Catalyst precursor washing method and catalyst preparation method

Abstract

According to the washing method of the catalyst precursor and the preparation method of the catalyst, the solid-liquid mixture containing the catalyst precursor is treated through the method, efficient washing of the catalyst precursor can be achieved under the condition of low washing liquid consumption, and the stability of the catalyst precursor can be improved. The washing method comprises the following steps: (1) diluting a solid-liquid mixture containing a catalyst precursor, which is obtained in a process of preparing a catalyst by a precipitation method or an electrolytic method, by using a first washing liquid at the temperature of 40-60 DEG C to obtain a diluted feed liquid; the pH value of the first washing liquid is 6.5-8.5, and the dosage of the first washing liquid is 10-60% of the volume of the solid-liquid mixture; and (2) filtering the diluted feed liquid, and washing the filtered solid part by using a second washing liquid with the temperature of 40-70 DEG C, wherein the pH value of the second washing liquid is 6.5-8.0.

Description

Technical Field

[0001] The invention relates to the technical field of catalyst preparation requiring solid-liquid separation, and in particular to a catalyst precursor washing method and a catalyst preparation method. Background Art

[0002] In the process of preparing the catalyst by coprecipitation or electrolysis, insoluble matter or crystals (i.e., catalyst precursor) are formed in the mother liquor, and solid-liquid separation and washing are required to make the catalyst precursor free of impurity ions in the mother liquor. The catalyst washing process is a key process that restricts the production efficiency of the catalyst. If the washing is not sufficient, the residual ions will become impurities in the target catalyst, which will reduce the selectivity of the target product in the downstream chemical catalytic reaction process and even affect the service life of the catalyst.

[0003] Patent application CN102897962A discloses a zero-discharge water recycling process for the co-precipitation production of copper-based catalysts. The sodium nitrate aqueous solution produced after precipitation and the sodium nitrate aqueous solution obtained by washing the filter cake are treated by reverse osmosis, and the treated water is used in the production line after reaching the reuse standard. The concentrated sodium nitrate is evaporated by multiple effects to obtain the sodium nitrate product. This technical method is only suitable for treating wastewater containing sodium nitrate, and multi-stage water reuse cannot reduce the number of washing times and the floor space occupied by intermediate storage tanks and containers during the washing process.

[0004] Patent application CN102897962 A discloses a zero-discharge water recycling process for the co-precipitation production of copper-based catalysts. The key core of the invention is that nitrate and sodium carbonate are used as co-precipitation raw materials in the co-precipitation catalyst. The main component of the mother liquor after precipitation is sodium nitrate. Through the washing water circulation process, the wastewater containing high-concentration sodium nitrate is recovered by evaporation and crystallization, and the distilled water is reused to the production line. This method is only applicable to specific co-precipitation processes, and if the precipitate is fully washed, multiple pulping is required, and a large amount of equipment and manpower are required to support the process route.

[0005] Patent CN203291873U designs a catalyst washing device for preparation by precipitation method. The device is only suitable for washing with water, and the method is to wash repeatedly with a plate and frame filter press and then enter a belt filter. This method squeezes the filter cake at the initial stage of high-concentration mother liquor washing, which is not conducive to washing the residual liquid in the precursor gap, and multiple pulping is required to achieve the cleaning purpose.

[0006] Patent CN218309688U designs a continuous washing machine for hydrogenation catalysts, the purpose of which is to repeatedly wash the catalysts. However, it is difficult to achieve the washing requirements of low impurity concentrations through this machine, especially for catalyst precursors that are easy to form gels during precipitation and are difficult to separate solids from liquids.

[0007] The method disclosed in patent CN 103721706 B is a reduction washing method for catalysts, which is suitable for catalysts that require pre-reduction, but not suitable for oxide catalysts or catalysts that require a multi-step production process. The disclosed method uses an additional gas to achieve full contact between the washing liquid and the mother liquor to be washed. If this method uses a non-reducing atmosphere, the investment is relatively large, especially for non-precious metal catalysts. The method is not suitable for catalysts that require a large amount of washing liquid to wash until the precursor impurity content is low, and the method has great limitations. Summary of the invention

[0008] The present invention provides a method for washing a catalyst precursor and a method for preparing a catalyst. By treating a solid-liquid mixture containing a catalyst precursor obtained in a catalyst preparation process by a precipitation method or an electrolysis method, the method of the present invention can achieve efficient washing of the catalyst precursor at a lower washing liquid consumption, and is conducive to improving the stability of the catalyst precursor, thereby improving the performance of the final catalyst.

[0009] To achieve the purpose, the present invention provides the following technical solutions:

[0010] In one aspect, the present invention provides a method for washing a catalyst precursor, comprising the following steps:

[0011] (1) diluting a solid-liquid mixture containing a catalyst precursor obtained in a catalyst preparation process by a precipitation method or an electrolysis method with a first washing liquid having a temperature of 40-60° C. to obtain a diluted feed liquid; the pH of the first washing liquid is 6.5-8.5, and the amount of the first washing liquid is 10-60% of the volume of the solid-liquid mixture;

[0012] (2) Filter the diluted feed solution and wash the filtered solid portion with a second washing solution having a temperature of 40-70° C., wherein the pH of the second washing solution is 6.5-8.0.

