scholarly journals Exergoeconomic and Environmental Modeling of Integrated Polygeneration Power Plant with Biomass-Based Syngas Supplemental Firing

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6018
Author(s):  
Fidelis. I. Abam ◽  
Ogheneruona E. Diemuodeke ◽  
Ekwe. B. Ekwe ◽  
Mohammed Alghassab ◽  
Olusegun D. Samuel ◽  
...  

There is a burden of adequate energy supply for meeting demand and reducing emission to avoid the average global temperature of above 2 °C of the pre-industrial era. Therefore, this study presents the exergoeconomic and environmental analysis of a proposed integrated multi-generation plant (IMP), with supplemental biomass-based syngas firing. An in-service gas turbine plant, fired by natural gas, was retrofitted with a gas turbine (GT), steam turbine (ST), organic Rankine cycle (ORC) for cooling and power production, a modified Kalina cycle (KC) for power production and cooling, and a vapour absorption system (VAB) for cooling. The overall network, energy efficiency, and exergy efficiency of the IMP were estimated at 183 MW, 61.50% and 44.22%, respectively. The specific emissions were estimated at 122.2, 0.222, and 3.0 × 10−7 kg/MWh for CO2, NOx, and CO, respectively. Similarly, the harmful fuel emission factor, and newly introduced sustainability indicators—exergo-thermal index (ETI) and exergetic utility exponent (EUE)—were obtained as 0.00067, 0.675, and 0.734, respectively. The LCC of $1.58 million was obtained, with a payback of 4 years, while the unit cost of energy was estimated at 0.0166 $/kWh. The exergoeconomic factor and the relative cost difference of the IMP were obtained as 50.37% and 162.38%, respectively. The optimum operating parameters obtained by a genetic algorithm gave the plant’s total cost rate of 125.83 $/hr and exergy efficiency of 39.50%. The proposed system had the potential to drive the current energy transition crisis caused by the COVID-19 pandemic shock in the energy sector.

2021 ◽  
Vol 11 (23) ◽  
pp. 11554
Author(s):  
Ali Baghernejad ◽  
Amjad Anvari-Moghaddam

Combined cycle systems have an important role in power generation. In the present study, three different configurations of combined Brayton and Rankine cycle system are studied from the perspective of energy, exergy, exergoeconomic and environmental perspectives. Results indicate that it depends on the preferences and criteria of each decision maker to select the best configuration among the three proposed configurations as the final configuration. For the purpose of parametric analysis, the effect of changing various parameters such as compressor pressure ratio, gas turbine inlet temperature on the output work, exergy efficiency, exergy-economic and environmental parameters is studied. In addition, an attempt is made to optimize the performance of combined cycle systems considering three objective functions of exergy efficiency, total cost rate and exergy unit cost of produced electricity.


Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 428 ◽  
Author(s):  
Wang ◽  
Fu

An integrated solar combined cycle (ISCC) with a low temperature waste heat recovery system is proposed in this paper. The combined system consists of a conventional natural gas combined cycle, organic Rankine cycle and solar fields. The performance of an organic Rankine cycle subsystem as well as the overall proposed ISCC system are analyzed using organic working fluids. Besides, parameters including the pump discharge pressure, exhaust gas temperature, thermal and exergy efficiencies, unit cost of exergy for product and annual CO2-savings were considered. Results indicate that Rc318 contributes the highest exhaust gas temperature of 71.2℃, while R113 showed the lowest exhaust gas temperature of 65.89 at 800 W/m2, in the proposed ISCC system. The overall plant thermal efficiency increases rapidly with solar radiation, while the exergy efficiency appears to have a downward trend. R227ea had both the largest thermal efficiency of 58.33% and exergy efficiency of 48.09% at 800W/m2. In addition, for the organic Rankine cycle, the exergy destructions of the evaporator, turbine and condenser decreased with increasing solar radiation. The evaporator contributed the largest exergy destruction followed by the turbine, condenser and pump. Besides, according to the economic analysis, R227ea had the lowest production cost of 19.3 $/GJ.


