Activated carbon-containing catalysts, methods for their preparation and use
By adopting a four-stage continuous roasting method, the problems of high energy consumption and product non-compliance in the roasting process of activated carbon catalysts have been solved, realizing low-energy, high-efficiency continuous production and improving the performance of catalysts and product qualification rate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2022-12-12
- Publication Date
- 2026-06-23
AI Technical Summary
Existing roasting processes containing activated carbon catalysts have high energy consumption, low product yield, and are prone to activated carbon ashing or incomplete ashing due to improper temperature control. Existing intermittent roasting methods are difficult to achieve continuous production.
A four-stage continuous roasting method is adopted. Under an inert atmosphere, the semi-finished product containing activated carbon catalyst is roasted in a continuous roasting furnace in the first, second, third and fourth stages. The temperature and time are controlled respectively to ensure the temperature gradient and atmosphere protection during the roasting process, prevent activated carbon ashing and improve catalytic performance.
It has achieved continuous production with low energy consumption, improved the yield and catalytic performance of catalysts, prevented activated carbon from being ashed, and greatly improved the product qualification rate.
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalyst preparation technology, specifically to a method for preparing a catalyst containing activated carbon, the activated carbon catalyst obtained by this method, and its application. Background Technology
[0002] Catalysts containing activated carbon require high-temperature oxygen-free treatment (700-1100℃) during the calcination process to prevent the activated carbon from contacting oxygen and causing combustion. Currently, the production of this catalyst is mainly carried out using intermittent calcination. The frequent heating and cooling operations during calcination result in high energy consumption. At the same time, a small amount of oxygen still enters the process, leading to some products failing to meet standards and reducing yield.
[0003] In addition, if the temperature gradient during roasting is set too small or too large, the material is prone to cracking during roasting; if the temperature is set too low, the material will not be roasted completely; if the temperature is set too high, the activated carbon in the material will easily ashing and become waste.
[0004] Against this backdrop, developing a continuous high-temperature oxygen-free calcination preparation technology to achieve continuous production of activated carbon catalysts is of great significance, as it can reduce energy consumption and increase yield. Summary of the Invention
[0005] The purpose of this invention is to overcome the above-mentioned problems existing in the prior art and to provide a catalyst containing activated carbon, its preparation method and application.
[0006] The inventors of this invention conducted in-depth research on the calcination process of activated carbon catalyst semi-finished products and discovered that the control of conditions during the calcination process plays a decisive role in the performance of the obtained activated carbon catalyst. Based on this, by using the method of this invention to perform four-stage continuous calcination under specified temperature and time conditions, the performance of the activated carbon support can be maintained during the calcination process, and the catalytic performance of the obtained activated carbon catalyst can be improved.
[0007] Specifically, the present invention provides a method for preparing a catalyst containing activated carbon, the method comprising: subjecting a semi-finished product containing activated carbon to a first calcination, a second calcination, a third calcination and a fourth calcination in sequence under an inert atmosphere to obtain a catalyst containing activated carbon.
[0008] The activated carbon catalyst contains iron; the first calcination temperature is 820-880℃ for 0.1-2 hours; the second calcination temperature is 870-930℃ for 0.5-5 hours; the third calcination temperature is 900-960℃ for 0.5-5 hours; and the fourth calcination temperature is 840-890℃ for 0.1-2 hours.
[0009] Preferably, the first roasting temperature is 840-860℃; the second roasting temperature is 890-910℃; the third roasting temperature is 920-940℃; and the fourth roasting temperature is 860-880℃.
[0010] Preferably, the first roasting time is 0.2-1 hour; the second roasting time is 0.7-2 hours; the third roasting time is 0.7-2 hours; and the fourth roasting time is 0.2-1 hour.
[0011] Preferably, the steps of sequentially and continuously roasting the semi-finished product containing activated carbon catalyst in the first roasting, second roasting, third roasting and fourth roasting are carried out in a continuous roasting furnace.
[0012] Preferably, the material inlet of the continuous roasting furnace is connected to a semi-finished product silo, and the material outlet is connected to a finished product silo.
[0013] Preferably, the continuous roasting furnace includes four continuously arranged roasting zones, a material conveying section for continuously conveying materials between the roasting zones, and a protective gas supply section for providing an inert atmosphere.
[0014] Preferably, the material conveying section is a conveyor belt or conveyor blades.
[0015] Preferably, the iron content in the activated carbon catalyst is 1-15% by weight, more preferably 7-10% by weight, relative to the total weight of the activated carbon catalyst.