[0013] The washing method provided by the present invention is suitable for catalyst production application scenarios that require solid-liquid separation and require the use of inorganic and / or organic substances as washing liquids to wash catalyst precursors. Specifically, in the process of preparing catalysts by precipitation or electrolysis, target insoluble substances or crystals (i.e., catalyst precursors) will be formed in the mother liquor. It is necessary to separate the catalyst precursor from the mother liquor and avoid the ions in the mother liquor (i.e., ions brought by the mother liquor components) being entrained in the catalyst precursor as much as possible. The solid-liquid mixture containing the catalyst precursor in the above-mentioned application scenario is treated by the washing method of the present invention, and the separation of the catalyst precursor and the removal of impurities can be achieved with simple operating procedures and less washing liquid consumption. In addition, the separation and washing of the catalyst precursor based on the washing process of the present invention can improve the performance of the final catalyst, for example, it can improve the initial activity and performance stability of the final catalyst, and improve the service life of the catalyst. The inventors have found that the solid-liquid mixture containing the catalyst precursor (i.e., the mixture of the catalyst precursor and the mother liquor) is first diluted with a first washing liquid of pH 6.5-8.5 at 40-60°C in a volume dosage of 10-60%, and then the subsequent filtering and washing operations are performed, which can significantly improve the washing effect; the solid-liquid mixture is diluted in advance with the above-mentioned specific first washing liquid according to the above-mentioned proportion, which is conducive to forming a more uniform microscopic concentration difference, so that the impurity ions entrained in the surface of the catalyst precursor and the microscopic pore structure are more easily dissolved in the washing liquid during the dilution process and the subsequent filtering / washing process, achieving a better washing effect, and helping to reduce the total washing liquid consumption. At the same time, after dilution, the second washing liquid of pH 6.5-8.0 at 40-70°C is used for flushing and filtration, which is conducive to the efficient dissolution of impurity ions in the catalyst precursor.

[0014] In the catalyst preparation process, irregular microstructures may be formed, and these microstructures may have certain regular channels or irregular channels, and these channels are easy to form local confined structures during the washing process, and the ions in the mother liquor are easily residual in the structure. By the dilution, filtering and rinsing operations in the steps (1) and (2) of the present invention, and the use of a specific first washing liquid and a second washing liquid, it is not only beneficial to the separation of the catalyst precursor and the washing and removal of surface impurities, but also beneficial to fully dissolve the impurity ions that may be entrained in the catalyst precursor microstructure, and can more thoroughly wash off the mother liquor remaining in the solid surface and the secondary particle accumulation channel. By the washing process of the present invention, it is not only possible to more fully and thoroughly dissolve the impurities entrained in the catalyst precursor, and it is also beneficial to ensure the quality of the final catalyst obtained, such as being beneficial to improving the initial activity, thermal stability and service life of the catalyst.

[0015] In some embodiments, the temperature of the first washing liquid is 40°C, 42°C, 45°C, 50°C, 52°C, 55°C, 57°C or 60°C, etc., and the pH value is 6.5, 6.7, 6.9, 7.1, 7.5, 7.8, 8.0, 8.3 or 8.5, etc., and the amount of the first washing liquid is 10%, 20%, 30%, 40%, 50% or 60% of the volume of the solid-liquid mixture; in some embodiments, the temperature of the second washing liquid is 40°C, 42°C, 45°C, 50°C, 52°C, 55°C, 57°C, 60°C, 65°C or 70°C, etc., and the pH value is 6.5, 6.7, 6.9, 7.1, 7.5, 7.8 or 8.0, etc.

[0016] Preferably, in step (2), the temperature of the second washing liquid is 40-60°C, more preferably 45-60°C; using the second washing liquid at the preferred temperature for flushing and filtering in step (2) is conducive to more thoroughly washing away the impurity ions contained in the layered structure of the catalyst precursor.

[0017] Preferably, in step (2), the pH of the second washing solution is 7-8; using the second washing solution with a preferred pH of 7-8 for washing and filtering in step (2) is conducive to more thoroughly washing away the weakly alkaline impurity ions in the catalyst precursor.

[0018] In some preferred embodiments, in step (2), a second washing solution having a temperature of 40-60° C. and a pH of 7-8 is used for washing.

[0019] In the present invention, the first washing liquid and the second washing liquid can be inorganic and / or organic washing liquids that are inert to the reaction of the catalyst precursor. In some embodiments, the first washing liquid or the second washing liquid is one or more of water and an organic solvent, and the organic solvent is, for example, one or more of methanol, ethanol, propane, isopropanol, tetrahydrofuran, ether, ethyl acetate, and petroleum ether. The first washing liquid or the second washing liquid optionally contains less than 1.0wt% of a mother liquor component, for example, 0.01-1.0wt%, and the mother liquor component is, for example, a nitrate, and the nitrate is, for example, selected from one or more of potassium nitrate, sodium nitrate, and ammonium nitrate; the first washing liquid or the second washing liquid can be a washing liquid recycled from the washing process, and the recycled washing liquid as the first or second washing liquid preferably needs to satisfy the content of the mother liquor component below 1.0wt%, for example, 0.01-1.0wt%.

[0020] Preferably, step (2) is carried out in a device capable of filtering and flushing at the same time, and preferably the device is a suction conveyor belt filter.

[0021] In some embodiments, in step (2), the amount of the second washing liquid used is, for example, 2-10 times the volume of the solid-liquid mixture in step (1), for example, 2, 3, 5, 8 or 10 times.

[0022] In some embodiments, in step (2), the rinsing is performed until the content of the target impurity in the obtained filtrate is less than 95% of the initial content of the target impurity. The initial content of the target impurity refers to the mass content of the target impurity in the liquid portion (i.e., mother liquor) obtained by sampling the solid-liquid mixture containing the catalyst precursor before the dilution operation in step (1) and separating the liquid portion, i.e., mother liquor, as the initial content.

[0023] In some embodiments, step (3) is further included: the solid portion obtained in step (2) is further stirred, washed and filtered with a third washing liquid, and the amount of the third washing liquid is preferably 2-5 times the mass of the solid portion, for example, 2, 3, 4 or 5 times. Preferably, step (3) is performed once or more until the content of the target impurity meets the preset requirements, for example, the content of the target impurity is lower than 1% or lower. When the preset requirements for the content of the target impurity are high, step (3) can be performed, and step (3) can be performed once or more according to different requirements for the specific target impurity content. In some examples, after performing steps (1) and (2), the preset requirements for the target impurity content can be met, and there is no need to continue step (3). The target impurities are, for example, ions brought in by the solvent used in the preparation of the catalyst, such as ions brought by the mother liquor component.

