Patent Description:
A fuel cell has no pollution to the environment. Electrochemical reaction rather than combustion (gasoline and diesel) or energy storage (storage battery) which is the most typical traditional backup power solution that will release pollutants such as COx, NOx, SOx gas and dust while combustion, is employed in the fuel cell. As mentioned above, the fuel cell only generates water and heat. If hydrogen is generated by renewable energy sources (photovoltaic panels, wind power generation, or the like), the whole cycle is a process that does not produce harmful substances completely. According to Energy Storage International Summit, as a clean energy source with zero emissions in the true sense, the application of hydrogen fuel cells in developed countries is accelerating. The fuel cell has gone from laboratory to industrialization. Compared with a lithium battery, it has the advantage of zero pollution.

However, with the continuous and extensive use of the hydrogen fuel cells, the end of life of some old hydrogen fuel cells is approaching, and there are a large number of high-value components in the hydrogen fuel cells, such as various valves and gas pipelines, valuable metal wastes, precious metal platinum in catalysts, and the like. The availability of these high-value wastes makes recycling significant. At present, the recycling of precious metal platinum in catalysts may be summarized as carbonyl platinum chloride method, molten salt electrolysis method, zone smelting method, ammonium chloride repeated precipitation method, sodium bromate hydrolysis method, oxidized carrier hydrolysis method, and the like. The carbonyl platinum chloride method and the molten salt electrolysis method are limited to large-scale production and application due to complicated technological processes and tedious operations thereof. The sodium bromate hydrolysis method and the oxidized carrier hydrolysis method have a large amount of solution treatment and need a long time to stand and clarify, which takes up space and site, has a long generation period, and cannot be applied to large-scale production. Therefore, the existing recycling processes have the defects of high labor intensity, low production efficiency, inconvenient operation and high energy consumption.

Patent document (<CIT>) discloses a method for recovering catalyst from a membrane electrode, which comprises stripping the matrix material of the membrane electrode, and then recovering the catalyst from the membrane electrode stripped of the matrix material, wherein the method for stripping the matrix material of the membrane electrode comprises contacting the membrane electrode with a solvent, wherein the amount of the solvent and the contact conditions are sufficient to strip the matrix material of the membrane electrode from the membrane electrode, and the solvent is a solvent capable of swelling the matrix material of the membrane electrode. In the method, a membrane electrode is soaked in a solvent which can swell the matrix material of the membrane electrode, namely a proton exchange membrane, which is a polymer material, and can absorb liquid solvent to cause physical swelling; after the matrix material swells, the catalytic layer naturally falls off the surface of the matrix material, so that the matrix material is completely stripped from the membrane electrode. Therefore, the stripping method adopted by the catalyst recovery method is simple in process and suitable for stripping the substrate material of the membrane electrode.

The object of the present invention is to provide a method for recycling a hydrogen fuel cell of a new energy vehicle. According to the method, a platinum element in the hydrogen fuel cell can be efficiently recycled, high-purity Pt can be prepared by combining a chlorination evaporation method with a chemical reduction method, precious metal resources are effectively saved, and the recycling process has the advantages of being easy and convenient to operate and high in production efficiency.

To implement the foregoing object, the present invention employs the following technical solutions.

A method for recycling a hydrogen fuel cell of a new energy vehicle includes the following steps of.

Preferably, in step (<NUM>), the specific treatment process of the hydrogen supply system refers to: further disassembling the hydrogen supply system to obtain a hydrogen ejector, a high-pressure hydrogen sealing valve, a reducing valve, a hydrogen tank, a hydrogen circulating pump, an inverter, a hydrogen concentration sensor, a hydrogen temperature sensor, a hydrogenation control unit, a hydrogen pressure sensor, and a hydrogen pipeline.

