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Il lavoro intende valutare le emissioni inquinanti causate da impianti civili, industriali e da traffico veicolare in un area urbana a contatto con il suo distretto industriale. Gli autori hanno utilizzato la metodologia CORINAIR (Cooridination Information AIR) per determinare i fattori di emissioni al fine di valutare l’entità delle emissioni in atmosfera. Il metodo è stato implementato alla città di Trieste e costituisce il primo passo per future ricerche sulla determinazione delle concentrazioni in atmosfera e al suolo degli inquinanti originati dalle diverse attività.

IMPIANTISTICA ITALIANA

Il lavoro illustra un sistema di supervisione, controllo e regolazione di un impianto per la distruzione dei rifiuti solidi urbani integrato con l’autoproduzione di energia elettrica. Dai calcoli si evince che l’investimento per la realizzazione del sistema rappresenta solo lo 0,5% del costo totale: un costo relativamente modesto, considerando gli enormi vantaggi che esso apporta per la gestione ottimale dell’impianto.

The study presented in this paper tests the empirical significance of several common recommendations for promoting better logging practices in tropicalforests: in particular, making concession agreements longer, linking renewal of those agreements to logging practices, and using performance bonds to encourage compliance with logging regulations. It assesses how these recommendations affect both the economics of timber harvesting and the provision of environmental benefits. With regard to the latter it focuses on carbon sequestration and biodiversity. It also examines the effects of timber fees and discount rates on economic and environmental outcomes. The study focuses on two aspects of logger behavior: choice of logging technology and compliance with prescribed minimum diameter cutting limits. The study analyzes loggers'decisions about technology and cutting limits in two scenarios: (i) the repeated harvesting of a given forest stand (virgin forest for the initial harvest, second growth forest for subsequent harvests), which occurs at a time delay of several decades (the cutting cycle); and (ii) the sequential harvesting of an annual series of different forest stands with identical characteristics (all virgin). The former gets at issues of sustainable forest management, while the latter gets at the mining of virgin timber stocks. In this way, the study examines both the long-run and short-run dynamics of logger behavior. The paper is organized as follows. The authors begin by describing the models of forest growth and logger behavior that comprise the simulation model. The description of the forest growth model includes the indicators used to predict the environmental impacts of logging, and the description of the model of logger behavior includes the regulatory instruments analyzed. Next, they present and discuss the simulation results, dealing with repeated harvesting and sequential harvesting in turn. In the final section the report highlights the principal conclusions that can be drawn from these results.

The purpose of this study is to simulate the distribution of a coarse granular material discharged in a hopper via a conveyor belt. This simulation is intended to be a model calibration for an optimization that will be later performed to obtain a proper material distribution device. From the hopper, the material is discharged in a blast furnace. Hence, achieving an adequate distribution in the hopper is crucial, since that distribution is directly linked to how the material spreads in the blast furnace, and this heavily influences the efficiency of the whole steel-making process. The apparatus is modeled by online three dimensional Computer-Aided Design software Onshape. Rocky DEM, a Computer-Aided Engineering software based on Discrete Element Method, is used to simulate the charge. The parameters of the numerical model are calibrated through an optimization algorithm. This phase is realized thanks to the optimization platform modeFRONTIER, using an algorithm that exploits meta-models to reduce the computational time of the optimization. By comparing the simulated results with the visual data obtained from blast furnace plant, the goal is to validate the model and to better understand the behavior of the whole charging process.

This paper is devoted to the evaluation of the use of low-GWP refrigerants in marine provision plants for cruise ships. We present the state of the art of current refrigeration plants, and we identify ammonia (NH3), carbon dioxide (CO2), and the HFOs R1234yf and R1234ze(E) as the most promising low-GWP refrigerants adequate for the marine refrigeration systems considered in the paper. Single-stage, two-stage and cascade plant configurations are examined, and the performances of the different alternatives are evaluated through simulations. The results are analyzed, and the performances are compared with those of the current systems with R407f: in the comparisons we consider COP, volumetric capacity, safety and environmental impact. We conclude that switching from current technologies to systems using low-GWP refrigerants entails a worsening of the performances in at least one of the areas considered. Moreover, we observe that the reduction of the GWP value of the refrigerants is not an effective strategy to diminish the total environmental impact of the refrigeration systems considered.

