Methods and apparatus for restoring the activity of active metal catalysts

Abstract

This invention relates to the field of chemical production technology, specifically to a method and apparatus for restoring the activity of an active metal catalyst. The method includes: dissolving the active metal catalyst in an alkane solvent to obtain a catalyst with restored activity and a circulating solvent; dividing the circulating solvent into two streams for internal and external circulation; the internal circulation process includes: sequentially cooling and pressurizing the first stream of circulating solvent to obtain a pressurized solvent; the external circulation process includes: purifying the second stream of circulating solvent to obtain a purified solvent and a heavy stream; wherein the pressurized solvent and the purified solvent are independently returned for dissolution; the activity α of the restored catalyst satisfies formula I. This method not only improves the activity restoration of the active metal catalyst and extends the catalyst operating cycle, but also simplifies the process flow and facilitates industrial production.

Description

Technical Field

[0001] This invention relates to the field of chemical production technology, specifically to a method and apparatus for restoring the activity of an active metal catalyst. Background Technology

[0002] Active metal catalysts, such as alkali metal catalysts, have significant industrial application value in the propylene dimerization reaction. Industrial production of 4-methyl-1-pentene began abroad in the 1960s, using single alkali metal catalysts or mixtures of multiple alkali metals. Solid alkali catalysts, primarily using alkali metals as the active component, exhibit extremely high dimerization selectivity in the propylene dimerization reaction. Furthermore, through rational catalyst design, the selectivity of single dimerization products can be improved.

[0003] Since solid base catalysts in propylene dimerization typically contain alkali metals such as Na and K, which are highly sensitive to water and oxygen in the air, the loading and unloading of the catalyst is difficult and poses a high safety risk. Therefore, the longest possible catalyst operating cycle or service life is an important factor for the industrial reliability and efficiency of this technology.

[0004] Literature reports that when 4M1P is used as the target product in the propylene dimerization reaction, the thermodynamically optimal conditions are a temperature of 127-177℃ and a pressure of 10-15 MPa. Due to the relatively harsh reaction conditions (high pressure), as the reaction proceeds, the catalyst, especially supported metal catalysts, will deactivate due to the growth of active metal grains or central aggregates and the adsorption and coking of central colloidal matter. In actual propylene oligomerization processes, in addition to dimerization, oligomerization byproducts such as propylene trimers and tetramers, as well as high-molecular-weight polymers, are generated. These byproducts occupy the active sites of the catalyst, causing a decrease in catalyst activity. This reversible deactivation process can be addressed by regeneration to restore catalyst performance. In this case, if in-situ activity restoration measures are taken, the catalyst's operating time and service life can be extended. Therefore, in-situ activity restoration of deactivated or partially deactivated active metal catalysts is of practical significance for improving equipment efficiency, industrial reliability of this technology, and reducing the consumption of active metals.

[0005] CN106179489A discloses a method for regenerating a deactivated catalyst. The method involves first treating the deactivated catalyst with an organic solvent, then loading nickel onto the treated catalyst, followed by carbonization under oxygen-containing gas, and finally reducing the treated catalyst in a hydrogen atmosphere. The catalyst is then contacted with an olefinic acid solution containing chitosan in a vacuum or inert atmosphere, and finally dried and calcined to obtain a catalyst with restored activity. However, this activity restoration method requires oxidation or high-temperature carbonization, which can damage the catalyst structure, affect the interaction between the active metal and the support, and is complex to operate. Furthermore, it cannot regenerate the catalyst in situ, making it unsuitable for fixed-bed catalysts with active metals as the active component.

[0006] Therefore, developing a method for reactivating active metal catalysts is essential for processes using such catalysts, especially for the industrial application of propylene dimerization. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of low catalyst activity recovery, short operation cycle, high energy consumption, low safety, and complex process flow in existing methods for recovering the activity of active metal catalysts. This invention provides a method and an apparatus for recovering the activity of active metal catalysts. This method not only improves the activity recovery of active metal catalysts and extends the catalyst operation cycle, but also simplifies the process flow and facilitates industrial production.

[0008] The first aspect of this invention provides a method for restoring the activity of an active metal catalyst, the method comprising: dissolving the active metal catalyst in an alkane solvent to obtain an activity-restored catalyst and a circulating solvent; dividing the circulating solvent into two streams for internal and external circulation; the internal circulation process comprising: sequentially cooling and pressurizing the first stream of circulating solvent to obtain a pressurized solvent; the external circulation process comprising: purifying the second stream of circulating solvent to obtain a purified solvent and a heavy stream; wherein the pressurized solvent and the purified solvent are independently returned and dissolved separately.

[0009] Wherein, the activity α of the catalyst whose activity has been restored satisfies Equation I: δ represents the activity of the active metal catalyst; i is selected from positive numbers; The flow rate of the heavy material stream is expressed in kg / h and t. i The time for activity recovery, in hours;

[0010] In this invention, unless otherwise specified, the activity recovery process of converting an active metal catalyst into an activity-recovering catalyst is referred to as a single activity recovery process.

