Efficient preparation method of vanadium catalyst for sulfuric acid production

Abstract

The invention discloses an efficient preparation method of a vanadium catalyst for sulfuric acid production, which comprises the following steps: preparing vanadium water, silica sol suspension and 1 + 1 dilute sulfuric acid solution, and converting the mass of each raw material into volume; the retention time from the time when the raw materials enter the liquid-liquid phase microreactor to the time when the reaction product flows out is controlled to be 5-10 min, the raw materials are injected into the liquid-liquid phase reactor through a constant flow pump, the reaction temperature is 50-60 DEG C, the frequency of a reactor motor is 10-25 Hz, and a vanadium-containing active material is prepared; the vanadium-containing active material and a carrier diatomite are mixed to prepare a pre-forming material, the pre-forming material is subjected to extrusion forming to obtain a vanadium catalyst semi-finished product, and the vanadium catalyst semi-finished product is dried and roasted to obtain a vanadium catalyst finished product. The vanadium catalyst prepared by the invention has the advantages of good dispersity of active components, high catalyst activity, long service life, short time consumption and low energy consumption.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical technology, and specifically relates to a method for efficiently preparing a vanadium catalyst for sulfuric acid production. Background Art

[0003] Vanadium catalyst is an indispensable chemical material in the contact process of sulfuric acid production, and has a history of more than 100 years of use. At present, with the acceleration of my country's industrialization process, the scale and capacity of sulfuric acid production have increased rapidly. At the same time, with the increasing environmental protection requirements, the performance requirements for vanadium catalysts used in sulfuric acid production are also increasing.

[0004] The existing method for preparing vanadium catalysts is to dissolve potassium hydroxide in a reactor with water vapor, add vanadium pentoxide to prepare vanadium water, then add dilute sulfuric acid to neutralize and prepare active materials for catalysts, and then mix and grind with diatomaceous earth, alkali metal sulfate, sulfur powder, etc. to disperse, extrude into strips, dry and roast to finally obtain vanadium catalyst products. Its production process is to prepare active substances in an intermittent reactor through a large dose of liquid-liquid reaction. This process is difficult to effectively control the system temperature due to the heat release of the reaction, and side reactions are prone to occur, resulting in larger active substance nuclei, and subsequent processes are difficult to disperse. In addition, the skeleton and pore structure of diatomaceous earth are easily destroyed during mixing and grinding, resulting in low catalyst porosity, poor air permeability, poor catalytic activity, low thermal stability, and short service life. Summary of the invention

[0006] The purpose of the present invention is to overcome the above disadvantages and provide a vanadium catalyst for sulfuric acid production with good dispersibility of active components, high catalyst activity and long life, short time consumption and low energy consumption.

[0007] The solution adopted by the present invention to solve the technical problem is as follows: The invention discloses a method for efficiently preparing a vanadium catalyst for sulfuric acid production, comprising the following steps: (1) Raw material preparation: Based on the mass of the prepared vanadium catalyst, weigh 3.4-7.9% of potassium hydroxide and 0.7-2.1% of sodium hydroxide by mass of the vanadium catalyst, add 3.5-4 times the total mass of potassium hydroxide and sodium hydroxide in water into a container, slowly add potassium hydroxide and sodium hydroxide while stirring until they are completely dissolved and cooled to room temperature, then add 5.5-8% of vanadium pentoxide by mass of the vanadium catalyst while stirring for 0.5-2 h until the vanadium pentoxide is completely dissolved to obtain vanadium water for use; weigh 3-4.5 times the mass of vanadium pentoxide and fumed silica (the mass ratio of the two is 1:1), mix and stir to disperse into a silica sol suspension for use; 3.7-4.5 times the mass of vanadium pentoxide by volume of 1+1 dilute sulfuric acid solution for use; (2) Raw material density determination: Measure the density of vanadium water, silica sol suspension and 1+1 dilute sulfuric acid solution, and convert the mass of each raw material into volume; (3) Preparation of vanadium-containing materials: The residence time from the time when the raw materials enter the liquid-liquid phase microreactor to the time when the reaction products flow out is controlled at 5-10 min. The flow rates of vanadium water, silica sol suspension, and 1+1 dilute sulfuric acid are determined according to the residence time and injected into the liquid-liquid phase reactor through a constant flow pump. The reaction temperature is 50-60°C and the reactor motor frequency is 10-25 Hz to prepare vanadium-containing active materials. (4) Mixing and molding: Mixing the vanadium-containing active material with the carrier diatomaceous earth to obtain a pre-molding material, and then extruding to obtain a vanadium catalyst semi-finished product; (5) Drying and calcination: The vanadium catalyst semi-finished product is dried and calcined to obtain the vanadium catalyst finished product.

