Supercritical fluid chromatography system
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Solution Overview
Problem
Traditional flash chromatography systems face inefficiencies due to high organic solvent usage and inconsistent mass flow rates in supercritical carbon dioxide extraction systems, particularly with cavitation effects in pump systems, leading to non-repeatable and non-proportional mass flow rates.
Innovation Solution
A supercritical fluid chromatography system incorporating a chiller with dual refrigeration circuits and a pressure equalizing vessel, along with a cyclonic separator, to efficiently manage supercritical fluids, reduce organic solvent use, and achieve consistent mass flow rates by subcooling liquefied gases and utilizing standard HPLC pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a piston-style positive displacement pump is used to supply high pressure carbon dioxide, then high pressure (>100 bar) can be achieved, but mass flow rates are not proportionate to pump speed due to cavitation effects
Solution Approach 1:
The system pre-cools the carbon dioxide before it enters the pump using a heat exchanger connected to a refrigeration system. This preliminary cooling action ensures the CO2 is in a liquid state with appropriate viscosity, preventing cavitation in the pump and ensuring proportional mass flow rates while maintaining high pressure capability
Solution Approach 2:
The system changes the temperature parameter of the carbon dioxide by using a refrigeration system to cool it to a specific range (−10°C to 0°C). This parameter change transforms the CO2 into a liquid state that is suitable for positive displacement pumping, eliminating cavitation issues and ensuring consistent mass flow rates proportional to pump speed
2Productivity
If traditional flash chromatography is used, then separation can be performed, but large amounts of organic solvents (80-90% of flow stream) are consumed
Solution Approach 1:
The system uses supercritical carbon dioxide as the mobile phase instead of traditional organic solvents. By adjusting temperature and pressure parameters to achieve supercritical state, the system maintains effective separation capability while eliminating the need for large amounts of organic solvents, reducing solvent consumption from 80-90% to minimal amounts
Solution Approach 2:
The system replaces organic solvents with carbon dioxide in its supercritical state, creating an inert environment that provides effective chromatographic separation. This substitution eliminates the use of harmful organic solvents while maintaining separation performance, addressing both productivity and environmental concerns
3Temperature
If inlet CO2 temperature is reduced to 2°C to 5°C using waterless refrigeration, then the temperature is within single stage compressor range, but pump performance is not repeatable and linearization via compensation fails
Solution Approach 1:
The system changes the temperature parameter from 2-5°C to a lower range of -10°C to 0°C, and more importantly, maintains this temperature consistently through proper refrigeration control. This parameter optimization ensures the CO2 remains in the appropriate liquid state for pumping while achieving repeatable and proportional mass flow rates
Solution Approach 2:
The system incorporates temperature control through a refrigeration system with heat exchangers that continuously monitor and adjust the CO2 temperature before it enters the pump. This feedback control ensures consistent thermal conditions, eliminating the variability that caused non-repeatable pump performance
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 system significantly reduces organic solvent usage, achieves consistent and repeatable mass flow rates proportional to pump speed, and enables the use of standard HPLC pumps in supercritical fluid applications, enhancing the efficiency and cost-effectiveness of chromatography processes.
Implementation Method 1
subcooling the liquid-phase gas to a temperature of −10° C. or lower
Implementation Method 2
a first tube-in-tube heat exchanger in fluid communication with the first compressor, wherein the first tube-in-tube heat exchanger comprises an inner lumen and an outer lumen that surrounds the inner lumen, wherein the refrigerant flows through the outer lumen
Implementation Method 3
a cyclonic separator comprising: a cyclone body comprising an inner surface, an outer circumference, a top outlet, a tangential inlet and a bottom outlet
Implementation Method 4
a first compressor that pumps refrigerant through the first refrigerant circuit
Data Source
AI summary
Provided is a supercritical fluid chromatography system, and components comprising such a system, including one or more of a supercritical fluid chiller, a supercritical fluid pressure-equalizing vessel, and a supercritical fluid cyclonic separator. The supercritical fluid chiller and the use of the chiller allow efficient and consistent pumping of liquid-phase gases employing off-the-shelf HPLC pumps in the supercritical chromatography system using liquid-phase gas mobile phase. The pressure equalizing vessel allows the use of off the shelf HPLC column cartridges in the supercritical chromatography system. The cyclonic separator efficiently and effectively allows for separation of sample molecules from a liquid phase or gas phase stream of a supercritical fluid.