The Design And Application Of Air Separation Unit Control System Based On PKS

Air separation unit plays an important role in the economic development process,oxygen, nitrogen, argon and other gases are widely applied in all aspects of productionand life. As in recent years, the rapid development of China’s chemical industryincrease the demand for industrial gases, it brings new vitality to the development andresearch of air separation units.QinghaiYanhu Chemical II20000air separation unit, use the process of fulldistillation, internal compression and argon producing without hydrogen. Oxygen andnitrogen are important raw material of subsequent production. They are one of the mostcrucial part of the whole production chain. This requires of safe and efficient operationfor air separation control unit.The main work of this article include:First, briefly describes the process of air separation unit, this proposed controlrequirements of five systems in air separation unit.Second, analysis the scale of control systems, design the control system hardwarefrom hardware design and selection, redundant control requirements, and ITCCcommunications and interlock.Third, Detailed molecular sieve configuration process such as sequence control,control loop design, and the use of VB script. Through the tests and actual running,pre-cooling systems, molecular sieve achieved good control effect, expander anti-surgecontrol can protect the unit effectively.Forth, analyzes the distributed control requirements of air separation unit, andPKS system advanced algorithm library has its limitations, so the distributed predictive control algorithm is introduced, the form of the algorithm is described. Taking anexample as air fractionator, describes a distributed prediction the control configurationin PKS. Build a mathematical model of fractionator and complete system simulation,simulation results show the effectiveness that output variable can be a good tracksettings.In the process of control system design, implementation is mainly focused on theVB script in molecular sieve pausing program and the application of anti-surge controlpoint. The application of script supplement function block, greatly enriched thefunctionality of the system, provides a new train of thought to solve the problem. Innarrative process, this article also summarizes the design and configuration process insome of the problems, provide reference for configuration.