Method and device for recovering activity of active metal catalyst

Abstract

The invention relates to the technical field of chemical production, in particular to a method and a device for recovering the activity of an active metal catalyst. The method comprises the following steps: dissolving an active metal catalyst by using an alkane solvent to obtain an activity-recovered catalyst and a circulating solvent; dividing the circulating solvent into two streams, and respectively carrying out internal circulation and external circulation; the internal circulation process comprises the following steps: cooling and pressurizing a first circulation solvent in sequence to obtain a pressurized solvent; the external circulation process comprises the following steps: refining the second circulation solvent to obtain a refined solvent and a heavy material flow; wherein the pressurized solvent and the refining solvent are respectively and independently returned and are dissolved; according to the method, the activity recovery of the active metal catalyst is improved, the operation period of the catalyst is prolonged, the technological process is simplified, and industrial production is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of chemical production, and in particular to a method for recovering the activity of an active metal catalyst and a device for recovering the activity of an active metal catalyst. Background Art

[0002] Active metal catalysts, such as alkali metal catalysts, have important industrial application value in the propylene dimerization reaction. The industrial production of 4-methyl-1-pentene has begun abroad since the 1960s, and the catalysts used in the production are single alkali metals or catalysts mixed with multiple alkali metals. Solid base catalysts mainly use alkali metals as active components and show ultra-high dimerization selectivity in the propylene dimerization reaction. At the same time, the selectivity of a single dimerization product can be improved by rationally designing the catalyst.

[0003] Since the solid base catalyst in the propylene dimerization reaction usually contains alkali metal elements, such as active metals such as Na and K, which are extremely sensitive to water and oxygen in the air, the loading and unloading of the catalyst is difficult and the safety risk is high. Therefore, the longest possible catalyst operation cycle or service life is an important factor for the industrial reliability and benefits of this technology.

[0004] It has been reported in the literature that when 4M1P is used as the target product of propylene dimerization, the optimal conditions determined by thermodynamics are temperature 127-177°C and pressure 10-15MPa. Due to the relatively harsh reaction conditions (high pressure), as the reaction proceeds, the catalyst, especially the supported metal catalyst, will be deactivated due to the growth of active metal grains or centers and the adsorption and coking of central colloids. In the actual propylene oligomerization process, in addition to the dimerization reaction, there will also be the generation of oligomerization byproducts such as propylene trimers and tetramers and high molecular weight polymer byproducts. These byproducts will occupy the active center of the catalyst, resulting in a decrease in the activity of the catalyst. For this reversible deactivation process, the performance of the catalyst can be restored by regeneration. At this time, if the catalyst is taken in situ activity recovery measures, the catalyst operation time and service life can be extended. Therefore, the in situ activity recovery of deactivated or partially deactivated active metal catalysts has practical significance for improving the efficiency of the device or the industrial reliability of this technology and reducing the consumption of active metals.

[0005] CN106179489A discloses a method for regenerating a deactivated catalyst, which comprises first treating the deactivated catalyst with an organic solvent, loading nickel on the treated catalyst, then charring the treated catalyst under the action of an oxygen-containing gas, and reducing the treated catalyst under a hydrogen atmosphere; then contacting the catalyst with an olefinic acid solution containing chitosan in a vacuum environment or an inert atmosphere, and finally drying and calcining the catalyst to obtain a catalyst with restored activity. The above-mentioned activity recovery method has to go through an oxidation or high-temperature charring step, which will destroy the catalyst structure, affect the relationship between the active metal and the carrier, and is complicated to operate, and the catalyst cannot be regenerated in situ, so it is not suitable for use in a fixed bed catalyst with an active metal as an active component.

