化学化工专业英语翻译 reactor types.doc

Unit 4 Reaction Engineering Lesson 12 Reactor Types 1. Stirred tank reactor A batch stirred tank reactor is the simplest type of reactor.It is composed of a reactor and a mixer such as a stirrer, a turbine wing or a propeller. The batch stirred tank reactor is illustrated below: This reactor is useful for substrate solutions of high viscosity and for immobilized enzymes with relatively low activity. However, a problem that arises is that an immobilized enzyme tends to decompose upon physical stirring. The batch system is generally suitable for the production of rather small amounts of chemicals. A continuous stirred tank reactor is shown above: The continuous stirred tank reactor is more efficient than a batch stirred tank reactor but the?equipment is slightly more complicated. 2. Tubular Reactor Tubular reactors are generally used for gaseous reactions, but are also suitable for some liquid-phase reactions. If high heat-transfer rates are required, small-diameter tubes are used to increase the surface area to volume ratio. Several tubes may be arranged in parallel, connected to a manifold or fitted into a tube sheet in a similar arrangement to a shell and tube heat exchanger. For high-temperature reactions the tubes may be arranged in a furnace. 3. Fluidized bed Reactor A fluidized bed reactor (FBR) is a type of reactor device that can be used to carry out a variety of multiphase chemical reactions. In this type of reactor, a fluid (gas or liquid) is passed through a granular solid material (usually a catalyst possibly shaped as tiny spheres) at high enough velocities to suspend the solid and cause it to behave as though it were a fluid. This process, known as fluidization, imparts many important advantages to the FBR. As a result, the fluidized bed reactor is now used in many industrial applications. （1） Basic principles The solid substrate (the catalytic material upon which chemical species react) material in the fluidized bed reactor is typically sup