CN110624570A

CN110624570A - Preparation method of low-temperature catalyst for preparing vanadium sulfate by wet conversion

Info

Publication number: CN110624570A
Application number: CN201810660261.4A
Authority: CN
Inventors: 孙远龙; 袁浩然; 吴结华; 张觅
Original assignee: China Petrochemical Corp; Research Institute of Sinopec Nanjing Chemical Industry Co Ltd
Current assignee: China Petrochemical Corp; Research Institute of Sinopec Nanjing Chemical Industry Co Ltd
Priority date: 2018-06-25
Filing date: 2018-06-25
Publication date: 2019-12-31
Anticipated expiration: 2038-06-25
Also published as: CN110624570B

Abstract

The invention belongs to the technical field of catalysts, and particularly relates to a preparation method of a catalyst for preparing vanadium sulfate by low-temperature wet conversion. A process for preparing vanadium sulfate catalyst by low-temp wet conversion includes such steps as adding silica sol, alkali metal sulfate, assistant and refined diatomite, mixing, rolling, extruding, drying and calcining. The catalyst prepared by the method has the characteristics of pulverization resistance, high strength, good activity stability and the like.

Description

Preparation method of low-temperature catalyst for preparing vanadium sulfate by wet conversion

Technical Field

The present invention relates to a method for producing a catalyst. In particular to a preparation method of a catalyst for preparing vanadium sulfate by low-temperature wet conversion.

Background

The wet contact method for preparing acid is to catalytically convert sulfur dioxide into sulfur trioxide in the presence of water vapor without washing and drying, and the sulfur dioxide is directly condensed into acid. Obviously, the wet contact method for preparing acid is simpler in process and more beneficial to recycling of system energy. Most hydrogen sulfide sources are relatively clean, so the wet contact method acid preparation process is widely applied. The wet acid making process is the most economical choice. Meanwhile, in many cases, sulfur is not a product required by users, hydrogen sulfide is an attractive option for preparing acid, and a plurality of process procedures can be omitted by using hydrogen sulfide for preparing acid, so that the investment and the production cost are reduced, and the product has stronger market competitiveness.

In the prior art, the production process flow of the domestic catalyst for preparing sulfuric acid by oxidizing sulfur dioxide comprises the following steps: refining diatomite; dissolving vanadium pentoxide, alkali metal mother liquor and other auxiliary agents; neutralizing with sulfuric acid; the neutralized substance is mixed with refined diatomite and other assistants, and then the mixture is formed, dried and calcined.

The wet conversion process for preparing acid from hydrogen sulfide features that the raw material gas contains lots of water vapour. The catalytic oxidation of sulfur dioxide is carried out under conditions that contain a large amount of water vapor. The catalyst prepared by the prior art cannot meet the wet process, the traditional vanadium-silicon catalyst is seriously pulverized, and the pressure drop is increased after the catalyst is used for a period of time. And the import operation temperature of the catalyst for preparing acid by the domestic wet contact method is generally between 410 and 420 ℃. However, as the environmental protection requirements become more stringent, the catalyst is required to have better low-temperature activity.

Disclosure of Invention

The invention aims to provide a preparation method of a catalyst for preparing vanadium sulfate by low-temperature wet conversion. The catalyst prepared by the method has the advantages of pulverization resistance, high strength, good low-temperature activity and good stability.

The invention relates to a preparation method of a vanadium sulfate catalyst by low-temperature wet conversion, which is characterized in that silica sol is added when preparing an active phase of the catalyst, then the active phase of the catalyst is uniformly mixed with alkali metal sulfate, an auxiliary agent and refined diatomite, and the mixture is rolled, compacted and extruded, dried, roasted and the like to prepare a finished catalyst product.

Preferably, the average particle diameter of the colloidal particles of the silica sol solution is 5 nm ~ 50nm, and the pH value is 8 ~ 11.

SiO in the silica sol₂The content of the catalyst accounts for 5 ~ 10 percent of the mass of the catalyst.

The silica sol is JA or JN type silica sol.

The auxiliary agent is methyl cellulose.

The roasting temperature is 450 ℃, ~ 500 ℃ and N is introduced₂Calcining for 30 ~ 40 min, and introducing SO₂The roasting time is 40 ~ 50, and finally air is introduced at 600 ℃ of ~ 650 ℃ and 650 ℃ to roast for 50 ~ 60 minutes.