[0006] Therefore, it is very necessary to develop a method for recovering the activity of active metal catalysts for processes using such catalysts, especially for industrial applications of propylene dimerization. Summary of the invention

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

[0008] The first aspect of the present invention provides a method for restoring the activity of an active metal catalyst, the method comprising: dissolving the active metal catalyst with an alkane solvent to obtain a catalyst with restored activity and a circulating solvent; dividing the circulating solvent into two streams, and performing internal circulation and external circulation respectively; the process of the internal circulation comprises: cooling and pressurizing the first circulating solvent in sequence to obtain a pressurized solvent; the process of the external circulation comprises: refining the second circulating solvent to obtain a refined solvent and a heavy stream; wherein the pressurized solvent and the refined solvent are independently returned and dissolved;

[0009] Wherein, the activity α of the catalyst with activity recovery satisfies Formula I: δ is the activity of the active metal catalyst; i is selected from a positive number; is the flow rate of the heavy material flow, kg / h; t i is the time for activity recovery, h;

[0010] In the present invention, unless otherwise specified, the activity recovery process of converting the active metal catalyst into the catalyst with restored activity is referred to as a single activity recovery process.

[0011] The inventors of the present invention have found that based on the deactivation mechanism of active metal catalysts, an alkane solvent is used to soak and dissolve the active metal catalyst with reduced activity, that is, based on the principle of like dissolves like, the different solubility of the alkane solvent in the catalyst with reduced activity is used for physical separation, and the macromolecular reaction byproducts on the catalyst are removed to expose the active center of the catalyst, thereby extending the operation cycle of the catalyst, reducing the number of catalyst loading and unloading times, and reducing the safety risk of catalyst loading and unloading. At the same time, the circulating solvent obtained by dissolution is divided into two streams for internal circulation and external circulation, and in particular, by regulating the circulation ratio of the internal circulation and the external circulation, the activity recovery and relative activity of the catalyst are more effectively improved.

[0012] The second aspect of the present invention provides a device for recovering the activity of an active metal catalyst, the device 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 loaded in the catalyst bed is dissolved with an alkane solvent to obtain an activity-restored catalyst and a circulating solvent, and the circulating solvent is divided into two streams, which enter the inner circulation pipeline and the outer circulation pipeline respectively;

[0014] According to the material flow direction, the inner circulation pipeline is provided with a cooler and a pump in sequence, which are used to cool and pressurize the first circulating solvent in sequence to obtain a pressurized solvent; the outer circulation pipeline is provided with a distillation tower, which is used to refine the second circulating solvent to obtain a refined solvent and a heavy material flow; the pressurized solvent and the refined solvent are independently reused in the reactor.

[0015] Through the above technical scheme, the present invention uses an alkane solvent to restore the activity of the active metal catalyst, and uses the principle of like dissolves like to remove the heavy substances in the active metal catalyst, thereby increasing the active center of the catalyst and improving the activity and relative activity of the catalyst; at the same time, combined with formula I, by regulating the flow rate of the heavy stream and the total time t of activity recovery, to achieve dynamic regulation of the activity α of the catalyst after activity recovery. In particular, in combination with Formula II, by regulating the flow ratio (i.e., m / m') of the first circulating solvent and the second circulating solvent, the flow rate of the heavy stream in Formula I is achieved. regulation, thereby shortening the total time for activity recovery.

[0016] At the same time, the method provided by the present invention realizes online activity recovery of active metal catalysts, prolongs the catalyst operation cycle, reduces the number of catalyst regeneration or unloading times, and improves the efficiency of the device; the method also simplifies the process flow and is convenient for industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1The present invention provides a schematic structural diagram of a device for recovering the activity of an active metal catalyst.

[0018] Description of Reference Numerals

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

[0020] 01. Alkane solvent; 02. Circulating solvent; 02-i. First circulating solvent; 02-ii. Second circulating solvent; 03. Pressurized solvent; 04. Refined solvent; 05. Heavy material flow; 06. Fresh alkane solvent; T. Temperature measurement point. DETAILED DESCRIPTION

[0021] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0022] In the present invention, unless otherwise specified, "first" and "second" do not indicate a sequence, nor do they limit the materials or steps. For example, "first" and "second" in "first circulating solvent" and "first circulating solvent" are only used to indicate that they are not the same circulating solvent.

