CN115123999A

CN115123999A - Method for producing hydrogen by carbon-containing solid

Info

Publication number: CN115123999A
Application number: CN202210847892.3A
Authority: CN
Inventors: 张兆熙; 介翔宇
Original assignee: Wuhan New Carbon Technology Co ltd
Current assignee: Wuhan New Carbon Technology Co ltd
Priority date: 2022-07-19
Filing date: 2022-07-19
Publication date: 2022-09-30

Abstract

The invention belongs to the technical field of energy regeneration, and particularly discloses a method for producing hydrogen by using a carbon-containing solid. The method takes carbon-containing solid as a raw material and comprises two sections of microwave catalytic treatment which are continuously carried out. The efficient and low-carbon hydrogen production method based on the microwave technology can realize high-selectivity, efficient and complete dehydrogenation treatment through the interaction of the catalyst and the microwave, realizes the preparation of high-purity hydrogen from carbon-containing solids, does not generate harmful substances, and has low emission, thereby being a green and low-carbon hydrogen production method.

Description

Method for producing hydrogen by carbon-containing solid

Technical Field

The invention belongs to the field of energy regeneration, and particularly relates to a method for producing hydrogen by using a carbon-containing solid as a raw material.

Background

For future hydrogen energy needs, scientists are constantly looking for hydrogen storage materials that are high in hydrogen and stable. The carbonaceous solid is a solid raw material rich in hydrogen elements, and includes but is not limited to polyolefin plastics, biomass, man-made organic high molecular polymers, biochar, coal, asphalt, coke, paraffin, chemical fibers, tires, medical wastes, household garbage and the like. Selective extraction of hydrogen from carbonaceous solids is a significant challenge.

For example, polypropylene plastic is a plastic garbage which is difficult to degrade and has high rejection rate. At present, the polypropylene plastic treatment method is incineration or landfill, and is a treatment method with high emission and high pollution. Therefore, an innovative process method with environmental protection and high efficiency is an urgent need for processing polypropylene plastics. For the method of producing hydrogen from polypropylene plastics, researchers developed multi-step reaction flows of reforming and thermal cracking-reforming, but both the reforming reaction and the thermal cracking reaction require higher reaction temperature, and most of the generated hydrogen is a synthesizer of hydrogen and carbon monoxide; and generates a large amount of carbon dioxide emissions.

For another example, the treatment of municipal solid waste is mainly focused on harmless and quantitative reduction. The most common domestic garbage treatment method in China is a garbage sanitary landfill method. However, most of the domestic garbage is not classified or harmlessly treated, and toxic substances and other recyclable substances are often mixed in the domestic garbage. The garbage is directly filled without being treated, which not only causes serious secondary pollution, but also causes the waste of partial available resources, and simultaneously increases the filling treatment amount, shortens the service life of a landfill site and causes unnecessary economic loss.

Although the biomass waste has the characteristic of environmental friendliness, the degradation of the biomass waste needs time, the waste of the biomass waste can affect the environment, and the waste of biomass resources is caused. How to utilize the waste resources is an urgent problem to be solved. At present, methods for treating biomass mainly include methods based on chemical conversion, such as gasification methods, pyrolysis reforming methods, and the like. In addition, hydrogen can be produced from biomass waste materials by biological methods such as photolysis water hydrogen production, light fermentation hydrogen production, dark fermentation hydrogen production, light-dark coupling fermentation hydrogen production and the like. However, because of the complexity of biomass structure, the production of hydrogen from biomass as a raw material usually requires a multi-step complicated reaction path, and the intermediate product is subjected to a reforming reaction to produce hydrogen. With the development of microwave pyrolysis technology in recent years, researchers develop technology for treating biomass waste by using the microwave pyrolysis technology, and meanwhile, compared with the traditional pyrolysis technology, the microwave pyrolysis technology has the characteristics of high speed and high hydrogen yield. However, the single microwave pyrolysis treatment can produce a large amount of biomass oil, the distribution of byproducts is wide, the hydrogen yield is greatly reduced, and the utilization is difficult.

Therefore, there is a need to develop a method for producing hydrogen in high yield from carbonaceous solids while avoiding the emission of large amounts of carbon dioxide.

Disclosure of Invention

The present invention aims to overcome the defects of the prior art and provide a method for producing hydrogen from a carbon-containing solid by microwave catalytic dehydrogenation. The method is based on the microwave catalytic dehydrogenation technology, high-purity hydrogen is prepared by decomposing carbon-containing solids, and carbon dioxide emission or other harmful substance emission is not generated in the process, so that a green hydrogen production method and a clean method for treating the carbon-containing solids are provided.

Specifically, the invention provides a method for producing hydrogen by using carbon-containing solids, which takes the carbon-containing solids as raw materials and comprises two stages of microwave catalytic treatment, wherein the method comprises the following steps:

the first stage of microwave catalysis is to perform microwave treatment on the carbon-containing solid raw material under the action of a catalyst A to generate mixed gas;

the second stage of microwave catalysis is to carry out secondary microwave treatment on the mixed gas obtained by the first stage of microwave catalysis under the action of a catalyst B to generate hydrogen-containing gas;

the catalyst A and/or the catalyst B are selected from carbon materials, transition metal materials and transition metal materials taking carbon materials as carriers; the compositions of the catalyst A and the catalyst B are the same or different.

In some embodiments, the carbon material is selected from carbon black, activated carbon, and silicon carbide.

In some embodiments, the transition metal material comprises at least one of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, and tungsten based metal materials.

In some preferred embodiments, the transition metal material is selected from an iron-nickel based metal material, a molybdenum based compound, or a chromium based compound.

Wherein the iron-nickel metal material is selected from one or more of metallic iron, ferrous oxide, ferric oxide, iron carbide, ferroferric oxide, metallic nickel, nickel oxide, iron-nickel alloy and mixed iron-nickel oxide. The molybdenum compound is selected from molybdenum oxide or molybdenum carbide. The chromium-based compound is selected from a chromium oxide compound or chromium carbide.

In some embodiments, the catalyst a is an iron-nickel based metal material or an iron-nickel based metal material with a carbon material as a carrier.

Preferably, the catalyst a is metallic iron, ferric oxide, iron-nickel alloy or metallic iron, ferric oxide or iron-nickel alloy taking carbon material as a carrier.

In some embodiments, the catalyst B is a carbon material, an iron-nickel based metal material, or an iron-nickel based metal material with a carbon material as a support.

Preferably, the catalyst B is a carbon material, metallic iron, iron oxide, iron-nickel alloy or metallic iron, iron oxide or iron-nickel alloy using a carbon material as a carrier.

