Symbol |
Definition |
SI Units |
a |
Stoichiometric Coefficient |
|
a |
Interfacial, Mass Transfer Area |
m2 |
a |
Mean Ionic Diameter of an Electrolyte |
m |
a′ |
Interface Area per Unit Volume |
m2/m3 |
A |
Equipment Cost Attribute |
|
A |
Area, Heat Transfer Surface Area |
m2 |
A |
Absorption Factor |
|
A |
Annuity Value |
$/time |
A |
Constant in Antoine’s Equation |
|
A/F, i, n |
Sinking Fund Factor |
|
A/P, i, n |
Capital Recovery Factor |
|
Ab |
Bubbling Area |
m2 |
Ac |
Cross-Sectional Area |
m2 |
At |
Total Cross-Sectional Area of Packed Bed |
m2 |
b |
Fin Spacing |
m |
B |
Constant in Antoine’s Equation |
°C |
BC |
Baffle Cut (% of Shell Diameter) |
|
Bo |
Boiling Number |
|
BV |
Book Value |
$ |
C |
Constant in Antoine’s Equation |
°C |
C |
Molar Density |
mol/m3 |
C |
Equipment Cost |
$ |
C or c |
Molar Concentration |
kmol/m3 |
Csb,f |
Parameter in Flooding Calculation |
m/s |
CA |
Corrosion Allowance |
m |
CBM |
Bare Module Cost |
$ |
CD |
Drag Coefficient |
|
Cf |
Material Constant for Surfaces Used in Boiling Heat Transfer |
|
COM |
Cost of Manufacture |
$/time |
cop |
Coefficient of Performance |
|
Cp, Cv |
Heat Capacities (Constant Pressure, Constant Volume) |
kJ/kg°C or kJ/kmol°C |
CCP |
Cumulative Cash Position |
$ |
CCR |
Cumulative Cash Ratio |
|
D, DAB |
Diffusivity, Diffusion Coefficient of Solute A in Solution B |
m2/s |
d, D |
Diameter |
m |
D* |
Dimensionless Diameter |
|
D |
Amount Allowed for Depreciation |
$ |
D |
Distillate Product Flowrate |
kmol/time |
d |
Yearly Depreciation Allowance |
$/yr |
DCFROR |
Discounted Cash Flow Rate of Return |
|
DMC |
Direct Manufacturing Cost |
$/time |
DPBP |
Discounted Payback Period |
years |
Average Diffusivity |
m2/s |
|
D0 |
Diffusivity at Infinite Dilution |
m2/s |
Dp, DS |
Particle Diameter, Sphere Diameter |
m |
d |
Vector of Disturbance Inputs |
|
ds |
Average Solvent Density |
kg/m3 |
e |
Elementary Charge |
Columb |
e |
Pipe Roughness Factor |
m |
ef |
Energy Dissipated by Friction |
J/kg |
E |
Money Earned |
$ |
E |
Weld Efficiency |
|
E(t) |
Residence Time Distribution in Reactor |
s-1 |
Eact or E |
Activation Energy |
kJ/kmol |
Eo |
Overall Column Efficiency |
|
EAOC |
Equivalent Annual Operating Cost |
$/yr |
ECC |
Equivalent Capitalized Cost |
$ |
f |
Fraction of Stream |
|
f, |
Friction Factor |
|
f |
Rate of Inflation |
|
f |
Factor Used in Convective Boiling Correlation |
|
fq |
Quantity Factors for Trays |
|
F |
Faraday’s Constant |
Columb/kmol |
F |
Future Value |
$ |
F |
Molar Flowrate |
kmol/s, kmol/h |
F |
Equipment Module Cost Factor |
|
F |
Correction for Multipass Heat Exchangers |
|
F |
Force |
N |
F |
Packing Factor in Packed Beds |
|
Flv |
Parameter in Flooding Calculation |
|
Fd, Fg, Fp |
Drag, Gravitational, and Pressure Force |
N/m2 or kPa |
Fx, Fy |
Mass Transfer Coefficients for Liquid (x) or Vapor (y) Phase |
m/s |
F/A, i, n |
Uniform Series Compound Amount Factor |
|
FCI |
Fixed Capital Investment |
$ |
F/P, i, n |
Single Payment Compound Amount Factor |
|
FMC |
Fixed Manufacturing Costs |
$/time |
FLang |
Lang Factor |
|
fi |
Fugacity of Pure Component i |
bar or kPa |
Fugacity of Component i in Mixture |
bar or kPa |
