A pilot scale throated downdraft gasifier was operated with vine prunings as feedstock to assess ... more A pilot scale throated downdraft gasifier was operated with vine prunings as feedstock to assess the effect of biomass loading rate on process performance. A distributed 1D model of mass and heat transfer and reactions was applied to aid the interpretation of experimental evidence. The model takes into account peculiar gasifier design features (air inlets and throat) and it reproduces satisfactorily the temperature profiles and the mass fluxes of gaseous species at different biomass loading rates. The integration of pilot-scale experiments and numerical simulations provides sound indications for the gasifier operation. In particular, simulations performed at different loading rates and feedstock humidity show that steady state operation and stable performance of the gasifier rely on the thermal balance between the enthalpy of cold biomass moving downward and the counter-current radiative heat fluxes moving upward from the oxidation zone. This balance can be destabilized by high load...
A Computational Fluid Dynamics model of a pilot-scale entrained flow reactor is developed with th... more A Computational Fluid Dynamics model of a pilot-scale entrained flow reactor is developed with the aim to shed light into the cloud of solid fuel particles. An iterative procedure is suggested to derive devolatilization kinetics: particle average residence times and heating rates are estimated from the numerical model, and a linear dependence of the particle temperature with residence time is assumed. In this manner the volatile release equation can be integrated analytically and subsequently kinetic parameters can be obtained from experimental conversion data. The procedure is shown for a Sebuku type coal in oxy-fuel conditions. Introduction The development of clean and efficient technologies for power generation from solid fuels such as biomass and coal, would benefit of detailed simulations tools as Computational Fluid Dynamics, able to handle a turbulent reactive multiphase flow in a complex geometry without any need of scale-up procedures. Despite the huge increase in computati...
Biodiesel production facilities are widespread in the world as the demand for “green” fuels incre... more Biodiesel production facilities are widespread in the world as the demand for “green” fuels increase continuously. So, the number of accidents increases with the number and the capacity of plants. In this paper, the fire and explosion risks in biodiesel production facilities are discussed. Beside some evident risk sources such as flammable storage tanks, we have shown that process deviations may give a relevant contribution to the overall risk and that two critical aspects may be: the excess of the amount of residual methanol in the streams fed to the phase separation step (e.g. biodiesel/unreacted separation after reaction, or glycerin/fatty acids separation), which can affect separation efficiency, and the condensation of flammable vapour streams.
... There is still a need to understand better the temper 00102180 95 9.50 SSDI 00102180(95) 0008... more ... There is still a need to understand better the temper 00102180 95 9.50 SSDI 00102180(95) 00089O 182 V. COZZANI ET AL. ... 1. Electrodynamic thermogravimetric analyzer (EDTGA). 184 V. COZZANI ET AL. An optical microscope and a video camera allow particle viewing. ...
The use of biopolyesters, as polymeric matrices, and natural fillers derived from wastes or by-pr... more The use of biopolyesters, as polymeric matrices, and natural fillers derived from wastes or by-products of food production to achieve biocomposites is nowadays a reality. The present paper aims to valorize mussel shells, 95% made of calcium carbonate (CaCO3), converting them into high-value added products. The objective of this work was to verify if CaCO3, obtained from Mediterranean Sea mussel shells, can be used as filler for a compostable matrix made of Polylactic acid (PLA) and Poly(butylene adipate-co-terephthalate) (PBAT). Thermal, mechanical, morphological and physical properties of these biocomposites were evaluated, and the micromechanical mechanism controlling stiffness and strength was investigated by analytical predictive models. The performances of these biocomposites were comparable with those of biocomposites produced with standard calcium carbonate. Thus, the present study has proved that the utilization of a waste, such as mussel shell, can become a resource for bio...
A pilot scale throated downdraft gasifier was operated with vine prunings as feedstock to assess ... more A pilot scale throated downdraft gasifier was operated with vine prunings as feedstock to assess the effect of biomass loading rate on process performance. A distributed 1D model of mass and heat transfer and reactions was applied to aid the interpretation of experimental evidence. The model takes into account peculiar gasifier design features (air inlets and throat) and it reproduces satisfactorily the temperature profiles and the mass fluxes of gaseous species at different biomass loading rates. The integration of pilot-scale experiments and numerical simulations provides sound indications for the gasifier operation. In particular, simulations performed at different loading rates and feedstock humidity show that steady state operation and stable performance of the gasifier rely on the thermal balance between the enthalpy of cold biomass moving downward and the counter-current radiative heat fluxes moving upward from the oxidation zone. This balance can be destabilized by high load...
A Computational Fluid Dynamics model of a pilot-scale entrained flow reactor is developed with th... more A Computational Fluid Dynamics model of a pilot-scale entrained flow reactor is developed with the aim to shed light into the cloud of solid fuel particles. An iterative procedure is suggested to derive devolatilization kinetics: particle average residence times and heating rates are estimated from the numerical model, and a linear dependence of the particle temperature with residence time is assumed. In this manner the volatile release equation can be integrated analytically and subsequently kinetic parameters can be obtained from experimental conversion data. The procedure is shown for a Sebuku type coal in oxy-fuel conditions. Introduction The development of clean and efficient technologies for power generation from solid fuels such as biomass and coal, would benefit of detailed simulations tools as Computational Fluid Dynamics, able to handle a turbulent reactive multiphase flow in a complex geometry without any need of scale-up procedures. Despite the huge increase in computati...
Biodiesel production facilities are widespread in the world as the demand for “green” fuels incre... more Biodiesel production facilities are widespread in the world as the demand for “green” fuels increase continuously. So, the number of accidents increases with the number and the capacity of plants. In this paper, the fire and explosion risks in biodiesel production facilities are discussed. Beside some evident risk sources such as flammable storage tanks, we have shown that process deviations may give a relevant contribution to the overall risk and that two critical aspects may be: the excess of the amount of residual methanol in the streams fed to the phase separation step (e.g. biodiesel/unreacted separation after reaction, or glycerin/fatty acids separation), which can affect separation efficiency, and the condensation of flammable vapour streams.
... There is still a need to understand better the temper 00102180 95 9.50 SSDI 00102180(95) 0008... more ... There is still a need to understand better the temper 00102180 95 9.50 SSDI 00102180(95) 00089O 182 V. COZZANI ET AL. ... 1. Electrodynamic thermogravimetric analyzer (EDTGA). 184 V. COZZANI ET AL. An optical microscope and a video camera allow particle viewing. ...
The use of biopolyesters, as polymeric matrices, and natural fillers derived from wastes or by-pr... more The use of biopolyesters, as polymeric matrices, and natural fillers derived from wastes or by-products of food production to achieve biocomposites is nowadays a reality. The present paper aims to valorize mussel shells, 95% made of calcium carbonate (CaCO3), converting them into high-value added products. The objective of this work was to verify if CaCO3, obtained from Mediterranean Sea mussel shells, can be used as filler for a compostable matrix made of Polylactic acid (PLA) and Poly(butylene adipate-co-terephthalate) (PBAT). Thermal, mechanical, morphological and physical properties of these biocomposites were evaluated, and the micromechanical mechanism controlling stiffness and strength was investigated by analytical predictive models. The performances of these biocomposites were comparable with those of biocomposites produced with standard calcium carbonate. Thus, the present study has proved that the utilization of a waste, such as mussel shell, can become a resource for bio...
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Papers by Leonardo Tognotti