太阳能与燃煤机组集成发电系统性能研究

以常规燃煤机组为原型,提出新的槽式太阳能与燃煤机组集成发电方式,即槽式太阳能集热场加热小汽轮机排汽,取代部分1号高压加热器回热抽汽。利用模拟软件建立发电系统计算模型,分析太阳能辐射强度（DNI）和集热面积对该系统性能的影响。以动态投资回收期TDP、内部收益率IRR等为评价指标,对该系统进行经济性分析。结果表明：随着太阳能幅射强度的增大,互补发电系统的太阳能发电功率、太阳能热电转换率等随之增大,且集热面积的影响趋势与太阳能幅射强度（DNI）大致相同;在拉萨地区进行该系统建设的IRR最高,为16.97%;对IRR的敏感性影响因素从大到小排序依次为煤炭价格、集热器造价和并网电价。     

太阳能与燃煤机组混合发电方式的热经济性研究

阐述了分别从锅炉蒸发受热面、高压加热器汽侧和汽轮机低压缸引入太阳热能与燃煤机组进行混合发电的3种集成方案,定义了太阳能热电转换率、单位时间节煤量及太阳能热贡献率等评价指标,并以某300 MW燃煤机组为例,应用变热量等效焓降法计算理论对3种太阳能与燃煤机组混合发电集成方案的热经济性指标进行了计算和比较,确定了混合发电的最优集成方式,并对其经济性进行了初步分析.结果表明：混合发电集成方案2-1（取代2号高压加热器抽汽）的热经济性指标、运行安全性和稳定性均较好,因此选取方案2-1作为混合发电最优集成方案;太阳能的单位发电成本为0.63元/（kW·h）,低于单纯太阳能发电站的0.75～1.85元/（kW·h）.     

CO2减排机理及与燃煤电厂集成特性的研究

推导了CO2吸收工艺系统再生能耗计算公式,分析了吸收剂性质对再生能耗的影响,计算得到不同质量分数下吸收剂的再生能耗;提出几种基于槽式太阳能辅助燃煤发电技术的CO2减排集成方案,以N600-24.2/566/566型发电机组为例,以集成系统热耗率、发电标准煤耗率和热效率作为经济性指标,采用热平衡法对不同集成方案机组的热经济性指标进行了计算和比较.结果表明:在加入太阳能热量和机组主蒸汽质量流量不变的情况下,集成方案5在设计辐照强度下的热耗率和发电标准煤耗率均最低,是最经济的集成方案.     

CO_2减排机理及与燃煤电厂集成特性的研究

推导了CO2吸收工艺系统再生能耗计算公式,分析了吸收剂性质对再生能耗的影响,计算得到不同质量分数下吸收剂的再生能耗;提出几种基于槽式太阳能辅助燃煤发电技术的CO2减排集成方案,以N600-24.2/566/566型发电机组为例,以集成系统热耗率、发电标准煤耗率和热效率作为经济性指标,采用热平衡法对不同集成方案机组的热经济性指标进行了计算和比较.结果表明:在加入太阳能热量和机组主蒸汽质量流量不变的情况下,集成方案5在设计辐照强度下的热耗率和发电标准煤耗率均最低,是最经济的集成方案.     

太阳能与燃煤联合发电技术及其应用前景

介绍了太阳能与燃煤联合发电技术原理及工程应用,综合分析了联合发电系统不同集成方案的热经济性,给出了太阳能与燃煤联合发电技术的应用前景,提出了我国发展太阳能与燃煤联合发电技术的建议。通过对太阳能与燃煤联合发电系统的性能分析及工程实例表明,太阳能场与燃煤机组回热系统相结合的方式,运行稳定,经济性较好,特别是太阳能场取代1段抽汽的集成方案较为理想,具有很好的发展前景。     

太阳能集热系统与600MW燃煤机组集成及性能分析

为了避免工质两相流带来传热效果的恶化和流体分层现象,提出了抛物面槽式太阳能集热器与600 MW燃煤机组热力系统集成的优化设计。以呼和浩特地区为例,针对600 MW机组最优集成方案的研究结果表明,取代2段抽汽方案为最优,其太阳能热电转换率达35.85%,全年可节约标煤12 494.09 t,减排二氧化碳29 610.99 t,投资回收期为12.5 a。     

