Desulfurizing agent and desulfurizing method using the same

Abstract

The invention discloses a desulfurizer and a desulfurization method using the desulfurizer, and belongs to the technical field of desulfurizer processing. The invention is used to solve the technical problem that in the prior art, gas molecules of zinc oxide type desulfurizer are not easy to diffuse and adsorb on the surface of particles in gas desulfurization engineering, and the sulfur capacity, specific surface area and desulfurization efficiency of the desulfurizer need to be further improved. The desulfurizer in the invention is prepared by emulsifying and granulating after molten salt etching modified kaolin, loaded activated carbon and sol form a mixed colloid according to a weight ratio of 8-9:13-15:60. The mixed colloid is prepared by emulsification and granulation. The kaolin is modified by molten salt etching, activated carbon loaded with zinc and magnesium metal oxides and nitrides is prepared as a base material, and silica sol is used as an auxiliary agent. After emulsification and granulation, not only the sulfur capacity and specific surface area of ​​the desulfurizer are effectively improved, but also the desulfurization efficiency of desulfurization using the desulfurizer is improved.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurizing agent processing, and in particular to a desulfurizing agent and a desulfurization method using the desulfurizing agent. Background Art

[0002] Under the dual goals of environmental governance, clean and efficient utilization of coal resources is imminent. Coal gasification is an important way to achieve clean and efficient utilization of coal. However, the sulfur impurities contained in coal will inevitably generate gaseous sulfides during the gasification process, mainly inorganic sulfur hydrogen sulfide. Hydrogen sulfide will not only corrode pipeline equipment, but also poison downstream catalysts.

[0003] Prior art, a Chinese invention patent with publication number CN111849562A, discloses a desulfurization device and method for synthesis gas produced from coal gasification, and relates to the technical field of gas desulfurization. The desulfurization method for synthesis gas produced from coal gasification comprises: reacting synthesis gas produced from coal gasification with a desulfurizer to remove sulfides in the synthesis gas to obtain desulfurized synthesis gas and a deactivated desulfurizer, wherein the desulfurizer is a desulfurizer modified by phosphorus or boron. The above device and method can ensure sufficient desulfurization, and the desulfurizer can be recycled and regenerated during the desulfurization process, and the desulfurization accuracy and sulfur capacity can remain basically unchanged.

[0004] Zinc oxide is a conversion and absorption desulfurizer with a strong affinity for sulfur. The product, zinc sulfide, is highly stable and can remove hydrogen sulfide and some organic sulfides from the gas. However, zinc oxide has a small specific surface area. When zinc oxide is used for desulfurization, the contact area between zinc oxide and hydrogen sulfide is small, and gas molecules are not easy to diffuse and adsorb on the surface of the particles, making it difficult to effectively adsorb hydrogen sulfide in the gas. In addition, the sulfidation reaction of zinc oxide and hydrogen sulfide is a gradual process. A zinc sulfide layer will first form on the surface of zinc oxide particles, and gradually thicken and cover the surface of zinc oxide particles as the reaction proceeds, hindering hydrogen sulfide molecules from further diffusing into the interior of zinc oxide particles for reaction. The desulfurization efficiency and sulfur capacity of the desulfurizer need to be further improved.

[0005] In view of the technical defects in this aspect, a solution is now proposed. Summary of the invention

[0006] The object of the present invention is to provide a desulfurizer and a desulfurization method using the desulfurizer, which is used to solve the technical problems that in the prior art zinc oxide type desulfurizer in gas desulfurization projects, gas molecules are not easy to diffuse and adsorb on the particle surface, and the sulfur capacity, specific surface area and desulfurization efficiency of the desulfurizer need to be further improved.

[0007] The purpose of the present invention can be achieved by the following technical scheme: a desulfurizer, which is prepared by emulsifying and granulating a mixed glue solution composed of molten salt etched modified kaolin, loaded activated carbon, and sol in a weight ratio of 8-9:13-15:60;

[0008] The emulsification granulation method is as follows: adding the emulsion into the reactor and stirring, setting the stirring speed to 580-620 r / min, dripping the mixed glue into the reactor, aging for 3-5 hours, and post-processing to obtain the desulfurizer.

[0009] The synthesis reaction mechanism of the desulfurizer is:

[0010] The molten salt etched modified kaolin, loaded activated carbon and sol are pre-mixed to form a stable mixed colloid. Under the action of high-speed stirring, sufficient physical mixing occurs between the emulsion and the mixed colloid, so that the kaolin, activated carbon and sol components in the mixed colloid can be evenly dispersed in the emulsion, forming stable emulsified coated particles in the emulsion. After aging, the components in the mixed system have more sufficient time to interact and rearrange, forming a more stable structure and performance. After post-processing operations, the solvent and unreacted impurities in the mixed system are removed, leaving a desulfurizer with a high specific surface area.

