Microbial Fermentation for Carbon Capture from Steel Mill Off-Gas
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Solution Overview
Problem
Current microbial fermentation processes for ethanol production from carbon monoxide face inefficiencies due to co-production of acetate, potential greenhouse gas emissions, and the need for additional scrubbing and treatment steps, which increase costs and environmental impact.
Innovation Solution
A system and method for capturing carbon through microbial fermentation using off-gas streams from industrial processes, incorporating CO2 removal and gas separation to optimize CO concentration, and utilizing scrubber water as a feedstock, reducing pre-processing steps and enhancing carbon capture efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If microbial fermentation is used to convert CO to ethanol, then carbon capture efficiency is improved, but acetate and acetic acid are co-produced as waste products
Solution Approach 1:
The patent converts the harmful acetate by-product into a useful resource by introducing acetate-utilizing microorganisms that transform acetate into methane and CO2. This transforms the waste product into valuable energy carriers, simultaneously improving carbon capture efficiency while eliminating the acetate waste problem through biological conversion.
Solution Approach 2:
The patent recovers carbon from acetate and acetic acid by-passing these compounds through additional microbial conversion processes. The acetate is converted to methane and CO2, which are then captured and utilized, thereby recovering carbon that would otherwise be lost in the acetate by-product stream.
2Reliability
If traditional scrubbing and treatment steps are implemented, then gas purification is improved, but operational costs and environmental impact increase
Solution Approach 1:
The patent employs microbial communities that naturally degrade contaminants in the CO gas stream without requiring external scrubbing equipment. The microorganisms utilize contaminants as carbon sources for their metabolism, automatically purifying the gas through biological processes rather than mechanical or chemical scrubbing systems.
Solution Approach 2:
The patent replaces traditional mechanical and chemical scrubbing systems with biological conversion processes. Instead of using physical filters, absorbers, or chemical reagents to remove contaminants, the system uses microbial metabolism to transform contaminants into useful products, eliminating the need for complex purification infrastructure.
3Ease of operation
If acetate by-product is released into the environment, then waste disposal is simplified, but greenhouse gas emissions increase
Solution Approach 1:
The patent converts the harmful acetate by-product into methane and CO2 through microbial action. These converted products are then captured and utilized as carbon sources for ethanol production, transforming the greenhouse gas-emitting waste stream into a valuable resource that contributes to carbon capture rather than environmental pollution.
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 enhances ethanol production efficiency, reduces waste, and minimizes environmental impact by directly utilizing industrial off-gases in fermentation without extensive pre-treatment, thereby improving carbon capture and lowering operational costs.
Implementation Method 1
The vast majority of fuel ethanol is produced via traditional yeast-based fermentation processes
Implementation Method 2
This was later determined to be a property of organisms that use the acetyl coenzyme A (acetyl CoA) biochemical pathway of autotrophic growth (also known as the Woods-Ljungdahl pathway and the carbon monoxide dehydrogenase / acetyl CoA synthase (CODH/ACS) pathway)
Implementation Method 3
CO2 may be removed from the gas stream by any suitable method, including, but not limited to, absorption by amine solutions
Implementation Method 4
Gas separation may be performed to separate at least one component of the gas stream, such as CO, CO2, H2, or a combination thereof
Data Source
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AI summary
The invention relates to methods of capturing carbon by microbial fermentation of a gaseous substrate comprising CO. The methods of the invention include converting CO to one or more products including alcohols and/or acids and optionally capturing C02 to improve overall carbon capture. In certain aspects, the invention relates to processes for producing alcohols, particularly ethanol, from industrial waste streams, particularly steel mill off-gas.