Ni-ce array point catalyst, preparation method and photovoltaic module eva oxygenated pyrolysis product catalytic upgrading method

Abstract

This invention discloses a Ni-Ce matrix catalyst and its preparation method, as well as a catalytic upgrading method for aerobic pyrolysis products of EVA photovoltaic modules. The preparation method of the Ni-Ce matrix catalyst includes the following steps: Step 1: Prepare nickel salt solution and cerium salt solution respectively; Step 2: Add nickel salt solution and ammonia solution to cerium salt solution by titration, and mix them during the addition to obtain a mixed solution; Step 3: Dry the mixed solution obtained in Step 2 to obtain a cerium-nickel mixture solid, place the obtained cerium-nickel mixture solid into a mold for shaping, and then take out the shaped cerium-nickel mixture solid for calcination and reduction under a hydrogen atmosphere to obtain the Ni-Ce matrix catalyst. The prepared Ni-Ce matrix catalyst catalyzes the directional preparation of aliphatic hydrocarbons from the aerobic pyrolysis products of waste crystalline silicon photovoltaic module EVA.

Description

Technical Field

[0001] This invention belongs to the field of catalysts and high-value recycling of waste crystalline silicon photovoltaic modules, and particularly relates to a Ni-Ce matrix catalyst and its preparation method, and a catalytic upgrading method for aerobic pyrolysis products of EVA in photovoltaic modules. Background Technology

[0002] Crystalline silicon is the most common and predominant type of photovoltaic (PV) module, consistently accounting for 85%-90% of the composition. It primarily consists of glass, EVA (thermal melt adhesive film), solar cells, and backsheets. EVA, an ethylene-vinyl acetate copolymer, is the most frequently used encapsulation material in PV modules, typically comprising 5.1 wt%. The most critical step in PV module recycling is removing the EVA layer. Aerobic pyrolysis ensures uniform heating, complete pyrolysis, and no residual coke adhering to the EVA. However, aerobic pyrolysis of EVA presents challenges due to its complex composition, high oxygen content, and relatively low quality. Summary of the Invention

[0003] To address the aforementioned technical problems, one objective of this invention is to provide a method for preparing a Ni-Ce matrix catalyst that can catalyze the pyrolysis of EVA volatiles to generate aliphatic hydrocarbons.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: A method for preparing a Ni-Ce matrix catalyst, comprising the following steps:

[0005] Step 1: Prepare nickel salt solution and cerium salt solution separately;

[0006] Step 2: Titrate the nickel salt solution and ammonia solution separately into the cerium salt solution, mixing them thoroughly during the titration to obtain a mixed solution;

[0007] Step 3: The mixed solution obtained in Step 2 is dried to obtain a cerium-nickel mixture solid. The obtained cerium-nickel mixture solid is placed into a mold for shaping. Then, the shaped cerium-nickel mixture solid is taken out and calcined, and reduced in a hydrogen atmosphere to obtain a Ni-Ce array catalyst.

[0008] In step 1 of the above technical solution, both the nickel salt solution and the cerium salt solution are nitrate solutions.

[0009] In step 1 of the above technical solution, the concentration of nickel ions in the nickel salt solution and the concentration of cerium ions in the cerium salt solution are both 0.3-1 mol / L.

[0010] In the above technical solution, the content of cerium ions in the mixed solution obtained in step 2 is 2-5 wt% of the content of nickel ions.

[0011] In step 2 of the above technical solution, the cerium salt solution is added dropwise in an ultrasonic hydrothermal system at a temperature of 40-80°C. In step 2, ammonia is added dropwise until no flocculent matter is produced in the mixed solution.

[0012] In step 3 of the above technical solution, the drying temperature is 60-90℃; the calcination temperature is 800-1000℃, and the calcination time is 1-3h; the reduction temperature is 700-900℃, and the reduction treatment time is 1-2h.

[0013] The second objective of this invention is to provide a Ni-Ce matrix catalyst prepared by the above-described preparation method.

[0014] To achieve the above objectives, the technical solution of the present invention is as follows: a Ni-Ce matrix catalyst, prepared by the preparation method described above.

[0015] The third objective of this invention is to provide a method for catalytic upgrading of EVA pyrolysis products in photovoltaic modules.

[0016] To achieve the above objectives, the technical solution of the present invention is as follows: a method for catalytic upgrading of EVA photovoltaic module aerobic pyrolysis products, wherein waste crystalline silicon photovoltaic modules are crushed to obtain scrap, and the scrap is pyrolyzed under low oxygen concentration to obtain volatiles, and the Ni-Ce matrix catalyst is used to catalyze the volatiles to obtain aliphatic hydrocarbons, wherein the Ni-Ce matrix catalyst is heated by electrical energy to generate Joule heat during catalysis.