[0011] Furthermore, the emulsion is composed of sodium dodecyl sulfate, Tween-80, Span 20, purified water and anhydrous ethanol in a dosage ratio of 4g:2g:1g:60mL:40mL, the volume ratio of the emulsion and the mixed glue is 5:1, and the post-treatment includes: after aging, filtration, washing the filter cake with purified water until it is neutral and then drying it, transferring the filter cake to a drying oven at a temperature of 80-90°C, and vacuum drying it to constant weight to obtain a desulfurizer.

[0012] Further, the molten salt etched modified kaolin is processed by the following steps:

[0013] A1. Add potassium carbonate, potassium nitrate and kaolin into a ball mill, and pass through a 100-mesh sieve after ball milling to obtain a mixed powder;

[0014] A2. Place the mixed powder in a muffle furnace, raise the temperature of the muffle furnace to 360-380°C, keep the temperature and roast for 3-4 hours, and post-treat to obtain roasted modified kaolin;

[0015] A3. Add calcined modified kaolin, purified water, sodium hexametaphosphate and nitric acid into a reactor and stir. The temperature of the reactor is raised to 60-70° C. and stirred for 40-60 minutes. The molten salt etched modified kaolin is obtained by post-treatment.

[0016] The synthetic reaction mechanism of molten salt etching modified kaolin is:

[0017] After potassium nitrate, potassium carbonate and kaolin are mixed by ball milling, potassium carbonate and potassium nitrate partially melt under high temperature to form a molten salt mixed system. The molten salt can penetrate into the pores and interlayer structure of kaolin. Kaolin undergoes dehydration, dehydroxylation and other reactions at high temperature, resulting in changes in its crystal structure. Sodium hexametaphosphate is ionized in water to produce phosphate ions. These ions may form complexes with metal ions (such as aluminum and silicon) in kaolin, thereby further promoting the dissolution and etching of kaolin, destroying the crystal structure of kaolin and increasing its specific surface area and porosity.

[0018] Furthermore, in step A1, the weight ratio of potassium carbonate, potassium nitrate and kaolin is 7:13:2; in step A3, the amount ratio of the roasted modified kaolin, purified water, sodium hexametaphosphate and nitric acid is 10g:100mL:3g:4mL, and the concentration of the nitric acid is 6-8mol / L. The post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, filtered, the filter cake is washed with purified water until it is neutral and then dried, the filter cake is transferred to a drying oven at a temperature of 70-80°C, dried to constant weight, crushed, and passed through a 100-mesh sieve to obtain molten salt etched modified kaolin.

[0019] Further, the loaded activated carbon is processed by the following steps:

[0020] B1. Add zinc nitrate, magnesium nitrate, urea and methanol into a reactor, stir at room temperature until the system is dissolved, add acidified activated carbon into the reactor, ultrasonically disperse for 40-60 minutes, and post-treat to obtain a loaded activated carbon precursor;

[0021] B2. Place the loaded activated carbon in a muffle furnace, raise the temperature of the muffle furnace to 210-260°C, and keep it warm for 180-220 minutes. Raise the temperature of the muffle furnace to 350-400°C, and keep it warm for 200-260 minutes. Cool down the material, crush it, and pass it through a 100-mesh sieve to obtain the loaded activated carbon.

[0022] The synthetic reaction mechanism of loaded activated carbon is:

[0023] Using methanol as solvent, zinc nitrate, magnesium nitrate and urea are uniformly mixed. Under ultrasonic environment, zinc nitrate, magnesium nitrate, urea and acidified activated carbon are uniformly dispersed, and the functional groups on the surface of the acidified activated carbon and the metal ions in the solution are loaded onto the activated carbon through intermolecular forces. Under high temperature, urea is initially decomposed to produce some intermediate products that interact with the functional groups on the surface of the activated carbon to form preliminary adsorption or chemical bonding. As the temperature rises and enters the high temperature stage, urea will further decompose to produce ammonia, carbon dioxide and Gaseous products such as water vapor, ammonia has a high reaction activity at high temperature, ammonia reacts with carbon atoms or other functional groups on the surface of activated carbon to form amino, amide, nitroso or nitro groups, and at high temperature, urea decomposes to produce ammonia and other gaseous products that escape from the pores of the activated carbon, which helps to further dredge and expand the pore structure. At the same time, metal nitrates decompose or metals are oxidized to form metal oxides, metal carbides or metal-carbon complexes on the carbon atoms on the surface of the activated carbon, and the metal is loaded on the activated carbon to prepare loaded activated carbon.

[0024] Furthermore, in step B1, the amount ratio of zinc nitrate, magnesium nitrate, urea, methanol and acidified activated carbon is 3g:1g:4g:50mL:12g, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is increased to 50-60°C, and the solvent is evaporated under reduced pressure to obtain a loaded activated carbon precursor.

[0025] Furthermore, the preparation method of the acidified activated carbon is as follows: the activated carbon and the acidified modified liquid are added into a reactor and stirred, the temperature of the reactor is increased to 60-70° C., the reactor is kept warm and stirred for 4-6 hours, and the acidified activated carbon is obtained by post-treatment.

