LABORATORY STUDY OF REAL-TIME OPTICAL MICROSCOPE TRACKING OF THERMAL-REACTION PROGRESS OF VACUUM RESIDUA .1. PHYSICAL PROCESSES IN THERMAL-REACTION SYSTEMS OF VACUUM RESIDUA

Under the thermal autoclave conditions of 370 similar to 390 degrees C and 1.0MPa N-2(initial pressure in the autoclave gaseous compartment) , and with the residence time extending, there occur in succession thr ee different characteristic states detectable and distinguishable by t he optical microscope in the respective thermal reaction systems of Da qing, Shengli and Gudao vacuum residua. Results from the freeze-fractu re replication transmission electronic microscopy and the spot test of the studied thermal reaction systems have indicated that the first ch aracteristic state, at which the neo-phases have the minimum bulk effe cts on the system, arises from the aggregation and phase separation of the proto-asphaltenes due to the loss of the kinetic stability of the vacuum residuum colloids. At the third characteristic state, the reac tion system enters a critical flocculation state and the neo-phases oc curring at its onset point have the maximum bulk effects on the system . The practical implication of the second characteristic state is not obvious enough.