先进控制技术(APC)在大型延迟焦化装置的应用

Application of Advanced Process Control Technology in Large-scale Delayed Coking Unit

先进控制技术（APC）目前正在复杂化程度高的流程工业中普及应用。Aspen公司的DMCplus技术采用动态矩阵控制算法（DMC）作为核心算法,其基本特征包括预测模型、滚动优化、反馈校正,为典型的多变量模型预测控制算法。某炼化公司延迟焦化装置设计加工规模为420×104t/a,采用两炉四塔工艺路线,采用Aspen公司DMCplus先进控制技术设计了4个先进控制器：加热炉支路平衡控制器、加热炉炉效率控制器、主分馏塔控制器、吸收稳定控制器。先进控制器投运后,能自动过渡焦炭塔预热、切换等过程,并抵御这些过程中带来的干扰,保证24h不摘除,减轻劳动强度;平稳装置操作,大部分工艺参数点标准偏差降低20%以上,关键被控变量的标准偏差降低30%以上;提高加热炉炉效率,优化分馏塔温度分布,并提高高价值产品产率,优化了吸收稳定装置的流量和温度分布,节能降耗;提供相应软测量预测,软仪表计算值与化验值之间的偏差满足工艺要求。每年创造经济效益2600多万元。

Advanced process control（APC） technology is now being popularized in the highly complex pro-cess industry.Aspen′s DMCplus technology uses dynamic matrix control（DMC） algorithm as the core algorithm.With the basic features of predictive model,rolling optimization and feedback correction,it is a typical multivariable model predictive control algorithm.The 4.20 Mt/a delayed coking unit in a refinery adopted a two-fur-nace and four-column process route.Aspen ′ s DMCplus technology was used to design four advanced controllers,i.e.fired heater branch balance controller,fired heater efficiency controller,main fractionator controller and absorption stabilization controller.After these advanced controllers were put into use,the automatic transition of preheating,switching and other processes in coke drum were achieved,the interferences in these processes were resisted,and the labor intensity was reduced.The unit operation was stabilized,the standard deviation of most process parameters was reduced by more than 20%,and the standard deviation of key controlled variables was reduced by more than 30%.The efficiency of fired heater was improved,the temperature distribution in fractionator was optimized,the yield of high-value products was improved,the flow and temperature distribution in absorption stabilization unit was optimized,the energy was saved and the consumption was reduced.Corresponding soft sensor prediction was provided,and the deviation between the calculated value of soft sensor and the test value meets the process requirements.An annual economic benefit of more than 26 million yuan was achieved.