[0026] The synthetic reaction mechanism of acidified activated carbon is:

[0027] Both hydrogen peroxide and nitric acid are highly oxidizing. Hydrogen peroxide is more oxidizing under acidic conditions. Nitric acid provides a highly oxidizing acidic environment for the acidifying modification liquid. The surface of activated carbon is rich in various functional groups such as hydroxyl groups and lactone groups. Under the action of the acidifying modification liquid, an oxidation reaction occurs, resulting in changes in the functional groups on the surface of the activated carbon. New functional groups such as carboxyl groups and ketone groups may be introduced, while some unstable or inert functional groups are removed, increasing the chemical activity of the surface of the activated carbon. In the environment of the acidifying modification liquid, the pore walls on the activated carbon are eroded, unblocking and expanding the original pores, making the pore structure more open and connected, and increasing the specific surface area and porosity of the activated carbon.

[0028] Furthermore, the dosage ratio of the activated carbon and the acidified modification liquid is 2g:7mL, the acidified modification liquid is composed of 5-7mol / L nitric acid and 10-12wt% hydrogen peroxide in a volume ratio of 5:1, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, filtered, the filter cake is washed with purified water until it is neutral and then dried, the filter cake is transferred to a drying oven at a temperature of 70-80°C, and dried to constant weight to obtain acidified activated carbon.

[0029] Furthermore, the preparation method of the sol is: add tetraethyl orthosilicate, anhydrous ethanol and nitric acid solution into a reactor and stir, and stir at room temperature for 20-30 minutes to obtain silica sol, wherein the dosage ratio of tetraethyl orthosilicate, anhydrous ethanol and nitric acid solution is 1g:5mL:1mL, and the concentration of the nitric acid solution is 0.8-1.2mol / L.

[0030] The synthesis reaction mechanism of sol is:

[0031] TEOS is hydrolyzed into silanol (Si-OH) and ethanol in an acidic ethanol-water mixture. The silanol molecules generated by the hydrolysis undergo a polycondensation reaction, removing water molecules to form silicon-oxygen bonds (Si-O-Si), thereby generating a three-dimensional network structure of silica sol and forming silica sol.

[0032] The present invention also provides a desulfurization method using a desulfurizing agent, comprising the following steps:

[0033] S1. Fill the prepared desulfurizer layer by layer into two desulfurization tanks to form a plurality of superimposed desulfurization beds in the desulfurization tanks. The thickness of the desulfurization beds is 10 cm, and the distance between two adjacent desulfurization beds is 8 cm.

[0034] S2. A main air inlet pipe is provided on the top of the two desulfurization tanks, one end of which is connected to the top of the two desulfurization tanks through two air inlet branches, solenoid valves are installed on the two air inlet branches, and a main air outlet pipe is provided at the bottom of the two desulfurization tanks, one end of which is connected to the bottom of the two desulfurization tanks through two air outlet branches, and an air outlet check valve and a point-type hydrogen sulfide detector are installed on the two air outlet branches;

[0035] S3, when working, a solenoid valve on one of the air inlet branches is opened, and the mixed gas containing hydrogen sulfide is transported from the air inlet pipe at the top of the desulfurization tank to the desulfurization tank, and then discharged from the air outlet pipe at the bottom of the desulfurization tank after being adsorbed and desulfurized by multiple shedding beds;

[0036] S4. The point-type hydrogen sulfide detector installed on the outlet branch pipe monitors the hydrogen sulfide content of the gas in the outlet branch pipe in real time and feeds back the signal to the external PLC controller. When the point-type hydrogen sulfide detector detects that the sulfur content in the gas discharged from the outlet pipe is higher than 0.2ppm, the PLC controller gives signals to the two one-way valves according to the feedback signal of the point-type hydrogen sulfide detector, closes the one-way valve that is in the open state at this time, and opens the other one-way valve that is in the closed state, and sends out a continuous alarm to remind the replacement of the desulfurizer in the desulfurization tank.

[0037] The present invention has the following beneficial effects:

[0038] 1. The desulfurizer of the present invention is prepared by emulsifying and granulating porous desulfurizer by using molten salt etching modified kaolin and activated carbon loaded with zinc, magnesium metal oxides and nitrides as base materials, and using silica sol as an auxiliary agent. The activated carbon is acidified and then loaded to increase the specific surface area and activity of the activated carbon, thereby increasing the adsorption activity of the desulfurizer for hydrogen sulfide. The kaolin is modified by molten salt etching to increase its specific surface area and porosity, and is combined with porous activated carbon to increase the specific surface area of ​​the desulfurizer, so that the adsorption capacity of the desulfurizer for hydrogen sulfide is increased, and the desulfurization efficiency of hydrogen sulfide in the gas is improved. In the process of desulfurizing the gas, a hydrogen sulfide content detector is selected to detect the hydrogen sulfide content in the gas in real time, and the detection signal is combined with a PLC controller. After the sulfur content of the gas in the outlet pipe is increased, the air inlet pipeline can be automatically switched, thereby controlling the sulfur content in the outlet pipe while continuously performing the desulfurization operation.

