Electrolytic Scrubber CO2 Recovery via Off-Gas Recycle
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Solution Overview
Problem
Existing carbon capture systems in electrolytic regeneration processes are inefficient in increasing the uptake of carbon dioxide, leading to significant emissions and energy consumption.
Innovation Solution
A method and system that involves scrubbing gases with an alkaline, aqueous scrubbing liquid to dissolve CO2, regenerating the spent liquid in an electrolytic cell, and reintroducing a secondary stream of CO2-rich off-gas into the spent liquid to enhance carbon loading, optimizing pH and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spent scrubbing liquid is regenerated in an electrolytic process with conventional off-gas release, then the scrubbing liquid is regenerated and CO2 is separated, but carbon capture efficiency is low and significant CO2 emissions occur
Solution Approach 1:
The patent recovers CO2 from the anode off-gas that would otherwise be discarded, by injecting it back into the spent scrubbing liquid to enhance carbon loading before electrolytic regeneration
Solution Approach 2:
The patent converts the harmful CO2 emissions in the anode off-gas into a beneficial resource by using it to increase carbon loading in the scrubbing liquid, thereby improving overall carbon capture efficiency
2Quantity of substance
If more scrubbing liquid is used to increase CO2 uptake capacity, then more CO2 can be absorbed, but the amount of liquid to be regenerated increases energy consumption
Solution Approach 1:
The patent changes the carbon loading parameter of the scrubbing liquid by injecting CO2-rich off-gas, thereby increasing CO2 uptake capacity without proportionally increasing the volume of liquid to be regenerated
Solution Approach 2:
The patent uses CO2 from the off-gas to enhance carbon loading in the scrubbing liquid, creating a concentrated CO2 source that improves uptake capacity without requiring additional liquid volume
3Manufacturing precision
If CO2-rich off-gas is compressed and separated into pure CO2 and oxygen, then pure CO2 is obtained for downstream applications, but energy consumption for compression and separation increases
Solution Approach 1:
The patent uses the CO2-rich off-gas to enhance carbon loading in the scrubbing liquid itself, allowing the system to serve its own need for CO2 concentration without requiring external compression and separation energy
Solution Approach 2:
The patent merges the CO2 separation function with the scrubbing liquid regeneration process by injecting off-gas directly into the liquid, combining what would be separate operations into one integrated step
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
Enhances carbon capture efficiency by increasing the carbon load in the scrubbing liquid, reducing the amount of scrubbing liquid needed, and lowering energy requirements for compression and separation, while producing valuable hydrogen and oxygen for downstream applications.
Implementation Method 1
scrubbing the gas in a scrubber with a first alkaline, aqueous scrubbing liquid to dissolve carbon dioxide as hydrogen carbonate (HCO3−) and/or as carbonate (CO32−) in the first alkaline, aqueous scrubbing liquid
Implementation Method 2
regenerating the first spent aqueous scrubbing liquid in the electrolytic cell (310) by electrolysis, depleting the first spent aqueous scrubbing liquid of hydrogen carbonate (HCO3−) and of carbonate (CO32−) in the anode chamber (313, the regeneration further comprising generating gaseous hydrogen in the cathode chamber (312) and a gaseous mixture of oxygen and carbon dioxide (CO2) in the anode chamber (313) by electrolysis
Implementation Method 3
wherein carbon dioxide (CO2) and/or oxygen (O2) withdrawn from the anode chamber is compressed into liquid carbon dioxide and compressed oxygen (O2), in a compression unit
Implementation Method 4
separating the liquid carbon dioxide from gaseous oxygen, in a gas separator, into a first stream comprising carbon dioxide, and a secondary stream comprising oxygen
Data Source
AI summary
There is a method has the steps of (A) scrubbing the gas in a scrubber with a first alkaline, aqueous scrubbing liquid to provide a first spent aqueous scrubbing liquid; (B) feeding the first spent aqueous scrubbing liquid to an electrolytic cell having an anode chamber and a cathode chamber; (C) regenerating the first spent aqueous scrubbing liquid by electrolysis; and (D) withdrawing regenerated alkaline, aqueous scrubbing liquid from the cathode chamber and recirculating it to the scrubber. The method has a step of separating a liquid carbon dioxide from gaseous oxygen in a gas separator into (i) a first stream having carbon dioxide, and (ii) a secondary stream having oxygen containing less than 30% carbon dioxide. The secondary stream is introduced into at least a portion of the first spent aqueous scrubbing liquid prior to feeding the first spent aqueous scrubbing liquid into the anode chamber.