浅析DCS和PLC控制系统供电安全

随着自动化控制技术的发展和进步,DCS和PLC控制系统在工厂中被广泛使用,生产过程控制高度依赖自动化技术,一旦DCS和PLC控制系统出现问题,将会给生产造成巨大影响,甚至会引发生产和设备事故。该文主要从DCS和PLC控制系统供电电源设计,UPS不间断电源选型维护和系统接地方面入手,并结合中铝东南铜业有限公司控制系统存在的问题,论述DCS和PLC控制系统供电安全。     

DCS控制系统在大型高炉上的应用

本文主要分析了DCS控制系统在某钢铁厂2000m2高炉控制系统中的应用，包括其工艺流程、控制系统结构、以及网络构成和实现控制功能等。并分析了DCS控制系统如何实现保障高炉顺利生产、维持高炉系统稳定以及对其进行严密监测。     

烧碱蒸发中的DCS控制

介绍了DCS控制系统在氯碱行业烧碱蒸发工艺中的应用,详细总结了烧碱蒸发过程控制、检测及部分数学模型.     

热电厂DCS控制系统与稳定性探讨

DCS控制系统是现代化热电厂重要的功能部分和组成部分,新时期的热电厂建设和改造过程中DCS控制系统是核心的部分,在发挥安全、稳定和经济效果的同时,使热电厂建设、发展、功能目标得以实现。本研究以热电厂DCS控制系统为研究中心,在分析热电厂DCS控制系统组成部分的基础上,研讨了热电厂DCS控制系统稳定性提高的措施,希望在维护热电厂DCS控制系统的同时,使热电厂DCS控制系统的价值得到进一步地体现。     

DCS控制系统在空分系统上的应用问题探讨

文章主要针对DCS控制系统在空分系统上的应用问题进行分析,在分析系统的工艺流程的基础上,论述了系统配置,最后重点就系统的热工检测和控制问题进行分析,希望对于今后的DCS控制系统在冶金行业中应用具有一定帮助。     

浅析某电厂四台机组脱硫保护优化

本文主要通过对某电厂脱硫DCS控制系统并入主控系统过程中潜在和面临的主要问题的分析,提出相关的DCS保护逻辑优化方案。进而通过一系列的实验、分析和实施,最终解决了这些影响机组安全稳定运行和主要设备异常状态下影响机组接带负荷能力的问题,保证了设备的安全可靠运行,使系统处于良好稳定的运行状态。     

600MW亚临界供热机组DCS升级改造消除隐患

随着电力体制改革的纵深发展,自动化水平的提高,发电企业现代单元机组热工控制系统主要由DCS控制系统实现,对于DCS系统网络的安全、稳定的要求至关重要。华电内蒙古能源有限公司包头发电分公司2＊600MW机组DCS控制系统为上海福克斯波罗公司的T／ASeries。目前通过升级改造消除了安全隐患。     

分散控制系统DCS在热电厂应用技术改进

目前,分散控制系统DCS已被广泛运用到各热电厂,在使用中实现了集危险分散、控制分散及管理集中的管理特点,为企业经济效益奠定了基础。本文在分析了分散控制系统DCS框架图的基础上,重点阐述了DCS控制系统在应用中锅炉汽包液位测量存在较大偏差及燃烧控制系统无法投自动的问题,进一步提出技术改造方案,得出结论。     

DCS在发电厂电气控制系统中的应用

在概述DCS控制系统及其特点的基础上,重点分析电厂电气控制进入DCS的目的,电厂电气系统纳入DCS监控的范围及发电厂DCS控制方式,为进一步研究发电厂DCS控制系统提供依据。     

国产ECS100控制系统在大型空分设备上的应用

以承德燕山气体40000m3/h空分设备的DCS控制系统为例,介绍国产ECS100控制系统的软、硬件构成及其特点,典型控制回路以及参数控制和过程调节控制功能;阐述大中型空分设备DCS控制系统实现国产化的意义。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.