High Emissivity Coating Composition for Fired Heaters
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Solution Overview
Problem
Current high emissivity coating compositions, particularly those using silicon carbide, degrade in mechanical strength and performance at high temperatures, leading to inefficiencies in fired heaters and furnaces.
Innovation Solution
A thermal emissivity coating composition comprising 30-65% emissivity agents, 10-35% fillers like aluminum and silicon oxides, and 12-52% binder, with cobalt and chromium oxides, applied to substrates and heat-treated for enhanced durability and emissivity at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon carbide is used as an emissivity agent in high temperature applications, then emissivity enhancement is achieved at moderate temperatures, but mechanical strength and emissivity degrade substantially over time
Solution Approach 1:
The patent changes the chemical composition parameters by replacing silicon carbide with specific metal oxides (cobalt oxide 10-25 wt%, chromium oxide 5-10 wt%, titanium oxide 13-30 wt%) that maintain stability at high temperatures up to 1500°C, thereby improving coating durability without sacrificing mechanical strength
Solution Approach 2:
The patent creates a composite coating material combining multiple oxide components (cobalt oxide, chromium oxide, titanium oxide, aluminum oxide, silicon oxide) with a binder, where each component contributes specific properties that collectively enhance both reliability and mechanical strength at high temperatures
2Loss of energy
If high emissivity coatings are applied to increase radiant heat transfer, then energy efficiency improves, but coating adhesion and lifetime may be compromised
Solution Approach 1:
The patent uses oxide-based emissivity agents that are inherently stable and resistant to degradation at high temperatures, replacing shorter-lived materials like silicon carbide, thereby extending coating lifetime while maintaining energy efficiency benefits
Solution Approach 2:
The composite formulation combining multiple stable oxides with appropriate binders creates a durable coating system that maintains both high emissivity for energy efficiency and extended service life through resistance to thermal degradation
3Power
If emissivity agents are added to enhance radiant heat transfer, then thermal efficiency increases, but coating adhesion on substrates deteriorates
Solution Approach 1:
The patent formulates a composite coating system where oxide emissivity agents are combined with binders and fillers in specific proportions, creating a cohesive material structure that adheres well to substrates while maintaining high radiant heat transfer capability
Solution Approach 2:
The patent optimizes the local composition and distribution of different oxide components and binder phases within the coating matrix, ensuring proper adhesion at the coating-substrate interface while maintaining emissivity enhancement in the coating bulk
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 coating composition maintains high emissivity and mechanical strength at temperatures up to 1500°C, preventing cracking and delamination, and offering excellent thermal spalling resistance through the use of cobalt, chromium, and titanium oxides with a binder like phosphoric acid.
Implementation Method 1
emissivity (symbolically represented as s or e) can be broadly defined as the relative ability of a surface to emit energy by radiation
Implementation Method 2
a binder in an amount from 12 to 52 wt %
Data Source
AI summary
The present invention relates to a thermal emissivity coating composition comprising: a) an emissivity agent in an amount from 30 to 65% by weight with respect to the total weight of the thermal emissivity coating composition; b) a filler selected from the group consisting of oxides of aluminum, silicon, magnesium, calcium, boron and mixtures of two or more thereof, in an amount from 10 to 35 wt % with respect to the total weight of the thermal emissivity coating composition; and c) a binder in an amount from 12 to 52 wt % with respect to the total weight of the thermal emissivity coating composition; wherein the emissivity agent comprises cobalt oxide in an amount from 10 to 25 wt %, preferably 12 to 25 wt % with respect to the total weight of the thermal emissivity coating composition and further comprises chromium oxide and titanium oxide.