A composite desulfurizer suitable for desulfurization under oxygen-containing conditions, a preparation method and application thereof

Abstract

The application discloses a kind of composite desulfurizer suitable for oxygen-containing condition desulfurization and its preparation method and application, belong to desulfurizer technical field.The composite desulfurizer is double-layer composite structure;Wherein: outer layer is iron oxide hydroxyl layer, including iron oxide hydroxyl and first binder;Inner layer is copper zinc aluminum layer, including copper oxide, zinc oxide, alumina and second binder.The composite desulfurizer obtained in the application significantly improves the service life of desulfurizer under oxygen-containing condition, and the sulfur capacity of desulfurizer can be as high as 10~20%, and the simultaneous removal of organic sulfur and inorganic sulfur can be realized in one step, effectively reducing the desulfurization cost, with important application prospect.In addition, the preparation of double-layer structure composite desulfurizer is realized by double-layer extruding machine in the application, and the process is simple, which is beneficial to industrialized mass production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of desulfurizer, and particularly relates to a composite desulfurizer suitable for desulfurization under oxygen-containing conditions and a preparation method and application thereof. BACKGROUND

[0002] In chemical production, hydrogen sulfide and organic sulfur are often contained in gas. The organic sulfur generally refers to carbonyl sulfur and carbon disulfide. These sulfur-containing compounds are toxic or harmful to catalysts or affect product quality, such as causing product color to turn yellow. In addition, organic sulfur is more difficult to remove than hydrogen sulfide. Meanwhile, in the production process of gas, oxygen as a gasification agent will have a small amount of oxygen residue. For example, coke oven gas contains about 0.3-0.8% oxygen, and oxygen content in semi-coke gas is about 0.5%.

[0003] The prior art generally adopts a method of first removing hydrogen sulfide, then hydrolyzing organic sulfur into hydrogen sulfide, and finally removing hydrogen sulfide. For example, patent CN92105197.2 adopts an organic sulfur hydrolysis catalyst of an alkali metal supported on alumina to hydrolyze COS into hydrogen sulfide and then remove the hydrogen sulfide. However, under the condition of oxygen, hydrogen sulfide will be oxidized into active sulfur on the surface of the hydrolysis catalyst, and the active sulfur will be oxidized into sulfurous acid, and the sulfurous acid will be further oxidized into sulfuric acid. This will cause the hydrolysis catalyst of organic sulfur to be sulfated and lose the alkali active center, thereby being poisoned and deactivated, resulting in poor desulfurization effect and long process. There is also a method of high-temperature hydrogenation to first convert organic sulfur into hydrogen sulfide, and then remove it with zinc oxide, such as patent CN202310970924.3. However, high-temperature hydrogenation has high energy consumption, and the oxygen in the gas also consumes valuable hydrogen and easily causes the catalyst bed to overheat. There is also a copper-nickel desulfurizer to remove hydrogen sulfide and organic sulfur at one time, but the simultaneous removal of hydrogen sulfide and organic sulfur has poor effect, low sulfur capacity, and high cost. Therefore, it is necessary to develop a desulfurizer with good desulfurization effect and suitable for desulfurization under oxygen-containing conditions. SUMMARY

[0004] The present application aims to provide a composite desulfurizer suitable for desulfurization under oxygen-containing conditions and a preparation method and application thereof. The composite desulfurizer significantly improves the service life of the desulfurizer under oxygen-containing conditions, has high sulfur capacity, and can simultaneously remove organic sulfur and inorganic sulfur at one time, effectively reduces the desulfurization cost, and has important application prospects.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] The present application provides a composite desulfurizer suitable for desulfurization under oxygen-containing conditions, which is a double-layer composite structure. The outer layer is a hydroxyl iron oxide layer, which comprises hydroxyl iron oxide and a first binder. The inner layer is a copper-zinc-aluminum layer, which comprises copper oxide, zinc oxide, aluminum oxide, and a second binder.

[0007] According to the above scheme, in the inner layer, the mass ratio of copper oxide, zinc oxide and aluminum oxide is 5-10:20-50:30-70.

[0008] According to the above scheme, in the outer layer, the mass ratio of hydroxyl iron oxide and the first binder is 5-9:1.

[0009] According to the above scheme, in the inner layer, the mass ratio of the total mass of copper oxide, zinc oxide and aluminum oxide to the second binder is 4-8:1.

[0010] According to the above scheme, the first binder and the second binder are independently selected from at least one of bentonite, clay, carboxymethyl cellulose (CMC).

[0011] According to the above scheme, the mass ratio of hydroxyl iron oxide in the outer layer to the total mass of copper oxide, zinc oxide and aluminum oxide in the inner layer is 1:1-3.

