Optimal Economic Performance Research Articles

Circular business activities and economic performance optimization in EU countries: towards consumption footprint management

Circular business activities and economic performance optimization in EU countries: towards consumption footprint management

Optimal IOFL-based economic model predictive control technique for boiler-turbine system

The optimal control design of the boiler-turbine system is vital to ensure feasibility and high responsiveness over desired load variations. Using the traditional linear control techniques realization of this task is difficult, as the boiler-turbine mechanism has strong nonlinearities. Besides, environmental and economic concerns have replaced existing tracking control ones as the primary concerns of advanced power plants. Thus, this study proposes an optimal economic model predictive controller (EMPC) scheme for this unit on the basis of the input/output feedback linearization (IOFL) method. By employing the IOFL method, this unit is decoupled into a new linearized model that is utilized for developing the suggested optimal IOFL EMPC technique. The proposed control scheme is formulated in an economic quadratic programming form that considers the input-rate and input limits of the unit for optimal economic performance. In addition, an adaptive iterative algorithm is utilized for constraints mapping with guaranteeing a feasible solution in a finite number of steps without violation of original constraints over the entire predictive horizon. The outcomes of the simulation show that the suggested optimal IOFL EMPC scheme offers an improved dynamic and economic output performance over fuzzy hierarchical MPC, fuzzy EMPC, and nonlinear EMPC techniques during various load variations.

Comparative analysis of solar module configuration and tracking systems for enhanced energy generation in South Sakucia Union, Bhola, Bangladesh: A software based analysis

Bangladesh is blessed with an extensive range of solar energy generation possibilities; however, the primary impediment to attaining its full potential in the solar energy industry is the inadequate budget in the energy sector. As a result, determining the most economical and efficient solar module configuration for each specific scenario has become a critical necessity. This study offers a comprehensive techno-economic analysis and environmental impact assessment of four distinct solar modules: monofacial, bifacial, dual-axis solar tracker, and seasonal tilt solar module, in an open area of South Sakucia Union, Bhola district, in the southwest part of Bangladesh. By integrating energy-generation capabilities, financial metrics, and environmental benefits, this research provides a holistic evaluation framework to ensure optimal economic performance and minimal adverse environmental effects for sustainable solar solutions in Bangladesh. Utilizing PV*SOL, PVsyst, and System Advisor Model (SAM) software, this study assesses energy-generation capabilities and economic viability. Despite the dual-axis solar tracker exhibiting the highest average energy generation (149,070.3 kWh/year), its higher initial cost renders it less financially viable compared to other configurations. Financial metrics reveal that the seasonal tilt configuration is the most cost-efficient, with the lowest Levelized Cost of Electricity (LCOE) at $0.0452/kWh and the highest Net Present Value (NPV) of $52,887.70. Additionally, it has the shortest Discounted Payback Period (DPBP) at 12.69 years, a favorable Internal Rate of Return (IRR) of 9.460 %, and a Profitability Index (PI) of 1.459, indicating robust returns on investment. These findings emphasize the importance of considering both energy-generation capabilities and financial metrics when evaluating solar module configurations in the southern part of Bangladesh, serving as a valuable reference for policymakers. Moreover, meticulous environmental impact assessments assist in choosing configurations with minimal adverse effects on the environment.

Multi-criteria study and optimization of an innovative combined scheme utilizing compressed air energy storage for a modified solid oxide fuel cell-driven gas turbine power plant fueled by biomass feedstock

