Soapstock Acidulation for Free Fatty Acid Yield
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Solution Overview
Problem
Current methods for processing soapstock and generating free fatty acids from natural oil refining byproducts are inefficient, resulting in low-value waste streams and unconverted saponifiable materials, with existing technologies failing to maximize fatty acid yield.
Innovation Solution
A method involving thermal hydrolysis of a mixed lipid feedstock, followed by acidulation with carbon dioxide to generate free fatty acids, and subsequent esterification to produce fatty acid alkyl esters, which includes multiple acidulation steps to achieve high fatty acid yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional chemical refining processes are used to remove gums and soaps from crude oil, then purification of the oil is improved, but low-value waste streams are generated and fatty acid yield is not maximized
Solution Approach 1:
The patent applies parameter changes by modifying the chemical environment through pH adjustment and temperature control to convert soaps into free fatty acids. By acidulating the soapstock to a pH of 2-4 and heating to 60-100°C, the soaps are converted to free fatty acids that can be separated and recovered, thereby maximizing fatty acid yield from what would otherwise be waste streams.
Solution Approach 2:
The patent uses an intermediary substance (acidifying agent such as phosphoric acid or food-grade acid) to facilitate the conversion of soaps to free fatty acids. This intermediary enables the transformation of the waste soapstock into valuable free fatty acids without directly processing the soap molecules themselves, thus resolving the contradiction between purification and substance recovery.
2Quantity of substance
If soapstock is acidulated to generate free fatty acids, then fatty acid yield is improved, but additional processing steps and costs are required
Solution Approach 1:
The patent merges multiple processing functions into a single integrated system. The acidulation, heating, separation, and concentration steps are combined into one continuous process flow where soapstock is acidulated, heated to separate free fatty acids, and the resulting mixture is concentrated in a single operational sequence, reducing the number of discrete processing steps and equipment requirements.
Solution Approach 2:
The patent implements continuous processing where soapstock continuously flows through the acidulation and heating stages, and free fatty acids are continuously separated and concentrated. This continuous action eliminates idle time between steps and maintains productive operation throughout the process, reducing overall processing complexity despite the multiple transformations involved.
3Loss of substance
If washwater with low lipid content is further processed, then fatty acid recovery is improved, but processing costs increase due to low lipid concentration
Solution Approach 1:
The patent applies local quality by targeting specific regions or streams with different processing intensities. Instead of uniformly processing all waste streams, the method focuses acidulation and recovery efforts on streams containing soaps and saponifiable materials, while treating low-lipid washwater through selective concentration steps only when economically viable, thereby optimizing the balance between recovery and cost.
Solution Approach 2:
The patent implements a selective recovery strategy where washwater with insufficient lipid content (below economic threshold) is discarded or sent to low-value markets, while streams with adequate soap and saponifiable material content are recovered through acidulation and processing. This selective approach maximizes economic efficiency by recovering only those streams where the value of recovered fatty acids exceeds the processing cost.
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 process effectively converts soapstock and other byproducts into high-value free fatty acids and fatty acid alkyl esters, maximizing yield and value from natural oil refining waste streams.
Implementation Method 1
The mixed lipid feedstock is first heated and pressurized (hereinafter referred to as 'thermal hydrolysis') to produce fatty acids
Implementation Method 2
The reacted first mixture is combined with an acid or acid solution, thereby acidulating the soaps unreacted in the first step to generate additional free fatty acids
Implementation Method 3
The generated free fatty acids can be esterified with an alcohol to form a second mixture, thereby esterifying substantially all of the free fatty acids to generate fatty acid alkyl esters
Data Source
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AI summary
Provided are methods, processes and systems for treating a soapstock. In alternative embodiments, provided are systems and methods for treating a soapstock to generate free fatty acids and/or fatty acid derivatives, e.g. fatty acid alkyl esters. In alternative embodiments, provided are systems and methods for realizing the full fatty acid yield of a soapstock by first converting substantially all of the saponifiable material in a soapstock to salts of fatty acids (soaps) and acidulating the soaps to generate free fatty acids and/or fatty acid derivatives, e.g. fatty acid alkyl esters, wherein the soapstock comprises soaps and saponifiable lipids, e.g. glycerides and/or phospholipids, and the generating of free fatty acids and/or fatty acid is achieved.