Pyrolysis Coil Porous Ceramic Packing for Heat Transfer and Coke Reduction
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Solution Overview
Problem
Pyrolysis coils face inefficiencies in heat transfer and coke deposition, leading to reduced selectivity and output of olefins due to coke buildup and pressure increases, necessitating frequent shutdowns for decoking.
Innovation Solution
Randomly packing at least part of the cylindrical passes in pyrolysis coils with thermally conductive filler materials, such as ceramics, to enhance heat transfer and reduce coke deposition, allowing for longer run lengths and improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If finned radiant tubes are used in a pyrolysis heater, then heat transfer is improved, but coke deposition increases leading to frequent shutdowns
Solution Approach 1:
The patent applies porous ceramic packing materials within the coil structure. These porous materials provide high surface area for heat transfer while their chemical inertness and thermal stability prevent coke adhesion, thereby maintaining heat transfer efficiency without the harmful side effect of increased coke deposition that plagues conventional finned tubes
Solution Approach 2:
The patent employs composite structures combining metal coils with ceramic packing materials. The metal provides structural integrity and thermal conductivity, while the ceramic filling provides high surface area for heat exchange and resistance to coke deposition, creating a synergistic system that resolves the contradiction between heat transfer efficiency and operational reliability
2Reliability
If ceramic coatings are applied to pyrolysis coils, then coke deposition is reduced, but heat transfer efficiency decreases
Solution Approach 1:
Instead of applying dense ceramic coatings that insulate and reduce heat transfer, the patent uses porous ceramic packing materials that provide both high heat transfer surface area and coke resistance. The porous structure allows thermal energy to pass through while the ceramic chemistry resists coke adhesion
Solution Approach 2:
The patent transitions from a two-dimensional surface coating approach to a three-dimensional packed bed structure. By filling the coil interior with porous ceramic particles, it creates a volumetric heat exchange medium that simultaneously achieves high heat transfer coefficients and coke resistance, overcoming the limitations of surface coatings
3Productivity
If coil operating time is extended, then productivity increases, but coke buildup increases leading to pressure drops
Solution Approach 1:
The porous ceramic packing material provides self-cleaning properties through its chemical inertness and surface characteristics that prevent coke adhesion. As hydrocarbons pass through the packed bed, coke precursors do not deposit on the ceramic surfaces, and any deposited coke can be easily removed by standard decoking procedures, enabling extended operational cycles without significant pressure drop increases
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 random packing increases the heat transfer coefficient, reduces coke production rates by 20-100%, and extends run lengths by 20-100% by minimizing coke buildup and maintaining low pressure drops, thereby enhancing olefin production efficiency.
Implementation Method 1
randomly packing at least part of at least one pass with a thermally conductive filler material
Implementation Method 2
heating the coils to a temperature sufficient to break down the hydrocarbon feedstock into olefins
Data Source
AI summary
Randomly packing with filler material at least part of a pass in a coil used in a system for pyrolyzing hydrocarbon feedstock to lighter hydrocarbons. Randomly packing increases heat transfer and decreases the rate of coke build-up within the coil, yielding an improvement in overall system efficiency. Packing material can comprise or be treated with a suitable catalyst for increasing the rate of chemical decomposition, thus further improving system efficiency.