Method for improving desulfurization efficiency of calcium hydroxide

Abstract

As a common atmospheric pollutant, sulfur dioxide seriously threatens the environment and human health. Calcium hydroxide is inorganic powder and has good adsorption performance on harmful gases such as sulfur dioxide. The method has the advantages of low cost, easiness in obtaining, simplicity and convenience in operation and the like, and is widely used in the industrial desulfurization process. Moreover, calcium sulfate (CaSO4) generated by reaction of calcium hydroxide and sulfur dioxide is a stable compound and can be used as a byproduct for production of building materials such as gypsum boards, resource utilization of wastes is realized, and post-treatment cost is reduced, so that improvement of the desulfurization efficiency of calcium hydroxide is particularly important. The invention provides a method capable of improving the desulfurization efficiency of calcium hydroxide, which comprises the following specific operation modes: enabling polar molecular water molecules to rapidly vibrate and generate heat by using an alternating electric field and a magnetic field for a calcium hydroxide product obtained after a digestion reaction of calcium oxide and deionized water, so as to accelerate the evaporation of water, and drying the product calcium hydroxide, so that the desulfurization efficiency of calcium hydroxide is improved. And then determining the desulfurization efficiency. Compared with calcium hydroxide which is not treated by the alternating electric field and the magnetic field, the desulfurization efficiency of the calcium hydroxide prepared by the method is improved by 41.0%.

Description

Technical Field

[0001] The present invention relates to a method for improving the desulfurization efficiency of calcium hydroxide Background Art

[0002] Sulfur dioxide, a major atmospheric pollutant, has a pungent odor and is water-soluble. When sulfur dioxide from fossil fuel combustion and automobile exhaust reacts with nitrogen oxides in the atmosphere, it produces sulfuric acid, nitric acid, and their salts. These substances then fall to the ground as rain, snow, and fog, a phenomenon known as "acid deposition." Acid rain not only poses a direct threat to human health and biological growth, but also severely damages environmental factors such as air, water quality, and soil. Therefore, reducing sulfur dioxide emissions through flue gas desulfurization (FGD) technology is crucial for improving air quality, the human living environment, and the quality of life for residents, as well as achieving sustainable development. Calcium hydroxide is an inorganic powder material primarily produced by reacting quicklime with water. Due to its unique structure and properties, it is widely used in various industries, including wastewater treatment, sugar production, coatings, and metallurgy. In FGD, calcium hydroxide is widely used to neutralize acidic substances such as sulfur dioxide, sulfur trioxide, and fluoride and chloride ions, ensuring that the sulfur content in flue gas meets environmental standards. As a commonly used desulfurization material, calcium hydroxide has been widely used in flue gas desulfurization projects due to its advantages such as easy operation, small space occupation, recyclable desulfurization by-products and no secondary pollution. Therefore, how to improve the desulfurization efficiency of calcium hydroxide is an important issue that needs to be considered at present. Yin Huagai et al. (patent document 202410830343.4) used high-purity limestone, 70-75%, amino acid 0.2-8%, surfactant 0.5-3%, nano oxide 0.5-5%, and water 10-15% to treat a highly active calcium hydroxide desulfurizer. It reduces the generation of solid waste, reduces the blue feather phenomenon, further improves the stability and durability of the desulfurizer, and achieves efficient desulfurization. Wang Ruiyi et al. (patent document 202410049255.0) mixed quicklime and amino-functionalized graphene evenly, then added water to carry out a digestion reaction to obtain a modified calcium hydroxide desulfurizer. On the one hand, it promotes the uniform dispersion of calcium hydroxide particles in the two-dimensional graphene network, inhibits the agglomeration of calcium hydroxide particles, and the silane side chains form a steric hindrance, increasing the specific surface area between calcium hydroxide particles and improving the pore size and pore volume; on the other hand, the amino functional groups on the surface of the functionalized graphene provide new high-density alkaline sites, which can synergistically strengthen the host-guest interaction, thereby improving the flue gas desulfurization efficiency. Yao Yong et al. (Preparation, Evaluation and Application Research of New Low-Carbon Emission Desulfurizer Nano Calcium Hydroxide [J]. Inorganic Salt Industry, 2023, 55(04): 38-44.) prepared a series of nano-Ca(OH)2 from CaCl2 and NaOH in the presence of PEI. It was finally concluded that the introduction of polyethyleneimine in the synthesis process of Ca(OH)2 can reduce the particle size of Ca(OH)2 and increase the specific surface area of ​​the sample. With the increase of the specific surface area of ​​Ca(OH)2, the SO2 absorption rate increases and the desulfurization efficiency is simultaneously improved.A. Garea et al. (Desulfurization yield of calcium hydroxide / fly-ash mixtures. Thermogravimetric determination [J]. Thermochimica Acta, 1996, 286(01): 173-185) added fly ash, calcium hydroxide, and water to a reactor to produce a solid desulfurizer. By calculating the solid-phase conversion rate of the desulfurizer, they obtained a conclusion similar to the maximum conversion rate of commercial Ca(OH)2. Most of the above methods for improving the desulfurization efficiency of calcium hydroxide involve mixing calcium hydroxide with other substances. The preparation process is relatively cumbersome, and some of the mixed substances used are expensive. The calcium hydroxide produced also needs to be heated and dried before being used for desulfurization. Therefore, the present invention proposes to directly react deionized water with calcium oxide and subject the resulting calcium hydroxide product to alternating electric and magnetic field treatment to improve the desulfurization efficiency of calcium hydroxide. The present invention does not require mixing with other substances or heating and drying steps, and the preparation method is relatively simple, significantly improving the desulfurization efficiency. Summary of the Invention

