低压加热器疏水方式改造对机组热经济性的影响研究

低压加热器疏水方式不同对机组的热经济性影响不同。以某电厂600MW机组低压加热器疏水系统为研究对象,通过分析原有疏水系统对机组热经济性的影响,提出了几种相应的改造方案。利用循环函数法对不同方案的热经济性进行了计算和比较,得出了最佳改造方案,为低压疏水系统热经济性分析和节能改造提供了依据。     

热力系统低压加热器不同疏水方式热经济性分析

火电厂热力系统中低压加热器疏水方式的不同会对机组的热经济性产生很大影响。以某电厂300MW机组低压加热系统为研究对象,通过等效焓降的方法,计算出几种改进方案下机组的循环效率、热耗率及煤耗率。通过比较几种方案下的热经济性得出最佳方案,为低压加热器疏水系统的热经济性和节能改造提供了一定的数据支持。     

EPR核电机组低压加热器疏水经济性分析

核电厂热力系统疏水回收方式对机组经济性有较大影响。通过热平衡法计算比较低压加热器三种疏水回收方式下机组的功率差异,分析1700 MW级核电机组采用三种不同低压加热器疏水回收方案的经济性与技术合理性,为汽轮机的选型及热力系统的节能改造提供数据支持。     

基于EBSILON的AP1000核电机组低加疏水系统研究

通过对AP1000核电机组二回路低压加热器(简称低加)疏水系统的研究,提出了11种不同的疏水布置方案,并通过EBSILON平台进行仿真计算,对不同疏水方案下机组的热经济性进行比较、分析。综合考虑系统热经济性及安全性,认为优选在3号低加设置疏水泵的方案,供电热耗可降低33. 33kJ/(k W·h)。     

1000MW机组低压加热器疏水系统的经济性研究

通过对1000MW超超临界火力发电机组的低压加热器疏水系统的研究,针对性地提出了3种不同的布置方式。运用热量法对其进行热经济性的理论分析与计算,结合机组的实际运行情况,对各个方案展开比较论证。认为6号低加采用疏水泵向前打,7号、8号低加使用外置式疏水冷却器的疏水连接方式热经济性较好,安全可靠,设计合理。     

热力系统疏水回收利用方式对机组热经济性的定量分析

热力系统疏水回收利用方式对机组的热经济性有很大的影响。使用疏水冷却器,可以降低疏水温度达到回收疏水的热量的目的;而疏水泵则因其能够截流疏水而达到接近混合式加热器的抽汽热量利用效果。本文通过热平衡法和等效热降法对不同疏水回收利方式的热效率进行了计算比较,为热力系统的节能改造提供定量数据支持。并以热平衡法为基准,对等效热降法的计算误差进行了分析。     

630 MW机组低压加热器疏水不畅原因分析及处理

某电厂2号机组存在6~#低压加热器疏水不畅问题。通过详细分析和现场检查,指出造成疏水不畅的主要原因是DCS水位准确度不高、疏水管道阻力设计缺陷以及低加疏水系统存在漏点。提出切实可行的处理方案,旨在解决机组低压加热器疏水不畅的问题,提高机组抽气回热系统循环热效率和机组运行经济性。     

某厂1000MW机组低压加热器疏水不畅分析与治理

为了解决某厂1 000 MW机组5至8号低压加热器正常疏水不畅,无法满足机组正常调整需要。机组正常运行时通过调整低压加热器危急疏水阀来调整低压加热器水位,大量高参数疏水通过危急疏水阀直接排入凝汽器,热量损失较大。通过调整低压加热器正常疏水阀通流面积以及优化疏水管路、消除管路水封,彻底解决了低压加热器疏水不畅问题,提高了机组经济性,降低了凝汽器热负荷。改造后,机组正常运行时,危急疏水阀全关,仅通过正常疏水调整即可满足要求,节能效果显著,且改造费用低,方案简单可行,供相关专业人员参考。     

采用喷射泵疏水方式的回热系统热经济性分析

介绍了目前凝汽式汽轮机组回热系统的基本疏水方式,分析了其优缺点。介绍了喷射泵的工作原理,建立了喷射泵工作流体流量的计算模型。提出了采用喷射泵的回热系统疏水方式,拟定了采用喷射泵疏水方式后机组的原则性回热系统简图。基于常规热平衡法,确定了喷射泵出口混合焓,并建立了机组热经济性指标的计算模型。以某300MW机组为例,计算了喷射泵的喷射系数,并对采用不同疏水方式机组的热经济性进行了比较。结果表明,采用喷射泵疏水方式机组的热经济性明显高于采用逐级自流疏水方式机组的热经济性。     

高位布置汽轮发电机组回热系统疏水方式优化与热经济性比较

由于布置的局限,全高位布置的汽轮发电机组回热系统可能出现上一级加热器的布置位置明显低于下一级加热器的情况,若采取常规的疏水逐级自流方式,极易出现疏水不畅、汽化,引起疏水管道振动等问题.为确保该类机组的经济、安全运行,提出了多种优化方案,并从可行性、热经济性、安全性对其进行了比较和分析,选出了最优方案.     

200MW机组三段卧式高压加热器设计

目前国内市场200MW机组高压加热器都是立式结构,一般需要蒸气冷却器、疏水冷却器独立设置,增加了设备数量及设计制造成本,整个系统布置运行控制也较复杂,本文主要介绍200MW机组高加采用卧式布置的技术特点.     

