CN115254120B

CN115254120B - Pre-reduction type high nickel content hydrogenation catalyst and preparation method and application thereof

Info

Publication number: CN115254120B
Application number: CN202110479908.5A
Authority: CN
Inventors: 孙霞; 吴玉; 侯朝鹏; 夏国富; 张荣俊; 徐润; 顾畅
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2021-04-30
Filing date: 2021-04-30
Publication date: 2023-10-10
Anticipated expiration: 2041-04-30
Also published as: CN115254120A

Abstract

The invention relates to the technical field of pretreatment of catalysts, in particular to a pre-reduced high-nickel-content hydrogenation catalyst, a preparation method and application thereof, wherein in the pre-reduced high-nickel-content hydrogenation catalyst, the total amount of the catalyst is taken as a reference, the nickel content is 40-75% by weight in terms of oxide, the number of active centers of the catalyst after re-reduction treatment is 0.1-0.5mmol hydrogen/g catalyst, and the re-reduction treatment conditions comprise: the temperature was 200℃for 2 hours, the reducing atmosphere was a hydrogen and argon-containing atmosphere having a hydrogen concentration of 10% by volume, and the gas-to-gas ratio was 15000. The pre-reduced hydrogenation catalyst with high nickel content provided by the invention has proper reduction degree, more active centers, good reactivation performance and good stability.

Description

Pre-reduction type high nickel content hydrogenation catalyst and preparation method and application thereof

Technical Field

The invention relates to the technical field of pretreatment of catalysts, in particular to a pre-reduced hydrogenation catalyst with high nickel content, a preparation method and application thereof.

Background

The HPPO process uses hydrogen peroxide to epoxidize propylene to produce propylene oxide, and the reaction of propylene with hydrogen peroxide is carried out in a methanol solvent. Some of the byproducts formed in the HPPO process and recycled methanol can form compounds with hydrogen peroxide, such as formaldehyde, acetaldehyde, propylene glycol, hydroxyacetone, formic acid, acetic acid, methyl formate, methyl acetate, acetals, etc., which can accumulate in the recycled methanol and be difficult to separate by distillation, directly affecting the purity of the PO product. The catalyst can remove most by-product compounds by catalytic hydrogenation, and is prepared from Pd, pt, rh, ru, ir, os, ni metal, activated carbon or porous metal oxide such as activated carbon and Al ₂ O ₃ 、SiO ₂ Zeolite, aluminosilicate, tiO ₂ 、ZrO ₂ Etc.

The nickel catalyst has wide application in hydrogenation reaction due to relatively low price and high hydrogenation activity. The application fields comprise oil product hydrogenation, vegetable oil hydrogenation, CO hydrogenation, olefin hydrogenation, alkyne hydrogenation, aromatic hydrocarbon hydrogenation, nitrobenzene hydrogenation, natural chlorophyll hydrogenation reaction and the like. In the hydrogenation of HPPO recycle methanol, the catalyst is required to have high hydrogenation performance under low temperature conditions (e.g. below 120 ℃).

In HPPO recycle methanol hydrogenation, the catalyst is one of the key core technologies. The metal component of the catalyst is usually prepared as an oxide, and the catalyst is only subjected to reduction treatment to render it catalytically active. The reduction pretreatment conditions of the catalyst are reasonably selected, so that the catalyst has higher activity in the reaction.

The catalyst reduction can adopt external pre-reduction or internal reduction, generally, the operation difficulty of carrying out the catalyst reduction in a reaction device is high, and once the operation is improper, the catalyst is caused to sinter due to the flying temperature, so that the immeasurable economic loss is caused. The catalyst pre-reduction technology has a plurality of advantages, and the external pre-reduction technology not only can improve the utilization rate of the reducing agent, reduce the consumption of the reducing agent and the starting cost, but also shortens the starting period and finally increases the economic benefit of enterprises. The catalyst after pre-reduction is filled into a reactor and then is subjected to low-temperature reactivation for use. In particular, the method is suitable for the condition that the reduction temperature is obviously higher than the subsequent reaction temperature, and the reactor does not need to be specially processed due to the reduction reaction.

The same catalyst is different in reduction and passivation treatment modes, and the reaction activity and selectivity are also different in influence. For different catalysts, different reduction and passivation treatments are generally used to achieve better activity and selectivity.

The defects of the prior art are that the reduction time of the catalyst is longer, the hydrogen consumption is large, and the like, so that the catalyst has long processing period, high cost, and the like, and the reduction passivation efficiency of the catalyst is affected. The known passivation methods require a long passivation time and the resulting catalyst passivation is not uniform.

In addition, there are few reports on the reductive passivation of high nickel metal content catalysts. There is no pre-reduction method for HPPO recycle methanol hydrogenation catalyst with high nickel content (nickel content of HPPO recycle methanol hydrogenation catalyst is 50-75% of HPPO recycle methanol hydrogenation catalyst weight calculated as nickel oxide) in the prior art. The HPPO recycle methanol hydrogenation reaction temperature is low, the reactor does not need to be specially processed due to the reduction reaction, and in order to reduce investment, a pre-reduction method for the HPPO recycle methanol hydrogenation catalyst is needed in the industry.

Disclosure of Invention

The invention aims to overcome the defects of low catalytic activity, long pre-reduction time, large hydrogen consumption and low reduction passivation efficiency of a pre-reduction method of a pre-reduction catalyst in the prior art, and provides a pre-reduction high-nickel-content hydrogenation catalyst, a preparation method and application thereof.

The inventor of the invention researches and discovers that in the prior art, in order to ensure that active metals are better dispersed, the aggregation of the metals under the high-temperature condition is reduced, the high-temperature stability is improved, and when preparing an oxidation-state catalyst, high-temperature roasting is often selected, so that the nickel-aluminum spinel content in the catalyst is higher, and the nickel-aluminum spinel is harder to reduce, so that the reduction step needs very high reduction temperature, long reduction time, large hydrogen consumption and low reduction efficiency; however, too long a reduction time and/or too high a reduction temperature can easily lead to metal grain growth, affecting the number of active centers. Therefore, in order to obtain a catalyst with a large number of active sites for a hydrogenation catalyst with a high nickel content used under low temperature conditions, a method for rapidly reducing the metal component in the catalyst at a relatively low temperature in a relatively short time is highly demanded. Based on this, the inventors completed the present invention.

In order to achieve the above object, the first aspect of the present invention provides a pre-reduced high nickel content hydrogenation catalyst having a nickel content of 40 to 75 wt% on an oxide basis based on the total amount of the catalyst, the catalyst having an active center number of 0.1 to 0.5mmol hydrogen per g of catalyst after a re-reduction treatment, the re-reduction treatment conditions comprising: the temperature was 200℃for 2 hours, the reducing atmosphere was a hydrogen and argon-containing atmosphere having a hydrogen concentration of 10% by volume, and the gas-to-gas ratio was 15000.

The second aspect of the invention provides a method for preparing a pre-reduced high nickel content hydrogenation catalyst, the method comprising:

(1) Reducing the high nickel content oxidation state hydrogenation catalyst in a reducing atmosphere; the reduction includes: stage 1) raising the temperature to 160-300 ℃ at a heating rate of 60-150 ℃/hour, and preserving the temperature for 0.5-8 hours; stage 2) raising the temperature to 320-520 ℃ at a heating rate of 50-150 ℃/hour, and preserving the temperature for 0.3-8 hours;

(2) And (3) reducing the temperature of the catalyst obtained by the reduction in the step (1) to below 60 ℃, and passivating the catalyst obtained by the reduction in the step (1), wherein the passivation comprises the following steps: continuously introducing oxygen-containing gas below 60 ℃ and controlling the passivation temperature to be not higher than 80 ℃; wherein the oxygen concentration of the oxygen-containing gas is continuously increased;

Wherein, in the high nickel content oxidation state hydrogenation catalyst, the total amount of the catalyst is taken as a reference, and the nickel content is 40-75 weight percent in terms of oxide.

In a third aspect, the present invention provides a pre-reduced high nickel hydrogenation catalyst prepared by the preparation method described in the second aspect.

In a fourth aspect, the present invention provides the use of a pre-reduced high nickel content hydrogenation catalyst according to the first or third aspect in an HPPO recycle methanol hydrogenation reaction.

Through the technical scheme, the pre-reduced hydrogenation catalyst with high nickel content provided by the invention has proper reduction degree, has a plurality of active centers, good reactivation performance and good stability, and can restore activity only under lower re-reduction conditions (for example, the re-reduction temperature is 200 ℃ and the time is 2 hours). While the prereduced catalysts of the prior art are less likely to be subjected to re-reduction conditions, it can be seen from the description of the passivation conditions that control of the passivation conditions is more general and typically requires more than 2 hours of re-reduction at temperatures above 250 ℃.

