Method and device for prolonging service life of active metal catalyst on line

Abstract

The invention relates to the technical field of chemical production, in particular to a method and device for prolonging the service life of an active metal catalyst on line, and the method comprises the following steps: respectively carrying out activity recovery on the active metal catalyst by using an alkane solvent and a mixed gas containing H2, an ammonia-containing compound and an inert gas; the activity recovery comprises solvent circulation desolvation and hydrogen circulation cracking, and the solvent circulation desolvation comprises dissolution, internal circulation and / or external circulation; when gamma is more than gamma hydrogen and less than gamma solution, carrying out solvent circulation desolvation; when gamma is smaller than or equal to gamma hydrogen, hydrogen cycle cracking is carried out; when gamma is greater than or equal to gamma solution, reacting; gamma is the activity% of the catalyst at any stage; gamma hydrogen is a critical value for hydrogen cycle cracking, and gamma hydrogen is less than or equal to 60%; the gamma solution is a critical value of the solvent circulation desolvation, and the gamma solution is more than 60% and less than or equal to 80%. The method adopts a mode of combining solvent circulation desolvation and hydrogen circulation cracking, so that the activity of the catalyst is effectively improved, the service life is prolonged, and the number of times of unloading the catalyst is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of chemical production, and in particular to a method for online prolonging the service life of an active metal catalyst and a device for online prolonging the service life 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] 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 center agglomeration and central colloid adsorption and coking. 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. At this time, if measures are taken to restore the activity of the catalyst, the operating time and service life of the catalyst can be extended. Therefore, the in-situ activity recovery of deactivated or partially deactivated active metal catalysts is of practical significance for improving the efficiency of the device or the industrial reliability of this technology and reducing the consumption of active metals.

[0004] CN106179489A discloses a method for regenerating a deactivated catalyst, which includes first treating the deactivated catalyst with an organic solvent, loading nickel on the treated catalyst, then charring the catalyst under the action of an oxygen-containing gas, reducing the treated catalyst under a hydrogen atmosphere, then soaking the catalyst in 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 is not suitable for fixed-bed catalysts with active metals as active components because it has to go through oxidation or high-temperature charring steps.

[0005] CN112512997A discloses a catalyst and method for propylene dimerization. Prior to the dimerization reaction, the alkali metal catalyst may be exposed to hydrogen to ensure that the catalytic metal is in a metallic state when some oxidation occurs during calcination. However, when the alkali metal catalyst is activated by a large amount of hydrogen, it is easy to cause the catalyst grains to aggregate and grow, thereby affecting the catalyst active center and reducing the activity of the catalyst.

[0006] The activity and operation cycle of active metal catalysts, especially alkali metal catalysts, have a great influence on the technical level of propylene dimerization to prepare 4-methyl-1-pentene, among which the service life of the catalyst is the core and key of the technology. The decrease in the activity of active metal catalysts will affect the number of loading and unloading and the service life of the catalyst. The difficulty of loading and unloading active metal catalysts is relatively large, which further reduces the operating safety factor of the device. From the perspective of the entire life cycle of the catalyst, there is currently no relevant literature reporting on the use of appropriate activity recovery methods according to the different stages of deactivation of the active metal catalyst. Therefore, the development of an advanced method for online extension of the service life of active metal catalysts is very necessary for processes using such catalysts, especially for industrial applications of propylene dimerization reactions. Summary of the invention

[0007] The purpose of the present invention is to overcome the problems of the existing methods for recovering the activity of active metal catalysts, such as low activity recovery degree resulting in short service life, frequent unloading times, low safety, and complex process flow, and to provide a method for online extending the service life of active metal catalysts and a device for online extending the service life of active metal catalysts. The method adopts a combination of solvent circulation dissolution and hydrogen circulation cracking to effectively improve the activity of the catalyst, extend the service life, and reduce the number of unloading times.

[0008] In order to achieve the above-mentioned object, the first aspect of the present invention provides a method for extending the service life of an active metal catalyst online, the method comprising: using an alkane solvent and a mixed gas containing H2, an ammonia compound and an inert gas to respectively restore the activity of the active metal catalyst; wherein the activity recovery comprises: solvent circulation dissolution and hydrogen circulation cracking, and the solvent circulation dissolution comprises dissolution, internal circulation and / or external circulation;

[0009] Among them, when γ 氢 <γ<γ 溶 , the solvent is circulated and stripped; when γ≤γ 氢 , the hydrogen cycle cracking is carried out; when γ ≥ γ 溶 , to react; γ is the activity of the catalyst at any stage, %; γ 氢 is the critical value for the hydrogen cycle cracking, γ 氢 ≤60%;γ 溶 The critical value for the solvent circulation stripping is 60% < γ 溶 ≤80%.

[0010] In the present invention, the activity γ of the catalyst at any stage is equivalent to the conversion rate of the reaction product at any stage, and the conversion rate of the reaction product at any stage is calculated based on the quantitative analysis of the reaction product at any stage.

[0011] In the present invention, unless otherwise specified, the solvent circulation stripping, hydrogen circulation cracking and reaction each have a working state and a closed state independently, and these three working conditions are performed in a single manner. That is, when the activity of the catalyst at any stage satisfies: γ 氢 <γ<γ 溶 , the hydrogen cycle cracking and reaction are both in a closed state, and the solvent cycle stripping is in a working state; when the activity of the catalyst at any stage satisfies: γ≤γ 氢 , the solvent circulation stripping and reaction are both in a closed state, and the hydrogen circulation cracking is in a working state; when the activity of the catalyst at any stage satisfies: γ ≥ γ 溶 , the solvent circulation dissolution and hydrogen circulation cracking are both in a closed state, and the reaction is in a working state.

[0012] In the present invention, unless otherwise specified, the catalyst at any stage includes but is not limited to the active metal catalyst, the catalyst after solvent circulation dissolution, the catalyst after reaction, the catalyst after hydrogen circulation cracking, etc.

[0013] Preferably, the method comprises the following steps:

[0014] (1) contacting the alkane solvent with the active metal catalyst and performing the solvent circulation stripping, wherein the obtained catalyst after solvent circulation stripping satisfies: γ≥γ 溶 ;

[0015] (2) circulating the solvent to dissolve the catalyst and perform the reaction until the catalyst satisfies the following conditions: 氢 <γ<γ 溶 , repeat the above step (1);

[0016] (3) When the catalyst satisfies the following conditions after the reaction: γ≤γ 氢 , the hydrogen cycle cracking is carried out, and the catalyst obtained after hydrogen cycle cracking satisfies: γ≥γ 溶 ;

[0017] (4) The hydrogen is circulated and cracked to the catalyst for the reaction until the catalyst after the reaction satisfies: γ < γ 溶 , to remove the agent.

