Study On Low-emission Startup And Shutdown Of Ethylene Plant

The process of start-up and shutdown for ethylene plant involves a long process and complicated operations.When the entire plant is operating in an unsteady state,it is prone to operational failures and accidents.In order to ensure the safe and smooth operation of the start-up and shutdown,it is difficult to avoid the emission of the flare system due to the operation of the process and equipment.During the combustion of the discharged material,a large amount of carbon monoxide,carbon dioxide,nitrogen oxides,incompletely burned organic compounds and etc.will be generated,which have a certain impact on air quality.Therefore,it is of great significance for the ethylene plant to optimize the start-up and shutdown operation,and reduce material emissions,the cost and the adverse impact on the environment.By analyzing the typical problems and the difficult points in the low emission process of start-up and shutdown for ethylene plant,this paper optimizes the start-up and shutdown scheme,formulates and implements the preventive measures,connects the start-up and shutdown steps,minimize the driving time and maximize the recycle of parking materials,and achieves low emission,high efficiency and economical start-up and shutdown.The optimization of the starting scheme of the ethylene refrigeration compressor eliminate the surge phenomenon in the starting process.The modification of the control system of cracking gas compressor improve the operation safety of the unit under the condition of non-steady state,make the parking process more economical and environmental friendly.This paper describes the general principles,methods,important control points,and especially the preventive measures that easily occurred in the low emission process of start-up and shutdown for ethylene plant to ensure the security,environmental protection and economy.