According to the preparation method provided by the invention, through the specific reduction process and the specific passivation process, the metal components in the catalyst can be reduced better and more rapidly under the conditions of lower temperature and shorter time, and the performance of the prepared pre-reduced hydrogenation catalyst with high nickel content is improved together by matching with the subsequent moderate passivation, and the reduction passivation efficiency is high. The prepared pre-reduced hydrogenation catalyst with high nickel content has more active centers, and can be recovered into a hydrogenation catalyst with higher active center number only at a lower re-reduction temperature before application.

The pre-reduced hydrogenation catalyst with high nickel content can be recovered to a hydrogenation catalyst with higher active center number at a lower temperature, can be applied to various hydrogenation reactions, reduces the start-up time and reduces the investment of reduction equipment. The pre-reduction type high nickel content hydrogenation catalyst is particularly suitable for HPPO circulating methanol hydrogenation reaction, the HPPO circulating methanol hydrogenation reaction temperature is low, and the reactor does not need to be specially processed due to re-reduction reaction.

Detailed Description

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

In the present invention, the gas-to-gas ratio refers to the ratio of the volume of gas passing through the catalyst bed to the volume of catalyst per hour, the gas of the gas-to-gas ratio in the reduction process (or the re-reduction process) refers to the reducing gas (i.e., the hydrogen-containing gas), and the gas of the gas-to-gas ratio in the passivation process refers to the passivation gas (i.e., the oxygen-containing passivation gas, also referred to as the oxygen-containing gas).

In the present invention, the reduction of the catalyst after passivation is referred to as "re-reduction", and the reduction performed before passivation is referred to as "reduction".

According to a first aspect of the present invention, there is provided a pre-reduced high nickel content hydrogenation catalyst having a nickel content of 40 to 75 wt% as oxide based on the total amount of the catalyst, the catalyst having an active center number of 0.1 to 0.5mmol hydrogen per g of catalyst after a re-reduction treatment, the re-reduction treatment conditions comprising: the temperature was 200℃for 2 hours, the reducing atmosphere was a hydrogen and argon-containing atmosphere having a hydrogen concentration of 10% by volume, and the gas-to-gas ratio was 15000.

In the invention, the number of the active centers is H on an Autochem2950 full-automatic high-pressure chemical adsorption instrument manufactured by Micromeritics company of America ₂ Programmed temperature desorption (H) ₂ -TPD) test, the test method is: weighing 0.2000g of 40-60 mesh sample, and firstly performing reduction activation under the following conditions: h with hydrogen content of 10 vol% ₂ Ar mixed gas, the flow rate of the mixed gas is 50mL/min, and the temperature is increased to 200 ℃ at the heating rate of 10 ℃ per minute for reduction for 2h. H in the reduced catalyst with 10% by volume of hydrogen ₂ Cooling in Ar mixed gas, switching to Ar gas for purging after the temperature is reduced to 55 ℃, enabling Ar flow to be 20mL/min until a base line is stable, and then carrying out H ₂ TPD experiments. H ₂ The experimental conditions and procedure for TPD were: the carrier gas is Ar, the carrier gas flow is 20mL/min, the heating rate is 10 ℃/min, the final temperature is 400 ℃, and the Thermal Conductivity Detector (TCD) detects signals to obtain a TPD curve.

Preferably, the catalyst has an active site number of 0.1 to 0.4mmol hydrogen per g catalyst after the re-reduction treatment, more preferably 0.15 to 0.4mmol hydrogen per g catalyst.

According to the present invention, preferably, the catalyst has a TPR curve in which the peak value of the largest area low temperature reduction peak corresponds to a temperature of 130 to 280 ℃, more preferably 140 to 230 ℃. The pre-reduced hydrogenation catalyst with high nickel content provided by the invention has good reproducibility, can recover activity only by re-reduction under a lower re-reduction treatment condition, and has a plurality of active centers.

In the invention, the TPR (namely temperature programmed reduction) characterization is carried out by an Autochem2950 full-automatic high-pressure chemical adsorption instrument manufactured by Micromerics corporation of America, and the test conditions are as follows: 0.20g of sample is dehydrated for 1 hour by heating the sample to 120 ℃ at a heating rate of 10 ℃/min under 50mL/min Ar air flow, and TPR experiment is carried out after the temperature is reduced to 50 ℃, wherein the experimental conditions and procedures of the TPR are as follows: the reducing gas is H with the hydrogen content of 10 volume percent ₂ Ar mixed gas, the flow rate of the reducing gas is 50mL/min, and the temperature is increased to 900 ℃ at the heating rate of 10 ℃/min; detecting signal by Thermal Conductivity Detector (TCD) during the heating process to obtain TPR profile curve. The temperature corresponding to the peak value of the low-temperature reduction peak with the largest area in the TPR map curve is used as an index for evaluating the regenerability of the passivated catalyst, and the lower the temperature corresponding to the peak value of the low-temperature reduction peak with the largest area is, the easier the catalyst is regenerated.

According to the invention, the nickel content is preferably 45 to 70% by weight, calculated as oxide, based on the total amount of catalyst.

The present invention has a wide range of options for the support, and preferably the support of the hydrogenation catalyst is at least one selected from the group consisting of alumina, silica, zirconia and titania.

Preferably, the carrier is present in an amount of 30 to 55 wt.%, more preferably 32 to 50 wt.%, based on the total amount of catalyst.

According to a preferred embodiment of the invention, the catalyst further comprises an auxiliary agent, which is an element that contributes to the improvement of the catalyst performance. The auxiliary agent can be at least one of IIA element, IB element, IIB element, IVB element, lanthanide element, VIB element, VIIB element, VIII element and IVA element. More preferably, the auxiliary is selected from at least one of Zr, la, ce, W, mn, ti, si, al, cu, co, zn, ca and Mg.

Further preferably, the content of the auxiliary agent is 0.001 to 25% by weight, more preferably 0.01 to 10% by weight, in terms of oxide, based on the total amount of the catalyst.

In the present invention, the hydrogenation catalyst may be in the form of at least one of a cylinder, a gear, a raschig ring, and a sphere, for example, and may be used in the present invention. Preferably, the particle size of the hydrogenation catalyst is 3-10mm. The particle size refers to the maximum linear distance between any two different points on the catalyst particles; for example, when the catalyst is a spherical particle, the particle diameter refers to the diameter thereof.

The pre-reduced hydrogenation catalyst with high nickel content provided by the invention has high catalytic activity, proper reduction degree, good reactivation performance, multiple active centers and good stability.

Preferably, the nickel content is 45 to 70% by weight, calculated as oxide, based on the total amount of catalyst. The process provided by the invention is particularly suitable for catalysts having such a high nickel content.

In the preparation method, hydrogen is introduced into the stage 1) in the reduction process (the hydrogen has good heat conduction and diffusion properties and can improve the heat transfer and mass transfer efficiency), so that the catalyst can be subjected to preliminary reduction while being drained, and on one hand, the adverse effect of water vapor on reduction can be reduced; on the other hand, the strength of the high-nickel-content oxidation-state hydrogenation catalyst can be prevented from being reduced due to the fact that water is greatly discharged in a short time in the reduction process of the high-nickel-content oxidation-state hydrogenation catalyst. Nickel with proper grain size can be obtained by controlling the overall reduction time, so that more active center numbers can be obtained; and by matching with proper passivation conditions, the catalyst which is easy to regenerate and has a large number of active centers is obtained. The above aspects of the measures generally improve the performance of the resulting catalyst.

In the present invention, it is understood that a deactivation temperature of not higher than 80 ℃ means that the deactivation temperature of the hydrogenation catalyst bed is not higher than 80 ℃. Preferably, the passivation temperature is controlled to be not higher than 70 ℃.

Preferably, the carrier of the high nickel content oxidation state hydrogenation catalyst is selected from at least one of alumina, silica, zirconia and titania.

Preferably, the support is present in an amount of from 30 to 55% by weight, based on the total amount of high nickel content oxidation state hydrogenation catalyst.

Preferably, the high nickel content oxidation state hydrogenation catalyst also contains an auxiliary agent. The kind of the auxiliary agent is the same as the optional range of the auxiliary agent of the aforementioned first aspect. More preferably, the auxiliary is selected from at least one of Zr, la, ce, W, mn, ti, si, al, cu, co, zn, ca and Mg.