[0017] The oxygen concentration described in the above technical solution is 3-6 vol%; the pyrolysis temperature is 400-600℃; and the pyrolysis time is 10-30 min.

[0018] The Ni-Ce matrix catalyst described in the above technical solution has a Joule heating temperature of 500-700℃ and a volatile flow rate of 20-50 mL / min during the catalytic reaction.

[0019] The beneficial effects of this invention are as follows: In this embodiment, the prepared Ni-Ce matrix catalyst can generate Joule heat under the action of electrical energy, and catalyze the aerobic pyrolysis products of waste crystalline silicon photovoltaic module EVA to be directionally prepared into aliphatic hydrocarbons, effectively utilizing waste electricity to realize the treatment and high-value utilization of waste crystalline silicon photovoltaic module EVA. Attached Figure Description

[0020] Figure 1 This is a schematic flowchart of the preparation method of the Ni-Ce matrix catalyst described in the embodiments of the present invention. Detailed Implementation

[0021] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0022] This embodiment provides a method for preparing a Ni-Ce matrix catalyst, comprising the following steps:

[0023] Step 1: Prepare nickel salt solution and cerium salt solution separately;

[0024] Step 2: Titrate the nickel salt solution and ammonia solution separately into the cerium salt solution, mixing them thoroughly during the titration to obtain a mixed solution;

[0025] Step 3: The mixed solution obtained in Step 2 is dried to obtain a cerium-nickel mixture solid. The obtained cerium-nickel mixture solid is placed into a mold for shaping. Then, the shaped cerium-nickel mixture solid is taken out and calcined, and reduced in a hydrogen atmosphere to obtain a Ni-Ce array catalyst.

[0026] In step 1, both the nickel salt solution and the cerium salt solution are nitrate solutions (specifically, the nickel salt solution and the cerium salt solution are solutions formed by dissolving nickel nitrate hexahydrate and cerium nitrate hexahydrate in deionized water, respectively).

[0027] In the above technical solution, the concentration of nickel ions in the nickel salt solution and the concentration of cerium ions in the cerium salt solution are both 0.3-1 mol / L in step 1, and the content of cerium ions in the mixed solution obtained in step 2 is 2-5 wt% of the nickel ion content.

[0028] In step 2 of the above technical solution, the cerium salt solution is added dropwise in an ultrasonic hydrothermal system at a temperature of 40-80°C. In step 2, ammonia is added dropwise until no flocculent matter is produced in the mixed solution.

[0029] In step 3 of the above technical solution, the drying temperature is 60-90℃; the calcination temperature is 800-1000℃, and the calcination time is 1-3h; the reduction temperature is 700-900℃, and the reduction treatment time is 1-2h.

[0030] In addition, this invention also provides a method for catalytic upgrading of EVA photovoltaic module aerobic pyrolysis products. Waste crystalline silicon photovoltaic modules are crushed to obtain fragments, which are then pyrolyzed under low oxygen concentration to obtain volatiles. A Ni-Ce matrix catalyst is used to catalyze the volatiles to obtain aliphatic hydrocarbons. The Ni-Ce matrix catalyst is heated by electrical energy to generate Joule heat during catalysis. The low oxygen concentration is 3-6 vol%. The pyrolysis temperature is 400-600℃, the pyrolysis time is 10-30 min, the post-Joule-heated temperature of the Ni-Ce matrix catalyst is 500-700℃, and the flow rate of the volatiles during the catalytic reaction is 20-50 mL / min.

[0031] Example 1

[0032] This embodiment specifically describes the preparation of a Ni-Ce matrix catalyst, and the specific steps are as follows:

[0033] Step 1: Take nickel nitrate hexahydrate and cerium nitrate hexahydrate, and add them separately to deionized water. Stir to dissolve them and prepare nickel nitrate solution (nickel salt solution) and cerium nitrate solution (cerium salt solution) with a concentration of 0.5 mol / L.

[0034] Step 2: Place the cerium salt solution under ultrasonic and 60℃ hydrothermal conditions, and simultaneously slowly titrate the prepared nickel salt solution (2000mL) into the cerium nitrate solution (30mL), while simultaneously slowly adding ammonia water and stirring until no obvious flocculent matter is produced in the solution, and a mixed solution is obtained;

[0035] Step 3: After evaporating the water in the mixed solution, a cerium-nickel mixture solid is obtained. It is then placed in a mold and dried at 80°C. After being removed, it is calcined at 800°C for 2 hours and then reduced at 700°C for 1 hour under hydrogen conditions to obtain the Ni-Ce matrix catalyst.

