NaP molecular sieve catalyst prepared from Fischer-Tropsch synthesis waste, method and application

Abstract

This invention discloses a NaP molecular sieve catalyst prepared using Fischer-Tropsch synthesis waste residue, its method, and its application, belonging to the field of catalytic materials and polymer degradation technology. It includes a NaP-type molecular sieve support on which active metal components copper and nickel are loaded. The loading amounts of copper and nickel on the support are 12–76 wt% and 11–70 wt%, respectively. The silica-alumina ratio of the NaP-type molecular sieve support is 6.5–7.5, the sodium-silicon ratio is 1.3–2.0, the water-silicon ratio is 75–90, and the water-sodium ratio is 50. The NaP molecular sieve catalyst can be applied to the depolymerization of lignin. The NaP molecular sieve catalyst combines the catalytic advantages of two metals, effectively improving the liquefaction rate of lignin.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials and polymer degradation technology, and relates to NaP molecular sieve catalysts prepared using Fischer-Tropsch synthesis waste residue, methods, and applications. Background Technology

[0002] Fischer-Tropsch synthesis-based indirect coal liquefaction technology is one of the effective methods to alleviate oil resource shortages and promote the clean and efficient utilization of coal resources. The Fischer-Tropsch synthesis process generates waste filter cake residue, known as waste wax, which contains paraffin wax, deactivated catalysts, deactivated clay, and other solid waste. Currently, there is no good method for utilizing the silicon, aluminum, and iron-containing waste residue from Fischer-Tropsch synthesis as solid waste, resulting not only in resource waste but also environmental pollution. If the waste residue in the waste wax could be recycled and utilized, it would not only bring considerable economic benefits but also reduce the environmental impact of hazardous waste.

[0003] NaP-type molecular sieves are widely used in industrial production. Due to their unique alkali zeolite framework structure, they can effectively adsorb heavy metal ions and are widely applied in hard water treatment, industrial wastewater purification, and the production of environmental cleaning agents. The main components in the preparation of NaP-type molecular sieves are silicon and aluminum. Currently, commonly used raw materials both domestically and internationally include industrial wastes with high Si and Al content, such as metakaolin, fly ash, and coal gangue.

[0004] Lignin, as the second most abundant biomass resource, can be used to produce liquid fuels and high-value-added chemical products, with broad prospects for industrial applications. However, lignin's complex spatial structure makes it difficult to depolymerize and utilize directly, which is currently a technological bottleneck in lignin utilization. Therefore, catalytically depolymerizing renewable lignin to prepare small-molecule compounds is of great significance.

[0005] Although numerous methods for lignin depolymerization and various catalysts have emerged, efficiently, controllably, and cost-effectively depolymerizing lignin remains a significant challenge. The key to effectively solving this problem lies in the design and preparation of catalysts. Therefore, developing catalysts with strong catalytic activity, high selectivity, good stability, and low cost has become a hot topic in lignin catalytic depolymerization. For example, Zou et al. prepared Cu-Ni@C non-noble metal catalysts using Ni-MOF as a support. Under mild conditions (120°C), the BPE conversion rate with isopropanol as the hydrogen source was as high as 89.6%. At a reaction temperature of 260°C, the depolymerization rate of corn cob lignin was 81.12%, and the phenol monomer yield reached 11.46 wt%. Chinese invention patent CN 114471666 A discloses a chromium-zinc modified molecular sieve supported bimetallic catalyst and its preparation and application in lignin depolymerization. This invention uses chromium-zinc modified all-silica molecular sieve MCM-41 as a support, and loads active components copper metal and other transition metals to obtain a chromium-zinc modified molecular sieve supported bimetallic catalyst. The preparation process of this invention is simple. At a temperature of 280°C, with water as the hydrogen source, the liquefaction rate of lignin is 82.47%. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and proposes a NaP molecular sieve catalyst prepared using Fischer-Tropsch synthesis waste residue, a method thereof, and its application, which further improves the lignin liquefaction rate.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] The NaP molecular sieve catalyst prepared using Fischer-Tropsch synthesis waste includes a NaP-type molecular sieve support on which active metal components copper and nickel are loaded. The loading amounts of copper and nickel on the support are 12–76 wt% and 11–70 wt%, respectively. The NaP-type molecular sieve support has a silica-alumina ratio of 6.5–7.5, a sodium-silicon ratio of 1.3–2.0, a water-silicon ratio of 75–90, and a water-sodium ratio of 50.