It is further preferred that the promoter is present in an amount of from 0.001 to 25% by weight, calculated as oxide, based on the total amount of high nickel content oxidation state hydrogenation catalyst.

Preferably, the high nickel content oxidation state hydrogenation catalyst has a particle size of from 3 to 10mm. The particle size is calculated in the same manner as described above and will not be described in detail here.

According to the invention, preferably, the reducing atmosphere contains hydrogen and optionally a protective gas. Protective gas generally refers to a gas that does not participate in the reduction reaction.

Preferably, the concentration of hydrogen in the reducing atmosphere is not lower than 5% by volume, more preferably 5 to 80% by volume, still more preferably 10 to 80% by volume, and may be, for example, 10, 12, 15, 20, 25, 30, 35, 40, 45, 55, 60, 65, 70, 75, 80% by volume, and a range between any of the point values.

Preferably, the protective gas is selected from at least one of nitrogen, helium, argon and neon, more preferably nitrogen.

In the present invention, preferably, the reducing atmosphere is provided by the following method: protective gas is introduced first, and then hydrogen is introduced. The ratio of the gas to the agent in this scheme is calculated as the reducing atmosphere (i.e., the mixture of hydrogen and a protective gas, also referred to as a hydrogen-containing gas).

According to one embodiment of the invention, the method further comprises: before the reduction, the protective gas is adopted to replace the gas in the reduction system, so that O in the reduction system is ensured ₂ The content of (2) is less than or equal to 0.5 volume percent, and then the pressure of a reduction system is kept to be 0-0.2MPa (gauge pressure); a reducing gas (i.e., hydrogen or a hydrogen-containing gas) is then introduced to meet the reducing atmosphere composition, and the reduction is performed in accordance with the reduction process. The preferable scheme can prevent the explosion after the excessive oxygen is mixed with the reducing gas, and ensure the safe operation of the device.

Further preferably, the method further comprises the step of heat exchanging: the introduced reducing gas (i.e., hydrogen or hydrogen-containing gas) or protective gas is first heat exchanged with the reduced gas and then heated. The reduced tail gas is subjected to heat exchange and temperature reduction and then is subjected to gas-liquid separation preferentially, and the tail gas after water removal can be recycled in the reduction process.

According to the present invention, preferably, the aerosol ratio of step (1) is 700 to 5000.

More preferably, the gas to agent ratio of stage 1) is from 1000 to 4000 and the gas to agent ratio of stage 2) is from 1500 to 4500. Under the preferred scheme, the reduction process of the catalyst is promoted, so that the catalyst is uniformly and moderately reduced.

According to a preferred embodiment of the invention, the reduction comprises: stage 1) raising the temperature to 170-280 ℃ at a heating rate of 70-120 ℃/hour, and preserving the temperature for 1-5 hours; stage 2) raising the temperature to 320-500 ℃ at a heating rate of 50-150 ℃/h, and preserving the temperature for 1-8 h.

According to another preferred embodiment of the invention, the reduction comprises: stage 1) raising the temperature to 180-270 ℃ at a heating rate of 70-120 ℃/hour, and preserving the temperature for 1-5 hours; stage 2) raising the temperature to 340-480 ℃ at a heating rate of 60-150 ℃/hour, and preserving the heat for 1-8 hours.

In a preferred embodiment of the invention, stage 2) of the reduction comprises: stage 2-1) raising the temperature to 320-400 ℃ at a heating rate of 50-150 ℃/hour, and preserving the temperature for 0.5-6 hours; stage 2-2) raising the temperature to 420-490 ℃ at a heating rate of 50-150 ℃/hour, and preserving the temperature for 0.3-4 hours. According to the invention, a two-stage heating reduction method is adopted in the reduction stage 2), so that on one hand, nickel oxide in the catalyst is fully reduced, the reduction degree of the hydrogenation catalyst is improved to a proper range, and by using hydrogen with higher concentration, heat conduction and diffusion are accelerated, and the adverse effect of water on reduction is reduced.

According to the present invention, it is preferable that the hydrogen concentration of the reducing atmosphere introduced in the stage 2-1) is not lower than that in the stage 2-2). Under the preferred scheme, the reduction process of the catalyst can be promoted, so that the catalyst is uniformly and moderately reduced.

According to a preferred embodiment of the invention, the reduction is carried out at a pressure of 0-0.2 MPa. The pressure is a gauge pressure.

According to the present invention, in step (2), it is preferable that the catalyst obtained by the reduction in step (1) is passivated by lowering the temperature of the catalyst obtained by the reduction in step (1) to 50 ℃.

In the present invention, the manner of cooling the catalyst obtained by the reduction in the step (1) is not limited at all, as long as the catalyst can be cooled to a desired temperature, for example, by heat exchange, cold exchange, water cooling, ammonia cooling, or the like.

In the present invention, preferably, the method further comprises: in step (2), after the catalyst obtained by the reduction in step (1) is cooled to 60 ℃ or lower (preferably to 50 ℃ or lower), the catalyst is purged with a protective gas, and then the passivation is performed.

According to the present invention, the passivation time is preferably 2 to 70 hours, more preferably 6 to 60 hours, still more preferably 10 to 40 hours. Whereas the passivation time in the prior art prereduction process is typically above 48 hours.

In step (2) of the present invention, the "continuously increasing oxygen concentration of the oxygen-containing gas" means that the oxygen concentration in the introduced oxygen-containing gas is generally in an increasing trend, for example, 1, the oxygen concentration in the introduced oxygen-containing gas may be continuously increasing (i.e., the oxygen concentration is increased at a certain speed); 2. the oxygen concentration in the introduced oxygen-containing gas may be increased after being stably introduced for a certain period of time, that is, the oxygen concentration may be increased in stages, for example, in a plurality of stages, in one embodiment, the oxygen concentration in the latter stage is higher than the oxygen concentration in the former stage, and in another embodiment, the oxygen concentration in the former stages is the same and lower than the oxygen concentration in the latter stage, so that the overall increase is made.

The oxygen concentration of the oxygen-containing gas is continuously increased in a wide optional range, and the oxygen concentration can be regularly and continuously increased, for example, the oxygen concentration is continuously increased by 2 times or exponentially increased; the oxygen concentration in the second stage and the oxygen concentration in the first stage may be increased irregularly, for example, the oxygen concentration in the third stage and the oxygen concentration in the second stage may be increased by 1-fold, the oxygen concentration in the fourth stage and the oxygen concentration in the third stage may be increased by 1.2-fold, and the oxygen concentration in the fourth stage and the oxygen concentration in the third stage may be increased by 2-fold.

In the present invention, preferably, the oxygen concentration of the oxygen-containing gas is continuously increased in stages, in which case, the duration of each stage is selected in a wider range, so long as the performance of the obtained catalyst is improved, more preferably, during the passivation process, when the oxygen-containing gas introduced in the previous stage makes the oxygen concentration in the passivated outlet gas equal to the oxygen concentration of the introduced oxygen-containing gas, the oxygen-containing gas is introduced in the latter stage.

According to the present invention, preferably, the oxygen concentration of the oxygen-containing gas is continuously increased during the passivation process in at least 3 stages. It will be appreciated that in this preferred embodiment, the oxygen concentration of the first stage oxygen-containing gas is lower than the oxygen concentration of the second stage oxygen-containing gas, which is lower than the oxygen concentration of the third stage oxygen-containing gas, and thus increases continuously. Further, it is understood that the relative multiples of the oxygen concentration of the oxygen-containing gas of each adjacent two stages may be the same or different independently, for example, the relative multiples of the oxygen concentration of the oxygen-containing gas of the first stage and the second stage may be 1.5, and the relative multiples of the oxygen concentration of the oxygen-containing gas of the second stage and the third stage may be 1.5, or 2.

Further preferably, during the passivation process, the oxygen concentration of the oxygen-containing gas is continuously increased in 3-12 stages, for example, the number of stages may be any point value of 4, 5, 6, 7, 8, 9, 10, 11, 12, and more preferably, the oxygen concentration is continuously increased in 4-9 stages. By adopting the preferable scheme of the invention, the catalyst can be passivated more uniformly, so that the catalyst has more reduction active centers after being subjected to reduction activation.

Preferably, the passivated gas to agent ratio is in the range of 200 to 5000, e.g. any of 300, 400, 500, 1000, 1200, 1500, 2000, 3000, 4000, 5000 and any point values and ranges therebetween, more preferably 500 to 3000.

