UDC6300在锅炉汽包水位调节中的应用

汽包水位是锅炉安全运行的重要指标。维持汽包水位在允许的范围内，是确保锅炉正常运行的必要条件。影响汽包水位变化的因素很多，其中主要是锅炉蒸发量、给水流量、炉膛热负荷、汽包压力等。由于它们的存在，汽包水位不断变化，而且容易产生“虚假水位”。为此，采用合理有效的控制措施是必要的。１ 汽包水位自动调节方案的选定 由于汽包水位的影响因素多，简单的调节系统不能保证水位的稳定，因而采用三冲量串级调节系统，其原理见图１。 该系统中，仪表选型为：调节器ＵＤＣ６３００（美国Ｈｏｎｅｙｗｅｌｌ公司产品）；水位变送器１１…     

锅炉汽包水位串级三冲量PID控制系统的设计

本论文结合火电厂锅炉汽包水位运行状况,对锅炉汽包给水调节系统运行优化进行了深入设计和研究,得出了以下成果:针对汽包锅炉给水控制系统,提出了控制系统设计原则和要求,将串级三冲量PID控制技术应用到给水控制系统,提高给水调节系统的可靠性。     

循环流化床锅炉汽包液位控制系统的改进

汽包水位调节是循环流化床锅炉自控系统中非常重要的一个调节系统,锅炉中汽包水位高度是确保安全生产和提供优质蒸汽的重要参数。我公司JG-35/3.82-M型35 t/h循环流化床锅炉汽包水位调节采用的是汽包水位、给水流量和主蒸汽流量串级三冲量调节方式。     

KMM可编程调节器及其应用 第六讲 KMM可编程调节器的应用举例

1 汽包水位单冲量/三冲量自动调节图6—1为某大型合成氨装置采用模拟仪表构成的辅助锅炉汽包水位自动调节系统。系统中配置有一台液位调节器(LIC-1)、一台锅炉给水调节器(BFWC—1)、一台加减器(RL—7)及一个单冲量/三冲量切换开关等硬件。它既可以实现单冲量调     

锅炉汽包水位测量与控制

文章介绍了锅炉汽包水位的测量方法,单冲量及三冲量控制方案的特点及需注意的问题。汽包水位是锅炉运行中的一个重要的安全性监控参数,保证汽包水位正常是保证锅炉和汽轮机安全运行的必要条件。水位过高会破坏汽水分离装置的正常工作,导致蒸汽带水,造成受热面积结垢,严重时会导致汽轮机水冲击振动、叶片损坏;水位过低会破坏水循环,引起下降管带汽,影响水循环工况,造成水冷壁管烧坏,甚至引起锅炉爆炸事故。将汽包水位控制在一定范围内是锅炉安全稳定运行的基础。     

锅炉汽包液位控制系统与连锁保护设计

汽包水位是工业锅炉安全、稳定运行的重要指标,汽包水位控制通过计算机控制对锅炉的自动检测、自动控制、自动诊断,实现集中监控和操作。通过分析锅炉的自动控制系统的工作原理,按照工程设计的具体步骤,设计了锅炉汽包液位控制系统的电气连锁保护,采用三冲量水位控制系统,以锅炉水位为主控信号,蒸汽流量为前馈信号,给水流量为控制器的反馈信号。通过PID控制,使锅炉水位维持在正常的范围内,当水位超限,能及时报警并采取措施。     

浅谈水泥窑余热锅炉汽包水位三冲量控制系统

汽包水位是表征余热锅炉运行的重要参数,汽包水位的控制直接影响余热电站的安全运行。本文根据水泥回转窑余热发电的特点,阐述了余热锅炉汽包水位控制的任务及其重要性,分析了影响汽包水位的主要因素,介绍了余热锅炉汽包水位三冲量控制系统的结构、工作原理及其测量参数的校正方法。     

气化炉废锅液位的控制

1 总述锅炉水位调节常采用单冲量、双冲量及三重量三种调节方案。1．1 单冲量水位调系统这种类型的水位调节系统,被调参数是汽包水位,调节参数是锅炉的给水量,是一个典型的单回路调节系统。     

熔铸余热锅炉汽包水位的控制

针对熔铸余热锅炉汽包水位的特点,开发了基于汽包水位、蒸汽流量（微分）的双冲量控制方案。生产运行表明,该控制方案成功实现了使汽包水位平稳、波动小、给水稳定等目标。     

三冲量在石化行业的量化控制策略

介绍了汽包水位三冲量自动调节的量化控制策略,串级三冲量调节系统已经相当成熟,但在实际锅炉运行中各种原因导致水位自动调节系统投入困难,甚至自动不能投入。为此结合国内外石化项目,整理总结出三冲量的量化控制策略,通过实际运行,验证了其可行性和科学性。     

乙苯,苯乙烯的生产及合成乙苯,苯乙烯催化剂的研究进展

苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况，合成乙苯，苯乙烯所用的催化剂种类，并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。     

Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile

Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, ¹³C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc.     

生物质气化及生物质与煤共气化技术的研发与应用

总结了生物质原料的特点及生物质单独气化的缺点;介绍了国内外生物质气化技术及生物质与煤共气化技术的研发与应用现状;分析了在此领域国内外的发展趋势与前景;概括了开展生物质与煤共气化技术研发的意义。     

Electronic structures and reactivities of monometallic and bimetallic clusters of Au and Cu

The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu₃Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu₃Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters.     

钾盐资源及钾肥供需情况分析及预测

阐述了国内外钾盐资源及钾肥生产现状,对国内外钾盐的供需形势进行了分析及预测,从资源、原材料、国际市场三方面提出了解决我国钾盐短缺的措施。     

Kinetics and Mechanism of Oxidation of Mono- and Polyacetals

Abstract

Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed.     

Comparison of the Adhesion and Cohesion of Triblock and Random Copolymers of Styrene and Butadiene

A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength.     

Wetting properties of homopolymers and copolymers of pentafluorostyrene and methylacrylate and homopolymer blends

Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method¹ was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity.     

责任和责任心的涵义与结构

责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体.     

二甲基二烯丙基氯化铵和丙烯酰胺的合成及应用

用复合引发体系(过硫酸盐-偶氮类引发剂)和脂肪胺类氧化还原体系引发,在实验室获得了单体转化率≥98%,特性粘数高于13.6 dL/g的阳离子共聚物PDA,探讨了控制聚合物分子量的影响因素.