Calcium-based dry desulfurization agent as well as preparation method and application thereof

Abstract

The invention relates to a calcium-based dry desulfurizer as well as a preparation method and application thereof, and belongs to the technical field of desulfurizers. The calcium-based dry desulfurization agent is prepared from the following components in parts by mass: 50 to 70 parts of active calcium oxide, 5 to 15 parts of calcined calcium silicate, 5 to 15 parts of nano titanium dioxide, 10 to 20 parts of attapulgite, 3 to 8 parts of sodium lignin sulfonate and 2 to 5 parts of an additive. The calcium silicate is calcined to form a stable crystal and a gap structure, the attapulgite and other components form a stable composite structure, the sodium lignin sulfonate forms a protective film, and the potassium sulfate improves the sintering performance, so that the phenomena of caking, pulverization and the like of the desulfurizer in the use process are effectively prevented, and the stability and the mechanical strength of the desulfurizer are improved; the service life of the desulfurizing agent is prolonged, and the long-term stable operation of a desulfurization system is ensured; all the components cooperate with one another, so that the activity of the desulfurizer is remarkably improved, the desulfurization efficiency of 96% or above is achieved, and the environment-friendly requirement is met.

Description

Technical Field

[0001] The present invention relates to a calcium-based dry desulfurizer, a preparation method thereof and an application thereof, and belongs to the technical field of desulfurizers. Background Art

[0002] With the increasingly strict environmental protection requirements, flue gas desulfurization has become a key link in industrial waste gas treatment. The dry desulfurization technology has been widely used in the field of flue gas desulfurization due to its advantages such as simple process flow and no wastewater discharge. Among them, the calcium-based dry desulfurizer is a commonly used desulfurizer in the dry desulfurization technology because of its wide raw material sources and low price.

[0003] However, there are many problems with traditional calcium-based dry desulfurizers. On the one hand, its desulfurization activity is low, resulting in the desulfurization efficiency being difficult to reach a high level and unable to meet the increasingly stringent environmental protection standards; on the other hand, during the desulfurization process, the stability of the desulfurizer is poor, and phenomena such as caking and pulverization are likely to occur, affecting the service life of the desulfurizer and the normal operation of the desulfurization system. In addition, the desulfurization performance of traditional calcium-based dry desulfurizers will decrease significantly in high-temperature environments, limiting their application in some high-temperature flue gas desulfurization scenarios. Therefore, it is of great practical significance to develop a new type of calcium-based dry desulfurizer with high desulfurization efficiency and high stability. Summary of the Invention

[0004] The purpose of the present invention is to provide a calcium-based dry desulfurizer, a preparation method thereof and an application thereof, to solve the problems of low desulfurization efficiency and poor stability of traditional calcium-based dry desulfurizers, and achieve a desulfurization efficiency of more than 95%; at the same time, provide a preparation method and an application of the desulfurizer, and provide an efficient and stable technical solution for industrial flue gas desulfurization.

[0005] One of the purposes of the present invention is to provide a calcium-based dry desulfurizer, which comprises the following components by mass parts: 50-70 parts of active calcium oxide, 5-15 parts of calcined calcium silicate, 5-15 parts of nano-titanium dioxide, 10-20 parts of attapulgite, 3-8 parts of sodium lignosulfonate, and 2-5 parts of an additive.

[0006] The technical effects of adopting the above solution are as follows: As the main active component for desulfurization, the reactive calcium oxide has increased specific surface area and porosity through grinding treatment and preparation process under low-temperature inert gas conditions, thereby enhancing its reactivity with sulfur dioxide in flue gas; the calcined calcium silicate forms a stable crystal structure at high temperature, can maintain the pore structure at the desulfurization reaction temperature, prevent the sintering and agglomeration of reactive calcium oxide particles, and extend the service life of the desulfurizer. Its high-hardness particles provide a skeleton support for the desulfurizer, reducing the pulverization rate; nano-titanium dioxide can promote the oxidation reaction of sulfur dioxide to a certain extent, improve the desulfurization reaction rate. At the same time, its nano-scale particle size can fill the pores of reactive calcium oxide, improve the pore structure of the desulfurizer, and enhance the stability of the desulfurizer; attapulgite can adsorb some impurities in the flue gas, reduce the interference of impurities on the desulfurization reaction. At the same time, it interacts with reactive calcium oxide and nano-titanium dioxide to form a stable composite structure, further improving the stability and mechanical strength of the desulfurizer; sodium lignosulfonate as a dispersant can effectively prevent the agglomeration of each component during the preparation process, make each component evenly dispersed, and ensure the uniformity of the desulfurizer performance. In addition, sodium lignosulfonate can also form a protective film on the surface of the desulfurizer, slow down the reaction of the desulfurizer with moisture and carbon dioxide in the air, and extend the storage time of the desulfurizer.

