Preparation method of high-pore-volume calcium-based particle desulfurizer

Abstract

The invention relates to the technical field of desulfurizing agents, in particular to a preparation method of a high-pore-volume calcium-based particle desulfurizing agent. Comprising the following steps: (1) preparing carboxymethyl cellulose loaded with calcium carbonate; (2) grafting and modifying cellulose through polyethylene glycol; (3) introducing a zinc acetate solution to prepare modified cellulose; (4) mixing calcium carbonate powder, modified cellulose and the like to prepare slurry; (5) granulating by adopting a fluidized bed to form particles; and (6) preparing the high-pore-volume calcium-based desulfurizing agent under an optimized calcining process. According to the desulfurizer, the pore structure is optimized through cellulose functional modification, polyethylene glycol grafting and zinc ion introduction, the mechanical strength is enhanced, the desulfurizer with high pore volume, high mechanical strength and excellent cycle stability is finally obtained, and the desulfurizer is suitable for removing hydrogen sulfide in industrial waste gas and natural gas and has good industrial application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of desulfurizing agents, and particularly to a preparation method of a calcium-based granular desulfurizing agent with high pore volume. Background Art

[0002] With the acceleration of the industrialization process, the widespread use of fossil energy has led to an increasingly serious problem of sulfide pollution. Hydrogen sulfide (H 2 S), as a common sulfur-containing compound, not only has strong corrosiveness and toxicity, but also poses a serious threat to the environment and human health. Therefore, how to efficiently remove hydrogen sulfide from industrial waste gas and natural gas has become an important research topic in the current fields of environmental protection and energy purification. Calcium-based desulfurizing agents have attracted much attention due to their rich resources, low cost, and excellent environmental protection performance. However, traditional calcium-based desulfurizing agents have many problems in practical applications, such as underdeveloped pore structure, insufficient mechanical strength, poor recycling performance, etc., which limit their wide application in industry.

[0003] Currently, the preparation of calcium-based desulfurizing agents is mainly achieved through means such as physical mixing, chemical modification, and high-temperature calcination. Traditional preparation methods usually use a single calcium-based compound as the raw material and prepare the desulfurizing agent through simple granulation and calcination processes. However, the calcium-based desulfurizing agents prepared by this method often have problems such as low pore volume and limited specific surface area, and it is difficult to meet the requirements for efficient adsorption of hydrogen sulfide. In addition, calcium-based desulfurizing agents are prone to particle breakage and pore collapse during use, resulting in a significant decrease in mechanical strength and recycling stability. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to propose a preparation method of a calcium-based granular desulfurizing agent with high pore volume, so as to provide a calcium-based desulfurizing agent with high pore volume, high mechanical strength, and excellent recycling stability.

[0005] Based on the above purpose, the present invention provides a preparation method of a calcium-based granular desulfurizing agent with high pore volume, including the following steps:

[0006] (1) Add calcium chloride and sodium carboxymethylcellulose to deionized water, stir at room temperature for 50 - 70 min, then add a sodium carbonate aqueous solution with a concentration of 8 - 12 wt%, stir at room temperature for 20 - 40 min, and purify to obtain carboxymethylcellulose loaded with calcium carbonate;

[0007] (2) Add the carboxymethylcellulose loaded with calcium carbonate to cyclohexane, stir for 15 - 25 min, then add polyethylene glycol monomethyl ether and p-toluenesulfonic acid, raise the temperature to 80 - 90 °C, and reflux and stir for reaction for 5 - 7 h, and purify to obtain polyethylene glycol grafted cellulose;

[0008] (3) Add the polyethylene glycol grafted cellulose into an aqueous solution of zinc acetate with a concentration of 4-6 wt%, stir at room temperature for 60-84 h, and purify to obtain the modified cellulose;

[0009] (4) Add the calcium carbonate powder, modified cellulose and sodium carboxymethylcellulose into deionized water, and stir for 10-20 min to obtain a slurry;

[0010] (5) Granulate the slurry by fluidized bed to obtain microparticles with a particle size D50 of 1.3-1.8 mm;

[0011] (6) Place the microparticles in a muffle furnace and calcine to obtain a high pore volume calcium-based desulfurizer.

