Petroleum sludge is currently one of the main residues of the refining process. Being an emulsion made up of hydrocarbons, water, heavy metals and solid particles, petroleum sludge is a critical issue for oil refineries, due to being a hazardous waste and, as a consequence, its very high handling and treatment costs. Among the wide range of technologies considered for the possible treatment of petroleum sludge for energy recovery, pyrolysis in a rotary kiln appears very promising, since the technology is sufficiently mature for other applications and requires only further optimization for the specific use.
The project aims to modify a rotary kiln pyrolysis plant configuration for energy recovery from petroleum sludge. The technology has been widely tested (in pilot and commercial units) for the treatment of different kinds of waste materials.
On the basis of the previous experience, a new pilot unit (capable of treating about 70-100 kg/h of petroleum sludge) will be designed, optimized for the specific application and installed at the Sotacarbo Research Centre, where high-level skills and infrastructure are already available. Several samples of petroleum sludge will be collected, characterized and tested in the new unit, with several key aims: (1) the optimization of the pyrolysis process with the specific fuel; (2) a kinetic analysis of the conversion process to identify the mechanisms of conversion and the phenomena related to heavy metals and other pollutants; (3) process optimization for the recovery of heavy metals.