Preparation method of high-selectivity high-strength methanol synthesis catalyst

Abstract

The invention discloses a preparation method of a high-selectivity and high-strength methanol synthesis catalyst, and belongs to the technical field of catalysts. The method adopts a three-step precipitation method to prepare a catalyst precursor, specifically, after zirconium and aluminum form a precipitate 1 together, zinc continues to precipitate on the basis of the precipitate 1 to form a precipitate 2, and finally copper, zinc and aluminum continue to precipitate on the basis of the precipitate 2. The finally prepared methanol synthesis catalyst has excellent selectivity and strength while having low-temperature activity and stability. The methanol synthesis catalyst prepared by the method can be widely applied to methanol synthesis devices with annual output of 600,000 tons and above.

Description

Technical Field

[0001] The invention relates to the technical field of catalyst production, and in particular to a method for preparing a high-selectivity and high-strength methanol synthesis catalyst. Background Art

[0002] Methanol to olefins (MTO, MTP) is the main growth driver of the methanol industry, which drives the development of methanol synthesis units towards large-scale and super-large directions.

[0003] When methanol synthesis units develop towards large-scale and super-large-scale, the average temperature of the catalyst bed for synthesizing methanol is above 280°C for a long time, and the temperature of individual hot spots exceeds 300°C, which puts higher requirements on the stability of the catalyst. Preliminary tests show that when the operating temperature exceeds 280°C, the content of liquid by-products increases sharply. If the catalyst selectivity is not high, the excessive content of liquid by-products will not only increase the distillation load, but also affect the product quality and raw material utilization rate; in addition, catalyst strength is also an important indicator. When the catalyst has excellent strength, the catalyst is not easy to pulverize in various links, which is conducive to the long-term use of the catalyst.

[0004] In the face of the development of methanol synthesis equipment towards large-scale and super-large-scale, the catalyst for synthesizing methanol must have excellent thermal stability and high-temperature selectivity. Generally speaking, when the catalyst has excellent low-temperature activity and stability, the high-temperature selectivity is not good. Therefore, it is urgent to develop a methanol synthesis catalyst that can take into account both low-temperature activity and stability while also having excellent high-temperature selectivity. In addition, this methanol synthesis catalyst should also have excellent strength. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a high-selectivity and high-strength methanol synthesis catalyst in response to the above technical problems. The catalyst prepared by this method has high selectivity and high strength when used for methanol synthesis, which better solves the technical problem of unsatisfactory selectivity and strength of existing catalysts.

[0006] In order to achieve the above invention object, the specific technical solution of the present invention is:

[0007] A method for preparing a high-selectivity and high-strength methanol synthesis catalyst comprises the following steps:

[0008] Step 1: dissolving aluminum nitrate and zirconium nitrate in water to form a salt solution A1; dissolving zinc nitrate in water to form a salt solution A2; dissolving zinc nitrate, copper nitrate and aluminum nitrate in water to form a mixed salt solution A3; dissolving sodium carbonate solution in water to form an alkaline solution B1;

[0009] Step 2: using the salt solution A1 and the alkaline solution B1 to react in parallel to form a precipitate 1, and then aging the precipitate 1;

[0010] Step 3: using the aged precipitate 1, salt solution A2 and alkaline solution B1 to react in parallel to form precipitate 2, and controlling the feed rates of precipitate 1 and salt solution A2 so that the precipitate 1 and salt solution A2 react at the same time, and aging the precipitate 2;

[0011] Step 4: using the aged precipitate 2, the salt solution A3 and the alkaline solution B1 to react in parallel to form the precipitate 3, and controlling the feed rates of the precipitate 2 and the salt solution A3 so that the precipitate 2 and the salt solution A3 are completed at the same time, and the precipitate 3 is aged;

[0012] Step 5: The aged precipitate 3 is washed and filtered, and graphite is added to the obtained filter cake for slurrying, and then dried, calcined and formed to obtain a methanol synthesis catalyst.

[0013] Furthermore, in the methanol synthesis catalyst obtained by the above-mentioned method for preparing a high-selectivity and high-strength methanol synthesis catalyst, the content of CuO is 56.4-64.6% (specifically 56.4%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 64.6%, etc.), the content of ZnO is 17.1-25.4% (specifically 17.1%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 25.4%, etc.), and the content of Al is 1. 2 O 3 16.3-19.8% (specifically 16.3%, 17%, 17.5%, 18%, 18.5%, 19%, 19.8%, etc.), ZrO 2 It is 0.3% to 1.1% (specifically 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, etc.), and the sum of the total mass percentages is 100%.

[0014] Preferably, the methanol synthesis catalyst obtained by the above-mentioned method for preparing a high-selectivity and high-strength methanol synthesis catalyst also contains graphite, and the graphite accounts for 1-3% of the total mass of the catalyst (specifically 1%, 1.5%, 2.0%, 2.5%, 3%, etc.).

[0015] As a preferred embodiment of the present application, in step 1 of the method for preparing a high-selectivity and high-strength methanol synthesis catalyst, in the salt solution A1, the molar amount of zirconium accounts for 0.8% to 2.5% of the total molar amount of aluminum and zirconium (specifically 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, 2.4%, 2.5%, etc.); in the salt solution A2, the molar concentration of zinc is 0.1 to 0.5 mol / L (specifically 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, etc.); in the salt solution A3, Al 3+ The molar amount of Cu 2+ 、Zn 2+ and Al 3+ 0.5% to 3.5% of the total molar amount (specifically 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, etc.), Cu 2+ and Zn 2+ The molar ratio is 3-4:1 (specifically 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4:1, etc.).