太阳能集热器与燃煤机组回热系统耦合的性能研究

提出了利用LS-3型抛物面槽式太阳能集热器对燃煤机组凝结水或给水进行辅助加热的两种集成方案,分别对N300-16.67/537/537,N600-24.2/566/566,N1000-25/600/600等3种不同型号的机组进行经济性能评价。研究结果表明:与大容量机组相比,小容量燃煤机组的投资节煤比较大,节煤量较大,投资成本较小;集成系统热经济性随太阳能集热系统辅助加热的凝结水(给水)流量比率的增大而提高,投资节煤比则相反;用太阳能集热器加热给水泵出口到省煤器入口的水,对改善机组热经济性和降低投资成本有利;在太阳能辐射强度1 000 W/m2的情况下,N300-16.67/537/537型机组的流量比率为5%时,节煤率为3.29 g/kWh。     

太阳能-锅炉联合中温蒸汽系统设计与TRNSYS模拟

针对广州某纺织厂设计一套1 t/h热负荷的太阳能-锅炉联合蒸汽系统,建立系统的热力学模型和基于TRNSYS软件的仿真模型,并以太阳指数、集热效率及太阳能保证率等参数为指标对系统进行模拟研究。结果表明:所设计的系统及控制方式在不同时刻所产生的蒸汽量可以满足负荷需求;系统月均太阳指数最高为38%,全年月均集热效率最高为43%,11月份太阳能保证率最高为26%,该系统每年可减少CO₂排放量235 t,节省天然气12万m³,相当于节约160 t标准煤,具有良好的经济和环保效益。     

太阳能与燃煤机组混合发电系统集成方式的研究

阐述了太阳能与燃煤机组混合发电系统的3种集成方式:太阳能集热场与锅炉并联,太阳能集热场与加热器并联及太阳能集热场与锅炉、加热器二者并联.采用传统的绝对电效率、标准煤耗以及太阳能热发电效率作为经济性指标,并利用热平衡方法对混合系统的热经济性指标进行了计算.以200 MW机组热力系统为例,对3种集成方式下机组的热经济性指标进行了比较,对不同辐射强度下机组热经济性指标的变化规律进行了分析,并确定混合发电的最优集成方式.结果表明:太阳能与燃煤机组混合发电时,太阳能热发电效率高于单纯的太阳能热发电,且燃煤机组煤耗率降低;在3种集成方式中,太阳能集热场与锅炉并联时,太阳能热效率最高、节煤量最多.     

太阳能辅助燃煤热发电系统的探讨

由于太阳能供给的间歇性,单独投资建造的太阳能热发电系统经常会出现设备成本高、利用率低、收益低等问题。因此,利用太阳能热发电系统与常规燃煤发电系统都有汽轮机部分这一特点,将槽式抛物太阳能集热器集成到常规燃煤发电系统中,寻求改造现有燃煤发电系统的新途径。以某300 MW机组为例,利用弗留格尔公式进行变工况计算,然后进行热经济性分析,为太阳能辅助燃煤热发电混合系统的建立提供理论参考。     

Experimental study on conventional solar still integrated with inclined solar still under different water depth

This study primarily focuses on comparative experimental analysis on standalone conventional solar still (CSS), inclined solar still (ISS), and integrated conventional and inclined solar still (CSS‐ISS) for different parameters that affect the freshwater yield. For enhancing the freshwater yield only a few studies are available on still‐still integration. The present novel study provides a greater improvement in improving the freshwater yield by integrating ISS with CSS. This experimental work mainly concentrates on the importance of water depth (d _w) and mass flow rate of water ( m _w) in the solar still. Water depth inside the conventional still varied from 0.02 to 0.06 m whereas, water is constantly flown with a mass flow rate of 8.33 kg/hour in an ISS with baffles. The experimental result shows that the accumulated freshwater yield from CSS‐ISS, ISS, and CSS were 6.2, 5.04, and 4.24 kg, respectively. CSS‐ISS and ISS produced 46.23% and 18.87% higher productivity than the CSS. From the experimental investigation, it is also identified that the water temperature is significantly improved by 20% using integration as compared with CSS without integration under the same water depth of d _w = 0.02 m. The overall improvement in yield was higher in the case of CSS‐ISS. The deviations between experimental and theoretical values of yield from the conventional and modified solar still were in the range of ±7%.     

