Process device for hydrocarbonylation reaction of m-cresol and p-cresol under catalysis of solid acid

Abstract

The utility model relates to a process device for hydrocarbonylation reaction of m-cresol and p-cresol under catalysis of solid acid. An outlet of a premixing tank is communicated with a first centrifugal pump and then is communicated with the lower part of a reactor; a gas outlet of the first steel cylinder is communicated with the reactor; the lower part of the reactor is sequentially communicated with a second centrifugal pump and a liquid storage tank. The premixing tank is used for pre-stirring and mixing an m-cresol solution and a solid acid catalyst to form reaction slurry; the first centrifugal pump is used for introducing reaction slurry into the reactor; the high-pressure isobutene liquid in the first steel cylinder is depressurized into gas and then enters the reactor; cresol, a solid acid catalyst and isobutene are mixed in the reactor at a set temperature for a catalytic alkylation reaction; the second centrifugal pump is used for extracting the completely reacted alkylation mixed product out of the reactor, the alkylation mixed product is stored in the liquid storage tank, and the solid acid catalyst is left to stand and settled, so that in-situ separation of a liquid-phase product and a solid-phase catalyst is realized.

Description

Technical Field

[0001] This utility model relates to the field of chemical separation technology of meta- and para-mixed cresols, and particularly to a process apparatus for the meta- and para-mixed cresol alkylation reaction catalyzed by solid acid. Background Technology

[0002] Due to the small 0.5°C difference in boiling points between m-cresol and p-cresol (202.3°C and 201.8°C respectively at atmospheric pressure), conventional distillation methods are insufficient for efficient separation. Chemical alkylation for the separation of m- and p-cresol has gained increasing attention and research due to its advantages of low overall cost, high product quality, and flexible product diversification. The alkylation reaction of m- and p-cresols with isobutylene is a key step in this alkylation separation method. The complexity of the alkylation products, including oligomers of isobutylene, mono-tert-butyl products of m- and p-cresol, and di-tert-butyl products of m- and p-cresol, makes selective control of the target product extremely difficult, requiring a high degree of synergy between the catalytic reaction process and the equipment.

[0003] To avoid using highly corrosive proton acids (concentrated H2SO4, concentrated H3PO4), the use of green and efficient solid acid catalysts to catalyze the alkylation reaction of m- and p-cresol with tert-butyl alkylating agents (isobutylene or methyl tert-butyl ether) has gradually become a research hotspot (Shi Huchao, Research on the process of separating m- and p-cresol mixtures by alkylation, 2014, East China University of Science and Technology; Xie Liuhu, Research on the separation of mixed cresol index antioxidants BHT and 300 by alkylation, 2010, China University of Petroleum).

[0004] Patent CN106831355 discloses a method and process apparatus for high-pressure fixed-bed alkylation of mixed cresols. This invention uses a strong acidic cationic resin (Amberlyst 15) as a catalyst and isobutylene containing 70-90% volumetric additives as an alkylating agent. Under high pressure (1.7-4.2 MPa), the m-p-cresol can undergo an alkylation reaction with liquefied isobutylene. Although this process significantly improves the utilization efficiency of raw materials, the high pressure conditions also exacerbate the self-polymerization reaction of isobutylene, which greatly reduces the effective utilization rate of high-priced isobutylene.

[0005] Patent CN104496759 discloses a method and process apparatus for the fixed-bed alkylation separation of m-p-cresol. This invention uses m-p-cresol and isobutylene as raw materials and a supported acidic ionic liquid as a catalyst to carry out the alkylation reaction in a fixed bed. While the fixed-bed process enables continuous feed and discharge, the gas-liquid reaction results in insufficient contact between the two phases. The short residence time of isobutylene in the mixed phenol liquid leads to incomplete reaction. Although reducing the space velocity can increase the contact between the two phases, it inevitably significantly reduces operating efficiency. Utility Model Content

[0006] The purpose of this invention is to provide a process apparatus for the alkylation reaction of mixed cresols by solid acid catalysis, thereby solving the aforementioned problems existing in the prior art.

[0007] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:

[0008] A process apparatus for the solid acid-catalyzed alkylation reaction of mixed cresols includes a feed unit, a reaction unit, and a product solid-liquid separation unit.

[0009] The feeding unit includes a liquid-solid phase feeding unit and a gas phase feeding unit;

[0010] The liquid-solid feed unit includes a premix tank and a first centrifugal pump;

[0011] The gas phase feeding unit is the first steel cylinder;

[0012] The reaction unit is a reactor;

[0013] The solid-liquid separation unit of the product includes a second centrifugal pump and a liquid storage tank;

[0014] The outlet of the premixing tank is connected to the first centrifugal pump and then to the lower part of the reactor; the outlet of the first gas cylinder is connected to the reactor; the lower part of the reactor is connected in sequence to the second centrifugal pump and the liquid storage tank.