|
f |
System of Equations (vector) |
|
g |
Acceleration Due to Gravity |
m/s2 |
gc |
Unit Conversion of 32.2 ft lb/lbf/sec2 |
ft lb/lbf/sec2 |
G, G′ |
Superficial Mass Velocity |
kg/m2/s |
G |
Gibbs Free Energy |
kJ |
G |
Gas Flowrate |
kg/s, kmol/s |
GE |
General Expenses |
$/time |
h |
Individual Heat Transfer Coefficient |
W/m2/K |
H, HA |
Henry’s Law Constant |
bar or kPa in Equation (13.5), but can be different elsewhere |
H, h |
Enthalpy, Specific Enthalpy |
kJ or kJ/kg |
H or h |
Height or Head |
m |
H, HTU |
Height of Transfer Unit |
m |
HETP |
Height Equivalent of a Theoretical Plate |
m |
hf |
Height of Froth on a Tray |
m |
hmf |
Bed Height at Minimum Fluidization |
m |
I |
Identity Matrix |
|
I |
Ionic Concentration |
kmol/m3 |
Ix |
Ionic Strength on a Mole Fraction Basis |
|
I |
Cost Index |
|
i |
Compound Interest |
|
i′ |
Effective Interest Rate Including Inflation |
|
INPV |
Incremental Net Present Value |
$ |
IPBP |
Incremental Payback Period |
years |
J |
Jacobian Matrix |
|
k |
Thermal Conductivity |
W/m K |
k |
Ratio of Specific Heat Capacities of a Gas |
|
ko, K |
Preexponential Factor for Reaction Rate Constant |
Depends on molecularity of reaction |
K |
Loss Coefficient for Elbows, Fittings, etc. |
|
Kp |
Equilibrium Constant |
Depends on reaction stoichiometry |
kB |
Boltzmann Constant |
kJ/K |
Average Mass Transfer Coefficient |
m/s |
|
kreac or ki |
Reaction Rate Constant |
Depends on molecularity of reaction |
kSB |
Souders-Brown Constant |
m/s |
K |
Geometric Factor for Elliptical Heads |
|
Kc |
Proportional Gain |
|
Kcu |
Ultimate Controller Gain |
|
Keq |
Equilibrium Constant of a Chemical Reaction |
|
Ki |
Vapor-Liquid Equilibrium Ratio of Species i |
|
Kx, Ky |
Mass Transfer Coefficient (x is Liquid Phase, y is Vapor Phase) |
kmol/m2/s |
L |
Lean Stream Flowrate |
kg/s |
L |
Length (also Baffle Spacing), Characteristic Length of a Catalyst Particle |
m |
Leq |
Equivalent Length of Pipe |
m |
L, |
Liquid Flowrate (Over Bar signifies Below Feed in Distillation Column) |
kg/s or kmol/s |
Mass Flowrate |
kg/s |
|
m |
Equilibrium/Partition Coefficient (y/x) |
|
m |
Molality |
kmol/kg |
m |
Parameter Used in Fin Effectiveness, m = (2h / δk)1/2 for Rectangular Fins, etc. |
|
m, M |
Ratio of Tube Side and Shell Side Flows in Performance Problems |
|
M, mw |
Molecular Weight |
kg/kmol |
M |
Mass |
kg |
M |
Stress Intensity Factor for Dished Heads |
|
MT |
Thiele Modulus |
|
n |
Life of Equipment |
years |
n |
Years of Investment |
years |
n |
Number of Batches |
|
nc |
Number of Campaigns |
|
N |
Number of Streams, Trays, Stages, Transfer Units, Shells, etc. |
|
Nu |
Nusselt Number |
|
N |
Molar Flowrate or Molar Flux |
kmol/s or kmol/m2/s |
NPSHA |
Net Positive Suction Head (Available, Required) |
m of liquid (or Pa) |
NPV |
Net Present Value |
$ |
NtoG |
Number of Transfer Units |
|
N |
Molar Holdup |
kmol |
OBJ, OF |
Objective Function |
usually $ or $/time |
p |
Tube Pitch (Distance between Centers of Adjacent Tubes) |
m |
p |
Price |
$ |
pi |
Partial Pressure |
Pa |
P |
Dimensionless Temperature Approach Used in Log-Mean Temperature Correction Factor |
|
P, p |
Pressure and Partial Pressure |
bar or kPa |
P |
Present Value |
$ |
P* |
Vapor Pressure |
bar or kPa |
Pi |
Membrane Permeability of Component i |
m3/m2/s/kPa |
P/A, i, n |
Uniform Series Present Worth Factor |
|
PBP |
Payback Period |
year |
PC |
Project Cost |
$ |
P/F, i, n |
Single Payment Present Worth Factor |
|
PVR |
Present Value Ratio |
|
P(x) |
Probability Density Function of x |
|
Pr |
Prandtl Number |
|
Pu |
Ultimate Period of Oscillation |
s |
Q or q |
Rate of Heat Transfer or Heat Duty |
W or MJ/h |
q |
Fraction of Liquid in Distillation Column Feed |
|
Heat Transfer Rate |
W or MJ/h |
|
r |
Radius |
m |
r |
Reaction Rate |
kmol/m3 or kmol/kg cat s |
r |
Rate of Production |
kg/h |
rk |
Knuckle Radius for Dished Heads |
m |
R |
Gas Constant |
kJ/kmol K |
R |
Ratio of Heat Capacities Used in Log-Mean Temperature Correction Factor |
|
R |
Residual Funds Needed |
$ |
R |
Reflux Ratio |
|
R |
Heat Transfer Resistance |
m2K/W |
R |
Restoring Force to Keep Elbow (pipe fitting) Stationary |
N |
Re |
Reynolds Number |
|
Reemf |
Reynolds Number at Minimum Fluidization |
|
Ret |
Reynolds Number at Terminal Velocity |
|
R |
Rich Stream Flowrate |
kg/s |
Rand |
Random Number |
|
ROROI |
Rate of Return on Investment |
% p.a. |
ROROII |
Rate of Return on Incremental Investment |
% p.a. |
s |
Suppression Factor Used in Convective Boiling Correlation |
|
S |
Entropy |
kJ/K |
S |
Salvage Value |
$ |
S |
Maximum Allowable Working Pressure |
bar |
S |
Salt Concentration Factor |
|
S |
Sensitivity |
|
S |
Interfacial Surface Area |
m2 |
S |
Stripping Factor |
|
SF |
Stream Factor |
|
t |
Thickness of Wall |
m |
t |
Time |
s, min, h, yr |
Average Time Spent in Reactor |
s |
|
tm |
Membrane Thickness |
m |
Tm |
Melting Temperature |
K |
T |
Total Time for a Batch |
s, min, h, yr |
T |
Temperature |
K, R, °C, or °F |
U |
Internal Energy |
kJ |
u |
Vector of Manipulated Inputs |
|
u |
Flow Velocity |
m/s |
Dimensionless Terminal Velocity |
|
|
us |
Superficial Velocity in Packed or Fluidized Bed |
m/s |
ut |
Terminal Velocity of a Particle |
m/s |
U |
Overall Heat Transfer Coefficient |
W/m2K |
U |
Internal Energy |
J |
v |
Molar Volume |
m3/mol |
V |
Volume |
m3 |
V, |
Vapor Flow Rate (Over Bar is Below Feed in Distillation Column) |
kmol/h |
vreact |
Specific Volume of Reactor |
m3/kg of product |
vp |
Velocity |
m/s |
Volumetric Flowrate |
m3/s |
|
W |
Weight |
kg |
W |
Total Moles of a Component |
kmol |
W |
Width of Heat Transfer Fin |
m |
W or WS |
Work or Shaft Work |
kJ/kg |
Shaft Power |
W |
|
WC |
Working Capital |
$ |
X |
Matrix of Independent Variables |
|
x |
Vector of Variables |
|
x |
Mole or Mass Fraction |
|
x |
Wall or Film Thickness |
m |
x |
Mole Faction in Liquid Phase |
|
X |
Conversion |
|
X |
Base-Case Ratio |
|
Xtp |
Martinelli’s Two-Phase Flow Parameter |
|
y |
Mole or Mass Fraction (in Vapor Phase) |
|
Y |
Yield |
|
YOC |
Yearly Operating Cost |
$/yr |
YS |
Yearly Cash Flow (Savings) |
$/yr |
z |
Valence of Ions |
|
z |
Solids Mole Fraction, Mole Fraction in Feed Stream |
|
z |
Distance or level |
m |
z |
Coordinate in Direction Opposite Gravity |
M |
Greek Symbols
α |
Multiplication Cost Factor |
|
αAB |