[0018] The second aspect of the present invention provides an online device for extending the service life of an active metal catalyst, wherein the method provided in the first aspect is carried out in the device, and the device comprises: a reactor provided with a catalyst bed, an internal circulation pipeline, an external circulation pipeline, a hydrogen circulation cracking pipeline, an alkane solvent delivery pipeline, a reaction raw material delivery pipeline and a reaction product delivery pipeline connected to the reactor, and a hydrogen delivery pipeline, an inert gas delivery pipeline and an ammonia-containing compound delivery pipeline connected to the hydrogen circulation cracking pipeline;

[0019] Wherein, according to the material flow direction, the inner circulation pipeline is provided with a cooler and a pump in sequence, the outer circulation pipeline is provided with a fractionation tower, and the hydrogen circulation cracking pipeline is provided with a condenser, a liquid separation tank and a compressor in sequence;

[0020] Among them, the inner circulation pipeline, the outer circulation pipeline and the hydrogen circulation cracking pipeline each independently have a working state and a closed state, so that the alkane solvent or the mixed gas is respectively in contact with the active metal catalyst loaded in the catalyst bed and performs solvent circulation dissolution and hydrogen circulation cracking, and the mixed gas contains H2, ammonia-containing compounds and inert gases.

[0021] Through the above technical scheme, the method provided by the present invention adopts a combination of solvent circulation dissolution and hydrogen circulation cracking, fully utilizes the principles of similar compatibility and hydrogen circulation cracking, effectively removes heavy substances from active metal catalysts, and recovers and fixes the active components of the catalyst in situ, and based on the activity γ of the catalyst at any stage, the activity recovery of the catalyst and the alternation of the reaction are realized online, thereby extending the service life of the catalyst and correspondingly reducing the number of unloading times; in particular, by regulating the components of the mixed gas during the hydrogen circulation cracking cycle, the dispersion recovery rate of the catalyst is more effectively improved.

[0022] At the same time, the method provided by the present invention realizes online activity recovery of active metal catalysts, prolongs the service life and operation cycle of the catalyst, 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

[0023] Figure 1 The present invention is a schematic diagram of the structure of a device for online prolonging the service life of an active metal catalyst.

[0024] Description of Reference Numerals

[0025] 1. Reactor; 2. Cooler; 3. Pump; 4. Heater; 5. Fractionator; 6. Condenser; 7. Separator; 8. Compressor; 01. Internal circulation pipeline; 02. External circulation pipeline; 03. Hydrogen circulation cracking pipeline; 04. Alkane solvent delivery pipeline; 05. Hydrogen delivery pipeline; 06. Inert gas delivery pipeline; 07. Ammonia-containing compound delivery pipeline; 08-i. First fresh solvent delivery pipeline; 08-ii. Second fresh solvent delivery pipeline; 09. Reaction raw material delivery pipeline; 010. Reaction product delivery pipeline;

[0026] T1, first temperature measuring point; T2, second temperature measuring point; A1, first gas detection point; A2, second gas detection point; PC, pressure control instrument; FC, relaxation gas flow control instrument; M, compressor motor; 11, alkane solvent; 12, alkane-rich logistics; 13, pressurized solvent; 14, refined solvent; 15, heavy logistics; 16, mixed gas; 17, hydrogen; 18, inert gas; 19, ammonia-containing compounds; 20, gas-liquid mixture; 21, gas; 22, circulating gas; 23, fresh alkane solvent; 24, reaction raw materials; 25, reaction products. DETAILED DESCRIPTION

[0027] 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.

[0028] In the present invention, unless otherwise specified, "first" and "second" do not indicate a sequence or limit to each material or step, but are only used to distinguish or indicate that they are not the same material or step. For example, "first" and "second" in "first temperature measuring point" and "second temperature measuring point" are only used to distinguish or indicate that they are not the same temperature measuring point.

[0029] 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.

[0030] The first aspect of the present invention provides a method for extending the service life of an active metal catalyst online, the method comprising: using an alkane solvent and a mixed gas containing H2, an ammonia compound and an inert gas to respectively restore the activity of the active metal catalyst; wherein the activity recovery comprises: solvent circulation dissolution and hydrogen circulation cracking, and the solvent circulation dissolution comprises dissolution, internal circulation and / or external circulation;

[0031] Among them, when γ 氢 <γ<γ 溶 , the solvent is circulated and stripped; when γ≤γ 氢 , the hydrogen cycle cracking is carried out; when γ ≥ γ 溶 , to react; γ is the activity of the catalyst at any stage, %; γ 氢is the critical value for the hydrogen cycle cracking, γ 氢 ≤60%;γ 溶 The critical value for the solvent circulation stripping is 60% < γ 溶 ≤80%.

[0032] The inventors of the present invention have found that based on the deactivation mechanism of the propylene dimerization catalyst, the deactivated or partially deactivated catalyst is treated with an alkane solvent. The essence of this method is to physically separate and detach and restore the active center of the catalyst based on the principle that the alkane solvent has a strong solubility for the macromolecular reaction byproducts adsorbed on the active center of the catalyst under certain conditions. Since the alkane solvent can only remove the oily and macromolecular byproducts on the catalyst, it is impossible to completely dissolve the colloid part. At the same time, the deactivated or partially deactivated catalyst is cracked by hydrogen circulation, so that the macromolecular byproduct colloid can react with hydrogen and desorb the active center of the catalyst at a certain gas velocity. Therefore, the combination of these two methods can further improve the activity recovery of the catalyst, thereby extending the operating cycle of the catalyst online.

[0033] The inventors of the present invention have also discovered that during the hydrogen cycle cracking process, by adding ammonia-containing compounds as stabilizers to the mixed gas, and in particular by further regulating the volume concentration of the ammonia-containing compounds, the active center positions of the catalyst can be fixed during the hydrogen activation process, thereby avoiding the aggregation of active centers and improving the dispersion of the catalyst.

[0034] 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 of the active metal catalyst is less than 100%.

[0035] In the present invention, unless otherwise specified, the activity recovery is selected from the following: firstly solvent circulation dissolution and then hydrogen circulation cracking, or firstly hydrogen circulation cracking and then solvent circulation dissolution, depending on the activity of the active metal catalyst. Preferably, the activity recovery is selected from the following: first solvent circulation dissolution and then hydrogen circulation cracking, which is more conducive to improving the service life of the active metal catalyst.

[0036] In some embodiments of the invention, 氢 <γ 溶 Under the premise that 60% < γ 溶 ≤80%, for example, 60.1%, 65%, 70%, 75%, 80%, and any value in a range consisting of any two values.

[0037] In some embodiments of the present invention, further preferably, 20%≤γ 氢≤60%, for example, 20%, 30%, 40%, 50%, 60%, and any value in a range consisting of any two values.

[0038] In some embodiments of the present invention, preferably, the method comprises the following steps:

[0039] (1) contacting the alkane solvent with the active metal catalyst and performing the solvent circulation stripping, wherein the obtained catalyst after solvent circulation stripping satisfies: γ≥γ 溶 ;

[0040] (2) circulating the solvent to dissolve the catalyst and carry out the reaction until the catalyst satisfies the following conditions: 氢 <γ<γ 溶 , repeat the above step (1);

[0041] (3) When the catalyst satisfies the following conditions after the reaction: γ≤γ 氢 , the hydrogen cycle cracking is carried out, and the catalyst obtained after hydrogen cycle cracking satisfies: γ≥γ 溶 ;

[0042] (4) The hydrogen is circulated and cracked to the catalyst for the reaction until the catalyst satisfies: γ<γ 溶 , to remove the agent.

[0043] In some embodiments of the present invention, preferably, the number of operations of the solvent circulation dissolution n≥1 times, and n is preferably selected from 1-5 times; the number of operations of the hydrogen circulation cracking m is selected from 1 time.

[0044] In some specific embodiments of the present invention, preferably, after the (n-1)th (1≤n≤5) solvent circulation dissolution, the time for the catalyst to carry out the reaction after the solvent circulation dissolution is greater than 15 days; after the nth (1≤n≤5) solvent circulation dissolution, the time for the catalyst to carry out the reaction after the solvent circulation dissolution is ≤15 days.

[0045] In some embodiments of the present invention, preferably, the dispersion recovery rate of the active metal in the catalyst after hydrogen circulation cracking is ≥75%, for example, 75%, 80%, 82%, 85%, 88%, 90%, 95%, 99%, and any value in the range composed of any two numerical values, preferably 80-99%, wherein the dispersion recovery rate = the dispersion of the active metal in the catalyst after hydrogen circulation cracking / the dispersion of the active metal in the fresh active metal catalyst.

[0046] In some embodiments of the present invention, preferably, the activity of the active metal catalyst is ≤80%, for example, 60%, 65%, 70%, 75%, 80%, and any value in the range of any two values, preferably 60-80%.

[0047] 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; further preferably, the active metal in the active metal catalyst is selected from at least one of the metal elements in Group IA, Group IIA, Group IIIA, Group IVA, Group IIB and Group VIII; more preferably, 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; most preferably, the active metal in the active metal catalyst is selected from Na and / or K.

[0048] 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 %.

[0049] 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.

[0050] In some embodiments of the present invention, preferably, 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. In the present invention, the use of a preferred carrier is more conducive to the hydrocracking of by-products.

[0051] 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.

[0052] In some embodiments of the present invention, preferably, the solvent circulation dissolution process includes: contacting the alkane alkyl group with an active metal catalyst and dissolving it, and the obtained alkane-rich logistics is subjected to the internal circulation and / or external circulation; wherein, the internal circulation process includes: successively cooling and pressurizing the alkane-rich logistics, and returning the pressurized solvent obtained and mixing it into the alkane solvent; the external circulation process includes: refining the alkane-rich logistics, and returning the refined solvent obtained and mixing it into the alkane solvent.

[0053] In the present invention, in the process of solvent circulation dissolution, the three working conditions of dissolution, internal circulation and external circulation can be arbitrarily combined, and can have working state and closed state respectively, wherein the dissolution working condition is performed alone; the internal circulation working condition and the external circulation working condition can be performed alone or simultaneously. That is, when the dissolution is in the working state, the internal circulation and / or the external circulation are both in the closed state; when the internal circulation is in the working state, the dissolution is in the closed state, and the external circulation can be in the closed state or in the working state; when the external circulation is in the working state, the dissolution is in the closed state, and the internal circulation can be in the closed state or in the working state.

[0054] In the present invention, subjecting the alkane-rich stream to the internal circulation and / or external circulation means that the alkane-rich stream can be subjected to the internal circulation, can be subjected to the external circulation, or the alkane-rich stream can be divided into two streams and subjected to the internal circulation and the external circulation respectively at the same time.

[0055] In a first specific embodiment of the present invention, the alkane-rich logistics is first subjected to the internal circulation, the obtained pressurized solvent is returned and mixed with the alkane solvent for the dissolution, the obtained alkane-rich logistics is then subjected to the external circulation, the obtained refined solvent is returned and mixed with the alkane solvent for the dissolution, and the obtained alkane-rich logistics repeats the above operation, that is, dissolution-internal circulation-dissolution-external circulation-dissolution...; or, the alkane-rich logistics is first subjected to the internal circulation, the obtained pressurized solvent is returned and mixed with the alkane solvent, and then subjected to the external circulation, the obtained refined solvent is returned and mixed with the alkane solvent for the dissolution, and the obtained alkane-rich logistics repeats the above operation, that is, dissolution-internal circulation-external circulation-dissolution...

[0056] In a second specific embodiment of the present invention, the alkane-rich logistics is first subjected to the external circulation, the obtained refined solvent is returned and mixed with the alkane solvent for the dissolution, the obtained alkane-rich logistics is then subjected to the internal circulation, the obtained pressurized solvent is returned and mixed with the alkane solvent for the dissolution, and the obtained alkane-rich logistics repeats the above operation, that is, dissolution-external circulation-dissolution-internal circulation-dissolution...; or, the alkane-rich logistics is first subjected to the external circulation, the obtained refined solvent is returned and mixed with the alkane solvent, and then subjected to the internal circulation, the obtained pressurized solvent is returned and mixed with the alkane solvent for the dissolution, and the obtained alkane-rich logistics repeats the above operation, that is, dissolution-external circulation-internal circulation-dissolution...

[0057] In a third specific embodiment of the present invention, the alkane-rich stream is first divided into two circulating solvents, which are subjected to the internal circulation and the external circulation respectively, the pressurized solvent obtained is returned and mixed into the alkane solvent for the dissolution, and the obtained alkane-rich stream repeats the above operation, that is, dissolution-internal circulation and external circulation-dissolution...

[0058] In the present invention, during the solvent circulation dissolution process, the dissolution, internal circulation and external circulation can be combined arbitrarily, and the combination methods include but are not limited to the following: dissolution-internal circulation and external circulation, dissolution-internal circulation-external circulation, dissolution-external circulation-inner circulation, dissolution-dissolution internal circulation-dissolution-external circulation, dissolution-external circulation-dissolution-internal circulation.

[0059] In some embodiments of the present invention, preferably, during each solvent circulation dissolution process, the dissolution time t1 is selected from 2-30 hours, preferably 4-24 hours; the internal circulation time t2 is selected from 2-18 hours, preferably 3-15 hours; the external circulation time t3 is selected from 2-18 hours, preferably 3-15 hours.

[0060] In some embodiments of the present invention, it is further preferred that during the activity recovery process, the total time T1 of the solvent circulation dissolution is selected from 30-330 hours, preferably 50-270 hours. The total time T1 of the solvent circulation dissolution includes the sum of the time of multiple solvent circulation dissolutions, and the time of each solvent circulation solvent = dissolution time t1 + internal circulation time t2 and / or external circulation time t3.

[0061] In the present invention, the dissolution is to contact the alkane solvent and the active metal catalyst and soak and dissolve them to obtain an alkane-rich stream containing heavy substances. In the present invention, the heavy substances of the active metal catalyst are selected from sintering products or reaction by-products, for example, oligomerization by-products such as propylene trimers and tetramers.

[0062] 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. In the present invention, pressure refers to gauge pressure.

[0063] In some embodiments of the present invention, preferably, the circulation ratio of the internal circulation and the external circulation is independently 0-100, preferably 1-50, and the circulation ratio refers to the volume ratio of the alkane-rich stream and the active metal catalyst calculated on the basis of the alkane solvent.

[0064] In the present invention, when the circulation ratio of the internal circulation is 0, the dissolution or external circulation is carried out; when the circulation ratio of the external circulation is 0, the dissolution or internal circulation is carried out; 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 of the dissolution are both ≠ 0, the internal circulation and the external circulation are carried out.

[0065] In the present invention, in the initial stage of the solvent circulation dissolution, the circulation ratio may be 0 or not; during the circulation process of the solvent circulation dissolution, the circulation ratio may be 0. When the circulation ratio is 0, the dissolution is carried out, otherwise, the internal circulation and external circulation are carried out.

[0066] In the present invention, the operating condition with a circulation ratio of 0 refers to the internal circulation and external circulation conditions.

