Method for repairing through defects in palladium membranes

Abstract

The present application provides a palladium membrane through defect repairing method, which comprises the following steps: first, cleaning the palladium membrane tube, and then drying; second, placing the palladium membrane tube in a sealed cavity, and filling the sealed cavity with nano powder; third, keeping the palladium membrane tube in negative pressure by using a vacuum pump group, and blowing the nano powder in the sealed cavity by using high-speed airflow to complete the defect sealing; fourth, performing reduction atmosphere heat treatment on the palladium membrane tube to complete the palladium membrane tube defect repairing. The method can repair the defects such as palladium membrane micropores and cracks, and improve the purity of hydrogen purified by the palladium membrane.

Description

Technical Field

[0001] This invention relates to the field of hydrogen separation and purification technology, specifically to a method for repairing perforated defects in palladium membranes. Background Technology

[0002] Hydrogen is widely used as a raw material, protective gas, and carrier gas in industries such as methanol synthesis, ammonia production, petrochemicals, metallurgy, and electronics. Hydrogen separation and purification is a crucial step in hydrogen preparation and application. Major hydrogen separation and purification methods include pressure swing adsorption (PSA), catalytic adsorption, metal hydride adsorption, and membrane separation. Palladium separation, a type of membrane separation, works by utilizing the unique permeability of palladium to hydrogen, preventing non-hydrogen gases from passing through, thus achieving hydrogen separation and purification.

[0003] In recent years, porous palladium-supported membranes have been gradually replacing traditional drawn palladium tubes due to their high hydrogen permeation efficiency, low palladium content, and low cost. However, due to surface defects on the support, membrane deposition, and high-temperature heat treatment, the surface of porous palladium-supported membranes is prone to microscopic defects such as micropores and cracks. These defects can cause impurity gases to permeate, affecting the purity of the purified hydrogen. Therefore, it is urgent to address the defects of porous palladium-supported membranes and improve the purity of hydrogen purified by palladium membranes. Summary of the Invention

[0004] The purpose of this invention is to provide a method for repairing through-hole defects in palladium films, so as to solve the problem of low hydrogen purity caused by surface defects in porous carrier-loaded palladium film tubes.

[0005] To address the aforementioned technical problems, this invention provides a method for repairing through-hole defects in a palladium film, comprising:

[0006] The first step is to clean the palladium membrane tube and then dry it;

[0007] The second step is to place the palladium membrane tube in a sealed cavity, and fill the sealed cavity with nanoparticles.

[0008] The third step involves using a vacuum pump unit to maintain negative pressure inside the palladium membrane tube, and using a high-speed airflow to blow away the nanoparticles inside the sealed cavity to complete the defect sealing.

[0009] The fourth step is to perform a reducing atmosphere heat treatment on the palladium film tube to complete the defect repair.

[0010] The palladium film is a tubular membrane tube.

[0011] The palladium film includes, but is not limited to, binary or multi-element alloys such as pure palladium, palladium silver, palladium gold, palladium copper, and palladium silver copper.

[0012] In the first step, the palladium membrane tube is cleaned using ethanol or deionized water.

[0013] In the second step, the nanoparticles are silver oxide, copper oxide, or a combination of both.

[0014] In the second step, the particle size of the nanoparticles is 10-50 nanometers.

[0015] In the third step, the high-speed airflow can be any gas such as air, nitrogen, or argon.

[0016] In the third step, the defect sealing process takes 0.5-5 hours.

[0017] In the fourth step, the heat treatment atmosphere is a reducing gas, which can be pure hydrogen or a mixture of hydrogen and inert gases such as nitrogen, argon or helium, with a hydrogen volume content of 5-100%.

[0018] In the fourth step, the heat treatment temperature is 500-800℃ and the time is 1-12 hours.

[0019] Beneficial effects of the present invention

[0020] This invention employs a novel method for repairing through-hole defects in palladium membranes, which can repair defects such as micropores and cracks in palladium membranes and improve the purity of hydrogen purified by palladium membranes. Attached Figure Description

[0021] Figure 1 Schematic diagram of a palladium film defect repair device. Detailed Implementation

[0022] The following examples illustrate the implementation of the present invention in detail, thereby enabling a full understanding and implementation of how the present invention uses technical means to solve technical problems and achieve technical effects.

[0023] Example 1: Repair of defects in pure palladium film tubes

[0024] The pure palladium membrane tube 1 has a diameter of 12 mm and a length of 300 mm. The membrane tube was cleaned in ethanol and deionized water for 1 hour, and then dried in an oven at 120°C for 12 hours.

