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Space time (or space-time) is the time necessary to process one reactor volume of fluid, given a particular set of entrance conditions. Commonly represented by the Greek letter τ, it is obtained by dividing the reactor volume by the volumetric flow rate entering the reactor. It is the equivalent to the hydraulic retention time (HRT=V/Q).〔Elements of Chemical Reaction Engineering (4th Edition) by H. Scott Fogler, Prentice Hall PTR, 2005. ISBN 0-13-047394-4〕 The space time is frequently used in calculation involving chemical reactors and is often a more useful quantity to work with than the average residence time. The average residence time and the space are equal if all of the following conditions are met:〔Chemical Engineering Kinetics and Reactor Design by Charles G. Hill, Jr. John Wiley & Sons Inc, 1977. ISBN 978-0471396093〕 # Temperature and pressure are constant # The reaction proceeds with constant density # The volumetric flow rate is evaluated at reactor inlet conditions ==Design Equations== Design Equations are equations relating the space time to the fractional conversion and other properties of the reactor. Different design equations have been derived for different types of the reactor and depending on the reactor the equation more or less resemble that describing the average residence time. Often design equations are used to minimize the reactor volume or volumetric flow rate required to operate a reactor.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Space time (chemical engineering)」の詳細全文を読む スポンサード リンク
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