Abstract
The isomerization unit is a sub-device of the PX device. The device is mainly made up of xylene fractionation unit, adsorption separation unit, and xylene isomerization unit. The main purpose of the control system's design is to better control tower from heptane, improve the purity of the products and produce more products of better quality indicators. In the process of the design, as far as possible in the principle of optimal control production safety, improve production efficiency and increase the output of products, save money, protect the environment and reduce energy consumption , the system is designed.
In the design of automatic control system for isomerization unit from heptane tower of PX devices, single-loop control is used in the control programme. There is a total of 11 circuit , of which is 8 single-loop control system and 3 cascade control system. It has done the choice and relevant calculation on the controller, control valves and measurement devices used in the control system. There is a total of eight chapters in this design. The isomerization unit from heptane tower of PX devices is studied and researched, mainly on temperature, pressure, liquid level and flow.
The design adopts the CENTUM CS1000 Distributed Control System, which was produced by Michael Tien company in Japan Yokogawa. The Distributed Control System has reliable hardware, reliable operating, feature-rich software and good operating characteristics. In the process of energy conservation, control and optimize the consumption will play a positive role. For the future to further optimize the process control and advanced control, it has facilitated the application and laid the foundation for the realization of information for management and computer integrated control.
Key words: PX; Distributed Control System;CENTUM 1000; control system