Analysis of a Combined Gas Turbine and Absorption-Refrigeration Cycle

1971 ◽  
Vol 93 (1) ◽  
pp. 28-32
Author(s):  
M. M. Nagib
Keyword(s):  
Gas Turbines ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Absorption Refrigeration ◽  
Ambient Temperatures ◽  
Compressor Pressure Ratio ◽  
Average Improvement ◽  
Refrigeration Unit ◽  
Compressor Inlet

An appreciable improvement in the performance of gas turbines operating with ambient temperatures above 90 deg F could be achieved by combining an absorption-refrigeration unit to the power cycle. The thermal energy in the exhaust gases from the turbine is used to operate the refrigeration unit, which in turn cools the air prior to entering the compressor. This reduction in compressor-inlet temperature results an average improvement of about 7–9 points in the thermal efficiency of the combined cycle as well as an increase in the specific output. The analysis includes the effect of different cycle parameters such as compressor pressure ratio, maximum cycle temperature, and regeneration.

Genetic Optimization of Steam Injected Gas Turbine Power Plants

2002 ◽  
Author(s):  
Ibrahim Sinan Akmandor ◽  
O¨zhan O¨ksu¨z ◽  
Sec¸kin Go¨kaltun ◽  
Melih Han Bilgin
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Power Plants ◽  
Pressure Ratio ◽  
Steam Injection ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Compressor Pressure Ratio

A new methodology is developed to find the optimal steam injection levels in simple and combined cycle gas turbine power plants. When steam injection process is being applied to simple cycle gas turbines, it is shown to offer many benefits, including increased power output and efficiency as well as reduced exhaust emissions. For combined cycle power plants, steam injection in the gas turbine, significantly decreases the amount of flow and energy through the steam turbine and the overall power output of the combined cycle is decreased. This study focuses on finding the maximum power output and efficiency of steam injected simple and combined cycle gas turbines. For that purpose, the thermodynamic cycle analysis and a genetic algorithm are linked within an automated design loop. The multi-parameter objective function is either based on the power output or on the overall thermal efficiency. NOx levels have also been taken into account in a third objective function denoted as steam injection effectiveness. The calculations are done for a wide range of parameters such as compressor pressure ratio, turbine inlet temperature, air and steam mass flow rates. Firstly, 6 widely used simple and combined cycle power plants performance are used as test cases for thermodynamic cycle validation. Secondly, gas turbine main parameters are modified to yield the maximum generator power and thermal efficiency. Finally, the effects of uniform crossover, creep mutation, different random number seeds, population size and the number of children per pair of parents on the performance of the genetic algorithm are studied. Parametric analyses show that application of high turbine inlet temperature, high air mass flow rate and no steam injection lead to high power and high combined cycle thermal efficiency. On the contrary, when NOx reduction is desired, steam injection is necessary. For simple cycle, almost full amount of steam injection is required to increase power and efficiency as well as to reduce NOx. Moreover, it is found that the compressor pressure ratio for high power output is significantly lower than the compressor pressure ratio that drives the high thermal efficiency.

Thermodynamic Evaluation of Advanced Combined Cycle Using Latest Gas Turbine

2003 ◽  
Author(s):  
Sanjay ◽  
Onkar Singh ◽  
B. N. Prasad
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Specific Work ◽  
Thermodynamic Evaluation ◽  
Compressor Pressure Ratio ◽  
Steam Cooling ◽  
Plant Efficiency

The present work deals with the thermodynamic evaluation of combined cycle with re-heat in gas turbine using the latest gas turbines namely ABB GT26 gas turbine (advanced) in which reheat is used and the blade cooling is done by air bled from compressor. The same turbine is subjected to closed loop steam cooling. Parametric study has been performed on plant efficiency and specific work for various independent parameters such as turbine inlet temperature, compressor pressure ratio, reheating pressure ratio, reheater inlet temperature, blade temperature, etc.. It has been observed that due to higher compressor pressure ratio involved in reheat gas turbine combined cycle and higher temperature of exhaust, the plant efficiency and specific work are higher with the advanced reheat gas/steam combined cycle over the simple combined cycle. Steam cooling offers better performance over aircooling.

