of the rhodium catalyst solution.

4. The online segmented activation and regeneration method for rhodium catalyst according to claim 3, characterized in that, The regenerator A and regenerator B are two tertiary alkyl alcohol amines with different structures, and the mixed solution of regenerator A and regenerator B is an aqueous solution formed by mixing the two tertiary alkyl alcohol amines in a molar ratio of 1:1 to 5.

5. The online segmented activation and regeneration method for rhodium catalyst according to claim 3, characterized in that, The tert-alkanolamine is selected from triethanolamine, triisopropanolamine, methyldiethanolamine or phenyldiethanolamine.

6. The online segmented activation and regeneration method for rhodium catalyst according to claim 3, characterized in that, The regenerant C is demineralized water.

7. The online segmented activation and regeneration method for rhodium catalyst according to claim 1, characterized in that, The operating pressure of the first-stage regeneration tower is 2.0~2.4MPa, and the operating pressure of the remaining regeneration towers is 1.8~2.2MPa. The operating temperature of the first-stage regeneration tower is 60℃~65℃, and the operating temperature of the remaining regeneration towers is 65℃~70℃.

8. The online segmented activation and regeneration method for rhodium catalyst according to claim 1, characterized in that, The aqueous phase discharge flow rate of the first-stage regeneration tower bottom is 760 kg / h to 770 kg / h, and the aqueous phase discharge flow rate of the remaining stages of the regeneration tower bottom is 920 kg / h to 1080 kg / h.

9. The online segmented activation and regeneration method for rhodium catalyst according to claim 1, characterized in that, In the first-stage regeneration tower, the feed flow rate of the rhodium catalyst solution to be regenerated is 2100 kg / h to 2700 kg / h, and the feed flow rate ratio of the impurity removal regenerator to the rhodium catalyst solution to be regenerated is 1:3; in the other regeneration towers, the feed flow rate ratio of the washing regenerator to the impurity removal regenerator in the first-stage regeneration tower is 1.2 to 1.4.

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