Polyurethane/PVDF Composite Membrane for Naphtha Desulfurization
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Solution Overview
Problem
Traditional methods for extracting organic sulfide from naphtha, such as hydrodesulfurization, are costly and complex, and existing membrane technologies suffer from low permeation flux, limiting extraction efficiency.
Innovation Solution
A polyurethane/polyvinylidene fluoride composite membrane is developed, comprising a polyurethane active layer and a polyvinylidene fluoride support layer, prepared through specific coating and drying processes, which enhances the extraction efficiency of organic sulfide from naphtha without chemical reactions or pretreatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyurethane membrane is used to extract organic sulfide from naphtha, then chemical stability and solvent resistance are improved, but permeation flux is reduced
Solution Approach 1:
The patent creates a composite membrane structure where polyurethane forms the active layer (20-30 μm thick) providing chemical stability and sulfide selectivity, while polyvinylidene fluoride forms the support layer (110-120 μm thick) providing mechanical strength and permeability. This composite structure allows the membrane to simultaneously achieve high chemical stability from polyurethane and high permeation flux from the porous PVDF support layer, resolving the contradiction between reliability and productivity.
2Quantity of substance
If traditional hydrodesulfurization is used to treat organic sulfide, then sulfide removal is achieved, but process complexity and operational costs increase
Solution Approach 1:
The patent extracts and isolates the sulfide removal function into a simple membrane separation process. The pervaporation membrane directly separates organic sulfides from naphtha based on permeation differences, eliminating the need for complex hydrodesulfurization reactors, catalysts, hydrogen supply systems, and tail gas treatment facilities. This extraction approach achieves high sulfide removal efficiency while dramatically simplifying the overall process structure and reducing operational complexity.
Solution Approach 2:
The patent replaces the complex chemical reaction-based hydrodesulfurization system with a physical membrane separation system. Instead of using catalysts, high pressure hydrogen, and complex reaction conditions, the invention uses the inherent permeation properties of the polyurethane/PVDF composite membrane to separate sulfides from naphtha through a simple pressure-driven pervaporation process, substituting mechanical/physical separation for chemical reaction-based treatment.
3Strength
If membrane thickness is increased to improve mechanical strength, then structural stability is improved, but permeation flux is reduced
Solution Approach 1:
The patent segments the membrane into two distinct functional layers with different thicknesses and properties: a thin active layer (20-30 μm) of polyurethane that provides separation selectivity and chemical stability, and a thick support layer (110-120 μm) of polyvinylidene fluoride that provides mechanical strength and structural stability. This segmentation allows each layer to be optimized for its specific function, with the thin active layer maximizing permeation flux while the thick support layer ensuring mechanical integrity, thereby resolving the contradiction between strength and productivity.
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 composite membrane achieves high separation efficiency, extracting at least 80% of organic sulfide with minimal impact on the raw material oil's octane number, under mild conditions, and maintains performance over extended use.
Implementation Method 1
the active layer is polyurethane casting membrane... the composite membrane achieves high separation efficiency, extracting at least 80% of organic sulfide
Implementation Method 2
Polyurethane has properties of strong chemical stability, strong solvent resistance, strong hydrophobicity and good organophilicity... the composite membrane achieves high separation efficiency, extracting at least 80% of organic sulfide
Data Source
AI summary
The present invention relates to the field of composite membrane and discloses a polyurethane/polyvinylidene fluoride composite membrane for extracting organic sulfide from naphtha. The polyurethane/polyvinylidene fluoride composite membrane includes an active layer and a support layer where the active layer is a polyurethane casting membrane and the support layer is a polyvinylidene fluoride membrane. The polyurethane/polyvinylidene fluoride composite membrane is prepared by coating the active layer onto the support layer. At the same time, a preparation method for the polyurethane/polyvinylidene fluoride composite membrane is disclosed. The present invention has the following beneficial effects: the polyurethane/polyvinylidene fluoride composite membrane prepared in the present invention may be used to extract organic sulfide in naphtha with high separation efficiency. Further, the composite membrane almost does not change the octane number and the like of the raw material oil, thereby improving the extraction rate of the organic sulfide.