Power Augmentation Approaches for Mechanical Drive Turbines

2013 ◽  
Author(s):  
Cyrus B. Meher-Homji ◽  
Mustapha A. Chaker
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Oil And Gas ◽  
Water Injection ◽  
Inlet Temperature ◽  
Process Industries ◽  
Ambient Temperatures ◽  
Compressor Inlet ◽  
Cooling Technology ◽  
Selection Of

Mechanical drive gas turbine can benefit significantly by power augmentation. In the oil and gas, petrochemical and process industries, the reduction in output of mechanical drive gas turbines curtails plant output or throughput. Gas turbines exhibit a drop in power output with an increase in air compressor inlet temperature of the order of 0.7% / °C for heavy duty gas turbines and approximately 1% / °C for aeroderivative turbines. Power augmentation by inlet cooling is an attractive means to minimize production swings. Designing gas turbine driven refrigeration compressors for high ambient temperature swings is also a design challenge due to power limitations at high ambient temperatures and high refrigerant condensing pressures. This paper will address a range of gas turbine inlet cooling techniques, and provide a technical perspective of different inlet cooling approaches. Technical approaches including inlet evaporative cooling, inlet fogging, wet compression, inlet mechanical and absorption chilling are covered. Other approaches such as water injection are briefly discussed. The judicious selection of the dry bulb temperature and coincident relative humidity for the design and selection of the cooling technology is discussed.

scholarly journals The Constant Volume Gas Turbine: A Thermodynamic Assessment

1974 ◽  
Author(s):  
M. Zockel
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Constant Pressure ◽  
Pressure Ratio ◽  
Constant Volume ◽  
Specific Power ◽  
Inlet Temperature ◽  
Turbine Efficiency ◽  
Compressor Pressure Ratio

A quasi-steady-state analysis is made of the performance of a gas-turbine working with intermittent, constant volume combustion. Variables considered include inlet temperature, compressor pressure ratio, scavenge ratio, combustion time, heat exchanger thermal ratio. Characteristics are computed over a full loading range. Computations are based on turbines having the following behavior: (a) constant turbine efficiency, (b) characteristics of a multistage axial turbine, and (c) characteristics of a single-stage radial turbine. The analysis indicates that the constant volume gas turbine has advantages in thermal efficiency, specific power and part load performance over constant pressure gas turbines operating at the same compressor pressure ratio and turbine inlet temperature. However, the addition of a heat exchanger shows less advantage when applied to a constant volume than to a constant pressure engine.

Performance Enhancement of One and Two-Shaft Industrial Turboshaft Engines Topped With Wave Rotors

2018 ◽  
Vol 35 (2) ◽  
pp. 137-147 ◽  
Author(s):  
Antonios Fatsis
Keyword(s):  
Gas Turbines ◽  
Performance Enhancement ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Specific Work ◽  
Wave Rotor ◽  
Wave Rotors ◽  
Compressor Pressure Ratio ◽  
Industrial Gas Turbines ◽  
The One

Abstract Wave rotors are rotating equipment designed to exchange energy between high and low enthalpy fluids by means of unsteady pressure waves. In turbomachinery, they can be used as topping devices to gas turbines aiming to improve performance. The integration of a wave rotor into a ground power unit is far more attractive than into an aeronautical application, since it is not accompanied by any inconvenience concerning the over-weight and extra dimensioning. Two are the most common types of ground industrial gas turbines: The one-shaft and the two-shaft engines. Cycle analysis for both types of gas turbine engines topped with a four-port wave rotor is calculated and their performance is compared to the performance of the baseline engine accordingly. It is concluded that important benefits are obtained in terms of specific work and specific fuel consumption, especially compared to baseline engines with low compressor pressure ratio and low turbine inlet temperature.

A critical analysis of the thermodynamic advantages of reheat in gas turbines

1998 ◽  
Vol 212 (2) ◽  
pp. 81-87 ◽  
Author(s):  
R I Crane
Keyword(s):  
Gas Turbines ◽  
Recent Literature ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Exhaust Temperature ◽  
Turbine Performance ◽  
Compressor Pressure Ratio ◽  
New Generation ◽  
Use Of Models ◽  
Selection Of

Apparently conflicting ideas on the effects of reheat on gas turbine performance can be obtained when comparing thermodynamics textbook treatments with recent literature on the new generation of reheat machines. These are resolved through the use of models with varying degrees of realism. The models are built with ‘live mathematics’ software which makes it straightforward to incorporate additional irreversibilities and less-simplified gas property relationships, and can be more effective than algebraic analyses for demonstrating the effect of cycle parameters. It is shown how the sign of the change in overall efficiency due to reheat depends on pressure and temperature ratios and on compressor and turbine efficiencies, and why a high compressor pressure ratio is beneficial. The trade-off between gains in specific net work and efficiency, by selection of the reheating pressure, is illustrated, the current relevance of the value that maximizes net work, traditionally termed ‘optimum’, is questioned and it is demonstrated that an exhaust temperature suitable for combined cycle operation requires a higher reheating pressure. Further results show how fuel consumption and gross power are divided between high- and low-pressure combustors and turbines respectively.

