High-strength efficient calcium-based flue gas desulfurizer and preparation method thereof

Abstract

The invention relates to the technical field of desulfurizing agents, and discloses a high-strength efficient calcium-based flue gas desulfurizing agent and a preparation method thereof.The desulfurizing agent is prepared from, by mass, 300-450 parts of slaked lime, 60-100 parts of soil and 8-40 parts of auxiliaries, and the ratio of the slaked lime to the soil to the auxiliaries is (300-450): (60-100): (8-40). The desulfurizer obtained by the invention has relatively good activity and relatively good desulfurization effect.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurizing agents, and in particular to a high-strength and high-efficiency calcium-based flue gas desulfurizing agent and a preparation method thereof. Background Art

[0002] Flue gas desulfurization (FGD) is based on chemical or physical principles to fix SO2 in flue gas into solid or solution absorbents, thereby achieving efficient removal of SO2 in flue gas. Flue gas desulfurization technology can be traced back to the middle of the 20th century. With the gradual increase in environmental awareness, countries have begun to vigorously carry out research on flue gas desulfurization technology. In the 21st century, flue gas desulfurization technology has been widely used and promoted, becoming an important means of controlling SO2 worldwide.

[0003] Flue gas desulfurization technology is mainly divided into three processes: wet, dry and semi-dry according to the form of desulfurizers and by-products. The wet process is mature and has the highest desulfurization efficiency, but the process is complex, the flue gas has a high moisture content and the by-products are difficult to handle. The semi-dry process is to react with SO2 in the flue gas during the drying process of lime slurry. Its desulfurization product is dry, but there are problems such as pipeline blockage, atomizer wear and poor atomization effect, and secondary pollution of wastewater. In the dry process, the desulfurizer and reaction products are both in dry powder form, which avoids corrosion, condensation, secondary pollution of wastewater and other problems in the flue gas desulfurization process. It is widely used in the steel industry due to its simple process system, low investment and operation costs, and high desulfurization efficiency.

[0004] Calcium-based desulfurizers are the most commonly used dry desulfurizers and are widely used in the flue gas desulfurization process. However, due to the variable flue gas emission conditions, calcium-based desulfurizers have the disadvantages of low utilization rate and insufficient low-temperature reaction activity. In addition, most calcium-based desulfurizers on the market are mainly composed of calcium hydroxide and binders, with a single component. When the calcium hydroxide content is high, the desulfurizer has low strength and is easy to pulverize; while the sulfur capacity is reduced at a low calcium hydroxide content, affecting the desulfurization effect. Therefore, through the optimization of the formula, a new type of high-strength and high-efficiency calcium-based desulfurizer for flue gas is developed, which takes into account the desulfurization efficiency, strength and cost, so that it can be widely used in various process occasions with large changes in flue gas volume. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a high-strength and high-efficiency calcium-based flue gas desulfurizer and a preparation method thereof. The desulfurizer obtained by the present invention not only has good activity and good desulfurization effect, but also has good strength and low cost.

[0006] The invention provides a high-strength and high-efficiency calcium-based flue gas desulfurizer, which comprises slaked lime, soil and an auxiliary agent. The mass ratio of the slaked lime, soil and auxiliary agent is (300 parts-450 parts): (60 parts-100 parts): (8 parts-40 parts).

[0007] Furthermore, the slaked lime is slaked lime having a mass fraction of calcium hydroxide higher than 80%.

[0008] Furthermore, the soil includes one or more of clay, bentonite, kaolin, attapulgite, diatomaceous earth, sepiolite and fly ash.

[0009] Furthermore, the auxiliary agent includes one or more of calcium carbonate, acrylic acid, sodium stearate, polyvinyl alcohol, polyacrylamide, cellulose, sodium bicarbonate, magnesium oxide, carbide slag, electrolytic manganese dioxide, iron oxide, sucrose and alum.

[0010] The present invention also provides a method for preparing the high-strength and high-efficiency calcium-based flue gas desulfurizer, the method comprising: S1: Grind and mix slaked lime and soil evenly, and dry them; S2: mixing the dried product in S1 with an auxiliary agent to obtain an intermediate product; S3: The intermediate product is stirred and kneaded with water, and then dried to obtain a high-strength and high-efficiency calcium-based flue gas desulfurizer.

[0011] Furthermore, the drying temperature in S1 is 160° C.-200° C., and the drying time is 1.5 h-2.5 h.

[0012] Furthermore, based on mass, the ratio of water to the auxiliary agent is (110 parts-170 parts):(8 parts-40 parts).

[0013] Furthermore, the slaked lime is slaked lime having a mass fraction of calcium hydroxide higher than 80%.

[0014] Furthermore, the soil includes one or more of clay, bentonite, kaolin, attapulgite, diatomaceous earth, sepiolite and fly ash.

[0015] Furthermore, the auxiliary agent includes one or more of calcium carbonate, acrylic acid, sodium stearate, polyvinyl alcohol, polyacrylamide, cellulose, sodium bicarbonate, magnesium oxide, carbide slag, electrolytic manganese dioxide, iron oxide, sucrose and alum.

