System and method for the hydrogenation of 1,4-butynediol to produce 1,4-butanediol and co-production of 1,4-butenediol

Abstract

This invention discloses a system and method for the hydrogenation of 1,4-butynediol to produce 1,4-butanediol and co-producing 1,4-butenediol. The system includes: a buffer tank, a first injector, a first hydrogenation reactor, a first magnetic capture separator, a first hydrocyclone separator, and a first filtration device, connected in sequence, for the production of 1,4-butenediol; the first hydrogenation reactor is connected in sequence to a second hydrogenation reactor, a second magnetic capture separator, a second hydrocyclone separator, and a second filtration device, for the production of 1,4-butanediol; wherein, the catalyst outlet of the first magnetic capture separator is connected in sequence to the first injector and the first hydrogenation reactor; a second injector is also provided between the buffer tank and the first hydrogenation reactor; the catalyst outlet of the second magnetic capture separator is connected in sequence to the second injector and the first hydrogenation reactor. This invention achieves the co-production of 1,4-butenediol during the production of 1,4-butanediol, with continuous catalyst recycling, a short process, and simple operation.

Description

Technical Field

[0001] This invention relates to the field of 1,4-butanediol and 1,4-butenediol preparation technology, specifically to a system and method for producing 1,4-butanediol and co-producing 1,4-butenediol by hydrogenation of 1,4-butynediol. Background Technology

[0002] 1,4-Butanediol, obtained by the complete hydrogenation of 1,4-butynediol, is an important organic and fine chemical raw material widely used in pharmaceuticals, chemicals, textiles, papermaking, automobiles, and daily chemical products. It can be used to produce tetrahydrofuran (THF), polybutylene terephthalate (PBT), gamma-butyrolactone (GBL), polyurethane resins (PU Resin), coatings, plasticizers, and as a solvent and brightening agent in the electroplating industry.

[0003] 1,4-Butenediol is obtained by the semi-hydrogenation of 1,4-butynediol and is a raw material for the synthesis of 1,2,4-butanetriol. 1,2,4-Butanetriol trinitrate is an important component of high-energy nitrate ester plasticized polyether (NEPE) propellants and can also be used as a pharmaceutical raw material. Furthermore, 1,4-Butenediol, 1,2,4-butanetriol, and their derivatives (such as 2,3-epoxy-1,4-butanediol, γ-butyrolactone, tetrahydrofuran, vinylpyrrolidone, and PBT resin) are also important organic chemical intermediates with significant applications in polymer materials, pharmaceuticals, papermaking, tobacco, and electroplating industries. Therefore, selecting suitable catalysts and reaction conditions to improve the selectivity of the partially hydrogenated product 1,4-butenediol has significant theoretical importance and potential application value.

[0004] Currently, there are five main production methods for 1,4-butenediol: the 1,4-butynediol semi-hydrogenation method, the 1,4-dichloro-2-butene hydrolysis method, the 1,3-butadiene method, the 1,2-epoxy-3-butene method, and the 1,4-diacetoxybutane method. Among these, the 1,4-butynediol semi-hydrogenation method is the most widely used method for producing 1,4-butenediol.

[0005] CN206204184U discloses a system for the continuous production of butenyl glycol and co-production of butanediol via hydrogenation of butynediol. This system comprises a decolorization reaction system, a semi-hydrogenation reaction system, a butenyl glycol distillation system, a full hydrogenation reaction system, and a butanediol distillation system connected in sequence. The butynediol feedstock tank is connected to the decolorization reaction system, which is connected to the semi-hydrogenation reaction system. The semi-hydrogenation reaction system is connected to the butenyl glycol distillation system, which is connected to the full hydrogenation system, and the full hydrogenation system is connected to the butanediol distillation system. However, this system has a long process flow, numerous devices, does not involve catalyst recycling, has high catalyst consumption, and cannot maximize economic benefits. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of complex operation steps and low catalyst utilization in the prior art, and to provide a system and method for the hydrogenation of 1,4-butynediol to produce 1,4-butanediol and 1,4-butenediol. This system and method are flexible and easy to operate, and can almost realize the recovery and recycling of all catalysts.

[0007] To achieve the above objectives, the first aspect of the present invention provides a system for the hydrogenation of 1,4-butynediol to produce 1,4-butanediol and co-producing 1,4-butenediol, the system comprising: a buffer tank, a first injector, a first hydrogenation reactor, a first magnetic capture separator, a first hydrocyclone separator and a first filtration device connected in sequence, for the production of 1,4-butenediol;

[0008] The first hydrogenation reactor is also connected to a second hydrogenation reactor, which is in turn connected to a second magnetic capture separator, a second hydrocyclone separator, and a second filtration device for the production of 1,4-butanediol.

[0009] The catalyst outlet of the first magnetic capture separator is sequentially connected to the first injector and the first hydrogenation reactor; a second injector is also provided between the buffer tank and the first hydrogenation reactor; the catalyst outlet of the second magnetic capture separator is sequentially connected to the second injector and the first hydrogenation reactor; the bottom outlet of the first hydrocyclone separator and the bottom outlet of the second hydrocyclone separator are respectively connected to the buffer tank.

[0010] A second aspect of the present invention provides a method for the hydrogenation of 1,4-butynediol to produce 1,4-butanediol and concurrently 1,4-butenediol, using the aforementioned system, the method comprising:

[0011] An aqueous solution of 1,4-butynediol and optionally a fresh hydrogenation catalyst are fed into the first hydrogenation reactor via the first injector and the second injector. In the presence of the hydrogenation catalyst, a first hydrogenation reaction is carried out to obtain a first hydrogenation reaction product, wherein the conversion rate of 1,4-butynediol is above 95%.

[0012] The first hydrogenation reaction product is divided into part A and part B; part A is subjected to first magnetic separation by the first magnetic capture separator to obtain a first product phase and a first catalyst phase; the first product phase is subjected to first separation by the first hydrocyclone separator to obtain a first clear liquid and a first turbid liquid; then the first clear liquid is subjected to first filtration by the first filtration device to obtain a product containing 1,4-butenediol.

[0013] The B portion is subjected to a second hydrogenation reaction in a second hydrogenation reactor to obtain a second hydrogenation reaction product; the liquid phase of the second hydrogenation reaction product is subjected to a second magnetic separation in a second magnetic capture separator to obtain a second product phase and a second catalyst phase; the second product phase is subjected to a second separation in a second hydrocyclone separator to obtain a second clear liquid and a second turbid liquid; then the second clear liquid is subjected to a second filtration in a second filtration device to obtain a product containing 1,4-butanediol.

[0014] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0015] 1) The system and method of the present invention achieve the simultaneous production of 1,4-butanediol and 1,4-butenediol, with fewer processes, simple operation, optimized combination of benefits, continuous recycling of catalyst, improved catalyst utilization efficiency, and reduced catalyst consumption.

[0016] 2) This invention utilizes a magnetic capture separator and a hydrocyclone separator to separate the catalyst from the aqueous solution along their respective routes. The catalyst particles in the magnetic capture separator are subject to bundled movement, resulting in good fluidity and stable operation. Furthermore, the catalyst is washed with washing water in the magnetic capture separator, reducing the impact of reaction products on the series of reactions. This allows for continuous operation, convenient maintenance, and low cost.

[0017] 3) The hydrogenation effect of the present invention can be achieved by changing the amount of catalyst circulating, without the need to add or subtract fresh catalyst, thus having good operational flexibility and feedstock adaptability. Attached Figure Description

[0018] Figure 1 This is a process flow diagram of a method for producing 1,4-butynediol from 1,4-butanediol by hydrogenation and co-production of 1,4-butenediol according to one embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the structure of a magnetic capture separator provided in one embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the structure of an injector provided in one embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of the structure of a hydrocyclone separator provided in one embodiment of the present invention;

[0022] Figures 5a-5d This is a graph showing the relationship between the concentration of 1,4-butynediol hydrogenation product and reaction time under different temperature conditions provided by the present invention; wherein, Figure 5a The graph shows the relationship between the concentration of the hydrogenation product of 1,4-butynediol and reaction time at 70℃. Figure 5bThe graph shows the relationship between the concentration of the hydrogenation product of 1,4-butynediol and reaction time at 80℃. Figure 5c The graph shows the relationship between the concentration of the hydrogenation product of 1,4-butynediol and reaction time at 90℃. Figure 5d This is a graph showing the relationship between the concentration of the hydrogenation product of 1,4-butynediol and reaction time at 100℃; in the graph, ■─1,4-butynediol; ●─1,4-butenediol; ▲─hydroxybutyraldehyde; - Tert-butyl acetoacetate; ─1,4-Butanediol; ★─n-Butanol;

