A kind of renewable 1-butene catalyst and preparation method thereof
By using renewable catalysts composed of alumina, silicon oxide and tungsten oxide, the problems of high reaction temperature, large energy consumption and low selectivity of 1-butene in 1-butene are solved, and low temperature and efficient 1-butene production are achieved, reducing costs and improving product quality.
Patent Information
- Application Number
- CN202111176864.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-10-09
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2041-10-09
AI Technical Summary
In the existing 1-butene production, the dehydration reaction temperature is high, the energy consumption is large, and the 1-butene product selectivity is low, and there are many by-products.
A renewable 1-butene catalyst is prepared by using three components: alumina, silicon oxide and tungsten oxide as the activity center. By adjusting the component ratio and preparation process, the acidity and activity of the catalyst are improved.
It has achieved the reduction of the dehydration reaction temperature, the increase of 1-butene selectivity and raw material conversion rate, the reduction of production costs, and the improvement of product quality.
Abstract
Description
Technical Field
[0001] The invention discloses a regenerable 1-butene catalyst and a preparation method thereof, belonging to the technical field of catalysts for 1-butene production. Background Art
[0002] 1-Butene can be used as an important comonomer of ethylene, can also be polymerized by itself to produce poly-1-butene, and can also produce valeraldehyde and pentanol through carbonylation reaction. With the rapid development of my country's petrochemical industry, the demand for high-purity 1-butene is increasing day by day. At present, 1-butene is mainly produced by distillation process. In the actual production process, the 1-butene device uses carbon four after ether as raw material, first passes through a light removal tower to separate light components such as carbon three and isobutane in carbon four after ether, and then enters a heavy removal tower to obtain high-purity 1-butene from the top of the tower. The above-mentioned double-tower 1-butene separation system in series requires two distillation towers, and because the height of a single distillation tower is too high, a single distillation tower is generally divided into two, generally in the form of four towers, which makes the separation process long, energy consumption high, and the equipment occupies a large area and the investment cost high.
[0003] In another production method, 1-olefins are prepared by dehydrating alcohols to prepare olefins.
[0004] There are many types of catalysts that can be used for the dehydration of alcohols. According to current reports, most solid acid catalysts and solid base catalysts can be used for the dehydration of alcohols to generate corresponding olefins or ethers.
[0005] Generally speaking, solid acid catalysts are more active than solid base catalysts, so solid acid catalysts are more commonly used in such reactions. Catalysts for alcohol dehydration are mainly composed of oxide catalysts, molecular sieve catalysts, cation exchange resins and heteropolyacid catalysts. Activated alumina is the most important dehydration catalyst in the production of 1-butene, and the cost of this catalyst is relatively low. However, it has disadvantages such as high reaction temperature and high energy consumption. In order to reduce the reaction temperature and device energy consumption, many scholars have developed new catalysts, such as H-ZSM-5 molecular sieves with different silicon-aluminum ratios, modified H-ZSM-5 molecular sieves, modified alumina, molybdophosphoric acid, activated carbon-supported tungstophosphoric acid and other catalysts. Although a lot of work has been done in catalyst research and development, the reaction temperature still needs to be higher than 300°C, and the 1-butene content in the reaction product is relatively low, and there are more alkane products such as methane, isobutane and n-butane. Summary of the invention
[0006] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a regenerable 1-butene catalyst with low dehydration reaction temperature, high reaction raw material conversion rate and high 1-butene product selectivity and a preparation method thereof.
[0007] The technical solution adopted by the present invention to solve the technical problem is: a regenerable 1-butene catalyst, characterized in that it comprises, by weight: 30-90% aluminum oxide, 5-65% silicon oxide, and 5-30% tungsten oxide.
[0008] At the same time, the alcohol dehydration catalyst is prepared with silicon oxide, aluminum oxide and tungsten oxide as active centers. The introduction of silicon oxide effectively improves the acidity of the catalyst surface. After the introduction of tungsten oxide at the same time, the number of acid sites on the catalyst surface can be increased on the basis of silicon oxide, and the acidity of the catalyst is more significantly enhanced. The dehydration ability of the catalyst in the alcohol dehydration reaction is greatly enhanced, and the catalyst activity is significantly increased.