[0016] Furthermore, based on mass, the ratio of slaked lime, calcium carbonate and auxiliary agent is (300 parts-450 parts):(60 parts-100 parts):(8 parts-40 parts).

[0017] Furthermore, the drying temperature in S3 is 120° C.-200° C., and the drying time is 20 min-50 min.

[0018] Furthermore, the high-strength and high-efficiency calcium-based flue gas desulfurizer is a cylindrical or four-leaf clover-shaped solid strip with a diameter of 4mm-7mm.

[0019] The embodiments of the present invention have the following technical effects: 1. In the present invention, soil is used as a raw material in the desulfurization adsorbent. First, soil has an adsorption effect. Since soil has a special microstructure and porosity, and the metal oxides contained in the soil can react with sulfur dioxide, and the soil is mainly composed of aluminosilicate minerals, using soil as an adsorbent can enhance the adsorption of sulfur dioxide with the cooperation of other raw materials. In addition, the desulfurizer containing soil also has a dust removal effect, thereby reducing by-products in the environment. It can be seen that adding soil as a raw material in the present invention can increase the desulfurization effect of the product, increase the product strength, and reduce costs.

[0020] 2. Through systematic screening of the types and contents of clay and additives, the strength of the desulfurizer can be improved while ensuring the desulfurization efficiency, further reducing the cost of calcium-based desulfurizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a flow chart of a method for preparing a high-strength and high-efficiency calcium-based flue gas desulfurizer provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments 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 creative work belong to the scope of protection of the present invention.

[0024] In a first aspect, some embodiments of the present invention provide a high-strength and high-efficiency calcium-based flue gas desulfurizer, which includes slaked lime, soil and additives. The ratio of slaked lime, soil and additives is (300 parts-450 parts) by mass: (60 parts-100 parts) by mass: (8 parts-40 parts) by mass.

[0025] In some embodiments, the slaked lime is slaked lime having a mass fraction of calcium hydroxide higher than 80%.

[0026] In some embodiments, the soil includes one or more of clay, bentonite, kaolin, attapulgite, diatomaceous earth, sepiolite and fly ash.

[0027] In some embodiments, the auxiliary agent includes one or more of calcium carbonate, acrylic acid, sodium stearate, polyvinyl alcohol, polyacrylamide, cellulose, sodium bicarbonate, magnesium oxide, carbide slag, electrolytic manganese dioxide, iron oxide, sucrose and alum.

[0028] In a second aspect, some embodiments of the present invention further provide a method for preparing the high-strength and high-efficiency calcium-based flue gas desulfurizer, the method comprising: S1: Grind and mix slaked lime and soil evenly, and dry them; S2: mixing the dried product in S1 with an auxiliary agent to obtain an intermediate product; S3: The intermediate product is stirred and kneaded with water, and then dried to obtain a high-strength and high-efficiency calcium-based flue gas desulfurizer.

[0029] In some embodiments, the drying temperature in S1 is 160° C.-200° C., and the drying time is 1.5 h-2.5 h.

[0030] In some embodiments, the ratio of water to auxiliary agent is (110 parts-170 parts) : (8 parts-40 parts) by mass.

[0031] In some embodiments, the slaked lime is slaked lime having a mass fraction of calcium hydroxide higher than 80%.

[0032] In some embodiments, the soil includes one or more of clay, bentonite, kaolin, attapulgite, diatomaceous earth, sepiolite and fly ash.

[0033] In some embodiments, the auxiliary agent includes one or more of calcium carbonate, acrylic acid, sodium stearate, polyvinyl alcohol, polyacrylamide, cellulose, sodium bicarbonate, magnesium oxide, carbide slag, electrolytic manganese dioxide, iron oxide, sucrose and alum.

[0034] In some embodiments, the ratio of slaked lime, soil and additive is (300 parts-450 parts) : (60 parts-100 parts) : (8 parts-40 parts) by mass.

[0035] In some embodiments, the drying temperature in S3 is 120° C.-200° C., and the drying time is 20 min-50 min.

[0036] In some embodiments, the high-strength and high-efficiency calcium-based flue gas desulfurizer is a cylindrical or four-leaf clover-shaped solid strip with a diameter of 4mm-7mm.

[0037] The following is described in conjunction with specific embodiments: The preparation method of the embodiment of the present invention is as follows Figure 1 shown.