[0012] Preferably, the degree of substitution of the sodium carboxymethylcellulose in the step (1) is 0.8-0.9.

[0013] Preferably, the weight ratio of calcium chloride, sodium carboxymethylcellulose, deionized water and sodium carbonate aqueous solution in the step (1) is 30-50:120-180:1000-1500:400-600.

[0014] Preferably, the weight ratio of the carboxymethylcellulose loaded with calcium carbonate, cyclohexane, methoxypolyethylene glycol and p-toluenesulfonic acid in the step (2) is 120-180:600-1000:40-60:5-10.

[0015] Preferably, the weight-average molecular weight of the methoxypolyethylene glycol in the step (2) is 3000-5000.

[0016] Preferably, the weight ratio of the polyethylene glycol grafted cellulose and the zinc acetate aqueous solution in the step (3) is 150-250:300-800.

[0017] Preferably, the weight ratio of the calcium carbonate powder, modified cellulose, sodium carboxymethylcellulose and deionized water in the step (4) is 300-500:80-120:8-12:150-250.

[0018] Preferably, the mesh number of the calcium carbonate powder in the step (4) is 200-400 mesh.

[0019] Preferably, in the step (5), the nozzle diameter of the fluidized bed granulation is 0.7-0.9 mm, the fluidization gas velocity is 0.6-1 m / s, the inlet air temperature is 55-65 °C, the outlet air temperature is 35-40 °C, the atomization pressure is 0.2-0.3 MPa, and the bottom spray height is 80-120 mm.

[0020] Preferably, in step (6), the calcination is carried out in a nitrogen atmosphere. The temperature is raised to 430-480°C at a rate of 4-6°C / min, held for 0.8-1.2 h, then raised to 830-880°C at a rate of 1-3°C / min, held for 1.5-2.5 h, and cooled with the furnace.

[0021] Advantages of the present invention:

[0022] Through the composite modification of cellulose and calcium-based compounds and the optimized calcination process, the present invention prepares a calcium-based desulfurizer with high pore volume, high mechanical strength, and excellent cyclic stability. This desulfurizer shows significant advantages in many aspects. First, through the functional modification of cellulose and the loading of calcium-based compounds, a porous material with a rich pore structure is formed after calcination. The introduction of the porous structure not only significantly increases the specific surface area of the material but also provides more active sites for the adsorption and reaction of hydrogen sulfide, thus enhancing the adsorption capacity and reaction activity of the desulfurizer.

[0023] Secondly, through the graft modification of polyethylene glycol, the pore structure and framework stability of the material are further optimized. During the calcination process, polyethylene glycol forms a stable pore network structure through thermal decomposition and cross-linking reactions, and at the same time introduces more active sites on the material surface, significantly improving the comprehensive performance of the desulfurizer. In addition, the grafting method of polyethylene glycol has higher stability compared to the physical mixing method, effectively avoiding the non-uniformity and migration of the pore structure during the calcination process, thereby further improving the pore development degree and stability of the material.

[0024] In addition, through the introduction of zinc ions, a composite interface is formed during the high-temperature calcination process, further enhancing the mechanical strength and cyclic stability of the material. The coordination structure of zinc ions is transformed into a composite interface at high temperature, forming a "pinning effect", significantly improving the compressive performance of the particles. At the same time, zinc ions also promote the graphitization transformation of the carbon layer in the framework, thereby further improving the mechanical properties of the material. This optimized structural design enables the desulfurizer to have less performance degradation during multiple desulfurization-regeneration cycles, showing excellent stability.

