CN115180591A - A method for producing hydrogen from domestic waste - Google Patents

Abstract

The invention relates to a method for producing hydrogen by domestic garbage, which takes the domestic garbage as a raw material and comprises two sections of continuous microwave catalytic treatment. The efficient and low-carbon garbage hydrogen production method based on the microwave technology realizes high-selectivity, efficient and complete dehydrogenation treatment through the interaction of the catalyst and the microwave, realizes the preparation of high-purity hydrogen from garbage, does not generate harmful substances, has low emission, and is an environment-friendly low-carbon hydrogen production method.

Description

A method for producing hydrogen from domestic waste

technical field

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

Background technique

MSW is a heterogeneous mixture consisting of various substances. Municipal solid waste generally includes humus (such as food residues and green waste), metal substances, plastics, paper, glass, leather products, cloth, ash and wood, etc. Different from the fixed characteristics of a single substance, in the process of urban waste treatment, it is often faced with the problem of a wide range of physical and chemical properties. At present, when dealing with domestic waste, methods including heat treatment (such as pyrolysis, gasification and incineration) and biological methods (such as composting) are often used according to different physical and chemical properties of waste.

At present, the treatment of urban domestic waste mainly focuses on the treatment of harmless and reduced amount. The most common domestic waste disposal method in my country is the sanitary landfill method. However, most of these domestic wastes have not been classified or harmless, and are often mixed with toxic substances and other recyclable substances. These wastes are directly landfilled without treatment, which will not only cause serious secondary pollution, but also cause waste of some available resources. Economic losses. Therefore, in recent years, more and more attention has been paid to the recycling of waste treatment. The significance of recycling waste is to recycle useful substances, and at the same time make it harmless, reduce, and energy.

As an alternative fossil energy, hydrogen energy is an important option to achieve carbon neutrality, and it has received more and more attention and attention in recent years. Hydrogen production is an important component and key factor in promoting the hydrogen energy economy. However, the current hydrogen production methods still rely on fossil fuels, such as hydrogen production from natural gas reforming and coke oven gas production. The production of hydrogen by these methods produces large amounts of carbon dioxide emissions, often as an industrial by-product. Therefore, developing a hydrogen production method with low energy consumption and low carbon is the ultimate solution to the hydrogen demand in the hydrogen economy.

According to the different composition of waste and its different physical and chemical properties, researchers have developed different processing methods, including reforming, pyrolysis, biological methods, etc. to achieve hydrogen production from different waste components. However, due to the complexity of the waste structure, hydrogen production from waste usually requires multi-step complex reaction paths, harsh reaction conditions, such as high temperature and high pressure, and the processing process produces a large amount of carbon dioxide emissions, resulting in secondary pollution.

Therefore, there is an urgent need to develop a high-yield hydrogen production method using household waste as a raw material, while avoiding the massive emission of harmful substances.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the defects of the prior art, and to provide a method for producing hydrogen by microwave catalysis from household garbage. The method realizes the hydrogen energy treatment of domestic waste under mild conditions, effectively improves the hydrogen yield, reduces by-products, and reduces carbon emissions in the process.

Specifically, the present invention provides a method for producing hydrogen from domestic waste, wherein the method uses domestic waste as a raw material to perform microwave catalytic treatment to prepare hydrogen-containing gas; the catalyst used in the microwave catalysis is selected from carbon materials and transition metal materials. Or transition metal materials supported by carbon materials.

The household garbage described in the present invention includes one or more of the following types: food waste (kitchen waste), such as leftover food, melon rind, fruit crumbs, etc., and can also include food packaging plastic bags, wrapping paper, snack bags , beverage bottles, etc.; other general garbage (loose garbage), such as paper, waste plastics, cans, glass bottles, ceramics, wood chips, old clothing, old shoes and hats, waste furniture, waste pen tubes, paints and other daily wastes and Inorganic ash, etc.; biomass waste, such as plant residues, leaves, branches, etc.

In some embodiments, the household garbage of the present invention includes one or more of the following: humus, metal items, plastic items, paper items, glass, leather products, cloth items, ash/soil/slag, wood thing.

In some embodiments, in the household garbage of the present invention, the content of humus is in the range of 5-50 wt %, the content of metal objects is in the range of 0-10 wt %, the content of plastic objects is in the range of 5-50 wt %, and the content of paper objects is in the range of 0 wt %. ～30wt%, glass content range is 0～10wt%, leather product content range is 0～10wt%, cloth content range is 0～10wt%, lime soil residue content range is 0～30wt%, wood product content range is 0～30wt% 0～30wt%.