[0015] Based on the above technical solution, the present invention can be further improved as follows.

[0016] Furthermore, it also includes a gas recovery unit, which comprises a condenser, a gas storage tank, a compressor, and a second gas cylinder that are sequentially connected to the upper part of the reactor.

[0017] Furthermore, it also includes an isobutylene mass flow meter, which is installed at the outlet of the first gas cylinder; it also includes an isobutylene rotor flow meter, which is installed on the pipeline between the outlet of the condenser and the gas storage tank.

[0018] Furthermore, the reactor is a batch-type slurry bed reactor, and a stirrer is installed on the central axis of the reactor. Multiple layers of porous gas distributors are horizontally spaced from bottom to top inside the reactor.

[0019] The beneficial effects of this invention are as follows: Isobutylene is relatively prone to oligomerization under certain temperatures and acid catalysts. This side reaction is mainly affected by the concentration of isobutylene. Therefore, isobutylene is fed through aeration, which rapidly forms micron-sized bubbles that disperse quickly within the reaction system, preventing isobutylene aggregation and self-polymerization. Simultaneously, the porous gas distributor further promotes sufficient contact between isobutylene, m-, p-cresol, and catalyst particles, improving the alkylation reaction efficiency. As the alkylation reaction proceeds, the amount of mono-, tert-butylcresol and di-, tert-butylcresol products gradually increases, and the reaction system gradually becomes viscous. Therefore, by using an anchor-frame stirrer, sufficient contact between the gas, liquid, and solid phases within the reaction system can be maintained at all times. At the same time, rapid stirring avoids the adverse effects of localized temperature runaway caused by the exothermic alkylation reaction. Furthermore, the extent of the alkylation reaction can be determined by measuring the isobutylene flow rate at the isobutylene outlet. As the reaction proceeds, the isobutylene flow rate at the reactor outlet will gradually increase. When the isobutylene flow rate displayed by the isobutylene rotor flow meter is approximately equal to the isobutylene mass flow rate set at the inlet, it can be determined that the reaction has been completed, avoiding the need for continuous intermittent sampling and analysis. By placing the completely alkylated mixture in a storage tank, the automatic settling property of the solid acid catalyst particles can be utilized to easily and efficiently separate the alkylation liquid phase product from the solid phase catalyst, avoiding the need for additional filtration devices. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the process apparatus for the solid acid catalytic reaction of mixed cresols according to the present invention.

[0021] The attached diagram lists the components represented by each number as follows:

[0022] 1. Premixing tank; 2. First centrifugal pump; 3. Reactor; 4. First gas cylinder; 5. Isobutylene mass flow meter; 6. Condenser; 7. Isobutylene rotor flow meter; 8. Gas storage tank; 9. Compressor; 10. Liquid storage tank; 11. Second gas cylinder; 12. Second centrifugal pump; 13. Agitator; 14. Porous gas distributor; 15. Aeration disc. Detailed Implementation

[0023] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0024] Example 1

[0025] like Figure 1 As shown, a process apparatus for the alkylation reaction of mixed cresols using solid acid catalysis includes a feeding unit, a reaction unit, and a product solid-liquid separation unit.

[0026] The feeding unit includes a liquid-solid phase feeding unit and a gas phase feeding unit;

[0027] The liquid-solid phase feeding unit includes a premix tank 1 and a first centrifugal pump 2;

[0028] The gas phase feeding unit is the first steel cylinder 4;

[0029] The reaction unit is reactor 3;

[0030] The solid-liquid separation unit of the product includes a second centrifugal pump 12 and a liquid storage tank 10;

[0031] The outlet of the premix tank 1 is connected to the first centrifugal pump 2 and then to the lower part of the reactor 3; the outlet of the first gas cylinder 4 is connected to the reactor 3; the lower part of the reactor 3 is connected to the second centrifugal pump 12 and the liquid storage tank 10 in sequence.

[0032] Premix tank 1 is used to pre-stir and mix p-cresol solution and solid acid catalyst to form reaction slurry; first centrifugal pump 2 passes the reaction slurry into reactor 3; high-pressure isobutylene liquid in first cylinder 4 is depressurized into gas and then enters reactor 3; reactor 3 mixes cresol, solid acid catalyst and isobutylene at a predetermined temperature to carry out catalytic alkylation reaction; second centrifugal pump 12 extracts the completely alkylated mixture from reactor 3, the alkylated mixture is stored in storage tank 10, and the solid acid catalyst is allowed to settle, realizing in-situ separation of liquid phase product and solid phase catalyst.

