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高温粉尘工况下雷达料位测控系统的研究
于海洋
Subtype硕士
Thesis Advisor宋文立 ; 都林
2016-07
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Discipline化学工程
KeywordDcs 雷达 料位 信号处理
Abstract

在工业自动化领域,基于DCS建立远程过程控制的自动化技术已经很成熟。然而,利用雷达测量料位作为反馈信号参与自动化控制还仅限于检测液态、静态介质等干扰较小的工况,这类工况下雷达信号稳定、精度高,足够满足过程控制的实时性要求。在复杂工况下,雷达料位计当前主要应用于冶金、焦化、水泥等行业,例如高炉、焦炉和水泥窑的料位测量,在这类高温粉尘工况下,雷达料位计测量的料位的距离高达几米甚至几十米,对精度和实时性要求也不高,且测量结果不参与实时控制。本研究的目的就是尝试在600℃左右的煤热解生产过程中利用雷达料位计测量反应器内垂直距离2米范围内的高温混合物料的料位H,并建立一个基于DCS的以此测量结果做为反馈信号的过程料位自动控制系统。研究发现影响雷达料位测量可靠性的因素有两个:一是雷达料位计本身的制造工艺包括设备结构、尺寸及测量环境的影响因素,该类影响可以在搭建或设计该测量系统时人为的消除或避免;二是雷达料位计的信号处理系统不能准确和实时的处理当前复杂工况下的回波信号,该类影响必须通过改变信号处理的算法,即从软件改进的角度来消除。经过加装水冷、弯曲并加长导波管的措施使雷达料位计有效的避开高温辐射的影响,设备能够在500-800℃高温工况下正常连续工作;加装氮气吹扫不但有效的防止了焦油结块的影响,而且气流柱有效的减少了雷达照射路径上的粉尘影响;在信号进行FFT变换后对信号进行频谱分析时,加入动态限幅和偏差阈值的算法,可以有效消除空间运动颗粒引起的干扰信号,使雷达料位计测量的可靠性大幅提高。

Other Abstract

Abstract The technique of DCS has been broadly used for industrial automatic control. However, the application of radar for real-time distance measurement with high precision and high steadiness, is still restricted to those simple systems like liquids or static medias with little disturbance. For complicated processes in metallurgy, coal coking, and cement industries, the bulk material level mater was merely used for long distance measurement (commonly from several meters to tens of meters) with no requirement of real-time, and can just give an approximate result. Herein, the work is to establish a method for level measurement in the process of coal pyrolysis at 600?C within a short distance of 2 meters through a radar, and establish a system for level control based on the feedback of the measuring signal via a DCS platform.It was found that there were two major factors affecting the radar measuring reliability. The first one relates to the design and application environment of the radar including the structure and the size of the equipment. It could be improved by design . The second one relates to a signal processing of the instrument, since the echo signal obtained in complicated conditions cannot be directly used for an accurate calculation. It could be solved by improved algorithm for signal processing using the software.In this work, a water-cooling system, a bending tube, and a prolonged wave guide section were applied to avoid a high temperature radiation, by which the instrument can be used in 500-800oC conditions. The installation of purging nitrogen can effectively inhibit the tar induced agglomeration and eliminate the influence of dust. The signal interference caused by the movement of particles could be avoided by adding dynamic limiter and deviation threshold to the algorithm for signal spectrum analysis, after the transformation of FFT, through which, the instrument measuring reliability was improved. 

Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/22942
Collection研究所(批量导入)
Recommended Citation
GB/T 7714
于海洋. 高温粉尘工况下雷达料位测控系统的研究[D]. 北京. 中国科学院研究生院,2016.
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