[0016] As a better implementation mode in the present application, in step 2 of the method for preparing a high-selectivity and high-strength methanol synthesis catalyst, the parallel flow reaction temperature is controlled to be 60-90°C (specifically 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc.), and the pH value is 7-9 (specifically 7, 7.5, 8, 8.5, 9); the aging temperature of the precipitate 1 is the same as the parallel flow reaction temperature, and the time is 2-4h (specifically 2h, 2.5h, 3h, 3.5h, 4h, etc.).

[0017] As a better implementation mode in the present application, in step 3 of the preparation method of a high-selectivity and high-strength methanol synthesis catalyst, the parallel flow reaction temperature is controlled to be 60-90°C (specifically 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc.), and the pH value is 6-8 (specifically 6, 6.5, 7, 7.5, 8, etc.); the aging temperature of the precipitate 2 is the same as the parallel flow reaction temperature, and the aging time is 1-2h (specifically 1h, 1.5h, 2h, etc.).

[0018] As a better implementation mode in the present application, in step 4 of the method for preparing a high-selectivity and high-strength methanol synthesis catalyst, the parallel flow reaction temperature is controlled to be 60-80°C (specifically 60°C, 65°C, 70°C, 75°C, 80°C, etc.), and the pH value is 6-8 (specifically 6, 6.5, 7, 7.5, 8, etc.); the aging temperature of the precipitate 3 is the same as the parallel flow reaction temperature, and the time is 1h-2h (specifically 1h, 1.5h, 2h, etc.).

[0019] As a better embodiment of the present application, in step 5 of the method for preparing a high-selectivity and high-strength methanol synthesis catalyst, ethanol is added to the graphite and slurried together, and the amount of ethanol added accounts for 10% to 20% of the total mass of the catalyst (specifically 10%, 15%, 20%, etc.); the drying temperature is 100 to 120° C. (specifically 100° C., 105° C., 110° C., 115° C., 120° C., etc.), and the drying time is 3h to 5h (specifically 3h, 4h, 5h, etc.); N is introduced during calcination. 2 The calcination temperature is 350°C to 500°C (specifically 100°C, 105°C, 110°C, 115°C, 120°C, etc.), and the calcination time is 4 to 6h (specifically 4h, 5h, 6h, etc.).

[0020] The second invention objective of the present invention is to protect a high-selectivity and high-strength methanol synthesis catalyst prepared by any of the above methods or combined steps.

[0021] The third invention objective of the present invention is to protect the use of the above-mentioned catalyst in methanol synthesis.

[0022] Compared with the prior art, the positive effects of the present invention are embodied in:

[0023] (1) The present invention uses zirconium and aluminum to form precipitate 1 together, then continues to precipitate zinc on the basis of precipitate 1 to form precipitate 2, and finally continues to precipitate copper, zinc, and aluminum on the basis of precipitate 2, a total of three steps of precipitation. The catalyst prepared by such a three-step precipitation method ultimately has the characteristics of high stability, high activity, and high selectivity. This is because zirconium and aluminum are precipitated together, and after later calcination, zirconium oxide-modified alumina can be formed, which improves the stability of alumina. At the same time, it also has the characteristics of a large specific surface area of ​​alumina. Therefore, precipitate 1 can be the second step Zn 2+ Provide more dispersion sites. This part of zinc is dispersed around the modified alumina in the form of extremely small grains through the later calcination of zinc oxide. Therefore, the second step precipitate formed still has the characteristics of large specific area, and there are still many scattered Zn on the surface. 2+ The precipitate is then subjected to the third step of copper-zinc-aluminum precipitation, and the second step of Zn 2 + Precipitation, third step Cu2+ The dispersion will be more uniform, the distribution range of the CuO grain size formed later will be narrow, and the interaction between copper and zinc will be stronger. In addition, the first step of precipitation neutralizes the acidity of the aluminum oxide surface by zirconium oxide, so the catalyst has the characteristics of high stability, high activity and high selectivity.

[0024] (2) Graphite is added to the filter cake for slurrying, and a certain proportion of ethanol is added during the slurrying process. Since ethanol is added to the slurry, the surface tension of water is reduced, making it easier to infiltrate graphite. Compared with the traditional process of adding graphite to the roasting powder, the dispersion of graphite is improved, and the strength of the catalyst can be significantly improved under the same molding pressure. In addition, the graphite particles are more evenly filled between the catalyst particles, which not only plays a certain skeleton support structure, but also helps to improve the stability of the catalyst due to the good thermal stability of graphite.

[0025] (3) The methanol synthesis catalyst prepared by the present invention can be widely used in methanol synthesis units with an annual output of 600,000 tons or more. DETAILED DESCRIPTION

[0026] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0027] Any feature disclosed in this specification (including claims and abstract), unless otherwise stated, may be replaced by other equivalent or alternative features having similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0028] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0029] In the present application, unmarked % indicates mass percentage.

[0030] In the present invention, some conventional operating equipment, devices and components are omitted or only briefly described.

