The process pressure was also varied between a pressure of 750 psi at the lower packing temperature to a pressure of {HEAD ~ 450 psi} at {TAIL ~ the upper packing temperature} of 450° F.  
at
The process pressure was also varied between a pressure of 750 psi at the lower packing temperature to a pressure of { HEAD ~ 450 psi } at { TAIL ~ the upper packing temperature } of 450 ° F.
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH