Membrane Contactor Pressure Control for Acid Gas Wetting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Membrane contactors for acid gas removal are adversely affected by pore wetting, leading to increased mass transport resistance and degradation of performance, with existing solutions being application-specific and not providing a universal solution.
Innovation Solution
A membrane contactor system where the feed gas pressure is maintained above the liquid absorbent pressure, allowing a portion of the gas to bubble through the liquid absorbent, with precise control of gas and liquid phase pressures to minimize wetting, and a regenerative system to recycle and strip acid gases from the absorbent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If membrane contactor is used for acid gas removal, then large contacting area to volume ratio is achieved, but pore wetting occurs causing mass transport resistance increase
Solution Approach 1:
The patent changes the pressure parameter by maintaining gas phase pressure higher than liquid phase pressure, which reverses the traditional pressure differential approach. This parameter change prevents liquid from penetrating into membrane pores, thereby preventing pore wetting while maintaining the large contacting area advantage of membrane contactors.
2Reliability
If selective top layer is added to prevent wetting, then pore wetting is reduced, but resistance to mass transfer increases
Solution Approach 1:
Instead of modifying the membrane structure by adding a selective top layer, the patent changes the operating pressure parameters. By maintaining gas pressure higher than liquid pressure, the system prevents wetting through operational control rather than structural modification, thus avoiding the mass transfer resistance that would result from adding a dense protective layer.
3Reliability
If gas pressure is increased to prevent liquid penetration, then pore wetting is prevented, but gas bubbling through liquid increases
Solution Approach 1:
The patent converts the potentially harmful gas slippage (unabsorbed gas bubbling through liquid) into a beneficial recirculating flow. The gas that bubbles through the liquid is collected and recirculated back to the gas inlet, transforming what would be a loss into a useful process feature that maintains pressure differential and prevents wetting.
Solution Approach 2:
The system implements feedback by recirculating the gas that bubbles through the liquid back to the gas inlet. This feedback loop ensures continuous maintenance of the pressure differential across the membrane and optimizes the balance between preventing wetting and minimizing gas slippage losses.
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 prevents wetting, maintaining high efficiency over time by ensuring membrane fibers remain immersed in liquid and allowing controlled gas slippage, which improves overall process performance and extends membrane contactor lifespan.
Implementation Method 1
the liquid absorbent absorbs the at least one gas from the mixed gaseous feed stream
Implementation Method 2
The absorption is based on the chemical reaction between the selected amine and gas molecules
Implementation Method 3
a porous membrane which divides the absorption module into a gas-feed chamber and an absorbent chamber
Implementation Method 4
Desorbing said at least one gas from the rich liquid absorbent in the second membrane contactor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A membrane contactor for separating components from a feed gas stream comprises a housing, a feed gas inlet for receiving the feed gas stream at a first pressure, and a liquid inlet or receiving a stream of liquid at a second pressure, the liquid containing an absorbent for reacting components of the gas stream and a slip gas outlet. The contactor also includes a plurality of fibers with pore channels in contact with the feed gas incoming from the gas inlet on a first side, and in contact with liquid incoming from the liquid inlet on a second side, producing a gas-liquid interface at the pore channels. Liquid is prevented from wetting the pore channels by maintaining the first pressure of the gas stream higher than the liquid stream, and a portion of the gas stream bubbles through as slip gas into the liquid stream due to the elevated pressure.