[0023] Figures 6a-6d This is a graph showing the relationship between the concentration of 1,4-butynediol hydrogenation product and reaction time under different hydrogen pressure conditions provided by the present invention; wherein, Figure 6a The graph shows the relationship between the concentration of the hydrogenation product of 1,4-butynediol and reaction time under 3 MPa conditions. Figure 6b The graph shows the relationship between the concentration of the hydrogenation product of 1,4-butynediol and reaction time under 4 MPa conditions. Figure 6c The graph shows the relationship between the concentration of the hydrogenation product of 1,4-butynediol and reaction time under 5 MPa conditions. Figure 6d This is a graph showing the relationship between the concentration of the hydrogenation product of 1,4-butynediol and reaction time under 6 MPa conditions; in the graph, ■─1,4-butynediol; ●─1,4-butenediol; ▲─hydroxybutyraldehyde; - Tert-butyl acetoacetate; ─1,4-Butanediol; ★─n-Butanol. Detailed Implementation

[0024] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0025] The first aspect of this invention provides a system for the hydrogenation of 1,4-butynediol to produce 1,4-butanediol and concurrently 1,4-butenediol, such as... Figure 1 As shown, the system includes: a buffer tank a, a first injector d1, a first hydrogenation reactor b1, a first magnetic capture separator c1, a first hydrocyclone separator e1, and a first filtration device f connected in sequence, for the production of 1,4-butenediol;

[0026] The first hydrogenation reactor b1 is connected in sequence to the second hydrogenation reactor b2, the second magnetic capture separator c2, the second hydrocyclone separator e2, and the second filtration device g, for the production of 1,4-butanediol;

[0027] The catalyst outlet of the first magnetic capture separator c1 is sequentially connected to the first injector d1 and the first hydrogenation reactor b1; a second injector d2 is also provided between the buffer tank a and the first hydrogenation reactor b1; the catalyst outlet of the second magnetic capture separator c2 is sequentially connected to the second injector d2 and the first hydrogenation reactor b1; the bottom outlet of the first hydrocyclone separator e1 and the bottom outlet of the second hydrocyclone separator e2 are respectively connected to the buffer tank a.

[0028] In this invention, the injector, magnetic capture separator, and hydrocyclone all operate continuously. The catalyst solid-liquid separation and circulation system, composed of the injector, magnetic capture separator, and hydrocyclone, serves two purposes: first, to perform solid-liquid separation of the hydrogenated 1,4-butanediol aqueous solution; and second, to achieve continuous catalyst recycling. In existing processes for hydrogenating 1,4-butynediol to 1,4-butanediol, the catalyst is mostly used in a single-pass or intermittent circulation manner. This results in either very low catalyst utilization or complex and costly recycling operations. This invention achieves continuous catalyst recycling, thereby improving catalyst utilization efficiency and reducing catalyst consumption.

[0029] The system of this invention combines a magnetic capture separator with an injector and other equipment, enabling continuous recycling of the catalyst in the hydrogenation of 1,4-butynediol to 1,4-butanediol. It features a short process, simple equipment, and continuous operation, avoiding the drawbacks of intermittent operation and pressure reduction / increase operation of catalyst capture and transportation.

[0030] This invention integrates magnetic capture, aggregation, and washing functions, reduces the magnetic field requirements, broadens the range of operating parameters, and is the first to be applied in the production of 1,4-butanediol.

[0031] In this invention, the buffer tank serves two purposes: first, to stabilize the flow rate of the feedstock 1,4-butynediol into the hydrogenation reactor; and second, to ensure uniform mixing of the feedstock 1,4-butynediol with the fresh hydrogenation catalyst when fresh catalyst replenishment is required. The hydrogenation reactor is used to realize the hydrogenation reaction of 1,4-butynediol.

[0032] The magnetic capture separator used in this invention uses an external magnetic field for liquid-solid separation. The magnetic field is generated by a magnetic induction coil that is looped around the outside of the device, which can separate the magnetically separable catalyst from the fluid.

[0033] In some embodiments of the present invention, such as Figure 2 As shown, the first magnetic capture separator c1 and the second magnetic capture separator c2 respectively include:

[0034] A vertical container 1 includes an upper cylinder 11 and a lower cylinder 12; the top of the upper cylinder 11 is provided with a clear liquid outlet N2 for discharging the clear liquid after the catalyst is separated; the side wall of the lower cylinder 12 is provided with a slurry inlet N7 for adding slurry containing the catalyst.

[0035] At least two electromagnetic coils 2 are respectively looped around the outside of the upper cylinder 11 and arranged along the axial direction of the upper cylinder 11; and

[0036] The central tube 3 is located at the bottom of the lower cylinder 12 and extends into the interior of the lower cylinder 12; a washing water inlet N10 is provided at the bottom of the central tube 3; and a catalyst outlet N8 is also provided on the central tube 3 for discharging the separated catalyst.

[0037] The magnetic capture separator of the present invention comprises at least two Helmholtz coils, each independently connected to a transformer. The Helmholtz coils provide a magnetic field, which captures and aggregates the magnetic catalyst under the influence of the magnetic field. The catalyst then flows out of the central tube under gravity, and new catalyst continuously flows out of the central tube as the catalyst flows out.

[0038] In this invention, the effect of magnetic separation on solid catalyst particles comes from two aspects. Firstly, the presence of a magnetic medium, such as iron, allows for adsorption by a magnet. Preferably, the solid catalyst particles are larger than 100 mesh and have a significantly higher density than the liquid (i.e., a settling time of less than 20 seconds in a static liquid). Typical examples include industrial-grade Raney nickel and amorphous nickel particles. Secondly, the upward fluid velocity plays a role. Simultaneously, the density of the solid particles must be greater than that of the fluid, thus the solid naturally settles in a static fluid. When the upward flow velocity of the fluid exceeds the initial fluidization velocity of the bed, the bed expands, and the particles tend to fluidize. At this point, turning on the magnetic field immediately tightens the bed, requiring an even higher flow velocity to expand and fluidize again. Therefore, the magnetic field significantly increases the initial fluidization velocity of the bed, thereby increasing the processing air velocity and reducing equipment size. The magnetic capture separator of this invention can simultaneously perform capture, washing, and high-concentration slurry transport operations.

[0039] The magnetic capture separator used in this invention integrates magnetic capture and washing functions, while the ejector enables high-concentration slurry delivery under high pressure. The ejector can operate in high-pressure systems and at high slurry inlet concentrations, providing a slurry delivery method that regulates slurry flow rate and reduces the risk of solid blockage.

[0040] In this invention, the upper cylinder 11 and the lower cylinder 12 are connected by a flange 13.

[0041] In this invention, the washing water inlet N10 is located at the bottom of the central tube 3, which allows water to be introduced to wash away the reaction products adhering to the catalyst surface, thereby reducing the pollution of the reaction system during recycling.

[0042] In this invention, the catalyst is a magnetically separable catalyst, specifically a solid particle containing magnetic material. Preferably, the magnetic capture separator C of this invention can capture and recover fine catalyst particles, and preferably the catalyst particle size is greater than 100 mesh.

[0043] The magnetic capture separator of the present invention, such as Figure 2 As shown, it also includes pressure gauge mounting port K1, pressure gauge mounting port K3, and thermometer mounting port K2, as well as other auxiliary instrument ports.

[0044] In some embodiments of the present invention, the length-to-diameter ratio of the vertical container is 4-8:1, for example, 4:1, 5:1, 6:1, 7:1, 8:1, and any value within the range of any two values, preferably 5-6:1.

[0045] In some embodiments, the height Dk of the vertical container is 3-10m, preferably 5-7m.

[0046] In some embodiments of the present invention, the ratio of the length of the upper cylinder to the length of the lower cylinder is 5-9:1, for example, 5:1, 6:1, 7:1, 8:1, 9:1, and any value within the range of any two values, preferably 6-8:1.

[0047] In some embodiments of the present invention, the length-to-diameter ratio of the central tube is 4-12:1, for example, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, and any value within the range of any two values, preferably 6-10:1. The length-to-diameter ratio of the central tube must meet the washing requirements; if it is too short, the washing will not be sufficient; if it is too long, installation will be inconvenient.

[0048] In some embodiments of the present invention, the ratio of the diameter of the central tube to the diameter of the lower cylinder is 0.05-0.3:1, for example, 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, and any value within the range of any two values, preferably 0.1-0.25:1. If the ratio of the diameter of the central tube to the diameter of the lower cylinder is too large, the catalyst separation degree is low and the washing liquid volume is large; if the ratio of the diameter of the central tube to the diameter of the lower cylinder is too small, the catalyst is not easy to flow out from the central tube.

[0049] In some embodiments of the present invention, the diameter of the upper cylinder is the same as the diameter of the lower cylinder.

[0050] In some embodiments of the present invention, the upper opening of the central tube is higher than the slurry inlet.

