阅读说明：本技术 含镧钒催化剂及其制备方法和应用 (lanthanum-containing vanadium catalyst and preparation method and application thereof ) 是由 康勇 王鑫 于 2018-06-10 设计创作，主要内容包括：本发明公开了一种含镧钒催化剂及其制备方法和应用,所述含镧钒催化剂的催化剂原料由以下组分组成：6.0～8.5％V<Sub>2</Sub>O<Sub>5</Sub>,2～15％KOH,3～10％Na<Sub>2</Sub>SO<Sub>4</Sub>,2～16％含镧化合物,0.5～3％造孔剂,余量为硅藻土,所述原料按照以下方法制备：将KOH配成10～40wt％的水溶液,加入V<Sub>2</Sub>O<Sub>5</Sub>混匀得到钒水,调整钒水pH值为2～5,得到胶体沉淀物,再加入含镧化合物和无水硫酸钠混匀,得到混合胶体物；将制得的混合胶体物与硅藻土、造孔剂混合搅拌后,置于超声波发生器中超声负载0.5～1h,再于室温20-30℃下静置2～6h,将所得物料挤压成型,于80～120℃干燥2～3h后,在400～700℃进行焙烧2～6h后,自然冷却至室温20-30℃,得含镧钒催化剂。本发明提高了钒催化剂的低温活性,使得本发明的催化剂在低温区活性高于传统钒催化剂,在中温区活性也优于传统钒催化剂。(the invention discloses a lanthanum-containing vanadium catalyst and a preparation method and application thereof, wherein the catalyst raw material of the lanthanum-containing vanadium catalyst comprises the following components: 6.0-8.5% V 2 O 5 ，2～15％KOH，3～10％Na 2 SO 4 2-16% of a lanthanum-containing compound, 0.5-3% of a pore-forming agent and the balance of diatomite, wherein the raw materials are prepared according to the following method: preparing KOH into 10-40 wt% aqueous solution, and adding V 2 O 5 Uniformly mixing to obtain vanadium water, adjusting the pH value of the vanadium water to 2-5 to obtain colloidal precipitate, adding a lanthanum-containing compound and anhydrous sodium sulfate, and uniformly mixing to obtain a mixed colloidal substance; mixing and stirring the prepared mixed colloidal substance, diatomite and a pore-forming agent, placing the mixture in an ultrasonic generator for ultrasonic loading for 0.5-1 h, standing the mixture for 2-6 h at the room temperature of 20-30 ℃, carrying out extrusion forming on the obtained material, drying the obtained material for 2-3 h at the temperature of 80-120 ℃, roasting the obtained material for 2-6 h at the temperature of 400-700 ℃, and naturally cooling the obtained product to the room temperature of 20-30 ℃ to obtain vanadium containing lanthanumA catalyst. The invention improves the low-temperature activity of the vanadium catalyst, so that the activity of the catalyst is higher than that of the traditional vanadium catalyst in a low-temperature region and is also better than that of the traditional vanadium catalyst in a medium-temperature region.)

1. The lanthanum-containing vanadium catalyst is characterized in that the catalyst raw material consists of the following components: 6.0-8.5% V₂O₅，2～15％KOH，3～10％Na₂SO₄2-16% of lanthanum-containing compound, 0.5-3% of pore-forming agent and the balance of diatomite, wherein KOH and V are₂O₅The molar ratio of (1-7): 1;

the catalyst raw material is prepared according to the following method, step 1, KOH is prepared into 10-40 wt% aqueous solution, and V is slowly added₂O₅Uniformly mixing to obtain vanadium water, adjusting the pH value of the vanadium water to 2-5 by using acid to obtain colloidal precipitate, adding a lanthanum-containing compound and anhydrous sodium sulfate, and uniformly mixing to obtain a mixed colloidal substance;

and 2, mixing and stirring the mixed colloidal substance prepared in the step 1, diatomite and a pore-forming agent, placing the mixture in an ultrasonic generator for ultrasonic loading for 0.5-1 h, standing the mixture at the room temperature of 20-30 ℃ for 2-6 h, carrying out extrusion forming on the obtained material, drying the obtained material at the temperature of 80-120 ℃ for 2-3 h, heating the obtained material to 400-700 ℃ at the speed of 1-5 ℃/s from the temperature of 20-30 ℃ for roasting, carrying out roasting for 2-6 h, and naturally cooling the obtained product to the room temperature of 20-30 ℃ to obtain the lanthanum-containing vanadium catalyst.

2. The lanthanum containing vanadium catalyst of claim 1, wherein the lanthanum containing vanadium catalyst has a surface area of 3.5 to 4.5m²per g, pore volume of 1.0-1.5X 10^-2cm³(ii)/g, pore size distribution in the range of 90-150nm is 21-28%.

3. The lanthanum containing vanadium catalyst of claim 1, wherein the lanthanum containing compound is lanthanum oxide, lanthanum chloride, or lanthanum nitrate.

4. The lanthanum-containing vanadium catalyst of claim 1, wherein the pore-forming agent is sulfur powder, carbon powder, polyethylene glycol or polyvinyl alcohol.

5. The lanthanum-containing vanadium catalyst according to claim 1, wherein the atmosphere of calcination in step 2 is an oxygen-rich atmosphere or a mixed atmosphere of sulfur dioxide and air.

6. Use of a catalyst feedstock in the preparation of a lanthanum containing vanadium catalyst according to any one of claims 1 to 5, characterized in that the catalyst feedstock consists of: 6.0-8.5% V₂O₅，2～15％KOH，3～10％Na₂SO₄2-16% of lanthanum-containing compound, 0.5-3% of pore-forming agent and the balance of diatomite, wherein KOH and V are₂O₅The molar ratio of (1-7): 1.

7. The use of the lanthanum-containing vanadium catalyst of any one of claims 1 to 5 in the production of sulfuric acid by oxidation of sulfur dioxide, wherein the catalytic temperature is 350 ℃ to 470 ℃ under atmospheric pressure, and the lanthanum-containing vanadium catalyst catalyzes SO₂Conversion ratio of SO catalyzed by vanadium catalyst₂The conversion rate is 12-20%, wherein the vanadium catalyst consists of the following components: 6.0-8.5% V₂O₅，2～15％KOH，3～10％Na₂SO₄0.5-3% of pore-forming agent, and the balance of diatomite, wherein the KOH and the V are₂O₅The molar ratio of (1-7): 1, and the manufacturing process of the vanadium catalyst is the same as that of the lanthanum vanadium catalyst.

8. The use of claim 7, wherein SO is catalyzed by the lanthanum vanadium-containing catalyst at a temperature of from 350 ℃ to 420 ℃₂To SO catalyzed by said vanadium catalyst₂The conversion rate of the catalyst is 12 to 18 percent;

SO is catalyzed by the lanthanum-containing vanadium catalyst at the temperature of 420-440 DEG C₂To SO catalyzed by said vanadium catalyst₂The conversion rate of (A) is 18-21%.

9. The use according to claim 7 or 8,The method is characterized in that the lanthanum-containing vanadium catalyst is placed in a jacketed single-tube reactor, the loading amount of the lanthanum-containing vanadium catalyst and the vanadium catalyst is 30ml, the catalyst granularity is 6-6.5 mm, and the catalyst is used at a space velocity of 3600h^-1inlet air, inlet SO₂10 + -1% by volume, the remainder being air intake.

10. the application of the lanthanum-containing compound in preparing the vanadium catalyst for catalyzing sulfur dioxide is characterized in that the lanthanum-containing compound is lanthanum oxide, lanthanum chloride or lanthanum nitrate, and the mass percentage of the lanthanum-containing compound in the vanadium catalyst is 2-16%.

Technical Field

the invention relates to the technical field of chemical industry, in particular to a lanthanum-containing vanadium catalyst and a preparation method and application thereof.