[0008] In the above-mentioned method for efficiently preparing a vanadium catalyst for sulfuric acid production, the mass ratio of the silica sol to the fumed silica in step (1) is 1:1.

[0009] The above-mentioned efficient preparation method of a vanadium catalyst for sulfuric acid production, wherein the mixing method described in step (4) is: transferring the vanadium-containing active material to a trough mixer, adding 65-70% of the mass of the vanadium catalyst carrier diatomaceous earth and stirring and dispersing for 7-15 minutes to obtain the pre-molding material.

[0010] The above-mentioned efficient preparation method of a vanadium catalyst for sulfuric acid production, wherein the drying and calcining method in step (5) is: drying the vanadium catalyst semi-finished product at a temperature of 120-180°C for 1-2 hours, and then calcining it in an oxygen-rich environment at a temperature of 550-630°C for 0.5-1 hour.

[0011] Compared with the prior art, the present invention has obvious beneficial effects. From the above technical scheme, it can be seen that the present invention uses liquid-liquid phase micro-reaction equipment to accurately control the flow rate of reactants and reaction conditions, and controls the reaction temperature within a suitable range, so that the high heat release involved in the reaction of vanadium water and acid is controlled to obtain active substances with suitable particle sizes. The present invention has a fast reaction speed for preparing vanadium-containing materials, uniform material mixing, and stable material composition. The obtained vanadium-containing materials do not have any solid particles, the components are evenly dispersed, and the fluidity is good. The pure liquid vanadium-containing materials are more evenly mixed with diatomite, and no rolling is required. The pore structure of diatomite is retained intact. The finished active components of the prepared vanadium catalyst are evenly dispersed and have high porosity, which improves the activity of the vanadium catalyst and extends the service life of the vanadium catalyst. The preparation process is short in time, low in energy consumption, safe and efficient. According to experimental measurements, compared with the traditional production method, the distribution uniformity of active substances in the vanadium catalyst matrix prepared by this method is higher, the catalytic activity is better, and the catalytic activity decay is small after accelerated aging (treated at 850 ° C for 48 hours). DETAILED DESCRIPTION

[0013] The specific implementation manner and beneficial effects of the efficient preparation method of a vanadium catalyst for sulfuric acid production proposed by the present invention are described in detail below in combination with preferred embodiments.

[0014] Embodiment 1: An efficient preparation method of a vanadium catalyst for sulfuric acid production specifically comprises the following steps: (1) Prepare raw materials: weigh 481.9 g potassium hydroxide and 82.5 g sodium hydroxide, add them to 2000 g water while stirring until they are completely dissolved and cooled to room temperature, then add 306 g vanadium pentoxide while stirring, and react by stirring for 0.5 h until the vanadium pentoxide is completely dissolved to obtain 2850 g vanadium water (a small amount of water evaporates during the reaction, the same below), weigh 405 g silica sol and 405 g fumed silica, mix and stir to disperse into 810 g silica sol suspension, and 1107 g 1+1 sulfuric acid solution by volume; (2) Raw material density determination: The density of vanadium water, silica sol suspension and 1+1 sulfuric acid was measured to be 1.28 g / mL, 1.19 g / mL and 1.50 g / mL respectively. According to the mass of raw materials in step (1), the required vanadium water is 2262.0 mL, silica sol suspension is 680.7 mL and 1+1 dilute sulfuric acid solution is 738 mL; (3) Preparation of vanadium-containing materials: In order to obtain a better particle size of vanadium-containing materials, the residence time from the time the raw materials enter the liquid-liquid phase microreactor to the time the reaction products flow out is controlled at 8 min. The flow rates of vanadium water, silica sol suspension, and 1+1 dilute sulfuric acid are determined to be 230.5 mL / min, 69.4 mL / min, and 75.2 mL / min, respectively, based on the residence time. They are then injected into the liquid-liquid phase reactor through a constant flow pump. The reaction system temperature is 55 °C, and the reactor motor frequency is 20 Hz. Vanadium-containing active materials are prepared. (4) Mixing and molding: The vanadium-containing material of step (3) was transferred to a trough mixer, 3781 g of diatomaceous earth was added, and stirred and dispersed for 7 min to obtain a pre-molding material, which was then extruded to obtain a vanadium catalyst semi-finished product; (5) Drying and calcining: The vanadium catalyst semi-finished product of step (4) is dried at 120°C for 2 h, and then calcined at 630°C in an oxygen-rich environment for 0.5 h to obtain a finished vanadium catalyst.

