Session: 08-02-01: Fundamentals and Applications of Thermodynamics

Paper Number: 70521

Start Time: Wednesday, 10:55 AM

70521 - Conventional and Advanced Exergetic Analysis for the Combined Cycle of Power Plant With Gas Turbine of a Refinery and Advanced Exergetic Analysis for the Combined Cycle of Power Plant With Gas Turbine of a Refinery. 

This article shows the results of the study of the performance of a combined cycle plant conformed by Siemens STG-800 gas turbine designed to produce 47.5 MW of electricity under ISO conditions and a MACCHI heat recovery boiler (HRSG) that produces 81908 kg /h of steam. The system is part of the steam and electric power generation section of a refinery in the city of Cartagena de Indias.

Taking into account the typical conditions of the location differ from the ISO conditions, it is necessary to obtain information about the performance in these conditions of each one of the equipment. Consequently, this research have been organized as follows: First, basic thermodynamics at equipment limits are made, then energy balances for each component and performance parameters are defined. This allows us to compare the fit of the thermodynamic model with the values provided by the manufacturer. The exergy destruction rate and the exergy efficiency for each component and the total system are obtained from the exergy balances.

Factors, such as incrustation, erosion, imbalance and inadequate maintenance schedules affects the efficiency of the equipment, therefore these degradation parameters should be included in the investigation as a function of time. The maintenance application seeks to return the efficiency equipment loss due to these parameters, however, many maintenance plans does not consider that it is not possible to recover all the efficiency loss and its execution does not take into account the operation status in which the cost-benefit ratio is the most optimal and neither does the performance interaction between equipment.

The purpose of this research is to quantify inefficiencies in each of the equipment and how these affects each of the other equipment. This is accomplished from the application of advanced exergetic analysis from which the avoidable, unavoidable, endogenous and exogenous exergies and also the crossed ones and finally the mexogenous exergetic analysis were obtained. These results allowed to know the amount of energy loss is the result of inefficiencies of the environment, of the same equipment and those that due to the technological capabilities cannot be recovered.

The model fits with an average error of 2%, the KPI’s used were net power, heat rate and thermal efficiency, from the conventional exergetic analysis it was obtained that the destruction of exergy reaches 83.5MW being 15% of this avoidable, 82% of destruction is caused by inefficiencies within the system. From the mexogenous result, it was gained that the inefficiencies of the compressor affect the rest of all equipment. Focusing efforts on improving its conditions can recover up to 25% of the total destruction.

Presenting Author: Juan Fajardo Universidad Tecnológica De Bolívar

Authors:

Juan Fajardo Universidad Tecnológica de Bolívar
Dawing Guette Universidad Tecnologica de Bolivar
Deibys Barreto Universidad Tecnologica de Bolivar
Camilo Cardona ECOPETROL
Ildefonso Baldiris SENA-Centro Internacional Náutico, Fluvial y Portuario