Thermo-economic comparative analysis of solar-assisted and carbon capture integrated conventional cogeneration plant of power and process steam

A thermo-economic comparative analysis of steam production using a solar-assisted cogeneration (SACG) and a conventional cogeneration plant (CCG) with and without carbon capture systems has been conducted. The plants considered to produce electricity and process steam of 500 ton/h. Several parametric studies were carried out on the effect of natural gas price, steam quality, gas turbine capacity and solar multiples (SMs) on the Levelized cost of steam (LCS). Results show that in a CCG plant that comprises a 20 MWe gas turbine, the LCS is $8.11/ton of steam and $3.61/ton of steam from a plant with 100 MWe gas turbine capacity for a natural gas price of $3/GJ. The cost analysis of SACG plant with SM of 0.1 shows that 28% of the total annualized costs are solar system related while it contributed only about 9.17% of the annual steam generation. An increase in SM from 0.1 to 0.9 increases the CO₂ avoidance from 61 to 262 ktons/annum for the SACG plant with 20 MWe gas turbine. CCG plants with CO₂ capture technologies were found to have lower LCS in comparison with that of SACG plant. The impact of carbon credit implementation on the LCS has been also investigated and reported in this article.     

Design and analysis of a solar tower power plant integrated with thermal energy storage system for cogeneration

In the current study, a solar tower–based energy system integrated with a thermal energy storage option is offered to supply both the electricity and freshwater through distillation and reverse osmosis technologies. A high‐temperature thermal energy storage subsystem using molten salt is considered for the effective and efficient operation of the integrated system. The molten salt is heated up to 565°C through passing the solar tower. The thermal energy storage tanks are designed to store heat up to 12 hours. The temperature variations in the storage tanks are studied and compared accordingly for evaluation. The effect of operating temperatures on the freshwater production and overall system efficiency is determined. About 24.46 MW electricity is generated in the steam turbine under sunny conditions. Furthermore, the storage subsystem stores heat during sunny hours to utilize later in cloudy hours and night time. The produced power decreases to 20.17 MW in discharging hours due to temperature decrease in the tank. The electricity generated by the system is then used to produce freshwater through the reverse osmosis units and also to supply electricity for the residential use. A total flowrate of 240.02 kg/s freshwater is obtained by distillation and reverse osmosis subsystems.     

一种太阳能吸热器过热蒸汽温度控制系统

介绍了一种应用于塔式太阳能热发电系统的水/蒸汽吸热器过热蒸汽温度控制系统。受到太阳辐射能间歇性和不确定性的影响,吸热器产生的过热蒸汽温度难于控制。控制系统根据吸热器在蒸汽流量变化、光功率变化和减温水流量变化等3种主要扰动下的过热汽温度动态响应特性,以减温水流量作为控制量,光功率和蒸汽负荷作为前馈信号,设计和研制了两段式过热蒸汽温度控制系统,使吸热器过热区出口汽温维持在允许的范围内。     

Comparative performance investigation of integrated collector‐storage solar water heaters with various heat loss reduction strategies

A detailed comparative assessment is reported on the thermal performance of integrated collector‐storage (ICS) solar water heaters with various strategies for reducing top heat losses. The objective of this investigation is to assess and compare heat loss reduction strategies. The shape of ICS solar water heater considered in present investigation is rectangular. The thermal performance of the solar water heater is evaluated and analyzed for the following cases: (1) single glass cover without night insulation; (2) single glass cover with night insulation; (3) double glass cover without night insulation; (4) transparent insulation with single glass cover; and (5) insulating baffle plate with single glass cover. Energy balances are developed for each case and solved using a finite difference technique. The numerical assessment of the system performance is performed for a typical July day in Toronto. Each strategy is observed to be beneficial, reducing top heat losses, and improving system performance. The greatest performance enhancements are observed for the water heater with a single glass cover and night insulation and for the system with a double glass cover and without night insulation. Copyright © 2010 John Wiley & Sons, Ltd.     

