Extractive Distillation Column Feed Pipe Venturi Mixing
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Solution Overview
Problem
Existing extractive distillation columns suffer efficiency losses due to incomplete mixing of reflux and selective solvent, particularly in larger diameters, leading to reduced separation efficiency and increased installed height when attempting to improve mixing.
Innovation Solution
A column design featuring a first, substantially horizontal feed pipe with a cross-sectional narrowing and widening, where the reflux is aspirated into the solvent using the Venturi effect, eliminating the need for additional height or moving parts, and optionally incorporating a static mixing element for enhanced mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If separate supply of reflux and selective solvent is used, then device complexity is reduced, but mixing efficiency deteriorates causing efficiency losses of up to 60%
Solution Approach 1:
The patent merges the reflux and selective solvent supply streams by introducing the reflux into the selective solvent feed pipe at the narrowest point, combining two separate supply functions into a single integrated flow path that ensures thorough mixing before the liquids enter the separatory internals
Solution Approach 2:
The patent performs preliminary mixing of reflux and selective solvent in the feed pipe before the liquids reach the separatory internals, using the Venturi effect to create turbulence and homogenize the mixture in advance, so that the separatory internals are fully available for the separation task
2Productivity
If two liquid distributors are disposed above one another to improve mixing, then mixing efficiency is improved, but installed height increases
Solution Approach 1:
The patent transitions from a vertical mixing approach (using multiple distributors at different heights) to a horizontal mixing approach (using a side-entry feed pipe configuration), achieving thorough mixing within the same vertical space without increasing column height
3Productivity
If an admixing apparatus is used to mix reflux and selective solvent, then mixing efficiency is improved, but device complexity increases
Solution Approach 1:
The patent employs the Venturi effect to enable the selective solvent stream itself to aspirate and mix the reflux stream, using the flow dynamics of the selective solvent to create the mixing action without requiring external pumps, motors, or complex mechanical admixing devices
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 configuration ensures thorough and efficient mixing of reflux and selective solvent, maintaining column efficiency without increasing height, even for large diameters, and improves separation outcomes for mixtures like butanes and butenes with N-methylpyrrolidone.
Implementation Method 1
the first, substantially horizontal feed pipe exhibits a cross-sectional narrowing to a narrowest point, said pipe widening again downstream of the cross-sectional narrowing... the suction effect of the liquid jet of the selective solvent which flows in through the first, substantially horizontal feed pipe
Implementation Method 2
The gas that has already been aspirated is completely dissolved in the liquid due to the high turbulences downstream of the narrowest point of the cross-sectional narrowing
Data Source
AI summary
What is proposed is a column (K) comprising separatory internals (E) for separating a mixture of hydrocarbons and/or hydrocarbon derivatives (1) by extractive distillation with a selective solvent (2),with supply of the selective solvent (2) in the upper region of the column and supply of the mixture of hydrocarbons and/or hydrocarbon derivatives to be separated (1) below the supply of the selective solvent (2), the selective solvent (2) becoming laden in the column (K) with the components from the mixture to be separated (1) for which it has greater affinity and being withdrawn from the lower region of the column as laden selective solvent (3),while, by contrast, the components from the mixture to be separated for which the selective solvent (2) has a lower affinity remain in the vapor phase and are withdrawn as top stream (4),which is completely or partially condensed to obtain a condensate (5),some of which is withdrawn as product stream (6), the remainder being reintroduced to the column (K) as reflux (7),whereinsaid column comprises in the region of the column above the separatory internals (E) a first, substantially horizontal feed pipe (R1) for supplying the selective solvent,wherein the first, substantially horizontal feed pipe (R1) exhibits a cross-sectional narrowing to a narrowest point (V), said pipe widening again downstream of the cross-sectional narrowing, and whereinsaid column comprises a second feed pipe (R2) for supplying the reflux (7), said pipe joining the first, substantially horizontal feed pipe (R1) in the region of the narrowest point (V) of the cross-sectional narrowing.