Study on the Energy Dispatch Strategy of PV Power Plant

Now the energy efficiency of the PV power plant is low.For this case,this paper presents a PV power plant energy scheduling strategy.It includes new grid scheme and scheduling algorithm.Through the establishment of PV power station network model and the method of computer simulation of its scheduling algorithm,this paper describes its realization way,and then proves that the scheduling strat egy is correct and the effectiveness of improving energy conversion rate.At the same time,the PV power station scheduling strategy aslo re duces the environmental pollution,and alleviates the energy crisis and environmental crisis.

Performance of a 270 MW Gas Power Plant Using Exergy and Heat Rate

The performance of a 270 MW (9 × 30 MW) AES Corporation barge mounted gas turbine power plant in Nigeria is evaluated using the heat rate and entropy generation by the components of the plant to characterize the irreversibility in each component when operating at different loads between 90% and 25%. The power plants have the peculiarity that three of the plants were supplied by three (3) different Original Equipment Manufacturers (OEM);A, B and C. This study is sequel to the fact that the gas turbines were the first independent power plants in the country and after more than fifteen years of operation, it is reasonable to evaluate the performance of the major components. By analyzing the thermodynamic performance of these components, the study demonstrates the utility value of exergy efficiency as an important parameter in the evaluation of major components in a gas power plant. Exergy efficiency is shown to be an important parameter in ranking the power plant components, identifying and quantifying the possible areas of reduction in thermodynamic losses and improvement in efficiencies. A new relationship is derived to demonstrate the correlation between the exergy efficiency and the heat rate of a 30 MW gas power plant. The prediction of the derived relationship correlates well with the observed operational performance of the 30 MW power plants. The combustion chamber in each of the plants provides the maximum exergy destruction during operation. Its exergy efficiency is shown to exhibit good correlation with its energy efficiency and the plant rational exergy. The implication is that from an operational and component selection viewpoint in the specifications of a gas power plant, knowledge of the Heat Rate which is usually provided by the OEM is adequate to make a reasonable inference on the performance of some critical components of the plant.

Efficiency Upgrade in PWRs

Most of the light water reactor power plants now operating or under construction use pressurized-water reactor (PWR). They are suffering of relatively low thermal efficiency which is around 33%. This would not only have a negative impact economically but also incurs environmental burden in terms of thermal pollution. In this paper, nuclear steam supply system of a typical PWR has been taken into consideration using 1000 MWe Bushehr nuclear power plant (BNPP) data. It is shown thermal efficiency could conceivably be increased by superheating live steam with natural gas up to around 40%, competing with similar fossil-fueled power plants. It is further shown that fuel cost (natural gas) as low as 0.12 Cent/MWe, extra power generated is feasible.

Clean Coal &High Carbon Efficiency Energy Engineering

Today we live in a world of Hydrocarbon Energy Carriers, where Carbon is always used as a Carrier for Hydrogen 1) Biomass (CH1.44O0.66 or C6H12O6);2) Natural Gas [NG] (CH4);3) Water Gas [C+H2O];4) Gasoline (C6H12, C7H18, C8H18, etc.);5) Kerosene (C17H36, C18H38, C19H40, C20H42, C21H44, C22H46, etc.) and;6) Crude Oil. The Carbon aggregates are all storable and have worthwhile, logistically manageable energy densities. But whenever recovering Energy from the Carbon molarities, CO2 gets emitted into the atmosphere, while separate use of Hydrogen Energy contents carried by the Carbon moieties would just generate water vapor. Hydrogen is also the most important intermediary in Refineries, hydrogenating lower grade Hydrocarbons into higher potencies, or for removing Sulfur by the formation of Hydrogen Sulfur, that can be dissociated after its segregation from the Hydrocarbon products. But most of the internal Hydrogen yields in Refineries today is used for onsite production of Ammonia as a basis for Energy fertilizers in high performance agriculture. Because Hydrogen is awkward to store and transport, most of it is currently used captive within large size centralized plants as a reactant for producing Hydrocarbon energy carriers, using the Carbon as a carrier for the Hydrogen moieties, to then be distributed over big enough areas for consumption of the such large scale plants’ volumes. With recently proven achievements of Hydrogen production from excess Wind & Solar Power by electrolysis, Hydrogen could become available in abundant quantities, to be distributed locally within the coverage area of the transmission grid such Wind & Solar installations are feeding into. In combination with Carbon as a reactant such abundant Hydrogen could also be synthesized into Hydrocarbon Energy Carriers and substitute fossil commodities.

