Synthesis process of novel multi-component iron-based desulfurization material

Abstract

The invention provides a synthesis process of a novel multi-component iron-based desulfurization material. The raw materials comprise ferrous hydroxide suspension filtered water, a trivalent ferric salt solution, an alkali solution, a ferrite solution, an additive salt mixed solution, an oxidation catalyst solution, a bifunctional additive and cellulose. The synthesis method comprises the following synthesis steps: gradient pretreatment, generation of a ferric hydroxide flocculant through a microchannel, segmented oxygen control synthesis of ferrous hydroxide, sequential coprecipitation and introduction of a core-shell type composite additive, directional oxidation and the like. Through ultrasonic dispersion, a micro-channel reactor, nitrogen protection segmented dropwise adding, real-time infrared monitoring and other technologies, the proportion of the active component FeOOH is controlled to be 30%-70%, and a porous structure with the specific surface area larger than or equal to 250 m < 2 > / g and the average pore size being 8-15 nm is formed. The product has remarkable advantages, the sulfur capacity is more than or equal to 35% when the air speed is 3000h <-1 >, the sulfur capacity is more than or equal to 15% when the air speed is 6000h <-1 >, the method adapts to high air speed, the reaction is fast, the precision is high, and an efficient scheme is provided for industrial

Description

Technical Field

[0001] The present invention relates to the technical field of new desulfurization materials, and particularly to a synthesis process of a multi-component iron-based desulfurization new material. Background Art

[0002] Room temperature iron-based desulfurizers include iron oxide desulfurizer and iron hydroxy desulfurizer. The weight working sulfur capacity is an important indicator to measure the quality of the desulfurizer. It is detected according to the chemical industry standard HG / T4354-2012. The sulfur capacity of commercially available products is between 7-35%. The detection space velocity of this standard is 1000±50h -1 That is, the contact time between the gas to be desulfurized and the desulfurizer is 3.4-3.8 seconds. The desulfurizer particles are amorphous particles with a size of 0.85-1.18mm. In industrial use, the original particles are used, and the industrial condition space velocity is controlled at 300h -1 Hereinafter, the contact time is more than 12 seconds. Under normal use conditions, when the desulfurization accuracy is the same as the detection accuracy, the actual sulfur capacity is less than 80% of the detected sulfur capacity. When the space velocity is increased, that is, the contact time is reduced, the detected sulfur capacity gradually decreases. When the space velocity is increased to 6000h -1 (contact time 0.6s), the sulfur capacity of this type of product is almost zero. No information on the sulfur capacity that can still be detected at a space velocity of 6000h -1 was found in the public materials.

[0003] Traditional room temperature iron-based desulfurizers (such as iron oxide and iron hydroxy-based materials) have the following core problems in industrial applications: when the space velocity of traditional iron-based desulfurizers is increased to 6000h -1 , the sulfur capacity is almost zero, which cannot meet the industrial demand for high-efficiency and compact desulfurization (for example, the existing equipment is bulky due to the long contact time, and the utilization rate of the desulfurizer is low). The sulfur capacity of commercially available products is 7-35% at the standard space velocity (1000h -1 ), but in actual industrial applications, due to space velocity limitations (≤300h -1 ), the sulfur capacity is only less than 80% of the detected value, and the desulfurization accuracy is difficult to reach below 0.03mg / m 3 . The desulfurizer synthesized by the existing process has a small specific surface area, uneven pore size distribution, and uncontrollable proportion of active components (such as iron hydroxy oxide), resulting in insufficient reaction sites and low mass transfer efficiency. Summary of the Invention

[0004] The present invention provides a synthesis process of a multi-component iron-based desulfurization new material to solve the defects in the prior art.

[0005] The present invention provides a synthesis process of a multi-component iron-based desulfurization new material, including the following steps:

[0006] S1. Gradient pre-treatment stage: Add filtered water of ferrous hydroxide suspension with a mass concentration of 1%-5% into the reactor. First, disperse it with ultrasonic waves at 5-10 kHz for 10-15 min, with an ultrasonic power of 50-100 W to break the original particle aggregates. Subsequently, slowly stir at a speed of 10-20 r / min, add cellulose with a mass concentration of 0.01%-0.05%, and at the same time add a bifunctional additive accounting for 0.1%-0.5% of the total iron element mass. The bifunctional additive is composed of lignosulfonate and polyethylene glycol-400 with a mass ratio of 1:1. Control the temperature to increase from 10°C to 30°C at a rate of 2°C / min in a gradient manner to form an "ultrasonic dispersion-thickening-interface modification" composite system. Lignosulfonate improves the particle dispersibility, and polyethylene glycol-400 enhances the interfacial bonding force during subsequent molding.

[0007] S2. Microchannel-assisted generation of ferric hydroxide flocculant: Inject a ferric salt solution with a mass concentration of 10%-20% and an alkali solution with a mass concentration of 5%-15% into the bottom of the reactor through a microchannel reactor respectively. The channel diameter of the microchannel reactor is 0.5-1 mm, and the flow rate is 0.1-0.3 m / s. Utilize the high-efficiency mixing characteristics of the microchannel to make the pH value of the reaction system fluctuate dynamically within the range of 3.5-4.5 with an amplitude of ±0.2 and a fluctuation frequency of 0.5 Hz. Calculated by the mass of iron element, the addition amount of the ferric salt solution is 5 parts. After the reaction system is uniform, switch to a conventional pipeline to dropwise add the ferric salt solution until the pH value stabilizes at 5-7 to generate a ferric hydroxide flocculant with a porous network structure, whose pore diameter is 10-30 nm and specific surface area is 80-120 m 2 / g.

