A desulfurization synergist and its preparation method and application

Abstract

The present invention relates to the field of catalyst technology, and proposes a desulfurization synergist and its preparation method and application. The desulfurization synergist includes a carrier and an active component; the carrier is hydrated aluminum silicate nanofiber; the active component includes cobalt titanate; the preparation method of the desulfurization synergist comprises the following steps: S1, mixing a precursor of cobalt titanate and hydrated aluminum silicate nanofiber, filtering, taking a precipitate, and obtaining a mixture; calcining the mixture to obtain cobalt titanate / hydrated aluminum silicate nanofiber; S2, mixing the cobalt titanate / hydrated aluminum silicate nanofiber with a precursor of cobalt trioxide, and calcining under a hydrogen atmosphere to obtain a desulfurization synergist. Through the above technical solution, the problem of low desulfurization efficiency during limestone-gypsum wet desulfurization in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a desulfurization synergist, a preparation method thereof, and an application thereof. Background Art

[0002] Flue gas desulfurization (FGD) refers to the process of using absorbents or adsorbents to remove sulfur dioxide from flue gas and convert it into more stable sulfur-containing compounds or elemental sulfur. Current FGD processes can be divided into two main categories: wet FGD and dry / semi-dry FGD. The wet FGD process primarily utilizes a solution or slurry containing an absorbent to desulfurize and treat the desulfurized product in a wet state. Common wet FGD processes include: limestone-gypsum wet FGD, wet lime / magnesium oxide-lime FGD, ammonia-based FGD, dual-alkali FGD, and seawater FGD.

[0003] Limestone-gypsum wet flue gas desulfurization is a type of wet flue gas desulfurization process. The process reaction is carried out in the absorption tower. The flue gas entering the absorption tower contacts and mixes with the limestone slurry. The sulfur dioxide in the flue gas reacts chemically with the CaCO3 in the absorbent slurry and the O2 blown in. The desulfurized flue gas passes through a demister to remove droplets and is heated in a flue gas reheater before being discharged into the atmosphere. By using appropriate additives in the limestone-gypsum wet flue gas desulfurization process, the SO2 removal efficiency can be improved, which is an important measure to optimize wet flue gas desulfurization.

[0004] The current flue gas desulfurization still has low flue gas desulfurization efficiency, which causes power plants to invest heavily in the transformation of equipment and increase costs. Therefore, it is necessary to improve the desulfurization efficiency of flue gas desulfurization, reduce costs, and meet national emission standards. Summary of the Invention

[0005] The present invention provides a desulfurization synergist, a preparation method and application thereof, which solves the problem of low desulfurization efficiency in limestone-gypsum wet desulfurization in the related art.

[0006] The technical solutions of the present invention are as follows:

[0007] The present invention provides a desulfurization synergist, which comprises a carrier and an active component; the carrier is hydrated aluminum silicate nanofiber; and the active component comprises cobalt titanate.

[0008] As a further technical solution, the precursors of the cobalt titanate are tetraisopropyl titanate and cobalt oxalate.

[0009] As a further technical solution, the mass ratio of the carrier, tetraisopropyl titanate and cobalt oxalate is 4:1:1~3.

[0010] As a further technical solution, the active ingredient also includes cobalt tetroxide.

[0011] As a further technical solution, the precursor of the cobalt trioxide is one or more of cobalt oxalate, cobalt acetate and cobalt nitrate.

[0012] As a further technical solution, the mass ratio of the carrier to the cobaltous oxide precursor is 5:1~2.

[0013] The present invention also provides a method for preparing a desulfurization synergist, comprising the following steps:

[0014] Tetraisopropyl titanate, cobalt oxalate and hydrated aluminum silicate nanofibers are mixed, filtered, and precipitated to obtain a mixture; the mixture is calcined to obtain a desulfurization synergist.

[0015] As a further technical solution, the mixing time is 3 to 5 hours; the calcination temperature is 700 to 800° C. and the calcination time is 2 to 3 hours.

[0016] The present invention also provides a method for preparing a desulfurization synergist, comprising the following steps:

[0017] S1. Mixing tetraisopropyl titanate, cobalt oxalate, and hydrated aluminum silicate nanofibers for 3-5 hours, filtering, and collecting a precipitate to obtain a mixture; and calcining the mixture at 700-800° C. for 2-3 hours to obtain cobalt titanate / hydrated aluminum silicate nanofibers;

[0018] S2. After mixing the cobalt titanate / hydrated aluminum silicate nanofibers with a cobalt trioxide precursor, calcining the mixture at 800-900° C. for 1-2 hours in a hydrogen atmosphere to obtain a desulfurization synergist.

[0019] The present invention also proposes the use of the desulfurization synergist and the desulfurization synergist prepared by the preparation method in wet flue gas desulfurization.

[0020] The working principle and beneficial effects of the present invention are:

[0021] 1. In the present invention, the desulfurization synergist uses hydrated aluminum silicate nanofibers as a carrier and loads the active ingredient cobalt titanate. The excellent aspect ratio and hollow structure of the hydrated aluminum silicate nanofibers are utilized to provide multiple active sites for desulfurization, and at the same time, synergistically enhance the effect with cobalt titanate. The prepared desulfurization synergist is applied to limestone-gypsum wet desulfurization, which significantly improves the desulfurization efficiency.