This paper explores the potential of a combined solid oxide fuel cell and gas turbine technology for medium- to large-scale power generation, emphasizing its applicability and sustainability, particularly with biomass feedstock. An innovative heat integration process is developed for a modified solid oxide fuel cell and gas turbine power plant, incorporating a steam power cycle, compressed air energy storage, a Kalina cycle, and a domestic hot water production subsystem. The system utilizes biomass through a downdraft gasifier, enabling a comprehensive evaluation of thermodynamic, economic, and environmental performance during both charging and discharging phases. A detailed parametric sensitivity analysis is performed to investigate two operational modes. Subsequently, five multi-objective optimization scenarios are formulated and optimized using the cuckoo search algorithm and two decision-making approaches. The results indicate that the optimization scenario focusing on exergetic round-trip efficiency and the unit cost of products during the discharging phase achieves superior thermodynamic and environmental performance. Specifically, the system exhibits energetic and exergetic round-trip efficiencies of 59.20 % and 51.06 %, respectively, with a levelized total emission of 0.64 kg/MWh. Furthermore, when considering the objectives of exergetic round-trip efficiency and net present value, the optimal economic performance is achieved with a payback period of 1.54 years and a net present value of $7.44 million.

Experimental analysis of freezing desalination using gravity and centrifugal methods with economic evaluation of coupled freezing desalination and ice storage system

This study conducted experiments to compare the desalination efficiency of gravity and centrifugal desalination methods for freezing desalination, showing the superiority of centrifugal desalination. Moreover, through experiments on supercooled water production, it was determined that supercooled water can operate stably at an evaporator temperature of −4.5 °C, and its supercooling state can be released using ultrasound. Based on the experimental results, a novel system that combines freezing desalination with ice storage is proposed. The proposed system utilizes supercooled water for ice production and centrifugal post-treatment, using desalinated ice as a cold storage medium to integrate desalination and ice storage. The proposed system showed a 30 % lower total capital cost compared to conventional systems, with a payback period of 38.18 % lower than conventional system (5.42 years). Additionally, the system demonstrated optimal economic performance when utilizing 80 % of its ice storage capacity, with a payback period of 3.38 years, contrasting with 7.62 years when utilizing 20 % storage capacity. The application of this system in four regions with varying peak and off-peak electricity prices, including Guangdong, Fujian, Hainan, and, France revealed that the system demonstrates greater economic viability in areas with significant disparities in electricity pricing.

A Study on the Promoting Role of Renewable Hydrogen in the Transformation of Petroleum Refining Pathways

The refining industry is shifting from decarbonization to hydrogenation for processing heavy fractions to reduce pollution and improve efficiency. However, the carbon footprint of hydrogen production presents significant environmental challenges. This study couples refinery linear programming models with life cycle assessment to evaluate, from a long-term perspective, the role of low-carbon hydrogen in promoting sustainable and profitable hydrogenation refining practices. Eight hydrogen-production pathways were examined, including those based on fossil fuels and renewable energy, providing hydrogen for three representative refineries adopting hydrogenation, decarbonization, and co-processing routes. Learning curves were used to predict future hydrogen cost trends. Currently, hydrogenation refineries using fossil fuels benefit from significant cost advantages in hydrogen production, demonstrating optimal economic performance. However, in the long term, with increasing carbon taxes, hydrogenation routes will be affected by the high carbon emissions associated with fossil-based hydrogen, losing economic advantages compared to decarbonization pathways. With increasing installed capacity and technological advancements, low-carbon hydrogen is anticipated to reach cost parity with fossil-based hydrogen before 2060. Coupling renewable hydrogen is expected to yield the most significant economic advantages for hydrogenation refineries in the long term. Renewable hydrogen drives the transition of refining processing routes from a decarbonization-oriented approach to a hydrogenation-oriented paradigm, resulting in cleaner refining processes and enhanced competitiveness under emission-reduction pressures.

Energy and economic performance optimization of a window with variable transparency shape-stabilized PCM in hot summer and cold winter climate zone

Improving the thermal performance of windows is important for building energy efficiency. Filling windows with variable transparency shape-stabilized phase change materials (VTSS-PCM) improves the thermal inertia of windows while avoiding the leakage of PCM. In this paper, a new type of VTSS-PCM window was proposed, tested, simulated and optimized in hot summer and cold winter climate zone. A numerical model of the VTSS-PCM window was built, and the model was validated using experimental tests. On this basis, three key parameters of VTSS-PCM were investigated and optimized. Finally, the energy and economic performance of the optimized VTSS-PCM window were compared with a typical hollow glass window. The results showed that the total annual unfavourable heat transfer (TAHT) and the annual investment cost (AIC) of the VTSS-PCM window obtained from the optimization were 118.16 kWh/m2 and 8.53 CNY/m2, respectively. Compared with the hollow glass window, the VTSS-PCM window reduced the TAHT by 30.14% and the total annual cost by 28.39%. The VTSS-PCM window produced a better development potential in terms of energy performance and economic performance. This study provided a reference for the application of the VTSS-PCM window in hot summer and cold winter regions of China.