[0008] S3. Stepwise oxygen-controlled synthesis of ferrous hydroxide main agent: Increase the stirring speed to 20-30 r / min, introduce nitrogen into the reactor, and the nitrogen flow rate is 0.2-0.5 L / (min·L) of the reaction solution to form an inert atmosphere, and control the reaction temperature at 30-40°C. Synchronously introduce a ferrous salt solution with a mass concentration of 10%-20% and an alkali solution from the bottom of the reactor. The dropping rate of the ferrous salt solution is controlled in sections. The dropping rate in the first 30 min is 10 mL / min, and the dropping rate in the next 30 min is 5 mL / min, so that the pH value first rises rapidly to 6.0 and then slowly stabilizes at 5.5-6.5. Calculated by the mass of iron element, the addition amount of the ferrous salt solution is 80 parts to generate ferrous hydroxide solids with a concentrated particle size distribution, whose D50 is 2-5 μm, and the surface is covered with a thin oxide layer with a thickness not exceeding 5 nm to inhibit the excessive reaction in the subsequent oxidation stage.

[0009] S4. Sequential coprecipitation for introducing composite additives: Maintain the nitrogen atmosphere and stirring speed. First, add a titanium salt solution with a mass concentration of 5%-10% dropwise to the reaction solution. The titanium salt accounts for 10%-30% of the total mass of the additives. Control the pH value at 5.5-6.0 and react for 10-15 min to form nano-sized titanium hydroxyoxides with a particle size not exceeding 1 μm, which serves as the "core layer". Subsequently, add a copper / manganese mixed salt solution with a mass concentration of 5%-10% dropwise. The copper / manganese mixed salt accounts for 70%-90% of the total mass of the additives, and the molar ratio of copper to manganese is 1:2. Adjust the pH value to 7.5-8.5 and react for 20-30 min to form a "shell layer" of copper / manganese hydroxide to wrap the titanium hydroxyoxides, forming a "core-shell type" composite additive. Calculated by the mass of iron element, the total addition amount of the additive is 0.5%-3%. Finally, add a ferric salt solution dropwise to adjust the pH value to 8-10 and stabilize for 30 min.

[0010] S5. Directional oxidation stage: Continue stirring for 1-2 hours after the reaction is completed. When the pH value is stable at 8-10, add a ferric salt solution accounting for 1%-2% of the total iron element mass in the system. Subsequently, introduce air into the reaction solution at an air flow rate of 0.5-1.0 L / (min·L) of the reaction solution and conduct an oxidation reaction for 1-1.5 hours. At the same time, add an oxidation catalyst solution with a mass concentration of 5%-10%. The oxidation catalyst is a metal oxide or salt containing manganese, copper, and cobalt to promote the directional oxidation of ferrous hydroxide to form iron hydroxyoxide and inhibit the formation of iron oxide. During the oxidation process, the intensity change of the characteristic peak of iron hydroxyoxide at 1050 cm -1 is monitored in real time by infrared spectroscopy. When the intensity of this peak reaches 2-3 times the intensity of the characteristic peak of iron hydroxide at 560 cm -1 , stop ventilating.

[0011] S6. Post-treatment stage: Use a filter press with a water washing-pressing function for solid-liquid separation. Wash the solid matter repeatedly with deionized water until the mass concentration of the total soluble salts is less than 0.5%, and then press it to a moisture content of 35%-45%. Roll the mud into columnar particles with a diameter of 3-5 mm or particles with a mesh size of 20-40, and conduct oxidative drying in a hot air atmosphere at 40-110 °C, controlling the specific surface area of the dried material to be not less than 250 m 2 / g, the average pore diameter is 8-15 nm, and the pore volume is 0.4-0.6 cm 3 / g; When producing an amorphous product, directly spread the mud flat for oxidative drying and then crush it to a particle size of 0.85-1.18 mm, and obtain the finished product after screening.

[0012] According to the synthesis process of a multi-component iron-based desulfurization new material provided by the present invention, in step S1, the bifunctional additive is composed of lignosulfonate and polyethylene glycol-400 with a mass ratio of 1:1, and the addition amount is 0.1%-0.5% of the total iron element mass, which is used to improve the particle dispersibility and the forming interface bonding force simultaneously.

[0013] According to the synthesis process of a multi-component iron-based desulfurization new material provided by the present invention, in step S2, the ferric salt solution and the alkali solution are injected through a microchannel reactor. The channel diameter of the microchannel reactor is 0.5-1 mm, the flow rate is 0.1-0.3 m / s, so that the pH value of the reaction system fluctuates dynamically within the range of 3.5-4.5 with an amplitude of ±0.2, and the fluctuation frequency is 0.5 Hz. The pore diameter of the generated iron hydroxide flocculant is 10-30 nm, and the specific surface area is 80-120 m 2 / g.

[0014] According to the synthesis process of a multi-component iron-based desulfurization new material provided by the present invention, in step S3, the dropping rate of the ferrous salt solution is controlled in sections. The dropping rate in the first 30 min is 10 mL / min, and the dropping rate in the next 30 min is 5 mL / min. The D50 of the generated ferrous hydroxide solid is 2-5 μm, and its surface is covered with a thin oxide layer with a thickness of not more than 5 nm.

[0015] According to the synthesis process of a multi-component iron-based desulfurization new material provided by the present invention, in step S4, the composite additive adopts the "sequential coprecipitation" process: first, the titanium salt solution is dropped to generate a titanium hydroxyoxide "core layer" with a particle size of not more than 1 μm, and then the copper / manganese mixed salt solution is dropped to generate a "shell layer" to form a core-shell structure, where the titanium salt accounts for 10%-30% of the total mass of the additive, the copper / manganese mixed salt accounts for 70%-90%, and the molar ratio of copper to manganese is 1:2.

[0016] According to the synthesis process of a multi-component iron-based desulfurization new material provided by the present invention, in step S3, nitrogen is introduced to form an inert atmosphere. The nitrogen flow rate is 0.2-0.5 L / (min·L) of the reaction solution, and the reaction temperature is controlled at 30-40 °C to inhibit the excessive oxidation of ferrous hydroxide.

