An alkali metal catalytic particle and a preparation method thereof

Abstract

The present application provides an alkali metal catalytic particle and a preparation method thereof, comprising the following steps: Mixing raw materials according to the mass ratio of dolomite: calcium carbonate: calcium oxide: calcium hydroxide being (10-30):(20-30):(25-50):(15-20) to obtain a mixture A; Mixing raw materials according to the mass ratio of cement: oxalic acid: aluminum dihydrogen phosphate being (5-10):(3-10):(5-10) to obtain a composite binder; Mixing the mixture A and the composite binder evenly according to the mass ratio of 100:(5-20) to obtain a mixture B; Granulating 60-80 wt% of the mixture B and 20-40 wt% of an alkali metal-based catalyst to obtain a green body of the alkali metal catalytic particle; Drying the green body of the alkali metal catalytic particle and then performing heat treatment in a CO2 atmosphere, where the heat treatment conditions are holding at 350-600 °C for 6-9 h, and the alkali metal catalytic particle is obtained after cooling. The catalytic particle of the present application is easier to store and can be transported with water in the form of particles to participate in processes such as biomass catalytic gasification and coal char catalytic gasification, and it is not easy to corrode equipment and pipelines.

Description

Technical Field

[0001] This application belongs to the field of alkali metal catalysts. More specifically, it relates to an alkali metal catalytic particle and a preparation method thereof. Background Art

[0002] A catalyst refers to a substance that can effectively promote or enhance the chemical reaction process to achieve a more efficient utilization effect without participating in the reaction itself. There are many types of catalysts, mainly including metal catalysts, acid catalysts, alkali catalysts, and enzyme catalysts, etc.

[0003] As an important type of catalyst in alkali catalysts, alkali metal catalysts have broad application prospects. In the field of organic synthesis, alkali metal catalysts can catalyze organic reactions to improve the reaction rate and yield. For example, the patented technology of "Method for Producing Ethylene Glycol by Hydrolyzing Ethylene Carbonate" (202310124383.2) uses ethylene carbonate and water as raw materials and alkali metal carbonate as a catalyst to hydrolyze and produce ethylene glycol. In addition, alkali metal catalysts can catalyze the condensation reaction of alcohols with aldehydes or ketones to form ether compounds; they can also catalyze the addition reaction of esters, the hydrogenation reaction of olefins, etc. In the field of energy conversion, it can catalyze the oxygen reduction reaction in fuel cells to improve the energy conversion efficiency of the battery; it can also catalyze the generation and oxidation reaction of hydrogen to promote the utilization of hydrogen energy. The patented technology of "An Alkali Metal Catalyst and Its Application" (201811624775.0) mixes alkali metal carbonate, olivine, and water evenly and seals them, and then prepares the alkali metal catalyst after aging, drying, and calcining, which is used for catalytic de-coking of straw biomass. In addition, alkali metal catalysts also play an important role in the fields of petroleum and coal chemical industry. Alkali metal catalysts can participate in the catalytic cracking process of petroleum, promoting the cracking reaction of heavy and inferior feedstock oils, so that petroleum resources can be effectively utilized. At the same time, alkali metal catalysts can also promote the coal char gasification reaction to meet the needs of the development of coal chemical industry. The patented technology of "A Method for Improving the Catalytic Gasification Activity of Coal and the Recovery Rate of Catalysts" (201410548041.4) impregnates and loads the acid-deashed coal with potassium carbonate catalyst, and then gasifies the loaded catalyst sample at a temperature of 650°C - 750°C in a high-pressure fluidized bed, using the catalytic effect of potassium carbonate to promote the gasification of coal.