[0009] Preferably, the raw materials for preparing the NaP-type molecular sieve support include Fischer-Tropsch synthesis waste residue, which consists of 70%-80% by mass of silicon dioxide, 10%-15% of aluminum oxide and 2%-8% of iron oxide.

[0010] Preferably, the ratio of copper to nickel atoms is between 1 and 6.

[0011] Preferably, the NaP-type molecular sieve support has a silicon-to-aluminum ratio of 7.5, a sodium-to-silicon ratio of 1.5, a water-to-silicon ratio of 90, and a water-to-sodium ratio of 50.

[0012] The method for preparing the NaP molecular sieve catalyst using Fischer-Tropsch synthesis waste includes the following steps:

[0013] 1) Remove organic matter from the surface of the Fischer-Tropsch synthesis waste residue to obtain dried material N;

[0014] 2) Preparation of NaP molecular sieve: Add alkali to material N and perform high-temperature alkali melting, then add aluminum source for crystallization, and obtain NaP type molecular sieve after washing and drying;

[0015] 3) The NaP-type molecular sieve was impregnated and loaded in a mixed solution of Cu(NO3)2·3H2O and Ni(NO3)2·6H2O;

[0016] 4) The loaded NaP molecular sieve is dried, ground, and then calcined to obtain the NaP molecular sieve catalyst.

[0017] Preferably, in step 1), the crushed Fischer-Tropsch synthesis waste wax is sieved to below 40 mesh and then placed in a muffle furnace for high-temperature calcination to remove surface organic matter.

[0018] Preferably, the roasting temperature in step 4) is 200-600℃, the time is 2-6h, and the heating rate is 5℃ / min.

[0019] Preferably, the aluminum source is NaAlO2, the crystallization temperature is 90℃-120℃, and the crystallization time is 24h.

[0020] The application of the NaP molecular sieve catalyst prepared using Fischer-Tropsch synthesis waste in the depolymerization of lignin.

[0021] The process involves mixing alkali-degraded lignin substrate, reaction solvent, and NaP molecular sieve catalyst, and then catalytically depolymerizing the alkali-degraded lignin under high temperature, high pressure, and supercritical conditions to obtain the depolymerization product.

[0022] Preferably, the reaction solvent is ethanol; the mass ratio of the dealkalized lignin substrate to the volume of the reaction solvent is 1 g: 200 mL; and the mass ratio of the dealkalized lignin substrate to the NaP molecular sieve catalyst is 2:1.

[0023] Preferably, the catalytic depolymerization temperature is 260–340℃, the time is 0.5–3h, and the rotation speed is 300 rpm / min.

[0024] The beneficial effects of this invention compared to the prior art are as follows:

[0025] 1. The NaP molecular sieve catalyst prepared in this invention combines the catalytic advantages of two metals. Nickel exhibits strong catalytic hydrogenation activity, effectively breaking CO and C-C bonds in lignin. The addition of copper, with its strong hydrogen activation ability, improves the agglomeration of nickel, enhances its dispersibility, increases active sites, and improves the reactivity of the lignin depolymerization catalytic system. Therefore, it boasts the advantage of high lignin conversion rate in catalytic depolymerization. Under the action of a copper- and nickel-supported porous sieve catalyst, lignin is catalytically depolymerized and dealkalized, achieving efficient utilization of lignin.

[0026] 2. The system for preparing NaP molecular sieve catalysts from Fischer-Tropsch synthesis waste using the methods described in this invention exhibits high efficiency in lignin depolymerization, requires no additional hazardous gases for pressurization, has a short reaction time, and achieves a high lignin conversion rate. It can directly use dealkalized lignin as a raw material, which is inexpensive and readily available. Furthermore, it utilizes Fischer-Tropsch synthesis waste in a green manner, aligning with the concept of environmental protection. Moreover, the depolymerization reaction process of this invention does not use toxic or harmful solvents, making the reaction process environmentally friendly.

[0027] 3. The waste material for the NaP-type molecular sieve catalyst prepared by this invention is a Fischer-Tropsch synthesis waste residue, whose main components are silicon dioxide, aluminum oxide, and ferric oxide, etc., which can provide silicon and aluminum sources for the preparation of molecular sieves. This invention effectively utilizes the Fischer-Tropsch synthesis waste residue in a green and efficient manner, reduces the cost of lignin liquefaction catalysts, and improves the lignin liquefaction rate. It achieves a win-win situation by effectively utilizing the waste residue while simultaneously preparing low-cost lignin depolymerization catalysts. Attached Figure Description

[0028] Figure 1 The XRD patterns of various stages in Embodiment 5 and Comparative Example 9 of the present invention are shown below.

