PROCESSES FOR THE MANUFACTURE OF ENRICHED PITCHES AND CARBON FIBERS

摘要

There are provided improved processes for the manufacture of enriched pitche s, carbon fiber precursors, carbon fibers, and graphite fibers. The improvement comprises employing an elevated wiped- film evaporator (105) in a wiped-film evaporator system comprising the wiped-film evaporator (105) and a means for recovering enriched pitch (119), such as a positive displace- ment pump (119), to form an enriched pitch from catalytic pitch and regulati ng the operating conditions of the wiped-film eva- porator system to provide the desired enriched pitch. The wiped-film evaporator (105) is located a specific distance above the means for recovering enriched pitch (119). The vertical distance between the outlet of the wiped-film evaporator (105) and the in- let of the means for recovering enriched pitch (119) is within the range of about 3 to about 15 meters, preferably about 6 to about 15 meters. Preferably the wiped-film evaporator (105) is heated with Dow Chemical Syltherm heat transfer media or its deriva- tives or equivalents.