SO during the roasting₂The content was 6 ~ 9%.

The catalyst prepared by the method has the advantages of pulverization resistance, high strength, good activity stability and the like.

Detailed Description

The present invention will be further described with reference to the following examples.

Example 1

V₂O₅ 6.5%, K₂O/V₂O₅2.66 (molar ratio) sodium sulfate 8%, Cesium sulfate 2%, P₂O₅1.5 percent of methyl cellulose, and the balance of diatomite. Dissolving KOH with steam, and mixing with V₂O₅Prepared under the condition of hot boiling, K₂O/V₂O₅KVO of 2.66₃Mixed with KOH to prepare a solution (hereinafter referred to as vanadium solution) of 265.9g/l, K/V = 2.66. Then 6.64g of 50% CsOH and 12g of Na were added₂CO₃Adding 45g of jN25 type silica sol into 48.9 vanadium water, neutralizing with 1:1 sulfuric acid, controlling pH value between 2 and 3, adding colloidal precipitate, 3g of phosphoric acid, 2g of methylcellulose, 160.8g of diatomite and the like into a roller, uniformly mixing, adding water, tightly rolling to obtain a plastic material, extruding, drying, roasting, introducing N at 450 DEG C₂Roasting for 40 min, and introducing 6% SO₂The calcination time is 40 minutes, and finally air is introduced at 600 ℃ for calcination for 60 minutes, so that 200g of the catalyst is prepared. The process was repeated to prepare 200g of a catalyst.

Example 2

V₂O₅ 6.5%, K₂O/V₂O₅2.66 (molar ratio), sodium sulfate 6.0%, cesium sulfate 4%, P₂O₅1.5 percent of methyl cellulose, and the balance of diatomite. Dissolving KOH with steamIs transformed into and is combined with V₂O₅KVO with K/V of 2.66 prepared under the condition of hot boiling₃Mixed with KOH to prepare a solution (hereinafter referred to as vanadium solution) of 265.9g/l, K/V = 2.66. Then 13.26g of 50% CsOH, 9gNa₂CO₃Adding 40g of jN25 type silica sol into 48.9 vanadium water, neutralizing with 1:1 sulfuric acid, controlling pH value between 2 and 3 to obtain colloidal precipitate, adding 3g of phosphoric acid, 2g of methylcellulose, 150.8g of diatomite and the like into a roller, uniformly mixing, adding water, tightly rolling to obtain a plastic material, extruding, drying, roasting, introducing N at 450 DEG C₂Roasting for 30 min, and introducing 7% SO₂The calcination time is 50 minutes, and finally air is introduced at 600 ℃ for calcination for 60 minutes, so that 200g of the catalyst is prepared.

Example 3

V₂O₅ 6.5%, K₂O/V₂O₅2.66 (molar ratio) sodium sulfate 2.0%, Cesium sulfate 8%, P₂O₅1.5 percent of methyl cellulose, and the balance of diatomite. Dissolving KOH with steam, and mixing with V₂O₅Prepared under the condition of hot boiling, K₂O/V₂O₅KVO of 2.66₃Mixed with KOH (vanadium solution) to prepare the vanadium solution of 265.9g/l, K₂O/V₂O₅= 2.66. Then 26.52g of 50% CsOH and 3g of Na were added₂CO₃Adding 40g of jN25 type silica sol into 48.9 vanadium water, neutralizing with 1:1 sulfuric acid, controlling pH value between 2 and 3 to obtain colloidal precipitate, adding 3g of phosphoric acid, 2g of methylcellulose, 160.8g of diatomite and the like into a roller, uniformly mixing, adding water, tightly rolling to obtain a plastic material, extruding, drying, roasting, introducing N at 450 DEG C₂Roasting for 30 min, and introducing 6% SO₂The calcination time is 50 minutes, and finally air is introduced at 600 ℃ for calcination for 60 minutes, and the like to prepare 200g of the catalyst. 200g of catalyst was obtained.

