The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
An accurate description of the geometry of the temperature-entropy (T–S) diagram is of fundamental importance for predicting the state of working fluids undergoing isentropic processes, as usually required for analyzing the performance of refrigeration and power generation systems. In this contribution, rigorous analytical expressions have been obtained for the first and second temperature derivatives...
This paper presents the results of exergetic and environmental analysis of a typical pulverized coal power plant located in Brazil. The goal was to quantify both the exergy destruction and the environmental impact associated with a thermal power plant. The problem boundary consists of the entire coal delivery route, including mining and beneficiation, transport, pre-burning processes and the power...
Mixed-Integer Linear Programming (MILP) has been generally used in the recent past to evaluate the optimal operation of heat storage systems for district heating. In fact, model equations and constraints can be linearized to strongly reduce the computational time without a significant loss in accuracy, and other simplifying hypotheses can be introduced, such as the constant value of the heat storage...
Coal based polygeneration, a technology that couples power generation and chemical production, is a promising solution to the challenges of fossil fuel depletion and greenhouse gas emissions. Carbon monoxide shift process is a key unit in polygeneration, which adjusts hydrogen and CO ratio according to the requirements of downstream processes. Usually steam is added to shift the gas composition extensively,...
Chemical absorption is a very effective and nowadays often used method of gas separation in chemical industry. This method is also often taken into account when considering systems of carbon capture from flue gases of coal-fired power plants. This process is very energy-intensive and significantly reduces the performance of the power plant.In the paper, the integration of a coal-fired power plant...
Waste heat recovery from the exhaust gases of gas turbines, geothermal resources, and from industrial plants offers a great opportunity for rational energy usage by productively converting the waste energy. In the present communication we report a systematic study starting with the hydrocarbons for the different temperature ranges at which the waste heat is available from high, medium, or low temperature...
An air-cooled two-stage NH3-H2O absorption refrigeration system is proposed for potential application of residential small scale cooling system driven by solar heated hot water. It can reduce the initial fabrication and maintenance costs of both the solar collection system and the absorption chiller. An experimental prototype for 2 kW cooling capacity has been built to investigate the feasibility...
Nuclear energy can play a very significant long-term role for meeting the world’s increasing energy demands, while simultaneously addressing challenges associated with global climate and environmental impact. Many nations of the world, particularly the Asia/Pacific Rim countries, are actively engaged in a major expansion of their nuclear energy complex. The degree to which nuclear energy can address...
An advanced exergoenvironmental analysis combines an advanced exergetic analysis with a life cycle assessment. This allows the environmental impacts of an energy conversion system to be split into avoidable/unavoidable and endogenous/exogenous parts, revealing improvement potential and component interactions. This paper presents the application of an advanced exergoenvironmental analysis to a combined-cycle...
In the present paper, a five-column heat integrated methanol distillation scheme is proposed with the aid of process simulation and pinch analysis. Unlike the popular four-column (or 3 + 1 column) scheme, a medium-pressure column is added after the light ends column in this novel scheme. The overhead vapor of the medium-pressure column integrates with the light ends column, and an inter-reboiler is...
In this study, energy and exergy analyses of a biomass trigeneration system using an organic Rankine cycle (ORC) are presented. Four cases are considered for analysis: electrical-power, cooling-cogeneration, heating-cogeneration and trigeneration cases. The results obtained reveal that the best performance of the trigeneration system considered can be obtained with the lowest ORC evaporator pinch...
The paper discusses chosen issues concerning damaged gas pipelines. Attention is paid to modelling the steady-state flow of natural gas in distribution pipelines, and the most commonly applied models of isothermal and adiabatic flow are evaluated for both the ideal and the real gas properties. A method of accounting for a leakage by means of a reference flow equation with a discharge coefficient is...
A numerical optimisation method, previously applied to a large industrial cogeneration plant, has been adapted for a small-scale unit that must be driven by the heat demand of a medium-size building located in the north of Portugal. The unit is based on a micro-gas turbine and includes an internal pre-heater (typical of these types of small-scale units) and a water heater. The mathematical model yields...
Commercially available thermoelectric modules are useful devices to recover low-temperature waste heat for power generation. To understand the characteristics of power generation from thermoelectric modules (TEMs), the performances of TEMs at various flow patterns, heating temperatures, flow rates of water and numbers of modules in series are studied experimentally. The results show that the effects...
The cement industry is one of the leading producers of anthropogenic greenhouse gases, of which CO2 is the most significant. Recently, researchers have invested a considerable amount of time studying ways to improve energy consumption and pollutant formation in the overall cement manufacturing process. One idea involves dividing the calcination and clinkering processes into two separate furnaces....
The development of Enhanced Geothermal Systems (EGS) for the cogeneration of electricity and district heating is expected to be important in the future. The criteria to be accounted for in the energy conversion system design are the economic profitability, the thermodynamic efficiency in the usage of the resource, and the generated life-cycle environmental impacts, which are as well a key point for...
A possibility of simplification of the scattering phase function of a pulverized coal flame was analyzed in the paper. It was showed that the type of radiation scattering of a pulverized coal flame is between two limiting cases: isotropic and forward scattering. A comprehensive mathematical model of a tangentially fired furnace by pulverized coal was formed. Radiative heat transfer was modeled using...
In this research, the impact of the European Emission Trading Scheme (EU ETS) on the corporate value of European electricity corporations has been measured, and a comparison study of the impact between phase I and phase II of the EU ETS has been performed. To achieve this, a modified multifactor market model has been used to investigate how the development of EU emission allowance (EUA) prices has...
Coal gasification is seen as an attractive way for hydrogen production. The main advantage of this approach is the low fuel price compared to reforming of natural gas. On the other hand, considering the EU climate policy, the emission of CO2 has to be reduced. The CO2 capture from the raw syngas should be thus considered. The main purpose of this work is to propose implementation of a fully “zero-emission”...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.