In some embodiments, the carbonaceous solid comprises at least one of a polyolefin plastic, biomass, synthetic organic high molecular polymer, biochar, coal, pitch, coke, paraffin, chemical fiber, tires, medical waste, household waste.

In some preferred embodiments, the carbonaceous solid is selected from the group consisting of polypropylene plastic, household waste, and biomass.

The household garbage comprises humus, metal articles, plastic articles, paper articles, glass, leather products, cloth articles, ash and wood articles, preferably, the humus content is 5-50 wt%, the metal article content is 0-10 wt%, the plastic article content is 5-50 wt%, the paper article content is 0-30 wt%, the glass content is 0-10 wt%, the leather product content is 0-10 wt%, the cloth article content is 0-10 wt%, the ash and soil residue content is 0-30 wt%, and the wood article content is 0-30 wt%.

The biomass comprises all plants, microorganisms, animals taking the plants and the microorganisms as food and waste produced by the animals. Representative biomasses include crops, crop waste, wood waste and animal manure. Biomass includes, but is not limited to: bioenergy crops, agricultural residues, sludge from paper industry, yard waste, wood and forestry waste. Examples of biomass include, but are not limited to: corn grain, corn cobs, crop residues such as stover, corn husks, corn fiber, grasses, wheat, hay, rice straw, switchgrass, waste paper, bagasse, sorghum stalks, soybean hulls or stalks, components obtained from milling of grains, trees, branches, roots, leaves, wood chips, sawdust, shrubs and bushes, vegetables, fruits, flowers and ruminant animal manure.

Preferably, the biomass feedstock is selected from straw, wood chips, fallen leaves, starch and paper scraps.

In some embodiments, the mass ratio of the carbon material as the carrier to the metal material supported thereon is (0.1 to 10): 1, preferably (0.1-5): 1.

in some embodiments, the mass ratio of carbonaceous solid to catalyst a in the process is (0.5-10): 1.

in some embodiments, the mass ratio of the catalyst A to the catalyst B is (1-5): (1-2).

In some embodiments, the power of the first stage of microwave catalytic treatment is 500-8000W, preferably 1000-6000W;

the power of 500-8000W is adopted in the second stage of microwave catalytic treatment, the preferred power is 1000-6000W, or the temperature of the second stage of microwave catalytic treatment is 600-1000 ℃.

In some embodiments, the frequency of the first stage and/or second stage microwave catalytic treatment is 0.3 to 3GHz, preferably 2.45GHz or 915 MHz.

In some embodiments, the time of the first microwave catalytic treatment is 20-60 min, and/or the time of the second microwave catalytic treatment is 20-60 min.

In some embodiments, the first stage microwave catalytic treatment and the second stage microwave catalytic treatment are performed in an inert environment having an oxygen content of less than 5000ppm at standard atmospheric pressure.

In some embodiments, the method further comprises: after the first stage of microwave catalysis and/or the second stage of microwave catalysis are finished, separating and purifying the product;

preferably, the separation and purification comprises a gas washing and/or pressure swing adsorption treatment.

In some embodiments, the method further comprises: before the first stage of microwave catalysis, the step of purging the mixture of the carbon-containing solid and the catalyst A in the microwave reactor under the condition of nitrogen.

Preferably, the purging is performed for 5 to 20 minutes under the nitrogen condition.

The microwave catalysis adopted by the invention is called as microwave induced catalysis, which is different from the condition that the reaction is accelerated by the microwave thermal effect, the microwave thermal effect usually does not participate in a catalyst, and the microwave catalytic induction is that the microwave plays an induction role through the catalyst or a carrier thereof. The invention realizes the high-efficiency preparation of hydrogen by two-stage microwave catalytic treatment under the action of the catalyst.

The catalyst used in the invention can be prepared by chemical preparation methods known in the art, such as an impregnation method, a precipitation method, a combustion method and the like. For transition metal materials supported on carbon materials or iron-based metal materials supported on carbon materials, the metal may be mixed with the support material in the form of a precursor, including but not limited to nitrates, chlorates, organometallic compounds, and the like. In order to better ensure the effect of microwave absorption of the catalyst, the particle size of the catalyst adopted by the invention is less than 50 μm, and the preferred particle size of the catalyst is 50 nm-10 μm.

The two-stage microwave catalytic treatment of the present invention may be carried out in a microwave reactor with a conventional microwave source (including a magnetron or solid state source). In actual operation, when the first stage of microwave catalytic treatment is started, the catalyst B of the second stage of microwave catalytic treatment is preheated.

In order to realize the characteristic of instantaneous heating and cooling of microwaves and improve the interaction between the microwaves and the catalyst, the furnace body of the reactor for microwave catalytic dehydrogenation (namely the first stage of microwave catalytic treatment) is not provided with wave-absorbing materials. In order to increase the efficiency of the microwave reactor, the microwave reactor for the second stage of microwave catalytic treatment is provided with a silicon carbide material for absorbing waves at the periphery of a furnace body, and the maximum working temperature is 1100 ℃.

The method provided by the invention reduces the temperature and collects the catalyst after the reaction is completed, thereby realizing the cyclic utilization of the catalyst.

Compared with the prior art, the method provided by the invention is based on a microwave catalysis technology, the in-situ heating of the catalyst is realized by the interaction of microwaves and the catalyst, and the active sites on the catalyst are activated. Different from the catalyst, the carbon-containing solid is completely penetrated without heating under the microwave, so that the side reaction of the carbon-containing solid caused by pyrolysis is reduced to the maximum extent, and the catalyst selectively realizes the carbon-hydrogen bond fracture to generate hydrogen. The invention discovers through a great deal of practices that a small amount of micromolecular hydrocarbon mainly comprising methane, ethylene and propylene is also mixed in the hydrogen generated by the primary microwave catalysis; in order to improve the purity of the hydrogen, the invention develops a microwave treatment process of secondary dehydrogenation and purification, adopts a preheating dehydrogenation catalyst, utilizes the characteristic of microwave instantaneous heating to carry out secondary dehydrogenation treatment on the hydrogen-rich gas, effectively improves the yield and the purity of the hydrogen, and prepares the high-purity hydrogen.

Drawings

FIG. 1 is a process flow diagram of a method provided in examples 1-11 of the present invention;

FIG. 2 is a process flow diagram of a method provided in examples 12-21 of the present invention;

FIG. 3 is a process flow diagram of a method provided in examples 22-35 of the present invention.

Detailed Description

The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention.