According to the present invention, preferably, in the passivation process, the gas-to-gas ratio of the former stage is not lower than the gas-to-gas ratio of the latter stage. Under the preferred scheme, the uniform passivation process of the catalyst is promoted, and the passivation efficiency is improved.

In the present invention, the oxygen-containing gas is preferably a mixture of a protective gas and oxygen, and the protective gas is one or more selected from helium, argon, carbon dioxide and nitrogen.

In the invention, the method further comprises the following steps: before the passivation, protective gas (preferably 10-20:1 by volume of carbon dioxide and N ₂ ) Then, oxygen is introduced again so that the amount of oxygen in the passivation atmosphere satisfies the required oxygen concentration, and then the passivation is performed. The passivated gas is recycled or directly discharged.

According to the invention, when the reduction and passivation are carried out using the same apparatus, it is preferable to carry out the passivation after the reduction by introducing a protective gas to displace the hydrogen in the system.

Preferably, the passivation temperature is preferably not higher than 80 ℃ by adjusting the amount of protective gas (preferably carbon dioxide) pumped.

Preferably, the concentration of the oxygen-containing gas is 0.01 to 21% by volume.

According to a preferred embodiment of the present invention, the initial oxygen concentration of the introduced oxygen-containing gas during the passivation process is 0.01 to 1% by volume, more preferably 0.01 to 0.1% by volume, still more preferably 0.02 to 0.1% by volume. The adoption of the oxygen-containing gas with lower initial oxygen concentration can lead the passivation to be uniform and controllable, and is more beneficial to obtaining the catalyst which is easy to be reduced again.

According to the present invention, preferably, in the passivation process, the oxygen concentration of the oxygen-containing gas introduced in the latter stage is 1 to 3 times that of the oxygen-containing gas introduced in the former stage. Under the preferred scheme, the catalyst can be passivated more uniformly and controllably, so that the obtained catalyst has more reduction active centers after being subjected to re-reduction treatment, and the passivation efficiency is high.

In the present invention, preferably, in the passivation process, the concentration of the oxygen-containing gas introduced in the final stage is 21% by volume, that is, air is introduced.

In the invention, the reducing gas (namely the reducing atmosphere) and the passivation gas (namely the oxygen-containing gas) can be used in a disposable way, and can also be recycled by adopting recycle gas; preferably, the gas is recycled.

In the present invention, there is no limitation on the apparatus used for the reduction, and for example, the main apparatus for the reduction may be a reduction furnace or a reduction reactor, the reduction apparatus may be a rotary furnace, a moving bed reactor, a fixed bed reactor, the apparatus may be in the shape of a cylinder, a double cone, a sphere, etc., or an axial reactor or a radial reactor. A fixed bed reactor (e.g., an axial reactor in the form of a flat cylinder with an aspect ratio of 0.3 to 0.8) is preferred in order to reduce the residence of water vapor in the catalyst bed as much as possible, reduce the catalyst uniformly at different bed positions, and at the same time, not to impair the mechanical strength of the catalyst. The invention is not limited in any way to the equipment used for the passivation, for example, the main equipment for passivation may be a passivation furnace. The invention can also be matched with a heat exchanger, a cold exchanger, a water cooler, an ammonia cooler, a dryer, a regenerative heating furnace and a circulating fan. The reduction device and the passivation device may be configured separately or may share one, preferably the other, of the devices.

The source of the high-nickel-content oxidation state hydrogenation catalyst is not particularly limited, the catalyst can be obtained commercially or by self-making, the preparation method of the catalyst has a wide optional range, and the catalyst can be used in the invention as long as the catalyst can be prepared. In a preferred embodiment of the present invention, the high nickel content oxidation state hydrogenation catalyst is prepared by a co-precipitation process.

According to a preferred embodiment of the present invention, the co-precipitation method comprises: the water-soluble nickel source, the support precursor and optionally the water-soluble auxiliary agent are subjected to a coprecipitation reaction in the presence of a precipitant, and the resulting reaction mixture is aged, washed and optionally dried (preferably dried), followed by calcination and shaping.

The present invention is not limited in any way to the precipitant as long as the coprecipitation reaction can be performed; preferably, the precipitant is selected from at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, sodium metaaluminate, ammonia water and sodium hydroxide.

Preferably, the water-soluble nickel source is selected from at least one of nitrate, acetate and chloride of nickel, for example at least one of nickel nitrate, nickel chloride and nickel acetate.

Preferably, the water-soluble auxiliary is selected from nitrate, acetate or chloride containing auxiliary. The auxiliary agent is the same as the auxiliary agent. The water-soluble auxiliary is more preferably a nitrate of at least one of Zr, la, ce, W, mn, ti, si, al, cu, co, zn, ca and Mg.

Preferably, the carrier precursor is selected from at least one of silica sol, water glass, alumina sol, sodium metaaluminate, aluminum nitrate, zirconium nitrate, and tetrabutyl titanate. The concentration of silica in the silica sol can be freely selected by those skilled in the art, and the present invention is not limited thereto.

Preferably, the precipitant, the water-soluble nickel source, the carrier precursor and the water-soluble auxiliary agent are used in amounts such that the high nickel content oxidation state hydrogenation catalyst is prepared, wherein the nickel content is 40-75 wt%, the carrier content is 30-55 wt% and the auxiliary agent content is 0-25 wt% in terms of oxide.

In the present invention, the amount of the precipitant is not limited at all, as long as it enables the coprecipitation reaction to take place and an oxidation state hydrogenation catalyst of a desired composition to be produced, and one skilled in the art can select according to actual demands and a conventional amount range, for example, the amount of the precipitant is such that the pH of the solution of the coprecipitation reaction satisfies the demands.

Preferably, the conditions of the coprecipitation reaction include: the reaction temperature is 40-80 ℃, preferably the pH at the completion of the coprecipitation reaction is 7-9. In the present invention, pH refers to the pH of the solution at the completion of the coprecipitation reaction, for example, in the case of performing the complete precipitation reaction, the coprecipitation is stopped when ph=8.

The present invention is not limited in the order and manner of introduction of the water-soluble nickel source, carrier precursor and optional water-soluble auxiliary agent and precipitant, and can be freely selected by those skilled in the art. Preferably, the coprecipitation method further includes a step of mixing the respective raw materials. The invention is not limited to the manner of mixing the precipitant with the water-soluble nickel source, the carrier precursor and the optional water-soluble auxiliary agent, and for example, the precipitant may be added to a mixed salt solution containing the water-soluble nickel source, the carrier precursor and the optional water-soluble auxiliary agent, or a mixed salt solution containing the water-soluble nickel source, the carrier precursor and the optional water-soluble auxiliary agent may be added to the precipitant solution, or both may be added in parallel; the precipitant is preferably added to the mixed salt solution containing the water-soluble nickel source, the carrier precursor and optionally the water-soluble auxiliary agent. The precipitant is preferably introduced as an aqueous solution, preferably at a temperature of 30-70 ℃. More preferably, the mixed salt solution is configured by the following process: firstly, mixing optional water-soluble auxiliary agent (preferably in the form of aqueous solution) and water-soluble nickel source (preferably in the form of aqueous solution) (preferably heating to 40-80 ℃ under the stirring speed of 20-150 revolutions per minute) to obtain metal salt mixed solution; the metal salt mixed solution is then mixed with the carrier precursor (preferably in the form of an aqueous solution), preferably with stirring at a stirring speed of 20-150 revolutions per minute. The concentration of each of the above-mentioned respective aqueous solutions is not limited in any way as long as the respective solutes can be dissolved, and can be freely selected by those skilled in the art according to the need.

Preferably, the aging conditions include: the aging temperature is 30-70 ℃ and the aging time is 1-8 hours.

In the present invention, there is no limitation in the manner of the washing, and for example, the washing may be performed 2 to 6 times with deionized water.

Preferably, the conditions of the calcination include: the calcination temperature is 300-500 ℃, more preferably 350-450 ℃, and the calcination time is 2-10 hours.

According to a preferred embodiment of the present invention, the drying process includes: the precipitate obtained after the washing is dried at 80-180 ℃ for 2-24 hours.

According to another preferred embodiment of the present invention, the drying process includes: pulping the precipitate obtained after washing to obtain slurry with the solid content of 15-50 wt%, and spray drying the slurry.

In the present invention, the beating is preferably performed under stirring, and the stirring time is preferably 1 to 6 hours. It will be appreciated that the beating is carried out by introducing a solvent, preferably water, and the slurry is an aqueous slurry.

