Systems and methods for improving the performance of dilution refrigeration systems are described. Filters and traps employed in the helium circuit of a dilution refrigerator may be modified to improve performance. Some traps may be designed to harness cryocondensation as opposed to cryoadsorption. A cryocondensation trap employs a cryocondensation surface having a high thermal conductivity and a high specific heat with a binding energy that preferably matches at least one contaminant but does not match helium. Multiple traps may be coupled in series in the helium circuit, with each trap designed to trap a specific contaminant or set of contaminants. Both cryocondensation and cryoadsorption may be exploited among multiple traps.

Systems and methods for improving the performance of dilution refrigeration systems are described. Filters and traps employed in the helium circuit of a dilution refrigerator may be modified to improve performance. Some traps may be designed to harness cryocondensation as opposed to cryoadsorption. A cryocondensation trap employs a cryocondensation surface having a high thermal conductivity and a high specific heat with a binding energy that preferably matches at least one contaminant but does not match helium. Multiple traps may be coupled in series in the helium circuit, with each trap designed to trap a specific contaminant or set of contaminants. Both cryocondensation and cryoadsorption may be exploited among multiple traps.

A method for cryogenic cooling without fouling is disclosed. The method comprises providing a first cryogenic liquid saturated with a dissolved gas; expanding the first cryogenic liquid into a separation vessel, separating into a vapor, a second cryogenic liquid, and a first solid; drawing the vapor into a heat exchanger and the second cryogenic liquid and the first solid out of the separation vessel; cooling the vapor against a coolant through the heat exchanger, causing the vapor to form a third cryogenic liquid and a second solid, the second solid dissolving in the third cryogenic liquid; and combining the second cryogenic liquid and the first solid with the third cryogenic liquid, producing a final cooled slurry. In this manner, the cryogenic cooling is accomplished without fouling.

A method for cryogenic cooling without fouling is disclosed. The method comprises providing a first cryogenic liquid saturated with a dissolved gas; expanding the first cryogenic liquid into a separation vessel, separating into a vapor, a second cryogenic liquid, and a first solid; drawing the vapor into a heat exchanger and the second cryogenic liquid and the first solid out of the separation vessel; cooling the vapor against a coolant through the heat exchanger, causing the vapor to form a third cryogenic liquid and a second solid, the second solid dissolving in the third cryogenic liquid; and combining the second cryogenic liquid and the first solid with the third cryogenic liquid, producing a final cooled slurry. In this manner, the cryogenic cooling is accomplished without fouling.

A cryopump includes a second cryopanel unit which is thermally connected to a second cooling stage of a cryocooler, a radiation shield which includes a shield main opening, a shield side opening, and a shield bottom opening, and a cryopump housing having a housing bottom portion which faces the shield bottom opening. A dimension of the shield bottom opening is larger than a distance from the second cryopanel unit to the housing bottom portion.

A cryopump includes a second cryopanel unit which is thermally connected to a second cooling stage of a cryocooler, a radiation shield which includes a shield main opening, a shield side opening, and a shield bottom opening, and a cryopump housing having a housing bottom portion which faces the shield bottom opening. A dimension of the shield bottom opening is larger than a distance from the second cryopanel unit to the housing bottom portion.

A multi-pass distillation system has a boiling flask with a side exit portal which is functionally connected to a condenser, which is, in turn, functionally connected to one or more cold traps. The condenser condenses wet vapors into liquid while the cold traps protect a pump which is used to suction the air through the system from the boiling flask through the condenser and cold traps. In this manner, one can more accurately collect fractions by way of a sideways exit from the boiling flask, near the top of the flask, with a condenser extending into a body of the spherical flask, such as at a 45 degree angle.

A multi-pass distillation system has a boiling flask with a side exit portal which is functionally connected to a condenser, which is, in turn, functionally connected to one or more cold traps. The condenser condenses wet vapors into liquid while the cold traps protect a pump which is used to suction the air through the system from the boiling flask through the condenser and cold traps. In this manner, one can more accurately collect fractions by way of a sideways exit from the boiling flask, near the top of the flask, with a condenser extending into a body of the spherical flask, such as at a 45 degree angle.

Disclosed is a process to produce a purified vapor comprising dialkyl-furan-2,5-dicarboxylate (DAFD). Furan-2,5-dicarboxylic acid (FDCA) and an alcohol in an esterification zone to generate a crude diester stream containing dialkyl furan dicarboxylate (DAFD), unreacted alcohol, 5-(alkoxycarbonyl)furan-2-carboxylic acid (ACFC), and alkyl furan-2-carboxylate (AFC). The esterification zone comprises at least one reactor that has been previously used in an DMT process.

Disclosed is a process to produce a purified vapor comprising dialkyl-furan-2,5-dicarboxylate (DAFD). Furan-2,5-dicarboxylic acid (FDCA) and an alcohol in an esterification zone to generate a crude diester stream containing dialkyl furan dicarboxylate (DAFD), unreacted alcohol, 5-(alkoxycarbonyl)furan-2-carboxylic acid (ACFC), and alkyl furan-2-carboxylate (AFC). The esterification zone comprises at least one reactor that has been previously used in an DMT process.