Page 299 - Introduction to chemical reaction engineering and kinetics

280 Chapter 11: Preliminary Considerations in Chemical Reaction Engineering

relate to technical feasibility (e.g., can the required fractional conversion be achieved in
the size specified?), and to socio-economic feasibility (cost, safety, and environmental
considerations). The factors to be taken into account are listed in more detail in the
next section.
The design problem usually fits into the spectrum ranging from (1) the rational design
of a completely new reactor for a new process, to (2) the analysis of performance of an
existing reactor for an existing process. A common situation, between these extremes,
even for a new plant, is the modification of an existing type of reactor, the design of
which has evolved over time.

11.1.1.2 Matters for Consideration
Process design involves making decisions about a series of matters, on as rational and
quantitative a basis as possible, given the information available. The following is an
illustrative list of such matters but not an exhaustive one; the items are not all mutually
exclusive.
(1) type of processing
batch
continuous
semibatch or semicontinuous
batch with respect to (specified phase or phases)
continuous with respect to (specified phase or phases)
(2) type and nature of reacting system
reactant(s) and product(s)
simple
complex (desirable, undesirable products)
stoichiometry
phases, number of phases
catalytic (choice of catalyst) or noncatalytic
endothermic or exothermic
possibility of equilibrium limitation
(3) type and size of reactor
batch
continuous
stirred tank
tubular, multitubular
tower/column
spray
packed, plate
bubble
bed
fixed
fluidized
spouted
trickle
furnace
(4) mode of operation
configurational
single-stage or multistage (number of)
parallel (e.g., multitubular)
axial or radial flow (through fixed bed)
arrangement of heat transfer surface (if any)