[0051] In this invention, the length of the central tube must first meet the washing requirements. If the central tube is too short, washing will be insufficient; if the central tube is too long, installation will be inconvenient. If the slurry inlet is too high, the area below the slurry inlet will become a fluid dead zone, resulting in wasted space. Furthermore, for smaller central tubes (e.g., 25mm diameter), the flushing effect at the slurry inlet can prevent catalyst bridging at the central tube inlet, thus preventing the catalyst from exiting the central tube. For larger diameters (greater than 50mm), the flushing effect can be ignored.

[0052] In some preferred embodiments of the present invention, the upper opening of the central tube is 30-200 mm higher than the slurry inlet, for example, any value in the range of 30 mm, 50 mm, 80 mm, 100 mm, 120 mm, 150 mm, 180 mm, 200 mm, and any two of these values, preferably 50-150 mm higher.

[0053] In this invention, the bottom of the lower cylinder 12 is also provided with a catalyst discharge outlet N9, which is used to completely discharge the catalyst during shutdown and accident handling. The top of the upper cylinder 11 is also provided with a fresh catalyst replenishment port N1, and a fresh catalyst feeding pipeline is provided at the fresh catalyst replenishment port N1, which extends into the interior of the upper cylinder 11 for adding fresh catalyst.

[0054] In this invention, after the catalyst is discharged, fresh catalyst needs to be added to maintain the catalyst interface position in the magnetic separator. The catalyst in the magnetic separator can be maintained in quantity and activity through intermittent input and output, or through continuous input and output to maintain catalyst balance. Both methods require that fresh catalyst be added to the system promptly before the catalyst becomes deactivated; otherwise, the hydrogenation quality will not meet requirements. Simultaneously, a catalyst discharge line is arranged at the bottom of the magnetic separator for completely discharging the catalyst from the magnetic separator when necessary, typically used during shutdowns and accident handling.

[0055] In some embodiments of the present invention, the magnetic capture separator comprises 2-16 electromagnetic coils, for example, any value within the range of 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, or any two of these values, preferably 4-10 electromagnetic coils. Adjacent groups of electromagnetic coils are of the same size, and the magnetic field strength can be adjusted according to the actual separation situation.

[0056] In this invention, the current and voltage of the electromagnetic coils are supplied by two cabinets respectively. Each group consists of 2-4 electromagnetic coils and one cabinet. The voltage is adjusted between 50V and 200V, and the current is controlled by adjusting the voltage to keep the current constant at 10-14A.

[0057] In this invention, the basic structure of the magnetic capture separator is as follows: Figure 2 As shown, 2-16 Holmes magnetic induction coils are looped around a cylindrical container with a high aspect ratio. The size of the magnetic capture separator can be designed according to the amount of hydrogenation catalyst in the hydrogenation reactor, and the volume of the magnetic capture separator is approximately 1-2 times the volume required for the amount of hydrogenation catalyst in the hydrogenation reactor.

[0058] In some embodiments of the present invention, the interval between two adjacent sets of electromagnetic coils is 0.5-5m, for example, 0.5m, 1m, 2m, 3m, 4m, 5m, and any value in the range of any two values, preferably 1-4m.

[0059] In some embodiments of the present invention, the height Db of each set of electromagnetic coils is 0.1-1m, for example, 0.1m, 0.2m, 0.3m, 0.4m, 0.5m, 0.6m, 0.7m, 0.8m, 0.9m, 1m, and any value within the range of any two values, preferably 0.4-0.8m.

[0060] In some embodiments of the present invention, the inner diameter of each set of electromagnetic coils is 0.5-3m, for example, 0.5m, 0.8m, 1m, 1.5m, 2m, 2.5m, 3m, or any value within the range of any two values; the outer diameter is 1.0-4m, for example, 1m, 1.5m, 2m, 2.5m, 3m, 3.5m, 4m, or any value within the range of any two values.

[0061] In some embodiments of the present invention, each set of electromagnetic coils 2 is provided with a water inlet N3a and a water outlet N3b to reduce the temperature of the electromagnetic coils so as to ensure that the operating temperature of the electromagnetic coils is 40-70°C.

[0062] In this invention, water is introduced into the inlet of each electromagnetic coil and discharged from the outlet to cool the electromagnetic coil and dissipate the heat generated by the electromagnetic coil in a timely manner.

[0063] In this invention, a thermocouple is embedded in the middle of the electromagnetic coil to detect the temperature rise. The electromagnetic coil is cooled according to the temperature rise. Forced water cooling can be used, with cooling water entering from N3a and exiting from N3b after heat extraction.

[0064] In this invention, the magnetic capture separator C further includes a current sensor for monitoring the current in each electromagnetic coil. A current alarm is mounted on the current sensor, and the current alarm is set to a value of 6A-10A.

[0065] In this invention, when a low current alarm is triggered, to prevent the catalyst inside the magnetic capture separator from being carried out due to demagnetization, an interlock action is activated to shut off the valve and stop the discharge. The cause of the low current is quickly identified, the fault is promptly eliminated, and normal operation is restored.

[0066] In some embodiments of the invention, the magnetic capture separator C further includes a current sensor for monitoring the current in each electromagnetic coil.

[0067] In some embodiments of the present invention, a current alarm is provided on the current sensor, and the current alarm is set to 6A-10A.

[0068] In this invention, when a low current alarm is triggered, to prevent the catalyst in the magnetic capture separator C from being carried out due to demagnetization, an interlock action is activated to shut off the valve and stop the discharge. The cause of the low current is quickly identified, the fault is promptly eliminated, and normal operation is restored.

[0069] The working fluid used in the injector of this invention is derived from an aqueous solution of 1,4-butynediol, and the pressure only needs to meet the operating requirements of the injector. The injector of this invention is a hydraulic injector, vertically installed in the gas phase space at the top of the hydrogenation reactor. After the working fluid and catalyst slurry are mixed in the mixing chamber, they are directly fed into the hydrogenation reactor. The basic structure of the injector is as follows: Figure 3 As shown. Utilizing the principle of kinetic-static energy conversion in a Venturi tube, when a high-pressure working fluid is injected through the nozzle, its kinetic energy increases and its pressure energy decreases, creating a relatively low-pressure zone (mixing chamber). This zone introduces the liquid to be absorbed, which is then mixed and fed into a narrowing pipe section. The pipe diameter gradually increases, the flow velocity gradually decreases, and the pressure gradually increases, thus achieving the transport of a high-concentration solid slurry. The working fluid originates from a 1,4-butynediol aqueous solution, while the absorbed slurry is from the magnetic capture separator. Due to the pressure difference between the mixing chamber and the magnetic capture separator, the high-concentration slurry is "drawn in" by the low-pressure zone. By controlling the flow rate of the working fluid, this pressure difference can be controlled, thereby adjusting the flow rate of the "drawn in" slurry and controlling the slurry transport, thus controlling the catalyst concentration in the reactor.

[0070] In some embodiments of the present invention, such as Figure 1 and Figure 3As shown, the first feed inlet of the first injector d1 is located at the top of the first injector d1 and is connected to the buffer tank a; the second feed inlet of the first injector d1 is located at the upper part of the first injector d1 and is connected to the first magnetic capture separator c1; the second feed inlet of the first injector d1 is perpendicular to the first feed inlet of the first injector d1; the discharge outlet of the first injector d1 is located at the bottom of the first injector d1 and is connected to the first hydrogenation reactor b1.

[0071] In some embodiments of the present invention, the first inlet of the second injector d2 is located at the top of the second injector d2 and communicates with the buffer tank a; the second inlet of the second injector d2 is located at the upper part of the second injector d2 and communicates with the second magnetic capture separator c2; the second inlet of the second injector d2 is perpendicular to the first inlet of the second injector d2; the outlet of the second injector d2 is located at the bottom of the second injector d2 and communicates with the first hydrogenation reactor b1.

[0072] In this invention, the flow rate out of the injector = the catalyst flow rate entering the injector from the magnetic separator + the working fluid flow rate of the injector.

[0073] This invention utilizes an ejector under conditions of high slurry inlet concentration and pressure, featuring a method for regulating slurry flow rate and an anti-clogging mechanism and structural design for the ejector. The ejector of this invention functions as both a slurry flow rate regulator and a catalyst concentration regulator in the reaction system. By employing the ejector, high-concentration, high-inlet-pressure slurry transport is achieved, reducing the number of equipment and the process flow. This invention combines the ejector with a magnetic capture separator, representing the essence of solid capture, solid-liquid transport, control, and reaction concentration control.

[0074] Considering the equipment installation, the parts of the ejector that might require casting are placed inside the reactor, sharing the same pressure as the reaction system, thus not functioning as a pressure vessel. The parts extending out of the reactor are all machined, and their construction and manufacturing according to pressure vessel specifications present no difficulties.