[0016] Preferably, the activated carbon catalyst comprises an activated carbon support and iron supported thereon.
[0017] Preferably, the activated carbon catalyst semi-finished product is activated carbon impregnated with an iron-containing compound.
[0018] The second aspect of the present invention provides an activated carbon-containing catalyst obtained by the preparation method of the first aspect of the present invention described above.
[0019] The third aspect of the present invention provides the application of the activated carbon catalyst described in the second aspect of the present invention in the removal of methyl orange from wastewater.
[0020] Through the above technical solution, the preparation method of the activated carbon-containing catalyst of the present invention has the following beneficial effects:
[0021] (1) By reasonably setting the conditions of four-stage continuous roasting, the roasting effect is guaranteed, the integrity of the catalyst particles during the roasting process is protected, and the ashing caused by excessive local temperature can be prevented, thereby improving the yield and catalytic performance of the obtained activated carbon catalyst.
[0022] (2) The four-stage roasting is carried out continuously, which avoids the large energy consumption caused by frequent heating and cooling operations, and at the same time realizes continuous production and improves preparation efficiency.
[0023] (3) Ensure that the oxygen level is at an extremely low level throughout the roasting process to prevent activated carbon from being ashed and iron from being oxidized, thereby greatly improving the product qualification rate. Detailed Implementation
[0024] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0025] The first aspect of this invention provides a method for preparing an activated carbon-containing catalyst, the method comprising: sequentially subjecting a semi-finished activated carbon-containing catalyst to a first calcination, a second calcination, a third calcination, and a fourth calcination under an inert atmosphere to obtain the activated carbon-containing catalyst; wherein the activated carbon-containing catalyst contains iron; the first calcination temperature is 820-880℃ for 0.1-2 hours; the second calcination temperature is 870-930℃ for 0.5-5 hours; the third calcination temperature is 900-960℃ for 0.5-5 hours; and the fourth calcination temperature is 840-890℃ for 0.1-2 hours.
[0026] According to the present invention, in order to achieve better calcination effect and thus provide a catalyst containing activated carbon with superior catalytic performance, preferably, the first calcination temperature is 840-860℃; the second calcination temperature is 890-910℃; the third calcination temperature is 920-940℃; and the fourth calcination temperature is 860-880℃. According to a preferred embodiment of the present invention, the first calcination temperature is 850℃, the second calcination temperature is 900℃, the third calcination temperature is 930℃, and the fourth calcination temperature is 870℃.
[0027] Specifically, the temperature of the first roasting can be, for example, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃, or 880℃; the temperature of the second roasting can be, for example, 870℃, 880℃, 890℃, 900℃, 910℃, 920℃, or 930℃; the temperature of the third roasting can be, for example, 900℃, 910℃, 920℃, 930℃, 940℃, 950℃, or 960℃; and the temperature of the fourth roasting can be, for example, 840℃, 850℃, 860℃, 870℃, 880℃, or 890℃.
[0028] Furthermore, the temperature of the second calcination is preferably 30-60°C higher than that of the first calcination, the temperature of the third calcination is preferably 20-40°C higher than that of the second calcination, and the temperature of the fourth calcination is preferably 50-70°C lower than that of the third calcination. By setting such temperature gradients, it is more helpful to improve the catalytic performance of the prepared activated carbon catalyst.
[0029] Furthermore, the times for the first, second, third, and fourth roasting can be adjusted independently as needed. Preferably, the first roasting time is 0.2-1 hour; the second roasting time is 0.7-2 hours; the third roasting time is 0.7-2 hours; and the fourth roasting time is 0.2-1 hour. According to a preferred embodiment of the invention, the first roasting time is 0.5 hours, the second roasting time is 1 hour, the third roasting time is 1 hour, and the fourth roasting time is 0.5 hours.
[0030] According to a preferred embodiment of the present invention, the activated carbon-containing catalyst semi-finished product is subjected to a first calcination, a second calcination, a third calcination, and a fourth calcination in sequence using a continuous calcination furnace. By using a continuous calcination furnace for four-stage continuous calcination of the activated carbon-containing catalyst semi-finished product at different temperatures, the heating and cooling processes between calcinations at different temperatures can be rapidly realized. This ensures the particle integrity of the catalyst during the calcination process, while preventing activated carbon ashing while ensuring sufficient calcination, thereby improving the catalytic performance of the obtained activated carbon-containing catalyst.