[0017] According to the synthesis process of a multi-component iron-based desulfurization new material provided by the present invention, in step S5, the oxidation catalyst solution is a manganese dioxide suspension with a mass concentration of 5%-10%, and the addition amount is 0.1%-0.5% of the total mass of the reaction system, so that the oxidation conversion rate of ferrous hydroxide is controlled at 50%-70% to form a composite structure of iron oxyhydroxide and ferrous hydroxide.

[0018] According to the synthesis process of a multi-component iron-based desulfurization new material provided by the present invention, in step S6, the specific surface area of the dried material is not less than 250 m 2 / g, with an average pore diameter of 8 - 15 nm and a pore volume of 0.4 - 0.6 cm 3 / g, achieved by the synergistic effect of the porous flocculant in step S2 and the core - shell auxiliary agent in step 4.

[0019] According to the synthesis process of a multi - component iron - based desulfurization new material provided by the present invention, the ferric salt solution is a polyferric sulfate solution, the alkali solution is a sodium hydroxide solution, and the ferrous salt solution is a ferrous sulfate solution.

[0020] According to the synthesis process of a multi - component iron - based desulfurization new material provided by the present invention, in step S1, ultrasonic dispersion is carried out at 5 - 10 kHz for 10 - 15 min, and the ultrasonic power is 50 - 100 W to break the initial aggregates of ferrous hydroxide particles.

[0021] The synthesis process of a multi - component iron - based desulfurization new material provided by the present invention realizes the directional oxidation of ferrous hydroxide to iron oxyhydroxide by adding a specific oxidation catalyst and real - time infrared spectroscopy monitoring, inhibits the formation of iron oxide, makes the proportion of iron oxyhydroxide reach 30% - 70%, and forms a highly active "iron oxyhydroxide - ferrous hydroxide" composite structure. In the oxidation reaction, the oxidation conversion rate of ferrous hydroxide is controlled at 50% - 70% through the air flow rate and the characteristic peak intensity ratio to avoid a decrease in activity caused by over - oxidation. The porous iron hydroxide flocculant is generated through a microchannel reactor and the core - shell type auxiliary agent formed by sequential coprecipitation significantly improves the number of reaction sites and the gas diffusion efficiency. In the gradient pretreatment stage, ultrasonic dispersion and a bifunctional auxiliary agent are used to improve the dispersibility of ferrous hydroxide particles; in the staged oxygen - controlled synthesis stage, a surface thin oxide layer is formed through nitrogen protection and staged dropping rates to inhibit particle agglomeration. At an airspeed of 3000 h -1 the sulfur capacity is increased, far exceeding that of existing products. The auxiliary agent adopts a "core - shell type" structure, the titanium core improves the structural stability, and the copper / manganese shell enhances the H2S adsorption and activation efficiency, forming a synergistic catalytic effect. The water - washing step removes the total soluble salts, and the liquid enters the sewage treatment system to reduce impurity residues; the forming and drying temperature is controlled at 40 - 110 °C, with low energy consumption, improved material utilization rate, and reduced equipment volume. Detailed implementation manners

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and presented usually can be arranged and designed in various different configurations.

[0023] Therefore, the detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts fall within the scope of protection of the present invention.

[0024] It should be noted that similar reference numerals and letters denote similar items. Therefore, once an item is defined, no further definition and explanation are required. In addition, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0025] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "inner", "outer", "upper", etc. is based on the shown orientation or positional relationship, or the orientation or positional relationship in which the inventive product is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present invention.

[0026] The present invention provides a synthesis process for a multi-component iron-based desulfurization new material, comprising the following steps:

[0027] S1. Gradient pretreatment stage: Add filtered water of a ferrous hydroxide suspension with a mass concentration of 1% - 5% into a reaction kettle. First, disperse it with ultrasonic waves at 5 - 10 kHz for 10 - 15 min, with an ultrasonic power of 50 - 100 W to break the original particle aggregates. Subsequently, slowly stir at a speed of 10 - 20 r / min, add cellulose with a mass concentration of 0.01% - 0.05%, and at the same time add a bifunctional auxiliary agent accounting for 0.1% - 0.5% of the total iron element mass. The bifunctional auxiliary agent is composed of lignosulfonate and polyethylene glycol - 400 with a mass ratio of 1:1. Control the temperature to rise from 10°C to 30°C at a rate of 2°C / min in a gradient manner to form an "ultrasonic dispersion - thickening - interfacial modification" composite system. Lignosulfonate improves the particle dispersibility, and polyethylene glycol - 400 enhances the interfacial bonding force during subsequent molding.

[0028] S2. Microchannel-assisted generation of ferric hydroxide flocculant: A ferric salt solution with a mass concentration of 10%-20% and an alkali solution with a mass concentration of 5%-15% are respectively injected into the bottom of the reaction kettle through a microchannel reactor. The channel diameter of the microchannel reactor is 0.5-1 mm, and the flow rate is 0.1-0.3 m / s. Utilizing the high-efficiency mixing characteristics of the microchannel, the pH value of the reaction system fluctuates dynamically within the range of 3.5-4.5 with an amplitude of ±0.2, and the fluctuation frequency is 0.5 Hz. Calculated by the mass of iron element, the addition amount of the ferric salt solution is 5 parts. After the reaction system is uniform, switch to a conventional pipeline to dropwise add the ferric salt solution until the pH value stabilizes at 5-7, generating a ferric hydroxide flocculant with a porous network structure, whose pore diameter is 10-30 nm and specific surface area is 80-120 m 2 / g.