[0011] The inventors of this invention discovered that, based on the deactivation mechanism of active metal catalysts, alkane solvents are used to soak and dissolve the deactivated active metal catalysts. Specifically, utilizing the principle of "like dissolves like," the different solubilities of the components in the deactivated catalyst are physically separated by the alkane solvent, removing large molecular reaction byproducts from the catalyst, exposing the active sites, thereby extending the catalyst's operating cycle, reducing the number of catalyst loading and unloading operations, and lowering the safety risks associated with catalyst loading and unloading. Simultaneously, the recycled solvent obtained from the dissolution is divided into two streams for internal and external circulation. In particular, by controlling the circulation ratio of the internal and external circulation, the activity recovery and relative activity of the catalyst are more effectively improved.

[0012] A second aspect of the present invention provides an apparatus for restoring the activity of an active metal catalyst, the apparatus comprising: a reactor provided with a catalyst bed, and an alkane solvent delivery pipeline, an internal circulation pipeline and an external circulation pipeline connected to the reactor;

[0013] The active metal catalyst packed in the catalyst bed is dissolved with an alkane solvent to obtain an activity-restored catalyst and a circulating solvent. The circulating solvent is then divided into two streams, which enter the inner circulation pipeline and the outer circulation pipeline, respectively.

[0014] According to the material flow direction, a cooler and a pump are sequentially installed on the inner circulation pipeline to cool and pressurize the first stream of circulating solvent in sequence to obtain pressurized solvent; a fractionation tower is installed on the outer circulation pipeline to purify the second stream of circulating solvent to obtain purified solvent and heavy stream; the pressurized solvent and purified solvent are independently recycled to the reactor.

[0015] Through the above technical solution, this invention uses alkane solvents to restore the activity of active metal catalysts. Utilizing the principle of "like dissolves like," heavy substances are removed from the active metal catalyst, thereby increasing the number of active sites and improving the catalyst's activity and relative activity. Simultaneously, combined with Formula I, the flow rate of the heavy substance stream is controlled. By controlling the total time t for activity recovery, the activity α of the catalyst after activity recovery can be dynamically adjusted. In particular, by combining Equation II, the flow rate of the heavy stream in Equation I can be controlled by adjusting the flow rate ratio of the first and second circulating solvents (i.e., m / m'). This regulation shortens the total time for activity recovery.

[0016] Meanwhile, the method provided by this invention enables online activity recovery of active metal catalysts, extends the catalyst operation cycle, reduces the number of catalyst regeneration or unloading operations, and improves the efficiency of the equipment; the method also simplifies the process flow and facilitates industrial production applications. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the device for restoring the activity of an active metal catalyst provided by the present invention.

[0018] Explanation of reference numerals in the attached figures

[0019] 1. Reactor; 2. Cooler; 3. Pump; 4. Heater; 5. Distillation tower; 6. Alkane solvent delivery line; 7. External circulation line; 8. Internal circulation line; 9-i. First fresh solvent delivery line; 9-ii. Second fresh solvent delivery line;

[0020] 01. Alkane solvent; 02. Circulating solvent; 02-i. First circulating solvent; 02-ii. Second circulating solvent; 03. Solvent after pressurization; 04. Refined solvent; 05. Heavy stream; 06. Fresh alkane solvent; T. Temperature measurement point. Detailed Implementation

[0021] 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.

[0022] In this invention, unless otherwise specified, "first" and "second" do not indicate a sequence or limit the specific materials or steps. For example, "first" and "second" in "first stream of circulating solvent" are used only to indicate that these are not the same circulating solvent.

[0023] In this invention, unless otherwise specified, the “top” of the container refers to 0-10% of the container from top to bottom; the “upper part” of the container refers to 10-40% of the container from top to bottom; the “middle part” of the container refers to 40-60% of the container from top to bottom; the “lower part” of the container refers to 60-90% of the container from top to bottom; and the “bottom” of the container refers to 90-100% of the container from top to bottom.

[0024] The first aspect of this invention provides a method for restoring the activity of an active metal catalyst, the method comprising: dissolving the active metal catalyst in an alkane solvent to obtain an activity-restored catalyst and a circulating solvent; dividing the circulating solvent into two streams for internal and external circulation; the internal circulation process comprising: sequentially cooling and pressurizing the first stream of circulating solvent to obtain a pressurized solvent; the external circulation process comprising: purifying the second stream of circulating solvent to obtain a purified solvent and a heavy stream; wherein the pressurized solvent and the purified solvent are independently returned and dissolved separately.

[0025] Wherein, the activity α of the catalyst whose activity has been restored satisfies Equation I: δ represents the activity of the active metal catalyst; i is selected from positive numbers; The flow rate of the heavy material stream is expressed in kg / h and t. i The time for activity recovery, in hours;

[0026] In this invention, unless otherwise specified, the activity of the catalyst undergoing activity recovery is determined based on the flow rate of the heavy stream. This activity is further adjusted over the activity recovery time t. i Increase the flow rate of heavy materials. The activity α of the catalyst gradually recovers as the activity increases. Preferably, in Formula I, when the flow rate of the heavy stream... This indicates that the activity recovery of the active metal catalyst is complete.

