Wire-Matrix Heat Exchange Reactor for Hotspot and Coke Reduction
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Solution Overview
Problem
Existing shell-and-tube reactors face issues with undesirable temperature profiles, coke formation, and frequent maintenance due to poor heat transfer and catalyst deactivation, leading to reduced selectivity and operational inefficiencies.
Innovation Solution
A shell-and-tube heat exchange reactor with a reactant pre-heating zone and a catalytically active wire matrix insert in the reaction zone, which facilitates efficient heat transfer and minimizes catalyst deactivation by maintaining optimal reaction temperatures and reducing coke formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional fixed bed catalysts are used in shell-and-tube reactors, then catalytic activity is achieved, but temperature profile control deteriorates leading to hotspots and poor selectivity
Solution Approach 1:
The patent employs a porous catalyst support structure with controlled porosity to enhance heat transfer from the catalyst interior to the exterior. The porous structure allows efficient heat dissipation while maintaining catalytic activity, preventing hotspots and improving temperature profile control throughout the catalyst bed.
Solution Approach 2:
The patent uses composite catalyst materials consisting of active catalytic components supported on thermally conductive materials. This composite structure combines high catalytic activity with improved thermal conductivity, enabling better heat transfer and temperature control while maintaining or enhancing selectivity.
2Power
If exothermic catalytic reactions are performed in conventional reactors, then reaction rate increases, but heat transfer efficiency deteriorates causing runaway reactions
Solution Approach 1:
The patent utilizes the thermal expansion properties of the catalyst support structure to create controlled void spaces that facilitate heat transfer. The expansion creates channels for heat dissipation while maintaining structural integrity and catalytic activity.
Solution Approach 2:
The patent segments the catalyst bed into smaller functional units with improved heat transfer interfaces. This segmentation allows better heat removal from each segment, preventing thermal runaways while maintaining overall high reaction rates through optimized heat and mass transfer.
3Ease of manufacture
If conventional catalyst filling methods are used, then catalyst installation is completed, but operational complexity increases due to filling level measurement requirements
Solution Approach 1:
The patent employs a self-leveling catalyst support structure that automatically achieves the correct filling level without requiring external measurement or control systems. The structure's geometry and fluid dynamics properties enable automatic leveling, eliminating the need for complex filling level measurement and control equipment.
4Productivity
If catalysts operate for extended periods, then productivity increases, but catalyst deactivation worsens due to coke formation
Solution Approach 1:
The patent maintains continuous optimal heat transfer conditions throughout catalyst operation, preventing the thermal conditions that lead to coke formation. This continuous effective heat management allows the catalyst to operate at high productivity for extended periods without deactivation.
Solution Approach 2:
The patent modifies physical parameters of the catalyst support structure, such as porosity and thermal conductivity, to create conditions that prevent coke formation. These parameter changes enable the catalyst to maintain high activity and selectivity over extended operational periods by eliminating the thermal and chemical conditions that cause deactivation.
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 reactor design enhances selectivity and reduces maintenance frequency by ensuring uniform temperature distribution and minimizing catalyst deactivation, thereby increasing operational hours and utilizing production capacity effectively.
Implementation Method 1
a shell-side heat exchange passage for circulating a heat transfer medium
Implementation Method 2
a catalytically active wire matrix insert having at least on a part of its surface a catalytically active precious metal
Implementation Method 3
a reactant pre-heating zone adjacent to the inlet, and a reaction zone downstream of the reactant pre-heating zone
Data Source
AI summary
A shell-and-tube heat exchange reactor for carrying out a catalytic gas-phase partial oxidation reaction comprises a shell-side heat exchange passage for circulating a heat transfer medium and a reaction passage comprising a plurality of reaction tubes; an inlet for introducing the reactant stream to the reaction passage; and an outlet from the reaction passage for recovering an effluent stream from the reaction tubes. The reaction tubes comprise a reactant pre-heating zone adjacent to the inlet, and a reaction zone downstream of the reactant pre-heating zone, the reaction zone having a catalytically active wire matrix insert having at least on a part of its surface a catalytically active precious metal. The reactor requires less frequent maintenance in the form of regeneration and/or replacement of the catalyst. The catalyst can be easily placed into the reaction tubes, and be removed therefrom. Only the portion of the entire reactant stream that travels near the hot reaction tube wall is heated up. Consequently, the portion of the reactant stream flowing in the center of the reaction tube is not heated to the reaction temperature and blind reactions of the unstable starting materials are thus reduced or even avoided.