[0003] The object of the present invention is to provide a method for improving the desulfurization efficiency of calcium hydroxide. The existing method is to mix calcium oxide or calcium hydroxide with other substances to obtain a desulfurizer with high desulfurization efficiency. The preparation of calcium hydroxide in this way is relatively cumbersome and requires the assistance of other raw materials, and the source of other raw materials needs to be considered. The present invention directly reacts calcium oxide with deionized water to obtain a calcium hydroxide product, and then treats the obtained calcium hydroxide product with an alternating electric field and a magnetic field. This method has a simple preparation process and can significantly improve the desulfurization efficiency of calcium hydroxide compared with samples that have not been treated with an alternating electric field and a magnetic field.

[0004] The specific scheme of the present invention is:

[0005] A method for improving the desulfurization efficiency of calcium hydroxide comprises the following steps:

[0006] S1. Weigh a certain amount of calcium oxide sample, add it to a digestion reactor, and then add deionized water to carry out a digestion reaction.

[0007] S2. After the digestion reaction is completed, a portion of the product is taken and the alternating electric and magnetic fields generated by the magnetron are used to make the polar water molecules vibrate rapidly and generate heat, thereby accelerating the evaporation of water and drying the product calcium hydroxide.

[0008] S3. Desulfurization experiments are conducted on samples that have not been treated with alternating electric and magnetic fields and samples that have been treated with alternating electric and magnetic fields to characterize the desulfurization efficiency of the samples.

[0009] Furthermore, in S1, the mass ratio of deionized water to calcium oxide is 0.6-1.3.

[0010] Furthermore, in S1, the temperature of the deionized water is between 40°C and 80°C.

[0011] Furthermore, in S1, the temperature of the calcium oxide sample is between 40°C and 80°C.

[0012] Furthermore, in S1, the stirring time during the reaction is 5-10 min, and the stirring speed is between 80 rpm and 120 rpm.

[0013] Furthermore, in S2, the frequency of the alternating power plant and magnetic field treatment is set between 2250MHz-2550MHz, and the time of the alternating power plant and magnetic field treatment is between 1-4 minutes.

[0014] Furthermore, in S3, when the desulfurization experiment was carried out, the desulfurization temperature was 80 °C, the desulfurization time was 3 min, and the SO2 flow rate was 1.7×10 -3 m / s-5.0×10 -3 m / s.