[0033] Example 2

[0034] like Figure 1 As shown, this embodiment is a further improvement on embodiment 1, as detailed below:

[0035] It also includes a gas recovery unit, which comprises a condenser 6, a gas storage tank 8, a compressor 9, and a second steel cylinder 11, all connected in sequence to the upper part of the reactor 3. The condenser 6 is used to cool and reflux the hydrocarbonated liquid carried out by the unreacted isobutylene gas; the gas storage tank 8 is used to temporarily recover unreacted isobutylene gas at atmospheric pressure; and the compressor 9 compresses the atmospheric pressure isobutylene into the second steel cylinder 11 to form high-pressure isobutylene liquid for recycling.

[0036] Example 3

[0037] like Figure 1 As shown, this embodiment is a further improvement on embodiment 2, as detailed below:

[0038] It also includes an isobutylene mass flow meter 5, which is installed at the outlet of the first gas cylinder 4. The isobutylene mass flow meter 5 is used to control the isobutylene to enter the reactor 3 at a constant flow rate.

[0039] It also includes an isobutylene rotor flow meter 7, which is installed on the pipeline between the outlet of the condenser 6 and the gas storage tank 8. The isobutylene rotor flow meter 7 is used to measure the flow rate of unreacted isobutylene and, in conjunction with the isobutylene mass flow meter 5, can determine the extent of the alkylation reaction. As the reaction proceeds, the isobutylene flow rate at the outlet of reactor 3 will gradually increase. When the isobutylene flow rate displayed by the isobutylene rotor flow meter 7 is approximately equal to the flow rate set by the isobutylene mass flow meter 5 at the inlet, it can be determined that the reaction has been completed, avoiding the need for continuous intermittent sampling and analysis to determine whether the reaction has been completed.

[0040] Example 4

[0041] like Figure 1 As shown, this embodiment is a further improvement on embodiment 3, as detailed below:

[0042] The outlet of the first gas cylinder 4 extends into the reactor 3 from the bottom, and an aeration disc 15 is installed at the outlet. This allows isobutylene to enter the reactor 3 for efficient mixing via aeration. In practice, the aeration disc 15 is made of titanium alloy.

[0043] Example 5

[0044] like Figure 1 As shown, this embodiment is a further improvement on embodiment 4, as detailed below:

[0045] Reactor 3 is a stirred tank slurry bed reactor, with a stirrer 13 installed along its central axis. Multiple layers of porous gas distributors 14 are horizontally spaced from bottom to top inside the reactor. The porous gas distributors 14 further promote the uniform dispersion of isobutylene gas within the reactor 3, ensuring sufficient contact with the mixed cresol and solid acid catalyst; the stirrer 13 promotes the high dispersion of the solid acid catalyst. In specific implementations, the stirrer 13 is an anchor-frame type stirrer 13.

[0046] Since isobutylene readily undergoes oligomerization under certain temperatures and acid catalysts, and this side reaction is mainly affected by the concentration of isobutylene, isobutylene is fed using an aeration method. This allows for the rapid formation of micron-sized bubbles that quickly disperse within the reaction system, preventing isobutylene aggregation and self-polymerization. Simultaneously, the porous gas distributor 14 further promotes sufficient contact between isobutylene, m-, p-cresol, and catalyst particles, improving the alkylation reaction efficiency. As the alkylation reaction proceeds, the generated mono-, tert-butylcresol and di-, tert-butylcresol products gradually increase, and the reaction system gradually becomes viscous. Therefore, using an anchor-frame stirrer ensures sufficient contact between the gas, liquid, and solid phases within the reaction system, while rapid stirring prevents the adverse effects of localized temperature runaway caused by the exothermic alkylation reaction. Furthermore, the extent of the alkylation reaction can be determined by measuring the isobutylene flow rate at the isobutylene outlet using an isobutylene rotor flow meter 7. As the reaction proceeds, the isobutylene flow rate at the reactor 3 outlet gradually increases. When the isobutylene flow rate displayed by the isobutylene rotor flow meter 7 is approximately equal to the isobutylene mass flow rate set at the inlet gas meter 5, it can be determined that the reaction has been completed, avoiding the need for continuous intermittent sampling and analysis. By placing the completely reacted hydrocarbon mixture in the storage tank 10, the automatic settling property of the solid acid catalyst particles can be utilized to easily and efficiently separate the hydrocarbon liquid phase product from the solid phase catalyst, avoiding the need for additional filtration devices.