[0039] 2. The desulfurizer of the present invention increases the loading amount of zinc nitrate, magnesium nitrate and urea on activated carbon by acidification modification of activated carbon, and then reacts with the acidified activated carbon after the zinc nitrate, magnesium nitrate and urea are decomposed under high temperature to form nitride and metal oxide loading on the acidified activated carbon; the nitrogen-containing compounds loaded on the acidified activated carbon include amino groups, amide groups, etc., the nitrogen atoms in these nitrogen-containing compounds carry lone pairs of electrons, the hydrogen atoms in hydrogen sulfide carry partial positive charges, and the lone pairs of electrons on the nitrogen atoms carry partial negative charges, and this charge distribution enables them to form strong hydrogen bonds, and the formation of hydrogen bonds increases the interaction between the surface of activated carbon and hydrogen sulfide molecules, thereby improving the adsorption capacity of activated carbon for hydrogen sulfide, and activated carbon itself has a certain adsorption capacity, However, its surface active sites are limited. When metal compounds containing zinc and magnesium are loaded on activated carbon, the loaded zinc and magnesium metal compounds can react chemically with hydrogen sulfide molecules and form more stable chemical bonds, thereby firmly adsorbing the hydrogen sulfide molecules on the surface of the activated carbon, forming a synergistic sulfur-binding desulfurization system of physical adsorption and chemical fixation in the desulfurizer, thereby improving the sulfur capacity and desulfurization effect of the desulfurizer. Zinc and magnesium metal compounds act as catalysts in the desulfurization process, with the initial adsorption and reaction of zinc and hydrogen sulfide molecules, and magnesium accelerates the reaction process by stabilizing reaction intermediates or promoting the conversion of products, providing additional reaction paths for hydrogen sulfide adsorption or reducing the energy barriers in the reaction path, reducing the activation energy of the reaction, and allowing the desulfurization reaction to proceed at a faster rate at a lower temperature.

[0040] 3. During the preparation process of the desulfurizer of the present invention, silica sol of tetraethyl orthosilicate is introduced to increase the silicon content in the desulfurizer. During the emulsification granulation process, the interaction between the emulsion and the mixed colloid helps to form a uniform particle structure. Moreover, the particles formed during the emulsification granulation process usually have good sphericity and narrow particle size distribution, which helps to increase the specific surface area of ​​the desulfurizer. In addition, the addition of the emulsifier may also improve the wettability of the particle surface, making it easier for gas molecules to diffuse and adsorb on the particle surface, thereby further increasing the specific surface area. The uniform particle structure formed by emulsification granulation is conducive to the uniform distribution and rapid diffusion of gas molecules inside the desulfurizer, reducing mass transfer resistance. At the same time, the larger specific surface area and rich pore structure also provide more active sites, so that the desulfurization reaction can be carried out more quickly and thoroughly, thereby improving the desulfurization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 A schematic diagram of the device and pipeline of the desulfurization method using a desulfurizer according to the present invention.

[0043] In the figure: 1. Desulfurization tank; 2. Solenoid valve; 3. Check valve; 4. Point-type hydrogen sulfide detector. DETAILED DESCRIPTION

[0044] The technical scheme of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] This embodiment provides a method for preparing a desulfurizing agent, comprising the following steps:

[0047] S1. Preparation of molten salt etched modified kaolin

[0048] Weigh: 700 g potassium carbonate, 1300 g potassium nitrate, and 200 g kaolin, add them into a ball mill, and pass through a 100-mesh sieve after ball milling to obtain a mixed powder;

[0049] The mixed powder was placed in a muffle furnace, the temperature of the muffle furnace was raised to 360°C, and the mixture was calcined for 3 hours, and then post-treated to obtain calcined modified kaolin;

[0050] Weigh: 500 g of calcined modified kaolin, 5000 mL of purified water, 150 g of sodium hexametaphosphate and 200 mL of 6 mol / L nitric acid, add into the reactor and stir, raise the temperature of the reactor to 60°C, keep warm and stir for 40 minutes, lower the temperature of the reactor to room temperature, filter, wash the filter cake with purified water until it is neutral and then dry, transfer the filter cake to a drying oven at a temperature of 70°C, dry to constant weight, crush, and pass through a 100-mesh sieve to obtain molten salt etched modified kaolin.

[0051] S2. Preparation of acidified activated carbon

[0052] 5 mol / L nitric acid and 10 wt % hydrogen peroxide were mixed uniformly in a volume ratio of 5:1 to obtain an acidified modified solution;

[0053] Weigh: 300 g of activated carbon and 1050 mL of acidified modified liquid are added to the reactor and stirred. The temperature of the reactor is raised to 60°C, and the mixture is kept warm and stirred for 4 hours. The temperature of the reactor is lowered to room temperature, and the filter cake is washed with purified water until it is neutral and then dried. The filter cake is transferred to a drying oven at 70°C and dried to constant weight to obtain acidified activated carbon.

