Page 149 - Chemical engineering design

FUNDAMENTALS OF ENERGY BALANCES
2 2 1
C p 2
2 2 1
Specific heat at constant volume
L T
C v Specific heat second phase L T q q 129
2 2 1
C o p Ideal gas state specific heat L T q
2 2 3
2 2 1/2
c Constant in specific heat equation (equation 3.13) L T q or L T q
2 2 1
CP c Sum of heat capacities of cold streams ML T q
2 2 1
CP h Sum of heat capacities of hot streams ML T q
E e Efficiency, electric motors
E p Polytropic efficiency, compressors and turbines
F Force MLT 2
g Gravitational acceleration LT 2
2 2
H Enthalpy ML T
2 2
H a Specific enthalpy of component a L T
2 2
H b Specific enthalpy of component b L T
2 3
H d Enthalpy top product stream (Example 3.1) ML T
2 3
H f Enthalpy feed stream (Example 3.1) ML T
2 2
H T Specific enthalpy at temperature T L T 2 3
H w Enthalpy bottom product stream (Example 3.1) ML T
2 2
H Change in enthalpy ML T
2 3
H cold Heat transfer from cold utility ML T
2 3
H ex Heat transfer in exchanger ML T
2 3
H hot Heat transfer from hot utility ML T
2 3
H n Heat available in nth interval ML T
2 2
H m,t Heat of mixing at temperature t L T
2 2
H r,t Heat of reaction at temperature t L T
H ° c Standard heat of combustion L T
2 2
H ° f Standard enthalpy of formation L T
2 2
H ° m Standard heat of mixing L T
2 2
H ° Standard heat of reaction L T
2 2
r
L Number of auxiliary streams, heat exchanger networks
L 0 Number of internal loops in network
l Distance L
M Number of hot streams, heat-exchanger networks
M Molecular mass (weight)
m Polytropic temperature exponent
m Mass M
m Mass flow-rate MT 1
N Number of cold streams, heat-exchanger networks
N 0 Number of streams
n Expansion or compression index (equation 3.30)
P Pressure ML 1 2
T
T
P i Inter-stage pressure ML 1 2
P r Reduced pressure
T
P 1 Initial pressure ML 1 2
P 2 Final pressure ML 1 T 2
2 3
2 2
Q Heat transferred across system boundary ML T or ML T
2 3
Q b Reboiler heat load (Example 3.1) ML T
2 3
Q c Condenser heat load (Example 3.1) ML T 2 3
2 2
Q p Heat added (or subtracted) from a system ML T or ML T
2 2
2 3
Q r Heat from reaction ML T or ML T
2 3
2 2
Q s Heat generated in the system ML T or ML T
2 2 1
R Universal gas constant L T q
S Number of independent branches
S cj Cold streams, heat-exchanger networks
S hi Hot streams, heat-exchanger networks
S uk Auxiliary streams, heat-exchanger networks
T Temperature, absolute q
T act Actual stream temperature q