《基于PLC的锅炉测控系统设计》-毕业论文（设计）.doc

PAGE 基于PLC的锅炉测控系统设计 摘 要 本文以实际的工业锅炉为对象，详细介绍一种工业锅炉自动控制系统的设计过程。该系统采用西门子PLC S7-300系列做控制层，工业组态软件WinCC制作工业监控层。 锅炉的控制系统主要有汽包水位控制系统、燃烧控制系统、炉膛负压控制系统、蒸汽温度控制系统等四大控制系统。汽包水位控制采用三冲量控制：以汽包水位作为主控制信号构成主调节回路，以蒸汽流量作为前馈信号构成前馈调节回路，以给水流量作为串级信号构成副调节回路。燃烧控制主要分为燃料控制和送风量控制。燃料控制以蒸汽压力作为主调节信号，以蒸汽流量作为副调节信号；送风量控制主要控制含氧量，因为燃料是否完全燃烧取决于炉膛中空气的多少，在此控制系统中，汽包压力调节器的输出信号作为前馈信号引致送风副调节器。炉膛负压控制系统只需将送风调节器的输出信号引入调节器作为前馈信号，保证炉膛压力为-20Pa的微负压。 关键词：锅炉；汽包水位控制；燃烧控制；汽温控制；PLC The boiler control system based on PLC Abstract Based on the actual industrial boiler, introduced a kind of industrial boiler design process of automatic control system. This system USES Siemens S7-300 series PLC control layer, do WinCC configuration software industry production industrial control layer. The boiler control system are mainly drum water level control system, the combustion control system, hearth negative pressure control system, the steam temperature control system, control system, etc. Drum water level control using three impulse control: to drum water level control signal constitute the main steam flow adjusting loop to constitute a feed-forward signal feed-forward loop to adjust water flow as a cascade signal regulating circuit constitute vice. Burning control mainly divided into fuel control and airflow control. Fuel control with steam pressure as the main control signal to steam flow as deputy regulates signal, Send airflow control mainly because the fuel, oxygen control whether complete combustion chamber depends on how much, the air in the control system of steam pressure regulator, the dwellings signal as deputy regulator caused by air feed-forward signal. Hearth negative pressure control system of air conditioner will only output signal into a feed-forward signal, ensure the regulator for -20Pa chamber pressure of the pressure. Key words: Boiler；Drum water level control；Burning control；The steam temperature control；PLC 目 录 TOC \o 1-3 \h \z \u HYPERLINK \l _Toc265346636 摘 要 PAGEREF _Toc265346636 \h I HYPERLINK \l