System and method for densification of liquid oxygen

Abstract

A system and method for the production and supply of a densified, liquid oxidant to a space vehicle launch facility is provided. A stream of liquid oxygen taken from a co-located, liquid producing air separation unit is densified in a two refrigeration stage, integrated densification system. The first refrigeration stage is a nitrogen based reverse Brayton cycle refrigeration cycle that provides refrigeration to the second refrigeration stage. The second refrigeration stage is a helium and/or neon comprising refrigerant loop that densifies the liquid oxygen to a temperature between about 70 Kelvin and 57 Kelvin. The integrated densification system may also be configured to densify liquid methane or other propellants used in space vehicle launches.

1 . A system for production of a densified, liquid oxygen stream from a liquid oxygen stream, the system comprises:
 a first refrigeration stage configured to receive a first refrigerant and flow the first refrigerant through at least one first heat exchanger; and   a second refrigeration stage configured to flow a second refrigerant through a second heat exchanger configured to cool the second refrigerant via indirect heat exchange with one or more streams of the first refrigerant and configured to flow the second refrigerant through a densification heat exchanger to subcool and densify the liquid oxygen stream via indirect heat exchange with the second refrigerant;   wherein the first refrigeration stage further comprises:   a first warm refrigeration circuit, a second cold refrigeration circuit, a residual refrigeration circuit, and one or more recycle circuits;   wherein the first refrigerant flowing through the first heat exchanger is split into a first warm portion of the first refrigerant stream in the first warm refrigeration circuit, a second cold portion of the first refrigerant stream in the second cold refrigeration circuit, and a residual portion of the first refrigerant stream in the residual refrigeration circuit;   a warm turbine configured to expand the first warm portion the first refrigerant stream to yield an intermediate pressure warm exhaust;   a cold turbine configured to expand the second cold portion the first refrigerant stream to yield an intermediate pressure cold exhaust;   an expansion valve for expanding the residual portion of the first refrigerant stream to yield an expanded residual stream;   wherein the warm exhaust, the cold exhaust, and the expanded residual stream are recycled in the one or more recycle circuits to cool the first refrigerant stream; and   one or more first refrigerant recycle compressors configured to compress the recycled warm exhaust, the recycled cold exhaust, and the recycled expanded residual stream.   
     
     
         2 . The system for production of a densified, liquid oxygen stream of  claim 1  wherein the first refrigerant comprises nitrogen and the second refrigerant comprises helium or neon or both helium and neon. 
     
     
         3 . The system for production of a densified, liquid oxygen stream of  claim 2  wherein the second refrigeration stage is a closed loop refrigeration stage and further comprises:
 a second refrigerant recycle compressor disposed downstream of the second heat exchanger and configured to compress the second refrigerant; and 
 a second refrigerant turbine disposed upstream of the second heat exchanger and configured to expand the compressed second refrigerant. 
 
     
     
         4 . The system for production of a densified, liquid oxygen stream of  claim 1  wherein:
 the expanded residual stream is split into a first expanded residual stream and a second expanded residual stream; 
 the first expanded residual stream is further expanded and then recycled via the first heat exchanger as a low pressure return stream to cool the first refrigerant stream; and 
 the second expanded residual stream is one of the one or more streams of the first refrigerant flowing through the second heat exchanger to cool the second refrigerant. 
 
     
     
         5 . The system for production of a densified, liquid oxygen stream of  claim 4  wherein the warmed, low pressure return stream is compressed in the one or more of the first refrigerant recycle compressors. 
     
     
         6 . The system for production of a densified, liquid oxygen stream of  claim 4  wherein the warmed, second expanded residual stream is recycled to the one or more of the first refrigerant recycle compressors. 
     
     
         7 . The system for production of a densified, liquid oxygen stream of  claim 4  wherein the one or more streams of the first refrigerant flowing through the second heat exchanger further comprises a diverted portion of the cold exhaust. 
     
     
         8 . The system for production of a densified, liquid oxygen stream of  claim 7  wherein the warmed diverted portion of the cold exhaust is recycled to the one or more first refrigerant recycle compressors. 
     
     
         9 . The system for production of a densified, liquid oxygen stream of  claim 1  wherein the first refrigeration stage or the second refrigeration stage or both the first refrigeration stage and the second refrigeration stage are disposed on moveable platforms. 
     
     
         10 . The system for production of a densified, liquid oxygen stream of  claim 1  wherein the liquid oxygen stream is at a pressure between about 1.3 bar(a) and 3.0 bar(a). 
     
