Polygeneration System Research Articles

Comprehensive energy, exergy, and economic analyses of a geothermal and flue gas-based dual-source power, hydrogen, and freshwater trigeneration system

Designing a ploy-generation system to produce various products is an effective method to improve the common power plant’s performance. Hence, the current investigation proposes a green poly-generation system driven by geothermal and flue gas. The proposed scheme consists of an organic Rankine cycle, proton exchange membrane electrolyzer, saline water desalination unit, and Allam cycle to produce power, hydrogen, and freshwater. The produced oxygen in the electrolyzer feeds the Allam cycle to perform an oxyfuel process to achieve zero CO2 emission. Per the 4E analysis, the system produces 27,720 kW net power, 931 kmol/h hydrogen, and 616.7 kmol/h freshwater. In this way, the energy and exergy efficiencies are obtained at about 16.87% and 51.65%. The total exergy destruction rate is estimated at about 78,926 kW, in which the organic Rankine cycle and its vapor generator have the highest portions among the different parts and equipment by about 69% and 18.87%. The sensitivity analysis indicates that by the CO2 recycle ratio of 60%, the highest energy and exergy efficiencies reach 19.3% and 54.33%. Furthermore, the unit cost of hydrogen and electricity productions are 0.07$/kWh and 7.24 $/GJ, which is a considerable reduction compared to similar methods.

Synergies between Carnot battery and power-to-methanol for hybrid energy storage and multi-energy generation

Power-to-methanol (PtMe) technologies and Carnot batteries are two promising approaches for large-scale energy storage. However, the current low efficiency and inadequate profitability of these two technologies, especially concerning green methanol production, pose challenges for their industrial implementation. One solution is to integrate these two technologies to augment the material and energy utilization efficiency through dynamic operational coordination and multi-energy production. This study systematically investigates the synergies of integrating CO2 energy storage (CES) and PtMe for combined heating, power, and methanol generation, aiming to enhance system's efficiency and economic viability. In this context, a novel hybrid energy-driven polygeneration system (CES-PtMe) is developed, featuring a highly integrated methanol production process and a newly proposed CES configuration with heating input and output capabilities. Detailed system simulations assess its performance under steady state, while nonlinear programming models are formulated for optimal storage sizing and energy scheduling considering fluctuating renewable energy. Various scenarios are set to examine the techno-economic potential of the CES-PtMe system, using renewable data from Gansu, China as a case study. The results indicate that the system can achieve a high efficiency of nearly 80% with a renewable penetration exceeding 77%. By incorporating optimal energy scheduling throughout the year, the system shows economic viability in the context of the current fossil energy market. While it has a limited ability to meet user energy demands, the proposed system retains economic benefits compared to standalone technologies.

A heat source self-supplied thermodynamic system using liquefied natural gas: Performance evaluation and three-objective optimization

In recent years, growing concerns have arisen due to the tight energy supply and escalating demand have driven the research on energy-efficient polygeneration systems. Liquefied natural gas (LNG) is highly regarded as a clean fossil fuel, capable of both cooling and serving as a heat source. This makes it a favored choice for thermodynamic system design. LNG gasification at −162 °C under standard pressure releases substantial cold energy. To avoid its waste, a novel self-supplying thermodynamic system was devised to recover this energy, incorporating a specific cold storage module that combines power generation and heating systems. This approach offers insights into creating polygeneration systems using LNG as the sole energy source. In light of the intricate energy exchanges within the system, based on the energy parameters of each stream, a comprehensive evaluation of its engineering feasibility is conducted through the analysis of energy, exergy, exergoeconomic, and exergoenvironmental parameters. Additionally, key parameters like R1150 mass flow rate, pump 3 outlet pressure, compressor 2 outlet pressure, LNG pump outlet pressure, and R23 liquefaction temperature are examined. Finally, the non-dominated sorting genetic algorithm II (NSGA-II), particle swarm optimization (PSO) and the multi-objective artificial hummingbird algorithm (MOAHA) rooted in hummingbird foraging behavior, are applied to optimize the proposed system. The results show that the energy utilization efficiency, exergy efficiency, product unit exergoeconomic cost, and product unit exergoenvironmental impact are 72.08%, 45.45%, 98.04 $/GJ, and 1.478 × 10−2 mpt/kJ, respectively. These excellent performance indicators demonstrate that the system is developable in the field of LNG utilization, filling a gap in the joint research of cold storage, power generation and heating for LNG cold energy utilization. Enhancing system performance can be achieved by increasing the mass flow rate of R1150 and the output pressure of compressor 2, reducing the output pressure of pump 3 and the liquefaction temperature of R23. When increasing the output pressure of LNG pump, can only increase exergy efficiency, while the energy utilization efficiency, product unit exergoeconomic cost and product unit exergoenvironmental impact all go down. Compared with the initial condition, after the application of MOAHA optimization, the exergy efficiency increased by 2.8%, the product unit exergoeconomic cost decreased by 3.47 $/GJ and the product unit exergoenvironmental impact decreased by 0.047 × 10−2 mpt/kJ. These results outperform those of NSGA-II and PSO, indicating that MOAHA can lead to superior system performance by overcoming multi-objective conflicts. This study provides valuable insights for designing and optimizing LNG cold energy utilization systems in situations without nearby heat sources or when power generation, heating, and cold storage are required.

