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Growth in engineering thermoplastic recycling has been slow over the past decade because the current technologies based on solid-state re-polymerization of degraded feedstock do not offer a cost advantage over the use of virgin materials. As a result, most recycling efforts focus on using degraded post-industrial or post-consumer plastics in low cost, low performance applications, such as fiber and...
Temporary variation for the demand of refining products which are used in the Mexico City Metropolitan Area (MCMA) is presented. Its consequent energy contribution is evaluated from 1988 to 2000. The annual estimation was integrated from a detailed inventory of fuels volume, so as the calculus of its respective energy equivalence. The fuel quality specifications, which have been required by regional...
This paper illustrates a methodology developed to facilitate the analysis of complex systems characterized by a large number of technical, economical and environmental parameters. Thermo-economic modeling of a natural gas combined cycle including CO 2 separation options has been coupled within a multi-objective evolutionary algorithm to characterize the economic and environmental performances...
The chemical exergy of a substance is the maximum work that can be obtained from it by taking it to chemical equilibrium with the reference environment at constant temperature and pressure. This exergy is normally taken or calculated from tabulated values obtained for standard conditions, i.e. an ambient temperature of 298.15K, an atmospheric pressure of 1 atm, and a model of reference species which...
A separation process of carbon isotopes, 12 C (98.9%), 13 C (1.1%) and 14 C (trace), by the chemical exchange reactions between CO 2 and amine carbamate was designed by the exergy analysis technique and the applicability of the exergy analysis to the design of isotope-separation process is discussed. The exergy loss (EXL) for the single-column process was increased...
Stored energy can provide electricity during periods of high demand, as currently demonstrated with bulk storage systems such as pumped hydro storage (PHS), which accounts for only 2.5% of the current installed base load in the USA. Sites for future developments have become less available, and environmental siting issues, as well as high costs have stopped further prospects. This paper looks at the...
Carbon capture is often discussed in the literature with the sole focus on power processes, despite the fact that carbon dioxide emissions from other sources are just as relevant for the impact on the atmosphere. Furthermore, some carbon capture methods are relatively inefficient when applied to power production processes. Carbon capture should preferably be performed where the cost is as low as possible,...
Aim of this paper is to analyze the performance of an innovative high-efficiency steam power plant by means of two “life cycle approach” methodologies, the life cycle assessment (LCA) and the “extended exergy analysis” (EEA).The plant object of the analysis is a hydrogen-fed steam power plant in which the H 2 is produced by a “zero CO 2 emission” coal gasification process (the ZECOTECH...
This paper aims at analyzing the information that can be obtained by considering different accuracy levels in the thermoeconomic diagnosis problem. A progressive elimination of effects that impede a clear identification of anomalies causing performance degradation is performed. The analysis is applied to combined cycle plant.
Hydrogen produced from renewable biofuel is both clean and CO 2 neutral. This paper evaluates energy and net CO 2 emissions consequences of integration of hydrogen production from gasified black liquor in a chemical pulp mill. A model of hydrogen production from gasified black liquor was developed and integration possibilities with the pulp mill's energy system were evaluated in order...
Fuel cells have great application potential as stationary power plants, as power sources in transportation, and as portable power generators for electronic devices. Most fuel cells currently being developed for use in vehicles and as portable power generators require hydrogen as a fuel. Chemical storage of hydrogen in liquid fuels is considered to be one of the most advantageous options for supplying...
The liberalization of the electricity sector requires utilities to develop sound operation strategies for their power plants. In this paper, attention is focused on the problem of optimizing the management of the thermal power plants belonging to a strategic producer that competes with other strategic companies and a set of smaller non-strategic ones in the day-ahead market. The market model suggested...
The simulation and exergy analysis of a hybrid Solid Oxide Fuel Cell–Gas Turbine (SOFC–GT) power system are discussed in this paper. In the SOFC reactor model, it is assumed that only hydrogen participates in the electrochemical reaction and that the high temperature of the stack pushes the internal steam reforming reaction to completion; the unreacted gases are assumed to be fully oxidized in the...
Artificial neural network is a powerful tool in the forecast of solar irradiance. In order to gain higher forecasting accuracy, artificial neural network and wavelet analysis have been combined to develop a new method of the forecast of solar irradiance. In this paper, the data sequence of solar irradiance as samples is mapped into several time-frequency domains using wavelet transformation, and a...
The rational use of energy became a priority for all industries in Brazil after the energetic rationing in 2001. The aim of this work is to assess a proposal of a power generation system for Companhia Siderúrgica Tubarão, a steel mill plant. The current system is based on a regenerative Rankine cycle using two gases from steel production—blast furnace gas (BFG) and coke oven gas (COG)—to generate...
The optimization of the heat recovery steam generator (HRSG) is one of the key elements for increasing the efficiency of combined plants. According to the current technical practice, it can be organized at different levels of complexity with objectives sequentially defined: operating parameters, geometrical details and technological elements.According to this point of view, in the paper a complete...
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