More preferably, the spray drying conditions include: the atomization pressure is 1-5MPa, the inlet temperature is 250-400 ℃, the outlet temperature is 80-160 ℃, and the atomization drying time is 2-5s. It will be appreciated that the spray drying is carried out in a spray dryer, the inlet and outlet temperatures being the inlet and outlet temperatures of the spray dryer, respectively.

In the invention, microsphere particles are obtained after the spray drying, and the microsphere particles are subjected to subsequent calcination and molding. The method of molding is not limited in any way, and any method commonly used in the art can be adopted, for example, tablet molding can be adopted. Preferably, the forming process includes: and mixing the calcined material with a lubricant and a forming agent, and tabletting and forming. The person skilled in the art can choose, according to the actual requirements, the lubricants, such as graphite, used in an amount of preferably 2-3% by weight of the product obtained after shaping, and the shaping agents, such as at least one of calcium aluminate cement, alumina and aluminum silicate, used in a total amount of preferably 5-10% by weight of the product obtained after shaping. The particle size of the catalyst after tabletting is preferably 3-8mm.

In the invention, the method further comprises the following steps: the high nickel content oxidation state hydrogenation catalyst is heated and then the reduction is performed. The heating may be by a preheated gas or may be heated in the reduction apparatus.

In a third aspect, the present invention provides a pre-reduced high nickel hydrogenation catalyst prepared by the preparation method described in the second aspect. The pre-reduced high nickel content hydrogenation catalyst has the composition of the pre-reduced high nickel content hydrogenation catalyst of the first aspect described above, and will not be described in detail herein.

According to the invention, preferably, the pre-reduced high nickel content hydrogenation catalyst has a degree of reduction of 50-90% as characterized by TPR. The pre-reduced hydrogenation catalyst with high nickel content provided by the invention has proper reduction degree and higher activity. The prior art pre-reduction catalyst has higher reduction degree (approaching 100 percent) and low activity.

In the invention, the method for testing the reduction degree comprises the following steps: testing the TPR map curve of the pre-reduction catalyst; and then roasting 0.2g of the pre-reduced catalyst for 2 hours at the temperature of 450 ℃ in an air atmosphere to obtain an oxidation state catalyst, testing the TPR profile of the oxidation state catalyst according to the TPR test method of the first aspect, and calculating the reduction degree of the pre-reduced catalyst. Wherein, the reduction degree= (oxidation state catalyst directly reduces TPR peak area-pre-reduction catalyst high temperature unreduced peak area)/oxidation state catalyst directly reduces TPR peak area by 100%.

The present invention will be described in detail by examples.

Example 1

(1) Preparation of high nickel content oxidation state hydrogenation catalyst

198kg of Ni (NO) ₃ ) ₂ ·6H ₂ O, 20kg of Al (NO) ₃ ) ₃ ·9H ₂ O is dissolved in 500L of deionized water to prepare mixed metal salt solution, and the mixed metal salt solution is kept at a constant temperature of 45 ℃. 85kg of silica sol GS-30 (silica concentration: 30% by weight) was added to 100L of water at a stirring speed of 50r/min, and stirred uniformly to obtain a silica sol solution. Mixing the mixed metal salt solution and the silica sol solution, stirring at the speed of 50r/min, and uniformly stirring to obtain the base solution of the catalyst.

110kg of Na ₂ CO ₃ Dissolving in 500L deionized water to prepare a precipitant solution, maintaining the precipitant solution at a constant temperature of 45 ℃, gradually dripping the precipitant solution into a base solution of a catalyst, continuously stirring to perform a complete precipitation reaction, taking pH=8 as a titration end point, aging for 2 hours at 45 ℃ after uniform stirring, and washing the precipitated precursor with deionized water for three times to obtain a filter cake.

Pulping the filter cake and water, stirring for 1.5 hours to obtain slurry with the solid content of 35 wt%, conveying the slurry to a spray dryer, wherein the atomization pressure of the spray dryer is 2.5MPa, the inlet temperature of the spray dryer is 330 ℃, the outlet temperature of the spray dryer is 130 ℃, and flowing out from the outlet of the spray dryer for 5 seconds to obtain microsphere particles. Calcining at 400 ℃ for 2 hours, mixing the calcined product and graphite (the graphite dosage is 2% by weight based on the total amount of the product obtained after molding) and calcium aluminate cement (the calcium aluminate dosage is 8% by weight based on the total amount of the product obtained after molding), uniformly mixing, and pressing into tablets with the particle size of 4 x 4mm to obtain the high nickel content oxidation state hydrogenation catalyst.

(2) Preparation of pre-reduced high nickel content hydrogenation catalyst

Placing the prepared high-nickel-content oxidation-state hydrogenation catalyst in a reactor, firstly introducing a nitrogen substitution system into the reactor until oxygen is qualified (the oxygen content is less than or equal to 0.5 vol%), then supplementing hydrogen to enable the hydrogen content in the hydrogen-nitrogen mixed gas to be 40 vol%, and then starting a multi-stage reduction process, wherein stage 1) introducing the mixed gas with the gas-to-catalyst ratio of 1000, and heating the catalyst to 200 ℃ at a heating rate of 80 ℃/hour, and keeping the temperature for 2 hours; stage 2) introducing the mixed gas with the gas-agent ratio of 2000, stage 2-1) raising the temperature of the catalyst to 400 ℃ at a heating rate of 70 ℃/h, and keeping the temperature for 3 hours; then stage 2-2) was entered, the temperature of the catalyst was raised to 450℃at a rate of 60℃per hour, and this temperature was maintained for 1 hour, ending the reduction step.

And then introducing nitrogen to replace hydrogen in the system, cooling the reduced catalyst to below 45 ℃, and introducing oxygen-containing gas which is below 45 ℃ and is prepared from air and nitrogen and has the oxygen concentration of 0.1-21% by volume under normal pressure. And sequentially introducing oxygen-containing gases with oxygen concentrations of 0.1 volume percent, 0.2 volume percent, 0.4 volume percent, 0.8 volume percent, 1.2 volume percent, 3.0 volume percent, 8.0 volume percent and 21 volume percent into 8 sections, wherein after the oxygen-containing gas in the previous stage is introduced, when the oxygen concentration at the gas outlet is equal to the oxygen concentration at the gas inlet, the oxygen-containing gas in the later stage is introduced, so that the oxygen concentration is gradually increased to perform passivation until the passivation is finished. The gas-agent ratio of the first two sections of passivation is 1000, and the gas-agent ratio of the last six sections of passivation is 500. The passivation temperature of the catalyst bed is controlled to be less than 65 ℃ and the total passivation time is 24 hours. A passivated hydrogenation catalyst (i.e., a pre-reduced high nickel content hydrogenation catalyst) is obtained.

Comparative example 1

The procedure of example 1 was followed, except that the high nickel content oxidation state hydrogenation catalyst of example 1 was reduced in one step instead of the three-stage reduction of example 1, followed by passivation (passivation process same as example 1), specifically, the one-step reduction process was: after introducing a hydrogen-nitrogen mixture gas (composition and temperature were the same as those in example 1, gas-catalyst ratio: 500), the temperature of the catalyst was first raised to 550℃at a temperature-raising rate of 70℃per hour, and the temperature was maintained for 10 hours, to effect reduction.

Comparative example 2

The procedure was followed as in example 1, except that the reduction process was varied, specifically, the high nickel content oxidation state hydrogenation catalyst of example 1 was subjected to the physical dehydration and reduction steps of example 1 in CN104667931B, followed by passivation according to the passivation procedure of example 1.

Example 2

Placing the high nickel content oxidation state hydrogenation catalyst prepared in the embodiment 1 in a reactor, firstly introducing a nitrogen substitution system into the reactor until oxygen is qualified (the oxygen content is less than or equal to 0.5 vol%), then introducing hydrogen into the reactor to make the hydrogen content in the hydrogen-nitrogen mixed gas 40 vol%, then starting the multi-stage reduction process of the catalyst, stage 1) introducing the mixed gas with the gas-to-catalyst ratio of 1000, raising the temperature of the catalyst to 200 ℃ at a heating rate of 80 ℃/hour, and keeping the temperature for 2 hours to remove physical water; stage 2) introducing the mixed gas with the gas-agent ratio of 2500, stage 2-1) raising the temperature of the catalyst to 400 ℃ at a heating rate of 70 ℃/h, and keeping the temperature for 3 hours; then stage 2-2) was entered, the temperature of the catalyst was raised to 450℃at a rate of 60℃per hour, and this temperature was maintained for 1 hour, ending the reduction step.

