CN117772243A

CN117772243A - Preparation method of phosphorus-containing copper-zinc catalyst

Info

Publication number: CN117772243A
Application number: CN202211133395.3A
Authority: CN
Inventors: 翁肖一; 李娟�; 徐学军; 王海涛
Original assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2022-09-18
Filing date: 2022-09-18
Publication date: 2024-03-29

Abstract

The invention discloses a preparation method of a phosphorus-containing copper-zinc catalyst, which comprises the following steps: (1) Adding deionized water and phosphate into a gel forming reaction tank, and continuously introducing CO ₂ The Zn, cu-containing solution and the sodium metaaluminate solution are subjected to parallel flow gelling reaction under stirring to obtain slurry; (2) Continuously ageing the slurry obtained in the step (1) for n times in three-stage decreasing pH value, adding 1/n Al-containing solution each time when the first-stage pH value ageing is finished, and carrying out solid-liquid separation on the materials obtained after ageing, wherein the solid is a solidThe phase is subjected to a first drying and tabletting forming process to obtain a formed product, and is washed, second dried and roasted to obtain the phosphorus-containing copper-zinc catalyst. The catalyst prepared by the method has larger pore volume and pore diameter, small copper particle diameter and gradient pore distribution, so that the active metal copper and the auxiliary zinc have good dispersion property, have good synergistic effect, and improve the activity, selectivity and thermal stability of the phosphorus-containing copper-zinc catalyst and the service life of the catalyst.

Description

Preparation method of phosphorus-containing copper-zinc catalyst

Technical Field

The invention relates to a preparation method of a phosphorus-containing copper-zinc catalyst, in particular to a preparation method of a copper-zinc catalyst with high activity, high selectivity and good heat resistance.

Background

At present, the medium-pressure and low-pressure gas phase method is widely adopted in the world to synthesize methanol, and the catalyst is basically mixed oxide of copper, zinc and aluminum. CuO, znO, al in catalyst for synthesizing methanol ₂ O ₃ The three components have different roles, cuO is the main active component, znO and Al ₂ O ₃ Is an auxiliary agent. The catalyst has different preparation methods, carrier properties, compositions and contents, the obtained copper has different dispersities and copper particle sizes, and meanwhile, the copper in the metal active center has different synergistic effects with the oxide carrier, so that the catalyst has great influence on the activity, methanol selectivity and stability of the copper-based catalyst. The higher the copper dispersity is, the more metal atoms are exposed on the surface, the agglomeration of active centers is not easy to be caused, and sintering is reduced, so that the high activity of the catalyst is maintained. When the particle diameter of the copper is small, a large number of open bit surfaces and edge defect sites exist on the copper particles, so that key reaction intermediates can be strongly combined, and the methanol yield is increased. The selectivity of methanol is optimal within the range of 7-10 nm of copper particle size. Meanwhile, the grain sizes of Cu and the carrier are controlled to be similar, so that the surface contact of Cu and the carrier is increased, and the interaction between Cu and the carrier is enhanced.

Al ₂ O ₃ Not only plays a framework role in the catalyst, but also can disperse active components in the catalyst, cu/ZnO/Al ₂ O ₃ The catalyst activity is closely related to the distribution and morphology of the surface components, which are closely connected with the specific surface area and pore distribution of the catalyst, and the interaction at the interface of the metal carrier directly affects the activity. The pore distribution in the catalyst plays a critical role in Cu-ZnO synergy and Cu dispersibility. How to increase the specific surface area and pore volume of the catalyst and optimize the pore distribution, thereby improving the dispersity of the active components of the catalyst, the synergistic effect of Cu-ZnO and reducing the particle size of Cu, so that the catalyst has excellent activity and also hasGood selectivity has become the focus of research on copper-based catalysts.

CN101502803a discloses a preparation method of catalyst for preparing 1, 4-butanediol by selective hydrogenation of dimethyl maleate, and on the basis of two-step method, auxiliaries Mn, mg, cr and other metals are added. CN1660490a discloses a preparation method of a catalyst for synthesizing methanol, and a small amount of surfactant OP is added in the process of coprecipitation method. CN101733109a is a copper-based catalyst for methanol synthesis, and an organic aid (one or more of ethylene glycol, diethylamine, glycerol, magnesium stearate, and activated carbon) is added during the precipitation process. The method is to add the reagent in the precipitation process to improve the dispersibility of CuO in the surface of the catalyst, but the addition of the auxiliary agent does not increase the specific surface area and the pore volume, does not optimize the pore distribution, and improves the dispersion of the main active component CuO in the catalyst to be limited.

CN103372440a discloses a preparation method of a catalyst for synthesizing methanol. The method comprises the steps of mixing copper, zinc metal salt solution, sodium metaaluminate solution and CO ₂ The gas is parallel flow and gel formed to prepare the catalyst for synthesizing the methanol. The method can increase the specific surface area of the catalyst, has high dispersity of the active phase and increases the number of active centers, but the precipitated material has poor cohesiveness and is not easy to be pressed into tablets for molding, and meanwhile, the copper particle diameter in the catalyst is larger.

CN201811114240.9 discloses a copper-zinc catalyst and a preparation method thereof, wherein the catalyst contains an organic phosphonic acid compound and/or a carboxylic acid polymer and an organic carboxylic acid. The copper-zinc catalyst is prepared by carrying out parallel flow gelling reaction on a mixed solution A and a sodium metaaluminate solution to obtain slurry I, and aging; and then, the mixed solution B and the sodium carbonate solution are added into the aged slurry I in parallel flow and drop manner for gelling reaction to obtain slurry II, and then the slurry II is aged, dried and molded to obtain the catalyst. CN107774263a discloses a preparation method of a synthetic methanol catalyst, sodium metaaluminate alkaline solution and soluble salt solution containing Cu are simultaneously and concurrently added into a reaction tank filled with purified water to carry out a gelling reaction to generate slurry I, then sodium metaaluminate alkaline solution is dripped into the soluble salt solution containing Zn to carry out a gelling reaction to generate slurry II, the slurry I and the slurry II are uniformly mixed, aged and filtered, the obtained material is subjected to hydrothermal treatment by using water vapor, urea is added during the hydrothermal treatment, and then the catalyst is obtained through washing, filtering, drying, roasting and tabletting. The active metal copper content in the catalyst surface phase prepared by the method is high, but the dispersity of copper and zinc in the catalyst surface phase is reduced under the action of water vapor pressure and the impact of water molecules, and the particle size of copper is larger.

CN202011292868.5 discloses a preparation method of a high-activity high-selectivity synthetic methanol catalyst, in the method, a method of combining a two-step precipitation method with multi-step impregnation is adopted, and after the two-step precipitation, the precipitate is soaked in zinc nitrate solution, so that more active sites are formed; the impregnated magnesium can neutralize the surface acidity of the catalyst, thereby improving the selectivity of the catalyst. However, the catalyst Cu prepared by the method has larger particle size, and influences the selectivity of the catalyst.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method of a phosphorus-containing copper-zinc catalyst. The catalyst prepared by the method has larger pore volume and pore diameter, small copper particle diameter and gradient pore distribution, so that the active metal copper and the auxiliary zinc have good dispersion property, have good synergistic effect, and improve the activity, selectivity and thermal stability of the phosphorus-containing copper-zinc catalyst and the service life of the catalyst.