[0029] S3. Stepwise oxygen-controlled synthesis of ferrous hydroxide main agent: Increase the stirring speed to 20-30 r / min, introduce nitrogen into the reaction kettle, and the nitrogen flow rate is 0.2-0.5 L / (min·L) of the reaction liquid to form an inert atmosphere, and control the reaction temperature at 30-40 °C; Synchronously introduce a ferrous salt solution with a mass concentration of 10%-20% and an alkali solution from the bottom of the reaction kettle. The dropping rate of the ferrous salt solution is controlled stepwise. The dropping rate in the first 30 min is 10 mL / min, and the dropping rate in the next 30 min is 5 mL / min, so that the pH value first rises rapidly to 6.0 and then slowly stabilizes at 5.5-6.5; Calculated by the mass of iron element, the addition amount of the ferrous salt solution is 80 parts, generating ferrous hydroxide solids with a concentrated particle size distribution, whose D50 is 2-5 μm, and the surface is covered with a thin oxide layer with a thickness not exceeding 5 nm to inhibit the excessive reaction in the subsequent oxidation stage.

[0030] S4. Sequential coprecipitation to introduce composite additives: Maintain the nitrogen atmosphere and stirring speed. First, dropwise add a titanium salt solution with a mass concentration of 5%-10% to the reaction liquid. The titanium salt accounts for 10%-30% of the total mass of the additives, and control the pH value at 5.5-6.0 for reaction for 10-15 min to generate nano-sized titanium hydroxyoxides with a particle size not exceeding 1 μm as the "core layer"; Subsequently, dropwise add a copper / manganese mixed salt solution with a mass concentration of 5%-10%. The copper / manganese mixed salt accounts for 70%-90% of the total mass of the additives, and the molar ratio of copper to manganese is 1:2. Adjust the pH value to 7.5-8.5 for reaction for 20-30 min to generate a "shell layer" of copper / manganese hydroxide to wrap the titanium hydroxyoxides, forming a "core-shell type" composite additive; Calculated by the mass of iron element, the total addition amount of the additives is 0.5%-3%; Finally, dropwise add a ferric salt solution to adjust the pH value to 8-10 and stabilize for 30 min.

[0031] S5. Directional Oxidation Stage: After the reaction is completed, continue stirring for 1 - 2 hours. When the pH value stabilizes at 8 - 10, add a ferric salt solution accounting for 1% - 2% of the total iron element mass in the system. Subsequently, introduce air into the reaction solution at an air flow rate of 0.5 - 1.0 L / (min·L) of the reaction solution, and conduct an oxidation reaction for 1 - 1.5 hours. Meanwhile, add an oxidation catalyst solution with a mass concentration of 5% - 10%. The oxidation catalyst is a metal oxide or salt containing manganese, copper, and cobalt, which promotes the directional oxidation of ferrous hydroxide to form iron oxyhydroxide and inhibits the formation of iron oxide. During the oxidation process, the intensity change of the characteristic peak of iron oxyhydroxide at 1050 cm -1 is monitored in real time by infrared spectroscopy. When the intensity of this peak reaches 2 - 3 times the intensity of the characteristic peak of ferric hydroxide at 560 cm -1 , stop ventilating.

[0032] S6. Post - treatment Stage: Use a filter press with water washing - pressing function for solid - liquid separation. Wash the solid matter repeatedly with deionized water until the mass concentration of soluble total salts is less than 0.5%, and then press it to a moisture content of 35% - 45%. Roll the mud into columnar particles with a diameter of 3 - 5 mm or particles of 20 - 40 mesh, and conduct oxidative drying in a hot air atmosphere at 40 - 110°C, controlling the specific surface area of the dried material to be not less than 250 m 2 / g, the average pore diameter is 8 - 15 nm, and the pore volume is 0.4 - 0.6 cm 3 / g. When producing amorphous products, spread the mud directly and conduct oxidative drying, then crush it to a particle size of 0.85 - 1.18 mm, and obtain the finished product after screening.

[0033] To further optimize the above - mentioned technical solution, the bifunctional additive in step S1 consists of lignosulfonate and polyethylene glycol - 400 with a mass ratio of 1:1, and the addition amount is 0.1% - 0.5% of the total iron element mass, which is used to improve the particle dispersibility and the bonding force at the forming interface simultaneously.

[0034] To further optimize the above - mentioned technical solution, the ferric salt solution and the alkali solution in step S2 are injected through a micro - channel reactor. The channel diameter of the micro - channel reactor is 0.5 - 1 mm, and the flow rate is 0.1 - 0.3 m / s, so that the pH value of the reaction system fluctuates dynamically within the range of 3.5 - 4.5 with an amplitude of ±0.2 and a fluctuation frequency of 0.5 Hz. The pore diameter of the generated ferric hydroxide flocculant is 10 - 30 nm, and the specific surface area is 80 - 120 m 2 / g.

[0035] To further optimize the above technical solution, the dropping rate of the ferrous salt solution in step S3 is controlled in segments. The dropping rate in the first 30 minutes is 10 mL / min, and the dropping rate in the next 30 minutes is 5 mL / min. The D50 of the generated ferrous hydroxide solid is 2 - 5 μm, and its surface is covered with a thin oxide layer with a thickness not exceeding 5 nm.

[0036] To further optimize the above technical solution, the composite auxiliary agent in step S4 adopts the "sequential co - precipitation" process: first, the titanium salt solution is dropped to generate a titanium hydroxy - oxide "core layer" with a particle size not exceeding 1 μm, and then the copper / manganese mixed salt solution is dropped to generate a "shell layer" to form a core - shell structure. Among them, the titanium salt accounts for 10% - 30% of the total mass of the auxiliary agent, the copper / manganese mixed salt accounts for 70% - 90%, and the molar ratio of copper to manganese is 1:2.

[0037] To further optimize the above technical solution, nitrogen is introduced in step S3 to form an inert atmosphere. The nitrogen flow rate is 0.2 - 0.5 L / (min·L) of the reaction solution, and the reaction temperature is controlled at 30 - 40 °C to inhibit the over - oxidation of ferrous hydroxide.