[0027] In this invention, unless otherwise specified, f is a function relating the total amount of heavy material stream recovered by the catalyst with revitalized activity, obtained from experimental data. Preferably,

[0028] In this invention, unless otherwise specified, an active metal catalyst refers to a catalyst whose activity has decreased or deactivated, relative to a fresh active metal catalyst with 100% activity; that is, the activity δ of the active metal catalyst is less than 100%. Preferably, the activity δ of the active metal catalyst is ≤80%, and more preferably 20-80%.

[0029] In some embodiments of the present invention, preferably, the relative activity β of the activity-restored catalyst is ≥0.7, for example, 0.7, 0.8, 0.9, 1, 1.3, 1.5, 1.7, 2, 2.5, and any value in any range of any two values, preferably 0.7-2.5, and the relative activity β = (activity α of the activity-restored catalyst / activity δ of the active metal catalyst) - 1.

[0030] In this invention, in Formula I, the total activity recovery time includes not only the total dissolution time but also the total internal / external circulation time. Preferably, the total activity recovery time is selected from 6-66 hours, and more preferably 10-54 hours.

[0031] In this invention, the dissolution involves contacting and immersing an alkane solvent with an active metal catalyst to obtain a circulating solvent containing dissolved heavy material and a catalyst with restored activity. In this invention, the heavy material of the active metal catalyst is selected from macromolecular reaction byproducts, such as oligomerization byproducts like propylene trimers and tetramers.

[0032] In some embodiments of the present invention, preferably, the dissolution conditions include: a temperature of 25-350°C, preferably 25-200°C; a pressure of 0.5-11 MPa, preferably 0.5-5 MPa; and a single dissolution time of 1-20 h, preferably 4-15 h. In the present invention, all pressures refer to gauge pressure. In the present invention, the total dissolution time = the time of a single dissolution × the number of dissolutions.

[0033] In some embodiments of the present invention, preferably, the circulation ratio of the internal circulation and the external circulation is independently selected from 0-100, preferably 0-50; the circulation ratio refers to the volume ratio of the first circulating solvent and the second circulating solvent to the active metal catalyst, respectively.

[0034] In this invention, when the circulation ratio of the internal and external circulations is 0, it indicates that no circulating solvent is generated, meaning that the alkane solvent and the active metal catalyst are dissolved. When the circulation ratio of the internal and external circulations is not equal to 0, the circulating solvent is divided into a first circulating solvent and a second circulating solvent, which are circulated internally and externally respectively. In other words, dissolution and (internal and external circulations) belong to two different operating states. When dissolution occurs, both the internal and external circulations are shut down; or, when both internal and external circulations occur, dissolution is shut down. Furthermore, the internal and external circulations are linked operations, meaning they can occur simultaneously or be shut down simultaneously.

[0035] In some embodiments of the present invention, preferably, the dissolution is performed when the circulation ratio of the inner circulation and the outer circulation is both 0; and the inner circulation and the outer circulation are performed when the circulation ratio of the inner circulation and the outer circulation are both ≠ 0.

[0036] In some embodiments of the present invention, preferably, the number of times the circulation ratio is 0 during a single activity recovery process is selected from 1 to 5 times, wherein the single activity recovery process refers to the activity recovery process in which the active metal catalyst is transformed into the activity-recovering catalyst. In the present invention, when the circulation ratio of the inner circulation is 0 and the circulation ratio of the outer circulation is 0, it is recorded as 1 time the circulation ratio is 0. In the present invention, if the number of times the circulation ratio is 0 is greater than 1, it indicates that the number of times the circulation ratio of the inner circulation is 0 and the circulation ratio of the outer circulation is 0 is greater than 1.

[0037] In some embodiments of the present invention, preferably, during a single activity recovery process, the single cycle time when the circulation ratio is not equal to 0 is selected from 1-20 hours, and more preferably 4-15 hours. That is, when the circulation ratio of the inner circulation is not equal to 0 and the circulation ratio of the outer circulation is not equal to 0, the time of each cycle is selected from 1-20 hours, and more preferably 4-15 hours.

[0038] In this invention, by controlling the number of cycles with a ratio of 0 and the total time with a ratio of ≠ 0 (i.e., the total time with a ratio of ≠ 0 = the time of a single cycle with a ratio of ≠ 0 × the number of cycles with a ratio of ≠ 0), the activity recovery of the active metal catalyst can be effectively improved, thereby increasing the relative activity of the catalyst.

[0039] In some embodiments of the present invention, preferably, the process with a cycle ratio of 0 is set in the initial stage, the intermediate stage, and the final stage during a single activity recovery process.

[0040] In some embodiments of the present invention, preferably, the total time of the internal and external circulation during a single activity recovery process is 4-36 hours, more preferably 6-30 hours. In the present invention, the total time of the internal and external circulation includes the total time when the circulation ratio is not equal to 0.

[0041] In some embodiments of the present invention, preferably, during a single activity recovery process, the flow rate ratio of the first circulating solvent and the second circulating solvent satisfies Equation II: Where m and m' are the flow rates of the first and second circulating solvents, respectively, in kg / h; B is the circulation ratio of the internal circulation; N is the total number of times the operating condition with a circulation ratio of 0 occurs in a single activity recovery process; n' is the n'th time of the operating condition with a circulation ratio of 0 in a single activity recovery process, and n' is selected from a natural number from 1 to N.