The preparation method of the phosphorus-containing copper-zinc catalyst comprises the following steps: (1) Adding deionized water and phosphate into a gel forming reaction tank, and continuously introducing CO ₂ The Zn, cu-containing solution and the sodium metaaluminate solution are subjected to parallel flow gelling reaction under stirring to obtain slurry; (2) Continuously ageing the slurry obtained in the step (1) for n times in three-stage decreasing pH values, adding 1/n of Al-containing solution each time when the first-stage pH value ageing is finished, carrying out solid-liquid separation on the materials obtained after ageing, carrying out a first drying and tabletting forming process on the solid phase to obtain a formed product, washing, second drying and roasting to obtain a phosphorus-containing copper-zinc catalyst;

Wherein, the second drying process is as follows: a. firstly, drying the material at 60-100 ℃ for 1.0-8.5 hours, preferably at 70-90 ℃ for 2.0-8.0 hours; b. uniformly spraying water (preferably deionized water) on the material obtained in the step a, wherein the volume ratio of water to dry material is 1:4~4:1, then drying at a temperature of 150-280 ℃, preferably 150-250 ℃ for 0.5-4.0 hours, preferably 0.6-3.5 hours; c. and (3) repeating the step b for 2-9 times, preferably 3-8 times.

In the method of the invention, in the Zn and Cu-containing solution in the step (1), the concentration of the soluble copper salt is Cu ²⁺ The concentration of the soluble zinc salt is calculated as Zn and is 0.4 to 3.5mol/L, preferably 0.5 to 3.0mol/L ²⁺ The content is 0.2 to 3.0mol/L, preferably 0.3 to 2.5mol/L. The soluble copper salt is nitrate and/or acetate containing copper, and the soluble zinc salt is nitrate and/or acetate containing zinc.

In the method of the invention, the concentration of the sodium metaaluminate solution in the step (1) is equal to Al ₂ O ₃ And is 10 to 90g/L, preferably 15 to 85g/L.

In the method of the invention, the phosphate ester in the step (1) is one or more of octadecyl ether phosphate ester (O-5P), alkylphenol ether phosphate ester (TXP-4, TXP-10), isomerism tridecyl ether phosphate ester (E-1310P), lauryl ether phosphate ester (MOA-3P, MOA-9P), castor oil phosphate ester, octadecyl phosphate ester and lauryl phosphate ester, preferably one or more of alkylphenol ether phosphate ester (TXP-4, TXP-10), isomerism tridecyl ether phosphate ester (E-1310P), lauryl ether phosphate ester (MOA-3P, MOA-9P) and castor oil phosphate ester. The molar ratio of the phosphate to the Al in the sodium metaaluminate solution in the step (1) is 0.2: 1-2.0: 1, preferably 0.3: 1-1.8: 1.

In the process of the present invention, CO is added as described in step (1) ₂ The gas concentration is 40-70 v%; CO ₂ The flow rate of the gas is 30-120 mL/min.

In the method of the invention, the gelling reaction conditions in the step (1) are as follows: the reaction temperature is 30-90 ℃, preferably 40-85 ℃, the pH value is initially controlled to be 10.0-14.0, preferably 10.5-13.5, the final pH value is 7.0-8.5, preferably 7.2-8.3 at the end, and the gel forming reaction time is 0.5-6.0 hours, preferably 0.6-5.0 hours.

Preferably, the pH value can be adjusted from the initial value to the final pH value by adopting a method of gradually adjusting the pH value to the required value, and the pH value of the reaction slurry is kept constant until the next adjustment, wherein the adjustment is carried out for 2-10 times, preferably 2-8 times.

Further preferably, the time period is constant for 0.1 to 1.2 hours after each down-regulation. The amplitude of each down-regulation may be the same or different, and preferably, the amplitude of each down-regulation pH decrease is equal to or smaller than the amplitude of the last down-regulation pH decrease. The time taken for each down-regulation process is the sum of the time taken for each down-regulation and the constant time at the pH value, and is further the sum of the time taken for each down-regulation and the constant time at the pH value. The time used for each down-regulation process may be the same or different, preferably the same.

In the method of the invention, in the step (2), the alkali used for adjusting the pH value can be inorganic salt, inorganic acid and inorganic alkali which do not contain aluminum elements, and further can be one or more of hydrochloric acid, acetic acid, sodium carbonate and sodium bicarbonate, and the concentration and the dosage of the acid and the alkali solution can be adjusted according to the actual preparation requirement.

In the method of the invention, in the step (2), the added Al accounts for the total Al in the obtained synthetic methanol catalyst and is Al ₂ O ₃ 5 to 45 percent, preferably 6 to 40 percent. When preparing the Al-containing solution, the common aluminum source is soluble aluminum salt, which can be one or more of aluminum nitrate, aluminum sulfate, aluminum chloride and the like, and is divided into n parts by volume, wherein n is an integer of 2-8.

In the method of the invention, the three-stage decreasing pH value aging process in the step (2) is specifically as follows: the aging temperature is 60-98 ℃, preferably 65-92 ℃; the first stage, wherein the pH value is 11.0-13.5, aging is carried out for 0.05-0.5 hours, and 1/n of Al-containing solution is added after the first stage aging is finished; second, adjusting the pH value to 8.5-10.5, and aging for 0.05-0.5 hours; thirdly, adjusting the pH to 5.5-8.3, and aging for 0.05-0.5 hours; wherein n is an integer of 2 to 8.

In the method of the invention, the solid-liquid separation in the step (2) generally adopts modes such as filtration, centrifugation and the like.

In the method, in the forming process in the step (2), a conventional forming extrusion aid can be added according to the requirement, wherein the extrusion aid is one or more substances beneficial to extrusion forming, such as carbon black, graphite powder and the like, and the consumption of the extrusion aid accounts for 1-10 wt% of the total material dry basis. The synthesized phosphorus-containing copper-zinc catalyst is in a cylindrical (solid) particle shape, and the particle size of the catalyst particle is 2-12 mm. The length can be 1-8 mm.

In the method of the present invention, the washing, the first drying and the calcination in the step (2) may be performed under the conditions conventional in the art, and the washing is performed with deionized water to be neutral. The first drying condition: drying at 50-150 ℃, preferably 60-120 ℃ for 0.5-24.0 hours, preferably 1-16 hours. The roasting conditions are as follows: roasting at 300-360 ℃ for 1-16 hours, preferably 2-10 hours.

In the method of the invention, in the second drying process in the step (2), the volume ratio of the first water adding volume to the dried material is greater than 1:1, the volume ratio of the last water adding volume to the dry material is less than 1:1, further, the volume ratio of the added water to the dried material is sequentially reduced along with the increase of the drying times.