In some embodiments, in the household garbage of the present invention, the content of humus is in the range of 15-35 wt %, the content of metal items is in the range of 0-7 wt %, the content of plastic items is in the range of 10-35 wt %, and the content of paper items is in the range of 15 wt %. ～28wt%, glass content range is 0～8wt%, leather product content range is 0～5wt%, cloth content range is 0～4wt%, lime soil slag content range is 5～16wt%, wood product content range is 5～16wt% 0～20wt%.

In some embodiments, in the household garbage of the present invention, the content of humus is in the range of 15-30 wt %, the content of metal items is in the range of 0.5-6 wt %, the content of plastic items is in the range of 25-35 wt %, and the content of paper items is in the range of 15 wt %. ～28wt%, glass content range is 5～8wt%, leather product content range is 0～1.5wt%, cloth content range is 0～4wt%, lime soil slag content range is 5～16wt%, wood product content range is 5～16wt% 0 to 10 wt %.

In some preferred embodiments, in the household garbage of the present invention, the content of humus is in the range of 15-20wt%, the content of metal objects is in the range of 0.5-1.5wt%, the content of plastic objects is in the range of 28-32wt%, and the content of paper objects is in the range of 28-32wt%. 25-28wt%, glass content range is 5-7wt%, leather product content range is 1.0-1.5wt%, cloth content range is 3-4wt%, lime soil residue content range is 5-6wt%, wood products The content ranges from 8 to 10 wt %.

Before carrying out the microwave catalytic treatment, the present invention firstly performs drying treatment on the domestic garbage to remove a large amount of water contained in the garbage and increase the efficiency of the subsequent dehydrogenation treatment. The drying treatment of the present invention can adopt the drying method of domestic waste known in the art.

In some embodiments, the drying process is to reduce the moisture content of the domestic waste raw material to less than 10%.

In some embodiments, the drying treatment adopts microwave treatment.

In some embodiments, after the dried domestic garbage is pulverized, subsequent microwave catalytic treatment is performed. In actual operation, it is preferable to put the dried and pulverized household garbage into the microwave catalytic reactor.

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

In some embodiments, the transition metal material of the present invention is selected from iron-nickel series metal materials, preferably selected from metal iron, iron oxide, iron tetroxide, metal nickel, nickel oxide, iron-nickel alloy and mixed iron-nickel oxide thing. Wherein, the mass ratio of iron to nickel in the iron-nickel alloy is preferably (2-5):1.

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

In some embodiments, the carbon material used as the carrier is activated carbon, and the mass ratio of the activated carbon to the metal material supported thereon is (2-4):1.

In some embodiments, the carbon material used as the carrier is silicon carbide, and the mass ratio of the silicon carbide to the metal material supported thereon is (3-5):1.

In some embodiments, the microwave power used in the microwave catalytic treatment is 1000W-6000W, and the frequency of the microwave treatment is 0.3-3GHz.

Preferably, the microwave power used in the microwave catalytic treatment is 2000W-4000W, and the frequency of the microwave treatment is 2.45GHz or 915MHz, more preferably 2.45GHz.

In some embodiments, the microwave catalytic treatment is performed in an inert environment at standard atmospheric pressure with an oxygen content below 5000 ppm.

In some embodiments, the duration of the microwave catalytic treatment is 30-60 minutes.

As a preferred embodiment, the method for producing hydrogen from domestic waste provided by the present invention includes two stages of microwave catalytic treatment continuously performed; wherein:

The first stage of microwave catalytic treatment is to carry out a microwave treatment on domestic waste under the action of catalyst A to generate mixed gas;

The second stage of microwave catalytic treatment is to perform secondary microwave treatment on the obtained mixed gas under the action of catalyst B to generate hydrogen-containing gas;

Wherein, the catalyst A and/or the catalyst B are selected from carbon materials, transition metal materials or transition metal materials supported by carbon materials; the catalyst A and the catalyst B may be the same or different.

In some embodiments, the catalyst A is a carbon material, an iron-nickel alloy, or an iron-nickel alloy or metal iron catalyst supported by a carbon material. Wherein, the carbon material is preferably activated carbon or silicon carbide.

In some embodiments, the catalyst B is a carbon material, iron oxide, iron-nickel alloy, or iron-nickel alloy or metal iron catalyst supported by carbon material. Wherein, the carbon material is preferably activated carbon or silicon carbide.

In some preferred embodiments, the catalyst A is an activated carbon-supported iron-nickel alloy, an activated carbon, an iron-nickel alloy or a silicon carbide-supported metallic iron.

In some preferred embodiments, the catalyst B is iron oxide, activated carbon-supported iron-nickel alloy, iron-nickel alloy or silicon carbide-supported metallic iron.

In some embodiments, in the activated carbon-supported iron-nickel alloy, the mass ratio of activated carbon, iron, and nickel is (5-10): (1-3): (1-2), for example, the mass ratio of activated carbon, iron, and nickel 7:2:1.

In some embodiments, the mass ratio of iron to nickel in the iron-nickel alloy is (2-5):1, for example, the mass ratio of iron and nickel in the iron-nickel alloy is 4:1.

In some embodiments, the mass ratio of silicon carbide to metal iron in the silicon carbide-supported metal iron is (3-5):1, for example, 5:1.

Further preferably, both the catalyst A and the catalyst B are iron-nickel alloys or activated carbon-supported iron-nickel alloys.

In some embodiments, the mass ratio of domestic waste to catalyst A used in the method of the present invention is (1-10):1.

In some embodiments, the mass ratio of catalyst A to catalyst B used in the method of the present invention is (1-2):(1-2), for example, it may be 1:1, 1:2 or 2:1.

In some embodiments, the power of the first microwave treatment is 2000W to 3000W; the power of the second microwave treatment is 2000W to 4000W, which is the same as or different from the power of the first microwave treatment.

In some embodiments, the frequency of both the primary microwave treatment and the secondary microwave treatment is 2.45 GHz.

In some embodiments, the time of the first stage of microwave catalytic treatment is preferably 20-40 min. The time of the second microwave catalytic treatment is preferably 20-40 min.

In some embodiments, the first stage of microwave catalytic treatment and the second stage of microwave catalytic treatment use a first microwave reactor and a second microwave reactor in series; preferably, during the first stage of microwave catalytic treatment, the second microwave Catalyst B in the reactor is preheated. The two-stage microwave catalytic treatment of the present invention can be carried out in a microwave reactor equipped with a conventional microwave source (including a magnetron or a solid-state source).

In some more specific embodiments, when the household garbage is subjected to microwave catalytic treatment in the first microwave reactor, microwave preheating is performed on the catalyst B in the second microwave reactor; The reaction product is then passed into the second microwave reactor for secondary microwave treatment.

In some embodiments, the method provided by the present invention further comprises: performing a separation and purification step on the hydrogen-containing gas product.

The separation and purification can adopt methods known in the art. In some embodiments, the separation and purification includes gas scrubbing and/or pressure swing adsorption (PSA) treatment.

In the method provided by the invention, after the reaction is completed, the catalyst is cooled to collect the catalyst, and the recycling of the catalyst can be realized.

The microwave catalysis used in the present invention, or called microwave-induced catalysis, is different from the so-called reaction accelerated by the microwave thermal effect. The microwave thermal effect usually does not involve a catalyst. induction. The invention realizes the efficient preparation of hydrogen through microwave catalytic treatment under the action of the catalyst.

The catalyst used in the present invention can be prepared by chemical preparation methods such as impregnation method, precipitation method, and combustion method known in the art. For transition metal materials supported by carbon materials or iron-based metal materials supported by carbon materials, metals can be mixed with the support materials in the form of precursors, including but not limited to nitrates, Chlorates, organometallic compounds, etc. In order to better ensure the effect of the catalyst to absorb microwaves, the particle size of the catalyst used in the present invention is less than 50 μm, and preferably the particle size of the catalyst is 50 nm˜10 μm.

The invention dries the domestic garbage by microwave heating, and then uses the microwave catalytic technology to dehydrogenate and decompose the domestic garbage. The dried domestic garbage is rapidly decomposed through the interaction of the microwave and the catalyst, and selectively dehydrogenated to generate compound hydrogen. The mixed gas (which contains small gas molecules such as hydrogen, hydrocarbons, carbon oxides, etc.) is further subjected to secondary dehydrogenation purification treatment by microwave catalysis, and the mixed gas is subjected to secondary catalytic dehydrogenation treatment to remove small molecules in the mixed gas. Hydrocarbons, a hydrogen-containing gas with a high hydrogen content is obtained. The hydrogen-containing gas is then purified by scrubbing and pressure swing adsorption (PSA) to obtain high-purity hydrogen.

The invention is a low-cost, high-efficiency and low-carbon clean hydrogen production method from domestic waste, which realizes the harmlessness, reduction and hydrogen energy treatment of domestic waste; and compared with traditional incineration and pyrolysis And the reforming method can realize high-selectivity in-situ pyrolysis-catalytic dehydrogenation, and greatly improve the yield of hydrogen.

