基于PLC的导热油加热炉控制系统改造设计

发布时间：2019-05-07 11:22

【摘要】：本文以甘肃省张掖市某公路养护单位一台导热油加热炉控制系统改造为目的,设计使用可编程控制器自动控制加热炉,通过可编程控制器对加热炉几个部分的控制,使煤在最佳状态下燃烧,提高加热炉效率并降低成本、减少污染,提高生产过程的安全性;加热温度控制效果好,保持了沥青的原有质量,为铺筑高质量的公路提供了材料保证。设计完成导热油温度检测、炉膛内负压检测、给煤量控制、鼓风机控制、引风机控制、故障报警等各部分硬件设计和可编程控制器的软件设计,以负载需求热量的多少(以加热炉出口油温为衡量标准)来控制加热炉内煤的燃烧情况,最终实现加热炉的自动运行。本设计主要思想是把加热炉出口油温、炉排电机转速和鼓风电机转速信号通过模数转换送入可编程控制器中,可编程控制器将传入温度信号与预设值进行比较,从而发出相应指令,以调节炉排电机转速(调整给煤量),并改变鼓风机转速(调整空燃比);把炉膛内负压值信号送引风机变频器,经处理后调节引风机转速(调整加热炉内负压),从而使燃煤燃烧在最佳状态,加热炉实现自动控制。选用西门子S7-200型可编程控制器的CPU224XP为控制模块,采用PT100热电阻来检测导热油温,用EM231热电阻模块变送信号并输入控制模块;采用PTP708F压力传感器检测加热炉膛内负压并将电流信号输入引风变频器;采用变频器来控制炉排电机、鼓风机、引风机的转速。利用西门子STEP7编程软件进行软件开发。
[Abstract]:For the purpose of transforming the control system of a heat conduction oil heating furnace in a highway maintenance unit in Zhangye City, Gansu Province, this paper designs and uses a programmable controller to automatically control the heating furnace, through which several parts of the furnace are controlled by a programmable controller. The coal combustion in the optimum condition can improve the heating furnace efficiency and reduce the cost, reduce the pollution, and improve the safety of the production process. The heating temperature control effect is good, the original quality of asphalt is maintained, and the material guarantee is provided for paving high-quality highway. The hardware design and software design of such parts as temperature detection of heat conduction oil, negative pressure detection in furnace, control of coal supply, control of blower, control of draft fan, alarm of fault, and software design of programmable controller are completed. The coal combustion in the reheating furnace is controlled by the amount of heat required by the load (measured by the oil temperature at the outlet of the furnace), and the automatic operation of the furnace is finally realized. The main idea of this design is to send the signals of oil temperature at the outlet of the furnace, the speed of the grate motor and the speed of the blast motor into the programmable controller through analog-digital conversion. The programmable controller compares the incoming temperature signal with the preset value. Thus the corresponding instructions are issued to adjust the speed of the grate motor (adjust the coal feed) and to change the speed of the blower (adjust the air-fuel ratio); The negative pressure signal in the furnace is sent to the frequency converter of the draft fan. After treatment, the speed of the draft fan is adjusted (the negative pressure in the furnace is adjusted), so that the combustion of coal is in the optimum state and the furnace is automatically controlled. The CPU224XP of Siemens S7-200 PLC is selected as the control module, the thermal resistance of PT100 is used to detect the heat conduction oil temperature, and the signal is transmitted by the EM231 thermistor module and input into the control module. The PTP708F pressure sensor is used to detect the negative pressure in the heating furnace and input the current signal into the frequency converter, and the frequency converter is used to control the rotating speed of the grate motor, the blower and the induced draft fan. Using Siemens STEP7 programming software to carry on the software development.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U418.3

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