[0038] To further optimize the above technical solution, the oxidation catalyst solution in step S5 is a manganese dioxide suspension with a mass concentration of 5% - 10%, and the addition amount is 0.1% - 0.5% of the total mass of the reaction system, so that the oxidation conversion rate of ferrous hydroxide is controlled at 50% - 70% to form a composite structure of iron oxyhydroxide and ferrous hydroxide.

[0039] To further optimize the above technical solution, the specific surface area of the dried material in step S6 is not less than 250 m 2 / g, the average pore diameter is 8 - 15 nm, and the pore volume is 0.4 - 0.6 cm 3 / g, which is achieved by the synergistic effect of the porous flocculant in step S2 and the core - shell auxiliary agent in step 4.

[0040] To further optimize the above technical solution, the ferric salt solution is a polyferric sulfate solution, the alkali solution is a sodium hydroxide solution, and the ferrous salt solution is a ferrous sulfate solution.

[0041] To further optimize the above technical solution, ultrasonic dispersion is carried out at 5 - 10 kHz for 10 - 15 minutes in step S1, and the ultrasonic power is 50 - 100 W to break the initial aggregates of ferrous hydroxide particles.

[0042] To introduce the synthesis process of a multi - component iron - based desulfurization new material provided by the embodiments of the present invention more clearly and in detail, the following will be described in combination with specific embodiments.

[0043] Example 1

[0044] Raw material selection:

[0045] Ferric salt solution: A polyferric sulfate solution with a mass concentration of 15% (in terms of Fe, the iron content is 10 g / L).

[0046] Ferrous salt solution: A ferrous sulfate solution with a mass concentration of 15% (in terms of Fe, the iron content is 80 g / L).

[0047] Alkali solution: A sodium hydroxide solution with a mass concentration of 10%.

[0048] Bifunctional additive: Lignosulfonate and polyethylene glycol - 400 (mass ratio 1:1), and the addition amount is 0.3% of the total mass of iron element.

[0049] Additive salt mixed solution: A mixed solution of titanium sulfate (accounting for 20% of the total mass of the additive), copper sulfate, and manganese sulfate (molar ratio 1:2) with a total mass concentration of 8%.

[0050] Oxidation catalyst: A manganese dioxide suspension with a mass concentration of 8%, and the addition amount is 0.3% of the total mass of the reaction system.

[0051] Synthesis steps:

[0052] 1. Gradient pretreatment stage: Add filtered water (8 L) of a ferrous hydroxide suspension with a mass concentration of 3% to a 10 L reactor, turn on a 5 kHz ultrasonic wave (power 80 W) for dispersion for 12 min; then stir at 15 r / min, add cellulose (mass concentration 0.03%) and bifunctional additive (0.3% of the total mass of iron element), and control the temperature to rise from 10°C to 30°C at a gradient of 2°C / min to form a homogeneous dispersion system.

[0053] 2. Microchannel - assisted generation of iron hydroxide flocculant: Inject the polyferric sulfate solution and sodium hydroxide solution into the bottom of the reactor through a microchannel reactor (channel diameter 0.8 mm, flow rate 0.2 m / s), control the pH value to fluctuate dynamically within the range of 3.5 - 4.5 with an amplitude of ±0.2 (frequency 0.5 Hz), and the addition amount in terms of Fe is 5 parts (i.e., 0.5 L, containing 5 g of Fe); after the system is uniform, switch to dropping the polyferric sulfate solution through a conventional pipeline until pH = 6.0 to generate a porous iron hydroxide flocculant (pore diameter 15 - 25 nm, specific surface area 100 m 2 / g).

[0054] 3. Synthesis of the main agent of ferrous hydroxide by staged oxygen control: Increase the stirring speed to 25 r / min, introduce nitrogen (flow rate 0.3 L / (min·L) of the reaction solution), and control the reaction temperature at 35 °C; simultaneously drip-feed ferrous sulfate solution (drip-feed rate 10 mL / min for the first 30 min and 5 mL / min for the next 30 min) and sodium hydroxide solution, so that the pH value first rises to 6.0 (for the first 30 min) and then stabilizes at 6.0 (for the next 30 min). The addition amount is 80 parts by Fe (i.e., 8 L, containing 80 g of Fe), generating ferrous hydroxide solid with D50 = 3 μm, and a thin oxide layer with a thickness of 3 nm covers the surface.

[0055] 4. Sequential coprecipitation to introduce composite additives: Maintain the nitrogen atmosphere and stirring speed. First, drip-feed titanium sulfate solution (accounting for 20% of the total mass of the additives, mass concentration 8%), control the reaction at pH = 5.8 for 12 min to generate a "core layer" of titanium hydroxyoxide with a particle size of 0.8 μm; then drip-feed a mixed solution of copper sulfate and manganese sulfate (molar ratio 1:2, accounting for 80% of the total mass of the additives, mass concentration 8%), adjust the pH = 8.0 and react for 25 min to generate a "shell layer" of copper / manganese hydroxide to wrap the titanium hydroxyoxide, forming a core-shell type composite additive (the total addition amount is 2% by Fe, i.e., 1.6 g); finally, drip-feed polyferric sulfate solution until pH = 9.0 and stabilize for 30 min.

[0056] 5. Directional oxidation stage: Continue stirring for 1.5 hours until the pH stabilizes, add polyferric sulfate solution (accounting for 1.5% of the total mass of iron elements, i.e., 1.28 g), introduce air (flow rate 0.8 L / (min·L) of the reaction solution) and oxidize for 1.2 hours, and simultaneously add manganese dioxide suspension (0.3% of the total mass of the reaction system); monitor by infrared spectroscopy. When the intensity of the characteristic peak of iron oxyhydroxide (1050 cm -1 ) reaches 2.5 times that of the peak of ferric hydroxide (560 cm -1 ), stop ventilation, and the oxidation conversion rate is 50%.

