Application of paperless recorder in rotary kilns of cement enterprises
Gongyuan cement plant is one of the large backbone enterprises in the building materials industry. There are four dry process hollow cement rotary kilns with waste heat boilers. The specifications of #1 and #2 kilns are Φ 3.73.3 m × 70m, #3 kiln specification is Φ 3.3 m × 58m, #4 kiln specification is Φ 4.0 m × 70m; The annual output of cement is more than 1million tons. Clinker calcination is the central link in the cement production process. Accurate detection and reasonable control of the main thermal parameters in the clinker calcination system: kiln tail temperature, kiln speed, negative pressure, etc. will help to ensure the full performance of cement production process equipment and long-term safe operation, so as to achieve high-yield, high-quality and low consumption production. Since August, 2001, our factory has adopted DR18C paperless recorder integrating measurement and management to detect seven parameters such as tail temperature, negative pressure, rotating speed on #1 and #2 kilns and the weight of #4 kilns, and the effect is good
1dr18c paperless recorder introduction
dr18c paperless recorder (hereinafter referred to as Dr recorder) is the third generation of paperless recorder, which adopts a wide viewing angle, wide temperature, 640 × 480 dot matrix liquid crystal display recording curve; Flashram quickly stores recorded data; Three new technologies for highly reliable disk data backup. In addition, the display also has two output interfaces: field operation display and management operation display, which can meet different needs respectively. Dr recorder has 16 full intelligent analog input channels, which is small in size and low in power consumption, and can directly receive the input of thermal resistance, thermocouple and standard signal. Therefore, the voltage signal (MV) generated after the kiln tail temperature is detected by thermocouple can be directly input into the channel of Dr recorder; The rotary speed, negative pressure of the kiln and the bin weight signal of the silo only need to be converted into a 4 ~ 20mA standard signal and then sent to the channel of the Dr recorder
2dr recorder's field operation and display
the Dr recorder installed on the #1 and #2 kiln head operation console can display the results in real time on its LCD screen in the form of numerical value or curve through the detection of kiln tail temperature, kiln speed, negative pressure and bin weight. There are eight kinds of display screens on site, of which the main screen can display the seven parameters detected at the same time# 1. #2 the fire watcher at the kiln head can adjust the operation state of the kiln in time according to the display results of the main screen and his years of fire watching experience. For example, when the detected tail temperature is too high or too low on the main screen, it is necessary to adjust the amount of coal injection in time, so as to ensure the production of clinker with good quality, high output and low consumption. In addition, various function buttons are set on the main screen to facilitate operations such as screen selection, channel selection, recall of historical records and data storage
3dr recorder operation display on the management computer
dr recorder is equipped with data analysis software for management operation. The software is developed with VB and can be installed on the office management computer. Its functions are set to read data floppy disk, display selection (digital display and flow cumulative display), printing, zoom and range. After entering the software, you can call up the data in the field copy data disk, and display it in the form of numbers or curves on the screen, or print it out from the printer for long-term storage or management production
4 use effect
although the Dr recorder only detects the field data and does not directly control the production, its detection results are true and reliable, which provides timely and reliable information and basis for the kiln head to see the pyrotechnics and ensure that the kiln is always in good operation, and achieves the effect that the closed-loop control system can bring. After nearly two years of use, its advantages and effects are as follows:
(1) the tail temperature control is stable and well documented, basically eliminating the phenomenon of high tail temperature operation. Before installing the Dr recorder, the tail temperature during shift handover is too high and unclear. After installing the Dr recorder, it can not only accurately determine the tail temperature during shift handover, but also provide a basis for assessment; Moreover, it provides accurate data for the tail temperature control, ensures the effective implementation of the process system, and greatly reduces the phenomenon of coil formation
(2) played an effective supervisory role in the control of negative pressure. The number of revolutions of the exhaust fan directly controls the ventilation volume in the kiln. Before installing the Dr recorder, there is no effective monitoring means for negative pressure control. For example, some people see that the pyrotechnics increase the exhaust without permission in order to improve the output in their own shift, but it has a considerable negative impact on the stability of the whole kiln by clamping the standard tensile sample of the corresponding force value on the experimental machine, which is easy to cause the phenomenon of ring formation. After installing the circular film recorder with the thickness of 6mm, the negative pressure can be effectively monitored, which plays a positive role in the stable operation of the rotary kiln
(3) monitoring of kiln speed the digital calibration technology of electronic tensile testing machine is also ahead of its domestic counterparts at the beginning of this century. The #1 and #2 kilns in our factory require that the kiln drive should not exceed 1r/min. Beyond this revolution, the rotary kiln will run unevenly, which will affect the kiln lining. Since the Dr recorder is adopted, the kiln speed can be monitored at any time, and the phenomenon of excessive kiln speed is eliminated
(4) effective monitoring of raw material bin weight of rotary kiln. Since the use of Dr recorder to monitor the weight of raw material bin, the weight of raw material bin has been controlled above 12t, eliminating the phenomenon of low storage level and playing a decisive role in the stability of materials in the kiln
after nearly two years of use, we believe that the measurement accuracy, display reading and data recording of Dr recorder are relatively satisfactory, and basically reach the maintenance free state. In addition, because the paperless recorder adopts advanced microcomputer technology, it has all-round analog input, small volume, low power consumption, wide versatility, strong independence, bright picture color, intuitive reading, sensitive and reliable reflection, convenient data storage and recall. It is a good equipment integrating measurement and management. Therefore, we believe that the recorder can not only be used in rotary kilns, It can also be used for the detection of other equipment parameters in cement enterprises and other industries
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