High-solid-content slurry adaptive desulfurization enhancer and preparation method thereof

Abstract

The invention relates to the technical field of wet flue gas desulfurization, and discloses a high-solid-content slurry adaptive desulfurization enhancer and a preparation method thereof.The enhancer is formed by compounding 10%-28% of a ternary composite organic acid component, 2%-8% of an auxiliary synergistic component and 64%-88% of a carrier; the ternary composite organic acid component is formed by compounding citric acid, polycarboxylic acid copolymer and unsaturated carboxylic acid anhydride substance according to the weight ratio of 1: 1: 1-1: 3: 2, the polycarboxylic acid copolymer is of an HPEG / TPEG / APEG grafted main chain-side chain structure, and the preparation method comprises the following steps: stirring the carrier at constant temperature, sequentially adding the citric acid, the polycarboxylic acid copolymer and the unsaturated carboxylic acid anhydride substance for constant-temperature fusion, and stirring at constant temperature to obtain the ternary composite organic acid. When in use, the auxiliary synergistic components are added according to the weight of 6.5-7.5 per mill of limestone slurry, and the auxiliary synergistic components are premixed with 25-35% of solid-content slurry and then introduced into a desulfurizing tower. The desulfurization efficiency is greater than or equal to 99.2%, the settling rate of the slurry after standing for 2 hours is less than or equal to 10%, the limestone consumption is saved by 12-18%, the existing system does not need to be transformed, secondary pollution is avoided, and the method is suitable for a limestone-gypsum process high-solid-content slurry desulfurization scene.

Description

Technical Field

[0002] This invention relates to the field of wet flue gas desulfurization technology, specifically to a high-solids-content slurry-adapted desulfurization enhancer and its preparation method. Background Technology

[0003] The limestone-gypsum method is currently the mainstream process for industrial flue gas desulfurization, with advantages such as mature technology, large processing capacity, and stable desulfurization effect. It is widely used in industries such as thermal power, metallurgy, and building materials. However, in order to improve flue gas treatment efficiency, high-solids limestone slurry (25%-35% solids content) is often used in industrial production for desulfurization operations. However, high-solids slurry is prone to particle agglomeration and sedimentation, which leads to a decrease in limestone dissolution rate and gas-liquid contact efficiency. This not only limits desulfurization performance but also easily causes blockage of desulfurization towers and slurry conveying pipelines, increasing equipment operating energy consumption and maintenance costs. At the same time, existing processes often maintain the optimal pH range (5.5-6.5) for desulfurization reaction by adding excessive amounts of limestone, resulting in serious waste of limestone raw materials. Moreover, pH fluctuations in the slurry affect desulfurization efficiency. In addition, existing desulfurization enhancers have the problems of single function and poor synergy, making it difficult to adapt to high-solids conditions. Summary of the Invention

[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a high-solids-content slurry-adapted desulfurization enhancer and its preparation method. It has advantages such as improving the stability of high-solids-content slurry, reducing the amount of limestone raw materials used, and reducing overall energy consumption. It solves the problems of existing desulfurization enhancers having single functions and poor synergy, as well as poor dispersibility, large pH fluctuations, and raw material waste in the desulfurization process of high-solids-content slurry.

[0005] (II) Technical Solution To achieve the above-mentioned goals of improving the stability of high-solids slurry and reducing the amount of limestone raw materials used, the present invention provides the following technical solution: a high-solids slurry-adapted desulfurization enhancer and its preparation method, wherein the enhancer is composed of the following components by weight percentage: 10%-28% ternary composite organic acid component, 2%-8% auxiliary synergistic component, and 64%-88% carrier; The ternary composite organic acid component is composed of citric acid, polycarboxylic acid copolymers and unsaturated carboxylic anhydrides in a weight ratio of 1:1:1 to 1:3:2. The citric acid-like substance is citric acid or trisodium citrate, and its purity is ≥98%. The polycarboxylic acid copolymer is formed by polymerizing unsaturated carboxylic acid monomers to form the main chain, and grafting at least one polyether macromonomer among HPEG, TPEG, and APEG to form the side chain. The unsaturated carboxylic anhydride is maleic anhydride or itaconic anhydride, and its purity is ≥99%.

[0006] Preferably, the unsaturated carboxylic acid monomer is at least one of acrylic acid, methacrylic acid, and maleic anhydride.

[0007] Preferably, the polycarboxylic acid copolymer has a solid content of ≥40% and a molecular weight of 5000-50000 Da.

[0008] Preferably, the auxiliary synergistic component is ethylene glycol or a nonionic surfactant.

[0009] Preferably, the carrier is industrial-grade deionized water or low-impurity industrial wastewater.

