Cyclic Dry Reforming Catalyst Oxygen Vector
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Solution Overview
Problem
Current dry reforming methods for methane face challenges such as low H2/CO ratio, endothermic nature, and rapid catalyst deactivation due to coke formation and reverse water gas-shift reactions, which hinder efficient production of syngas.
Innovation Solution
A cyclic and alternative exposure method using a catalytic solid composed of Me1-Ox1-Ox2, where Me1 is non-reducible under CO2, Ox1 is reducible under alkanes and re-oxidizable under CO2, and Ox2 is inert, acting as an oxygen vector in a periodic manner to produce syngas while avoiding coke formation and reverse water gas-shift reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional fixed bed catalytic chamber is used for dry reforming of methane, then the reaction can proceed at high temperature, but rapid catalyst deactivation occurs due to coke formation
Solution Approach 1:
The patent implements periodic alternation between dry reforming reaction phase and catalyst regeneration phase. During the reaction phase, methane and CO2 are supplied for syngas production. During the regeneration phase, air is supplied to burn off accumulated coke on the catalyst. This periodic operation prevents continuous coke accumulation that would otherwise cause rapid catalyst deactivation, thereby maintaining both productivity and reliability over extended operation periods.
2Productivity
If high temperature operation is used to overcome thermodynamic limits, then endothermic reaction can proceed, but reverse water gas-shift reaction increases reducing selectivity
Solution Approach 1:
The patent uses periodic operation to separate the high-temperature reaction phase from the regeneration phase. During the reaction phase, high temperature promotes the endothermic dry reforming reaction to achieve high productivity. The subsequent regeneration phase with air supply allows controlled oxidation that manages the syngas composition by adjusting the H2/CO ratio, thereby overcoming the selectivity reduction issue caused by reverse water gas-shift reaction.
3Productivity
If conventional catalysts are used, then dry reforming can occur, but H2/CO ratio is lower than other reforming methods
Solution Approach 1:
The patent employs parameter changes by controlling the oxidation conditions during the regeneration phase. By adjusting the air supply rate, temperature, and duration of the regeneration phase, the H2/CO ratio in the produced syngas can be precisely controlled. This allows achieving higher H2/CO ratios comparable to other reforming methods while maintaining the advantage of CO2 consumption capability inherent to dry reforming.
4Manufacturing precision
If periodic operation with coking catalyst is used, then pure hydrogen can be produced, but catalyst acts as carbon vector requiring re-oxidation phase
Solution Approach 1:
The patent implements a self-service mechanism where the catalyst automatically regenerates during the periodic operation. The coke accumulated on the catalyst during the reaction phase is automatically burned off during the regeneration phase when air is supplied. This self-regeneration capability eliminates the need for external catalyst replacement or complex additional regeneration equipment, thereby achieving hydrogen production with acceptable operational simplicity.
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 method achieves a stable and selective production of syngas with an optimal H2/CO ratio of about two, reducing catalyst deactivation and enhancing operational stability by regenerating the catalytic solid in each cycle, thus overcoming the limitations of traditional dry reforming.
Implementation Method 1
said catalytic solid is cyclically and alternatively exposed to a stream of at least one alkane and a stream containing carbon dioxide, such that said catalytic solid is used as an oxidation vector
Implementation Method 2
The reaction is carried out at high temperature (typically 700-900° C.) in order to overcome the thermodynamic limits related to this endothermic reaction
Implementation Method 3
it is endothermic as opposed to partial oxidation reforming
Implementation Method 4
the simultaneous presence of CO2 (reagent) and hydrogen (product) resulting, by the reverse water gas-shift reaction, in a reduction in selectivity
Data Source
AI summary
The present invention relates to a method for dry reforming of at least one alkane carried out in at least one reaction chamber, preferably with a catalytic bed, having a stream of gas passing through same. According to the invention, said at least one reaction chamber comprises a catalytic solid which is cyclically and alternatively exposed to a stream of at least one alkane and a stream containing carbon dioxide, such that said catalytic solid is used as an oxidation vector.