[0031] Embodiment 1:

[0032] 125.09 g Al(NO 3 ) 3 9H 2 O and 3.83g Zr(NO 3 ) 4 ·5H 2 O was dissolved in deionized water and the volume was adjusted to 680 ml to form salt solution A1; 12.63 g Zn(NO 3 ) 2 6H 2O was dissolved in deionized water and the volume was adjusted to 200 ml to form salt solution A2; 190.23 g Cu(NO 3 ) 2 ·3H 2 O, 50.51gZn(NO 3 ) 2 6H 2 O and 22.08 g Al(NO 3 ) 3 9H 2 O was dissolved in deionized water and the volume was adjusted to 1000 ml to form the salt solution A3 required for precipitation; 321.18 g NaCO 3 Dissolve in deionized water and adjust the volume to 2500 ml to form the alkaline solution B1 required for precipitation.

[0033] After preheating the salt solution A1 and the alkaline solution B1 to 60°C, under strong stirring, the salt solution A1 and the alkaline solution B1 are simultaneously added dropwise to a reaction tank filled with deionized water to form a precipitate 1. The reaction temperature is controlled at 60°C and the pH value is 8.8-9.2. After the addition of solution A1 is completed, the addition of alkali B1 is stopped and constant temperature aging at 60°C is continued for 5 hours.

[0034] Filter the aged precipitate 1, add the precipitate 1 to the mixed solution A2 to form a highly dispersed suspension slurry C, preheat the suspension slurry C to 60°C, and then, under strong stirring, simultaneously add the suspension slurry C and the alkaline solution B1 dropwise into a reaction tank filled with a certain amount of deionized water to form precipitate 2. The reaction temperature is controlled at 60°C and the pH value is 7.8-8.2. After the addition of the suspension slurry C is completed, stop adding the alkali B1 and continue aging at 60°C for 3 hours.

[0035] After preheating the salt solution A3 to 60°C, the aged precipitate 2, the salt solution A3 and the alkaline solution B1 are simultaneously added dropwise to a reaction tank filled with a certain amount of deionized water under strong stirring to form a precipitate 3. The reaction temperature is controlled at 60°C and the pH value is 7.8-8.2. After the addition of solution A3 and precipitate 2 is completed, the addition of alkali B1 is stopped. After the reaction is completed, the precipitate 3 is aged for 30 minutes at 60°C.

[0036] The aged precipitate 3 was filtered and washed with deionized water until no Na+ was detected. 1 g of graphite was added to the obtained filter cake and slurried. After slurrying, it was dried at 90°C for 6 h, and then calcined in a muffle furnace at 350°C for 6 h. The calcined powder was molded to obtain a methanol synthesis catalyst, which was numbered as sample 1.

[0037] Example 2

[0038] 125.09 g Al(NO 3 ) 3 9H2 O and 3.83g Zr(NO 3 ) 4 ·5H 2 O was dissolved in deionized water and the volume was adjusted to 680 ml to form salt solution A1; 12.63 g Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water and the volume was adjusted to 200 ml to form salt solution A2; 190.23 g Cu(NO 3 ) 2 ·3H 2 O, 50.51gZn(NO 3 ) 2 6H 2 O and 22.08 g Al(NO 3 ) 3 9H 2 O was dissolved in deionized water and the volume was adjusted to 1000 ml to form the salt solution A3 required for precipitation; 321.18 g NaCO 3 Dissolve in deionized water and adjust the volume to 2500 ml to form the alkaline solution B1 required for precipitation.

[0039] After preheating the salt solution A1 and the alkaline solution B1 to 90°C, the salt solution A1 and the alkaline solution B1 are simultaneously added dropwise into a reaction tank containing a certain amount of deionized water under strong stirring to form a precipitate 1. The reaction temperature is controlled at 90°C and the pH value is 6.8-7.2. After the addition of solution A1 is completed, the addition of alkali B1 is stopped and constant temperature aging at 90°C is continued for 1 hour.

[0040] After preheating the salt solution A2 to 90°C, the aged precipitate 1, the salt solution A2 and the alkaline solution B1 are simultaneously added dropwise to a reaction tank filled with a certain amount of deionized water under strong stirring to form a precipitate 2. The reaction temperature is controlled at 90°C and the pH value is 6.8-7.2. After the addition of solution A2 and precipitate 1 is completed, the addition of alkali B1 is stopped and the aging is continued at 90°C for 30 minutes.

[0041] After preheating the salt solution A3 to 70°C, the aged precipitate 2, the salt solution A3 and the alkaline solution B1 are simultaneously added dropwise to a reaction tank containing a certain amount of deionized water under strong stirring to form a precipitate 3. The reaction temperature is controlled at 80°C and the pH value is 5.8-6.2. After the addition of solution A3 and precipitate 2 is completed, the addition of alkali B1 is stopped. After the reaction is completed, the precipitate 3 is aged for 3 hours at 80°C.

[0042] The aged precipitate 3 was filtered and washed with deionized water until no Na +, add 1 g of graphite to the obtained filter cake and slurry it. After slurrying, dry it at 120°C for 2 hours, then calcine it at 500°C in a muffle furnace for 4 hours, and shape the calcined powder to obtain a methanol synthesis catalyst, which is numbered as sample 2.

[0043] Example 3

[0044] Based on Example 1, the only difference is that 115.10 g Al(NO 3 ) 3 9H 2 O and 1.04gZr(NO 3 )4·5H 2 O was dissolved in deionized water and the volume was adjusted to 610 ml to form salt solution A1; 18.76 g Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water and the volume was adjusted to 100 ml to form salt solution A2; 177.95 g Cu(NO 3 ) 2 ·3H 2 O, 75.02g Zn(NO 3 ) 2 6H 2 O and 6.06g Al(NO 3 ) 3 9H 2 O is dissolved in deionized water and the volume is adjusted to 990 ml to form the salt solution A3 required for precipitation; the preparation of the alkaline solution B1 is the same as in Example 1.