Compared with the prior art, the microwave used in the present invention selectively heats the catalyst without heating raw materials such as garbage, which greatly reduces the side reactions caused by pyrolysis, and at the same time, also improves the conversion efficiency of the catalyst and promotes selective dehydrogenation. In particular, the present invention effectively solves the problem of incomplete single microwave catalytic treatment through two-stage continuous microwave catalytic treatment, and the gas-liquid mixed intermediate product containing small molecular hydrocarbons produced in the treatment process is subjected to secondary treatment. Dehydrogenation treatment, thereby increasing hydrogen yield and fully decomposing waste. The invention utilizes the characteristics of instantaneous microwave heating, rapidly dries domestic garbage, and performs two consecutive microwave catalytic treatments to prepare high-quality hydrogen. The method realizes the hydrogen energy treatment of domestic waste under mild conditions, effectively improves the hydrogen yield, reduces the generation of by-products, and reduces the carbon emission in the process.

Description of drawings

Fig. 1 is a process flow diagram of a method for producing hydrogen from domestic waste provided by the present invention.

Detailed ways

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

The composition of the household waste samples involved in the following examples is shown in Table 1 below.

Table 1 (unit: wt%)

sample Humus (food residue/green waste) Metal plastic paper Glass Leather product cloth Ash, dirt, slag wood 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 1

In this example, the domestic waste sample A is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample A, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physically and mechanically mix the dried and pulverized household garbage sample with 100 g of catalyst A (an activated carbon-supported iron-nickel alloy catalyst), put it into the microwave reactor (1), and under nitrogen conditions (100 ml/min) ), carry out purging for 10 minutes, microwave reaction for 30 minutes under the condition of power 2000W, frequency 2.45GHz, generate mixed gas product;

(3) Get 100g catalyst B (iron oxide catalyst) and load it in the microwave reactor (2), set the microwave power to 4000W, the frequency of 2.45GHz, and open the microwave reactor (2) while opening the microwave reactor (1). ), preheating the loaded catalyst B;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 4000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 2;

Table 2: Gas Product Analysis

H₂ 48.3% CH₄ 2.4% C₂₊ 1.1% CO 42.3% CO₂ 5.9%

(5) The hydrogen-containing gas product obtained in step (4) is subjected to pressure swing adsorption (PSA) treatment after being scrubbed, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Catalyst A in this example was prepared by the following method: fully mixing activated carbon with ferric nitrate and nickel nitrate in distilled water; calcining at 350° C. for 3 hours under an inert atmosphere of argon; after calcining, at 5% The reduction treatment was performed in an H ₂ /Ar environment, and the reduction treatment conditions were 650° C. for 6 hours. Finally, the activated carbon-supported iron-nickel alloy catalyst was collected, and the mass ratio of carbon, iron and nickel of the catalyst finally obtained was 7:2:1.

The catalyst B in this example was prepared by the following method: after mixing ferric nitrate and citric acid in a mass ratio of 1:1, calcined at 350° C. for 3 hours to obtain orange iron oxide powder.

After the reaction is completed, the catalyst (solid) is collected by cooling and can be recycled.

Example 2

In this example, the domestic waste sample B is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample B, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physically and mechanically mix the dried and pulverized household garbage sample with 100 g of catalyst A (an iron-nickel alloy catalyst supported by activated carbon; the mass ratio of carbon, iron and nickel is 7:2:1), and put into In the microwave reactor (1), purging was carried out for 10 minutes under nitrogen conditions (100ml/min), and the microwave reaction was carried out under the conditions of power 2000W and frequency 2.45GHz for 30 minutes to generate mixed gas products;

(3) Get 100g catalyst B (iron oxide catalyst) and load it in the microwave reactor (2), set the microwave power to 4000W, the frequency of 2.45GHz, and open the microwave reactor (2) while opening the microwave reactor (1). ), preheating the loaded catalyst B;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 4000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 3;

Table 3: Gas Product Analysis

H₂ 65.7% CH₄ 3.1% C₂₊ 0.7% CO twenty four% CO₂ 6.5%

(5) The hydrogen-containing gas product obtained in step (4) is subjected to pressure swing adsorption (PSA) treatment after being scrubbed, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Example 3

In this embodiment, the domestic waste sample C is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample C, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physically and mechanically mix the dried and pulverized household garbage sample with 100 g of catalyst A (an iron-nickel alloy catalyst supported by activated carbon; the mass ratio of carbon, iron and nickel is 7:2:1), and put into In the microwave reactor (1), purging was carried out for 10 minutes under nitrogen conditions (100ml/min), and the microwave reaction was carried out under the conditions of power 2000W and frequency 2.45GHz for 30 minutes to generate mixed gas products;

(3) Get 100g catalyst B (iron oxide catalyst) and load it in the microwave reactor (2), set the microwave power to 4000W, the frequency of 2.45GHz, and open the microwave reactor (2) while opening the microwave reactor (1). ), preheating the loaded catalyst B;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 4000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 4;

