Research And Optimization Of Ethylene Plant Separation System

Ethylene plant is the leading unit of the petrochemical industry,its production capacity marks the level of development of a national petrochemical industry.In recent years,the rapid development of domestic ethylene industry,becoming the world's second largest ethylene producer.However,ethylene plant production and operation is bound to bring some impact to the environment.With the constraints of energy and environmental resources,"energy conservation,emission reduction,cost reduction,efficiency" has become one of the industry's most important issues.Therefore,in-depth and detailed studying its process,optimizing the operation,saving the energy,have important significance for enterprises.This paper studies Daqing Petrochemical 600,000 t/y ethylene plant separation process,mainly for four aspects of in-depth research and optimization,as follows:Ethylene plant is a large energy consumption,material consumption process.The traditional sequence of start-up method will result in a large amount of the material to the torch.This paper mainly aims at the optimization of the start-up mode and the successful implementation of the undischarge start-up,through the application effect,compared to the traditional way of start-up,this start-up way reduces the materials discharge more than 80%in each time,reduces the cost and increases the efficiency.In order to improve the treatment capacity of CO₂,the traditional way to increase the alkaline concentration,increase the amount of alkaline circulation,etc,the above measures will affect the long-cycle operation of the alkaline washing system.Compared with the traditional method,this paper proposes a two-alkaline washing mode,a four-alkaline washing mode,which can effectively improve the CO₂ treatment capacity of the plant,and avoid the adverse effect of the increase of the amount of butter.At the same time,reduce alkaline consumption,increase device efficiency of plant.The difficulty of dryer switching/regeneration is the regeneration of air flow and temperature control during the progress of regeneration.Now,the plant mainly use the decoupling logic control.However,it demands a high level for field instruments,the instruments of many old plants are unable to meet that.This paper proposes the optimization scheme,which adopt to directly control the opening of valves in order to ensure the regeneration flow and temperature.After the implementation,the control logic is stable and reliable.Acetylene hydrogenation reactor is the key equipment of ethylene plant,which is related to whether the ethylene product is qualified.With the long-term operation of the device,the temperatures of each section of the reactor have a rising trend.By optimizing the influencing factors and the main parameters,the conversion and selectivity of the catalyst are improved to a certain extent,the operating period of catalyst is increased,the operation of the state are made better,to achieve the purpose of cost reduction.