Study on the Technical and Economic Viability of a Polygeneration Energy System Applied to a Hospital Unit in Bahia’s Countryside, Brazil

The present study aims to propose a polygeneration system model, integrating multiple forms of energy generation, such as photovoltaic systems, heat pumps, and other existing storage models to be used in a small-sized hospital unit in Bahia’s countryside. A polygeneration system was developed through a basic Project of the individual components and their integration as a unified system. The COP value, energy saving, and macro investment predictions were calculated, and financial indicators such as payback time, VPL, and TIR were determined. The results showed that the proposed system can supply the hospital’s energy demands and be considered a stimulating investment.

Design and Performance Assessment of a Novel Poly-generation System with Stable Production of Electricity, Hydrogen, and Hot Water: Energy and Exergy Analyses

Design and Performance Assessment of a Novel Poly-generation System with Stable Production of Electricity, Hydrogen, and Hot Water: Energy and Exergy Analyses

A novel power, DME, and ammonia polygeneration system using Aspen plus based on the integration of biomass gasification and syngas chemical looping

To solve the problems of fossil energy shortage and environmental pollution, a novel polygeneration system based on corn straw gasification was developed using Aspen Plus. The system consists of gasification, the supercritical CO2 cycle, syngas chemical looping, ammonia synthesis, methanol synthesis, and dimethyl ether (DME) synthesis subsystems. This system can simultaneously generate power, DME, and ammonia. Sensitivity, energy, and exergy analyses were conducted on the system. The results showed that the thermal and exergy efficiencies of the system are 60.15% and 46.70%, respectively. The system can recover the initial investment cost in 8 years, and within a 20-year life cycle, the net present value of this new solution can reach 1566.61 k$. The sustainability index (SI) value of the entire system is 1.88.

4E, risk, diagnosis, and availability evaluation for optimal design of a novel biomass-solar-wind driven polygeneration system

In this study, an innovative hybrid biomass-solar-wind driven polygeneration system has been presented. The presented system is integrated with two fuel cells and two electrolyzers. Also, considering the approach of using renewable systems, solar, and wind systems have been used in this system. The system integrated by two biomass fuels, olive pits and municipal solid waste (MSW), was examined for energy, exergy, exergoeconomic, and exergoenvironmental (4E) analysis and the results obtained from the 4E analysis of both fuels were compared with each other. The multigeneration system was examined from the point of view of risk and hazard of integrated systems, and the results showed that organic Rankine cycles (ORC) integrated into this system have high risk. Also, the system was evaluated by thermoeconomic diagnosis in terms of malfunction in the operation of the equipment. This evaluation indicates that solid oxide fuel cell (SOFC) performs well compared to other equipment. In addition, the results of this evaluation determined that the system in the functional state can consume fewer local resources than the reference state. Also, the proposed system was tested by assessing reliability and availability. In this analysis, while checking accessibility, the scenarios of increasing accessibility were discussed. Finally, considering this evaluation's effect, the system's cost and environmental impact were calculated. Finally, the polygeneration system was subjected to three-objective and four-objective optimization with the help of genetic and Lichtenberg algorithms. The objective functions selected for optimization are polygeneration efficiency, total cost rate, environmental impact rate, and risk.

