Exergy Method Research Articles

Thermo-economic and environmental analyses of supercritical carbon dioxide Brayton cycle for high temperature gas-cooled reactor

The supercritical carbon dioxide (sCO2) Brayton cycle demonstrates special advantages for the high temperature gas-cooled reactor (HTGR) delivered into commercial operation recently in China, with its high efficiency, compactness, flexibility, and safety compared to the conventional steam Rankine cycle. However, the large temperature rise of 500 °C for the HTGR brings new challenges for the design of sCO2 cycle. Here, we present the first study on the thermodynamic, economic, and environmental performance of the HTGR-sCO2 system using the energy, exergy, economic, and environmental (4E) evaluation method. The cascaded sCO2 cycle made up of two independent sCO2 cycles is proposed, which are arranged in series on the cold side of reactor heat exchanger. We show that the cascaded sCO2 cycle can utilize the heat absorption from HTGR effectively by optimizing the cycle configurations of top and bottom sub-cycles. The improved cascaded sCO2 cycle minimizes the exergy loss, and increases the thermal efficiency to 43.2% when compared to the steam Rankine cycle of HTGR demonstration power plant and the single recompression cycle. By balancing the fixed-capital investment cost with the net power, the levelized cost of electricity can be reduced to 0.0283$/kWh. The life-cycle GHG emission intensity of HTGR-sCO2 systems is about 6.5gCO2,eq/kWh, which is much smaller than that of coal-fired power plants, suggesting a great potential for decarbonization of the HTGR-sCO2 system. Our study may find implications for the advancement of the sCO2 Brayton cycle in next-generation nuclear power plant.

Exergy analysis of hybrid air-conditioning systems with different evaporative-cooling condensers under hot-humid climates

Evaporative cooling (EC) technology can effectively improve the energy efficiency of the mechanical vapor compression (MVC) system by enhancing the heat exchange capacity of its condenser. However, the current evaporative-cooling condenser system is usually only equipped with a single-stage evaporative cooler as the precooling unit, and these designs are mainly suitable for hot-dry conditions. In this study, three hybrid air-conditioning systems with different two-stage evaporative-cooling condenser configurations were proposed, one is single-condenser type and the other two are dual-condenser type, which are used to improve the exergy performance and adaptability of the evaporative condenser system under hot-humid climates. Then, the all systems were modeled via the distributed parametric method and analyzed comparatively based on the exergy method. A suitable exergy reference temperature at air saturation was discussed. Finally, the effect of four key parameters (ambient temperature and relative humidity, outdoor airflow rate and room heat load) was studied. The results showed that under the high temperature, relative humidity or room heat load conditions, the hybrid systems have a low exergy efficiency ratio (EXR) and high exergy efficiency (ηx,OEC). Among them, the newly countercurrent dual-condenser configuration (MVC-TSEC(C)) exhibits the best exergy performance under most hot-humid conditions. Compared to the conventional MVC system, the EXR and ηx,OEC of MVC-TSEC(C) increased by at most 35.0 % and 78.2 %, respectively. Moreover, its components like compressor, condenser and expansion valve have the maximum reduction rates of exergy destruction of 43.5 %, 17.2 % and 55.3 %, respectively.

Thermodynamic analysis of a new tandem dual-temperature air source heat pump with ejector

This paper presents a conventional air source heat pump cycle (CHPC) and two dual-temperature air source heat pump cycles (DTHPC1 and DTHPC2). DTHPC1 employs two condensers, while DTHPC2 adds an extra compressor and combines the ejectors on top of DTHPC1. Compared with the conventional heat pump cycle, the new dual-temperature heat pump DTHPC2 can provide hot water at one additional temperature and still have high performance. In this paper, the refrigerants R1234yf and R1234ze(E) were selected as suitable for the cycle conditions. The cycle performance under different conditions was simulated and compared based on energy analysis methods and exergy analysis methods. The main performance parameters included COPh, ηex, etc. The results demonstrate that the COPh and ηex of DTHPC2 and DTHPC1 are greater than those of CHPC under identical conditions. Specifically, at an ambient temperature of approximately -10 °C, high-temperature hot water of approximately 65 °C, and low-temperature hot water of approximately 35 °C, the COPh of DTHPC2 and DTHPC1 increased by 45% and 32.7%, respectively, in comparison to CHPC. Similarly, the ηex of DTHPC2 and DTHPC1 increased by 27.1% and 28.9%, respectively.