[0004] Because alkali metal catalysts have extremely strong hygroscopicity, they will absorb water and agglomerate during storage, affecting the dispersibility of the catalyst, and thus affecting the catalytic effect. On the other hand, when alkali metal catalysts are used for biomass catalytic gasification and coal char catalytic gasification, they usually need to be transported through water and released when they reach the designated position and suitable catalytic conditions (above 650°C). Because its aqueous solution is strongly alkaline, it corrodes equipment and pipelines during the transportation process, greatly limiting its application. Summary of the Invention

[0005] The purpose of this application is to provide an alkali metal catalytic particle and its preparation method to solve the problems of moisture absorption during storage and corrosion of pipelines during water transportation.

[0006] To achieve the above purpose, in the first aspect of this application, a preparation method of an alkali metal catalytic particle is provided, including the following steps:

[0007] Mix ingredients according to the mass ratio of dolomite:calcium carbonate:calcium oxide:calcium hydroxide being (10 - 30):(20 - 30):(25 - 50):(15 - 20) to obtain mixture A;

[0008] Mix ingredients according to the mass ratio of cement:oxalic acid:aluminum dihydrogen phosphate being (5 - 10):(3 - 10):(5 - 10) to obtain a composite binder;

[0009] Mix the mixture A and the composite binder evenly according to the mass ratio of 100:(5 - 20) to obtain mixture B;

[0010] Mix 60 - 80wt% of the mixture B with 20 - 40wt% of an alkali metal - type catalyst and granulate to obtain an alkali metal catalytic particle green body;

[0011] Dry the alkali metal catalytic particle green body, and then place it in a CO₂ atmosphere for heat treatment. The heat treatment conditions are to keep warm at 350 - 600 °C for 6 - 9 h, and then obtain the alkali metal catalytic particle after cooling.

[0012] Further, the alkali metal - type catalyst includes at least one of NaOH, KOH, Na₂CO₃, and K₂CO₃.

[0013] Further, the drying time is 1 - 2 d.

[0014] Further, the heating rate during the heat treatment process is 5 - 10 °C / min.

[0015] Further, the particle sizes of the raw materials in the mixture A are respectively: dolomite ≤ 80 μm, calcium hydroxide ≤ 58 μm, and both calcium carbonate and calcium oxide ≤ 38 μm.

[0016] Further, in the composite binder: the cement is Secar cement with a particle size ≤ 90 μm; the purity of oxalic acid ≥ 99.4%, and the purity of aluminum dihydrogen phosphate is 91 - 97%.

[0017] Further, the mixing and granulation are carried out in a disk granulator.

[0018] Further, the mixing and granulation process is: rotate at a speed of 50 - 70 r / min for 2 - 5 min.

[0019] In the second aspect of the present application, an alkali metal catalytic particle is provided, which is prepared by the preparation method described in any one of the above.

[0020] Compared with the prior art, the present application has the following technical effects:

[0021] In the preparation method of an alkali metal catalytic particle of the present application, a mixture and an alkali metal catalyst are mixed and granulated to encapsulate the alkali metal catalyst, and a coating shell layer is formed on the surface of the alkali metal catalyst. During the heat treatment process, the shell layer raw material reacts at high temperature to generate calcium carbonate, and the volume expands during this process, blocking the pores of the shell layer, making the shell layer dense and waterproof, which can effectively block the penetration of water into the catalyst interior and prevent the reverse osmosis of the catalyst core to release strongly alkaline alkali metal catalysts into the water. The catalytic particles prepared in the present application are not easy to absorb moisture, are easier to store, and can be transported with water in the form of particles, and are not easy to corrode equipment and pipelines.

[0022] In the preparation method of an alkali metal catalytic particle of the present application, raw materials such as dolomite, calcium carbonate, calcium oxide, and calcium hydroxide are used to encapsulate the alkali metal catalyst, with low cost; after the encapsulated catalytic particles are transported with water to the target catalytic area, the empty shells of the particles will not cause pollution and damage to the environment after the catalyst is released, which is environmentally friendly.