[0007] Based on the above technical solution, the present invention can be further improved as follows:

[0008] Further, the calcined calcium silicate is β-Ca2SiO4, the calcination temperature is 1200 - 1400 °C, and the average particle size is 1 - 10 μm.

[0009] Further, the additive is a mixture of lanthanum nitrate and potassium sulfate.

[0010] The effects of adopting the above solution are as follows: Lanthanum nitrate can increase the lattice defects of reactive calcium oxide and the number of active sites, thereby improving the desulfurization activity of the desulfurizer; potassium sulfate can improve the sintering performance of the desulfurizer, prevent the caking phenomenon of the desulfurizer at high temperature, and enhance the stability of the desulfurizer in a high-temperature environment.

[0011] Further, the mass ratio of lanthanum nitrate to potassium sulfate is 1:1 - 2, the purity of lanthanum nitrate ≥ 99%, and the purity of potassium sulfate ≥ 98%.

[0012] Further, the purity of the reactive calcium oxide ≥ 92%, the specific surface area ≥ 50m 2 / g, and the average particle size is 5 - 10 μm.

[0013] Further, the purity of the nano-titanium dioxide ≥ 98%, the particle size range is 20 - 50 nm, and the anatase content ≥ 85%.

[0014] Further, the specific surface area of the attapulgite clay is ≥ 150 m 2 / g, the cation exchange capacity is ≥ 100 mmol / 100 g, and the silicon-aluminum ratio is 2.5 - 3.5.

[0015] Further, the sulfonation degree of the sodium lignosulfonate is 1.2 - 1.8 mmol / g, and the molecular weight is 3000 - 8000.

[0016] The second object of the present invention is to provide a preparation method of the above calcium-based dry desulfurizer, comprising the following steps:

[0017] (1) Raw material pretreatment: Grind the activated calcium oxide to make its particle size reach 5 - 10 μm; Purify and dry the attapulgite clay to remove impurities and moisture therein;

[0018] (2) Mixing: Weigh activated calcium oxide, calcined calcium silicate, nano-titanium dioxide, attapulgite clay, sodium lignosulfonate and additives by mass parts, add them to a high-speed mixer, and stir at a speed of 800 - 1200 r / min for 20 - 30 min to make each component fully mixed evenly to obtain a mixed material;

[0019] (3) Granulation: Add water to the mixed material to make a wet material with a water content of 15 - 20%, and then make the wet material into particles with a particle size of 3 - 5 mm through an extrusion granulator;

[0020] (4) Drying: Dry the granulated particles at 100 - 120 °C for 2 - 4 h to remove the moisture in the particles;

[0021] (5) Calcination: Calcinate the dried particles at 600 - 800 °C for 1 - 2 h to make chemical reactions occur between each component to form a stable composite structure, thus obtaining the calcium-based dry desulfurizer.

[0022] Further, in step (1), the grinding treatment is carried out under an inert gas condition.

[0023] The third object of the present invention is to provide an application of the above calcium-based dry desulfurizer in flue gas desulfurization.

[0024] The technical solution provided by the present invention has the following beneficial effects compared with the prior art:

[0025] 1. By compounding activated calcium oxide, calcined calcium carbonate, nano-titanium dioxide, attapulgite clay and sodium lignosulfonate and adding a compound additive in the present invention, each component synergizes with each other, significantly improving the desulfurization activity of the desulfurizer, achieving a desulfurization efficiency of more than 96%, and meeting the environmental protection requirements.

[0026] 2. The present invention forms stable crystal and void structures by calcining calcium silicate, attapulgite forms a stable composite structure with other components, sodium lignosulfonate forms a protective film, and potassium sulfate improves the sintering performance, effectively preventing phenomena such as caking and pulverization of the desulfurizer during use, improving the stability and mechanical strength of the desulfurizer, extending the service life of the desulfurizer, and ensuring the long-term stable operation of the desulfurization system.