6E evaluation of an innovative polygeneration system consisting of gas turbine cycle with CO2 capture, ejector refrigeration cycle, steam Rankine cycle, solar tower and MEDAD unit

The development of the energy systems in terms of technical performance and their assessment from an economic and environmental perspective has been a trending subject, lately. Due to global warming, the effectiveness of these systems has decreased. The pre-cooling technology of the incoming air is known as an influential factor to compensate for this limitation. In this study, we aim to provide a fossil fuel-based power generation system along with the solar energy, and upgrade it to a poly-generation system with the motivation to create an integrated set to meet the needs of power, cooling, heating, freshwater and CO2. In this framework, an integrated system consisting of gas turbine cycle (GTC) with CO2 capture, steam Rankine cycle (SRC), ejector refrigeration cycle (ERC), solar tower cycle (STC), hybrid multi-effect distillation adsorption desalination (MEDAD) is proposed, which presents a new design of a poly-generation system. The proposed system is modeled as a code in MATLAB to analyze energy, exergy, exergo-economic, exergo-environmental, emergo-economic and emergo-environmental (6E), and the validity of its thermodynamic results is compared with results obtained from simulation in Thermoflex. In addition, a parametric sensitivity analysis is performed that considers increasing the number of MEDAD stages, heating the air output from the air compressor (AC), pre-cooling the air entering AC to achieve the optimal operating conditions of the considered system in order to increase freshwater production, reduce fuel consumption and increase power generation. The results showed that the amount of freshwater produced with the correct use of thermal energy sources increases by 95.25 %, fuel consumption decreases by 22 % and net power of GTC increases by 5 %. Finally, the overall energy efficiency of the system in single generation (power production only) and multiple generation is 34.27 % and 65.65 %, respectively.

Techno-economic-environmental analysis and optimization of biomass-based SOFC poly-generation system

This study presents and investigates a biomass-based SOFC assisted carbon capture poly-generation system, which is integrated with the transcritical CO2 cycle, recompression supercritical CO2 Brayton cycle and double-effect LiBr absorption refrigeration cycle. In addition to supplying cooling, heating and power output, the proposed system can also provide the recovered condensate and the captured CO2. The techno-economic-environmental analysis and four-criteria optimization are performed to comprehensively investigate the system performance. The simulation results show that under the design condition, the overall efficiency, exergy efficiency and total cost rate of the system reach 93.00 %, 29.95 %, and 17.75 $/h. Parametric analysis reveals that the net power output reaches a maximum of 99.66 kW at the SOFC inlet temperature of 550 °C and the current density of 3680 A/m2. Besides, the four-criteria (the thermal efficiency, the exergy efficiency, the total cost rate and the life-cycle CO2 emissions) optimization results demonstrate that the exergy efficiency is increased by 3.19 % and the total cost rate is reduced by 21.18 % in the optimal condition compared with the base case. This work can provide references for the development and exploration of high-efficiency, low-emission, low-cost and multi-functional technologies for the biomass-based SOFC hybrid power system.

Defatted spent coffee grounds fast pyrolysis polygeneration system: Lipid extraction effect on energy yield and products characteristics

Spent coffee Grounds (SCG), residues after coffee brewing, are a biowaste diffused on a global scale rich of valuable extractives. Pyrolysis is an efficient process to valorize SCG energy content into biofuels. This study aims to experimentally investigate the impact of lipid extraction and conversion to biodiesel on energy yield of pyrolysis products. Microwave-assisted lipid extraction method was employed, and a two-step transesterification process was considered for conversion into biodiesel. Fast pyrolysis of defatted spent coffee grounds (DSCG) was performed with a 300 g/h screw reactor at the temperatures 400 °C and 550 °C. The results show an important impact of pyrolysis temperature on energy distribution of the pyrolysis products. The energy content of the organics from DSCG pyrolysis is very high (up to 32 MJ/kg) and the oxygen content is significatively reduced to 26%. Non-condensable gas composition is enriched of hydrogen and methane with temperature rise. Biodiesel energy contribution significantly improve the energy yield of the pyrolysis system, leading to a more than 10% increase of the energy efficiency at a 550 °C, while a limited increase of 4% in the case of 400 °C. This study outlines how lipids extraction significantly increases the economic potential of SCG pyrolysis-based polygeneration energy system.

Performance Assessment of a Novel Polygeneration System Based on the Integration of Waste Plasma Gasification, Tire Pyrolysis, Gas Turbine, Supercritical CO2 Cycle and Organic Rankine Cycle

Performance Assessment of a Novel Polygeneration System Based on the Integration of Waste Plasma Gasification, Tire Pyrolysis, Gas Turbine, Supercritical CO2 Cycle and Organic Rankine Cycle

Optimization under uncertainty of a hybrid waste tire and natural gas feedstock flexible polygeneration system using a decomposition algorithm

Market uncertainties motivate the development of flexible polygeneration systems that are able to adjust operating conditions to favor production of the most profitable product portfolio. However, this operational flexibility comes at the cost of higher capital expenditure. A scenario-based two-stage stochastic nonconvex Mixed-Integer Nonlinear Programming (MINLP) approach lends itself naturally to optimizing these trade-offs. This work studies the optimal design and operation under uncertainty of a hybrid feedstock flexible polygeneration system producing electricity, methanol, dimethyl ether, olefins or liquefied (synthetic) natural gas. A recently developed C++ based software framework (named GOSSIP) is used for modeling the optimization problem as well as its efficient solution using the Nonconvex Generalized Benders Decomposition (NGBD) algorithm. Two different cases are studied: The first uses estimates of the means and variances of the uncertain parameters from historical data, whereas the second assesses the impact of increased uncertain parameter volatility. The value of implementing flexible designs characterized by the value of the stochastic solution (VSS) is in the range of 260–405 M$ for a scale of approximately 893 MW of thermal input. Increased price volatility around the same mean results in higher expected net present value and VSS as operational flexibility allows for asymmetric exploitation of price peaks.

Techno-economic and life cycle assessment of the integration of bioenergy with carbon capture and storage in the polygeneration system (BECCS-PS) for producing green electricity and methanol

Bioenergy with carbon capture and storage (BECCS) has the potential to produce negative emissions. This study assessed the overall energy efficiency and carbon dioxide (CO2) avoidance costs and emission footprint following the integration of BECCS with a polygeneration system (BECCS-PS) for the co-production of green electricity and methanol. The process was simulated in Aspen Plus and Aspen HYSYS v.11. Oil palm empty fruit bunches were used as the feed in a biomass integrated gasification combined cycle power plant. The flue gas, which contained CO2, was captured for methanol synthesis and carbon storage. Green hydrogen for use in methanol synthesis was produced through proton exchange membrane (PEM) electrolysis powered by solar PV (PV-PEM) and geothermal power with double-flash technology (GEO-PEM). The environmental impacts of the process were investigated by a life cycle assessment and the economic aspects were evaluated using the levelized cost method. The overall system efficiency was higher in the PV-PEM scenario than in the GEO-PEM scenario. For any production capacities, the green electricity generated from the BECCS-PS plant resulted in negative emissions. A biomass power plant with a low production capacity generated higher production and CO2 avoidance costs than that with a larger production capacity. The CO2 − eq emissions and costs for methanol production in the PV-PEM scenario were larger than those in the GEO-PEM scenario, with values of -0.83 to -0.70 kg CO2 − eq/kg MeOH and 1,191–1,237 USD/ton, respectively. The corresponding values were − 1.65 to -1.52 kg CO2 − eq/kg MeOH and 918–961 USD/ton, respectively, for the GEO-PEM scenario.Graphical

Synergetic characteristic of a novel thermally-driven CCHP system based on supercritical and transcritical CO2 cycles

A novel poly-generation system is proposed based on supercritical carbon dioxide (SCO2) Brayton cycle and transcritical carbon dioxide (TCO2) refrigeration cycle to meet the seasonal energy demand in buildings. The thermodynamic model of the combined cooling, heating and power (CCHP) system was constructed based on the laws of thermodynamics, and seasonal operation modes were also analyzed. The Techno-economic performance of CCHP system was analyzed and compared with the single output systems and organic working fluids. The results show that the temperature of the turbine inlet in SCO2 cycle should be close to the heat source temperature and the temperature of the condenser outlet should be close to the critical temperature. The optimal pressure of the condenser outlet for coefficient of performance is about 9.3 MPa, while it is 8.6 MPa for power generation. The optimum thermodynamic and economic performance cannot be achieved simultaneously. The power generation of CO2 is 13.13% worse than that of organic working fluids and coefficient of performance of former is worse than that of latter. As the manufacturing cost goes down over time, the CCHP system based on CO2 will further improve its economic performance in the future.

Performance Evaluation of a Novel Multigeneration Plant of Cooling, Power, and Seawater Desalination Using Supercritical CO2 Partial Cooling, ME-TVC Desalination, and Absorption Refrigeration Cycles

Multigeneration systems have gained popularity and approval from scientific minds due to the enhancements these systems bring to total energy utilization efficiency. The use of waste heat from different thermodynamic cycles ensures deceleration of environment pollution. In this paper, a newly conceptualized poly-generation system combining power, cooling and desalination is proposed. Despite the high efficiency generated by the next generation supercritical CO2 (sCO2) Brayton cycles, the pre-coolers (cooling components) of the power block experience a substantial amount of low-grade energy loss. Utilizing this energy loss to increase thermal efficiency further has been the driving force behind this research. The proposed system has three subsystems which are sCO2 Partial cooling cycle with reheat for power generation, followed by a ME-TVC (multi-effect desalination-thermal vapor compression) cycle for producing fresh water and finally an absorption refrigeration cycle (ARC) to provide refrigeration effect. The waste heat from precoolers of sCO2 partial cooling cycle are being utilized by the desalination plant and refrigeration cycle for enhanced system performance. A comprehensive mathematical model is developed and a parametric assessment is performed. The parametric investigation focuses on the primary performance parameters, namely net power output, freshwater yield, energy utilization efficiency, coefficient of performance, and gain output ratio, to assess the multi-generation system's performance across various operational scenarios. The variables that are optimized are turbine inlet temperature of the sCO2 cycle, temperature difference of the generator and the evaporating temperature of the absorption cycle, the number and temperature of the effects of the desalination system. The results show that the greatest energy efficiency of the developed system is up to 70%. The 1st law energy efficiency is termed as Energy Utilization Factor (EUF) in the present work. This term adheres to the logic of the first law of thermodynamics by relating the total energy outputs to the system (work plus refrigeration capacity and heat supplied to the desalination plant) to the total energy input. Using the default parameters, the COP of the ARC is 0.667 and the EUF of the combined system is 59%. Both of these values are higher when compared to previous combined cycles found in literature.

Application of Circular Thermoeconomics to the Diagnosis of Energy Systems

This paper reviews the fundamentals of the thermoeconomic diagnosis theory. Thermoeconomic diagnosis is one of the main applications of the exergy cost theory used to identify the causes of additional resource consumption of a system due to inefficiencies in its components, published in the late 1990s. Thermoeconomic diagnosis has usually been applied to diagnose power plants with high consumption of fossil fuels and fixed production. However, it does not consider the final production and waste generation variation. In this paper, Circular Thermoeconomics is applied to analyze in depth the effect of malfunctions on additional waste generation and changes in the final output of the system. This new formulation can be applied to polygeneration systems, where there is a simultaneous variation of final products, and to process integration and industrial symbiosis, where a part of the waste generated by a plant could be reused in other processes or plants.

Techno-economic and environmental performance of a novel poly-generation system under different energy-supply scenarios and temperature and humidity independent control

The stand-alone energy production for power generation, heating or cooling is an usual method for low-medium grade energy utilization. To enhance the energy utilization efficiency, a combined cooling, heating, and power (CCHP) system, which is based on two-stage vapor compression cycle (TSVCC) and organic Rankine cycle (ORC), is proposed with temperature and humidity independent control (THIC). The essential parameters are changed to enhance the CCHP performances based on the thermodynamic model constructed. Moreover, the cooling performance are evaluated under different energy-supply scenarios, and the coupling effects of the CCHP are demonstrated through the THIC strategies. The results display that when the return air and fresh air are treated with energy of corresponding grade respectively, the higher outdoor relative humidity and the lower fresh air ratios are beneficial for enhancing refrigeration performance. The adverse effects of condensation temperature on both the economic and environmental performance far surpasses that of sub-cooling degree. With a rise of 10 °C in condensation temperature and sub-cooling degree, the economic performance decreases by 27.89% and 3.7% respectively, while the environmental performance decreases by 24.33% and 0.35% respectively. Furthermore, the proposed system can be switched to variant models according to different strategies in seasons to improve efficiency of energy utilization, which could be used in engineering applications.

