Electrically Conductive Catalyst Bed for Steam Methane Reforming
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Solution Overview
Problem
Steam reforming processes face challenges in efficient heat transfer to the catalyst bed, leading to high energy consumption and larger reactor sizes, with external heat sources like flue gas from fired reformers being inefficient and requiring more catalyst and reactor volume.
Innovation Solution
A hydrogen plant with a reforming reactor system that integrates electrically conductive and catalytically active materials, where resistance heating supplies heat directly to the catalyst bed within the reactor, reducing the need for external heat sources and allowing for higher temperature and pressure operation with less catalyst and reactor volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional external heat transfer methods (convection, conduction, radiation) are used to heat the catalyst bed, then the reactor system can be simpler in design, but the heat transfer efficiency is low and energy consumption is high
Solution Approach 1:
The patent combines the heating function and catalytic reforming function into a single integrated system. Electrically conductive catalyst particles serve both as the catalytic bed and as the heating element, eliminating the need for separate external heating systems and improving heat transfer efficiency while reducing overall energy consumption.
Solution Approach 2:
The patent replaces conventional mechanical/thermal heat transfer systems (fired reformers with flue gas) with an electrical heating system. Electric current is passed through the conductive catalyst particles to generate heat directly within the catalyst bed, providing more efficient and controllable heating compared to external convection and conduction methods.
2Quantity of substance
If external fired reformers are used to provide heat for steam methane reforming, then the reactor design can be simpler, but the reactor size and catalyst amount must be increased to compensate for heat transfer losses
Solution Approach 1:
The heating and catalytic functions are merged into the same material - the catalyst particles themselves are electrically conductive and generate heat when electrical current passes through them. This eliminates heat transfer losses through reactor walls and reduces the amount of catalyst needed compared to external firing systems.
Solution Approach 2:
The patent changes the physical state and properties of the catalyst by making it electrically conductive. This allows the catalyst to directly generate heat through Joule heating when electrical current passes through it, fundamentally changing how heat is supplied to the reforming reaction and reducing the required catalyst quantity.
3Productivity
If high temperature operation is achieved through external firing, then the reforming reaction efficiency improves, but the system produces high emissions and requires complex heat management
Solution Approach 1:
The patent replaces the combustion-based external firing system with direct electrical heating of the catalyst bed. This substitution eliminates the production of flue gas and associated emissions while maintaining the high temperatures needed for efficient steam methane reforming reaction.
Solution Approach 2:
The patent converts electrical energy directly into thermal energy within the catalyst bed through Joule heating. This approach transforms an clean energy source (electricity, especially from renewable sources) into the high temperatures needed for reforming, avoiding the harmful emissions associated with fossil fuel combustion while maintaining high productivity.
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 configuration reduces overall energy consumption, minimizes catalyst usage, and produces high-pressure, high-temperature hydrogen with reduced emissions, enabling more efficient and compact hydrogen production while using renewable energy sources.
Implementation Method 1
the electrical power supply is dimensioned to heat at least part of the first catalyst bed to a temperature of at least 500°C by passing an electrical current through the electrically conductive material
Implementation Method 2
the temperature at the innermost part of the tubes of the tubular reformer is somewhat lower than the temperature outside the tubes due to the heat transfer rate through the walls of the tube and to the catalyst within the tubes as well as due to the endothermic nature of the steam reforming reaction
Data Source
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AI summary
The invention relates to a hydrogen plant for producing hydrogen, comprising: - a reforming reactor system comprising a first catalyst bed comprising an electrically conductive material and a catalytically active material, a heat insulation layer between the first catalyst bed and the pressure shell, and at least two conductors electrically connected to the electrically conductive material and to an electrical power supply placed outside the pressure shell, wherein the electrical power supply is dimensioned to heat at least part of the first catalyst bed to a temperature of at least 500°C by passing an electrical current through the electrically conductive material, where the pressure shell has a design pressure of between 5 and 200 bar, preferably between 30 and 200 bar, more preferably between 80 and 180 bar, - a water gas shift unit downstream the reforming reactor system, and - a gas separation unit downstream the water gas shift unit. The invention moreover relates to a process for producing hydrogen from a feed gas comprising hydrocarbons.