[0012] A preparation method of the above-mentioned composite desulfurizer suitable for desulfurization under oxygen-containing conditions is provided, comprising the following steps:

[0013] 1) The hydroxyl iron oxide raw material is crushed and sieved to obtain a hydroxyl iron oxide fine powder, then mixed with the first binder, water is added and kneaded to obtain a hydroxyl iron oxide wet strip;

[0014] 2) The copper oxide, zinc oxide and aluminum oxide powders are sieved and mixed to obtain a mixture, then mixed with the second binder, water is added and kneaded to obtain a copper-zinc-aluminum wet strip;

[0015] 3) The kneaded hydroxyl iron oxide wet strip obtained in step 1) and the copper-zinc-aluminum wet strip obtained in step 2) are put into a double-layer extruder to obtain a wet strip with the hydroxyl iron oxide layer as the outer layer and the copper-zinc-aluminum layer as the inner layer, and then dried after air drying, thereby obtaining a composite desulfurizer suitable for desulfurization under oxygen-containing conditions.

[0016] According to the above scheme, in steps 1) and 2), sieving is performed through a 600-mesh sieve.

[0017] According to the above scheme, in step 1), the mass ratio of the hydroxyl iron oxide fine powder and the first binder is 5-9:1.

[0018] According to the above scheme, in step 1), the mass ratio of the hydroxyl iron oxide fine powder and water is 1:0.5-1.5.

[0019] According to the above scheme, in step 2), the mass ratio of the mixture and the second binder is 4-8:1.

[0020] According to the above scheme, in step 2), the mass ratio of the mixture and water is 1:0.5-1.0.

[0021] According to the above scheme, in the step 2), the mass ratio of copper oxide, zinc oxide and aluminum oxide is 5-10:20-50:30-70.

[0022] According to the above scheme, in the step 3), the mass ratio of the hydroxyl ferric oxide in the hydroxyl ferric oxide wet strip to the total mass of copper oxide, zinc oxide and aluminum oxide in the copper-zinc-aluminum wet strip is 1:1-3.

[0023] The application of the above-mentioned composite desulfurizer suitable for desulfurization under oxygen-containing conditions in desulfurization of sulfur-containing gas is provided, wherein the sulfur-containing gas comprises organic sulfur, inorganic sulfur and oxygen.

[0024] According to the above scheme, the content of organic sulfur is 1-100 ppm; the content of inorganic sulfur is 100-2000 ppm; and the content of oxygen is 0.05-1.2%.

[0025] According to the above scheme, the sulfur capacity of the composite desulfurizer is 10-20%.

[0026] According to the above scheme, the desulfurization rate of the composite desulfurizer is greater than 99%, and the total sulfur in the outlet is less than 0.1 ppm.

[0027] According to the above scheme, the process conditions when the composite desulfurizer is used for desulfurization are as follows: the space velocity is 250-1500 h -1 , and the temperature is 60-200 DEG C.

[0028] The application provides a composite desulfurizer suitable for desulfurization under oxygen-containing conditions, which is a double-layer composite structure, the inner layer comprises copper oxide, zinc oxide and aluminum oxide, and the outer layer is a hydroxyl ferric oxide layer.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] 1.The present application provides a kind of composite desulfurizer suitable for desulfurization in oxygen-containing condition, which is a double-layer composite structure, the inner layer includes copper oxide, zinc oxide, aluminum oxide, and the outer layer is iron oxyhydroxide layer;The cheap iron oxyhydroxide of outer layer is preferentially reacted with hydrogen sulfide and regenerated by oxygen, which improves the catalytic efficiency of iron oxyhydroxide and sulfur capacity on the one hand;On the other hand, it avoids the reaction of expensive copper-zinc in the inner layer with hydrogen sulfide, and promotes the efficiency of copper-zinc component in removing organic sulfur;In addition, it can also reduce the oxygen concentration, avoid the catalyst poisoning and deactivation caused by the presence of oxygen, and protect the inner layer of copper-zinc-aluminum;The obtained composite desulfurizer significantly improves the service life of desulfurizer under oxygen-containing condition, and the sulfur capacity of desulfurizer can be as high as 10-20%, and the simultaneous removal of organic sulfur and inorganic sulfur can be realized in one step, which effectively reduces the desulfurization cost and has important application prospect.

[0031] 2.The present application realizes the preparation of double-layer composite desulfurizer by double-layer extruder for the first time, which is simple in process and beneficial to industrial mass production. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0033] Example 1

[0034] A preparation method of a composite desulfurizer suitable for desulfurization in oxygen-containing condition is provided, comprising the following steps:

[0035] 1) Take iron oxyhydroxide and grind it to obtain fine powder of 600 mesh, then add 56g of bentonite and 2g of CMC to 500g of iron oxyhydroxide fine powder, mix well, then add 400g of water, mix evenly, and knead into a strip for standby.