[0054] S3. Preparation of loaded activated carbon

[0055] Weigh: 60g zinc nitrate, 20g magnesium nitrate, 80g urea, and 1000mL methanol, add them into a reactor, stir at room temperature until the system is dissolved, add 240g acidified activated carbon into the reactor, ultrasonically disperse for 40min, raise the temperature of the reactor to 50°C, and evaporate the solvent under reduced pressure to obtain a loaded activated carbon precursor;

[0056] The loaded activated carbon was placed in a muffle furnace, the temperature of the muffle furnace was increased to 210°C, and the temperature was kept warm for 180 minutes. The temperature of the muffle furnace was increased to 350°C, and the temperature was kept warm for 200 minutes. The material was cooled, discharged, crushed, and passed through a 100-mesh sieve to obtain the loaded activated carbon.

[0057] S4. Preparation of sol

[0058] Weigh: 200 g of tetraethyl orthosilicate, 1000 mL of anhydrous ethanol and 200 mL of 0.8 mol / L nitric acid solution, add into a reaction kettle and stir at room temperature for 20 min to obtain silica sol.

[0059] S5. Preparation of desulfurizing agent

[0060] The molten salt etched modified kaolin, loaded activated carbon and sol were added into the reactor in a weight ratio of 8:13:60, and stirred at room temperature for 2 hours to obtain a mixed glue solution;

[0061] Sodium lauryl sulfate, Tween-80, Span 20, purified water and anhydrous ethanol were mixed uniformly in a ratio of 4g:2g:1g:60mL:40mL to obtain an emulsion;

[0062] The emulsion was added into the reactor and stirred. The stirring speed was set to 580 r / min. The mixed rubber solution was added dropwise into the reactor. After the addition was completed, it was aged for 3 h and filtered. The filter cake was washed with purified water until it was neutral and then dried. The filter cake was transferred to a drying oven at 80°C and vacuum dried to constant weight to obtain a desulfurizer, wherein the volume ratio of the emulsion and the mixed rubber solution was 5:1.

[0063] Example 2

[0064] This embodiment provides a method for preparing a desulfurizing agent, comprising the following steps:

[0065] S1. Preparation of molten salt etched modified kaolin

[0066] Weigh: 700 g potassium carbonate, 1300 g potassium nitrate, and 200 g kaolin, add them into a ball mill, and pass through a 100-mesh sieve after ball milling to obtain a mixed powder;

[0067] The mixed powder was placed in a muffle furnace, the temperature of the muffle furnace was raised to 370°C, and the mixture was calcined for 3.5 hours, and then post-treated to obtain calcined modified kaolin.

[0068] Weigh: 500 g of calcined modified kaolin, 5000 mL of purified water, 150 g of sodium hexametaphosphate and 200 mL of 7 mol / L nitric acid, add into the reactor and stir, raise the temperature of the reactor to 65°C, keep stirring for 50 minutes, lower the temperature of the reactor to room temperature, filter, wash the filter cake with purified water until neutral and then dry, transfer the filter cake to a drying oven at 75°C, dry to constant weight, crush, and pass through a 100-mesh sieve to obtain molten salt etched modified kaolin.

[0069] S2. Preparation of acidified activated carbon

[0070] 6 mol / L nitric acid and 11 wt % hydrogen peroxide were mixed uniformly in a volume ratio of 5:1 to obtain an acidified modified solution;

[0071] Weigh: 300 g of activated carbon and 1050 mL of acidified modified liquid, add them into the reactor and stir, raise the temperature of the reactor to 65°C, keep stirring for 5 hours, lower the temperature of the reactor to room temperature, filter, wash the filter cake with purified water until it is neutral and then dry, transfer the filter cake to a drying oven at a temperature of 75°C, dry to constant weight, and obtain acidified activated carbon.

[0072] S3. Preparation of loaded activated carbon

[0073] Weigh: 60 g zinc nitrate, 20 g magnesium nitrate, 80 g urea, and 1000 mL methanol, add them into a reactor, stir at room temperature until the system is dissolved, add 240 g acidified activated carbon into the reactor, ultrasonically disperse for 50 min, raise the temperature of the reactor to 55°C, and evaporate the solvent under reduced pressure to obtain a loaded activated carbon precursor;

[0074] The loaded activated carbon was placed in a muffle furnace, the temperature of the muffle furnace was increased to 235°C, and the temperature was kept warm for 200 minutes. The temperature of the muffle furnace was increased to 375°C, and the temperature was kept warm for 230 minutes. The material was cooled, discharged, crushed, and passed through a 100-mesh sieve to obtain the loaded activated carbon.

[0075] S4. Preparation of sol

[0076] Weigh: 200 g of ethyl orthosilicate, 1000 mL of anhydrous ethanol and 200 mL of 1.0 mol / L nitric acid solution, add into a reaction kettle and stir at room temperature for 25 min to obtain silica sol.