The method provided by the invention firstly carries out rapid and selective catalytic dehydrogenation treatment on a raw material to be treated, such as polypropylene plastic polymer, through the interaction of microwaves and a catalyst A under the environment of standard atmospheric pressure and no oxygen/little oxygen to generate a mixed gas product containing hydrogen and the like; and (3) after the mixed gas product is subjected to gas washing and collection, introducing the mixed gas product into a catalyst B fixed bed heated by microwave, and performing dehydrogenation and purification treatment on the mixed gas product again to obtain high-purity hydrogen.

When the invention relates to the treatment of household garbage, because of the higher water content of the municipal household garbage, the household garbage is firstly subjected to drying pretreatment and then mixed with a catalyst for catalytic dehydrogenation treatment, and the effect is better. The household garbage is selectively dehydrogenated to produce mixed gas (containing hydrogen, hydrocarbon, carbon oxide and other small gas molecules) of composite hydrogen through the interaction of microwaves and a catalyst. And carrying out secondary catalytic dehydrogenation treatment on the mixed gas to obtain crude hydrogen. And after the crude hydrogen product is subjected to gas washing, purifying by a Pressure Swing Adsorption (PSA) method to obtain high-purity hydrogen. Specifically, the household garbage is dried, crushed and mixed with a catalyst A, and the garbage is subjected to catalytic dehydrogenation reaction under the environment of standard atmospheric pressure and no oxygen/little oxygen; and introducing the product gas obtained by the reaction into a next-stage microwave reaction furnace, and carrying out secondary dehydrogenation treatment on the mixed product through the interaction of microwaves and the catalyst B under the environment of standard atmospheric pressure and no oxygen/little oxygen to remove small-molecular hydrocarbons in the mixed gas so as to obtain a hydrogen-rich gas. And finally, purifying the crude hydrogen product by gas washing and pressure swing adsorption to obtain high-purity hydrogen. The method provided by the invention realizes a low-cost, high-efficiency and low-carbon clean hydrogen production process method from household garbage.

Example 1

In the embodiment, the polypropylene plastic is used as a raw material for hydrogen production, and the process flow is shown in fig. 1, and specifically comprises the following steps:

(1) fully and physically and mechanically mixing 50g of crushed polypropylene plastic with 50g of catalyst A (carbon black supported iron-nickel metal catalyst, wherein the mass ratio of metal iron to metal nickel to carbon is 3:1:1), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 2000W of power and 2.45GHz of frequency to generate a mixed gas product; after the gas washing treatment, collecting a gas product, and sampling and analyzing the gas product;

(2) loading 20g of catalyst B (the same as the catalyst A in the step (1)) into a microwave reactor (2), setting the reaction temperature to be 800 ℃, starting heating up and preheating from room temperature, wherein the heating up rate is 20 ℃/min, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2) for secondary dehydrogenation and purification treatment, carrying out microwave reaction at 800 ℃ for 30 minutes to generate a hydrogen-containing gas product, washing the gas, collecting, sampling and analyzing;

after the reaction is completed, the catalyst (solid) is cooled and collected, and can be recycled.

The analysis results of the gas product obtained after the two-step microwave catalysis are shown in table 1;

table 1: gas product analysis

The iron-nickel metal catalyst supported by carbon black in the embodiment is prepared by the following method: fully mixing carbon black with ferric nitrate and nickel nitrate in distilled water; calcining for 3 hours at 350 ℃ in an inert atmosphere of argon; after the calcination was completed, the catalyst was subjected to reduction treatment in an atmosphere of 5% H2/Ar at 650 ℃ for 6 hours. Finally collecting black powder of the iron-nickel catalyst supported by the carbon black, wherein the mass ratio of the metal iron to the metal nickel to the carbon in the finally obtained catalyst is 3:1: 1.

Example 2

(1) fully and physically and mechanically mixing 50g of crushed polypropylene plastic with 50g of catalyst A (carbon black supported iron-nickel metal catalyst, the mass ratio of iron to nickel to carbon is 3:1:1), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 2000W of power and 2.45GHz of frequency to generate a mixed gas product; after the gas washing treatment, collecting a gas product, and sampling and analyzing the gas product;

(2) loading 10g of catalyst B (activated carbon) in a microwave reactor (2), setting the reaction temperature to be 800 ℃, starting to heat up and preheat from room temperature, wherein the heating rate is 20 ℃/min, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2) for secondary dehydrogenation and purification treatment, carrying out microwave reaction at 800 ℃ for 30 minutes to generate a hydrogen-containing gas product, washing the gas product, collecting the gas product, and sampling and analyzing the gas product;

The analysis results of the gas product obtained after the two-step microwave catalysis are shown in table 2;

table 2: gas product analysis

Example 3

(1) fully and physically and mechanically mixing 50g of crushed polypropylene plastic with 50g of catalyst A (carbon black supported iron-nickel metal catalyst, the mass ratio of iron to nickel to carbon is 3:1:1), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 3000W of power and 2.45GHz of frequency to generate a mixed gas product; after the gas washing treatment, collecting a gas product, and sampling and analyzing the gas product;

(2) loading 20g of catalyst B (the same as the catalyst A in the step (1)) into a microwave reactor (2), setting the reaction temperature to be 750 ℃, starting heating up and preheating from room temperature, wherein the heating up rate is 20 ℃/min, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2) for secondary dehydrogenation and purification treatment, carrying out microwave reaction at 750 ℃ for 30 minutes to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing;

The analysis results of the gas product obtained after the two-step microwave catalysis are shown in table 3;

table 3: gas product analysis

Example 4

(1) fully and physically and mechanically mixing 50g of crushed polypropylene plastic and 50g of catalyst A (carbon black-supported iron oxide catalyst, wherein the mass ratio of iron to carbon is 4: 1), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 3000W of power and 2.45GHz of frequency to generate a mixed gas product; after the gas washing treatment, collecting a gas product, and sampling and analyzing the gas product;

(2) 50g of catalyst B (silicon carbide powder) is loaded in a microwave reactor (2), the reaction temperature is set to 900 ℃, the temperature is raised from room temperature for preheating, the heating rate is 20 ℃/min, the microwave reactor (2) is started while the microwave reactor (1) is opened, and the loaded catalyst B is preheated;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2) for secondary dehydrogenation and purification treatment, carrying out microwave reaction at 900 ℃ for 30 minutes to generate a hydrogen-containing gas product, washing the gas, collecting, sampling and analyzing;

The analysis results of the gas product obtained after the two-step microwave catalysis are shown in table 4;

table 4: gas product analysis

The carbon black supported iron oxide catalyst in the present example was prepared by the following method: dissolving ferric nitrate in distilled water, and mixing with carbon black powder to prepare suspension; and (4) repeatedly and fully stirring the obtained suspension, then putting the suspension into an oven for drying, and grinding the dried sample to obtain powder. Calcining the obtained powder for 3 hours at 350 ℃ in an inert atmosphere of argon, and collecting black powder, namely the iron oxide catalyst supported by the carbon black, wherein the mass ratio of iron to carbon is 4: 1.