Thermoeconomic Analysis of Micro Gas Turbine Design in the Range 25–500 kWe

2010 ◽  
Author(s):  
Leandro Galanti ◽  
Aristide F. Massardo
Keyword(s):  
Gas Turbines ◽  
Pressure Ratio ◽  
Economic Value ◽  
Capital Cost ◽  
Inlet Temperature ◽  
Micro Gas Turbine ◽  
Compressor Pressure Ratio ◽  
Cost Parameters ◽  
Turbine Design ◽  
The University

The main aim of this paper is the thermoeconomic analysis of micro gas turbines in the range 25–500 kWe. This thermoeconomic analysis is based on the Thermoeconomic Functional Analysis (TFA) approach developed by the Authors over the last twenty years and is strongly related to the need for minimizing of the specific capital cost which is still considered high, and for optimizing MGT size to match customers’ needs. The investigation has been carried out using WTEMP code (Web-based ThermoEconomic Modular Program), developed by the Thermochemical Power Group of the University of Genoa [1][2][3]. The thermoeconomic analysis was performed on the basis of the thermodynamic, geometric and capital cost parameters of the main MGT devices (i.e. recuperator effectiveness, turbine inlet temperature, compressor pressure ratio, etc.) and on the economic scenario (fuel costs, cost of electricity, etc.). The subjects of the analysis were the existing Regenerative MGT (R-MGT) cycles [4][5] and new Inter-cooled Regenerative (ICR-MGT) cycles; for the sake of simplicity in this study, the economic value of heat in the case with CHP configuration was not considered.

Performances and Application Perspectives of Air Heat Recovery Turbine Units

2010 ◽  
Author(s):  
Vyacheslav V. Romanov ◽  
Sergey N. Movchan ◽  
Vladimir N. Chobenko ◽  
Oleg S. Kucherenko ◽  
Valeriy V. Kuznetsov ◽  
...  
Keyword(s):  
Power Output ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Exhaust Gas ◽  
Turbine Inlet Temperature ◽  
Compressor Pressure Ratio ◽  
Recovery System ◽  
Main Component

Adding an exhaust gas heat recovery system to a gas turbine (GT) increases its overall power output and efficiency. The introduction of an Air Heat Recovery Turbine Unit (AHRTU) using air as the heat-transfer agent is one of the ways of this increasing. This article presents the results of a GT with AHRTU for a turbine inlet temperature range from 573K to 873K and a compressor pressure ratio from 2.5 to 12. Main component performance of the AHRTU, weight and size are determined and optimized to match gas turbines. The potential for use of GT with AHRTU is specified. Exhaust gas heat recovery using a GT with AHRTU enable 4%–6% increases in efficiency (absolute), and 12%–20% increases in power output of mechanical drive plants.

scholarly journals New Diagram and Equation for Thermodynamic Calculations for Gas Turbines

1984 ◽  
Author(s):  
B. Herrmann
Keyword(s):  
Gas Turbines ◽  
Liquid Fuel ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Gas Temperature ◽  
Iso Standard ◽  
Compressor Pressure Ratio ◽  
German Standard ◽  
Exhaust Gas Temperature ◽  
Acceptance Tests

On basis of ISO-Standard 2314, the German Standard Organisation (DIN) has prepared the German Standard DIN 4341, which deals with acceptance tests for gas turbines. Sample calculations have been included. In connection with the development of the sample calculations a new diagram for thermodynamic properties of air and products of combustion was developed on basis of -humid air as per ISO standard 2314 -standard gaseous fuel -standard liquid fuel This diagram allows exact calculation of performance data. Further, a simplified but relatively acurate formula is presented for calculating the turbine inlet temperature on basis of -compressor pressure ratio -exhaust gas temperature -thermal efficiency Development and limitation of this formula is presented.

Thermodynamic and Energy Study of a Regenerator in Gas Turbine Cycle and Optimization of Performances

2016 ◽  
Vol 5 (2) ◽  
pp. 25-44
Author(s):  
Saria Abed ◽  
Taher Khir ◽  
Ammar Ben Brahim
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Parametric Study ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Compressor Pressure Ratio ◽  
Compressor Inlet ◽  
Gas Turbine Cycle

In this paper, thermodynamic study of simple and regenerative gas turbine cycles is exhibited. Firstly, thermodynamic models for both cycles are defined; thermal efficiencies of both cycles are determined, the overall heat transfer coefficient through the heat exchanger is calculated in order to determinate its performances and parametric study is carried out to investigate the effects of compressor inlet temperature, turbine inlet temperature and compressor pressure ratio on the parameters that measure cycles' performance. Subsequently, numerical optimization is established through EES software to determinate operating conditions. The results of parametric study have shown a significant impact of operating parameters on the performance of the cycle. According to this study, the regeneration technique improves the thermal efficiency by 10%. The studied regenerator has an important effectiveness (˜ 82%) which improves the heat transfer exchange; also a high compressor pressure ratio and an important combustion temperature can increase thermal efficiency.

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