[0024] In some embodiments, the third washing liquid is one or more of water and an organic solvent, and the organic solvent is preferably one or more of methanol, ethanol, propane, isopropanol, tetrahydrofuran, ether, ethyl acetate, and petroleum ether. The third washing liquid optionally contains ≤0.05wt% of a mother liquor component, and may also be pure water and / or a pure organic solvent, wherein the mother liquor component is, for example, a nitrate, and the nitrate is, for example, selected from one or more of potassium nitrate, sodium nitrate, and ammonium nitrate%; in some embodiments, the third washing liquid is the same as the second washing liquid, for example, the second washing liquid satisfying the content of the mother liquor component ≤0.05wt% is used as the third washing liquid. The third washing liquid can be a washing liquid recycled from the washing process, and the recycled washing liquid as the third washing liquid preferably needs to satisfy the content of the mother liquor component ≤0.05wt%.

[0025] By using the washing method of the present invention, under the same target impurity washing requirements, compared with the traditional washing method, efficient washing can be achieved with relatively less washing liquid consumption and simpler operation. Moreover, the washing method of the present invention is conducive to improving the stability of the catalyst precursor, improving the performance of the final catalyst, and extending the life of the catalyst while achieving a fast, energy-saving and efficient washing effect.

[0026] Furthermore, the precipitation method is, for example, single-component precipitation, multi-component co-precipitation, uniform precipitation or immersion precipitation;

[0027] The catalyst precursor may be an organic substance, an inorganic substance, or a mixture of an organic substance and an inorganic substance. When it is a mixture of an organic substance and an inorganic substance, the two substances are preferably miscible.

[0028] Preferably, when the solid-liquid mixture containing the catalyst precursor is prepared by the precipitation method or electrolysis method, the solvent used is an aqueous solution with a pH of 6.5-8.5, and 0.05-1wt% of a mother liquor component is added to the aqueous solution, and the mother liquor component is, for example, a nitrate, and the nitrate is, for example, selected from one or more of potassium nitrate, sodium nitrate, and ammonium nitrate. Specifically, in the process of preparing the catalyst by precipitation or electrolysis, the above-mentioned solvent is used to prepare the solution required for preparing the catalyst by precipitation or electrolysis. The washing method of the present invention is particularly suitable for washing the solid-liquid mixture containing the catalyst precursor obtained in the process of preparing the catalyst by precipitation or electrolysis based on such a solvent system.

[0029] The washing liquid containing a small amount of mother liquor can be reused for washing to achieve full utilization of washing liquid resources, such as impurities (such as NaNO in some examples). 3 ) content is below 1wt%, for example, the washing liquid with the above impurity content of 0.01-1.0wt%, for example, the washing liquid with the above impurity content of 0.05-1wt% can be recycled for further use. After removing more than 99% of the mother liquor components, the washing liquid can be separated and recovered and reused as the solvent required for the preparation of the catalyst precursor, realizing the multi-effect recycling of the solvent and achieving the purpose of energy saving and consumption reduction.

[0030] In some embodiments, a soluble salt containing a metal element is prepared by a precipitation method or an electrolysis method to obtain the solid-liquid mixture containing the catalyst precursor;

[0031] The metal elements include, for example, one or more of copper, zinc, aluminum, magnesium, zirconium, manganese, lanthanum, cerium, nickel, titanium, platinum, palladium, rhodium, and ruthenium; the soluble salts include, for example, nitrates and the like.

[0032] The present invention also provides a method for preparing a catalyst, wherein a solid-liquid mixture containing a catalyst precursor is prepared by a precipitation method or an electrolysis method, the solid-liquid mixture is washed to obtain a washed catalyst precursor, and then dried and calcined, wherein the washing is performed by the washing method described above. In some embodiments, a molding operation is also included after calcination.

[0033] The main improvement of the present invention over the prior art is that a washing scheme is proposed for the solid-liquid mixture containing the catalyst precursor that needs to be separated and washed and is formed in the process of preparing the catalyst by precipitation or electrolysis. For the other processes in the preparation of the catalyst by precipitation or electrolysis except the washing process (such as precipitation or electrolysis process, drying process, calcination process and molding process, etc.), they can be carried out with reference to the corresponding processes in the art, but the key is to use the washing steps of the present invention to separate and wash the solid-liquid mixture containing the catalyst precursor.

[0034] Specifically, in some embodiments, a solvent is first used to prepare various solutions required for preparing a catalyst by precipitation or electrolysis. For example, in preparing a catalyst in which metal elements such as copper, zinc and / or aluminum are active metal elements by precipitation or electrolysis, the aforementioned solvent is first used to prepare a solution of a soluble salt (such as nitrate, etc.) of each corresponding active metal element, and then the prepared solutions are subjected to precipitation or electrolysis to obtain a solid-liquid mixture containing a catalyst precursor after precipitation (or crystallization or electrolysis), wherein the solvent is preferably an aqueous solution with a pH of 6.5-8.5, to which 0.05-1wt% of a mother liquor component is added, and the mother liquor component is, for example, a nitrate, and the nitrate is, for example, selected from one or more of potassium nitrate, sodium nitrate, and ammonium nitrate. Then, the solid-liquid mixture containing the catalyst precursor is washed according to the aforementioned washing method. Specifically, first, according to step (1) of the aforementioned washing method, the mixture is diluted with a first washing liquid having a temperature of 40-60°C and a pH of 6.5-8.5 at a volume of 10-60%, and stirred evenly; then, according to step (2) of the aforementioned washing method, the mixture is filtered and rinsed with a second washing liquid having a temperature of 40-70°C and a pH of 6.5-8.0, for example, the mixture is uniformly passed through a suction conveyor filter with separation capability at a certain flow rate, and the mother liquid remaining on the solid surface and in the secondary particle accumulation channel is rinsed at the same time. Optionally, step (3) of the aforementioned washing method can also be performed, for example, the mixture is sent into a container with stirring and fully stirred in a third washing liquid, and then the solid-liquid mixture is separated by a pressurized filtration device. The contents of the washing method can all be referred to the above description, and will not be repeated here.