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

[0024] The first aspect of the present invention provides a method for restoring the activity of an active metal catalyst, the method comprising: dissolving the active metal catalyst with an alkane solvent to obtain a catalyst with restored activity and a circulating solvent; dividing the circulating solvent into two streams, and performing internal circulation and external circulation respectively; the process of the internal circulation comprises: cooling and pressurizing the first circulating solvent in sequence to obtain a pressurized solvent; the process of the external circulation comprises: refining the second circulating solvent to obtain a refined solvent and a heavy stream; wherein the pressurized solvent and the refined solvent are independently returned and dissolved;

[0025] Wherein, the activity α of the catalyst with activity recovery satisfies Formula I: δ is the activity of the active metal catalyst; i is selected from a positive number; is the flow rate of the heavy material flow, kg / h; t i is the time for activity recovery, h;

[0026] In the present invention, unless otherwise specified, the activity of the catalyst after the activity recovery is determined based on the flow rate of the heavy stream. i Increase the flow rate of heavy material logistics Also gradually increases, and the activity α of the catalyst with activity recovery gradually recovers. Preferably, in Formula I, when the flow rate of the heavy stream is This indicates that the activity recovery of the active metal catalyst is complete.

[0027] In the present invention, unless otherwise specified, f is a function of the catalyst recovery after activity recovery associated with the total amount of the heavy material stream, obtained by correlating experimental data, Preferably,

[0028] In the present invention, unless otherwise specified, an active metal catalyst refers to a catalyst with decreased or deactivated activity relative to a fresh active metal catalyst with an activity of 100%, 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%, 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 the range consisting of any two numerical 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 the present invention, in Formula I, the total time for activity recovery includes not only the total time for dissolution, but also the total time for internal circulation / external circulation. Preferably, the total time for activity recovery is selected from 6-66h, preferably 10-54h.

[0031] In the present invention, the dissolution is to contact the alkane solvent and the active metal catalyst and soak and dissolve them to obtain a circulating solvent containing dissolved heavy substances and a catalyst with restored activity. In the present invention, the heavy substances of the active metal catalyst are selected from macromolecular reaction byproducts, for example, oligomerization byproducts such as propylene trimers and tetramers.

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

[0033] In some embodiments of the present invention, preferably, the circulation ratios of the inner circulation and the outer circulation are 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 the present invention, when the circulation ratio of the inner circulation and the outer circulation is 0 respectively, it means that no circulating solvent is generated, that is, the alkane solvent and the active metal catalyst are dissolved; when the circulation ratio of the inner circulation and the outer circulation are both ≠ 0, the circulating solvent is divided into a first circulating solvent and a second circulating solvent, and the inner circulation and the outer circulation are respectively carried out. That is to say, the dissolution and (the inner circulation and the outer circulation) belong to two different working states, respectively. When dissolving is carried out, the inner circulation and the outer circulation are closed, or, when the inner circulation and the outer circulation are carried out, the dissolution is closed; at the same time, the inner circulation and the outer circulation belong to a linkage operation, that is, the inner circulation and the outer circulation are carried out at the same time or are closed at the same time.

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

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

[0037] In some embodiments of the present invention, preferably, in a single activity recovery process, the single time when the circulation ratio is ≠0 is selected from 1-20 hours, preferably 4-15 hours. That is, when the circulation ratio of the inner cycle is ≠0 and the circulation ratio of the outer cycle is ≠0, the time of each cycle is selected from 1-20 hours, preferably 4-15 hours.

[0038] In the present invention, by regulating the number of times the circulation ratio is 0 and the total time when the circulation ratio is ≠0 (i.e., the total time when the circulation ratio is ≠0 = the single time when the circulation ratio is ≠0 × the number of times when the circulation ratio is ≠0), the activity recovery of the active metal catalyst can be effectively improved, thereby improving the relative activity of the catalyst.

[0039] In some embodiments of the present invention, preferably, in a single activity recovery process, a process with a circulation ratio of 0 is set in the initial stage, the middle stage, and the end stage.

[0040] In some embodiments of the present invention, preferably, in a single activity recovery process, the total time of the inner and outer cycles is 4-36 hours, preferably 6-30 hours. In the present invention, the total time of the inner and outer cycles includes: the total time when the cycle ratio is ≠0.