[0023] In the preparation method of an alkali metal catalytic particle of the present application, first, mixture A and a composite binder are uniformly mixed to obtain mixture B during the preparation process; during the granulation process, mixture B and the catalyst are placed in a disk granulator, and by controlling the rotation speed and time of the disk granulator, the thickness and uniformity of the alkali metal catalytic particles can be controlled. The preparation process is simple and easy for industrial production.

[0024] Calcium carbonate in the shell layer of the alkali metal catalytic particles prepared in the present application will decompose into calcium oxide when heated at high temperature, releasing the core alkali metal catalyst. In addition, calcium oxide itself also has certain catalytic effects, and when participating in the catalytic gasification process of biomass and char, it has a synergistic effect on the catalytic performance of the alkali metal catalyst. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is an optical microscopic image after drying of an alkali metal catalytic particle blank provided in Embodiment 1 of the present application;

[0027] Figure 2 For Figure 1 the optical micrograph of the alkali metal catalytic particle green body after heat treatment. Detailed implementation manners

[0028] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the present application will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] In the present application, "at least one" means one or more, and "a plurality" means two or more. "At least one (item)" or similar expressions thereof refer to any combination of these items, including any combination of single (item) or plural items. For example, "at least one (item) of a, b, or c", or, "at least one (item) of a, b, and c" can all represent: a, b, c, a-b (that is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple respectively.

[0030] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0031] The weights of the relevant components mentioned in the specification of the embodiments of the present application not only can refer to the specific contents of each component, but also can represent the proportional relationship of the weights between each component. Therefore, as long as the contents of the relevant components in the specification of the embodiments of the present application are enlarged or reduced in proportion, they are within the scope disclosed in the specification of the embodiments of the present application. Specifically, the mass mentioned in the specification of the embodiments of the present application can be mass units well-known in the chemical industry such as μg, mg, g, kg, etc.

[0032] The following uses multiple specific embodiments to illustrate an alkali metal catalyst particle and its preparation method according to the embodiments of the present application.

[0033] Embodiment 1

[0034] Embodiment 1 of the present application provides an alkali metal catalyst particle and its preparation method, including the following steps:

[0035] Step 1: Mix the ingredients according to the mass ratio of dolomite: calcium carbonate: calcium oxide: calcium hydroxide of 10:20:50:20 to obtain a mixture A;

[0036] Step 2: Mix the ingredients according to the mass ratio of cement: oxalic acid: aluminum dihydrogen phosphate of 10:10:5 to obtain a composite binder;

[0037] Step 3, mix the mixture A and the composite binder in a mass ratio of 100:5 to obtain a mixture B;

[0038] Step 4: Place 60 wt% of the mixed material B in a disc granulator, then add 40 wt% of the NaOH catalyst into the disc granulator, rotate it at a speed of 50 r / min for 5 minutes, take it out, and obtain an alkali metal catalyst particle body;

[0039] Step 5: After drying the alkali metal catalytic particle body for 1 day, place it in a CO2 atmosphere, heat it to 550°C at a rate of 5°C / min, keep it at that temperature for 6 hours, and naturally cool it to room temperature to obtain alkali metal catalytic particles.

[0040] Example 2

[0041] Embodiment 2 of the present application provides an alkali metal catalytic particle and a preparation method thereof, comprising the following steps:

[0042] Step 1: Mix dolomite: calcium carbonate: calcium oxide: calcium hydroxide in a mass ratio of 17:23:41:19 to obtain a mixture A;

[0043] Step 2: Mix cement, oxalic acid and aluminum dihydrogen phosphate in a mass ratio of 8:7:6 to obtain a composite binder;

[0044] Step 3, mix the mixture A and the composite binder in a mass ratio of 100:10 to obtain a mixture B;

[0045] Step 4: Place 68 wt% of the mixed material B in a disc granulator, then add 32 wt% of the KOH catalyst into the disc granulator, rotate it at a speed of 58 r / min for 4 min, take it out, and obtain an alkali metal catalyst particle body;

[0046] Step 5: After drying the alkali metal catalytic particle body for 1.5 days, place it in a CO2 atmosphere, heat it to 600°C at a rate of 6°C / min, keep it at that temperature for 7 hours, and naturally cool it to room temperature to obtain alkali metal catalytic particles.

