Rotating Packed Bed Supercritical CO2 Desorption
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Solution Overview
Problem
The recovery of 2,2,3,3-tetrafluoro-1-propanol (TFP) from gas streams in DVD production is challenging due to its high volatility and environmental impact, and existing desorption methods are inefficient, especially in compact spaces like clean rooms, where conventional steam desorption is not feasible and requires large gas flow rates.
Innovation Solution
A method involving the use of a rotating packed bed with supercritical carbon dioxide as the desorbent, which enhances desorption efficiency through centrifugal force and pressure, allowing for effective recovery of TFP from activated carbon, even at ppm concentrations, by flowing supercritical CO2 through a rotating packed bed of spent adsorbent and expanding the effluent to collect the volatile component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional steam desorption technique is used, then desorption can be achieved, but equipment size is large and operational complexity increases
Solution Approach 1:
The patent changes the physical state parameter of CO2 from gaseous to supercritical by increasing pressure and temperature, enabling effective desorption without requiring large-scale steam generation equipment. This parameter change allows the use of a compact high-gravity contactor instead of conventional large-scale steam desorption systems.
Solution Approach 2:
The patent replaces the thermal steam-based desorption system with a supercritical fluid extraction system using CO2. This substitution eliminates the need for steam generation equipment, condensers, and associated complex mechanical systems, resulting in a more compact and operationally simpler device.
2Ease of operation
If conventional packed bed desorption is used, then desorption process is simple, but equipment size is large and not suitable for limited space
Solution Approach 1:
The patent introduces dynamic rotation to the packed bed system, creating a high-gravity environment that enhances mass transfer efficiency. The rotating packed bed (RPB) system dynamically adjusts the gravitational field strength, allowing for more efficient desorption in a compact volume compared to static conventional packed beds.
Solution Approach 2:
The patent changes the operational parameters by introducing high rotational speeds to generate centrifugal forces (20-100g). This parameter change dramatically increases the mass transfer rate and reduces the equipment volume required for effective desorption, making the system suitable for limited space applications.
3Productivity
If high gas flow rate is used for adsorption, then TFP recovery from ppm concentration is achieved, but equipment size and operational complexity increase
Solution Approach 1:
The patent changes the physical state of the desorbent to supercritical CO2, which has unique properties allowing for high-density mass transfer at lower flow rates. This parameter change enables effective TFP recovery from ppm concentrations without requiring the large gas flow rates needed in conventional systems, thus reducing equipment size and operational complexity.
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 method significantly improves desorption efficiency, reducing equipment size and operational complexity, achieving complete desorption within 30 minutes at higher rotating speeds and pressures, and allows for the reuse of activated carbon, making it superior to conventional packed bed desorption techniques.
Implementation Method 1
flowing a stream of supercritical carbon dioxide through a rotating packed bed of the spent adsorbent
Implementation Method 2
the centrifugal force replaces the gravitational force. Due to the presence of a centrifugal force, 20 to 100 gravities depending on rotating speed and radius of the rotating bed can be generated
Implementation Method 3
expanding the effluent at a reduced pressure to form a gaseous stream of carbon dioxide with the volatile component entrained therein
Implementation Method 4
adsorption onto porous adsorbents is believed to be the most appropriate technique. Among the adsorbents, activated carbon is the most commonly used due to its high surface area and low cost
Data Source
AI summary
A method of desorbing a volatile component from a spent adsorbent is disclosed, which includes flowing a stream of supercritical carbon dioxide through a rotating packed bed of the spent adsorbent; and collecting an effluent from the rotating packed bed, which contains supercritical carbon dioxide and the volatile component entrained therein. In one embodiment of the present invention a spent activated carbon from a process for recovering 2,2,3,3-tetrafluro-1-propanol from a gas stream containing 2,2,3,3-tetrafluro-1-propanol is regenerated by flowing a stream of supercritical carbon dioxide through a rotating packed bed of the spent activated carbon.