Method for preparing P-ZSM-5 molecular sieve from yellow phosphorus slag and application of P-ZSM-5 molecular sieve
By preparing yellow phosphorus slag as P-ZSM-5 molecular sieve and applying it to methanol to propylene reaction, the problems of yellow phosphorus slag accumulation and ZSM-5 molecular sieve catalyst deactivation were solved, and efficient catalytic performance and effective utilization of resources were achieved.
Patent Information
- Application Number
- CN202411666671.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-02-25
AI Technical Summary
The accumulation of yellow phosphorus slag leads to land occupation and environmental pollution. At the same time, the existing ZSM-5 molecular sieves have problems of coke deposition and rapid catalyst deactivation in the catalytic reaction.
P-ZSM-5 molecular sieves were prepared by the steps of acid leaching, aging, hydrothermal crystallization, calcining, ion exchange and recalcining, and applied to the methanol-to-propylene reaction.
Effectively use yellow phosphorus furnace slag to prepare high-quality P-ZSM-5 molecular sieve, which improves the hydrothermal stability and catalytic performance of the catalyst, extends the life of the catalyst, and reduces the raw material cost of molecular sieve preparation.
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Abstract
Description
Technical Field
[0001] The invention relates to the field of molecular sieve preparation technology and secondary utilization of solid waste, and in particular to a method for preparing a P-ZSM-5 molecular sieve by using yellow phosphorus slag and application thereof in a methanol-to-propylene reaction. Background Art
[0002] When yellow phosphorus is produced by the electric furnace method, apatite, quartz, and coke are melted at about 1400℃ in an electric arc furnace, and the waste slag discharged by water quenching is called yellow phosphorus slag. Its main component is calcium silicate, which has high reactivity. For every ton of yellow phosphorus produced, 8 to 10 tons of yellow phosphorus slag are discharged, resulting in a large amount of yellow phosphorus slag accumulation. Its storage and treatment not only occupies a large area of land, but also long-term storage will cause toxic substances to flow into the land and groundwater, causing serious harm to the environment. At present, the uses of yellow phosphorus slag mainly involve white carbon black, microcrystalline glass, ceramics, concrete, fired bricks and cement. Therefore, using yellow phosphorus slag to produce high value-added products is a good development direction.
[0003] ZSM-5 molecular sieve is a new type of high silicon-aluminum ratio zeolite molecular sieve developed by Mobil Oil Company in the United States in 1972. It belongs to the MFI topology. It has unique shape selectivity, thermal stability and acid resistance. Its traditional application areas include: catalytic cracking reaction, methanol to hydrocarbon reaction, alkylation to produce toluene, and isomerization reaction. Methanol-to-Propylene (MTP) inherits the mature coal-to-methanol (CTM) process, which can not only achieve the clean utilization of coal resources but also increase propylene production, and thus has received widespread attention. ZSM-5 zeolite has become the preferred catalyst for MTP reaction due to its unique pore structure and adjustable acid catalytic active center. However, ordinary ZSM-5 zeolite faces the problems of severe coke deposition and rapid catalyst deactivation during the catalytic reaction. Studies have shown that the use of phosphorus to modify ZSM-5 molecular sieve can effectively improve its acidity and improve its hydrothermal stability, thereby reducing the deactivation of the catalyst. At present, the phosphorus modification of ZSM-5 zeolite generally adopts the impregnation method to introduce phosphorus, which is a complicated process. Summary of the invention
[0004] The invention provides a method for preparing a P-ZSM-5 molecular sieve by using yellow phosphorus slag, and applying the prepared molecular sieve to a methanol to propylene reaction. The yellow phosphorus slag is used as a raw material, and the P-ZSM-5 molecular sieve is prepared by acid leaching, aging, hydrothermal crystallization, calcination, ion exchange and calcination, and the molecular sieve is applied to a methanol to propylene reaction.
[0005] The technical solution of the present invention is as follows:
[0006] A method for preparing a P-ZSM-5 molecular sieve using yellow phosphorus slag comprises the following steps:
[0007] (1) drying the yellow phosphorus slag, treating it in a sample preparation pulverizer, and then passing it through a 200-mesh sieve to obtain yellow phosphorus slag powder;
[0008] (2) mixing yellow phosphorus slag powder and nitric acid in a three-necked flask, heating and stirring in a constant temperature magnetic stirrer, and then washing, filtering, and drying in an oven to obtain acid leaching residue;
[0009] (3) Sodium hydroxide, aluminum source, template and water are placed in a beaker and mixed thoroughly until the solution becomes transparent, then the acid leaching residue is added, and the mixture is stirred and aged at room temperature;
[0010] (4) transferring the aged mixture to a hydrothermal reactor for crystallization in an oven, cooling to room temperature after the reaction is completed, filtering, washing, drying, and calcining the reactants to obtain a Na-type P-ZSM-5 molecular sieve;
[0011] (5) The Na-type P-ZSM-5 molecular sieve is ion exchanged and then calcined to obtain the H-type P-ZSM-5 molecular sieve.
[0012] In step (1), the yellow phosphorus slag is placed in an electric oven and dried at a constant temperature of 80-100° C. for 24 hours.
[0013] In step (2), the mass concentration of nitric acid is 10%, and the mass ratio of yellow phosphorus slag powder to nitric acid is 1:10; the heating and stirring time is 3 hours, and the heating and stirring temperature is 80-100° C.; washing to neutrality, the drying temperature in the oven is 80° C., and the drying time is 24 hours.
[0014] In step (3), the aluminum source is sodium aluminate or aluminum powder, and the template agent is tetraethylammonium hydroxide or tetrapropylammonium hydroxide.
[0015] In step (3), the mixture obtained by mixing sodium hydroxide, aluminum source, template, water and acid leaching residue is SiO2:P:Al2O3:NaOH:H2O:template=1:0.1:(0.0007-0.04):(0.1-0.4):(5-20):(0.06-0.2) in a molar ratio, wherein Al2O3 is all aluminum elements converted into oxides, and SiO2 is all silicon elements converted into oxides.
[0016] In step (3), the beaker is placed on a constant temperature magnetic stirrer for stirring and aging, and the stirring time is 1-3 hours.
[0017] In step (4), the crystallization temperature is 150-180° C. and the crystallization time is 24-48 hours.
[0018] In step (4), the drying temperature is 80°C and the drying time is 12-24 hours; the calcination is performed by heating the temperature in a muffle furnace at 10° / min to 500-600°C and calcining for 6 hours.
[0019] In step (5), the specific method of preparing H-type P-ZSM-5 molecular sieve by ion exchange of Na-type P-ZSM-5 molecular sieve is: mixing Na-type P-ZSM-5 molecular sieve with 0.2-1 mol / L NH4Cl solution at a solid-liquid ratio of g:mL of 1:20, ion exchange at 80°C-100°C for 2-5h, filtering and repeating 3 times.
[0020] In step (5), the calcination is performed by heating the temperature in a muffle furnace at 10° / min to 500-600°C for 5 hours.
[0021] The present invention also provides the use of the P-ZSM-5 molecular sieve prepared by the above method as a catalyst in the methanol to propylene reaction process. After the P-ZSM-5 molecular sieve is treated at 550° C. and 100% water vapor atmosphere for 10 hours and then used in the methanol to propylene reaction, the conversion rate is higher and the catalyst life is longer.
[0022] Compared with the prior art, the present invention has the following advantages:
[0023] The invention adopts yellow phosphorus slag as a raw material instead of chemical reagents, and can prepare a P-ZSM-5 molecular sieve with regular morphology and structure through a simple acid leaching-hydrothermal method; the raw material cost of the molecular sieve preparation is greatly reduced, and an effective yellow phosphorus slag utilization method is provided; the molecular sieve can be used as a catalyst in the reaction of methanol to propylene, has good catalytic performance and high propylene selectivity, and solves the problem of resource waste and environmental pollution caused by solid waste yellow phosphorus slag. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 The XRD pattern of PZ-1 prepared in Example 1;
[0025] Figure 2 This is the SEM image of PZ-1 prepared in Example 1;
[0026] Figure 3 The XRD pattern of PZ-2 prepared in Example 2;
[0027] Figure 4 This is the SEM image of PZ-2 prepared in Example 2;
[0028] Figure 5 XRD patterns of PZ-3, PZ-4 and PZ-5 prepared in Examples 3-5;
[0029] Figure 6SEM images of PZ-3, PZ-4 and PZ-5 prepared in Examples 3-5;
[0030] Figure 7 The curves of methanol conversion, propylene selectivity and ethylene selectivity of P-ZSM-5 in MTP reaction;
[0031] Figure 8 The curves of methanol conversion, propylene selectivity and ethylene selectivity of P-ZSM-5 after hydrothermal treatment in the MTP reaction. DETAILED DESCRIPTION
[0032] In order to further illustrate the present invention, the present invention is described in detail below in conjunction with specific embodiments, but they should not be construed as limiting the protection scope of the present invention.
