REACTORS: IDEALIZED CHEMICAL REACTORS - Biomass as a Sustainable Energy Source for the Future - page 163

where ν i is the stoichiometric coefficient of species i and n i is the number of moles of i .

Note that ν i is negative for reactants and positive for products. For open (or continuous

flow) systems, the extent of reaction is defined as

= φ n , i − φ n , i 0
ν i

ξ ð Eq : 6 : 6 Þ

where φ n , i is the mole flow rate of i . Note that this means that the unit of ξ is different

for closed and for open systems! The main difference between and X i is that

conversion is dimensionless and describes how much of a certain reactant has reacted.
It is therefore dependent on the reactant considered. In contrast,

ξ

describes howmuch
the reaction has evolved and is independent of the reactant chosen for its assessment.

ξ

6.2 BATCH REACTORS (BRs)

6.2.1 Isothermal Batch Reactors

Isothermal means constant temperature . It is therefore a term describing those systems
in which the temperature does not change. In a batch reactor (BR), during reaction, no
reactants are supplied to the reactor and no products are released (Figure 6.1). The BR

V, c A
X A , (- R A )

FIGURE 6.1 Schematic of a batch reactor.