[0047] Example 3

[0048] Embodiment 3 of the present application provides an alkali metal catalytic particle and a preparation method thereof, comprising the following steps:

[0049] Step 1: Mix dolomite: calcium carbonate: calcium oxide: calcium hydroxide in a mass ratio of 24:26:33:17 to obtain a mixture A;

[0050] Step 2: Mix cement, oxalic acid and aluminum dihydrogen phosphate in a mass ratio of 6:5:8 to obtain a composite binder;

[0051] Step 3: Mix the mixture A and the composite binder evenly at a mass ratio of 100:15 to obtain the mixture B;

[0052] Step 4: Place 75 wt% of the mixture B in a disk granulator, then add 25 wt% of the Na2CO3 catalyst to the disk granulator, rotate at a speed of 65 r / min for 3 min, take out, and obtain the alkali metal catalytic particle green body;

[0053] Step 5: After drying the alkali metal catalytic particle green body for 2 days, place it in a CO2 atmosphere, heat it to 480 °C at a rate of 8 °C / min, keep it warm for 8 h, and naturally cool it to room temperature to obtain the alkali metal catalytic particles.

[0054] Example 4

[0055] Example 4 of the present application provides an alkali metal catalytic particle and a preparation method thereof, including the following steps:

[0056] Step 1: Mix and blend according to the mass ratio of dolomite: calcium carbonate: calcium oxide: calcium hydroxide of 30:30:25:15 to obtain the mixture A;

[0057] Step 2: Mix and blend according to the mass ratio of cement: oxalic acid: aluminum dihydrogen phosphate of 5:3:10 to obtain the composite binder;

[0058] Step 3: Mix the mixture A and the composite binder evenly at a mass ratio of 100:20 to obtain the mixture B;

[0059] Step 4: Place 80 wt% of the mixture B in a disk granulator, then add 20 wt% of the K2CO3 catalyst to the disk granulator, rotate at a speed of 70 r / min for 2 min, take out, and obtain the alkali metal catalytic particle green body;

[0060] Step 5: After drying the alkali metal catalytic particle green body for 2 days, place it in a CO2 atmosphere, heat it to 350 °C at a rate of 10 °C / min, keep it warm for 9 h, and naturally cool it to room temperature to obtain the alkali metal catalytic particles.

[0061] The optical micrograph of the dried alkali metal catalytic particle green body in Example 1 of the present application is as Figure 1 shown, and the optical micrograph of the alkali metal catalytic particle green body after further heat treatment is as Figure 2 shown. It can be seen from Figure 1 , Figure 2 that the preparation method in Example 1 of the present application has formed a well - formed encapsulation coating on the surface of the alkali metal - based catalyst.

[0062] Since the core of the alkali metal catalytic particles prepared in this application is a strongly basic alkali metal catalyst, in order to determine whether the preparation method of this application can effectively encapsulate the core catalyst, the alkali metal catalytic particles prepared in Examples 1-4 of this application were taken and soaked in water, and water mixtures with a content of 10 wt% were prepared. After standing for 2 h, the pH value changes of each group were tested. At the same time, the pH values of the 10 wt% alkali metal catalyst solutions before coating of each group were used as a control. The test results are shown in Table 1 below.

[0063] Since the alkali metal catalytic particles prepared in this application need to be transported with water during use, and it is required that the catalytic particles cannot be broken during the water transportation process, and they need to have good strength. The alkali metal catalytic particles prepared in Examples 1-4 of this application were taken and passed through a pipeline with a length of 2 m and a diameter of 20 mm, and the flow rate was maintained at 1.1 m / s, so that the catalytic particles circulated and flowed with the water in this pipeline for scouring. Every 1 m 3 The content of catalyst particles in water was 5000 g. The breakage rate of each group of catalytic particles after 2 h of cyclic scouring was tested to characterize their water scouring resistance. The test results are shown in Table 1 below.

