Catalytic Two-Zone Reactor for Carbon Dioxide-to-Carbon Monoxide Conversion
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Solution Overview
Problem
Current methods for large-scale conversion of carbon dioxide to carbon monoxide via the reverse water gas shift (RWGS) reaction face challenges in achieving high conversion efficiency at high temperatures while avoiding by-products like methane and carbon formation, requiring substantial thermal energy from external furnaces, which poses engineering difficulties.
Innovation Solution
A two-zone RWGS process where a combustion reaction in the top zone provides heat for the endothermic reaction in the bottom zone using separate hydrogen and oxygen streams, with a catalyst bed in the bottom zone to convert carbon dioxide and hydrogen into carbon monoxide and water, utilizing a burner with coaxial channels to control temperature and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperatures (beyond 600°C) are used to achieve high carbon monoxide production from carbon dioxide via RWGS reaction, then conversion efficiency is improved, but substantial thermal energy is required which poses engineering difficulties
Solution Approach 1:
The patent combines the exothermic combustion reaction and endothermic RWGS reaction into a single reactor system. The combustion zone generates heat in-situ that directly supplies the RWGS reaction zone, eliminating the need for external furnaces and reducing overall energy input requirements while maintaining high CO production efficiency
Solution Approach 2:
The patent utilizes the exothermic combustion reaction (which releases heat) to provide the necessary thermal energy for the endothermic RWGS reaction. By positioning the combustion zone adjacent to the RWGS zone, the waste heat from combustion is converted into useful thermal energy that drives the CO production reaction
2Productivity
If external furnaces are used to provide substantial thermal energy for RWGS reaction, then high conversion efficiency is achieved, but device complexity and engineering difficulty increase
Solution Approach 1:
The patent merges the heating function (combustion) and the reaction function (RWGS) into a single integrated reactor system. This eliminates the need for separate external furnaces and simplifies the overall device architecture while maintaining high conversion efficiency
Solution Approach 2:
The reactor system is designed to be self-heating through the combustion reaction. The system generates its own thermal energy requirements internally through the combustion of hydrogen with oxygen, eliminating the need for external heating infrastructure and reducing device complexity
3Use of energy by moving object
If catalysts are used to enable RWGS reaction at lower temperatures (700-1000°C), then thermal energy requirement is reduced, but catalyst resistance to poisons and high temperature withstand capability must be ensured
Solution Approach 1:
The patent creates distinct zones within the reactor with different functional properties. The combustion zone operates at high temperatures to generate heat, while the RWGS zone operates at lower temperatures where the catalyst can function effectively. This spatial differentiation allows each zone to operate under optimal conditions for its specific function
Solution Approach 2:
The reactor is segmented into functionally distinct zones: a combustion zone for heat generation and an RWGS zone for CO production. This segmentation allows the catalyst to be protected from excessive temperatures and combustion byproducts, maintaining its stability and resistance to poisoning while still achieving the desired reaction
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
Efficient conversion of carbon dioxide to carbon monoxide is achieved at elevated temperatures, minimizing by-products and reducing the need for external heating, thus enhancing process scalability and efficiency.
Implementation Method 1
the hydrogen and oxygen in the hydrogen rich gas stream and oxygen rich gas stream undergo a combustion reaction upon entering the reaction vessel, thereby providing the heating energy required for the reverse water-gas shift reaction
Implementation Method 2
the reaction of carbon dioxide with hydrogen via the RWGS reaction to produce carbon monoxide and water is endothermic in nature. Sufficient thermal energy must be supplied to the reactants
Implementation Method 3
RWGS reaction at lower temperatures at around 700-1000° C. require catalysts to enable the conversion of carbon dioxide to carbon monoxide
Data Source
AI summary
The present invention relates to a process for converting carbon dioxide and hydrogen by performing a reverse water gas shift reaction at elevated temperature, the process comprising introducing carbon dioxide, hydrogen and oxygen into a reaction vessel having an inlet and an outlet, and, wherein the reverse water gas shift reaction takes place in two different zones of the reaction vessel, being a top zone (z1) adjacent to a bottom zone (z2). The process produces a product stream comprising mainly carbon monoxide, hydrogen and water. The process is useful in reducing the carbon footprint of certain industrial technologies, and in addition, the process is useful in the production of synthesis gas.