[0067] In some embodiments of the present invention, preferably, the total time of the operating condition with a circulation ratio of 0 is 2-30 hours, preferably 4-24 hours.

[0068] In the present invention, by regulating the number and time of the circulation ratio being 0, the activity recovery of the active metal catalyst can be effectively improved, thereby improving the relative activity of the catalyst.

[0069] In the present invention, in order to further remove the heavy substances in the active metal catalyst, preferably, before the dissolution, the alkane solvent is heated to 25-350°C, preferably 25-200°C.

[0070] 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.

[0071] 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.

[0072] In a specific embodiment of the present invention, the alkane solvent is selected from propane, and the water content in the propane is ≤10 ppmv, preferably ≤3 ppmv; the oxygen content is ≤10 ppmv, preferably ≤3 ppmv.

[0073] In some embodiments of the present invention, when the alkane solvent contains olefins, the selectivity of the solvent will be reduced, 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.

[0074] In the present invention, the internal circulation process includes: cooling and pressurizing the alkane-rich stream to obtain a pressurized solvent. Preferably, the temperature of the pressurized solvent is 40-80°C and the pressure is 0.6-5MPa.

[0075] In the present invention, the external circulation is intended to refine the alkane-rich stream 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.

[0076] 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.

[0077] 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.

[0078] In some embodiments of the present invention, preferably, the process of hydrogen circulation cracking includes: contacting the mixed gas with a catalyst and performing the hydrogen circulation cracking, the obtained gas-liquid mixture is sequentially condensed, separated, and pressurized, and the obtained circulating gas is returned and mixed into the mixed gas.

[0079] In some embodiments of the present invention, preferably, the volume content of H2 in the mixed gas is ≥80%, preferably 80-99%.

[0080] In some embodiments of the present invention, preferably, the volume concentration of the ammonia compound in the mixed gas is 1-1000 ppmv.

[0081] In the present invention, the ammonia-containing compound is used as a stabilizer to fix the active center of the catalyst in hydrogen cycle cracking to avoid the aggregation of the active center. Preferably, the ammonia-containing compound is selected from at least one of ammonia, ethanolamine, methylamine, ethylamine, ethylenediamine and n-butylamine, preferably ammonia.

[0082] In some embodiments of the present invention, preferably, the water content in the inert gas is ≤10 ppmv, preferably ≤3 ppmv, and the oxygen content in the inert gas is ≤10 ppmv, preferably ≤3 ppmv.

[0083] In some embodiments of the present invention, preferably, the mixed gas consists of hydrogen, ammonia-containing compounds and inert gas.

[0084] In some embodiments of the present invention, preferably, the conditions for the hydrogen cycle cracking include: temperature of 25-650°C, preferably 300-550°C; pressure of 1-11MPa, preferably 2-6MPa; time T2 of 1-48h, preferably 1-24h; gas-to-agent ratio of 50-1000, preferably 300-800, wherein the gas-to-agent ratio is the volume ratio of the mixed gas and the active metal catalyst in terms of H2.

[0085] In some embodiments of the present invention, preferably, the process of hydrogen cycle cracking includes 0-6 constant temperature sections, the temperature of the constant temperature section is selected from 300-550°C, for example, 300°C, 330°C, 350°C, 400°C, 450°C, 500°C and 550°C, and any value in the range of any two numerical values, and the time of each constant temperature section is selected from 0.1-8h. If multiple constant temperature sections are not set, directly performing activity recovery at a certain reaction temperature will reduce the reaction rate, resulting in unsaturated hydrocarbons in the by-products on the catalyst not being deeply saturated before the cracking reaction occurs, increasing the possibility of coking. Therefore, in the present invention, when the selectivity of the propylene dimerization reaction is not greater than 60% or the conversion rate is greater than 20%, using the temperature and time of the above-mentioned constant temperature section for in-situ activity recovery is more conducive to improving the activity of the catalyst.

[0086] In some embodiments of the present invention, preferably, before the hydrogen cycle cracking, the mixed gas is heated to 25-650°C, preferably 300-550°C.

[0087] In some embodiments of the present invention, preferably, the temperature difference of the hydrogen cycle cracking is 3-50° C., preferably 3-40° C. In the present invention, the temperature difference of the hydrogen cycle cracking refers to the difference between the outlet temperature and the inlet temperature of the hydrogen cycle cracking.

[0088] In the present invention, the gas-liquid mixture is sequentially condensed, separated and pressurized to obtain a circulating gas.

[0089] In the present invention, the condensation is intended to further reduce the temperature of the gas-liquid mixture, separate the cracking reaction products and the circulating hydrogen, and facilitate the recovery of the activity of the active center. Preferably, the condensation temperature is 40-50°C.

[0090] In some embodiments of the present invention, preferably, the conditions for liquid separation include: temperature of 40-50° C.; pressure of 2-6 MPa. The liquid separation is intended to remove the liquid in the gas-liquid mixture to obtain a gas rich in hydrogen and ammonia compounds.

[0091] In some embodiments of the present invention, preferably, when the volume content of H2 in the gas obtained by the liquid separation is less than 80%, part of the gas is discharged as the relaxation gas, and the remaining part is returned after pressurization and mixed into the mixed gas, and H2 is supplemented until the volume content of H2 in the gas is ≥80%; when the volume content of H2 in the gas is ≥80%, and the pressure of the gas is less than (the pressure of the hydrogen cycle cracking-0.5MPa), the gas is returned after pressurization and mixed into the mixed gas, and H2 and / or inert gas are supplemented until the pressure of the gas = (the pressure of the hydrogen cycle cracking-0.5MPa). This arrangement allows the pressure of the cracking reaction to maintain a dynamic balance, thereby improving the activity of the catalyst.

[0092] 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, the method provided in the first aspect is carried out in the device, which comprises: a reactor 1 provided with a catalyst bed, an internal circulation pipeline 01, an external circulation pipeline 02, a hydrogen circulation cracking pipeline 03, an alkane solvent delivery pipeline 04, a reaction raw material delivery pipeline 09 and a reaction product delivery pipeline 010 connected to the reactor 1, and a hydrogen delivery pipeline 05, an inert gas delivery pipeline 06 and an ammonia-containing compound delivery pipeline 07 connected to the hydrogen circulation cracking pipeline 03;

[0093] According to the material flow direction, the inner circulation pipeline 01 is provided with a cooler 2 and a pump 3 in sequence, the outer circulation pipeline 02 is provided with a fractionation tower 5, and the hydrogen circulation cracking pipeline 03 is provided with a condenser 6, a liquid separation tank 7 and a compressor 8 in sequence;

[0094] Among them, the inner circulation pipeline 01, the outer circulation pipeline 02 and the hydrogen circulation cracking pipeline 03 each independently have a working state and a closed state, so that the alkane solvent 11 or the mixed gas 16 respectively contacts the active metal catalyst loaded in the catalyst bed and performs solvent circulation dissolution and hydrogen circulation cracking to obtain a catalyst with restored activity. The mixed gas contains H2, ammonia-containing compounds and inert gases.