example 5

(1) fully and physically and mechanically mixing 50g of crushed polypropylene plastic with 50g of catalyst A (carbon black supported metal iron catalyst, the mass ratio of iron to carbon is 5: 1), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 2000W of power and 2.45GHz of frequency to generate a mixed gas product; after the gas washing treatment, collecting a gas product, and sampling and analyzing the gas product;

(2) loading 20g of catalyst B (same as catalyst A) into a microwave reactor (2), setting the reaction temperature to 850 ℃, starting heating up and preheating from room temperature at the heating rate of 20 ℃/min, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2) for secondary dehydrogenation and purification treatment, carrying out microwave reaction at 850 ℃ for 30 minutes to generate a hydrogen-containing gas product, washing the gas product, collecting the gas product, and sampling and analyzing the gas product;

The analysis results of the gas product obtained after the two-step microwave catalysis are shown in table 5;

table 5: gas product analysis

The carbon black supported metallic iron catalyst in the embodiment is prepared by the following method: fully mixing carbon black and ferric nitrate in distilled water; calcining for 3 hours at 350 ℃ under the inert atmosphere of argon; after the calcination was completed, the catalyst was subjected to reduction treatment in an atmosphere of 5% H2/Ar at a temperature of 650 ℃ for 6 hours. Finally collecting black powder of the carbon black supported metallic iron catalyst, wherein the mass ratio of iron to carbon is 5: 1.

example 6

(1) fully and physically and mechanically mixing 50g of crushed polypropylene plastic with 50g of catalyst A (carbon black supported metal iron catalyst, the mass ratio of iron to carbon is 5: 1), putting the mixture into a microwave reactor (1), purging the mixture for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 4000W power and 2.45GHz frequency to generate a mixed gas product; after the gas washing treatment, collecting a gas product, and sampling and analyzing the gas product;

(2) loading 10g of catalyst B (carbon black powder) in a microwave reactor (2), setting the reaction temperature to be 850 ℃, starting heating up and preheating from room temperature, wherein the heating up rate is 20 ℃/min, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

The analysis results of the gas product obtained after the two-step microwave catalysis are shown in table 6;

table 6: gas product analysis

Example 7

(1) fully and physically and mechanically mixing 50g of crushed polypropylene plastic with 50g of catalyst A (carbon black supported iron-nickel metal catalyst, the mass ratio of metal iron to metal nickel to carbon is 3:1:1), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 3000W of power and 2.45GHz of frequency to generate a mixed gas product; after the gas washing treatment, collecting a gas product, and sampling and analyzing the gas product;

(2) loading 20g of catalyst B (the same as catalyst A) in a microwave reactor (2), setting the reaction temperature to 850 ℃, starting heating up and preheating from room temperature at the heating rate of 20 ℃/min, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2) for secondary dehydrogenation and purification treatment, carrying out microwave reaction at 850 ℃ for 30 minutes to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing;

The analysis results of the gas product obtained after the two-step microwave catalysis are shown in table 7;

table 7: gas product analysis

Example 8

In the present embodiment, a hydrogen production reaction is performed by using polypropylene plastic as a raw material, the process flow is shown in fig. 1, the specific reaction conditions are the same as those in embodiment 7, a recycled carbon black supported iron-nickel metal catalyst is adopted, and the mass ratio of metal iron to metal nickel to carbon is 3:1: 1.

83.2g of the recovered carbon black-supported iron-nickel metal catalyst was mixed with 80g of the pulverized polypropylene plastic, and then introduced into a microwave reactor (1) to purge the reactor for 10 minutes under a nitrogen atmosphere (100 ml/min); setting the microwave power to 3000W and the frequency to 2.45GHz, reacting for 30 minutes, and collecting, sampling and analyzing the obtained gas after gas washing treatment; and introducing the collected gas into a microwave reactor (2), carrying out secondary catalytic dehydrogenation treatment, reacting for 30 minutes, collecting hydrogen, sampling and analyzing.

The analysis results of the gas product obtained after the two-step microwave catalysis used after the catalyst recovery are shown in table 8; as can be seen from the following data, the recovered catalyst can also catalyze dehydrogenation with high efficiency to prepare high-purity hydrogen.

Table 8: gas product analysis

Example 9

(1) fully and physically and mechanically mixing 50g of crushed polypropylene plastic with 50g of catalyst A (iron-nickel metal catalyst, the mass ratio of iron to nickel is 3: 1), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of power 4000W and frequency 2.45GHz to generate a mixed gas product; after the gas washing treatment, collecting a gas product, and sampling and analyzing the gas product;

(2) loading 20g of catalyst B (carbon black supported iron-nickel metal catalyst, the mass ratio of metal iron to metal nickel to carbon is 3:1:1) into a microwave reactor (2), setting the reaction temperature to be 850 ℃, starting temperature rise from room temperature for preheating at the temperature rise rate of 20 ℃/min, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

The analysis results of the gas product obtained after the two-step microwave catalysis are shown in table 9;

table 9: gas product analysis

The iron-nickel metal catalyst in the embodiment is prepared by the following method: fully mixing ferric nitrate, nickel nitrate and citric acid in distilled water; calcining at 450 ℃ for 3 hours; after the calcination was completed, the catalyst was subjected to reduction treatment in an atmosphere of 5% H2/Ar at 650 ℃ for 6 hours. The mass ratio of iron to nickel of the finally obtained iron-nickel alloy catalyst is 3: 1.

example 10

(1) fully and physically and mechanically mixing 50g of crushed polypropylene plastic and 50g of catalyst A (carbon black powder), putting the mixture into a microwave reactor 1, purging the mixture for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of power 4000W and frequency 2.45GHz to generate a mixed gas product; after the gas washing treatment, collecting a gas product, and sampling and analyzing the gas product;

The analysis results of the gas product obtained after the two-step microwave catalysis are shown in table 10;

table 10: gas product analysis

Example 11

(1) fully and physically and mechanically mixing 50g of crushed polypropylene plastic with 50g of catalyst A (iron-nickel metal catalyst, the mass ratio of iron to nickel is 3: 1), putting the mixture into a microwave reactor 1, purging the mixture for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 4000W power and 2.45GHz frequency to generate a mixed gas product; after the gas washing treatment, collecting a gas product, and sampling and analyzing the gas product;

(2) loading 20g of catalyst B (carbon black powder) into a microwave reactor (2), setting the reaction temperature to be 850 ℃, starting heating up and preheating from room temperature, wherein the heating up rate is 20 ℃/min, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

