Exergoenvironomic modelling and performance assessment of selected gas turbine power plants

2016 ◽  
Vol 13 (2) ◽  
pp. 149-162
Author(s):  
Sunday Olayinka Oyedepo ◽  
Richard Olayiwola Fagbenle ◽  
Samuel Sunday Adefila ◽  
Md Mahbub Alam

Purpose This study aims to use an environomics method to assess the environmental impacts of selected gas turbine power plants in Nigeria. Design/methodology/approach In this study, exergoenvironomic analysis has been carried out to investigate the environmental impact of selected gas turbine power plants in Nigeria from an exergetic point of view. Findings The exergy analysis reveals that the combustion chamber is the most exergy destructive component compared to other cycle components. The exergy destruction of this component can be reduced by increasing gas turbine inlet temperature (GTIT). The results of the study show that thermodynamic inefficiency is responsible for the environmental impact associated with gas turbine components. The study further shows that CO2 emissions and cost of environmental impact decrease with increasing GTIT. Originality/value The exergo-environomic parameters computed in this study are CO2 emission in kg per MWh of electricity generated, depletion number, sustainability index, cost flow rate of environmental impacts (Ċenv) in $/h and total cost rates of products (ĊTot) in $/hr. For the period considered, the CO2 emissions for the selected plants vary from 100.18 to 408.78 kgCO2/MWhm, while cost flow rate of environmental impacts varies from $40.18 /h to $276.97 /h and the total cost rates of products vary from $2935.69/h to $12,232.84/h. The depletion number and sustainability index vary from 0.69 to 0.84 and 1.20 to 1.44, respectively.

2014 ◽  
Author(s):  
Richard Olayiwola Fagbenle ◽  
Sunday Sam Adefila ◽  
Sunday Oyedepo ◽  
Moradeyo Odunfa

Energy supply trends as well as environmental regulations and climate change issues have made it necessary to closely scrutinize the way energy is utilized. Efficient energy utilization thus requires paying more attention to accurate and advanced thermodynamic analysis of thermal systems. Hence, methods aimed at evaluating the performances of energy systems take into account the Energy, Environment and Economics. Therefore, the first and second law of thermodynamics combined with economics and environmental impact represents a very powerful tool for the systematic study and optimization of energy systems. In this study, a thermodynamic analysis of eleven selected gas turbine power plants in Nigeria was carried out using the first and second laws of thermodynamics, economic and environmental impact concepts. Exergetic, exergo-economic and exergo-environmental analyses were conducted using operating data obtained from the power plants to determine the exergy destruction and exergy efficiency of each major component of the gas turbine in each power plant. The exergy analysis confirmed that the combustion chamber is the most exergy destructive component compared to other cycle components as expected. The percentage exergy destruction in combustion chamber varied between 86.05 and 94.6%. Increasing the gas turbine inlet temperature (GTIT), the exergy destruction of this component can be reduced. Exergo-economic analysis showed that the cost of exergy destruction is high in the combustion chamber and by increasing the GTIT effectively decreases this cost. The exergy costing analysis revealed that the unit cost of electricity produced in the plants ranged from cents 1.88/kWh (₦2.99/kWh) to cents 5.65/kWh (₦8.98/kWh). Exergo-environmental analysis showed that the CO2 emissions varied between 100.18 to 408.78 kgCO2/MWh while cost rate of environmental impact varied from 40.18 $/h (N6, 388.62/h) to 276.97 $/h (N44, 038.23/h). The results further showed that CO2 emissions and cost of environmental impact decrease with increasing GTIT.