The phosphorus-containing copper-zinc catalyst prepared by the method of the invention comprises the following components by taking the weight of the catalyst as a reference: 20 to 65 percent of CuO, 25 to 60 percent of preferential, 10 to 35 percent of ZnO, 12 to 32 percent of preferential and Al ₂ O ₃ 8 to 35 percent, preferably 12 to 32 percent, P ₂ O ₅ Calculated as 2% -16%, preferably 3% -14%.

The specific surface area of the metallic copper in the reduced catalyst is 45-140 m ² Preferably 50 to 130m ² And/g. The dispersity of the metallic copper is 20-50%, preferably 25-45%.

The average grain diameter of metallic copper in the phosphorus-containing copper-zinc catalyst prepared by the method is 7-10 nm; the particle size distribution of the metallic copper particles is as follows: the particle number of the particles with the particle size of less than 7nm accounts for 5% -17% of the total particle number, the particle number of the particles with the particle size of 7 nm-10 nm accounts for 62% -85% of the total particle number, and the particle number of the particles with the particle size of more than 10nm accounts for 5% -15% of the total particle number.

The phosphorus-containing copper-zinc catalyst prepared by the method of the invention is in the form of (solid) particles, preferably, the average pore diameter is from large to small from the outer surface layer of the catalyst to the central core. Preferably, the catalyst particles comprise an outer surface layer, an intermediate layer and a central core, the average pore diameter decreasing in a gradient, i.e. the average pore diameter of the outer surface layer is larger than the average pore diameter of the intermediate layer, which is larger than the average pore diameter of the central core. The average pore diameter of the outer surface layer is 12-18 nm, the average pore diameter of the middle layer is 8-12 nm, the average pore diameter of the central core is 4-8 nm, and the length from the outermost edge to the central point is R on the cross section of the catalyst particle. The thickness of the outer surface layer is 0.2R-0.4R, the thickness of the middle layer is 0.2R-0.5R, and the rest is the central core.

The phosphorus-containing copper-zinc catalyst prepared by the method is applied to the reaction of synthesizing methanol, and the general process conditions are as follows: the reaction temperature is 210-320 ℃, preferably 230-290 ℃; the pressure is 2.0-10 MPa, preferably 2.0-8.0 MPa; volume space velocity is 2000-15000 h ^-1 Preferably 4000 to 12000h ^-1 。

Compared with the prior art, the catalyst prepared by the method has the characteristics of more dispersed active metal, small particle size of metal copper particles, good synergistic effect between Cu and ZnO, high activity, high selectivity and heat resistance.

1. In the method, when the composite oxide of copper, zinc and aluminum is formed, the method of decreasing the pH value to form gel is adopted, so that the dispersity of metallic copper can be effectively improved, and good synergistic effect is generated between Cu and ZnO.

2. The method for preparing the phosphorus-containing copper-zinc catalyst of the invention adds the solution containing Al in the process of pH value swing during aging, thereby further improving the Al ₂ O ₃ The skeleton supporting function makes the pore canal smooth, facilitates the smooth passage of macromolecular reactant, promotes the dispersion of active metal, strengthens the promotion effect of the active metal, and facilitates the improvement of catalyst activity, methanol selectivity and thermal stability.

3. The invention prepares the copper zinc catalyst containing phosphorusMethod for converting agent and introducing CO ₂ When in gas, the concentration and the flow rate of the gas are controlled to obtain ideal reaction liquid microbubbles, and the generated microbubbles are suspended in water to be dissociated due to small volume of the microbubbles and continuously collide irregularly. The phosphate is a good surfactant, and under the combined action of the phosphate and the reaction solution microbubbles, the particle size of the metal copper particles in the catalyst is small, so that the dispersibility of the active metal is improved, the probability of micropores is reduced, the pore volume and the specific surface area of the bulk phase catalyst are increased, the diffusion efficiency of the catalytic process can be improved due to the proper pore diameter, more active sites are exposed by the catalyst, the utilization rate of the active metal is improved, and the catalytic activity is better exerted. Meanwhile, the addition of the auxiliary agent phosphorus effectively prevents the agglomeration of copper ions, so that copper and zinc oxide have better synergistic effect.

4. In the method, the second drying after forming adopts a drying method, so that the average pore diameter is from large to small from the outer surface layer to the central core of the catalyst in the pore distribution of the catalyst particles, thereby weakening the influence of diffusion effect when reactants enter and exit a catalyst pore canal, being beneficial to improving the selectivity and heat resistance of the catalyst, and further improving the interaction between Cu and ZnO.

Detailed Description

The following examples further illustrate the aspects and effects of the present invention. In the invention, the specific surface area, pore volume and pore distribution are measured by adopting a low-temperature liquid nitrogen adsorption method, and the specific surface area (S _Cu ) And dispersity (D) _Cu ) Using N ₂ O chemisorption method. v% is the volume fraction and wt% is the mass fraction.

In the present invention, the average particle diameter and particle diameter distribution of metallic copper are obtained by measuring 50 to 120 metallic copper particles by using a TEM transmission electron microscope (JSM-2100, japan).

In the present invention, the "cross section of the catalyst particle" refers to the entire surface exposed after cutting through the geometric center of the shape thereof along the direction of the smallest dimension of one catalyst particle. For example, when the catalyst particles are spherical, the cross section refers to the entire surface exposed after cutting through the center of the sphere along the radius or short axis of the sphere. Alternatively, when the catalyst particles are columnar, the cross section refers to the entire surface exposed after cutting through the center point of the length dimension perpendicular to the length dimension direction of the column. The outer perimeter of the exposed surface is referred to as the outermost edge of the cross-section, and the geometric center (such as the center point of the aforementioned sphere center or length dimension) is referred to as the center point on the cross-section.

In the invention, the method for measuring the average pore diameter of the outer surface layer to the central core of the catalyst particle comprises the following steps: the pore volume, specific surface area and average pore diameter of the sample were measured by a low temperature nitrogen adsorption method (BET), and then a certain amount of the sample was taken and placed in a catalyst abrasion meter, and the sample was subjected to polishing treatment while adding a certain amount of quartz sand to increase the abrasion rate. When the sample is reduced to a certain degree by polishing particle size, the weight loss of the sample is measured, the pore structure is measured again, the pore volume and the specific surface area of the polished part can be calculated according to the relation that the total pore volume and the specific surface area of the sample are equal to the sum of all the parts, 20-80 samples are measured at the same time, and the average pore diameter is calculated. The average pore diameter of the different layers from the outer surface layer to the central core was thus determined.