Example 4

V₂O₅ 7%, K₂O/V₂O₅3.0 (molar ratio) sodium sulfate 2.0%, Cesium sulfate 8%, P₂O₅1.5 percent of methyl cellulose, and the balance of diatomite. Dissolving KOH with steam, and mixing with V₂O₅Prepared under the condition of hot boiling, K₂O/V₂O₅KVO of 3.0₃Mixed with KOH (vanadium solution) to prepare the vanadium solution of 265.9g/l, K₂O/V₂O₅= 3.0. Then 26.52g of 50% CsOH and 3g of Na were added₂CO₃Adding 45g jN25 type silica sol into 52.6ml vanadium water, neutralizing with 1:1 sulfuric acid to control pH value between 2-3 to obtain colloidal precipitate, adding 3g phosphoric acid, 2g methylcellulose and 147g diatomite into the colloidal precipitate, mixing, adding water, grinding tightly to obtain plastic material, extruding, drying, and calcining while introducing N at 450 deg.C₂Roasting for 30 min, and introducing 8% SO₂The calcination time is 50 minutes, and finally air is introduced at 600 ℃ for calcination for 60 minutes, so that 200g of the catalyst is prepared.

Example 5

V₂O₅ 7.9%, K₂O/V₂O₅3.0 (molar ratio) sodium sulfate 2.0%, cesium sulfate 8%, methyl cellulose 1%, and the balance diatomaceous earth. Dissolving KOH with steam, and mixing with V₂O₅Prepared under the condition of hot boiling, K₂O/V₂O₅KVO of 3.0₃The resulting mixed solution with KOH (hereinafter referred to as vanadium solution) produced 265.9g/l of vanadium solution with K/V = 3.0. Then 26.52g of 50% CsOH and 3g of Na were added₂CO₃Adding 60g of jA25 type silica sol into 59.4ml of vanadium water, neutralizing with 1:1 sulfuric acid to control pH value between 2 and 3 to obtain colloidal precipitate, mixing the colloidal precipitate with 3g of phosphoric acid and 2g of methyl cellulose

Mixing vitamin and 131.5g diatomaceous earth, adding water, grinding tightly to obtain plastic material, extruding, drying, and roasting at 450 deg.C while introducing N₂Roasting for 30 min, and introducing 7% SO₂The calcination time is 50 minutes, and finally air is introduced at 600 ℃ for calcination for 60 minutes, so that 200g of the catalyst is prepared.

Example 6

V₂O₅ 7.9%, K₂O/V₂O₅3.2 (molar ratio) sodium sulfate 2.0%, cesium sulfate 8%, methyl cellulose 1%, and the balance diatomaceous earth. Dissolving KOH with steam, and mixing with V₂O₅Prepared under the condition of hot boiling, K₂O/V₂O₅KVO of 3.2₃Mixed with KOH (vanadium solution) to prepare the vanadium solution of 265.9g/l, K₂O/V₂O₅= 3.2. Then 26.52g of 50% CsOH and 3g of Na were added₂CO₃Adding 80g of JA25 type silica sol into 59.4ml of vanadium water, neutralizing with 1:1 sulfuric acid to control the pH value to be 2-3 to obtain colloidal precipitate, adding 3g of phosphoric acid, 2g of methylcellulose, 125g of diatomite and the like into a mill, uniformly mixing, adding water, tightly rolling to obtain a plastic material, extruding, drying, roasting, introducing N at 450 ℃ and adding₂Roasting for 30 min, and introducing 7% SO₂The calcination time is 50 minutes, and finally air is introduced at 600 ℃ for calcination for 60 minutes, and the like to prepare 200g of the catalyst.

Example 7

V₂O₅ 8.2%, K₂O/V₂O₅3.2 (molar ratio) sodium sulfate 2.0%, cesium sulfate 8%, methyl cellulose 1%, and the balance diatomaceous earth. Dissolving KOH with steam, and mixing with V₂O₅Prepared under the condition of hot boiling, K₂O/V₂O₅KVO of 3.2₃Mixed with KOH (vanadium solution) to prepare the vanadium solution of 265.9g/l, K₂O/V₂O₅= 3.2. Then 26.52g of 50% CsOH and 3g of Na were added₂CO₃Adding 80g of JA25 type silica sol into 59.4ml of vanadium water, neutralizing with 1:1 sulfuric acid to control the pH value to be 2-3 to obtain colloidal precipitate, adding 3g of phosphoric acid, 2g of methylcellulose, 125g of diatomite and the like into a mill, uniformly mixing, adding water, tightly rolling to obtain a plastic material, extruding, drying, roasting, introducing N at 450 ℃ and adding₂Roasting for 30 min, and introducing 9% SO₂The calcination time is 50 minutes, and finally air is introduced at 600 ℃ for calcination for 50 minutes, and the like to prepare 200g of the catalyst.

