Feasibility study of the preparation of RFO from deasphalted pitch

Abstract

Crude oil is fractionated into different products as it is composed of thousands of different compounds having different boiling points. Crude oil is generally described as sweet, sour, light, and heavy crude. This nature of crude decides its processing in the refinery. In a typical petroleum refinery, the refinery design is based on the crude potential and the targeted product. The upgradation of petroleum pitch is a versatile challenge since ever. There are several approaches used to upgrade petroleum pitches. Several known methods are solvent deasphalting, visbreaking, delayed coking, and bitumen making. Solvent deasphalting is important as it is used to make lubricating oil of different grades and wax. The primary purpose of SDA is to decrease the metal content and waxes (paraffin) in the deasphalted asphalt. This approach overall increases the insoluble metals and reduces the oil in asphalt, and thus, up-gradation of asphalt becomes difficult further. This paper describes the upgradation of deasphalted pitch to make fuel oil of different viscosity grades using Kero, light vacuum gas oil, and light cycle oil as cutter stocks. In this study, it had been tried to make fuel oil as per IS 1593: 2018. The detailed study showed that when the deasphalted pitch is blended with cutter stocks, it resulted in fuel oil of different grades. The study also showed the effect of addition kero on the calorific value. This study clearly defines why Kero was not suitable for the formation of fuel from deasphalted pitch based on high-resolution mass spectroscopy (HRMS). HRMS analysis showed that kero fraction contains maximum saturates 75.1 % while light cycle oil contains maximum aromatics 59.8 %. Finally, the study showed that why light cycle oil is found suitable for the preparation of fuel from deasphalted aromatics pitch. ASTM D 6730 also confirms the non-suitability of kero fraction to prepare fuel oil and support the HRMS data.