Operational decisions of photovoltaic closed-loop supply chains with industrial distributed photovoltaic subsidy policy in China

Photovoltaic (PV) generation, as a clean and renewable energy technology, aligns with the global needs for energy transition and sustainable development. Due to its industrial distributed PV subsidy support policy, China has witnessed rapid growth in distributed PV industrial projects, leading to the formation of a mature market trading mechanism. This paper, focusing on China’s industrial distributed PV and its user, aims to explore how the PV system manufacturer (PSM) and PV system service provider (PSSP) can optimize the combination of “recycling mode & power structure” to simultaneously achieve multiple performance improvements, including those in economy, society, and environment (ESS) in the photovoltaic closed-loop supply chain (PV-CLSC), in consideration of the government’s PV subsidy policy. Therefore, by using three game-theoretical approaches including Nash game existed between the PSM and the PSSP under equal power and the Stackelberg game respectively led by PSM and PSSP, the optimal decisions of the PSM and PSSP, and the effective government subsidies under different combinations are obtained. Conclusions show that: To achieve individual optimal economic performance, both PSM and PSSP, as recyclers, invariably prefer a dominant position and choose to conduct recycling activities independently. For social welfare and subsidy efficiency, the government consistently tends to choose the PSM recycling mode in which the PSM and PSSP are expected to be in an equal power structure. Both in the PSM recycling and PSSP recycling modes, the government subsidy is smaller when two members are under the equal position than that respective under the dominant position, and in the latter scenario, the one with the advantage can mainly obtain the difference in the increased government subsidy.

Optimization of long cycle emission reduction paths for new-type power system considering electric-thermal coupling

The carbon factor is the core driving force behind the low-carbon transformation of the power system. The study of Emission Reduction Paths (ERPs) has become a key issue for the New-type Power System to achieve clean and low-carbon goals. In order to measure the relationship between ERP and the economy, this paper considers the retirement requirements of coal-fired power units and emission reduction requirements on a long cycle planning scale, and constructs a multi-scenario planning model that considers electric-thermal coupling, enabling the determination of installed capacity for power and heat sources each year. The effectiveness of the proposed model was verified using an improved IEEE-39 bus power system. A case study was conducted to analyze the economic performance of the system based on the selected ERP set. The results showed that under the rear acceleration’s ERP, the system could achieve optimal economic performance based on the selected ERP set.

Cross-level steam load smoothing and optimization in industrial parks using data-driven approaches

This study focuses on the integrated energy production system in industrial parks, addressing the problem of stable load dispatch of equipment under demand fluctuations. A cross-level method for steam load smoothing and optimization is proposed, aiming to achieve stable production and optimal economic performance through three levels of integration: load forecasting, load dispatch, and load regulation. Unlike traditional methods that directly use load forecasting values, heat network elasticity is presented as a buffer between demand and supply. Constraints for minimal changes in equipment load and operational parameters are established for smooth regulation. Industrial cases demonstrate that the load forecasting model has mean absolute percentage errors of 2.44% and 1.68% for medium-pressure and low-pressure steam, respectively, meeting accuracy requirements. The modified supply-side load smoothness is effectively improved by considering heat network elasticity. The method increases boiler efficiency by 1.92%, reducing average coal consumption by 0.92 t/h. Compared to manual operation, the proposed model leads to an average increase of 5.69 MW in power generation and an average reduction of 10.81% in coal-to-electricity ratio. This study verifies the importance of smooth integration across different levels and analyzes the effective response of the proposed method to the uncertainty in load forecasting. The method demonstrates the enormous potential of data-driven methods in achieving safe, economical, and sustainable production in industrial parks.