The analysis results of the gas product obtained after the two-step microwave catalysis are shown in table 11;

table 11: gas product analysis

Example 12

In the embodiment, the straw is used as a biomass raw material for hydrogen production, and the process flow is shown in fig. 2, and specifically comprises the following steps:

(1) fully and physically and mechanically mixing 100g of straw scraps with 50g of catalyst A (iron oxide catalyst), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 2000W of power and 2.45GHz of frequency to generate a mixed gas product;

(2) loading 50g of catalyst B (active carbon-loaded metal iron catalyst) in a microwave reactor (2), setting the microwave power to be 3000W and the frequency to be 2.45GHz, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 3000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the results are shown in Table 12;

table 12: gas product analysis

H ₂	53.5％
		CH ₄	3.4％
C ₂₊	0.8％
		CO	36.1％
CO ₂	6.2％

(4) And (4) carrying out Pressure Swing Adsorption (PSA) treatment on the hydrogen-containing gas obtained in the step (3) after gas washing, and collecting hydrogen with the purity of 99.9% after separation and purification.

The catalyst a in this example was prepared as follows: mixing ferric nitrate and citric acid according to a mass ratio of 1:1, and calcining at 450 ℃ for 3 hours to obtain orange iron oxide powder.

The catalyst B in this example was prepared as follows: fully mixing activated carbon and ferric nitrate in distilled water, calcining for 3 hours at 350 ℃ in an argon atmosphere, and then reducing for 6 hours at 650 ℃ in a 5% H2/Ar environment to obtain black powder of the activated carbon-supported metallic iron catalyst, wherein the mass ratio of iron to carbon in the activated carbon-supported metallic iron catalyst is 1: 1.

example 13

In the embodiment, wood chips are used as biomass raw materials for hydrogen production, and the process flow is shown in fig. 2, and specifically comprises the following steps:

(1) fully and physically and mechanically mixing 100g of sawdust and 50g of catalyst A (an iron oxide catalyst prepared by a combustion method), putting the mixture into a microwave reactor (1), purging the mixture for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 3000W of power and 2.45GHz of frequency to generate a mixed gas product;

(2) 50g of catalyst B (active carbon-supported metal iron catalyst prepared by an impregnation method, wherein the mass ratio of carbon to iron is 1:1) is loaded in a microwave reactor (2), the microwave power is set to be 2000W, the frequency is set to be 2.45GHz, the microwave reactor (2) is started while the microwave reactor (1) is opened, and the loaded catalyst B is preheated;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of 2000W power and 2.45GHz frequency to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, and obtaining results shown in Table 13;

table 13: gas product analysis

H ₂	54.4％
		CH ₄	2.9％
C ₂₊	1.1％
		CO	32.9％
CO ₂	8.7％

(4) And (4) after the hydrogen-containing gas product obtained in the step (3) is subjected to gas washing, performing Pressure Swing Adsorption (PSA) treatment, separating and purifying, and collecting hydrogen with the purity of 99.9%.

And after the reaction is completed, cooling and collecting a catalyst (solid) sample for recycling.

Example 14

In the embodiment, the hydrogen production reaction is carried out by taking maple fallen leaves as a biomass raw material, and the process flow is shown in fig. 2, and specifically comprises the following steps:

(1) crushing 100g of maple deciduous leaves, fully and physically and mechanically mixing the crushed maple deciduous leaves with 50g of catalyst A (an iron oxide catalyst prepared by a combustion method), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 2000W of power and 2.45GHz of frequency to generate a mixed gas product;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 2000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the result is shown in Table 14;

table 14: gas product analysis

H ₂	52.9％
		CH ₄	4.6％
C ₂₊	2.2％
		CO	31.6％
CO ₂	8.7％

(4) And (4) washing the hydrogen-containing gas product obtained in the step (3), performing Pressure Swing Adsorption (PSA) treatment, separating and purifying, and collecting hydrogen with the purity of 99.9%.

Example 15

(1) crushing 100g of maple deciduous leaves, fully and physically and mechanically mixing the crushed maple deciduous leaves with 50g of catalyst A (an iron oxide catalyst prepared by a combustion method), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 3000W power and 2.45GHz frequency to generate a mixed gas product;

(2) 50g of catalyst B (an iron oxide catalyst prepared by a combustion method) is loaded in a microwave reactor (2), the microwave power is set to be 2000W, the frequency is set to be 2.45GHz, the microwave reactor (2) is started while the microwave reactor (1) is opened, and the loaded catalyst B is preheated;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 2000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the results are shown in Table 15;

table 15: gas product analysis

H ₂	43.3％
		CH ₄	6.9％
C ₂₊	4.2％
		CO	36.7％
CO ₂	8.9％

(4) And (4) carrying out Pressure Swing Adsorption (PSA) treatment on the hydrogen-containing gas product obtained in the step (3) after gas washing, and collecting hydrogen with the purity of 99.9% after separation and purification.

Example 16

(1) crushing 100g of maple deciduous leaves, fully and physically and mechanically mixing with 50g of catalyst A (an active carbon-supported metal iron catalyst, wherein the mass ratio of carbon to iron is 1:1), putting into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen gas (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 3000W of power and 2.45GHz of frequency to generate a mixed gas product;

(2) 50g of catalyst B (an active carbon-supported metal iron catalyst with a carbon-iron mass ratio of 1:1) is loaded in a microwave reactor (2), the microwave power is set to be 2000W and the frequency is set to be 2.45GHz, the microwave reactor (2) is started while the microwave reactor (1) is opened, and the loaded catalyst B is preheated;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 2000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the result is shown in Table 16;

table 16: gas product analysis

H ₂	60.5％
		CH ₄	2.6％
C ₂₊	0.8％
		CO	33.2％
CO ₂	2.9％

Example 17

(1) fully and physically and mechanically mixing 100g of straw scraps with 50g of catalyst A (activated carbon catalyst), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 2000W of power and 2.45GHz of frequency to generate a mixed gas product;

(2) loading 100g of catalyst B (a silicon carbide-loaded metal iron catalyst with a mass ratio of silicon carbide to iron of 4: 1) into a microwave reactor (2), setting the microwave power to be 3000W and the frequency to be 2.45GHz, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of 3000W power and 2.45GHz frequency to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, and obtaining the results shown in Table 17;

table 17: gas product analysis

H ₂	44.9％
		CH ₄	7.4％
C ₂₊	3.2％
		CO	41.3％
CO ₂	3.2％

The catalyst B in this example was prepared as follows: fully mixing silicon carbide and ferric nitrate in distilled water, calcining for 3 hours at 450 ℃ in an argon atmosphere, and then reducing for 6 hours at 750 ℃ in a 5% H2/Ar environment to obtain black powder of the silicon carbide-supported metallic iron catalyst. The mass ratio of iron to silicon carbide of the finally obtained catalyst powder was 1: 4.