[0064] In addition, after the catalytic particles are transported with water to the target catalytic area, the shell layer ruptures at high temperature, the catalyst core is released, and at the same time the outer shell catalyzes and enhances the efficiency. In order to characterize the effective rupture degree of the catalytic particles prepared in the examples of this application when reaching the target catalytic area, the shell rupture temperature was used to characterize the release temperature of the catalyst particles. The alkali metal catalytic particles prepared in Examples 1-4 of this application were taken and placed in a box furnace at a certain temperature for 3 min, and then taken out to observe the particle breakage situation. The temperature corresponding to the complete breakage of the particles was used as the release temperature of the catalyst particles. The test results are shown in Table 1 below.

[0065] Table 1

[0066]

[0067] As can be seen from Table 1 above, after coating (encapsulation), the pH value of the water mixture of 10 wt% catalytic particles decreased significantly, indicating that the preparation method of the examples of this application can effectively encapsulate the alkali metal catalyst, making the encapsulated catalytic particles easier to store and transport with water, and will not corrode equipment and pipelines (general equipment and pipelines are not easily corroded when the pH is between 9.5 and 11.0).

[0068] The water scouring resistance test shows that the catalytic particles prepared in the examples of this application have good structural strength and are not easily broken during the water transportation process.

[0069] The test results of the shell rupture temperature of the catalytic particles show that after the catalytic particles prepared in the embodiments of the present application are transported to the target catalytic zone and are heated at a high temperature in the target catalytic zone, their shells are very easy to rupture, so that the alkali metal catalysts encapsulated in the catalytic particles are efficiently released to complete the catalytic process.

[0070] The above embodiments only express several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for preparing an alkali metal catalytic particle, characterized in that, It includes the following steps: Mix ingredients according to the mass ratio of dolomite: calcium carbonate: calcium oxide: calcium hydroxide being (10~30):(20~30):(25~50):(15~20) to obtain mixture A; Mix ingredients according to the mass ratio of cement: oxalic acid: aluminum dihydrogen phosphate being (5~10):(3~10):(5~10) to obtain a composite binder; Mix the mixture A and the composite binder evenly according to the mass ratio of 100:(5~20) to prepare mixture B; Mix 60~80wt% of the mixture B with 20~40wt% of an alkali metal catalyst and granulate to obtain an alkali metal catalytic particle green body; Dry the alkali metal catalytic particle green body, and then place it in a CO2 atmosphere for heat treatment. The heat treatment conditions are to keep the temperature at 350~600°C for 6~9h, and an alkali metal catalytic particle is obtained after cooling; The alkali metal catalyst includes at least one of NaOH, KOH, Na2CO3, and K2CO3; The granulation process is: rotate at a speed of 50~70r / min for 2~5min.

2. The preparation method of an alkali metal catalytic particle according to claim 1, wherein The drying time is 1~2d.

3. The preparation method of an alkali metal catalytic particle as claimed in claim 1, wherein, The heating rate during the heat treatment process is 5~10°C / min.

4. The preparation method of an alkali metal catalytic particle according to claim 1, wherein, The particle sizes of the raw materials in the mixture A are respectively: dolomite ≤80μm, calcium hydroxide ≤58μm, and both calcium carbonate and calcium oxide ≤38μm.

5. The preparation method of an alkali metal catalytic particle according to claim 1, characterized in that, In the composite binder: the cement is Secar cement with a particle size ≤90μm; the purity of oxalic acid ≥99.4%, and the purity of aluminum dihydrogen phosphate is 91~97%.

6. The preparation method of an alkali metal catalytic particle according to claim 1, wherein, The granulation is carried out in a disk granulator.

7. An alkali metal catalytic particle, characterized in that, Prepared by using the preparation method described in any one of claims 1-6.

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