[0036] 2) Take 200g, 600g and 600g of sieved copper oxide, zinc oxide and aluminum oxide respectively, mix well, then add 180g of bentonite and 5g of CMC to the mixture, mix well, then add 1300g of water, mix evenly, and knead into a strip for standby.

[0037] 3) Put the kneaded iron oxyhydroxide wet strip of step 1) and the kneaded copper-zinc-aluminum wet strip of step 2) into a double-layer extruder to extrude, obtain a wet strip with a diameter of 5mm, with iron oxyhydroxide as the outer layer and copper-zinc-aluminum as the inner layer, dry the wet strip, then dry it at 120℃ for 5h, to obtain a composite desulfurizer suitable for desulfurization in oxygen-containing condition.

[0038] Example 2

[0039] A preparation method of a composite desulfurizer suitable for desulfurization in oxygen-containing condition is provided, comprising the following steps:

[0040] 1) Take the hydroxyl iron oxide grinding sieve to get 600 mesh fine powder, then add 128g of clay binder to 700g of hydroxyl iron oxide fine powder, 2g of CMC, mix well, then add 600g of water, mix well, then knead into a long strip for use.

[0041] 2) Take 600 mesh sieved copper oxide, zinc oxide, aluminum oxide 120g, 500g, 1200g respectively, mix well, then add 400g of bentonite, 4g of CMC to the mixture, mix well, then add 1600g of water, mix well, then knead into a long strip for use.

[0042] 3) Put the kneaded hydroxyl iron oxide wet strip of step 1) and the kneaded copper zinc aluminum wet strip of step 2) into a double-layer extruder to get a 4mm diameter wet strip with hydroxyl iron oxide as the outer layer and copper zinc aluminum as the inner layer. After drying the wet strip, dry it at 140℃ for 2h to get a composite desulfurizer suitable for desulfurization under oxygen-containing conditions.

[0043] Example 3

[0044] A method for preparing a composite desulfurizer suitable for desulfurization under oxygen-containing conditions is provided, comprising the following steps:

[0045] 1) Take the hydroxyl iron oxide grinding sieve to get 600 mesh fine powder, then add 30g of bentonite, 40g of clay, 1g of CMC to 550g of hydroxyl iron oxide fine powder, mix well, then add 400g of water, mix well, then knead into a long strip for use.

[0046] 2) Take 600 mesh sieved copper oxide, zinc oxide, aluminum oxide 90g, 300g, 900g respectively, mix well, then add 300g of bentonite, 3g of CMC to the mixture, mix well, then add 1100g of water, mix well, then knead into a long strip for use.

[0047] 3) Put the kneaded hydroxyl iron oxide wet strip of step 1) and the kneaded copper zinc aluminum wet strip of step 2) into a double-layer extruder to get a 4mm diameter wet strip with hydroxyl iron oxide as the outer layer and copper zinc aluminum as the inner layer. After drying the wet strip, dry it at 130℃ for 3h to get a composite desulfurizer suitable for desulfurization under oxygen-containing conditions.

[0048] The desulfurizers prepared in the above Examples 1-3 were cut into small pieces of 4-5 mm in length, and 30 ml of each was subjected to a desulfurization comparison test under aerobic conditions with a commercially available copper-nickel desulfurizer (5% nickel oxide-25% copper oxide-70% alumina, mass %). Two different gas sources (Gas source 1 and Gas source 2) were selected for the test, and the results are shown in Tables 1 and 2. When the total sulfur at the outlet was ≥0.1 ppm, it was determined that the catalyst bed had been penetrated, and the test was stopped and the sulfur capacity of the desulfurizer was calculated. The sulfur capacity of the desulfurizer indicates the mass of sulfides removed (absorbed) by the desulfurizer per unit mass, and is measured by converting the sulfides to elemental sulfur, i.e., g (sulfur) / g (desulfurizer), and can also be expressed as %.

[0049] Table 1. Performance comparison of the desulfurizers obtained in Examples 1-3 and a commercially available copper-nickel desulfurizer with respect to Gas source 1

[0050]

[0051] In Table 1, the gas source and process conditions were as follows:

[0052] Gas source 1: H2S 0.1% + COS 0.01% + CH3SH 0.001% + O21%, with the balance being nitrogen.

[0053] Process conditions: space velocity 500 h-1, reaction temperature 150°C, and atmospheric pressure. -1

[0054] Table 2. Performance comparison of the desulfurizers obtained in Examples 1-3 and a commercially available copper-nickel desulfurizer with respect to Gas source 2

[0055]

[0056] In Table 2, the gas source and process conditions were as follows:

[0057] Gas source 2: H2S 0.12% + COS 0.005% + CS2 0.005% + O2 0.15%, with the balance being nitrogen.