[0045] When forming precipitate 1, the preheating temperature of salt solution A1 and alkaline solution B1 is 80°C, the reaction temperature is 80°C, the pH value is 6.8-7.2, and the aging is carried out at a constant temperature of 80°C for 6 hours; when forming precipitate 2, the preheating temperature of suspension slurry C is 80°C, the reaction temperature is 80°C, the pH value is 6.8-7.2, and the aging is carried out at a constant temperature of 80°C for 3 hours; when forming precipitate 3, the preheating temperature of salt solution A3 is 70°C, the reaction temperature is 70°C, the pH value is 7.8-8.2, and the aging is carried out at a constant temperature of 70°C for 3 hours; 3 g of graphite is added to the obtained filter cake and slurried, and the remaining steps are the same as those in Example 2. The catalyst finally obtained is numbered sample 3.

[0046] Example 4

[0047] Based on Example 2, the only difference is that 119.94 g Al(NO 3 ) 3 9H 2 O and 1.04gZr(NO 3 )4·5H 2O was dissolved in deionized water and the volume was adjusted to 640 ml to form salt solution A1; 9.38 g Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water and the volume was adjusted to 350 ml to form salt solution A2; 177.95 g Cu(NO 3 ) 2 ·3H 2 O, 84.40 g Zn(NO 3 ) 2 6H 2 O and 1.21 g Al(NO 3 ) 3 9H 2 O is dissolved in deionized water and the volume is fixed to 1000 ml to form the salt solution A3 required for precipitation; the preparation of the alkaline solution B1 is the same as in Example 2.

[0048] When forming precipitate 1, the preheating temperature of salt solution A1 and alkaline solution B1 is 70°C, the reaction temperature is 70°C, the pH value is 7.8-8.2, and the aging is carried out at a constant temperature of 70°C for 1h; when forming precipitate 2, the preheating temperature of salt solution A2 is 70°C, the reaction temperature is 70°C, the pH value is 8.8-9.2, and the aging is carried out at a constant temperature of 70°C for 30min; when forming precipitate 3, the preheating temperature of salt solution A3 is 70°C, the reaction temperature is 70°C, the pH value is 5.8-6.2, and the aging is carried out at a constant temperature of 70°C for 30min; 3g of graphite is added to the obtained filter cake and slurried, and the remaining steps are the same as those in Example 2. The prepared catalyst is numbered as sample 4.

[0049] Example 5

[0050] Based on Example 1, the only difference is that 120.72 g Al(NO 3 ) 3 9H 2 O and 3.51gZr(NO 3 )4·5H 2 O was dissolved in deionized water and the volume was adjusted to 650 ml to form salt solution A1; 19.64 g Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water and the volume was adjusted to 130 ml to form salt solution A2; 173.15 g Cu(NO 3 ) 2 ·3H 2 O, 71.07 g Zn(NO 3 ) 2 6H 2 O and 13.00 g Al(NO 3 )3 9H 2 O is dissolved in deionized water and the volume is adjusted to 980 ml to form the salt solution A3 required for precipitation;

[0051] The aging time of precipitate 1 is 2 h; the aging time of precipitate 2 is 30 min; the aging time of precipitate 3 is 3 h; 2 g of graphite and 10 g of ethanol are added to the obtained filter cake for slurrying, and the drying time after slurrying is 5 h. The remaining steps are the same as in Example 1, and the prepared catalyst is numbered as Sample 5.

[0052] Example 6

[0053] Based on Example 1, the only difference is that 127.8 g Al(NO 3 ) 3 9H 2 O and 1.17gZr(NO 3 )4·5H 2 O was dissolved in deionized water and the volume was adjusted to 680 ml to form salt solution A1; 4.09 g Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water and the volume was adjusted to 130 ml to form salt solution A2; 198.15 g Cu(NO 3 ) 2 ·3H 2 O, 61.00 g Zn(NO 3 ) 2 6H 2 O and 1.93 g Al(NO 3 ) 3 9H 2 O is dissolved in deionized water and the volume is adjusted to 1000 ml to form the salt solution A3 required for precipitation.

[0054] When forming precipitate 1, the preheating temperature of salt solution A1 and alkaline solution B1 is 90°C, the reaction temperature is 90°C, the pH value is 6.8-7.2, and the aging is carried out at 90°C for 4 hours; when forming precipitate 2, the preheating temperature of suspension slurry C is 90°C, the reaction temperature is 90°C, the pH value is 5.8-6.2, and the aging is carried out at 90°C for 2 hours; when forming precipitate 3, the preheating temperature of salt solution A3 is 70°C, the reaction temperature is 80°C, the pH value is 5.8-6.2, and the aging is carried out at 80°C for 2 hours; 2 g of graphite and 15 g of ethanol are added to the obtained filter cake for pulping, and the mixture is dried at 120°C for 3 hours after pulping. N 2 The remaining steps are the same as those in Example 1, and the prepared catalyst is numbered as Sample 6.

