In reactor design we want to know what size and type of reactor and method of operation are best for a given job. Because this may required that the conditions in the reactor vary with position as well as time . this question can only be answered by a proper integration of the rate equation for the operation . This may pose difficulties because the temperature and composition of the reacting fluid may vary from point within the reactor ,depending on the endothermic or exothermic of the reaction, the rate of heat addition or removal from the system ,and the flow pattern of fluid through the vessel. In effect ,then many factors must be accounted for in predicting the performance of a reactor .How best to treat these factors is the main propelm of reactor design.
Equipment in which homogeneous reactions are effected can be one of three general types ;the batch ,the steady state flow and the unsteady state flow or semi batch reactor. The first two categories.
Lest us briefly indicate the particular features and the main areas of application of these reactor types. Naturally these remarks will be amplified further along in the text. The batch reactor is simple, needs little supporting equipments, and is therefore ideal for small scale experimental studies on reaction kinetics. Industrially it is used when relatively small amounts of material are to be treated .The steady state flow reactor is ideal for industrial purposes when large quantities of material are to be processed and when the rate of reaction is fairly high to extremely high. Supporting equipment needs are great; However ,extremely good product quality control can be obtained . As may be expected ,this is the reactor that is widely used in the oil industry. The semi batch reactor is a flexible system but is more difficult to analyze than the other reactor types. It offers good control of reaction speed because the reaction proceeds as reactant are added. Such reactors are used in a variety of applications from the calorimetric titration in the laboratory to the large open hearth furnces for steel production.
The starting point for all design is the material balance expressed for any reactant .Thus ,as illustrated in below:
(rate of reactant flow in) =(rate of reactant flow out)+(rate of reactant loss)+(rate of accumulation of reactant)
Where the composition within the reactor is uniform (independent of position) , the accounting may be made over the whole reactor. Where the compositions is not uniform, it must be made over a differential element of volume and then integrated across the whole reactor for the appropriate flow and concentration conditions. For the various reactor types this equation simplifies one way or another ,and the resultant expression when integrated gives the basic performance equation for that type of unit. Thus, in the batch reactor the first two terms are zero; in the steady state flow reactor the fourth term disappears; for the semi batch reactor all four terms may have to be considered.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .