Views: 1 Author: Site Editor Publish Time: 2022-05-30 Origin: Site
Driven by the rapid development of science and technology, major breakthroughs have been made in automation technology, and various automation equipment has emerged, which has greatly promoted the automation and modernization of petrochemical production. In the petrochemical automation control system, the automatic instrument plays an irreplaceable and important role, and the fault diagnosis and analysis of the instrument has also become an important task in the petrochemical industry.
In order to realize the automation of petrochemical production, it is necessary to comprehensively monitor the temperature, pressure, flow and other data in the production process. These functions are realized by corresponding detection instruments. Once the instrument fails, it will have a serious impact on the normal operation of chemical production. Therefore, the staff must be proficient in the physical structure of the instrument, the measurement principle and the performance index, etc., and can accurately diagnose and deal with the instrument failure, so as to ensure the normal progress of chemical production.
The chemical reactions and changes in petrochemical production need to be carried out smoothly under a specific temperature and pressure environment. In order to monitor temperature changes in real time and precisely control the temperature range, a certain number of temperature instruments must be installed in production. At present, the production temperature is mainly measured by contact, and the temperature data is measured by temperature measuring elements such as thermocouples and thermal resistances, and the automatic temperature control effect is achieved with the help of field bus technology.
There are various types of pressure instruments, such as pressure sensors, pressure transmitters, and special pressure gauges. Under normal circumstances, the pressure regulation system will transmit the collected signals to the distributed control system with the help of pressure transmitters to achieve automatic pressure measurement and control effects.
According to the different measurement methods, level instruments can be divided into buoyancy type, direct reading type, differential pressure type, radiation type, radar type, etc. In petrochemical production, radar type level instruments have high measurement accuracy, and at the same time Petrochemical materials have strong applicability and are gradually being favored by the industry.
Flow meters are basically based on two measurement principles, one is volume flow measurement, and the other is mass flow measurement. Specifically, there are throttling type, differential pressure type and velocity type.
Cause Analysis of Instrument Failure
Usually, the automatic control instrument consists of three parts: sensor, transmitter and display. The sensor is responsible for the detection of the analog signal of the measured object; the transmitter is responsible for converting the signal output by the sensor into a standard current signal (4~20 mA), and at the same time transmits the signal to the PLC controller; the display is responsible for the intuitive display of the measurement data.