[0031] In this invention, to ensure the entire roasting process is carried out under an inert atmosphere, the material inlet of the continuous roasting furnace is connected to a semi-finished product silo, and the material outlet is connected to a finished product silo. Both the semi-finished product silo and the finished product silo are configured to provide an inert atmosphere. To further improve the performance of the obtained catalyst, it is preferable that the inert gas flows within the apparatus in the order of finished product silo, continuous roasting furnace, and semi-finished product silo. More preferably, the pressure in the continuous roasting furnace is controlled at 0.15-0.22 MPa, preferably 0.17-0.2 MPa; and the pressure in the finished product silo is controlled at 0.27-0.32 MPa, preferably 0.28-0.31 MPa.
[0032] Furthermore, to ensure the performance of the obtained activated carbon-containing catalyst, the calcined activated carbon-containing catalyst needs to be cooled in the finished product silo before being discharged to prevent oxygen from ashing the activated carbon in the catalyst at high temperatures. Therefore, the temperature of the finished product silo is preferably below 80°C, for example, 60-70°C.
[0033] According to the present invention, the inert atmosphere may be, for example, a nitrogen and / or a rare gas atmosphere, such as a nitrogen atmosphere, so that the iron is not oxidized during the calcination process.
[0034] As a specific type of continuous roasting furnace, it may include four consecutively arranged roasting zones, a material conveying section for continuously transporting materials between the roasting zones, and a protective gas supply section for providing an inert atmosphere. The four consecutively arranged roasting zones respectively provide the temperatures required for the first, second, third, and fourth roasting processes. The duration of the first, second, third, and fourth roasting processes is adjusted by setting the conveying speed of the material conveying section and the length of each roasting zone, thereby completing the roasting process of the present invention.
[0035] According to the present invention, the material conveying unit only needs to be able to convey the semi-finished product containing activated carbon catalyst to the corresponding calcination zone at the required speed so that it can be calcined at the corresponding temperature for an appropriate time. For example, it can be a conveyor belt or a conveyor blade. When using a conveyor blade, the semi-finished product containing activated carbon catalyst can be conveyed by a screw conveyor, and the first calcination, second calcination, third calcination and fourth calcination can be completed in sequence.
[0036] According to the present invention, a higher-performance activated carbon-containing catalyst can be obtained by continuously calcining in four stages at four temperatures. Specifically, the activated carbon-containing catalyst of the present invention may, for example, include an activated carbon support and iron supported thereon, wherein the iron serves as the active component of the catalyst. It is understood that, as needed, the activated carbon-containing catalyst may also contain other active components, such as calcium, sodium, etc., and the content of each other active component may be independently 0.1-10% by weight.
[0037] In this invention, there are no particular limitations on the activated carbon used; it can be selected appropriately according to the needs of the activated carbon-containing catalyst. For example, it can have a specific surface area greater than 800 m². 2 The activated carbon exhibits properties such as a pore volume greater than 0.6 mL / g. There are no specific requirements regarding the source of the activated carbon; it can be prepared by carbonizing carbon-containing raw materials or obtained commercially.
[0038] As a semi-finished product containing activated carbon catalyst, activated carbon impregnated with an iron-containing compound can be used, for example. Specific iron-containing compounds can be, for example, ferric nitrate, ferric chloride, etc. The semi-finished product containing activated carbon catalyst can be obtained by appropriately mixing an iron-containing compound solution with an activated carbon support through spraying, impregnation, stirring, or other methods. To improve the calcination effect, the moisture content of the semi-finished product containing activated carbon catalyst can be controlled by drying at 50-80°C. Preferably, the moisture content of the semi-finished product containing activated carbon catalyst after drying is reduced by more than 50% by weight, and more preferably by more than 60% by weight.
[0039] The amount of iron-containing compound used can be appropriately determined according to the required iron loading of the catalyst. In this invention, the iron content in the activated carbon catalyst, relative to the total weight of the activated carbon catalyst, can be, for example, 1-15% by weight, preferably 7-10% by weight.
[0040] The second aspect of the present invention provides an activated carbon-containing catalyst obtained by the preparation method of the first aspect of the present invention described above.
[0041] The third aspect of the present invention provides the application of the activated carbon catalyst described in the second aspect of the present invention in the removal of methyl orange from wastewater.
[0042] The activated carbon catalyst prepared by the method of the present invention can be used for catalytic oxidation, hydrogenation and other applications. For example, it can be used to degrade recalcitrant organic pollutants such as methylene blue and methyl orange. The decomposition efficiency of methyl orange can reach more than 95%, and it has broad application prospects in the field of recalcitrant organic wastewater.
