The method 6 wherein the step of injecting {HEAD ~ a flow} of cold cryogen vapor includes the steps of injecting at least a first flow of {TAIL ~ cold cryogen vapor} into the first conduit means, and injecting at least a second flow of cold cryogen vapor into the second conduit means 
The method 6 wherein the step of injecting { HEAD ~ a flow } of cold cryogen vapor includes the steps of injecting at least a first flow of { TAIL ~ cold cryogen vapor } into the first conduit means , and injecting at least a second flow of cold cryogen vapor into the second conduit means
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH