FCS在制氧工艺中的应用

针对制氧工艺监控点较分散、控制回路较多的特点,采用SIEMENS PCS7控制系统,实现了生产过程的集中控制.对于压缩机存在的喘振现象,分析了喘振产生的原因和喘振的机理,提出了一种基于规则的工作点跟踪防喘振控制算法,有效地防止了喘振的发生,减少了因放空阀提前打开而造成的能量损失.在制氧过程中,分子筛吸附、再生的切换是空气纯化的核心流程,切换既要严格按照工艺要求进行,又要能够在特殊的情况下灵活地进行更改,采用PCS7中的SFC编程语言实现切换的顺控,完全满足了生产要求.

Application of FCS to Oxygen-making Process

To the problem that there are many distributed multi-control loops in oxygen-making process,a process control system with SIEMENS PCS7 is introduced.Surge is the main problem of compressor.The inducement and principle of surge are analyzed.The rule based on work-point following anti-surge algorithm is presented.The occur of surge is prevented efficaciously,and the loss of energy due to the exhausting valve's early opening is reduced.In the process of air purifying,the switching of molecular sieve adsorption and recondition not only fulfills the requirements of the production,but also can be manually changed in special condition.The sequence control of switching is implemented by the SFC of PCS7.