Pressure transmitters are one of the most used measuring devices in the petrochemical industry for automatic control. In large-scale chemical projects, almost all pressure transmitter applications are included: differential pressure, absolute pressure, gauge pressure, high pressure, differential pressure, high temperature, low temperature, and various materials and special processing of remote flange type Pressure Transmitters. For example, the Yangtze BASF styrene project uses nearly 480 various types of pressure transmitters. During the preparatory stage of the project, the experts and engineers of the project preparation department hope that all pressure transmitters can operate reliably for at least 2 years without failure.
At present, the pressure transmitters used in China's petrochemical industry mainly rely on imports, and domestic pressure transmitters have a certain gap with foreign countries in terms of product types and performance. Realizing the localization of pressure sensors is of great significance to the country's economic and national defense security and the revitalization of national industries. This paper analyzes the key points of localization of pressure sensors by comparing several typical pressure transmitters used in petrochemical industry at home and abroad. Through efforts, we can break the monopoly position of pressure transmitters based on MEMS sensors and realize the localization of pressure sensors in the petrochemical industry.
In the process of modern continuous production, stable and reliable pressure transmitter is a powerful guarantee for the production process. In the event of a metering error or even a downtime failure, the resulting economic loss will be uncountable. The stability and reliability of pressure transmitters have become the primary requirement for pressure transmitters in the petrochemical industry.
Typically, pressure transmitter measurements drift as the operating environment and static pressure change. In some small pressure or differential pressure measurements, this drift is likely to be more serious. Under different working conditions, the relatively correct measurement is obtained, thus maintaining the stability of production and ensuring the consistency of the process. It is the embodiment of the stability of the pressure transmitter and the stability requirement of the pressure transmitter in the petrochemical industry.
Based on stability and reliability, high precision is a higher demand for pressure sensors in the petrochemical industry. The accuracy of the control depends on the accuracy of the measurements during the control process. The higher the measurement accuracy, the higher the control accuracy. At present, the accuracy of most pressure transmitters reaches 0.075%, which can meet the measurement accuracy requirements of the petrochemical industry.
In addition, the petrochemical industry has many other needs for pressure transmitters. For example, increasing the turndown ratio increases the flexibility of the pressure transmitter for ease of design and application. When the design of some reaction conditions in the process changes, for example, the fruit transmitter has a large turndown ratio, which means that it has good versatility, and the change of process conditions does not affect the model of the transmitter. Reduced the amount of work required for design modifications. At the same time, the large-scale ratio can reduce the types of transmitters used in the project, reduce the inventory of spare parts, and reduce the backlog of funds.
The demand for pressure transmitters in the petrochemical industry is mainly concentrated on reliability, stability and high precision. Among them, reliability and many additional requirements, such as range ratio, bus type, etc., depend on the structural design of the transmitter, the level of machining technology and structural materials. The stability and high precision of the pressure transmitter are mainly guaranteed by the stability and measurement accuracy of the pressure sensor. Corresponding to the measurement accuracy of the pressure transmitter is the measurement accuracy and response speed of the pressure sensor. Corresponding to the stability of the pressure transmitter is the temperature characteristics and static pressure characteristics of the pressure sensor and long-term stability. The demand for pressure sensors in the petrochemical industry is reflected in measurement accuracy, rapid response, temperature characteristics, static pressure characteristics, and long-term stability.
The micro pressure sensor is a new type of pressure sensor made of semiconductor materials and MEMS technology. Compared with traditional pressure sensors, micro pressure sensors have the advantages of high precision, high sensitivity, good dynamic characteristics, small size, corrosion resistance and low cost. The material of pure single crystal silicon is fatigued, and the micro pressure sensor made of this material has good long-term stability. At the same time, the micro pressure sensor is easy to integrate with the micro temperature sensor, which increases the temperature compensation accuracy and greatly improves the temperature characteristics and measurement accuracy of the sensor. If two micro-pressure sensors are integrated, static pressure compensation can be implemented to improve the static pressure characteristics of the pressure sensor. It can be seen that the micro pressure sensor has many advantages that the conventional pressure sensor does not have, and can well meet the demand of the petrochemical industry for the pressure sensor.