example 18

(1) fully and physically and mechanically mixing 100g of straw scraps with 50g of catalyst A (activated carbon catalyst), putting the mixture into a microwave reactor (1), purging the mixture for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of power 3000W and frequency 2.45GHz to generate a mixed gas product;

(2) loading 100g of catalyst B (a silicon carbide-supported metal iron catalyst prepared by an impregnation method, wherein the mass ratio of silicon carbide to iron is 4: 1) into a microwave reactor (2), setting the microwave power to be 4000W and the frequency to be 2.45GHz, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of 4000W power and 2.45GHz frequency to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, and obtaining results shown in Table 18;

table 18: gas product analysis

H ₂	51.1％
		CH ₄	4.6％
C ₂₊	1.2％
		CO	40.2％
CO ₂	2.9％

The catalyst B in this example was prepared as follows: fully mixing silicon carbide and ferric nitrate in distilled water, calcining for 3 hours at 450 ℃ in an argon atmosphere, and then carrying out reduction treatment for 6 hours at 750 ℃ in a 5% H2/Ar environment to obtain black powder of the silicon carbide-loaded metallic iron catalyst. The mass ratio of iron to silicon carbide of the finally obtained catalyst powder was 1: 4.

example 19

(1) crushing 100g of maple deciduous leaves, fully and physically and mechanically mixing the crushed maple deciduous leaves with 100g of catalyst A (a silicon carbide-supported metal iron catalyst prepared by an impregnation method, wherein the mass ratio of silicon carbide to iron is 4: 1), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 3000W of power and 2.45GHz of frequency to generate a mixed gas product;

(2) loading 100g of catalyst B (a silicon carbide-supported metal iron catalyst prepared by an impregnation method, wherein the mass ratio of silicon carbide to iron is 4: 1) into a microwave reactor (2), setting the microwave power to be 3000W and the frequency to be 2.45GHz, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of 3000W power and 2.45GHz frequency to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, and obtaining results shown in Table 19;

table 19: gas product analysis

H ₂	49.3％
		CH ₄	4.8％
C ₂₊	1.5％
		CO	37.6％
CO ₂	6.8％

Example 20

(2) loading 50g of catalyst B (activated carbon) in a microwave reactor (2), setting the microwave power to be 3000W and the frequency to be 2.45GHz, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of 3000W power and 2.45GHz frequency to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, and obtaining results shown in table 20;

table 20: gas product analysis

Example 21

(1) smashing 100g of maple deciduous leaves, fully and physically and mechanically mixing the smashed maple deciduous leaves with 50g of catalyst A (activated carbon), putting the mixture into a microwave reactor (1), purging the mixture for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of power of 3000W and frequency of 2.45GHz to generate a mixed gas product;

(3) introducing the mixed gas product obtained in the step (1) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 3000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the result is shown in Table 21;

table 21: gas product analysis

H ₂	31.8％
		CH ₄	16.7％
C ₂₊	21.4％
		CO	16.5％
CO ₂	13.6％

In the following examples, samples of household waste are referred to having the composition shown in table 22 below.

TABLE 22 (unit: wt%)

Sample (I)	Humus (food residue/greening waste)	Metal	Plastic material	Paper products	Glass	Leather product	Cloth series	Ash, soil, slag	Wood materials
										A	32.3	1.2	10.3	23.1	0.9	3.4	0	9.9	18.9
B	17.2	0.7	30.9	26.1	5.4	1.2	3.1	5.7	9.7
										C	27.9	5.2	27.5	15.6	7.8	0.1	0.2	15.7	0

Example 22

In the embodiment, a domestic garbage sample a is used as a raw material to perform a hydrogen production reaction, and the process flow is shown in fig. 3, and specifically comprises the following steps:

(1) taking 300g of a household garbage sample A, setting the temperature in a microwave drying reactor at 110 ℃, heating at the rate of 20 ℃/min, carrying out drying treatment for 1 hour to reduce the water content to below 10%, and then crushing;

(2) fully and physically and mechanically mixing a dried and crushed household garbage sample with 100g of catalyst A (iron-nickel alloy catalyst supported by activated carbon), putting the mixture into a microwave reactor (1), purging the mixture for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 2000W of power and 2.45GHz of frequency to generate a mixed gas product;

(3) loading 100g of catalyst B (iron oxide catalyst) in a microwave reactor (2), setting the microwave power to be 4000W and the frequency to be 2.45GHz, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of 4000W power and 2.45GHz frequency to generate a hydrogen-containing gas product, washing the gas, collecting the gas product, sampling and analyzing the gas product, wherein the result is shown in Table 23;

table 23: gas product analysis

H ₂	48.3％
		CH ₄	2.4％
C ₂₊	1.1％
		CO	42.3％
CO ₂	5.9％

(5) And (4) carrying out Pressure Swing Adsorption (PSA) treatment on the hydrogen-containing gas product obtained in the step (4) after gas washing, and collecting hydrogen with the purity of 99.9% after separation and purification.

The catalyst a in this example was prepared as follows: fully mixing activated carbon with ferric nitrate and nickel nitrate in distilled water; calcining for 3 hours at 350 ℃ under the inert atmosphere of argon; after completion of the calcination, the resultant was subjected to a reduction treatment in a 5% H2/Ar atmosphere at 650 ℃ for 6 hours. Finally, collecting the activated carbon supported iron-nickel alloy catalyst, wherein the mass ratio of carbon to iron to nickel of the finally obtained catalyst is 7: 2: 1.

the catalyst B in this example was prepared as follows: mixing ferric nitrate and citric acid according to the mass ratio of 1:1, and calcining at 350 ℃ for 3 hours to obtain orange iron oxide powder.