[0015] According to experimental measurements, compared with traditional production methods, the distribution uniformity of active substances in the vanadium catalyst matrix prepared by this method is higher, the catalytic activity is 93.15%, and the catalytic activity after accelerated aging (treated at 850°C for 48 hours) is 93.02%. The accelerated aging catalytic activity attenuation is small.

[0016] Embodiment 2: An efficient preparation method of a vanadium catalyst for sulfuric acid production specifically comprises the following steps: (1) Prepare raw materials: weigh 565.6 g potassium hydroxide and 119.1 g sodium hydroxide, add them to 1600 g water while stirring until they are completely dissolved and cool to room temperature, then add 331.6 g vanadium pentoxide while stirring, react for 0.5 h until the vanadium pentoxide is completely dissolved to obtain 2581 g vanadium water, weigh 731.25 g silica sol and 731.25 g fumed silica, mix and stir to disperse into 1462.5 g silica sol suspension, and 1292.1 g 1+1 dilute sulfuric acid solution by volume; (2) Determination of raw material density: The density of vanadium water, silica sol suspension and 1+1 sulfuric acid measured in step (1) are 1.30 g / mL, 1.19 g / mL and 1.50 g / mL respectively. According to the mass of each raw material in step (1), 2016.4 mL of vanadium water, 1229.0 mL of silica sol suspension and 861.4 mL of 1+1 dilute sulfuric acid solution are required; (3) Preparation of vanadium-containing materials: In order to obtain a better particle size of vanadium-containing materials, the residence time from the time the raw materials enter the liquid-liquid phase microreactor to the time the reaction products flow out is controlled at 10 min. The flow rates of vanadium water, silica sol suspension, and 1+1 dilute sulfuric acid are determined to be 147.3 mL / min, 89.8 mL / min, and 62.9 mL / min, respectively, based on the residence time. They are then injected into the liquid-liquid phase reactor through a constant flow pump. The reaction system temperature is 50 °C, and the reactor motor frequency is 10 Hz to prepare vanadium-containing active materials. (4) Mixing and molding: The vanadium-containing active material prepared in step (3) was transferred to a trough mixer, 3411.7 g of diatomaceous earth was added and stirred and dispersed for 10 min to obtain a pre-molding material, which was then extruded to obtain a vanadium catalyst semi-finished product; (5) Drying and calcination: The vanadium catalyst semi-finished product of step (4) is dried at 180°C for 0.5 h, and then calcined at 550°C in an oxygen-rich environment for 1 h to obtain a finished vanadium catalyst.

[0017] According to experimental measurements, compared with traditional production methods, the distribution uniformity of active substances in the vanadium catalyst matrix prepared by this method is higher, the catalytic activity is 92.98%, and the catalytic activity after accelerated aging (treated at 850°C for 48 hours) is 92.94%, and the accelerated aging catalytic activity attenuation is small.

[0018] Embodiment 3: An efficient preparation method of a vanadium catalyst for sulfuric acid production specifically comprises the following steps: (1) Prepare raw materials: weigh 656.0 g potassium hydroxide and 160.4 g sodium hydroxide, add them to 1600 g water while stirring until they are completely dissolved and cool to room temperature, then add 357.1 g vanadium pentoxide while stirring, react for 0.5 h with stirring until the vanadium pentoxide is completely dissolved to obtain 2740 g vanadium water, weigh 405 g silica sol and 405 g fumed silica, mix and stir to disperse into 810 g silica sol suspension, and 1107 g 1+1 dilute sulfuric acid solution by volume; (2) Determination of raw material density: The density of the vanadium water, silica sol suspension and 1+1 dilute sulfuric acid measured in step (1) is 1.31 g / mL, 1.19 g / mL and 1.50 g / mL respectively. According to the mass of each raw material in step (1), 2091.6 mL of vanadium water, 1058.8 mL of silica sol suspension and 984.4 mL of 1+1 dilute sulfuric acid solution are required; (3) Preparation of vanadium-containing materials: In order to obtain a better particle size of vanadium-containing materials, the residence time from the time the raw materials enter the liquid-liquid phase microreactor to the time the reaction products flow out is controlled at 5 min. The flow rates of vanadium water, silica sol suspension, and 1+1 dilute sulfuric acid are determined to be 303.5 mL / min, 153.6 mL / min, and 142.8 mL / min, respectively, based on the residence time. They are then injected into the liquid-liquid phase reactor through a constant flow pump. The reaction system temperature is 60 °C, and the reactor motor frequency is 25 Hz to prepare vanadium-containing active materials. (4) Mixing and molding: The vanadium-containing active material prepared in step (3) was transferred to a trough mixer, 3339.5 g of diatomaceous earth was added, and stirred and dispersed for 15 min to obtain a pre-molding material, which was then extruded to obtain a vanadium catalyst semi-finished product; (5) Drying and calcining: The vanadium catalyst semi-finished product of step (4) was dried at 160° C. for 1.5 h, and then calcined at 590° C. in an oxygen-rich environment for 0.8 h to obtain a finished vanadium catalyst.