[0043] The present invention will be described in detail below through examples. In the following examples, the ash content of activated carbon was determined by GB / T12496.3, and the lateral pressure strength was determined by Q / SH 361 926. The methyl orange removal rate was determined by a catalytic wet hydrogen peroxide oxidation test. The specific reaction conditions were as follows: 150.0 mL methyl orange solution (50 mg / L), pH 3.0, reaction temperature 80℃, catalyst dosage 0.10 g, hydrogen peroxide (volume fraction 30%) dosage 3.6 mL, and reaction time 120 minutes. After the reaction was completed, the sample was filtered through a 0.45 μm microporous membrane, and the concentration of the methyl orange solution was determined by ultraviolet-spectrum spectrophotometry. The methyl orange removal rate X was calculated according to the following formula:
[0044] X = (C0 - C) / C0 × 100%
[0045] In the formula, X is the methyl orange removal rate (%), C0 is the initial concentration of the methyl orange solution (mg / L), and C is the concentration of the methyl orange solution when the reaction is complete (mg / L).
[0046] Example 1
[0047] After thoroughly impregnating the activated carbon support (60-80 mesh) with a 10% by weight ferric nitrate solution, dry it at 70°C to evaporate more than 60% of the moisture, and obtain a semi-finished product containing activated carbon catalyst.
[0048] A continuous roasting process for a semi-finished product containing activated carbon catalyst was carried out in a nitrogen atmosphere using a continuous roasting furnace. The continuous roasting furnace has four continuously arranged roasting zones, spiral conveyor blades for continuously conveying the material between the roasting zones, and a protective gas supply unit for providing an inert atmosphere. Under a nitrogen atmosphere, the semi-finished product containing activated carbon catalyst was fed into the continuous roasting furnace from the semi-finished product silo. The temperatures and times for the four-stage continuous roasting were as follows: (1) 850°C, 0.5 hours; (2) 900°C, 1 hour; (3) 930°C, 1 hour; (4) 870°C, 0.5 hours. After roasting, the obtained activated carbon catalyst (containing 8% by weight of iron) was fed into the finished product silo, cooled to 60°C in a nitrogen atmosphere, and then discharged.
[0049] The performance of the obtained activated carbon catalyst was tested, and the results are shown in Table 1.
[0050] Example 2
[0051] The activated carbon catalyst semi-finished product was subjected to four-stage continuous calcination according to the method of Example 1, with the only difference being that the temperatures of the four-stage continuous calcination were as follows: (1) 840℃, 1 hour; (2) 890℃, 1.5 hours; (3) 920℃, 1.5 hours; (4) 860℃, 1 hour. The performance test results of the obtained activated carbon catalyst are shown in Table 1.
[0052] Example 3
[0053] The activated carbon catalyst semi-finished product was subjected to four-stage continuous calcination according to the method of Example 1, with the only difference being that the temperatures of the four-stage continuous calcination were as follows: (1) 860℃, 0.3 hours; (2) 910℃, 0.7 hours; (3) 940℃, 0.7 hours; (4) 880℃, 0.3 hours. The performance test results of the obtained activated carbon catalyst are shown in Table 1.
[0054] Example 4
[0055] The activated carbon catalyst semi-finished product was subjected to four-stage continuous calcination according to the method of Example 1, with the only difference being that the temperatures of the four-stage continuous calcination were as follows: (1) 830℃, 0.5 hours; (2) 920℃, 1 hour; (3) 930℃, 1 hour; (4) 870℃, 0.5 hours. The performance test results of the obtained activated carbon catalyst are shown in Table 1.
[0056] Example 5
[0057] The activated carbon catalyst semi-finished product was subjected to four-stage continuous calcination according to the method of Example 1, with the only difference being that the temperatures of the four-stage continuous calcination were as follows: (1) 850℃, 0.5 hours; (2) 900℃, 1 hour; (3) 910℃, 1 hour; (4) 890℃, 0.5 hours. The performance test results of the obtained activated carbon catalyst are shown in Table 1.
[0058] Comparative Example 1
[0059] The activated carbon catalyst semi-finished product was calcined in four stages in a conventional calcination furnace under a nitrogen atmosphere. The heating / cooling rate at different stages was 5℃ / min. The temperatures and times for the four stages of calcination were as follows: (1) 850℃, 0.5 hours; (2) 900℃, 1 hour; (3) 930℃, 1 hour; (4) 870℃, 0.5 hours. The performance test results of the obtained activated carbon catalyst are shown in Table 1.