[0041] In some embodiments of the present invention, preferably, in a single activity recovery process, the flow ratio of the first circulating solvent to the second circulating solvent satisfies Formula II: Among them, m and m' are the flow rates of the first circulating solvent and the second circulating solvent respectively, kg / h; B is the circulation ratio of the internal circulation; N is the total number of operating conditions with a circulation ratio of 0 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 a natural number selected from 1-N.

[0042] In the present invention, as the activity recovery proceeds, the flow rate of the heavy logistics will tend to increase first and then decrease. If the internal and external circulation flow rate ratio is not adjusted, the time to separate the heavy logistics will increase, and the total time of activity recovery will also increase accordingly. Therefore, Formula II further defines the flow rate ratio of the first circulating solvent and the second circulating solvent in the operating condition where the n'th circulation ratio is 0. In this way, by adjusting the flow rate ratio of the first circulating solvent and the second circulating solvent in the circulating solvent, it is possible to achieve faster adjustment of the flow rate of the heavy logistics in Formula I. This in turn shortens the total time for activity recovery.

[0043] In the present invention, unless otherwise specified, Right now, In formula II, B is the circulation ratio of the internal cycle.

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

[0045] In the present invention, the external circulation is intended to purify the second circulating solvent to obtain a heavy stream and a refined solvent. Preferably, the refining conditions include: a pressure of 1-5 MPa, 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 whose reducing property is stronger than that of hydrogen, preferably selected from at least one of the metal elements in Group IA, Group IIA, Group IIIA, Group IVA, Group IIB and Group VIII, further preferably selected from at least one of Na, K, Li, Rb, Cs, Mg, Al, Zn, Fe, Sn, Pb, Ni and Pd, more preferably selected from Na and / or K.

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

[0048] In a 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 amount of Na and K meets the above limitation.

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

[0050] In the present invention, the type of the active metal catalyst has a wide selection range. Preferably, the active metal catalyst is selected from the catalyst for preparing 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; further 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 ≤10 ppmv, preferably ≤3 ppmv; the oxygen content is ≤10 ppmv, preferably ≤3 ppmv.

[0053] In some embodiments of the present invention, the presence of olefins in the alkane solvent will reduce the selectivity of the solvent, and its content should be reduced as much as possible. Preferably, the olefin content in the alkane solvent is ≤5% by volume, preferably ≤1% by volume.

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

[0055] In some embodiments of the present invention, preferably, the method further comprises: mixing the pressurized solvent and a fresh alkane solvent before performing the dissolving; further 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 comprises: mixing the refined solvent and a fresh alkane solvent before performing the dissolving; further preferably, the mass flow rate ratio of the refined solvent to the fresh alkane solvent is 1000:0-1.

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

[0058] The second aspect of the present invention provides a schematic diagram of a device for recovering the activity of an active metal catalyst. Figure 1 As shown by Figure 1 It can be seen that the device comprises: a reactor 1 provided 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 loaded in the catalyst bed is dissolved with the alkane solvent 01 to obtain the catalyst with restored activity and the circulating solvent 02, and the circulating solvent 02 is divided into two streams, which enter the inner circulation pipeline 8 and the outer circulation pipeline 7 respectively;

[0060] According to the material flow direction, the inner circulation pipeline 8 is provided with a cooler 2 and a pump 3 in sequence, which are used to cool and pressurize the first circulating solvent 02-i in sequence to obtain a pressurized solvent 03; the outer circulation pipeline 7 is provided with a distillation tower 5, which is used to refine the second circulating solvent 02-ii to obtain a refined solvent 04 and a heavy material flow 05; the pressurized solvent 03 and the refined solvent 04 are recycled to the reactor 1.

[0061] In the present invention, unless otherwise specified, the inlet of the inner circulation pipeline 8 (i.e., the outlet of the first circulating solvent) can be connected to the reactor outlet, or can be arranged in the reactor on the pipeline extending from the outlet, that is, the inlet of the inner circulation pipeline 8 is selected from 1-4 of the above-mentioned positions; the outlet of the inner circulation pipeline 8 (i.e., the inlet of the pressurized solvent) can be connected to the reactor inlet, or can be arranged in the reactor on the pipeline extending from the inlet, that is, the outlet of the inner circulation pipeline 8 is selected from 1-4 of the above-mentioned positions.

