Heavy Oil Upgrading in a Hydrodynamic Cavitation Setup: The effect of Hydrogen Donor and Metal Nanoparticles

Cavitation technique can be used to increase the efficiency of the refining process of the heavy atmospheric and vaccum residuals and to upgrade the heavy stocks. The adiabatic collapse of the bubbles generated as a consequence of pressure reduction can produce conditions of very high localized temperature and pressure whilst the global conditions remain with no sensible change. In such a case, the bonds between atoms of molecules trapped in the bubble would be broken, some active radicals may be generated, chemical reactions may occur, and some catalyst particles may be activated. This paper investigated upgrading an Iranian refinery heavy fuel oil in a hydrodynamic cavitation setup. The system contains a feed tank, an internal 2 kW heating element, an additive container, a rotary pump (model DRP 16 lpm) with a 2.2 kW electric motor, a cavitation chamber, recycle pipe and a light products container. The stainless steel cavitation chamber consists of two narrow grooves at the top, a cone shape body and a collector at the bottom. Gasoline as a hydrogen donor and iron nanoparticles as catalyst were added to the cavitational heavy oil upgrading process. The results indicated that the cavitational processing in the presence of gasoline can reduce the viscosity and the total sulfur content of the heavy oil sample. Adding 1 vol% gasoline to a 10-minutes cavitational cracking process at 80 °C and atmospheric pressure can reduce the viscosity of heavy oil by 19%. In addition, iron nanoparticles increase the rate of hydrogen uptake and therefore the rate of viscosity reduction of heavy oil, in the presence of proper hydrogen donor.