Heavy-Crude-Oil Upgrading With Transition Metals

Abstract

Abstract In this paper are discussed the effects of some metallic oxides used to upgrade the heavy crude oil properties. The underlying objective is to increase the mobility of the oil in the reservoir by reducing viscosity and improving the oil quality using alumina supported transition metals and liquid phase transition metals catalysts (derived from either acetylacetonate or alkylhexanoate compounds), both homogeneously mixed with heavy crude oil. This heavy crude oil upgrading is based on the decrement of the asphaltenes, resins, and sulfur contents, and the increment of its API gravity, and strong reduction of viscosity. In the present work the heavy crude oil from the Golf of Mexico was studied. The API gravity was increased from 12.5 to 21–26, the kinematics viscosity was decreased from 18,130 to 100–8 cSt (at 298 K), the asphaltene content was reduced from 26 to 7 wt%, the sulfur was removed in the range of 30 to 60 wt%, and the distillable fraction was increased between 20 to 30 wt%, and determinated by Simulated Distillation and True Boiling Point (TBP). Introduction Heavy crude oil can be an enormous energy source when the suitable technology is used to its improvement in both cases aboveground and within reservoir. The extremely large reserves of the heavy, extra-heavy crude oil and bitumenes (5.6 trillions barrels) and the low cost are the main factors that make attractive as feedstock in the refining industry [1, 2]. On the other hand, the word-wide of the conventional crude oil reserves have been drastically diminished to 1.02 trillions barrels causing in some countries (México) that a great percentage of heavy crude oil (50 vol.%) is mixed with conventional crude oil and is used as feedstock to the atmospheric distillation [1, 2]. Although in the past, the easy processing of the conventional crude oil favored the production of distillates, currently the situation is changing quickly and it could be different in a short term because of the high demand of fuels oil that is why it will be necessary to process heavy and extra heavy crude oil. Nowdays, some of the main problems that heavy crude oil presents are as follow:the low mobility through the reservoir as a consequence of its high viscosity, which affects the wells productivity index,the difficult transportation to the refineries and its high costs, andthe low processing capacity in the refineries. For these reasons is fundamental to enhance the heavy crude oil, both aboveground and underground. Talking about aboveground oil upgrading, several processes have been studied and applied in the industry to improve the bottom barrel conversion. Some of the main processes are carbon rejection (Thermal Processing, Delayed coking, Fluid coking, Flexicoking, and Visbreaking) [3–5]; hydrogen addition (Hydroprocessing, Fixed-bed as Hyvahl-F, Ebullating Bed as H-Oil and LC-Fining, and Slurry Phase) [6–9], and physical separation (Extractive Processes, FW Solvent Deasphalting, and Demex) [10–12]. All these processes are focused on converting the atmospheric and vacuum oil residues (511 K+) into more valuable products such as gasoline, middle distillates and Fluid Cracking Catalytic (FCC) feedstock. Nevertheless, the hydroconversion of heavy crude oil aboveground has been applied only at semi-industrial level because of:the special design of either fractionation towers or topping columns,the high investment due to great hydroprocessing volumes of heavy crude oil required in the refineries, and finallythe high hydrogen and catalysts consumption. An interesting alternative to recover the heavy and extra-heavy crude oil is the down-hole catalytic upgrading. This alternative presents several advantages comparing with its aboveground counterpart such as:an increase in the well productivity index,a reduction in the lifting and transportation costs from the downstream to the refining center,the production of more valuable products as a consequence of the decrement in viscosity values and in the resins, asphaltenes, sulfur, and metal contents, andthe application of environmentally accepted processes.