Microwave application in petroleum processing

Abstract

Electromagnetic aspects of energy transfer between microwaves and other forms of matter are comprehended in processes where microwave energy is used to affect a chemical or physical change.Though its implications in petroleum applications are yet to be fully understood, the non-thermal aspects of energy transfer between microwaves and other forms of matter are always visible in processes where microwave energy is used to cause a chemical or physical change in the irradiated material. The depletion of conventional crude oil reserves is accompanied by growing economic demand for various types of fuel, biodiesels and petrochemical products creating the need for remediation of heavier asphaltenic crude [1]. Thus, the extraction, transportation and refining of this highly viscous, high paraffinic, high sulfur content crude oil and its wastes is becoming more prominent since heavy oil deposits exceed light oil deposits by two orders of magnitude [2]. In this work, multiple crude oils were studied for hydro-desulphurization (HDS) and defragmentation processes by a novel method of microwave irradiation. The specific objectives were to identify conditions that would upgrade the oil and simultaneously substantially reduced the sulphur content using microwave irradiation, and to obtain preliminary data on process economics. Results showed strong indications for the microwave technology to be employed not only for hydrocarbon extractions but also for in-situ and field upgrading of heavy oil, and reduction in sulphur content of crude oil. There was evidence of fragmentation and combination reactions present in the process, as well as high percentreduction in sulphur content. Overall, the microwave technologypresents the best alternative, economically and environmentally, to the existing technologies for enhanced oil recovery operations and processing. The microwave process employs specific frequency microwaves targeted into the formation containing heavy hydrocarbons to initiate conversion of the hydrocarbon into synthetic crude, with reduced discharge of greenhouse gas into the environment as natural gasor other fuels are not required to reduce viscosity [3]. The specific objectives were to identify conditions that would upgrade the oil and achieve up to 50% desulphurization using microwave irradiation, and to obtain preliminary data on process design and economics. Typical reactions in the removal of various organic sulphur compounds have been identified as follows: Thiols R—SH + H2 → RH + H2 S Naphthenes-, Aromatic-, and Alkyl- Suphides R—S—R’ + 2H2 → RH + R’H + H2 S Disulphides R—SS—R’ + 3H2 → RH + R’H + 2H2 S The process of the study was based upon expansion of Miadonyeet al.’s 2009 article focusing upon crude oil desulphurization, howeverin the case of this project, acquiring a further array of oil compositions and loosely defining the limits of microwave exposure.