[0095] In the present invention, unless otherwise specified, the inlet of the internal circulation pipeline 01 (i.e., the alkane-rich logistics 12) can be connected to the reactor outlet, or can be arranged on the pipeline inside the reactor and extending from the outlet, that is, the inlet of the internal circulation pipeline 01 is selected from 1-4 of the above-mentioned positions; the outlet of the internal circulation pipeline 01 (i.e., the inlet of the pressurized solvent 13) can be connected to the reactor inlet, or can be arranged on the pipeline inside the reactor and extending from the inlet, that is, the outlet of the internal circulation pipeline 01 is selected from 1-4 of the above-mentioned positions.

[0096] Similarly, the inlet of the external circulation pipeline 02 (i.e., the outlet of the alkane-rich logistics 12) can be connected to the reactor outlet, or it can be set on the pipeline inside the reactor and extending from the outlet, that is, the inlet of the external circulation pipeline 02 is selected from 1-4 of the above-mentioned positions; the outlet of the external circulation pipeline 02 (i.e., the inlet of the refined solvent 14) can be connected to the reactor inlet, or it can be set on the pipeline inside the reactor and extending from the inlet, that is, the outlet of the external circulation pipeline 02 is selected from 1-4 of the above-mentioned positions.

[0097] In the present invention, unless otherwise specified, the inlet of the hydrogen circulation cracking line 03 (i.e., the outlet of the gas-liquid mixture 20) can be connected to the reactor outlet, or can be arranged on the pipeline inside the reactor and extending to the outlet, that is, the inlet of the hydrogen circulation cracking line 03 is selected from 1-4 of the above-mentioned positions; the outlet of the hydrogen circulation cracking line 03 (i.e., the inlet of the circulating gas 22) can be connected to the reactor inlet, or can be arranged on the pipeline inside the reactor and extending to the inlet, that is, the outlet of the hydrogen circulation cracking line 03 is selected from 1-4 of the above-mentioned positions.

[0098] In the present invention, unless otherwise specified, the inner circulation pipeline 01, the outer circulation pipeline 02 and the hydrogen circulation cracking pipeline 03 each independently have a working state and a closed state, which means that when the inner circulation pipeline 01 is in a working state, the outer circulation pipeline 02 and the hydrogen circulation cracking pipeline 03 are both in a closed state; when the outer circulation pipeline 02 is in a working state, the inner circulation pipeline 01 and the hydrogen circulation cracking pipeline 03 are both in a closed state; when the hydrogen circulation cracking pipeline 03 is in a working state, the inner circulation pipeline 01 and the outer circulation pipeline 02 are both in a closed state.

[0099] In the present invention, similarly, the reaction raw material delivery pipeline 09 and the reaction product delivery pipeline 010 also independently have a working state and a closed state; the reaction raw material delivery pipeline 09 is used to add the reaction raw material 24 to the reactor 1; the reaction product delivery pipeline 010 is used to draw out the reaction product 25 from the reactor 1.

[0100] In the present invention, based on the quantitative analysis of the reaction product 25 at any stage, the conversion rate of the reaction product 25 at any stage is obtained, and further the activity of the catalyst at any stage is obtained.

[0101] In a specific embodiment of the present invention, Figure 1As shown, when the inner circulation pipeline 01 is in working state, and the outer circulation pipeline 02 and the hydrogen circulation cracking pipeline 03 are both in closed state, the alkane solvent 11 contacts with the active metal catalyst and dissolves, the obtained alkane-rich stream 12 enters the cooler 2 for cooling, the obtained stream enters the pump 3 for pressurization, and the obtained pressurized solvent 13 returns to the reactor 1 for the dissolution; the inner circulation pipeline 01 is closed, the outer circulation pipeline 02 is opened, the obtained alkane-rich stream 12 enters the fractionation tower 5 for refining, and the obtained refined alkane 14 returns to the reactor 1 for dissolution; Repeat the above internal and external circulations; open the hydrogen circulation cracking pipeline 03, and close the internal circulation pipeline 01 and the external circulation pipeline 02, so that the mixed gas 16 containing hydrogen 17, ammonia compounds 19 and inert gas 18 is in contact with the catalyst after solvent circulation dissolution and undergoes hydrogen circulation cracking, the obtained gas-liquid mixture 20 enters the condenser 6 for condensation, the obtained logistics enters the liquid separator 7 for liquid separation, the obtained gas 21 enters the compressor 8 for pressurization, the obtained circulating gas 22 returns to and enters the reactor 1, and the above operation is repeated to obtain a catalyst with restored activity.

[0102] In the present invention, preferably, Figure 1 As shown, the reactor 1 is selected from a fixed bed reactor.

[0103] In the present invention, preferably, Figure 1 As shown, the first temperature measuring point T1 and the second temperature measuring point T2 connecting the top and the bottom of the catalyst bed in the reactor 1 are used to detect the temperature difference of the hydrogen cycle cracking, and T1 is used to detect the temperature of the catalyst bed during the dissolution.

[0104] In the present invention, preferably, Figure 1 As shown, the device further comprises: a first gas detection point A1 connected to the top of the reactor 1 for detecting the volume concentration of H 2 and ammonia-containing compounds in the mixed gas 16 .

[0105] In the present invention, preferably, Figure 1 As shown, the device also includes: according to the material flow direction, a second gas detection point A2 and a purge gas flow control instrument FC are sequentially arranged on the pipeline connecting the separator tank 7 and the compressor 8, which are used to detect the volume content of H2 in the gas 21. When the volume content of H2 in the gas 21 is ≥80%, the gas 21 is returned after pressurization and enters the reactor 1; when the volume content of H2 in the gas 21 is <80%, part of the gas 21 is discharged as purge gas, and the remaining part of the gas is returned after pressurization and enters the reactor 1, and H2 is supplemented until the volume content of H2 in the gas 21 is ≥80%.

[0106] In the present invention, preferably, Figure 1As shown, the device also includes: a pressure control instrument PC is provided on the pipeline connecting the hydrogen delivery pipeline 05, the inert gas delivery pipeline 06 and the top of the separator 7, which is used to regulate the pressure and the relaxation gas flow rate of the reactor 1. When the volume content of H2 in the gas 21 is less than 80%, part of the gas 21 is discharged as relaxation gas, and the discharge amount is controlled. The remaining part of the gas is pressurized and supplemented with H2 until the pressure of the gas 21 = (the pressure of the hydrogen cycle cracking - 0.5MPa); when the volume content of H2 in the gas 21 is less than 80%, part of the gas 21 is discharged as relaxation gas, and the discharge amount is controlled. When the volume content of H2 in the gas 21 is ≥80% and the pressure of the gas 21 is <(the pressure of the hydrogen cycle cracking - 0.5 MPa), the gas 21 is pressurized and returned to the reactor 1, and hydrogen 17 and / or inert gas 18 are supplemented until the pressure of the gas 21 = (the pressure of the hydrogen cycle cracking - 0.5 MPa); or, when the volume content of H2 in the gas 21 is ≥80%, the pressure of the gas 21 = (the pressure of the hydrogen cycle cracking - 0.5 MPa), the gas 21 is pressurized and returned to the reactor 1.

[0107] In the present invention, preferably, Figure 1 As shown, the device also includes: a heater 4 connected to the internal circulation pipeline 01, the external circulation pipeline 02, the hydrogen circulation cracking pipeline 03, the alkane solvent delivery pipeline 04 and the reactor 1, which is used to return the pressurized solvent 13, the refined solvent 14, the mixed gas 16, and the alkane solvent 11 to the reactor 1 after being heated respectively.