Future of Architecture: Buildings as Power Plants

After the energy crisis in 1970s,buildings began to be used as a platform for the elements which produce energy from renewable energies to return them into energy producing power plants.This is a safe,clean and economic way to produce energy since the energy is produced where it is needed and they use renewable energy resources.So,it promises hope for the future energy production.Therefore,the aim of this study is to examine buildings which produce electricity by using renewable energy resources and to show that this is one of the safest,cleanest and most economic ways to be used to produce energy in the future.This is done by describing power plants and how buildings are used as power producing stations by the use of renewable energy resources or other energy producing materials,then by examining case studies which are constructed and already being used,case studies which are just a design that have not yet been constructed,and by making projections to the future energy producing techniques that are just a proposal in 2021.In the conclusion,buildings are proposed as the future power plants,either here on earth or on another planet like Mars.

Optimization and Innovation of Engineering Design for Ninghai Power Plant

In order to build a power plant with high efficiency,low investment and zero warm water discharge,a series of innovations are applied to the two 1 000-MW units of Ninghai Power Plant.The new technologies include the closed-circuit system for seawater cooling tower with a spraying area of 13 000 m2,the main buildings with reinforced concrete structure,the plasma ignition system for tower boiler and the fieldbus control system.Optimization measures are taken in some aspects,such as the open point of the turbine overload valves,the boiler dimensions,the technical process,the electric system,the building structures and the layout of the power plant.The units have been running for more than half a year with the thermal efficiency as high as 45.79% and without warm water discharged,which indicates that all the systems are safe and steady and the original purpose of optimization has been realized.

Power and efficiency optimizations for an open cycle two-shaft gas turbine power plant

In finite-time thermodynamic analyses for various gas turbine cycles,there are two common models:one is closed-cycle model with thermal conductance optimization of heat exchangers,and another is open-cycle model with optimization of pressure drop(PD)distributions.Both of optimization also with searching optimal compressor pressure ratio(PR).This paper focuses on an open-cycle model.A two-shaft open-cycle gas turbine power plant(OCGTPP)is modeled in this paper.Expressions of power output(PP)and thermal conversion efficiency(TCE)are deduced,and these performances are optimized by varying the relative PD and compressor PR.The results show that there exist the optimal values(0.32 and 14.0)of PD and PR which lead to double maximum dimensionless PP(1.75).There also exists an optimal value(0.38)of area allocation ratio which leads to maximum TCE(0.37).Moreover,the performances of three types of gas turbine cycles,such as one-shaft and two-shaft ones,are compared.When the relative pressure drop at the compressor inlet is small,the TCE of third cycle is the biggest one;when this pressure drop is large,the PP of second cycle is the biggest one.The results herein can be applied to guide the preliminary designs of OCGTPPs.

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.

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.

