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Abstract This paper presents a non-stoichiometric equilibrium model for the simulation of biomass downdraft gasifiers. The chemical equilibrium is determined by minimizing the Gibbs free energy. Five elements characterize the biomass and 15 chemical species are considered in the syngas. The model calculates the lower heating value of the syngas and the relative abundances of gasification products. An advantage of this model is that it can easily calculate not only the concentrations of the main gasification products, but also the concentrations of minor product, especially the pollutant chemical species containing Nitrogen and Sulfur. To analyse the model behaviour, a sensitivity analysis on process parameters is presented. The model is validated by comparing its results with the results of simulation carried out with a stoichiometric model and with experimental data found in literature. Finally, the model is applied to the study of the gasification of forest waste.

AbstractA metal-organic framework, UiO-66, has been evaluated as adsorbent in a post-combustion vacuum swing adsorption (VSA) process. Equilibrium isotherms of the most relevant gases (CO2 and N2) as well as breakthrough curves measured using synthetic flue gas containing 15 mol% CO2 without and with 9 mol% water vapor are reported. Based on the breakthrough data, a six step one-column VSA cycle is designed and the effects of adsorption and CO2 rinse times used on the CO2 recovery and CO2 purity are examined. With the chosen process configuration and cycle design CO2 purities around 60% and CO2 recoveries up to 70% are achieved. 50 cycle adsorption-desorption experiments show that the cyclic CO2 capacity is reduced by approximately 25% in the presence of water vapor. No reduction in cyclic capacity is observed with increased cycle number; there is rather a slight increase in cyclic capacity with cycle number indicating that a cyclic steady state still not has been reached after 50 cycles.

AbstractAn analysis of Italy's National Energy Budget of in the last decades shows the important role of the civil sector and the impact of fossil fuels in air conditioning systems. The high consumption of fossil fuel is Likely due to the predominance of plants with conventional boilers in buildings. Based on the analysis of the Exergy flow this paper proposes the Cogeneration technology for Air conditioning systems with heat pumps to implement the Rational Use of Energy. The feasibility of a retrofit intervention on existing systems of a large size is shown, by the projection of a cogeneration plant for the buildings of the University of Cagliari currently equipped with fossil fuel plants.

AbstractDuring the last decades significant effort has been put into research on the social, economical, political and technical issues related to large scale deployment of Carbon Capture and Storage (CCS). A complete CCS cycle requires safe, reliable and cost efficient solutions for transmission of CO2 from the capturing facility to the location of permanent storage. The current initiative originates from DNV’s long engagement in developing standards and guidelines for offshore pipelines and an identified need to specifically address the technical challenges related to transmission of CO2 with associated contaminants. The guideline will be based on a comprehensive literature review and gathering of experience from existing (both onshore and offshore) CO2 pipeline operators. Available pipeline codes, standards, guidelines and regulations combined with the latest available research and technical developments is set as the point of departure for this guideline development. Issues related to pipeline design, commissioning and operation as well as re-qualification/conversion of existing pipelines for transmission of CO2 will be addressed. The guideline is being developed as a joint industry project and is scheduled for delivery by end of July 2009. After completion of the JIP, the guideline will be converted into a public available Recommended Practice (RP) by Det Norske Veritas (DNV). The guideline will give “how to?” answers for safe, reliable and cost-effective transmission of CO2 in pipelines. This paper addresses main technical issues one need to manage.

AbstractIn the last years, the number of installed biofuels power plants is increased in northern Italy, due to favorable legislation on renewable energy sources, posing the issue to assess the resulting environmental effects. The European legislation on emissions for renewable fuels power plants provides guidelines to be integrated in the local regulations; moreover, local authorities have to identify the critical power plants in terms of pollution and the key parameters to grant licenses for the future plants.The aim of this paper is to describe a methodology and the calculation routine developed to assess the environmental effects of biomass plants in terms of simple indexes. The used approach is based on the Cross-Media Effects described by a European Commission Reference Document. In particular, several indexes are introduced to cover the most relevant environmental effects, as: air toxicity, global warming, acidification, eutrophication and photochemical ozone creation. For every considered pollutant (such as NOx, CO, etc.) directly emitted by the power plant, specific factors have been identified, in order to calculate the contribution to the different environmental indexes. Finally, a numerical evaluation of different biomass power plants, installed in Emilia Romagna region, is provided, in order to assess their environmental cross-media potential and to compare such kind of power plants with large scale, fossil-fuelled power plants.

AbstractAn absorption and desorption rig has been in operation at Telemark University College since 2010. The purpose of the rig is to perform measurements of CO2 removal efficiency and heat consumption at different process conditions like temperatures, flows and CO2 concentrations in the gas and the liquid. 30 wt-% monoethanolamine (MEA) in water has been the most used solvent. In earlier work, the heat consumption has been indirectly measured by the electricity consumption for steam production. In this work new results from 2012 and 2013 are presented where the steam consumption has been measured directly by a vortex flow meter.

AbstractEnvironment respect makes both the Legislator ever more careful to define urgent emissions limits than each one responsible to find the best technological and behavioral solutions. The works includes the results of combustion simulations in a MGT burner. The purpose is to verify combustion performances of some between classic and renewable fuels, with a view to design choices. The approaches: a “Laminar Flamelet” model and, especially to verify simply kinetic influences, a partially premixed model.

AbstractFor a commercial Carbon Capture and Storage (CCS) chain to be successful, it must satisfy a whole range of requirements: technical, economic, environmental, safety, and societal. A comprehensive, understandable and reproducible assessment of CCS projects is a complex task due to several reasons: wide range of actors and factors involved, substantial differences in the type and nature of both actors and factors, and numerous associated uncertainties. In this paper, a standardised methodology is described and illustrated on a few examples of relatively simple case studies. The proposed methodology provides means and tools for evaluation of several economic, environmental, and in the future also risk associated criteria and thereby enables selection of the most promising options for CCS. The methodology will also help to reduce the uncertainty by improving understanding of the most important dependencies and trends for the investigated key performance indicators as enlightened by the case studies examples. It could also help to design efficient incentives and measures to stimulate realization of CCS by identifying and evaluating the most important non-technical factors affecting the CCS chain viability.