Desulfurization additive for improving efficiency of limestone-gypsum flue gas desulfurization

Abstract

This invention belongs to the field of flue gas treatment technology and discloses a desulfurization additive for improving the desulfurization efficiency of limestone-gypsum flue gas desulfurization. The components include an accelerator, an activator, and a stabilizer; wherein the accelerator is a mixed dicarboxylic acid, the activator is a sulfate, and the stabilizer includes a surfactant and calcium chloride. This desulfurization additive can be formulated in proportions according to the different calcium carbonate content in the limestone, exhibiting good operational flexibility, a flexible formulation, strong adaptability, and a simple composition with low dosage, thereby improving the desulfurization efficiency of limestone slurry and enhancing the quality of gypsum.

Description

Technical Field

[0001] This invention belongs to the field of flue gas treatment technology, specifically relating to a desulfurization additive that improves the desulfurization efficiency of limestone-gypsum flue gas. Background Technology

[0002] Desulfurization additives are widely used in limestone-gypsum flue gas desulfurization processes. They can enhance liquid-phase mass transfer, improve desulfurization efficiency and desulfurizing agent utilization without modifying existing equipment. They can also prevent scaling in the desulfurization system, buffer pH fluctuations in the reaction slurry tank, increase system stability, and ultimately improve the reliability of system operation.

[0003] Currently, due to the increasingly severe environmental situation at home and abroad, as well as some problems that have arisen in the operation of the limestone-gypsum flue gas desulfurization process, many researchers at home and abroad have conducted a lot of theoretical research and experimental exploration on desulfurization additives. The research on desulfurization additives mainly focuses on three aspects: inorganic additives, organic additives, and composite additives.

[0004] CN201410112264.6 provides a composite additive composed of biomass pyrolysis carbonization vinegar, or a composite additive composed of vinegar and any one or more of organic acids, organic acid salts, inorganic metal salts, activators, and oxidants in traditional wet desulfurization additives.

[0005] CN201610591378.2 provides a desulfurization additive, comprising 1-2% red mud, 0.6-1.2% ferrite magnetic powder, 1-2% aluminum sulfate, 20-30% sodium dodecylbenzenesulfonate, 30-50% adipic acid, 0.5-1.9% catalytic oxidant, and the balance being water.

[0006] CN201410112266.5 provides a composite desulfurization additive, which is composed of biomass pyrolysis gasification tar washing liquid, or is composed of tar washing liquid and one or more of organic acids, organic acid salts, inorganic metal salts, activators, and oxidants in traditional wet desulfurization additives.

[0007] CN201310075736.0 provides a desulfurization additive and its preparation method, which consists of benzoic acid, adipic acid, sodium benzoate, sodium glycolate, sodium acetate, magnesium oxide, and magnesium sulfate.

[0008] The above patents all involve desulfurization additives for limestone-gypsum process, and their compositions are all fixed formulas, lacking flexibility and failing to consider the influence of calcium carbonate content in limestone. Summary of the Invention

[0009] To overcome the shortcomings of existing technologies, this invention provides a desulfurization additive that improves the desulfurization efficiency of limestone-gypsum flue gas. The formula ratio is adjusted according to the different calcium carbonate content in limestone, which has good operational flexibility, strong applicability, and further improves the desulfurization efficiency of limestone slurry and improves the quality of gypsum.

[0010] The above-mentioned objective of the present invention is achieved through the following technical solution: a desulfurization additive for improving the efficiency of limestone-gypsum flue gas desulfurization, comprising an accelerator, an activator and a stabilizer;

[0011] The accelerator is a mixed dicarboxylic acid, the activator is a sulfate, and the stabilizers include surfactants and calcium chloride.

[0012] The mixed dicarboxylic acid is a byproduct of the adipic acid production process. Its main components are succinic acid, glutaric acid, and adipic acid. The role of the mixed dicarboxylic acid is to effectively reduce the solid-liquid mass transfer resistance in the slurry and stabilize the pH value of the slurry, thereby improving the desulfurization efficiency of the slurry.

[0013] The activator is a sulfate, which is one or a mixture of manganese sulfate, magnesium sulfate, sodium sulfate and aluminum sulfate. The sulfate can accelerate the catalytic oxidation of calcium sulfite, a product of wet desulfurization, thereby increasing the reaction rate of the slurry and improving the quality of gypsum, a by-product of wet desulfurization.

[0014] The stabilizer is a mixture of surfactant and calcium chloride, with a mixing ratio of surfactant to calcium chloride of 1–3:1 (mass ratio). The surfactant is at least one of alkylbenzene sulfonates with a carbon chain of 10–18 carbon atoms. The stabilizer's function is to synergistically improve the SO2 absorption efficiency, enhance the desulfurization effect of the promoter and activator, and stabilize the pH value of the slurry. Simultaneously, it also improves the desulfurization and dust removal efficiency of the integrated desulfurization and dust removal unit.