[0025] In summary, the calcium-based desulfurizer prepared by the present invention shows significant advantages in terms of desulfurization efficiency, mechanical strength, and cyclic stability, and has broad industrial application prospects. Specific embodiments

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the following further details the present invention with specific embodiments.

[0027] Example 1:

[0028] (1) Add 30 g of calcium chloride and 120 g of sodium carboxymethylcellulose (degree of substitution 0.85) to 1000 g of deionized water, stir at room temperature for 50 min, then add 400 g of an aqueous sodium carbonate solution with a concentration of 8 wt%, stir at room temperature for 20 min, centrifuge, wash 3 times with deionized water, and dry in vacuum to obtain carboxymethylcellulose loaded with calcium carbonate;

[0029] (2) Add 120 g of carboxymethylcellulose loaded with calcium carbonate to 600 g of cyclohexane, stir for 15 min, then add 40 g of polyethylene glycol monomethyl ether (weight-average molecular weight of 3000) and 5 g of p-toluenesulfonic acid, raise the temperature to 80 °C, reflux and stir for 5 h, cool down, centrifuge, wash 3 times with ethanol, and dry in vacuum to obtain polyethylene glycol-grafted cellulose;

[0030] (3) Add 150 g of polyethylene glycol-grafted cellulose to 300 g of an aqueous zinc acetate solution with a concentration of 4 wt%, stir at room temperature for 60 h, centrifuge, wash 3 times with deionized water, and dry in vacuum to obtain modified cellulose;

[0031] (4) Add 300 g of calcium carbonate powder (325 mesh), 80 g of modified cellulose, and 8 g of sodium carboxymethylcellulose to 150 g of deionized water, and stir at a speed of 250 rpm for 10 min to obtain a slurry;

[0032] (5) Granulate the slurry by fluidized bed granulation, with a nozzle diameter of 0.7 mm, a fluidization gas velocity of 0.6 m / s, an inlet air temperature of 55 °C, an outlet air temperature of 35 °C, an atomization pressure of 0.2 MPa, and a bottom spray height of 80 mm to obtain particles with a D50 particle size of 1.3 mm;

[0033] (6) Place the particles in a muffle furnace, under a nitrogen atmosphere, heat up to 430 °C at a rate of 4 °C / min, hold for 0.8 h, heat up to 830 °C at a rate of 1 °C / min, hold for 1.5 h, and cool down with the furnace to obtain a high-porosity calcium-based desulfurizer.

[0034] Example 2:

[0035] (1) Add 40 g of calcium chloride and 150 g of sodium carboxymethylcellulose (degree of substitution 0.85) to 1200 g of deionized water, stir at room temperature for 60 min, then add 500 g of an aqueous sodium carbonate solution with a concentration of 10 wt%, stir at room temperature for 30 min, centrifuge, wash 3 times with deionized water, and dry in vacuum to obtain carboxymethylcellulose loaded with calcium carbonate;

[0036] (2) Add 150 g of carboxymethyl cellulose loaded with calcium carbonate to 800 g of cyclohexane, stir for 20 min, then add 50 g of polyethylene glycol monomethyl ether (weight average molecular weight of 4000) and 7.5 g of p-toluenesulfonic acid, heat up to 85 °C, reflux and stir for 6 h, cool down, centrifuge, wash with ethanol 3 times, and dry under vacuum to obtain polyethylene glycol grafted cellulose;

[0037] (3) Add 200 g of polyethylene glycol grafted cellulose to 500 g of an aqueous solution of zinc acetate with a concentration of 5 wt%, stir at room temperature for 72 h, centrifuge, wash with deionized water 3 times, and dry under vacuum to obtain modified cellulose;

[0038] (4) Add 400 g of calcium carbonate powder (325 mesh), 100 g of modified cellulose, and 10 g of sodium carboxymethyl cellulose to 200 g of deionized water, stir at a speed of 300 rpm for 15 min to obtain a slurry;

[0039] (5) Granulate the slurry by fluidized bed, with a nozzle diameter of 0.8 mm, a fluidization gas velocity of 0.8 m / s, an inlet air temperature of 60 °C, an outlet air temperature of 38 °C, an atomization pressure of 0.25 MPa, and a bottom spray height of 100 mm to obtain particles with a D50 particle size of 1.5 mm;

[0040] (6) Place the particles in a muffle furnace, under a nitrogen atmosphere, heat up to 450 °C at a rate of 5 °C / min, hold for 1 h, heat up to 850 °C at a rate of 2 °C / min, hold for 2 h, and cool down with the furnace to obtain a high pore volume calcium-based desulfurizer.

[0041] Example 3:

[0042] (1) Add 50 g of calcium chloride and 180 g of sodium carboxymethyl cellulose (degree of substitution 0.85) to 1500 g of deionized water, stir at room temperature for 70 min, then add 600 g of an aqueous solution of sodium carbonate with a concentration of 12 wt%, stir at room temperature for 40 min, centrifuge, wash with deionized water 3 times, and dry under vacuum to obtain carboxymethyl cellulose loaded with calcium carbonate;

[0043] (2) Add 180 g of carboxymethyl cellulose loaded with calcium carbonate to 1000 g of cyclohexane, stir for 25 min, then add 60 g of polyethylene glycol monomethyl ether (weight average molecular weight of 5000) and 10 g of p-toluenesulfonic acid, heat up to 90 °C, reflux and stir for 7 h, cool down, centrifuge, wash with ethanol 3 times, and dry under vacuum to obtain polyethylene glycol grafted cellulose;

[0044] (3) Add 250 g of polyethylene glycol grafted cellulose to 800 g of an aqueous solution of zinc acetate with a concentration of 6 wt%, stir at room temperature for 84 h, centrifuge, wash with deionized water 3 times, and dry under vacuum to obtain modified cellulose;

[0045] (4) Add 500 g of calcium carbonate powder (325 mesh), 120 g of modified cellulose, and 12 g of sodium carboxymethyl cellulose to 250 g of deionized water, and stir at a speed of 350 rpm for 20 min to obtain a slurry;

[0046] (5) Granulate the slurry by fluidized bed granulation, with a nozzle diameter of 0.9 mm, a fluidization gas velocity of 1 m / s, an inlet air temperature of 65 °C, an outlet air temperature of 40 °C, an atomization pressure of 0.3 MPa, and a bottom spray height of 120 mm to obtain fine particles with a D50 particle size of 1.8 mm;

[0047] (6) Place the fine particles in a muffle furnace, under a nitrogen atmosphere, heat up to 480 °C at a rate of 6 °C / min, hold for 1.2 h, heat up to 880 °C at a rate of 3 °C / min, hold for 2.5 h, and cool down with the furnace to obtain a high pore volume calcium-based desulfurizer.

[0048] Comparative Example 1:

[0049] The difference between Comparative Example 1 and Example 2 is that the carboxymethyl cellulose loaded with calcium carbonate in step (2) is replaced with sodium carboxymethyl cellulose (degree of substitution 0.85);

[0050] The specific steps are as follows:

[0051] (1) Add 150 g of sodium carboxymethyl cellulose (degree of substitution 0.85) to 800 g of cyclohexane, stir for 20 min, then add 50 g of methoxypolyethylene glycol (weight average molecular weight of 4000) and 7.5 g of p-toluenesulfonic acid, heat up to 85 °C, reflux and stir for 6 h, cool down, centrifuge, wash with ethanol 3 times, and vacuum dry to obtain polyethylene glycol grafted cellulose;

[0052] (2) Add 200 g of polyethylene glycol grafted cellulose to 500 g of an aqueous zinc acetate solution with a concentration of 5 wt%, stir at room temperature for 72 h, centrifuge, wash with deionized water 3 times, and vacuum dry to obtain modified cellulose;

[0053] (3) Add 400 g of calcium carbonate powder (325 mesh), 100 g of modified cellulose, and 10 g of sodium carboxymethyl cellulose to 200 g of deionized water, and stir at a speed of 300 rpm for 15 min to obtain a slurry;

[0054] (4) Granulate the slurry by fluidized bed granulation, with a nozzle diameter of 0.8 mm, a fluidization gas velocity of 0.8 m / s, an inlet air temperature of 60 °C, an outlet air temperature of 38 °C, an atomization pressure of 0.25 MPa, and a bottom spray height of 100 mm to obtain fine particles with a D50 particle size of 1.5 mm;

[0055] (5) Place the microparticles in a muffle furnace. Under a nitrogen atmosphere, heat them at a rate of 5 °C / min to 450 °C, hold for 1 h, then heat to 850 °C at a rate of 2 °C / min, hold for 2 h, and cool down with the furnace to obtain a calcium-based desulfurizer.

[0056] Comparative Example 2:

[0057] The difference between Comparative Example 2 and Example 2 is that the polyethylene glycol grafted cellulose in step (3) is replaced by carboxymethyl cellulose loaded with calcium carbonate;

[0058] The specific steps are as follows:

[0059] (1) Add 40 g of calcium chloride and 150 g of sodium carboxymethyl cellulose (substitution degree 0.85) to 1200 g of deionized water, stir at room temperature for 60 min, then add 500 g of a 10 wt% sodium carbonate aqueous solution, stir at room temperature for 30 min, centrifuge, wash 3 times with deionized water, and dry in vacuum to obtain carboxymethyl cellulose loaded with calcium carbonate;

[0060] (2) Add 200 g of carboxymethyl cellulose loaded with calcium carbonate to 500 g of a 5 wt% zinc acetate aqueous solution, stir at room temperature for 72 h, centrifuge, wash 3 times with deionized water, and dry in vacuum to obtain modified cellulose;

[0061] (3) Add 400 g of calcium carbonate powder (325 mesh), 100 g of modified cellulose, and 10 g of sodium carboxymethyl cellulose to 200 g of deionized water, and stir at a speed of 300 rpm for 15 min to obtain a slurry;

[0062] (4) Granulate the slurry by fluidized bed granulation, with a nozzle diameter of 0.8 mm, a fluidization gas velocity of 0.8 m / s, an inlet air temperature of 60 °C, an outlet air temperature of 38 °C, an atomization pressure of 0.25 MPa, and a bottom spray height of 100 mm to obtain microparticles with a D50 particle size of 1.5 mm;

[0063] (5) Place the microparticles in a muffle furnace. Under a nitrogen atmosphere, heat them at a rate of 5 °C / min to 450 °C, hold for 1 h, then heat to 850 °C at a rate of 2 °C / min, hold for 2 h, and cool down with the furnace to obtain a calcium-based desulfurizer.

[0064] Comparative Example 3:

[0065] The difference between Comparative Example 3 and Example 2 is that the modified cellulose in step (4) is replaced by polyethylene glycol grafted cellulose;

[0066] The specific steps are as follows:

[0067] (1) Add 40 g of calcium chloride and 150 g of sodium carboxymethyl cellulose (degree of substitution 0.85) to 1200 g of deionized water, stir at room temperature for 60 min, then add 500 g of a 10 wt% aqueous sodium carbonate solution, stir at room temperature for 30 min, centrifuge, wash three times with deionized water, and dry in vacuo to obtain calcium carbonate-loaded carboxymethyl cellulose;

[0068] (2) Add 150 g of calcium carbonate-loaded carboxymethyl cellulose to 800 g of cyclohexane, stir for 20 min, then add 50 g of methoxypolyethylene glycol (weight-average molecular weight 4000) and 7.5 g of p-toluenesulfonic acid, raise the temperature to 85 °C, reflux and stir for 6 h, cool down, centrifuge, wash three times with ethanol, and dry in vacuo to obtain polyethylene glycol-grafted cellulose;

[0069] (3) Add 400 g of calcium carbonate powder (325 mesh), 100 g of polyethylene glycol-grafted cellulose, and 10 g of sodium carboxymethyl cellulose to 200 g of deionized water, and stir at a speed of 300 rpm for 15 min to obtain a slurry;

[0070] (4) Granulate the slurry by fluidized bed granulation, with a nozzle diameter of 0.8 mm, a fluidization gas velocity of 0.8 m / s, an inlet air temperature of 60 °C, an outlet air temperature of 38 °C, an atomization pressure of 0.25 MPa, and a bottom spraying height of 100 mm to obtain particles with a D50 particle size of 1.5 mm;

[0071] (5) Place the particles in a muffle furnace, under a nitrogen atmosphere, heat up to 450 °C at a rate of 5 °C / min, hold for 1 h, heat up to 850 °C at a rate of 2 °C / min, hold for 2 h, and cool down with the furnace to obtain a calcium-based desulfurizer.

[0072] Comparative Example 4:

[0073] The difference between Comparative Example 4 and Example 2 is that the polyethylene glycol-grafted cellulose in step (3) is replaced with calcium carbonate-loaded carboxymethyl cellulose; the modified cellulose addition amount in step (4) is modified to 75 g, and 25 g of polyethylene glycol (weight-average molecular weight 4000) is added;

[0074] The specific steps are as follows:

[0075] (1) Add 40 g of calcium chloride and 150 g of sodium carboxymethyl cellulose (degree of substitution 0.85) to 1200 g of deionized water, stir at room temperature for 60 min, then add 500 g of a 10 wt% aqueous sodium carbonate solution, stir at room temperature for 30 min, centrifuge, wash three times with deionized water, and dry in vacuo to obtain calcium carbonate-loaded carboxymethyl cellulose;

[0076] (2) Add 200 g of carboxymethyl cellulose loaded with calcium carbonate to 500 g of an aqueous zinc acetate solution with a concentration of 5 wt%, stir at room temperature for 72 h, centrifuge, wash three times with deionized water, and dry under vacuum to obtain modified cellulose;

[0077] (3) Add 400 g of calcium carbonate powder (325 mesh), 75 g of modified cellulose, 25 g of polyethylene glycol (weight average molecular weight of 4000), and 10 g of sodium carboxymethyl cellulose to 200 g of deionized water, and stir at a speed of 300 rpm for 15 min to obtain a slurry;

[0078] (4) Granulate the slurry using a fluidized bed, with a nozzle diameter of 0.8 mm, a fluidization gas velocity of 0.8 m / s, an inlet air temperature of 60 °C, an outlet air temperature of 38 °C, an atomization pressure of 0.25 MPa, and a bottom spray height of 100 mm to obtain fine particles with a D50 particle size of 1.5 mm;

[0079] (5) Place the fine particles in a muffle furnace, under a nitrogen atmosphere, heat up to 450 °C at a rate of 5 °C / min, hold for 1 h, heat up to 850 °C at a rate of 2 °C / min, hold for 2 h, and cool down with the furnace to obtain a calcium-based desulfurizer.

[0080] Performance test:

[0081] Desulfurization efficiency test: According to GB / T 19208-2008, load 5.00 g of the sample into a fixed-bed reactor with a diameter of 20 mm, and under a constant temperature condition of 25 ± 1 °C, introduce a nitrogen mixed gas containing 5000 ppm of hydrogen sulfide at a flow rate of 200 mL / min. Use the iodometric method (GB / T 11060.1-2010) to measure the hydrogen sulfide concentration in the inlet and outlet gases of the reactor. Stop the test when the outlet concentration reaches 50% of the inlet concentration, record the breakthrough time, and calculate the sulfur capacity (g sulfur / 100 g desulfurizer). The results are shown in Table 1.

