Biodiesel Production via Liquid and Immobilized Lipase Catalysis
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Solution Overview
Problem
Current biodiesel production methods using chemical catalysts face challenges such as interference from free fatty acids and water in feedstock, emulsion formation, and high energy consumption due to excess methanol usage, which affect product quality and yield.
Innovation Solution
A method utilizing liquid lipase in combination with immobilized lipase, where oil and fat are reacted with short-chain alcohol and water, with online dehydration, allowing enzyme recovery and reuse, to achieve high biodiesel yield and low acid value without preprocessing, using membranes and molecular sieves for separation and dehydration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chemical catalysts are used for biodiesel production, then the reaction efficiency is improved, but the product quality deteriorates due to interference from free fatty acids and water
Solution Approach 1:
The patent changes the catalytic mechanism from chemical catalysis to enzymatic catalysis using lipase, operating at mild temperatures (30-60°C) and neutral pH conditions. This parameter change allows the reaction to proceed efficiently while being tolerant of free fatty acids and water in the feedstock, thus maintaining both high productivity and product quality without requiring extensive pretreatment of the oil feedstock.
Solution Approach 2:
The patent introduces lipase enzyme as an intermediary catalyst that mediates the transesterification reaction between oil and alcohol. The enzyme acts as a selective mediator that can process feedstock containing impurities (free fatty acids and water) without being inhibited, unlike chemical catalysts. The enzyme's active site selectively binds and processes the triglycerides while tolerating the presence of impurities, thus resolving the contradiction between reaction efficiency and product quality.
2Speed
If chemical catalysts are used, then the reaction proceeds quickly, but emulsion formation complicates subsequent processing
Solution Approach 1:
The lipase enzyme serves as a mediator that promotes phase separation by catalyzing the reaction at the oil-alcohol interface. The enzyme's amphiphilic nature allows it to work effectively at the interface between immiscible phases, facilitating mass transfer and promoting complete phase separation after reaction, thereby preventing emulsion formation and simplifying downstream processing while maintaining fast reaction kinetics.
Solution Approach 2:
The patent utilizes phase transition phenomena where the reaction mixture separates into distinct phases (biodiesel phase, glycerol phase, and enzyme phase) after completion of the transesterification reaction. This natural phase separation, facilitated by the enzymatic reaction conditions, eliminates emulsion stability issues and simplifies the separation and purification steps in the processing workflow.
3Manufacturing precision
If excess methanol is used according to process requirements, then the reaction completeness is improved, but energy consumption increases due to methanol recovery
Solution Approach 1:
The patent changes the reaction conditions to use molar ratios of alcohol to oil closer to the stoichiometric requirement (typically 3:1 to 6:1), compared to chemical catalysis which requires large excess (10:1 or higher). The enzymatic reaction conditions, including optimized temperature (30-60°C) and the use of water in the reaction mixture, enhance the effectiveness of the alcohol, allowing complete reaction with smaller excess and reducing the energy required for alcohol recovery and recycling.
4Ease of manufacture
If water content in feedstock is greater than 0.5%, then the reaction can proceed with crude oil, but the acid value of biodiesel exceeds quality standards
Solution Approach 1:
The lipase enzyme acts as a selective intermediary that catalyzes the transesterification of triglycerides while being insensitive to the presence of water and free fatty acids in the feedstock. The enzyme's active site specifically binds and processes the ester bonds in triglycerides, leaving water and free fatty acids unaffected. This selectivity allows the use of crude oil feedstock with water content above 0.5% while maintaining control over the acid value of the produced biodiesel, as the enzyme does not promote unwanted side reactions that would increase acid value.
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 achieves a biodiesel conversion rate exceeding 98% with an acid value below 0.5 mg KOH per gram of oil, reducing environmental impact and energy consumption while maintaining product quality.
Implementation Method 1
a method for preparing biodiesel using a liquid lipase in combination with an immobilized lipase
Implementation Method 2
converting oil and fat feedstock for the preparation of biodiesel
Implementation Method 3
the enzyme protein in the heavy phase is separated and recovered using a membrane
Implementation Method 4
an online dehydration with a membrane or a molecular sieve is carried out during the whole reaction process or part of the reaction process
Implementation Method 5
an online dehydration with a membrane or a molecular sieve is carried out
Implementation Method 6
the reaction liquid is then separated into a heavy phase and a light phase
Implementation Method 7
after the reaction liquid is stratified by centrifugation or standing
Data Source
AI summary
The present invention provides a method for preparing biodiesel, comprising: adding oil and fat, short-chain alcohol, water, and liquid lipase into a single-stage or multi-stage enzyme reactor; then separating the reaction fluid into an enzyme-containing heavy phase and a light phase; recovering and reusing the enzyme in the heavy phase; using the light phase for subsequent conversion by immobilized lipase; flowing the light phase and the short-chain alcohol into single-stage or multi-stage enzyme reactor containing an immobilized lipase; performing online dehydration during the whole reaction process or part of the reaction process. In the method of the invention for preparing biodiesel, no preprocessing is required for the oil and fat feedstock in the earlier stage of catalysis process by liquid lipase, and the conversion ratio from oil and fat to biodiesel can reach more than 90%; in the later stage of catalysis process by immobilized lipase, by introducing an online dehydration during the whole process or part of the reaction process, the yield of biodiesel can exceed 98%, and the acid value of the product can be less than 0.5 mg KOH per gram of oil. The method thus has good economic and environmental benefits.