Membrane Hydrogen Generation Assembly With CO2 Byproduct Reuse
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Solution Overview
Problem
Existing hydrogen generation assemblies face challenges in efficiently purifying hydrogen gas streams to meet the requirements of energy production applications, such as electrochemical fuel cells, due to the presence of impurities like carbon dioxide and other gases.
Innovation Solution
The method involves a hydrogen generation assembly that includes a fuel processing assembly where a carbon-containing feedstock is heated to produce an output stream containing hydrogen gas and carbon dioxide. This output stream is then processed in a purification region using hydrogen-selective membranes to separate a product hydrogen stream with high hydrogen concentration and a byproduct stream with high carbon dioxide concentration, followed by a gas removal assembly that separates carbon dioxide from the byproduct stream to produce a fuel stream for reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hydrogen-selective membranes are used to purify the mixed gas stream, then hydrogen purity is improved, but device complexity increases
Solution Approach 1:
The hydrogen-selective membranes are nested within a pressure vessel, creating a compact integrated purification system. The membranes are contained inside the pressure vessel which is part of the existing hydrogen generation assembly, allowing purification functionality to be nested within the structural framework already present in the system.
Solution Approach 2:
The pressure vessel serves multiple functions: it contains the hydrogen-selective membranes for purification, maintains system pressure, and provides structural support. This multi-functionality reduces the need for separate dedicated components, thereby reducing overall device complexity while maintaining high hydrogen purity through membrane separation.
2Productivity
If the hydrogen generation assembly operates at elevated temperatures, then hydrogen production efficiency is improved, but energy consumption increases
Solution Approach 1:
The byproduct stream containing carbon dioxide and other gases, which would normally be wasted, is redirected to the heating assembly where it combusts to provide heat for the hydrogen-producing region. This converts the harmful waste gases into a beneficial heat source, maintaining the elevated temperatures needed for high hydrogen production efficiency while reducing external energy consumption.
Solution Approach 2:
The system implements a feedback loop where the byproduct stream from membrane purification is fed back to the heating assembly, which in turn provides heat to the hydrogen-producing region. This closed-loop thermal feedback system automatically maintains optimal operating temperatures using the system's own byproducts, reducing the need for external energy input while sustaining high productivity.
3Object-generated harmful factors
If carbon dioxide is removed from the byproduct stream, then environmental impact is reduced, but loss of substance increases
Solution Approach 1:
Rather than discarding carbon dioxide as waste, the system utilizes it as fuel in the heating assembly. The carbon dioxide-containing byproduct stream combusts to generate heat, converting the harmful greenhouse gas into a beneficial energy source. This eliminates the need to remove carbon dioxide for environmental reasons while preventing any loss of substance, as all byproduct materials are put to productive use.
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 effectively increases the hydrogen purity of the product stream, reduces carbon dioxide emissions, and provides a fuel stream that can be reused to maintain the hydrogen-producing region at optimal temperatures, enhancing the overall efficiency and sustainability of the hydrogen generation process.
Implementation Method 1
Hydrogen purification using one or more hydrogen-selective membranes is a pressure driven separation process in which the one or more hydrogen-selective membranes are contained in a pressure vessel. The mixed gas stream contacts the mixed gas surface of the membrane(s), and the product stream is formed from at least a portion of the mixed gas stream that permeates through the membrane(s).
Implementation Method 2
The heating assembly is configured to receive at least one fuel stream and to combust the at least one fuel stream to provide a heated combustion stream for heating the hydrogen-producing region to a temperature sufficient to effectively generate hydrogen gas.
Implementation Method 3
The hydrogen generation assembly may generate hydrogen gas via any suitable mechanism(s), such as steam reforming, autothermal reforming, pyrolysis, and/or catalytic partial oxidation.
Implementation Method 4
The hydrogen generation assembly may generate hydrogen gas via any suitable mechanism(s), such as steam reforming, autothermal reforming, pyrolysis, and/or catalytic partial oxidation.
Data Source
AI summary
Hydrogen generation assemblies and methods are disclosed. In one embodiment, the method includes receiving a feed stream in a fuel processing assembly, and heating, via one or more burners, a hydrogen generating region of the fuel processing assembly to at least a minimum hydrogen-producing temperature. The method additionally includes generating an output stream in the heated hydrogen generating region of the fuel processing assembly from the received feed stream, and generating a product hydrogen stream and a byproduct stream in a purification region of the fuel processing assembly from the output stream. The method further includes separating at least a portion of the carbon dioxide gas from the byproduct stream to generate a fuel stream having a carbon dioxide concentration less than the byproduct stream, and feeding the fuel stream to the one or more burners.