[0055] Example 7

[0056] Based on Example 2, the only difference is that 128.83 g Al(NO 3 ) 3 9H 2 O and 1.18gZr(NO 3 )4·5H 2 O was dissolved in deionized water and the volume was adjusted to 680 ml to form salt solution A1; 4.12 g Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water and the volume was adjusted to 130 ml to form salt solution A2; 181.6 g Cu(NO 3 ) 2 ·3H 2 O, 74.54 g Zn(NO 3 ) 2 6H 2 O and 13.64g Al(NO 3 ) 3 9H 2 O is dissolved in deionized water and the volume is adjusted to 1000 ml to form the salt solution A3 required for precipitation.

[0057] When forming precipitate 1, the preheating temperature of salt solution A1 and alkaline solution B1 is 70°C, the reaction temperature is 70°C, the pH value is 6.8-7.2, and the aging is carried out at 70°C for 2 hours; when forming precipitate 2, the preheating temperature of salt solution A2 is 70°C, the reaction temperature is 70°C, the pH value is 6.8-7.2, and the aging is carried out at 70°C for 30 minutes; when forming precipitate 3, the preheating temperature of salt solution A3 is 70°C, the reaction temperature is 70°C, the pH value is 6.8-7.2, and the aging is carried out at 70°C for 1 hour; 2 g of graphite and 20 g of ethanol are added to the obtained filter cake for pulping, and the mixture is dried at 100°C for 5 hours after pulping, and N is introduced during calcination. 2 The remaining steps are the same as those in Example 2, and the prepared catalyst is numbered as Sample 7.

[0058] Example 8

[0059] Based on Example 2, the only difference is that 126.20 g Al(NO 3 ) 3 ·9H2O and 3.67gZr(NO 3 ) 4 ·5H 2 O was dissolved in deionized water and the volume was adjusted to 680 ml to form salt solution A1; 4.11 g Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water and the volume was adjusted to 130 ml to form salt solution A2; 193.07 g Cu(NO3 ) 2 ·3H 2 O, 59.43 g Zn(NO 3 ) 2 6H 2 O and 13.59 g Al(NO 3 ) 3 9H2O is dissolved in deionized water and the volume is adjusted to 1000ml to form the salt solution A3 required for precipitation;

[0060] When forming precipitate 1, the preheating temperature of salt solution A1 and alkaline solution B1 is 80°C, the reaction temperature is 80°C, the pH value is 7.8-8.2, and the aging is carried out at 80°C for 4 hours; when forming precipitate 2, the preheating temperature of salt solution A2 is 80°C, the reaction temperature is 80°C, the pH value is 5.8-6.2, and the aging is carried out at 80°C for 2 hours; when forming precipitate 3, the preheating temperature of salt solution A3 is 80°C, the reaction temperature is 80°C, the pH value is 6.8-7.2, and the aging is carried out at 80°C for 2 hours; 2 g of graphite and 10 g of ethanol are added to the obtained filter cake for pulping, the drying time after pulping is 3 hours, and N is introduced during roasting. 2 The remaining steps are the same as those in Example 2, and the prepared catalyst is numbered as Sample 8.

[0061] Comparative Example 1

[0062] In order to highlight the beneficial effects of the present invention, this comparative example 1 is provided, which adopts the preparation steps substantially the same as those of Example 8, except that the zinc nitrate required for the second step precipitation is added to the salt solution required for the first step precipitation, so that this part of the zinc nitrate is precipitated in the first step, and secondly, graphite and ethanol are not added to the filter cake for pulping. Comparative Example 1 essentially adopts a two-step co-current precipitation method to prepare the catalyst. Comparison of Comparative Example 1 and Example 8 can intuitively reflect the effect of the method of the present invention on the methanol catalyst. The specific preparation method of Comparative Example 1 is as follows:

[0063] 126.20 g Al(NO 3 ) 3 9H 2 O, 3.67 g Zr(NO 3 ) 4 ·5H 2 O and 4.11 g Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water and the volume was adjusted to 680 ml to form salt solution A1; 193.07 g Cu(NO 3 ) 2 ·3H 2 O, 59.43 g Zn(NO 3 ) 26H 2 O and 13.59 g Al(NO 3 ) 3 9H 2 O was dissolved in deionized water and the volume was adjusted to 1000 ml to form the salt solution A2 required for precipitation; 321.18 g NaCO 3 Dissolve in deionized water and adjust the volume to 2500 ml to form the alkaline solution B1 required for precipitation.

[0064] After preheating the salt solution A1 and the alkaline solution B1 to 80°C, the salt solution A1 and the alkaline solution B1 are simultaneously added dropwise into a reaction tank filled with a certain amount of deionized water under strong stirring to form a precipitate 1. The reaction temperature is controlled at 80°C and the pH value is 7.8-8.2. After the addition of solution A1 is completed, the addition of alkali B1 is stopped and constant temperature aging at 80°C is continued for 4 hours.

[0065] After preheating the salt solution A2 to 80°C, the aged precipitate 1, the salt solution A2 and the alkaline solution B1 are simultaneously added dropwise into a reaction tank filled with a certain amount of deionized water under strong stirring to form a precipitate 2. The reaction temperature is controlled at 80°C and the pH value is 6.8-7.2. After the addition of solution A2 and precipitate 1 is completed, the addition of alkali B1 is stopped and the aging is continued at 80°C for 2 hours.

[0066] The aged precipitate 2 was filtered and washed with deionized water until no Na + The filter cake was dried at 120℃ for 3h and then 2 The catalyst was calcined at 500°C for 4 h under a nitrogen atmosphere, and 2 g of graphite was added to the calcined material, stirred, and then molded into a catalyst numbered as comparative sample 1.