Preferably, in the process of discharging in step (<NUM>), sealing performances of the high-pressure hydrogen sealing valve, the reducing valve and the hydrogen tank are checked. If there is no air leakage, the high-pressure hydrogen sealing valve, the reducing valve and the hydrogen pipeline are recycled as old parts for repeated utilization. If the hydrogen tank has good sealing performance and is within a service life thereof, the hydrogen tank is recycled for repeated utilization. If the sealing performances of the high-pressure hydrogen sealing valve, the pressure reducing valve, the hydrogen tank and the hydrogen pipeline are not good, the high-pressure hydrogen sealing valve, the pressure reducing valve, the hydrogen tank and the hydrogen pipeline will be directly recycled as waste metal materials. If the hydrogen ejector, the hydrogen circulating pump and the inverter operate normally in the discharging process in step (<NUM>), the hydrogen ejector, the hydrogen circulating pump and the inverter will be recycled for repeated utilization; otherwise, the hydrogen ejector, the hydrogen circulating pump and the inverter will be further disassembled and classified according to the material categories and recycled. The hydrogen concentration sensor, the hydrogen temperature sensor, the hydrogenation control unit and the hydrogen pressure sensor are directly disassembled and classified according to the material categories and recycled.

Preferably, in step (<NUM>), the specific treatment process of the air supply system refers to: further disassembling the air supply system to obtain an air compressor, a muffler, an air valve module, and an air pipeline.

The air compressor and the muffler will be recycled for repeated utilization if the air compressor and the muffler operate normally in the discharging process described in (<NUM>). The air valve module and the air pipeline will be recycled for repeated utilization if there is no air leakage in the discharging process mentioned in (<NUM>), otherwise, the air valve module and the air pipeline will be recycled as waste metal materials.

Preferably, in step (<NUM>), the specific treatment process of the cooling system refers to: further disassembling the cooling system to obtain a water pump, a radiator, a deionization device, and a thermostat (three-way valve).

If the water pump, the radiator, the deionization device, and the thermostat operate normally in the discharging process in step (<NUM>), the water pump, the radiator, the deionization device, and the thermostat will be recycled for repeated utilization; otherwise, the water pump, the radiator, the deionization device, and the thermostat will be further disassembled and classified according to the material categories for recycling.

Preferably, in step (<NUM>), the ashing is carried out at a temperature of <NUM> to <NUM>, and lasts for <NUM> minutes to <NUM> minutes.

The object of the above ashing is to remove carbon, burn out the carbon cloth and generate carbon dioxide, so that the catalyst can be directly separated from the carbon cloth.

In step (<NUM>), the auxiliary agent is one of NaF, CaF<NUM>, KCl, NaCl or CaCl<NUM>.

The above-mentioned auxiliary agent is a solid chlorinating agent, wherein the solid chlorinating agent will be completely or mostly decomposed into a gaseous chlorinating agent such as chlorine gas or HCl during the reaction process and then working, so that the ash will be chlorinated, and enter the ammonium chloride solution with chlorine gas.

Preferably, in step (<NUM>), a weight ratio of the ash to the auxiliary agent is <NUM> : <NUM> to <NUM>.

Preferably, in step (<NUM>), the inert gas is one of nitrogen, helium or argon gas.

In step (<NUM>), the oxidizing gas is one of chlorine gas or bromine gas.

Preferably, in step (<NUM>), the ammonium salt solution is one of ammonium chloride solution or ammonium bromide solution.

Preferably, in step (<NUM>), the inert gas is introduced at a flow rate of <NUM>·min-<NUM> to <NUM>·min-<NUM>, and lasts for <NUM> minutes to <NUM> minutes.

Preferably, in step (<NUM>), the oxidizing gas is introduced at a flow rate of <NUM>·min-<NUM> to <NUM>·min-<NUM>, and lasts for <NUM> minutes to <NUM> minutes.

Preferably, in step (<NUM>), the ammonium salt solution has a concentration of <NUM> mol·L-<NUM> to <NUM> mol·L-<NUM>.

In step (<NUM>), the temperature is raised to <NUM>,<NUM> to <NUM>,<NUM> at a rate of <NUM>·min-<NUM> to <NUM>·min-<NUM>.

Preferably, in step (<NUM>), the reducing agent is one of sodium thiosulfate, sodium borohydride or hydrazine.

More preferably, in step (<NUM>), the reducing agent has a mass concentration of <NUM>% to <NUM>%.

Preferably, in step (<NUM>), a volume ratio of the ammonium chloride solution to the reducing agent is <NUM>: (<NUM> to <NUM>).

Preferably, in step (<NUM>), the further purification process of Pt after preparing Pt in step is as follows: adding a leachate into Pt, heating, washing, filtering, taking a filtrate, adding a reducing agent for reaction, filtering, taking and cleaning a filter residue to obtain pure Pt, wherein a mass ratio of Pt to the leachate is <NUM>: (<NUM> to <NUM>).

