SCAL型间接空冷循环水系统腐蚀原因分析与对策

SCAL型间接空冷机组循环水系统充水后1050A纯铝散热器易发生大面积腐蚀,分析故障原因为散热三角底部碳钢膨胀节(哈夫法兰)-1050A纯铝散热器发生了电偶腐蚀。提出了降低电偶腐蚀程度的解决方案,通过从结构上切断1050A纯铝散热三角与碳钢膨胀节(哈夫法兰)的电子通路、最小化电偶腐蚀阴极面积,在循环水中添加防腐缓蚀剂等措施,可以将1050A纯铝的腐蚀速率控制在小于0.005 mm/a的水平,碳钢与不锈钢的腐蚀速率也低于国家有关标准的要求。     

SCAL型间冷系统散热器铝管端口腐蚀原因分析

某电厂SCAL型间冷系统散热器铝管端口发生了严重腐蚀,从设备结构特点、流场分布、损坏部位形貌、循环水中悬浮物成分来源等方面对管件腐蚀机理进行了分析;认为循环水对铝管的冲刷破坏了铝表面的氧化膜,在电化学腐蚀与颗粒物冲刷腐蚀的相互促进作用下,对散热器铝管端口部位造成腐蚀破坏;并给出了在铝管端口增加尼龙套管、改进铝管和集水箱结合处的密封垫圈等防腐蚀建议。     

SCAL型间接空冷系统防冻研究

基于国内多个间接空冷电厂在实际运行中遇到的防冻问题,从设备选型、控制系统及实际运行等方面分析了空冷散热器管内发生冰冻现象的原因。结合我国“三北”地区的气象特点,提出可供SCAL型间接空冷系统采用的设计和运行方面的防冻措施,为SCAL型间接空冷系统在“三北”地区的应用提供了防冻技术支持。     

SCAL型间接空冷系统防冻研究

基于国内多个间接空冷电厂在实际运行中遇到的防冻问题,从设备选型、控制系统及实际运行等方面分析了空冷散热器管内发生冰冻现象的原因。结合我国"三北"地区的气象特点,提出可供SCAL型间接空冷系统采用的设计和运行方面的防冻措施,为SCAL型间接空冷系统在"三北"地区的应用提供了防冻技术支持。     

间接空冷换热器铝管束腐蚀原因分析及解决措施

内蒙古京能康巴什热电有限公司间接空冷系统在投运初期,由于循环水pH值升高,2台机组间接空冷系统272个冷却三角管束在底部管箱与管板接口处均发生局部腐蚀并泄漏。对泄漏的管束进行检查,分析出铝管腐蚀的原因,提出了不吊装冷却三角、对局部腐蚀管束的腐蚀部位加装衬管的方案,并自行设计了小阳床装置,安装在主机间冷塔内,有效控制了循环水的p H值,保证了机组的正常稳定运行。     

SCAL型间冷系统循环废水回收处理

SCAL型间冷系统的循环废水中含有大量铁铝腐蚀产物,根据间冷循环水的水质特点,通过理论分析拟定了回收方案,通过工业实验对其进行了验证。结果表明,实施回收前需要对废水的温度、pH值、浊度和铁铝含量进行测定,当循环废水的水质指标不能满足水处理设备进水要求时,需要按照一定的比例将间冷循环废水和厂区生水在生水箱中混合后再进行回收处理。     

SCAL型间接空冷循环水复合防腐处理研究

哈蒙式间接空冷机组在运行过程中,循环水由于多种原因易导致冷却三角腐蚀甚至引起机组停机,为了较好地控制间接空冷循环水的水质,采用旁路混床及联氨加药联合处理,使得间冷循环水的电导率不高于5μs/cm、pH趋于中性,此方法克服了旁路阳床不能去除阴离子、无法持续运行及需要配置再生系统的弊端,具有环保、节约、经济的优势。     