[0033] Example 1
[0034] A method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag, the specific steps are as follows:
[0035] (1) Take yellow phosphorus slag and place it in an electric oven at 80°C for 24 hours, process it in a sample preparation grinder, and then pass it through a 200-mesh sieve to obtain its powder;
[0036] (2) 20 g of yellow phosphorus slag powder and 200 g of 10% nitric acid were placed in a three-necked flask and stirred at 100° C. for 3 h in a constant temperature magnetic stirrer. The reactants were washed to neutrality, filtered, and dried in an oven at 80° C. for 24 h to obtain acid leaching residue;
[0037] (3) Sodium hydroxide, aluminum source sodium metaaluminate, template agent tetrapropylammonium hydroxide TPAOH and water are placed in a beaker and mixed thoroughly until the solution becomes transparent, and then the acid leaching residue obtained in step (2) is added, and the molar ratio of each item in the mixture is SiO2:P:Al2O3:NaOH:H2O:TPAOH=1:0.1:0.0007:0.36:6:0.12. The mixture is placed in a beaker, which is placed on a constant temperature magnetic stirrer, and stirred and aged at room temperature for 3 hours;
[0038] (4) transferring the aged mixture to a hydrothermal reactor, crystallizing it in an oven at 170° C. for 48 hours, cooling it to room temperature after the reaction is completed, filtering the reactants, washing them to neutrality, drying them at 80° C. for 20 hours, and then calcining them in a muffle furnace at a heating rate of 10° C. / min, a calcination temperature of 550° C., a calcination time of 6 hours, and cooling them at room temperature to obtain a Na-type P-ZSM-5 molecular sieve;
[0039] (5) Weigh 3 g of Na-type P-ZSM-5 molecular sieve powder and place it in a round-bottom flask. Add 60 mL of 1 mol / L NH4Cl solution and stir in a 90°C oil bath for 2 h to perform ion exchange. Filter and discard the mother liquor. Add 60 mL of 1 mol / L NH4Cl solution again and perform two more exchanges under the same conditions. The ion exchange product is placed in a muffle furnace and heated to 550°C at a rate of 10° / min and calcined for 5 h. After cooling in the furnace, the H-type P-ZSM-5 molecular sieve is obtained, which is named PZ-1.
[0040] The XRD spectrum of PZ-1 prepared in this example is shown in Figure 1 , proving that its structure is MFI structure, SEM morphology is as follows Figure 2 As shown, the zeolite crystals are uniform in size and well-crystallized, and the typical coffin-shaped structure of P-ZSM-5 crystals can be seen.
[0041] Example 2
[0042] A method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag, the specific steps are as follows:
[0043] P-ZSM-5 molecular sieve was prepared according to the method of Example 1, except that the molar ratio of the template agent tetraethylammonium hydroxide (TEAOH) to SiO2 was 0.15. The remaining steps were the same as in Example 1, and the prepared molecular sieve was named PZ-2.
[0044] The XRD spectrum of the molecular sieve in this example is shown in Figure 3 , proving that its structure is MFI structure, SEM morphology is as follows Figure 4 As shown, the zeolite crystals are uniform in size and well-crystallized, and the typical coffin-shaped structure of P-ZSM-5 crystals can be seen.
[0045] Example 3
[0046] A method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag, the specific steps are as follows:
[0047] P-ZSM-5 molecular sieve was prepared according to the method of Example 1, except that the feed amount was such that SiO2:Al2O3=1:0.04 in the mixture. The remaining steps were the same as in Example 1. The prepared molecular sieve was named PZ-3.
[0048] Example 4
[0049] A method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag, the specific steps are as follows:
[0050] P-ZSM-5 molecular sieve was prepared according to the method of Example 1, except that the feed amount was such that SiO2:Al2O3 in the mixture was 1:0.03. The remaining steps were the same as in Example 1. The prepared molecular sieve was named PZ-4.
[0051] Example 5
[0052] A method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag, the specific steps are as follows:
[0053] P-ZSM-5 molecular sieve was prepared according to the method of Example 1, except that the feed amount was such that SiO2:Al2O3 in the mixture was 1:0.02. The remaining steps were the same as in Example 1. The prepared molecular sieve was named PZ-5.
