Microchannel Heater with Layered Combustion Plates
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Solution Overview
Problem
Conventional reactors for uniform heating in steam reforming reactions face challenges in maintaining high temperature efficiency and uniformity, leading to non-uniform combustion and reduced catalyst activity due to limited heat transfer and temperature differences.
Innovation Solution
A microchannel heater design with alternately layered combustion and heat transfer plates, featuring microchannels coated with oxidation catalysts and hydrocarbon reforming catalysts, facilitates uniform mixing of fuel and air to maximize heat transfer and minimize temperature differences across the reactor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the temperature of the flame is increased to obtain the temperature difference for heat transfer, then the heat transfer efficiency is improved, but the constituent material becomes degraded and nitrogen oxide pollutants are generated
Solution Approach 1:
The reactor is divided into multiple thin metal plates with microchannels, creating distributed combustion zones throughout the reactor volume. This segmentation allows combustion to occur at many points simultaneously, achieving uniform heating without requiring excessive temperature at any single location, thereby preventing material degradation and NOx generation while maintaining efficient heat transfer.
Solution Approach 2:
The invention transitions from conventional single-zone combustion to multi-zone distributed combustion by stacking multiple plates with microchannels. This dimensional transformation from 1D to 3D combustion distribution enables uniform heat generation throughout the reactor, improving heat transfer efficiency without the harmful effects of high-temperature concentrated flames.
2Area of stationary object
If a reactor with microchannels is used to increase heat transfer area, then the contact area is increased, but non-uniform combustion occurs leading to non-uniform temperature distribution and decreased catalyst activity
Solution Approach 1:
Different regions of the reactor are designed with specific functions: some microchannels are optimized for fuel-oxidant mixing and combustion, while adjacent channels are optimized for heat transfer and catalyst contact. This local differentiation ensures that combustion occurs uniformly across all regions, preventing hot spots and maintaining consistent catalyst activity throughout the reactor.
Solution Approach 2:
The reactor is segmented into multiple functional zones across stacked plates, with each plate containing microchannels for specific purposes (combustion, heat transfer, catalyst support). This segmentation distributes the combustion process uniformly across the entire heat transfer area, eliminating non-uniform temperature distribution and maintaining optimal catalyst activity throughout.
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 microchannel heater achieves uniform heating and increased efficiency by promoting combustion reactions at multiple points within the reactor, reducing temperature differences and enhancing catalyst activity.
Implementation Method 1
The microchannels of the combustion plates are coated with an oxidation catalyst, such as any of Al, Ti, Si, and Zr
Implementation Method 2
The combustion plate has a fuel supply hole connected to a fuel hole of an adjacent heat transfer plate. The microchannels of the combustion plates are coated with an oxidation catalyst
Implementation Method 3
The microchannels of the heat transfer plates are coated with a hydrocarbon reforming catalyst that preferably includes a precious metal
Implementation Method 4
CH4+H2O→CO+3H2,H2980=+206 kJ/mol Reaction 1
Implementation Method 5
A plurality of combustion plates and a plurality of heat transfer plates are alternately layered between the upper plate and the lower plate
Implementation Method 6
A second plurality of microchannels connect the inlet hole of material to be heated and the heated material outlet hole of the heat transfer plate
Data Source
AI summary
A heater has microchannels for uniform heating, and includes an upper plate having an inlet of material to be heated, a fuel inlet and an oxidant inlet. A lower plate has a heated material outlet and an exhaust gas outlet. A plurality of combustion thin plates and a plurality of heat transfer thin plates are alternately layered between the upper and lower plates. Each of the combustion thin plates and the heat transfer thin plates has an inlet hole of material to be heated, a heated material outlet hole, an oxidant hole, an exhaust gas hole, a fuel hole, and microchannels formed at respective corresponding positions. The upper plate is aligned with the combustion thin plate contacting the lower surface thereof, and the lower plate is aligned with the heat transfer thin plate contacting the upper surface thereof.