阅读说明：本技术 沼液水相重整制取氢气的方法 (Method for preparing hydrogen by reforming biogas slurry water phase ) 是由 颜蓓蓓 毛雨柔 李婉晴 陈冠益 陶俊宇 于 2019-10-16 设计创作，主要内容包括：一种沼液水相重整制取氢气的方法,该方法包括在沼液中加入催化剂后在加压条件下反应后冷却收集气体。本发明为沼液的处理与利用提供了新途径,所述水相重整制取氢气技术省略了原料的汽化步骤,在相对温和的反应条件下,直接一步反应制取氢气,同时使高温条件下容易发生的副反应影响最小化,将沼液通过水相重整技术制取氢气,操作便捷、设备简单,制取的氢气可就地用于供热或发电。(A method for preparing hydrogen by reforming a biogas slurry water phase comprises the steps of adding a catalyst into biogas slurry, reacting under a pressurized condition, cooling and collecting gas. The invention provides a new way for the treatment and utilization of biogas slurry, the technology for preparing hydrogen by aqueous phase reforming omits the vaporization step of raw materials, hydrogen is prepared by one-step reaction under relatively mild reaction conditions, meanwhile, the side reaction influence which is easy to occur under high temperature conditions is minimized, the biogas slurry is prepared into hydrogen by the aqueous phase reforming technology, the operation is convenient, the equipment is simple, and the prepared hydrogen can be used for heat supply or power generation on site.)

1. A method for preparing hydrogen by reforming a biogas slurry water phase comprises the steps of adding a catalyst into biogas slurry, reacting under a pressurization condition, cooling and collecting gas.

2. The method for producing hydrogen according to claim 1,

the concentration of the catalyst is 2-5 g/L.

3. The method for producing hydrogen according to claim 1,

the reaction pressure of the reaction is 1.5-5.0MPa, preferably 2.5-3.0 MPa;

the reaction temperature is 150-250 ℃, and preferably 200-250 ℃;

the stirring speed is 200-300r/min, preferably 200-250 r/min;

the reaction time is 2.5-3h, preferably 3 h.

4. The method for producing hydrogen according to claim 1,

the preparation method of the catalyst comprises the following steps: preparing a supported nickel-based catalyst by adopting an isometric impregnation method, and reducing the supported nickel-based catalyst in a hydrogen atmosphere to obtain a black powdery solid, namely the catalyst.

5. The method for producing hydrogen according to claim 4,

the preparation method of the catalyst comprises the following steps:

1) preparing a supported nickel-based catalyst by an isometric impregnation method: adding nickel nitrate into distilled water, stirring for 15-25min, adding a catalyst carrier, stirring for 15-25min, drying at 85-95 ℃, and taking out to obtain a solid A;

2) hydrogen reduction: in the atmosphere of hydrogen, reducing the solid A obtained in the step 1) at 550-650 ℃ for 2.5-3.5h to obtain a black powdery solid B, wherein the solid B is the catalyst.

6. The method for producing hydrogen according to claim 1,

the Ni content in the supported nickel-based catalyst is 15-20 wt%.

7. The method for producing hydrogen according to claim 1,

the catalyst carrier is CeO₂Support or Al₂O₃A carrier;

the CeO₂The preparation method of the carrier comprises the following steps: baking cerium nitrate at the temperature of 550-650 ℃ for 1.5-2.5h to obtain CeO₂And (3) a carrier.

8. The method for producing hydrogen according to claim 1,

the biogas slurry comprises liquid-phase by-products obtained by anaerobic fermentation of livestock and poultry manure, crop straws, municipal refuse and excess sludge.

9. The method for producing hydrogen according to claim 1,

the step of cooling in the cooling collection gas is realized by adopting an ice bath cooling method.

10. The method for producing hydrogen according to claim 1,

adding the biogas slurry and a catalyst into a reactor for reaction;

the reactor is a micro reaction kettle with a heating, pressurizing and stirring device.

