Integration of a Combined Cycle Power Plant with MED-RO Desalination Based on Conventional and Advanced Exergy, Exergoeconomic, and Exergoenvironmental Analyses

Evaluation of power and freshwater production based on integrated gas turbine, S-CO2, and ORC cycles with RO desalination unit

Exergy and exergoeconomic evaluation of hydrogen and distilled water production via combination of PEM electrolyzer, RO desalination unit and geothermal driven dual fluid ORC

Identification of behaviour and evaluation of performance of small scale, low-temperature Organic Rankine Cycle system coupled with a RO desalination unit

Experimental evaluation of a multi-skid reverse osmosis unit operating at fluctuating power input

Advanced exergy and exergoeconomic analysis for a polygeneration plant operating in geothermal cascade

Advanced exergy and advanced exergoeconomic analyses of biomass and natural gas fired combined cycles with hydrogen production

In this paper, freshwater production through multi-effect desalination (MED), multistage flash (MSF), reverse osmosis (RO), hybrid (MED-RO), and hybrid (MSF-RO) units have been investigated based on environmental impacts associated with life cycle assessment (LCA) modelling tool and exergoenvironmental analysis. The integration of Qom combined cycle as a real case study with selected desalination plants has been studied. In this regard, thermodynamic simulation has been performed in computer code with high accuracy. Furthermore, computer code has been developed to perform exergy, exergoeconomic, and exergoenvironmental analyses. Results show; the environmental impact rate associated with the integrated combined cycle with the MED unit decreased by 23% compared to the stand-alone power plant. Also, in the integration of combined cycle with MSF, RO, MED-RO, and MSF-RO, it has been found that 25%, 60%, 27%, and 25% decrease can be obtained in the environmental impact rates, respectively.

Advanced exergy and environmental analyses and multi objective optimization of a real combined cycle power plant with supplementary firing using evolutionary algorithm

In this paper, a small scale biomass gasification based solid oxide fuel cell/gas turbine (SOFC/GT) combined heat and power (CHP) plant is investigated by means of both conventional and advanced exergy and exergoeconomic analysis. A one-dimensional model of an internal reforming planner SOFC is employed to account for the temperature gradient within the fuel cell solid structure, which is maintained at the maximum allowable temperature gradient (150 K) under different operating conditions. Two main parameters of the gasification process, namely, air-to-steam ratio and modified equivalence ratio, are investigated, and the key parameters of the cycle exergy and exergoeconomic study are analyzed. Moreover, a multi-objective optimization procedure is applied to determine the unavoidable gasifier conditions required for the advanced exergy analysis of the system. The results of the conventional exergy and exergoeconomic analysis reveal that the highest rate of exergy destruction occurs in the gasifier, followed by the afterburner (AB) with 41.87% and 21.98%, respectively. Also, the lowest exergoeconomic factor is related to AB by 5.34%, followed by heat recovery steam generator (HRSG), gasifier, air compressor, and SOFC, which implies that the priority is to improve these components to reduce the exergy destruction cost rate. The results obtained from the advanced exergy and exergoeconomic analysis indicate that the most of the total exergy destruction rate is unavoidably in the CHP plant. The AB shows the least improvement potential in terms of reduction of the exergy destruction by almost 2% avoidable part, followed by Heat Exchanger 3 (H.X.3), gasifier, and SOFC duo to their lowest avoidable exergy destruction parts of almost 5%, 10% and 13%f respectively. Furthermore, the unavoidable part of the investment cost rate for all the components of the cogeneration plant is larger than the avoidable part, which means that it is difficult to reduce the investment cost rate of the system components. Meanwhile, the endogenous/exogenous analysis shows that the exergy destruction is completely endogenous for all components of the integrated plant, except for HRSG, GT, and HX1. Compressors and turbines have the highest potential to reduce endogenous exergy destruction. This is due to their higher avoidable endogenous exergy destruction. Reducing the investment cost rate seems difficult, as the main investment cost rate was found to be an unavoidable endogenous part for all system components. Finally, some results obtained from the advanced analysis approach are the opposite to those of the conventional method. This fact emphasizes that the results of conventional exergy analysis alone are insufficient and unreliable. For example, based on the advanced analysis perspective, the gas turbine and H.X.2 by 8.9% and 8.46% modified exergoeconomic factor, respectively, should be considered for reducing investment cost rate, while the conventional method gives opposite results.

Advanced exergy and exergo-economic analyses of an advanced adiabatic compressed air energy storage system

Biomass gasification for the production of clean energy and clean technology is a practical alternative to fossil fuels. In this paper, for the first time, a biomass Integrated Gasification Combined Cycle (IGCC) based on olive pits as fuel is investigated by conventional and advanced exergy, exergoeconomic and exergoenvironmental analyses (4E). Environmental impacts, availability, and interest in using olive pits as newly utilized renewable biomass sources have been considered in the present study. With conventional exergy analysis, the primary causes of entropy generation, exergy cost of destruction, and exergoenvironmental impacts in the plant can be indicated. Also, with advanced analysis, the real potential can be determined for improving the system as well as equipment interactions. The exerg environmental analysis has been performed based on Life Cycle Assessment and Eco indicator 99. In this regard, the LCA analysis based on Eco indicator 99 has been done by SIMA Pro software. Furthermore, computer code has been developed for thermodynamic simulation and conventional and advanced 4E analyses of the proposed system. It can predict the plant behavior for different operating conditions with relative errors of less than 2.5% with Thermoflex software. Results show the conventional and advanced 4E analyses and evaluation for considered biomass IGCC systems simultaneously. By the exergetic analysis, the location, values, and sources of entropy generation in the system are identified. By exergoeconomic analysis, the information about the cost in the components has been indicated in terms not only of capital investment but also of the cost of exergy. Through the exergoenvironmental analyses, it can be concluded that improving the efficiency and decreasing fossil fuel consumption are the key factors of promoting environmental characteristics. Splitting the exergy destruction, the capital investment cost, and the component-related environmental impact related to each component into endogenous/exogenous and avoidable/unavoidable parts promotes these analyses and enhances the quality of the conclusions achieved from them.

Advanced exergy and exergo-economic analyses of a novel combined power system using the cold energy of liquefied natural gas

In this paper, the superconducting carbon dioxide cycle is re-examined and compared from the perspective of advanced and thermoconomic exergy analysis to identify real potentials and prioritize the improvement of cycle components. In advanced exergy analysis, in addition to calculating the total exogenous exergy destruction for each component, the contribution and effect of each of the other components and their combination in causing this inefficiency have also been identified. In thermoeconomic analysis of the system, the unit cost of the product, the cost of investment and the cost of destroying the exergy for the components of the system are calculated. Improvements based on advanced exergy analysis are assigned to high temperature recuperator, turbine, compressor 1, preheater, low temperature recuperator, compressor 2 and reactor, respectively. Also, based on thermoeconomic analysis, improving the turbine and reactor is not economically justified. However, the results show that even by abandoning the improvement of these two components, due to their high economic cost and by improving other components of the cycle based on the prioritization of advanced exergy analysis, it is possible to increase the efficiency of the exergy cycle from 4/29/47. There is 63% to 47.4% and cycle energy efficiency from 34.15% to 45.84%.

Sensitivity analysis of exergy destruction in a real combined cycle power plant based on advanced exergy method

Conventional and advanced exergoeconomic assessments of a new air separation unit integrated with a carbon dioxide electrical power cycle and a liquefied natural gas regasification unit