[0042] In this invention, as activity recovery progresses, the flow rate of the heavy stream tends to increase first and then decrease. If the internal and external circulation flow rate ratio is not adjusted, the time required to separate the heavy stream increases, and the total activity recovery time also increases accordingly. Therefore, Equation II further defines the flow rate ratio of the first and second circulating solvents in the operating condition where the circulation ratio is 0 in the n'th cycle. This setting allows for faster adjustment of the heavy stream flow rate in Equation I by controlling the flow rate ratio of the first and second circulating solvents within the circulating solvent. This shortens the total time for activity recovery.

[0043] In this invention, unless otherwise specified, Right now, In Equation II, B is the circulation ratio of the inner loop.

[0044] In this invention, the internal circulation is intended to cool the first circulating solvent, and then pressurize the cooled solvent to obtain a pressurized solvent. Preferably, the temperature of the cooled solvent is 40-90°C, more preferably 40-80°C; the pressure of the pressurized solvent is 0.6-11 MPa, more preferably 0.6-5 MPa.

[0045] In this invention, the external circulation is intended to purify the second circulating solvent stream to obtain a heavy stream and a purified solvent. Preferably, the purification conditions include: a pressure of 1-5 MPa, more preferably 1-2.5 MPa, a reflux ratio of 1-3, and a theoretical plate number of 15-30.

[0046] In some embodiments of the present invention, preferably, the active metal in the active metal catalyst is selected from at least one metal element in the periodic table that has a reducing power stronger than hydrogen, preferably selected from at least one metal element in Group IA, Group IIA, Group IIIA, Group IVA, Group IIB and Group VIII, more preferably selected from at least one metal element in Na, K, Li, Rb, Cs, Mg, Al, Zn, Fe, Sn, Pb, Ni and Pd, and more preferably selected from Na and / or K.

[0047] In some embodiments of the present invention, preferably, the loading of the active metal in the active metal catalyst is 0.5-20 wt%, more preferably 3-10 wt%.

[0048] In one specific embodiment of the present invention, when the active metal in the active metal catalyst is selected from Na and K, the molar ratio of Na and K is not limited, as long as the total loading of Na and K meets the above-mentioned limitation.

[0049] In some embodiments of the present invention, preferably, the support for the active metal catalyst is selected from at least one of basic metal salts, inorganic metal oxides and molecular sieves, and more preferably, a basic metal salt; more preferably, the basic metal salt is selected from carbonates and / or acetates containing Na or K.

[0050] In this invention, a wide range of types of active metal catalysts can be selected. Preferably, the active metal catalyst is selected from catalysts used in the preparation of 4-methyl-1-pentene by propylene dimerization.

[0051] In some embodiments of the present invention, preferably, the alkane solvent is selected from C3-C8 alkanes; more preferably, the alkane solvent is selected from C3-C5 alkanes; more preferably, the alkane solvent is selected from at least one of propane, n-butane, isobutane, n-pentane and isopentane; most preferably, the alkane reagent is selected from propane and / or n-pentane.

[0052] In some embodiments of the present invention, preferably, the water content in the alkane solvent is ≤10ppmv, more preferably ≤3ppmv; and the oxygen content is ≤10ppmv, more preferably ≤3ppmv.

[0053] In some embodiments of the present invention, the presence of olefins in the alkane solvent reduces the selectivity of the solvent, and their content should be minimized. Preferably, the olefin content in the alkane solvent is ≤5% by volume, and more preferably ≤1% by volume.

[0054] In one specific embodiment of the present invention, the alkane solvent is selected from propane, and the water content in propane is ≤10 ppmv, preferably ≤3 ppmv; the oxygen content is ≤10 ppmv, preferably ≤3 ppmv; and the olefin content is ≤5% by volume, preferably ≤1% by volume.

[0055] In some embodiments of the present invention, preferably, the method further includes: mixing the pressurized solvent and the fresh alkane solvent and then performing the dissolution; more preferably, the mass flow rate ratio of the pressurized solvent and the fresh alkane solvent is 1000:0-1.

[0056] In some embodiments of the present invention, preferably, the method further includes: mixing the refined solvent and the fresh alkane solvent and then performing the dissolution; more preferably, the mass flow rate ratio of the refined solvent and the fresh alkane solvent is 1000:0-1.

[0057] In this invention, to further remove heavy substances from the active metal catalyst, preferably, the method further includes: heating the alkane solvent to 25-350°C, preferably 25-200°C, before the dissolution.

[0058] A second aspect of the present invention provides a schematic diagram of a device for restoring the activity of an active metal catalyst, as shown in the figure. Figure 1 As shown, by Figure 1 It is known that the device includes: a reactor 1 with a catalyst bed, and an alkane solvent delivery pipeline 6, an internal circulation pipeline 8 and an external circulation pipeline 7 connected to the reactor 1;

[0059] The active metal catalyst packed in the catalyst bed is dissolved with alkane solvent 01 to obtain an activity-restored catalyst and a circulating solvent 02. The circulating solvent 02 is then divided into two streams and enters the inner circulation pipeline 8 and the outer circulation pipeline 7, respectively.

