Preparation method of iron oxide desulfurizer

Abstract

The present invention relates to a preparation method of an iron oxide desulfurizer, which belongs to the technical field of iron oxide desulfurizers. The method comprises the following steps: S1. taking a synthesis reactor, adding FeCl2·4H2O solution to the reactor under nitrogen protection, subsequently adding a sodium carbonate aqueous solution thereto for reaction, controlling the alkali ratio to be a sodium carbonate solid to FeCl2·4H2O solid molar ratio of (1-1.2): 1, stirring while adding, then blowing ozone-containing air into the reactor, aging for 2-2.5 hours at 30-35°C, filtering, washing the filter cake with water, and drying to obtain iron oxide oxyhydroxide; S2. placing the iron oxide oxyhydroxide obtained in step S1 into a mixing mill with multi-walled carbon nanotubes, sodium dodecylbenzenesulfonate, and guar gum for mixing and grinding for 10-15 minutes, then adding adipic acid and water thereto, continuing to mix and grind for 10-15 minutes, extruding into strips, and drying to obtain an iron oxide desulfurizer product. The product of the present invention improves the strength of the iron oxide desulfurizer while ensuring its desulfurization performance.

Description

Technical Field

[0001] The invention belongs to the technical field of iron oxide desulfurizers and relates to a preparation method of the iron oxide desulfurizer. Background Art

[0002] Hydrogen sulfide is a colorless, corrosive, highly toxic acidic gas with the smell of rotten eggs. It is widely present in industrial processes such as the petroleum industry, coal chemical industry, natural gas extraction and sewage treatment. It has adverse effects on human health, the environment and equipment. Therefore, the removal of hydrogen sulfide gas is particularly important.

[0003] Single metal oxide desulfurizers generally suffer from low sulfur capacity and mechanical strength. Existing high-sulfur capacity desulfurizers are primarily iron oxyhydroxide desulfurizers, which are widely used to remove sulfur-containing tail gas from natural gas, associated oilfield gas, coalbed methane, and biogas. However, iron oxyhydroxide desulfurizers still suffer from low strength.

[0004] The application number 202310514348.1, "A high-strength iron oxyhydroxide desulfurizer and its preparation method", uses Fe-β molecular sieve as the core layer and iron oxyhydroxide as the shell layer. The Fe-β molecular sieve is wrapped with iron oxyhydroxide on the outside. Although this core-shell structure of iron oxyhydroxide desulfurizer improves the strength of the iron oxyhydroxide desulfurizer, its crystallization is complex.

[0005] The "Iron oxide desulfurizer and its preparation method" with application number 201410316813.1 uses a secondary step-by-step oxidation method to first react a solid soluble ferrous salt with a carbonate to obtain a reaction mixture, then react the reaction mixture with a hydroxide, and then obtain an iron oxide desulfurizer through physical vacuum extrusion molding and drying. The strength can reach 65N / cm.

[0006] It can be seen that the strength of iron oxide desulfurizer is a key issue in research in this industry. Summary of the Invention

[0007] The purpose of the present invention is to improve the strength of the iron oxide desulfurizer while ensuring its desulfurization performance.

[0008] The present invention adopts the following technical solutions to achieve its purpose:

[0009] A method for preparing an iron oxide desulfurizer comprises the following steps:

[0010] S1. Take a synthesis reactor, under nitrogen protection, add FeCl2·4H2O solution to the reactor, then add sodium carbonate aqueous solution to react, control the alkali ratio of sodium carbonate solid to FeCl2·4H2O solid molar ratio (1-1.2): 1, add while stirring, then blown into the reactor containing ozone air, mature at 30-35 ° C for 2 to 2.5h, filter, wash the filter cake with water, and dry to obtain iron oxyhydroxide (95-97wt% amorphous);

[0011] S2. The iron oxyhydroxide obtained in step S1 is placed in a mixer with multi-walled carbon nanotubes, sodium dodecylbenzene sulfonate, and guar gum and mixed for 10-15 minutes. Adipic acid and water are then added and the mixture is mixed for another 10-15 minutes. The mixture is extruded into strips and dried to obtain an iron oxide desulfurizer product.

[0012] Preferably, the stirring rate is 200-300 r / min and the reaction time is 50-70 min.

