Oil sludge fuel mixtures with additives of fossil and biomass origin: Energy and operational parameters

Oil sludge combustion is a promising approach, suitable even for the recovery of heavy deposits. However, it comes with several technological limitations, in particular, high viscosity, unclear corrosion, ignition and combustion characteristics. The paper provides the analysis of the complex effects that can be obtained by mixing oil sludge with additives of plant and fossil origin (5-15 % share in a mixture). Methods included corrosion tests, thermal analysis, laboratory atomization and combustion, and multiple-criteria analysis. Diesel fuel and FAMEs reduced the viscosity of oil sludge by 3-12 times, so that the mixtures can be atomized. Methanol and process water did not sufficiently reduce oil sludge viscosity, and also worsened the corrosion characteristics upon contact with a steel, increasing the corrosion rate by 5-12 times. All additives intensified micro-explosive ignition and burnout of a fuel droplet. Experiments performed in a test furnace showed that the CO2/CO ratio increased by 2.5-2.6 times, which confirmed the advantageous synergistic effect of droplets when atomizing fuel. From an environmental and energy point of view, FAMEs from distilled tall and waste cooking oils are the most promising. The greatest technological effect will be provided by mixing oil sludge and Diesel fuel.