[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 set on the pipeline inside the reactor and extending to the outlet, that is, the inlet of the external circulation pipeline 7 is selected from 1-4 of the above-mentioned positions; the outlet of the external circulation pipeline 7 (i.e., the inlet of the refined solvent) can be connected to the reactor inlet, or it can be set on the pipeline inside the reactor and extending to the inlet, that is, the outlet of the external circulation pipeline 7 is selected from 1-4 of the above-mentioned positions.

[0063] In the present invention, preferably, Figure 1 As shown, the reactor 1 is selected from a fixed bed reactor.

[0064] In the present invention, preferably, Figure 1 As shown, the device further comprises: a heater 4 connected to the reactor 1 and the alkane solvent delivery pipeline 6, for heating the alkane solvent 01 and then dissolving it.

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

[0066] In the present invention, preferably, Figure 1 As shown, the device further comprises: a second fresh solvent delivery pipeline 9 - ii connected to the external circulation pipeline 7 , for mixing the refined solvent 04 and the fresh alkane solvent 06 and returning them to the reactor 1 .

[0067] In the present invention, preferably, Figure 1 As shown, the heater 4 is also connected to an inner circulation pipeline 8 and an outer circulation pipeline 7, which are used to respectively heat the pressurized solvent 03 and the refined solvent 04 and then enter the reactor 1.

[0068] In the present invention, preferably, Figure 1 As shown, the device also includes: a top temperature measuring point T connected to the catalyst bed in the reactor 1 for detecting the temperature of the catalyst bed.

[0069] According to a particularly preferred embodiment of the present invention, a method for recovering the activity of an active metal catalyst comprises: dissolving the active metal catalyst with an alkane solvent to obtain a catalyst with restored activity and a circulating solvent; dividing the circulating solvent into two streams, and performing internal circulation and external circulation respectively; the process of the internal circulation comprises: cooling and pressurizing the first circulating solvent in sequence to obtain a pressurized solvent; the process of the external circulation comprises: refining the second circulating solvent to obtain a refined solvent and a heavy stream; wherein the pressurized solvent and the refined solvent are returned independently and the dissolution is performed;

[0070] Wherein, the activity α of the catalyst with activity recovery satisfies Formula I: δ is the activity of the active metal catalyst; i is selected from a positive number; is the flow rate of the heavy material flow, kg / h; t i is the time for activity recovery, h;

[0071] Wherein, the circulation ratio of the inner circulation and the outer circulation is independently selected from 0-50, and the circulation ratio refers to the volume ratio of the first circulating solvent and the second circulating solvent to the active metal catalyst respectively; in a single activity recovery process, the number of times the circulation ratio is 0 is selected from 1-5 times, and the single activity recovery process refers to the activity recovery process of converting the active metal catalyst into the activity-recovered catalyst;

[0072] Wherein, in a single activity recovery process, the flow ratio of the first circulating solvent and the second circulating solvent satisfies Formula II: Among them, m and m' are the flow rates of the first circulating solvent and the second circulating solvent respectively, kg / h; B is the circulation ratio of the internal circulation; N is the total number of operating conditions with a circulation ratio of 0 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 a natural number selected from 1-N.

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

[0074] Example 1

[0075] Devices such as Figure 1 As shown, the device comprises: a reactor 1 provided with a catalyst bed, an alkane solvent delivery pipeline 6, an internal circulation pipeline 8 and an external circulation pipeline 7 connected to 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 inner circulation pipeline 8 is provided with a cooler 2, a pump 3 and a first fresh solvent delivery pipeline 9-i in sequence, and the outer circulation pipeline 7 is provided with a fractionation tower 5 and a second fresh solvent delivery pipeline 9-ii in sequence; the upper part of the catalyst bed is connected to the temperature measuring point T;

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

[0078] The method is carried out in the above-mentioned device, and the method comprises:

[0079] (1) heating an alkane solvent (propane, olefin content ≤1 volume %, water content ≤3 ppmv, oxygen content ≤3 ppmv) to 50° C., and dissolving 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 amount is 5 wt %, and the carrier is selected from potassium carbonate) first (temperature is 80° C., pressure is 4 MPa, single time is 4 h), and then performing internal circulation and external circulation, and dividing the circulating solvent into a first circulating solvent and a second circulating solvent with a mass ratio of 16:1;

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

[0081] When the above-mentioned internal circulation and external circulation time is 6 hours, adjust the circulation ratio to 0, close the internal circulation pipeline and the external circulation pipeline, allow the propane to dissolve in the catalyst bed for 4 hours, then open the internal circulation pipeline and the external circulation pipeline, and then circulate the internal and external circulation for 6 hours, then close the internal circulation pipeline and the external circulation pipeline, and so on, so that the operating condition with a circulation ratio of 0 is operated 4 times in a single activity recovery process.

[0082] After the first operation condition with a circulation ratio of 0 is completed, the inner circulation pipeline and the outer circulation pipeline are opened, according to Formula II: Adjust the flow ratio of the first circulating solvent to the second circulating solvent to 16:1 After the second operation condition with a circulation ratio of 0 is completed, open the inner circulation pipeline and the outer circulation pipeline, and adjust the flow ratio of the first circulation solvent and the second circulation solvent to 8:1. After the third operation condition with a circulation ratio of 0 is completed, the inner circulation pipeline and the outer circulation pipeline are opened, and the mass ratio of the first circulation solvent to the second circulation solvent is adjusted to 16:3. After the fourth operation condition with a circulation ratio of 0 is completed, the inner circulation pipeline and the outer circulation pipeline are opened, and the mass ratio of the first circulation solvent to the second circulation solvent is adjusted to 4:1. The catalyst S1 with restored activity was obtained.

[0083] Example 2

[0084] According to the device of Example 1,

[0085] The method of Example 1 is followed, except that the single dissolution time is adjusted to 12 hours, and the single time of the inner circulation and the outer circulation is adjusted to 8 hours; that is,

[0086] When the time of the above-mentioned internal circulation and external circulation is 8 hours, the circulation ratio is adjusted to 0, the internal circulation pipeline and the external circulation pipeline are closed, and propane is dissolved in the catalyst bed for 12 hours, and then the internal circulation pipeline and the external circulation pipeline are opened, and the circulation is repeated for 8 hours, and then the internal circulation pipeline and the external circulation pipeline are closed. The operation condition of the circulation ratio of 0 is completed twice in one activity recovery process;

[0087] After the first operation condition with a circulation ratio of 0 is completed, the inner circulation pipeline and the outer circulation pipeline are opened, and the mass ratio of the first circulation solvent to the second circulation solvent is adjusted to 8:1; after the second operation condition with a circulation ratio of 0 is completed, the inner circulation pipeline and the outer circulation pipeline are opened, and the mass ratio of the first circulation solvent to the second circulation solvent is adjusted to 4:1;

[0088] The remaining conditions were the same, and the catalyst S2 with restored activity was obtained.

[0089] Example 3

[0090] According to the device of Example 1,

[0091] The method of Example 1 is followed, except that the alkane solvent is replaced with n-pentane (olefin content ≤ 1 volume %, water content ≤ 3 ppmv, oxygen content ≤ 3 ppmv),

[0092] The remaining conditions were the same, and the catalyst S3 with restored activity was obtained.

[0093] Example 4

[0094] According to the device of Example 1,

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

[0096] The remaining conditions were the same, and the catalyst S4 with restored activity was obtained.

[0097] Example 5

[0098] According to the device of Example 1,

[0099] According to the method of Example 1, the difference is that

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

[0101] The remaining conditions were the same, and the catalyst S5 with restored activity was obtained.

[0102] Comparative Example 1

[0103] The device according to Example 1 is different in that the device does not contain the external circulation pipe 7, the fractionation tower 5 and the second fresh solvent delivery pipeline 9-ii;

[0104] According to the method of Example 1, the method is carried out in the above-mentioned device, that is,

[0105] In step (2), the circulating solvent is internally circulated, cooled to 50° C. and pressurized to 4 MPa in sequence, and the pressurized solvent obtained is mixed with fresh propane and heated to perform the above dissolution to obtain the catalyst DS1 with restored activity.