Advancing Industrial Process Electrification and Heat Pump Integration with New Exergy Pinch Analysis Targeting Techniques

The process integration and electrification concept has significant potential to support the industrial transition to low- and net-zero-carbon process heating. This increasingly essential concept requires an expanded set of process analysis tools to fully comprehend the interplay of heat recovery and process electrification (e.g., heat pumping). In this paper, new Exergy Pinch Analysis tools and methods are proposed that can set lower bound work targets by acutely balancing process heat recovery and heat pumping. As part of the analysis, net energy and exergy load curves enable visualization of energy and exergy surpluses and deficits. As extensions to the grand composite curve in conventional Pinch Analysis, these curves enable examination of different pocket-cutting strategies, revealing their distinct impacts on heat, exergy, and work targets. Demonstrated via case studies on a spray dryer and an evaporator, the exergy analysis targets net shaft-work correctly. In the evaporator case study, the analysis points to the heat recovery pockets playing an essential role in reducing the work target by 25.7%. The findings offer substantial potential for improved industrial energy management, providing a robust framework for engineers to enhance industrial process and energy sustainability.

COMPARATIVE EXERGY ANALYSIS OF ADIABATIC AND ISOTHERMAL HUMIDIFICATION IN A DIRECT-FLOW CENTRAL AIR CONDITIONING SYSTEM

Central air conditioning systems of buildings and structures are significant consumers of electric and thermal energy of different temperature levels and are the least economical in terms of energy consumption. When designing these systems, due attention is not always paid to assessing their energy efficiency and no variant design is carried out with a comparison of the relevant indicators. This is due to the lack of proven engineering methods. The exergy method of analysing energy-consuming systems provides a correct numerical assessment of energy efficiency and enables a comparative analysis of circuit solutions and system elements. In contrast to the energy method, the peculiarity of the exergy method in relation to air conditioning systems is the possibility of taking into account all available mass and energy flows in the system in exergy units. The extension of the exergy method to systems for creating and maintaining a microclimate in buildings and structures has not yet acquired the status of practical engineering support. This article presents an example of an exergy analysis based on the original methodology for comparing methods of humidification in a central air conditioning system for a public building in order to select the best method in terms of energy efficiency. Two traditional methods of air humidification for the cold season - adiabatic and isothermal - were used for the study and comparison. The results of analytical studies are presented in the form of relative values of exergy.

Exergy-based method for evaluating the dynamic optimization of a supercritical water fluidized bed

Dynamic optimization of hydrogen production from coal gasification within an industrial-scale supercritical water fluidized bed is studied. Coal slurry and supercritical water mass flow rates are selected as the manipulated variables to investigate the optimal operation for scenarios involving variations in hydrogen demand. For the temperature-constrained scenario, supercritical water mass flow rate and temperature are manipulated. The results demonstrate that the optimal time-dependent profiles of the manipulated variables enable the supercritical water fluidized bed to meet variable demands of hydrogen and improve availability. Dynamic exergy methods are implemented to assess the thermodynamic behavior of different optimization schemes for efficient operation. The results show that more attention should be paid to the process of adjusting the mass flow rates of coal slurry and supercritical water simultaneously to vary the hydrogen yield because it requires the largest energy consumption. Manipulating the supercritical water mass flow rate causes less exergy destruction at a temperature constraint of 600 °C, but more exergy destruction at a temperature constraint of 700 °C.

Sensitivity and sustainability analysis of combined cycle plant with integrated LNG pressure energy recovery

Although combined cycle power plants (CCPPs) and liquefied natural gas (LNG) have arisen as solutions to the intermittent nature of renewable energy sources, they still need creative methods for performance enhancement and sustainability of the energy systems. Moreover, the energy efficiency of CCPPs is negatively impacted by environmental conditions, higher specific fuel consumption and a large quantity of waste heat released into the ambient. On the other hand, using seawater as a heating medium in LNG regasification circuits has a detrimental effect on the marine ecosystem. In this context, the LNG pressure energy recovery system through a direct expansion cycle (DEC) integrated with CCPP is proposed to improve sustainability, enhance exergetic performance and to reduce the heat recovery steam generator (HRSG) exhaust loss. To improve the cycle performance, low grade heat harnessed from CCPP is used as the heat source in the DEC rather than seawater. The system performance is analyzed by the energy and exergy method through a mathematical model. Moreover, the sensitivity analysis of the combined system is accomplished to examine the influence of LNG flow rate and ambient temperature on various performance indicators of the total system. It is observed that the integration of DEC boosts the HRSG performance by reducing the stack exergy loss and the efficiency is sensitive to LNG flow rate. The total integrated system energy efficiency ηtot, enhanced to 1.55% compared to the base case. Whereas, for ambient temperature in range of 15 – 45 °C, the system minimum and maximum exergetic efficiency ηex,tot is found to be 54.52 % and 55.94 %. Furthermore, the comparison of exergetic sustainability indicators is calculated and presented for three different simulation cases. The results demonstrate that increase in ηex,tot, affects the environment impact factor, ref and the sustainability index, θsi and improved 2.09 % compared to base case combined cycle.