[0015] The content of each component in the desulfurization additive of the present invention varies depending on the calcium carbonate content in the limestone. When the weight component content of calcium carbonate in the limestone is >95%, the weight component content of the accelerator is 60-80 parts, the weight component content of the activator is 20-30 parts, and the weight component content of the stabilizer is 5-10 parts; when the weight component content of calcium carbonate in the limestone is >94% and ≤95%, the weight component content of the accelerator is 50-70 parts, the weight component content of the activator is 20-30 parts, and the weight component content of the stabilizer is 10-30 parts; when the weight component content of calcium carbonate in the limestone is >93% and ≤94%, the weight component content of the accelerator is 40-60 parts, the weight component content of the activator is 30-40 parts, and the weight component content of the stabilizer is 10-30 parts.

[0016] Another objective of this invention is to protect the addition method of the above-mentioned desulfurization additive, specifically: the accelerator, activator and stabilizer are mixed evenly, and the mixture is taken at a weight percentage of 1 to 10‰ of the amount of limestone added, and added to the limestone slurry, with a reaction time of 1 to 4 hours.

[0017] Another objective of this invention is to protect the application of the aforementioned desulfurization additives, specifically for improving the efficiency of limestone-gypsum flue gas desulfurization.

[0018] The beneficial effects of this invention compared with the prior art are as follows: the desulfurization additive of this invention can adjust the formula ratio according to the different calcium carbonate component content in limestone, which has good operational flexibility, flexible formula, strong adaptability, simple composition, and small addition amount, thereby improving the desulfurization efficiency of limestone slurry and improving the quality of gypsum. Detailed Implementation

[0019] The present invention is described in detail below through specific embodiments, but this does not limit the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can all be obtained commercially.

[0020] Example 1

[0021] Limestone with a calcium carbonate content greater than 95% was selected to prepare a limestone slurry. 70 kg of mixed dicarboxylic acid, 20 kg of sulfate, 5 kg of sodium dodecylbenzenesulfonate, and 5 g of calcium chloride were weighed and placed in a mixer, stirred for 15 minutes to obtain a desulfurization additive. The additive was added to the limestone slurry at a weight percentage of 10‰ of the limestone content and stirred for 1–4 hours. The experimental results are listed in Table 1.

[0022] Example 2

[0023] Limestone with a calcium carbonate content greater than 95% was selected to prepare a limestone slurry. 60 kg of mixed dicarboxylic acid, 20 kg of sulfate, 10 kg of sodium dodecylbenzenesulfonate, and 10 kg of calcium chloride were weighed and placed in a mixer, stirred for 15 minutes to obtain a desulfurization additive. The additive was added to the limestone slurry at a weight percentage of 10‰ of the limestone content and stirred for 1–4 hours. The experimental results are listed in Table 1.

[0024] Example 3

[0025] Limestone with a calcium carbonate content greater than 95% was selected to prepare a limestone slurry. 50 kg of mixed dicarboxylic acid, 30 kg of sulfate, 10 kg of sodium dodecylbenzenesulfonate, and 10 kg of calcium chloride were weighed and placed in a mixer, stirred for 15 minutes to obtain a desulfurization additive. The additive was added to the limestone slurry at a weight percentage of 10‰ of the limestone content and stirred for 1–4 hours. The experimental results are listed in Table 1.

[0026] Example 4

[0027] Limestone with a calcium carbonate content of 94%-95% was selected to prepare a limestone slurry. 70 kg of mixed dicarboxylic acid, 20 kg of sulfate, 5 kg of sodium dodecylbenzenesulfonate, and 5 g of calcium chloride were weighed and placed in a mixer, stirred for 15 minutes to obtain a desulfurization additive. The additive was added to the limestone slurry at a weight percentage of 10‰ of the limestone content and stirred for 1–4 hours. The experimental results are listed in Table 1.

[0028] Example 5

[0029] Limestone with a calcium carbonate content of 94%-95% was selected to prepare a limestone slurry. 60 kg of mixed dicarboxylic acid, 20 kg of sulfate, 10 kg of sodium dodecylbenzenesulfonate, and 10 kg of calcium chloride were weighed and placed in a mixer, stirred for 15 minutes to obtain a desulfurization additive. The additive was added to the limestone slurry at a weight percentage of 10‰ of the limestone content and stirred for 1–4 hours. The experimental results are listed in Table 1.

[0030] Example 6

[0031] Limestone with a calcium carbonate content of 94%-95% was selected to prepare a limestone slurry. 50 kg of mixed dicarboxylic acid, 30 kg of sulfate, 10 kg of sodium dodecylbenzenesulfonate, and 10 kg of calcium chloride were weighed and placed in a mixer, stirred for 15 minutes to obtain a desulfurization additive. The additive was added to the limestone slurry at a weight percentage of 10‰ of the limestone content and stirred for 1–4 hours. The experimental results are listed in Table 1.