[0010] Includes the following steps: ① Take the carrier according to the ratio and place it in the reaction vessel. Control the temperature at 30-55℃ and adjust the stirring speed to 150-250r / min; ② Add citric acid to the carrier from step ①, stir for 15-20 minutes until completely dissolved, and adjust the pH of the system to 5.0-6.0; ③ Add polycarboxylic acid copolymer and unsaturated carboxylic anhydride to the system in step ② in sequence, and stir at a constant temperature for 40-60 minutes to fully integrate the components; ④ Add auxiliary synergistic components to the system in step ③, continue stirring for 20-30 minutes, and cool to room temperature to obtain the high solids content slurry-adapted desulfurization enhancer product.

[0011] (III) Beneficial Effects Compared with the prior art, the present invention provides a high-solids-content slurry-adapted desulfurization enhancer and its preparation method, which has the following beneficial effects: 1. Superior Dispersion Performance and Durability: The polycarboxylic acid copolymer with HPEG / TPEG / APEG grafted structure has a much better spatial extension and hydrophilicity of side chains than traditional polycarboxylic acids. The steric hindrance effect is significant, which can effectively inhibit the agglomeration and sedimentation of limestone particles in high solids slurry. The sedimentation rate of the slurry after standing for 2 hours is ≤10%, which is 18%-28% lower than the blank group without reinforcing agent. It effectively alleviates the clogging problem of desulfurization tower and slurry conveying pipeline, reduces slurry conveying energy consumption by 10%-15%, and the slurry dispersion performance decay rate is ≤5% after 48 hours of continuous operation, with excellent long-term dispersion stability.

[0012] 2. Maximizing desulfurization efficiency to meet ultra-low emission requirements: The synergistic effect of the ternary composite organic acid system increases the desulfurization efficiency from approximately 95% of existing processes to over 99.2%, stably meeting the ultra-low SO2 emission requirements for industrial flue gas (≤35mg / m³). 3 Meanwhile, the desulfurization reaction rate is increased by 25%-35%, significantly improving flue gas treatment efficiency.

[0013] 3. Significantly reduced overall operating costs and excellent economic performance: The ternary system synergistically promotes limestone dissolution, saving limestone raw material consumption by 12%-18% and greatly reducing raw material waste; polyether macromonomers and organic acid raw materials are widely available and inexpensive, and the preparation cost of the reinforcing agent itself is reduced by 10%-15% compared with existing commercial desulfurization reinforcing agents, thus reducing the overall operating cost of the desulfurization system by 15%-20%.

[0014] 4. Excellent adaptability to working conditions and environmental friendliness, with strong practicality: It can be directly applied to existing limestone-gypsum desulfurization systems without equipment modification, and is compatible with high-solids limestone slurries with a full range of 25%-35%, making it suitable for a wide range of scenarios; the reinforcing agent formula is free of heavy metals and toxic residues, and does not affect the purity of the by-product gypsum during the desulfurization process (gypsum purity ≥95%), with no secondary pollution, in line with national environmental protection policy guidelines; the preparation process is simple, industrial-scale mass production is easy, and application and operation are convenient, combining practicality and scalability. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0016] The high-solids-content slurry-adapted desulfurization enhancer of the present invention is compounded from a ternary composite organic acid component, an auxiliary synergistic component, and a carrier in a specific weight percentage. The weight percentage of each component is as follows: Ternary compound organic acid components: 10%-28%; Auxiliary and synergistic components: 2%-8%; Carrier: 64%-88%.

[0017] The ternary composite organic acid component is composed of citric acid, polycarboxylic acid copolymers, and unsaturated carboxylic anhydrides in a weight ratio of 1:1:1 to 1:3:2. These three components complement each other, achieving a synergistic effect of dispersion stabilization and desulfurization efficiency improvement. The requirements and functions of each sub-component are as follows: Citric acid-based substances: Citric acid or trisodium citrate with a purity of ≥98% are selected, accounting for 3%-8% of the weight in the reinforcing agent. The core function is to slow down the hydrolysis rate of unsaturated carboxylic anhydrides and prolong their effective action time. At the same time, it destroys the passivation film on the surface of limestone particles through complexation, accelerates the dissolution of limestone, and provides sufficient active components for the desulfurization reaction.

[0018] Polycarboxylic acid copolymers: accounting for 3%-12% by weight in the reinforcing agent, adopting a main chain-side-linked molecular structure, with the main chain formed by the polymerization of unsaturated carboxylic acid monomers, and the side chains formed by grafting with at least one polyether macromonomer from HPEG, TPEG, and APEG. Among them, the unsaturated carboxylic acid monomers are at least one from acrylic acid, methacrylic acid, and maleic anhydride. The solid content of the polycarboxylic acid copolymers is ≥40%, and the molecular weight is controlled between 5000-50000 Da. The HPEG / TPEG / APEG polyether macromonomers have excellent hydrophilicity and spatial extensibility. The side chains formed after grafting can build a strong three-dimensional barrier on the surface of limestone particles. The main chain anchors the surface of limestone particles through carboxyl groups, effectively preventing particle agglomeration. It can still maintain long-term dispersion stability in high solid content and high salinity slurries, providing sufficient reaction area for gas-liquid contact.

[0019] Unsaturated carboxylic anhydrides: maleic anhydride or itaconic anhydride with a purity ≥99% are selected, accounting for 3%-10% by weight in the enhancer. Their core function is to enhance the adsorption and capture of SO2 in flue gas through the strong affinity of carboxyl groups for SO2; at the same time, they promote the oxidation of sulfite to sulfate. Within the optimal pH range of 5.5-6.5, they can maximize the desulfurization reaction rate and conversion rate, ensuring stable and compliant desulfurization performance.

[0020] Auxiliary synergistic components: Ethylene glycol or nonionic surfactants are selected, accounting for 2%-8% by weight in the reinforcing agent. The core function is to improve the solubility and compatibility of the ternary composite organic acid components in the carrier, strengthen the synergistic effect among the three; at the same time, it avoids affecting the purity of the desulfurization by-product gypsum, enhances the anti-interference ability of the slurry, and ensures the stable operation of the desulfurization system.

[0021] Example 1 Components and proportions (by weight percentage) Citric acid (99% purity) 5%, polycarboxylic acid copolymer (main chain: acrylic acid-maleic anhydride copolymer, side chain: HPEG, solid content 45%, molecular weight 20000Da) 8%, maleic anhydride (99% purity) 6%, ethylene glycol 3%, deionized water 78%; wherein the weight ratio of the ternary composite organic acid components is 5:8:6=1:1.6:1.2, which is within the range of 1:1:1-1:3:2 defined in this invention, and the total proportion of the ternary composite organic acid components is 19%.

[0022] Preparation process ① Place 78 portions of deionized water in a reaction vessel, control the reaction temperature at 45℃, and adjust the stirring speed to 200 r / min; ② Add 5 parts citric acid and stir continuously for 18 minutes until completely dissolved, then adjust the pH of the system to 5.5; ③ Add 8 parts of polycarboxylic acid copolymer and 6 parts of maleic anhydride in sequence, and stir at a constant temperature of 45°C for 50 minutes to ensure that the components are fully mixed; ④ Add 3 parts of ethylene glycol, continue stirring for 25 minutes, and cool to room temperature to obtain the desulfurization enhancer product.

[0023] Application conditions The above-mentioned finished product was added at 7.0‰ of the weight of the limestone slurry, and premixed with the limestone slurry with an initial solid content of 30% for 12 minutes before being introduced into the desulfurization tower; the simulated initial SO2 concentration in the flue gas was 2000 mg / m³. 3 The slurry circulation rate is 20L / h.

[0024] Performance test results The desulfurization efficiency reached 99.5%, the slurry pH was stable within the optimal range of 5.7-6.3, the slurry sedimentation rate was 8.7% after standing for 2 hours, the limestone consumption was reduced by 16%, the purity of the desulfurization by-product gypsum was 95.7%, and the slurry dispersion performance showed no significant decline after 48 hours of continuous operation.

[0025] Example 2 Components and proportions (by weight percentage) Citric acid (99% purity) 5%, polycarboxylic acid copolymer (main chain: methacrylic acid, side chain: TPEG+APEG (weight ratio 1:1), solid content 42%, molecular weight 30000Da) 12%, itaconic anhydride (99% purity) 8%, nonionic surfactant 3%, deionized water 72%; wherein the weight ratio of the ternary composite organic acid components is 5:12:8=1:2.4:1.6, which is within the range of 1:1:1-1:3:2 defined in this invention, and the total proportion of the ternary composite organic acid components is 25%.

[0026] Preparation process ① Place 72 portions of deionized water in a reaction vessel, control the reaction temperature at 50℃, and adjust the stirring speed to 220 r / min; ② Add 5 parts citric acid and stir continuously for 20 minutes until completely dissolved, then adjust the pH of the system to 5.8; ③ Add 12 parts of polycarboxylic acid copolymer and 8 parts of itaconic anhydride in sequence, and stir at a constant temperature of 50°C for 55 minutes to ensure that the components are fully mixed; ④ Add 3 parts of nonionic surfactant, continue stirring for 30 minutes, and cool to room temperature to obtain the desulfurization enhancer product.

