Two-Stage Vegetable Oil Refining for Low MCPDe and Glycidyl Esters
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Solution Overview
Problem
Existing refining processes for vegetable oils are inadequate in achieving low levels of monochloropropanediol esters (MCPDe) and glycidyl esters, while being compatible with conventional methods and minimizing process modifications.
Innovation Solution
A two-stage process involving degumming, bleaching under reduced pressure, addition of a base, and subsequent stripping and deodorization at controlled temperatures and pressures to yield fully refined vegetable oil with low MCPDe and glycidyl ester content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional refining processes are used, then the refining process is simple and compatible with existing methods, but the content of MCPDe and glycidyl esters remains high
Solution Approach 1:
The refining process is divided into two distinct stages: a first refinement stage using conventional methods (degumming, bleaching, deodorization) and a second refinement stage using vacuum distillation. This segmentation allows each stage to perform its specific function optimally - the first stage handles bulk impurity removal with simple equipment, while the second stage specifically targets MCPDe and glycidyl ester removal through vacuum distillation, achieving low contaminant levels without requiring complete process redesign
Solution Approach 2:
The first refinement stage performs preliminary removal of major impurities (phospholipids, free fatty acids, pigments) before the second refinement stage. This preliminary action reduces the load on the vacuum distillation process, allowing it to focus specifically on removing MCPDe and glycidyl esters at lower temperatures and pressures, thereby maintaining overall process simplicity while achieving the desired purification precision
2Productivity
If high temperature deodorization is used to remove impurities, then impurity removal efficiency is improved, but formation of MCPDe increases
Solution Approach 1:
The process changes the operational parameters of the deodorization step by conducting it under reduced pressure (vacuum conditions). This parameter change allows impurity removal at lower temperatures than conventional atmospheric deodorization, thereby reducing the thermal energy available for MCPDe formation reactions while maintaining effective impurity removal through the combined effect of reduced boiling points and extended contact time in the vacuum distillation stage
3Manufacturing precision
If vacuum distillation at high temperature is used to reduce MCPDe, then MCPDe content is reduced, but energy consumption and process complexity increase
Solution Approach 1:
The first refinement stage removes bulk impurities and reduces the concentration of precursors that could form MCPDe during vacuum distillation. This preliminary action decreases the load on the second refinement stage, allowing vacuum distillation to operate at lower temperatures and for shorter durations, thereby reducing energy consumption while still achieving the target MCPDe content levels
Solution Approach 2:
By segmenting the refining process into two stages with different functional focuses, the energy-intensive vacuum distillation step only needs to handle the remaining trace impurities and MCPDe removal rather than performing all refining functions. This segmentation optimizes energy usage by matching each stage's energy input to its specific purification task, avoiding excessive energy consumption
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
The process effectively reduces MCPDe and glycidyl esters to levels below 4 ppm, preferably below 2 ppm, achieving a significant reduction in undesirable compounds in refined vegetable oils.
Implementation Method 1
bleaching of the degummed vegetable oil with activated bleaching earth under reduced pressure
Implementation Method 2
adding a base to the bleached vegetable oil and subsequent stripping and deodorizing
Implementation Method 3
subsequent stripping and deodorizing under reduced pressure at a temperature below 255 °C
Implementation Method 4
subjecting the refined oil to a vacuum distillation at about 200-280° C. and at pressure of about 0.0001-3.0 mbar
Data Source
AI summary
Process for refining vegetable oil, to suppress the formation of monochloropropanediol esters (MCPDe) and reduce the content of glycidyl esters, comprising first and second refinement stages, wherein the first refinement stage comprises the steps of: a) providing a crude vegetable oil having a combined MCPDe and glycidyl ester content below 0.2 ppm, preferably below 0.1 ppm; b) degumming the crude vegetable oil to produced degummed vegetable oil; c) bleaching of the degummed vegetable oil with activated bleaching earth under reduced pressure to yield bleached vegetable oil, preferably at a reduced pressure of 80-800 mbar; d) adding a base to the bleached vegetable oil and subsequent stripping and deodorizing under reduced pressure at a temperature below 255 °C to yield an intermediate refined vegetable oil; and subsequently a second refinement stage comprising the steps of: e) bleaching of the intermediate refined vegetable oil using activated bleaching earth under reduced pressure to yield a bleached vegetable oil, preferably at a reduced pressure of 80-800 mbar; and f) deodorizing at a temperature below 220°C to yield fully refined vegetable oil, preferably at a reduced pressure below 5 mbar, wherein the fully refined vegetable oil has a combined MCPDe and glycidyl ester content below 4 ppm.