Liquid Impregnated Surface for Cryogenic Anti-Icing
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Solution Overview
Problem
Current ice-phobic surfaces can only prevent ice formation as low as −30° C, which is insufficient for applications such as natural gas liquefaction and CO2 removal from gas streams, leading to costly solutions for preventing heat exchanger plugging and safety issues.
Innovation Solution
A liquid impregnated surface (LIS) using a low viscosity hydrocarbon, such as polyalphaolefin (PAO) or heptane, with an ice formation temperature below −85° C, where the surface is configured to retain the liquid and prevent ice formation through textured or chemically functionalized surfaces, and indexed using a Liquid Index Number (LI) that relates hydrophobicity to viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional liquid impregnated surfaces are used, then ice formation is prevented down to −30° C, but this is insufficient for applications requiring lower temperatures such as natural gas liquefaction and CO2 removal
Solution Approach 1:
The patent changes the physical parameters of the impregnating liquid by selecting low viscosity hydrocarbons (viscosity < 500 mPa·s at 25°C) with specific molecular structures. This parameter change enables the surface to maintain liquid impregnation at cryogenic temperatures down to −85° C or lower, resolving the contradiction between achieving lower ice formation temperatures and maintaining reliability for LNG generation and CO2 removal applications
Solution Approach 2:
The patent employs composite material strategy by combining textured or porous surface structures with specifically selected low viscosity hydrocarbon liquids (such as polyalphaolefin or heptane). This composite approach creates a synergistic effect where the surface structure provides mechanical retention while the low viscosity hydrocarbon provides thermal stability and ice phobicity at ultra-low temperatures, achieving both extended temperature range and application reliability
2Quantity of substance
If frozen material is removed from gas streams by chilling, then water and CO2 can be removed, but the frozen material adheres to heat exchanger surfaces and plugs tubes
Solution Approach 1:
The patent converts the harmful effect of frozen material adhesion into a beneficial anti-icing surface. By impregnating heat exchanger surfaces with low viscosity hydrocarbons, the normally harmful ice formation is transformed into a controlled liquid impregnated layer that actually prevents ice adhesion. The frozen water and CO2 that would normally plug tubes are now repelled by the ice-phobic surface, allowing continuous operation without plugging while maintaining effective dehydration and CO2 removal
Solution Approach 2:
The low viscosity hydrocarbon liquid acts as an intermediary substance between the heat exchanger surface and the frozen water/CO2. This intermediary layer prevents direct contact and adhesion between ice and the heat exchanger tubes, allowing frozen material to be removed from gas streams through chilling without causing the harmful plugging and adhesion problems that conventional systems experience
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 solution effectively reduces ice formation temperature by 35° C or more, providing superior anti-icing properties for applications like LNG generation, cryogenic dehydration, and heat exchanger systems, preventing ice formation and hydrate formation, thus improving operational efficiency and safety.
Implementation Method 1
a textured surface and/or a porous surface and/or a surface with a high surface area to volume ratio
Implementation Method 2
the liquid is a low viscosity hydrocarbon... the low viscosity hydrocarbon can have an ice formation temperature of below about 215 K (−58.15 degrees C.)
Data Source
AI summary
A structure for use as a liquid impregnated surface (LIS) can include a surface configured to interact with a liquid to retain the liquid to the surface. The liquid can be a low viscosity hydrocarbon. In certain embodiments, the low viscosity hydrocarbon can be polyalphaolefin (PAO) or heptane, for example. Any other suitable low viscosity hydrocarbon is contemplated herein. In certain embodiments, the structure can further include the low viscosity hydrocarbon disposed on the surface.