[0035] In some embodiments, the catalyst is a catalyst prepared by coprecipitation of a solution containing copper nitrate, zinc nitrate, and aluminum nitrate with a sodium carbonate solution, wherein the molar ratio of copper nitrate, zinc nitrate, aluminum nitrate, and sodium carbonate is, for example, (0.5-1):(0.3-1):(0.1-0.5):(1-3). After precipitation reaction and aging, a solid-liquid mixture containing basic copper zinc carbonate is obtained, and the solid-liquid mixture is washed by the washing method of the present invention. The obtained catalyst precursor can be dried, roasted, and other processes to obtain a catalyst with excellent performance. The catalyst can be used as a catalyst for preparing methanol from synthesis gas.

[0036] The technical solution provided by the present invention has the following beneficial effects:

[0037] The present invention provides a washing method which has the characteristics of low washing cost and low equipment investment, and can also obtain better washing effect and ensure the quality of terminal products.

[0038] The washing method of the present invention has wide applicability to application scenarios involving solid-liquid separation and washing processes of catalyst precursors in precipitation methods or electrolysis methods, and is a multi-purpose catalyst washing method. DETAILED DESCRIPTION

[0039] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with examples. It should be understood that the following examples are only for a better understanding of the present invention and do not mean that the present invention is limited to the following examples.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The term "and / or" as may be used herein includes any and all combinations of one or more of the related listed items. The terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

[0041] The present invention is described below by taking the preparation of a catalyst for producing methanol from synthesis gas as an example, but it should not be understood that the present invention is limited thereto.

[0042] In the following examples and comparative examples, a mixture containing 0.05-1 wt% NaNO 3 An aqueous solution with a pH value of 6.5-8.5 is used as a solvent, and raw materials required for co-precipitation such as copper nitrate, zinc nitrate, and aluminum nitrate are configured. Under the conditions of a precipitation temperature of 60-75°C, an aging temperature of 75-80°C, and an aging time of 0.5-18h, a solid-liquid mixture containing basic copper zinc carbonate, aluminum hydroxide, and an aqueous sodium nitrate solution is prepared by a co-precipitation method. An example of separation of the solid-liquid mixture is taken, wherein the solid content in the solid-liquid mixture ranges from 20 to 60wt%, and the washing target is to wash until the content of impurity Na element (target impurity) in the catalyst precursor product obtained after drying is less than 600ppm, and more preferably less than 500ppm.

[0043] In the following examples and comparative examples, the content of target impurities in the catalyst precursor was detected by I CP elemental analysis.

[0044] In the following embodiments, in step (2), the initial value of the target impurity refers to sampling the solid-liquid mixture to be washed and separating the liquid portion (i.e., mother liquor) therefrom, and the mass content of the target impurity ions in the liquid portion is the initial value.

[0045] Example 1

[0046] Using 0.05wt% NaNO 3 Using water with a pH of 6.5 as a solvent, a mixed solution containing 1 mol / L of copper nitrate, zinc nitrate and aluminum nitrate (wherein the molar fraction of copper, zinc and aluminum is 0.6:0.3:0.1) is prepared, and the solution is mixed with 1 mol / L of sodium carbonate solution (prepared with the above solvent) at a volume ratio of 1:1 at 68°C for precipitation reaction for 5 hours, and aged at 75°C for 2 hours to obtain a solid-liquid mixture containing 20% ​​by mass of solids. The washing steps are as follows:

[0047] (1) First, add 50% volume of the first washing liquid (the washing liquid is 0.05 wt% NaNO) at a temperature of 50°C and a pH of 6.5 to the solid-liquid mixture to be washed. 3 Aqueous solution) is diluted and stirred evenly to obtain a diluted feed solution;

[0048] (2) The diluted liquid was then uniformly passed through a suction conveyor filter with separation capability at a certain flow rate (2500 L / h), and was simultaneously rinsed with a second washing liquid to wash away the mother liquid remaining on the solid surface and in the secondary particle accumulation pores. The second washing liquid was 0.05 wt% NaNO at a temperature of 60°C and a pH of 6.5. 3 aqueous solution; step (2) washing until the content of the target impurity in the filtrate finally filtered out is less than 96% of the initial value;

[0049] (3) recovering the solid, sending it into a stirring container, adding pure water (i.e., the third washing liquid) twice the mass of the solid, stirring it thoroughly, and then separating the solid-liquid mixture through a pressure filtration device to obtain a catalyst precursor. After drying the catalyst precursor (drying conditions are 120° C., 10 h), it is detected that the content of the target impurity in the catalyst precursor is less than 400 ppm;

[0050] The catalyst precursor was crushed, calcined (calcination conditions were 330 °C, 5 h) and formed, and then used for catalyst activity test. 2 , where the hydrogen-carbon molar ratio is controlled within the range of 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate was 80%. After being heated at 400°C for 5 hours and then cooled to 230°C, the CO conversion rate was 65% and the activity retention rate was 81%.

[0051] In this embodiment, the total amount of washing liquid consumed in the above washing steps is 5 times the volume of the solid-liquid mixture to be washed.