[0108] In the present invention, preferably, Figure 1 As shown, the device further comprises: a first fresh solvent delivery pipeline 08 - i connected to the internal circulation pipeline 01 , for mixing the pressurized solvent 13 and the fresh alkane solvent 23 and returning them to the reactor 1 .

[0109] In the present invention, preferably, Figure 1 As shown, the device further comprises: a second fresh solvent delivery pipeline 08 - ii connected to the external circulation pipeline 02 , for mixing the refined solvent 14 and the fresh alkane solvent 23 and returning them to the reactor 1 .

[0110] According to a particularly preferred embodiment of the present invention, a method for extending the service life of an active metal catalyst online comprises: using an alkane solvent and a mixed gas containing H2, an ammonia compound and an inert gas to respectively restore the activity of the active metal catalyst; wherein the activity restoration comprises: solvent circulation dissolution and hydrogen circulation cracking, and the solvent circulation dissolution comprises dissolution, internal circulation and / or external circulation; wherein, when γ 氢 <γ<γ 溶 , the solvent is circulated and stripped; when γ≤γ 氢, the hydrogen cycle cracking is carried out; when γ ≥ γ 溶 , to react; γ is the activity of the catalyst at any stage, %; γ 氢 is the critical value for the hydrogen cycle cracking, 20%≤γ 氢 ≤60%;γ 溶 The critical value for the solvent circulation stripping is 60% < γ 溶 ≤80%;

[0111] The above method specifically includes the following steps:

[0112] (1) contacting the alkane solvent with the active metal catalyst and performing the solvent circulation stripping, wherein the obtained catalyst after solvent circulation stripping satisfies: γ≥γ 溶 ;

[0113] (2) circulating the solvent to dissolve the catalyst and carry out the reaction until the catalyst satisfies the following conditions: 氢 <γ<γ 溶 , repeat the above step (1);

[0114] (3) When the catalyst satisfies the following conditions after the reaction: γ≤γ 氢 , the hydrogen cycle cracking is carried out, and the catalyst obtained after hydrogen cycle cracking satisfies: γ≥γ 溶 ;

[0115] (4) The hydrogen is circulated and cracked to the catalyst for the reaction until the catalyst satisfies: γ<γ 溶 , to remove the agent.

[0116] The present invention will be described in detail below through examples.

[0117] Fresh active metal catalyst S1, loading amount is 0.1 kg, bulk density is 0.991 g / mL; activity is 100%; active metal is selected from Na and K, the mass ratio of Na and K is 1:2, and the total loading is 5 wt%, and the carrier is selected from potassium carbonate;

[0118] Fresh active metal catalyst S2, loading amount is 0.1kg, bulk density is 0.85g / mL; activity is 82%; active metals are selected from Na and K, the mass ratio of Na and K is 5:1, and the total loading is 2wt%, and the carrier is selected from potassium carbonate.

[0119] Example 1

[0120] Devices such as Figure 1As shown, the device includes: a reactor 1 provided with a catalyst bed, an inner circulation pipeline 01, an outer circulation pipeline 02, a hydrogen circulation cracking pipeline 03, an alkane solvent delivery pipeline 04, a reaction raw material delivery pipeline 09 and a reaction product delivery pipeline 010 connected to the reactor 1, and a hydrogen delivery pipeline 05, an inert gas delivery pipeline 06 and an ammonia-containing compound delivery pipeline 07 connected to the hydrogen circulation cracking pipeline 03; wherein, according to the material flow direction, a cooler 2 and a pump 3 are sequentially arranged on the inner circulation pipeline 01, a fractionation tower 5 is arranged on the outer circulation pipeline 02, and a condenser 6, a liquid separator 7 and a compressor 8 are sequentially arranged on the hydrogen circulation cracking pipeline 03;

[0121] The device also includes: a first temperature measuring point T1, a second temperature measuring point T2, a first gas detection point A1, a second gas detection point A2, a purge gas flow control instrument FC, a pressure control instrument PC and a heater 4;

[0122] The reactor 1 is selected from a fixed bed reactor filled with fresh active metal catalyst S1.

[0123] Methods include:

[0124] (1) The fresh active metal catalyst S1 was heated at a mass space velocity of 1 h -1 After 3000 h of reaction, the activity of the catalyst dropped to 70% (i.e., satisfying γ 氢 <γ<γ 溶 ), the activity of the catalyst is restored by solvent circulation dissolution, the solvent circulation dissolution method is selected from dissolution-internal circulation-external circulation, that is,

[0125] After the alkane solvent (propane, water content of 2 ppmv, oxygen content of 2 ppmv, olefin content of 0.5 volume %) is heated to 200°C, it is contacted with the above catalyst and dissolved (temperature of 90°C, time t1 of 8h), the obtained alkane-rich stream is internally circulated (circulation ratio of 20, time t2 of 8h), the above alkane-rich stream is successively cooled and pressurized, the obtained pressurized solvent (temperature of 60°C, pressure of 3MPa) is externally circulated after passing through reactor 1 (circulation ratio of 20, time t3 of 4h), the above stream is refined, the obtained refined solvent is returned and mixed with the above alkane solvent, and the catalyst after the first solvent circulation stripping satisfies γ≥γ 溶 ,

[0126] The total time of the first solvent cycle stripping is 20 hours.

[0127] (2) After the catalyst was subjected to the first solvent cycle stripping reaction for 2160 hours, the catalyst activity dropped to 70% again, and the above solvent cycle stripping method and operating conditions were repeated to restore the catalyst activity;

[0128] After the catalyst activity was restored by the solvent circulation stripping method for the n=5th time, the activity of the catalyst decreased to 50% after the reaction for 300 hours (t<15 days), and the activity of the catalyst was restored by the hydrogen circulation cracking method;

[0129] (3) A mixed gas containing nitrogen (water content of 2 ppmv, oxygen content of 2 ppmv), H2 and ammonia (H2 volume content of 90%, ammonia concentration of 500 ppmv) was heated to 550°C, contacted with the above catalyst and subjected to hydrogen cycle cracking (temperature of 550°C, pressure of 2.5 MPa, gas-to-agent ratio of 400). The obtained gas-liquid mixture was condensed, separated and pressurized in turn. The obtained circulating gas (temperature of 45°C, pressure of 2 MPa, H2 volume content of 90%) was returned and mixed with the above mixed gas. After the hydrogen cycle cracking T2 was selected from 20h, the activity of the catalyst after hydrogen cycle cracking reached more than 80% (i.e., satisfying γ ≥ γ 溶 );

[0130] (4) The above hydrogen cycle cracking catalyst was reacted for 720 hours until the catalyst activity dropped below 70% (i.e., γ<γ 溶 ), the catalyst life cycle ends and the catalyst is unloaded.

[0131] During the entire service life of the catalyst, the total raw material processing capacity is 800kg.

[0132] Example 2

[0133] According to the device of embodiment 1;

[0134] According to the method of Example 1, the difference is that

[0135] In step (2), n=6 solvent cycles are used for dissolution.