Optimal dispatch approach for rural multi-energy supply systems considering virtual energy storage

In response to the underutilization of energy and insufficient flexible operation capability of rural energy supply systems in China, this study proposes an optimal dispatch approach for a rural multi-energy supply system (RMESS) considering virtual energy storage (VES). First, to enable the flexible utilization of rural biomass resources and the thermal inertia of residential building envelopes, this study constructed VES-I and VES-II models that describe electrical-thermal and electrical-gas coupling from an electrical viewpoint. Subsequently, an RMESS model encompassing these two types of VES was formulated. This model delineates the intricate interplay of multi-energy components within the RMESS framework and facilitates the precise assessment of the adjustable potential for optimizing RMESS operations. Based on the above models, a day-ahead optimal dispatch model for an RMESS considering a VES is proposed to achieve optimal economic performance while ensuring efficient energy allocation. Comparative simulations validated the effectiveness of the VES modeling and the day-ahead optimal dispatch approach for the RMESS.

17 Nutritional Consequences of Formulating pig Diets with Low Energy Values Using Fibrous Rich Byproducts

Abstract The objective of this study is to provide insight in how to formulate pig diets in the most economical way in times of high feedstuff prices. Regarding this, energy level and the way of calculating energy in swine feeds will be taking into consideration, as well as the nutrients to energy ratios. Moreover, the effects of diet concentration on feed intake and growth performance of pigs will be evaluated. The lowest cost per energy value in swine feeds can be assessed by iterative simulations in least cost calculations using linear programming. In this case, a fixed nutrient to energy ratio has to be maintained for each cost per energy value that is calculated. Since feedstuff prices are subject to changes, these calculations have to be made on a regular basis. A dataset of 6 growth performance experiments in growing finishing (GF) pigs varying in energy values performed at Schothorst Feed Research (SFR) was analyzed. While decreasing the net energy value of the feed (at fixed nutrient to energy ratios), feed intake and energy conversion increased, while energy intake, daily gain and feed conversion ratio decreased. In general, pigs fed diets with reduced energy concentration are prone to maintain constant daily energy intake by eating more feed until feed intake is limited by other factors, such as physical gut capacity or certain dietary components (Li and Patience, 2017). In the same SFR analysis, the effect of the lysine (and other essential AA) to NE ratio was investigated. While decreasing this ratio, feed intake and energy intake were unaffected, while daily gain decreased, and the feed conversion ratio and energy conversion ratio increased. Another analysis of several GF experiments conducted at SFR was done to assess the optimal amino ccid (SID EAA) content of grower/finisher pig feeds in relation to technical performance, carcass characteristics and profitability. It was concluded that decreasing the SID AA/NE ratio to a certain extend will decrease technical performance (ADG and lean meat %) but increase economical results. However, it must be taken into account that optimal economic performance depends on market situation (feedstuff prices) and production goals (optimal ADG, carcass quality or costs/kg pork). In the current situation with high feedstuff prices, the inclusion of fibrous rich byproducts in the Dutch market may be more economical than corn and soybean meal. For an optimal estimation of the proportion of energy of those fibrous byproducts that will be attributed to the growth and maintenance energy requirements of the pigs, the net energy system is more appropriate than the metabolizable energy (ME) system, because the ME system overestimates the proportion of energy that will be used for growth and maintenance.