Relative Volatility or Relative Permeability (between Species A and B) |
|
α |
NRTL Nonrandomness Factor |
|
α |
Parameter in Calculating Pressure Drop in Packed Bed |
|
β |
Parameter in Calculating Pressure Drop in Packed Bed |
|
β |
Orifice Diameter/Pipe Diameter |
|
δ |
Thickness of the Ion-Free Layer below |
|
δ |
(Condensing) Film Thickness or Fin Thickness |
m |
ε |
Void Fraction |
|
ε |
Pump Efficiency |
|
ε |
Tolerance, Error |
|
ε |
Emissivity |
|
ε |
Effectiveness (for fins) |
|
εij |
Lennard-Jones Energy Parameter between Species i and j |
kJ/kmol |
εr |
Relative Permittivity of the Solvent |
|
Relative Permittivity of the Vapor Phase |
|
|
εs |
Permittivity of the Solvent |
Columb2/kJ m |
φ |
Fugacity Coefficient |
|
Fugacity Coefficient in Mixture |
|
|
φ* |
Fugacity Coefficient of Saturated Vapor |
|
γ |
Activity Coefficient |
|
γ |
Ratio of Heat Capacities = Cp/Cv |
|
γ∞ |
Activity Coefficient in the Mixture at Infinite Dilution |
|
γ± |
Mean Ionic Activity Coefficient |
|
κ |
Inverse of Debye-Hückel Length |
m–1 |
η |
Catalyst Effectiveness Factor |
|
η |
Selectivity |
|
η, ηc, ηf, ηp, ηt |
Efficiency for Compressor, Separator, Pump, Turbine |
|
λ |
Heat of Vaporization |
kJ/kg |
λ |
Eigenvalue |
|
λ |
Heat of Vaporization/Condensation |
kJ/kg |
λ |
Lagrangian Multiplier Vector |
|
λ0 |
Thermal Conductivity of Pure Solvent |
W/m K |
μ |
Viscosity |
kg/m s |
μc |
Chemical Potential |
kJ |
μ0 |
Viscosity of Pure Solvent |
kg/m s |
ν |
Stoichiometric Coefficient |
|
θ |
Parameter Vector |
|
θ |
Ratio of Species Concentration to That of Limiting Reactant |
|
θ |
Angle |
° or rad |
θ |
Stage Cut in Gas Permeation Membrane |
|
σ |
Statistical Variance |
|
σ |
Collision Diameter |
m |
σ |
Surface Tension |
N/m (dyne/cm2) |
σ |
Stefan-Boltzmann Constant |
W/m2/K4 |
ξ |
Selectivity |
|
ρ,ρs |
Density, Solid (Particle) Density |
kg/m3 |
Θ |
Stoichiometric Parameter |
|
Θ |
Cycle Time |
s |
τ |
Space Time |
s |
τ |
NRTL Binary Interaction Energy Parameter |
|
τD |
Derivative Time Constant |
s |
τI |
Integral Time Constant |
s |
ψ |
Density of Water/Density of Liquid in Packed Bed |
|
Ψ |
Sphericity |
|
Ψ |
Inertial Separation Parameter |
|
Ω |
Overall Catalyst Effectiveness (Including Internal and External Resistances) |
|
Ω |
Collision Integral |
Subscripts
1 |
Base Time, Base Case, or Inlet Condition |
2 |
Desired Time, New Case, or Outlet Condition |
a |
Required Attribute |
air-leak |
Air Leak Due to Vacuum Conditions |
A, B, R, S |
Designating Components A, B, R, S |
ACT, actual |
Actual |
Active |
Refers to Active Column Area |
Aux |
Auxiliary Buildings |
a, a′ |
Anion |
b |
Base Attribute, Baffle |
b |
Bulk or Bubble Phase |
bare |
Bare Fin |
base |
Fin Base |
B |
Bottoms of Distillation Column |
BM |
Bare Module |
c, c′ |
Cation |
c |
Cold, Corrected, Critical, Coolant |
cb |
Convective Boiling |
cat |
Catalyst |
clean |
Cleaning |
cocurrent |
Designating a Cocurrent Arrangement for an S-T Heat Exchanger |
countercurrent |
Designating a Countercurrent Arrangement for an S-T Heat Exchanger |
Cont |
Contingency |
C |
Refers to Condenser |
cv |
Control Volume |
cw |
Cooling Water |
cycle |
Cycle |
d |
Without Depreciation |
dished |