Control-Volume-Based Exergy Method of Truncated Busemann Inlets in Off-Design Conditions

A scramjet engine consisting of several components is a highly coupled system that urgently needs a universal performance metric. Exergy is considered as a potential universal currency to assess the performance of scramjet engines. In this paper, a control-volume-based exergy method for the Reynolds-averaged Navier–Stokes solution of truncated and corrected Busemann inlets was proposed. An exergy postprocessing code was developed to achieve this method. Qualitative and quantitative analyses of exergies in the Busemann inlets were performed. A complete understanding of the evolution process of anergy and the location where anergy occurs in the inlet at various operation conditions was also obtained. The results show that the exergy destroyed in the Busemann inlet can be decomposed into shock wave anergy, viscous anergy and thermal anergy. Shock wave anergy accounts for less than 4% of the total exergy destroyed while thermal anergy and viscous anergy, in a roughly equivalent magnitude, contribute to almost all the remaining. The vast majority of inflow exergy is converted into boundary pressure work and thermal exergy. Some of the thermal exergy excluded by the computation of the total pressure recovery coefficient belongs to the available energy, as this partial energy will be further converted into useful work in combustion chambers.

Aerodynamic Exergy-Based Analysis and Optimization of the Generic Hypersonic Vehicle Using FUN3D

The development of future novel aircraft concepts requires a holistic approach to vehicle design, analysis, and optimization. Aircraft designers can no longer consider components individually as systems become more interconnected and multidisciplinary. Hence, a new approach to aircraft design and a new way to measure the performance of aircraft are needed. A novel approach to aircraft design is the use of exergy methods that can evaluate typically disparate systems using a universal measure of performance mapped to global system performance. This paper introduces a new functional and its adjoint gradient in FUN3D to determine aerodynamic exergy destruction rates. The functional is verified using the Oswatitsch relationship by comparing it to native, surface-based drag coefficients. The adjoint gradient is verified using the FUN3D native complex step method, and discrete agreement is demonstrated for flowfields and geometric derivatives. The new functional is then used for aerodynamic exergy-based analysis and optimization of the generic hypersonic vehicle. An inverse design problem is conducted first to verify the design optimization framework. Finally, a planform and airfoil aerodynamic inviscid exergy optimization of the GHV is conducted, improving exergy destruction rates by 7.1% while making substantial improvements to the cruise trim characteristics of the vehicle.

Performance analyses of basic cogeneration basic cogeneration plants in agriculture and food production

Energy in agriculture and in food production have vital importance that affect directly the cost and the quality of the products. Micro cogeneration plants are widely used in the World to produce heat and electricity at the same time in a same plant. The aim of this study, to analyze the performance of the production of power and heat for the food production process and the agricultural needs. For that reason, a basic cogeneration plant is taken to analyze the performance by using 1st and 2nd laws of thermodynamics and exergy analysis method. The electric-heat exergy rates, the energy and exergy efficiencies, the combustion chamber and the gas turbine outlet temperatures, the total electric and heat energies and exergies, and the specific works were calculated for various ambient temperatures and for various excess air rates of the basic cogeneration plants fueled with methane. The effects of the various ambient temperatures and the various excess air rates on the performance of the basic cogeneration plants were obtained, discussed and analyzed. For the best performance and for the best working conditions of the basic cogeneration plants in agriculture and food production process and food industry recommendations were done. It was found that, lower ambient temperatures give higher electric efficiency, but lower heat efficiency. However, an optimum excess air rates for the best performance was found at the value 2.3 of the excess air rates of the basic cogeneration plants fueled with methane.

