Anaerobic Fermentation Gas Substrate e/C Ratio Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current processes for anaerobic conversion of hydrogen and carbon oxides to alcohols, such as ethanol and butanol, face challenges in achieving high conversion efficiencies and commercial viability due to low solubility of gases in aqueous media, mass transfer limitations, and inefficient use of substrate gases, leading to high capital and operating costs.
Innovation Solution
The integration of anaerobic fermentation unit operations with substrate gas management to adjust the electron-to-carbon (e/C) ratio in the syngas, using a combination of non-renewable and renewable gas sources, enhances bioconversion efficiency by optimizing the composition of the gas substrate to achieve high conversions of hydrogen and carbon monoxide, particularly in deep tank bioreactors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If deep tank bioreactors are used to increase contact time between substrate gases and aqueous fermentation menstruum, then conversion efficiency of hydrogen and carbon monoxide to alcohol is improved, but capital costs and energy consumption increase
Solution Approach 1:
The patent applies parameter changes by adjusting the electron-to-carbon ratio of the substrate gas to an optimal range (2.8:1 to 3.2:1) to maximize conversion efficiency. This involves changing the composition parameters of the gas mixture (hydrogen, carbon monoxide, carbon dioxide ratios) rather than changing the physical structure of the bioreactor, thereby achieving high productivity without increasing capital costs.
Solution Approach 2:
The patent uses partial action by selectively optimizing only the critical parameter (electron-to-carbon ratio) rather than controlling all gas composition variables. This focused approach achieves effective conversion without the need for complex control systems or oversized equipment, reducing capital expenditure while maintaining high productivity.
2Productivity
If deep tank bioreactors are used to increase contact time between substrate gases and aqueous fermentation menstruum, then conversion efficiency of hydrogen and carbon monoxide to alcohol is improved, but energy consumption increases
Solution Approach 1:
The patent reduces energy consumption by changing the compositional parameters of the substrate gas to achieve optimal electron-to-carbon ratio. This chemical parameter optimization enhances mass transfer efficiency and conversion rates without requiring additional energy input for mixing, heating, or extended contact times, thereby improving productivity while minimizing energy use.
Solution Approach 2:
The optimized substrate gas composition enables the fermentation process to proceed more efficiently on its own, with the microorganisms converting substrates at higher rates without requiring external energy input to extend contact time. The system becomes self-optimizing through proper substrate formulation rather than energy-intensive mechanical intervention.
3Productivity
If substrate gas composition is optimized to achieve high conversion, then bioconversion efficiency is improved, but process complexity increases
Solution Approach 1:
The patent simplifies the overall process by focusing on changing a single critical parameter (electron-to-carbon ratio) rather than implementing multiple complex control mechanisms. This parameter-based approach achieves high bioconversion efficiency through straightforward gas mixture formulation, avoiding the need for complex process control systems or multiple processing stages.
Solution Approach 2:
The patent applies partial action by optimizing only the essential substrate gas composition parameters (hydrogen, carbon monoxide, and carbon dioxide ratios) to achieve the target electron-to-carbon ratio. This selective optimization achieves effective bioconversion without implementing comprehensive control over all possible process variables, thereby maintaining process simplicity while improving productivity.
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 results in high conversion efficiencies of hydrogen and carbon oxides to alcohols, with up to 95% conversion, and produces alcohols with a significant renewable carbon content, reducing costs and environmental impact while improving the economic viability of the process.
Implementation Method 1
Anaerobic fermentations of hydrogen and carbon monoxide involve the contact of the substrate gas in an aqueous fermentation menstruum with microorganisms capable of generating alcohols such as ethanol, propanol, i-butanol and n-butanol
Implementation Method 2
hydrogen and carbon oxides pass from the gas phase to being dissolved in the aqueous menstruum, and then the dissolved hydrogen and carbon oxides contact the microorganisms for bioconversion
Data Source
AI summary
Integrated processes are disclosed for the anaerobic bioconversion of syngas to alcohol.