[0032] Example 7

[0033] Limestone with a calcium carbonate content of 93%-94% was selected to prepare a limestone slurry. 70 kg of mixed dicarboxylic acid, 20 kg of sulfate, 5 kg of sodium dodecylbenzenesulfonate, and 5 g of calcium chloride were weighed and placed in a mixer, stirred for 15 minutes to obtain a desulfurization additive. The additive was added to the limestone slurry at a weight percentage of 10‰ of the limestone content and stirred for 1–4 hours. The experimental results are listed in Table 1.

[0034] Example 8

[0035] Limestone with a calcium carbonate content of 93%-94% was selected to prepare a limestone slurry. 60 kg of mixed dicarboxylic acid, 20 kg of sulfate, 10 kg of sodium dodecylbenzenesulfonate, and 10 kg of calcium chloride were weighed and placed in a mixer, stirred for 15 minutes to obtain a desulfurization additive. The additive was added to the limestone slurry at a weight percentage of 10‰ of the limestone content and stirred for 1–4 hours. The experimental results are listed in Table 1.

[0036] Example 9

[0037] Limestone with a calcium carbonate content of 93%-94% was selected to prepare a limestone slurry. 50 kg of mixed dicarboxylic acid, 30 kg of sulfate, 10 kg of sodium dodecylbenzenesulfonate, and 10 kg of calcium chloride were weighed and placed in a mixer, stirred for 15 minutes to obtain a desulfurization additive. The additive was added to the limestone slurry at a weight percentage of 10‰ of the limestone content and stirred for 1–4 hours. The experimental results are listed in Table 1.

[0038] Comparative Example

[0039] Three different limestone samples with calcium carbonate contents of greater than 95%, 94-95%, and 93-94% were selected as blank samples for evaluation.

[0040] Table 1. Experimental Results

[0041]

[0042]

[0043] The embodiments described above are merely preferred embodiments of the present invention, and not all feasible embodiments of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A desulfurization additive for improving the efficiency of limestone-gypsum flue gas desulfurization, comprising a promoter, an activator and a stabilizer, characterized in that, The accelerator is a mixed dicarboxylic acid, the activator is a sulfate, and the stabilizers include surfactants and calcium chloride.

2. The desulfurization additive for improving efficiency of flue gas desulfurization according to limestone-gypsum method according to claim 1, characterized by, The mixed dicarboxylic acid is a byproduct of the adipic acid production process, and its components are succinic acid, glutaric acid, and adipic acid.

3. The desulphurization additive for improving efficiency of limestone-gypsum method flue gas desulphurization according to claim 1, characterized in that, The sulfate is one or a mixture of manganese sulfate, magnesium sulfate, sodium sulfate, and aluminum sulfate.

4. The desulfurization additive for improving efficiency of flue gas desulfurization according to claim 1, characterized by, The mixing ratio of the surfactant and calcium chloride is 1 to 3:1 by mass.

5. The desulfurization additive for improving efficiency of limestone-gypsum method flue gas desulfurization according to claim 1, characterized by, The surfactant is at least one of alkylbenzene sulfonates with a carbon chain number of 10 to 18 carbon atoms.

6. The desulphurization additive to enhance the efficiency of limestone-gypsum process flue gas desulphurization according to claim 1, characterized in that, When the calcium carbonate content in limestone is >95% by weight, the accelerator content is 60-80 parts by weight, the activator content is 20-30 parts by weight, and the stabilizer content is 5-10 parts by weight.

7. The desulphurization additive to enhance the efficiency of limestone-gypsum process flue gas desulphurization according to claim 1, characterized in that, When the calcium carbonate content in limestone is >94% and ≤95% by weight, the accelerator content is 50-70 parts by weight, the activator content is 20-30 parts by weight, and the stabilizer content is 10-30 parts by weight.

8. The desulphurization additive to enhance the efficiency of limestone-gypsum process flue gas desulphurization according to claim 1, characterized in that, When the weight composition content of calcium carbonate in limestone is >93% and ≤94%, the weight composition content of the accelerator is 40-60 parts, the weight composition content of the activator is 30-40 parts, and the weight composition content of the stabilizer is 10-30 parts.

9. A method for improving the efficiency of desulfurization of flue gas by limestone-gypsum method by adding a desulfurization additive, characterized by, Specifically, the accelerator, activator and stabilizer are mixed evenly, and then added to the limestone slurry at a weight percentage of 1 to 10‰ of the limestone addition amount. The reaction time is 1 to 4 hours.

10. The use of a desulfurization additive according to claim 1, characterized in that, Used to improve the efficiency of flue gas desulfurization using the limestone-gypsum method.

Images