Transient performance of direct steam generation solar power plants

Parabolic trough power plants are currently the most commercial systems for electricity generation. In this study, a transient numerical simulation of a solar power plant was developed by using direct steam generation (DSG) technology. In this system, condensate water from a Rankine cycle is pumped directly to solar parabolic trough collectors. The pressurized water is heated and evaporated before being superheated inside the solar collectors and directed back to the steam turbines, where the Rankine cycle is a reheated‐regenerative cycle. The plant performance with saturated steam production is compared with the performance of a superheated plant. A mathematical model of each system component is presented, with the solar power cycle modeled by the TRNSYS‐17 simulation program. Annual transient performance, including plant power and efficiency, is presented for both plants. As expected, the power of the superheated plant outperforms the saturated plant by approximately 45%, whereas the efficiency decreases by approximately 10%. Furthermore, the power of such plants is considerably improved under the weather of Makkah, 22.4°N, and it is approximately 40 MW for both the spring and autumn seasons. The annual generated energy is approximately 8062 MWh. The levelized electricity cost (LEC) was estimated for both the DSG and the corresponding synthetic oil plants. The DSG plant has an approximately 3% higher LEC than a synthetic oil plant with heat storage and an approximately 11.2% lower LEC than an oil plant if the plant has no storage. Copyright © 2016 John Wiley & Sons, Ltd.     

Conceptual design and techno-economic assessment of integrated solar combined cycle system with DSG technology

Direct steam generation (DSG) in parabolic trough collectors causes an increase to competitiveness of solar thermal power plants (STPP) by substitution of oil with direct steam generation that results in lower investment and operating costs. In this study the integrated solar combined cycle system with DSG technology is introduced and techno-economic assessment of this plant is reported compared with two conventional cases. Three considered cases are: an integrated solar combined cycle system with DSG technology (ISCCS-DSG), a solar electric generating system (SEGS), and an integrated solar combined cycle system with HTF (heat transfer fluid) technology (ISCCS-HTF).This study shows that levelized energy cost (LEC) for the ISCCS-DSG is lower than the two other cases due to reducing O&M costs and also due to increasing the heat to electricity net efficiency of the power plant. Among the three STPPs, SEGS has the lowest CO₂ emissions, but it will operate during daytime only.     

A modern injected steam gas turbine cogeneration system based on exergy concept

Factors such as low capital cost, good match of power and heat requirements and proven reliability can sometimes lead an end user into purchasing gas turbines for use in a modern cogeneration plant. The steam‐injected gas turbine is an attractive electrical generating technology for mitigating the impacts of rising energy prices. According to such mentioned above this paper is to provide results of an optimization study on cogeneration power cycle, which works by gas turbine with recuperator and injection steam added to the combustor of the gas turbine. The performance characteristics of the cycle based on energy and exergy concepts and based upon practical performance constraints were investigated. The effect of the recuperator on the cycle was greatly clarified. Results also show that the output power of a gas turbine increases when steam is injected. When extra steam has to be generated in order to be able to inject steam and at the same time to provide for a given heat demand, power generating efficiency increases but cogeneration efficiency decreases with the increasing of injected steam. Copyright © 2004 John Wiley & Sons, Ltd.     

Development of advanced solar assisted drying systems

The Solar Energy Research Group in the Universiti Kebangsaan Malaysia has been set-up more than two decades ago. One of the activities is in the field of solar thermal process, particularly in development of solar assisted drying systems. Solar drying systems technical development can proceed in two directions. Firstly simple, low power, short life, and comparatively low efficiency-drying system. Secondly, the development of high efficiency, high power, long life expensive solar drying system. The group has developed four solar assisted drying systems namely (a) the V-groove solar collector, (b) the double-pass solar collector with integrated storage system, (c) the solar assisted dehumidification system for medicinal herbs and (d) the photovoltaic thermal (PVT) collector system. The common problems associated with the intermittent nature of solar radiation and the low intensities of solar radiation in solar thermal systems can be remedied using these types of solar drying systems. These drying systems have the advantages of heat storage, auxiliary energy source, integrated structure control system and can be use for a wide range of agricultural produce.     

太阳能中高温热利用技术及其经济性分析

设计了一种太阳能中高温热利用系统,并对系统的经济性进行了分析。同时,以槽式太阳能热发电成本为依据,对系统的投资成本和投资回收期进行了计算和分析。结果表明,太阳能中高温热利用系统的建设投资成本有望降低到650美元/kW,总投资成本有望降低到750美元/kW。对于年日照时间在2000 h以上地区,随着系统规模的扩大,投资回收期5.6～12.5 a。综合显示,太阳能中高温热利用技术具有较好的经济性。