Thermo-Economic Analysis and Multi-Objective Optimization of a Poly-Generation System Based on Solid Oxide Fuel Cell/Gas Turbine/Multi-Effect Distillation and Absorption Chiller Using Biogas as Fuel

A poly-generation system for cooling, heating, power, and fresh water is proposed, based on SOFC/GT/MED and an absorption chiller, with biogas as fuel. The performance of the system under the designed condition is analyzed using energy, exergy, and economic methods. An efficiency of 69.02% for comprehensive energy utilization and 35.56% for exergy are demonstrated by simulation results under the designed condition. A freshwater production of 469.93 kg/h is achieved, and a cost rate of 22.51 USD/h is incurred by the system. The effects of various parameters on the system characteristics are examined. Multi-objective optimization methods are employed to determine the final optimum operating condition that yields the best results in two schemes with different objectives. In comparison to the initial design, the optimization of the first scheme results in a 4.58% increase in the comprehensive energy utilization rate and a 2.02% increase in the exergy efficiency. However, the cost rate of the entire system increases by 0.63 USD/h. On the other hand, the optimization of the second scheme leads to a 19.51 kW decrease in the total energy output, a 276.38 kg/h increase in the freshwater production rate, and a 0.42 USD/h decrease in the cost rate of the entire system.

Exergy efficiency and EEXI analysis of a marine power plant at partial load conditions

Energy efficiency and environmental protection are becoming more important in the world. Almost 90% of the world trade is carried by sea which makes energy efficiency very important for the maritime sector. Exergetic method is a powerful scientific tool for measuring energy efficiency. The ships are not always cruising at maximum load conditions. The situations such as narrow water passages, maneuvering, and, hoteling etc. are partial load conditions and the exergy loss in power systems reaches maximum values at these conditions. Besides the new IMO regulation forces the sector to reduce emissions through Energy Efficiency Existing Ship Index (EEXI) and one of the most popular solutions is Engine Power Limitation (EPL). In the literature there are limited studies investigating exergy efficiencies of partial load conditions of a marine power plant. In this article, the performance analyses of a combined power system in partial load conditions are carried out using exergy method. The considered partial load conditions are maximum-ahead, full-ahead, half-ahead, slow-ahead and dead-slow-ahead loads of the engine. The results show that, the exergy efficiency of the overall system is decreasing at lower load conditions. It is observed that the maximum exergy efficiency is 51.6% which is reached at 96 rpm. The best condition considering both exergy efficiency and EEXI is 80 rpm of main engine. At slow-ahead and dead-slow-ahead conditions the exergy efficiency decreases to about 33%.

Advanced exergy analysis of a double absorption heat transformer recovering industrial waste heat for pure water production

Conventional and advanced exergy analyses are applied for a double absorption heat transformer system utilizing low-grade industrial waste heat for water purification. The conventional method provides information about the location and magnitude of inefficiencies and does not consider any interaction among components regarding the irreversibility occurring in them. The advanced exergy technique however, exposes the real origins of irreversibilities and latent potential for enhancement of each system component, along with reflecting mutual interaction between components. The simulation of the cycle is carried out with engineering equation solver software. The results show that the overall improvement potential of the cycle is only 16%. Also, the mutual interdependency between components is found to be weak as 97% of the total exergy destruction appeared as endogenous. Furthermore, considering endogenous avoidable exergy destruction, the improvement strategy of components obtained by advanced exergy method is disparate from conventional one. Results of the advanced exergy suggest this order: condenser, absorber, evaporator, absorber/evaporator assembly, generator assembly, economizer 1, and economizer 2. Additionally, a parametric investigation is performed to assess the sensitivity of splitting exergy destruction to the variation of heat source temperature for highlighting improvement opportunities. The results indicate that the condenser yields the highest amount of avoidable endogenous exergy destruction in the entire studied temperature range.