[0060] Comparative Example 2
[0061] The activated carbon catalyst semi-finished product was continuously calcined according to the method of Example 1, except that the calcination was carried out at 900°C for 3 hours. The performance test results of the obtained activated carbon catalyst are shown in Table 1.
[0062] Comparative Example 3
[0063] The activated carbon catalyst semi-finished product was subjected to four-stage continuous calcination according to the method of Example 1, with the only difference being that the temperatures of the four-stage continuous calcination were as follows: (1) 890℃, 0.5 hours; (2) 900℃, 1 hour; (3) 970℃, 1 hour; (4) 870℃, 0.5 hours. The performance test results of the obtained activated carbon catalyst are shown in Table 1.
[0064] Comparative Example 4
[0065] The activated carbon catalyst semi-finished product was subjected to four-stage continuous calcination according to the method of Example 1, with the only difference being that the temperatures of the four-stage continuous calcination were as follows: (1) 870℃, 0.5 hours; (2) 940℃, 1 hour; (3) 890℃, 1 hour; (4) 850℃, 0.5 hours. The performance test results of the obtained activated carbon catalyst are shown in Table 1.
[0066] Table 1
[0067] serial number Ash content, % Methyl orange removal rate, % Crushing strength, N / cm Example 1 5.1 97.5 161 Example 2 5.8 96.3 165 Example 3 6.5 95.2 162 Example 4 9.5 90.3 125 Example 5 10.3 89.5 136 Comparative Example 1 17.5 73.6 108 Comparative Example 2 16.3 76.0 106 Comparative Example 3 18.9 70.1 97 Comparative Example 4 18.3 72.3 101
[0068] As can be seen from the results in Table 1, Examples 1-5 using the preparation method of the present invention have lower ash content, higher catalytic performance, and higher crushing strength, and the catalyst has a uniform color, indicating that it has not been oxidized; while Comparative Example 1, which does not use the continuous roasting method of the present invention, or Comparative Examples 2-4, which do not use the roasting conditions specified in the present invention, have higher ash content, worse catalytic performance, and worse crushing strength.
[0069] Furthermore, by using more preferred calcination conditions in Examples 1-3, the ash content can be further reduced and the catalytic performance and crushing strength can be improved based on Examples 4-5.
[0070] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A method for preparing a catalyst containing activated carbon, characterized in that, The preparation method includes: under an inert atmosphere, the semi-finished product containing activated carbon catalyst is subjected to a first calcination, a second calcination, a third calcination and a fourth calcination in sequence to obtain the activated carbon catalyst; The activated carbon catalyst includes an activated carbon support and iron supported thereon. The first roasting temperature is 820-880℃, and the time is 0.1-2 hours; the second roasting temperature is 870-930℃, and the time is 0.5-5 hours; the third roasting temperature is 900-960℃, and the time is 0.5-5 hours; the fourth roasting temperature is 840-890℃, and the time is 0.1-2 hours. The activated carbon catalyst semi-finished product is activated carbon impregnated with iron-containing compounds.
2. The preparation method according to claim 1, wherein, The first roasting temperature is 840-860℃; the second roasting temperature is 890-910℃; the third roasting temperature is 920-940℃; and the fourth roasting temperature is 860-880℃.
3. The preparation method according to claim 1 or 2, wherein, The first roasting time is 0.2-1 hour; the second roasting time is 0.7-2 hours; the third roasting time is 0.7-2 hours; and the fourth roasting time is 0.2-1 hour.
4. The preparation method according to claim 1, wherein, The semi-finished product containing activated carbon catalyst is subjected to a first roasting, a second roasting, a third roasting, and a fourth roasting in sequence through a continuous roasting furnace.
5. The preparation method according to claim 4, wherein, The material inlet of the continuous roasting furnace is connected to the semi-finished product silo, and the material outlet is connected to the finished product silo.
6. The preparation method according to claim 4, wherein, The continuous roasting furnace includes four continuously arranged roasting zones, a material conveying section for continuously conveying materials between the roasting zones, and a protective gas supply section for providing an inert atmosphere.
7. The preparation method according to claim 6, wherein, The material conveying unit is a conveyor belt or conveyor blades.
8. The preparation method according to claim 1, wherein, The iron content in the activated carbon catalyst is 1-15% by weight relative to the total weight of the activated carbon catalyst.
9. The preparation method according to claim 8, wherein, The iron content in the activated carbon catalyst is 7-10% by weight relative to the total weight of the activated carbon catalyst.
10. A carbon-containing catalyst obtained by any one of the preparation methods according to claims 1-9.
11. The application of the activated carbon catalyst according to claim 10 in the removal of methyl orange from wastewater.