| The heavy oils deep processing and comprehensive utilization projects adopt the method of heating and distillation to split the crude oil into oil and semi-finished products with different boiling point degrees through condensation and vaporization repeatedly.The crude oil is separated into naphtha,aviation kerosene,diesel oil,gas oil and so on.Afterwards,the output would be transported to downstream units.The products of the heavy oil deep processing and comprehensive utilization project constitute the basic raw materials of the downstream chemical refining and fine chemical industries in large scale.Thus,it is considered that the performance of product determines the superiority and profit of the whole refining system.There are many refining chemical bases in China at present.However,what extends the industrial chain is the chemical bases distribute dispersedly with low production capacity.Since most automation systems of units are old and many control loops haven’t been put into automation,the failure rate is high.Therefore,study on automation scheme for deep processing and comprehensive utilization project of heavy oil 1 million tons per year,is meaningful to guarantee that the plant’s automation could achieve international advanced level.Thus,the unit could maintain efficient production too.This paper firstly studies the process flow of heavy oil deep processing and comprehensive utilization project,meanwhile,determine the control variables and project’s control indicators.Then,it develops and realizes the automation scheme design in several aspects including engineering document,software & hardware,network architecture,control solutions,and system configuration.Focusing on the fluid characteristics and process data of crude oil as well as vacuum distillation unit products,the paper conducts site intelligent instrument & control valve selection.Considering the requirement of control quality and economic impact,Honeywell’s PKS system is selected as the automatic control system.To improve the control quality,the paper conducts detailed comparison analyze on each main production object and control plan with emphasis.Control plans of single loop,cascade,cascade averaging/uniformity,forward-feedback are adopt to ensure the stability of vacuum system for comprehensive utilization unit.The control plans also guarantee products’ quality is up to standard.Afterwards,the configuration realization of server,controller,operation station,simple loop,complex loop and process flow diagram,which all contained in control system,is completed and then the historical data and report are generated.Finally the unit startup successfully and run smoothly at the primary trial run.Besides,the application rate of control loops reach 100%.The gratify fact certifies that the automatic control plan of this project meets the expectations. |
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