[0052] Example 2

[0053] Using 0.1wt% NaNO 3 Using water with a pH of 7.1 as a solvent, a mixed solution containing 1.5 mol / L of copper nitrate, zinc nitrate and aluminum nitrate (wherein the molar fraction of copper, zinc and aluminum is 0.6:0.3:0.1) is prepared, and the solution is mixed with 1.5 mol / L of sodium carbonate solution (prepared with the above solvent) at a volume ratio of 0.9:1 at 72°C for precipitation reaction for 4 hours, and aged at 78°C for 1 hour to obtain a solid-liquid mixture containing 40% by mass of solids. The washing steps are as follows:

[0054] (1) First, add 40% volume of the first washing liquid (0.1 wt% NaNO 3 Aqueous solution) is diluted and stirred evenly to obtain a diluted feed solution;

[0055] (2) The diluted liquid was then uniformly passed through a suction conveyor filter with separation capability at a certain flow rate (2000 L / h), and was simultaneously rinsed with a second washing liquid to wash away the mother liquid remaining on the solid surface and in the secondary particle accumulation pores. The second washing liquid was 0.05 wt% NaNO at a temperature of 55 °C and a pH of 7.1. 3 aqueous solution; step (2) washing until the content of the target impurity in the filtrate finally filtered out is less than 96% of the initial value;

[0056] (3) recovering the solid, sending it into a stirring container, adding a second washing liquid three times the mass of the solid to fully stir, and then separating the solid-liquid mixture by a pressure filtration device to obtain a catalyst precursor. After drying the catalyst precursor (drying conditions are 120° C., 10 h), it is detected that the content of the target impurity in the catalyst precursor is less than 500 ppm;

[0057] The catalyst precursor was crushed, calcined (calcination condition was 330℃, 5h) and formed, and then used for catalyst activity test. 2 , where the hydrogen-carbon molar ratio is controlled within the range of 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate was 76%. After being heated at 400°C for 5 hours and then cooled to 230°C, the CO conversion rate was 58% and the activity retention rate was 76%.

[0058] In this embodiment, the total amount of washing liquid consumed in the above washing steps is 6 times the volume of the solid-liquid mixture to be washed.

[0059] Example 3

[0060] Using 0.5wt% NaNO 3Using water with a pH of 7.5 as a solvent, a mixed solution containing 0.5 mol / L of copper nitrate, zinc nitrate and aluminum nitrate (wherein the molar fraction of copper, zinc and aluminum is 0.6:0.3:0.1) is prepared, and the solution is mixed with 0.5 mol / L of sodium carbonate solution (prepared with the above solvent) at a volume ratio of 1:1.2 at 73°C for precipitation reaction for 4 hours, and aged at 78°C for 2 hours to obtain a solid-liquid mixture containing 30% by mass of solids. The washing steps are as follows:

[0061] (1) First, add 60% volume of the first washing liquid (the washing liquid is 0.1wt% NaNO 3 Aqueous solution) is diluted and stirred evenly to obtain a diluted feed solution;

[0062] (2) The diluted liquid was then uniformly passed through a suction conveyor filter with separation capability at a certain flow rate (1500 L / h), and was simultaneously rinsed with a second washing liquid to wash away the mother liquid remaining on the solid surface and in the secondary particle accumulation pores. The second washing liquid was 0.01 wt% NaNO at a temperature of 50°C and a pH of 6.5. 3 aqueous solution; step (2) washing until the content of the target impurity in the filtrate finally filtered out is less than 96% of the initial value;

[0063] (3) recovering the solid, sending it into a stirring container, adding a second washing liquid 4 times the mass of the solid and stirring it thoroughly, and then separating the solid-liquid mixture through a pressure filtration device to obtain a catalyst precursor. After drying the catalyst precursor (drying conditions are 120° C., 10 h), it is detected that the content of the target impurity in the catalyst precursor is less than 550 ppm;

[0064] The catalyst precursor was crushed, calcined (calcination condition was 330℃, 5h) and formed, and then used for catalyst activity test. 2 , where the hydrogen-carbon molar ratio is controlled within the range of 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate was 72%. After being heated at 400°C for 5 hours and then cooled to 230°C, the CO conversion rate was 54% and the activity retention rate was 75%.

[0065] In this embodiment, the total amount of washing liquid consumed in the above washing steps is 7 times the volume of the solid-liquid mixture to be washed.

[0066] Example 4

[0067] Using 1.0wt% NaNO 3Using water with a pH of 8.5 as a solvent, a mixed solution containing 0.8 mol / L of copper nitrate, zinc nitrate and aluminum nitrate (wherein the molar fraction of copper, zinc and aluminum is 0.6:0.3:0.1) is prepared, and the solution is mixed with 0.8 mol / L of sodium carbonate solution (prepared with the above solvent) at a volume ratio of 1:1.1 at 72°C for precipitation reaction for 4 hours, and aged at 78°C for 1 hour to obtain a solid-liquid mixture containing 60% by mass of solids. The washing steps are as follows:

[0068] (1) First, add 20% volume of the first washing liquid (the washing liquid is 1.0 wt% NaNO) at a temperature of 40°C and a pH of 8.5 to the solid-liquid mixture to be washed. 3 Aqueous solution) is diluted and stirred evenly to obtain a diluted feed solution;

[0069] (2) The diluted liquid was then uniformly passed through a suction conveyor filter with separation capability at a certain flow rate (1000 L / h), and was simultaneously rinsed with a second washing liquid to wash away the mother liquid remaining on the solid surface and in the secondary particle accumulation pores. The second washing liquid was 0.05 wt% NaNO at a temperature of 45 °C and a pH of 6.5. 3 aqueous solution; step (2) washing until the content of the target impurity in the filtrate finally filtered out is less than 95% of the initial value;

[0070] (3) recovering the solid, sending it into a stirring container, adding a second washing liquid 5 times the mass of the solid and stirring it thoroughly, and then separating the solid-liquid mixture through a pressure filtration device to obtain a catalyst precursor. After drying the catalyst precursor (drying conditions are 120° C., 10 h), it is detected that the content of the target impurity in the catalyst precursor is less than 600 ppm;

[0071] The catalyst precursor was crushed, calcined (calcination condition was 330℃, 5h) and formed, and then used for catalyst activity test. 2 , where the hydrogen-carbon molar ratio is controlled within the range of 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate was 67%. After heating at 400°C for 5 hours and then cooling to 230°C, the CO conversion rate was 50% and the activity retention rate was 74%.

[0072] In this embodiment, the total amount of washing liquid consumed in the above washing steps is 8 times the volume of the solid-liquid mixture to be washed.

