Membrane Reactor Catalyst Granule Size for Thermal Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Membrane reactors face breakage issues due to differences in thermal expansion coefficients between catalysts and separation membranes, leading to stress and potential failure during temperature changes.
Innovation Solution
A membrane reactor design with a separation membrane complex and catalysts where the average granule diameter of the catalysts is between 0.75 and 1 times the inside diameter of the membrane-formed cells, and the cells have both longitudinal ends open, preventing stress-induced breakage by aligning catalysts to absorb thermal expansion stress along the cell length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If catalysts are filled in the cells of the separation membrane complex, then the chemical reaction efficiency is improved, but the separation membrane may break due to thermal expansion stress
Solution Approach 1:
The patent changes the physical parameter of catalyst granule size to resolve the contradiction. By setting the granule diameter to 0.5-2mm (optimally 0.8-1.5mm), the catalyst particles can effectively fill the cells and promote reaction while their discrete arrangement allows thermal expansion stress to be distributed and absorbed, preventing membrane breakage during temperature cycling between 150°C and 40°C
Solution Approach 2:
The patent applies local quality by creating a specific spatial arrangement where catalyst granules are distributed throughout the cell volume rather than concentrated in one location. This local distribution allows different regions to handle thermal stress differently, with the granule-membrane interface acting as a stress absorption zone that protects the membrane from uniform thermal expansion forces
2Productivity
If the catalyst granule size is reduced to improve reaction efficiency, then the surface area increases, but the thermal expansion stress concentration increases
Solution Approach 1:
The patent optimizes the catalyst granule size parameter to a specific range (0.5-2mm, preferably 0.8-1.5mm) that balances two opposing requirements: sufficient surface area for high reaction rate and appropriate size to distribute thermal expansion stress. This parameter optimization prevents both stress concentration from small particles and insufficient reaction efficiency from large particles
3Productivity
If the membrane reactor is used at high temperatures to improve reaction efficiency, then the reaction rate increases, but the thermal expansion difference between catalyst and membrane increases
Solution Approach 1:
The patent converts the harmful thermal expansion difference into a beneficial stress absorption mechanism. By allowing the catalyst granules to be in direct contact with the membrane and distributed throughout the cell, the thermal expansion of catalyst particles during high-temperature operation (150°C) is transformed into a cushioning effect that absorbs expansion stress, protecting the membrane from breakage while maintaining high reaction efficiency
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
This design effectively prevents breakage of the separation membrane by managing thermal expansion stress, maintaining permeance and reactor performance across temperature cycles.
Implementation Method 1
a catalyst that accelerates a chemical reaction of a starting material
Implementation Method 2
separating a high-permeability substance in the reactant from the starting material by causing the high-permeability substance to permeate the separation membrane
Implementation Method 3
stress may be caused by thermal expansion resulting from difference in thermal expansion coefficient or susceptibility to heating and cooling during temperature rise and drop
Data Source
AI summary
A membrane reactor includes a separation membrane complex and a catalyst. The separation membrane complex includes a separation membrane and a porous support. The catalyst accelerates a chemical reaction of a starting material. The support has a column-like shape extending in the longitudinal direction. The support has a membrane-formed cell (i.e., a first cell) having both longitudinal ends open. The first cell has an inner surface on which the separation membrane is arranged. The catalyst is arranged in the first cell of the separation membrane complex 1. The ratio of the average granule diameter of the catalyst to the inside diameter of the first cell is higher than or equal to 0.75 and lower than 1.