[0054] The XRD spectrum of the molecular sieve prepared in Example 3-5 is shown in Figure 5 , proving that its structure is MFI structure, SEM morphology is as follows Figure 6 As shown, the zeolite crystals are uniform in size and well-crystallized, and the typical coffin-shaped structure of P-ZSM-5 crystals can be seen.
[0055] Example 6
[0056] A method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag, the specific steps are as follows:
[0057] (1) Take yellow phosphorus slag and place it in an electric oven at 90°C for 24 hours, process it in a sample preparation grinder, and then pass it through a 200-mesh sieve to obtain its powder;
[0058] (2) 20 g of yellow phosphorus slag powder and 200 g of 10% nitric acid are placed in a three-necked flask and stirred at 80° C. for 3 h in a constant temperature magnetic stirrer. The obtained mixture is washed to neutrality, filtered, and dried in an oven at 80° C. for 24 h to obtain acid leaching residue;
[0059] (3) Sodium hydroxide, aluminum source sodium metaaluminate, template agent tetrapropylammonium hydroxide (TPAOH) and water are placed in a beaker and mixed thoroughly until the solution becomes transparent, and then the acid leaching residue obtained in step (2) is added. The mixture is stirred and aged at room temperature for 1 hour. The molar ratio of each item in the mixture is SiO2:P:Al2O3:NaOH:H2O:TPAOH=1:0.1:0.001:0.1:5:0.06;
[0060] (4) transferring the aged mixture to a hydrothermal reactor, crystallizing it in an oven at 180°C for 24 hours, cooling it to room temperature after the reaction is completed, filtering the reactants, washing them to neutrality, drying them at 80°C for 24 hours, and then calcining them in a muffle furnace at a heating rate of 10°C / min, a calcination temperature of 500°C, a calcination time of 6 hours, and cooling them at room temperature to obtain a Na-type P-ZSM-5 molecular sieve;
[0061] (5) Weigh 3 g of Na-type P-ZSM-5 molecular sieve raw powder and place it in a round-bottom flask, add 60 mL of 0.5 mol / L NH4Cl solution, stir in an 80°C oil bath for 5 h to perform ion exchange, filter, discard the mother liquor, add 60 mL of 0.5 mol / L NH4Cl solution again, and perform two more exchanges under the same conditions. The ion exchange product is placed in a muffle furnace, and the temperature is raised to 500°C at a rate of 10° / min and calcined for 5 h. After cooling in the furnace, the H-type P-ZSM-5 molecular sieve is obtained.
[0062] Example 7
[0063] A method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag, the specific steps are as follows:
[0064] (1) Take yellow phosphorus slag and place it in an electric oven at 100°C for 24 hours, process it in a sample preparation grinder, and then pass it through a 200-mesh sieve to obtain its powder;
[0065] (2) 20 g of yellow phosphorus slag powder and 200 g of 10% nitric acid are placed in a three-necked flask and stirred at 90° C. for 3 h in a constant temperature magnetic stirrer. The resulting mixture is washed to neutrality, filtered, and dried in an oven at 80° C. for 24 h to obtain acid leaching residue;
[0066] (3) Sodium hydroxide, aluminum source sodium aluminate, template agent tetraethylammonium hydroxide and water are placed in a beaker and mixed thoroughly until the solution becomes transparent, and then the acid leaching residue obtained in step (2) is added, and the mixture is stirred and aged at room temperature for 2 hours, and the molar ratio of each item in the mixture is SiO2:P:Al2O3:NaOH:H2O:TEAOH=1:0.1:0.04:0.4:20:0.2;
[0067] (4) transferring the aged mixture to a hydrothermal reactor, crystallizing it in an oven at 150° C. for 40 h, cooling it to room temperature after the reaction is completed, filtering the reactants, washing them to neutrality, drying them at 80° C. for 12 h, and then calcining them in a muffle furnace at a heating rate of 10° C. / min, a calcination temperature of 600° C., a calcination time of 6 h, and cooling them at room temperature to obtain a Na-type P-ZSM-5 molecular sieve;
[0068] (5) Weigh 3 g of Na-type P-ZSM-5 molecular sieve raw powder and place it in a round-bottom flask, add 60 mL of 0.2 mol / L NH4Cl solution, stir in a 100°C oil bath for 3 h to perform ion exchange, filter, discard the mother liquor, add 60 mL of 0.2 mol / L NH4Cl solution again, and perform two more exchanges under the same conditions. The ion exchange product is placed in a muffle furnace, and the temperature is raised to 600°C at 10° / min and calcined for 5 h. After cooling in the furnace, the H-type P-ZSM-5 molecular sieve is obtained.