[0009] More preferably, the material comprises, by weight: 40-70% aluminum oxide, 20-55% silicon oxide, and 10-20% tungsten oxide.
[0010] The preferred weight composition has a stronger active center coordination effect and a stronger catalytic dehydration ability.
[0011] The method for preparing the above-mentioned regenerable 1-butene catalyst is characterized by comprising the following steps:
[0012] 1) Pseudo-boehmite, 0.02-0.1 parts of silicon dioxide, 0.02-0.1 parts of sesbania powder and 0.02-0.1 parts of citric acid are uniformly mixed by weight, and calcined to obtain a catalyst matrix; wherein the molar ratio of pseudo-boehmite to silicon dioxide is 2-5:1;
[0013] 2) Dissolve ammonium tungstate in water to make a solution with a mass fraction of 3-10%, and add dilute hydrochloric acid to adjust the pH of the solution to 3-4;
[0014] 3) immersing the catalyst substrate prepared in step 1) in deionized water for 5 to 30 minutes and in the solution obtained in step 2) for 5 to 60 minutes; wherein the weight ratio of the catalyst substrate to the deionized water is 0.4 to 1:1, and the mass ratio of the catalyst substrate to the solution is 1:2 to 5;
[0015] 4) The impregnated solid obtained in step 3) is air-dried, dried, and calcined to obtain a regenerable 1-butene catalyst.
[0016] Alumina and silica are used as mixed matrices, and tungsten is additionally loaded. Pseudo-boehmite and silica are calcined to form alumina and silica, which can ensure the structural strength of the matrix and form sufficient gaps inside to increase the contact area between alumina and silica; then the ammonium tungstate is impregnated and calcined to form tungsten oxide, while preventing tungsten oxide from gathering inside, thereby improving the catalytic effect of tungsten; pre-impregnation with water can prevent excessive tungsten elements from entering the carrier due to direct impregnation of ammonium tungstate, ensuring that tungsten is attached to the outer layer of the matrix, further improving the catalytic effect of tungsten as an active center. The above-mentioned catalyst matrix impregnation mass ratio can ensure the impregnation effect while reducing waste liquid discharge.
[0017] Preferably, after the mixing in step 1) is uniformly performed, an extruder is used to extrude the mixture into a cylindrical shape with a diameter of 1.5-3 mm and a length of 20-40 mm.
[0018] The cylindrical shape has a more stable physical structure, is not easy to break, and is easy to recycle. It also has a larger specific surface area, which allows for more complete liquid-phase contact and is conducive to fully exerting catalytic activity.
[0019] Preferably, the step 1) is naturally dried before the roasting.
[0020] Preferably, the calcination in step 1) is carried out at 400-600° C. for 3-6 hours, followed by natural cooling.
[0021] The above-mentioned drying and natural cooling can prevent the pores in the catalyst from breaking and ensure the contact area of the catalyst.
[0022] Preferably, the mass fraction of ammonium tungstate in the solution of step 2) is 5%.
[0023] The optimal concentration of ammonium tungstate solution has a better tungsten element distribution effect after impregnation. If the ammonium tungstate concentration is too high, the ion movement speed will be too fast, the element clustering effect will occur, the tungsten element will be concentrated, the dispersion will be poor, and it will not be effectively distributed, thereby reducing the catalytic efficiency.
[0024] Preferably, the drying and calcining in step 4) is drying at 105-220° C. for 1-6 hours, then increasing the temperature to 400-550° C. at 5° C. / min, and calcining for 3-6 hours.
[0025] The above-mentioned heating method combined with the calcination time can effectively prevent the catalyst from pore rupture, increase the porosity, and improve the catalytic effect of the catalyst, thereby reducing the temperature required for the reaction.
[0026] Compared with the prior art, the present invention has the following beneficial effects: three active centers are combined in a specific manner to form a 1-butene catalyst, tungsten element is supported by a solid matrix, the catalyst is easy to regenerate, has high catalytic activity, reduces the reaction activation energy, and thus reduces the temperature required for the dehydration reaction; the raw material conversion rate is high, the 1-butene selectivity is high, the production cost is reduced and the product quality is improved. DETAILED DESCRIPTION
[0027] The present invention will be further described below in conjunction with the embodiments. Embodiments 2, 7, 10, 14 and 17 are the best embodiments of the present invention.