[0029] In the figure, the blue line represents the untreated Fischer-Tropsch synthesis waste wax in Example 5; the black line represents the metal-free NaP molecular sieve catalyst prepared in Comparative Example 9; the red line represents the NaP molecular sieve catalyst with a copper-nickel ratio of 6 finally prepared in step 4 of Example 5; the green line represents the NaP molecular sieve catalyst impregnated with copper-nickel metal (ratio of 6) and not calcined after step 3 of Example 5; and the purple line represents the NaP molecular sieve prepared in step 2 of Example 5.

[0030] Figure 2 This is a SEM image of the initial raw material, Fischer-Tropsch synthesis waste wax, from Example 1 of the present invention.

[0031] Figure 3 This is a SEM image of the NaP molecular sieve prepared from the Fischer-Tropsch synthesis waste residue in Example 5 of the present invention.

[0032] Figure 4SEM image of the NaP molecular sieve catalyst prepared from Fischer-Tropsch synthesis waste in Example 5 of this invention;

[0033] Figure 5 yes Figure 4 Enlarged image;

[0034] Figure 6 This is the total ion chromatogram of the depolymerized liquid product in Example 5 of the present invention. Detailed Implementation

[0035] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0036] In the following examples, the total ion chromatograms of each compound monomer were obtained by gas chromatography-mass spectrometry (GC-MS). The detected components were analyzed using the MS database NIST11 and retention times.

[0037] The formula for calculating the lignin conversion rate in the catalytic product in the following examples is: w = (mass of lignin raw material added before reaction - mass of dried filter residue after reaction) / mass of initial added lignin × 100%.

[0038] Example 1

[0039] (1) Treatment of Fischer-Tropsch synthesis waste wax: The Fischer-Tropsch synthesis waste wax is crushed to obtain material M, which is then sieved to below 40 mesh and placed in a muffle furnace for high-temperature calcination to remove surface organic matter and obtain dried material N; wherein, the calcination temperature is 350℃ and the time is 1h.

[0040] (2) Preparation of NaP type molecular sieve porous support: The silicon-aluminum ratio was determined to be 5.5, the sodium-silicon ratio to be 1.3, the water-sodium ratio to be 50, and the water-silicon ratio to be 65. 1.3333g of sodium hydroxide and 1.0932g of material N were added and mixed. The mixture was placed in a porcelain boat and placed in a muffle furnace for high-temperature alkaline melting for 1 hour. The temperature of the muffle furnace was 700℃.

[0041] Add 0.1735g of NaAlO2 as an aluminum source, add water and mix evenly, shake at 25℃ for 1h, then transfer to a high-pressure reactor and place in an oven for crystallization at 120℃ for 24h.

[0042] After cooling to room temperature, the sample was removed from the reactor, washed, filtered until the pH reached 7, and dried in an oven at 80°C to obtain a NaP-type molecular sieve porous support.

[0043] (3) Loading: 0.06355g of Cu(NO3)2·3H2O and 0.3521g of Ni(NO3)2·6H2O were added for impregnation and loading, and then dried; the atomic ratio of Cu to Ni was 1:6; the loading amounts of copper and nickel on the support were 13.10wt% and 70.42%, respectively.

[0044] (4) Grind the dried product and calcine it in a tube furnace to obtain a bimetallic supported catalyst; the calcine is carried out in air at a temperature of 500°C for 5 hours and a heating rate of 5°C / min.

[0045] (5) Lignin depolymerization: Weigh the dealkalized lignin substrate, ethanol and NaP molecular sieve catalyst and mix them. Under high temperature and high pressure supercritical conditions, the dealkalized lignin is catalytically depolymerized to obtain the depolymerization product.

[0046] The mass ratio of the dealkalized lignin substrate to the volume of ethanol was 1 g: 200 mL; the mass ratio of the dealkalized lignin substrate to the NaP molecular sieve catalyst was 2:1. The catalytic depolymerization was performed at a temperature of 260 °C for 0.5 h at a rotation speed of 300 rpm / min. The critical pressure at this critical temperature reached 6.78 MPa.

[0047] The lignin liquefaction rate in Example 1 was determined to be 63.06%.