[0027] 3. Due to the improvement of the sintering performance by potassium sulfate in the additive and the synergistic effect among components, the prepared desulfurizer can still maintain good desulfurization performance under high-temperature environments (120 - 180 °C), broadening its application range and being applicable to more high-temperature flue gas desulfurization scenarios.

[0028] 4. The preparation method of the present invention adopts conventional processes such as grinding, mixing, granulating, drying, and calcining, which is simple in operation, easy to realize industrial production, has low production costs, and has good economic benefits and application prospects. Specific Embodiments

[0029] The principles and features of the present invention will be described below in conjunction with examples. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0030] Example 1

[0031] A calcium-based dry desulfurizer, by mass, includes the following components: 50 parts of active calcium oxide (purity 92%, specific surface area 55 m 2 / g, average particle size 8 μm), 15 parts of calcined calcium silicate (β-Ca2SiO4, calcined at 1250 °C for 2 h, average particle size 5 μm), 5 parts of nano-titanium dioxide (purity 98%, average particle size 35 μm, anatase content 85%), 10 parts of attapulgite (specific surface area 160 m 2 / g, cation exchange capacity 120 mmol / 100 g, silicon-aluminum ratio 3), 3 parts of sodium lignosulfonate (sulfonation degree 1.5 mmol / g, molecular weight 6000), and 2 parts of additive (lanthanum nitrate: potassium sulfate = 1:1, purity of lanthanum nitrate 99%, purity of potassium sulfate 98%).

[0032] A preparation method of a calcium-based dry desulfurizer includes the following steps:

[0033] (1) Raw material pretreatment: Grind the active calcium oxide under nitrogen conditions to make its particle size reach 5 - 10 μm; purify and dry the attapulgite to remove impurities and moisture therein;

[0034] (2) Mixing: Weigh calcium oxide, calcined calcium silicate, nano-titanium dioxide, attapulgite, sodium lignosulfonate and additives by mass parts, add them to a high-speed mixer, and stir at a speed of 1000 r / min for 20 min to fully mix and homogenize each component, obtaining a mixed material;

[0035] (3) Granulation: Add water to the mixed material to make a wet material with a water content of 15%, and then use an extrusion granulator to make the wet material into particles with a particle size of 3 - 5 mm;

[0036] (4) Drying: Dry the granulated particles at 100 °C for 2 h to remove the moisture in the particles;

[0037] (5) Calcination: Calcinate the dried particles at 600 °C for 1 h to cause a chemical reaction between each component to form a stable composite structure, obtaining the calcium-based dry desulfurizer.

[0038] Example 2

[0039] A calcium-based dry desulfurizer, by mass parts, includes the following components: calcium oxide (purity 92%, specific surface area 55 m 2 / g, average particle size 8 μm) 60 parts, calcined calcium silicate (β-Ca2SiO4, calcined at 1250 °C for 2 h, average particle size 5 μm) 10 parts, nano-titanium dioxide (purity 98%, average particle size 35 μm, anatase content 85%) 10 parts, attapulgite (specific surface area 160 m 2 / g, cation exchange capacity 120 mmol / 100 g, silicon-aluminum ratio 3) 15 parts, sodium lignosulfonate (sulfonation degree 1.5 mmol / g, molecular weight 6000) 5 parts, additive 3 parts (lanthanum nitrate: potassium sulfate = 1:1.5, purity of lanthanum nitrate 99%, purity of potassium sulfate 98%).

[0040] A preparation method of a calcium-based dry desulfurizer includes the following steps:

[0041] (1) Raw material pretreatment: Grind calcium oxide under nitrogen conditions to make its particle size reach 5 - 10 μm; purify and dry attapulgite to remove impurities and moisture in it;

[0042] (2) Mixing: Weigh calcium oxide, calcined calcium silicate, nano-titanium dioxide, attapulgite, sodium lignosulfonate and additives by mass parts, add them to a high-speed mixer, and stir at a speed of 1000 r / min for 25 min to fully mix and homogenize each component, obtaining a mixed material;

[0043] (3) Granulation: Water is added to the mixed materials to make wet materials with a water content of 18%, and then the wet materials are made into particles with a particle size of 3 - 5 mm through an extrusion granulator;

[0044] (4) Drying: The granulated particles are dried at 110 °C for 3 h to remove the moisture in the particles;

[0045] (5) Calcination: The dried particles are calcined at 700 °C for 1.5 h to cause chemical reactions between the components to form a stable composite structure, obtaining the calcium-based dry desulfurizer.

