第39卷第7期2018年7月自 动 化 仪 表PROCESS AUTOMATION INSTRUMENTATION Vol．39No．7Jul.2018收稿日期:2017-12-14作者简介:王华强(1963 ),男,硕士,副教授,主要从事工业过程控制方向的研究,E-mail:wang hua qiang@https://www.doczj.com/doc/5e3607950.html, 基于科氏质量流量计的聚氨酯计量控制系统设计
王华强,陈 浩
(合肥工业大学电气与自动化工程学院,安徽合肥230009)
摘 要:作为一种重要的聚氨酯树脂合成原料,二苯基甲烷二异氰酸酯(MDI)价格昂贵且对产品性能影响显著,需要精确计量三在聚氨酯树脂规模化生产过程中,需要多次使用MDI三原计量系统采用一个科氏质量流量计(CMF),分别计量多个管道的MDI 质量三为避免管道中由于MDI 残留造成计量误差,在原计量系统的基础上,增加了多个CMF,并采用可编程逻辑控制器(PLC)控制三介绍了计量系统的结构和工作原理,给出了计量系统的控制流程三对比了改造前后的计量系统结构组成和特点,阐述了流量计的结构二原理和选型,比较了几种CMF 算法的优劣性三基于CMF 的聚氨酯计量控制系统在试生产中达到预期要求,提高了计量系统的测量精度三
关键词:聚氨酯;计量系统;科氏质量流量计;传感器;PLC
中图分类号:TH814;TP273 文献标志码:A DOI:10.16086/https://www.doczj.com/doc/5e3607950.html,ki.issn1000-0380.2017120017
Design of Polyurethane Metering Control System Based on Coriolis Mass Flowmeter
WANG Huaqiang,CHEN Hao
(School of Electric Engineering and Automation,Hefei University of Technology,Hefei 230009,China)Abstract :As an important raw material for synthesis of polyurethane resin,diphenyl-methane-diisocyanate (MDI)needs to be precisely weighed because it is expensive and has a significant impact on product performance.In the process of large scale production of the polyurethane,it is necessary to use MDI multiple times.In original metering system,Coriolis mass flowmeter (CMF)is used to respectively measure the mass of MDI in multiple pipelines.In order to avoid the measurement error caused by the residual MDI in the pipeline,a number of CMFs are added based on the original measurement system and PLC control is adopted.The structure and operation principle of the metering system are introduced,the control flowchart of the metering system is given.The composition and structural characteristics of the metering system before and after revision are compared,and the structure,principle and model selection of the flowmeters are described,the advantages and disadvantages of several algorithms of CMF are compared.The polyurethane metering control system based on CMF achieves expected results in trial production and
improves the measurement accuracy of the metering system.Keywords :Polyurethane;Metering system;Coriolis mass flowmeter;Sensor;PLC 0 引言
在聚氨酯树脂(polyurethane,PU)工业生产过程
中,不同的物料配比会导致产品具有不同的性能三企
业在生产不同用途的产品时,需要产品具有特定的性
能[1]三为了确定最佳的物料配比,企业在研发中需要试验不同的配方三作为一种重要的聚氨酯树脂合成原
料,二苯基甲烷二异氰酸酯(diphenyl-methane-
diisocyanate,MDI)因其价格昂贵且对产品性能影响显著,需要精确计量三在聚氨酯树脂规模化生产的过程
中要多次使用MDI,需由多个管道下料三原计量系统
中,企业采用一个科氏质量流量计(Coriolis mass flowmeter,CMF)分别计量多个管道的MDI 质量,而其他物料采用托利多秤称重计量三随着企业生产规模的扩大,由于管道中MDI 残留,采用单独CMF 计量的精度已不能满足要求三对于上述问题,本文在原计量系统的基础上,改进了计量仪表,比较了几种CMF 的算法,提高了物料的下料精度,减小了产品质量的波动三1 计量系统原理与结构某企业聚氨酯树脂生产采用高纯对苯二甲酸万方数据