[0025] A pure palladium membrane tube is placed in a sealed cavity 2, and the cavity is filled with nano silver oxide powder 3, with an average particle size of 10 nm.

[0026] A vacuum pump unit is used to maintain negative pressure inside the pure palladium membrane tube, and compressed air is used to blow away the nano-silver oxide powder in the sealed cavity. The defect sealing treatment time is 0.5 hours.

[0027] The pure palladium film tube was placed in a tube furnace and heat-treated at 500°C for 4 hours by passing hydrogen gas through it.

[0028] After repair, the hydrogen / nitrogen selectivity of the pure palladium membrane tube increased from 50 to 1000.

[0029] Example 2: Repair of defects in palladium-copper membrane tubes

[0030] The palladium-copper membrane tube has a diameter of 12 mm and a length of 200 mm. The membrane tube is cleaned in ethanol and deionized water for 1 hour, and then dried in an oven at 120°C for 12 hours.

[0031] The palladium-copper membrane tube is placed in a sealed cavity, which is filled with nano-copper oxide powder with an average particle size of 50 nm.

[0032] A vacuum pump unit is used to maintain negative pressure inside the palladium-copper membrane tube, and compressed air is used to blow away the nano-copper oxide powder in the sealed cavity. The defect sealing treatment time is 2 hours.

[0033] The palladium-copper film tube was placed in a tube furnace and heat-treated at 800°C for 12 hours by passing hydrogen gas through it.

[0034] After repair, the hydrogen / nitrogen selectivity of the palladium-copper membrane tube increased from 200 to 2000.

[0035] Example 3: Repair of defects in palladium-silver membrane tubes

[0036] The palladium-silver membrane tubes are 12 mm in diameter and 500 mm in length. The membrane tubes are cleaned in ethanol and deionized water for 1 hour each. After cleaning, the membrane tubes are dried in an oven at 120°C for 12 hours.

[0037] The palladium-silver film tube is placed in a sealed cavity, which is filled with nano-silver oxide powder with an average particle size of 30 nm.

[0038] A vacuum pump unit is used to maintain negative pressure inside the palladium-silver film tube, and compressed air is used to blow away the nano-silver oxide powder in the sealed cavity. The defect sealing treatment time is 5 hours.

[0039] The palladium-silver film tube was placed in a tube furnace and heat-treated at 700°C for 12 hours by passing 50% hydrogen and 50% nitrogen gas through it.

[0040] After repair, the hydrogen / nitrogen selectivity of the palladium-silver membrane tube increased from 500 to 10000.

[0041] All of the foregoing primary implementations of this intellectual property right do not limit other forms of implementation of this new product and / or new method. Those skilled in the art will utilize this important information to modify the foregoing to achieve similar implementations. However, all modifications or alterations based on this new product invention are reserved rights.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for repairing through-hole defects in a palladium film, characterized in that, include: The first step is to clean the palladium membrane tube and then dry it; The second step is to place the palladium membrane tube in a sealed cavity, and fill the sealed cavity with nanoparticles, wherein the nanoparticles are silver oxide, copper oxide or a combination of the two, and the particle size of the nanoparticles is 10-50 nanometers. The third step involves using a vacuum pump unit to maintain negative pressure inside the palladium membrane tube, and using a high-speed airflow to blow away the nanoparticles inside the sealed cavity to complete the defect sealing. The fourth step is to perform a reducing atmosphere heat treatment on the palladium film tube. The reducing atmosphere is pure hydrogen, or a mixture of hydrogen and nitrogen, argon or helium, with the hydrogen volume content in the mixture being greater than 5% and less than 100%, thus completing the repair of defects in the palladium film tube.

2. The palladium film through-hole defect repair method as described in claim 1, characterized in that: The palladium film is a tubular membrane tube.

3. The palladium film through-hole defect repair method as described in claim 1 or 2, characterized in that: The palladium film is pure palladium, palladium silver, palladium gold, palladium copper, or palladium silver copper.

4. The palladium film through-hole defect repair method as described in claim 3, characterized in that: In the first step, the palladium membrane tube is cleaned using ethanol or deionized water.

5. The palladium film through-hole defect repair method as described in claim 4, characterized in that: In the third step, the high-speed airflow uses air, nitrogen, or argon.

6. The palladium film through-hole defect repair method as described in claim 5, characterized in that: In the fourth step, the heat treatment temperature is 500-800℃ and the time is 1-12 hours.

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