Author(s):  
Sepehr Sanaye ◽  
Younes Hamzeie ◽  
Mohammad Reza Malekian ◽  
Mohammad Reza Sohrabi

There is a rapid growth of electricity consumption in the world. This problem needs enough resources for capital investment for construction of new power plants and/or making all efforts to increase the thermal efficiency of existing power generation cycles. Therefore this situation has lead power generation industries to repower and modify the existing steam power plants which are constructed in the recent three or four decades. In this paper an important method for repowering of old steam power plants which uses a gas turbine is analyzed. Hot Wind Box (HWB) repowering method was technically and economically evaluated to repower the Besat steam power plant. This power plant was constructed and exploited in 1967 in Tehran. The optimum design parameters such as gas turbine power output, compressor and turbine isentropic efficiency, pressure ratio, and the ratio of turbine inlet temperature to compressor inlet temperature were found by defining an objective function the total cost per unit of repowered plant power output and using numerical search optimization technique for its minimizing. The objective function, the total cost, included initial or capital investment, operation and maintenance costs during plant life cycle. The numerical values of optimum design parameters and the results of the sensitivity analysis are reported.


Author(s):  
James Spelling ◽  
Björn Laumert ◽  
Torsten Fransson

A dynamic simulation model of a hybrid solar gas-turbine power plant has been developed, allowing determination of its thermodynamic and economic performance. In order to examine optimum gas-turbine designs for hybrid solar power plants, multi-objective thermoeconomic analysis has been performed, with two conflicting objectives: minimum levelized electricity costs and minimum specific CO2 emissions. Optimum cycle conditions: pressure-ratio, receiver temperature, turbine inlet temperature and flow rate, have been identified for a 15 MWe gas-turbine under different degrees of solarization. At moderate solar shares, the hybrid solar gas-turbine concept was shown to provide significant water and CO2 savings with only a minor increase in the levelized electricity cost.


2016 ◽  
Vol 106 (03) ◽  
pp. 136-140
Author(s):  
R. Miehe ◽  
M. Wiedenmann ◽  
T. Prof. Bauernhansl

Die Ökobilanz hat sich als Instrument zur Bewertung der Umweltauswirkungen von Produkten und Prozessen durchgesetzt. Dennoch stellt ihre Durchführung Nutzer immer wieder vor Herausforderungen. Der Fachartikel präsentiert einen Ansatz für eine vergleichende Betrachtung der ökologischen Auswirkungen des unternehmerischen Handelns auf Basis der jeweiligen Unternehmens- und Branchenumsätze. Der Umsatz-Nachhaltigkeitsindex soll als Konzept für ein Benchmark für Unternehmen einer Branche dienen.   Life Cycle Assessment has prevailed as an instrument to evaluate the environmental impact of products and processes. Its execution, however, poses a challenge to operators. In this paper, we present an approach for a comparative examination of environmental impacts of industrial behavior based on the turnover of companies and their equivalent sectors. The Turnover-Sustainability-Index serves as a benchmark for companies within a sector.


2018 ◽  
Vol 29 (1) ◽  
pp. 131-147 ◽  
Author(s):  
Eduardo Botti Abbade

Purpose The purpose of this paper is to investigate the associations between obesogenic severity, the public health situation, environmental impacts, and health care expenditures in populations worldwide. Design/methodology/approach This ecological study is based on official data available for approximately 140 countries worldwide. This study defines four main variables: obesogenic severity, environmental impact, public health implications (PHI), and health expenditures, all measured through specific indicators. Data were obtained mainly from the WHO, World Bank, and IDF. The indicators were reduced to the main variables through factorial reduction and multiple regression analyses were used to test the main hypotheses. Findings Obesogenic severity strongly and positively affects environmental impacts (β=0.6578; p<0.001), PHI-1 (cardiovascular risk factor) (β=0.3137; p<0.001) and PHI-2 (blood glucose and diabetes diagnoses) (β=0.3170; p<0.001). Additionally, environmental impacts strongly and positively affect PHI-1 (β=0.4978; p<0.001) but not PHI-2. Thus, results suggest that environmental impact, PHI-1, and PHI-2 strongly affect health expenditures (β=0.3154; p<0.001, β=0.5745; p<0.001, and β=−0.4843; p<0.001, respectively), with PHI-2 negatively affecting the health expenditures. Practical implications This study presents evidence that can aid in decision making regarding public and private efforts to better align budgets and resources as well as predict the needs and expenditures of public health care systems. Originality/value This investigation finds that the main variables addressed are strongly associated at the worldwide level. Thus, these analytical procedures can be used to predict public health and health care cost scenarios at the global level.