[0060] According to the material flow direction, a cooler 2 and a pump 3 are sequentially installed on the inner circulation pipeline 8 to cool and pressurize the first stream of circulating solvent 02-i to obtain pressurized solvent 03; a fractionation tower 5 is installed on the outer circulation pipeline 7 to purify the second stream of circulating solvent 02-ii to obtain purified solvent 04 and heavy stream 05; the pressurized solvent 03 and purified solvent 04 are recycled to the reactor 1.

[0061] In this invention, unless otherwise specified, the inlet of the internal circulation pipeline 8 (i.e., the outlet of the first circulating solvent) can be connected to the reactor outlet, or it can be located inside the reactor and on the pipeline extending from the outlet. That is, the inlet of the internal circulation pipeline 8 is selected from 1 to 4 of the above-mentioned locations; the outlet of the internal circulation pipeline 8 (i.e., the inlet of the pressurized solvent) can be connected to the reactor inlet, or it can be located inside the reactor and on the pipeline extending from the inlet. That is, the outlet of the internal circulation pipeline 8 is selected from 1 to 4 of the above-mentioned locations.

[0062] Similarly, the inlet of the external circulation pipeline 7 (i.e., the outlet of the second circulating solvent) can be connected to the reactor outlet, or it can be located inside the reactor and on the pipeline extending from the outlet. That is, the inlet of the external circulation pipeline 7 is selected from 1 to 4 of the above-mentioned locations; the outlet of the external circulation pipeline 7 (i.e., the inlet of the purified solvent) can be connected to the reactor inlet, or it can be located inside the reactor and on the pipeline extending from the inlet. That is, the outlet of the external circulation pipeline 7 is selected from 1 to 4 of the above-mentioned locations.

[0063] In this invention, preferably, as follows: Figure 1 As shown, reactor 1 is selected from fixed-bed reactors.

[0064] In this invention, preferably, as follows: Figure 1 As shown, the apparatus further includes a heater 4 connecting the reactor 1 and the alkane solvent delivery pipeline 6, for heating the alkane solvent 01 to dissolve it.

[0065] In this invention, preferably, as follows: Figure 1 As shown, the device further includes a first fresh solvent delivery line 9-i connected to the internal circulation line 8, for mixing the pressurized solvent 03 and the fresh alkane solvent 06 and returning them to the reactor 1.

[0066] In this invention, preferably, as follows: Figure 1 As shown, the apparatus further includes a second fresh solvent delivery line 9-ii connected to the external circulation line 7, for mixing the refined solvent 04 and the fresh alkane solvent 06 and returning them to the reactor 1.

[0067] In this invention, preferably, as follows: Figure 1 As shown, the heater 4 is also connected to an internal circulation pipeline 8 and an external circulation pipeline 7, which are used to heat the pressurized solvent 03 and the refined solvent 04 respectively before they enter the reactor 1.

[0068] In this invention, preferably, as follows: Figure 1 As shown, the device further includes a temperature measuring point T connected to the top of the catalyst bed in the reactor 1, used to detect the temperature of the catalyst bed.

[0069] According to a particularly preferred embodiment of the present invention, a method for restoring the activity of an active metal catalyst includes: dissolving the active metal catalyst in an alkane solvent to obtain a catalyst with restored activity and a circulating solvent; dividing the circulating solvent into two streams for internal and external circulation; the internal circulation process includes: sequentially cooling and pressurizing the first stream of circulating solvent to obtain a pressurized solvent; the external circulation process includes: purifying the second stream of circulating solvent to obtain a purified solvent and a heavy stream; wherein the pressurized solvent and the purified solvent are independently returned and dissolved separately.

[0070] Wherein, the activity α of the catalyst whose activity has been restored satisfies Equation I: δ represents the activity of the active metal catalyst; i is selected from positive numbers; The flow rate of the heavy material stream is expressed in kg / h and t. i The time for activity recovery, in hours;

[0071] The circulation ratios of the internal and external circulations are each independently selected from 0 to 50. The circulation ratio refers to the volume ratio of the first and second circulating solvents to the active metal catalyst, respectively. In a single activity recovery process, the number of times the circulation ratio is 0 is selected from 1 to 5 times. The single activity recovery process refers to the activity recovery process in which the active metal catalyst is transformed into the activity recovery catalyst.

[0072] In a single activity recovery process, the flow rate ratio of the first circulating solvent and the second circulating solvent satisfies Equation II: Where m and m' are the flow rates of the first and second circulating solvents, respectively, in kg / h; B is the circulation ratio of the internal circulation; N is the total number of times the operating condition with a circulation ratio of 0 occurs in a single activity recovery process; n' is the n'th time of the operating condition with a circulation ratio of 0 in a single activity recovery process, and n' is selected from a natural number from 1 to N.

[0073] The present invention will be described in detail below through embodiments.

[0074] Example 1

[0075] Devices such as Figure 1 As shown, the device includes: a reactor 1 with a catalyst bed, an alkane solvent delivery pipeline 6, an internal circulation pipeline 8 and an external circulation pipeline 7 connecting the reactor 1, and a heater 4 connecting the alkane solvent delivery pipeline 6, the internal circulation pipeline 8, the external circulation pipeline 7 and the reactor 1.