[0046] Example 3

[0047] A calcium-based dry desulfurizer, by mass fraction, includes the following components: 70 parts of active calcium oxide (purity 92%, specific surface area 55 m 2 / g, average particle size 8 μm), 5 parts of calcined calcium silicate β-Ca2SiO4, calcined at 1250 °C for 2 h, average particle size 5 μm), 15 parts of nano-titanium dioxide (purity 98%, average particle size 35 μm, anatase content 85%), 20 parts of attapulgite (specific surface area 160 m 2 / g, cation exchange capacity 120 mmol / 100 g, silicon-aluminum ratio 3), 8 parts of sodium lignosulfonate (sulfonation degree 1.5 mmol / g, molecular weight 6000), and 5 parts of additive (lanthanum nitrate: potassium sulfate = 1:2, purity of lanthanum nitrate 99%, purity of potassium sulfate 98%).

[0048] A preparation method of a calcium-based dry desulfurizer includes the following steps:

[0049] (1) Raw material pretreatment: The active calcium oxide is ground under nitrogen conditions to make its particle size reach 5 - 10 μm; the attapulgite is purified and dried to remove the impurities and moisture in it;

[0050] (2) Mixing: Weigh active calcium oxide, calcined calcium silicate, nano-titanium dioxide, attapulgite, sodium lignosulfonate and additive by mass fraction, add them to a high-speed mixer, and stir at a speed of 1000 r / min for 30 min to make the components fully mixed evenly, obtaining mixed materials;

[0051] (3) Granulation: Water is added to the mixed materials to make wet materials with a water content of 20%, and then the wet materials are made into particles with a particle size of 3 - 5 mm through an extrusion granulator;

[0052] (4) Drying: The granulated particles are dried at 120 °C for 4 h to remove the moisture in the particles;

[0053] (5) Calcination: The dried particles are calcined at 800 °C for 2 h to cause chemical reactions between the components to form a stable composite structure, thereby obtaining the calcium-based dry desulfurizer.

[0054] Comparative Example 1

[0055] The components of the desulfurizer only include active calcium oxide, and the preparation method is the same as that of Example 2.

[0056] Comparative Example 2

[0057] A calcium-based dry desulfurizer, by mass, includes the following components: active calcium oxide (purity 92%, specific surface area 55 m 2 / g, average particle size 8 μm) 60 parts, nano-titanium dioxide (purity 98%, average particle size 35 μm, anatase content 85%) 10 parts, attapulgite (specific surface area 160 m 2 / g, cation exchange capacity 120 mmol / 100 g, silicon-aluminum ratio 3) 15 parts, sodium lignosulfonate (sulfonation degree 1.5 mmol / g, molecular weight 6000) 5 parts, additive 3 parts (lanthanum nitrate: potassium sulfate = 1:1.5, purity of lanthanum nitrate 99%, purity of potassium sulfate 98%).

[0058] A preparation method of a calcium-based dry desulfurizer includes the following steps:

[0059] (1) Raw material pretreatment: Grind the active calcium oxide under nitrogen conditions to make its particle size reach 5 - 10 μm; purify and dry the attapulgite to remove impurities and moisture therein;

[0060] (2) Mixing: Weigh the active calcium oxide, nano-titanium dioxide, attapulgite, sodium lignosulfonate and additive by mass, add them to a high-speed mixer, and stir at a speed of 1000 r / min for 25 min to make the components fully mixed uniformly, obtaining a mixed material;

[0061] (3) Granulation: Add water to the mixed material to make a wet material with a water content of 18%, and then use an extrusion granulator to make the wet material into particles with a particle size of 3 - 5 mm;

[0062] (4) Drying: Dry the granulated particles at 110 °C for 3 h to remove the moisture in the particles;

[0063] (5) Calcination: Calcinate the dried particles at 700 °C for 1.5 h to cause chemical reactions between the components to form a stable composite structure, thereby obtaining the calcium-based dry desulfurizer.

