Supercritical fluid chromatography system

Abstract

Provided is a chiller and system that may be utilized in a supercritical fluid chromatography method, wherein a non-polar solvent may replace a portion or all of a polar solvent for the purpose of separating or extracting desired sample molecules from a combined sample/solvent stream. The system may reduce the amount of polar solvent necessary for chromatographic separation and/or extraction of desired samples. The system may incorporate a supercritical fluid chiller, a supercritical fluid pressure-equalizing vessel and a supercritical fluid cyclonic separator. The supercritical fluid chiller allows for efficient and consistent pumping of liquid-phase gases employing off-the-shelf HPLC pumps. The pressure equalizing vessel allows the use of off the shelf HPLC column cartridges. The system may further incorporate the use of one or more disposable cartridges containing silica gel or other suitable medium. The system may also utilize an open loop cooling circuit using fluids with a positive Joule-Thompson coefficient.

What is claimed is: 
     
         1 . A chiller comprising:
 a) a first refrigerant circuit, comprising:
 i) a first compressor that pumps refrigerant through the first refrigerant circuit; 
 ii) 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; 
   b) a cryogenic refrigerant circuit in thermodynamic communication with the first refrigerant circuit, the cryogenic refrigerant circuit comprising:
 i) a second compressor that pumps cryogenic refrigerant through the cryogenic refrigerant circuit; 
 ii) the first tube-in-tube heat exchanger in fluid communication with the second compressor; wherein the cryogenic refrigerant flows through the inner lumen; 
 iii) a second tube-in-tube heat exchanger in fluid communication with the first tube-in-tube heat exchanger; wherein the second tube-in-tube heat exchanger comprises an inner lumen and an outer lumen that surrounds the inner lumen, wherein the cryogenic refrigerant flows through the outer lumen and wherein liquefied gas or supercritical gas flows through the inner lumen; 
   wherein the chiller does not comprise an intervening medium that mediates heat exchange between the first refrigerant circuit and the cryogenic refrigerant circuit and,   wherein the liquefied gas or supercritical gas exiting the inner lumen of the second tube-in tube heat exchanger is chilled.   
     
     
         2 . The chiller of  claim 1 , wherein the output liquefied gas or supercritical gas is chilled at least about 35° C. lower than the input liquefied gas or supercritical gas. 
     
     
         3 . The chiller of  claim 1 , wherein the refrigerant is selected from the group consisting of R-11, R-12, R-22, R-32, R-114, R-115, R-123, R-124, R-125, R-134A, R-142b, R-143a, R-152a, R-290, R-401A, R-401B, R-404A, R-407C, R-410A, R-409A, R-414B, R-416A, R-422B, R-422D, R-500, R-502, R-507, R-600 and mixtures thereof. 
     
     
         4 . The chiller of  claim 2 , wherein the refrigerant is selected from the group consisting of R-11, R-12, R-22, R-32, R-114, R-115, R-123, R-124, R-125, R-134A, R-142b, R-143a, R-152a, R-290, R-401A, R-401B, R-404A, R-407C, R-410A, R-409A, R-14, R-416A, R-422B, R-422D, R-500, R-502, R-507, R-600 and mixtures thereof. 
     
     
         5 . The chiller of  claim 1 , wherein the cryogenic refrigerant is selected from the group consisting of R-12, R-13, R-22, R-23, R-32, R-115, R-116, R-124, R-125, R-134A, R-142b, R-143a, R-152a, R-218, R-290, R-218, R-401A, R-401B, R-402A, R-402B, R-403B, R-404A, R-408A, R-409A, R-410A, R-4148, R-416A, R-422B, R-407A, R-407C, R-408A, R-409A, R-414B, R-422A, R-422B, R-422C, R-422D, R-500, R-502, R-503, R-508B, R-507, R-508B, R-600a and mixtures thereof. 
     
     
         6 . The chiller of  claim 2 , wherein the cryogenic refrigerant is selected from the group consisting of R-12, R-13, R-22, R-23, R-32, R-115, R-116, R-124, R-125, R-134A, R-142b, R-143a, R-152a, R-218, R-290, R-218, R-401A, R-401B, R-402A, R-402B, R-403B, R-404A, R-408A, R-409A, R-410A, R-4148, R-416A, R-422B, R-407A, R-407C, R-408A, R-409A, R-414B, R-422A, R-422B, R-422C, R-422D, R-500, R-502, R-503, R-508B, R-507, R-508B, R-600a and mixtures thereof. 
     
     
         7 . The chiller of  claim 3 , wherein the cryogenic refrigerant is selected from the group consisting of R-12, R-13, R-22, R-23, R-32, R-115, R-116, R-124, R-125, R-134A, R-142b, R-143a, R-152a, R-218, R-290, R-218, R-401A, R-401B, R-402A, R-402B, R-403B, R-404A, R-408A, R-409A, R-410A, R-4148, R-416A, R-422B, R-407A, R-407C, R-408A, R-409A, R-414B, R-422A, R-422B, R-422C, R-422D, R-500, R-502, R-503, R-508B, R-507, R-508B, R-600a and mixtures thereof. 
     
     
         8 . The chiller of  claim 1 , wherein the first refrigerant circuit further comprises in fluid communication with the first compressor and the first tube-in-tube heat exchanger:
 a first expansion valve; and   a liquid to air heat exchanger.   
     
     
         9 . The chiller of  claim 1 , wherein the cryogenic refrigerant circuit further comprises a second expansion valve in fluid communication with the second compressor, the first tube-in-tube heat exchanger and the second tube-in-tube heat exchanger. 
     
     
         10 . The chiller of  claim 1 , wherein first refrigerant circuit comprises a temperature sensor that measures a temperature and controls a rate of flow of refrigerant through the first refrigerant circuit. 
     
     
         11 . The chiller of  claim 1 , wherein the refrigerant is a fluid with a positive Joule-Thomson coefficient. 
     
     
         12 . The chiller of  claim 11 , wherein the first refrigerant circuit is an open loop cooling circuit, wherein the refrigerant is expelled from the circuit after passing through the first tube-in-tube heat exchanger. 
     
     
         13 . The chiller of  claim 11 , wherein the refrigerant is selected from the group consisting of hydrogen, nitrogen, argon, carbon dioxide. 
     
     
         14 . The chiller of  claim 11 , wherein the first refrigerant circuit comprises an expansion device to reduce the pressure of the refrigerant as it passes through the first tube-in-tube heat exchanger. 
     
     
         15 . The chiller of  claim 11 , wherein first refrigerant circuit comprises a temperature sensor that measures a temperature and controls a rate of flow of refrigerant through the first refrigerant circuit. 
     
     
         16 . The chiller of  claim 11 , wherein the refrigerant flows from the first compressor as source refrigerant through the first tube-in-tube heat exchanger before flowing to the second tube-in-tube heat exchanger as pre-cooled refrigerant, and wherein the refrigerant exits the second tube-in-tube heat exchanger as return refrigerant and flows through the first tube-in-tube heat exchanger as return refrigerant;
 wherein the refrigerant expands through an expansion device to become the cryogenic refrigerant that flows through the second tube-in-tube heat exchanger; and   wherein the source refrigerant is reduced in temperature in the first tube-in-tube heat exchanger by the return refrigerant.   
     
     
         17 . The chiller of  claim 16 , wherein the first refrigerant circuit is an open loop cooling circuit, wherein the return refrigerant is expelled from the circuit after passing through the inlet heat exchanger.