[0015] Furthermore, in S3, the desulfurization efficiency is calculated as follows:

[0016]

[0017] Where η is the desulfurization efficiency, m0 is the mass of the desulfurizer, m1 is the mass before desulfurization, and m2 is the mass after desulfurization.

[0018] The positive progress effect of the present invention is:

[0019] By directly treating calcium hydroxide, the product produced by the reaction of calcium oxide with deionized water, with alternating electric and magnetic fields, the desulfurization efficiency of calcium hydroxide can be improved. This method does not require a heating or drying step. Compared with mixing calcium hydroxide with other substances to improve desulfurization efficiency, the preparation process is simpler and the improvement in calcium hydroxide desulfurization efficiency is more significant. DETAILED DESCRIPTION

[0020] The present invention is further illustrated below by way of examples, but the present invention is not limited to the scope of the examples. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be considered as equivalent replacement methods and shall be included in the scope of protection of the present invention.

[0021] Example 1

[0022] (1) Weigh 20 g of calcium oxide sample and add it to a digestion reactor, then add 12 ml of deionized water (the mass ratio of deionized water to calcium oxide is 0.6) to carry out the digestion reaction.

[0023] (2) Heat the deionized water in a water bath to 60°C

[0024] (3) Heat the calcium oxide sample in an oven to 40°C

[0025] (4) During the reaction, the stirring time was 5 min and the stirring speed was 80 rpm.

[0026] (5) A portion of the product was treated with an alternating electric field and magnetic field. The alternating electric field and magnetic field treatment frequency was set to 2550 MHz, and the alternating electric field and magnetic field treatment time was set to 1 min.

[0027] (6) Desulfurization experiment was carried out, the desulfurization temperature was set to 80℃, the desulfurization time was 3min, and the SO2 flow rate was 1.7×10 -3 m / s.

[0028] The desulfurization efficiency measured in this embodiment is 17.12%

[0029] Example 2

[0030] (1) Weigh 20 g of calcium oxide sample and add it to a digestion reactor, then add 18 ml of deionized water (the mass ratio of deionized water to calcium oxide is 0.9) to carry out the digestion reaction.

[0031] (2) Heat the deionized water in a water bath to 40°C

[0032] (3) Heat the calcium oxide sample in an oven to 70°C

[0033] (4) During the reaction, the stirring time was 7 min and the stirring speed was 100 rpm.

[0034] (5) A portion of the product was subjected to alternating electric and magnetic field treatment, the alternating electric and magnetic field treatment power was set to 2350 MHz, and the alternating electric and magnetic field treatment time was set to 2 min.

[0035] (6) Desulfurization experiment was carried out, the desulfurization temperature was set to 80℃, the desulfurization time was 3min, and the SO2 flow rate was 4.1×10 -3 m / s.

[0036] The desulfurization efficiency measured in this example is 18.42%

[0037] Example 3

[0038] (1) Weigh 20 g of calcium oxide sample and add it to a digestion reactor, then add 16 ml of deionized water (the mass ratio of deionized water to calcium oxide is 0.8) to carry out the digestion reaction.

[0039] (2) Heat the deionized water in a water bath to 70°C

[0040] (3) Heat the calcium oxide sample in an oven to 80°C

[0041] (4) During the reaction, the stirring time was 8 min and the stirring speed was 120 rpm.

[0042] (5) A portion of the product was treated with an alternating electric field and magnetic field. The alternating electric field and magnetic field treatment frequency was set to 2450 MHz, and the alternating electric field and magnetic field treatment time was set to 3 min.

[0043] (6) The desulfurization experiment was carried out, with the desulfurization temperature set to 80 °C, the desulfurization time to 3 min, and the SO2 flow rate to 3.3×10 -3 m / s.

[0044] The desulfurization efficiency measured in this example is 20.22%

[0045] Example 4

[0046] (1) Weigh 20 g of calcium oxide sample and add it to a digestion reactor, then add 26 ml of deionized water (the mass ratio of deionized water to calcium oxide is 1.3) to carry out the digestion reaction.

[0047] (2) A portion of the product was subjected to alternating electric and magnetic field treatment, wherein the alternating electric and magnetic field treatment power was set to 2250 MHz, and the alternating electric and magnetic field treatment time was set to 4 minutes.

[0048] (3) Carry out desulfurization experiment, set the desulfurization temperature to 80℃ and the desulfurization time to 3 minutes.

[0049] The desulfurization efficiency measured in this example is 19.64%

[0050] Comparative Example 1

[0051] (1) Weigh 20 g of calcium oxide sample and add it to a digestion reactor, then add 16 ml of deionized water (the mass ratio of deionized water to calcium oxide is 0.8) to carry out the digestion reaction.

[0052] (2) Heat the deionized water in a water bath to 70°C

[0053] (3) Heat the calcium oxide sample in an oven to 80°C

[0054] (4) During the reaction, the stirring time was 8 min and the stirring speed was 120 rpm.

[0055] (2) The product was not subjected to alternating electric and magnetic field treatment. After normal drying, the desulfurization experiment was carried out. The desulfurization temperature was set to 80 °C, the desulfurization time was 3 min, and the SO2 flow rate was 3.3×10 -3 m / s.

[0056] The desulfurization efficiency measured in this example is 14.34%

[0057] As shown in Examples 1-4, the desulfurization efficiency of the calcium hydroxide product after treatment with an alternating electric and magnetic field is as low as 17.12% and as high as 20.22%. As shown in Comparative Example 1, the desulfurization efficiency of the calcium hydroxide product in the desulfurization experiment after normal drying without treatment with an alternating electric and magnetic field is 14.34%. The desulfurization efficiency of the calcium hydroxide treated with an alternating electric and magnetic field is increased by up to 41.0% compared to the calcium hydroxide not treated with an alternating electric and magnetic field. Therefore, treatment with an alternating electric and magnetic field can significantly improve the desulfurization efficiency of calcium hydroxide.

Claims

1. A method for improving calcium hydroxide desulfurization efficiency, characterized in that, The following steps are involved: S1. Weigh a certain amount of calcium oxide sample, add it into a digestion reactor, then add deionized water and stir to carry out digestion reaction. S2. After the digestion reaction is completed, a portion of the product is taken and an alternating electric field and magnetic field are used to make the polar water molecules vibrate rapidly and generate heat, thereby accelerating the evaporation of water and drying the product calcium hydroxide. S3. Perform a desulfurization experiment on the sample that has not been treated with the alternating electric field and magnetic field and has been dried normally to characterize the desulfurization efficiency of the sample.

2. A method for improving calcium hydroxide desulfurization efficiency according to claim S1, characterized in that, The mass ratio of deionized water to calcium oxide is 0.6-1.

3.

3. A method for improving calcium hydroxide desulfurization efficiency according to claim S1, characterized in that, The temperature of the deionized water is between 40°C and 80°C.

4. A method for improving calcium hydroxide desulfurization efficiency according to claim S1, characterized in that, The temperature of the calcium oxide sample is between 40°C and 80°C.

5. A method for improving calcium hydroxide desulfurization efficiency according to claim S1, characterized in that, The stirring time during the reaction is 5-10 minutes, and the stirring speed is between 80 rpm and 120 rpm.

6. A method for improving calcium hydroxide desulfurization efficiency according to claim S2, characterized in that, The frequency of the alternating power plant and magnetic field treatment is set between 2250 MHz and 2550 MHz, and the time of the alternating power plant and magnetic field treatment is between 1 and 4 minutes.

7. A method for improving calcium hydroxide desulfurization efficiency according to claim S3, characterized in that, During the desulfurization experiment, the desulfurization temperature was 80℃, the desulfurization time was 3 minutes, and the SO2 flow rate was 1.7×10 -3 m / s-5.0×10 -3 m / s.

8. A method for improving calcium hydroxide desulfurization efficiency according to claim S3, characterized in that: The calculation method of desulfurization efficiency is as follows: Where η is the desulfurization efficiency, m0 is the mass of the desulfurizer, m1 is the mass before desulfurization, and m2 is the mass after desulfurization.

Images