[0022] 2. In the present invention, by adjusting the mass ratio of the carrier, tetraisopropyl titanate and cobalt oxalate, the carrier and the active component are fully synergistically enhanced, and the desulfurization synergist prepared further improves the desulfurization efficiency during limestone-gypsum wet desulfurization.

[0023] 3. In the present invention, in addition to cobalt titanate, the active component of the desulfurization synergist also introduces cobalt tetroxide. Cobalt tetroxide, cobalt titanate and the carrier hydrated aluminum silicate nanofiber cooperate with each other to further improve the desulfurization efficiency of limestone-gypsum wet desulfurization. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0025] In the following examples and comparative examples, hydrated aluminum silicate nanofibers with an inner diameter of 10-20 nm, an outer diameter of 40-70 nm, and a fiber length of 200-1000 nm were purchased from Jiangxi Dishi Mineral Fiber Technology Co., Ltd.; tetraisopropyl titanate with a titanium content of 16.68%; cobalt oxalate with a purity of 99%; and cobalt acetate with a purity of 99%.

[0026] Example 1

[0027] The preparation method of the desulfurization synergist comprises the following steps:

[0028] Tetraisopropyl titanate, cobalt oxalate and hydrated aluminum silicate nanofibers are mixed for 3 hours, filtered, and the precipitate is collected to obtain a mixture; the mixture is calcined at 700°C for 3 hours to obtain a desulfurization enhancer; wherein the mass ratio of hydrated aluminum silicate nanofibers, tetraisopropyl titanate and cobalt oxalate is 4:1:0.5.

[0029] Example 2

[0030] The preparation method of the desulfurization synergist comprises the following steps:

[0031] Tetraisopropyl titanate, cobalt oxalate and hydrated aluminum silicate nanofibers are mixed for 4 hours, filtered, and the precipitate is collected to obtain a mixture; the mixture is calcined at 800°C for 2 hours to obtain a desulfurization enhancer; wherein the mass ratio of hydrated aluminum silicate nanofibers, tetraisopropyl titanate and cobalt oxalate is 4:1:0.5.

[0032] Example 3

[0033] The preparation method of the desulfurization synergist comprises the following steps:

[0034] Tetraisopropyl titanate, cobalt oxalate and hydrated aluminum silicate nanofibers are mixed for 5 hours, filtered, and a precipitate is collected to obtain a mixture; the mixture is calcined at 800°C for 2 hours to obtain a desulfurization synergist; wherein the mass ratio of hydrated aluminum silicate nanofibers, tetraisopropyl titanate and cobalt oxalate is 4:1:0.5.

[0035] Example 4

[0036] The only difference between this embodiment and embodiment 3 is that the mass ratio of hydrated aluminum silicate nanofibers, tetraisopropyl titanate and cobalt oxalate is 4:1:4.

[0037] Example 5

[0038] The only difference between this embodiment and embodiment 3 is that the mass ratio of hydrated aluminum silicate nanofibers, tetraisopropyl titanate and cobalt oxalate is 4:1:1.

[0039] Example 6

[0040] The only difference between this embodiment and embodiment 3 is that the mass ratio of hydrated aluminum silicate nanofibers, tetraisopropyl titanate and cobalt oxalate is 4:1:3.

[0041] Example 7

[0042] The only difference between this embodiment and embodiment 6 is the preparation method of the desulfurization synergist, which includes the following steps:

[0043] S1. Tetraisopropyl titanate, cobalt oxalate, and hydrated aluminum silicate nanofibers were mixed for 5 hours, filtered, and a precipitate was collected to obtain a mixture; and the mixture was calcined at 800° C. for 2 hours to obtain cobalt titanate / hydrated aluminum silicate nanofibers;

[0044] S2. After mixing cobalt titanate / hydrated aluminum silicate nanofibers and cobalt acetate, calcining them at 800° C. for 2 hours in a hydrogen atmosphere to obtain a desulfurization synergist; wherein the mass ratio of hydrated aluminum silicate nanofibers to cobalt acetate is 5:1.

[0045] Example 8

[0046] The only difference between this embodiment and embodiment 7 is that in S2 of the preparation method of the desulfurization synergist, cobalt titanate / hydrated aluminum silicate nanofibers and cobalt nitrate are mixed and then calcined at 900°C for 1 hour in a hydrogen atmosphere to obtain a desulfurization synergist, wherein the mass ratio of hydrated aluminum silicate nanofibers to cobalt nitrate is 5:1.

[0047] Example 9

[0048] The only difference between this embodiment and embodiment 8 is that the mass ratio of the precursor of hydrated aluminum silicate nanofibers and cobalt trioxide is 5:2.

[0049] Comparative Example 1

[0050] The only difference between this comparative example and Example 3 is that hydrated aluminum silicate nanofibers are used as the desulfurization synergist.