[0013] Preferably, the ozone in the ozone-containing air accounts for 0.3-0.5% of the air volume, and the ventilation volume is 1.5-1.8 L / min.

[0014] Preferably, the concentration of the FeCl2·4H2O solution is 1-1.5 mol / L, and the concentration of the sodium carbonate aqueous solution is 1-1.8 mol / L.

[0015] Preferably, in step S1, the filter cake is dried at 50-70°C after being water-soluble.

[0016] Preferably, the amount of multi-walled carbon nanotubes added is 10-15% of the mass of the iron oxyhydroxide, the amount of sodium dodecylbenzenesulfonate added is 1-2% of the mass of the iron oxyhydroxide, the amount of guar gum added is 0.5-1% of the mass of the iron oxyhydroxide, and the amount of adipic acid added is 1-3% of the mass of the iron oxyhydroxide.

[0017] Preferably, the drying temperature in step S2 is 80-110° C., and the drying time is 5-8 hours.

[0018] The beneficial effects of the present invention are:

[0019] The iron oxyhydroxide synthesized in step 1 of the present invention is amorphous iron oxyhydroxide. The raw materials used are simple and readily available, and the synthesis conditions are mild. The resulting amorphous iron oxyhydroxide has excellent desulfurization performance. By adding ozone and controlling the ventilation volume, the oxidation rate is increased, thereby further improving the formation of amorphous iron oxyhydroxide. In step 2, multi-walled carbon nanotubes are added, serving as both an additive and a carrier, which not only improves the mechanical strength of the iron oxyhydroxide but also leverages its high specific surface area and good dielectric properties to further enhance the desulfurization performance of the desulfurizer.

[0020] Sodium dodecylbenzenesulfonate is added as a surfactant to improve the dispersion performance of the raw materials. Guar gum is used as a binder. Adipic acid is added as an additive and mixed with water to form a gum solution, which is formed on the surface of the inorganic material in the form of an emulsion, solving the problem of low adhesion between inorganic materials. The addition of adipic acid to the emulsion formed on the surface of the inorganic material reduces its pulverization problem. DETAILED DESCRIPTION

[0021] Example 1

[0022] Preparation of iron oxyhydroxide:

[0023] Take a synthesis reactor and, under nitrogen protection, add a 1 mol / L FeCl2·4H2O solution to the reactor, then add a 1.2 mol / L sodium carbonate aqueous solution to react while stirring at a stirring rate of 250 r / min and a reaction time of 60 min. Then, ozone-containing air (ozone accounts for 0.4% of the air volume) is blown into the reactor at a ventilation rate of 1.7 L / min, matured at 35°C for 2h, filtered, and the filter cake is washed with water and dried at 60°C to obtain iron oxyhydroxide (about 95wt% amorphous).

[0024] Preparation of iron oxide desulfurizer products:

[0025] 1 kg of ferric oxyhydroxide, 0.15 kg of multi-walled carbon nanotubes, 0.02 kg of sodium dodecylbenzenesulfonate, and 0.01 kg of guar gum were put into a mixer and milled for 15 minutes. Then, 0.02 kg of adipic acid and 0.5 kg of water were added thereto, and the mixing was continued for 15 minutes. The mixture was extruded into strips and dried at 80°C for 8 hours to obtain an iron oxide desulfurizer product.

[0026] The obtained iron oxide desulfurizer was subjected to a sulfur capacity test according to the method in HG / T 5759-2020 Room-temperature iron oxide desulfurizer, and the sulfur capacity was 42% and the compressive strength was 76 N / cm. It was immersed in carbon tetrachloride, taken out, filtered and dried, and no powdering occurred.

[0027] Example 2

[0028] Preparation of iron oxyhydroxide:

[0029] Take a synthesis reactor and, under nitrogen protection, add a 1 mol / L FeCl2·4H2O solution to the reactor, then add a 1.1 mol / L sodium carbonate aqueous solution to react while stirring at a stirring rate of 300 r / min and a reaction time of 50 min. Then, ozone-containing air (ozone accounts for 0.5% of the air volume) is blown into the reactor at a ventilation rate of 1.5 L / min. The reaction is aged at 30° C. for 2.5 h, filtered, and the filter cake is washed with water and dried at 70° C. to obtain iron oxyhydroxide (about 96 wt% amorphous).