[0038] Embodiment 1: After fully grinding slaked lime (calcium hydroxide content of more than 80%) and bentonite and clay (mass ratio of 3:7), dry them at 180°C for 2 hours; mix the mixed product with an auxiliary agent to obtain an intermediate product; add a corresponding amount of water for stirring and kneading, stir and knead for 20-30 minutes, extrude the product into a cylindrical or four-leaf clover-shaped solid strip with a diameter of 4-7mm by an extruder, and dry it at 160°C for 50 minutes to obtain a calcium-based desulfurizer product with calcium-based soil as the main adsorbent, and its water content is controlled at 0-6%. The auxiliary agents include calcium carbonate, magnesium oxide, iron oxide and polyvinyl alcohol. In terms of mass, the ratio of slaked lime, soil (bentonite and clay), calcium carbonate, magnesium oxide, iron oxide and polyvinyl alcohol is 350:80:7.2:3.5:1.5:2.3. The mass ratio of water to auxiliary agent is 132:14.

[0039] Embodiment 2: After fully grinding slaked lime (calcium hydroxide content of more than 80%) and clay, kaolin and sepiolite (the mass ratio of clay, kaolin and sepiolite is 6:3:1), the mixture is dried at 180°C for 2 hours; the mixed product is mixed with an auxiliary agent to obtain an intermediate product; a corresponding amount of water is added for stirring and kneading, and after stirring and kneading for 20-30 minutes, the product is extruded by an extruder to obtain a cylindrical or four-leaf clover-shaped solid strip with a diameter of 4-7mm, and dried at 160°C for 50 minutes to obtain a calcium-based desulfurizer product with calcium-based soil as the main adsorbent, and its water content is controlled at 0-6%. The auxiliary agents include calcium carbonate, magnesium oxide, electrolytic manganese dioxide and cellulose. In terms of mass, the ratio of slaked lime, soil (clay, kaolin and sepiolite), calcium carbonate, magnesium oxide, electrolytic manganese dioxide and cellulose is 350:80:6.5:3.5:2.5:2.5. The mass ratio of water to additives is 132:14.

[0040] Comparative Example 1: The zinc oxide desulfurizer used is produced by Henan Chunlin Purification Materials Co., Ltd.

[0041] The following examples and comparative examples were tested: (1) Radial strength test: refer to the standard "HG / T2782-2011 Determination of crushing resistance of fertilizer catalyst particles".

[0042] (2) Test of desulfurization effect: The experiment used sulfur dioxide standard gas with a sulfur dioxide content of 450-500 mg / m³, and used the SUV-100 flue gas analyzer produced by Shandong Xinze Instrument Co., Ltd.

[0043] Results and Analysis: Table 1 Radial strength test results of embodiments and comparative examples

[0044] Table 2 Desulfurization effect test of examples and comparative examples

[0045] The performance of the desulfurizer obtained by selecting the auxiliary agent and soil of the present invention can be adjusted. For example, by adding soil and auxiliary agents, not only the desulfurization performance and strength of the desulfurizer can be improved, but also the cost of the desulfurizer can be reduced. The desulfurizer obtained by the embodiment of the present invention has not only better strength than the comparative example, but also better desulfurization effect.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength and high-efficiency calcium-based flue gas desulfurizer, characterized in that: The desulfurizer includes slaked lime, soil and an auxiliary agent. The ratio of slaked lime, soil and the auxiliary agent is (300 parts-450 parts) : (60 parts-100 parts) : (8 parts-40 parts) by mass.

2. The high-strength and high-efficiency calcium-based flue gas desulfurizer according to claim 1, characterized in that: The slaked lime is slaked lime with a mass fraction of calcium hydroxide higher than 80%.

3. The high-strength and high-efficiency calcium-based flue gas desulfurizer according to claim 1, characterized in that: The soil includes one or more of clay, bentonite, kaolin, attapulgite, diatomaceous earth, sepiolite and fly ash.

4. The high-strength and high-efficiency calcium-based flue gas desulfurizer according to claim 1, characterized in that: The auxiliary agent includes one or more of calcium carbonate, acrylic acid, sodium stearate, polyvinyl alcohol, polyacrylamide, cellulose, sodium bicarbonate, magnesium oxide, carbide slag, electrolytic manganese dioxide, iron oxide, sucrose and alum.

5. The method for preparing the high-strength and high-efficiency calcium-based flue gas desulfurizer according to any one of claims 1 to 4, characterized in that: The preparation method comprises: S1: Grind and mix slaked lime and soil evenly, and dry them; S2: mixing the dried product in S1 with an auxiliary agent to obtain an intermediate product; S3: The intermediate product is stirred and kneaded with water, and then dried to obtain a high-strength and high-efficiency calcium-based flue gas desulfurizer.

6. The preparation method according to claim 5, characterized in that: The drying temperature in S1 is 160°C-200°C, and the drying time is 1.5h-2.5h.

7. The preparation method according to claim 5, characterized in that: In terms of mass, the ratio of water to the auxiliary agent is (110 parts-170 parts):(8 parts-40 parts).

8. The preparation method according to claim 5, characterized in that: The drying temperature in S3 is 120°C-200°C, and the drying time is 20min-50min.

9. The preparation method according to claim 5, characterized in that: The high-strength and high-efficiency calcium-based flue gas desulfurizer is a cylindrical or four-leaf clover-shaped solid strip with a diameter of 4mm-7mm.

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