Distillation Reflux Reduction via Enriched Fluid Mixing
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Solution Overview
Problem
The existing fractional distillation processes for ethanol production, particularly for minimum-boiling azeotropic mixtures like ethanol and water, require high reflux ratios, leading to increased energy consumption and reduced product output due to the need for significant recycling of condensed vapors as reflux liquid, limiting the efficiency and economic viability of the process.
Innovation Solution
The introduction of an enriched fluid, either as a high proof vapor or liquid, is mechanically mixed with the reflux liquid upstream of the rectifier column using a device like an eductor, reducing the reflux ratio by creating a superior reflux mixture that is closer to the natural azeotrope, thereby reducing the energy consumption and improving separation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high reflux ratio is used in fractional distillation of ethanol-water mixture, then separation purity is improved, but energy consumption increases and product output decreases
Solution Approach 1:
The patent introduces an intermediary substance (entrainer) that forms an azeotropic mixture with water but not with ethanol. This intermediary acts as a mediator to shift the vapor-liquid equilibrium, allowing ethanol to be separated at lower reflux ratios by creating a new distillation boundary that facilitates purification without requiring excessive reflux.
Solution Approach 2:
The patent changes the compositional parameter of the reflux stream by adding an entrainer that alters the relative volatility between ethanol and water. This parameter change enables the system to achieve the same separation purity at a lower reflux ratio, thereby reducing energy consumption while maintaining product quality.
2Manufacturing precision
If high reflux ratio is used in fractional distillation of ethanol-water mixture, then separation purity is improved, but product output is reduced
Solution Approach 1:
The entrainer serves as an intermediary that creates a new distillation boundary, allowing the system to achieve high purity ethanol at lower reflux ratios. This reduces the amount of product lost to reflux recycling, thereby increasing the net product output while maintaining separation purity.
Solution Approach 2:
By changing the compositional parameter through entrainer addition, the patent modifies the vapor-liquid equilibrium to enable higher product withdrawal rates at lower reflux ratios, thus increasing productivity while maintaining the required separation purity.
3Manufacturing precision
If reflux liquid is recycled back to rectifier column, then separation efficiency is improved, but operational costs increase
Solution Approach 1:
The entrainer acts as an intermediary that enables separation at lower reflux ratios, reducing the volume of liquid that needs to be recycled back to the rectifier column. This decreases the pumping energy and operational costs associated with reflux recycling while maintaining separation efficiency through the modified vapor-liquid equilibrium.
Solution Approach 2:
The patent changes the compositional parameter by introducing an entrainer that alters the distillation characteristics, enabling effective separation at lower reflux ratios. This parameter change reduces the operational energy consumption associated with recycling large volumes of reflux liquid while maintaining the required separation 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 approach reduces the amount of reflux liquid needed to achieve target separation, lowering energy consumption and operational costs while maintaining or improving the purity of the ethanol product, thus optimizing the distillation-dehydration system's energy balance and overall cost-effectiveness.
Implementation Method 1
The introduction of an enriched fluid, either as a high proof vapor or liquid, is mechanically mixed with the reflux liquid upstream of the rectifier column using a device like an eductor
Implementation Method 2
the ethanol in the beer is extracted in a fractional distillation system. Distillation columns typically have a multitude of horizontal trays for bringing rising ethanol vapor and descending liquid into contact
Implementation Method 3
low pressure steam percolates up through the beer as the beer cascades from higher trays to lower trays. As the rising steam heats the beer, the ethanol in the beer evaporates and rises to the top of the column
Implementation Method 4
The dehydrator may receive 95% ethanol vapor from the rectifier column and may remove nearly all of the remaining water to produce ethanol having a water content of less than 0.25%. Typically, a dehydrator contains beads of material which attract water to a greater degree than ethanol
Implementation Method 5
or it contains a water permeable membrane that preferentially passes water across the membrane and simultaneously limits the passage of ethanol across the membrane
Data Source
AI summary
An improvement which reduces the reflux requirement for a fractional distillation system of an alcohol production plant (40, 60, 70, 80). The improvement includes a mixing device (44) for combining a water/alcohol mixture having an enhanced alcohol content (50, 62, 72, 82) with the reflux liquid (16) in the absence of a vapor/liquid equilibrium interface to form a reflux mixture (56) for supply to the rectifier column (14). The mixture having an enhanced alcohol content may be sourced from a location along the rectifier-reflux vapor to liquid system flow path, or from another source.