     
         11 . The system for production of a densified, liquid oxygen stream of  claim 1  wherein the one or more first refrigerant recycle compressors are configured to compress the recycled warm exhaust, the recycled cold exhaust, and the recycled first refrigerant return stream to a pressure greater than about 50 bar(a). 
     
     
         12 . The system for production of a densified, liquid oxygen stream of  claim 1  wherein the intermediate pressure warm exhaust and the intermediate pressure cold exhaust are at a pressure between about 5 bar(a) and 10 bar(a). 
     
     
         13 . The system for production of a densified, liquid oxygen stream of  claim 12  wherein the low pressure return stream is at a pressure below the pressure of the warm exhaust and the pressure of the cold exhaust. 
     
     
         14 . The system for production of a densified, liquid oxygen stream of  claim 1  further comprising a third refrigeration stage comprising a third heat exchanger configured to densify a stream of liquid methane via indirect heat exchange with a diverted portion of the expanded residual stream to yield a densified, liquid methane stream. 
     
     
         15 . A method of supplying a densified, liquid oxygen stream for a space vehicle launch, the method comprising the steps of:
 (i) producing a liquid oxygen stream and nitrogen refrigerants from an air separation unit;   (ii) cooling the nitrogen refrigerant in a first refrigeration stage comprising a first heat exchanger;   (iii) cooling a helium or neon containing second refrigerant in a second heat exchanger in a second refrigeration stage via indirect heat exchange with one or more streams of the nitrogen refrigerant;   (iv) subcooling and densifying the liquid oxygen stream in a densification heat exchanger in the second refrigeration stage via indirect heat exchange with the second refrigerant to yield a densified, liquid oxygen stream;   (v) transporting the densified, liquid oxygen stream to one or more launch platforms disposed at the launch facility;   
     
     
         16 . The method of  claim 15 , wherein the first refrigeration stage is a reverse Brayton cycle refrigeration stage and wherein step (ii) of the method further comprises the steps of:
 splitting the nitrogen refrigerant flowing through the first heat exchanger into a first warm portion of the nitrogen refrigerant stream, a second cold portion of the nitrogen refrigerant stream, and a residual portion of the nitrogen refrigerant stream;   expanding the first warm portion the nitrogen refrigerant stream in a warm turbine to yield an intermediate pressure warm exhaust;   expanding the second cold portion the nitrogen refrigerant stream in a cold turbine to yield an intermediate pressure cold exhaust;   expanding the residual portion of the nitrogen refrigerant stream to yield an expanded residual stream;   recycling the warm exhaust, the cold exhaust, and at least a portion of the expanded residual stream in one or more recycle circuits to cool the nitrogen refrigerant stream;   compressing the recycled warm exhaust, the recycled cold exhaust, and the recycled expanded residual stream in one or more nitrogen refrigerant recycle compressors.   
     
     
         17 . The method of  claim 16 , wherein the second refrigeration stage is a closed loop refrigeration stage and further comprises a second refrigerant recycle compressor disposed downstream of the second heat exchanger and configured to compress the second refrigerant; and a second refrigerant turbine disposed upstream of the second heat exchanger and configured to expand the compressed second refrigerant. 
     
     
         18 . The method of  claim 16 , further comprising the steps of:
 splitting the expanded residual stream into a first expanded residual stream and a second expanded residual stream;   further expanding the first expanded residual stream to yield a low pressure return stream;   recycling the low pressure return stream via the first heat exchanger to cool the nitrogen refrigerant stream;   wherein the second expanded residual stream is one of the one or more streams of the nitrogen refrigerant flowing through the second heat exchanger to cool the helium or neon containing second refrigerant.   
     
     
         19 . The method of  claim 18 , wherein the warmed, low pressure return stream is compressed in the one or more of the nitrogen refrigerant recycle compressors. 
     
     
         20 . The method of  claim 18 , wherein the warmed, second expanded residual stream is recycled to the one or more of the nitrogen refrigerant recycle compressors. 
     
     
         21 . The method of  claim 16 , further comprising the step of diverting a portion of the cold exhaust to through the second heat exchanger as one of the one or more streams of the nitrogen refrigerant flowing through the second heat exchanger. 
     
     
         22 . The method of  claim 21 , further comprising the step of recycling the warmed, diverted portion of the cold exhaust to the one or more of the nitrogen refrigerant recycle compressors.