[0069] Example 8
[0070] The PZ-4 prepared in Test Example 4 was used as a catalyst in the methanol to propylene reaction. In a fixed bed reactor, the reaction was carried out at 480°C, 0.1 MPa and a methanol mass space velocity of 6 h -1 The methanol conversion, propylene selectivity and ethylene selectivity are shown in Figure 7 When the catalyst can continue to react for 16 hours, the propylene selectivity reaches 38%, the ethylene selectivity reaches 35%, and the methanol conversion rate is high.
[0071] The PZ-4 prepared in Example 4 was subjected to hydrothermal aging treatment at 550°C in a 100% steam atmosphere for 10 h and then used as a catalyst in a methanol to propylene reaction. In a fixed bed reactor, the reaction was carried out at 480°C, 0.1 MPa and a methanol mass space velocity of 6 h -1 The methanol conversion, propylene selectivity and ethylene selectivity are shown in Figure 8 By comparison, it can be seen that the catalyst life doubled after hydrothermal aging treatment and can last for 32 hours, and the propylene selectivity was greatly improved to 54%.
[0072] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.
Claims
1. A method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag, characterized in that: The following steps are involved: (1) drying and powdering yellow phosphorus slag and then passing through a 200-mesh sieve to obtain yellow phosphorus slag powder; (2) mixing yellow phosphorus slag powder with nitric acid, heating and stirring, washing, filtering, and drying to obtain acid leaching residue; (3) Sodium hydroxide, aluminum source, template and water are fully mixed until the solution becomes transparent, then acid leaching residue is added, and the mixture is stirred and aged at room temperature; (4) crystallizing the aged mixture, cooling it to room temperature after the reaction is completed, filtering, washing, drying, and calcining the reactant to obtain a Na-type P-ZSM-5 molecular sieve; (5) The Na-type P-ZSM-5 molecular sieve is ion exchanged and then calcined to obtain the H-type P-ZSM-5 molecular sieve.
2. The method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag according to claim 1, characterized in that: In step (1), the drying temperature is 80-100° C. and the drying time is 24 hours.
3. The method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag according to claim 1, characterized in that: In step (2), the mass concentration of nitric acid is 10%, and the mass ratio of yellow phosphorus slag powder to nitric acid is 1:10; the heating and stirring time is 3 hours, and the heating and stirring temperature is 80-100° C.; washing to neutrality, the drying temperature is 80° C., and the drying time is 24 hours.
4. The method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag according to claim 1, characterized in that: In step (3), the aluminum source is sodium aluminate or aluminum powder, and the template is tetraethylammonium hydroxide or tetrapropylammonium hydroxide.
5. The method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag according to claim 1, characterized in that: In step (3), sodium hydroxide, aluminum source, template and water are added to the mixture obtained by mixing the acid leaching residue, and the molar ratio of SiO2:P:Al2O3:NaOH:H2O:template=1:0.1:(0.0007-0.04):(0.1-0.4):(5-20):(0.06-0.2) is calculated.
6. The method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag according to claim 1, characterized in that: In step (3), the stirring aging time is 1-3h.
7. The method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag according to claim 1, characterized in that: In step (4), the crystallization temperature is 150-180°C and the crystallization time is 24-48h; the drying temperature is 80°C and the drying time is 12-24h; and the calcination is carried out by heating the material to 500-600°C at a heating rate of 10° / min and calcining the material for 6h.
8. The method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag according to claim 1, characterized in that: In step (5), the specific method of preparing H-type P-ZSM-5 molecular sieve by ion exchange of Na-type P-ZSM-5 molecular sieve is: mixing Na-type P-ZSM-5 molecular sieve with 0.2-1 mol / L NH4Cl solution at a solid-liquid ratio of g:mL of 1:20, ion exchange at 80°C-100°C for 2-5h, filtering and repeating 3 times.
9. The method for preparing P-ZSM-5 molecular sieve using yellow phosphorus slag according to claim 1, characterized in that: In step (5), the calcination is carried out by heating the temperature to 500-600°C at a heating rate of 10° / min and calcining for 5 hours.
10. Use of the P-ZSM-5 molecular sieve prepared by the method of claim 1 as a catalyst in a methanol to propylene reaction process.