[0064] Comparative Example 3

[0065] A calcium-based dry desulfurizer, by mass fraction, comprises the following components: active calcium oxide (purity 92%, specific surface area 55 m 2 / g, average particle size 8 μm) 60 parts, calcined calcium silicate (β-Ca2SiO4, calcined at 1250 °C for 2 h, average particle size 5 μm) 10 parts, attapulgite (specific surface area 160 m 2 / g, cation exchange capacity 120 mmol / 100 g, silicon-aluminum ratio 3) 15 parts, sodium lignosulfonate (sulfonation degree 1.5 mmol / g, molecular weight 6000) 5 parts, additive 3 parts (lanthanum nitrate: potassium sulfate = 1:1.5, purity of lanthanum nitrate 99%, purity of potassium sulfate 98%).

[0066] A preparation method of the calcium-based dry desulfurizer comprises the following steps:

[0067] (1) Raw material pretreatment: Grind the active calcium oxide under nitrogen conditions to make its particle size reach 5 - 10 μm; Purify and dry the attapulgite to remove impurities and moisture therein;

[0068] (2) Mixing: Weigh the active calcium oxide, calcined calcium silicate, attapulgite, sodium lignosulfonate and additive by mass fraction, add them to a high-speed mixer, and stir at a speed of 1000 r / min for 25 min to fully mix and homogenize each component to obtain a mixed material;

[0069] (3) Granulation: Add water to the mixed material to make a wet material with a water content of 18%, and then make the wet material into particles with a particle size of 3 - 5 mm through an extrusion granulator;

[0070] (4) Drying: Dry the granulated particles at 110 °C for 3 h to remove the moisture in the particles;

[0071] (5) Calcination: Calcinate the dried particles at 700 °C for 1.5 h to cause chemical reactions between each component to form a stable composite structure, thus obtaining the calcium-based dry desulfurizer.

[0072] Comparative Example 4

[0073] A calcium-based dry desulfurizer, by mass fraction, comprises the following components: active calcium oxide (purity 92%, specific surface area 55 m 260 parts of active calcium oxide (purity 92%, specific surface area 55 m² / g, average particle size 8 μm), 10 parts of calcined calcium silicate (β-Ca₂SiO₄, calcined at 1250 °C for 2 h, average particle size 5 μm), 10 parts of nano-titanium dioxide (purity 98%, average particle size 35 μm, anatase content 85%), 5 parts of sodium lignosulfonate (sulfonation degree 1.5 mmol / g, molecular weight 6000), and 3 parts of additive (lanthanum nitrate: potassium sulfate = 1:1.5, purity of lanthanum nitrate 99%, purity of potassium sulfate 98%).

[0074] A preparation method of a calcium-based dry desulfurizer, comprising the following steps:

[0075] (1) Raw material pretreatment: Grind active calcium oxide under nitrogen conditions to make its particle size reach 5 - 10 μm; Purify and dry attapulgite to remove impurities and moisture therein;

[0076] (2) Mixing: Weigh active calcium oxide, calcined calcium silicate, nano-titanium dioxide, sodium lignosulfonate and additive by mass parts, add them to a high-speed mixer, and stir at a speed of 1000 r / min for 25 min to make each component fully mixed evenly to obtain a mixed material;

[0077] (3) Granulation: Add water to the mixed material to make a wet material with a water content of 18%, and then use an extrusion granulator to make the wet material into particles with a particle size of 3 - 5 mm;

[0078] (4) Drying: Dry the granulated particles at 110 °C for 3 h to remove the moisture in the particles;

[0079] (5) Calcination: Calcinate the dried particles at 700 °C for 1.5 h to cause a chemical reaction between each component to form a stable composite structure, and obtain the calcium-based dry desulfurizer.

[0080] Control Example 5

[0081] A calcium-based dry desulfurizer, by mass parts, comprising the following components: active calcium oxide (purity 92%, specific surface area 55 m 2 / g, average particle size 8 μm) 60 parts, calcined calcium silicate (β-Ca₂SiO₄, calcined at 1250 °C for 2 h, average particle size 5 μm) 10 parts, nano-titanium dioxide (purity 98%, average particle size 35 μm, anatase content 85%) 10 parts, attapulgite (specific surface area 160 m 2 / g, cation exchange capacity 120 mmol / 100 g, silicon-aluminum ratio 3) 15 parts, and additive 3 parts (lanthanum nitrate: potassium sulfate = 1:1.5, purity of lanthanum nitrate 99%, purity of potassium sulfate 98%).