[0076] According to the material flow direction, the internal circulation pipeline 8 is sequentially equipped with a cooler 2, a pump 3 and a first fresh solvent delivery pipeline 9-i, and the external circulation pipeline 7 is sequentially equipped with a fractionation tower 5 and a second fresh solvent delivery pipeline 9-ii; the upper part of the catalyst bed is connected to a temperature measuring point T;

[0077] The catalyst bed is filled with an active metal catalyst, with a loading amount of 25 kg and a bulk density of 0.991 g / mL.

[0078] The method is carried out in the above-described apparatus, and the method includes:

[0079] (1) The alkane solvent (propane, olefin content ≤1 vol%, water content ≤3 ppmv, oxygen content ≤3 ppmv) is heated to 50°C and dissolved with the above-mentioned active metal catalyst (activity δ is 30%, active components are selected from Na and K, the mass ratio of Na and K is 1:2, and the total loading is 5 wt%, the support is selected from potassium carbonate) first (temperature is 80°C, pressure is 4 MPa, single time is 4 h), and then internal and external circulation are carried out, and the circulating solvent is divided into the first circulating solvent and the second circulating solvent with a mass ratio of 16:1.

[0080] (2) The first circulating solvent is internally circulated, cooled to 50°C, and pressurized to 4MPa. The pressurized solvent and fresh propane are mixed at a mass flow rate ratio of 1000:0.1 and then heated for the above-mentioned dissolution. The second circulating solvent is externally circulated and fractionated (pressure 2MPa, reflux ratio 2, theoretical plate number 20) to obtain purified solvent and heavy stream. The purified solvent and fresh propane are mixed at a mass flow rate ratio of 1000:0.1 and then heated for the above-mentioned dissolution.

[0081] When the internal and external circulation times are 6 hours, adjust the circulation ratio to 0, close the internal and external circulation lines, and allow propane to dissolve in the catalyst bed for 4 hours. Then open the internal and external circulation lines, and repeat the internal and external circulation for another 6 hours. Then close the internal and external circulation lines, and so on, so that the operation condition with a circulation ratio of 0 is performed 4 times in a single activity recovery process.

[0082] After the first operation with a circulation ratio of 0 is completed, open the internal and external circulation lines according to Equation II: Adjust the flow rate ratio of the first circulating solvent to the second circulating solvent to 16:1. After the second cycle ratio operation is completed, open the internal and external circulation lines and adjust the flow ratio of the first and second circulating solvents to 8:1. After the third cycle ratio operation is completed, open the internal and external circulation lines and adjust the mass ratio of the first and second circulating solvent streams to 16:3. After the fourth cycle at a ratio of 0, open the internal and external circulation lines and adjust the mass ratio of the first and second circulating solvent streams to 4:1. Catalyst S1 with restored activity was obtained.

[0083] Example 2

[0084] According to the apparatus of Example 1,

[0085] The method is the same as in Example 1, except that the time for a single dissolution is adjusted to 12 hours, and the time for each internal and external circulation cycle is adjusted to 8 hours; that is,

[0086] When the internal and external circulation times are 8 hours, adjust the circulation ratio to 0, close the internal and external circulation pipelines, and allow propane to dissolve in the catalyst bed for 12 hours. Then open the internal and external circulation pipelines and circulate for another 8 hours. Then close the internal and external circulation pipelines. The operation condition with a circulation ratio of 0 is completed twice in one activity recovery process.

[0087] After the first operation with a circulation ratio of 0 is completed, open the internal circulation line and the external circulation line, and adjust the mass ratio of the first circulating solvent to the second circulating solvent to 8:1; after the second operation with a circulation ratio of 0 is completed, open the internal circulation line and the external circulation line, and adjust the mass ratio of the first circulating solvent to the second circulating solvent to 4:1.

[0088] Under the same conditions, catalyst S2 with restored activity was obtained.

[0089] Example 3

[0090] According to the apparatus of Example 1,

[0091] The method is the same as in Example 1, except that the alkane solvent is replaced with n-pentane (olefin content ≤ 1 vol%, water content ≤ 3 ppmv, oxygen content ≤ 3 ppmv).

[0092] Under the same conditions, catalyst S3 with restored activity was obtained.

[0093] Example 4

[0094] According to the apparatus of Example 1,

[0095] The method is the same as in Example 1, except that the mass ratio of the first circulating solvent to the second circulating solvent is maintained at 16:1 throughout the entire activity recovery process.

[0096] Under the same conditions, catalyst S4 with restored activity was obtained.

[0097] Example 5

[0098] According to the apparatus of Example 1,

[0099] The method is the same as in Example 1, except that...

[0100] In step (1), the activity δ of the active metal catalyst is replaced with 10%.

[0101] Under the same conditions, catalyst S5 with restored activity was obtained.

[0102] Comparative Example 1

[0103] The apparatus according to Example 1 differs in that it does not contain the external circulation pipe 7, the fractionation tower 5, and the second fresh solvent delivery line 9-ii;

[0104] According to the method of Embodiment 1, the method is carried out in the above-described apparatus, that is,

[0105] In step (2), the above-mentioned circulating solvent is internally circulated, cooled to 50°C and pressurized to 4MPa in sequence. The pressurized solvent is mixed with fresh propane and then heated to dissolve as described above, thereby obtaining the active catalyst DS1.