[0030] Preparation of iron oxide desulfurizer products:

[0031] 1 kg of ferric hydroxide, 0.1 kg of multi-walled carbon nanotubes, 0.01 kg of sodium dodecylbenzenesulfonate, and 0.01 kg of guar gum were put into a mixer and milled for 10 minutes. Then, 0.03 kg of adipic acid and 0.4 kg of water were added thereto, and the mixture was further milled for 10 minutes. The mixture was extruded into strips and dried at 110°C for 5 hours to obtain an iron oxide desulfurizer product.

[0032] The obtained iron oxide desulfurizer was subjected to a sulfur capacity test according to the method in HG / T 5759-2020 Room-temperature iron oxide desulfurizer, and the sulfur capacity was 41% and the compressive strength was 74 N / cm. It was immersed in carbon tetrachloride, taken out, filtered and dried, and no powdering occurred.

[0033] Example 3

[0034] Preparation of iron oxyhydroxide:

[0035] Take a synthesis reactor and, under nitrogen protection, add a 1.5 mol / L FeCl2·4H2O solution to the reactor, then add a 1.6 mol / L sodium carbonate aqueous solution to react while stirring at a stirring rate of 200 r / min and a reaction time of 70 min. Then, ozone-containing air (ozone accounts for 0.3% of the air volume) is blown into the reactor at a ventilation rate of 1.8 L / min, matured at 30°C for 2.5 h, filtered, and the filter cake was washed with water and dried at 70°C to obtain iron oxyhydroxide (about 95 wt% amorphous).

[0036] Preparation of iron oxide desulfurizer products:

[0037] 1 kg of ferric hydroxide, 0.13 kg of multi-walled carbon nanotubes, 0.01 kg of sodium dodecylbenzenesulfonate, and 0.008 kg of guar gum were put into a mixer and milled for 10 minutes. Then, 0.015 kg of adipic acid and 0.5 kg of water were added thereto, and the mixing was continued for 10 minutes. The mixture was extruded into strips and dried at 100°C for 6 hours to obtain an iron oxide desulfurizer product.

[0038] The obtained iron oxide desulfurizer was subjected to a sulfur capacity test according to the method in HG / T 5759-2020 Room-temperature iron oxide desulfurizer, and the sulfur capacity was 43% and the compressive strength was 73N / cm. It was immersed in carbon tetrachloride, taken out, filtered and dried, and no powdering occurred.

[0039] Example 4

[0040] Preparation of iron oxyhydroxide:

[0041] Take a synthesis reactor and, under nitrogen protection, add a 1 mol / L FeCl2·4H2O solution to the reactor, then add a 1.2 mol / L sodium carbonate aqueous solution to react while stirring at a stirring rate of 250 r / min and a reaction time of 60 min. Then, ozone-containing air (ozone accounts for 0.4% of the air volume) is blown into the reactor at a ventilation rate of 1.7 L / min, matured at 35°C for 2h, filtered, and the filter cake is washed with water and dried at 60°C to obtain iron oxyhydroxide (about 95wt% amorphous).

[0042] The obtained iron oxyhydroxide desulfurizer was subjected to a sulfur capacity test according to the method in HG / T 5759-2020 Room-temperature iron oxide desulfurizer, and the sulfur capacity was 34% and the compressive strength was 48 N / cm. It was immersed in carbon tetrachloride, taken out, filtered, dried, and partially powdered.

[0043] Example 5

[0044] Preparation of iron oxyhydroxide:

[0045] Take a synthesis reactor and, under nitrogen protection, add a 1 mol / L FeCl2·4H2O solution to the reactor, then add a 1.2 mol / L sodium carbonate aqueous solution to react while stirring at a stirring rate of 250 r / min and a reaction time of 60 min. Then, ozone-containing air (ozone accounts for 0.4% of the air volume) is blown into the reactor at a ventilation rate of 1.7 L / min, matured at 35°C for 2h, filtered, and the filter cake is washed with water and dried at 60°C to obtain iron oxyhydroxide (about 95wt% amorphous).

[0046] Preparation of iron oxide desulfurizer products:

[0047] 1 kg of ferric hydroxide, 0.15 kg of diatomaceous earth, 0.02 kg of sodium dodecylbenzenesulfonate and 0.01 kg of guar gum were put into a mixer and milled for 15 minutes. Then, 0.02 kg of adipic acid and 0.5 kg of water were added and the mixing was continued for 15 minutes. The mixture was extruded into strips and dried at 80°C for 8 hours to obtain an iron oxide desulfurizer product.