Then introducing the nitrogen to replace the hydrogen in the system until the hydrogen content is less than or equal to 1 volume percent, cooling the reduced catalyst to below 40 ℃, and introducing oxygen-containing gas with the oxygen concentration of 0.05-21 volume percent, which is prepared by air and nitrogen and is below 40 ℃ under normal pressure. And sequentially introducing oxygen-containing gases with oxygen concentrations of 0.05 volume percent, 0.1 volume percent, 0.2 volume percent, 0.4 volume percent, 0.8 volume percent, 1.2 volume percent, 3.0 volume percent, 8.0 volume percent and 21 volume percent into 9 sections, wherein after the oxygen-containing gases in the previous stage are introduced, when the oxygen concentration at the gas outlet is equal to the oxygen concentration at the gas inlet, the oxygen-containing gases in the later stage are introduced, and the oxygen concentration is gradually increased to perform passivation until the passivation is finished. The gas-agent ratio of the first two sections of passivation is 1000, and the gas-agent ratio of the last six sections of passivation is 500. The passivation temperature of the catalyst bed is controlled to be less than 60 ℃ and the total passivation time is 25 hours. A passivated hydrogenation catalyst (i.e., a pre-reduced high nickel content hydrogenation catalyst) is obtained.

Example 3

Placing the high nickel content oxidation state hydrogenation catalyst prepared in the embodiment 1 in a reactor, firstly introducing a nitrogen substitution system into the reactor until oxygen is qualified (the oxygen content is less than or equal to 0.5 vol%), then supplementing hydrogen to enable the hydrogen content in the hydrogen-nitrogen mixed gas to be 75 vol%, starting a multi-stage reduction process of the catalyst, 1) introducing the mixed gas with the gas-to-catalyst ratio of 3000, raising the temperature of the catalyst to 200 ℃ at a heating rate of 80 ℃/hour, and keeping the temperature for 4 hours to remove physical water; stage 2) introducing the mixed gas with the gas-agent ratio of 2800, stage 2-1) raising the temperature of the catalyst to 400 ℃ at a heating rate of 60 ℃/h, and keeping the temperature for 3 hours; then stage 2-2) was entered, the temperature of the catalyst was raised to 450℃at a temperature-raising rate of 50℃per hour, and this temperature was maintained for 1 hour, ending the reduction step.

Then introducing the nitrogen to replace the hydrogen in the system until the hydrogen content is less than or equal to 1 volume percent, cooling the reduced catalyst to below 30 ℃, and introducing oxygen-containing gas with the oxygen concentration of 0.05-21 volume percent, which is prepared by air and nitrogen and is below 30 ℃ under normal pressure. And sequentially introducing oxygen-containing gases with oxygen concentrations of 0.05 volume percent, 0.1 volume percent, 0.2 volume percent, 0.4 volume percent, 0.8 volume percent, 1.2 volume percent, 3.0 volume percent, 8.0 volume percent and 21 volume percent into 9 sections, wherein after the oxygen-containing gases in the previous stage are introduced, when the oxygen concentration at the gas outlet is equal to the oxygen concentration at the gas inlet, the oxygen-containing gases in the later stage are introduced, and the oxygen concentration is gradually increased to perform passivation until the passivation is finished. The gas-agent ratio of the first three sections of passivation is 2000, and the gas-agent ratio of the last six sections of passivation is 500. The passivation temperature of the catalyst bed is controlled to be less than 50 ℃ and the total passivation time is 18 hours. A passivated hydrogenation catalyst (i.e., a pre-reduced high nickel content hydrogenation catalyst) is obtained.

Example 4

Placing the high nickel content oxidation state hydrogenation catalyst prepared in the embodiment 1 in a reactor, firstly introducing a nitrogen substitution system into the reactor until oxygen is qualified (the oxygen content is less than or equal to 0.5 vol%), then supplementing hydrogen to enable the hydrogen content in the hydrogen-nitrogen mixed gas to be 75 vol%, starting a multi-stage reduction process of the catalyst, 1) introducing the mixed gas with the gas-to-catalyst ratio of 3000, raising the temperature of the catalyst to 200 ℃ at a heating rate of 80 ℃/hour, and keeping the temperature for 2 hours to remove physical water; stage 2) introducing the mixed gas with the gas-agent ratio of 3000, stage 2-1) raising the temperature of the catalyst to 400 ℃ at a heating rate of 60 ℃/h, and keeping the temperature for 3 hours; then stage 2-2) was entered, the temperature of the catalyst was raised to 480℃at a temperature-raising rate of 50℃per hour, and this temperature was maintained for 1 hour, ending the reduction step.

Then introducing the nitrogen to replace the hydrogen in the system until the hydrogen content is less than or equal to 1 volume percent, cooling the reduced catalyst to below 30 ℃, and introducing oxygen-containing gas with the oxygen concentration of 0.05-21 volume percent, which is prepared by air and nitrogen and is below 30 ℃ under normal pressure. And sequentially introducing oxygen-containing gases with oxygen concentrations of 0.05 volume percent, 0.1 volume percent, 0.2 volume percent, 0.4 volume percent, 0.8 volume percent, 1.2 volume percent, 3.0 volume percent, 8.0 volume percent and 21 volume percent into 9 sections, wherein after the oxygen-containing gases in the previous stage are introduced, when the oxygen concentration at the gas outlet is equal to the oxygen concentration at the gas inlet, the oxygen-containing gases in the later stage are introduced, and the oxygen concentration is gradually increased to perform passivation until the passivation is finished. The gas-agent ratio of the first three sections of passivation is 2000, and the gas-agent ratio of the last six sections of passivation is 500. The passivation temperature of the catalyst bed is controlled to be less than 50 ℃ and the total passivation time is 22 hours. A passivated hydrogenation catalyst (i.e., a pre-reduced high nickel content hydrogenation catalyst) is obtained.

Example 5

The procedure of example 4 was followed, except that stage 2) was different (i.e., stage 2) in that only one stage was employed, specifically, the temperature of the catalyst was raised to 450℃at a temperature-raising rate of 60℃per hour, and this temperature was maintained for 4 hours, and the reduction step was ended, except that the procedure was the same as in example 4.

Example 6

The procedure of example 1 was followed, except that the gas-to-gas ratios of stage 1) and stage 2) were varied during the reduction, and the specific parameters are set forth in Table 1.

Example 7

The procedure of example 1 was followed, except that the hydrogen concentration of the reducing atmosphere introduced in stage 2-1) was lower than in stage 2-2) during the reduction, specifically, the hydrogen content of the hydrogen-nitrogen mixture was 50% by volume by supplementing hydrogen in stage 2-2).

Example 8

The procedure of example 1 was followed, except that the reduction procedure of stage 2) was varied and the specific parameters are set forth in Table 1.

Example 9

The process of example 1 was performed with the difference that the stage of introducing the oxygen-containing gas during the passivation was different, specifically, the oxygen-containing gas having an oxygen concentration of 0.15 to 21% by volume was introduced, and the oxygen-containing gas having an oxygen concentration of 0.15% by volume, 0.3% by volume, 1.0% by volume, 6% by volume, 12% by volume, 21.0% by volume was sequentially introduced in 6 stages; the gas-agent ratio of the first 2 sections of passivation is 2000, the gas-agent ratio of the second 4 sections of passivation is 1000, and the total passivation time is 30 hours.

Example 10

The process of example 1 was followed, except that the gas-to-gas ratio in the previous stage was lower than that in the later stage during the passivation, specifically, the gas-to-gas ratio in the first two stages of passivation was 2000, the gas-to-gas ratio in the last six stages of passivation was 2500, and the total passivation time was 35 hours.

Example 11

The process of example 1 was carried out with the difference that the stepwise concentration of the introduced oxygen-containing gas was varied during the passivation, specifically, the oxygen concentration was 0.2 vol%, 1.0 vol%, 2.0 vol%, 2.4 vol%, 3.0 vol%, 10.0 vol%, 15.0 vol%, 21 vol% respectively, and the total passivation time was 38 hours were introduced in 8 steps.

Example 12

The procedure of example 1 was followed, except that the process parameters used in the preparation of the pre-reduced high nickel hydrogenation catalyst were varied, and the process parameters shown in Table 1 were specifically used.

Some of the process parameters for some of the examples above are listed in table 1.

TABLE 1

Note that: s represents an example.

Test case

The performance test is carried out on the prepared pre-reduced hydrogenation catalyst with high nickel content, and the performance test is specifically as follows:

1. the activity of the catalyst was evaluated.

A. The activity of the catalyst was evaluated by the content of the number of active sites after the catalyst was subjected to the re-reduction treatment.

