A Thermo-Environmental Evaluation of a Modified Combustion Gas Turbine Plant

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Abdul Khaliq ◽  
M. A. Habib ◽  
Keshavendra Choudhary
Keyword(s):  
Relative Humidity ◽  
Gas Turbine ◽  
Air Cooling ◽  
Moderate Increase ◽  
Turbine Plant ◽  
Combustion Gas ◽  
Ambient Relative Humidity ◽  
Co Concentration ◽  
Gas Turbine Plant ◽  
Gas Turbine Cycle

This paper reports the comprehensive thermodynamic modeling of a modified combustion gas turbine plant where Brayton refrigeration cycle was employed for inlet air cooling along with evaporative after cooling. Exergetic evaluation was combined with the emission computation to ascertain the effects of operating variables like extraction pressure ratio, extracted mass rate, turbine inlet temperature (TIT), ambient relative humidity, and mass of injected water on the thermo-environmental performance of the gas turbine cycle. Investigation of the proposed gas turbine cycle revealed an exergetic output of 33%, compared to 29% for base case. Proposed modification in basic gas turbine shows a drastic reduction in cycle's exergy loss from 24% to 3% with a considerable decrease in the percentage of local irreversibility of the compressor from 5% to 3% along with a rise in combustion irreversibility from 19% to 21%. The environmental advantage of adding evaporative after cooling to gas turbine cycle along with inlet air cooling can be seen from the significant reduction of NOx from 40 g/kg of fuel to 1 × 10−9 g/kg of fuel with the moderate increase of CO concentration from 36 g/kg of fuel to 99 g/kg of fuel when the fuel–air equivalence ratio reduces from 1.0 to 0.3. Emission assessment further reveals that the increase in ambient relative humidity from 20% to 80% causes a considerable reduction in NOx concentration from 9.5 to 5.8 g/kg of fuel while showing a negligible raise in CO concentration from 4.4 to 5.0 g/kg of fuel.

Thermodynamic Study of Humid Air Gas Turbine Cycle Power Plants

2005 ◽  
Author(s):  
R. Yadav ◽  
P. Sreedhar Yadav
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Substantial Reduction ◽  
Thermodynamic Study ◽  
Humid Air ◽  
Turbine Plant ◽  
Design Engineers ◽  
Gas Turbine Plant ◽  
Gas Turbine Cycle

The major challenges before the design engineers of a gas turbine plant and its variants are the enhancement of power output, substantial reduction in NOx emission and improvement in plant thermal efficiency. There are various possibilities to achieve these objectives and humid air gas turbine cycle power plant is one of them. The present study deals with the thermodynamic study of humid air gas turbine cycle power plants based on first law. Using the modeling and governing equations, the parametric study has been carried out. The results obtained will be helpful in designing the humid air gas turbines, which are used as peaking units. The comparison of performance of humid air gas turbine cycle shows that it is superior to basic gas turbine cycle but inferior and more complex to steam injected cycle.

A Cost-Effective Indirect Coal-Fired Gas Turbine Power and Water-From-Air Cycle

1985 ◽  
Vol 107 (4) ◽  
pp. 861-869 ◽  
Author(s):  
P. R. Trumpler
Keyword(s):  
Gas Turbine ◽  
Cost Effective ◽  
Inlet Temperature ◽  
Turbine Plant ◽  
Air Heater ◽  
Gas Turbine Plant ◽  
The Cost ◽  
Gas Turbine Cycle ◽  
Steam Plant ◽  
Plant Capacity

An ideal open gas turbine cycle with multiple-stage intercooled compression and multiple-stage reheat expansion theoretically approaches Carnot thermal efficiency. A proposed practicable process to utilize this cycle with indirect firing of coal as fuel, with an air heater in place of the boiler, a turbine inlet temperature of 1700°F (927°C) and top pressure of 788 psia (53.6 atm) gives promise of lowering power plant station heat rates (HHV) from 8970 Btu/kWh currently realized by the best scrubber-equipped coal fired steam plants to 7460, a reduction of 16.8% in fuel consumption and consequently the cost of flue gas scrubbers. In addition, a 316 MW plant delivers at rated output 130,000 gal per day water stripped from atmospheric air. Primarily because of an expensive air heater and regenerator the gas turbine plant is penalized by an estimated increase in initial cost from $1000/kW for a steam plant to $1433/kW. With coal priced at $3/million Btu, water selling at 2¢/gal, money at 8% interest, inflation at 5%, and an 81% plant capacity factor, the payback period is 17 years.

