Parametric Energy and Economic Analysis ofModified Combined Cycle Power Plant with Vapor Absorption and Organic Rankine Cycle

To meet the escalating electricity demand and rising fuel costs,along with notable losses in power transmission,exploring alternative solutions is imperative.Gas turbines demonstrate high efficiency under ideal International Organization for Standardization(ISO)conditions but face challenges during summer when ambient temperatures reach 40℃.To enhance performance,the proposal suggests cooling inlet air by 15℃using a vapor absorption chiller(VAC),utilizing residual exhaust gases from a combined cycle power plant(CCPP)to maximize power output.Additionally,diverting a portion of exhaust gases to drive an organic Rankine cycle(ORC)for supplementary power generation offers added efficiency.This integrated approach not only boosts power output but alsominimizes environmental impact by repurposing exhaust gases for additional operations.This study presents a detailed energy and economic analysis of a modified combine cycle power plant,in Kotri,Pakistan.R600A is used as organic fuel for the ORC while LiBr-H2O solution is used for the VAC.Two performance parameters,efficiency and energy utilization factor,Four energetic parameters,Work output of ORC,modified CCPP,original CCPP and cooling rate,and one economics parameter,payback period were examined under varying ambient conditions and mass fraction of exhaust gases from outlet of a gas turbine(ψ).A parametric investigation was conducted within the temperature range of 18℃to 50℃,relative humidity between 70%and 90%,and theψranging from 0 to 0.3.The findings reveal that under elevated ambient conditions(40℃,90%humidity)withψat 0,the Energy Utilization Factor(EUF)exceeds 60%.However,the ORC exhibits a low work output of 100KWalongside a high cooling load of 29,000 kW.Conversely,the modified system demonstrates an augmented work output of approximately 81,850 KWcompared to the original system’s 78,500KW.Furthermore,the integration of this systemproves advantageous across all metrics.Additionally,the payback period of the system is contingent on ambient conditions,with lower conditions correlating to shorter payback periods and vice versa.

Application of Combined Cycle in Modernized Retrofit of Old Thermal Power Plants

This article expounds the advantages and three schemes of applying combined cycle to the modernized retrofit of old thermal power plants. Through analyzing and comparing technical economics of these three schemes, it is concluded that to use feedwater heating and heat recovery steam generator (HRSG) is suitable for the units with unit capacity below 100 MW, while to use exhaust gas reburning is suitable for units with unit capacity of 125 MW, 200 MW and above.

Model Selection of Gas Turbine for Large Scale Gas-Fired Combined Cycle Power Plant

This paper briefs the configuration and performance of large size gas turbines and their composed combined cycle power plants designed and produced by four large renown gas turbine manufacturing firms in the world, providing reference for the relevant sectors and enterprises in importing advanced gas turbines and technologies.

Demonstration of Pilot Scale Large Aperture Parabolic Trough Organic Rankine Cycle Solar Thermal Power Plant in Louisiana

During the calendar year of 2012 the University of Louisiana at Lafayette in conjunction with CLECO Power LLC (CLECO) has constructed and commissioned a pilot scale parabolic trough solar thermal power plant for the first time in Louisiana. The large aperture trough (LAT) solar collectors were provided by Gossamer Space Frames and are coupled with an organic Rankine cycle (ORC) power block provided by ElectraTherm, Inc. for study of the feasibility of cost-effective commercial scale solar thermal power production in Louisiana. Supported by CLECO and providing power to the existing CLECO grid, the implementation of state-of-the-industry collector frames, mirrors, trackers, and ORC power block is studied under various local weather conditions which present varied operating regimes from existing solar thermal installations. The solar collectors provide a design output of 650 kWth and preliminary actual performance data from the system level is presented. The optimal size, configuration and location for such a plant in the given solar resource region are being studied in conjunction with CLECO’s search for optimal renewable energy solutions for the region. The pilot scale size of the facility and implementation of the simpler ORC allow remote operation of the facility and flexibility in operating parameters for optimization studies. The construction of the facility was supported by the Louisiana Department of Natural Resources, the U.S. Department of Energy, and CLECO. The continued operation of the plant is supported by CLECO Power LLC and the University of Louisiana at Lafayette.

Monte Carlo Simulation of a Combined-Cycle Power Plant Considering Ambient Temperature Fluctuations

A combined-cycle power plant (CCPP) is broadly utilized in many countries to cover energy demand due to its higher efficiency than other conventional power plants. The performance of a CCPP is highly sensitive to ambient air temperature (AAT) and the generated power varies widely during the year with temperature fluctuations. To have an accurate estimation of power generation, it is necessary to develop a model to predict the average monthly power of a CCPP considering ambient temperature changes. In the present work, the Monte Carlo (MC) method was used to obtain the average generated power of a CCPP. The case study was a combined-cycle power plant in Tehran, Iran. The region’s existing meteorological data shows significant fluctuations in the annual ambient temperature, which severely impact the performance of the mentioned plant, causing a stochastic behavior of the output power. To cope with this stochastic nature, the probability distribution of monthly outdoor temperature for 2020 was determined using the maximum likelihood estimation (MLE) method to specify the range of feasible inputs. Furthermore, the plant was accurately simulated in THERMOFLEX to capture the generated power at different temperatures. The MC method was used to couple the ambient temperature fluctuations to the output power of the plant, modeled by THERMOFLEX. Finally, the mean value of net power for each month and the average output power of the system were obtained. The results indicated that each unit of the system generates 436.3 MW in full load operation. The average deviation of the modeling results from the actual data provided by the power plant was an estimated 3.02%. Thus, it can be concluded that this method helps achieve an estimation of the monthly and annual power of a combined-cycle power plant, which are effective indexes in the economic analysis of the system.

ISSUES AND SUGGESTIONS ON LEVYING SO_2 EMISSION GHARGES TO THERMAL POWER PLANTS

This paper analyzes 9 essentials in trial collecting SO2 emission charges based on the relevant legislative policies, summarizes and analyzes the actual practices of collecting and using SO2 emission charges in power industry, and combining the status of power system reform, puts forward some recommendations about reasonably collecting and using SO2 emission charges and prompting power plants to take measures of desulfurization.

Simulation and performance analysis of organic Rankine cycle combined heat and power system

To improve the overall thermal efficiency of the organic Rankine cycle（ ORC）, a simulation study was carried out for a combined heat and power（ CHP） system, using the Redlich-Kuang-Soave（ RKS） equation of state. In the system,R245 fa was selected as the working fluid. A scroll expander was modeled with empirical isentropic expansion efficiency.Plate heat exchangers were selected as the evaporator and the condenser, and detailed heat transfer models were programmed for both one-phase and two-phase regions. Simulations were carried out at seven different heat source temperatures（ 80,90, 100, 110, 120, 130, 140 ℃） in combination with eight different heat sink temperatures（ 20, 25, 30, 35, 40, 45, 50,55 ℃）. Results showthat in the ORC without an internal heat exchanger（ IHE）, the optimum cycle efficiencies are in the range of 7. 0% to 7. 3% when the temperature differences between the heat source and heat sink are in the range of 70 to90 ℃. Simulations on CHP reveal that domestic hot water can be produced when the heat sink inlet temperature is higher than40 ℃, and the corresponding exergy efficiency and overall thermal efficiency are 29% to 56% and 87% to 90% higher than those in the non-CHP ORC, respectively. It is found that the IHE has little effect on the improvement of work output and efficiencies for the CHP ORC.

Progress in Research and Development of Molten Chloride Salt Technology for Next Generation Concentrated Solar Power Plants

Concentrated solar power(CSP)plants with thermal energy storage(TES)system are emerging as one kind of the most promising power plants in the future renewable energy system,since they can supply dispatchable and low-cost electricity with abundant but intermittent solar energy.In order to significantly reduce the levelized cost of electricity(LCOE)of the present commercial CSP plants,the next generation CSP technology with higher process temperature and energy efficiency is being developed.The TES system in the next generation CSP plants works with new TES materials at higher temperatures(>565℃)compared to that with the commercial nitrate salt mixtures.This paper reviews recent progressin research and development of the next generation CSP and TES technology.Emphasis is given on theadvanced'TES technology based on molten chloride salt mixtures such as MgCl_(2)/NaCl/KCl which hassimilar thermo-physical properties as the commercial nitrate salt mixtures,higher thermal stability(>800℃),and lower costs(<0.35USD·kg^(-1)).Recent progress in the selection/optimization of chloridesalts,determination of molten chloride salt properties,and corrosion control of construction materials(eg.,alloys)in molten chlorides is reviewed.

Application of Supercritical CO2 Gas Turbine for the Fossil Fired Thermal Plant

A supercritical CO2 gas turbine cycle can produce power at high efficiency and the gas turbine is compact compared with the steam turbine. Therefore, it is very advantageous power cycle for the medium temperature range less than 650 ℃. The purpose of this paper is to show how it can be effectively applied not only to the nuclear power but also to the fossil fired power plant. A design of 300 MWe plant has been carried out, where thermal energy of flue gas leaving a CO2 heater is utilized effectively by means of economizer and a high cycle thermal efficiency of 43.4 % has been achieved. Since the temperature and the pressure difference of the CO2 heater are very high, the structural design becomes very difficult. It is revealed that this problem can be effectively solved by introducing a double expansion turbine cycle. The component designs of the CO2 heater, the economizer, supercritical CO2 turbines, compressors and the recuperators are given and it is shown that these components have good performances and compact sizes.