Example 23

In this embodiment, a domestic waste sample B is used as a raw material to perform a hydrogen production reaction, and the process flow is shown in fig. 3, and specifically includes the following steps:

(1) taking 300g of a household garbage sample B, setting the temperature in a microwave drying reactor at 110 ℃, heating at the rate of 20 ℃/min, carrying out drying treatment for 1 hour to reduce the water content to below 10%, and then crushing;

(2) fully and physically and mechanically mixing a dried and crushed household garbage sample with 100g of catalyst A (an activated carbon-supported iron-nickel alloy catalyst; the mass ratio of carbon to iron to nickel is 7: 2: 1), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 2000W power and 2.45GHz frequency to generate a mixed gas product;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 4000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the result is shown in Table 24;

table 24: gas product analysis

H ₂	65.7％
		CH ₄	3.1％
C ₂₊	0.7％
		CO	24％
CO ₂	6.5％

Example 24

In the embodiment, a domestic waste sample C is used as a raw material to perform a hydrogen production reaction, and the process flow is shown in fig. 3, and specifically comprises the following steps:

(1) taking 300g of a household garbage sample C, setting the temperature in a microwave drying reactor to be 110 ℃, heating at the rate of 20 ℃/min, carrying out drying treatment for 1 hour to reduce the water content to be below 10%, and then crushing;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 4000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the result is shown in Table 25;

table 25: gas product analysis

H ₂	56.5％
		CH ₄	2.4％
C ₂₊	1.1％
		CO	33.1％
CO ₂	6.9％

Example 25

(3) 50g of catalyst B (same as catalyst A, an active carbon supported iron-nickel alloy catalyst; the mass ratio of carbon to iron to nickel is 7: 2: 1) is loaded in a microwave reactor (2), the microwave power is set to 3000W, the frequency is set to 2.45GHz, the microwave reactor (2) is started while the microwave reactor (1) is opened, and the loaded catalyst B is preheated;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 3000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the results are shown in Table 26;

table 26: gas product analysis

H ₂	68.8％
		CH ₄	2.3％
C ₂₊	0.9％
		CO	20.3％
CO ₂	7.7％

(5) And (5) after the hydrogen-containing gas product obtained in the step (4) is subjected to gas washing, Pressure Swing Adsorption (PSA) treatment is carried out, and after separation and purification, the hydrogen with the purity of 99.9% is collected.

Example 26

(2) fully and physically and mechanically mixing a dried and crushed household garbage sample with 50g of catalyst A (activated carbon), putting the mixture into a microwave reactor (1), purging the mixture for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 2000W of power and 2.45GHz of frequency to generate a mixed gas product;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of 4000W power and 2.45GHz frequency to generate a hydrogen-containing gas product, washing the gas, collecting the gas product, sampling and analyzing the gas product, wherein the result is shown in Table 27;

table 27: gas product analysis

H ₂	59.2％
		CH ₄	7.5％
C ₂₊	2.3％
		CO	24.5％
CO ₂	6.5％

(5) And (4) after the hydrogen-containing gas product obtained in the step (4) is subjected to gas washing, performing Pressure Swing Adsorption (PSA) treatment, separating and purifying, and collecting hydrogen with the purity of 99.9%.

Example 27

In the embodiment, a domestic garbage sample C is used as a raw material to perform a hydrogen production reaction, and the process flow is shown in fig. 3, and specifically comprises the following steps:

(1) taking 300g of a household garbage sample C, setting the temperature in a microwave drying reactor at 110 ℃, heating at the rate of 20 ℃/min, carrying out drying treatment for 1 hour to reduce the water content to below 10%, and then crushing;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 4000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the result is shown in Table 28;

table 28: gas product analysis

H ₂	53.9％
		CH ₄	8.1％
C ₂₊	1.8％
		CO	31.9％
CO ₂	4.3％

Example 28

(1) taking a 300g household garbage sample A, setting the temperature in a microwave drying reactor at 110 ℃, heating at the rate of 20 ℃/min, carrying out drying treatment for 1 hour to reduce the water content to below 10%, and then crushing;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 4000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the results are shown in Table 29;

table 29: gas product analysis

H ₂	43.8％
		CH ₄	3.7％
C ₂₊	1.5％
		CO	46.3％
CO ₂	4.7％

Example 29

(2) fully and physically and mechanically mixing a dried and crushed household garbage sample with 100g of catalyst A (a silicon carbide-supported iron metal catalyst, wherein the mass ratio of silicon carbide to iron is 5: 1), putting the mixture into a microwave reactor (1), purging the mixture for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 3000W of power and 2.45GHz of frequency to generate a mixed gas product;

(3) 100g of catalyst B (iron-nickel alloy, the mass ratio of iron to nickel is 4: 1) is loaded in a microwave reactor (2), the microwave power is set to be 3000W, the frequency is set to be 2.45GHz, the microwave reactor (2) is started while the microwave reactor (1) is opened, and the loaded catalyst B is preheated;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 3000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the results are shown in a table 30;

table 30: gas product analysis

H ₂	49.5％
		CH ₄	4.3％
C ₂₊	0.9％
		CO	37.6％
CO ₂	7.7％

The catalyst a in this example was prepared as follows: fully mixing silicon carbide and ferric nitrate in distilled water; calcining for 3 hours at 350 ℃ under the inert atmosphere of argon; after the calcination was completed, the catalyst was subjected to reduction treatment in an atmosphere of 5% H2/Ar at 650 ℃ for 6 hours. Finally collecting black powder of the silicon carbide supported metallic iron catalyst, wherein the mass ratio of silicon carbide to iron in the finally obtained catalyst is 5: 1.

the catalyst B in this example was prepared as follows: fully mixing ferric nitrate, nickel nitrate and citric acid in distilled water; calcining at 450 ℃ for 3 hours; after the calcination was completed, the catalyst was subjected to reduction treatment in an atmosphere of 5% H2/Ar at 650 ℃ for 6 hours. The mass ratio of iron to nickel of the finally obtained iron-nickel alloy catalyst is 4: 1.

example 30

(1) taking 300g of a household garbage sample B, setting the temperature in a microwave drying reactor to be 110 ℃, heating at the rate of 20 ℃/min, carrying out drying treatment for 1 hour to reduce the water content to be below 10%, and then crushing;

(2) fully and physically and mechanically mixing a dried and crushed household garbage sample with 100g of catalyst A (silicon carbide supported iron metal catalyst, the mass ratio of silicon carbide to iron is 5: 1), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of 3000W of power and 2.45GHz of frequency to generate a mixed gas product;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 3000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the result is shown in table 31;

table 31: gas product analysis

H ₂	61.3％
		CH ₄	3.3％
C ₂₊	1.7％
		CO	24.8％
CO ₂	8.9％

Example 31

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 3000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the result is shown in a table 32;

table 32: gas product analysis

Example 32

In the embodiment, a domestic waste sample B is used as a raw material to perform a hydrogen production reaction, and the process flow is shown in fig. 3, and specifically comprises the following steps:

(2) fully and physically and mechanically mixing a dried and crushed household garbage sample with 100g of catalyst A (iron-nickel alloy, the mass ratio of iron to nickel is 4: 1), putting the mixture into a microwave reactor (1), purging for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of power of 3000W and frequency of 2.45GHz to generate a mixed gas product;

(3) 50g of catalyst B (same as catalyst A, iron-nickel alloy and iron-nickel mass ratio of 4: 1) is loaded in a microwave reactor (2), the microwave power is set to be 4000W and the frequency is set to be 2.45GHz, the microwave reactor (2) is started while the microwave reactor (1) is opened, and the loaded catalyst B is preheated;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 4000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the result is shown in Table 33;

table 33: gas product analysis

H ₂	66.7％
		CH ₄	2.1％
C ₂₊	1.1％
		CO	17.4％
CO ₂	12.7％

(5) And (4) performing Pressure Swing Adsorption (PSA) treatment on the hydrogen-containing gas product obtained in the step (4), separating and purifying, and collecting hydrogen with the purity of 99.9%.