Beyond Neoliberalism and Capital Accumulation Theory: Evidence Learning from Turkey’s Economy

Neoliberalism is both a body of economic theory and a policy stance. The neoliberal theory claims that a largely unregulated capitalist system (“a free market economy”) embodies the ideal of free individual choice and achieves optimum economic performance.
 The phase of “embedded liberalism” was succeeded by an era of embedded neoliberalism in which the contradictions of global capitalism were veiled by the hegemonic ideology of individual freedom and prosperity in the nineteenth century.
 The conditions for a capitalist economy in Turkey were established in the 1920s within the republican political system, which supported the development of national economic capability for capitalist accumulation—albeit with strict government planning of the budget and control over the private sector and foreign trade and investment. After 1980, neoliberal economic reform weakened the statist system and, particularly since 2001, transformed Turkey into a transnational state better suited to the demands of a global economy.
 This paper tries to identify and find the link between neoliberalism and capital accumulation theory based on learning about Turkey’s economy before and after the crisis. We found that the outcome of neoliberal restructuring experiments depends crucially on pre-existing and changing power structures and relations in the course of state transformations. Thus, Turkey shifted to a neo-liberal model through voluntary choice but as an inevitable and forced outcome of a major balance of payments crisis associated with the exhaustion of the import-substitution model of industrialization.

Real-time adaptive sparse-identification-based predictive control of nonlinear processes

This study introduces a sparse identification-based model predictive control (MPC) framework that incorporates on-line updates of the sparse-identified model to account for nonlinear dynamics and model uncertainty in process systems. The methodology involves obtaining a nonlinear first-order ordinary differential equation model using sparse identification for nonlinear dynamics (SINDy), which is integrated into two control schemes: Lyapunov-based MPC (LMPC) for achieving steady-state operation and Lyapunov-based economic MPC (LEMPC) for achieving both closed-loop stability and optimal economic performance. To improve prediction accuracy, an on-line model update scheme is proposed for the SINDy models. Specifically, an error-trigger mechanism that utilizes prediction errors and then uses the most recent process data to update the parameters of the SINDy model in real-time is designed. By incorporating the error-triggered on-line model updates in the SINDy-based LMPC and LEMPC, the dynamic performance of the process is enhanced, ensuring closed-loop stability, optimality, and smooth control actions. Following theoretical results on the boundedness of the closed-loop states and detailed discussions on the selection criteria for parameters of the error-triggered SINDy update scheme, the effectiveness of the proposed methodology is demonstrated through a chemical process example with time-varying disturbances under the LEMPC framework.

Performance analysis and optimization study of a new supercritical CO2 solar tower power generation system integrated with steam Rankine cycle

Currently, the supercritical CO2 solar tower power generation (S-CO2 STPG) has become a research hotspot, but due to S-CO2 Brayton cycle characteristics, the solar energy utilization rate of the system is low. Therefore, a new S-CO2 STPG system integrated with steam Rankine (SR) cycle is first proposed. The SR cycle absorbs the waste heat of the S-CO2 Brayton cycle, and the introduction of the SR cycle can increase the solar energy utilization rate. The research is based on the simulation results, the system model is developed by Ebsilon, and system operation calculation is developed by MATLAB. The daily and monthly performances of the new S-CO2 STPG system integrated with SR cycle are compared with those of conventional S-CO2 STPG system in detail. The system location is Bakersfield. The comparative analysis results show that compared with the conventional system, the monthly power output for the new system rises significantly, especially in summer. The new system can effectively improve the solar energy utilization rate. The effect of SR cycle power output on new system performance is studied. Increasing SR cycle power output can improve the thermal energy storage subsystem and solar field subsystem performances. The optimal SR cycle power output is related to the solar radiation level. The Fargo, Bakersfield and Phoenix are selected as three places representing low-direct normal irradiance (DNI), medium-DNI and high-DNI districts, respectively. For the medium-DNI and high-DNI districts, the SR cycle power outputs corresponding to the optimal thermal performance and optimal economic performance are 20 MW and 15 MW, respectively; for the low-DNI district, those are 15 MW and 5 MW, respectively.