[0073] Comparative Example 1

[0074] The washing steps of this comparative example are as follows:

[0075] First, the solid-liquid mixture to be washed was separated in a pressure filter to remove the mother liquor, and the separated solid was sent to a container with stirring, and a washing liquid with a temperature of 30°C and a pH of 6.5 (the washing liquid was 0.05wt% NaNO 3 The solid-liquid mixture is separated by a pressure filtration device to complete a washing cycle, and then the washing cycle is repeated for multiple times, with a total water consumption of about 10.5 times the volume of the solid-liquid mixture to be washed.

[0076] The solid separated after the last beating was dried (drying conditions were 120 ° C, 10 h), and the content of the target impurity was measured to be less than 600 ppm. After crushing, roasting (roasting conditions were 330 ° C, 5 h) and molding, it was used for catalyst activity test. 2 , where the hydrogen-carbon molar ratio is 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate was 63%. After being heated at 400°C for 5 hours and then cooled to 230°C, the CO conversion rate was 44% and the activity retention rate was 70%.

[0077] Comparative Example 2

[0078] The method is carried out in accordance with Example 1, except that step (1) in Example 1 is not performed during washing. However, more washing liquid is required to achieve the same washing effect, and the activity and stability are affected.

[0079] The washing steps are as follows:

[0080] (1) The solid-liquid mixture to be washed is uniformly passed through a suction conveyor filter with separation capability at a certain flow rate (2500 L / h), and is simultaneously rinsed with a second washing liquid to wash away the mother liquid remaining on the solid surface and in the secondary particle accumulation pores. The second washing liquid is 0.05 wt% NaNO at a temperature of 60°C and a pH of 6.5. 3 aqueous solution; step (1) washing until the content of the target impurity in the final filtrate is less than 96% of the initial value;

[0081] (2) recovering the solid, sending it into a stirring container, adding pure water twice the mass of the solid to fully stir it, and then separating the solid-liquid mixture through a pressure filtration device; repeating the above-mentioned washing operation twice, and then obtaining a catalyst precursor, drying the catalyst precursor (drying conditions are 120° C., 10 h), and detecting that the content of the target impurity in the catalyst precursor is less than 400 ppm;

[0082] The catalyst precursor was crushed, calcined (calcination conditions were 330 °C, 5 h) and formed, and then used for catalyst activity test.2 , where the hydrogen-carbon molar ratio is controlled within the range of 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate was 78%. After being heated at 400°C for 5 hours and then cooled to 230°C, the CO conversion rate was 61% and the activity retention rate was 78%.

[0083] The total amount of washing liquid consumed in the washing step of this comparative example is about 9 times the volume of the solid-liquid mixture to be washed. Compared with Example 1, this comparative example does not perform the dilution step in Example 1 under the condition that other conditions are basically the same. As a result, the washing liquid consumption of this comparative example is significantly increased, and the washing in step (2) needs to be repeated multiple times to achieve the same target impurity content level. In addition, compared with Example 1, the initial activity and stability of the catalyst finally obtained in this comparative example are also significantly reduced.

[0084] Comparative Example 3 (In step (1), the temperature of the first washing liquid is 30° C.)

[0085] The method is carried out in accordance with Example 1, except that the temperature of the first washing liquid used in step (1) of the washing process is 30° C. Steps (2) and (3) are carried out as follows:

[0086] Step (2): The diluted feed liquid is uniformly passed through a suction conveyor filter with separation capability at a certain flow rate (2500 L / h), and is simultaneously rinsed with a second washing liquid to wash away the mother liquid remaining on the solid surface and in the secondary particle accumulation pores. The second washing liquid is 0.05 wt% NaNO at a temperature of 60°C and a pH of 6.5. 3 aqueous solution; step (2) washing until the content of the target impurity in the final filtrate is less than 96% of the initial value;

[0087] Step (3): recover the solid, send it into a stirring container, add pure water twice the mass of the solid and stir it thoroughly, and then separate the solid-liquid mixture through a pressure filtration device; the above washing operation needs to be repeated once, and then a catalyst precursor is obtained. After the catalyst precursor is dried (drying conditions are 120° C., 10 hours), the content of the target impurity in the catalyst precursor is detected to be less than 400 ppm;

[0088] The catalyst precursor was crushed, calcined (calcination conditions were 330 °C, 5 h) and formed, and then used for catalyst activity test. 2 , where the hydrogen-carbon molar ratio is controlled within the range of 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate was 76%. After being heated at 400°C for 5 hours and then cooled to 230°C, the CO conversion rate was 60% and the activity retention rate was 79%.

[0089] The total amount of washing liquid consumed in the above-mentioned washing step in this embodiment is about 7 times the volume of the solid-liquid mixture to be washed. Compared with Example 1, under the condition that other conditions are basically the same, the total amount of washing liquid consumed in this comparative example is significantly increased, and the washing in step (3) needs to be repeated to achieve the same target impurity content level; and the initial activity and stability of the catalyst finally obtained are also significantly reduced.

[0090] Comparative Example 4 (In step (1), the temperature of the first washing liquid is 70° C.)

[0091] The method is carried out in accordance with Example 1, except that the temperature of the first washing liquid used in step (1) of the washing process is 70° C.; steps (2) and (3) are carried out as follows:

[0092] Step (2): The diluted feed liquid is uniformly passed through a suction conveyor filter with separation capability at a certain flow rate (2500 L / h), and is simultaneously rinsed with a second washing liquid to wash away the mother liquid remaining on the solid surface and in the secondary particle accumulation pores. The second washing liquid is 0.05 wt% NaNO at a temperature of 60°C and a pH of 6.5. 3 aqueous solution; step (2) washing until the content of the target impurity in the final filtrate is less than 96% of the initial value;

[0093] Step (3): recover the solid, send it into a stirring container, add pure water twice the mass of the solid and stir it thoroughly, and then separate the solid-liquid mixture through a pressure filtration device; the above washing operation needs to be repeated once, and then a catalyst precursor is obtained. After the catalyst precursor is dried (drying conditions are 120° C., 10 hours), the content of the target impurity in the catalyst precursor is detected to be less than 400 ppm;

[0094] The catalyst precursor was crushed, calcined (calcination conditions were 330 °C, 5 h) and formed, and then used for catalyst activity test. 2 , where the hydrogen-carbon molar ratio is controlled within the range of 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate was 76%. After being heated at 400°C for 5 hours and then cooled to 230°C, the CO conversion rate was 59% and the activity retention rate was 77%.

