Hydrogen Extraction from Natural Gas with CO2 Recycling
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Solution Overview
Problem
Conventional hydrogen extraction methods from natural gas result in significant carbon dioxide emissions due to the production of CO2 during steam splitting and subsequent conversion stages, making them major contributors to environmental pollution.
Innovation Solution
A method involving catalytic splitting of hydrocarbons in a reformer using steam to produce hydrogen, carbon monoxide, and carbon dioxide, followed by conversion of carbon monoxide to carbon dioxide, which is then removed through gas scrubbing, and the use of a pressure swing adsorption system to separate hydrogen, with the waste gas being recycled as a fuel gas free of carbon, eliminating the need for carbon-containing fuels in reformer firing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional steam splitting and conversion methods are used to extract hydrogen from natural gas, then hydrogen production efficiency is improved, but carbon dioxide emissions increase significantly
Solution Approach 1:
The patent converts the harmful CO2 produced during steam splitting into a beneficial resource by recycling it to the reformer combustion chamber. The CO2 from the conversion stage is used as a fuel component, replacing external carbon-containing fuels and thereby reducing net CO2 emissions while maintaining the energy needed for hydrogen production
Solution Approach 2:
Instead of discarding the CO2 produced during the conversion stage as waste, the patent recovers and reuses it by feeding it back to the reformer combustion chamber. This recovery approach transforms a harmful emission into a useful fuel source, reducing the need for external carbon-containing fuels
2Productivity
If additional carbon-containing fuels are fired in the reformer combustion chamber to maintain energy supply, then hydrogen production continues, but carbon dioxide emissions increase further
Solution Approach 1:
The system becomes self-sufficient by using its own internally generated CO2 as fuel for the reformer combustion chamber. This eliminates the need to import external carbon-containing fuels, as the CO2 produced during hydrogen production is recycled and utilized to maintain the energy supply needed for continuous hydrogen production
Solution Approach 2:
The patent recovers the CO2 that would otherwise be discarded from the conversion stage and uses it as fuel in the reformer combustion chamber. This recovery process replaces the need for additional carbon-containing fuels, thereby maintaining hydrogen production continuity while reducing CO2 emissions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces carbon dioxide emissions by approximately 75% compared to conventional methods, utilizing proven technologies with minimal additional effort and expense, and allows for retrofitting existing hydrogen plants to achieve this reduction.
Implementation Method 1
Hydrocarbons contained in the gas are catalytically split into hydrogen, carbon monoxide, and carbon dioxide, in a reformer, by means of steam
Implementation Method 2
in a subsequent conversion stage, catalytic conversion of the carbon monoxides that have been formed to carbon dioxide and hydrogen takes place, with steam
Implementation Method 3
The carbon dioxide is removed from the converted gas stream by means of gas scrubbing
Implementation Method 4
the scrubbed, hydrogen-rich gas stream is subsequently separated into a product gas stream that consists of hydrogen, and a waste gas stream, in a pressure swing adsorption system
Implementation Method 5
The waste gas stream is passed to the reformer, together with hydrogen that is branched off from the gas stream behind the gas scrubber, as a fuel gas that is extensively free of carbon, and combusted there
Data Source
AI summary
The invention relates to a method for extracting hydrogen from a gas containing methane, especially natural gas. Hydrocarbons contained in the gas are catalytically broken down in a reformer (4) by steam in order to form hydrogen, carbon monoxide and carbon dioxide. Catalytic conversion of the obtained carbon monoxide with steam occurs in a downstream conversion step in order to form carbon monoxide and water. Carbon dioxide is removed from the converted gas flow (8) by gas washing (7), and the washed hydrogen-rich gas flow (10) is subsequently divided in a pressure-swing adsorption system (11) into a product gas flow (12) made of hydrogen and a waste gas flow (13). The waste gas flow (13) is introduced with hydrogen (14), which is separated from the gas flow (10) after gas washing, into a reformer (4) which is essentially a carbon-free combustible gas, and is combusted there. The invention also relates to a system for carrying out the method.