Low Steam Condition Heat Generator Combined with Advanced Oxy-Fuel Combustion LNG Gas Turbine for Power Generation

We propose a novel concept for power generation that involves the combination of a LSCHG （low-steam-condition heat generator）, such as a light water nuclear reactor or a biomass combustion boiler, with an advanced closed-cycle oxy-fuel combustion gas turbine-a type of complex and efficient oxy-fuel gas turbine. In this study, a LSCHG is designed to heat water to saturated steam of a few MPa, to assist in the generation of the main working fluids, instead of a compressor used in the advanced oxy-fuel gas turbine. This saturated steam can have a lower pressure and temperature than those of an existing nuclear power plant or biomass-fired power plant. We estimated plant performances in LHV （lower heating value） basis from a heat balance model based on a conceptual design of a plant for different gas turbine inlet pressures and temperatures of 1,300 ℃ and 1,500 ℃, taking into account the work to produce O2 and capture CO2. While the net power generating efficiencies of a reference plant are estimated to be about 52.0% and 56.0% at 1,300 ℃ and 1,500 ℃, respectively, and conventional LSCHG power plant is assumed to have an efficiency of about 35% or less for pressures of 2.5-6.5 MPa, the proposed hybrid plant achieved 42.8%-44.7% at 1,300 ℃ and 47.8%-49.2% at 1,500 ℃. In the proposed plant, even supposing that the generating efficiency of the LNG system in the proposed plant remains equal to that of the reference plant, the efficiency of LSCHG system can be estimated 37.4% for 6.5 MPa and 33.2% for 2.5 MPa, even though the LSHCG system may be regarded as consisting of fewer plant facilities than a conventional LSCHG power plant.

A preventive control strategy for static voltage stability based on an efficient power plant model of electric vehicles

With the increasing integration of wind farms and electric vehicles(EVs)in power systems,voltage stability is becoming more and more serious.Based on vehicle-to-grid(V2G),an efficient power plant model of EVs(E-EPP)was developed to estimate EV charging load with available corresponding response capacity under different charging strategies.A preventive control strategy based on E-EPP was proposed to maintain the static voltage stability margin(VSM)of power system above a predefined security level.Two control modes were used including the disconnection of EV charging load(‘V1G’mode)and the discharge of stored battery energy back to power grid(‘V2G’mode).A modified IEEE 14-bus system with high penetration of wind power and EVs was used to verify the effectiveness of preventive control strategy.Simulation results showed that the proposed strategy can not only improve the static voltage stability of power system with considerable wind generation,but also guarantee the travelling comfort for EV owners.

燃煤电厂CO_(2)捕集的减排效率研究与展望

为了客观评价不同CO_(2)捕集技术的能耗水平,判别CO_(2)捕集技术的有效性和经济性,提出减排效率概念和计算模型。CO_(2)减排效率表示某种CO_(2)捕集技术的有效减排能力,即捕集单位CO_(2)所发生的CO_(2)有效减排量,减排效率模型对CO_(2)捕集技术的能耗进行归集和平准化计算,其值越大表明减排效果越佳。利用减排效率模型测算,目前我国燃煤电厂CO_(2)捕集技术的减排效率理论极值为98%,燃烧前、燃烧中和燃烧后捕集技术的减排效率分别达到80%、70%和58%~68%。经工程应用实践验证,减排效率模型能满足评价要求。最后对CO_(2)捕集技术的发展进行了展望,认为未来随着捕集技术的不断进步和创新,CO_(2)减排效率将超过90%。

SCR烟气脱硝技术及脱硝效率影响因素研究

SCR脱硝技术是燃煤电厂烟气脱硝最常用的技术之一,为了提高燃煤电厂烟气脱硝效率,以某燃煤电厂的SCR烟气脱硝系统为研究对象,考察了不同类型催化剂、氨氮比、反应温度、二氧化硫质量浓度、氧气体积分数以及含水量等因素对脱硝效率的影响。结果表明,镍基分子筛类催化剂Ni/ZSM的脱硝效果相对更好,脱硝效率明显高于其他催化剂;随着氨氮比的升高,脱硝效率逐渐增大,而随着反应温度的升高以及氧气体积分数的逐渐增大,脱硝效率呈现先升高后降低的趋势;随着二氧化硫质量浓度和含水量的逐渐增大,脱硝效率逐渐降低。当选择Ni/ZSM作为催化剂,控制氨氮比为1.0,反应温度为300℃,氧气体积分数为5%,二氧化硫质量浓度和含水量均为0时,燃煤烟气的SCR脱硝效率可以达到87.1%,脱硝效率较高。

