Process optimization for the recovery of oil from tank bottom sludge using microwave pyrolysis

Petroleum refining generates hazardous sludge with polyaromatic hydrocarbons and heavy metals. The main objective of the study was to evaluate the performance of microwave pyrolysis for the recovery of oil from furnace oil sludge. The characteristics of furnace oil tank bottom sludge such as pH, moisture, viscosity, and volatile hydrocarbon content were determined. Thermal Gravimetric Analysis has been done to determine the cracking and degradation range of oily sludge. Gas Chromatography-Mass Spectrometry was used to fingerprint the hydrocarbon. Pyrolysis experiments were conducted in lab-scale pyrolysis setup with different susceptors and sludge in a specific weight ratio. The process parameters like microwave power, sludge: susceptor ratio were optimized to increase the oil yield. Graphite mixed sludge in 1:5 ratio at 450 W power shown higher oil yield. The calorific value of oil and char were determined as 44,442.9 and 16,686.58 kJ /kg. Physicochemical characteristics of oil such as flash point, density, and kinematic viscosity are 94 degrees C, 874.9, kg/m(3), and 4.063 cSt. Cetane index and sulfur content were measured as 40.9,6.85 g/kg respectively. The gas analysis had shown the presence of H-2, CO2, CO, and CH4 compounds. Char contains a higher percentage of carbon, Fe, Al, Ni, Pb, Cd, and S compounds. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

The objective of this study was to evaluate the performance of microwave pyrolysis for recovering oil from furnace oil sludge. Various process parameters were optimized to increase oil yield, and it was found that using a graphite mixed sludge in a 1:5 ratio at 450 W power showed higher oil yield. The study also determined the calorific value, physicochemical characteristics, and composition of the recovered oil and char.