More preferably, the leachate is aqua regia, and the aqua regia has a mass concentration of <NUM>% to <NUM>%.

<FIG> is a flowchart of a hydrogen fuel cell recycling process according to Embodiment <NUM> of the present invention.

In order to make the technical solutions of the present invention clearer to those skilled in the art, the following embodiments are listed for explanation. It should be noted that the following embodiments do not limit the scope of protection claimed by the present invention.

Unless otherwise specified, the raw materials, reagents or devices used in the following embodiments can be obtained from conventional commercial sources or by existing known methods.

A method for recycling a hydrogen fuel cell of a new energy vehicle included the following specific steps of:.

A platinum recycling refining process included the following process steps of:.

It can be seen from Tables <NUM> to <NUM> that, in each ton of hydrogen fuel cell, the recycling rate of Pt in Embodiment <NUM> of the present invention is <NUM>% , and the purity of the Pt crude product is <NUM>%; the recycling rate of Cu is <NUM>%, and the purity of the Cu crude product is <NUM>%; the recycling rate of Fe is <NUM>%, and the purity of the Fe crude product is <NUM>%; the recycling rate of Zn is <NUM>%, and the purity of the Zn crude product is <NUM>%; the recycling rate of Al is <NUM>%, and the purity of the Al crude product is <NUM>%; and the recycling rate of plastic is <NUM>%, and the purity of the Pt crude product is <NUM>%. In each ton of hydrogen fuel cell, the recycling rate of Pt in Embodiment <NUM> of the present invention is <NUM>% , and the purity of the Pt crude product is <NUM>%; the recycling rate of Cu is <NUM>%, and the purity of the Cu crude product is <NUM>%; the recycling rate of Fe is <NUM>%, and the purity of the Fe crude product is <NUM>%; the recycling rate of Zn is <NUM>%, and the purity of the Zn crude product is <NUM>%; the recycling rate of Al is <NUM>%, and the purity of the A1 crude product is <NUM>%; and the recycling rate of plastic is <NUM>%, and the purity of the Pt crude product is <NUM>%. In the Comparative Example <NUM>, the recycling rate of Pt is <NUM>%, the recycling rate of Cu is <NUM>%, the recycling rate of Fe is <NUM>%, the recycling rate of Zn is <NUM>%, the recycling rate of Al is <NUM>%, and the recycling rate of plastic is <NUM>%, respectively. The recycling rates of all components are lower than those in Embodiments <NUM> and <NUM>, and the process cost of recycling Pt is much higher than that in Embodiment <NUM>. From this, it can be seen that by using the method for recycling of the present invention, the process for obtaining pure platinum is simple, low in cost, and industrially recoverable.

<FIG> is a flowchart of a waste hydrogen fuel cell recycling process according to Embodiment <NUM> of the present invention. It can be seen from <FIG> that the entire recycling process is simple and efficient. The recycling range includes materials with a specific gravity of more than <NUM>% and can obtain crude products with higher purity. The difficulty in the whole process is the method for recycling platinum. The ashing treatment can directly increase the purity of platinum to more than <NUM>%. After two steps of high temperature chlorination and reduction, the platinum can be purified, and the purity can reach <NUM>%.

Claim 1:
A method for recycling a hydrogen fuel cell, comprising:
(<NUM>) discharging and disassembling a hydrogen fuel cell to obtain a hydrogen supply system, an air supply system, a cooling system and a galvanic pile;
(<NUM>) disassembling the galvanic pile into a catalyst and carbon cloth, and ashing to obtain ash;
(<NUM>) adding an auxiliary agent into the ash, mixing, introducing inert gas, heating, introducing oxidizing gas, and absorbing tail gas by using an ammonium salt solution; and
(<NUM>) adding a reducing agent into the ammonium salt solution absorbing the tail gas in step (<NUM>) to react, filtering, taking and cleaning a filter residue to obtain Pt, wherein in step (<NUM>), the oxidizing gas is one of chlorine gas or bromine gas, wherein in step (<NUM>), the heating is carried out at a rate of <NUM>·min-<NUM> to <NUM>·min-<NUM> and a temperature of <NUM>,<NUM> to <NUM>,<NUM>;
wherein in step (<NUM>), the auxiliary agent is one of NaF, CaF<NUM>, KCl, NaCl or CaCl<NUM>.