[0106] Comparative Example 2

[0107] The apparatus according to Embodiment 1 differs in that it does not contain the internal circulation line 8, the cooler 2, the pump 3, and the first fresh solvent delivery line 9-i;

[0108] According to the method of Embodiment 1, the method is carried out in the above-described apparatus, that is,

[0109] In step (2), the above-mentioned circulating solvent is externally circulated and fractionated (pressure 2MPa, reflux ratio 2, theoretical plate number 20) to obtain refined solvent and heavy stream. The refined solvent and fresh propane are mixed and then dissolved by heating to obtain the catalyst DS2 with restored activity.

[0110] Table 1

[0111]

[0112] Note: In this invention, Right now,

[0113] Continued from Table 1

[0114]

[0115]

[0116] As can be seen from the results in Table 1, compared with Comparative Examples 1-2, the method provided by this invention can effectively improve the activity of active metal catalysts, thereby effectively improving the activity recovery degree of active metal catalysts.

[0117] Meanwhile, compared to Example 4, Example 1 more effectively improves the degree of catalyst activity recovery by adjusting the internal and external circulation ratio of alkane solvent after each dissolution.

[0118] 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 method for restoring the activity of an active metal catalyst, characterized in that, The method includes: dissolving an active metal catalyst using an alkane solvent to obtain an activated catalyst and a circulating solvent; dividing the circulating solvent into two streams for internal and external circulation, respectively; the internal circulation process includes: sequentially cooling and pressurizing the first stream of circulating solvent to obtain a pressurized solvent; the external circulation process includes: purifying the second stream of circulating solvent to obtain a purified solvent and a heavy stream; wherein the pressurized solvent and the purified solvent are independently returned for the dissolution process. Wherein, the activity α of the catalyst whose activity has been restored satisfies Equation I: ， δ represents the activity of the active metal catalyst; i is selected as a positive number; φ i The flow rate of the heavy material stream is expressed in kg / h and t. i The time for activity recovery, in hours; ≥20%; In a single activity recovery process, the flow rate ratio of the first circulating solvent and the second circulating solvent satisfies Equation II: Where m and m' are the flow rates of the first and second circulating solvents, respectively, in kg / h; B is the circulation ratio of the internal circulation; N is the total number of times the circulation ratio is 0 in a single activity recovery process; n' is the n'th time of the circulation ratio is 0 in a single activity recovery process, and n' is selected from a natural number from 1 to N; the circulation ratio refers to the volume ratio of the first and second circulating solvents to the active metal catalyst, respectively; the single activity recovery process refers to the activity recovery process in which the active metal catalyst is transformed into the activity recovery catalyst.

2. The method according to claim 1, wherein, In formula I, when φ i =0 kg / h indicates that the activity recovery of the active metal catalyst is complete; And / or, in Formula I, the activity δ of the active metal catalyst is ≤80%; the total activity recovery time is selected from 6-66 h; =20-50%; And / or, the relative activity β of the activity-restored catalyst is ≥0.7, and the relative activity β = (the activity α of the activity-restored catalyst / the activity δ of the active metal catalyst) - 1.

3. The method according to claim 2, wherein, In Formula I, the activity δ of the active metal catalyst is 20-80%; the total activity recovery time is selected from 10-54 h. And / or, the relative activity β of the activity-restored catalyst is 0.7-2.5, and the relative activity β = (the activity α of the activity-restored catalyst / the activity δ of the active metal catalyst) - 1.

4. The method according to claim 1, wherein, The dissolution conditions include: temperature of 25-350℃; pressure of 0.5-11MPa; and single-time duration of 1-20h. And / or, the temperature of the solvent after cooling is 40-90°C; And / or, the pressure of the pressurized solvent is 0.6-11 MPa; And / or, the refining conditions include: a pressure of 1-5 MPa, a reflux ratio of 1-3, and a theoretical plate number of 15-30.

5. The method according to claim 4, wherein, The dissolution conditions include: temperature of 25-200℃; pressure of 0.5-5MPa; and single-time duration of 4-15 hours. And / or, the temperature of the solvent after cooling is 40-80°C; And / or, the pressure of the pressurized solvent is 0.6-5 MPa; And / or, the refining pressure is 1-2.5 MPa.

6. The method according to claim 1, wherein, The circulation ratios of the inner and outer circulations are each independently selected from 0 to 100. The dissolution is performed when the circulation ratio of the internal circulation and the external circulation is both 0; the internal circulation and the external circulation are performed when the circulation ratio of the internal circulation and the external circulation are both ≠ 0.

7. The method according to claim 1, wherein, The circulation ratios of the inner and outer circulations are each independently selected from 0 to 50.

8. The method according to claim 6, wherein, During a single activity recovery process, the number of cycles with a ratio of 0 is selected from 1 to 5. And / or, during a single activity recovery process, the single cycle time with a cycle ratio ≠ 0 is selected from 1 to 20 hours; And / or, in a single activity recovery process, the process with a cycle ratio of 0 is set in the initiation phase, intermediate phase, and termination phase; And / or, during a single activity recovery process, the total time of the internal and external circulation is 4-36 hours.

9. The method according to claim 8, wherein, During a single activity recovery process, the single cycle time with a cycle ratio ≠ 0 is selected from 4-15 hours; And / or, during a single activity recovery process, the total time of the internal and external circulation is 6-30 hours.