Dished Vessel Head |
elliptical |
Elliptical Vessel Head |
D, d |
Demand |
D |
Distillate |
E |
Emulsion Phase |
E |
Contractor Engineering Expenses |
eff |
Effective |
eq |
Equivalent |
el |
Electrolyte(s) |
eq |
Metal in the Equipment |
f |
Flooding Conditions |
fb |
Film Boiling |
fin |
Fin |
film |
Film |
F,f |
Feed |
Fee |
Contractor Fee |
FTT |
Transportation, etc. |
g |
Gas |
GR |
Grass Roots |
h |
Hot |
H |
Hydraulic |
i |
Species |
i |
Index, Inside, or Interface |
in |
Inlet or Inner |
int |
Internal |
k |
Year |
lm |
Log-Mean |
l-h |
Liquid Holdup |
l, L |
Liquid |
L |
Installation Labor |
L |
Lean Streams |
L |
Without Land Cost |
LF |
Long-Range Force |
m |
Molality Scale |
m |
Mass Transfer |
m |
Molecular Species |
m |
Heating/Cooling Medium or Membrane |
m |
Number of Years |
M |
Materials for Installation |
M |
Material Cost Factor |
max |
Maximum |
MC |
Matching Costs |
mesh |
Mesh |
min |
Minimum |
n |
Index for Time Instant |
nom |
Nominal Interest |
o |
Outside |
out |
Outlet |
O or OH |
Construction Overhead |
Off |
Offsites and Utilities |
OL |
Operating Labor |
OL, OV, ov |
Overall Liquid and Overall Vapor Transfer Units or Height of Transfer Unit, Respectively |
opt |
Optimum |
p |
Production |
p |
Process Stream or Permeate Stream |
pb |
Pool Boiling |
P |
Equipment at Manufacturer’s Site (Purchased), Pressure Cost Factor, Process or Particle |
P&I |
Piping and Instrumentation |
rev |
Reversible |
rxn, r |
Reaction |
r |
Reduced (Pressure) |
r |
Retenate Stream |
rad |
Radiation |
R |
Rich Stream, Reboiler, Reference |
RM |
Raw Materials |
s |
All Nonwater Solvents, Simple Interest, Surface, or Stream |
sat |
Saturated |
s, shell |
Shell (Side) of Heat Exchanger |
S |
Supply |
SB |
Souders-Brown |
Site |
Site Development |
SF |
Short-Range Force |
sph |
Spherical or Equivalent Spherical |
t, tube |
Tube (Side) of Heat Exchanger |
t |
Terminal |
tp |
Tube Passes |
TM |
Total Module |
UT |
Utilities |
V, v |
Vapor |
vap |
Vaporization |
ves |
Vessel |
wire |
Wire |
WT |
Waste Treatment |
w |
Water or Wall |
y |
Designation for Type in Effectiveness Factor for Heat Exchangers, y = 1-2, 2-4, 3-6, etc. |
z |
Distance Along Reactor or Tube |
+ |
Cation |
– |
Anion |
Superscripts
α, β |
Powers of Coefficients in Langmuir-Hinshelwood Kinetics |
a, b |
Powers in Simple Rate Laws |
DB |
Double Declining Balance Depreciation |
E or ex |
Excess Property |
L |
Lower Limit |
L, l |
Liquid |
* |
Equilibrium Value |
o |
Cost for Ambient Pressure Using Carbon Steel |
s |
Solid |
SL |
Straight Line Depreciation |
SOYD |
Sum of the Years Depreciation |
U |
Upper Limit |
v |
Vapor |
∞ |
Aqueous Infinite Dilution |
′ |
Includes Effect of Inflation on Interest |
′′′ |
Signifies Reaction Rate Per Unit Mass of Catalyst |
Additional Nomenclature
Convention for Specifying Process Equipment |
|
Convention for Specifying Process Streams |
|
Abbreviations for Equipment and Materials of Construction |
|
Convention for Specifying Instrumentation and Control Systems |
Note: In this book, matrices are denoted by boldface, uppercase, italicized letters and vectors are denoted by boldface, lowercase, italicized letters.
3.144.193.129