[0077] S5. Preparation of desulfurizing agent

[0078] The molten salt etched modified kaolin, loaded activated carbon and sol were added into the reactor in a weight ratio of 8.5:14:60, and stirred at room temperature for 2.5 hours to obtain a mixed glue solution;

[0079] Sodium lauryl sulfate, Tween-80, Span 20, purified water and anhydrous ethanol were mixed uniformly in a ratio of 4g:2g:1g:60mL:40mL to obtain an emulsion;

[0080] The emulsion was added into the reactor and stirred. The stirring speed was set to 600 r / min. The mixed rubber solution was added dropwise into the reactor. After the addition was completed, it was aged for 4 hours and filtered. The filter cake was washed with purified water until it was neutral and then dried. The filter cake was transferred to a drying oven at a temperature of 85°C and vacuum dried to constant weight to obtain a desulfurizer, wherein the volume ratio of the emulsion and the mixed rubber solution was 5:1.

[0081] Example 3

[0082] This embodiment provides a method for preparing a desulfurizing agent, comprising the following steps:

[0083] S1. Preparation of molten salt etched modified kaolin

[0084] Weigh: 700 g potassium carbonate, 1300 g potassium nitrate, and 200 g kaolin, add them into a ball mill, and pass through a 100-mesh sieve after ball milling to obtain a mixed powder;

[0085] The mixed powder was placed in a muffle furnace, the temperature of the muffle furnace was raised to 380°C, and the mixture was calcined for 4 hours, and then post-treated to obtain calcined modified kaolin;

[0086] Weigh: 500 g of calcined modified kaolin, 5000 mL of purified water, 150 g of sodium hexametaphosphate and 200 mL of 8 mol / L nitric acid, add into the reactor and stir, raise the temperature of the reactor to 70°C, keep warm and stir for 60 minutes, lower the temperature of the reactor to room temperature, filter, wash the filter cake with purified water until it is neutral and then dry, transfer the filter cake to a drying oven at 80°C, dry to constant weight, crush, and pass through a 100-mesh sieve to obtain molten salt etched modified kaolin.

[0087] S2. Preparation of acidified activated carbon

[0088] 7 mol / L nitric acid and 12 wt % hydrogen peroxide were mixed uniformly in a volume ratio of 5:1 to obtain an acidified modified solution;

[0089] Weigh: 300 g of activated carbon and 1050 mL of acidified modified liquid are added to the reactor and stirred. The temperature of the reactor is raised to 70°C, and the mixture is kept warm and stirred for 6 hours. The temperature of the reactor is lowered to room temperature, filtered, and the filter cake is washed with purified water until it is neutral and then dried. The filter cake is transferred to a drying oven at 80°C and dried to constant weight to obtain acidified activated carbon.

[0090] S3. Preparation of loaded activated carbon

[0091] Weigh: 60 g zinc nitrate, 20 g magnesium nitrate, 80 g urea, and 1000 mL methanol, add them into a reactor, stir at room temperature until the system is dissolved, add 240 g acidified activated carbon into the reactor, ultrasonically disperse for 60 min, raise the temperature of the reactor to 60°C, and evaporate the solvent under reduced pressure to obtain a loaded activated carbon precursor;

[0092] The loaded activated carbon was placed in a muffle furnace, the temperature of the muffle furnace was increased to 260°C, and the temperature was kept warm for 220 minutes. The temperature of the muffle furnace was increased to 400°C, and the temperature was kept warm for 260 minutes. The material was cooled, discharged, crushed, and passed through a 100-mesh sieve to obtain the loaded activated carbon.

[0093] S4. Preparation of sol

[0094] Weigh: 200 g of tetraethyl orthosilicate, 1000 mL of anhydrous ethanol and 200 mL of 1.2 mol / L nitric acid solution, add into a reaction kettle and stir at room temperature for 30 min to obtain silica sol.

[0095] S5. Preparation of desulfurizing agent

[0096] The molten salt etched modified kaolin, loaded activated carbon and sol were added into the reactor in a weight ratio of 9:15:60, and stirred at room temperature for 3 hours to obtain a mixed glue solution;

[0097] Sodium lauryl sulfate, Tween-80, Span 20, purified water and anhydrous ethanol were mixed uniformly in a ratio of 4g:2g:1g:60mL:40mL to obtain an emulsion;

[0098] The emulsion was added into the reactor and stirred. The stirring speed was set to 620 r / min. The mixed rubber solution was added dropwise into the reactor. After the addition was completed, it was aged for 5 hours and filtered. The filter cake was washed with purified water until it was neutral and then dried. The filter cake was transferred to a drying oven at a temperature of 90°C and vacuum dried to constant weight to obtain a desulfurizer, wherein the volume ratio of the emulsion and the mixed rubber solution was 5:1.

[0099] Example 4

[0100] This embodiment provides a desulfurization method using a desulfurizing agent, comprising the following steps:

[0101] Step 1: Fill the desulfurization agent prepared in Example 1 into two desulfurization tanks 1 layer by layer to form 8 stacked desulfurization beds in the desulfurization tank 1. The thickness of the desulfurization bed is 10 cm, and the distance between two adjacent desulfurization beds is 8 cm.