The Optimum Pressure Ratio for a Combined Cycle Gas Turbine Plant

1995 ◽  
Vol 209 (4) ◽  
pp. 259-264 ◽  
Author(s):  
J H Horlock
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Maximum Efficiency ◽  
Specific Work ◽  
Optimum Pressure ◽  
Turbine Plant ◽  
Gas Turbine Plant ◽  
Overall Efficiency ◽  
Gas Turbine Cycle

A graphical method of calculating the performance of gas turbine cycles, developed by Hawthorne and Davis (1), is adapted to determine the pressure ratio of a combined cycle gas turbine (CCGT) plant which will give maximum overall efficiency. The results of this approximate analysis show that the optimum pressure ratio is less than that for maximum efficiency in the higher level (gas turbine) cycle but greater than that for maximum specific work in that cycle. Introduction of reheat into the higher cycle increases the pressure ratio required for maximum overall efficiency.

Combined Helium and Combustion Gas Turbine Plant Exploiting Liquid Hydrogen (LH2) Physical Exergy

1996 ◽  
Vol 118 (2) ◽  
pp. 257-264 ◽  
Author(s):  
G. Bisio ◽  
A. Massardo ◽  
A. Agazzani
Keyword(s):  
Gas Turbine ◽  
Exergy Analysis ◽  
Liquid Hydrogen ◽  
Combined System ◽  
Turbine Plant ◽  
Combustion Gas ◽  
Waste Gas ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Gas Turbine Plant

The aim of this work is the energy and exergy analysis of a combined plant made up of a conventional gas turbine (heavy-duty or aeroderivative) and a closed helium turbine cycle, which exploits liquid hydrogen (LH2) as a lower energy source. A helium turbine with the characteristics of the fluid allows us to operate between the usual temperatures of the top turbine waste gas and those of the liquid hydrogen available. In this way the combined system reaches efficiency values greater than every combined system proposed to date. The work contains a detailed analysis of the relative entropy productions of the helium cycle and considerations about the realization and technological aspects of helium turbines.

Thermodynamic Analysis of Air-Cooled Gas Turbine Plants

2000 ◽  
Vol 123 (2) ◽  
pp. 265-270 ◽  
Author(s):  
E. A. Khodak ◽  
G. A. Romakhova
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Direct Determination ◽  
Thermodynamic System ◽  
Flow Diagram ◽  
Air Cooling ◽  
Open Steam ◽  
Turbine Plant ◽  
Turbine Cooling ◽  
Gas Turbine Plant

At present high temperature, internally cooled gas turbines form the basis for the development of highly efficient plants for utility and industrial markets. Minimizing irreversibility of processes in all components of a gas turbine plant leads to greater plant efficiency. Turbine cooling, like all real processes, is an irreversible process and results in lost opportunity for producing work. Traditional tools based on the first and second laws of thermodynamics enable performance parameters of a plant to be evaluated, but they give no way of separating the losses due to cooling from the overall losses. This limitation arises from the fact that the two processes, expansion and cooling, go on simultaneously in the turbine. Part of the cooling losses are conventionally attributed to the turbine losses. This study was intended for the direct determination of lost work due to cooling. To this end, a cooled gas turbine plant has been treated as a work-producing thermodynamic system consisting of two systems that exchange heat with one another. The concepts of availability and exergy have been used in the analysis of such a system. The proposed approach is applicable to gas turbines with various types of cooling: open-air, closed-steam, and open-steam cooling. The open-air cooling technology has found the most wide application in current gas turbines. Using this type of cooling as an example, the potential of the developed method is shown. Losses and destructions of exergy in the conversion of the fuel exergy into work are illustrated by the exergy flow diagram.

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