[0106] Comparative Example 2

[0107] The device according to Example 1 is different in that the device does not contain the internal circulation pipeline 8, the cooler 2, the pump 3 and the first fresh solvent delivery pipeline 9-i;

[0108] According to the method of Example 1, the method is carried out in the above-mentioned device, that is,

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

[0110] Table 1

[0111]

[0112] Note: In the present invention, Right now,

[0113] Table 1

[0114]

[0115]

[0116] It can be seen from the results in Table 1 that, compared with Comparative Examples 1-2, the method provided by the present invention can effectively improve the activity of the active metal catalyst, and further effectively improve the degree of activity recovery of the active metal catalyst.

[0117] At the same time, compared with Example 4, Example 1 more effectively improves the degree of catalyst activity recovery by regulating the internal and external circulation ratio of the alkane solvent after each dissolution.

[0118] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to 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 comprises: dissolving an active metal catalyst with an alkane solvent to obtain an activity-restored catalyst and a circulating solvent; dividing the circulating solvent into two streams, and performing internal circulation and external circulation respectively, wherein the process of the internal circulation comprises: sequentially cooling and pressurizing the first circulating solvent to obtain a pressurized solvent, and the process of the external circulation comprises: refining the second circulating solvent to obtain a refined solvent and a heavy material stream; wherein the pressurized solvent and the refined solvent are independently returned and the dissolution is performed; Wherein, the activity α of the catalyst with activity recovery satisfies Formula I: δ is the activity of the active metal catalyst; i is selected from a positive number; is the flow rate of the heavy material flow, kg / h; t i is the time for activity recovery, h; 2. The method according to claim 1, wherein: In Formula I, when It 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%, preferably 20-80%; the total time for activity recovery is selected from 6-66h, preferably 10-54h; And / or, the relative activity β of the catalyst with restored activity is ≥ 0.7, preferably 0.7-2.5, and the relative activity β = (activity α of the catalyst with restored activity / activity δ of the active metal catalyst) -1.

3. The method according to claim 1 or 2, wherein: The dissolution conditions include: temperature of 25-350°C; pressure of 0.5-11 MPa; single time of 1-20 hours; Preferably, the dissolution conditions include: temperature of 25-200°C; pressure of 0.5-5MPa; single time of 4-15h; and / or, the temperature of the solvent after cooling is 40-90° C., preferably 40-80° C.; and / or, the pressure of the pressurized solvent is 0.6-11 MPa, preferably 0.6-5 MPa; And / or, the refining conditions include: pressure of 1-5 MPa, preferably 1-2.5 MPa, reflux ratio of 1-3, and number of theoretical plates of 15-30.

4. The method according to any one of claims 1 to 3, wherein: The circulation ratio of the inner circulation and the outer circulation is independently selected from 0-100, preferably 0-50, and the circulation ratio refers to the volume ratio of the first circulating solvent and the second circulating solvent to the active metal catalyst respectively; And / or, when the circulation ratios of the internal circulation and the external circulation are both 0, the dissolution is carried out; when the circulation ratios of the internal circulation and the external circulation are both ≠ 0, the internal circulation and the external circulation are carried out.

5. The method according to claim 4, wherein: In a single activity recovery process, the number of times the circulation ratio is 0 is selected from 1 to 5 times, and the single activity recovery process refers to an activity recovery process in which the active metal catalyst is converted into the activity-recovered catalyst; And / or, in a single activity recovery process, the single time of the circulation ratio ≠ 0 is selected from 1-20h, preferably 4-15h; and / or, in a single activity recovery process, a process with a circulation ratio of 0 is set at an initial stage, an intermediate stage, and an end stage; And / or, in a single activity recovery process, the total time of the internal circulation and the external circulation is 4-36 hours, preferably 6-30 hours.