[0075] The hydrogenation reactor used in this invention is designed to maintain a uniform dispersion of catalyst particles smaller than 50 micrometers, while ensuring that the gas retention rate in the liquid is maintained between 5-10%. The hydrogenation reactor can be selected from stirred tank or straight-tube slurry bed types. The gas-liquid separation residence time in the reactor is approximately 15-30 minutes. The reactor is equipped with a propeller-type agitator, and the agitator uses a magnetic seal or mechanical seal. An aqueous solution of 1,4-butynediol is used as the coolant or sealing fluid. The stirring effect is enhanced by installing four baffles along the inner wall of the stirred tank.

[0076] In some embodiments of the present invention, the first hydrogenation reactor b1 and the second hydrogenation reactor b2 are slurry bed reactors, respectively.

[0077] In this invention, the first and second hydrogenation reactors must be able to keep the catalyst particles in suspension while maintaining the gas retention rate in the liquid between 5-10%, and can be any slurry bed reactor. The number of hydrogenation reactors is two or more connected in series, preferably two to four.

[0078] For the production of 1,4-butanediol, the tandem process can select a reactant concentration distribution that results in a higher reaction rate and a smaller equipment volume. For the production of 1,4-butenediol as a secondary product, the tandem process can extract the intermediate product in a reactor with the highest concentration of 1,4-butenediol and a lower concentration of byproducts, thus obtaining corresponding benefits.

[0079] In some embodiments of the present invention, the first hydrogenation reactor b1 and the second hydrogenation reactor b2 are respectively provided with a hydrogen inlet and a post-reaction gas outlet.

[0080] The hydrocyclone separator of this invention is located after the magnetic capture separator. The 1,4-butanediol aqueous solution exiting from the top of the magnetic capture separator enters the hydrocyclone separator. A small amount of solid particles entering the hydrocyclone separator are concentrated again at its bottom and flow out in slurry form, continuously flowing to the reaction feed buffer tank, and then being pumped back to the reaction system for recycling via a raw material feed pump. The hydrocyclone separator used in this invention is a device of hydrocyclone separation technology. Based on the hydrocyclone theory of fluid mechanics, it employs guiding, diversion, and eddy suppression techniques, using a liquid as the carrier medium. The suspension is tangentially input into the hydrocyclone chamber under high pressure. Based on the difference in specific gravity and particle size, the particles and liquid are separated through swirling flow. The structure of the hydrocyclone separator is as follows... Figure 4 As shown, the equipment has an inlet D1, a clarified liquid outlet D2, and a mixed slurry outlet D3. According to the design, it can separate solid particles of 1-120μm, with an inlet slurry concentration ≤30wt% and a throughput range of 10-20m³. 3 / h, corresponding to an inlet and outlet pressure difference of 0.2-0.5MPa. When the throughput is 15m³ / h. 3 At a rate of / h, the pressure difference is approximately 0.45 MPa. The turbid liquid discharged from the bottom of the hydrocyclone separator has a catalyst content related to the feed catalyst concentration level, approximately 0-20 wt%, while the catalyst content of the clear liquid is <6 ppmwt (referring to catalyst particle size of 80-120 mesh). According to measurements, when the bottom pore size is... At that time, its turbidity flow rate remained constant within the operating range, approximately 2-3.5 L / min.

[0081] In some embodiments of the present invention, a catalyst outlet is also provided on the connecting pipe between the bottom outlet of the first hydrocyclone e1 and the buffer tank a, for intermittent or continuous removal of low-activity catalyst.

[0082] In some embodiments of the present invention, a catalyst outlet is also provided on the connecting pipe between the bottom outlet of the second hydrocyclone e2 and the buffer tank a, for intermittent or continuous removal of low-activity catalyst.

[0083] In some embodiments of the present invention, the first magnetic capture separator c1 and the second magnetic capture separator c2 are also connected to the water tank h, respectively.

[0084] In some embodiments, the first hydrocyclone and / or the second hydrocyclone may be omitted, but the addition of a hydrocyclone can further improve the separation of the catalyst.

[0085] A second aspect of the present invention provides a method for the hydrogenation of 1,4-butynediol to produce 1,4-butanediol and concurrently 1,4-butenediol, employing the aforementioned system, such as... Figure 1 As shown, the method includes:

[0086] An aqueous solution of 1,4-butynediol and optionally a fresh hydrogenation catalyst are fed into the first hydrogenation reactor b1 via the first injector d1 and the second injector d2. In the presence of the hydrogenation catalyst, a first hydrogenation reaction is carried out to obtain a first hydrogenation reaction product, wherein the conversion rate of 1,4-butynediol is above 95%.

[0087] The first hydrogenation reaction product is divided into part A and part B; part A is subjected to first magnetic separation by the first magnetic capture separator c1 to obtain a first product phase and a first catalyst phase; the first product phase is subjected to first separation by the first hydrocyclone separator e1 to obtain a first clear liquid and a first turbid liquid; then the first clear liquid is subjected to first filtration by the first filtration device f to obtain a product containing 1,4-butenediol.

[0088] The B portion is subjected to a second hydrogenation reaction in the second hydrogenation reactor b2 to obtain a second hydrogenation reaction product; the liquid phase of the second hydrogenation reaction product is subjected to a second magnetic separation in the second magnetic capture separator c2 to obtain a second product phase and a second catalyst phase; the second product phase is subjected to a second separation in the second hydrocyclone separator e2 to obtain a second clear liquid and a second turbid liquid; then the second clear liquid is subjected to a second filtration in the second filtration device g to obtain a product containing 1,4-butanediol.

[0089] In this invention, the hydrogenation of 1,4-butynediol is a complex process. Its product distribution is related to catalyst type, operating conditions such as temperature, pressure, and reaction time, as well as the type of impurities. To obtain the kinetic parameters of the 1,4-butynediol hydrogenation process, amorphous Ni-Mo was used as the catalyst, and the changes in the concentration of each product over time during the 1,4-butynediol hydrogenation process at different temperatures and pressures were investigated. Figures 5a-5d The figure shows the relationship between the concentration of 1,4-butynediol hydrogenation product and reaction time under different temperature conditions. Figures 6a-6d The figure shows the relationship between the concentration of 1,4-butynediol hydrogenation products and reaction time under different hydrogen pressure conditions; in the figure, ■─1,4-butynediol; ●─1,4-butenediol; ▲─hydroxybutyraldehyde; - Tert-butyl acetoacetate; ─1,4-Butanediol; ★─n-Butanol. From Figures 5a-5d As shown in 6a-6d, under different temperatures and pressures, different products exhibit similar trends with increasing hydrogenation time: In the initial stage of the reaction, with increasing reaction time, the amount of the starting material 1,4-butynediol gradually decreases, and the converted 1,4-butynediol mainly forms 1,4-butenediol, accompanied by the formation of γ-hydroxybutyraldehyde and tert-butyl acetoacetate. With further increases in reaction time, when the conversion rate of 1,4-butynediol reaches 95%, 1,4-butanediol begins to form in addition to 1,4-butenediol, while the amount of n-butanol formed increases significantly. Notably, in the later stage of the reaction, as the reaction continues, the intermediate γ-hydroxybutyraldehyde can be converted to 1,4-butanediol.

[0090] The results show that, in the presence of 1,4-butynediol, 1,4-butenediol essentially cannot generate 1,4-butanediol and n-butanol; only some hydroxybutyraldehyde is generated. n-Butanol is primarily produced in the second hydrogenation step, i.e., the hydrogenation of 1,4-butenediol to 1,4-butanediol. Once all 1,4-butenediol is converted, the n-butanol content will no longer increase. Increasing the temperature in the later stages of the reaction allows for further hydrogenation of hydroxybutyraldehyde to 1,4-butanediol. Increasing the hydrogen pressure provides sufficient hydrogen concentration on the catalyst surface, reducing the formation of semi-hydrogenated polymers. Increasing the severity of the reaction is beneficial for the complete hydrogenation of intermediates such as 1,4-butenediol and hydroxybutyraldehyde, but it increases the n-butanol content, reducing the product yield and thus increasing feedstock consumption. Therefore, the basis for optimizing the process is to lower the initial reaction temperature in the first hydrogenation step to enhance gas-liquid mass transfer and reduce the catalyst dosage to increase the hydrogen concentration on the catalyst's active surface. The second-step hydrogenation reaction employs increased reaction temperature and hydrogen pressure to ensure sufficient hydrogen concentration on the catalyst surface, shortening the non-zero-order reaction stage in the later stages of the second-step hydrogenation reaction. Simultaneously, the increased temperature in the later stages allows for further hydrogenation of the byproduct hydroxybutyraldehyde to generate 1,4-butanediol. Specifically, a two-stage hydrogenation process can be adopted: the intermediate hydrogenation products from the first hydrogenation reactor (first-stage hydrogenation) are separated from the catalyst and then proceed to the second reactor (second-stage hydrogenation) and / or a third reactor for supplementary treatment.

