F. Nomenclature

A

Chemical species

Ac

Cross-sectional area (m2)

Ap

Total external surface area of particle (m2)

ap

External surface area of catalyst per unit bed volume (m2/m3)

a

Area of heat exchange per unit volume of reactor (m-1)

ac

External surface area per volume of catalyst pellets (m2/m3)

B

Chemical species

BA

Flux of A resulting from bulk flow (mol/m2 · s)

Bo

Bodenstein number

C

Chemical species

Ci

Concentration of species i (mol/dm3)

Cpi

Heat capacity of species i at temperature T (cal/gmol · K)

Image

Mean heat capacity of species i between temperature T0 and temperature T (cal/mol · K)

Image

Mean heat capacity of species i between temperature TR and temperature T (cal/mol · K)

c

Total concentration (mol/dm3) (Chapter 14)

D

Chemical species

Da

Damköhler number (dimensionless)

DAB

Binary diffusion coefficient of A in B (dm2/s)

Da

Dispersion coefficient (cm2/s)

De

Effective diffusivity (dm2/s)

DK

Knudsen diffusivity (dm2/s)

D*

Taylor dispersion coefficient

E

Activation energy (cal/gmol)

(E)

Concentration of free (unbound) enzyme (mol/dm3)

Fi

Molar flow rate of species i (mol/s)

Fi0

Entering molar flow rate of species i (mol/s)

G

Superficial mass velocity (g/dm2 · s)

Gi

Rate of generation of species i (mol/s)

Image

Gibbs free energy of species i at temperature T (cal/gmol · K)

Hi (T)

Enthalpy of species i at temperature T (cal/mol i)

Hi0 (T)

Enthalpy of species i at temperature T0 (cal/mol i)

Image

Enthalpy of formation of species i at temperature TR (cal/gmol i)

h

Heat transfer coefficient (cal/m2 · s · K)

JA

Molecular diffusive flux of species A (mol/m2 · s)

KA

Adsorption equilibrium constant

Kc

Concentration equilibrium constant

Ke

Equilibrium constant (dimensionless)

KP

Partial pressure equilibrium constant

k

Specific reaction rate (constant)

kc

Mass transfer coefficient (m/s)

Mi

Molecular weight of species i (g/mol)

mi

Mass of species i (g)

Ni

Number of moles of species i (mol)

n

Overall reaction order

Nu

Nusselt number (dimensionless)

Pe

Peclet number (Chapter 17)

Pi

Partial pressure of species i (atm)

Pr

Prandtl number (dimensionless)

Q

Heat flow from the surroundings to the system (cal/s)

R

Ideal gas constant

Re

Reynolds number

r

Radial distance (m)

rA

Rate of generation of species A per unit volume (gmol A/s·dm3)

rA

Rate of disappearance of species A per unit volume (mol A/s·dm3)

Image

Rate of disappearance of species A per mass of catalyst (mol A/g·s)

Image

Rate of disappearance of A per unit area of catalytic surface (mol A/m2·s)

S

An active site (Chapter 10)

(S)

Substrate concentration (gmol/dm3) (Chapter 7)

Sa

Surface area per unit mass of catalyst (m2/g)

SD/U

Instantaneous selectivity (Chapter 8)

Image

Overall selectivity of D to U

Sc

Schmidt number (dimensionless) (Chapter 10)

Sh

Sherwood number (dimensionless) (Chapter 10)

SV

Space velocity (s-1)

T

Temperature (K)

t

Time (s)

U

Overall heat transfer coefficient (cal/m2·s·K)

V

Volume of reactor (dm3)

V0

Initial reactor volume (dm3)

υ

Volumetric flow rate (dm3/s)

υ0

Entering volumetric flow rate (dm3/s)

W

Weight of catalyst (kg)

WA

Molar flux of species A (mol/m2·s)

X

Conversion of key reactant, A

Yi

Instantaneous yield of species i

Image

Overall yield of species i

y

Pressure ratio P/P0

yi

Mole fraction of species i

yi0

Initial mole fraction of species i

Z

Compressibility factor

z

Linear distance (cm)

Subscripts

0

Entering or initial condition

b

Bed (bulk)

c

Catalyst

e

Equilibrium

p

Pellet

Greek Symbols

α

Reaction order (Chapter 3)

α

Pressure drop parameter (Chapter 5)

αi

Parameter in heat capacity (Chapter 12)

βi

Parameter in heat capacity

β

Reaction order

γi

Parameter in heat capacity

δ

Change in the total number of moles per mole of A reacted

ε

Fraction change in volume per mole of A reacted resulting from the change in total number of moles

η

Internal effectiveness factor

Θi

Ratio of the number of moles of species i initially (entering) to the number of moles of A initially (entering)

λ

Dimensionless distance (z/L) (Chapter 15)

λ

Life expectancy (s) (Chapter 17)

μ

Viscosity (g/cm·s)

ρ

Density (g/cm3)

ρc

Density of catalyst pellet (g/cm3 of pellet)

ρb

Bulk density of catalyst (g/cm3 of reactor bed)

τ

Space time (s)

ϕ

Void fraction (Porosity)

ϕn

Thiele modulus

ψ

Dimensionless concentration (CA/CAs)

Ω

External (overall) effectiveness factor

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