[0102] Step 2: A main air inlet pipe is provided at the top of the two desulfurization tanks 1, one end of which is connected to the top of the two desulfurization tanks 1 through two air inlet branches, and a solenoid valve 2 is installed on the two air inlet branches. A main air outlet pipe is provided at the bottom of the two desulfurization tanks 1, one end of which is connected to the bottom of the two desulfurization tanks 1 through two air outlet branches, and an air outlet check valve 3 and a point-type hydrogen sulfide detector 4 of model DS800 are installed on the two air outlet branches;

[0103] Step 3: During operation, a solenoid valve 2 on one of the air inlet branches is opened, and the mixed gas containing hydrogen sulfide is transported from the air inlet pipe at the top of the desulfurization tank 1 to the desulfurization tank 1, and then passes through multiple shedding beds for adsorption and desulfurization, and then is discharged from the air outlet pipe at the bottom of the desulfurization tank 1;

[0104] Step 4: The point-type hydrogen sulfide detector 4 installed on the outlet branch pipe monitors the hydrogen sulfide content of the gas in the outlet branch pipe in real time and feeds back the signal to the external PLC controller. When the point-type hydrogen sulfide detector 4 detects that the sulfur content in the gas discharged from the outlet pipe is higher than 0.2ppm, the PLC controller gives a signal to the two one-way valves 3 according to the feedback signal of the point-type hydrogen sulfide detector 4, closes the one-way valve 3 that is in an open state at this time, opens the other one-way valve 3 that is in a closed state, and issues a continuous alarm to remind the replacement of the desulfurizer in the desulfurization tank 1.

[0105] Example 5

[0106] The difference between this embodiment and embodiment 4 is that the desulfurizing agent used is prepared by embodiment 2.

[0107] Example 6

[0108] The difference between this embodiment and embodiment 4 is that the desulfurizing agent used is prepared by embodiment 3.

[0109] Comparative Example 1

[0110] The difference between this comparative example and Example 6 is that, when preparing the desulfurizer in Example 3, step S1 is omitted, and the molten salt-etched modified kaolin in step S5 is replaced by the kaolin in step S1.

[0111] Comparative Example 2

[0112] The difference between this comparative example and Example 6 is that, when preparing the desulfurizing agent in Example 3, step S2 is eliminated, and the activated carbon in step S2 is used instead of the acidified activated carbon in step S3.

[0113] Comparative Example 3

[0114] The difference between this comparative example and Example 6 is that, when preparing the desulfurizing agent in Example 3, no urea is added in step S3.

[0115] Comparative Example 4

[0116] The difference between this comparative example and Example 6 is that, in Example 3, when preparing the desulfurizing agent, magnesium nitrate is not added in step S3.

[0117] Performance Testing:

[0118] The sulfur capacity of the desulfurizer used in Examples 4-6 and Comparative Examples 1-4 was determined with reference to standard HG / T 5031-2016 "Sulfur Capacity Test Method for Normal Temperature Activated Carbon Alkali Desulfurizer";

[0119] The specific surface areas of the desulfurizers used in Examples 4-6 and Comparative Examples 1-4 were determined with reference to the standard GB / T 21650.3-2011 “Mercury intrusion and gas adsorption method for pore size distribution and porosity of solid materials Part 3: Micropore analysis by gas adsorption method”;

[0120] The desulfurization efficiency of the desulfurization tanks for the mixed gas containing hydrogen sulfide in Examples 4-6 and Comparative Examples 1-4 was measured with reference to the standard GB / T 21508-2008 "Method for testing the performance of coal-fired flue gas desulfurization equipment";

[0121] The specific test results are shown in Table 1 below.

[0122] Table 1-Performance test data of the sample

[0123]

[0124] Data Analysis:

[0125] Comparing and analyzing the data in Table 1 above, the sulfur capacity of the desulfurizer prepared by the present invention reaches 193.3 mg / g, and the specific surface area reaches 472.2 m 2 / g, the desulfurization efficiency of the desulfurization agent reached 96.7%, and all performance test data were better than those of the comparative example, indicating that the present invention modified kaolin by molten salt etching, prepared activated carbon loaded with zinc and magnesium metal oxides and nitrides as a base material, and then used silica sol as an auxiliary agent, and after emulsification and granulation, not only the sulfur capacity and specific surface area of ​​the desulfurizer were effectively improved, but also the desulfurization efficiency of the desulfurization agent was improved.