Thermal-hydraulic separators (or hydraulic dispatchers) are flow collectors of relatively small size, connecting two or more hydraulic networks; they are mainly used to reduce the hydraulic interference of primary (e.g. heat supply) and secondary (e.g. heat consumer) circuits, thereby simplifying the system analysis, saving energy and operating complex hydraulic networks more safely. Hydraulic dispatchers are key components of modern district heating networks and of building water systems: nonetheless, little is known about their internal flow and temperature distribution and about their off-design performance. The transfer of thermal energy from the primary to the secondary circuit is governed by the secondary-to-primary flow rate ratio and affected by the turbulent mixing within the device. A simple thermal model is commonly used for design purposes: it disregards the actual flow and temperature pattern within the device and relates the inflow and outflow temperature by neglecting the mixing of supply and return streams. This simple approach is potentially inaccurate under certain operating conditions (e.g. relatively high flow rates) and deserves a validation study. Numerical simulations of flow and heat transfer are carried out, for a family of geometrically similar thermal-hydraulic separators under different operating condition. The reported numerical tests show that the aforementioned model is a reliable design tool under most operation conditions. Furthermore, it is verified that the device introduces a relatively modest pressure loss on the connected circuits, in particular when the flow rate ratio is close to one.

The paper presents the results of a recent test campaign at an existing iron ore sintering plant in order to evaluate solutions to limit releases to air of dioxins. The solutions included primary containment measures (process integrated measures aimed at limiting the formation of pollutants) and secondary containment measures (end-of-pipe measures aimed at removing the pollutants produced), and the measurement campaign was planned to determine the operating conditions capable of complying with the legislation in force. The main aspects of the campaign are reported and the running conditions tested are defined. The results confirmed the need to integrate both types of containment measures in order to achieve the aims of the study.

The present paper is a result of a research project aimed at limiting the environmental impact of an Italian ironmaking plant. The present study is focused on the sinter plant in view of formulating effective structural, managerial and behavioural practices with regard to the identification and application of the best available techniques (BAT) in accordance with the Integrated Pollution Prevention and Control directive 96/61/EC. After a brief description of the plant under study, the most recent and most significant findings of the research with regard to the prevention of dioxin pollution with specific reference to the sinter plant are presented. The main objective is to verify the capability of technologies adopted at the plant to prevent the release to air of dioxins in compliance with limits placed by the local authority.

This paper, deriving from a joint effort of its authors, reports the results of a wide-ranging survey on particulate matter (PM) emissions from the operation of ironmaking plants, where this type of emissions is especially problematic and, if not properly addressed, may lead to environmental deterioration conditions that are totally incompatible with the protection standards set at the European Union level. With reference to the Lucchini Severstal plant in Servola (Trieste – Italy), the description of its operating cycle and the relevant flows of materials is followed by an estimation of PM emissions from each of its main activities. Technical and economic efforts were focused on the most critical ones. These efforts led to the implementation of plant retrofitting measures, presently completed, which are illustrated in the paper together with the environmental performances shown by the monitoring activity performed on its systems within the framework of the Integrated Environmental Authorisation required by the regional authority. The analysis of air quality in the areas surrounding the manufacturing plant performed through the monitoring of PM10 concentrations for a significant period of time, before and after the actions taken, shows a positive trend that confirms, on the one hand, the absolute relevance of this source of emissions and, on the other hand, the effectiveness of the aforementioned measures.

The paper presents the results of tests performed on an existing iron ore sintering plant to evaluate the limiting capability of dioxins releases to air and of measures and technologies adopted. These measures and technologies are in line with the best available techniques as stated in the Integrated Pollution Prevention and Control Directive 96/61/EC, so a measurement campaign was planned to determine the operating conditions capable of complying with the legislation in force. In this paper, the authors define the running conditions tested and the manner in which the testing campaign was performed. The results are presented and analysed in the light of the aims of the study.