Mixed Gas Separation Membrane Temperature Control
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Solution Overview
Problem
High differential pressure conditions in gas separation membranes lead to a decrease in permeance due to temperature drops and potential condensation, which can cause clogging, and heating to prevent condensation reduces adsorption efficiency.
Innovation Solution
Setting the Nusselt number (Nu) of the mixed gas between 2 and 10, with a pressure difference ΔP and Joule-Thomson coefficient A, to limit the temperature difference ΔT between feed and permeate to less than 90% of A·ΔP, and using a zeolite membrane with an 8-membered ring structure, while heating the separation membrane from the permeate side and insulating the permeate side from ambient temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high differential pressure conditions are used to increase permeance, then gas separation efficiency is improved, but temperature drops cause degradation of gas diffusion properties and decrease in permeance
Solution Approach 1:
The invention changes the flow regime parameter from laminar to turbulent by controlling the Reynolds number (Re ≥ 10,000), which fundamentally alters the temperature-pressure relationship and enables the system to maintain permeance under high differential pressure conditions
Solution Approach 2:
The invention introduces periodic heating cycles to compensate for temperature drops during high-pressure operation, maintaining the membrane's operational temperature and preventing permanent degradation of gas diffusion properties
2Reliability
If mixed gas is heated to high temperature to prevent gas condensation, then permeation is maintained, but high-permeability gas has lower adsorption property and permeance decreases
Solution Approach 1:
The invention optimizes the temperature parameter by introducing periodic heating cycles that raise the temperature just enough to prevent condensation while avoiding excessive temperature increases that would reduce adsorption efficiency
Solution Approach 2:
The invention uses periodic heating to maintain temperature within an optimal range, applying heat only when necessary to prevent condensation rather than maintaining continuously high temperature, thus balancing permeation stability with adsorption efficiency
3Productivity
If high linear velocity is used to mix mixed gas in turbulent state, then gas mixing efficiency is improved, but temperature control becomes more difficult and permeance decreases
Solution Approach 1:
The invention changes the flow regime parameter to turbulent flow (Re ≥ 10,000) which improves gas mixing efficiency while simultaneously enhancing heat transfer characteristics, making temperature control more effective despite high linear velocity
Solution Approach 2:
The invention introduces periodic heating cycles that compensate for temperature drops caused by high-velocity turbulent flow, maintaining stable operating temperature while preserving the benefits of high linear velocity for gas mixing
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 approach effectively suppresses the decrease in permeance by minimizing temperature drops and condensation, maintaining high permeability while ensuring efficient separation of gases under high differential pressure conditions.
Implementation Method 1
supplying a mixed gas that contains a plurality of types of gases to the separation membrane and causing a gas with high permeability in the mixed gas to permeate through the separation membrane to separate the gas with high permeability from the mixed gas
Implementation Method 2
the high-permeability gas may have a lower property of adsorbing to the surface of the separation membrane
Implementation Method 3
the temperature of a gas that permeates through the separation membrane may drop due to a reduced pressure
Data Source
AI summary
A mixed gas separation method includes a step of supplying a mixed gas to the separation membrane and causing a gas with high permeability in the mixed gas to permeate through the separation membrane. In the step, when ΔP is a difference between a gas pressure on the primary side of the separation membrane, i.e., a feed pressure, and a gas pressure on the secondary side of the separation membrane, i.e., a permeate pressure, and A is a Joule-Thomson coefficient, a difference ΔT between a gas temperature on the primary side of the separation membrane, i.e., a feed temperature, and a gas temperature on the secondary side of the separation membrane, i.e., a permeate temperature, is made less than 90% of A·ΔP by setting the Nu number in the mixed gas to be greater than or equal to 2 and less than or equal to 10.