[0067] Comparative Example 2

[0068] In order to highlight the beneficial effects of the present invention, this comparative example 2 is provided, which adopts the same preparation steps as comparative example 1, except that the zinc nitrate required for the first step of precipitation is added to the salt solution required for the second step of precipitation, so that this part of the zinc nitrate is precipitated in the second step. Comparative example 2 essentially adopts a two-step parallel flow precipitation method to prepare the catalyst. Comparison of comparative example 2 and embodiment 8 can intuitively reflect the effect of the method of the present invention on the methanol catalyst. The specific preparation method of comparative example 2 is as follows:

[0069] 126.20 g Al(NO 3 ) 3 9H 2 O and 3.67g Zr(NO 3 ) 4 ·5H 2 O 4.11g was dissolved in deionized water and the volume was adjusted to 680ml to form salt solution A1; 193.07g Cu(NO3 ) 2 ·3H 2 O, 63.54gZn(NO 3 ) 2 6H 2 O and 13.59 gAl(NO 3 ) 3 9H 2 O was dissolved in deionized water and the volume was adjusted to 1000 ml to form the salt solution A2 required for precipitation; 321.18 g NaCO 3 Dissolve in deionized water and adjust the volume to 2500 ml to form the alkaline solution B1 required for precipitation.

[0070] The remaining preparation steps and conditions are the same as those of Comparative Example 1.

[0071] Comparative Example 3

[0072] In order to highlight the beneficial effects of the present invention, this comparative example 3 is provided, which adopts the same preparation steps as comparative example 1, except that the zirconium nitrate required for the first step of precipitation is added to the salt solution required for the second step of precipitation, so that this part of the zirconium nitrate is precipitated in the second step. Comparative example 3 essentially adopts a two-step parallel flow precipitation method to prepare the catalyst. Comparison of comparative example 3 and embodiment 8 can intuitively reflect the effect of the method of the present invention on the methanol catalyst. The specific preparation method of comparative example 3 is as follows:

[0073] 126.20 g Al(NO 3 ) 3 9H 2 O and 4.11 g Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water and the volume was adjusted to 680 ml to form salt solution A1; 193.07 g Cu(NO 3 ) 2 ·3H 2 O, 59.43g Zn(NO 3 ) 2 6H 2 O, 3.67g Zr(NO 3 ) 4 ·5H 2 O and 13.59 g Al(NO 3 ) 3 9H 2 O was dissolved in deionized water and the volume was adjusted to 1000 ml to form the salt solution A2 required for precipitation; 321.18 g NaCO 3 Dissolve in deionized water and adjust the volume to 2500 ml to form the alkaline solution B1 required for precipitation.

[0074] The remaining preparation steps and conditions are the same as those of Comparative Example 1.

[0075] Comparative Example 4

[0076] In order to highlight the beneficial effects of the present invention, this comparative example 4 is provided, which adopts the same preparation steps as Example 6, except that the zinc nitrate required for the second step precipitation is added to the salt solution required for the first step precipitation, so that this part of the zinc nitrate is precipitated in the first step, and secondly, graphite and ethanol are not added to the filter cake for pulping. Comparative Example 4 essentially adopts an improved two-step parallel flow precipitation method to prepare the catalyst. Comparison between Comparative Example 4 and Example 6 can intuitively reflect the effect of the method of the present invention on the methanol catalyst. The specific preparation method of Comparative Example 4 is as follows:

[0077] 127.8 g Al(NO 3 ) 3 9H 2 O, 1.17 g Zr(NO 3 )4·5H 2 O and 4.09g Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water and the volume was adjusted to 680 ml to form salt solution A1; 198.15 g Cu(NO 3 ) 2 ·3H 2 O, 61.00 g Zn(NO 3 ) 2 6H 2 O and 1.93 g Al(NO 3 ) 3 9H 2 O was dissolved in deionized water and the volume was adjusted to 1000 ml to form the salt solution A2 required for precipitation; 321.18 g NaCO 3 Dissolve in deionized water and adjust the volume to 2500 ml to form the alkaline solution B1 required for precipitation.

[0078] After preheating the salt solution A1 and the alkaline solution B1 to 90°C, under strong stirring, the salt solution A1 and the alkaline solution B1 are simultaneously added dropwise to a reaction tank filled with a certain amount of deionized water to form a precipitate 1. The reaction temperature is controlled at 90°C and the pH value is 6.8-7.2. After the addition of solution A1 is completed, the addition of alkali B1 is stopped and constant temperature aging at 90°C is continued for 4 hours.

[0079] Filter the aged precipitate 1, add precipitate 1 into the mixed solution A2 to form a highly dispersed suspension slurry C. After preheating the suspension slurry C to 80 °C, under strong stirring, the suspension slurry C and the alkali solution B1 are simultaneously dropped into a reaction tank containing a certain amount of deionized water to form precipitate 2. Control the reaction temperature at 80 °C and the pH value at 5.8 - 6.2. After the dropping of the suspension slurry C is completed, stop dropping the alkali B1 and continue aging at a constant temperature of 80 °C for 2 h.

[0080] Filter the aged precipitate 2 and wash it with deionized water until no Na can be detected + , and the filter cake is dried at 120 °C for 3 h and then calcined at 350 °C for 6 h under N 2 atmosphere. Add 2 g of graphite to the obtained calcined material, stir and then form it into a catalyst, numbered as Comparative Sample 4.