[0048] Example 2

[0049] (1) Treatment of Fischer-Tropsch synthesis waste wax: The Fischer-Tropsch synthesis waste wax is crushed to obtain material M, which is then sieved to below 40 mesh and placed in a muffle furnace for high-temperature calcination to remove surface organic matter and obtain dried material N; wherein, the calcination temperature is 350℃ and the time is 1h.

[0050] (2) Preparation of NaP type molecular sieve porous support: The silicon-aluminum ratio was determined to be 6, the sodium-silicon ratio to be 1.8, the water-sodium ratio to be 50, and the water-silicon ratio to be 90. 1.3333g of sodium hydroxide and 0.7895g of material N were added and mixed. The mixture was placed in a porcelain boat and placed in a muffle furnace for high-temperature alkaline melting for 1 hour. The temperature of the muffle furnace was 700℃.

[0051] 0.1023 g of NaAlO2 was added as an aluminum source, water was added and mixed evenly, and the mixture was shaken at 25°C for 1 h. Then it was transferred to a high-pressure reactor and placed in an oven for crystallization. After cooling to room temperature, it was taken out of the reactor, washed and filtered until the pH was 7. It was then dried in an oven at 80°C to obtain a NaP-type molecular sieve porous support.

[0052] (3) Loading: 0.1271g of Cu(NO3)2·3H2O and 0.3521g of Ni(NO3)2·6H2O were added for impregnation and loading, and then dried; the atomic ratio of Cu to Ni was 1:3; the loading amounts of copper and nickel on the support were 25.42wt% and 70.42%, respectively.

[0053] (4) Grind the dried product and calcine it in a tube furnace to obtain a bimetallic supported catalyst; the calcine temperature is 300℃, the time is 6h, and the heating rate is 5℃ / min.

[0054] (5) Lignin depolymerization: Weigh the dealkalized lignin substrate, ethanol and NaP molecular sieve catalyst and mix them. Under high temperature and high pressure supercritical conditions, the dealkalized lignin is catalytically depolymerized to obtain the depolymerization product.

[0055] The mass ratio of the dealkalized lignin substrate to the volume of ethanol was 1 g: 200 mL; the mass ratio of the dealkalized lignin substrate to the NaP molecular sieve catalyst was 2:1. The catalytic depolymerization was performed at a temperature of 280 °C for 1 h at a rotation speed of 300 rpm / min. The critical pressure at this critical temperature reached 8.53 MPa.

[0056] The lignin liquefaction rate in Example 2 was determined to be 65.94%.

[0057] Example 3

[0058] (1) Treatment of Fischer-Tropsch synthesis waste wax: The Fischer-Tropsch synthesis waste wax is crushed to obtain material M, which is then sieved to below 40 mesh and placed in a muffle furnace for high-temperature calcination to remove surface organic matter and obtain dried material N; wherein, the calcination temperature is 350℃ and the time is 1h.

[0059] (2) Preparation of NaP type molecular sieve porous support: The silicon-aluminum ratio was determined to be 6.5, the sodium-silicon ratio to be 1.5, the water-sodium ratio to be 50, and the water-silicon ratio to be 90. 1.3333g of sodium hydroxide and 1.8948g of material N were added and mixed. The mixture was placed in a porcelain boat and placed in a muffle furnace for high-temperature alkaline melting for 1 hour. The temperature of the muffle furnace was 700℃.

[0060] Add 0.08283g of NaAlO2 as an aluminum source, add water and mix evenly, shake at 25℃ for 1h, then transfer to a high-pressure reactor and place in an oven for crystallization at 100℃ for 24h.

[0061] After cooling to room temperature, the sample was removed from the reactor, washed, filtered until the pH reached 7, and dried in an oven at 80°C to obtain a NaP-type molecular sieve porous support.

[0062] (3) Loading: 0.1907 g of Cu(NO3)2·3H2O and 0.1761 g of Ni(NO3)2·6H2O were added for impregnation and loading, and then dried; the atomic ratio of Cu to Ni was 1:1; the loading amounts of copper and nickel on the support were 38.14 wt% and 35.22%, respectively.

[0063] (4) Grind the dried product and calcine it in a tube furnace to obtain a bimetallic supported catalyst; the calcine temperature is 550℃, the time is 6h, and the heating rate is 5℃ / min.