[0095] The total amount of washing liquid consumed in the above-mentioned washing step in this embodiment is about 7 times the volume of the solid-liquid mixture to be washed. Compared with Example 1, under the condition that other conditions are basically the same, the total amount of washing liquid consumed in this comparative example is significantly increased, and the washing in step (3) needs to be repeated to achieve the same target impurity content level; and the initial activity and stability of the catalyst finally obtained are also significantly reduced.

[0096] Comparative Example 5 (in step (1), the pH of the first washing solution is 6.0)

[0097] The same procedure is carried out as in Example 1, except that in step (1) of the washing process, the pH of the first washing solution used is 6.0. Steps (2) and (3) are carried out as follows:

[0098] Step (2): The diluted feed liquid is uniformly passed through a suction conveyor filter with separation capability at a certain flow rate (2500 L / h), and is simultaneously rinsed with a second washing liquid to wash away the mother liquid remaining on the solid surface and in the secondary particle accumulation pores. The second washing liquid is 0.05 wt% NaNO at a temperature of 60°C and a pH of 6.5. 3 aqueous solution; step (2) washing until the content of the target impurity in the final filtrate is less than 96% of the initial value;

[0099] Step (3): recover the solid, send it into a stirring container, add pure water twice the mass of the solid and stir it thoroughly, and then separate the solid-liquid mixture through a pressure filtration device; the above washing operation needs to be repeated 3 times, and then a catalyst precursor is obtained. After the catalyst precursor is dried (drying conditions are 120° C., 10 hours), the content of the target impurity in the catalyst precursor is detected to be less than 400 ppm;

[0100] The catalyst precursor was crushed, calcined (calcination conditions were 330 °C, 5 h) and formed, and then used for catalyst activity test. 2 , where the hydrogen-carbon molar ratio is controlled within the range of 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate was 76%. After being heated at 400°C for 5 hours and then cooled to 230°C, the CO conversion rate was 59% and the activity retention rate was 77%.

[0101] The total amount of washing liquid consumed in the above-mentioned washing step in this embodiment is about 9 times the volume of the solid-liquid mixture to be washed. Compared with Example 1, under the condition that other conditions are basically the same, the total amount of washing liquid consumed in this comparative example is greatly increased, and the washing in step (3) needs to be repeated multiple times to achieve the same target impurity content level; and the initial activity and stability of the catalyst finally obtained are also significantly reduced.

[0102] Comparative Example 6 (in step (1), the pH of the first washing solution is 9.0)

[0103] The same procedure is carried out as in Example 1, except that in step (1) of the washing process, the pH of the first washing solution used is 9.0. Steps (2) and (3) are carried out as follows:

[0104] Step (2): The diluted feed liquid is uniformly passed through a suction conveyor filter with separation capability at a certain flow rate (2500 L / h), and is simultaneously rinsed with a second washing liquid to wash away the mother liquid remaining on the solid surface and in the secondary particle accumulation pores. The second washing liquid is 0.05 wt% NaNO at a temperature of 60°C and a pH of 6.5. 3 aqueous solution; step (2) washing until the content of the target impurity in the final filtrate is less than 96% of the initial value;

[0105] Step (3): recover the solid, send it into a stirring container, add pure water twice the mass of the solid and stir it thoroughly, and then separate the solid-liquid mixture through a pressure filtration device; the above washing operation needs to be repeated once, and then a catalyst precursor is obtained. After the catalyst precursor is dried (drying conditions are 120° C., 10 hours), the content of the target impurity in the catalyst precursor is detected to be less than 400 ppm;

[0106] The catalyst precursor was crushed, calcined (calcination conditions were 330 °C, 5 h) and formed, and then used for catalyst activity test. 2 , where the hydrogen-carbon molar ratio is controlled within the range of 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate was 78%. After being heated at 400°C for 5 hours and then cooled to 230°C, the CO conversion rate was 61% and the activity retention rate was 78%.

[0107] Compared with Example 1, under the same other conditions, the total consumption of washing liquid in this comparative example is greatly increased, and the washing in step (3) needs to be repeated to achieve the same target impurity content level; and the initial activity and stability of the catalyst obtained in the end are also significantly reduced. The total consumption of washing liquid in the above-mentioned washing step in this example is about 7 times the volume of the solid-liquid mixture to be washed.

[0108] Comparative Example 7 (the temperature of the second washing liquid is 30°C and the pH is 6.0)

[0109] The method is carried out in accordance with Example 1, except that: in step (2) of the washing process, the temperature of the second washing liquid used is 30° C. and the pH is 6.0; and step (3) is carried out as follows:

[0110] Step (3): recover the solid, send it into a stirring container, add pure water twice the mass of the solid and stir it thoroughly, and then separate the solid-liquid mixture through a pressure filtration device; the above washing operation needs to be repeated 4 times, and then a catalyst precursor is obtained. After the catalyst precursor is dried (drying conditions are 120° C., 10 hours), it is detected that the content of the target impurity in the catalyst precursor is less than 400 ppm;

[0111] The catalyst precursor was crushed, calcined (calcination conditions were 330 °C, 5 h) and formed, and then used for catalyst activity test. 2 , where the hydrogen-carbon molar ratio is controlled within the range of 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate was 72%. After being heated at 400°C for 5 hours and then cooled to 230°C, the CO conversion rate was 51% and the activity retention rate was 71%.

[0112] The total amount of washing liquid consumed in the above-mentioned washing step in this embodiment is about 13 times the volume of the solid-liquid mixture to be washed. Compared with Example 1, under the condition that other conditions are basically the same, the total amount of washing liquid consumed in this comparative example is greatly increased, and the washing in step (3) needs to be repeated multiple times to achieve the same target impurity content level; and the initial activity and stability of the catalyst finally obtained are also significantly reduced.

