Polysiloxane-Coated Oxide Membranes for High-Temperature Nanofiltration
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Solution Overview
Problem
Existing nanofiltration membranes have limited flow rates and thermal stability, making them unsuitable for high-temperature applications in the petrochemical industry, and current attempts to enhance thermal stability often result in membrane failure or fracture.
Innovation Solution
A composite body with a porous substrate and oxide particle layers, topped with a polymer coating containing polysiloxanes, featuring uniform particle sizes and a smooth surface, enabling high flow rates and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nanofiltration is performed at higher temperatures (120-200°C) to increase flow rate, then productivity improves, but membrane materials lack sufficient thermal stability and fail or fracture
Solution Approach 1:
The patent uses a composite structure consisting of a porous substrate (ceramic or metal) coated with a polysiloxane-containing polymer layer. The substrate provides thermal stability and mechanical strength, while the polymer coating provides separation functionality. This composite approach allows the membrane to withstand temperatures up to 200°C while maintaining high flow rates, resolving the contradiction between productivity and thermal stability.
2Reliability
If thermally stable polymers are used to manufacture membranes, then thermal stability improves, but the porous support structure is compressed at elevated pressure and temperature causing membrane failure or fracture
Solution Approach 1:
The patent employs a porous substrate structure (ceramic or metal) that maintains its structural integrity at elevated temperatures and pressures. The porous nature allows fluid flow while the inorganic material resists compression and thermal degradation. The polymer coating is applied to the porous support, which prevents the coating from bearing the full mechanical load, thus avoiding compression-induced failure while maintaining thermal stability.
3Ease of manufacture
If known silicone-coated PAN membranes are used, then ease of manufacture improves, but the application window is limited to 20-40 bar and maximum temperature of 50°C
Solution Approach 1:
The patent changes the fundamental parameters of the membrane system by replacing the polyacrylonitrile (PAN) substrate with thermally stable ceramic or metal substrates and using polysiloxane-containing polymers instead of conventional silicone coatings. This parameter change expands the operational window from 50°C maximum to 200°C, and from 40 bar to potentially higher pressures, while maintaining ease of manufacture through established coating techniques.
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 body achieves flow rates greater than 200 GPU and thermal stability up to 200°C, allowing direct treatment of high-temperature streams without cooling, and is flexible for easy integration into industrial modules.
Implementation Method 1
a porous layer (1) composed of oxide particles bonded to one another and partly to the substrate
Implementation Method 2
a polymer coating (PB) containing one or more polysiloxanes is present atop or above layer (2)
Implementation Method 3
the use thereof, especially in organophilic nanofiltration
Data Source
AI summary
A composite body comprising a porous layer (1) made from oxide particles connected to one another and partially to a substrate, containing at least one oxide of the elements Al, Zr, Ti or Si, and comprising a further porous layer (2) at least on one side, having oxide particles connected to one another and partially to the layer (1) and containing at least one oxide of the elements Al, Zr, Ti or Si, wherein the oxide particles in the layer (1) have a greater average particle size (d50 is 0.5 to 4 μm) than the oxide particles in the layer (2) (d50 is 0.015 to 0.15 μm), characterised in that a polymer coating (PB) is provided on or above the layer (2), containing one or more polysiloxanes. A method for producing corresponding composite bodies and to the use thereof.