Dealkylation Mechanism Involved In Pyrolysis Of Heavy Oil In Supercritical Water And Structure Oriented Description Of Heavy Oil Composition

The feasibility of the carbonium mechanism based ?-scission during the pyrolysis of hydrocarbons in supercritical water(SCW)together with its resulting influence on dealkylation of aromatics was surveyed.The theoretical calculation indicates that a carbonium,no matter as a part of straight chain hydrocarbons or as the terminal of alkyl substitutes of aromatics,may decompose though ?-scission with similar reaction kinetic characteristics.By the pyrolysis of dodecene under SCW environments,it was found that in SCW the activation of a-olefins into carboniums is closely related to the ionic product of water.A higher water density favors the occurrence of the ?-scission in carbonium mechanism,by which a promoted conversion of dodecene and an increasing ratio of C3H6/C2H4 in the gaseous product can be observed.With the subsequent characterization on the asphaltenes resulted from the condensation of maltenes in SCW,the alternative approach of the dealkylation of aromatics in carbonium mechanism is further confirmed at increasing water densities.Then,the molecular composition of heavy oil has been simulated.After doing some modifications to original structure vectors,86 kinds of core seed molecules,totally 4321 kinds of molecular lumps were proposed to represent the molecular composition of heavy oil.Combining with optimizing algorithm and molecular lump database,the paper proposed a new method to calculate the molecular composition of heavy oil.The method reflected the composition and contents of molecular lumps of heavy oil.The calculation bulk properties of simulated heavy oil agreed with true values well.