Background

Sulfuric acid is an important chemical raw material, and the production level of the sulfuric acid is regarded as a reflected benchmark of national industrial strength. At present, industrial sulfuric acid is basically produced by a contact method, and a catalyst for sulfur dioxide oxidation is the core of the production of the sulfuric acid by the contact method. Since the 60's of the 20 th century, the sulfuric acid industry employed vanadium catalysts that had vanadium pentoxide as the major active component. The main chemical components of the vanadium catalyst are vanadium pentoxide (main catalyst), potassium sulfate (or part of sodium sulfate), silica carrier (usually diatomite or oxide with small amount of added aluminium, calcium or magnesium), commonly called vanadium-potassium (sodium) -silicon system catalyst, which has both medium-temperature type and low-temperature type. The medium-temperature catalyst is suitable for 420-600 ℃, and the low-temperature catalyst is suitable for 390-440 ℃. The former has good high temperature activity but poor low temperature activity, and the latter has good low temperature activity but poor high temperature activity. In the production process of the two-rotation and two-absorption sulfuric acid, the two are combined to achieve higher effect.

At present, the domestic medium-temperature vanadium catalyst is prepared by adopting a mixed grinding process, the framework structure of diatomite is greatly damaged, active components are unevenly distributed on the diatomite, and in addition, an active component V is added₂O₅The catalyst is easy to inactivate under high temperature for a long time, the operation cost is high, and the production and the application of the medium-temperature vanadium catalyst are greatly limited.

Disclosure of Invention

The invention aims to provide a lanthanum-containing vanadium catalyst aiming at the problem that the conversion rate of sulfur dioxide in the catalyst under the conditions of medium temperature and low temperature in the prior art cannot be considered at the same time.

The invention also aims to provide a preparation method of the lanthanum-containing vanadium catalyst, which is used for preparing the lanthanum-containing vanadium catalyst with optimal performance by optimizing parameters.

The invention also aims to provide application of the lanthanum-containing vanadium catalyst in the industrial production of sulfuric acid by oxidizing sulfur dioxide so as to improve the conversion rate of the sulfur dioxide.

The technical scheme adopted for realizing the purpose of the invention is as follows:

A catalyst containing lanthanum and vanadium comprises the following raw materials: 6.0-8.5% V₂O₅，2～15％KOH，3～10％Na₂SO₄2 to 16 percent of lanthanum-containing compound, 0.5 to 3 percent of pore-forming agent and the balance of diatomite,Wherein the KOH and V₂O₅The molar ratio of (1-7): 1, the raw materials are prepared according to the following method:

Step 1, preparing KOH into 10-40 wt% aqueous solution, and slowly adding V₂O₅Uniformly mixing to obtain vanadium water, adjusting the pH value of the vanadium water to 2-5 by using acid to obtain colloidal precipitate, adding a lanthanum-containing compound and anhydrous sodium sulfate, and uniformly mixing to obtain a mixed colloidal substance;

And 2, mixing and stirring the mixed colloidal substance prepared in the step 1, diatomite and a pore-forming agent, placing the mixture in an ultrasonic generator for ultrasonic loading for 0.5-1 h, standing the mixture at the room temperature of 20-30 ℃ for 2-6 h, carrying out extrusion forming on the obtained material, drying the obtained material at the temperature of 80-120 ℃ for 2-3 h, heating the obtained material to 400-700 ℃ at the speed of 1-5 ℃/s from the temperature of 20-30 ℃ for roasting, carrying out roasting for 2-6 h, and naturally cooling the obtained product to the room temperature of 20-30 ℃ to obtain the lanthanum-containing vanadium catalyst.

In the technical scheme, the surface area of the lanthanum-containing vanadium catalyst is 3.5-4.5m²The pore volume of the lanthanum-containing vanadium catalyst is 1.0-1.5 multiplied by 10^-2cm³/g。

in the above technical scheme, the lanthanum-containing compound is lanthanum oxide, lanthanum chloride or lanthanum nitrate.

in the technical scheme, the pore-forming agent is sulfur powder, carbon powder, polyethylene glycol or polyvinyl alcohol.

In the technical scheme, the kieselguhr is Sealite kieselguhr or first-grade kieselguhr.

In the technical scheme, the diatomite in the step 2 is prepared into refined diatomite through high-temperature calcination, acid treatment, suction filtration and drying, the acid adopted in the acid treatment is sulfuric acid, the mass concentration of the sulfuric acid is 10-80%, the acid treatment time is 0.5-5 h, and the acid treatment temperature is 40-100 ℃.

In the above technical scheme, the roasting atmosphere in the step 2 is an oxygen-rich atmosphere or a mixed atmosphere of sulfur dioxide and air.

