Abstract:

This paper aims at the strategies to simulate the distillation process in a delayed coking unit(DCU)by using the simulation software of SimSci/PRO Ⅱ.Since the components of the reaction vapor in the DCU fractionation column are unknown and there are imbalanced trays at the bottom of the column,the compo sition of the high-temperature oil and gas feedstock in the fractionation column is inversely conjectured according to the composition of the products,an d the whole column is divided into two sections,namely the bottom heat-exchange section and the rectifying section.Then, the Grayson-Streed property choice method is adopted to simulate the fractionation process.Th e simulated results.which are consistent with the on-site ope rational data,indicate that there is an obvious fluctuant flowrate of the gas and the liquid along the trays.Moreover,a hydraulics calculation is carried out for.the main fractionation column,and a tray-load performan ce diagram is drawn .Th e results show that weeping ex-ists at most trays,which call be solved by plugging up some holes in the weeping trays.Finally,in accordance with the production requirements in the refinery,a simulation and a hydraulics calculation are perform ed for the fr~ tionation column whose processing capacity is increased by 22% .It is thus concluded that a partial revam ping of the fracfionation column can meet the requirements of production with enlarged capacity.

Key words: delayed coking unit, process simulation, SimSci/PRO Ⅱ, hydraulics analysis