Fuel Synthesis Supply Sequencing for CO2-H2O Electrolysis
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Solution Overview
Problem
The existing energy conversion systems that perform carbon dioxide and water electrolysis and hydrocarbon synthesis in the same portion face efficiency reduction due to factors other than pressure, leading to suboptimal reaction conditions.
Innovation Solution
An energy conversion system comprising a fuel synthesis device with an electrolyte and electrodes, an H2O supply unit, a CO2 supply unit, and a supply control unit, where H2O supply is initiated after CO2 supply, optimizing the chemical equilibrium to reduce reverse water-gas shift reactions and Sabatier reactions, thereby enhancing system efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If H2O and CO2 are supplied simultaneously to the fuel synthesis device, then the system can maintain continuous operation, but the reverse water-gas shift reactions and Sabatier reactions occur excessively, reducing system efficiency
Solution Approach 1:
CO2 is supplied to the fuel synthesis device before H2O is supplied. This preliminary supply of CO2 allows CO to be generated first through electrolysis, which then serves as a reactant for hydrocarbon synthesis when H2O is subsequently supplied, reducing unnecessary reverse water-gas shift reactions and improving energy efficiency
Solution Approach 2:
The supply of H2O and CO2 is controlled in periodic cycles rather than continuously simultaneously. The supply control unit alternates between supplying CO2 first, then H2O, creating periodic reaction conditions that optimize hydrocarbon generation while minimizing energy-wasting side reactions
2Speed
If H2O supply is started before CO2 supply, then the electrolysis reaction can begin immediately, but H2 consumption increases due to excessive reverse water-gas shift reactions
Solution Approach 1:
CO2 supply is initiated as a preliminary action before H2O supply. This ensures that CO is already present in the reaction environment when H2O is introduced, allowing hydrocarbon synthesis to proceed directly without excessive H2 consumption through reverse water-gas shift reactions
3Ease of operation
If the supply timing of H2O and CO2 is not controlled, then the system operation is simple, but the chemical equilibrium is suboptimal, reducing hydrocarbon synthesis efficiency
Solution Approach 1:
The supply control unit dynamically adjusts the timing and sequence of H2O and CO2 supply based on reaction conditions. The system transitions from static simultaneous supply to dynamic sequential supply, optimizing chemical equilibrium and hydrocarbon synthesis rate while maintaining operational simplicity through automated control
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 reduces H2 consumption and electric power usage, increasing hydrocarbon generation rates and overall system efficiency by controlling the timing and ratio of H2O and CO2 supplies to favor hydrocarbon synthesis over byproduct generation.
Implementation Method 1
a fuel synthesis device (10), which electrolyzes H2O and CO2
Implementation Method 2
a cathode that electrochemically reduces carbon dioxide to generate a product such as hydrocarbons
Implementation Method 3
synthesizes a hydrocarbon using H2 generated by electrolysis of H2O and CO generated by electrolysis of CO2
Data Source
AI summary
An energy conversion system includes a fuel synthesis device, an H2O supply unit, a CO2 supply unit, and a supply control unit. The fuel synthesis device includes an electrolyte, and a pair of electrodes provided on both sides of the electrolyte. The H2O supply unit supplies H2O to the fuel synthesis device. The CO2 supply unit supplies CO2 to the fuel synthesis device. The supply control unit controls a supply of H2O and a supply of CO2. The fuel synthesis device electrolyzes H2O and CO2 using external electric power, and synthesizes a hydrocarbon using H2 and CO generated by electrolysis. The supply control unit starts the supply of H2O to the fuel synthesis device by the H2O supply unit after the supply of CO2 to the fuel synthesis device by the CO2 supply unit is started.