Showing papers by "Umberto Desideri published in 2000"

Assessment of LNG Regasification Systems With Cogeneration

Abstract: Natural gas is usually transferred to consumers through pipelines, which may cover distances of thousands of kilometers. In some cases, however, when the path of the pipelines crosses seas or countries where the politic situation does not ensure a continuous and reliable flow, other means of transportation are preferred. In these cases, the natural gas is liquefied and transported in tankers, which load the tanks at liquefaction plants and discharge them at regasification plants. This gives a considerable chance to differentiate supply sources and allows gas imports from producing countries that are otherwise inaccessible via pipeline.The aim of this paper is the study of systems, which carry out liquefied natural gas (LNG) vaporization using cogenerative solutions. The following configurations were studied in particular:• Gas-steam combined cycles;• Closed gas-gas combined cycles using three different working fluids.Two typical plant sizes and two gas pressure sendout levels (7.3 MPa for long distance pipeline networks and 2.5 MPa for terminals linked to power production plants with combined cycles) have been analyzed. The suggested solutions have been optimized, and performance calculated. The discussion is completed by a simplified economic analysis.Copyright © 2000 by ASME

LO.CO.MO.DIA. Low Cost Monitoring for Diagnostic Purposes of a Small Scale CHP Plant

Abstract: Small scale Internal Combustion Engines (ICE) powered Combined Heat and Power (CHP) plants are economically convenient when availability and efficiencies are above specified limits. Nevertheless these plants are often run without a monitoring device capable of data storing and trending and of performance evaluation. This paper describes the setting up of a powerful low-cost monitoring system for the CHP plant that powers the School of Engineering of the University of Perugia. Data acquisition is performed by interfacing a Personal Computer (PC) to existing control panels via, serial port, and to a data acquisition board for those variables that are not measured by existing devices. Performance indexes are then calculated via software. Alarms and controls are stored as well to set up a database for diagnostic purposes. The monitoring itself has already shown its troubleshooting capability in interface to maintenance personnel: history trending of variables speeds up the phase of failure identification because it eliminates those possibilities that are negated by cross referencing values of different variables.