Solid Oxide Electrolysis Cell for CO2 Capture
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Solution Overview
Problem
Conventional combustion processes in refineries face challenges in capturing CO2 due to high nitrogen content in flue gases, making it cost-prohibitive to capture significant amounts of CO2 emissions, and the high capital and operating costs associated with air separation units for oxygen-fuel combustion processes.
Innovation Solution
A process utilizing a solid oxide electrolysis cell to produce a feed containing oxygen and CO2, which is then mixed with a portion of the flue gas to create an enhanced feed for combustion, resulting in flue gases with greater than 50 wt % CO2 and less than 1 wt % N2, thereby reducing the need for nitrogen separation and lowering operational costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional combustion processes are used, then the combustion process can operate with air as oxidant, but the flue gas contains mostly nitrogen making CO2 capture cost prohibitive
Solution Approach 1:
The patent extracts nitrogen from the combustion process by using oxygen-enriched air instead of conventional air. This removes the harmful nitrogen component before combustion occurs, preventing it from entering the flue gas stream and eliminating the need for costly nitrogen separation and CO2 capture from nitrogen-rich flue gases.
Solution Approach 2:
The patent changes the oxygen concentration parameter in the combustion air from conventional levels (21% O2) to oxygen-enriched levels (30-50% O2). This parameter change fundamentally alters the flue gas composition, reducing nitrogen content and increasing CO2 concentration, which enables practical CO2 capture without expensive amine scrubbing of nitrogen-rich streams.
2Quantity of substance
If oxygen-fuel combustion process is used to increase CO2 capture, then CO2 concentration in flue gas increases, but the capital and operating costs of air separation units become prohibitive
Solution Approach 1:
The patent applies partial oxygen enrichment (30-50% O2) rather than complete oxygen fuel combustion (100% O2). This partial action achieves sufficient CO2 concentration in flue gas for practical capture while avoiding the need for full-scale air separation units, thereby reducing capital and operating costs significantly compared to complete oxygen-fuel combustion.
Solution Approach 2:
The patent uses an intermediary approach by mixing oxygen-enriched air with the combustion process rather than using pure oxygen. This intermediary solution (oxygen-enriched air at 30-50% concentration) serves as a middle ground between conventional air and pure oxygen, achieving good CO2 concentration without requiring expensive complete air separation infrastructure.
3Quantity of substance
If amine scrubbing is used to remove CO2 from flue gas, then CO2 can be captured from high CO2 partial pressure streams, but it is cost prohibitive for nitrogen-rich combustion flue gas
Solution Approach 1:
The patent performs preliminary action by enriching the combustion air with oxygen before combustion occurs. This pre-combustion oxygen enrichment prevents nitrogen from entering the flue gas stream in the first place, thereby eliminating the need for subsequent costly CO2 capture from nitrogen-rich flue gases. The problem is solved upstream rather than requiring expensive downstream treatment.
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 effectively increases the amount of CO2 captured from combustion processes, reduces nitrogen emissions, and lowers the operational costs by eliminating the need for costly air separation units, while maintaining safety and efficiency.
Implementation Method 1
A first portion of the flue gas produced from a combustion process is directed to the anode side of the solid oxide electrolysis cell to produce a feed containing oxygen and CO2
Implementation Method 2
The enhanced feed is then mixed with fuel and combusted in the combustion process to produce flue gas
Data Source
AI summary
A process of producing a feed from a solid oxide electrolysis cell. A first portion of the flue gas produced from a combustion process is directed to the anode side of the solid oxide electrolysis cell. The feed and a second portion of the flue gas are then mixed to produce an enhanced feed. The enhanced feed is then mixed with fuel and combusted in the combustion process to produce flue gas. The flue gas comprises greater than 50 wt % CO2 and less than 1 wt % N2.