Ionic Liquid Recovery via Hydrocarbon Fractionation
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Solution Overview
Problem
Existing methods for recovering entrained ionic liquids from hydrocarbon conversion processes are costly and inefficient, particularly due to the need for coalescing materials and limited control over separation processes.
Innovation Solution
A method that increases the ionic liquid volume fraction in the hydrocarbon phase by fractionating and separating the hydrocarbon stream, allowing for coalescence of ionic liquid droplets without the use of coalescing materials, utilizing gravity separation and additional separation zones to recover the ionic liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional liquid-liquid phase separation by gravity is used, then the separation process is simple, but small droplets of ionic liquid remain entrained in the immiscible phase
Solution Approach 1:
The patent applies preliminary action by performing fractionation of the hydrocarbon phase before final ionic liquid recovery. The hydrocarbon phase is fractionated into at least two fractions, with the lighter fraction containing the entrained ionic liquid droplets. This preliminary separation concentrates the ionic liquid in a specific fraction, making subsequent recovery more effective and reducing overall entrainment losses.
2Loss of substance
If coalescing material is used to recover entrained ionic liquids, then ionic liquid recovery efficiency is improved, but process cost and device complexity increase
Solution Approach 1:
The patent extracts the ionic liquid recovery function from the traditional coalescing material approach. Instead of using external coalescing materials, the method utilizes the inherent fractionation process to separate and concentrate ionic liquid droplets in the lighter hydrocarbon fraction, followed by gravity separation. This eliminates the need for additional coalescing materials and associated equipment complexity.
Solution Approach 2:
The system performs self-service by using the existing fractionation process to achieve ionic liquid concentration and separation. The fractionation process itself, combined with gravity separation, provides the coalescing function without requiring external coalescing materials. The process leverages its own operational steps to achieve recovery, reducing external dependencies.
3Loss of substance
If additional ionic liquid is added to increase volume fraction, then ionic liquid recovery is improved, but process cost increases
Solution Approach 1:
The patent introduces the lighter hydrocarbon fraction as an intermediary medium. This fraction acts as a mediator that naturally concentrates ionic liquid droplets through the fractionation process. By directing the lighter fraction to a separate gravity separation zone, the system achieves ionic liquid concentration without adding more ionic liquid, using instead the intermediary hydrocarbon fraction as the concentration vehicle.
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 effectively recovers entrained ionic liquids with higher efficiency and reduced costs by leveraging existing process conditions, enhancing collision frequency and coalescence of droplets, and allowing for their separation through gravity or other methods.
Implementation Method 1
separating the process stream comprising a mixture of hydrocarbons and ionic liquid into an ionic liquid phase and a hydrocarbon phase in a gravity separation zone
Implementation Method 2
flashing at least a portion of the process stream comprising a mixture of hydrocarbons and ionic liquid into a vapor phase comprising a first portion of at least one first hydrocarbon and a liquid phase comprising a second portion of the at least one first hydrocarbon
Implementation Method 3
coalescing ionic liquid droplets onto a coalescing material, coalescing the small droplets into larger droplets
Data Source
AI summary
Methods of recovering droplets of ionic liquid catalyst from a process stream are described. The volume fraction of ionic liquid in the hydrocarbon is increased to cause the ionic liquid droplets to coalesce. One method incorporates various combinations of gravity separation zone(s) and fractionation zones. Another method involves using a combination of a flash vessel and a fractionation zone, as well as an optional gravity separation zone.