The number of active centers was H on an Autochem2950 full-automatic high pressure chemisorber manufactured by Micromeritics Co., USA ₂ Programmed temperature rising strippingAttachment (H) ₂ -TPD) test, the test method is: weighing 0.2000g of 40-60 mesh sample, and firstly performing reduction activation under the following conditions: h with hydrogen content of 10 vol% ₂ Ar mixed gas, the flow rate of the mixed gas is 50mL/min, and the temperature is increased to 200 ℃ at the heating rate of 10 ℃ per minute for reduction for 2h. H in the reduced catalyst with 10% by volume of hydrogen ₂ Cooling in Ar mixed gas, switching to Ar gas for purging after the temperature is reduced to 55 ℃, enabling Ar flow to be 20mL/min until a base line is stable, and then carrying out H ₂ TPD experiments. H ₂ The experimental conditions and procedure for TPD were: the carrier gas is Ar, the carrier gas flow is 20mL/min, the heating rate is 10 ℃/min, the final temperature is 400 ℃, and the Thermal Conductivity Detector (TCD) detects signals to obtain a TPD curve.

B. The proportion of nickel with catalytic activity in the catalyst is represented by the area of the desorption peak of TPD, and the larger the area of the desorption peak of TPD is, the higher the proportion of nickel with catalytic activity in the catalyst is. The TPD desorption peak area is obtained by the TPD curve obtained by the test method.

2. The method is characterized by using TPR to represent the regenerability of the catalyst, and specifically adopts the temperature corresponding to the peak value of the low-temperature reduction peak with the largest area in the TPR map curve as an index for evaluating the regenerability of the passivated catalyst, wherein the lower the temperature corresponding to the peak value of the low-temperature reduction peak with the largest area is, the easier the catalyst is regenerated.

TPR (i.e., temperature programmed reduction) characterization was performed using an Autochem2950 fully automatic high pressure chemisorber manufactured by Micromeritics, inc. of America under the following test conditions: 0.20g of sample is dehydrated for 1 hour by heating the sample to 120 ℃ at a heating rate of 10 ℃/min under 50mL/min Ar air flow, and TPR experiment is carried out after the temperature is reduced to 50 ℃, wherein the experimental conditions and procedures of the TPR are as follows: the reducing gas is H with the hydrogen content of 10 volume percent ₂ Ar mixed gas, the flow rate of the reducing gas is 50mL/min, and the temperature is increased to 900 ℃ at the heating rate of 10 ℃/min; and detecting signals through a Thermal Conductivity Detector (TCD) in the heating process to obtain a TPR map curve.

3. The reduction of the catalyst is obtained by the degree of reduction.

The specific method is as follows: 0.2g of the pre-reduced catalyst was calcined in an air atmosphere at 450℃for 2 hours to obtain an oxidized catalyst. And then testing the TPR map curve of the calcined oxidation state catalyst according to the TPR test method, and calculating the reduction degree of the pre-reduction catalyst. Wherein, the reduction degree= (oxidation state catalyst directly reduces TPR peak area-pre-reduction catalyst high temperature unreduced peak area)/oxidation state catalyst directly reduces TPR peak area by 100%.

The results of the above tests are listed in Table 2.

TABLE 2

As can be seen from Table 2, the number of active centers of the pre-reduced high-nickel-content hydrogenation catalyst prepared by the method is superior to that of the comparative example, and the area of the desorption peak of TPD of the embodiment is obviously higher than that of the comparative example, which shows that the pre-reduced high-nickel-content hydrogenation catalyst obtained by the method contains higher proportion of nickel with catalytic activity.

In addition, the catalyst provided by the invention has proper reduction degree and higher activity, and the reduction degree of the comparative example is too high, but the activity is obviously lower. It can be seen from the combination of the temperature corresponding to the peak value of the low-temperature reduction peak with the largest area in the TPR curve that, although the temperature corresponding to the peak value of the low-temperature reduction peak with the largest area in some embodiments of the present invention is higher than that in the comparative example, the regeneration performance is slightly inferior, but the catalyst of the present invention has a high proportion of activity on the basis of having a suitable reduction degree, i.e., the activity is significantly superior.

Among them, it is apparent from comparative example 4 that the catalyst prepared by the preferred reduction process of the present invention has higher activity and is more easily regenerated. As is evident from the comparison of example 1 and examples 6-8, the catalysts prepared using the preferred embodiments of the present invention have higher activity, higher degree of reduction, and easier regeneration characteristics. As is apparent from the comparison of example 1 and examples 10 to 11, the catalyst obtained by adopting the scheme of the present invention in which the oxygen concentration of the preferable oxygen-containing gas is increased 1 to 3 times as a whole, or the scheme of the preferable gas-to-gas ratio has relatively better activity under the other conditions.

In a word, the reduction and passivation treatment process in the preparation of the catalyst is simple to operate, mild in condition, good in passivation effect and good in catalyst reproducibility. The surface layer of the catalyst treated by the method is oxidized to form a compact oxide film, which prevents air from deeply oxidizing the inside of the catalyst, is convenient for storage and transportation, and is easy to be H when in use ₂ The reduction can rapidly show higher catalytic activity, greatly shortens the start-up time and brings good economic benefit to enterprises.

Application example

In order to further evaluate the reaction performance of the pre-reduced high nickel content hydrogenation catalyst of the present invention, a fixed bed reactor was used, 10mL of 40-60 mesh catalyst and 20mL of 40-60 mesh quartz sand were uniformly mixed, and the mixture was packed in a 100mL fixed bed reactor having an inner diameter of 12mm, and the pre-reduced high nickel content hydrogenation catalysts obtained in the above examples and comparative examples were tested, respectively.

1400ppm of acetaldehyde and 5000ppm of hydrogen peroxide were added to an aqueous methanol solution having a methanol content of 85 wt% to obtain a mixture, which was used as a raw material to evaluate hydrogenation performance and stability of the catalyst. Firstly, carrying out reduction on a pre-reduction catalyst at 200 ℃ for 2 hours, wherein the reduction atmosphere is an atmosphere containing hydrogen and nitrogen with the hydrogen concentration of 70% by volume, and the gas-agent ratio is 1000; then at the temperature of 60 ℃, the pressure of 2.0MPa and the raw material liquid hourly space velocity of 8h ^-1 、V(H ₂ ) Catalyst performance was evaluated at a V (feed) of 500. And the same reduction conditions as in example 4 were compared with the catalyst reduced in the reactor. The results are shown in Table 3.

TABLE 3 Table 3

Note that: the 90% settling time of the conversion means the time during which the conversion is maintained at 90% without a decrease.

The results in Table 3 show that the pre-reduced high nickel content hydrogenation catalysts employing the present invention have good reactivity and stability relative to the comparative examples. And the pre-reduced high nickel content hydrogenation catalyst has equivalent performance to the catalyst obtained by in-reactor reduction.

As is evident from the comparison of examples 1 and examples 6-8 and example 11, the catalyst prepared by the preferred embodiment of the present invention has higher activity and overall better reaction performance and stability.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims

1. A pre-reduced high nickel content hydrogenation catalyst having a nickel content of 40 to 75 wt% as oxide based on the total amount of the catalyst, the catalyst having an active center number of 0.1 to 0.5mmol hydrogen per g of catalyst after a re-reduction treatment, the re-reduction treatment conditions comprising: the temperature is 200 ℃, the time is 2 hours, the reducing atmosphere is the atmosphere containing hydrogen and argon with the hydrogen concentration of 10 volume percent, and the gas-agent ratio is 15000; the preparation method of the pre-reduced hydrogenation catalyst with high nickel content comprises the following steps: (1) Reducing the high nickel content oxidation state hydrogenation catalyst in a reducing atmosphere; the reduction includes: stage 1) raising the temperature to 160-300 ℃ at a heating rate of 60-150 ℃/hour, and preserving the temperature for 0.5-8 hours; stage 2) raising the temperature to 320-520 ℃ at a heating rate of 50-150 ℃/hour, and preserving the temperature for 0.3-8 hours; (2) And (3) reducing the temperature of the catalyst obtained by the reduction in the step (1) to below 60 ℃, and passivating the catalyst obtained by the reduction in the step (1), wherein the passivation comprises the following steps: continuously introducing oxygen-containing gas below 60 ℃ and controlling the passivation temperature to be not higher than 80 ℃; wherein the oxygen concentration of the oxygen-containing gas is continuously increased.

2. The hydrogenation catalyst according to claim 1, wherein the number of active sites after the catalyst is subjected to the re-reduction treatment is 0.1 to 0.4mmol hydrogen per g catalyst.