[0126] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

[0127] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0128] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A desulfurizing agent, characterized in that: The desulfurizer is prepared by emulsifying and granulating a mixed colloid solution of molten salt-etched modified kaolin, loaded activated carbon and sol in a weight ratio of 8-9:13-15:60; The emulsification granulation method is as follows: adding the emulsion into the reactor and stirring, setting the stirring speed to 580-620 r / min, dripping the mixed glue into the reactor, aging for 3-5 hours after the dripping is completed, and post-processing to obtain the desulfurizer; Molten salt etched modified kaolin is processed by the following steps: A1. Add potassium carbonate, potassium nitrate and kaolin into a ball mill, and pass through a 100-mesh sieve after ball milling to obtain a mixed powder; A2. Place the mixed powder in a muffle furnace, raise the temperature of the muffle furnace to 360-380°C, keep the temperature and roast for 3-4 hours, and post-treat to obtain roasted modified kaolin; A3, adding roasted modified kaolin, purified water, sodium hexametaphosphate and nitric acid into a reactor and stirring, raising the temperature of the reactor to 60-70° C., keeping the temperature and stirring for 40-60 minutes, and post-treating to obtain molten salt etched modified kaolin; The loaded activated carbon is processed by the following steps: B1. Add zinc nitrate, magnesium nitrate, urea and methanol into a reactor, stir at room temperature until the system is dissolved, add acidified activated carbon into the reactor, ultrasonically disperse for 40-60 minutes, and post-treat to obtain a loaded activated carbon precursor; B2, placing the loaded activated carbon in a muffle furnace, raising the temperature of the muffle furnace to 210-260°C, and heat preservation for 180-220min, raising the temperature of the muffle furnace to 350-400°C, and heat preservation for 200-260min, cooling the material, discharging the material, crushing it, and passing it through a 100-mesh sieve to obtain the loaded activated carbon; The preparation method of the sol is as follows: adding tetraethyl orthosilicate, anhydrous ethanol and nitric acid solution into a reaction kettle and stirring, stirring at room temperature for 20-30 minutes to obtain silica sol, wherein the dosage ratio of tetraethyl orthosilicate, anhydrous ethanol and nitric acid solution is 1g:5mL:1mL, and the concentration of the nitric acid solution is 0.8-1.2mol / L.

2. A desulfurizing agent according to claim 1, characterized in that: The emulsion is composed of sodium dodecyl sulfate, Tween-80, Span 20, purified water and anhydrous ethanol in a dosage ratio of 4g:2g:1g:60mL:40mL, and the volume ratio of the emulsion to the mixed glue is 5:

1. The post-treatment includes: after aging, suction filtration, washing the filter cake with purified water until it is neutral and then drying it, transferring the filter cake to a drying oven with a temperature of 80-90°C, and vacuum drying it to constant weight to obtain a desulfurizer.

3. A desulfurizing agent according to claim 1, characterized in that: In step A1, the weight ratio of potassium carbonate, potassium nitrate and kaolin is 7:13:2; in step A3, the amount ratio of the roasted modified kaolin, purified water, sodium hexametaphosphate and nitric acid is 10g:100mL:3g:4mL, and the concentration of the nitric acid is 6-8mol / L. The post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, filtered, the filter cake is washed with purified water until it is neutral and then dried, and the filter cake is transferred to a drying oven at a temperature of 70-80°C, dried to constant weight, crushed, and passed through a 100-mesh sieve to obtain molten salt etched modified kaolin.

4. A desulfurizing agent according to claim 1, characterized in that: In step B1, the amount ratio of zinc nitrate, magnesium nitrate, urea, methanol and acidified activated carbon is 3g:1g:4g:50mL:12g, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is increased to 50-60°C, and the solvent is evaporated under reduced pressure to obtain a loaded activated carbon precursor.

5. A desulfurizing agent according to claim 1, characterized in that: The preparation method of acidified activated carbon is as follows: activated carbon and acidified modified liquid are added into a reactor and stirred, the temperature of the reactor is increased to 60-70° C., the reactor is kept warm and stirred for 4-6 hours, and the acidified activated carbon is obtained by post-treatment.

6. A desulfurizing agent according to claim 5, characterized in that: The dosage ratio of the activated carbon and the acidified modification liquid is 2g:7mL, the acidified modification liquid is composed of 5-7mol / L nitric acid and 10-12wt% hydrogen peroxide in a volume ratio of 5:1, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the filter is filtered, the filter cake is washed with purified water until it is neutral and then dried, the filter cake is transferred to a drying oven at a temperature of 70-80°C, and dried to constant weight to obtain acidified activated carbon.

7. A desulfurization method using the desulfurizing agent according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Filling the prepared desulfurizing agent into two desulfurizing tanks (1) layer by layer, so as to form a plurality of stacked desulfurizing beds in the desulfurizing tanks (1); When S2 is in operation, a solenoid valve (2) on the air inlet pipe is opened, and the mixed gas containing hydrogen sulfide is transported from the air inlet pipe at the top of the desulfurization tank (1) into the desulfurization tank (1), and then passes through multiple shedding beds for adsorption and desulfurization, and then is discharged from the air outlet pipe at the bottom of the desulfurization tank (1); S3. The point-type hydrogen sulfide detector (4) installed on the outlet pipe monitors the exhaust gas in real time. When the sulfur content in the gas discharged from the outlet pipe is higher than 0.2 ppm, the one-way valve (3) that is in the open state is closed through signal feedback, and then the other one-way valve (3) that is in the closed state is opened, and a continuous alarm is issued.

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