[0064] (5) Lignin depolymerization: Weigh the dealkalized lignin substrate, ethanol and NaP molecular sieve catalyst and mix them. Under high temperature and high pressure supercritical conditions, the dealkalized lignin is catalytically depolymerized to obtain the depolymerization product.

[0065] The mass ratio of the dealkalized lignin substrate to the volume of ethanol was 1 g: 200 mL; the mass ratio of the dealkalized lignin substrate to the NaP molecular sieve catalyst was 2:1. The catalytic depolymerization was performed at a temperature of 300 °C for 1.5 h at a rotation speed of 300 rpm / min. The critical pressure at this critical temperature reached 11.53 MPa.

[0066] The lignin liquefaction rate in Example 3 was determined to be 81.45%.

[0067] Example 4

[0068] (1) Treatment of Fischer-Tropsch synthesis waste wax: The Fischer-Tropsch synthesis waste wax is crushed to obtain material M, which is then sieved to below 40 mesh and placed in a muffle furnace for high-temperature calcination to remove surface organic matter and obtain dried material N; wherein, the calcination temperature is 350℃ and the time is 1h.

[0069] (2) Prepare NaP type molecular sieve porous support; determine the silicon-aluminum ratio as 7.0, the sodium-silicon ratio as 1.5, the water-sodium ratio as 50, and the water-silicon ratio as 90. Add 1.3333g of sodium hydroxide and 1.8948g of material N, mix them, place them in a porcelain boat and put them in a muffle furnace for high-temperature alkali melting for 1 hour. The temperature of the muffle furnace is 700℃.

[0070] 0.06615 g NaAlO2 was added as an aluminum source, and water was added to mix evenly. The mixture was shaken at 25°C for 1 h, and then transferred to a high-pressure reactor and placed in an oven for crystallization at 90°C for 24 h. After cooling to room temperature, the mixture was removed from the reactor, washed and filtered until the pH reached 7, and then dried in an oven at 80°C to obtain a NaP-type molecular sieve porous support.

[0071] (3) Loading: 0.2542g of Cu(NO3)2·3H2O and 0.1174g of Ni(NO3)2·6H2O were added for impregnation and loading, and then dried; the atomic ratio of Cu to Ni was 2:1; the loading amounts of copper and nickel on the support were 50.84wt% and 23.48%, respectively.

[0072] (4) Grind the dried product and calcine it in a tube furnace to obtain a bimetallic supported catalyst; the calcine temperature is 500℃, the time is 5h, and the heating rate is 5℃ / min.

[0073] (5) Lignin depolymerization: Weigh the dealkalized lignin substrate, ethanol and NaP molecular sieve catalyst and mix them. Under high temperature and high pressure supercritical conditions, the dealkalized lignin is catalytically depolymerized to obtain the depolymerization product.

[0074] The mass ratio of the dealkalized lignin substrate to the volume of ethanol was 1 g: 200 mL; the mass ratio of the dealkalized lignin substrate to the NaP molecular sieve catalyst was 2:1. The catalytic depolymerization was performed at 320 °C for 2 h at a rotation speed of 300 rpm / min. The critical pressure at this critical temperature reached 14.56 MPa.

[0075] The lignin liquefaction rate in Example 4 was determined to be 84.74%.

[0076] Example 5

[0077] (1) Treatment of Fischer-Tropsch synthesis waste wax: The Fischer-Tropsch synthesis waste wax is crushed to obtain material M, which is then sieved to below 40 mesh and placed in a muffle furnace for high-temperature calcination to remove surface organic matter and obtain dried material N; wherein, the calcination temperature is 350℃ and the time is 1h.

[0078] (2) Preparation of NaP type molecular sieve porous support: The silicon-aluminum ratio was determined to be 7.5, the sodium-silicon ratio to be 1.5, the water-sodium ratio to be 50, and the water-silicon ratio to be 90. 1.3333g of sodium hydroxide and 0.9474g of material N were added and mixed. The mixture was placed in a porcelain boat and placed in a muffle furnace for high-temperature alkaline melting for 1 hour. The temperature of the muffle furnace was 700℃.

[0079] Add 0.05169g NaAlO2 as an aluminum source, add water and mix evenly, shake at 25℃ for 1h, then transfer to a high-pressure reactor and place in an oven for crystallization at 120℃ for 24h.

[0080] After cooling to room temperature, the sample was removed from the reactor, washed, filtered until the pH reached 7, and dried in an oven at 80°C to obtain a NaP-type molecular sieve porous support.

