减压深拔及结焦控制研究

Study on deep-cut vacuum distillation and coking control

结合减压深拔的技术特点,说明了影响减压深拔的相关条件,显而易见,提高减压炉的出口温度是实现减压深拔的必须途径,但温度的提高必然会增加油品结焦倾向;通过研究不同性质的油品在不同温度以及不同停留时间下对其结焦生成量(甲苯不溶物)的影响,得到不同性质油品的临界结焦曲线,分析了油品结焦原因和影响结焦的相关因素以及油品的深拔潜力;通过对加热炉管的结焦机理及其关系式的研究,结合油品的临界结焦曲线,指出不同性质的油品在减压炉加热过程中存在相对应的安全操作区域;分析讨论了减压塔内部构件结焦的预防和控制。阐述了油品深拔与结焦的内在联系,说明减压深度拔出的关键在于控制油品在减压炉管内及减压塔内部构件上不生成或少生成结焦,从而实现深拔条件下的长周期安全生产。

Based upon the characteristics of deepcut vacuum distillation, the major operating conditions that significantly influence the deepcut rate in vacuum distillation of crude oil haven been described. It is ob vious that elevating vacuum furnace outlet temperature is indispensable for increasing deepcut rate. Whereas, raising the temperature will increase the coking tendency of the oil products. By the study of impact of oil products of different properties on coke formation （ toluene insolubles） under different temperatures and differ ent residence time, the critical coking profiles of oils of different properties are developed, and coking of oils and factors affecting coking as well as vacuum deepcut potential are analyzed. The study of coking mecha nisms of furnace tubes, their correlation equations and critical coking profiles concludes that oils of different properties have their safe operating ranges in the heating process in vacuum furnace. The prevention and con trol of coking on vacuum tower internals are discussed. The internal relationship between deep cut and coking is described. The control or minimization of coking of oils on vacuum furnace tubes and vacuum tower internals are critical for the longterm operation under deepcut vacuum operating conditions.