Deep Bubble Column Fermentation for Syngas Conversion
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Solution Overview
Problem
Deep, bubble column reactors face low conversion efficiencies for hydrogen and carbon monoxide due to carbon monoxide inhibition and inefficient mass transfer, leading to high operational and capital costs, especially when trying to achieve high bioconversion rates.
Innovation Solution
The use of two deep, bubble column reactors in flow series with specific feed gas compositions and injection methods, including a motive liquid to produce microbubbles, limits carbon monoxide conversion in the upstream reactor, and optimizes the mole ratios and pressures to minimize inhibition and enhance mass transfer, allowing for high conversion efficiencies of carbon monoxide and hydrogen to oxygenated organic compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If stirred tank reactors with mechanical agitation are used to improve mass transfer, then mass transfer efficiency improves, but energy consumption and capital costs increase significantly
Solution Approach 1:
The patent replaces mechanical agitation systems with a gas sparging system that introduces substrate gas directly into the liquid phase. This substitution eliminates the need for high-energy mechanical impellers while achieving effective mass transfer through bubble formation and rising, thereby resolving the contradiction between mass transfer efficiency and energy consumption.
Solution Approach 2:
The invention utilizes pneumatic principles by sparging substrate gas through the liquid culture medium. The gas flow itself provides the mixing and mass transfer function that would otherwise require mechanical agitation, using gas pressure and flow dynamics instead of mechanical energy input.
2Productivity
If multiple stirred tank reactors are used in series to achieve high conversion, then conversion efficiency improves, but capital costs and system complexity increase
Solution Approach 1:
The patent divides the fermentation process into multiple bubble column reactor stages connected in series. Each stage is a simple bubble column without complex mechanical components, but the segmented arrangement allows progressive conversion of substrate to product, achieving high overall conversion efficiency while maintaining simplicity at each individual stage.
3Ease of manufacture
If deep bubble column reactors are used to reduce capital costs, then capital costs decrease, but conversion efficiency drops due to carbon monoxide inhibition
Solution Approach 1:
The patent segments the deep bubble column reactor into multiple serial stages, allowing the substrate gas composition to be progressively modified through each stage. This segmentation prevents carbon monoxide accumulation and inhibition in any single stage while maintaining the capital cost advantages of simple bubble column design.
Solution Approach 2:
The invention adds the dimension of serial staging to the bubble column reactor design. Instead of relying on a single deep reactor, the process extends through multiple reactor volumes in series, creating a multi-dimensional approach that overcomes the limitations of carbon monoxide inhibition while preserving the simplicity and low capital cost of bubble column technology.
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 achieves high molar conversion efficiencies exceeding 80% of total carbon monoxide and hydrogen, reducing the risk of carbon monoxide inhibition and lowering operational and capital costs compared to traditional stirred tank reactors.
Implementation Method 1
Syngas fermentation processes suffer from the poor solubility of the gas substrate, i.e., carbon dioxide and hydrogen, in the liquid phase of the aqueous menstruum where the biological processes occur.
Implementation Method 2
Anaerobic fermentations of hydrogen and carbon monoxide involve the contact of the substrate gas in a liquid aqueous menstruum with microorganisms capable of generating oxygenated organic compounds such as ethanol
Data Source
AI summary
Bioconversion processes are disclosed that enable high conversion efficiencies of gas substrate containing both carbon monoxide and hydrogen to oxygenated organic compounds via the carbon monoxide and hydrogen pathways using anaerobic, deep, bubble column fermentation in a cost effective manner. The high conversion efficiency processes of this invention comprise the combination of using at least two deep, bubble column reactors in flow series and using certain feed gas compositions and microbubbles while avoiding carbon monoxide inhibition.