Facilitated Transport Membrane for Aromatic Separation
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Solution Overview
Problem
Current methods for separating aromatics from hydrocarbon streams in petroleum refineries are costly and energy-intensive, and conventional membrane pervaporation processes suffer from low selectivity and flux rates, limiting their commercial viability.
Innovation Solution
A facilitated transport membrane (FTM) is developed using a hydrophilic polymer matrix with complexing agents like silver salts incorporated into polyvinyl alcohol and sodium alginate, enhancing selectivity and flux rates by selectively interacting with aromatics, and is combined with an extractive distillation process for improved separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional membrane pervaporation processes are used, then membrane separation is achieved, but selectivity and flux rate are low (selectivity 5-20, flux rate 0.03-0.3 kg/m2/h)
Solution Approach 1:
The patent employs composite membrane materials combining polyvinyl alcohol (PVA) and sodium alginate (SA) matrices with silver nitrate complexing agents. This composite structure achieves both high selectivity (40-80) and improved flux rates (0.5-2.0 kg/m2/h) by integrating the selective binding capability of silver salts with the structural properties of hydrophilic polymers, resolving the trade-off between selectivity and productivity
Solution Approach 2:
The patent modifies membrane parameters by incorporating different concentrations of complexing agents (silver nitrate at 5-20 wt%) and adjusting polymer composition ratios (PVA:SA from 9:1 to 1:9). These parameter changes enable optimization of both selectivity and flux rate, achieving simultaneous improvement in separation performance and productivity
2Manufacturing precision
If liquid/liquid extraction or extractive distillation is used, then aromatic separation is achieved, but the process is costly and energy-intensive with high capital investment
Solution Approach 1:
The patent replaces energy-intensive mechanical separation processes (distillation columns requiring heat input and large reflux ratios) with a membrane-based separation system that operates at ambient or mild conditions. The facilitated transport membrane achieves high separation efficiency through selective molecular recognition by complexing agents, eliminating the need for high energy input while maintaining effective aromatic separation
3Reliability
If conventional polymeric membranes are used, then membrane separation is achieved, but strength and stability are insufficient
Solution Approach 1:
The patent creates composite membranes by integrating silver nitrate complexing agents within the PVA-SA polymer matrix. This composite structure enhances both mechanical strength and chemical stability compared to conventional polymeric membranes, while the cross-linked network formed by the polymer blend provides structural integrity and operational stability
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 FTM achieves significantly higher selectivity and flux rates compared to conventional membranes, reducing energy consumption and costs associated with aromatic separation, making the process more economical and effective.
Implementation Method 1
incorporating complexing agents (i.e., carriers that exhibit a strong affinity for aromatics) on to the backbone or membrane matrix of a polymeric hydrophilic membrane, such that the complexing agents selectively interact with aromatics in the hydrocarbon feed
Implementation Method 2
Membrane pervaporation processes have been used to separate various types of hydrocarbons
Data Source
AI summary
Certain embodiments of the invention provide an apparatus for separating aromatic hydrocarbons from an aromatic hydrocarbon feed stream. The apparatus includes a membrane support, and a hydrophilic polymer membrane matrix disposed on the membrane support. The hydrophilic polymer membrane matrix includes an effective amount of polyvinyl alcohol and an effective amount of sodium alginate. The apparatus further includes a carrier agent bonded to the hydrophilic polymer membrane matrix using a cross-linking agent. The carrier agent exhibits a greater affinity for aromatics compared to aliphatics. The apparatus further includes a membrane housing configured to hold the membrane support. The membrane housing includes an inlet, a permeate outlet, and a retentate outlet, the inlet being operable to receive the aromatic hydrocarbon feed stream, the permeate outlet being operable to discharge a permeate stream, and the retentate outlet being operable to discharge a retentate stream.