DESIGN OF COMBINED CYCLE GENERATION SYSTEM WITH HIGH TEMPERATURE FUEL CELL AND STEAM TURBINE

For environment protection and high efficiency, development of new conceptpower plant has been required in China. The fuel cell is expected to be used in a power plant as acentralized power Station or distributed power plant. It is a chemical power generation device thatconverts the energy of a chemical reaction directly into electrical energy and not limited by Carnotcycle efficiency. The molten carbonate fuel cell (MCFC) power plant has several attractive featuresi.e. high efficiency and lower emission of NO_x and SO_x A combined cycle generation system withMCFC and steam turbine is designed. Its net electrical efficiency LHV is about 55 percent.

Carnot Factor of a Vapour Power Cycle with Regenerative Extraction

The present paper describes the energy analysis of a regenerative vapour power system. The regenerative steam turbines based on the Rankine cycle and comprised of vapour extractions have been used industrially since the beginning of the 20th century, particularly regarding the processes of electrical production. After having performed worked in the first stages of the turbine, part of the vapour is directed toward a regenerative exchanger and heats feedwater coming from the condenser. This process is known as regeneration, and the heat exchanger where the heat is transferred from steam is called a regenerator (or a feedwater heater). The profit in the output brought by regenerative rakings is primarily enabled by the lack of exchange of the tapped vapour reheating water with the low-temperature reservoir. The economic optimum is often fixed at seven extractions. One knows the Carnot relation, which is the best possible theoretical yield of a dual-temperature cycle;in a Carnot cycle, one makes the assumption that both compressions and expansions are isentropic. This article studies an ideal theoretical machine comprised of vapour extractions in which each cycle partial of tapped vapour obeys these same compressions and isentropic expansions.

A practical approach to improve alarm system performance: Application to power plant

Process safety in chemical industries is considered to be one of the important goals towards sustainable development. This is due to the fact that, major accidents still occur and continue to exert significant reputational and financial impacts on process industries. Alarm systems constitute an indispensable component of automation as they draw the attention of process operators to any abnormal conditi on in the plant. Therefore, if deployed properly, alarm systems can play a critical role in helping plant operators ensure process safety and profitability. How-ever, in practice, many process plants suffer from poor alarm system configuration which leads to nuisance alarms and alarm floods that compromise safety. A vast amount of research has primarily focused on developing sophisticated alarm management algorithms to address specific issues. In this article, we provide a simple, practical, systematic approach that can be applied by plant engineers (i.e., non-experts) to improve industrial alarm system performance. The proposed approach is demonstrated using an industrial power plant case study.

Review on Thermal Power Automation Development in China

A review on thermal power plant automation development in China over 50 years is presented. The level of thermal power automation is introduced, especially for 200 MW and above units which are clarified into three categories by grade. The conditions, existing problems, relevant solutions and policies are summarized chronologically in aspects of centralized control, automatic regulation and controllability of main and auxiliary units, turbine control system, furnace security protection, and computer application in thermal power plants. This paper also points out the development tendency of thermal power plant automation and concepts of some vocabularies.

Optimization Potentials for the Waste Heat Recovery of a Gas-Steam Combined Cycle Power Plant Based on Absorption Heat Pump

A new waste heat recovery system is presented to recover exhausted steam waste heat from the steam turbine by absorption heat pump(AHP) in a gas-steam combined cycle(GSCC) power plant. The system can decrease energy consumption and further improve the energy utilization. The performance evaluation criteria are calculated, and exergy analysis for key components are implemented in terms of the energy and exergy analysis theory. Besides, the change of these criteria is also revealed before and after modification. The net power output approximately increases by 21738 kW, and equivalent coal consumption decreases by 5.58 g/kWh. A 1.81% and 1.92% increase in the thermal and exergy efficiency is respectively obtained in the new integrated system as the heating load is 401095 kJ at 100% condition. Meanwhile, the appropriate extraction parameters for heating have been also analyzed in the two systems. The proposed scheme can not only save energy consumption but also reduce emission and gain great economic benefit, which is proven to be a huge potential for practical application.