Example 1

334 g of Cu (NO) ₃ ) ₂ ·3H ₂ O and 164 g Zn (NO) ₃ ) ₂ ·6H ₂ O is dissolved in deionized water to prepare Zn and Cu containing solution. AlCl is added ₃ ·6H ₂ O is dissolved in deionized water to prepare aluminum chloride solution, and Al in the aluminum chloride solution accounts for the total Al in the obtained phosphorus-containing copper-zinc catalyst and is Al ₂ O ₃ 30% by volume and aliquoted into 5 parts by volume. Adding deionized water and castor oil phosphate with the mole ratio of 1.0 to the total Al atoms in sodium metaaluminate into a reaction tank, and introducing CO with the concentration of 50% by volume into the reaction tank solution ₂ Gas, CO ₂ The flow rate of the gas was 60ml/min. Sodium metaaluminate solution (containing Al ₂ O ₃ 21 g/L) and Zn and Cu-containing solution are added into a reaction tank in parallel, the gel forming temperature is 60 ℃, the pH value is initially controlled to be 13.1, and the final pH value at the end is adjusted to be 7.5 by reducing the pH value for 7 times, and each time the final pH value is reducedThe pH value of the reaction slurry is regulated to be 0.8, the pH value is controlled to be constant for 8 minutes after the reaction slurry is regulated every time to be regulated to be the regulating value, the slurry containing copper, zinc, aluminum and phosphorus is obtained after the reaction is finished, the obtained slurry is aged, the aging temperature is 76 ℃, the pH value is controlled to be 13.2 at first when the slurry is aged, the aging time is 0.2 hour, 1 part of aluminum chloride solution is added, the aging pH value is controlled to be 9.5 after the aging time is 0.15 hour, the pH value is controlled to be 7.6 again after the aging time is 0.15 hour, the operation process is repeated for 5 times, and the aging is finished. Filtering the aged slurry, drying the filter cake at 90 ℃ for 10 hours, adding a proper amount of graphite and water for rolling, and tabletting and forming. Washing the molding material with deionized water to neutrality, and drying the washed molding material for the second time as follows: firstly, drying the material at 70 ℃ for 5.0 hours, uniformly spraying deionized water on the dried material, then drying, and repeating the processes of uniformly spraying the deionized water and drying for 6 times, wherein the volume ratio of the first sprayed deionized water to the dried material is 1.5:1, drying temperature 180 ℃ and drying time 2.0 hours, wherein the volume ratio of the second spraying deionized water to the dried materials is 1.2:1, the drying temperature is 200 ℃, the drying time is 2.5 hours, and the volume ratio of the third spraying deionized water to the dried materials is 1:1, drying temperature 180 ℃ and drying time 2.0 hours, wherein the volume ratio of the fourth spraying deionized water to the dried materials is 1:1.2, the drying temperature is 150 ℃, and when the drying time is 1.7, the volume ratio of the deionized water sprayed for the fifth time to the dried materials is 1:1.8, drying temperature 170 ℃ and drying time 2 hours, wherein the volume ratio of the sprayed deionized water to the dried material for the sixth time is 1:2.5, drying temperature 170 ℃ and drying time 2 hours. The dried molded product was calcined at 360℃for 3 hours to obtain catalyst A. The composition, pore distribution and main properties are shown in Table 1.

Example 2

Cu (NO) was added in the same amount as the catalyst B in Table 1 according to the method of example 1 ₃ ) ₂ ·3H ₂ O、Zn(NO ₃ ) ₂ ·6H ₂ O is dissolved in deionized water to prepare Zn and Cu-containing solution, aluminum sulfate is dissolved in deionized water to prepare aluminum sulfate solution, and Al in the aluminum sulfate solution occupies the obtained synthesized phosphorus-containing solutionTotal Al in Cu-Zn catalyst is Al ₂ O ₃ 26% by volume and aliquoted into 6 parts by volume. Adding deionized water and alkylphenol ether phosphate (TXP-4) with the mole ratio of 0.8 to the total Al atoms in sodium metaaluminate into a reaction tank, and introducing CO with the concentration of 45v% into the reaction tank solution ₂ Gas, CO ₂ The flow rate of the gas was 80ml/min. And (3) adding the sodium metaaluminate solution and the Zn and Cu-containing solution into a reaction tank in parallel, wherein the gelling temperature is 55 ℃, the pH value is initially controlled to be 12.6, the final pH value at the end is adjusted to be 7.8 through 6 times of downward pH value adjustment, the pH value of each downward pH value adjustment is 0.8, the pH value of the reaction slurry after each downward pH value adjustment is constant for 10 minutes after each downward pH value adjustment, the slurry containing copper, zinc, aluminum and phosphorus is obtained, the obtained slurry is aged, the aging temperature is 80 ℃, the pH value is firstly controlled to be 12.9 during aging, the aging time is 0.2 hour, the aging pH value is controlled to be 9.0 after 1 equal part of aluminum sulfate solution is added, the aging time is 0.3 hour, the pH value is controlled to be 6.6, the aging time is 0.2 hour, the operation process is repeated for 6 times, and the aging is finished. Filtering the aged slurry, drying a filter cake at 90 ℃ for 8 hours, adding a proper amount of graphite and water for rolling, tabletting and forming, washing the formed product with deionized water to be neutral, and performing secondary drying on the washed formed product by the following steps: firstly, drying the material at 80 ℃ for 6.5 hours, uniformly spraying deionized water on the dried material, then drying, and repeating the processes of uniformly spraying the deionized water and drying for 6 times, wherein the volume ratio of the first sprayed deionized water to the dried material is 2:1, the drying temperature is 200 ℃, the drying time is 2.0 hours, and the volume ratio of the second spraying deionized water to the dried materials is 1.5:1, the drying temperature is 220 ℃, the drying time is 2.1 hours, and the volume ratio of the third spraying deionized water to the dried materials is 1:1, drying temperature 180 ℃ and drying time 2.0 hours, wherein the volume ratio of the fourth spraying deionized water to the dried materials is 1:1.5, drying temperature 180 ℃ and drying time 1.8 hours, wherein the volume ratio of the fifth spraying deionized water to the dried materials is 1:2.0, drying temperature 180 ℃ and drying time 1.9 hours, wherein the volume ratio of the sixth spray deionized water to the dried materials is 1:2.5, drying temperature 200 ℃ and drying time 1.5 hours. The dried molded product is at 350 DEG C Roasting for 4 hours to obtain the catalyst B. The composition, pore distribution and main properties are shown in Table 1.

