Electrolyzer Flue Gas CO2 Capture and Recycling
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Solution Overview
Problem
Carbon dioxide from flue gas is stable and non-reactive, making it difficult to convert into valuable products, and existing capture methods are energy-intensive and costly.
Innovation Solution
A method involving the combustion of a fuel stream in the presence of an oxygen-enriched carbon dioxide stream from an electrolyzer, followed by cooling and separation to produce a carbon dioxide rich gas stream, which is then recycled to the electrolyzer to generate a second oxygen-enriched carbon dioxide stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carbon dioxide capture methods are used, then carbon dioxide can be captured from flue gas, but the process is energy-intensive and costly
Solution Approach 1:
The patent combines the carbon dioxide capture process with a chemical conversion process in a single integrated system. The flue gas is directly fed into a reactor where carbon dioxide is converted to carbon monoxide and oxygen simultaneously, eliminating the need for separate capture and purification steps that consume additional energy.
Solution Approach 2:
The patent changes the chemical parameters of the flue gas by controlling the oxygen concentration and temperature in the reactor. By maintaining low oxygen concentration (1-10%) and specific temperature ranges, the system promotes selective conversion of carbon dioxide to carbon monoxide while preventing unwanted side reactions, thereby improving capture efficiency without excessive energy input.
2Object-generated harmful factors
If carbon dioxide is converted into other substances, then climate-damaging effects can be reduced, but the conversion is difficult due to carbon dioxide stability and low reactivity
Solution Approach 1:
The patent introduces an intermediary substance (hydrocarbon or carbonaceous material) that facilitates the conversion of carbon dioxide. This intermediary acts as a reducing agent that reacts with carbon dioxide to produce carbon monoxide and water, bypassing the need for direct decomposition of stable carbon dioxide molecules and simplifying the overall conversion process.
Solution Approach 2:
The patent uses controlled oxidation conditions with limited oxygen supply to accelerate the conversion reaction. By carefully controlling the oxygen concentration to be low (1-10%), the system promotes partial oxidation reactions that convert carbon dioxide to carbon monoxide more readily, overcoming the natural stability and low reactivity of carbon dioxide.
3Power
If carbon dioxide is used to generate energy by incineration, then energy can be produced, but this is not possible since carbon is in its highest oxidation state
Solution Approach 1:
Instead of trying to oxidize carbon dioxide to generate energy (which is impossible since carbon is already in its highest oxidation state), the patent inverts the approach by reducing carbon dioxide to carbon monoxide. This reverse chemical transformation allows the carbon to be in a lower oxidation state, making it potentially usable for energy generation applications.
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 process efficiently converts carbon dioxide into valuable products by simplifying the conversion process and reducing energy consumption, while also enabling the recycling of carbon dioxide for continuous use.
Implementation Method 1
an electrolyzer comprising an anode, a cathode, and an electrolyte inserted between the anode and the cathode and configured to receive a first carbon dioxide rich gas stream to the anode to generate an oxygen enriched carbon dioxide stream
Implementation Method 2
a combustion unit configured to combust a fuel stream in the presence of the oxygen enriched carbon dioxide stream received from the anode of the electrolyzer to generate a hot flue gas stream
Implementation Method 3
a heat exchanger configured to cool the hot flue gas stream by supplying a water stream as a heat transfer medium to generate a cooled flue gas stream effluent
Data Source
AI summary
A method includes combusting a fuel stream in a combustion unit in the presence of a first oxygen enriched carbon dioxide stream received from an anode of an electrolyzer to generate a hot flue gas stream comprising carbon dioxide, steam, unconsumed oxygen, NOx and SOx, cooling the hot flue gas stream in a heat exchanger by supplying a water stream to the heat exchanger as a heat transfer medium to generate a cooled flue gas stream effluent, processing the cooled flue gas stream effluent in one or more separation units to generate a carbon dioxide rich gas stream and a carbon dioxide lean gas stream, and passing the carbon dioxide rich gas stream to the anode of the electrolyzer to generate a second oxygen enriched carbon dioxide stream for sending to the combustion unit.