Gioacchino Nardin

Waste-to-energy application in an industrial district

Industrial districts present some features that can be recognized and exploited in the plant engineering through the proposal of solutions which are not simple applications of models created for individual companies. This work illustrates a waste-to-energy plant to be used for the industrial waste of the district of Friuli Venezia Giulia. The project from the union between university and local entrepreneurs. It is described how the expense for woodworking-waste disposal can turn from a charge into an advantage for the firms of the district thanks to the incineration of this waste in a plant unique for the typology of waste treated. Each plant section is described in detail, underlining innovative approaches and solutions.

Application of high temperature phase change materials for improved efficiency in waste-to-energy plants

This study reports the thermal analysis of a novel thermal energy storage based on high temperature phase change material (PCM) used to improve efficiency in waste-to-energy plants. Current waste-to-energy plants efficiency is limited by the steam generation cycle which is carried out with boilers composed by water-walls (i.e. radiant evaporators), evaporators, economizers and superheaters. Although being well established, this technology is subjected to limitations related with high temperature corrosion and fluctuation in steam production due to the non-homogenous composition of solid waste; this leads to increased maintenance costs and limited plants availability and electrical efficiency. The proposed solution in this paper consists of replacing the typical refractory brick installed in the combustion chamber with a PCM-based refractory brick capable of storing a variable heat flux and to release it on demand as a steady heat flux. By means of this technology it is possible to mitigate steam production fluctuation, to increase temperature of superheated steam over current corrosion limits (450°C) without using coated superheaters and to increase the electrical efficiency beyond 34%. In the current paper a detailed thermo-mechanical analysis has been carried out in order to compare the performance of the PCM-based refractory brick against the traditional alumina refractory bricks. The PCM considered in this paper is aluminium (and its alloys) whereas its container consists of high density ceramics (such as Al2O3, AlN and Si3N4); the different coefficient of linear thermal expansion for the different materials requires a detailed thermo-mechanical analysis to be carried out to ascertain the feasibility of the proposed technology.

From Plastic Waste to Recycled-Content End Products: The Chair Industry Case

The paper describes a virtuous ecological cycle of recovering and recycling plastics from source separated collection that is realised in the chair industrial district in Friuli-Venezia Giulia. A process for converting the reclaimed plastic material into recycled-content end products has been running; in particular chairs with a 55% weight of recycled plastics are successfully manufactured by a local enterprise. This new product is able to close plastic waste management chain by recycling that type of recovered plastic without a defined market. Potential integration with local MSW system is proposed, in order to optimise waste management chain from both an environmental and economic point of view.