考虑能量效率和SOC均衡的电池储能电站双层功率分配策略

电化学储能电站在应用于调频、调压等功率波动性工况时,存在能量效率较低、荷电状态(state of charge,SOC)不均衡等问题。该文提出考虑能量效率和SOC均衡的电池储能电站双层功率分配策略,其主要包括单元优化层和子系统优化层:单元优化层通过充电/放电优先级分区计算实际运行单元数量及其编号,建立以储能单元能耗最小为目标的优化模型,并采用遗传算法求解最优解集;子系统优化层引入基于电化学阻抗的电池能耗模型,以储能子系统能耗最低和SOC均衡为目标建立多目标优化模型,并采用非支配快速排序遗传算法(non-dominated sorting genetic algorithms-II,NSGA-II)进行求解。通过某地区锂电池储能电站实际参数验证所提策略的有效性,结果表明,与SOC比例分配策略和单层功率分配策略相比,所提功率分配策略在降低电站能耗的同时能最大程度实现SOC均衡,保障电站双向调节能力,提高储能电站经济性。

基于NSGA-Ⅱ-VAR的燃煤电厂负荷预测

燃煤电厂负荷预测的意义在于可以预先了解未来一段时间内的电力需求情况,从而合理安排发电设备的运行和停机维修时间,避免能源浪费、提高发电效率;此外,在燃煤电厂参与深度调峰、配煤掺烧的大背景下,为了确保混煤发热量适应负荷需求,提高燃烧效率,需要提前预知未来一段时间的负荷。本文提出一种基于快速非支配排序遗传算法(nondominated sorting genetic algorithmⅡ,NSGA-Ⅱ)优化向量自回归模型(vector autoregression,VAR)的燃煤电厂负荷预测方法。该方法将历史过热蒸汽时间序列、历史再热蒸汽时间序列和历史发电量序列一起作为VAR模型的输入变量,预测未来8 h的发电负荷,同时使用NSGA-Ⅱ算法优化VAR模型的阶数和截距,从而提高了预测模型的精度。测试阶段,选取上海某机组2022年10月25日—2022年10月30日为数据样本区间,建立初始化预测模型;在2022年10月31日8:00—2022年11月1日16:00样本区间上测试模型效果,并使用NSGA-Ⅱ算法根据测试结果优化VAR模型;在2022年11月2日8:00—2022年11月3日16:00的样本区间上进一步测试优化后的模型预测精度。测试结果表明:预测均方根误差为15.341 MW,平均绝对误差为7.839 MW,和其他时序预测模型对比精度有所提高。该模型可实际运用于同类煤电机组的负荷预测,从而为后续运行决策提供参考。

Smart component monitoring system increases the efficiency of photovoltaic plants

Due to the increasing expansion of renewable energy,especially the widespread installation of solar power plants worldwide,to better exploit and increase the efficiency and quality of power generation,we need to closely monitor the performance of important components of the plant.In this study,using an innovative smart monitoring system and electronic sensors,we monitored compo-nents such as power in photovoltaic(PV)arrays in real time,including the phenomenon of hot spots as an example of power loss in PV panels.Detection of hot spots is very difficult to deal with in a large power plant.The results also demonstrated smart monitoring that increased detection speed and increased the efficiency rate per supervisory technician by≤36% compared with the previous ef-ficiency rate,which was 10% per technical staff,and increased the quality of the operation of each solar power plant.In this paper,meteorological data were coordinated with research data to validate the research.Furthermore,to compare the results of using the smart monitoring method with the conventional observation method,a complete diagram of a 5-kW solar system in MATLAB■2018 was simulated and output diagrams were presented.Finally,to provide a comprehensive validation,our research results were com-pared with technical data obtained from a local 5-kW solar power plant located in Sari,Iran(36°33ʹ48″N,53°03ʹ36″E)with an average annual irradiation of 1490 kWh/m^(2).When the simulation results and research are analysed,it is clear that the smart and real-time monitoring approach brings various benefits to solar power plants.