3. The hydrogenation catalyst according to claim 1 or 2, wherein the peak value of the largest area low temperature reduction peak in the TPR curve of the catalyst, characterized by TPR, corresponds to a temperature of 130-280 ℃.

4. The hydrogenation catalyst according to claim 1 or 2, wherein the nickel content is 45-70 wt.% on oxide basis, based on the total amount of catalyst.

5. The hydrogenation catalyst according to claim 1 or 2, wherein the carrier of the hydrogenation catalyst is selected from at least one of alumina, silica, zirconia and titania.

6. The hydrogenation catalyst according to claim 1 or 2, wherein the carrier is present in an amount of 30-55 wt.%, based on the total amount of catalyst.

7. The hydrogenation catalyst according to claim 1 or 2, wherein the carrier is present in an amount of 32-50 wt.%, based on the total amount of catalyst.

8. The hydrogenation catalyst according to claim 1 or 2, wherein the catalyst further comprises an auxiliary agent selected from at least one of Zr, la, ce, W, mn, ti, si, al, cu, co, zn, ca and Mg.

9. The hydrogenation catalyst according to claim 8, wherein the auxiliary is contained in an amount of 0.001 to 25% by weight on an oxide basis based on the total amount of the catalyst.

10. The hydrogenation catalyst according to claim 9, wherein the promoter is present in an amount of 0.01 to 10% by weight, calculated as oxide, based on the total amount of catalyst.

11. The hydrogenation catalyst according to claim 1 or 2, wherein the particle size of the hydrogenation catalyst is 3-10mm.

12. A method for preparing a pre-reduced high nickel content hydrogenation catalyst, the method comprising:

13. The process according to claim 12, wherein the high nickel content oxidation state hydrogenation catalyst has a nickel content of 45 to 70 wt% on an oxide basis based on the total amount of the catalyst.

14. The process according to claim 12 or 13, wherein,

the carrier of the high nickel content oxidation state hydrogenation catalyst is at least one selected from alumina, silica, zirconia and titania.

15. The process according to claim 14, wherein,

the content of the carrier is 30-55 wt% based on the total amount of the high nickel content oxidation state hydrogenation catalyst.

16. The process according to claim 12 or 13, wherein,

the high nickel content oxidation state hydrogenation catalyst also contains an auxiliary agent, wherein the auxiliary agent is selected from at least one of Zr, la, ce, W, mn, ti, si, al, cu, co, zn, ca and Mg.

17. The method according to claim 16, wherein,

the content of the auxiliary agent is 0.001-25 wt% based on the total amount of the high nickel content oxidation state hydrogenation catalyst, calculated as oxide.

18. The process according to claim 12 or 13, wherein,

the particle size of the high nickel content oxidation state hydrogenation catalyst is 3-10mm.

19. The method of claim 12 or 13, wherein the reducing atmosphere comprises hydrogen and optionally a protective gas.

20. The production method according to claim 19, wherein the concentration of hydrogen in the reducing atmosphere is not less than 5% by volume.

21. The production method according to claim 20, wherein the concentration of hydrogen in the reducing atmosphere is 5 to 80% by volume.

22. The method of claim 19, wherein the protective gas is selected from at least one of nitrogen, helium, argon, and neon.

23. The production method according to claim 12 or 13, wherein the gas-to-agent ratio of step (1) is 700 to 5000.

24. The process of claim 23 wherein the gas to agent ratio of stage 1) is 1000 to 4000 and the gas to agent ratio of stage 2) is 1500 to 4500.

25. The production method according to claim 12 or 13, the reduction comprising: stage 1) raising the temperature to 170-280 ℃ at a heating rate of 70-120 ℃/hour, and preserving the temperature for 1-5 hours; stage 2) raising the temperature to 320-500 ℃ at a heating rate of 50-150 ℃/h, and preserving the temperature for 1-8 h.

26. The method of preparation of claim 25, wherein stage 2) of the reduction comprises: stage 2-1) raising the temperature to 320-400 ℃ at a heating rate of 50-150 ℃/hour, and preserving the temperature for 0.5-6 hours; stage 2-2) raising the temperature to 420-490 ℃ at a heating rate of 50-150 ℃/hour, and preserving the temperature for 0.3-4 hours.

27. The production method according to claim 26, wherein the hydrogen concentration of the reducing atmosphere introduced in the stage 2-1) is not lower than that in the stage 2-2).

28. The preparation method according to claim 12 or 13, wherein the passivation time is 2 to 70 hours.

29. The method of claim 28, wherein the passivation time is 6-60 hours.

30. The production method according to claim 12 or 13, wherein the oxygen concentration of the oxygen-containing gas is continuously increased during the passivation process in at least 3 stages.

31. The production method according to claim 30, wherein the oxygen concentration of the oxygen-containing gas is continuously increased during the passivation process in 3-12 stages.

32. The production method according to claim 31, wherein the oxygen concentration of the oxygen-containing gas is continuously increased during the passivation process in stages 4 to 9.

33. The method of claim 12 or 13, wherein the passivated gas to agent ratio is 200-5000.

34. The method of claim 33, wherein the passivated gas to agent ratio is 500-3000.

35. The production method according to claim 34, wherein a gas-to-gas ratio in a preceding stage is not lower than a gas-to-gas ratio in a subsequent stage in the passivation process.

36. The production method according to claim 12 or 13, wherein the concentration of the oxygen-containing gas is 0.01 to 21% by volume.

37. The method of claim 36, wherein the initial oxygen concentration of the introduced oxygen-containing gas during the passivation process is 0.01-1% by volume.

38. The method of claim 37, wherein the initial oxygen concentration of the introduced oxygen-containing gas during the passivation process is 0.01-0.1% by volume.

39. The production method according to claim 12 or 13, wherein the oxygen concentration of the oxygen-containing gas introduced in the latter stage is 1 to 3 times the oxygen concentration of the oxygen-containing gas introduced in the former stage in the passivation process.

40. The preparation method according to claim 12 or 13, wherein the high nickel content oxidation state hydrogenation catalyst is prepared by a coprecipitation method.

41. The process of claim 40, wherein the co-precipitation process comprises: the water-soluble nickel source, the carrier precursor and optionally the water-soluble auxiliary agent are subjected to a coprecipitation reaction in the presence of a precipitant, and the resulting reaction mixture is aged, washed and optionally dried, followed by calcination and shaping.

42. The process according to claim 41, wherein the precipitating agent is at least one selected from the group consisting of sodium carbonate, sodium bicarbonate, potassium carbonate, aqueous ammonia and sodium hydroxide.

43. The process of claim 41, wherein the water-soluble nickel source is selected from at least one of nitrate, acetate and chloride of nickel, the water-soluble promoter is selected from at least one of nitrate, acetate and chloride of a promoter, and the carrier precursor is selected from at least one of silica sol, water glass, alumina sol, sodium metaaluminate, aluminum nitrate, zirconium nitrate and tetrabutyl titanate.

44. The process of claim 41 wherein the water-soluble nickel source, support precursor and water-soluble promoter are used in amounts such that the resulting high nickel content oxidation state hydrogenation catalyst comprises, on an oxide basis, from 40 to 75 wt.% nickel, from 30 to 55 wt.% support and from 0 to 25 wt.% promoter.

45. The process of claim 41, wherein the conditions of the coprecipitation reaction include: the reaction temperature is 40-80 ℃;

and/or, the aging conditions include: the aging temperature is 30-70 ℃ and the aging time is 1-8 hours;

And/or, the conditions of the calcination include: the calcination temperature is 300-500 ℃ and the calcination time is 2-10 hours.

46. The method of claim 45, wherein the conditions of the coprecipitation reaction include: the pH at the completion of the coprecipitation reaction is 7-9.

47. The method of claim 41, wherein the drying comprises:

drying the precipitate obtained after washing at 80-180 ℃ for 2-24 hours;

or pulping the precipitate obtained after washing to obtain slurry with the solid content of 15-50 wt%, and spray drying the slurry.

48. The method of claim 47, wherein the spray drying conditions comprise: the atomization pressure is 1-5MPa, the inlet temperature is 250-400 ℃, the outlet temperature is 80-160 ℃, and the atomization drying time is 2-5s.

49. A pre-reduced high nickel hydrogenation catalyst prepared by the process of any one of claims 12-48.

50. Use of the pre-reduced high nickel content hydrogenation catalyst of any one of claims 1-11 and 49 in HPPO recycle methanol hydrogenation reactions.