2013 ◽  
Vol 5 (5) ◽  
pp. 1243
Author(s):  
Clecia Simone Gonçalves Rosa Pacheco ◽  
Reinaldo Pacheco dos Santos

O presente artigo objetiva discutir e apresentar os resultados das análises feitas sobre a implantação de parques eólicos na região de Sento Sé/BA, seus impactos positivos para a matriz energética brasileira, a relevância do licenciamento ambiental visando evitar os impactos socioambientais negativos e as medidas de mitigação para combater tais impactos. Trata-se de uma pesquisa de natureza qualitativa e de caráter exploratório, e, para delineamento da mesma, utilizou-se de pesquisa bibliográfica para fundamentação teórica. No que diz respeito à coleta de dados, este se deu por meio das técnicas de observação in loco, e análise de discurso da população local. Mediante o que foi pesquisado é possível afirmar que é de fundamental importância a implementação de usinas de energia consideradas limpas e renováveis que possam contribuir para o desenvolvimento sustentável do país, sendo que o Brasil já foi apontado por um estudo do Programa das Nações Unidas para o Meio Ambiente como maior mercado mundial de energia renovável. No entanto, é importante enfatizar a necessidade de considerar as peculiaridades locais, principalmente as do Semiárido brasileiro e, efetivar um rigoroso Estudo de Impacto Ambiental (EIA) e seu consequente Relatório de Impacto Ambiental (RIMA) ao invés de Relatório Ambiental Simplificado (RAS). Palavras-chave: Energia eólica, Impactos Ambientais, Transformações Espaciais.  Parks Wind and Spatial Transformations: an Analysis of Environmental Impacts in the Region of Sento Sé/BA  ABSTRACT This article aims to discuss and present the results of analyzes made on the siting of wind farms in the region of Sento Se / BA, its positive impacts on the Brazilian energy matrix, the relevance of environmental licensing in order to avoid the negative social and environmental impacts and measures mitigation to address such impacts. This is a qualitative research and exploratory, and, for the same design was used for the theoretical literature. With regard to data collection, this was through the techniques of on-site observation and discourse analysis of the local population. By what has been researched is possible to affirm that it is of fundamental importance to the implementation of power plants considered clean and renewable that can contribute to sustainable development of the country, while Brazil has already been pointed out by a study of the United Nations Program for Environment as the largest global market for renewable energy. However, it is important to emphasize the need to consider local peculiarities, especially in the Semi and enforce a rigorous Environmental Impact Assessment (EIA) and subsequent Environmental Impact Report (RIMA) instead of Simplified Environmental Report (RAS).Keywords: Wind Energy, Environmental Impacts, Spatial Transformations. 


2015 ◽  
Vol 4 (5) ◽  
pp. 41-48 ◽  
Author(s):  
Кулаков ◽  
D. Kulakov ◽  
Щёголев ◽  
N. Shchegolev ◽  
Тумашев ◽  
...  

Coal mining is accompanied by the release of coal mine methane. Its emissions into the atmosphere within methane-air mixture have a negative impact on the ecological situation. The modern approach involves the use of methane-air-mixture for heat boilers or units to generate electricity. For the generation of heat and electrical energy the coal mine methane could be used in cogeneration gas turbine plants with an altered sequence of processes. Thermo — and gas dynamics studies were conducted in a wide range of parameters of gas turbine plants. For small power plants recommended are: 2.8 compression ratio, turbine inlet — 1173 K, gas cooler inlet temperature — 303 K, 0.8 regeneration ratio. In this case the electrical efficiency of gas turbine plant is 25–26% and even 63–64% if produced heat is counted. Cogeneration gas turbine plant with an altered sequence of process has smaller capital and operating costs compared to traditional gas turbine unit. The use of methane-air mixture as fuel in such gas turbine units increases the profitability of coal mining and improves the ecological situation in the region.