Sample testing

Catalyst sample: the particle size is psi 9X 3.5X (10-15) mm

Activity test conditions:

the conversion adopts a jacketed single-tube reactor, the tube diameter phi of the single-tube reactor is 36 multiplied by 2.0mm, a temperature thermocouple sleeve is positioned in the center of the converter, and the tube diameter phi of the single-tube reactor is 8 multiplied by 1.5 mm;

loading of the catalyst: 30ml of

The particle size of the catalyst is as follows: 3.35-4 mm

Space velocity: 3600h-1

Inlet SO₂10 percent +/-1 percent of the total volume, about 10 percent of water vapor and the balance of air

System pressure: atmospheric pressure

Temperature of activity detection: 380 deg.C, 410 deg.C

Heat resistance temperature: 600 ℃ for 5h

With SO₂The conversion rate indicates the activity.

Strength test

Catalyst sample having a particle size of ψ 9X 3.5X (10 ~ 15) mm

Strength test conditions:

the method for measuring the radial compressive strength of the particles is carried out according to the regulation of GB/T3635. The strength measurement adopts an intelligent particle strength tester, the precision is 1 grade, and the measuring range is 0-250N.

Acid blister strength test conditions

The sample particles were mixed in a 1: 1H₂SO₄After soaking for 24h, the acid liquor is sucked dry and the determination is carried out according to the strength test conditions.

Abrasion Rate test

According to the specification HG/T2969, wherein the sample is at (120)+5) Drying at deg.C for 2 hr.

The results of the activity test are shown in Table 1, and the results of the strength test are shown in Table 2.

Table 1: results of Activity test

Table 2: test results of Strength and abrasion Rate

Sample examples	Strength (N/cm)	Acid soak Strength (N/cm)	Rate of wear
				Example 1	72．0	63.5	1
Example 2	70.2	60.6	1.3
				Example 3	81．0	70	2
Example 4	83.4	72.1	1.4
				Example 5	86．7	74	2.2
Example 6	90．4	78.6	0.8
				Example 7	85	72．6	1.1
Industry Standard	≧35	---------	≦5

The test results in table 1 show that the low-temperature activity of the catalyst for preparing vanadium sulfate by low-temperature wet conversion prepared by the method is obviously higher than that of the conventional catalyst by wet method, and the test results in table 2 show that the catalyst for preparing vanadium sulfate by low-temperature wet conversion prepared by the method has higher strength and low abrasion rate. Therefore, the catalyst prepared by the method has obviously improved performance and can meet the requirement of higher SO in acid preparation by a wet method₂The conversion rate is required. The catalyst prepared by the method has the advantages of pulverization resistance, high strength, good low-temperature activity and good stability.

Claims

1. A process for preparing vanadium sulfate catalyst by low-temp wet conversion includes such steps as adding silica sol, mixing with alkali metal sulfate, assistant and refined diatomite, rolling, extruding, drying and calcining.

2. The process for preparing a catalyst according to claim 1, wherein the silica sol solution has a mean particle size of 5 nm ~ 50nm and a pH of 8 ~ 11.

3. The process for preparing a catalyst according to claim 1, wherein the silica sol is a JA or JN type silica sol.

4. The process for preparing the catalyst according to claim 1, wherein SiO in the silica sol₂The content of the catalyst accounts for 5 ~ 10 percent of the mass of the catalyst.

5. The process for preparing a catalyst according to claim 1, wherein the auxiliary agent is methylcellulose.

6. The process for preparing the catalyst of claim 1, wherein the calcination temperature is 450 ℃ and ~ 500 ℃ and N is introduced thereinto₂Calcining for 30 ~ 40 min, and introducing SO₂The roasting time is 40 ~ 50 minutes, and finally air is introduced at 600 ℃ of ~ 650 ℃ for 50 ~ 60 minutes.

7. The method of claim 6, wherein SO is present during calcination₂The content was 6 ~ 9%.