Reactor Design of Microwave Assisted Demetallization of Heavy Crude Oil

Abstract

In the recent years with the deeper exploiting of world-wide crude oil, the heavy and poor trend of which is aggravating, inducing the metal contents in the oil increasing rapidly. Vanadium (V) and nickel (Ni) are the most harmful metals to petroleum processing among these metals, which mainly displays poisonous effect to the catalysts of Fluid Catalytic Cracking (FCC) and hydrogenation. The commonly used technologies to remove these metals can be classified into physical method, chemical method and catalytic hydroprocessing method. Hydrodemetallization (HDM) is widely employed in industry. However, the products of HDM reactions can accumulate in the catalyst pores, causing the formation of deposits which end up obstructing those pores irreversibly, blocking access to the catalyst sites and leading to a progressive loss of catalytic activity. Thus the removal of nickel and vanadium from crude oil has become a challenge in petrochemical processing. This work focuses on these metals removal by using microwave heating technology. A suitable reactor was first developed through numerical simulation technology using COMSOL. It was found that the reactor with a radius of 20 mm shows good coupling with microwaves, and the optimized loading height achieved is 40 mm. Experiments of demetallization were then conducted for Venezuela crude oil using this reactor, the maximum removal rate of 72.4 % and 76.8 % were obtained for Ni and V respectively. However, by using this batch reactor, the temperature distribution is non-uniform within the treated material, a continuous system were therefore developed to overcome the un-even electric field distribution. The reactor was designed as a cylinder with the length of 500 mm, and different crude oil flow rates were simulated, good demetallization rate can be achieved using the same microwave operating conditions.