[0057] 6. Post-treatment stage: After solid-liquid separation, wash the solid with deionized water until the total soluble salt concentration is 0.4%, and press it until the water content is 40%; roll it into φ4 mm columnar particles, and oxidize and dry it in a hot air atmosphere at 80 °C to obtain a desulfurizer with a specific surface area of 260 m 2 / g, an average pore diameter of 12 nm, and a pore volume of 0.5 cm 3 / g.

[0058] Performance test results:

[0059] Sulfur capacity at an airspeed of 3000 h -1 : 38%; sulfur capacity at an airspeed of 6000 h -1 : 18%.

[0060] Desulfurization accuracy: 0.02 mg / m3 (H2S inlet concentration 1000 mg / m 3 )。

[0061] Example 2

[0062] Raw material selection:

[0063] Ferric salt solution: Ferric nitrate solution with a mass concentration of 12% (calculated as Fe, iron content 8 g / L).

[0064] Ferrous salt solution: Ferrous chloride solution with a mass concentration of 18% (calculated as Fe, iron content 90 g / L).

[0065] Alkali solution: Ammonia water solution with a mass concentration of 12%.

[0066] Bifunctional additive: Lignosulfonate and polyethylene glycol - 400 (mass ratio 1:1), the addition amount is 0.2% of the total iron element mass.

[0067] Additive salt mixed solution: Mixed solution of titanium citrate (accounting for 25% of the total additive mass), cobalt sulfate and titanium chloride (molar ratio 1:3) (total mass concentration 6%).

[0068] Oxidation catalyst: Cobalt acetate solution with a mass concentration of 6%, the addition amount is 0.2% of the total mass of the reaction system.

[0069] Synthesis steps:

[0070] 1. Gradient pretreatment stage: Add filtered water (8 L) of ferrous hydroxide suspension with a mass concentration of 2% to a 10 L reactor, turn on an 8 kHz ultrasonic wave (power 60 W) to disperse for 15 min; then stir at 12 r / min, add cellulose (mass concentration 0.02%) and bifunctional additive (0.2% of the total iron element mass), and control the temperature to rise from 10°C to 25°C at a gradient of 2°C / min.

[0071] 2. Microchannel collaborative generation of iron hydroxide flocculant: Inject the ferric nitrate solution and ammonia water solution into the bottom of the reactor through a microchannel reactor (channel diameter 0.6 mm, flow rate 0.15 m / s), control the pH value to dynamically fluctuate within the range of 3.8 - 4.2 with an amplitude of ±0.2 (frequency 0.5 Hz), and the addition amount is 5 parts calculated as Fe (i.e., 0.625 L, containing 5 g of Fe); after the system is uniform, switch to a conventional pipeline to dropwise add the ferric nitrate solution until pH = 5.5 to generate a porous iron hydroxide flocculant (pore size 12 - 20 nm, specific surface area 90 m 2 / g).

[0072] 3. Synthesis of the main agent of ferrous hydroxide by staged oxygen control: Increase the stirring speed to 22 r / min, introduce nitrogen (flow rate 0.4 L / (min·L) of the reaction solution), and control the reaction temperature at 32 °C; simultaneously drip-feed a ferrous chloride solution (drip-feed rate 8 mL / min for the first 30 min and 4 mL / min for the next 30 min) and an ammonia water solution, so that the pH value first rises to 5.8 (for the first 30 min) and then stabilizes at 5.6 (for the next 30 min). The addition amount is 80 parts by Fe (i.e., 8.89 L, containing 80 g of Fe), generating ferrous hydroxide solid with D50 = 2.5 μm, and a thin oxide layer with a thickness of 4 nm covers the surface.

[0073] 4. Sequential coprecipitation to introduce a composite auxiliary agent: Maintain the nitrogen atmosphere and stirring speed. First, drip-feed a titanium citrate solution (accounting for 25% of the total mass of the auxiliary agent, mass concentration 6%), control the reaction at pH = 5.6 for 15 min to generate a "core layer" of titanium hydroxy oxide with a particle size of 0.6 μm; subsequently, drip-feed a mixed solution of cobalt sulfate and titanium chloride (molar ratio 1:3, accounting for 75% of the total mass of the auxiliary agent, mass concentration 6%), adjust the pH = 7.8 and react for 30 min to generate a "shell layer" of cobalt / titanium hydroxide to wrap the titanium hydroxy oxide, forming a core-shell type composite auxiliary agent (the total addition amount is 1.5% by Fe, i.e., 1.2 g); finally, drip-feed a ferric nitrate solution until pH = 8.5 and stabilize for 30 min.

[0074] 5. Directional oxidation stage: Continue stirring for 2 hours until the pH stabilizes, add a ferric nitrate solution (accounting for 1% of the total mass of iron elements, i.e., 0.8 g), introduce air (flow rate 0.6 L / (min·L) of the reaction solution) and oxidize for 1 hour, and simultaneously add a cobalt acetate solution (0.2% of the total mass of the reaction system); monitor by infrared spectroscopy. When the intensity of the characteristic peak of iron oxyhydroxide (1050 cm -1 ) reaches 2.2 times that of the peak of ferric hydroxide (560 cm -1 ), stop ventilation, and the oxidation conversion rate is 45%.

[0075] 6. Post-treatment stage: After solid-liquid separation, the solid is washed with deionized water until the total soluble salt concentration is 0.3%, and pressed until the water content is 38%; roll-pressed into 20-40 mesh particles, and oxidized and dried in a hot air atmosphere at 60 °C to obtain a desulfurizer with a specific surface area of 255 m 2 / g, an average pore diameter of 10 nm, and a pore volume of 0.45 cm 3 / g.

