Search

This study presents a novel multi-generation system (MGS) assisted by sugarcane bagasse to produce power, freshwater, and cooling. The proposed integrated MGS consisted of a bagasse-biomass based gasifier-Brayton cycle, a Rankine cycle, a Kalina cycle, an ejector refrigeration cycle, and a multi-effect desalination unit. Comprehensive energy, economic, exergy, exergorisk (4E) analyses of the proposed system were performed. The effects of operating parameters on thermodynamic performance and economic feasibility were investigated. An optimal configuration of the proposed system was determined via weighted multi-objective optimization approach considering exergorisk, exergy, and economic analyses. The results showed that bagasse-biomass flowrate was the dominant factor affecting variation in energy and exergy efficiencies, and total cost rate. An increase in bagasse-biomass flowrate from 1.5 kg/s to 10 kg/s led to decreases of 34.42% and 50.75% in overall energy and exergy efficiencies. The most substantial increase (43.07%) in exergy efficiency occurred at a high compression ratio. The optimization results showed that the total accidental risk impact was improved by 92.59% and energetic and exergetic efficiency was increased to 92.10% and 77.49%, respectively. The proposed optimum system can provide power, cooling, and freshwater at loads of 28.72 MW, 13.64 kg/s, and 3.43 MW, respectively. Image 1 • Bagasse gasification based novel sustainable multi-generation system is proposed. • Investigating sensitivity of system performance and costs to the key parameters. • The system is optimized decreasing total cost rate and exergorsik analysis. • Optimized system has high energetic and exergetic efficiency (92.1% and 77.49%). • Bagasse biomass contribution leads to higher power generation. [ABSTRACT FROM AUTHOR]

• A novel steam jet ejector power plant was proposed to adapt to climate change. • A new genetic algorithm solved the multi-objective optimization model. • Two wet cold utilities were evaluated via four new water-exergy nexus criteria. • The novel system loses 63.65% less water than available steam power plants. • The thermal efficiency of the proposed eco-friendly system reached 40.59%. Steam power plants contribute to anthropogenic climate change by emitting a considerable amount of carbon dioxide and losing significant freshwater. In the present study, a novel model-based steam jet ejector power plant is optimally designed to adapt to climate change by minimizing water losses and greenhouse emissions. An iterative thermo-mathematical program and a nonlinear mathematical model represent the system's energy and economic models. At the same time, an exergy analysis evaluates its performance according to the Second law of thermodynamics. A non-dominated sorting genetic algorithm generation III is interfaced with the developed empirical program to solve a multi-objective optimization model. Three decision-making scenarios including a maximum thermal efficiency (I), minimum cost of energy (II), and minimum heat losses (III) are considered to select appropriate configurations in the final Pareto front. Subsequently, a natural draft wet cooling tower and a once-through cooling system are coupled with the optimal configurations. The performance of the fully-integrated systems is evaluated using four new water-exergy nexus criteria including water withdrawal for exergy dissipation, lost exergy for exergy dissipation, water consumption for fuel and product exergies. Finally, a sensitivity analysis is performed to take the environmental fluctuations and model uncertainties into account. The comparative results showed that water consumption for product and fuel exergies improved by 63.65 and 64.08%, while water withdrawal for exergy dissipation of the system was approximately nine times smaller than available model-based steam power plants. Moreover, the energy efficiency of the proposed system was 1.42% greater than the previous systems at the cost of 0.018 $/MJ more cost of energy. Thus, the proposed system can tackle drought and mitigate climate change with more investment in the energy sector. [ABSTRACT FROM AUTHOR]

• A chemical exergy pinch analysis is proposed via optimal pressure retarded osmosis. • The graphical tool is detailed using grand composite curves. • The numerical tool is detailed using cascade tables under three scenarios. • The high exergetic potential of 1384.7 MW is diagnosed in the sugar mill. • The PRO module could commercially recover 11.3 MW waste energy with 0.038 $/kWh. In the present study, pinch analysis is extended taking chemical exergy concept into account. The novel chemical exergy pinch analysis is proposed for sustainable power production by an economic application of pressure retarded osmosis membranes in chemical industries. Chemical exergy composite curves and chemical exergy cascade tables are developed as graphical and numerical tools, respectively. The tools are used to obtain maximum waste energy recovery by achieving various targets and determining the pinch point in a salinity gradient network. Thus, maximum energy recovery and minimum waste treatment are targeted, simultaneously. Moreover, a mathematical model follows the chemical exergy pinch analysis for an economic evaluation of pressure retarded osmosis-retrofitted industries under three probable scenarios. A sugar mill plant is simulated as the case study to validate the model-based analysis. The results showed that chemical exergy pinch analysis could efficiently provide the optimal pressure retarded osmosis -retrofitted industrial networks for decision-making. Having analysed the complex chemical exergy streams by chemical exergy pinch analysis, 11.30 MW net power is recovered with 0.038 $/kWh levelized cost of energy in the case study. [ABSTRACT FROM AUTHOR]

• A comprehensive analysis for evaluating energy conversion systems is described. • A novel water-exergy nexus analysis is employed to evaluate hot and cold utilities. • A mathematical program is developed to model two integrated energy systems. • According to 4ER, power generation was preferred to power/cooling cogeneration. • Allocating steam caused less risks and costs but great water losses in cold utility. A holistic analytical approach is proposed to study the performance of fossil fuel burning integrated energy conversion systems considering energetic, economic, exergetic, environmental and risk (4ER) aspects in a framework. For this, life cycle assessment is conducted to study environmental impacts while other analyses are performed using the algebraic thermo-mathematical programming. The hazardous risks are also investigated using a hazard and operability approach. The external hot and cold utilities are also studied using a novel water-exergy nexus (WExN) analysis. Accordingly, two configurations are developed that integrate a Rankine cycle (RC) and an ejector refrigeration cycle (ERC) for two purposes: power and cooling co-generation (CGS) and power generation (MGS). Water losses in both systems are studied considering three cold utilities and two fossil fuel cycles using the WExN analysis, and the performance of the CGS and the MGS are compared employing several organic fluids. The results showed that the MGS had greater energetic and exergetic efficiencies, better environmental performance, and less hazardous risk impacts compared to the CGS employing almost all working fluids. The smallest exergy loss in the cooling system was 3.90 MW and 7.94 MW in the MGS allocating R123 and the CGS using R718, respectively. [ABSTRACT FROM AUTHOR]