The objective of this applied industrial research was to conduct an exergy-based analysis for an Open Cycle Gas Turbine in Abu Dhabi in order to evaluate its performance under design conditions and during summer weather conditions.
The first explanation for this investigation is that CO2 emissions from power generation plants in the United Arab Emirates are responsible for about 33% of the 200 million tons of the total CO2 emitted in 2013 in the country. The second reason for this industrial project is that the standard conditions used for the design of gas turbines are 288K, sea level atmospheric pressure and 60% relative humidity. However, the average summer weather conditions in Abu Dhabi are T=316K and a relative humidity of 50%. As a consequence, the effects of summer weather conditions on different performance indices of the power plant were also studied.
Table of Contents
Introduction
Background
Concept of Exergy
Standard Chemical Exergy of a gas mixture
Exergy Balance in Open Systems
Exergy analysis of an Open Cycle Gas Turbine
Economic analysis
Exergoeconomic analysis
Cost of exergy destruction
Exergoenvironmental analysis
Plant Description
Natural Gas Specifications
Ambient Air Specifications
Power Plant Evaluation
Exergy Analysis
Exergoeconomic Analysis
Exergoenvironmental analysis
Validation of the simulation results
Analysis of Results
Exergy Analysis
Exergoeconomic Analysis
Exergoenvironmental Analysis
Recommendations
Research Objectives and Themes
The primary objective of this research is to evaluate the performance of an Open Cycle Gas Turbine (OCGT) in Abu Dhabi through comprehensive exergy-based, exergoeconomic, and exergoenvironmental analyses, specifically comparing standard design conditions with actual summer weather conditions to assess efficiency losses and environmental impacts.
- Exergy analysis of power plant components under varying environmental conditions.
- Economic assessment using the Specific Exergy Costing (SPECO) method.
- Environmental impact quantification using the Eco-indicator 99 life cycle methodology.
- Performance optimization strategies to mitigate the effects of high ambient temperatures.
Excerpt from the Book
Concept of Exergy
Exergy is commonly defined as the maximum theoretical work that can be extracted from a “combined system” consisting of a “system” under study and its “environment” as the system passes from an initial state to a state of equilibrium with the environment [8]. When a system is in equilibrium with the environment, the state of the system is called ‘dead state’ and its exergetic value is zero. According to Bejan et al.[7], total exergy (ET) of a stream is constituted by four main components:
The physical exergy (Eph) is often described as the maximum theoretical useful work obtainable as the system passes from its initial state (P, T) to the “restricted dead state” (P0, T0). On the other hand, the chemical exergy (Ech) is the maximum useful work obtainable as the system passes from the “restricted dead state”, where only the conditions of mechanical and thermal equilibrium are satisfied, to the “dead state” where it is in complete equilibrium with the environment [9]. The kinetic (Ek) and potential (Ep) exergies are associated to the system velocity and height, respectively measured relative to a given reference point. When a system is at rest relatively to the environment (Ek=Ep=0), the total mass specific exergy (eT) of a stream is defined as:
Summary of Chapters
Introduction: Outlines the theoretical necessity of using exergy analysis to evaluate thermodynamic inefficiencies and environmental impacts in energy conversion systems.
Background: Defines the fundamental thermodynamic concepts, including exergy, exergy balances in open systems, and the application of these theories to gas turbines.
Economic analysis: Details the economic modeling approach, focusing on purchased equipment costs and capital recovery factors for power plant components.
Exergoeconomic analysis: Explains the cost balance methodology and how to approximate the cost of exergy destruction within individual components.
Exergoenvironmental analysis: Describes the integration of Life Cycle Assessment (LCA) with exergy analysis to quantify environmental impacts using Eco-indicator metrics.
Plant Description: Provides technical specifications of the power plant, natural gas composition, and ambient air properties in Abu Dhabi.
Power Plant Evaluation: Presents the calculated results of exergy, economic, and environmental parameters for the power plant under design and summer conditions.
Validation of the simulation results: Compares the simulation data against operational benchmarks to ensure the accuracy and reliability of the model.
Analysis of Results: Interprets the findings regarding how summer conditions negatively impact the combustor and compressor while noting the compensatory performance of the turbine.
Recommendations: Suggests practical engineering interventions, such as inlet cooling and mechanical cleaning, to enhance performance and reduce environmental impact.
Keywords
Exergy analysis, Gas Turbine, Abu Dhabi, Exergoeconomic, Exergoenvironmental, Eco-indicator 99, Summer weather conditions, Combustor, Turbine, Compressor, Sustainability, Energy efficiency, Environmental impact, Cost balance, SPECO method
Frequently Asked Questions
What is the primary focus of this research?
This research focuses on evaluating the performance, economic costs, and environmental impacts of an Open Cycle Gas Turbine located in Abu Dhabi, specifically comparing standard design conditions with extreme summer weather conditions.
What are the central thematic areas?
The central themes include exergy-based thermodynamics, exergoeconomics (cost-benefit analysis of exergy), and exergoenvironmental analysis (quantifying life cycle environmental impacts).
What is the main objective of the study?
The primary objective is to determine how summer atmospheric conditions affect the efficiency and cost-effectiveness of a power plant and to identify specific components where performance improvements can be made.
Which scientific methods are applied?
The study utilizes the Second Law of Thermodynamics (exergy analysis), the Specific Exergy Costing (SPECO) method for economic evaluation, and Life Cycle Assessment (LCA) using the Eco-indicator 99 framework.
What does the main body cover?
The main body covers the mathematical modeling of the power plant components, the specific performance indices (such as exergy destruction ratio and relative cost difference), and the simulation of these parameters under standard versus summer conditions.
Which keywords characterize this work?
Key terms include Exergy analysis, Gas Turbine, Exergoeconomics, Exergoenvironmental, Sustainability, and Environmental impact.
How do summer weather conditions affect the combustor?
The study finds that summer weather conditions increase the exergy destruction ratio of the combustor by 21.2% and decrease its exergetic efficiency, identifying it as the main contributor to performance loss.
What recommendations are made for the turbine section?
Because the turbine experiences improved exergetic efficiency during summer due to higher temperatures, it is suggested to install a heat recovery steam generator (HRSG) to utilize exhaust gas heat for additional power production.
Why is the compressor identified for improvement?
The compressor's performance is negatively affected by high ambient temperatures; the study suggests adding an inlet cooling system to bring intake air closer to standard conditions.
- Arbeit zitieren
- Zin Eddine Dadach (Autor:in), 2017, Performance indices of a power plant using exergy-based analyses, München, GRIN Verlag, https://www.hausarbeiten.de/document/379719