[0076] Performance test results:

[0077] Sulfur capacity at an airspeed of 3000 h -1 : 36%; sulfur capacity at an airspeed of 6000 h -1 : 16%.

[0078] Desulfurization accuracy: 0.025 mg / m2 (Inlet concentration of H2S is 1000 mg / m 3 ).

[0079] In Examples 1-2, different iron salts (polyaluminum ferric sulfate / ferric nitrate, ferrous sulfate / ferrous chloride) and promoter combinations (copper / manganese / titanium, cobalt / titanium) were used respectively, and multi-component iron-based desulfurizers with specific surface area ≥ 250 m 2 / g and high space velocity sulfur capacity ≥ 15% were successfully synthesized, verifying the universality and stability of the method described in the claims. By adjusting the raw materials and process parameters, the microstructure and performance of the desulfurizer can be optimized according to specific application scenarios to meet different industrial requirements.

[0080] The synthesis process of a multi-component iron-based desulfurization new material provided by the present invention realizes the directional oxidation of ferrous hydroxide to iron oxyhydroxide by adding a specific oxidation catalyst and real-time infrared spectroscopy monitoring, inhibits the formation of iron oxide, and makes the proportion of iron oxyhydroxide reach 30%-70%, forming a highly active "iron oxyhydroxide-ferrous hydroxide" composite structure. In the oxidation reaction, the oxidation conversion rate of ferrous hydroxide is controlled at 50%-70% by the air flow rate and the intensity ratio of characteristic peaks to avoid the decrease in activity caused by over-oxidation. The formation of porous iron hydroxide flocculant and core-shell type promoter formed by sequential coprecipitation through a microchannel reactor significantly improves the number of reaction sites and gas diffusion efficiency. In the gradient pretreatment stage, ultrasonic dispersion and bifunctional promoter are used to improve the dispersibility of ferrous hydroxide particles; in the staged oxygen control synthesis stage, a thin surface oxide layer is formed by nitrogen protection and staged dropping rate to inhibit particle agglomeration. At a space velocity of 3000 h -1 , the sulfur capacity is improved, far exceeding that of existing products. The promoter adopts a "core-shell" structure, with a titanium core enhancing the structural stability and a copper / manganese shell enhancing the H2S adsorption and activation efficiency, forming a synergistic catalytic effect. The washing step removes the total soluble salts, and the liquid enters the sewage treatment system to reduce impurity residues; the forming and drying temperature is controlled at 40-110 °C, with low energy consumption, improved material utilization rate, and reduced equipment volume.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A synthesis process of a new multi-component iron-based desulfurization material, characterized in that: The following steps are involved: S1, gradient pretreatment stage: add filtered water of ferrous hydroxide suspension with a mass concentration of 1%-5% into the reactor, first disperse with 5-10kHz ultrasonic wave for 10-15min, and the ultrasonic power is 50-100W to destroy the original particle agglomerates; then slowly stir at a speed of 10-20r / min, add cellulose, the cellulose mass concentration is 0.01%-0.05%, and at the same time add a bifunctional additive accounting for 0.1%-0.5% of the total iron element mass, the bifunctional additive is composed of lignin sulfonate and polyethylene glycol-400 with a mass ratio of 1:1; control the temperature to rise from 10℃ to 30℃ at a rate of 2℃ / min, to form an "ultrasonic dispersion-thickening-interface modification" composite system, lignin sulfonate improves the dispersibility of particles, and polyethylene glycol-400 improves the interfacial bonding force during subsequent molding. S2. Microchannel synergistically generates ferric hydroxide flocculant: a 10%-20% ferric salt solution and a 5%-15% alkaline solution are respectively injected into the bottom of the reactor through a microchannel reactor. The channel diameter of the microchannel reactor is 0.5-1mm, and the flow rate is 0.1-0.3m / s. The efficient mixing characteristics of the microchannel are utilized to make the pH value of the reaction system dynamically fluctuate within the range of 3.5-4.5 with an amplitude of ±0.2, and the fluctuation frequency is 0.5Hz; the amount of ferric salt solution added is 5 parts based on the mass of the iron element; after the reaction system is uniform, switch to a conventional pipeline to drip the ferric salt solution until the pH value stabilizes at 5-7, thereby generating a ferric hydroxide flocculant with a porous network structure, the pore size of which is 10-30nm and the specific surface area of ​​which is 80-120m 2 / g. S3, synthesizing ferrous hydroxide main agent by staged oxygen control: increasing the stirring speed to 20-30r / min, introducing nitrogen into the reactor, the nitrogen flow rate is 0.2-0.5L / (min·L) reaction liquid, forming an inert atmosphere, and controlling the reaction temperature at 30-40°C; introducing ferrous salt solution and alkaline solution with a mass concentration of 10%-20% from the bottom of the reactor simultaneously, the dripping rate of the ferrous salt solution is staged controlled, the dripping rate in the first 30min is 10mL / min, and the dripping rate in the next 30min is 5mL / min, so that the pH value first rises rapidly to 6.0, and then slowly stabilizes at 5.5-6.5; the amount of ferrous salt solution added is 80 parts by weight of iron element, and ferrous hydroxide solid with concentrated particle size distribution is generated, and its D50 is 2-5μm, and the surface is covered with a thin oxide layer with a thickness of no more than 5nm, which inhibits excessive reaction in the subsequent oxidation stage. S4. Introduce composite additives by sequential coprecipitation: maintain nitrogen atmosphere and stirring speed, first add a titanium salt solution with a mass concentration of 5%-10% to the reaction liquid, the titanium salt accounts for 10%-30% of the total mass of the additive, control the pH value at 5.5-6.0 and react for 10-15 minutes to generate nano-scale titanium hydroxide oxide, the particle size of which does not exceed 1μm, as a "core layer"; then add a copper / manganese mixed salt solution with a mass concentration of 5%-10%, the copper / manganese mixed salt accounts for 70%-90% of the total mass of the additive, the molar ratio of copper to manganese is 1:2, adjust the pH value to 7.5-8.5 and react for 20-30 minutes to generate a copper / manganese hydroxide "shell layer" to wrap the titanium hydroxide oxide, forming a "core-shell type" composite additive; based on the mass of iron element, the total amount of additive added is 0.5%-3%; finally, add a trivalent iron salt solution to adjust the pH value to 8-10 and stabilize for 30 minutes. S5, directional oxidation stage: after the reaction is completed, stirring is continued for 1-2 hours. When the pH value is stabilized at 8-10, a trivalent iron salt solution accounting for 1%-2% of the total iron element in the system is added, and then air is introduced into the reaction solution at an air flow rate of 0.5-1.0L / (min·L) of the reaction solution, and the oxidation reaction is carried out for 1-1.5 hours; at the same time, an oxidation catalyst solution with a mass concentration of 5%-10% is added, and the oxidation catalyst is a metal oxide or salt containing manganese, copper, and cobalt to promote the directional oxidation of ferrous hydroxide to generate ferric oxide and inhibit the generation of ferric oxide; during the oxidation process, the characteristic peak of ferric oxide at 1050cm is monitored in real time by infrared spectroscopy. -1 When the peak intensity reaches the characteristic peak of iron hydroxide at 560 cm -1 Stop ventilation when the intensity is 2-3 times higher than the pressure at the pump. S6, post-processing stage: Use a filter with water washing and pressing function to separate the solid and liquid. The solids are repeatedly washed with deionized water until the total soluble salt mass concentration is less than 0.5%, and then pressed to a moisture content of 35%-45%; the mud is rolled into columnar particles with a diameter of 3-5mm or particles of 20-40 mesh, and oxidized and dried in a hot air atmosphere of 40-110℃. The specific surface area of ​​the material after drying is controlled to be not less than 250m 2 / g, average pore diameter of 8-15nm, pore volume of 0.4-0.6cm 3 / g; When producing amorphous products, the mud is directly spread out for oxidation and drying, then crushed to a particle size of 0.85-1.18mm, and the finished product is obtained after screening.

