先进控制技术在乙烯裂解炉上的应用

Application of APC on the furnaces of olefins plant

文章介绍了先进控制技术在乙烯裂解炉上的应用情况,先进控制方案及控制目标,展示了先进控制的实际效果。针对裂解炉运行特点,裂解炉先进控制方案采用霍尼韦尔的模型预测控制软件-Profit Controller和在裂解炉产率模拟软件-线SPYRO相结合的控制策略。在线SPYRO提供裂解炉的关键控制指标-裂解深度和最大管壁温度。Profit Controller应用鲁棒多变量模型预测控制技术实施对裂解炉的控制。裂解炉先进控制方案控制目标包括:1)稳定裂解炉操作;2)裂解深度控制;3)处理量最大化;4)节能。共18个先进控制器,每个控制器控制一个裂解炉。方案实施过程包括:功能设计、预测试、阶跃测试、模型辨识、离线仿真、在线仿真、现场投用等。在方案实施的同时对裂解炉出口温度和稀释比等控制回路进行了改进和整定取得显著效果。通过先进控制技术在乙烯裂解炉上的实施,装置运行更平稳,降低了操作人员劳动强度,提高了裂解炉控制水平,实现了裂解深度的在线控制,节能降耗。标定结果说明实施先进控制后双烯收率提高了0.27%,每年可节约原料费用4698.65万元,取得显著的直接经济效益和间接效益。

This is an introduction of the practical application of advanced process control system on Maoing＇s ethylene crackers, the control scheme of APC ,its control objectives and its effects. Based on the operation features of the furnaces, Maoming adopted Honeywell＇s APC soft-ware - Profit Controller and furnace yield simulation software - online SPYRO, which predicts critical furnace control parameters including cracking severity and maximum TMT. Profit Controller realizes the control of furnaces by applying the robust multivariable model predicative control technology. The control objectives of furnace APC solution include, 1） stable operation of furnaces, 2） severity control, 3） load maximization, 4） energy saving. There are 18 Profit controllers in the plant, one for each furnaces respectively. The APC control scheme implementation process includes function design, pre-test, step test, model identification, off-line simulation and commissioning. In the meantime, control loops, such as COT and dilution steam ratio, are optimized, and the results are obvious. With the implementation of APC, the control objectives are achieved, which lowered the labor stress of operators, improved the control of furnaces by online control of cracking severity and energy was saved. Performance test indicates that the yield of ethylene and propylene was improved by 0.27 % and the annual saving of raw materials totaled RMB 46.9865 million Yuan, which is significant in economic benefits both directly and indirectly.