[0028] Using bio-butanol as a raw material and the catalysts prepared in the following examples and comparative examples, the 1-butene preparation process mainly includes: raw material preheating, reaction and separation. The n-butanol raw material is heat-exchanged with the discharge from the bottom of the distillation tower, the n-butanol raw material is heated to 150° C., and then heated to 280° C. in a furnace, and the n-butanol undergoes a dehydration reaction under the action of the catalysts obtained in the examples and comparative examples to generate 1-butene, water, and other isomers of butene. The above mixture enters the distillation tower together with the n-butanol, 1-butene and its isomers are obtained from the top of the tower, and a mixture of butanol and water is obtained in the bottom of the tower. 1-butene and its isomers are separated by distillation to obtain 1-butene.
[0029] In the following preparation methods, the catalysts are prepared by the process of: raw material mixing, extrusion, drying and calcination, solution preparation, pre-impregnation and impregnation, drying and calcination to obtain the renewable 1-butene catalyst.
[0030] Embodiment 1~4
[0031] A renewable 1-butene catalyst and preparation method thereof:
[0032] 1) Pseudo-boehmite, silica, sesbania powder, citric acid and deionized water were mixed uniformly by weight, wherein the mass fractions of sesbania powder, citric acid and deionized water in the five raw materials were 3%, 3% and 9% respectively, and the catalyst shape was controlled to be cylindrical with a diameter of 1 mm and a length of 5 mm. The catalyst was dried at 120° C. for 2 h and calcined at 550° C. for 5 h to obtain a catalyst matrix;
[0033] 2) Dissolve ammonium tungstate in water to make a 5% ammonium tungstate solution, and add dilute hydrochloric acid to adjust the pH of the solution to 3-4;
[0034] 3) The catalyst substrate prepared in step 1) is immersed in deionized water (pre-immersion water) for 15 minutes, and immersed in the ammonium tungstate solution obtained in step 2) for 30 minutes; wherein the weight ratio of the catalyst substrate to the deionized water is 0.5:1, and the mass ratio of the catalyst substrate to the ammonium tungstate solution is 1:3;
[0035] 4) The impregnated solid obtained in step 3) was air-dried for 1 hour, dried at 120°C for 2 hours, and calcined at 450°C for 4 hours, with a volume space velocity of 1 hour -1 , to obtain a regenerable 1-butene catalyst.
[0036] Among them, pseudo-boehmite and silica account for 85% of the mass of the raw materials in the mist. The effect of the mass ratio of pseudo-boehmite to silica on the catalyst activity is shown in Table 1.
[0037] Table 1 Catalytic efficiency of n-butanol dehydration reaction at different mass ratios of pseudo-boehmite and silica
[0038] .
[0039] As shown in Table 1, as the mass ratio of pseudo-boehmite to silica increases, at a suitable silicon-aluminum ratio, after calcination, the catalyst acidity is greater and the corresponding catalyst activity is higher; when the silicon-aluminum ratio is lower or higher, the catalyst acidity is lower and the corresponding catalyst activity is lower. For the above reasons, the conversion of n-butanol first increases and then decreases, the corresponding 1-butene selectivity does not change significantly, and the alkane yield is relatively low.
[0040] Embodiments 5 to 8
[0041] A renewable 1-butene catalyst and a preparation method thereof. Based on the preparation methods of Examples 1 to 4, the mass ratio of pseudo-boehmite to silicon dioxide is set to 3, the calcination temperature in step 1) is shown in Table 2 below, and other conditions are the same as in Examples 1 to 4.
[0042] Table 2 Effect of calcination temperature of catalyst substrate on catalytic efficiency of n-butanol dehydration reaction
[0043] .
[0044] It can be seen from Table 1 that as the calcination temperature gradually increases, the catalyst activity first increases and then decreases, which is mainly related to the effect of temperature on the distribution of B acid and L acid on the catalyst surface.
[0045] Embodiments 9 to 12
[0046] A renewable 1-butene catalyst and a preparation method thereof. Based on the preparation methods of Examples 1 to 4, the mass ratio of pseudo-boehmite to silica is set to 3, the mass ratio of the catalyst substrate used for impregnation in deionized water (pre-impregnation water) in step 3) is shown in Table 3 below, and other conditions are the same as in Examples 1 to 4.