[0082] A preparation method of a calcium-based dry desulfurizer, comprising the following steps:

[0083] (1) Raw material pretreatment: Grind activated calcium oxide under nitrogen conditions to make its particle size reach 5 - 10 μm; Purify and dry attapulgite to remove impurities and moisture therein;

[0084] (2) Mixing: Weigh activated calcium oxide, calcined calcium silicate, nano-titanium dioxide, attapulgite and additives by mass parts, add them to a high-speed mixer, and stir at a speed of 1000 r / min for 25 min to fully mix and homogenize each component to obtain a mixed material;

[0085] (3) Granulation: Add water to the mixed material to make a wet material with a water content of 18%, and then use an extrusion granulator to make the wet material into particles with a particle size of 3 - 5 mm;

[0086] (4) Drying: Dry the granulated particles at 110 °C for 3 h to remove the moisture in the particles;

[0087] (5) Calcination: Calcinate the dried particles at 700 °C for 1.5 h to cause chemical reactions between each component to form a stable composite structure, obtaining the calcium-based dry desulfurizer.

[0088] Comparative Example 6

[0089] A calcium-based dry desulfurizer, by mass parts, comprises the following components: activated calcium oxide (purity 92%, specific surface area 55 m 2 / g, average particle size 8 μm) 60 parts, calcined calcium silicate (β-Ca2SiO4, calcined at 1250 °C for 2 h, average particle size 5 μm) 10 parts, nano-titanium dioxide (purity 98%, average particle size 35 μm, anatase content 85%) 10 parts, attapulgite (specific surface area 160 m 2 / g, cation exchange capacity 120 mmol / 100 g, silicon-aluminum ratio 3) 15 parts, sodium lignosulfonate (sulfonation degree 1.5 mmol / g, molecular weight 6000) 5 parts.

[0090] A preparation method of a calcium-based dry desulfurizer, comprising the following steps:

[0091] (1) Raw material pretreatment: Grind activated calcium oxide under nitrogen conditions to make its particle size reach 5 - 10 μm; Purify and dry attapulgite to remove impurities and moisture therein;

[0092] (2) Mixing: Weigh calcium oxide, calcium silicate, nano-titanium dioxide, attapulgite, and sodium lignosulfonate by mass parts, add them to a high-speed mixer, and stir at a speed of 1000 r / min for 25 min to fully mix and homogenize each component, obtaining a mixed material.

[0093] (3) Granulation: Add water to the mixed material to make a wet material with a water content of 18%, and then use an extrusion granulator to make the wet material into granules with a particle size of 3 - 5 mm.

[0094] (4) Drying: Dry the granulated particles at 110 °C for 3 h to remove the moisture in the particles.

[0095] (5) Calcination: Calcinate the dried particles at 700 °C for 1.5 h to cause chemical reactions between each component, forming a stable composite structure, obtaining the calcium-based dry desulfurizer.

[0096] Comparative Example 7

[0097] A calcium-based dry desulfurizer, by mass parts, includes the following components: calcium oxide (purity 92%, specific surface area 55 m 2 / g, average particle size 8 μm) 60 parts, calcium silicate (β-Ca2SiO4, calcined at 1250 °C for 2 h, average particle size 5 μm) 10 parts, titanium dioxide (average particle size 10 μm) 10 parts, attapulgite (β-Ca2SiO4, calcined at 1250 °C for 2 h, average particle size 5 μm) 15 parts, sodium lignosulfonate (sulfonation degree 1.5 mmol / g, molecular weight 6000) 5 parts, additive 3 parts (lanthanum nitrate: potassium sulfate = 1:1.5, purity of lanthanum nitrate 99%, purity of potassium sulfate 98%).

[0098] A preparation method of a calcium-based dry desulfurizer, including the following steps:

[0099] (1) Raw material pretreatment: Grind calcium oxide under nitrogen conditions to make its particle size reach 5 - 10 μm; purify and dry attapulgite to remove impurities and moisture in it.