[0047] The method for the alkylation reaction of m- and p-cresols catalyzed by solid acid includes the following steps: m- and p-cresols and a solid acid catalyst are pre-mixed in a premixing tank 1 and introduced into a reactor 3 via a first centrifugal pump 2. The mixture is stirred and heated to a preset temperature at a preset speed. After the pressure of the high-pressure isobutylene liquid is reduced, it enters the reactor 3 from the bottom of the reactor 3 via an aeration plate 15 at a preset flow rate through an isobutylene mass flow meter 5, and the alkylation reaction begins. After the isobutylene reacts fully with m- and p-cresols and the solid acid catalyst, the reactor 3 is heated. The completely reacted solid-liquid phase alkylation mixture is then centrifuged by a second centrifugal pump 12 and placed in a storage tank 10. After standing for a period of time, the catalyst automatically settles to the bottom to achieve solid-liquid separation. The upper layer is the alkylation reaction product, which is then subjected to subsequent distillation separation. The bottom catalyst is regenerated and recycled.

[0048] Unreacted isobutylene gas from the alkylation reaction is cooled by condenser 6 and enters gas storage tank 8 through isobutylene rotor flow meter 7. When gas storage tank 8 reaches the preset volume, compressor 9 is started to compress it into high-pressure isobutylene liquid for recycling.

[0049] The solid acid catalyst is one or more of macroporous strong acid cation exchange resin particles or supported phosphotungstic acid catalysts. Specific Implementation Example 1

[0051] First, 228.5 kg of m-p-cresol (94.5% purity) and 150 kg of strong acidic cationic resin particles are pre-mixed in a premixing tank 1 and then introduced into a slurry bed reactor via a centrifugal pump 2. The mixture is heated to 65°C with stirring at 300 rpm. Subsequently, high-pressure isobutylene liquid, after depressurization, is introduced into the reaction system via an isobutylene mass flow meter 5 at a flow rate of 28 cubic meters per hour from the bottom of the slurry bed reactor through an aeration plate 15, initiating the alkylation reaction. Unreacted isobutylene gas is cooled by a condenser 6 and enters a gas storage tank 8 via an isobutylene rotor flow meter 7. When the gas storage tank 8 reaches 80% of its volume, a compressor 9 is activated to compress it into high-pressure isobutylene liquid for recycling. Finally, when the isobutylene rotor flow meter 7 displays a flow rate of 28 cubic meters per hour, it indicates that the alkylation reaction has been completed. The slurry bed reactor is stopped from heating. The completely reacted solid-liquid phase hydrocarbonation mixture is then centrifuged by the second centrifugal pump 12 and placed in the storage tank 10. After standing for 1 hour, the catalyst automatically settles to the bottom to achieve solid-liquid separation. The upper layer is the hydrocarbonation reaction product, which is then subjected to subsequent distillation separation. The bottom catalyst is regenerated and recycled.

[0052] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A process apparatus for the alkylation reaction of mixed cresols catalyzed by a solid acid, characterized in that, It includes a feeding unit, a reaction unit, and a product solid-liquid separation unit. The feeding unit includes a liquid-solid phase feeding unit and a gas phase feeding unit; The liquid-solid phase feeding unit includes a premix tank (1) and a first centrifugal pump (2); The gas phase feeding unit is the first steel cylinder (4); The reaction unit is a reactor (3); The product solid-liquid separation unit includes a second centrifugal pump (12) and a liquid storage tank (10); The outlet of the premix tank (1) is connected to the first centrifugal pump (2) and then to the lower part of the reactor (3); the outlet of the first gas cylinder (4) is connected to the reactor (3); the lower part of the reactor (3) is connected to the second centrifugal pump (12) and the liquid storage tank (10) in sequence.

2. The process apparatus for the solid acid catalytic alkylation reaction of mixed cresols according to claim 1, characterized in that, It also includes a gas recovery unit, which includes a condenser (6), a gas storage tank (8), a compressor (9), and a second gas cylinder (11) that are sequentially connected to the upper part of the reactor (3).

3. The process apparatus for the solid acid catalytic alkylation reaction of mixed cresols according to claim 2, characterized in that, It also includes an isobutylene mass flow meter (5), which is installed on the outlet of the first gas cylinder (4).

4. The process apparatus for the solid acid catalytic alkylation reaction of mixed cresols according to claim 3, characterized in that, It also includes an isobutylene rotor flow meter (7), which is installed on the pipeline between the outlet of the condenser (6) and the gas storage tank (8).

5. The process apparatus for the solid acid catalytic alkylation reaction of mixed cresols according to claim 4, characterized in that, The gas outlet of the first gas cylinder (4) extends into the reactor (3) from the bottom, and an aeration disc (15) is provided on the port.

6. The process apparatus for the solid acid catalytic alkylation reaction of mixed cresols according to claim 5, characterized in that, The reactor (3) is a batch-type slurry bed reactor, and a stirrer (13) is installed on the central axis of the reactor (3). Multiple layers of porous gas distributors (14) are horizontally spaced from bottom to top inside the reactor (3).

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