[0058] Process conditions: space velocity 1000 h-1, reaction temperature 120°C, and atmospheric pressure. -1

[0059] ​​As can be seen from the data in Table 1-2, the desulfurizer obtained in the embodiment of the present application can realize high sulfur capacity under the oxygen-containing condition, and the sulfur capacity is as high as 13.4-20.2% (i.e. 100 g of the desulfurizer can remove 13.4-20.2 g of sulfur), which is much higher than that of the commercially available copper-nickel desulfurizer. When the oxygen content is low, i.e. 0.15%, the sulfur capacity of the commercially available copper-nickel desulfurizer is 8.7%, which is about 44% of the sulfur capacity of the desulfurizer obtained in Example 1; when the oxygen content is high, i.e. 1%, the sulfur capacity of the commercially available copper-nickel desulfurizer is only 4.6%, and the sulfur capacity of the embodiment of the present application can be as high as 20.2%, which is about 4.5 times of the sulfur capacity of the commercially available copper-nickel desulfurizer. It is illustrated that under the oxygen-containing condition, the oxygen content has a great influence on the desulfurization effect of the desulfurizer, and the composite desulfurizer of the present application can realize the simultaneous removal of organic sulfur and inorganic sulfur under the oxygen-containing condition, and has excellent desulfurization effect.

[0060] It should be understood that, for those skilled in the art, modifications or changes can be made according to the above description, and all these modifications and changes shall belong to the protection scope of the appended claims of the present application.

Claims

1. A composite desulfurizer suitable for desulfurization under an oxygen-containing condition, characterized by comprising: The composite desulfurizer is a double-layer composite structure; wherein: the outer layer is an iron oxide layer, including hydroxyl iron oxide and a first binder; the inner layer is a copper-zinc-aluminum layer, including copper oxide, zinc oxide, aluminum oxide and a second binder.

2. The composite desulfurizer according to claim 1, characterized by In the inner layer, the mass ratio of copper oxide, zinc oxide and aluminum oxide is 5-10:20-50:30-70.

3. The composite desulfurizer according to claim 1, characterized by In the outer layer, the mass ratio of hydroxyl iron oxide and the first binder is 5-9:1; in the inner layer, the mass ratio of the total mass of copper oxide, zinc oxide and aluminum oxide to the second binder is 4-8:

1.

4. The composite desulfurizer according to claim 1, characterized by The first binder and the second binder are independently selected from at least one of bentonite, clay and CMC.

5. The composite desulfurizer according to claim 1, characterized by The mass ratio of hydroxyl iron oxide in the outer layer to the total mass of copper oxide, zinc oxide and aluminum oxide in the inner layer is 1:1-3.

6. A method for preparing a composite desulfurizer according to any one of claims 1 to 5, which is suitable for desulfurization under an oxygen-containing condition, characterized by, The method comprises the following steps: 1) crushing and sieving hydroxyl iron oxide raw materials to obtain hydroxyl iron oxide fine powder, then mixing with the first binder, adding water, kneading to obtain a hydroxyl iron oxide wet strip; 2) sieving copper oxide, zinc oxide and aluminum oxide powders respectively, mixing to obtain a mixture, then mixing with the second binder, adding water, kneading to obtain a copper-zinc-aluminum wet strip; 3) placing the kneaded hydroxyl iron oxide wet strip obtained in step 1) and the copper-zinc-aluminum wet strip obtained in step 2) into a double-layer extruding machine to obtain a wet strip with the hydroxyl iron oxide layer as the outer layer and the copper-zinc-aluminum layer as the inner layer, and finally drying after air drying, thereby obtaining a composite desulfurizer suitable for desulfurization under oxygen-containing conditions.

7. The production method according to claim 6, characterized by, In step 1), the mass ratio of hydroxyl iron oxide fine powder to the first binder is 5-9:1; in step 2), the mass ratio of the mixture to the second binder is 4-8:

1.

8. The preparation method according to claim 6, characterized in that In step 1), the mass ratio of hydroxyl iron oxide fine powder to water is 1:0.5-1.5; in step 2), the mass ratio of the mixture to water is 1:0.5-1.

0.

9. The preparation method according to claim 6, characterized in that In step 3), the mass ratio of hydroxyl iron oxide in the hydroxyl iron oxide wet strip to the total mass of copper oxide, zinc oxide and aluminum oxide in the copper-zinc-aluminum wet strip is 1:1-3.

10. Use of a composite desulfurizer according to any one of claims 1 to 5 for the desulfurization of a sulfur-containing gas under oxidizing conditions, characterized in that, The sulfur-containing gas comprises organic sulfur, inorganic sulfur and oxygen.

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