Pyrolysis Of Heavy Oil In Supercritical Water

In recent years, lots of achievements have been made in the heavy oil upgrading research under traditional conditions. However, lacking of available basic data for design and estimation, pyrolysis of heavy oil in supercritical water, one of unconventional treatments for upgrading of heavy oil, is still not industrialized.Therefore, it is very important to understand the principle of pyrolysis of heavy oil to establish the basic theory of upgrading in the supercritical water.The product distribution of pyrolysis of heavy oil in the presence of high pressure nitrogen and supercritical water was investigated. Sequentially, the products were divided into six components to build the complex network. The study shows that reaction in supercritical water is faster than that in high nitrogen pressure. Pyrolysis of heavy oil can be transferred into water phase in SCW, as a result, hydrocarbon environment changes and mass transfer is enhanced to promote the condensation of maltene. Simultaneously, the aspaltene molecules derived from condensation of maltene in the SCW possesses coke-like structure, which increases the rate of coke formation. In addition, the resin and aromatic can be transformed to each other, and both of them can be cracked into saturates, which can only be cracked into gas.Through literature and our previous experiments, reaction network for heavy oil cracking is built, and the six-lump model for the pyrolysis of heavy oil in the presence of SCW and high nitrogen pressure is established by lumping theory;Its model parameters are determined by regression analysis. Based on these work, tendency of the product distribution of heavy oil pyrolysis is predicted and optimal upgrading conditions has been obtained by the six-lump model.