Barium Aluminates and the Study of their Basic Thermodynamic Data

The article presents the results of studies of thermodynamically stable barium aluminates. A database of thermodynamic data has been created: enthalpies, entropies and coefficients of the heat capacity equation, necessary for the study of multicomponent systems, including barium aluminates. Since the basis of modern materials science is multicomponent systems, on their basis it is possible to create various combinations of phases in structural materials with a set of specified properties. Thus, modern thermodynamics is not a frozen science. It is known that the objects of research are expanding, where thermodynamic methods can be applied to study the area of high and low temperatures, the area of very low and high pressures. And new discoveries give birth to new areas of application of thermodynamics: thermodynamics of thermonuclear reactions, plasma thermodynamics, relativistic thermodynamics, thermodynamics of negative absolute temperatures, etc. And, finally, the methods of thermodynamic research themselves do not remain unchanged: the exergy method, the methods of thermodynamics of irreversible processes, etc. At present, the thermodynamic method of research is widely used in various fields of physics, chemistry, biology, and many other sciences and branches of technology. Being one of the most extensive areas of modern natural science, thermodynamics plays an important role in the system of knowledge necessary for an engineer of any specialty in his practical activities. Chemical thermodynamics, on the other hand, paid the greatest attention to the study of phase transitions and the properties of solutions, and in relation to chemical reactions it was limited mainly to determining their thermal effects. To some extent, this is due to the fact that it was these areas of chemical thermodynamics that were the first to satisfy the needs of production. The practical use of known methods of thermodynamics of chemical reactions for solving major industrial problems for a long time lagged behind its capabilities.

RETRACTED: Analysis and optimization of thermal power plants: Pinch and exergy methods

The increasing demand for electrical energy and the depletion of fossil fuel reserves have underscored the need for the analysis and optimization of thermal power plants. This research focuses on the analysis and optimization of a combined cycle power plant that utilizes natural gas as its primary fuel. The study employs exergy analysis, pinch analysis, and related concepts to analyze the energy flows and identify inefficiencies within the system. The aims of the research are to determine the overall losses, component efficiencies, and overall efficiency of the combined cycle power plant and to optimize its performance using the atomic orbital search algorithm. The optimization aims to reduce waste and increase the overall efficiency of the power plant. By using these methods and algorithms, the research aims to address the challenges associated with fossil fuel consumption and contribute to the sustainable and efficient production of electrical energy. The overall exergy efficiency of the power plant increased from 68.73% in the design mode to 70.56% after optimization, resulting in a significant improvement in energy utilization and a reduction in exergy losses across the cycle components. In the low-pressure section of the heat recovery steam generator, exergy losses decreased from 2791.3 kW to 1600.67 kW after optimization, while in the high-pressure section, exergy losses reduced from 45,013 kW to 42509.72 kW. These optimizations demonstrate the potential to minimize exergy waste and enhance the overall performance of the power plant.

Process modeling and integration of hydrogen and synthetic natural gas production in a kraft pulp mill via black liquor gasification

The black liquor gasification integrated to chemical plants has shown potential for reducing the process irreversibility and promoting the decarbonization of this industrial sector. In the integrated chemical plants proposed in this work, the purpose is co-producing pulp and gaseous fuels, either hydrogen or synthetic natural gas, in order to expand the biorefinery product portfolio and, consequently, increase the plant revenues. However, due to additional equipment and utility demands, along with the uncertainty about the prices of the commodities; the benefits of the integrated setups must be thoroughly weighed by considering thermodynamic, economic and environmental indicators before the retrofit of the existing configuration is implemented. The exergy method is used along with the energy integration technique and other financial indicators to determine whether and in which scenarios the integrated biorefineries would be more attractive. The average exergy efficiency of the integrated chemical production plants is 44%, which is higher than that of the conventional case (40%). The balance of the overall CO2 emissions vary from 1.97 to −0.56 tCO2/tPulp, for the conventional and integrated setups, respectively. An incremental financial analysis under uncertainty also shows that the hydrogen production route with partial import of electricity and carbon taxations above 60 EUR/tCO2 outperforms the other scenarios. Therefore, the import of electricity from low-carbon grids and the upgrade of biorefinery residues arise as key factors for ensuring the sustainable production of traditionally fossil-based chemicals under more stringent environmental regulations.