10. The method according to claim 1, wherein, The active metal in the active metal catalyst is selected from at least one metal element in the periodic table that has a stronger reducing power than hydrogen, and is selected from at least one metal element in Group IA, Group IIA, Group IIIA, Group IVA, Group IIB and Group VIII. And / or, the loading of the active metal in the active metal catalyst is 0.5-20 wt%; And / or, the support for the active metal catalyst is selected from at least one of basic metal salts, inorganic metal oxides, and molecular sieves; And / or, the active metal catalyst is selected from catalysts used in the preparation of 4-methyl-1-pentene by propylene dimerization.

11. The method according to claim 10, wherein, The active metal in the active metal catalyst is selected from at least one of Na, K, Li, Rb, Cs, Mg, Al, Zn, Fe, Sn, Pb, Ni and Pd; And / or, the loading of the active metal in the active metal catalyst is 3-10 wt%; And / or, the support for the active metal catalyst is selected from basic metal salts; And / or, the basic metal salt is selected from carbonates and / or acetates containing Na or K.

12. The method according to claim 11, wherein, The active metal in the active metal catalyst is selected from Na and / or K.

13. The method according to claim 1, wherein, The alkane solvent is selected from C3-C8 alkanes; And / or, the alkane solvent contains ≤10 ppmv of water and ≤10 ppmv of oxygen; And / or, the alkane solvent contains ≤5% olefins by volume.

14. The method according to claim 13, wherein, The alkane solvent is selected from C3-C5 alkanes; And / or, the alkane solvent contains ≤3 ppmv of water and ≤3 ppmv of oxygen; And / or, the alkane solvent contains ≤1 volume of olefins.

15. The method according to claim 14, wherein, The alkane solvent is selected from at least one of propane, n-butane, isobutane, n-pentane, and isopentane.

16. The method according to any one of claims 1-15, wherein, The method further includes: mixing the pressurized solvent and the fresh alkane solvent before performing the dissolution; The mass flow rate ratio of the pressurized solvent to the fresh alkane solvent is 1000:0-1. And / or, the method further includes: mixing the refined solvent and the fresh alkane solvent before performing the dissolution; The mass flow rate ratio of the refined solvent to the fresh alkane solvent is 1000:0-1; And / or, the method further includes heating the alkane solvent to 25-350°C prior to the dissolution.

17. The method according to claim 16, wherein, Prior to the dissolution, the alkane solvent is heated to 25-200°C.

18. A device for restoring the activity of an active metal catalyst, characterized in that, The apparatus includes: a reactor (1) with a catalyst bed, and an alkane solvent delivery pipeline (6), an internal circulation pipeline (8) and an external circulation pipeline (7) connected to the reactor (1). The active metal catalyst packed in the catalyst bed is dissolved with an alkane solvent (01) to obtain an active catalyst and a circulating solvent (02), and the circulating solvent is divided into two streams, which enter the inner circulation pipeline (8) and the outer circulation pipeline (7) respectively. According to the material flow direction, a cooler (2) and a pump (3) are sequentially installed on the internal circulation pipeline (8) to cool and pressurize the first stream of circulating solvent (02-i) to obtain pressurized solvent (03); a fractionation tower (5) is installed on the external circulation pipeline (7) to purify the second stream of circulating solvent (02-ii) to obtain purified solvent (04) and heavy stream (05); the pressurized solvent (03) and purified solvent (04) are independently recycled to the reactor (1); Wherein, the activity α of the catalyst whose activity has been restored satisfies Equation I: ， δ represents the activity of the active metal catalyst; i is selected as a positive number; φ i The flow rate of the heavy material stream is expressed in kg / h and t. i The time for activity recovery, in hours; ≥20%; In a single activity recovery process, the flow rate ratio of the first circulating solvent and the second circulating solvent satisfies Equation II: Where m and m' are the flow rates of the first and second circulating solvents, respectively, in kg / h; B is the circulation ratio of the internal circulation; N is the total number of times the circulation ratio is 0 in a single activity recovery process; n' is the n'th time of the circulation ratio is 0 in a single activity recovery process, and n' is selected from natural numbers from 1 to N; the circulation ratio refers to the volume ratio of the first and second circulating solvents to the active metal catalyst, respectively; the single activity recovery process refers to the activity recovery process in which the active metal catalyst is transformed into the activity recovery catalyst.

19. The apparatus according to claim 18, wherein, The reactor (1) is selected from fixed-bed reactors; And / or, the apparatus further includes: a heater (4) connecting the reactor (1) and the alkane solvent delivery line (6); And / or, the apparatus further includes: a first fresh solvent delivery line (9-i) connected to the internal circulation line (8) for returning the pressurized solvent (03) and fresh alkane solvent (06) to the reactor (1) after mixing. And / or, the apparatus further includes: a second fresh solvent delivery line (9-ii) connected to the external circulation line (7) for returning the refined solvent (04) and fresh alkane solvent (06) to the reactor (1) after mixing.

20. The apparatus according to claim 19, wherein, The heater (4) is also connected to the inner circulation line (8) and the outer circulation line (7). And / or, the device further includes: a temperature measuring point (T) connected to the top of the catalyst bed in the reactor (1).

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