[0091] As the above analysis shows, the method of this invention utilizes the fact that the hydrogenation of 1,4-butynediol to 1,4-butanediol is a series of reactions. The intermediate product, 1,4-butenediol, has a peak concentration at a specific point t0. By controlling the reaction parameters, at t0, the starting material 1,4-butynediol is nearly eliminated, while the final product 1,4-butanediol has not yet appeared. A two-stage reaction system was designed, controlling the first-stage reaction system at an appropriate t0 time to obtain materials with the highest and lowest 1,4-butenediol concentrations, reducing the difficulty of subsequent 1,4-butenediol purification. The inventors, through extensive research, discovered that t0 is related to many factors, including pressure, catalyst activity, 1,4-butynediol concentration, hydrogen distribution, hydrogen flow rate, and temperature. Different parameters result in different positions of t0: it may arrive before 1,4-butanediol appears, or it may arrive after 1,4-butanediol has already appeared. If t0 occurs too early, the concentration of 1,4-butynediol is too high, and the reaction is incomplete. If t0 occurs too late, a large amount of 1,4-butanediol has already been generated, increasing the difficulty of subsequent separation (the boiling point difference between 1,4-butynediol, 1,4-butanediol, and 1,4-butenediol is small, while 1,4-butenediol is in the middle; therefore, the ideal situation is only 1,4-butynediol and 1,4-butenediol), resulting in a decrease in the yield of 1,4-butenediol. While controlling the occurrence of t0, it is also necessary to avoid backmixing of materials containing 1,4-butanediol, which could contaminate the 1,4-butenediol material. Therefore, during solid-liquid separation of the material targeting 1,4-butanediol in the subsequent reaction system, the catalyst slurry must be washed to remove as much of the 1,4-butanediol component contained in the circulating catalyst as possible.

[0092] This invention utilizes the phenomenon of t0 (total oxygen demand) and focuses on controlling t0 to co-produce 1,4-butenediol during the production of 1,4-butanediol, and proposes a specific process route. An appropriate t0 position can reduce the difficulty of separating 1,4-butenediol and shorten the process flow. Simultaneously, the combined production method of this invention offers the advantage that all byproducts from 1,4-butenediol production can be incorporated into subsequent reactions of 1,4-butanediol, thereby eliminating the consumption of byproducts from 1,4-butenediol production.

[0093] In this invention, fresh hydrogenation catalyst can be added along with the raw materials through the fresh catalyst replenishment port of the buffer tank, or through the fresh catalyst replenishment port N1 of the magnetic capture separator, and then sent into the reactor through the injector.

[0094] The catalyst used in this invention has the characteristics of being magnetizable, fine-particle, high-density, and flowing with the reactants. A technical route integrating catalyst capture, catalyst washing, and catalyst transportation and recycling has been designed to achieve continuous operation.

[0095] High-concentration solid particle transport can damage the mechanical seals of pumps. The higher the concentration, the greater the chance of damage; the higher the pressure, the greater the damage. Typically, centrifugal pumps require the solid slurry concentration not to exceed 15%, with some exceptions allowing 25%, but operation is at or near atmospheric pressure. Therefore, existing technologies struggle to achieve solid-liquid transport under high concentration and high inlet pressure. Existing methods primarily employ continuous capture and intermittent release mechanisms. Some can achieve high-pressure capture, but release requires a return to low pressure. This invention achieves the capture, washing, and transport of high-concentration slurries (20-30%) under high pressure, while maintaining continuity in all unit operations.

[0096] This invention uses a catalyst containing magnetizable components as the hydrogenation catalyst, which is for single-use. The catalyst concentration in the slurry-bed reaction system is between 1% and 5%. The amount of deactivation depends on the reaction system; for this process, the total amount of deactivation and loss is generally considered to be 0.02 kg / ton of processing capacity. Continuous or intermittent replenishment of this loss can maintain constant hydrogenation efficiency. If the reaction effect is unsatisfactory, the amount of catalyst replenished needs to be increased, and a corresponding amount of recycled catalyst needs to be removed. Recycling the hydrogenation catalyst is more reasonable and economical than the traditional single-use approach.

[0097] In some embodiments of the present invention, the first catalyst phase is returned to the first hydrogenation reactor b1 via the first injector d1 for recycling.

[0098] In some embodiments of the present invention, the second catalyst phase is returned to the first hydrogenation reactor b1 via the second injector d2 for recycling.

[0099] In some embodiments of the present invention, during the first hydrogenation reaction, the amount of gas retained in the liquid is controlled to be maintained at 5-10 wt%, for example, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, and any value within the range of any two values.

[0100] In some embodiments of the present invention, during the first hydrogenation reaction, the concentration of the hydrogenation catalyst is controlled to be 1-5 wt%, for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, and any value within the range of any two values.

[0101] In some embodiments of the present invention, the hydrogenation catalyst is a solid particle containing magnetic material, preferably a nickel catalyst, an amorphous alloy catalyst with nickel as the main active component, or a supported catalyst with nickel and iron as the main active components; preferably, the particle size of the hydrogenation catalyst is greater than 100 mesh.

[0102] In some embodiments of the present invention, the flow ratio of part A to part B is 0.1-5, for example, 0.1wt%, 0.2wt%, 0.5wt%, 0.8wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, and any value within a range of any two values.

[0103] In some embodiments of the present invention, the conditions for the first hydrogenation reaction include: a temperature of 40-70°C, a pressure of 1-4 MPa, a pH of 7-10, and a time of 1-5 h.

[0104] In some embodiments of the present invention, the conditions for the second hydrogenation reaction include: a temperature of 40-70°C, a pressure of 1-4 MPa, a pH of 7-10, and a time of 2-6 h.

[0105] In this invention, an aqueous solution rich in 1,4-butenediol is drawn from the first hydrogenation reactor and, after passing through a magnetic capture separator, an ejector, and a hydrocyclone, the slurry is returned in whole or in part to the reaction system for recycling. The clarified liquid enters the subsequent 1,4-butenediol purification system for purification. Another aqueous solution drawn from the first hydrogenation reactor enters the second hydrogenation reactor for further reaction to obtain an aqueous solution of 1,4-butenediol. After passing through a magnetic capture separator, an ejector, and a hydrocyclone, the catalyst is separated from the solution. The separated catalyst is returned in whole or in part to the reaction system for recycling, while the 1,4-butenediol aqueous solution, which contains almost no catalyst, enters the downstream system. During the catalyst recycling process, used catalyst can be removed or fresh catalyst can be added, depending on the catalyst's activity level. The removal and addition of fresh catalyst can be instantaneous and continuous or intermittent and periodic.

[0106] In some embodiments of the present invention, the method further includes: introducing water into the first magnetic capture separator c1 and the second magnetic capture separator c2, respectively.

[0107] In some embodiments of the present invention, the method further includes: returning the first turbid liquid and the second turbid liquid to the buffer tank a.

[0108] In some embodiments of the present invention, the method further includes: subjecting the obtained product containing 1,4-butenediol to a first purification to obtain the 1,4-butenediol product.

[0109] In some embodiments of the present invention, the method further includes: subjecting the obtained product containing 1,4-butanediol to a second purification to obtain the 1,4-butanediol product.

[0110] According to a particularly preferred embodiment of the present invention, a method for the hydrogenation of 1,4-butynediol to produce 1,4-butanediol and 1,4-butenediol is provided, employing methods such as... Figure 1 The process flow diagram shown includes the following steps:

[0111] A 1,4-butynediol aqueous solution enters the reaction feed buffer tank a through the raw material pipeline, where various materials are dispersed and mixed. The prepared 1,4-butynediol aqueous solution is pumped into the first hydrogenation reactor b1. Hydrogen is sent to the two hydrogenation reactors through pipelines. A hydrogenation reaction is carried out in the first hydrogenation reactor b1, so that the reaction progress is exactly at the node where the concentration of 1,4-butenediol is high and the concentration of 1,4-butanediol is low.

[0112] The B portion, drawn from the first hydrogenation reactor, enters the second hydrogenation reactor b2 via pipeline for a two-stage hydrogenation reaction. The resulting 1,4-butanediol aqueous solution enters the second magnetic capture separator c2 via pipeline. Water from water tank h is washed in the second magnetic capture separator c2 to remove reaction products adhering to the catalyst surface. The gas after the reaction is discharged via pipeline for recycling (recycling method not specified). The catalyst and slurry enter the second injector d2 from the bottom of the magnetic capture separator and return to the first hydrogenation reactor under the action of the working fluid. The liquid at the top of the magnetic capture separator enters the second hydrocyclone separator e2 via pipeline. The clear liquid is sent to the second filtration device g via the top pipeline of the hydrocyclone separator, and after filtration, it is sent to the downstream unit via pipeline; the turbid liquid is returned to the reaction feed buffer tank a via pipeline.