Example 3

Cu (NO) was added in the same amount as that of catalyst C in Table 1 according to the method of example 1 ₃ ) ₂ ·3H ₂ O、Zn(NO ₃ ) ₂ ·6H ₂ O is dissolved in deionized water to prepare Zn and Cu-containing solution, alCl is added ₃ ·6H ₂ O is dissolved in deionized water to prepare aluminum chloride solution, and Al in the aluminum chloride solution accounts for the total Al in the obtained synthesized phosphorus-containing copper-zinc catalyst ₂ O ₃ 24% by volume and aliquoted into 5 parts by volume. Adding deionized water and laureth phosphate (MOA-9P) with a molar ratio of 0.7 to the total Al atoms in sodium metaaluminate into a reaction tank, and introducing CO with a concentration of 50v% into the reaction tank solution ₂ Gas, CO ₂ The flow rate of the gas was 80ml/min. And (3) adding the sodium metaaluminate solution and the Zn and Cu-containing solution into a reaction tank in parallel, wherein the gelling temperature is 65 ℃, the pH value is initially controlled to be 13.3, the final pH value at the end is adjusted to be 7.3 through 6 times of downward pH value adjustment, the pH value of each downward pH value adjustment is 1.0, the pH value of the reaction slurry after each downward pH value adjustment is constant for 12 minutes after each downward pH value adjustment is adjusted, the slurry containing copper, zinc, aluminum and phosphorus is obtained, the obtained slurry is aged, the aging temperature is 78 ℃, the pH value is firstly controlled to be 12.3 during aging, the aging time is 0.2 hour, the aging pH value is controlled to be 9.9 after 1 part of aluminum chloride solution is added, the aging time is 0.1 hour, the pH value is controlled to be 7.2, the aging time is 0.1 hour, the operation process is repeated for 5 times, and the aging is finished. Filtering the aged slurry, drying the filter cake at 100 ℃ for 7 hours, adding a proper amount of graphite and water for rolling, tabletting for molding, washing the molded product with deionized water to be neutral, and then performing secondary drying on the washed molded product by the following steps: firstly, drying the material at 72 ℃ for 6.0 hours, uniformly spraying deionized water on the dried material, then drying, and repeating the processes of uniformly spraying the deionized water and drying for 5 times, wherein the volume ratio of the first sprayed deionized water to the dried material is 1.5:1, drying temperature 180 ℃ and drying time 2.0 hours, spraying deionized water for the second time and drying material volume ratio Is 1:1, the drying temperature is 200 ℃, the drying time is 2.0 hours, and the volume ratio of the third spraying deionized water to the dried materials is 1:1.4, drying temperature is 180 ℃, drying time is 2.0 hours, and the volume ratio of the fourth spraying deionized water to the dried materials is 1:1.8, drying temperature 180 ℃ and drying time 1.6 hours, wherein the volume ratio of the fifth spraying deionized water to the dried materials is 1:2.3, drying temperature 170 ℃ and drying time 2 hours. The dried molded product was calcined at 340℃for 4 hours to obtain catalyst C. The composition, pore distribution and main properties are shown in Table 1.

Example 4

Cu (NO) was added in the same amount as that of catalyst D in Table 1 according to the method of example 1 ₃ ) ₂ ·3H ₂ O、Zn(NO ₃ ) ₂ ·6H ₂ O is dissolved in deionized water to prepare Zn and Cu-containing solution, alCl is added ₃ ·6H ₂ O is dissolved in deionized water to prepare aluminum chloride solution, and Al in the aluminum chloride solution accounts for the total Al in the obtained synthesized phosphorus-containing copper-zinc catalyst ₂ O ₃ 32% by volume and aliquoted into 6 parts by volume. Adding deionized water and isomeric tridecanol ether phosphate (E-1310P) with a mole ratio of 1.1 to the total Al atoms in sodium metaaluminate into a reaction tank, and introducing CO with a concentration of 55v% into the reaction tank solution ₂ Gas, CO ₂ The flow rate of the gas was 90ml/min. And (3) adding the sodium metaaluminate solution and the Zn and Cu-containing solution into a reaction tank in parallel, wherein the gelling temperature is 70 ℃, the pH value is initially controlled to be 12.2, the final pH value at the end is adjusted to be 7.7 through 5 times of downward pH value adjustment, the pH value of each downward pH value adjustment is 0.9, the pH value of the reaction slurry after adjustment is constant for 10 minutes after each downward pH value adjustment, the slurry containing copper, zinc, aluminum and phosphorus is obtained, the obtained slurry is aged, the aging temperature is 78 ℃, the pH value is firstly controlled to be 13.0 during aging, the aging time is 0.15 hours, the aging pH value is controlled to be 8.8 after 1 part of aluminum chloride solution is added, the aging time is 0.1 hour, the pH value is controlled to be 7.0 again, the aging time is 0.1 hour, the operation process is repeated for 6 times, and the aging is finished. Filtering the aged slurry, drying the filter cake at 80 ℃ for 10 hours, adding a proper amount of graphite and water for rolling, tabletting and shaping, and washing with deionized water Washing to neutrality, and drying the washed molded product for the second time as follows: firstly, drying the material at 78 ℃ for 6.5 hours, uniformly spraying deionized water on the dried material, then drying, and repeating the processes of uniformly spraying the deionized water and drying for 6 times, wherein the volume ratio of the first sprayed deionized water to the dried material is 1.9:1, the drying temperature is 210 ℃, the drying time is 2.2 hours, and the volume ratio of the second spraying deionized water to the dried materials is 1.5:1, drying temperature 180 ℃ and drying time 2.0 hours, wherein the volume ratio of the third spraying deionized water to the dried materials is 1.0:1, the drying temperature is 190 ℃, the drying time is 1.6 hours, and the volume ratio of the fourth spraying deionized water to the dried materials is 1:1.3, drying temperature is 180 ℃, drying time is 2 hours, and the volume ratio of the fifth spraying deionized water to the dried materials is 1:1.5, drying temperature 190 ℃, drying time 2 hours. The volume ratio of the sprayed deionized water to the dried material for the sixth time is 1:2.0, drying temperature 190 ℃ and drying time 1.9 hours. The dried molded product was calcined at 350℃for 4 hours to obtain catalyst D. The composition, pore distribution and main properties are shown in Table 1.

Comparative example 1

According to the component content ratio of the catalyst A in the table 1, 334 g of Cu (NO ₃ ) ₂ ·3H ₂ O and 164 g Zn (NO) ₃ ) ₂ ·6H ₂ O is dissolved in deionized water to prepare a mixed solution. Adding deionized water into a reaction tank, adding the sodium metaaluminate solution and the mixed solution into the reaction tank in parallel, wherein the gel forming temperature is 60 ℃, the gel forming time is 1 hour, and the reaction pH value is 7.6, so as to obtain reaction slurry. Aging the slurry under stirring, wherein the aging pH value is 7.6, the aging temperature is 76 ℃ and the aging time is 2.5 hours, filtering the aged slurry, drying a filter cake at 90 ℃ for 10 hours, adding a proper amount of graphite and water for rolling, tabletting and forming, washing the formed material with deionized water to neutrality, drying the washed formed material at 100 ℃ for 8 hours, and roasting at 360 ℃ for 3 hours to obtain the catalyst E. The composition, pore distribution and main properties are shown in Table 1.