[0081] Comparative Example 5

[0082] To highlight the beneficial effects of the present invention, this Comparative Example 5 is provided. It uses the same preparation steps as Comparative Example 4, except that the zinc nitrate required for the first-step precipitation is added to the salt solution required for the second-step precipitation, and this part of zinc nitrate is precipitated in the second step. Comparative Example 5 essentially uses an improved two-step parallel precipitation method to prepare the catalyst. Comparing Comparative Example 5 and Example 6 can intuitively reflect the effect of the method of the present invention on the methanol catalyst. The specific preparation method of Comparative Example 5 is as follows:

[0083] Dissolve 127.8 g of Al(NO 3 ) 3 ·9H 2 O and 1.17 g of Zr(NO 3 )4·5H 2 O in deionized water and make up the volume to 680 ml to form salt solution A1; dissolve 198.15 g of Cu(NO 3 ) 2 ·3H 2 O, 65.09 g of Zn(NO 3 ) 2 ·6H 2 O and 1.93 g of Al(NO 3 ) 3 ·9H 2 O in deionized water and make up the volume to 1000 ml to form the salt solution A2 required for precipitation; dissolve 321.18 g of NaCO 3 in deionized water and make up the volume to 2500 ml to form the alkali solution B1 required for precipitation.

[0084] The remaining preparation steps and conditions are the same as those in Comparative Example 4.

[0085] Comparative Example 6

[0086] In order to highlight the beneficial effects of the present invention, the present comparative example 6 is provided, which adopts the same preparation steps as comparative example 4, except that the zirconium nitrate required for the first step precipitation is added to the salt solution required for the second step precipitation, so that this part of the zirconium nitrate is precipitated in the second step. Comparative example 6 essentially adopts an improved two-step parallel flow precipitation method to prepare the catalyst. Comparison of comparative example 6 and embodiment 6 can intuitively reflect the effect of the method of the present invention on the methanol catalyst. The specific preparation method of comparative example 6 is as follows:

[0087] 127.8 g Al(NO 3 ) 3 9H 2 O and 4.09g Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water and the volume was adjusted to 680 ml to form salt solution A1; 198.15 g Cu(NO 3 ) 2 ·3H 2 O, 61.00g Zn(NO 3 ) 2 6H 2 O, 1.17 g Zr(NO 3 )4·5H 2 O and 1.93 g Al(NO 3 ) 3 9H 2 O was dissolved in deionized water and the volume was adjusted to 1000 ml to form the salt solution A2 required for precipitation; 321.18 g NaCO 3 Dissolve in deionized water and adjust the volume to 2500 ml to form the alkaline solution B1 required for precipitation.

[0088] Example Catalyst Evaluation Method:

[0089] This example provides an evaluation method for the catalysts of Examples 1-8 and Comparative Examples 1-6, which is as follows:

[0090] Sample particle size: 16-40 mesh. Filling volume: 4 mL (2 mL catalyst + 2 mL inert carrier).

[0091] Sample activation: Samples are activated and heat-resistant using low concentration hydrogen (H 2 / N 2 =3 / 97 (volume ratio)) of hydrogen and nitrogen mixed gas for reduction for 10 to 12 hours, with the highest reduction temperature being 220°C.

[0092] Activity test: The raw gas composition is: CO = 7%, CO 2 =1.2%, N 2=12.5%, the rest is H 2 , reaction pressure is 5.0MPa, space velocity is 10000h -1 , the reaction temperature was 220±2℃, and the CO conversion rate and CH 3 OH space-time yield (the amount of methanol produced per mL of catalyst per hour).

[0093] High temperature selectivity test: After the initial activity is determined, the reaction temperature is raised to 290±2°C and the content of major impurities in the liquid product is determined.

[0094] Heat-resistant activity test: After the high-temperature selectivity is determined, the atmosphere is switched to a reducing atmosphere, the pressure is reduced to 0.1 MPa, the reaction temperature is raised to 450°C, and the air velocity is reduced to 3000 h -1 After heat treatment for 10 hours, the above activity test conditions were restored to measure the CO conversion rate and CH 3 OH space-time yield.

[0095] The above test method was used to evaluate the activity of the catalysts of Examples 1-8 and Comparative Examples 1-6 before and after heat resistance. The results are shown in Table 1. The CH 3 The higher the OH space-time yield, the higher the stability of the catalyst. Taking the impurity content of comparative sample 6 as the benchmark, the impurity content of other samples is divided by the corresponding impurity content of comparative sample 6 multiplied by the benchmark value to obtain the relative value of the impurity content of each sample, thereby intuitively reflecting the high and low impurity content between different samples. The results are shown in Table 2. The catalyst strength test results are shown in Table 3.

