Power Plant

The Chilean government has determined that a renewable energy quota of up to 10% of the electrical energy generated must be met by 2024. This plan has already sparked interest in wind, geothermal, hydro and biomass power plants in order to introduce renewable energy systems to the country. Solar energy is being considered only for demonstration, small-scale CSP plants and for domestic water heating applications. This apparent lack of interest in solar energy is partly due to the absence of a valid solar energy database, adequate for energy system simulation and planning activities. One of the available solar radiation databases is 20–40 years old, with measurements taken by pyranographs and Campbell–Stokes devices. A second database from the Chilean Meteorological Service is composed by pyranometer readings, sparsely distributed along the country and available from 1988, with a number of these stations operating intermittently. The Chilean government through its National Energy Commission (CNE) has contracted the formulation of a simulation model and also the deployment of network of measurement stations in northern Chile. Recent efforts by the authors have resulted in a preliminary assessment by satellite image processing. Here, we compare the existing databases of solar radiation in Chile. Monthly mean solar energy maps are created from ground measurements and satellite estimations and compared. It is found that significant deviation exists between sources, and that all ground-station measurements display unknown uncertainty levels, thus highlighting the need for a proper, country-wide long-term resource assessment initiative. However, the solar energy levels throughout the country can be considered as high, and it is thought that they are adequate for energy planning activities – although not yet for proper power plant design and dimensioning.

Experimental results are reported on simulataneous heat transfer and gas dissolution during the direct-contact condensation of steam on water in the presence of CO2. A column filled with structured packing is used as condenser with the water in counterflow with the steam/CO2 mixture. The region along the column where the bulk of condensation takes place is controllable by suitable choice of the steam/water ratio. Measured local heat-transfer coefficients change by roughly an order of magnitude from the bottom to the top of the column. The extent of CO2 dissolution in the water/condensate under most conditions is unexpectedly high and depends strongly on the exit liquid temperature. A driving force based on the interfacial CO2 concentration, not the overall concentration difference used in conventional absorption operations, is suggested as more appropriate to describe the phenomenon. The data are complemented with preliminary results from a computational model based on the integration along the column of local heat- and mass-transfer rates.

This paper presents the results of an investigation into the failure of steel tubes in a super heater boiler used at one of Kuwait Electrical and Power plant. The material of the tubes has suffered localized overheating, probably as a result of local heat flux impingement phenomenon, caused by gas or oil burners. This phenomenon gave rise to a rapid steam formation causing steam blanketing. It also prevented the accessibility of the water to the tube materials and consequently local, prolong, overheating took place, in which the temperature rose up to 700°C in a frequent manner for long time. The investigation has indicated that the failure attributed to the formation of thick scale of magnetite at the inner surface of the tube wall.The increase of the temperature is clearly shown in the microstructure of the tube at the stress rupture site, where ferrite matrix with spheroidized carbide particles were presented rather than only ferrite matrix with pearlites structure. Consequently, the properties of the materials of the tube have changed from its original values with respect to the design values of the tube due to the effect of the localized prolong overheating. Therefore, the original design values are no longer valid and the materials of the tube failed in a premature manner, at less than 250,000 hours.

In this work, low temperature Organic Rankine Cycles are studied as bottoming cycle in medium and large scale combined cycle power plants. The analysis aims to show the interest of using these alternative cycles with high efficiency heavy duty gas turbines, for example recuperative gas turbines with lower gas turbine exhaust temperatures than in conventional combined cycle gas turbines. The following organic fluids have been considered: R113, R245, isobutene, toluene, cyclohexane and isopentane. Competitive results have been obtained for toluene and cyclohexane ORC combined cycles, with reasonably high global efficiencies.The paper is structured in four main parts. A review of combined cycle and ORC cycle technologies is presented, followed by a thermodynamic analysis of combined cycles with commercial gas turbines and ORC low temperature bottoming cycles. Then, a parametric optimization of an ORC combined cycle plant is performed in order to achieve a better integration between these two technologies. Finally, some economic considerations related to the use of ORC in combined cycles are discussed.

A new classification method, for isolating steam generator tube defects in nuclear power plants using Eddy Current Test (ECT) signals, has been developed. The method uses Self-Organizing maps (SOM) with different data signatures to identify and classify these defects. A multiple inference system is proposed which evaluates different extracted characteristic SOMs to infer the defect type. Wavelet zero-crossing representation, a linear predictive coding (LPC), and other basic signal representations, such as magnitude and phase, are used to construct characteristic vectors that combine one or more of these features. These vectors are evaluated for their ability to classify tube defects and the ones with the best performance are used in the multiple inference system. The effectiveness of the method is demonstrated by applications of the characteristic maps to ECT data from various cases of tube defects in pressurized water reactor plant steam generators. The developed algorithm enables real-time applications such as fast tube defects classification systems and visualization of ECT signal feature prototypes, which may improve the speed of time-critical decision making during power plant maintenance outages.

The aim of this study was to identify the hazards, evaluate their risk factors and determine the measure for promotion of the process and reduction of accidents in the chemical unit of the power station. In this case and qualitative study, HAZOP technique was used to recognize the hazards and problems of operations on the chemical section at power station. Totally, 126 deviations were documented with various causes and consequences. Ranking and evaluation of identified risks indicate that the majority of deviations were categorized as "acceptable" and less than half of that were "unacceptable". The highest calculated risk level (1B) related to both the interruption of acid entry to the discharge pumps and an increased density of the acid. About 27% of the deviations had the lowest risk level (4B). The identification of hazards by HAZOP indicates that it could, systemically, assess and criticize the process of consumption or production of acid and alkali in the ch...

The efficiency of conventional boiler/steam turbine fossil power plants is a strong function of steam temperature and pressure. Since the energy crisis of the 1970s, research to increase both has been pursued worldwide. The need to reduce carbon monoxide emissions has provided further incentive to improve efficiency. The main enabling technology is the development of stronger high temperature materials especially

The activities overview of Russian laboratories on Heavy-Ion Fusion is presented. The new data on development of the power plant concept based on direct drive of cylindrical DT target by intense 500 MeV/u ion beam in fast ignition mode and two sections wetted liquid wall reactor chamber with lithium-lead blanket are presented. A heavy-ion driver system providing consequent compression and ignition of the cylindrical DT target is described. Data on repetitive energy fluxes generated by the 750 MJ of microfusion explosion are given. The design of the thin liquid wall reactor chamber is specified. The behavior of the liquid film at the first wall and the blanket material under a pulsed energy flux loading is emphasized. The energy conversion thermal scheme and power plant output parameters are presented. The state of the art of the ITEP-TWAC accelerator facility operation and new results of current beam-plasma interaction experiments are discussed. This work has been done under the auspices of the Scientific Council of Russian Academy of Sciences "Analysis of Energy Systems" under the chairmanship of academician V.I. Subbotin.

Harmful ecological effects caused by the emission of gaseous pollutants like sulfur dioxide (SO2) and nitrogen oxides (NOx), can be reduced by load adequate distribution between power plants. However, this leads to a noticeable increase in their operating cost. In order to eliminate this conflict, and to study the trade-off relation between fuel cost and emissions, an approach to solve this multiobjective environmental/economic load dispatch problem, based on an efficient successive linear programming technique is proposed. Simulation results on the Algerian 59-bus power system prove the efficiency of this method thus confirming its capacity to solve the environmental/economic power dispatch problem.

... As determined by EDS, the predominant elements in the fly ash samples were silicon, aluminum,iron, calcium and oxygen in various compounds. ... [16] suggested that the iron in the alumino-silicate glassy phase in fly ash is the source of bioavailable iron in urban areas. ...