US 11,781,809 B2
Mixed refrigerant system and method
Douglas A. Ducote, Jr., The Woodlands, TX (US); Timothy P. Gushanas, Pearland, TX (US); Peter J. Turner, The Woodlands, TX (US); and Michael Malsam, Sugar Land, TX (US)
Assigned to Chart Energy & Chemicals, Inc., Ball Ground, GA (US)
Filed by Chart Energy & Chemicals, Inc., Ball Ground, GA (US)
Filed on Aug. 4, 2022, as Appl. No. 17/881,117.
Application 17/881,117 is a division of application No. 16/545,695, filed on Aug. 20, 2019, granted, now 11,428,463.
Application 16/545,695 is a continuation in part of application No. 14/218,949, filed on Mar. 18, 2014, granted, now 10,480,851, issued on Nov. 19, 2019.
Claims priority of provisional application 61/802,350, filed on Mar. 15, 2013.
Prior Publication US 2022/0373255 A1, Nov. 24, 2022
Int. Cl. F25J 1/02 (2006.01); F25J 1/00 (2006.01)
CPC F25J 1/0244 (2013.01) [F25J 1/0055 (2013.01); F25J 1/0212 (2013.01); F25J 1/0262 (2013.01); F25J 2290/32 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A method for cooling a fluid with a mixed refrigerant including the steps of:
a. separating a high pressure mixed refrigerant stream to form a high pressure vapor stream and a high pressure liquid stream;
b. cooling the high pressure vapor in a heat exchanger, to form a mixed phase cold separator feed stream;
c. separating the mixed phase cold separator feed stream with a cold vapor separator, to form a cold separator vapor stream and a cold separator liquid stream;
d. condensing the cold separator vapor stream and flashing to form a cold temperature refrigerant stream;
e. cooling the cold separator liquid stream to form a subcooled cold separator liquid stream;
f. flashing the subcooled cold separator liquid stream using a cold separator liquid expansion device to form a first mixed phase stream;
g. cooling the high pressure liquid stream in the heat exchanger, to form a subcooled high pressure liquid stream;
h. flashing the subcooled high pressure liquid stream using a high pressure liquid expansion device to form a second mixed phase stream;
i. combining the first and second mixed phase streams to form a middle temperature refrigerant stream;
j. measuring a temperature of a fluid stream exiting the cold vapor separator;
k. comparing the temperature measured in step j. with a set point temperature;
l. Controlling a flow rate through the cold separator liquid expansion device or the high pressure liquid expansion device based on the comparison of step k;
m. determining a liquid level in the cold vapor separator and controlling the cold separator liquid expansion device based on the determined liquid level;
n. combining the middle temperature refrigerant stream and the cold temperature refrigerant stream;
o. warming the combined middle temperature refrigerant stream and cold temperature refrigerant stream in the heat exchanger to form a refrigerant return stream; and
p. thermally contacting a feed fluid in the heat exchanger, to form a cooled feed fluid product stream.