Author(s):  
G. Negri di Montenegro ◽  
M. Gambini ◽  
A. Peretto

This study is concerned with the repowering of existing steam power plants (SPP) by gas turbine (GT) units. The energy integration between SPP and GT is analyzed taking into particular account the employment of simple and complex cycle gas turbines. With regard to this, three different gas turbine has been considered: simple Brayton cycle, regenerative cycle and reheat cycle. Each of these cycles has been considered for feed water repowering of three different existing steam power plants. Moreover, the energy integration between the above plants has been analyzed taking into account three different assumptions for the SPP off-design conditions. In particular it has been established to keep the nominal value for steam turbine power output or for steam flow-rate at the steam turbine inlet or, finally, for steam flow-rate in the condenser. The numerical analysis has been carried out by the employment of numerical models regarding SPP and GT, developed by the authors. These models have been here properly connected to evaluate the performance of the repowered plants. The results of the investigation have revealed the interest of considering the use of complex cycle gas turbines, especially reheat cycles, for the feed water repowering of steam power plants. It should be taken into account that these energy advantages are determined by a repowering solution, i.e. feed water repowering which, although it is attractive for its simplicity, do not generally allows, with Brayton cycle, a better exploitation of the energy system integration in comparison with other repowering solutions. Besides these energy considerations, an analysis on the effects induced by repowering in the working parameters of existing components is also explained.


Author(s):  
W. J. Schulz ◽  
J. A. Mangiapane ◽  
H. Stargardter

The development of BORSIC®-Aluminum fan blades for elevated temperature application in gas-turbine power plants has been successfully demonstrated. These fan blades are over 40 percent lighter than the titanium blades currently in use. In addition, the high modulus of the reinforcement allows fan blades to be designed without partspan shrouds which will result in a 1 percent increase in fan efficiency. A full set of blades (36) fabricated by diffusion bonding were assembled in a rotor and tested in an aeromechanical rig with both a clean inlet and a distortion inlet at ambient inlet temperature as well as with a heated inlet to produce a blade temperature of 430 F. Total running time was 30.3 hrs, eight of which were at or above design speed. The rig ran for 0.5 hrs at design speed with a blade temperature of 430 F. No severe vibratory stresses were encountered with either a clean inlet or a 2E distortion screen.


Author(s):  
Mayank Maheshwari ◽  
Onkar Singh

Abstract Performance of gas/steam combined cycle power plants relies upon the performance exhibited by both gas based topping cycle and steam based bottoming cycle. Therefore, the measures for improving the performance of the gas turbine cycle and steam bottoming cycle eventually result in overall combined cycle performance enhancement. Gas turbine cooling medium affects the cooling efficacy. Amongst different parameters in the steam bottoming cycle, the deaerator parameter also plays its role in cycle performance. The present study analyzes the effect of deaerator’s operating pressure being varied from 1.6 bar to 2.2 bar in different configurations of simple and reheat gas/steam combined cycle with different cooling medium for fixed cycle pressure ratio of 40, turbine inlet temperature of 2000 K and ambient temperature of 303 K with varying ammonia mass fraction from 0.6 to 0.9. Analysis of the results obtained for different combined cycle configuration shows that for the simple gas turbine and reheat gas turbine-based configurations, the maximum work output of 643.78 kJ/kg of air and 730.87 kJ/kg of air respectively for ammonia mass fraction of 0.6, cycle efficiency of 54.55% and 53.14% respectively at ammonia mass fraction of 0.7 and second law efficiency of 59.71% and 57.95% respectively at ammonia mass fraction of 0.7 is obtained for the configuration having triple pressure HRVG with ammonia-water turbine at high pressure and intermediate pressure and steam turbine operating at deaerator pressure of 1.6 bar.


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