Comparative example 2

Reference F, identical in composition to the catalyst of example 1, was prepared according to the method disclosed in CN107774263a, following the procedure:

according to the catalyst composition of example 1, 334 g of Cu (NO ₃ ) ₂ ·3H ₂ O is dissolved in deionized water to prepare solution A. 164 g Zn (NO) ₃ ) ₂ ·6H ₂ O is dissolved in deionized water to prepare a mixed solution B. Adding deionized water into a reaction tank, and adding the sodium metaaluminate solution and the mixed solution A into the reaction tank in parallel flow, wherein the gelling temperature is 60 ℃, the gelling pH value is 7.6, and the gelling time is 1.0 hour, so as to obtain copper and aluminum-containing precipitate slurry I. Adding the sodium metaaluminate solution into the solution B under stirring, maintaining the gelling temperature at 60 ℃, controlling the pH value at 7.6 at the end, and controlling the gelling time at 1 hour to generate precipitate slurry II containing zinc and aluminum. Mixing the two precipitate-containing slurries. The materials are filtered after ageing, and the filter cake is subjected to hydrothermal treatment under the water vapor containing urea, wherein the conditions of the hydrothermal treatment are as follows: the molar ratio of urea to the total amount of active metal atoms is 7:1, the temperature is 230 ℃, the pressure is 6.0Mpa, the treatment time is 4 hours, the filter cake is dried at 90 ℃ for 10 hours, a proper amount of graphite and water are added for rolling, tabletting and shaping, the shaped material is washed by deionized water to be neutral, the shaped material is dried at 100 ℃ for 8 hours after washing, and the shaped material is roasted at 360 ℃ for 3 hours to obtain the catalyst F. The composition, pore distribution and main properties are shown in Table 1.

Comparative example 3

Reference G, identical in composition to the catalyst of example 1, was prepared according to the method disclosed in CN103372440a, as follows:

500Ml of water was added to the dissolution tank 1, and 334 g of Cu (NO) ₃ ) ₂ ·3H ₂ O and 164 g Zn (NO) ₃ ) ₂ ·6H ₂ O is dissolved to prepare an acidic working solution A, 500Ml of water is added into a dissolving tank 2, then sodium metaaluminate is added for dissolution to prepare an alkaline working solution B, and the solution A, the solution B and CO are stirred ₂ Adding the mixture into a reaction tank in parallel flow for gelling, and adding CO ₂ The concentration is 90v%, the gel forming reaction temperature is 60 ℃, the gel forming time is 1 hour, and the pH value of the gel forming slurry is controlled to be 7.6. Glue formingCO addition during the process ₂ Total amount of gas and Al in alkaline working solution B ₂ O ₃ The molar ratio was 3.5. Aging at pH 7.6 and 75 deg.C for 2.5 hr, filtering, washing with deionized water, drying filter cake at 100deg.C for 8 hr, calcining at 360 deg.C for 3 hr, adding graphite and water, tabletting, and tabletting. The composition, pore distribution and main properties are shown in Table 1.

Comparative example 4

Reference H, identical in composition to the catalyst of example 1, was prepared according to the method disclosed in CN110935457a, as follows:

334 g of Cu (NO) ₃ ) ₂ ·3H ₂ O and 164 g Zn (NO) ₃ ) ₂ ·6H ₂ O is dissolved in deionized water, 116 g of hydroxyethylidene diphosphonic acid is added to be evenly mixed to prepare a mixed solution A, cu (NO) ₃ ) ₂ ·3H ₂ O and AlCl ₃ ·6H ₂ O is dissolved in deionized water to prepare a mixed solution B. Adding deionized water into a reaction tank, and adding the sodium metaaluminate solution and the mixed solution A into the reaction tank in parallel flow, wherein the gelling temperature is 60 ℃, the gelling pH value is 7.5, and the gelling time is 0.9 hour, so as to obtain slurry I. Slurry I was aged with stirring at 190 rpm at 75℃and pH 7.2 for 0.7 hours. After the aging is finished, the mixed solution B and the sodium carbonate solution are added into the aged slurry I in parallel, the molar ratio of the sodium carbonate to the total amount of copper and zinc is 2.0, the gelling temperature is 60 ℃, the pH value is 9.2, the gelling time is 2.0 hours, the slurry II is obtained, the slurry II is aged under the stirring condition, the stirring speed is 400 r/min, the aging temperature is 75 ℃, the pH value is 7.6, the aging time is 2.5 hours, the aged slurry II is filtered, the filter cake is washed by deionized water, the filter cake is dried at 100 ℃ for 8 hours, the roasting is performed at 360 ℃ for 3 hours, and a proper amount of graphite and water are added into the roasted material to form a tablet, so that the catalyst H is obtained. The composition, pore distribution and main properties are shown in Table 1.

Comparative example 5

In the same way as in example 1, the reference agent I is prepared, only deionized water is added in the reaction tank during the preparation process, castor oil phosphate is not added, and meanwhile, carbon dioxide gas is not introduced during the reaction process, and the specific reaction process is as follows:

334 g of Cu (NO) ₃ ) ₂ ·3H ₂ O and 164 g Zn (NO) ₃ ) ₂ ·6H ₂ O is dissolved in deionized water to prepare Zn and Cu containing solution. AlCl is added ₃ ·6H ₂ O is dissolved in deionized water to prepare aluminum chloride solution, and Al in the aluminum chloride solution accounts for the total Al in the obtained copper-zinc catalyst and is Al ₂ O ₃ 30% by volume and aliquoted into 5 parts by volume. Deionized water is added into a reaction tank, and sodium metaaluminate solution (containing Al ₂ O ₃ 21 g/L) and Zn and Cu-containing solution are added into a reaction tank in parallel, the gelling temperature is 60 ℃, the pH value is initially controlled to be 13.1, the final pH value at the end is adjusted to be 7.5 by 7 times of downward pH value adjustment, the pH value of each downward pH value adjustment is 0.8, the pH value of the reaction slurry is controlled to be constant for 8 minutes after each downward pH value adjustment, the slurry containing copper, zinc and aluminum is obtained after the reaction is finished, the obtained slurry is aged, the aging temperature is 76 ℃, the pH value is firstly controlled to be 13.2 during aging, the aging time is 0.2 hour, the aging pH value is controlled to be 9.5 after 1 equal part of aluminum chloride solution is added, the aging time is 0.15 hour, the pH value is then controlled to be 7.6, the aging time is 0.15 hour, the operation process is repeated for 5 times, and the aging is finished. Filtering the aged slurry, drying the filter cake at 90 ℃ for 10 hours, adding a proper amount of graphite and water for rolling, and tabletting and forming. Washing the molding material with deionized water to neutrality, and drying the washed molding material for the second time as follows: firstly, drying the material at 70 ℃ for 5.0 hours, uniformly spraying deionized water on the dried material, then drying, and repeating the processes of uniformly spraying the deionized water and drying for 6 times, wherein the volume ratio of the first sprayed deionized water to the dried material is 1.5:1, drying temperature 180 ℃ and drying time 2.0 hours, wherein the volume ratio of the second spraying deionized water to the dried materials is 1.2:1, the drying temperature is 200 ℃, the drying time is 2.5 hours, and the volume ratio of the third spraying deionized water to the dried materials is 1:1, drying temperature 180 ℃ and drying time 2.0 hours, wherein the volume ratio of the fourth spraying deionized water to the dried materials is 1:1.2 drying temperature And when the drying time is 1.7 at 150 ℃, the volume ratio of the deionized water sprayed for the fifth time to the dried materials is 1:1.8, drying temperature 170 ℃ and drying time 2 hours, wherein the volume ratio of the sprayed deionized water to the dried material for the sixth time is 1:2.5, drying temperature 170 ℃ and drying time 2 hours. The dried molded product was calcined at 360℃for 3 hours to obtain catalyst I. The composition, pore distribution and main properties are shown in Table 1.