[0136] The solvent circulation dissolution method for the 1st to 4th time is the same as that in Example 1;

[0137] After the catalyst was restored to activity by the fifth solvent cycle dissolution, the catalyst was put into reaction again for 280 hours, and the activity of the catalyst dropped to 70%. After the catalyst was restored to activity by the sixth solvent cycle dissolution and operation, the catalyst was put into reaction again for 50 hours, when the activity of the catalyst dropped to 50% (i.e., satisfying: γ≤γ 氢 ), using hydrogen cycle cracking to restore the activity of the catalyst;

[0138] Step (3), same as in Example 1;

[0139] Step (4), the above hydrogen cycle cracking catalyst is reacted for 720 hours until the catalyst activity drops below 70% (i.e., γ<γ 溶 ), the catalyst life cycle ends and the catalyst is unloaded.

[0140] Example 3

[0141] According to the device of embodiment 1;

[0142] According to the method of Example 1, the difference is that

[0143] n = 3 solvent cycles are used for dissolution, and m = 1 hydrogen cycle is used for cracking;

[0144] The rest of the conditions are the same.

[0145] Example 4

[0146] According to the device of embodiment 1;

[0147] According to the method of Example 1, the difference is that

[0148] In step (3), during the hydrogen cycle cracking cycle, the mixed gas is heated to 350° C.; the other conditions are the same.

[0149] Example 5

[0150] According to the device of embodiment 1;

[0151] According to the method of Example 1, the difference is that

[0152] In step (3), during the hydrogen cycle cracking cycle, the volume concentration of ammonia in the mixed gas is replaced to 5000 ppmv;

[0153] The rest of the conditions are the same.

[0154] Comparative Example 1

[0155] The device according to Example 1 is different in that:

[0156] The device does not include: hydrogen cycle cracking pipeline 03, hydrogen delivery pipeline 05, inert gas delivery pipeline 06, ammonia compound delivery pipeline 07, condenser 6, liquid separator 7 and compressor 8, as well as the second gas detection point A2, purge gas flow control instrument FC, and pressure control instrument PC;

[0157] According to the method of Example 1, the difference is that

[0158] Only 5 solvent cycles were performed without hydrogen cycle cracking, i.e.

[0159] The catalyst after the reaction in step (2) is directly subjected to a catalyst removal treatment.

[0160] Comparative Example 2

[0161] The device according to Example 1 is different in that:

[0162] The device does not include: an internal circulation pipeline 01, an external circulation pipeline 02, an alkane solvent delivery pipeline 04, a cooler 2, a pump 3, a distillation tower 5, and a first gas detection point A1.

[0163] According to the method of Example 1, the difference is that

[0164] Instead of performing 5 solvent cycle stripping, hydrogen cycle cracking was performed, i.e.,

[0165] After the fresh active metal catalyst S1 reacts for 3600 hours, its activity drops to 50%, and then hydrogen cycle cracking is performed. The catalyst obtained after hydrogen cycle cracking is reacted for 2400 hours until the catalyst activity drops below 70% (i.e., γ<γ 溶 ), the catalyst life cycle ends and the catalyst is unloaded.

[0166] Comparative Example 3

[0167] The device according to Example 1 is different in that:

[0168] The reactor 1 is selected from a fixed bed reactor filled with fresh active metal catalyst S2.

[0169] According to the method of Example 1, the difference is that

[0170] In step (1), the above-mentioned fresh active metal catalyst S2 is used, because the activity of the active metal catalyst S2 is lower than that of the catalyst S1 in Example 1;

[0171] The solvent was eluted three times and finally cleaved once with hydrogen, and the other conditions were the same.

[0172] Table 1

[0173]

[0174]

[0175] Note: Service life* = total raw material processing volume / raw material processing volume per unit time. The raw material processing volume per unit time in Examples 1-5 and Comparative Examples 1-3 is 0.1 kg / h.

[0176] Table 1

[0177]

[0178]

[0179] Note: Service life* = total raw material processing volume / raw material processing volume per unit time. The raw material processing volume per unit time in Examples 1-5 and Comparative Examples 1-3 is 0.1 kg / h.

[0180] It can be seen from the results in Table 1 that, compared with Comparative Examples 1-3, Example 1, which adopts the method provided by the present invention, first performs multiple solvent cycle dissolution and finally performs hydrogen cycle cracking during the use of the active metal catalyst, has a larger total raw material processing capacity, extends the service life of the catalyst, and improves the in-situ activity recovery significantly better.

[0181] At the same time, compared with Example 1, when the number of solvent circulation dissolution times in Example 2 exceeds a certain limit, continuing to increase the number of solvent circulation dissolution times has little effect on extending the service life of the catalyst, but instead increases the time, investment and energy consumption for catalyst activity recovery.

[0182] Compared with Example 1, the quality of the fresh catalyst used in Comparative Example 3, that is, the different initial activities, affects the upper limit of the solvent circulation and stripping times, thereby further affecting the service life of the catalyst.

[0183] Compared with Examples 4-5, Example 1 changes the process parameters of hydrogen cycle cracking and has a larger total raw material processing capacity.

[0184] 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 extending the service life of an active metal catalyst online, characterized in that: The method comprises: using an alkane solvent and a mixed gas containing H2, an ammonia compound and an inert gas to respectively restore the activity of an active metal catalyst; wherein the activity recovery comprises: solvent circulation dissolution and hydrogen circulation cracking, and the solvent circulation dissolution comprises dissolution, internal circulation and / or external circulation; Among them, when γ 氢 <γ<γ 溶 , the solvent is circulated and stripped; when γ≤γ 氢 , the hydrogen cycle cracking is carried out; when γ ≥ γ 溶 , to react; γ is the activity of the catalyst at any stage, %; γ 氢 is the critical value for the hydrogen cycle cracking, γ 氢 ≤60%;γ 溶 The critical value for the solvent circulation stripping is 60% < γ 溶 ≤80%.

2. The method according to claim 1, wherein: The method comprises the following steps: (1) contacting the alkane solvent with the active metal catalyst and performing the solvent circulation stripping, wherein the obtained catalyst after solvent circulation stripping satisfies: γ≥γ 溶 ; (2) circulating the solvent to dissolve the catalyst and perform the reaction until the catalyst satisfies the following conditions: 氢 <γ<γ 溶 , repeat the above step (1); (3) When the catalyst satisfies the following conditions after the reaction: γ≤γ 氢 , the hydrogen cycle cracking is carried out, and the catalyst obtained after hydrogen cycle cracking satisfies: γ≥γ 溶 ; (4) The hydrogen is circulated and cracked to the catalyst for the reaction until the catalyst after the reaction satisfies: γ < γ 溶 , to unload the agent; and / or, 20% ≤ γ 氢 ≤60%; And / or, the number of operations of the solvent circulation stripping is n≥1 times, and n is preferably selected from 1 to 5 times; And / or, the number of operations m of the hydrogen cycle cracking is selected from 1; And / or, after the (n-1)th (1≤n≤5) solvent circulation dissolution, the time for the catalyst to carry out the reaction after the solvent circulation dissolution is greater than 15 days; after the nth (1≤n≤5) solvent circulation dissolution, the time for the catalyst to carry out the reaction after the solvent circulation dissolution is ≤15 days.

3. The method according to claim 1 or 2, wherein: The dispersion recovery rate of the active metal in the catalyst after hydrogen cycle cracking is ≥75%, preferably 80-99%, wherein the dispersion recovery rate = the dispersion of the active metal in the catalyst after hydrogen cycle cracking / the dispersion of the active metal in the fresh active metal catalyst; and / or, the activity of the active metal catalyst is ≤80%, preferably 60-80%; and / or, 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 active metal catalyst is selected from the catalyst for preparing 4-methyl-1-pentene by propylene dimerization.

