Biofuel Synthesis from Fermentation Carboxylic Acids
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high production costs and complex downstream processing associated with recovering carboxylic acids from fermentation broths as salts hinder the cost-competitiveness of bio-based production methods for biofuels like ethanol and biodiesel, as they require additional steps for neutralization and purification, leading to significant waste generation and operational inefficiencies.
Innovation Solution
A process involving the conversion of free carboxylic acids from fermentation broths into their corresponding esters under supercritical or critical conditions using a CO2 atmosphere without additional acid catalysts, followed by hydrogenation or hydrogenolysis to produce biofuels, which simplifies the recovery and recycling of by-products and reduces waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If carboxylic acids are recovered from fermentation broths as salts through neutralization, then the acids can be isolated and purified, but additional processing steps are required including base addition, salt removal, and waste disposal
Solution Approach 1:
The patent extracts carboxylic acids from fermentation broths directly in their free acid form without converting to salts. This is achieved by adjusting pH to below the pKa of the carboxylic acid, causing the acid to precipitate or be easily separable from the broth, thereby eliminating the need for neutralization and subsequent salt removal steps
Solution Approach 2:
Instead of the conventional approach of converting free acid to salt for recovery, this patent inverts the process by directly recovering the free acid form. The method adjusts pH in the opposite direction (acidic rather than basic) to maintain carboxylic acid in its protonated, separable form, thereby simplifying the overall recovery process
2Quantity of substance
If base is added to neutralize fermentation broth for salt formation, then carboxylic acid salts are generated, but equivalent amounts of base reagent are consumed and waste is produced
Solution Approach 1:
The patent employs a self-service approach where the carboxylic acid itself serves as the pH indicator and the fermentation broth's natural buffering capacity is utilized. By adjusting pH to below the acid's pKa, the system automatically favors the free acid form without requiring external base addition for neutralization, thereby eliminating reagent consumption and associated waste
3Ease of manufacture
If calcium salts of C4 diacids are formed, then the salts have low solubility and can be separated, but they are unsuitable for chemical conversion applications requiring free acid species
Solution Approach 1:
The patent applies local quality control by adjusting the pH of specific regions or batches of fermentation broth to below the pKa of the carboxylic acid. This creates localized conditions where the free acid form predominates, making the recovered acid suitable for diverse applications including chemical conversions that require free acid species, while maintaining ease of separation through controlled precipitation
4Manufacturing precision
If multiple operational units are used for salt dissolution, filtration, and waste disposal, then complete acid recovery is achieved, but operational costs increase
Solution Approach 1:
The patent merges multiple operational units into a single integrated process step. By adjusting pH to below pKa and directly recovering free acid through filtration or centrifugation, the process combines what would traditionally require separate steps for neutralization, salt formation, dissolution, and waste disposal into one efficient operation, thereby maintaining complete acid recovery while significantly improving operational efficiency
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 method enhances the efficiency and cost-effectiveness of biofuel production by eliminating the need for neutralization and purification steps, allowing for direct use of free carboxylic acids and recycling of by-products, thereby reducing waste and operational costs while achieving high yields and purity of biofuel products.
Implementation Method 1
drying said fermentation broth containing free carboxylic acids into a powder
Implementation Method 2
reacting said carboxylic acids in said powder with an alcohol solvent or mixture of at least one alcohol under a CO2 atmosphere in substantial absence of any other acid catalyst at a reaction temperature and pressure that corresponds to supercritical, critical or near critical conditions for the alcohol or CO2 to synthesize the corresponding ester or esters
Implementation Method 3
subjecting the esters formed to either hydrogenolysis or hydrogenation to form one or more biofuels
Data Source
AI summary
A process for producing biofuels compounds directly from carboxylic acid esters recovered from a fermentation system is described. The process involves taking a fermentation broth that has been reduced to a dry powder containing free organic acids; reacting the carboxylic acid in the powder with an alcohol solvent under a CO2-containing atmosphere in substantial absence of any other acid catalyst at a reaction temperature and pressure that corresponds to supercritical, critical or near critical conditions for at least one of the alcohol or CO2 to synthesize an ester, then subjecting the ester to either hydrogenolysis or hydrogenation to form a biofuel.