阅读说明：本技术 一种以活性炭为催化剂催化甲烷裂解制氢的方法 (Method for preparing hydrogen by catalyzing methane cracking with activated carbon as catalyst ) 是由 刘方 宣国会 杨丽 于 2020-06-16 设计创作，主要内容包括：本发明公开了一种以活性炭为催化剂催化甲烷裂解制氢的方法,所述方法采用气固相催化反应固定床反应器,以甲烷为原料,添加微量硫化氢,以活性炭为催化剂,于900-950℃、常压下反应,得到产物氢气和碳,其中硫化氢的浓度为100ppm-300ppm。本发明在甲烷原料气中添加微量硫化氢,提高了活性炭催化甲烷裂解制氢的活性,延长了活性炭催化剂的失活时间,对提升活性炭催化甲烷裂解制氢的转化效率具有重要的工业应用价值。(The invention discloses a method for preparing hydrogen by catalyzing methane cracking by using activated carbon as a catalyst, which adopts a gas-solid phase catalytic reaction fixed bed reactor, takes methane as a raw material, adds trace hydrogen sulfide, takes the activated carbon as the catalyst, and reacts at the temperature of 900-950 ℃ under normal pressure to obtain products of hydrogen and carbon, wherein the concentration of the hydrogen sulfide is 100ppm-300 ppm. According to the invention, trace hydrogen sulfide is added into the methane raw material gas, so that the activity of the activated carbon for catalyzing the methane cracking for hydrogen production is improved, the inactivation time of the activated carbon catalyst is prolonged, and the method has an important industrial application value for improving the conversion efficiency of the activated carbon for catalyzing the methane cracking for hydrogen production.)

1. A method for preparing hydrogen by catalyzing methane cracking by using activated carbon as a catalyst adopts a gas-solid phase catalytic reaction fixed bed reactor, and is characterized in that methane is used as a raw material, a trace amount of hydrogen sulfide is added, the activated carbon is used as the catalyst, and the reaction is carried out at the temperature of 900-950 ℃ and under normal pressure to obtain products of hydrogen and carbon, wherein the concentration of the hydrogen sulfide is 100ppm-300 ppm.

2. The method for preparing hydrogen by catalytic cracking of methane by using activated carbon as a catalyst according to claim 1, wherein the space velocity of methane in the hydrogen preparation by catalytic cracking of methane is 20 ml/min-g.

3. The method for preparing hydrogen by cracking methane by using activated carbon as a catalyst according to claim 1, wherein the concentration of the hydrogen sulfide is 200 ppm.

4. The method for preparing hydrogen by cracking methane by using activated carbon as a catalyst according to claim 1, wherein the activated carbon is coconut shell activated carbon with a particle size of 8-16 meshes.

Technical Field

The invention relates to the technical field of hydrogen production by methane cracking, in particular to a method for producing hydrogen by catalyzing methane cracking by using activated carbon as a catalyst.

Background

The direct cracking of methane to produce hydrogen is one clean hydrogen producing process, and methane is decomposed into hydrogen and carbon at high temperature without producing CO₂The method is a transition process for connecting fossil fuel and renewable energy. The methane cracking reaction is an endothermic reaction to produce hydrogenThe energy to be consumed is 37.8kJ/mol, C-H in methane molecules is very stable, the cracking rate of non-catalytic methane cracking reaction is very low below 1000 ℃, and the reaction temperature can be greatly reduced and the hydrogen yield can be improved during catalytic cracking.

At present, the research of hydrogen production by methane cracking mainly focuses on the aspects of developing catalysts which are efficient and easy to obtain, low in price and strong in stability. The metal catalyst has high catalytic activity and good stability, but the metal catalyst can form carbon nanotubes (CNTs or CNFs) in the catalytic process, the carbon tubes push away metal particles with catalytic activity from the surface of a carrier, and the carbon deposition is usually removed by using steam in the regeneration process, so that the metal particles fall off, the catalyst structure is damaged, and the metal catalyst is difficult to regenerate. The carbon-based catalyst does not generate metal carbide in the process of catalyzing methane cracking, and carbon deposition generated on the surface can be removed by using high-temperature steam, so that the catalyst is regenerated; and the carbon material catalyst has low price, wide raw material source, high temperature resistance, sulfur resistance and other toxic impurities resistance. The activated carbon catalyst is one of the most common carbon-based catalysts, the initial catalytic activity of the activated carbon catalyst is high, but the activated carbon catalyst is quickly deactivated, and the catalytic efficiency is low after the activated carbon catalyst is deactivated, so that the popularization and the application of the activated carbon catalyst are influenced.

Disclosure of Invention

The invention aims to provide a method for preparing hydrogen by catalyzing methane cracking by using activated carbon as a catalyst, which can delay the inactivation process of the activated carbon catalyst and improve the catalytic efficiency.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a method for preparing hydrogen by catalyzing methane cracking by using activated carbon as a catalyst adopts a gas-solid phase catalytic reaction fixed bed reactor, uses methane as a raw material, adds a trace amount of hydrogen sulfide, uses the activated carbon as the catalyst, and reacts at the temperature of 900-.

Preferably, the space velocity of methane in the hydrogen production by catalytic cracking of methane is 20 ml/min-g.

Preferably, the concentration of hydrogen sulfide is 200 ppm.

Preferably, the activated carbon is coconut shell activated carbon, and the particle size is 8-16 meshes.

Compared with the prior art, the invention has the following beneficial effects:

1. according to the invention, ppm-level trace hydrogen sulfide gas is added into the feed gas, so that the activity of the activated carbon for catalyzing the methane cracking for hydrogen production is improved, the inactivation time of the activated carbon catalyst is prolonged, and the method has an important industrial application value for improving the conversion efficiency of the activated carbon for catalyzing the methane cracking for hydrogen production;

2. the method adopts the activated carbon as the catalyst, is cheap and easy to obtain, has low production cost and high economy, and the carbon deposit generated by the reaction does not need to be separated and can be directly used as the precursor of the carbon material to realize the recycling of the catalyst.

Drawings

FIG. 1 is a graph showing the conversion of catalytic methane cracking to produce hydrogen at 900 ℃ for examples 1-3 and comparative example 1;

FIG. 2 is a graph of the catalytic methane cracking hydrogen production conversion rate at 950 ℃ for examples 4-6 and comparative example 2;

FIG. 3a is a scanning electron micrograph of the morphology of the activated carbon catalyst surface prior to reaction in example 1;

FIG. 3b is a scanning electron micrograph of the morphology of the activated carbon catalyst surface after 10min of reaction in example 1;

FIG. 3c is a scanning electron micrograph of the morphology of the activated carbon catalyst surface after 10min of reaction in comparative example 1;

FIG. 3d is a scanning electron micrograph of the morphology of the activated carbon catalyst surface after 90min of reaction in example 1;

FIG. 3e is a scanning electron micrograph of the morphology of the activated carbon catalyst surface after 90min of reaction in comparative example 1.

Detailed Description

The invention is described in further detail below with reference to the figures and specific examples.