[0048] The obtained iron oxide desulfurizer was subjected to a sulfur capacity test according to the method in HG / T 5759-2020 Room-temperature iron oxide desulfurizer. The sulfur capacity was 36% and the compressive strength was 58 N / cm. It was immersed in carbon tetrachloride, taken out, filtered and dried, and no powdering occurred.

[0049] Example 6

[0050] Preparation of iron oxyhydroxide:

[0051] Take a synthesis reactor and, under nitrogen protection, add a 1 mol / L FeCl2·4H2O solution to the reactor, then add a 1.2 mol / L sodium carbonate aqueous solution to react while stirring at a stirring rate of 250 r / min and a reaction time of 60 min. Then, ozone-containing air (ozone accounts for 0.4% of the air volume) is blown into the reactor at a ventilation rate of 1.7 L / min, matured at 35°C for 2h, filtered, and the filter cake is washed with water and dried at 60°C to obtain iron oxyhydroxide (about 95wt% amorphous).

[0052] Preparation of iron oxide desulfurizer products:

[0053] 1 kg of ferric oxyhydroxide, 0.15 kg of multi-walled carbon nanotubes, 0.02 kg of sodium dodecylbenzenesulfonate, and 0.01 kg of guar gum were put into a mixer and milled for 15 minutes, and then 0.5 kg of water was added and the mixture was further milled for 15 minutes. The mixture was extruded into strips and dried at 80°C for 8 hours to obtain an iron oxide desulfurizer product.

[0054] The obtained iron oxide desulfurizer was subjected to a sulfur capacity test according to the method in HG / T 5759-2020 Room-temperature iron oxide desulfurizer, and the sulfur capacity was 42% and the compressive strength was 65 N / cm. It was immersed in carbon tetrachloride, taken out, filtered, dried, and partially pulverized.

Claims

1. A method for preparing an iron oxide desulfurizer, characterized in that: The following steps are involved: S1. In a synthesis reactor, under nitrogen, add FeCl2·4H2O solution to the reactor, followed by sodium carbonate aqueous solution, with the alkali ratio controlled to be a molar ratio of sodium carbonate solid to FeCl2·4H2O solid of 1-1.2:1, with stirring. Ozone-containing air is then bubbled into the reactor, and the mixture is aged at 30-35°C for 2-2.5 hours. The mixture is filtered, the filter cake is washed with water, and then dried to obtain iron oxyhydroxide. S2. The iron oxyhydroxide obtained in step S1 is mixed with multi-walled carbon nanotubes, sodium dodecylbenzenesulfonate, and guar gum and placed in a mixing mill and mixed for 10-15 min. Adipic acid and water are then added thereto and the mixture is mixed for 10-15 min. Extrusion is performed and dried to obtain an iron oxide desulfurization agent product. The amount of multi-walled carbon nanotubes added is 10-15% of the mass of the ferric oxyhydroxide, the amount of sodium dodecylbenzenesulfonate added is 1-2% of the mass of the ferric oxyhydroxide, the amount of guar gum added is 0.5-1% of the mass of the ferric oxyhydroxide, and the amount of adipic acid added is 1-3% of the mass of the ferric oxyhydroxide.

2. The method for preparing an iron oxide desulfurizer according to claim 1, wherein: The stirring rate is 200-300 r / min and the reaction time is 50-70 min.

3. The method for preparing an iron oxide desulfurizer according to claim 1, wherein: Ozone in ozone-containing air accounts for 0.3-0.5% of the air volume, and the ventilation volume is 1.5-1.8L / min.

4. The method for preparing an iron oxide desulfurizer according to claim 1, wherein: The concentration of the FeCl2·4H2O solution is 1-1.5 mol / L, and the concentration of the sodium carbonate aqueous solution is 1-1.8 mol / L.

5. The method for preparing an iron oxide desulfurizer according to claim 1, characterized in that: In step S1, the filter cake is dried at 50-70°C after being water-soluble.

6. The method for preparing an iron oxide desulfurizer according to claim 1, characterized in that: The drying temperature in step S2 is 80-110° C., and the drying time is 5-8 hours.