In another aspect of the invention, the invention also comprises the application of a catalyst raw material in the preparation of the lanthanum-containing vanadium catalyst, wherein the catalyst raw material is prepared from the following componentsThe composition is as follows: 6.0-8.5% V₂O₅，2～15％KOH，3～10％Na₂SO₄2-16% of lanthanum-containing compound, 0.5-3% of pore-forming agent and the balance of diatomite, wherein KOH and V are₂O₅The molar ratio of (1-7): 1.

On the other hand, the invention also comprises the application of the lanthanum-vanadium-containing catalyst in the production of sulfuric acid by oxidizing sulfur dioxide, wherein the catalytic temperature is 350-470 ℃ under the normal pressure condition, and SO is catalyzed by the lanthanum-vanadium-containing catalyst₂Conversion ratio of SO catalyzed by vanadium catalyst₂The conversion rate is 12-20%, wherein the vanadium catalyst consists of the following components: 6.0-8.5% V₂O₅，2～15％KOH，3～10％Na₂SO₄0.5-3% of pore-forming agent, and the balance of diatomite, wherein the KOH and the V are₂O₅The molar ratio of (1-7): 1, and the manufacturing process of the vanadium catalyst is the same as that of the lanthanum vanadium catalyst.

in the technical scheme, SO is catalyzed by the lanthanum-containing vanadium catalyst at 350-420 DEG C₂To SO catalyzed by said vanadium catalyst₂The conversion rate of the catalyst is 12 to 18 percent;

SO is catalyzed by the lanthanum-containing vanadium catalyst at the temperature of 420-440 DEG C₂To SO catalyzed by said vanadium catalyst₂The conversion rate of (A) is 18-21%.

In the technical scheme, the lanthanum-containing vanadium catalyst is placed in a jacketed single-tube reactor, the loading amount of the lanthanum-containing vanadium catalyst and the vanadium catalyst is 30ml, the catalyst granularity is 6-6.5 mm, and the space velocity is 3600h^-1Inlet air, inlet SO₂10 + -1% by volume, the remainder being air intake.

The application of the lanthanum-containing compound in preparing the vanadium catalyst for catalyzing sulfur dioxide is that the lanthanum-containing compound is lanthanum oxide, lanthanum chloride or lanthanum nitrate, and the mass percentage of the lanthanum-containing compound in the vanadium catalyst is 2-16%.

Compared with the prior art, the invention has the beneficial effects that:

According to the invention, the lanthanum-containing oxide is added into the catalyst, so that the low-temperature activity of the vanadium catalyst is improved, the activity of the catalyst in a low-temperature region is higher than that of the traditional vanadium catalyst, and the activity of the catalyst in a medium-temperature region is also better than that of the traditional vanadium catalyst, so that the catalyst has a wider use temperature range, is suitable for low-temperature and medium-temperature environments, and is suitable for any part of a converter of a sulfuric acid production device. Compared with the traditional catalyst, the catalyst prepared by the invention has higher activity and thermal stability, has better low-temperature catalytic performance than the traditional lanthanum-containing vanadium catalyst, and can meet the requirement of higher total conversion rate.

Drawings

FIG. 1 is an SEM image of the catalysts obtained in examples 1-3 and comparative examples 1-2, wherein: a is an SEM picture of the lanthanum-containing vanadium catalyst obtained in example 1, b is an SEM picture of the lanthanum-containing vanadium catalyst obtained in example 2, c is an SEM picture of the lanthanum-containing vanadium catalyst obtained in example 3, d is an SEM picture of the vanadium catalyst obtained in comparative example 1, and e is an SEM picture of the lanthanum-containing vanadium catalyst obtained in comparative example 2.

FIG. 2 is a Mapping chart of the elements of the lanthanum-containing vanadium catalyst obtained in example 3.

Fig. 3 is a Mapping chart of each element of the vanadium catalyst obtained in comparative example 1.

FIG. 4 is an adsorption curve of the catalysts obtained in examples 1 to 3 and comparative examples 1 to 2.

FIG. 5 is a graph showing pore size distributions of catalysts obtained in examples 1 to 3 and comparative examples 1 to 2.

Detailed Description

The invention is described in further detail below with reference to the figures and specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.