Physical Refining of Triglyceride Oils via Three-Stage Evaporation
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Solution Overview
Problem
Current physical refining processes for edible oils and fats face challenges in achieving high oil yield and reducing stripping steam requirements, while also producing separate condensate streams with different compositions to maximize value.
Innovation Solution
A three-stage process involving flash evaporation, countercurrent steam stripping using a packed column, and cross-flow tray system, with pressure management in the flash vessel below the packed column, allows for high FFA content condensates and reduced steam consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If physical refining process is used to remove FFA by volatilization, then neutral oil loss is reduced compared to chemical refining, but stripping steam requirements remain high
Solution Approach 1:
The refining process is divided into three sequential stages: flash evaporation stage, countercurrent steam stripping stage, and cross-flow tray stage. Each stage performs a specific function in removing volatiles and FFA, allowing optimization of steam usage at each step rather than using excessive steam in a single stage.
Solution Approach 2:
The flash evaporation stage performs preliminary removal of a significant portion of volatiles and FFA before the oil enters the steam stripping stages. This preliminary action reduces the load on subsequent stages, thereby reducing overall steam requirements while maintaining high FFA removal efficiency.
2Reliability
If high-temperature vacuum stripping is used to remove FFA, then FFA are effectively removed, but energy consumption increases
Solution Approach 1:
The process utilizes pressure changes across different stages - from atmospheric pressure in flash evaporation to vacuum conditions in the stripping stages. This parameter change allows FFA removal to occur at lower temperatures than conventional single-stage high-temperature stripping, reducing energy consumption while maintaining removal efficiency.
Solution Approach 2:
The three stages operate continuously in sequence, with each stage building upon the work of the previous stage. The flash evaporation continuously removes bulk volatiles, followed by continuous steam stripping in the packed column and trays, ensuring efficient FFA removal without requiring excessive temperature or energy input at any single point.
3Reliability
If conventional physical refining is used, then FFA are removed, but separate condensate streams with different compositions are not produced
Solution Approach 1:
The condensation system is segmented into multiple condensers corresponding to different process stages. The first condenser handles vapors from flash evaporation, while subsequent condensers handle vapors from different stripping stages. This segmentation produces separate condensate streams with distinct compositions, enabling versatile utilization of by-products.
Solution Approach 2:
Each condenser is designed to capture specific components based on local process conditions. The first condenser captures high-FFA condensate from flash evaporation, while later condensers capture condensates with different compositions from subsequent stages. This local quality differentiation maximizes the economic value of each condensate stream.
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 enhances oil yield, reduces stripping steam requirements, and produces distinct condensate streams with higher FFA content, improving economic value and operational efficiency.
Implementation Method 1
in a first stage at least 60% by weight of the volatiles are evaporated in a flash vessel
Implementation Method 2
in a second stage some residual volatiles are evaporated by countercurrent steam stripping using a packed column
Implementation Method 3
in a third stage further residual volatiles are evaporated in a cross-flow tray system
Implementation Method 4
wherein the pressure in said flash vessel is maintained at a value below the pressure prevailing above said packed column
Data Source
AI summary
A process for the physical refining of edible oils and fats, said process comprising three consecutive stages, whereby in a first stage at least 60% by weight of the volatiles are evaporated in a flash vessel, in a second stage some residual volatiles are evaporated by countercurrent steam stripping using a packed column (3), and in a third stage further residual volatiles are evaporated in a cross-flow tray system (2), wherein the pressure in said flash vessel is maintained at a value below the pressure prevailing above said packed column (3); and an apparatus for the physical refining of edible oils and fats comprising a flash vessel, a packed column (3), sparging trays (2) and the means to maintain the pressure in said flash vessel at a value that is below the pressure prevailing above said packed column.