Fausto Pochetti

Gasification process of wastes containing PVC

Abstract Solid waste, in dealing with the growing presence of organic compounds, especially plastics, can be considered an important source of energy since they are inexpensive and easily obtainable materials. However, the presence of polyvinyl chloride (PVC) in the waste can result in a recycling problem when thermal treatment is involved. This work shows the possibilities of recovering energy from waste containing PVC by a gasification process without additional dechlorination facilities. Experimental data obtained in a bench scale two-stage reactor indicate that the addition of Na2CO3 in a blend containing refuse-derived fuel (RDF) and PVC is efficient in eliminating chlorine from the produced off-gas. On the contrary, the less expensive calcium compounds do not show a satisfactory chlorine removal. A thermodynamic simulation of the process substantially leads to the same results. Starting from this study, the working conditions for gasifying waste blends containing PVC in a scaled-up two-stage reactor can be predicted. According to the simulation, the obtained syngas shows that the polluting compounds content is lower than the Italian law limit. As a consequence, it can be used directly to obtain electric power and/or local heating.

Removal of PCBs from mineral oils

Abstract The paper deals with the elimination of PCBs from dielectric and contaminated lube oils by using the KPEG process. Experimental runs at lab scale showed that the treatment is effective on both kinds of oils, but the degree of PCBs removal is higher in case of dielectric oils. The PCB elimination grade is affected by both KOH/PEG and PEG/oil ratios, and strongly by the nature of the PCB mixture. In fact, the reactivity of less chlorinated PCBs, i.e. with 3–5 chlorine atoms, is two orders of magnitude lower than that of PCBs with 5–7 chlorine atoms.

Automobile shredder residue gasification

Automobile Shredder Residue (ASR) shows a broad chemical composition owing to the presence of different materials, and its high organic content makes it interesting as a source of energy. In this work, a bench scale two-stage reactor is used for gasifying ASR. The reactor shows an efficient ASR gasification, avoiding the formation of difficult to manage char and tar and allowing an easy recovery of energy. The results of the investigation were used to test a simple model based on mass and energy balances and chemical equilibrium, predicting syngas composition including the presence of problematic elements such as sulphur and chlorine. Gasification data calculated by the model agree in a satisfactory way with the experimental ones. Due to the large variation in ASR composition, the model predicts that ASR gasification is industrially feasible only if a blend of ASR and RDF is used as a reactor feed.

Pyrolysis of automotive shredder residues: a lumped kinetic characterization

A lumped kinetic model for the pyrolysis of industrial wastes of unknown chemical composition is developed. The model is applied to the pyrolysis of automotive shredder residues (ASRs), studied by means of thermogravimetric and calorimetric analyses, in isothermal and non-isothermal conditions.

DECHLORINATION OF POLYCHLORINATED BIPHENYLS IN NON-POLAR MEDIA

Abstract The paper deals with the application of the KPEG technology to the treatment of both dielectric and lube used oils is reported. The experimental results, achieved by using the two class of oils, are compared in order to evaluate the reduced efficiency of the process when lube oils are treated . The kinetic of the PCBs removal reaction from a mineral oil was determined; the reaction resulted first order relatively to each congener concentration and first order relatively to the polyethylene glycol alkoxide concentration. The calculated kinetic constants for the considered congeners, have showed an exponential correlation with their gas-chromatographic relative retention time . From the kinetic results it is confirmed that the slightly chlorinated PCB are more hardly removed, whereas the more chlorinated PCBs are those more easily eliminated.; the kinetics of PCBs removal seems to be strongly affected by their structural conformation and not only by the chlorine content .