Development and assessment of an offshore-based integrated hydrogen production and liquefaction system

The conventional hydrogen production methods depending on fossil fuels raise sustainability concerns. Therefore, there is a crucial need to develop sustainable and energetically self-sufficient hydrogen production processes. In this paper, an integrated hydrogen production and liquefaction system is developed to meet the hydrogen energy needs of communities. For this purpose, the present integrated system is considered and applied to the Hornsea Wind Farm, being developed off the east coast of the East Coast in the North Sea. The system aims to produce gaseous hydrogen by an electrolyzer and liquefy it by utilizing the energy input coming from a wind farm. The thermodynamic analysis is performed for the overall system and its components using energy and exergy methods through balance equations. Furthermore, the parametric evaluations are implemented to investigate the effects of varying operational conditions and design parameters on some key energy and exergy performance indicators. Under the specified conditions, the current study obtains the following results: an overall energy efficiency of 70.45 %, an overall exergy efficiency of 57.32 %, and a specific energy consumption of liquefaction plant (SEC) of 62.24 kWh/kg-LH2. Moreover, the levelized cost of H2 for the plant is found to be $7.28/kg. This research also reveals the primary sources of exergy losses by providing valuable insights to enhance the system's exergetic performance with some potential optimization opportunities. Furthermore, this study is expected to help achieve a more sustainable and decarbonized energy future with green hydrogen production and liquefaction for use.

Evaluating the dynamic heat efficiency of intermittent heating terminals using energy, exergy and entransy-based methods

Evaluating the dynamic heat efficiency of intermittent heating terminals using energy, exergy and entransy-based methods

INCREASING THE EFFICIENCY OF HEAT PUMP USING CIRCULATING WATER OF POWER PLANTS

In the article analytical studies of the efficiency of heat pumps in the thermal schemes of thermal and nuclear power plants for centralized heating and hot water supply systems taking into account the climatic conditions of Ukraine have been carried out. This task meets the objectives of energy saving and reduces emissions of harmful substances into the environment. The main focus is on improving the efficiency of the heat pump power supply system, which integrates an alternative energy source. An analysis of the exergy parameters of heat pump cycles has been performed, which have made it possible to establish that the most efficient working fluid of the cycle is freon R152a, at which the highest heat pump conversion coefficient and the lowest compressor power indicator are achieved. Ways and methods leading to reduction to underproduction of the electricity by turbine of of power plant and to increasation of the efficiency of a steam turbine cycle are proposed. It is shown that the efficiency of the system is most affected by losses in the evaporator, so the efficiency of this element of the heat pump should be given the most attention when using the energy of circulating water. An additional aspect of the novelty of the proposed method lies in the possibility of further optimization of the technical and economic parameters of the power system. A methodology based on the use of the exergy method of analysis to substantiate the conditions for the rational use of heat pumps for power plants in the utilization of low-grade heat of circulating water for cooling the turbine condensers is proposed, which can be considered as innovative way. Results open the further prospects for the development of heat pump heat supplyhas been proposed.

A strategy for CO2 capture and utilization towards methanol production at industrial scale: An integrated highly efficient process based on multi-criteria assessment

CO2 capture and utilization are an effective solution to the problem of CO2 emissions, and a combination of ammonia-based CO2 capture and its use for methanol production is a highly feasible strategy. However, the uses of conventional technologies have resulted in a high demand for energy, with limited use of hydrogen. To address these problems, an innovative strategy is proposed and demonstrated in this study that enhances the conventional design, i.e., to use ammonia-based CO2 capture with double tower absorption and solvent split, along with wet hydrogen for methanol production at industrial scale. The process is further improved through a multi-criteria assessment that considered the CO2 capture rate, NH3 loss rate, CO2 conversion rate, and energy saving factors, in which the latter is based on two components, namely the reboiler duty and the condenser duty. Moreover, an exergy analysis method is used to optimize the improved process, and a highly efficient integrated process is finally established. It has been found that the use of a double-tower absorption process ensures high rates of CO2 capture and low rates of NH3 loss. Additionally, adjusting the molar ratio of H2 to CO2 leads to an impressive 8% increase in the CO2 conversion rate, reaching 25%. In terms of energy savings, the average reboiler duty was reduced from 13.39 to 11.85 MJ/kgCO2, i.e., by 11.50%; while the condenser duty was reduced by 11.36%; both contributed to the overall energy savings. In the I-ACCMP process, the total exergy loss is 437.24 kW, of which the exergy loss of the heat exchangers accounts for 16%, and the desorption tower (DES) accounts for 48%. After optimization, the exergy loss of the heat exchangers decreases from 70.02 kW to 40.45 kW, the exergy loss of the DES decreases from 209.29 kW to 180.91 kW, and the reboiler duty is reduced from 10.60 MJ/kgCO2 to 7.71 MJ/kgCO2. The total exergy loss decreases from 437.24 kW to 372.68 kW, which is a reduction by 14.8%.