Recent Developments in Integrated Solar Combined Cycle Power Plants

Global concern for depleting fossil fuel reserves have been compelling for evolving power generation options using renewable energy sources. The solar energy happens to be a potential source for running the power plants among renewable energy sources. Integrated Solar Combined Cycle(ISCC) power plants have gained popularity among the thermal power plants. Traditional ISCC power plants use Direct Steam Generation(DSG) approach. However, with the DSG method, the ISCC plant’s overall thermal efficiency does not increase significantly due to variations in the availability of solar energy. Thermal Energy Storage(TES) systems when integrated into the solar cycle can address such issues related to energy efficiency, process flexibility, reducing intermittency during non-solar hours. This review work focuses and discusses the developments in various components of the ISCC system including its major cycles and related parameters. The main focus is on CSP technologies, Heat Transfer Fluid(HTF), and Phase Change Material(PCM) used for thermal energy storage. Further, study includes heat enhancement methods with HTF and latent heat storage system. This study will be beneficial to the power plant professionals intending to modify the solar-based Combined Cycle Power Plant(CCPP) and to retrofit the existing Natural Gas Combined Cycle(NGCC) plant with the advanced solar cycle.

Performance Improvement of Combined Cycle Power Plant Based on the Optimization of the Bottom Cycle and Heat Recuperation

Many F class gas turbine combined cycle （GTCC） power plants are built in China at present because of less emission and high efficiency. It is of great interest to investigate the efficiency improvement of GTCC plant. A combined cycle with three-pressure reheat heat recovery steam generator （HRSG） is selected for study in this paper. In order to maximize the GTCC efficiency, the optimization of the HRSG operating parameters is performed. The operating parameters are determined by means of a thermodynamic analysis, i.e. the minimization of exergy losses. The influence of HRSG inlet gas temperature on the steam bottoming cycle efficiency is discussed. The result shows that increasing the HRSG inlet temperature has less improvement to steam cycle efficiency when it is over 590℃. Partial gas to gas recuperation in the topping cycle is studied. Joining HRSG optimization with the use of gas to gas heat recuperation, the combined plant efficiency can rise up to 59.05% at base load. In addition, the part load performance of the GTCC power plant gets much better. The efficiency is increased by 2.11% at 75% load and by 4.17% at 50% load.

Identifying Critical Components of Combined Cycle Power Plants for Implementation of Reliability-centered Maintenance

Maintenance scheduling and asset management practices play an important role in power systems,specifically in power generating plants.This paper presents a novel riskbased framework for a criticality assessment of plant components as a means to conduct more focused maintenance activities.Critical components in power plants that influence overall system performance are identified by quantifying their failure impact on system reliability,electric safety,cost,and the environment.Prioritization of plant components according to the proposed risk-based method ensures that the most effective and techno-economic investment decisions are implemented.This,in turn,helps to initiate modern maintenance approaches,such as reliability-centered maintenance(RCM).The proposed method is applied to a real combined cycle power plant(CCPP)in Iran,composed of two gas turbine power plants(GTPP)and one steam turbine power plant(STPP).The results demonstrate the practicality and applicability of the presented approach in real world practices.

A Fuzzy Homogeneous Combustion Control System

This paper presents the scheme of the Fuzzy Homogeneous Combustion Control System (FHCCS) and its practical use on site. The operating results of the system show that FHCCS can not only operate normally, but also guarantee the homogeneous combustion in each level of burner and at optimal air coal ratio of each burner. Some engineering problems about FHCCS implementation are discussed in this paper.

CCPP机组余热锅炉高压蒸发器泄漏分析与处理

燃气-蒸汽联合循环机组(CCPP)作为高效能源转换系统,在钢铁等工业领域得到广泛应用。余热锅炉作为CCPP机组的核心部件,其稳定运行直接关系到整个机组的效率和安全性。文章针对某钢厂燃气轮机组配套余热锅炉高压蒸发器上部迎烟气面频繁泄漏问题进行了深入研究,分析泄漏原因为其下联箱内沉积物导致蒸发器管内水流量减小,进而产生汽水混合物的冲击腐蚀,同时炉膛局部区域的“烟气走廊”现象加剧了这一腐蚀过程。针对这一问题,采取更换泄漏管段、改造下联箱定排管系统以提高排污效率、修复和完善烟气挡板以减少“烟气走廊”形成、优化定期排污操作以及制定定期的检查和维护计划等措施,有效地解决了高压蒸发器的泄漏问题,提高了设备的稳定性和安全性。

电厂热控仪表故障及预防措施研究

电厂热控仪表用于监测和控制各种热控参数,确保电厂的安全运行和高效发电。然而,由于长期使用和环境影响,热控仪表存在故障风险。为确保热控仪表运行的稳定性,以电磁流量计、压差流量计等热控仪表的常见故障问题为例,分析故障的原因和检修处理措施,并提出具体的故障预防措施。期望该研究为相关从业人员提供参考与借鉴,进而保障电力系统的可靠性和稳定性。