[0113] Section A, drawn from the first hydrogenation reactor, is piped to the first magnetic capture separator c1. Water from water tank h is washed in the first magnetic capture separator c1 to remove reaction products adhering to the catalyst surface. The catalyst slurry enters the first injector d1 from the bottom of the magnetic capture separator and returns to the first hydrogenation reactor under the action of the working fluid. The liquid at the top of the magnetic capture separator enters the first hydrocyclone separator e1 through a pipeline. The clear liquid is sent to the first filter device f through a pipeline at the top of the hydrocyclone separator. After filtration, it is sent to the downstream 1,4-butenediol refining unit through a pipeline. The turbid liquid is returned to the reaction feed buffer tank a through a pipeline. Fresh catalyst can be replenished through the pipeline, and catalyst can also be withdrawn intermittently or continuously through the pipeline. The 1,4-butenediol reaction product after solid-liquid separation enters the 1,4-butenediol refining system through a pipeline.

[0114] The method for producing 1,4-butynediol and co-producing 1,4-butenediol by hydrogenation of 1,4-butynediol using catalyst recycling provided by the present invention specifically includes the following steps:

[0115] (1) The 1,4-butynediol aqueous solution from upstream is fed into the first hydrogenation reactor after being prepared. It comes into contact with hydrogen in the presence of a magnetizable solid particle hydrogenation catalyst. In the first hydrogenation reactor, the reaction is carried out under the following conditions: temperature 40-70℃, pressure 1-4MPa, residence time 1-5 hours, catalyst concentration 1-5wt%, and pH value alkaline. This ensures that the reaction progress is at the point where the concentration of 1,4-butenediol is high and the concentration of 1,4-butanediol is low. The output of the first hydrogenation reactor is divided into two parts: one part is sent to the second hydrogenation reactor according to the 1,4-butanediol process flow, and the other part is sent to the 1,4-butenediol magnetic capture separator.

[0116] (2) The material entering the second hydrogenation reactor continues the hydrogenation reaction under reaction conditions of 40-70℃, 1-4MPa, residence time of 2-6 hours, catalyst concentration of 1-5wt%, and alkaline pH. After the reaction, the 1,4-butanediol aqueous solution containing solid particulate catalyst enters the 1,4-butanediol magnetic capture separator. The magnetic capture separator separates the catalyst from the solution, making the 1,4-butanediol aqueous solution essentially free of solid catalyst. The catalyst concentrated in the magnetic capture separator is led out by a central pipe to the mixing chamber inlet of the 1,4-butanediol injector. The aqueous solution exiting from the top of the magnetic capture separator enters the hydrocyclone separator. The turbid liquid is collected at the bottom and flows continuously in slurry form to the reaction feed buffer tank. It is then pumped back to the reaction system for recycling. The solid content of the catalyst depends on the catalyst concentration of the reaction system, approximately 1-20 wt%. The clear liquid, a 1,4-butanediol aqueous solution after hydrogenation, is sent to the 1,4-butanediol filtration system. The filtered 1,4-butanediol aqueous solution is sent to downstream units. Both the magnetic capture separator and the hydrocyclone separator operate continuously.

[0117] (3) The material introduced into the 1,4-butenediol magnetic capture separator enters from the bottom and flows upward through the separator. The solid catalyst is captured and retained in the magnetic field, so that the 1,4-butenediol aqueous solution is basically free of solid catalyst, with a solid concentration of about 20-30 wt%. The catalyst is led out from a central pipe to the mixing chamber inlet of the 1,4-butenediol injector and carried into the reactor for recycling under the action of the working fluid. The 1,4-butenediol aqueous solution exiting from the top of the magnetic capture separator enters the hydrocyclone separator. A small amount of solid particles are concentrated at the bottom and flow continuously to the reaction feed buffer tank in the form of turbid liquid. It is then sent to the reaction system for recycling by the raw material feed pump. The liquid part is the 1,4-butenediol aqueous solution after hydrogenation reaction, which is sent to the 1,4-butenediol filtration system. The filtered 1,4-butenediol clear liquid is sent to the distillation and purification unit. A sampling port is provided on the discharge pipeline to check the concentration of catalyst carried out by the magnetic capture separator. Magnetic capture separators and hydrocyclones can operate continuously.

[0118] (4) After the deactivated catalyst is fed into the catalyst settling tank for solid-liquid separation, it is completely unloaded into a transport vehicle or a trench, thus completing the unloading of the catalyst solid particles from the catalyst settling tank. After the catalyst is unloaded, fresh catalyst needs to be fed in to maintain the interface position of the catalyst in the magnetic capture separator.

[0119] The raw material used in this invention is preferably an aqueous solution of 1,4-butynediol with a mass fraction of 25%-60 wt% and a pH value of 8-9. The lower the mass fraction of 1,4-butynediol, the higher the selectivity of 1,4-butanediol and the fewer byproducts generated. When the mass fraction of 1,4-butynediol is small, the byproduct n-butanol can be maintained at a low level. When the mass fraction of the raw material is greater than 30%, the selectivity of 1,4-butanediol decreases significantly. At the same time, alkaline conditions are conducive to the formation of 1,4-butanediol and the reduction of byproducts.

[0120] The reactor used in this invention is designed to keep catalyst particles smaller than 60 micrometers in suspension while maintaining a gas retention rate in the liquid between 5-10%. A hydrogenation stirred tank type is preferred. The gas-liquid separation residence time in the reactor is approximately 15-30 minutes. The reactor is equipped with a propeller-type agitator, and the agitator uses either a magnetic or mechanical seal. A 1,4-butynediol aqueous solution is used as the coolant or sealing fluid. Multiple baffles are installed along the inner wall of the stirred tank to enhance the stirring effect. Two or more hydrogenation reactors can be connected in series, preferably two to four in series.

[0121] The solid particulate hydrogenation catalyst used in this invention is a magnetizable catalyst with a certain particle size, suitable for unsaturated hydrogenation, and preferably an amorphous, highly active nickel catalyst for hydrogenation. To eliminate the influence of internal diffusion on reactant concentration and rate, the catalyst particles are selected with a particle size greater than 100 mesh. Preferably, the particle size of the hydrogenation catalyst is 5-150 μm, for example, 5 μm, 10 μm, 20 μm, 30 μm, 50 μm, 80 μm, 100 μm, 130 μm, 150 μm, or any value within the range of any two of these values, preferably 30-100 μm.

[0122] According to the process method provided by the present invention, the addition of fresh catalyst and the removal of used catalyst can be intermittent and periodic or instantaneous and continuous.

[0123] To ensure the reaction progress in the first hydrogenation reactor reaches the point where the concentrations of 1,4-butenediol are both high and low, appropriate reaction conditions need to be controlled. This can be achieved by controlling parameters such as reaction temperature, catalyst concentration, or H2 quantity within a given reaction space. The hydrogenation reaction temperature significantly affects the product yield and has a substantial impact on the formation of the byproduct n-butanol. Therefore, on an amorphous nickel catalyst, to reduce the formation of byproducts n-butanol and carbonyl compounds, the temperature should be controlled as low as possible below 40-70℃, ideally between 50-60℃, to obtain a higher selectivity for the target product, 1,4-butenediol, while ensuring complete conversion of 1,4-butynediol.

[0124] The reaction pressure of the first and second reactors is generally 1-4 MPa, preferably 1.5-3 MPa. Higher reaction pressure can accelerate the reaction rate and reduce the time to reach equilibrium, but higher pressure also means higher equipment investment.

[0125] The residence time of the reaction is related to the reaction temperature, reaction pressure, and catalyst concentration, and is generally 4-10 hours. To ensure complete reaction of 1,4-butenediol, the residence time in the second reactor is adjustable. The reaction time in the first hydrogenation reactor is fixed under certain throughput requirements, while the reaction time in the second hydrogenation reactor can be adjusted according to the liquid level control.

[0126] The magnetic capture separator described in steps (2) and (3) utilizes an external magnetic field for liquid-solid separation. Under a certain magnetic field strength, the catalyst can form a constrained, linked motion, exhibiting fluidity, generated by 2-16 Holmes magnetic induction coils encircling the device. The basic structure of the magnetic capture separator is as follows: Figure 1As shown, 2-16 Holmes magnetic induction coils are looped around a cylindrical container with a high aspect ratio. The size of the magnetic capture separator can be designed according to the amount of catalyst in the reactor, and its volume should be greater than or equal to the volume required for the amount of catalyst in the reactor. Generally, its height Dk is 3-10m, the height of each coil Db is 0.1-1m, and the interval between them is 0.5-5m.