6. The method according to claim 4 or 5, wherein: In a single activity recovery process, the flow ratio of the first circulating solvent and the second circulating solvent satisfies Formula II: Among them, m and m' are the flow rates of the first circulating solvent and the second circulating solvent respectively, kg / h; B is the circulation ratio of the internal circulation; N is the total number of operating conditions with a circulation ratio of 0 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 a natural number selected from 1-N.

7. The method according to any one of claims 1 to 6, wherein: The active metal in the active metal catalyst is selected from at least one metal element in the periodic table whose reducing property is stronger than that of hydrogen, preferably selected from at least one of the metal elements in Group IA, Group IIA, Group IIIA, Group IVA, Group IIB and Group VIII, further preferably selected from at least one of Na, K, Li, Rb, Cs, Mg, Al, Zn, Fe, Sn, Pb, Ni and Pd, more preferably selected from Na and / or K; and / or, the active metal loading in the active metal catalyst is 0.5-20wt%, preferably 3-10wt%; And / or, the carrier of the active metal catalyst is selected from at least one of a metal alkaline salt, an inorganic metal oxide and a molecular sieve, preferably a metal alkaline salt; further preferably, the metal alkaline salt is selected from carbonates and / or acetates containing Na or K; And / or, the active metal catalyst is selected from the catalyst for preparing 4-methyl-1-pentene by propylene dimerization.

8. The method according to any one of claims 1 to 7, wherein: The alkane solvent is selected from C3-C8 alkanes, preferably selected from C3-C5 alkanes, and more preferably selected from at least one of propane, n-butane, isobutane, n-pentane and isopentane; and / or, the water content in the alkane solvent is ≤10 ppmv, preferably ≤3 ppmv; the oxygen content is ≤10 ppmv, preferably ≤3 ppmv; And / or, the olefin content in the alkane solvent is ≤5 volume %, preferably ≤1 volume %.

9. The method according to any one of claims 1 to 8, wherein: The method further comprises: mixing the pressurized solvent and a fresh alkane solvent and then performing the dissolving; and / or, the mass flow rate ratio of the pressurized solvent to the fresh alkane solvent is 1000:0-1; And / or, the method further comprises: mixing the refined solvent and a fresh alkane solvent before performing the dissolving; and / or, the mass flow rate ratio of the refined solvent to the fresh alkane solvent is 1000:0-1; And / or, the method further comprises: before the dissolving, heating the alkane solvent to 25-350°C, preferably 25-200°C.

10. A device for recovering the activity of an active metal catalyst, characterized in that: The device comprises: a reactor (1) provided 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 loaded in the catalyst bed is dissolved with an alkane solvent (01) to obtain a catalyst with restored activity and a circulating solvent (02), and the circulating solvent is divided into two streams, which respectively enter the inner circulation pipeline (8) and the outer circulation pipeline (7); According to the material flow direction, the inner circulation pipeline (8) is provided with a cooler (2) and a pump (3) in sequence for cooling and pressurizing the first circulating solvent (02-i) in sequence to obtain a pressurized solvent (03); the outer circulation pipeline (7) is provided with a distillation tower (5) for refining the second circulating solvent (02-ii) to obtain a refined solvent (04) and a heavy material flow (05); the pressurized solvent (03) and the refined solvent (04) are independently recycled to the reactor (1).

11. The device according to claim 10, wherein: The reactor (1) is selected from a fixed bed reactor; And / or, the device further comprises: a heater (4) connecting the reactor (1) and the alkane solvent delivery pipeline (6); And / or, the device further comprises: a first fresh solvent delivery pipeline (9-i) connected to the internal circulation pipeline (8), for mixing the pressurized solvent (03) and the fresh alkane solvent (06) and returning the mixture to the reactor (1); And / or, the device further comprises: a second fresh solvent delivery pipeline (9-ii) connected to the external circulation pipeline (7), for mixing the refined solvent (04) and the fresh alkane solvent (06) and returning the mixture to the reactor (1).

12. The device according to claim 11, wherein: The heater (4) is also connected to an inner circulation pipeline (8) and an outer circulation pipeline (7); And / or, the device further comprises: a temperature measuring point (T) connected to the top of the catalyst bed in the reactor (1).

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