[0081] (3) Loading: 0.3813g of Cu(NO3)2·3H2O and 0.05869g of Ni(NO3)2·6H2O were added for impregnation and loading, and then dried; the atomic ratio of Cu to Ni was 6:1; the loading amounts of copper and nickel on the support were 76.26wt% and 11.74%, respectively.

[0082] (4) Grind the dried product and calcine it in a tube furnace to obtain a bimetallic supported catalyst; the calcine temperature is 600℃, the time is 6h, and the heating rate is 5℃ / min.

[0083] (5) Lignin depolymerization: Weigh the dealkalized lignin substrate, ethanol and NaP molecular sieve catalyst and mix them. Under high temperature and high pressure supercritical conditions, the dealkalized lignin is catalytically depolymerized to obtain the depolymerization product.

[0084] The mass ratio of the dealkalized lignin substrate to the volume of ethanol was 1 g: 200 mL; the mass ratio of the dealkalized lignin substrate to the NaP molecular sieve catalyst was 2:1. The catalytic depolymerization was performed at a temperature of 340 °C for 3 h at a rotation speed of 300 rpm / min. The critical pressure at this critical temperature reached 15.96 MPa.

[0085] The lignin liquefaction rate in Example 5 was determined to be 93.19%.

[0086] Examples 6 and 7

[0087] The steps and raw materials in Examples 6 and 7 are the same as in Example 5, the only difference being the parameters listed in Table 1 below:

[0088] Table 1

[0089]

[0090] Comparative Examples 8-11

[0091] The steps and raw materials of Comparative Examples 8-11 are the same as those of Example 5, except for the change of catalyst, as shown in Table 2.

[0092] Table 2

[0093]

[0094] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the present invention, and all of these should be considered to fall within the scope of patent protection determined by the submitted claims.

Claims

1. An application of a NaP molecular sieve catalyst for depolymerizing lignin, characterized in that, The NaP molecular sieve catalyst comprises a NaP-type molecular sieve support on which active metal components copper and nickel are loaded. The loading amounts of copper and nickel on the support are 76.26 wt% and 11.74%, respectively. The NaP-type molecular sieve support has a silicon-to-aluminum ratio of 7.5, a sodium-to-silicon ratio of 1.5, a water-to-silicon ratio of 90, and a water-to-sodium ratio of 50. The atomic ratio of Cu to Ni is 6:

1. The raw materials for preparing the NaP-type molecular sieve support include Fischer-Tropsch synthesis waste residue, which comprises 70%-80% by mass of silicon dioxide, 10%-15% by mass of aluminum oxide, and 2%-8% by mass of iron oxide.

2. The application of the NaP molecular sieve catalyst according to claim 1 for depolymerizing lignin, characterized in that, The preparation method of the NaP molecular sieve catalyst includes the following steps: 1) Remove organic matter from the surface of the Fischer-Tropsch synthesis waste residue to obtain dried material N; 2) Preparation of NaP molecular sieve: Add alkali to material N and perform high-temperature alkali melting, then add aluminum source for crystallization, and obtain NaP type molecular sieve after washing and drying; 3) The NaP-type molecular sieve was impregnated and loaded in a mixed solution of Cu(NO3)2·3H2O and Ni(NO3)2·6H2O; 4) The loaded NaP molecular sieve is dried, ground, and then calcined to obtain the NaP molecular sieve catalyst.

3. The application of the NaP molecular sieve catalyst according to claim 2 for depolymerizing lignin, characterized in that, In step 1), the crushed Fischer-Tropsch synthesis waste wax is sieved to below 40 mesh and then placed in a muffle furnace for high-temperature calcination to remove surface organic matter.

4. The application of the NaP molecular sieve catalyst according to claim 2 for depolymerizing lignin, characterized in that, Step 4) The roasting temperature is 200-600℃, the time is 2-6h, and the heating rate is 5℃ / min.

5. The application of the NaP molecular sieve catalyst according to claim 2 for depolymerizing lignin, characterized in that, The aluminum source was NaAlO2, the crystallization temperature was 90℃-120℃, and the crystallization time was 24h.

6. The application of the NaP molecular sieve catalyst according to claim 1 for depolymerizing lignin, characterized in that, The process involves mixing alkali-degraded lignin substrate, reaction solvent, and NaP molecular sieve catalyst, and then catalytically depolymerizing the alkali-degraded lignin under high temperature, high pressure, and supercritical conditions to obtain the depolymerization product.

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