2. The synthesis process of a multi-component iron-based new desulfurization material according to claim 1 is characterized in that: The bifunctional additive in step S1 is composed of lignin sulfonate and polyethylene glycol-400 in a mass ratio of 1:1, and the added amount is 0.1%-0.5% of the total iron element mass, which is used to simultaneously improve the particle dispersibility and molding interface bonding strength.

3. The synthesis process of a multi-component iron-based new desulfurization material according to claim 1 is characterized in that: The ferric salt solution and the alkaline solution in step S2 are injected through a microchannel reactor, the channel diameter of the microchannel reactor is 0.5-1 mm, the flow rate is 0.1-0.3 m / s, the pH value of the reaction system is dynamically fluctuated within the range of 3.5-4.5 with an amplitude of ±0.2, the fluctuation frequency is 0.5 Hz, and the generated ferric hydroxide flocculant has a pore size of 10-30 nm and a specific surface area of ​​80-120 m 2 / g.

4. The synthesis process of a multi-component iron-based new desulfurization material according to claim 1 is characterized in that: The dripping rate of the ferrous salt solution in step S3 is controlled in sections, with a dripping rate of 10 mL / min in the first 30 min and a dripping rate of 5 mL / min in the last 30 min. The D50 of the generated ferrous hydroxide solid is 2-5 μm, and its surface is covered with a thin oxide layer with a thickness of no more than 5 nm.

5. The synthesis process of a multi-component iron-based new desulfurization material according to claim 1 is characterized in that: The composite additive in step S4 adopts a "sequential co-precipitation" process: first, a titanium salt solution is added dropwise to generate a titanium hydroxide "core layer" with a particle size of no more than 1 μm, and then a copper / manganese mixed salt solution is added dropwise to generate a "shell layer" to form a core-shell structure, wherein the titanium salt accounts for 10%-30% of the total mass of the additive, the copper / manganese mixed salt accounts for 70%-90%, and the molar ratio of copper to manganese is 1:

2.

6. The synthesis process of a multi-component iron-based new desulfurization material according to claim 1 is characterized in that: In step S3, nitrogen is introduced to form an inert atmosphere, the nitrogen flow rate is 0.2-0.5 L / (min·L) of reaction liquid, and the reaction temperature is controlled at 30-40° C. to inhibit excessive oxidation of ferrous hydroxide.

7. The synthesis process of a multi-component iron-based new desulfurization material according to claim 1 is characterized in that: The oxidation catalyst solution in step S5 is a manganese dioxide suspension with a mass concentration of 5%-10%, and the added amount is 0.1%-0.5% of the total mass of the reaction system, so that the oxidation conversion rate of ferrous hydroxide is controlled at 50%-70%, forming a composite structure of ferric oxyhydroxide and ferrous hydroxide.

8. The synthesis process of a multi-component iron-based new desulfurization material according to claim 1, characterized in that: The specific surface area of ​​the material after drying in step S6 is not less than 250m 2 / g, average pore diameter of 8-15nm, pore volume of 0.4-0.6cm 3 / g, which is achieved by the synergistic effect of the porous flocculant in step S2 and the core-shell additive in step 4.

9. The synthesis process of a multi-component iron-based new desulfurization material according to claim 1, characterized in that: The ferric iron salt solution is a polyferric sulfate solution, the alkaline solution is a sodium hydroxide solution, and the ferrous salt solution is a ferrous sulfate solution.

10. The synthesis process of a multi-component iron-based new desulfurization material according to claim 1, characterized in that: In step S1, 5-10 kHz ultrasonic dispersion is used for 10-15 min with an ultrasonic power of 50-100 W to destroy the initial agglomerates of the ferrous hydroxide particles.