Table 4: Gas Product Analysis

H₂ 56.5% CH₄ 2.4% C₂₊ 1.1% CO 33.1% CO₂ 6.9%

(5) The hydrogen-containing gas product obtained in step (4) is subjected to pressure swing adsorption (PSA) treatment after being scrubbed, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Example 4

In this example, the domestic waste sample B is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample B, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physically and mechanically mix the dried and pulverized household garbage sample with 100 g of catalyst A (an iron-nickel alloy catalyst supported by activated carbon; the mass ratio of carbon, iron and nickel is 7:2:1), and put into In the microwave reactor (1), purging was carried out for 10 minutes under nitrogen conditions (100ml/min), and the microwave reaction was carried out under the conditions of power 2000W and frequency 2.45GHz for 30 minutes to generate mixed gas products;

(3) get 50g catalyst B (same as catalyst A, it is the iron-nickel alloy catalyst supported by activated carbon; the mass ratio of carbon, iron and nickel is 7:2:1) and load it in microwave reactor (2), set The microwave power is 3000W, the frequency is 2.45GHz, and the microwave reactor (2) is opened while the microwave reactor (1) is opened, and the loaded catalyst B is preheated;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 3000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 5;

Table 5: Gas Product Analysis

H₂ 68.8% CH₄ 2.3% C₂₊ 0.9% CO 20.3% CO₂ 7.7%

(5) The hydrogen-containing gas product obtained in step (4) is scrubbed and subjected to pressure swing adsorption (PSA) treatment, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Example 5

In this example, the domestic waste sample B is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample B, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physically and mechanically mix the dried and pulverized household garbage sample with 50 g of catalyst A (activated carbon), put it into the microwave reactor (1), and blow it for 10 minutes under nitrogen conditions (100 ml/min). Scanning, microwave reaction under the condition of power 2000W and frequency 2.45GHz for 30 minutes to generate mixed gas product;

(3) Get 100g catalyst B (iron oxide catalyst) and load it in the microwave reactor (2), set the microwave power to 4000W, the frequency of 2.45GHz, and open the microwave reactor (2) while opening the microwave reactor (1). ), preheating the loaded catalyst B;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 4000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 6;

Table 6: Gas Product Analysis

H₂ 59.2% CH₄ 7.5% C₂₊ 2.3% CO 24.5% CO₂ 6.5%

(5) The hydrogen-containing gas product obtained in step (4) is scrubbed and subjected to pressure swing adsorption (PSA) treatment, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Example 6

In this embodiment, the domestic waste sample C is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample C, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physically and mechanically mix the dried and pulverized household garbage sample with 50 g of catalyst A (activated carbon), put it into the microwave reactor (1), and blow it for 10 minutes under nitrogen conditions (100 ml/min). Scanning, microwave reaction under the condition of power 2000W and frequency 2.45GHz for 30 minutes to generate mixed gas product;

(3) Get 100g catalyst B (iron oxide catalyst) and load it in the microwave reactor (2), set the microwave power to 4000W, the frequency of 2.45GHz, and open the microwave reactor (2) while opening the microwave reactor (1). ), preheating the loaded catalyst B;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 4000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 7;

Table 7: Gas Product Analysis

H₂ 53.9% CH₄ 8.1% C₂₊ 1.8% CO 31.9% CO₂ 4.3%

(5) The hydrogen-containing gas product obtained in step (4) is scrubbed and subjected to pressure swing adsorption (PSA) treatment, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Example 7

In this example, the domestic waste sample A is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample A, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physically and mechanically mix the dried and pulverized household garbage sample with 50 g of catalyst A (activated carbon), put it into the microwave reactor (1), and blow it for 10 minutes under nitrogen conditions (100 ml/min). Scanning, microwave reaction under the condition of power 2000W and frequency 2.45GHz for 30 minutes to generate mixed gas product;

(3) Get 100g catalyst B (iron oxide catalyst) and load it in the microwave reactor (2), set the microwave power to 4000W, the frequency of 2.45GHz, and open the microwave reactor (2) while opening the microwave reactor (1). ), preheating the loaded catalyst B;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 4000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 8;

Table 8: Gas Product Analysis

(5) The hydrogen-containing gas product obtained in step (4) is scrubbed and subjected to pressure swing adsorption (PSA) treatment, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Example 8

In this example, the domestic waste sample A is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample A, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physico-mechanical mixing of the dried and pulverized household garbage sample with 100 g of catalyst A (iron metal catalyst supported by silicon carbide, the mass ratio of silicon carbide and iron is 5:1), put into a microwave reactor ( 1) in, carry out purging for 10 minutes under nitrogen conditions (100ml/min), microwave reaction under the condition of power 3000W, frequency 2.45GHz for 30 minutes, generate mixed gas product;