[0082] Pore volume test: Use a mercury intrusion porosimeter to measure the total pore volume in the pressure range of 0.1 - 400 MPa. The results are shown in Table 1.

[0083] Mechanical strength test: Randomly select 30 samples, use a universal material testing machine to perform single-particle compressive testing at a rate of 0.5 mm / min, record the maximum load when the particles break, and calculate the average compressive strength (N / particle). The results are shown in Table 1.

[0084] Regeneration performance test: Place the desulfurization-saturated sample in a tubular furnace, regenerate for 2 h under a nitrogen mixed atmosphere at 450 °C and an oxygen concentration of 3%, repeat the desulfurization-regeneration cycle 5 times, measure the sulfur capacity retention rate and mechanical strength after 5 cycles. Control the regeneration gas flow rate at 100 mL / min and set the heating rate at 5 °C / min. The results are shown in Table 1.

[0085] Table 1 Performance Test Results

[0086]

[0087] Data Analysis:

[0088] From the data of Examples 1 - 3 in Table 1, it can be seen that the high pore volume calcium-based desulfurizer prepared by the present invention shows significant advantages in comprehensive performance. Its pore volume is relatively large, indicating that the material has a high specific surface area and a rich pore structure, which helps to improve the adsorption capacity and reaction activity of the desulfurizer for hydrogen sulfide. At the same time, the material has a high compressive strength, indicating excellent mechanical properties, and it can withstand a certain external force during actual application without being easily broken, which is beneficial to extending the service life. In addition, after multiple desulfurization-regeneration cycles, both the sulfur capacity retention rate and the mechanical strength retention rate are relatively high, indicating that the performance of the desulfurizer decays less during repeated use, and it has good stability and regeneration performance.

[0089] From the data of Example 2 and Comparative Example 1 in Table 1, it can be seen that compared with Comparative Example 1, the desulfurizer of Example 2 shows more excellent performance in terms of breakthrough time, sulfur capacity, pore volume, and cyclic performance. This may be related to the introduction of carboxymethyl cellulose loaded with calcium carbonate during the preparation process. This material forms a porous structure with multiple active sites during the later calcination process, thus enhancing the adsorption capacity and reaction activity of the desulfurizer.

[0090] From the data of Example 2 and Comparative Example 2 in Table 1, it can be seen that the desulfurizer of Example 2 is superior to Comparative Example 2 in terms of desulfurization performance and cyclic stability. This may be because during the calcination process, polyethylene glycol-grafted cellulose may form a more stable pore network structure through thermal decomposition and cross-linking reactions, and at the same time introduce more active sites on the material surface, thus significantly improving the desulfurization efficiency and pore stability. In Comparative Example 2, polyethylene glycol-grafted cellulose without modification is used, which may lead to insufficient formation of the pore structure during the calcination process, thereby limiting the performance improvement of the desulfurizer.

[0091] From the data of Example 2 and Comparative Example 3 in Table 1, it can be seen that the desulfurizer of Example 2 is superior to Comparative Example 2 in terms of compressive resistance and cyclic stability. This may be because the zinc coordination structure on the cellulose molecular chain is transformed into a ZnO-CaO composite interface at high temperature, forming a "pinning effect", significantly improving the mechanical strength, and zinc further promotes the transformation of the carbon layer in the framework to graphitization, further improving the mechanical strength. In Comparative Example 3, unmodified polyethylene glycol-grafted cellulose is used, lacking the interface strengthening effect and catalytic effect of zinc ions during calcination, resulting in weak binding force inside the particles and the collapse of the framework during the regeneration cycle, thus affecting the cyclic stability.