[0113] Comparative Example 8 (the temperature of the second washing liquid is 80°C and the pH is 10.0)

[0114] The method is carried out in accordance with Example 1, except that: in step (2) of the washing process, the temperature of the second washing liquid used is 80° C. and the pH is 10.0; and step (3) is carried out as follows:

[0115] Step (3): recover the solid, send it into a stirring container, add pure water twice the mass of the solid and stir it thoroughly, and then separate the solid-liquid mixture through a pressure filtration device; the above washing operation needs to be repeated 5 times, and then a catalyst precursor is obtained. After the catalyst precursor is dried (drying conditions are 120° C., 10 hours), it is detected that the content of the target impurity in the catalyst precursor is less than 400 ppm;

[0116] The catalyst precursor was crushed, calcined (calcination conditions were 330 °C, 5 h) and formed, and then used for catalyst activity test. 2 , where the hydrogen-carbon molar ratio is controlled within the range of 2.05-2.15) to produce methanol as an example, 230℃, 5MPa, 10000h -1 The initial CO conversion rate is 70%. After heating at 400℃ for 5 hours and then cooling to 230℃, the CO conversion rate is 48% and the activity retention rate is 68%.

[0117] The total amount of washing liquid consumed in the above-mentioned washing step in this embodiment is about 15 times the volume of the solid-liquid mixture to be washed. Compared with Example 1, under the condition that other conditions are basically the same, the total amount of washing liquid consumed in this comparative example is greatly increased, and the washing in step (3) needs to be repeated multiple times to achieve the same target impurity content level; and the initial activity and stability of the catalyst finally obtained are also significantly reduced.

[0118] It is easy to understand that the above embodiments are only examples for clear explanation and do not mean that the present invention is limited thereto. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the present invention.

Claims

1. A method for washing a catalyst precursor, It is characterized in that The steps include: (1) diluting a solid-liquid mixture containing a catalyst precursor obtained in a catalyst preparation process by a precipitation method or an electrolysis method with a first washing liquid having a temperature of 40-60° C. to obtain a diluted feed liquid; the pH of the first washing liquid is 6.5-8.5, and the amount of the first washing liquid is 10-60% of the volume of the solid-liquid mixture; (2) Filter the diluted feed solution and wash the filtered solid portion with a second washing solution having a temperature of 40-70° C., wherein the pH of the second washing solution is 6.5-8.

0.

2. The washing method according to claim 1, It is characterized in that In step (2), the temperature of the second washing solution is 40-60°C, preferably 45-60°C; And / or, the pH of the second washing solution is 7-8.

3. The washing method according to claim 1 or 2, It is characterized in that The first washing liquid or the second washing liquid is one or more of water and an organic solvent, and the organic solvent is preferably one or more of methanol, ethanol, propane, isopropanol, tetrahydrofuran, ether, ethyl acetate, and petroleum ether; The first washing liquid or the second washing liquid optionally contains ≤1.0wt% of a mother liquor component, such as 0.01-1.0wt%, and the mother liquor component is, for example, a nitrate, and the nitrate is, for example, one or more selected from potassium nitrate, sodium nitrate, and ammonium nitrate.

4. The washing method according to any one of claims 1 to 3, It is characterized in that Step (2) is carried out in a device capable of filtering and flushing at the same time, and preferably the device is a suction conveyor belt filter.

5. The washing method according to any one of claims 1 to 4, It is characterized in that In step (2), the flushing is performed until the content of the target impurity in the filtrate is less than 95% of the initial content of the target impurity.

6. The washing method according to any one of claims 1 to 5, It is characterized in that The method further comprises step (3): The solid part obtained in step (2) is further stirred and washed with a third washing liquid and filtered, wherein the amount of the third washing liquid is preferably 2-5 times the mass of the solid part; Preferably, step (3) is performed once or more times until the content of the target impurity meets the preset requirement; Preferably, the third washing liquid is one or more of water and an organic solvent, and the organic solvent is preferably one or more of methanol, ethanol, propane, isopropanol, tetrahydrofuran, ether, ethyl acetate, and petroleum ether; the third washing liquid optionally contains ≤0.05wt% of a mother liquor component, and the mother liquor component is, for example, a nitrate, and the nitrate is, for example, selected from one or more of potassium nitrate, sodium nitrate, and ammonium nitrate; or, the third washing liquid is the same as the second washing liquid.

7. The washing method according to any one of claims 1 to 6, It is characterized in that The precipitation method is single-component precipitation, multi-component co-precipitation, uniform precipitation or immersion precipitation; The catalyst precursor is an organic substance, an inorganic substance, or a mixture of an organic substance and an inorganic substance.

8. The washing method according to any one of claims 1 to 7, It is characterized in that When the solid-liquid mixture containing the catalyst precursor is prepared by the precipitation method or electrolysis method, the solvent used is an aqueous solution with a pH of 6.5-8.5, and 0.05-1wt% of a mother liquor component is added to the aqueous solution. The mother liquor component is, for example, a nitrate, and the nitrate is, for example, one or more selected from potassium nitrate, sodium nitrate, and ammonium nitrate.

9. The washing method according to claim 8, It is characterized in that The solid-liquid mixture containing the catalyst precursor is prepared by a precipitation method or an electrolysis method using a soluble salt containing a metal element; The metal element includes, for example, one or more of copper, zinc, aluminum, magnesium, zirconium, manganese, lanthanum, cerium, nickel, titanium, platinum, palladium, rhodium, and ruthenium; the soluble salt is, for example, nitrate.

10. A method for preparing a catalyst, comprising preparing a solid-liquid mixture containing a catalyst precursor by a precipitation method or an electrolysis method, washing the solid-liquid mixture to obtain a washed catalyst precursor, and then drying and calcining the washed catalyst precursor. It is characterized in that The washing is carried out by the washing method according to any one of claims 1 to 9.