[0100] (2) Mixing: Weigh calcium oxide, calcium silicate, titanium dioxide, attapulgite, sodium lignosulfonate, and additive by mass parts, add them to a high-speed mixer, and stir at a speed of 1000 r / min for 25 min to fully mix and homogenize each component, obtaining a mixed material.

[0101] (3) Granulation: Add water to the mixed material to make a wet material with a water content of 18%, and then use an extrusion granulator to make the wet material into granules with a particle size of 3 - 5 mm.

[0102] (4) Drying: Dry the granulated particles at 110 °C for 3 h to remove the moisture in the particles;

[0103] (5) Calcination: Calcinate the dried particles at 700 °C for 1.5 h to cause chemical reactions between the components to form a stable composite structure, thereby obtaining the calcium-based dry desulfurizer.

[0104] Comparative Example 8

[0105] A calcium-based dry desulfurizer, by mass, comprises the following components: 60 parts of active calcium oxide (purity 92%, specific surface area 55 m 2 / g, average particle size 8 μm), 10 parts of calcined calcium silicate (β-Ca2SiO4, calcined at 1250 °C for 2 h, average particle size 5 μm), 10 parts of nano-titanium dioxide (purity 98%, average particle size 35 μm, anatase type content 85%), 15 parts of attapulgite (specific surface area 160 m 2 / g, cation exchange capacity 120 mmol / 100 g, silicon-aluminum ratio 3), 5 parts of sodium lignosulfonate (sulfonation degree 1.5 mmol / g, molecular weight 6000), and 3 parts of lanthanum nitrate (purity 99%).

[0106] A preparation method of a calcium-based dry desulfurizer, comprising the following steps:

[0107] (1) Raw material pretreatment: Grind the active calcium oxide under nitrogen conditions to make its particle size reach 5 - 10 μm; Purify and dry the attapulgite to remove the impurities and moisture therein;

[0108] (2) Mixing: Weigh the active calcium oxide, calcined calcium silicate, nano-titanium dioxide, attapulgite, sodium lignosulfonate, and lanthanum nitrate by mass, add them to a high-speed blender, and stir at a speed of 1000 r / min for 25 min to fully mix and homogenize the components to obtain a mixed material;

[0109] (3) Granulation: Add water to the mixed material to make a wet material with a water content of 18%, and then use an extrusion granulator to make the wet material into particles with a particle size of 3 - 5 mm;

[0110] (4) Drying: Dry the granulated particles at 110 °C for 3 h to remove the moisture in the particles;

[0111] (5) Calcination: Calcinate the dried particles at 700 °C for 1.5 h to cause chemical reactions between the components to form a stable composite structure, thereby obtaining the calcium-based dry desulfurizer.

[0112] Comparative Example 9

[0113] A calcium-based dry desulfurizer, by mass, comprises the following components: active calcium oxide (purity 92%, specific surface area 55 m 2 / g, average particle size 8 μm) 60 parts, calcined calcium silicate (β-Ca2SiO4, calcined at 1250 °C for 2 h, average particle size 5 μm) 10 parts, nano-titanium dioxide (purity 98%, average particle size 35 μm, anatase content 85%) 10 parts, attapulgite (specific surface area 160 m 2 / g, cation exchange capacity 120 mmol / 100 g, silicon-aluminum ratio 3) 15 parts, sodium lignosulfonate (sulfonation degree 1.5 mmol / g, molecular weight 6000) 5 parts, potassium sulfate (purity 98%) 3 parts.

[0114] A preparation method of the calcium-based dry desulfurizer comprises the following steps:

[0115] (1) Raw material pretreatment: Grind the active calcium oxide under nitrogen conditions to make its particle size reach 5 - 10 μm; Purify and dry the attapulgite to remove impurities and moisture therein;

[0116] (2) Mixing: Weigh the active calcium oxide, nano-titanium dioxide, calcined calcium silicate, attapulgite, sodium lignosulfonate and potassium sulfate by mass, add them to a high-speed mixer, and stir at a speed of 1000 r / min for 25 min to make each component fully mixed evenly to obtain a mixed material;

[0117] (3) Granulation: Add water to the mixed material to make a wet material with a water content of 18%, and then make the wet material into particles with a particle size of 3 - 5 mm through an extrusion granulator;

[0118] (4) Drying: Dry the granulated particles at 110 °C for 3 h to remove the moisture in the particles;

[0119] (5) Calcination: Calcinate the dried particles at 700 °C for 1.5 h to cause a chemical reaction between each component to form a stable composite structure, thereby obtaining the calcium-based dry desulfurizer.