4. The method according to any one of claims 1 to 3, wherein: The solvent circulation stripping process includes: contacting the alkane solvent with an active metal catalyst and performing the dissolution, and the obtained alkane-rich stream performs the internal circulation and / or external circulation; wherein the internal circulation process includes: sequentially cooling and pressurizing the alkane-rich stream, and the pressurized solvent obtained is returned and mixed into the alkane solvent; the external circulation process includes: refining the alkane-rich stream, and the refined solvent obtained is returned and mixed into the alkane solvent; And / or, the solvent circulation and dissolution method is selected from dissolution-internal circulation and external circulation, dissolution-internal circulation-external circulation, dissolution-external circulation-inner circulation, dissolution-dissolution internal circulation-dissolution-external circulation, and dissolution-external circulation-dissolution-internal circulation.

5. The method according to any one of claims 1 to 4, wherein: During each solvent circulation and dissolution process, the dissolution time t1 is selected from 2-30 hours, preferably 4-24 hours; the inner circulation time t2 is selected from 2-18 hours, preferably 3-15 hours; the outer circulation time t3 is selected from 2-18 hours, preferably 3-15 hours; And / or, during the activity recovery process, the total time T1 of the solvent circulation dissolution is selected from 30-330h, preferably 50-270h; And / or, the dissolution conditions include: temperature of 25-350°C, preferably 25-200°C; pressure of 0.5-11MPa, preferably 0.5-5MPa; and / or, the circulation ratio of the internal circulation and the external circulation is independently 0-100, preferably 1-50, and the circulation ratio refers to the volume ratio of the alkane-rich stream and the active metal catalyst calculated on the basis of the alkane solvent; Preferably, the total time of the operating condition with a circulation ratio of 0 is 2-30 hours, preferably 4-24 hours; And / or, before the dissolving, the alkane solvent is heated to 25-350°C, preferably 25-200°C.

6. The method according to any one of claims 1 to 5, 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 %.

7. The method according to any one of claims 1 to 6, wherein: The process of hydrogen cycle cracking comprises: contacting the mixed gas with a catalyst and performing the hydrogen cycle cracking, condensing, separating and pressurizing the obtained gas-liquid mixture in sequence, and returning the obtained cycle gas to be mixed with the mixed gas; And / or, the volume content of H2 in the mixed gas is ≥80%, preferably 80-99%; And / or, the volume concentration of the ammonia compound in the mixed gas is 1-1000 ppmv; and / or, the ammonia-containing compound is at least one selected from ammonia, ethanolamine, methylamine, ethylamine, ethylenediamine and n-butylamine, preferably ammonia; And / or, the water content in the inert gas is ≤10ppmv, preferably ≤3ppmv, and the oxygen content is ≤10ppmv, preferably ≤3ppmv; And / or, the mixed gas consists of H2, ammonia-containing compounds and inert gas.

8. The method according to any one of claims 1 to 7, wherein: The conditions of the hydrogen cycle cracking include: temperature of 25-650°C, preferably 300-550°C; pressure of 1-11MPa, preferably 2-6MPa; time T2 of 1-48h, preferably 1-24h; gas-to-agent ratio of 50-1000, preferably 300-800, wherein the gas-to-agent ratio is the volume ratio of the mixed gas and the active metal catalyst in terms of H2; and / or, the temperature difference of the hydrogen cycle cracking is 3-50°C, preferably 3-40°C; And / or, the hydrogen cycle cracking process includes 0-6 constant temperature sections, the temperature of the constant temperature section is selected from 300-550° C., and the time of each constant temperature section is selected from 0.1-8h; And / or, before the hydrogen cyclic cracking, the mixed gas is heated to 25-650°C, preferably 300-550°C.

9. The method according to claim 7 or 8, wherein: The condensation temperature is 40-50°C; And / or, the conditions for liquid separation include: temperature of 40-50°C; pressure of 2-6MPa; And / or, when the volume content of H2 in the gas obtained by the separation is less than 80%, part of the gas is discharged as relaxation gas, and the remaining part is returned after the pressurization and mixed into the mixed gas, and H2 is supplemented until the volume content of H2 in the gas is ≥80%; when the volume content of H2 in the gas is ≥80%, and the pressure of the gas is less than (the pressure of the hydrogen cycle cracking - 0.5 MPa), the gas is returned after the pressurization and mixed into the mixed gas, and H2 and / or inert gas is supplemented until the pressure of the gas = (the pressure of the hydrogen cycle cracking - 0.5 MPa).

10. An online device for extending the service life of an active metal catalyst, characterized in that: The method according to any one of claims 1 to 9 is carried out in the device, which comprises: a reactor (1) provided with a catalyst bed, an internal circulation pipeline (01), an external circulation pipeline (02), a hydrogen circulation cracking pipeline (03), an alkane solvent delivery pipeline (04), a reaction raw material delivery pipeline (09) and a reaction product delivery pipeline (010) connected to the reactor (1), and a hydrogen delivery pipeline (05), an inert gas delivery pipeline (06) and an ammonia-containing compound delivery pipeline (07) connected to the hydrogen circulation cracking pipeline (03); Wherein, according to the material flow direction, the inner circulation pipeline (01) is provided with a cooler (2) and a pump (3) in sequence, the outer circulation pipeline (02) is provided with a fractionation tower (5), and the hydrogen circulation cracking pipeline (03) is provided with a condenser (6), a liquid separation tank (7) and a compressor (8) in sequence; The inner circulation pipeline (01), the outer circulation pipeline (02) and the hydrogen circulation cracking pipeline (03) each independently have a working state and a closed state, so that the alkane solvent (11) or the mixed gas (16) respectively contacts the active metal catalyst loaded in the catalyst bed and performs solvent circulation dissolution and hydrogen circulation cracking, and the mixed gas contains H2, ammonia-containing compounds and inert gases.

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 first temperature measuring point (T1) and a second temperature measuring point (T2) connected to the top and the bottom of the catalyst bed in the reactor (1); And / or, the device further comprises: a first gas detection point (A1) connected to the top of the reactor (1); And / or, the device further comprises: a second gas detection point (A2) and a purge gas flow control instrument (FC) are sequentially arranged on a pipeline connecting the liquid separation tank (7) and the compressor (8) according to the material flow direction; And / or, the device further comprises: a pressure control instrument (PC) is provided on the pipeline connecting the hydrogen delivery pipeline (05), the inert gas delivery pipeline (06) and the top of the liquid separation tank (7); And / or, the device further comprises: a heater (4) connecting the inner circulation pipeline (01), the outer circulation pipeline (02), the hydrogen circulation cracking pipeline (03), the alkane solvent delivery pipeline (04) and the reactor (1); And / or, the device further comprises: a first fresh solvent delivery pipeline (08-i) connected to the internal circulation pipeline (01), for mixing the pressurized solvent (13) and the fresh alkane solvent (23) and returning them to the reactor (1); And / or, the device further comprises: a second fresh solvent delivery pipeline (08-ii) connected to the external circulation pipeline (02), for mixing the refined solvent (14) and the fresh alkane solvent (23) and returning the mixture to the reactor (1).

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