[0127] In process description (2), the injector is a hydraulic injector, vertically installed in the gas phase space at the top of the first hydrogenation reactor. The working fluid and catalyst slurry are mixed in the mixing chamber and then directly fed into the reactor. The basic structure of the injector is as follows: Figure 2 As shown. Utilizing the principle of kinetic-static energy conversion in a Venturi tube, when a high-pressure working fluid is injected through the nozzle, its kinetic energy increases and its pressure energy decreases, creating a relatively low-pressure zone (mixing chamber). This zone introduces the liquid to be absorbed, which is then mixed and fed into a narrowing pipe section. The pipe diameter gradually increases, the flow velocity gradually decreases, and the pressure gradually increases, thus achieving the transport of a high-concentration solid slurry. The working fluid originates from a 1,4-butynediol aqueous solution, while the absorbed slurry is from the magnetic capture separator. Due to the pressure difference between the mixing chamber and the magnetic capture separator, the high-concentration slurry is "drawn in" by the low-pressure zone. By controlling the flow rate of the working fluid, this pressure difference can be controlled, thereby adjusting the flow rate of the "drawn in" slurry and controlling the slurry transport, thus controlling the catalyst concentration in the reactor.

[0128] The hydrocyclone separator described in process descriptions (2) and (3) is a type of hydrocyclone separation technology. Based on the hydrocyclone theory of fluid mechanics, it utilizes guiding, diversion, and eddy-elimination techniques, using liquid as the carrier medium. The suspension is tangentially fed into the hydrocyclone chamber under high pressure. Based on differences in specific gravity and particle size, the particles and liquid are separated through swirling flow. The hydrocyclone separator is as follows... Figure 3 As shown, the equipment has an inlet N1, a mixed slurry N2, and a clarified liquid outlet N3. According to the design, it can separate solid particles of 1-120μm, with an inlet slurry concentration ≤30wt% and a throughput range of 10-20m³. 3 / h, corresponding to an inlet and outlet pressure difference of 0.2-0.5MPa. When the throughput is 15m³ / h. 3 At a rate of / h, the pressure difference is approximately 0.45 MPa. The turbid liquid discharged from the bottom of the hydrocyclone separator has a catalyst content related to the feed catalyst concentration level, approximately 0-20 wt%, while the catalyst content of the clear liquid is <6 ppmwt (referring to catalyst particle size of 80-120 mesh). According to measurements, when the bottom pore size is... At that time, its turbidity flow rate remained constant within the operating range, approximately 2-3.5 L / min.

[0129] The magnetic capture separator, ejector, and hydrocyclone of this invention constitute a catalyst solid-liquid separation and circulation system. This system has two functions: first, to perform solid-liquid separation operations on the hydrogenated 1,4-butanediol and 1,4-butenediol aqueous solutions; and second, to achieve continuous recycling of the catalyst. In existing processes for hydrogenating 1,4-butynediol to 1,4-butanediol and 1,4-butenediol, the catalyst is mostly used in a single-pass or intermittent circulation manner. This results in either very low catalyst utilization or complex and costly recycling procedures. Therefore, continuous catalyst recycling is essential.

[0130] After passing through the magnetic capture separator, most of the catalyst has been separated, and only a small portion of the catalyst enters the hydrocyclone separator for further separation. Through the two-step separation of the magnetic separator and the hydrocyclone separator, almost all of the catalyst can be recovered and recycled.

[0131] According to the catalyst recycling method provided by this invention, the concentration of the catalyst in the reactor can be flexibly adjusted as needed. In principle, when the feedstock quality is poor or the hydrogenation effect needs to be improved, the catalyst concentration often needs to be increased; conversely, the catalyst concentration needs to be decreased. In existing 1,4-butanediol and 1,4-butenediol production processes, increasing the catalyst concentration can only be achieved by increasing the amount of fresh catalyst added. The catalyst is used only once, resulting in significant catalyst consumption. However, the method of this invention achieves this by changing the catalyst circulation rate, avoiding the problem of significantly increasing the amount of fresh catalyst used. Therefore, it has good operational flexibility and feedstock adaptability. The adjustment of the catalyst concentration needs to consider various factors such as feedstock quality, hydrogenation effect, catalyst performance, and the separation effect of magnetic separation and hydrocyclone separators. The catalyst concentration range is generally 1-5 wt%.

[0132] In the process description (4), maintaining the catalyst activity in the system is achieved by removing the catalyst in use and replenishing it with fresh catalyst.

[0133] The process for co-producing 1,4-butanediol from 1,4-butanediol provided by this invention can simultaneously produce 1,4-butanediol and achieve optimal efficiency.

[0134] All pressures in this invention are gauge pressures.

[0135] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited to the following description.

[0136] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0137] The catalysts used in the following examples are amorphous high-hydrogenation-activity nickel catalysts, and their specifications are shown in Table 1. Data for the magnetic capture separator is shown in Table 2, injector data in Table 3, hydrocyclone separator data in Table 4, magnetic separation design conditions in Table 5, and electromagnetic coil design conditions in Table 6.

[0138] Table 1 Specifications of Amorphous Catalysts

[0139]

[0140]

[0141] Table 2 Specifications of Magnetic Capture Separator

[0142] Da Db Dc Dd De Df Dg Dh Di 3320 680 400 200 150 800 300 700 1600 Dj Dk Dl Dm Dn Do Dp Dq 2800 5590 670 200 1000 2100 1200 100

[0143] Table 3 Injector Specifications

[0144] Da Db Dc Dd De Df Dg Dh 15.4 9.0 10 70 12 4.5 3.0 13 Di Dj Dk Dl Dm Dn Do 8 54 35 20 17.1 156.5 30.3

[0145] Table 4 Specifications of Hydrocyclone Separators

[0146] Da Db Dc Dd 1576 150 230 120

[0147] Table 5. Design conditions data for magnetic separators

[0148]

[0149] Table 6. Electromagnetic Coil Design Conditions Data

[0150] project Electromagnetic coil design conditions Operating temperature (ambient), °C 60 Operating cycle, h / a 7200 Magnetic field induction intensity, Gauss 600 Magnetic field voltage, V Adjustable, 380V rectified to 330V Current, A 12 Coil inner diameter, mm 1200 Coil outer diameter, mm 2100 Number of coils, 4 Height of each coil, mm 650 Coil mounting spacing, mm 300 electromagnetic coil material Copper Power, kW 3.2 Coil weight / piece, kg 44600 Connection method Four coils are connected in parallel, in pairs.

[0151] Example 1

[0152] This embodiment illustrates the effects of the magnetic capture separator, ejector, and hydrocyclone used in this invention on solid-liquid separation and the co-production of 1,4-butenediol.

[0153] use Figure 1The process flow diagram shown indicates that the purified 1,4-butynediol aqueous solution from the upstream unit, with a 1,4-butynediol concentration of 53.8 wt%, enters the reaction feed buffer tank a. In the buffer tank a, it is mixed with water and sodium hydroxide aqueous solution to prepare a reaction feedstock with a 1,4-butynediol concentration of 50 wt% and a pH of 8.5. The prepared raw materials were pumped into the first hydrogenation reactor b1. Under conditions of 55℃, 2MPa, and a catalyst concentration of 2wt%, the raw materials reacted with hydrogen. After 3 hours of reaction, a 35.47wt% crude 1,4-butenediol aqueous solution passed through a magnetic capture separator c1 and a hydrocyclone e1 before entering the subsequent purification system to obtain the 1,4-butenediol product. The catalyst was returned to the reaction system for recycling. The remaining 35.47wt% crude 1,4-butenediol aqueous solution (another portion of the liquid) from the first hydrogenation reactor b1 was sent to the second hydrogenation reactor b2 for reaction. After 3 hours of reaction, the crude 1,4-butenediol aqueous solution passed through a magnetic capture separator c2 and a hydrocyclone e2 before entering the subsequent purification system to obtain the 1,4-butenediol product. The catalyst was returned to the reaction system for recycling. The results are as follows:

[0154] (1) The concentrations of the 1,4-butanediol aqueous solution and the 1,4-butenediol aqueous solution catalyst exiting from the top of the magnetic capture separator were both 0.02 wt%, while the concentrations of the 1,4-butanediol aqueous solution catalyst exiting from the hydrocyclone were both 0.01 wt%. The results show that almost all the catalyst was separated from the 1,4-butanediol aqueous solution and the 1,4-butenediol aqueous solution after passing through the magnetic capture separator and the hydrocyclone.