[0027] Application conditions The above-mentioned finished product was added at 7.3‰ of the weight of the limestone slurry, and premixed with the limestone slurry with an initial solid content of 32% for 15 minutes before being introduced into the desulfurization tower; the simulated initial SO2 concentration in the flue gas was 2000 mg / m³. 3The slurry circulation rate is 20L / h.

[0028] Performance test results The desulfurization efficiency reaches 99.7%, the slurry pH is stable within the optimal range of 5.6-6.4, the slurry sedimentation rate is 8.1% after standing for 2 hours, the limestone consumption is reduced by 18%, the purity of the desulfurization by-product gypsum is 95.9%, the slurry dispersion performance decay rate is ≤5% after 48 hours of continuous operation, and the stability under high solid content conditions is excellent.

[0029] Comparative Examples To verify the synergistic advantages of the ternary composite organic acid system of this invention, four sets of comparative experiments were set up. Except for the reinforcing agent formulation, the preparation process and application conditions were kept consistent with those of Example 1. The performance test results are shown in the table below:

[0030] The comparative experimental results above show that the desulfurization enhancers prepared in Examples 1 and 2 of this invention are significantly superior to the comparative examples in terms of desulfurization efficiency, slurry pH stability, dispersion performance, raw material saving rate, and long-term durability. In particular, the HPEG / TPEG / APEG grafted polycarboxylic acid copolymer can greatly improve the slurry dispersion effect. The synergistic effect of the ternary composite organic acid system achieves dual optimization of dispersion stability and desulfurization efficiency, effectively solving the core technical defects of existing high-solids-content slurry desulfurization processes. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A desulfurization enhancing agent adapted to high solids content slurry, characterized in that: The composition consists of the following components by weight percentage: 10%-28% ternary complex organic acid component, 2%-8% auxiliary and synergistic component, and 64%-88% carrier; The ternary composite organic acid component is composed of citric acid, polycarboxylic acid copolymers and unsaturated carboxylic anhydrides in a weight ratio of 1:1:1 to 1:3:

2. The citric acid-like substance is citric acid or trisodium citrate, and its purity is ≥98%. The polycarboxylic acid copolymer is formed by polymerizing unsaturated carboxylic acid monomers to form the main chain, and grafting at least one polyether macromonomer among HPEG, TPEG, and APEG to form the side chain. The unsaturated carboxylic anhydride is maleic anhydride or itaconic anhydride, and its purity is ≥99%.

2. The high-solids-content slurry-adapted desulfurization enhancing agent according to claim 1, characterized in that: The unsaturated carboxylic acid monomer is at least one of acrylic acid, methacrylic acid, and maleic anhydride.

3. The high-solids-content slurry-adapted desulfurization enhancing agent according to claim 1, characterized in that: The polycarboxylic acid copolymer has a solid content of ≥40% and a molecular weight of 5000-50000 Da.

4. The high-solids-content slurry-adapted desulfurization enhancing agent according to claim 1, characterized in that: The auxiliary synergistic component is ethylene glycol or a nonionic surfactant.

5. The high-solids-content slurry-adapted desulfurization enhancing agent according to claim 1, characterized in that: The carrier is industrial-grade deionized water or low-impurity industrial wastewater.

6. A method for preparing a high-solids-content slurry-adapted desulfurization enhancer as described in any one of claims 1-5, characterized in that, Includes the following steps: ① Take the carrier according to the ratio and place it in the reaction vessel. Control the temperature at 30-55℃ and adjust the stirring speed to 150-250r / min; ② Add citric acid to the carrier from step ①, stir for 15-20 minutes until completely dissolved, and adjust the pH of the system to 5.0-6.0; ③ Add polycarboxylic acid copolymer and unsaturated carboxylic anhydride to the system in step ② in sequence, and stir at a constant temperature for 40-60 minutes to fully integrate the components; ④ Add auxiliary synergistic components to the system in step ③, continue stirring for 20-30 minutes, and cool to room temperature to obtain the high solids content slurry-adapted desulfurization enhancer product.

7. The preparation method of a high-solids-content slurry-adapted desulfurization enhancer according to claim 6, characterized in that: The desulfurization enhancer is added at 6.5‰-7.5‰ of the weight of the limestone slurry, and after premixing with the limestone slurry with an initial solid content of 25%-35% for 10-15 minutes, it is introduced into the desulfurization tower. During the desulfurization reaction, the pH of the slurry is controlled to be stable at 5.5-6.

5.

8. The preparation method of a high-solids-content slurry-adapted desulfurization enhancer according to claim 6, characterized in that: When the initial solid content of the limestone slurry is ≥30%, the amount of the desulfurization enhancer added is 6.8‰-7.5‰; when the initial solid content of the limestone slurry is 25%-30%, the amount of the desulfurization enhancer added is 6.5‰-7‰.

Images