[0120] Performance testing:

[0121] 1. Desulfurization efficiency testing: Refer to GB / T 19229.3-2022;

[0122] 2. Specific surface area testing: Refer to ISO 9277:2010;

[0123] 3. High-temperature stability testing: Refer to GB / T 1345-2005;

[0124] 4. Compressive strength testing: Refer to GB / T 1964-1996.

[0125] The test results are shown in Table 1.

[0126] Table 1 Performance test results

[0127]

[0128] It can be seen from Table 1 that the high-temperature desulfurization effect of the desulfurizer prepared in Examples 1-3 is significantly higher than that of Comparative Examples 1-9, and the high-temperature stability, specific surface area and compressive strength have also been greatly improved, indicating that the desulfurizer prepared by the present invention can be used in the desulfurization scenario of high-temperature flue gas, which has great practical significance.

[0129] The above are only the 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 principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A calcium-based dry desulfurizer, characterized in that, By mass parts, it includes the following components: 50 - 70 parts of reactive calcium oxide, 5 - 15 parts of calcined calcium silicate, 5 - 15 parts of nano-titanium dioxide, 10 - 20 parts of attapulgite, 3 - 8 parts of sodium lignosulfonate, and 2 - 5 parts of additive.

2. The calcium-based dry desulfurizer according to claim 1, wherein The calcined calcium silicate is β-Ca2SiO4, the calcination temperature is 1200 - 1400 °C, and the average particle size is 1 - 10 μm.

3. The calcium-based dry desulfurizer according to claim 1, characterized in that The additive is a mixture of lanthanum nitrate and potassium sulfate, and the mass ratio of lanthanum nitrate to potassium sulfate is 1:1 - 2. The purity of lanthanum nitrate is ≥99%, and the purity of potassium sulfate is ≥98%.

4. The calcium-based dry desulfurizer according to claim 1, characterized in that, The purity of the active calcium oxide is ≥92%, the specific surface area is ≥50 m 2 / g, and the average particle size is 5 - 10 μm.

5. The calcium-based dry desulfurizer according to claim 1, characterized in that The purity of the nano-titanium dioxide is ≥98%, the particle size range is 20 - 50 nm, and the anatase type content is ≥85%.

6. The calcium-based dry desulfurizer according to claim 1, wherein The specific surface area of the attapulgite clay ≥ 150 m 2 / g, the cation exchange capacity ≥ 100 mmol / 100 g, and the silica-alumina ratio is 2.5 - 3.

5.

7. The calcium-based dry desulfurizer according to claim 1, wherein The sulfonation degree of the sodium lignosulfonate is 1.2 - 1.8 mmol / g, and the molecular weight is 3000 - 8000.

8. A preparation method of the calcium-based dry desulfurizer according to any one of claims 1-7, characterized in that, It includes the following steps: (1) Raw material pretreatment: Grind the reactive calcium oxide to make its particle size reach 5 - 10 μm; purify and dry the attapulgite to remove impurities and moisture therein. (2) Mixing: Weigh the reactive calcium oxide, calcined calcium silicate, nano-titanium dioxide, attapulgite, sodium lignosulfonate, and additive by mass parts, add them to a high-speed mixer, and stir at a speed of 800 - 1200 r / min for 20 - 30 min to make each component fully mixed evenly to obtain a mixed material. (3) Granulation: Add water to the mixed material to make a wet material with a water content of 15 - 20%, and then use an extrusion granulator to make the wet material into particles with a particle size of 3 - 5 mm. (4) Drying: Dry the granulated particles at 100 - 120 °C for 2 - 4 h to remove the moisture in the particles. (5) Calcination: Calcinate the dried particles at 600 - 800 °C for 1 - 2 h to cause chemical reactions between each component to form a stable composite structure, and obtain the calcium-based dry desulfurizer.

9. The preparation method of the calcium-based dry desulfurizer according to claim 8, wherein, In step (1), the grinding treatment is carried out under an inert gas condition.

10. Application of a calcium-based dry desulfurizer according to any one of claims 1 - 7 in flue gas desulfurization.

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