[0155] (2) The concentration of crude 1,4-butanediol produced is 32.86 wt%, and the concentration of crude 1,4-butenediol produced is 35.47 wt%. All 1,4-butynediol reacts, realizing the continuous production of 1,4-butanediol while producing 1,4-butanediol. The process is simple and easy to operate.

[0156] Example 2

[0157] The method of Example 1 was used to produce 1,4-butanediol by hydrogenation, except that a hydrocyclone was not used. The concentration of hydrogenation catalyst in the 1,4-butanediol aqueous solution exiting from the top of the magnetic capture separator was 0.02 wt%. This shows that multiple separations using a magnetic separator and a hydrocyclone can further improve the separation degree of the catalyst.

[0158] Examples 3-9

[0159] Examples 3-9 illustrate the effect of reaction time on hydrogenation results according to the present invention.

[0160] The hydrogenation process for producing 1,4-butanediol was carried out according to the method in Example 1, with different reaction times. The results are shown in Table 7.

[0161] Table 7

[0162]

[0163]

[0164] As can be seen from Table 7, under certain conditions such as pressure, catalyst activity, 1,4-butynediol concentration, hydrogen distribution, hydrogen flow rate, and temperature, reasonable control of the reaction time can effectively increase the yield of 1,4-butenediol and improve the production efficiency of 1,4-butenediol.

[0165] Comparative Example 1

[0166] In the process of preparing butanediol using two-stage medium-pressure hydrogenation of butynediol in patent CN1040530C, most of the catalyst in the material after the first stage hydrogenation is separated by sedimentation and returned to the reactor. A small amount of catalyst is suspended in the reaction liquid and separated again by filtration through a catalyst filter. The filtered material is pumped into the second stage hydrogenation reactor by a high-pressure metering pump for reaction. The catalyst separation in the whole process is intermittent and the operation is complicated.

[0167] Comparative Example 2

[0168] Patent CN206204184U discloses a system for the hydrogenation of butynediol to produce butenediol and co-production of butanediol. This system includes a decolorization reaction system, a semi-hydrogenation reaction system, a butenediol distillation system, a full hydrogenation reaction system, and a butanediol distillation system connected in sequence. The butynediol feedstock tank is connected to the decolorization reaction system, which is connected to the semi-hydrogenation reaction system. The semi-hydrogenation reaction system is connected to the butenediol distillation system, which is connected to the full hydrogenation system, and the full hydrogenation system is connected to the butanediol distillation system. This system has a long process flow, numerous devices, does not involve catalyst recycling, has high catalyst consumption, and cannot maximize economic benefits. Furthermore, this system does not mention the key control parameters for co-production of butanediol.

[0169] The results above show that the embodiments of the present invention have significantly better effects, such as good selectivity, simple process, and high catalyst utilization.

[0170] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A system for the hydrogenation of 1,4-butynediol to produce 1,4-butanediol and concurrently 1,4-butenediol, characterized in that, The system comprises, in sequence, a buffer tank, a first injector, a first hydrogenation reactor, a first magnetic capture separator, a first hydrocyclone separator, and a first filtration device, for the production of 1,4-butenediol; The first hydrogenation reactor is connected in sequence to the second hydrogenation reactor, the second magnetic capture separator, the second hydrocyclone separator, and the second filtration device for the production of 1,4-butanediol; The catalyst outlet of the first magnetic capture separator is sequentially connected to the first injector and the first hydrogenation reactor; a second injector is also provided between the buffer tank and the first hydrogenation reactor; the catalyst outlet of the second magnetic capture separator is sequentially connected to the second injector and the first hydrogenation reactor; the bottom outlet of the first hydrocyclone separator and the bottom outlet of the second hydrocyclone separator are respectively connected to the buffer tank; The first magnetic capture separator and the second magnetic capture separator each include: A vertical container includes an upper cylinder and a lower cylinder; the top of the upper cylinder is provided with a clear liquid outlet for discharging the clear liquid after the catalyst is separated; the side wall of the lower cylinder is provided with a slurry inlet for adding slurry containing the catalyst. At least two electromagnetic coils are respectively looped around the outside of the upper cylinder and arranged along the axial direction of the upper cylinder; and A central tube is located at the bottom of the lower cylinder and extends into the interior of the lower cylinder; a washing water inlet is provided at the bottom of the central tube; a catalyst outlet is also provided on the central tube for discharging the separated catalyst.

2. The system according to claim 1, wherein, The length-to-diameter ratio of the vertical container is 4-8:1; And / or, the ratio of the length of the upper cylinder to the length of the lower cylinder is 5-9:1; And / or, the length-to-diameter ratio of the central tube is 4-12:1; And / or, the ratio of the diameter of the central tube to the diameter of the lower cylinder is 0.05-0.3:1; And / or, the diameter of the upper cylinder is the same as the diameter of the lower cylinder; And / or, the upper opening of the central tube is higher than the slurry inlet.

3. The system according to claim 2, wherein, The upper opening of the central tube is 30-200 mm higher than the slurry inlet.

4. The system according to claim 3, wherein, The upper opening of the central tube is 50-150 mm higher than the slurry inlet.

5. The system according to claim 1 or 2, wherein, The magnetic capture separator includes 2-16 electromagnetic coils.

6. The system according to claim 5, wherein, The interval between two adjacent sets of electromagnetic coils is 0.5-5m; And / or, the height Db of each set of electromagnetic coils is 0.1-1m.

7. The system according to claim 1 or 2, wherein, The first feed inlet of the first injector is located at the top of the first injector and is connected to the buffer tank; the second feed inlet of the first injector is located at the upper part of the first injector and is connected to the first magnetic capture separator; the second feed inlet of the first injector is perpendicular to the first feed inlet of the first injector; the discharge outlet of the first injector is located at the bottom of the first injector and is connected to the first hydrogenation reactor. And / or, the first inlet of the second injector is located at the top of the second injector and communicates with the buffer tank; the second inlet of the second injector is located at the upper part of the second injector and communicates with the second magnetic capture separator; the second inlet of the second injector is perpendicular to the first inlet of the second injector; the outlet of the second injector is located at the bottom of the second injector and communicates with the first hydrogenation reactor; And / or, the first hydrogenation reactor and the second hydrogenation reactor are slurry bed reactors, respectively.

8. A method for producing 1,4-butynediol by hydrogenation and concurrently producing 1,4-butenediol, characterized in that, The method, employing the system according to any one of claims 1-7, comprises: An aqueous solution of 1,4-butynediol is fed into the first hydrogenation reactor via the first injector and the second injector. In the presence of a hydrogenation catalyst, a first hydrogenation reaction is carried out to obtain the first hydrogenation reaction product, wherein the conversion rate of 1,4-butynediol is above 95%. The first hydrogenation reaction product is divided into part A and part B; part A is subjected to first magnetic separation by the first magnetic capture separator to obtain a first product phase and a first catalyst phase; the first product phase is subjected to first separation by the first hydrocyclone separator to obtain a first clear liquid and a first turbid liquid; then the first clear liquid is subjected to first filtration by the first filtration device to obtain a product containing 1,4-butenediol. The B portion is subjected to a second hydrogenation reaction in a second hydrogenation reactor to obtain a second hydrogenation reaction product; the liquid phase of the second hydrogenation reaction product is subjected to a second magnetic separation in a second magnetic capture separator to obtain a second product phase and a second catalyst phase; the second product phase is subjected to a second separation in a second hydrocyclone separator to obtain a second clear liquid and a second turbid liquid; then the second clear liquid is subjected to a second filtration in a second filtration device to obtain a product containing 1,4-butanediol.

9. The method according to claim 8, wherein, The first catalyst phase is returned to the first hydrogenation reactor via the first injector for recycling; And / or, the second catalyst phase is returned to the first hydrogenation reactor via the second injector for recycling.

10. The method according to claim 8 or 9, wherein, During the first hydrogenation reaction, the amount of gas retained in the liquid is controlled to be 5-10 wt%; And / or, during the first hydrogenation reaction, the concentration of the hydrogenation catalyst is controlled to be 1-5 wt%; And / or, the hydrogenation catalyst is a solid particle containing magnetic material.

11. The method according to claim 10, wherein, The hydrogenation catalyst is a nickel catalyst, an amorphous alloy catalyst with nickel as the main active component, or a supported catalyst with nickel and iron as the main active components. And / or, the particle size of the hydrogenation catalyst is greater than 100 mesh.

12. The method according to claim 8 or 9, wherein, The mass flow rate ratio of part A to part B is 0.1-5.

13. The method according to claim 8 or 9, wherein, The conditions for the first hydrogenation reaction include: a temperature of 40-70℃, a pressure of 1-4MPa, a pH of 7-10, and a time of 1-5h. And / or, the conditions for the second hydrogenation reaction include: a temperature of 40-70°C, a pressure of 1-4 MPa, a pH of 7-10, and a time of 2-6 h.

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