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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.

Abstract This paper characterized the wood pellet and torrefied wood pellet fuel as compared to coal for 100 MW co-firing power generation plant. There were five experiments to characterise the chemical and physical properties of coal, wood pellet and torrefied wood pellet namely moisture analysis, Thermo gravimetric Analyser (TGA), Bomb Calorimeter, Organic Elemental Analyser and Scanning Electron Microscope (SEM). The moisture analysis result from moisture analyser and TGA shows that the moisture content of torrefied wood pellet is lower than wood pellet at 6.760% and 3.629%. Moreover, the volatile matter, hydrogen and nitrogen content of torrefied wood pellet is lower than wood pellet at 65.20%, 5.993% and 0.4078% correspondingly. The calorific value, fixed carbon content, ash and sulphur also increase in torrefied wood pellet at 20.68 MJ/kg, 28.85%, 2.321% and 0.1656% respectively. In general, torrefaction improve the fuel properties of wood pellet similar to coal. The 100 MW direct co-firing power plant provides less capital investment, operation and maintenance cost for low rate co-firing ratio. However, there is economic challenges for high rate co-firing substation of torrefied wood pellets.

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.

“Off-the-shelf” devices have attracted much consideration lately, especially in emulsions production in droplet-based microfluidics. While many simple and cost-effective designs have been proposed and demonstrated, the functionability of these purported simple devices has been questioned, especially in emulsions generation for commercial scale. In this work, a simple needle-based device was used in the production of functional core-shell microcapsules of uniform sizes, typically in the range of 600 to 720 µm, and shell thickness of 20 to 110 µm, and C.V of 0.97 to 3.0%. These core-shell microcapsules are a new form of carbon capture materials, with carbon solvent encapsulated in thin polymeric shell. The microcapsules synthesized were subjected to absorption-desorption tests. This work has successfully demonstrated the use of off-the-shelf microdevice and its reliability for the production of functional microcapsules.