List of Nomenclature

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

D¯

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

f^i

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

k¯m

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, L¯

Liquid Flowrate (Over Bar signifies Below Feed in Distillation Column)

kg/s or kmol/s

m˙

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
NPSHR

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

 

Q˙

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

t¯

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

ut*

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, 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

v˙

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

W˙s

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

 

εr

Relative Permittivity of the Vapor Phase

 

εs

Permittivity of the Solvent

Columb2/kJ m

φ

Fugacity Coefficient

 

ϕ^

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

 

Overall Catalyst Effectiveness (Including Internal and External Resistances)

 

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

Table 1.2

Convention for Specifying Process Equipment

Table 1.3

Convention for Specifying Process Streams

Table 1.7

Abbreviations for Equipment and Materials of Construction

Table 1.10

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.

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