科技文献的阅读及翻译方法.ppt

Heat transfer and its applications Mass transfer and its applications Principles of diffusion and mass transfer between phases Theory of diffusion Gas absorption Equilibrium-stage operations Distillation and multi-component distillation Leaching and extraction Drying of solid Fixed-bed separation Crystallization Special topics – Separation Engineering (some typical unit processes…Distillation / Crystallization) Distillation: a process in which a liquid or vapour mixture of two or more substances is separated into its component fractions of desired purity, by the application and removal of heat; Distillation columns are designed to achieve this separation efficiently. It has long held pride of place as the major processing operation in the petroleum industry. Distillation Types of columns Batch Columns: In batch operation, the feed to the column is introduced batch-wise. That is, the column is charged with a batch and then the distillation process is carried out. When the desired task is achieved, a next batch of feed is introduced. Continuous Columns: In contrast, continuous columns process a continuous feed stream. No interruptions occur unless there is a problem with the column or surrounding process units. They are capable of handling high throughputs and are the most common of the two types (In terms of the type of column internals, it includes tray column and packed column). Distillation Basic distillation equipment and operation Main Components of Distillation Columns Distillation Column internals Trays and Plates: Bubble cap trays Valve trays Sieve trays Packings Packings are passive devices that are designed to increase the interfacial area for vapor-liquid contact. The following pictures show 3 different types of packings. Packings versus Trays A tray column that is facing throughput problems may be de-bottlenecked by replacing a section of trays with packings. This is bec