Example 33

(3) 50g of catalyst B (same as catalyst A, silicon carbide supported iron metal catalyst with the mass ratio of silicon carbide to iron being 5: 1) is loaded in a microwave reactor (2), the microwave power is set to be 4000W and the frequency is set to be 2.45GHz, the microwave reactor (2) is started while the microwave reactor (1) is opened, and the loaded catalyst B is preheated;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 4000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the result is shown in Table 34;

table 34: gas product analysis

H ₂	64.3％
		CH ₄	3.3％
C
	₂₊	1％
CO			21.6％
	CO ₂	9.8％

Example 34

(3) loading 100g of catalyst B (silicon carbide) in a microwave reactor (2), setting the microwave power to be 4000W and the frequency to be 2.45GHz, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of 4000W power and 2.45GHz frequency to generate a hydrogen-containing gas product, washing the gas, collecting the gas product, sampling and analyzing the gas product, wherein the result is shown in Table 35;

table 35: gas product analysis

H ₂	41.2％
		CH ₄	18.9％
C ₂₊	9.1％
		CO	21.1％
CO ₂	9.7％

Example 35

(2) fully and physically and mechanically mixing a dried and crushed household garbage sample with 100g of catalyst A (activated carbon), putting the mixture into a microwave reactor (1), purging the mixture for 10 minutes under the condition of nitrogen (100ml/min), and carrying out microwave reaction for 30 minutes under the conditions of power 3000W and frequency 2.45GHz to generate a mixed gas product;

(3) loading 100g of catalyst B (activated carbon) in a microwave reactor (2), setting the microwave power to be 4000W and the frequency to be 2.45GHz, starting the microwave reactor (2) while opening the microwave reactor (1), and preheating the loaded catalyst B;

(4) introducing the mixed gas product obtained in the step (2) into a microwave reactor (2), carrying out microwave reaction for 30 minutes under the conditions of power 4000W and frequency 2.45GHz to generate a hydrogen-containing gas product, carrying out gas washing, collecting, sampling and analyzing, wherein the result is shown in Table 36;

table 36: gas product analysis

H ₂	31.8％
		CH ₄	15.1％
C ₂₊	22.4％
		CO	12.6％
CO ₂	18.1％

The percentages in the above gas product analysis tables are in mole percent.

Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that modifications and improvements can be made thereto without departing from the scope of the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. A method for producing hydrogen by using carbon-containing solids is characterized in that the method takes the carbon-containing solids as raw materials and comprises two stages of microwave catalytic treatment, wherein:

the second stage of microwave catalysis is to perform secondary microwave treatment on the mixed gas obtained by the first stage of microwave catalysis under the action of a catalyst B to generate hydrogen-containing gas;

the catalyst A and/or the catalyst B is selected from carbon materials, transition metal materials and transition metal materials taking carbon materials as carriers; the compositions of the catalyst A and the catalyst B are the same or different.

2. The method of claim 1, wherein the carbon material is selected from the group consisting of carbon black, activated carbon, and silicon carbide; and/or the presence of a gas in the gas,

the transition metal material comprises at least one of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum and tungsten series metal materials;

preferably, the transition metal material is selected from an iron-nickel based metal material, a molybdenum based compound, or a chromium based compound;

wherein the iron-nickel metal material is selected from one or more of metallic iron, ferrous oxide, ferric oxide, iron carbide, ferroferric oxide, metallic nickel, nickel oxide, iron-nickel alloy and mixed iron-nickel oxide;

and/or, the molybdenum-based compound is selected from molybdenum oxide or molybdenum carbide;

and/or the chromium-based compound is selected from a chromium oxide compound or chromium carbide.

3. The method according to claim 1 or 2, wherein the catalyst a is an iron-nickel based metal material or an iron-nickel based metal material supported on a carbon material, preferably metallic iron, iron oxide, an iron-nickel alloy or a metallic iron, iron oxide or an iron-nickel alloy supported on a carbon material;

the catalyst B is a carbon material, an iron-nickel metal material or an iron-nickel metal material taking the carbon material as a carrier, preferably a carbon material, metallic iron, ferric oxide, an iron-nickel alloy or metallic iron, ferric oxide or an iron-nickel alloy taking the carbon material as a carrier.

4. The method according to any one of claims 1 to 3, wherein the carbon-containing solid comprises at least one of polyolefin plastic, biomass, man-made organic high molecular polymer, biochar, coal, asphalt, coke, paraffin, chemical fiber, tires, medical waste, and household garbage;

preferably, the carbonaceous solid is selected from the group consisting of polypropylene plastic, household waste and biomass.

5. The method according to any one of claims 1 to 4, wherein the mass ratio of the carbon material as the carrier to the metal material supported thereon is (0.1 to 10): 1, preferably (0.1-5): 1.

6. the method according to claim 1, wherein the mass ratio of the carbon-containing solid to the catalyst A in the method is (0.5-10): 1;

and/or the mass ratio of the catalyst A to the catalyst B is (1-5): (1-2).

7. The method according to any one of claims 1 to 6, wherein the power of the first stage of microwave catalytic treatment is 500 to 8000W, preferably 1000 to 6000W;

the second stage of microwave catalytic treatment adopts 500-8000W of power, preferably 1000-6000W of power, or the temperature of the second stage of microwave catalytic treatment is 600-1000 ℃.

8. The method according to claim 1, wherein the frequency of the first stage and/or the second stage of microwave catalytic treatment is 0.3 to 3GHz, preferably 2.45GHz or 915 MHz;

preferably, the time of the first stage of microwave catalytic treatment is 20-60 min, and/or the time of the second stage of microwave catalytic treatment is 20-60 min.

9. The method of claim 1, wherein the first stage microwave catalytic treatment and the second stage microwave catalytic treatment are performed in an inert environment having an oxygen content of less than 5000ppm at standard atmospheric pressure.

10. The method according to any one of claims 1 to 9, further comprising: after the first stage of microwave catalysis and/or the second stage of microwave catalysis are finished, separating and purifying the product;