(3) get 100g catalyst B (iron-nickel alloy, the mass ratio of iron and nickel is 4:1) and load it in microwave reactor (2), set microwave power to be 3000W, frequency 2.45GHz, open microwave reactor ( 1) at the same time, the microwave reactor (2) is opened, and the loaded catalyst B is preheated;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 3000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 9;

Table 9: Gas Product Analysis

H₂ 49.5% CH₄ 4.3% C₂₊ 0.9% CO 37.6% CO₂ 7.7%

(5) The hydrogen-containing gas product obtained in step (4) is scrubbed and subjected to pressure swing adsorption (PSA) treatment, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Catalyst A in this example was prepared by the following method: fully mixing silicon carbide and ferric nitrate in distilled water; calcining at 350°C for ₃ hours in an inert atmosphere of argon; The catalyst was subjected to reduction treatment in an Ar environment, and the reduction treatment conditions were 650° C. for 6 hours. The black powder of the metal iron catalyst supported by silicon carbide was finally collected, and the mass ratio of silicon carbide and iron in the finally obtained catalyst was 5:1.

The catalyst B in this example was prepared by the following method: ferric nitrate, nickel nitrate and citric acid were fully mixed in distilled water; calcined at 450°C for 3 hours; after the calcination was completed, the catalyst was subjected to 5% H ₂ /Ar environment For the reduction treatment, the reduction treatment conditions were 650° C. for 6 hours. The iron-nickel mass ratio of the finally obtained iron-nickel alloy catalyst is 4:1.

Example 9

In this example, the domestic waste sample B is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample B, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physico-mechanical mixing of the dried and pulverized household garbage sample with 100 g of catalyst A (iron metal catalyst supported by silicon carbide, the mass ratio of silicon carbide and iron is 5:1), put into a microwave reactor ( 1) in, carry out purging for 10 minutes under nitrogen conditions (100ml/min), microwave reaction under the condition of power 3000W, frequency 2.45GHz for 30 minutes, generate mixed gas product;

(3) get 100g catalyst B (iron-nickel alloy, the mass ratio of iron and nickel is 4:1) and load it in microwave reactor (2), set microwave power to be 3000W, frequency 2.45GHz, open microwave reactor ( 1) at the same time, the microwave reactor (2) is opened, and the loaded catalyst B is preheated;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 3000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 10;

Table 10: Gas Product Analysis

(5) The hydrogen-containing gas product obtained in step (4) is scrubbed and subjected to pressure swing adsorption (PSA) treatment, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Example 10

In this embodiment, the domestic waste sample C is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample C, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physico-mechanical mixing of the dried and pulverized household garbage sample with 100 g of catalyst A (iron metal catalyst supported by silicon carbide, the mass ratio of silicon carbide and iron is 5:1), put into a microwave reactor ( 1) in, carry out purging for 10 minutes under nitrogen conditions (100ml/min), microwave reaction under the condition of power 3000W, frequency 2.45GHz for 30 minutes, generate mixed gas product;

(3) get 100g catalyst B (iron-nickel alloy, the mass ratio of iron and nickel is 4:1) and load it in microwave reactor (2), set microwave power to be 3000W, frequency 2.45GHz, open microwave reactor ( 1), the microwave reactor (2) is opened at the same time, and the loaded catalyst B is preheated;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 3000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 11;

Table 11: Gas Product Analysis

H₂ 58.9% CH₄ 1.9% C₂₊ 1% CO 29.9% CO₂ 8.3%

(5) The hydrogen-containing gas product obtained in step (4) is scrubbed and subjected to pressure swing adsorption (PSA) treatment, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Example 11

In this example, the domestic waste sample B is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample B, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physically and mechanically mix the dried and pulverized household garbage sample with 100 g of catalyst A (iron-nickel alloy, the mass ratio of iron and nickel is 4:1), put it into the microwave reactor (1), and put it into the microwave reactor (1). Purging under the condition (100ml/min) for 10 minutes, microwave reaction under the condition of power 3000W and frequency 2.45GHz for 30 minutes to generate mixed gas product;

(3) get 50g catalyst B (same catalyst A, iron-nickel alloy, the mass ratio of iron and nickel is 4:1) and load it in microwave reactor (2), set microwave power to be 4000W, frequency 2.45GHz, turn on The microwave reactor (2) is opened at the same time as the microwave reactor (1), and the loaded catalyst B is preheated;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 4000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 12;

Table 12: Gas Product Analysis

H₂ 66.7% CH₄ 2.1% C₂₊ 1.1% CO 17.4% CO₂ 12.7%

(5) The hydrogen-containing gas product obtained in step (4) is subjected to pressure swing adsorption (PSA) treatment, and after separation and purification, hydrogen gas with a purity of 99.9% is collected.

