Process for preparing hydrogen gas and nanometer carbon by catalyzing and cracking methane at low temperature

A low-temperature catalysis, nano-carbon technology, applied in chemical instruments and methods, hydrogen, inorganic chemistry, etc., can solve the problems of unreachable methane conversion rate, decreased specific surface area, and inability to carry out the process, and achieves improved operational safety and production. Cost and operation and maintenance reduction, the effect of increasing the operating life

Active Publication Date: 2009-01-07
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the severe sintering of the nano-metal catalyst at 800°C, the specific surface area is greatly reduced, and its activity is greatly reduced. The catalyst will be deactivated in a very short time (several seconds), and the process cannot be carried out.
[0005] How

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  • Process for preparing hydrogen gas and nanometer carbon by catalyzing and cracking methane at low temperature
  • Process for preparing hydrogen gas and nanometer carbon by catalyzing and cracking methane at low temperature
  • Process for preparing hydrogen gas and nanometer carbon by catalyzing and cracking methane at low temperature

Examples

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Embodiment 1

[0032] A method for preparing hydrogen and nano-carbon by catalytic cracking methane at a low temperature, the method comprising the following steps:

[0033] (1) Use nano-metal catalysts containing iron, molybdenum, and aluminum to control the average grain size of the nano-metals to 10nm and the specific surface area to be 300m 2 / g, the bulk density is 400kg / m 3 , the Mohs hardness is 6.8, the particle size range is 20-150 microns, and the average particle size is 75 microns. Put it into a fluidized bed reactor, heat up to 500°C, and reduce the catalyst with high-purity nitrogen containing 5% hydrogen for about 3 hours; then heat up to 650°C; (2) feed 51% methane, 49% acetylene Mixed gas, the control catalyst space velocity is 250 liters of hydrocarbons / gram catalyst / h, and operating pressure is 0.15MPa (absolute pressure) to react, with figure 1 The model shown generates hydrogen gas with nanocarbon products. Within 2 hours, the conversion rate of acetylene is 100%, the...

Embodiment 2

[0035]A method for preparing hydrogen and nano-carbon by catalytic cracking methane at a low temperature, the method comprises the following steps: (1) using a nano-metal catalyst containing nickel and copper supported on aluminum oxide, controlling the average grain size of the nano-metal to 50nm, the specific surface area is 200m 2 / g, the bulk density is 650kg / m 3 , the Mohs hardness is 7.3, the particle size range is 30-250 microns, and the average particle size is 175 microns. Put it into a fluidized bed reactor, raise the temperature to 400°C, reduce the catalyst with high-purity nitrogen containing 50% hydrogen for about 7 hours, and then raise the temperature to 450°C; (2) feed 81% methane, 19% ethylene Mixed gas, the catalyst space velocity is controlled to be 450 liters of hydrocarbons / g catalyst / h, and the operating pressure is 0.13 MPa (absolute pressure) for reaction. by figure 1 The model shown generates hydrogen gas with nanocarbon products. The conversion r...

Embodiment 3

[0037] A method for preparing hydrogen and nano-carbon by catalytic cracking methane at a low temperature, the method comprises the following steps: (1) loading iron and chromium nano-metal on the oxidized and truncated figure 1 On the carbon product in the catalyst, it constitutes a catalyst. Control the grain size of its nanometer metal to be 10nm on average, and the specific surface area is 350m 2 / g, the bulk density is 450kg / m 3 , the Mohs hardness is 6.3, the particle size range is 30-200 microns, and the average particle size is 105 microns. Put it into a fluidized bed reactor, raise the temperature to 500°C, reduce the catalyst with high-purity nitrogen containing 15% hydrogen for about 0.5 hours, and then raise the temperature to 650°C; (2) feed 25% methane, 75% propylene Mixed gas, the control catalyst space velocity is 150 liters of hydrocarbons / gram catalyst / h, and operating pressure is 0.11MPa (absolute pressure) to react, with figure 1 The model shown generate...

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Abstract

A method for preparing hydrogen and nano carbon through the catalytic pyrolysis of methane at lower temperature belongs to the technical field of petroleum and natural gas chemical production. The method comprises the steps of putting a catalyst in a reactor, heating to 400-700 DEG C jointly, introducing hydrogen or CO into conduct catalyst reduction, and keeping the temperature and the reducing atmosphere; switching the gas to a hydrocarbon gas in heat release in pyrolysis, the volume ratio of the hydrocarbon gas to methane is 1:9 to 9:1; introducing a feed gas, methane, into the reactor at the temperature of 400-700 DEG C, under the absolute pressure of 0.05 to 0.2 MPa, and at the catalyst airspeed of 100-100 liter (hydro carbon)/g (catalyst)/hour; preparing and obtaining hydrogen when the feed gas passes through the bed layer of the catalyst; and depositing carbon on the catalyst. The catalyst is a nano metallic catalyst. The method has the advantages of low operation temperature, prolonged service life of the catalyst, high conversion rate, continuous operations in the forms of various reactors, reduced production cost, and high purity and controllable appearance of carbon products.

Description

technical field [0001] The invention discloses a method for preparing hydrogen and nano-carbon by catalytically cracking methane at a low temperature, belonging to the technical field of petroleum and natural gas chemical production. Background technique [0002] Methane is the main component of natural gas, and it is one of the world's three major fossil energy sources along with petroleum and coal. In chemical production, methane is the most important synthesis gas (CO / H 2 ) or hydrogen feedstock. The main preparation methods include steam reforming of methane, partial oxidation and direct catalytic cracking in an oxygen-free environment. Among them, direct catalytic cracking, because no carbon oxides are produced, and the purity of hydrogen is high, it can be used as a raw material for proton membrane fuel cells. Under the action of electrodes with oxygen, chemical energy is converted into electrical energy, and the exhaust gas is water without any harmful effects. Env...

Claims

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Application Information

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IPC IPC(8): C01B3/26C01B31/02
Inventor 骞伟中魏飞魏彤黄河孙玉建田涛李琰汪展文金涌
Owner TSINGHUA UNIV
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