[0047] Table 3 Catalytic efficiency of n-butanol dehydration reaction by mass ratio of catalyst substrate to pre-impregnation water
[0048] .
[0049] It can be seen from Table 3 that with the increase of the mass ratio of the catalyst substrate to the pre-impregnation water, the catalyst activity first increases and then decreases, which is mainly related to the catalyst loading process. Pre-impregnation mainly affects the active component loading process. Pre-impregnation can reduce the adsorption amount of the active component during the impregnation process, thereby affecting the active component loading amount. At the same time, it can affect the distribution of the active component in the carrier, avoiding excessive aggregation or dispersion of tungsten elements into the center of the substrate, thereby affecting the catalyst activity.
[0050] Embodiments 13 to 16
[0051] A regenerable 1-butene catalyst and a preparation method thereof. Based on the preparation methods of Examples 1 to 4, the mass ratio of pseudo-boehmite to silicon dioxide is set to 3, the calcination temperature in step 4) is shown in Table 4 below, and other conditions are the same as in Examples 1 to 4.
[0052] Table 4 Effect of catalyst calcination temperature on catalytic efficiency of n-butanol dehydration reaction
[0053] .
[0054] It can be seen from Table 4 that as the calcination temperature gradually increases, the catalyst activity first increases and then decreases. This is mainly related to the effect of temperature on the distribution of B acid and L acid on the catalyst surface. It also affects the existence form of the W element on the catalyst, thereby affecting the catalyst activity.
[0055] Comparative Examples 1 to 5 and Examples 17 to 19
[0056] A regenerable 1-butene catalyst is prepared according to the methods of Examples 1 to 4, wherein the mass ratio of pseudo-boehmite to silica is set to 3, the calcination temperature in step 4) is as shown in Table 4 below, and other conditions are the same as those in Examples 1 to 4.
[0057] Table 5 Catalytic efficiency of catalyst composition for n-butanol dehydration reaction
[0058] .
[0059] It can be seen from Table 5 that the catalyst composition has a great influence on the catalyst activity. When silicon, aluminum and tungsten oxides are used, the catalyst activity and selectivity are higher.
[0060] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.
Claims
1. A regenerable 1-butene catalyst, characterized in that: By weight: aluminum oxide 30-90%, silicon oxide 5-65%, tungsten oxide 5-30%; The following steps are involved: 1) Pseudo-boehmite, 0.02-0.1 parts of silicon dioxide, 0.02-0.1 parts of sesbania powder and 0.02-0.1 parts of citric acid are uniformly mixed by weight, and calcined to obtain a catalyst matrix; wherein the molar ratio of pseudo-boehmite to silicon dioxide is 2-5:1; 2) Dissolve ammonium tungstate in water to make a solution with a mass fraction of 3-10%, and add dilute hydrochloric acid to adjust the pH of the solution to 3-4; 3) immersing the catalyst substrate prepared in step 1) in deionized water for 5 to 30 minutes and in the solution obtained in step 2) for 5 to 60 minutes; wherein the weight ratio of the catalyst substrate to the deionized water is 0.4 to 1:1, and the mass ratio of the catalyst substrate to the solution is 1:2 to 5; 4) drying the impregnated solid obtained in step 3), drying, and calcining to obtain a regenerable 1-butene catalyst; The calcination in step 1) is performed at 400-600°C for 3-6 hours and then cooled naturally; The drying and calcining in step 4) are drying at 105-220° C. for 1-6 hours, then increasing the temperature to 400-550° C. at a rate of 5° C. / min, and calcining for 3-6 hours.
2. The regenerable 1-butene catalyst according to claim 1, characterized in that: By weight: aluminum oxide 40~70%, silicon oxide 20~55%, tungsten oxide 10~20%.
3. The regenerable 1-butene catalyst according to claim 1, characterized in that: After being evenly mixed in step 1), an extruder is used to extrude the mixture into a cylindrical shape with a diameter of 1.5-3 mm and a length of 20-40 mm.
4. The regenerable 1-butene catalyst according to claim 1, characterized in that: In step 1), the steel is naturally dried before being fired.
5. The regenerable 1-butene catalyst according to claim 1, characterized in that: The solution described in step 2) has a mass fraction of 5% ammonium tungstate.