Technical Field

The invention relates to the field of resource utilization of byproducts in an energy utilization process and the field of environment, and in particular relates to a method for preparing hydrogen by biogas slurry aqueous phase reforming and application of the method.

Background

With the rapid development of agriculture in China, the annual yield of agricultural wastes is increasing day by day, and only the annual yield of livestock and poultry manure exceeds 38 hundred million tons. But the comprehensive utilization rate is less than 60 percent, and the phenomenon of messy stacking is excessive, thereby causing serious environmental pollution. The anaerobic fermentation technology is an important means for treating agricultural wastes, and can convert the agricultural wastes into methane for realizing resource utilization. In the year of 2017, the method has the advantages that,the methane yield of anaerobic fermentation of agricultural wastes in China reaches 1.58 multiplied by 10¹⁰m³But the yield of the corresponding byproduct biogas slurry and residue is huge. The biogas slurry is a liquid residue with a solid content of less than 10% in the anaerobic fermentation process, contains rich nitrogen, phosphorus, potassium, iron, copper, manganese and other trace elements, is often used as fertilizer or feed, and has application safety influenced by the harmful substances such as heavy metals, pathogenic bacteria and the like. According to the annual output of the biogas in China, the annual output is estimated to be about 4.04 multiplied by 10¹⁰m³Biogas slurry is generated, wherein more than 83.3 percent of biogas slurry is directly discharged without being treated, and a large amount of polycyclic aromatic hydrocarbons, phenolic compounds, phthalic acid esters and other organic matters exist in the biogas slurry, so that the biogas slurry is an ideal way for improving the comprehensive utilization rate of the biogas slurry and relieving the energy crisis if the organic matters can be converted into fuel gas for utilization.

The existing technology for researching hydrogen production from biogas slurry mainly comprises a steam reforming hydrogen production technology. However, in the method, the hydrogen production technology by steam reforming firstly vaporizes the biogas slurry under the conditions of high temperature and normal pressure (500-700 ℃), and then reforms the biogas slurry to produce hydrogen, and side reactions are easy to occur at high temperature. The method has the advantages of higher requirement on process conditions, more complex operation, less harmful gas in the reaction product, higher production cost and difficult industrial production and application. Therefore, it is necessary to research the direct one-step reaction to prepare hydrogen under relatively mild reaction conditions, and reduce the side reactions which are easy to occur under high temperature conditions.

Disclosure of Invention

In view of the above, one of the main objectives of the present invention is to provide a method for producing hydrogen by aqueous phase reforming of biogas slurry and the use thereof, so as to at least partially solve at least one of the above technical problems.

In order to achieve the purpose, the invention provides a method for preparing hydrogen by biogas slurry aqueous phase reforming, which comprises the steps of adding a catalyst into biogas slurry, reacting under a pressurized condition, cooling and collecting gas.

In some embodiments of the invention, the concentration of the catalyst is 2 to 5 g/L.

In some embodiments of the invention, the reaction pressure of the reaction is 1.5 to 5.0MPa, preferably 2.5 to 3.0 MPa;

the reaction temperature is 150-250 ℃, and preferably 200-250 ℃;

the stirring speed is 200-300r/min, preferably 200-250 r/min;

the reaction time is 2.5-3h, preferably 3 h.

In some embodiments of the invention, the catalyst is prepared by: preparing a supported nickel-based catalyst by adopting an isometric impregnation method, and reducing the supported nickel-based catalyst in a hydrogen atmosphere to obtain a black powdery solid, namely the catalyst.

Based on the technical scheme, compared with the prior art, the method for preparing hydrogen by reforming the biogas slurry in the water phase has at least one of the following advantages:

(1) the method for preparing hydrogen through biogas slurry is provided, a new way is provided for the treatment and utilization of biogas slurry, the process of preparing hydrogen from renewable biogas slurry is realized, and the proportion of hydrogen gas in the detectable components is more than 35% under the optimal implementation condition;

(2) the hydrogen prepared by the method can enrich the forms of the gas in the methane industrial chain and improve the value of the gas product;

(3) the technology for preparing hydrogen by aqueous phase reforming omits the vaporization step of raw materials, directly prepares hydrogen by one-step reaction under relatively mild reaction conditions (150 ℃ and 250 ℃, 1.5-5.0MPa), and simultaneously minimizes the side reaction influence which is easy to occur under high temperature conditions;

(4) the biogas slurry is used for preparing hydrogen through a water phase reforming technology, the operation is convenient and fast, the equipment is simple, and the prepared hydrogen can be used for heat supply or power generation on site.

Drawings

Fig. 1 is a flow chart of a method for preparing hydrogen by biogas slurry aqueous phase reforming according to an embodiment of the invention.

Detailed Description

In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.

The invention discloses a method for preparing hydrogen by reforming a biogas slurry water phase, which comprises the steps of adding a catalyst into biogas slurry, reacting under a pressurized condition, cooling and collecting gas.

Wherein the concentration of the catalyst is 2-5 g/L.

Wherein the reaction pressure of the reaction is 1.5 to 5.0MPa, for example, 2.5 to 3.0 MPa; the reaction temperature is 150-250 ℃, for example, 200-250 ℃; the stirring speed is 200-300r/min, such as 200-250 r/min; the reaction time is 2.5 to 3 hours, for example 3 hours.

The preparation method of the catalyst comprises the following steps: preparing a supported nickel-based catalyst by adopting an isometric impregnation method, and reducing the supported nickel-based catalyst in a hydrogen atmosphere to obtain a black powdery solid, namely the catalyst.

The preparation method of the catalyst comprises the following steps:

1) preparing a supported nickel-based catalyst by an isometric impregnation method: adding nickel nitrate into distilled water, stirring for 15-25min, adding a catalyst carrier, stirring for 15-25min, drying at 85-95 ℃, and taking out to obtain a solid A;

2) hydrogen reduction: reducing the isomer A obtained in the step 1) at the temperature of 550-650 ℃ for 2.5-3.5h in a hydrogen atmosphere to obtain black powdery solid B, wherein the solid B is the catalyst.

Wherein the Ni content in the supported nickel-based catalyst is 15-20 wt%.

Wherein the catalyst carrier is CeO₂Support or Al₂O₃And (3) a carrier.

Wherein the CeO₂The preparation method of the carrier comprises the following steps: baking cerium nitrate at the temperature of 550-650 ℃ for 1.5-2.5h to obtain CeO₂And (3) a carrier.

Wherein the biogas slurry comprises liquid-phase by-products obtained by anaerobic fermentation of livestock and poultry manure, crop straws, municipal refuse and excess sludge.

Wherein, the step of cooling in the cooling collecting gas is realized by adopting an ice bath cooling method.

Wherein, the biogas slurry and the catalyst are added into a reactor for reaction.

Wherein, the reactor is a micro reaction kettle with a heating, pressurizing and stirring device.

The invention provides a method for preparing hydrogen by reforming a biogas slurry water phase, which solves the problems of high yield and single treatment mode of agricultural waste and aquaculture waste at present. Putting a certain amount of biogas slurry into a reaction kettle, adding a catalyst and a magnetic rotor, and sealing the reaction kettle; introducing nitrogen to discharge air and adjusting pressure, temperature and rotating speed; after reacting for a period of time, the reaction kettle is placed in an ice bath to be cooled to room temperature, and the non-condensable gas obtained from the gas outlet is a gas-phase product containing hydrogen.

