Fiber-Reinforced Refractory Lining for Low-Coke Hydrocarbon Vessels
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Solution Overview
Problem
Hydrocarbon conversion processes face significant challenges due to metal catalyzed coke (MCC) formation, which leads to premature equipment failure, reduced efficiency, and increased maintenance costs, particularly at high temperatures and pressures, despite existing methods like antifoulants and sulfur inhibitors having limited success.
Innovation Solution
A refractory lining comprising a refractory material with reinforcement metallic fibers containing specific compositions of aluminum, chromium, and iron is used to mitigate MCC formation, providing enhanced carburization resistance and durability under severe hydrocarbon processing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If process temperatures are increased to achieve efficient conversion rates and desired hydrocarbon products, then productivity and conversion efficiency are improved, but metal catalyzed coke formation increases leading to heat transfer reductions and pressure drops
Solution Approach 1:
A refractory lining is introduced as an intermediary barrier between the hydrocarbon process stream and the metal alloy reactor surfaces. The refractory material prevents direct contact between hydrocarbons and metal surfaces, eliminating the catalytic effect that leads to coke formation while allowing the process to operate at high temperatures for improved productivity
Solution Approach 2:
The reactor lining uses composite refractory materials that combine multiple components with complementary properties. These composite materials provide both thermal stability for high-temperature operation and resistance to coke formation, allowing simultaneous achievement of high productivity and reduced harmful coking effects
2Object-affected harmful factors
If sulfur compounds are added to inhibit metal catalyzed coke formation, then coke deposits are reduced, but sulfidation attack of the metal surfaces increases causing corrosion and reduced equipment life
Solution Approach 1:
The refractory lining serves as an intermediary barrier that eliminates the need for sulfur compounds as coke inhibitors. By preventing direct contact between hydrocarbons and metal surfaces, the refractory lining stops coke formation without introducing sulfidation corrosion, resolving the contradiction between coke inhibition and metal protection
Solution Approach 2:
The harmful metal surfaces are extracted from the process stream environment by covering them with refractory material. This removes the source of both coke formation and susceptibility to sulfidation, eliminating the need to add sulfur compounds and avoiding the associated corrosion problems
3Reliability
If higher-grade expensive metallurgy is used to resist coke formation, then durability and resistance to coking are improved, but device complexity and cost increase
Solution Approach 1:
A refractory lining acts as an intermediary protective layer between the process stream and the metal reactor walls. This allows the use of simpler, less expensive metal alloys since the refractory material bears the brunt of coke-resistant properties, reducing device complexity and cost while maintaining reliability
Solution Approach 2:
The system uses composite construction with refractory lining over metal substrates. The refractory component provides coke resistance while the metal provides structural strength, achieving high reliability without requiring complex high-grade metallurgy throughout the entire device
4Reliability
If refractory lining with metallic fibers is used to protect against coke formation, then resistance to carburization and durability are improved, but the complexity of the lining structure increases
Solution Approach 1:
The refractory lining uses composite materials that inherently provide carburization resistance. By selecting refractory compositions with appropriate chemical stability and incorporating metallic fibers during manufacturing, the lining achieves high durability without requiring complex multi-layer structures or additional protective systems
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 refractory lining significantly reduces coke formation and maintains structural integrity, allowing hydrocarbon conversion processes to operate at higher severity conditions with improved equipment lifespan and efficiency.
Implementation Method 1
A refractory lining comprising a refractory material with reinforcement metallic fibers containing specific percentages of aluminum, chromium, and iron is introduced to mitigate coke formation
Implementation Method 2
providing improved carburization resistance and durability under severe hydrocarbon processing conditions
Data Source
AI summary
A hydrocarbon conversion process is disclosed. The process introduces a feed stream comprising hydrocarbons into a vessel having a refractory lining. The refractory lining comprises a refractory material and reinforcement metallic fibers. The reinforcement metallic fibers comprise about 0.5 wt % to about 8 wt % aluminum, 10 wt % to about 35 wt % chromium, and no less than about 50 wt % iron. The hydrocarbons are converted in the vessel at conversion conditions with or without a catalyst to yield a product stream.