SCAL型间接空冷系统设计参数的优化

本文根据多个SCAL型间接空冷系统的工程设计,分析了ITD、迎面风速、散热器高度、塔形尺寸等设计参数对空冷系统规模的影响。比较了煤价、成本电价对空冷电厂年总费用的影响。衡量了环境风及“三塔合一”中脱硫岛布置对空冷系统换热性能的影响。提出了指导SCAL型间接空冷系统设计参数优化的原则。     

对表面凝汽式间接空冷系统冬季防冻的探讨

针对冬季运行工况下表面凝汽式间接空冷系统冻结损坏问题,从散热器基管堵塞、循环水质、操作方式等方面分析原因,采取循环水管道清淤和冲洗、散热器易泄漏部位加装防冻挡风板和补水泵入口加装过滤网等方法进行改造,提出了有效的防范措施。改造结果表明:空冷系统散热器泄漏率下降了92%,保证了机组运行的安全性和经济性,提高了供热可靠性。     

间接空冷机组循环水联氨处理工艺的电化学研究

利用电化学阻抗谱、电化学噪声测试技术和动电位扫描极化曲线方法研究了间接空冷机组循环水联氨处理工艺的电化学机理。研究结果表明,联氨处理工艺能够实现腐蚀体系的电化学状态重建,使原先处于阳极状态发生腐蚀的1050A纯铝转变为处于电化学状态重建腐蚀体系的阴极状态;联氨可以作为1050A纯铝的阴极型缓蚀剂、碳钢的阳极型缓蚀剂,以及1050A纯铝—碳钢电偶腐蚀的缓蚀剂。间接空冷机组循环水系统采用联氨处理工艺能够有效地降低1050A纯铝的均匀腐蚀和1050A纯铝—碳钢电偶腐蚀的腐蚀速率,可以保证碳钢与不锈钢的腐蚀速率满足国家标准的要求。     

Decentralized indirect adaptive control of interconnected systems

Continuous time decentralized indirect adaptive controllers are proposed for a large-scale system composed of N interconnected linear subsystems with unknown parameters. Each local adaptive law utilizes a normalizing signal which is generated using the local input and the outputs of all the subsystems. This requires the exchange of output signals between the different subsystems, so that the scheme is no longer totally decentralized. Nevertheless, the degree of computational complexity is about the same as that of a totally decentralized scheme and this makes the scheme very attractive.     

Robust pole placement indirect adaptive control

The problem of designing a robustly stable pole placement indirect adaptive controller in the presence of output disturbances and unmodelled dynamics is addressed. The key features of such a design are the following. (1) The unknown parameters are estimated by a normalized least-squares algorithm with a dead zone to provide the stability robustness with respect to bounded disturbances and ‘small’ unmodelled dynamics. (2) The estimated model controllability is ensured by modifying the control law over a finite time. The modification involved consists of adding an internal impulse excitation and ‘freezing’ the controller parameters.     

一种间接的LED结温测量的方法

通过对LED(发光二极管)工作原理分析,提出了将测量难度很高的温度变量转化为测量难度相对较低的电压变量,并且结合LED在实际应用中的情况,实现了LED结温的精确测量.     

Real-time implementation of an indirect adaptive robot controller

Adaptive controllers applied to high-speed and high-precision robot manipulators give excellent tracking performances because they take into account the full dynamics of the robot. Recent publications have shown that on-line estimation of the dynamic constant parameters can be obtained by the joint tracking error (direct adaptive control) or by the torque prediction error (indirect adaptive control). In direct adaptive controllers the estimation law is derived from Lyapunov stability or Popov hyperstability methods. These controllers are simple and their real-time implementation is easy; however, the estimation is not so accurate. In indirect adaptive controllers the estimation law is based on a least squares algorithm. These controllers give accurate estimates of the manipulator parameters; however, they involve much more computation than the direct approach. Therefore no real-time implementations of indirect adaptive tracking controllers for robots have been reported in the literature until now. This paper describes a real-time implementation of an indirect adaptive scheme applied to a two-degree-of-freedom (2DOF) direct-drive SCAM robot. the controller is implemented at low cost by the use of a single-chip digital signal processor (DSP).     

Precedence relationship performance of an indirect matrix solver

A highly parallel truncated accelerated Neuman series preconditioner is presented. Results from using this preconditioner are compared with those obtained using a traditional truncated Neumann series preconditioner and the Jacobi method on matrices whose numerical content is characteristic of the bus admittance matrices used in the analysis of faulted power system problems. These results show that the number of precedence relationships experienced by this technique are of the same order of magnitude as the number encountered when using direct methods     

Slip-frequency detection for indirect field-oriented control drives

This paper presents a new technique to detect the slip angular frequency in induction motor drives with indirect field-oriented control (IFOC). Slip frequency is calculated by processing the effects exerted by an additional high-frequency signal on the zero-sequence stator voltage. By measuring such a zero-sequence voltage, it is possible to evaluate the air-gap flux and detect the slip frequency in order to implement an IFOC algorithm. According to the proposed approach, rotor time constant errors are not influent as in conventional field-oriented control schemes, thus, complex tuning or compensation techniques are not required. Simulations and experimental tests are performed to evaluate the consistency of the proposed approach.     

基于间接电流控制的并网逆变器

提出了一种用于并网逆变器的间接电流控制新方法.该方法是在状态平均法的基础上对并网逆变器工作时的基本模态进行分析,推导出实现单位功率因数并网的占空比的控制函数,从而通过控制可调占空比对并网逆变器的输出电流进行控制.该方法的特点是控制电路中只有2个电压回路来调整可调占空比,由于没有电流检测回路,省去了工频变压器和电流互感器,使得控制结构简单,控制成本低:仿真结果表明,与其他传统的PwM控制方式相比,该方法具有抗干扰能力强、开关损耗小、输出电压的谐波畸变率小等优点.     

An indirect adaptive fuzzy-logic power system stabiliser

An indirect adaptive fuzzy power system stabiliser (AFPSS) is developed using the concept of fuzzy basis functions. The power system is modelled using differential equations with nonlinear parameters which are functions of the state of the system. These nonlinear functions may not be known, however, some linguistic information is available about them. Utilising this information, fuzzy logic systems are designed to model the system behaviour. The control law is obtained using the uncertainty principle. Based on the Lyapunov's synthesis method, adaptation rules are developed to make the controller adaptive to changes in operating conditions of the power system. The simulation studies are carried out for an industrial cogenerator and utilise a one-machine infinite-bus model. Nonlinear simulations reveal that the performance of AFPSS is better than the performance of a conventional (linear) power system stabiliser for a wide range of operating conditions.     

细粉分离器效率间接测算

电站锅炉细粉分离器效率测试通常采用直接测试方法.但该方法相对复杂,其准确性受天气、管道布置、测量位置等客观因素的影响.提出一种通过测量制粉系统投退前后锅炉热负荷的变化来间接测算细粉分离器效率的方法,该方法在巴陵石化热电事业部4号炉上进行了应用,结果表明该方法简单可行,其测算结果与标准推荐方法测试结果相近.     

Development of indirect internal reforming molten carbonate fuel cell

Molten carbonate fuel cell (MCFC) has high potential for use as an energy converter of various fuels to electricity and heat. MCFC causes the environmental pollution and helps to reduce the greenhouse problem. The development of an indirect internal reforming molten carbonate fuel cell (IIR-MCFC) was initiated by the Kansai Electric Power Company and Mitsubishi Electric Corporation. IIR-MCFC has several advantages, for example: (1) higher efficiency is expected because of efficient utilization of heat from cell reaction to reforming reaction; and (2) longer life compared with direct internal reforming MCFC is expected by means of loading reforming catalyst in the cell separated from the electrolyte vapor which causes deactivation of the reforming catalyst. Class stacks of 3 kW, 10 kW, 30 kW and a 100 kW were operated successfully. Output power of the 100-kW class stack generated 109 kW in IIR mode (direct methane feed). In the test of the 30-kW and the 100-kW class stacks, PSA (pressure swing adsorption) to separate carbon from the anode exhaust gas is installed in the anode gas recycle loop to the cathode.