抽汽压损对机组热经济性影响的通用计算模型

经过严格的数学推导，证明了抽汽压损对热经济性的影响等同于抽汽压损引起的加热器出口水焓和疏水焓变化对热经济性影响的线性叠加。根据热力系统热经济性分析的基本方程，针对不同型式的加热器，计算了疏水焓对汽轮机作功量和锅炉吸热量的影响。得出了分析疏水焓变化对热经济性影响的通用计算模型。结合已建立的加热器出口水焓对热经济性影响的通用计算模型，推导了抽汽压损对机组热经济性影响的通用计算模型。该模型具有通用性强，适于程序化的特点。算例验证了该方法的正确性。     

Thermoeconomics of seasonal latent heat storage system

A simple thermoeconomic analysis is performed for a seasonal latent heat storage system for heating a greenhouse. The system consists of three units that are a set of 18 packed‐bed solar air heaters, a latent heat storage tank with 6000 kg of technical grade paraffin wax as phase‐changing material, and a greenhouse of 180 m². The cost rate balance for the output of a unit is used to estimate the specific cost of exergy for a yearly operation. Based on the cost rate of exergy, fixed capital investment, operating cost, and economic data, approximate cash‐flow diagrams have been prepared. The systems feasibility depends on the cost rate of exergy, operating cost, internal interest rate, and rate of taxation strongly. A cash‐flow diagram based on exergy considerations may enhance the impact of thermoeconomic analysis in feasibility studies of thermal systems. Copyright © 2006 John Wiley & Sons, Ltd.     

加热器端差对机组热经济性影响的定量分析方法

建立了定流量下加热器端差对机组热经济性影响的数学模型。该模型针对加热器的不同类型进行了讨论,应用时不再需要单独计算端差变化对锅炉吸热量的影响,并全面考虑了热力系统的结构特点及辅助汽水系统,从整体上定量分析加热器端差对机组热经济性的影响,为火电机组节能降耗以及热力系统定量分析提供了理论依据。对某600MW机组进行了算例分析,表明端差越大,机组的热经济性越低;端差越小,机组的热经济性越高。     

Cost structure of CGAM cogeneration system

The cost structure of the CGAM system, a predefined cogeneration system suggested to unify the different methodologies of thermoeconomic analysis, was investigated by using a thermoeconomic method called modified productive structure analysis (MOPSA). An emphasis has been specially put on how the cost structure of the system is affected by the chosen level of aggregation that specifies the subsystems. It has been found that the unit cost of products is dependent on the chosen level of aggregation of the system only when one considers the entropy flow as one of the parameters to determine the unit cost of products. Copyright © 2004 John Wiley & Sons, Ltd.     

基于分析法抽汽压损对煤耗率的影响

根据热经济性指标和的物理意义,定义锅炉效率、机组效率、发电煤耗率的数学计算式;由小扰动理论和微分理论,当抽汽压损变化时,在热力系统汽水分布方程的基础上详细推导抽汽量变化与不同类型加热器出口水焓与疏水焓的微分关系式;根据锅炉效率、机组效率、发电煤耗率的数学计算式,推导锅炉效率、机组效率、发电煤耗率变化与抽汽量的微分关系式。结合N1000-25/600/600机组,定量分析抽汽压损变化对锅炉效率、机组效率、发电煤耗率的影响,为有效分析机组经济性提供理论依据。     

基于超音速激波升压装置的回热系统的热经济性分析

本文通过超音速激波升压装置替代常规的加热器，建立了超音速激波升压回热系统。在此替代基础上，用等效热降理论分析了替代机组的热经济性变化情况，建立了替代机组热经济性变化的通用计算数学公式。实例计算结果表明通过超音速激波升压装置替代常规加热器，可以在较大程度上提高火电厂的热经济性。     

Exergo‐economic analysis of micro pin fin heat sinks

A parametric study of thermoeconomic performance over four micro pin fin heat sinks of different spacing and shapes was conducted. Unit cost per product exergy, relative cost difference, and exergo‐economic factor were utilized to evaluate the thermoeconomic performance. The effect of working fluid on the thermoeconomic performance was also investigated using R‐123 and water as working fluids. Unit costs per product exergy were obtained to evaluate the product costs (total exergy change between exit and inlet streams) in micro pin fin heat sinks at fixed mass flow rate and fixed pressure drop. The results of the thermoeconomic analysis were compared with the results of a past exergy performance study by the author. In the light of raw experimental data acquired from the past studies of the author, important differences between the results of exergy and exergo‐economic performances were observed. It was found that the unit cost of exergy change decreased as electrical power increased and the relative cost difference approached to unity at high electrical powers (greater than 20 W). Moreover, high exergo‐economic factor values (more than 0.5) were obtained at low electrical powers while exergo‐economic factors had a small value at high electrical powers. When looking at the effect of the working fluid, higher cost per Watts of the products (up to the double of R‐123) was obtained with water compared with R‐123 at both fixed mass flow rate and pressure drop. No significant effect of pin fin spacing on the unit cost of exergy change was observed at fixed mass flow rate, while higher unit costs (up to 102%) were recorded at fixed pressure drop for scarcely packed pin fin heat sinks. Finally, the unit cost of exergy change was found to be independent of pin fin shape at fixed mass flow rate, whereas at fixed pressure drop, the hydrofoil‐based pin fin heat sink had higher unit costs (up to 1.8 times as much) when compared with the unit costs of pin fin heat sinks having flow separation promoting pin fins. Copyright © 2010 John Wiley & Sons, Ltd.     

某2×660MW机组低压加热器异常振动的分析与处理

汽轮发电机组低压加热器的振动现象是火电厂中常见的问题。某2×660MW火电基建机组在整套调试期间,低压加热器、管道及阀门等相关设备发生强烈的异常振动现象。强烈的异常振动会严重影响低压加热器、管道及阀门等相关设备的安全运行和使用寿命。针对某2×660MW机组低压加热器等相关设备的异常振动现象,介绍了低加异常振动现象出现的经过,分析了异常振动产生的原因,并提出了相应的解决措施与处理建议。