In an exemplary embodiment of the invention, a method for preparing hydrogen by reforming a biogas slurry in an aqueous phase comprises the following steps:

(1) placing 100mL of biogas slurry in a miniature reaction kettle, adding a catalyst and a magnetic rotor, and sealing the reaction kettle;

(2) introducing nitrogen to discharge air, adjusting the pressure to 2.5-3.0MPa, the reaction temperature to 200-;

(3) stopping heating and stirring, placing the reaction kettle in an ice bath to cool to room temperature, and obtaining non-condensable gas from a gas outlet as a gas-phase product containing hydrogen.

The biogas slurry comprises liquid-phase by-products obtained by anaerobic fermentation of livestock and poultry manure, crop straws, municipal waste and excess sludge. Preferably, the carrier of the supported nickel-based catalyst is CeO₂Or Al₂O₃。

The loading range of the active component Ni in the supported nickel-based catalyst is 15-20 wt%, if the loading is too low, the number of metal active bits is insufficient, the reaction rate is low, and if the loading is too high, metal agglomeration is caused, and the catalytic activity is low; the adding amount of the catalyst is 2-5g/L, if the adding amount is too low, the catalyst effect is not enough, and if the adding amount is too high, the cost is increased.

The reactor is a micro reaction kettle with a heating, pressurizing and stirring device.

The biogas slurry adopted by the invention comprises but is not limited to a liquid-phase byproduct obtained by anaerobic fermentation of livestock and poultry manure.

The catalyst carrier used in the present invention may be Al₂O₃And CeO₂Etc., in principle, any carrier having characteristics of high specific surface area, high thermal stability, etc. may be used as the catalyst carrier employed in the present invention, such as molecular sieves, activated carbon carriers, etc.

In the invention, the reaction pressure is within the range of 2.5-3.0MPa, the pressure is lower than 2.5MPa, the saturated vapor pressure of the biogas slurry is easily reached to gasify the raw materials, the side reactions are increased when the pressure is higher than 3.0MPa, and H is not facilitated₂And (4) generating.

The catalytic reaction temperature is 200-250 ℃, the organic nitrogen in the biogas slurry is easy to react with water to generate ammonia gas at the temperature lower than 200 ℃, the water vapor shift reaction at the temperature higher than 250 ℃ is enhanced, the hydrogen content and selectivity are reduced, and CO is generated₂The content is increased and the energy consumption is improved.

The technical solution of the present invention is further illustrated by the following specific embodiments in conjunction with the accompanying drawings. It should be noted that the following specific examples are given by way of illustration only and the scope of the present invention is not limited thereto.

The chemicals and raw materials used in the following examples were either commercially available or self-prepared by a known preparation method.

As shown in fig. 1, a method for preparing hydrogen by aqueous phase reforming of biogas slurry comprises the following steps:

(1) preparing a catalyst:

1) preparing a supported nickel-based catalyst by adopting an isometric impregnation method: adding nickel nitrate into distilled water, stirring for 15-25min, adding a catalyst carrier, stirring for 15-25min, drying at 85-95 ℃, and taking out to obtain a solid A;

2) hydrogen reduction: in the atmosphere of hydrogen, reducing the solid A obtained in the step 1) at 550-650 ℃ for 2.5-3.5h to obtain a black powdery solid B, wherein the solid B is the catalyst;

wherein the Ni content is 15-20 wt%, and the carrier can be CeO₂And Al₂O₃And the like, and obtaining the black powdery catalyst after reduction in a hydrogen atmosphere.

(2) And (3) catalytic reaction: adding the catalyst and the magnetic rotor into the biogas slurry and the catalyst in the step (1), and sealing the reaction kettle; introducing nitrogen to discharge air, adjusting the pressure to 2.5-3.0MPa, the reaction temperature to 200-; the biogas slurry comprises liquid-phase by-products obtained by anaerobic fermentation of livestock and poultry manure, crop straws, municipal refuse and excess sludge.

(3) And (3) collecting a product: stopping heating and stirring, placing the reaction kettle in an ice bath to cool to room temperature, and obtaining non-condensable gas from a gas outlet as a gas-phase product containing hydrogen.