Example 12

In this example, the domestic waste sample B is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample B, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physico-mechanical mixing of the dried and pulverized household garbage sample with 100 g of catalyst A (iron metal catalyst supported by silicon carbide, the mass ratio of silicon carbide and iron is 5:1), put into a microwave reactor ( 1) in, carry out purging for 10 minutes under nitrogen conditions (100ml/min), microwave reaction under the condition of power 3000W, frequency 2.45GHz for 30 minutes, generate mixed gas product;

(3) get 50g catalyst B (same as catalyst A, it is the iron metal catalyst supported by silicon carbide, the mass ratio of silicon carbide and iron is 5:1) and load it in microwave reactor (2), set microwave power to be 4000W , frequency 2.45GHz, open microwave reactor (2) while opening microwave reactor (1), carry out preheating to the catalyst B of loading;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 4000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 13;

Table 13: Gas Product Analysis

H₂ 64.3% CH₄ 3.3% C₂₊ 1% CO 21.6% CO₂ 9.8%

(5) The hydrogen-containing gas product obtained in step (4) is scrubbed and subjected to pressure swing adsorption (PSA) treatment, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Example 13

In this example, the domestic waste sample B is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample B, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physico-mechanical mixing of the dried and pulverized household garbage sample with 100 g of catalyst A (iron metal catalyst supported by silicon carbide, the mass ratio of silicon carbide and iron is 5:1), put into a microwave reactor ( 1) in, carry out purging for 10 minutes under nitrogen conditions (100ml/min), microwave reaction under the condition of power 3000W, frequency 2.45GHz for 30 minutes, generate mixed gas product;

(3) Take 100g of catalyst B (silicon carbide) and load it in the microwave reactor (2), set the microwave power to 4000W and the frequency to 2.45GHz, and open the microwave reactor (1) at the same time as the microwave reactor (2) , preheating the loaded catalyst B;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 4000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 14;

Table 14: Gas Product Analysis

H₂ 41.2% CH₄ 18.9% C₂₊ 9.1% CO 21.1% CO₂ 9.7%

(5) The hydrogen-containing gas product obtained in step (4) is scrubbed and subjected to pressure swing adsorption (PSA) treatment, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

Example 14

In this example, the domestic waste sample B is used as the raw material to carry out the hydrogen production reaction, and the process flow is shown in Figure 1, which specifically includes the following steps:

(1) Take 300g of household waste sample B, set a temperature of 110°C and a heating rate of 20°C/min in a microwave drying reactor, carry out drying treatment for 1 hour to reduce the water content to below 10%, and then pulverize;

(2) Fully physically and mechanically mix the dried and pulverized household garbage sample with 100 g of catalyst A (activated carbon), put it into the microwave reactor (1), and carry out purging for 10 minutes under nitrogen conditions (100 ml/min). , microwave reaction under the condition of power 3000W and frequency 2.45GHz for 30 minutes to generate mixed gas product;

(3) get 100g catalyst B (activated carbon) and load it in microwave reactor (2), set microwave power to be 4000W, frequency 2.45GHz, open microwave reactor (2) while opening microwave reactor (1), Preheat the loaded catalyst B;

(4) pass the mixed gas product obtained in step (2) into the microwave reactor (2), microwave reaction under the condition of power 4000W, frequency 2.45GHz for 30 minutes, generate hydrogen-containing gas product, collect and sample analysis after gas washing , the results are shown in Table 15;

Table 15: Gas Product Analysis

H₂ 31.8% CH₄ 15.1% C₂₊ 22.4% CO 12.6% CO₂ 18.1%

(5) The hydrogen-containing gas product obtained in step (4) is scrubbed and subjected to pressure swing adsorption (PSA) treatment, and after separation and purification, the hydrogen with a purity of 99.9% is collected.

In the above embodiment, domestic waste is used as the treatment sample, and the in-situ pyrolysis-catalytic dehydrogenation of the catalyst is realized through the interaction between the catalyst and the microwave, and high-purity hydrogen can be prepared. The hydrogen yield is high, and the reaction conditions are mild. The production of harmful substances is reduced in the process.

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

Although the present invention has been described in detail above with general description, specific embodiments and tests, some modifications or improvements can be made on the basis of the present invention, which is obvious to those skilled in the art . Therefore, these modifications or improvements made without departing from the spirit of the present invention fall within the scope of the claimed protection of the present invention.