Comparative example 6

As in example 1, all aluminum chloride solutions were added at one time during the aging process, and the aging pH value was set to a fixed value, and the preparation process was as follows:

334 g of Cu (NO) ₃ ) ₂ ·3H ₂ O and 164 g Zn (NO) ₃ ) ₂ ·6H ₂ O is dissolved in deionized water to prepare Zn and Cu containing solution. AlCl is added ₃ ·6H ₂ O is dissolved in deionized water to prepare aluminum chloride solution, and Al in the aluminum chloride solution accounts for the total Al in the obtained phosphorus-containing copper-zinc catalyst and is Al ₂ O ₃ 30% of the total. Adding deionized water and castor oil phosphate with the mole ratio of 1.0 to the total Al atoms in sodium metaaluminate into a reaction tank, and introducing CO with the concentration of 50% by volume into the reaction tank solution ₂ Gas, CO ₂ The flow rate of the gas was 60ml/min. Sodium metaaluminate solution (containing Al ₂ O ₃ 21 g/L) and Zn and Cu-containing solution are added into a reaction tank in parallel, the gelling temperature is 60 ℃, the pH value is initially controlled to be 13.1, the final pH value at the end is adjusted to be 7.5 by reducing the pH value for 7 times, the pH value of each reduced pH value is 0.8, after each reduced pH value is adjusted, the pH value of the reaction slurry is controlled to be constant for 8 minutes, after the reaction is finished, slurry containing copper, zinc, aluminum and phosphorus is obtained, the obtained slurry is aged, all aluminum chloride solution is added at the beginning of aging, the aging temperature is 76 ℃, the pH value at the time of aging is controlled to be 7.6, and the aging is finished after 2.5 hours. Filtering the aged slurry, drying the filter cake at 90 ℃ for 10 hours, adding a proper amount of graphite and water for rolling, and tabletting and forming. Washing the molding material with deionized water to neutrality, and drying the washed molding material for the second time as follows: drying the material at 70deg.C for 5.0 hr, and spraying the dried material The ionized water is dried, deionized water is uniformly sprayed and the drying process is repeated for 6 times, wherein the volume ratio of the first sprayed deionized water to the dried material is 1.5:1, drying temperature 180 ℃ and drying time 2.0 hours, wherein the volume ratio of the second spraying deionized water to the dried materials is 1.2:1, the drying temperature is 200 ℃, the drying time is 2.5 hours, and the volume ratio of the third spraying deionized water to the dried materials is 1:1, drying temperature 180 ℃ and drying time 2.0 hours, wherein the volume ratio of the fourth spraying deionized water to the dried materials is 1:1.2, the drying temperature is 150 ℃, and when the drying time is 1.7, the volume ratio of the deionized water sprayed for the fifth time to the dried materials is 1:1.8, drying temperature 170 ℃ and drying time 2 hours, wherein the volume ratio of the sprayed deionized water to the dried material for the sixth time is 1:2.5, drying temperature 170 ℃ and drying time 2 hours. The dried molded product was calcined at 360℃for 3 hours to obtain catalyst J. The composition, pore distribution and main properties are shown in Table 1.

Comparative example 7

As in example 1, the second drying after washing the molded article in the preparation process uses the first drying condition (conventional drying condition), and the preparation process is as follows:

334 g of Cu (NO) ₃ ) ₂ ·3H ₂ O and 164 g Zn (NO) ₃ ) ₂ ·6H ₂ O is dissolved in deionized water to prepare Zn and Cu containing solution. AlCl is added ₃ ·6H ₂ O is dissolved in deionized water to prepare aluminum chloride solution, and Al in the aluminum chloride solution accounts for the total Al in the obtained phosphorus-containing copper-zinc catalyst and is Al ₂ O ₃ 30% by volume and aliquoted into 5 parts by volume. Adding deionized water and castor oil phosphate with the mole ratio of 1.0 to the total Al atoms in sodium metaaluminate into a reaction tank, and introducing CO with the concentration of 50% by volume into the reaction tank solution ₂ Gas, CO ₂ The flow rate of the gas was 60ml/min. Sodium metaaluminate solution (containing Al ₂ O ₃ 21 g/L) and Zn and Cu-containing solution are added into a reaction tank in parallel, the gel forming temperature is 60 ℃, the pH value is initially controlled to be 13.1, the final pH value at the end is adjusted to be 7.5 by reducing the pH value for 7 times, the pH value of each reduction is 0.8, the pH value of the reaction slurry is controlled to be constant for 8 minutes after each reduction to the adjustment value,after the reaction is finished, slurry containing copper, zinc, aluminum and phosphorus is obtained, the obtained slurry is aged at the temperature of 76 ℃, the pH value is controlled to be 13.2 at first during aging, after the aging time is 0.2 hour, 1 equal part of aluminum chloride solution is added, the aging pH value is controlled to be 9.5, after the aging time is 0.15 hour, the pH value is controlled to be 7.6, the aging time is 0.15 hour, the operation process is repeated for 5 times, and the aging is finished. Filtering the aged slurry, drying the filter cake at 90 ℃ for 10 hours, adding a proper amount of graphite and water for rolling, and tabletting and forming. Washing the molding material with deionized water to neutrality, drying the washed molding material at 90 deg.c for 10 hr, and roasting the dried molding material at 360 deg.c for 3 hr to obtain catalyst K. The composition, pore distribution and main properties are shown in Table 1.

Example 5

Grinding the methanol synthesis catalyst to 16-40 mesh, and using low concentration hydrogen (H) ₂ /N ₂ =3/97 (volume ratio)) is reduced for 16-25 h, the maximum reduction temperature is 235 ℃. The activity of the catalyst was evaluated on a micro fixed bed reactor. The catalyst loading was 5ml and the feed gas composition was CO/H ₂ /CO ₂ /N ₂ =13/70/6/11 (volume ratio), reaction pressure 5.0Mpa, space velocity 10000h ^-1 The reaction temperature was 245℃and CO and CO were measured ₂ The conversion of (2) is the initial activity of the catalyst. Then the catalyst is heat treated for 5 hours at 445 ℃ in the synthetic atmosphere, and then the temperature is reduced to 250 ℃ to measure CO and CO ₂ The conversion of (2) is the activity after heat treatment, i.e., heat resistance. The product was analyzed by gas chromatograph to yield the space-time yield g.Ml of methanol ^-1 ·h ^-1 I.e. grams of methanol produced per ml of catalyst per hour, the results are shown in table 4.

From tables 1 to 3, it can be seen that the catalyst of the invention has good metal dispersion, thereby improving the synergistic effect between Cu and ZnO, the average pore diameter is from large to small from the outer surface layer of the catalyst to the central core, the particle diameter of copper is mainly concentrated at 7-10 nm, the catalyst has high activity and selectivity, and the experimental result shows that the methanol synthesis catalyst of the invention has high activity, heat resistance and excellent selectivity.

TABLE 1 catalyst composition and Properties

Table 1, below

Table 2 average particle diameter and particle diameter distribution of the core-shell composite oxide particles of the catalysts obtained in each example

Continuous table 2

TABLE 3 dispersity and specific surface area of metallic copper

S _Cu Specific surface area of copper, D _Cu For copper dispersity

TABLE 4 evaluation of catalyst Activity and Heat resistance test results

Claims

1. The preparation method of the phosphorus-containing copper-zinc catalyst is characterized by comprising the following steps: (1) Adding deionized water and phosphate into a gel forming reaction tank, and continuously introducing CO ₂ The Zn, cu-containing solution and the sodium metaaluminate solution are subjected to parallel flow gelling reaction under stirring to obtain slurry; (2) Continuously ageing the slurry obtained in the step (1) for n times with three-stage decreasing pH value, wherein each time is carried out on the second stageAdding 1/n Al-containing solution after the primary pH value aging, carrying out solid-liquid separation on the materials obtained after the aging, carrying out a first drying and tabletting forming process on the solid phase to obtain a formed product, washing, second drying and roasting to obtain a phosphorus-containing copper-zinc catalyst; wherein, the second drying process is as follows: a. firstly, drying the materials at the temperature of 60-100 ℃ for 1.0-8.5 hours; b. uniformly spraying water on the material obtained in the step a, wherein the volume ratio of water to dry material is 1:4~4:1, then drying for 0.5-4.0 hours at the temperature of 150-280 ℃; c. and (c) repeating the process of the step b for 2-9 times.

2. The method according to claim 1, characterized in that: in the Zn and Cu-containing solution in the step (1), the concentration of the soluble copper salt is Cu ²⁺ 0.4 to 3.5mol/L, and the concentration of the soluble zinc salt is calculated as Zn ²⁺ Counting to be 0.2-3.0 mol/L; the concentration of the sodium metaaluminate solution is Al ₂ O ₃ The weight of the feed is 10-90 g/L.

3. The method according to claim 1, characterized in that: the phosphate ester in the step (1) is one or more of octadecyl ether phosphate ester, alkylphenol ether phosphate ester, isomeric tridecyl ether phosphate ester, lauryl ether phosphate ester, castor oil phosphate ester, octadecyl phosphate ester and lauryl phosphate ester.

4. The method according to claim 1, characterized in that: the mole ratio of the phosphate ester in the step (1) to the Al in the sodium metaaluminate solution in the step (1) is 0.2: 1-2.0: 1.

5. the method according to claim 1, characterized in that: CO addition as described in step (1) ₂ The gas concentration is 40-70 v%; CO ₂ The flow rate of the gas is 30-120 mL/min.

6. The method according to claim 1, characterized in that: the gelling reaction conditions in the step (1) are as follows: the reaction temperature is 30-90 ℃, the pH value is initially controlled to be 10.0-14.0, the final pH value is 7.0-8.5 at the end, and the gel forming reaction time is 0.5-6.0 hours.

7. The method according to claim 6, wherein: the pH value is adjusted down from the initial value to the final pH value by adopting a method of multiple times, wherein the method of multiple times of adjustment is that the pH value is adjusted down to the current required value, and the pH value of the reaction slurry is kept constant until the next adjustment is started, and the number of times of adjustment is 2-10.

8. The time used for each down-regulation process may be the same or different, preferably the same.

9. The method according to claim 1, characterized in that: in the step (2), the added Al accounts for the total Al in the obtained synthetic methanol catalyst and is Al ₂ O ₃ 5% -45% of the meter, preferably 6% -40%; when the Al-containing solution is prepared, the aluminum source is soluble aluminum salt, and the aluminum source is divided into n parts by volume, wherein n is an integer of 2-8.

10. The method according to claim 1, characterized in that: the three-stage decreasing pH aging process in the step (2) is specifically as follows: the aging temperature is 60-98 ℃; the first stage, wherein the pH value is 11.0-13.5, aging is carried out for 0.05-0.5 hours, and 1/n of Al-containing solution is added after the first stage aging is finished; second, adjusting the pH value to 8.5-10.5, and aging for 0.05-0.5 hours; thirdly, adjusting the pH to 5.5-8.3, and aging for 0.05-0.5 hours; wherein n is an integer of 2 to 8.

11. The method according to claim 1, characterized in that: adding an extrusion aid in the forming process in the step (2), wherein the extrusion aid is a substance beneficial to extrusion forming, and the consumption of the extrusion aid accounts for 1-10wt% of the total material dry basis; the synthesized phosphorus-containing copper-zinc catalyst is in a cylindrical solid particle shape, the particle size of the catalyst particle is 2-12 mm, and the length of the catalyst particle is 1-8 mm.

12. The method according to claim 1, characterized in that: washing the washing liquid in the step (2) to be neutral by deionized water; the first drying condition: drying at 50-150 ℃ for 0.5-24.0 hours; the roasting conditions are as follows: roasting for 1-16 hours at 300-360 ℃.

13. The method according to claim 1, characterized in that: in the second drying process in the step (2), the volume ratio of the first water adding volume to the dried material is greater than 1:1, the volume ratio of the last water adding volume to the dry material is less than 1:1, the volume ratio of the water adding volume to the drying material is sequentially reduced along with the increase of the drying times.

14. The phosphorus-containing copper-zinc catalyst is characterized by comprising the following components by weight of the catalyst: 20 to 65 percent of CuO, 10 to 35 percent of ZnO and 10 to 35 percent of Al ₂ O ₃ 8% -35%, P ₂ O ₅ Counting to be 2% -16%; the specific surface area of the metallic copper in the reduced catalyst is 45-140 m ² The dispersity of the metal copper is 20-50 percent; the average grain diameter of the metal copper is 7-10 nm; the particle size distribution of the metallic copper particles is as follows: the particle number of the particles with the particle size of less than 7nm accounts for 5% -17% of the total particle number, the particle number of the particles with the particle size of 7 nm-10 nm accounts for 62% -85% of the total particle number, and the particle number of the particles with the particle size of more than 10nm accounts for 5% -15% of the total particle number.

15. A phosphorus-containing copper zinc catalyst according to claim 13, characterized in that: the catalyst is solid particles, and the average pore diameter is from large to small from the outer surface layer of the catalyst to the central core; the catalyst particles comprise an outer surface layer, an intermediate layer and a central core, wherein the average pore diameter is reduced in a gradient manner, namely, the average pore diameter of the outer surface layer is larger than that of the intermediate layer, and the average pore diameter of the intermediate layer is larger than that of the central core; the average pore diameter of the outer surface layer is 12-18 nm, the average pore diameter of the middle layer is 8-12 nm, the average pore diameter of the central core is 4-8 nm, and the length from the outermost edge to the central point is R on the cross section of the catalyst particle; the thickness of the outer surface layer is 0.2R-0.4R, the thickness of the middle layer is 0.2R-0.5R, and the rest is the central core.

16. Use of the phosphorus-containing copper zinc catalyst of claim 13 or 14 in a methanol synthesis reaction under the process conditions: the reaction temperature is 210-320 ℃, the pressure is 2.0-10 MPa, and the volume space velocity is 2000-15000 h ^-1 。