[0092] From the data of Example 2 and Comparative Example 4 in Table 1, it can be seen that the desulfurizer in Example 2 performs better in terms of sulfur capacity, pore volume and cyclic performance, which may be closely related to the adaptability of the graft modification method of polyethylene glycol to the calcination process. In Comparative Example 4, polyethylene glycol was used for blending instead of graft modification, and its physical mixing method may lead to the decomposition or migration of polyethylene glycol during calcination, thereby affecting the uniformity and stability of the pore structure. In contrast, in Example 2, polyethylene glycol was fixed on the cellulose skeleton by chemical grafting, and a more stable cross-linked network structure may be formed during calcination, thus effectively regulating pore development.

[0093] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is exemplary only and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, and they are not provided in detail for the sake of brevity.

Claims

1. A method for preparing a high pore volume calcium-based granular desulfurizer, characterized in that: The following steps are involved: (1) adding calcium chloride and sodium carboxymethyl cellulose to deionized water, stirring at room temperature for 50-70 minutes, then adding an aqueous sodium carbonate solution with a concentration of 8-12 wt%, stirring at room temperature for 20-40 minutes, and purifying to obtain carboxymethyl cellulose loaded with calcium carbonate; (2) adding carboxymethyl cellulose loaded with calcium carbonate to cyclohexane, stirring for 15-25 minutes, then adding polyethylene glycol monomethyl ether and p-toluenesulfonic acid, heating to 80-90° C., reflux stirring for reaction for 5-7 hours, and purifying to obtain polyethylene glycol grafted cellulose; (3) adding the polyethylene glycol grafted cellulose to a 4-6 wt % aqueous zinc acetate solution, stirring at room temperature for 60-84 h, and purifying to obtain modified cellulose; (4) adding calcium carbonate powder, modified cellulose and sodium carboxymethyl cellulose into deionized water and stirring for 10-20 minutes to obtain a slurry; (5) granulating the slurry using a fluidized bed to obtain particles with a particle size D50 of 1.3-1.8 mm; (6) placing the microparticles in a muffle furnace and calcining them to obtain a high pore volume calcium-based desulfurizer; In the step (1), the weight ratio of calcium chloride, sodium carboxymethyl cellulose, deionized water and sodium carbonate aqueous solution is 30-50:120-180:1000-1500:400-600; In the step (2), the weight ratio of carboxymethyl cellulose, cyclohexane, polyethylene glycol monomethyl ether and p-toluenesulfonic acid loaded with calcium carbonate is 120-180:600-1000:40-60:5-10; The weight average molecular weight of polyethylene glycol monomethyl ether in step (2) is 3000-5000; In the step (3), the weight ratio of polyethylene glycol grafted cellulose to zinc acetate aqueous solution is 150-250:300-800; In the step (4), the weight ratio of calcium carbonate powder, modified cellulose, sodium carboxymethyl cellulose and deionized water is 300-500:80-120:8-12:150-250.

2. The method for preparing a high pore volume calcium-based granular desulfurizer according to claim 1, characterized in that: The degree of substitution of sodium carboxymethyl cellulose in step (1) is 0.8-0.

9.

3. The method for preparing a high pore volume calcium-based granular desulfurizer according to claim 1, characterized in that: The mesh size of the calcium carbonate powder in the step (4) is 200-400 meshes.

4. The method for preparing a high pore volume calcium-based granular desulfurizer according to claim 1, characterized in that: In the step (5), the nozzle diameter of the fluidized bed granulation is 0.7-0.9 mm, the fluidizing gas velocity is 0.6-1 m / s, the inlet air temperature is 55-65° C., the outlet air temperature is 35-40° C., the atomization pressure is 0.2-0.3 MPa, and the bottom spray height is 80-120 mm.

5. The method for preparing a high pore volume calcium-based granular desulfurizer according to claim 1, characterized in that: The calcination in step (6) is carried out under a nitrogen atmosphere, heating to 430-480°C at a rate of 4-6°C / min, keeping the temperature for 0.8-1.2h, heating to 830-880°C at a rate of 1-3°C / min, keeping the temperature for 1.5-2.5h, and cooling with the furnace.

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