Claims (10)

1. The method for producing hydrogen by using household garbage is characterized in that the household garbage is used as a raw material and subjected to microwave catalytic treatment to prepare hydrogen-containing gas; the catalyst adopted by the microwave catalysis is selected from a carbon material, a transition metal material or a transition metal material taking the carbon material as a carrier;

the household garbage comprises humus, metal articles, plastic articles, paper articles, glass, leather products, cloth articles, ash and soil residues 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 residues content is 0-30 wt%, and the wood article content is 0-30 wt%;

and/or drying the household garbage before microwave catalytic treatment.

2. The method according to claim 1, wherein the household garbage contains 15 to 35wt% of humus, 0 to 7wt% of metal articles, 10 to 35wt% of plastic articles, 15 to 28wt% of paper articles, 0 to 8wt% of glass articles, 0 to 5wt% of leather articles, 0 to 4wt% of cloth articles, 5 to 16wt% of ash and soil residues, and 0 to 20wt% of wood articles;

preferably, the domestic garbage contains 15-30 wt% of humus, 0.5-6 wt% of metal articles, 25-35 wt% of plastic articles, 15-28 wt% of paper articles, 5-8 wt% of glass, 0-1.5 wt% of leather articles, 0-4 wt% of cloth articles, 5-16 wt% of ash and soil residues and 0-10 wt% of wood articles;

more preferably, the domestic garbage contains 15-20 wt% of humus, 0.5-1.5 wt% of metal articles, 28-32 wt% of plastic articles, 25-28 wt% of paper articles, 5-7 wt% of glass articles, 1.0-1.5 wt% of leather articles, 3-4 wt% of cloth articles, 5-6 wt% of ash and soil residues and 8-10 wt% of wood articles.

3. The method according to claim 1 or 2, characterized in that the carbon material is selected from carbon black, activated carbon and silicon carbide;

and/or the transition metal material is selected from iron-nickel series metal materials, preferably selected from metallic iron, metallic nickel, ferric oxide, ferroferric oxide, nickel oxide, iron-nickel alloy and mixed iron-nickel oxide;

and/or in the transition metal material taking the carbon material as the carrier, the mixing mass ratio of the carbon material carrier and the transition metal material is (1-5): 1.

4. The method according to any one of claims 1 to 3, wherein the microwave catalytic treatment uses a microwave power of 1000W to 6000W and a frequency of 0.3 GHz to 3GHz; preferably, the microwave power adopted by the microwave catalytic treatment is 2000W-4000W, and the frequency of the microwave treatment is 2.45GHz or 915MHz, and more preferably 2.45GHz.

5. The method according to any one of claims 1 to 4, wherein the microwave catalytic treatment is carried out in an inert environment at standard atmospheric pressure with an oxygen content of less than 5000 ppm; and/or the treatment time is 30 to 60 minutes.

6. The process according to any one of claims 1 to 5, characterized in that it comprises two stages of microwave catalytic treatment carried out in succession; wherein:

the first stage of microwave catalytic treatment is to perform primary microwave treatment on the domestic garbage under the action of a catalyst A to generate mixed gas;

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

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

7. The method according to claim 6, wherein the catalyst A is a carbon material, an iron-nickel alloy or a metallic iron catalyst using a carbon material as a carrier; and/or the catalyst B is a carbon material, ferric oxide, an iron-nickel alloy or metallic iron catalyst taking the carbon material as a carrier;

the carbon material is preferably activated carbon or silicon carbide;

preferably, the catalyst A is activated carbon-supported iron-nickel alloy, activated carbon, iron-nickel alloy or silicon carbide-supported metallic iron; and/or the catalyst B is ferric oxide, activated carbon-supported iron-nickel alloy, iron-nickel alloy or silicon carbide-supported metallic iron;

further preferably, the catalyst A and the catalyst B are both iron-nickel alloy or activated carbon supported iron-nickel alloy; and/or the mass ratio of iron to nickel in the iron-nickel alloy is (2-5): 1.

8. the method according to claim 6 or 7, wherein the mass ratio of the household garbage to the catalyst A adopted in the method is (1-10) 1; and/or the mass ratio of the catalyst A to the catalyst B adopted in the method is (1-2): (1-2).

9. The method according to any one of claims 6 to 8, wherein the power of the primary microwave treatment is 2000W to 3000W; the power of the secondary microwave treatment is 2000W-4000W, and is the same as or different from the power of the primary microwave treatment;

and/or the frequency of the primary microwave treatment and the secondary microwave treatment is 2.45GHz.

10. The method according to any one of claims 6 to 9, wherein the first stage microwave catalytic treatment and the second stage microwave catalytic treatment employ a first microwave reactor and a second microwave reactor connected in series; preferably, the catalyst B in the second microwave reactor is preheated during the first stage of microwave catalytic treatment.

Images