[0051] Comparative Example 2

[0052] The only difference between this comparative example and Example 8 is that the active ingredient of the desulfurization synergist is cobalt tetroxide, and the active ingredient cobalt titanate is not contained;

[0053] The preparation method of the desulfurization synergist comprises the following steps:

[0054] After mixing hydrated aluminum silicate nanofibers with cobalt nitrate, the mixture was calcined at 900° C. for 1 hour in a hydrogen atmosphere to obtain a desulfurization synergist, wherein the mass ratio of hydrated aluminum silicate nanofibers to cobalt nitrate was 5:1.

[0055] The desulfurization synergists in Examples 1 to 9 and Comparative Examples 1 to 2 were respectively applied to limestone-gypsum wet desulfurization. The desulfurization synergist and limestone slurry were mixed in a mass ratio of 3:100 and added to the absorption tower. After the desulfurization system was operated for 60 minutes, the concentration of sulfur dioxide at the flue gas outlet was counted. According to desulfurization rate = [(SO2 concentration in flue gas before desulfurization - SO2 concentration in flue gas after desulfurization) / SO2 concentration in flue gas before desulfurization] × 100%, the desulfurization rates of Examples 1 to 9 and Comparative Examples 1 to 2 were respectively calculated.

[0056] The desulfurization rate of the limestone slurry without desulfurization synergist was calculated to be 82.0%. The desulfurization test results of Examples 1 to 9 and Comparative Examples 1 to 2 are shown in the following table:

[0057]

[0058] By comparing the data of Examples 1 to 9 and Comparative Example 1, it is found that compared with Comparative Example 1, the desulfurization synergists of Examples 1 to 9 have higher desulfurization rates after being applied to limestone-gypsum wet desulfurization, indicating that the desulfurization synergist prepared by using hydrated aluminum silicate nanofibers as a carrier and loading the active ingredient cobalt titanate can significantly improve the desulfurization efficiency.

[0059] By comparing the data of Examples 3-4 and 5-6, it is found that the desulfurization rate of the desulfurization synergist of Examples 5-6 is higher than that of Examples 3-4, indicating that the desulfurization efficiency of the desulfurization synergist can be further improved by adjusting the mass ratio of the carrier, tetraisopropyl titanate and cobalt oxalate.

[0060] By comparing the data of Examples 6 to 9 and Comparative Example 2, it is found that the desulfurization synergists of Examples 7 to 9 have higher desulfurization efficiency than the desulfurization synergists of Example 6 and Comparative Example 2, indicating that the introduction of cobalt tetroxide into the active component allows cobalt tetroxide, cobalt titanate and the carrier hydrated aluminum silicate nanofibers to cooperate with each other, which can further improve the desulfurization efficiency of limestone-gypsum wet desulfurization.

[0061] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A desulfurization synergist, characterized in that: The desulfurization synergist comprises a carrier and an active component; the carrier is hydrated aluminum silicate nanofiber; and the active component comprises cobalt titanate.

2. A desulfurization synergist according to claim 1, characterized in that, The precursors of the cobalt titanate are tetraisopropyl titanate and cobalt oxalate.

3. A desulfurization synergist according to claim 2, characterized in that, The mass ratio of the carrier, tetraisopropyl titanate and cobalt oxalate is 4:1:1-3.

4. A desulfurization synergist according to claim 2, characterized in that, The active component also includes cobalt tetroxide.

5. A desulfurization synergist according to claim 4, characterized in that: The precursor of the cobalt trioxide is one or more of cobalt oxalate, cobalt acetate and cobalt nitrate.

6. A desulfurization synergist according to claim 5, characterized in that: The mass ratio of the carrier to the cobaltous oxide precursor is 5:1-2.

7. The method for preparing a desulfurization synergist according to any one of claims 2 to 3, characterized in that: The following steps are involved: Tetraisopropyl titanate, cobalt oxalate and hydrated aluminum silicate nanofibers are mixed, filtered, and precipitated to obtain a mixture; the mixture is calcined to obtain a desulfurization synergist.

8. The method for preparing a desulfurization synergist according to claim 7, characterized in that: The mixing time is 3-5 hours; the calcination temperature is 700-800° C. and the calcination time is 2-3 hours.

9. The method for preparing a desulfurization synergist according to any one of claims 5 to 6, characterized in that: The following steps are involved: S1. Mixing tetraisopropyl titanate, cobalt oxalate, and hydrated aluminum silicate nanofibers for 3-5 hours, filtering, and collecting a precipitate to obtain a mixture; and calcining the mixture at 700-800° C. for 2-3 hours to obtain cobalt titanate / hydrated aluminum silicate nanofibers; S2. After mixing the cobalt titanate / hydrated aluminum silicate nanofibers with a cobalt trioxide precursor, calcining the mixture at 800-900° C. for 1-2 hours in a hydrogen atmosphere to obtain a desulfurization synergist.

10. Use of the desulfurization synergist according to any one of claims 1 to 6 or the desulfurization synergist prepared by the preparation method according to any one of claims 7 to 9 in wet flue gas desulfurization.

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