Scaleup Strategies for Tubular Reactors

Sr or Sl can be chosen as the other. Tables 3.1-3.3 give both options. Choosing a specific valne for either of Sr or Sl is a matter of scaleup strategy. 

The reader is reminded of the usual caveat Detailed calculations are needed to confirm any design. The scaling exponents are approximate. They are used for conceptual studies and to focus attention on the most promising options for scaleup. Pick a promising strategy and then do accurate calculations to confirm the choice. 

There are several ways of increasing the capacity of a tubular reactor. 

Add identical reactors in parallel. This sets = S /, = 1 for each reactor. The number of reactors is A tube = -Sthroughput- The shell-and-tube design used for heat exchangers is a common and inexpensive way of increasing capacity by scaling in parallel. 

Make the tube longer. For a constant-density fluid, this strategy sets Sr = 1 and Sl = S. Adding tube length is not a common way to increase capacity, but it is done. Single-tube reactors exist that are several miles long. 

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We begin a discussion of scaleup relationships and strategies for tubular reactors. Results are restricted to tubes with a constant cross-sectional area. Chapter 3 discusses only isothermal or adiabatic reactors, but the relationships in Tables 3.1-3.3 include scaleup factors for the nonisothermal reactors that are discussed in Chapter 5. These results assume constant density, but Tables 3.4 and 3.5 give some specialized results for ideal gases when the pressure drop down the tube is significant. 

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