[0096] Table 1 Catalyst activity data before and after heat resistance

[0097]

[0098]

[0099] Table 2 High temperature selectivity of catalysts

[0100] Ethanol n-Propanol Isobutanol n-Butanol Sample 1 84 83 82 82 Sample 2 84 82 81 83 Sample 3 84 83 82 83 Sample 4 83 82 83 81 Sample 5 82 81 82 81 Sample 6 92 91 90 91 Sample 7 83 82 84 81 Sample 8 89 88 89 87 Comparative sample 1 92 91 92 90 Comparative sample 2 90 89 90 88 Comparative sample 3 93 92 91 92 Comparative sample 4 96 95 94 93 Comparative sample 5 94 93 92 94 Comparative sample 6 100 100 100 100

[0101] Table 3 Catalyst strength

[0102]

[0103]

[0104] As can be seen from Table 1, the fresh activity and heat-resistant activity of the catalyst sample 8 prepared by the present invention are better than those of the comparative samples 1-3, and the fresh activity and heat-resistant activity of the catalyst sample 6 prepared by the present invention are better than those of the comparative samples 4-6. It can be seen from Table 2 that the present invention not only improves the low-temperature activity and stability of the catalyst, but also improves the high-temperature selectivity; although the active CuO mass fraction in samples 1-5 and sample 7 is lower than that in comparative samples 1-6, it can be seen from Table 1 that the fresh activity of samples 1-5 and sample 7 is not much different, but the heat-resistant activity is better than that of comparative samples 1-6. It can be seen from Table 2 that the present invention improves the selectivity of the catalyst while improving the stability of the catalyst, which shows that the catalyst prepared by the present invention can take into account both activity and stability while also having excellent selectivity. As can be seen from Table 3, the present invention uses graphite beating to improve the strength of the catalyst, especially when adding ethanol during beating, the strength of the catalyst is further improved. It can be seen that when graphite is added in this way, the dispersion of graphite in the catalyst will be more uniform and can better play a role in skeleton support.

[0105] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

[0106] This background section is provided to generally present the context of the invention, and the work of the presently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither explicitly nor implicitly admitted to be prior art to the present invention.

Claims

1. A method for preparing a high-selectivity and high-strength methanol synthesis catalyst, characterized in that The steps include: Step 1: dissolving aluminum nitrate and zirconium nitrate in water to form a salt solution A1; dissolving zinc nitrate in water to form a salt solution A2; dissolving zinc nitrate, copper nitrate and aluminum nitrate in water to form a mixed salt solution A3; dissolving sodium carbonate solution in water to form an alkaline solution B1; Step 2: using the salt solution A1 and the alkaline solution B1 to react in parallel to form a precipitate 1, and then aging the precipitate 1; Step 3: using the aged precipitate 1, salt solution A2 and alkaline solution B1 to react in parallel to form precipitate 2, and controlling the feed rates of precipitate 1 and salt solution A2 so that the precipitate 1 and salt solution A2 react at the same time, and aging the precipitate 2; Step 4: using the aged precipitate 2, the salt solution A3 and the alkaline solution B1 to react in parallel to form the precipitate 3, and controlling the feed rates of the precipitate 2 and the salt solution A3 so that the precipitate 2 and the salt solution A3 are completed at the same time, and the precipitate 3 is aged; Step 5: The aged precipitate 3 is washed and filtered, and graphite is added to the obtained filter cake for slurrying, and then dried, calcined and formed to obtain a methanol synthesis catalyst.

2. The method for preparing a high-selectivity and high-strength methanol synthesis catalyst according to claim 1, characterized in that: In the obtained methanol synthesis catalyst, the content of CuO is 56.4-64.6%, the content of ZnO is 17.1-25.4%, the content of Al2O3 is 16.3-19.8%, the content of ZrO2 is 0.3%-1.1%, and the total mass percentage is 100%.

3. The method for preparing a high-selectivity and high-strength methanol synthesis catalyst according to claim 1, characterized in that: The obtained methanol synthesis catalyst also contains graphite, and the graphite accounts for 1 to 3% of the total mass of the catalyst.

4. The method for preparing a high-selectivity and high-strength methanol synthesis catalyst according to claim 1, characterized in that: In step 1, in salt solution A1, the molar amount of zirconium accounts for 0.8% to 2.5% of the total molar amount of aluminum and zirconium; in salt solution A2, the molar concentration of zinc is 0.1 to 0.5 mol / L; in salt solution A3, Al 3+ The molar amount of Cu 2+ 、Zn 2+ and Al 3+ 0.5%~3.5% of the total molar amount, Cu 2+ and Zn 2+ The molar ratio is 3 to 4:

1.

5. The method for preparing a high-selectivity and high-strength methanol synthesis catalyst according to claim 1, characterized in that: In step 2, the parallel flow reaction temperature is controlled to be 60-90° C. and the pH value is 7-9; the aging temperature of the precipitate 1 is 60-90° C. and the time is 2-4 hours.

6. The method for preparing a high-selectivity and high-strength methanol synthesis catalyst according to claim 1, characterized in that: In step 3, the parallel flow reaction temperature is controlled to be 60-90° C., and the pH value is 6-8; the aging temperature of the precipitate 2 is 60-90° C., and the aging time is 1-2 h.

7. The method for preparing a high-selectivity and high-strength methanol synthesis catalyst according to claim 1, characterized in that: In step 4, the parallel flow reaction temperature is controlled to be 60-80° C. and the pH value is 6-8; the aging temperature of the precipitate 3 is 60-80° C. and the time is 1 h to 2 h.

8. The method for preparing a high-selectivity and high-strength methanol synthesis catalyst according to claim 1, characterized in that: In step 5, ethanol is added together with graphite for slurrying, and the amount of ethanol added accounts for 10% to 20% of the total mass of the catalyst; the drying temperature is 100 to 120°C, and the time is 3h to 5h; N2 is introduced during calcination, the calcination temperature is 350°C to 500°C, and the calcination time is 4 to 6h.

9. A high-selectivity and high-strength methanol synthesis catalyst prepared according to the method of any one of claims 1 to 8.

10. Use of the catalyst according to claim 9 in methanol synthesis.

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