Social and economic aspects of treatment of patients with medium (W2) and large (W3) postoperative ventral hernias

The article describes social and economic aspects of the treatment of patients with medium and large postoperative ventral hernias . The study was based on the results of treatment of 181 patients operated by endovideosurgical and open methods for postoperative ventral hernias . The stratification of patients was carried out on the basis of the mod ern classification of postoperative hernias of the EHS approved in the national clinical guidelines . The first main group of patients who underwent laparoscopic hernioplasty using the IPOM+ technique ( intraperitoneal onlay mesh ) consisted of 47 people . The second main group included 12 patients operated using the preperitoneal eTEP technique ( extended total extraperitoneal plasty ). The control group consisted of 122 patients with postoperative ventral hernias who underwent traditional ( open ) hernioplasty : using the techniques of onlay – 35 patients , inlay – 12, sublay – 75. Preoperative examination before planned minimally invasive hernioplasty included routine laboratory and instrumental examinations . The exceptions were patients with stage II and III obesity , as well as large postoperative ventral hernias , patients who underwent computed tomography with abdominometry . The economic efficiency of the treated patients was calculated using standardized formulas . It has been established that the complete e- TEP operation statistically reliably allows to get a significant economic effect compared to the laparoscopic IPOM surgery . IPOM endovideohernioplasty can be used in patients with a combined surgical disease of the abdominal organs in the case of simultaneous intervention . Traditional hernioplasty in patients with large and giant hernias with reduction of abdominal volume are the operations of choice and significantly increase the economic efficiency of the medical hospital . A modern surgical hospital should be able to perform any variants of both traditional and endovideosurgical hernioplasty in order to provide effective medical care and achieve optimal economic performance in any of the existing health insurance systems .

Energy Hub Optimal Scheduling and Management in the Day-Ahead Market Considering Renewable Energy Sources, CHP, Electric Vehicles, and Storage Systems Using Improved Fick’s Law Algorithm

Coordinated energy scheduling and management strategies in the energy hub plan are essential to achieve optimal economic performance. In this paper, the scheduling and management framework of an energy hub (EH) is presented with the aim of energy profit maximization in partnership with electricity, natural gas, and district heating networks (EGHNs) considering the coordinated multi-energy management based on the day-ahead market. The optimum capacity of EH equipment, including photovoltaic and wind renewable energy sources, a combined heat and power system (CHP), a boiler, energy storage, and electric vehicles is determined in the day-ahead market using the improved Fick’s law algorithm (IFLA), considering the energy profit maximization and also satisfying the linear network and hub constraints. The conventional FLA is inspired by the concept of Fick’s diffusion law, and, in this study, its performance against premature convergence is improved by using Rosenbrock’s direct rotational method. The performance of the IFLA when applied to EH coordinated scheduling and management problems with the aim of profit maximization is compared with the conventional FLA, particle swarm optimization (PSO), and manta ray foraging optimization (MRFO) methods. The results show that the proposed scheduling and multi-energy management framework achieves more energy profit in the day-ahead electricity, gas, and heating markets by satisfying the operation and EH constraints compared to other methods. Furthermore, according to the findings, the increased (decreased) demand and the forced outage rate caused a decrease (increase) in the EH profit. The results show the effectiveness of the proposed framework to obtain the EH maximum energy profit in the day-ahead market.

FINANCIAL PLANNING OF ENTERPRISE ACTIVITIES BASED ON ORGANIZATIONAL DESIGN

In the course of the study, the essence of the relationship between organizational design and financial planning was analyzed. It has been established that, despite the variety of approaches to financial planning in practice, its functions are implemented in isolation in relation to organizational design, as a result of which the possibility of achieving an optimal financial result is reduced. It has been established that ensuring the relationship between financial planning and organizational design is possible with the introduction of an integrated approach. A number of tasks are given that should be solved at the stage of organizational and financial design in order to build an integral model of the enterprise. It is proposed to use an integral model that allows organizing management processes based on the interaction of production cycles and the organizational structure of the enterprise, which will optimize the relationship between organizational and financial planning at the enterprise. Financial planning will allow you to fully use the potential of the enterprise to achieve the desired financial results in the planning period. The presented model has a modular structure. The set of interacting modules makes it possible to take into account the peculiarities of the structural organization and production cycles of a particular enterprise. Separate structural subdivisions and stages of production cycles are represented by separate modules interacting with each other according to the selected algorithm. To build modules of structural elements and components of the production cycle, methods of mathematical and simulation modeling were used. The integral model makes it possible to study the interaction between production cycles and structural organization in two modes - multi-process and mono-process. The multi-process mode is used to study manufacturing enterprises with a large range of products. The single-process simulation mode is used to study highly specialized enterprises with one production cycle, as well as enterprises with a multi-process operation mode to determine the minimum time for each production cycle. The paper presents an algorithm for modeling the relationship between financial and organizational planning, which makes it possible to investigate the need for labor, material and financial resources of an enterprise. The model makes it possible to analyze various options for the interaction of a structural organization and production cycles, as well as to predict the optimal economic performance of an enterprise at the stage of organizational design and financial planning. It is concluded that due to the close relationship between financial and organizational planning identified with the help of an integral model, it becomes possible to predict the desired financial results using the potential capabilities of an enterprise for structural reorganization or the creation of a new organizational structure.