Investigation of a novel near-zero emission poly-generation system based on biomass gasification and SOFC: A thermodynamic and exergoeconomic evaluation

SOFC poly-generation system exhibits the potential for clean and efficient conversion, but few studies have been conducted on the comparative analysis of the combined cooling, heating and power considering CO2 capture and condensate recovery. This study investigates a novel near-zero emission poly-generation system based on biomass gasification and SOFC employing different biomass fuels. This combined system adopting oxy-fuel combustion instead of traditional pre-combustion makes the flue gas easier to achieve a concentrated CO2 stream, thereby the system structure is simplified and the purity of captured CO2 is improved. The results reveal that the larch wood is the preferred fuel for the proposed system and the corresponding overall efficiency, exergy efficiency and unit cost of products achieve 80.17%, 29.12% and 20.49 $/GJ, respectively. The exergy analysis demonstrates that the exergy destruction mainly occurs in gasifier and turbine. The exergoeconomic analysis indicates that SOFC possesses a greater exergoeconomic factor of 85.12%. The parametric analysis shows that increasing gasifier temperature (Tgas), SOFC temperature difference (ΔT) and current density (j) decreases overall efficiency. The higher Tgas results in a higher unit cost (ct), whereas ct is more economic as ΔT increases. Besides, as j changing, ct of various biomass-based systems exists an optimal value.

Evaluation of an innovative polygeneration system based on integration of gasification process with a thermo electric generator- solid oxide fuel cell - Adsorption desalination system - Thermal photovoltaic collector

The current study is conducted to propose a polygeneration system for producing electricity, potable water, cooling, hot domestic water, hydrogen, oxygen, and nitrogen. The proposed system is fueled by heavy oil, natural gas, and solar radiation. Accordingly, the integration of an air separation unit, gasifier, gas turbine cycle, steam Rankine cycle, organic Rankine cycle combined by ejector refrigeration cycle, solid oxide fuel cell, thermoelectric generator, proton exchange membrane electrolysis, adsorption desalination, concentrated photovoltaic thermal collector and CO2 capture are done. The energy, exergy, exergoeconomic, exergoenvironmental, emergoeconomic, and emergoenvironmental analyses have been done to evaluate and compare different aspects of the system. With this, it becomes possible to move towards sustainable development by considering different aspects of the problem. For better performance of the system, multi-objective optimization was done using artificial intelligence. In this optimization, the decision variables were selected as a result of a comprehensive sensitivity analysis. As a result of this optimization the exergy efficiency of the system, LCOE, LEIOE, the emergy rate of the system, and the flow of produced hydrogen are 18.51%, 142.94$/MWh, 330.77Pts/MWh, 14443.28 × 1011 sej/s, 101.88 kg/h. The net power production of the system is 427.98 MW while the hydrogen cost is 19.56/GJ.

Development of an innovative high-performance poly-generation plant for efficient multi-level heat recovery of a biogas-powered micro gas turbine: Environmental and Multi-criteria analysis

Nowadays, the biogas-powered gas turbine cycles in poly-generation systems play a crucial role due to increasing fuel prices, declining renewable energy sources, and environmental concerns associated with fossil fuels. Concerning the high temperature of expanded gas, a novel high-performance poly-generation plant is achievable by intelligently selecting different subsystems. This paper presents a novel biogas-fueled poly-generation plant for producing electricity, refrigeration load, distilled water, and hydrogen simultaneously using multi-level heat recovery. An extended assessment of the devised plant output is performed based on energy-exergy, environmental, and exergoeconomic criteria, in which the plant’s gas turbine inlet temperature, preheated air temperature, air compressor pressure ratio, as well as turbine inlet pressure, are considered as variables. In the following, to demonstrate the advantages of using a Stirling engine, this study investigates two scenarios to reveal its superiority, and a bi-objective optimization is performed, where the objective functions comprise minimizing the poly-generation unit products cost and maximizing the sustainability index. When the plant is operated with a Stirling engine, the plant produces 986 kW of electricity, 137.5 kW of refrigeration load, 8.39 m3/h of distilled water, and 2.96 kg/h of hydrogen. In this case, the energetic and exergetic efficiencies of the proposed system are enhanced by 2.96% and 7.89%, respectively compared to non-Stirling engine mode. Also, the carbon dioxide emissions and sustainability index are ameliorated from 606.2 kg/MWh to 588.6 kg/MWh and from 1.47 to 1.5, respectively. In addition, the sensitivity analysis indicates that in a certain ratio of PRAC, the plant's performance reaches its optimal mode. Moreover, the unit cost of products and sustainability index are improved by 9.9% and 8%, respectively, compared to the base design case with the SE.