[0036] The Ni-Ce matrix catalyst was collected and analyzed. The results showed that Ce accounted for 3.2 wt% of the total catalyst mass in the Ni-Ce matrix catalyst, and Ce atoms were highly dispersed on the surface of Ni clusters.

[0037] Example 2

[0038] This embodiment specifically utilizes the Ni-Ce matrix catalyst prepared in the previous embodiment to catalytically upgrade the aerobic pyrolysis products of EVA in photovoltaic modules. The specific steps are as follows:

[0039] Step S1: Cut the waste crystalline silicon photovoltaic modules into uniform sizes that encompass the entire cell size, and pyrolyze them at 500°C for 20 minutes at a 4 vol% oxygen concentration to obtain volatiles;

[0040] Step S2: Using electrical energy (which can be waste electricity generated by a photovoltaic power station) to add Ni-Ce matrix catalyst and generate Joule heat, so that the catalyst surface temperature is 600℃, the volatiles are passed through the Ni-Ce matrix catalyst at a rate of 30mL / min for catalytic upgrading to obtain aliphatic hydrocarbons.

[0041] The volatiles collected after catalytic upgrading were analyzed by GC and GC-MS, and the results showed that aliphatic hydrocarbons accounted for 87.3 wt% of the volatiles.

[0042] Example 3

[0043] Similar to Example 2, the difference is that in step S1, the pyrolysis conditions are pyrolysis at 450°C for 30 min at a concentration of 5 vol% oxygen to obtain volatiles; in step S2, the catalyst surface temperature is 550°C, and the volatiles are passed through a Ni-Ce catalyst at a rate of 20 mL / min for catalytic upgrading to obtain aliphatic hydrocarbons.

[0044] The volatiles collected after catalytic upgrading were analyzed by GC and GC-MS, and the results showed that aliphatic hydrocarbons accounted for 90.2 wt% of the volatiles.

[0045] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a Ni-Ce array point catalyst, characterized by, The method comprises the following steps: Step 1: respectively preparing a nickel salt solution and a cerium salt solution; Step 2: respectively titrating the nickel salt solution and an ammonia solution into the cerium salt solution, and mixing during the titration to obtain a mixed solution; Step 3: drying the mixed solution obtained in step 2 to obtain a cerium-nickel mixture solid, placing the cerium-nickel mixture solid into a mold for shaping, then taking out the shaped cerium-nickel mixture solid for calcination, and reducing under a hydrogen atmosphere to obtain a Ni-Ce dot catalyst; The nickel salt solution and the cerium salt solution in step 1 are both nitrate solutions; The concentration of nickel ions in the nickel salt solution and the concentration of cerium ions in the cerium salt solution in step 1 are both 0.3-1 mol / L; The content of cerium ions in the mixed solution obtained in step 2 is 2-5 wt% of the content of nickel ions; In step 2, the cerium salt solution is added dropwise in an ultrasonic hydrothermal environment, and the hydrothermal temperature is 40-80℃; in step 2, the ammonia solution is added dropwise into the mixed solution until no flocculation occurs; In step 3, the drying temperature is 60-90℃; the calcination temperature is 800-1000℃, and the calcination time is 1-3h; the reduction temperature is 700-900℃, and the reduction time is 1-2h.

2. A Ni-Ce array catalyst characterized by, The preparation method is as claimed in claim 1.

3. A method for catalytic upgrading of EVA oxygenated pyrolysis products of a photovoltaic module, characterized in that, An old crystalline silicon photovoltaic module is crushed to obtain crushed materials, and the crushed materials are pyrolyzed under a low oxygen concentration to obtain volatile matter, and the volatile matter is catalyzed by the Ni-Ce dot catalyst as claimed in claim 2 to obtain aliphatic hydrocarbons, wherein the Ni-Ce dot catalyst is heated by electric energy to generate Joule heat during catalysis.

4. The photovoltaic module EVA autothermal product catalytic upgrading process of claim 3, wherein, The low oxygen concentration is 3-6 vol%, the pyrolysis temperature is 400-600℃, and the pyrolysis time is 10-30min.

5. The photovoltaic module EVA autothermal product catalytic upgrading process of claim 3, wherein, After the Ni-Ce dot catalyst is heated to generate Joule heat, the temperature is 500-700℃, and the flow rate of the volatile matter during catalysis is 20-50mL / min.

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