An intensified energy-saving architecture for side-stream extractive distillation of four-azeotrope mixtures considering economic, environmental and safety criteria simultaneously

Side-stream extractive distillation is used in separating azeotropic mixtures due to its advantages in energy-saving. However, environmental and safety aspects should also be considered in most chemical industries. Thus, this work focuses on thermodynamic analysis, multi-objective optimization and multi-criteria decision making. The main contributions of this work are developing the intensified side-stream extractive distillation for complex ternary azeotropic mixture, obtaining the trade-offs between the economic, environmental and safety impacts of SSED processes and determining the best sustainable SSED process according to objective mathematical analysis. A systematic intensified architecture including conceptual design, multi-objective optimization and multi-criteria decision making is proposed. Firstly, three strategies of side-stream extractive distillation (i.e., SSED-1, SSED-2, and SSED-3) are proposed via the thermodynamic analysis including quaternary phase diagram. Subsequently, the three strategies are optimized via the multi-objective particle swarm algorithm simultaneously using total annual costs (TAC), CO2 emission and process route index (PRI) as objective functions. Finally, the optimal economic, environmental and safety performance of such a complex system is determined by the technique for order of preference by similarity to ideal solution method with entropy weighting information. The results indicate that the introduction of the side-stream for extractive distillation could decrease the exergy loss and increase the thermodynamic efficiency. The SSED-1 process shows that the best performance in economic, safety and environmental aspects, which reduce 19.21% of TAC, 5.24% of PRI and 16.80% of CO2 emission, respectively.

Performance study of a novel supercritical CO2 solar-coal supplementary power generation system

• New supercritical CO 2 solar-coal supplementary power generation system is proposed. • The annual solar generating power accounts for 61.29% of the total power output. • Standard coal consumption rate is 161.11 g/kWh lower than pure coal-fired system. • The new system performances with the change of the load rate are revealed. • Effects of solar multiple and thermal energy storage capacity on new system are studied. To reduce the CO 2 emission and improve the solar energy utilization rate, a novel supercritical CO 2 solar-coal supplementary power generation system is proposed. Compared with the previous studies on supplementary systems, the novel system takes solar energy as the main heat source instead of coal, which greatly increases the proportion of solar energy input. The results show that, when the solar multiple (parameter representing the area of the heliostat field) is 3 and the thermal energy storage capacity is 16 h, on the summer and winter solstices, the proportions of solar generating power are 100% and 57.15%, respectively. The novel system can operate steadily during the whole year. The annual solar generating power is 161.07 GWh, accounting for 61.29%. The standard coal consumption rate of the novel system is 101.76 g/kWh, 161.11 g/kWh lower than that of the pure coal-fired system. The exergy efficiency for the novel system increases with an increasing operation load rate. Under 50%, 75%, 100%, and 125% load rates, the exergy efficiencies are 16.7%, 25.0%, 33.4%, and 38.0%, respectively. It is the first time to study the effects of the solar multiple and the thermal energy storage capacity on the energy, exergy, environmental, and economic performances of the supercritical CO 2 solar-coal supplementary power generation system. When the thermal energy storage capacity is 16 h, the solar multiple corresponding to the optimal economic performance is 2.5.