2019 ◽  
Vol 11 (12) ◽  
pp. 3264 ◽  
Author(s):  
S. M. Seyed Mahmoudi ◽  
Niloufar Sarabchi ◽  
Mortaza Yari ◽  
Marc A. Rosen

Comprehensive exergy and exergoeconomic assessments are reported for a proposed power producing system, in which an organic Rankine cycle is employed to utilize the waste heat from the fuel cell stack. A complete mathematical model is presented for simulating the system performance while considering water management in the fuel cell. The simulation is performed for individual components of the fuel cell system, e.g., the compressor and humidifiers. A parametric study is conducted to evaluate the effects on the system’s thermodynamic and economic performance of parameters, such as the fuel cell operating pressure, current density, and turbine back pressure. The results show that an increase in the fuel cell operating pressure leads to a higher exergy efficiency and exergoeconomic factor for the overall system. In addition, it is observed that the overall exergy efficiency is 4.16% higher than the corresponding value that is obtained for the standalone fuel cell for the same value of fuel cell operating pressure. Furthermore, the results indicate that the compressor and condenser exhibit the worst exergoeconomic performance and that the exergoeconomic factor, the capital cost rate and the exergy destruction cost rate for the overall system are 40.8%, 27.21 $/h, and 39.49 $/h, respectively.


2021 ◽  
Vol 1 (1) ◽  
pp. 15-24
Author(s):  
Malik El’Houyoun Ahamadi ◽  
Hery T. Rakotondramiarana

In the ylang-ylang essential oil distillers in Anjouan Island, the used energy is 100% firewood biomass. A large amount of this energy is dissipated in the environment just in the combustion chamber itself. As it turns out, the flue gases in this process take away the most part of it. Thus, in a process of energy efficiency of stills, the present work aims at assessing the possibility to convert the residual heat from the process into electricity. For that purpose, energy and exergy modeling of an organic Rankine cycle was implemented. It was found that a large amount of exergy is destroyed in the evaporator. Similarly, it emerges that the exergy efficiency of the cycle depends on the inlet temperatures of the exhaust gases in the evaporator and on the inlet pressure of the working fluid in the turbine, and that it is much better for low exhaust gas temperatures. At these low values of gas temperatures, it appears that the improvement in exergy efficiency and energy efficiency are linked to the increase in the inlet pressure of the working fluid in the turbine. It follows from the obtained results that the discharged hot water and the residual heat of gases having temperatures ranging from 180°C to 300 °C, could be used for power production which can reach electrical powers between 1.4kW and 4.5kW  


2021 ◽  
pp. 1-38
Author(s):  
Md. Tareq Chowdhury ◽  
Esmail M. A. Mokheimer

Abstract In this study, the performance of Parabolic Trough Collector (PTC) integrated with Organic Rankine Cycle (ORC) is investigated to find the optimum operating scenarios and to assess the exergy destruction at different components of the system. Commercial PTC LS-2 model with Therminol VP-1 as heat transfer fluid was integrated with an organic Rankine cycle that was examined for its thermal and exergetic performance using different organic fluids. It was found that every fluid has an optimum pressure and temperature level at which it works better than other fluids. R134a (Tetrafluoroethane, CH2FCF3) showed the best performance for the turbine inlet temperature range from 340 K — 440 K regarding the achieved energy and exergy efficiencies. At a temperature of 362.8 K and a pressure of 2750 kPa, R134a showed the highest energy efficiency of 8.55% and exergy efficiency of 21.84% with the lowest mass flow rate required in ORC. Energy efficiency of other fluids namely, R245fa (Pentafluoropropane, CF3CH2CHF2), n-pentane and Toluene were less than 5%. On the other hand, Toluene exhibited thermal efficiency of 23.5 % at turbine inlet temperature of 550 K and pressure of 2500 kPa, while the exergy efficiency was 62.89 % at solar irradiation of 1 kW/m2.


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