燃煤电厂袋式除尘器环保与节能耦合的性能优化研究

燃煤电厂袋式除尘系统在进行超低排放的过程中会消耗大量能源,为了使除尘器在满足出口烟气浓度排放指标的情况下以最优能耗的状态运行,收集燃煤电厂运行期间的监测数据,通过对除尘系统中涉及到能量的消耗及组成进行分析,建立单位质量除尘能耗指标模型和除尘效率指标,并研究灰分、燃煤热值和发电机组负荷率对除尘系统的影响规律。结果表明:除尘效率随灰分增加而提高,单位质量除尘能耗随灰分增加而减少并在灰分为18%时获得最佳能耗,燃煤热值的增加会使单位质量除尘能耗整体上升,但除尘系统在高热值区间运行较为稳定,机组负荷率在中高区间时,单位质量除尘能耗几乎没有变化,但设备能耗随负荷率的增加而线性增大,当机组超负荷时,最佳单位质量除尘能耗值会大幅上升,使得系统工作效益较低。

基于智能算法的发电系统运行能效分析

阐述智能算法在节能中的应用,包括能源管理领域的应用现状、在电厂节能管理中的运行能效。引入机器学习和深度学习算法,优化能源利用的模型。实验表明该算法的有效性。

煤电二氧化碳捕集能量梯级利用与机组效率分析

燃煤电厂配置二氧化碳捕集系统需消耗大量蒸汽用于吸收剂再生与循环利用,蒸汽消耗降低机组发电效率和发电量。机组热力系统和二氧化碳捕集系统的跨界区能量耦合利用是减少发电效率损失的重要途径。以全容量二氧化碳捕集的630 MW机组为对象,构建全容量烟气的二氧化碳捕集系统模型和汽轮机组热力系统热平衡图,借助等效焓降法研究碳捕集系统工艺参数选择及多种余热利用方法对汽轮机组发电效率的影响。结果表明:全容量二氧化碳捕集系统后需消耗569.18 t/h蒸汽,导致原机组循环效率从43.84%降至35.74%。再沸器凝结水余热用于富液加热时,再生热耗降低0.2 GJ/t,节约蒸汽用量43.05 t/h,机组循环效率升至36.35%,和余热用于机组回热系统效果相当,但前者系统更简单。再生气余热和二氧化碳压缩机级间余热可用于机组凝结水加热,节约机组低压缸抽汽,提高循环效率;再生气温度、流量和余热量与碳捕集系统富液分流工艺的分流比有关,随着冷富液流量增加,碳捕集系统能耗和机组发电效率损失均呈先降低再升高趋势,当冷富液、主富液、凝结水加热富液质量比0.20∶0.75∶0.05时,机组发电效率最高;二氧化碳压缩机级数越少可利用的热量越大,机组发电效率越高,但同时消耗更多电能。通过优化,配置全容量二氧化碳捕集系统的630 MW机组发电功率由无优化时的510.09 MW增至528.96 MW。

1000MW超超临界汽轮机组中低负荷节能研究

为解决中低负荷工况下的高耗能问题,某电厂进行了广义变频改造,并选取改造后的THA、75%THA和50%THA等3个典型工况进行了节能效果测试与研究。结果显示,在高负荷工况下,广义变频的节能效果并不显著;而在中低负荷工况下,广义变频的节能效果随着负荷的降低而增加。该研究表明,通过广义变频改造能够有效降低中低负荷工况下的能耗,同时该研究为AGC调频技术在深化节能改造方面的应用探索了道路。