[0019] According to experimental measurements, compared with traditional production methods, the distribution uniformity of active substances in the vanadium catalyst matrix prepared by this method is higher, the catalytic activity is 93.24%, and the catalytic activity after accelerated aging (treated at 850°C for 48 hours) is 93.10%. The accelerated aging catalytic activity attenuation is small.

[0020] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. 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 falls within the scope of the technical solution of the present invention.

Claims

1. An efficient preparation method of a vanadium catalyst for sulfuric acid production, comprising the following steps: (1) Raw material preparation: Based on the mass of the prepared vanadium catalyst, weigh 3.4-7.9% of potassium hydroxide and 0.7-2.1% of sodium hydroxide in an amount equal to the mass of the vanadium catalyst, add 3.5-4 times the total mass of water of the potassium hydroxide and sodium hydroxide into a container, slowly add the potassium hydroxide and sodium hydroxide while stirring until they are completely dissolved and cooled to room temperature, then add 5.5-8% of vanadium pentoxide in an amount equal to the mass of the vanadium catalyst while stirring for 0.5-2 h until the vanadium pentoxide is completely dissolved to obtain vanadium water for later use; weigh 3-4.5 times the mass of vanadium pentoxide in an amount equal to silica sol and fumed silica (the mass ratio of the two is 1:1), mix and stir to disperse into a silica sol suspension for later use; and 3.7-4.5 times the mass of vanadium pentoxide in an amount equal to 1+1 dilute sulfuric acid solution by volume for later use; (2) Raw material density determination: Measure the density of vanadium water, silica sol suspension and 1+1 dilute sulfuric acid solution, and convert the mass of each raw material into volume; (3) Preparation of vanadium-containing materials: The residence time from the time the raw materials enter the liquid-liquid phase microreactor to the time the reaction products flow out is controlled at 5-10 min. The flow rates of vanadium water, silica sol suspension, and 1+1 dilute sulfuric acid are determined based on the residence time and injected into the liquid-liquid phase reactor through a constant flow pump. The reaction temperature is 50-60 °C and the reactor motor frequency is 10-25 Hz to prepare vanadium-containing active materials. (4) Mixing and molding: Mixing the vanadium-containing active material with the carrier diatomaceous earth to obtain a pre-molding material, and then extruding to obtain a vanadium catalyst semi-finished product; (5) Drying and calcination: The vanadium catalyst semi-finished product is dried and calcined to obtain the vanadium catalyst finished product.

2. The method for efficiently preparing a vanadium catalyst for sulfuric acid production according to claim 1, wherein the mass ratio of the silica sol to the fumed silica in step (1) is 1:

1.

3. A highly efficient preparation method for a vanadium catalyst for sulfuric acid production as claimed in claim 1, wherein the mixing method described in step (4) is: transferring the vanadium-containing active material to a trough mixer, adding 65-70% of the mass of the vanadium catalyst carrier diatomaceous earth, stirring and dispersing for 7-15 minutes, and obtaining a pre-molding material.

4. A highly efficient preparation method for a vanadium catalyst for sulfuric acid production as claimed in claim 1, wherein the drying and calcining method in step (5) is as follows: drying the vanadium catalyst semi-finished product at 120-180°C for 1-2 h, and then calcining it at 550-630°C in an oxygen-rich environment for 0.5-1 h.