Pocket Guide to Chemical Engineering by Carl R. Branan Notes | EduRev

: Pocket Guide to Chemical Engineering by Carl R. Branan Notes | EduRev

 Page 1


Pocket Guide to Chemical Engineering 
by Carl R. Branan 
 
 
 
 
•  ISBN: 0884153118 
•  Pub. Date: November 1999  
•  Publisher: Elsevier Science & Technology Books 
Page 2


Pocket Guide to Chemical Engineering 
by Carl R. Branan 
 
 
 
 
•  ISBN: 0884153118 
•  Pub. Date: November 1999  
•  Publisher: Elsevier Science & Technology Books 
Introduction 
This pocket guide contains selected rules of thumb and 
shortcut design methods meant to travel into the field as 
well as the office, even when the "office" is a hotel room. It 
contains updates on certain fast-moving technology and 
new material not found elsewhere. Miniaturization and easy 
retrieval of information are stressed. Those on the go can 
produce reasonable results quickly when using this book as 
a basic source. 
Carl Branan 
E1 Paso, Texas 
Page 3


Pocket Guide to Chemical Engineering 
by Carl R. Branan 
 
 
 
 
•  ISBN: 0884153118 
•  Pub. Date: November 1999  
•  Publisher: Elsevier Science & Technology Books 
Introduction 
This pocket guide contains selected rules of thumb and 
shortcut design methods meant to travel into the field as 
well as the office, even when the "office" is a hotel room. It 
contains updates on certain fast-moving technology and 
new material not found elsewhere. Miniaturization and easy 
retrieval of information are stressed. Those on the go can 
produce reasonable results quickly when using this book as 
a basic source. 
Carl Branan 
E1 Paso, Texas 
1 Fluid Flow 
GENERAL 
Two of the most useful and basic equations are 
2 U Ah=~ 
2g 
(1-1) 
Au 2 AP (V) + ~ + AZ + E=0 (1-2) 
2g 
where Ah = head loss in feet of flowing fluid 
u - velocity in ft/sec 
g = 32.2 ft/sec 2 P = pressure in lb/ft 2 V = specific volume in ft3/lb 
Z = elevation in feet 
E = head loss due to friction in feet of flowing fluid 
Page 4


Pocket Guide to Chemical Engineering 
by Carl R. Branan 
 
 
 
 
•  ISBN: 0884153118 
•  Pub. Date: November 1999  
•  Publisher: Elsevier Science & Technology Books 
Introduction 
This pocket guide contains selected rules of thumb and 
shortcut design methods meant to travel into the field as 
well as the office, even when the "office" is a hotel room. It 
contains updates on certain fast-moving technology and 
new material not found elsewhere. Miniaturization and easy 
retrieval of information are stressed. Those on the go can 
produce reasonable results quickly when using this book as 
a basic source. 
Carl Branan 
E1 Paso, Texas 
1 Fluid Flow 
GENERAL 
Two of the most useful and basic equations are 
2 U Ah=~ 
2g 
(1-1) 
Au 2 AP (V) + ~ + AZ + E=0 (1-2) 
2g 
where Ah = head loss in feet of flowing fluid 
u - velocity in ft/sec 
g = 32.2 ft/sec 2 P = pressure in lb/ft 2 V = specific volume in ft3/lb 
Z = elevation in feet 
E = head loss due to friction in feet of flowing fluid 
2 Pocket Guide to Chemical Engineering 
In Equation 1-1 Ah is called the "velocity head." This 
expression has a wide range of utility not appreciated by 
many. It is used "as is" for 
1. Sizing the holes in a sparger 
2. Calculating leakage through a small hole 
3. Sizing a restriction orifice 
4. Calculating the flow with a pitot tube 
With a coefficient it is used for 
1. Orifice calculations 
2. Relating fitting losses 
3. Relief valve sizing 
4. Heat exchanger tube leak calculations 
For a sparger consisting of a large pipe having small 
holes drilled along its length, Equation 1-1 applies directly. 
This is because the hole diameter and the length of fluid 
travel passing through the hole are similar dimensions. An 
orifice, on the other hand, needs a coefficient in Equation 1- 
1 because hole diameter is a much larger dimension than 
length of travel (say ~ in. for many orifices). Orifices will 
be discussed under "Metering" later in this chapter. 
For compressible fluids one must be careful that when 
sonic or "choking" velocity is reached, further decreases in 
downstream pressure do not produce additional flow. This 
occurs at an upstream to downstream absolute pressure 
ratio of about 2:1. Critical flow due to sonic velocity has 
practically no application to liquids. The speed of sound in 
liquids is very high. See "Sonic Velocity" in this chapter. 
Page 5


Pocket Guide to Chemical Engineering 
by Carl R. Branan 
 
 
 
 
•  ISBN: 0884153118 
•  Pub. Date: November 1999  
•  Publisher: Elsevier Science & Technology Books 
Introduction 
This pocket guide contains selected rules of thumb and 
shortcut design methods meant to travel into the field as 
well as the office, even when the "office" is a hotel room. It 
contains updates on certain fast-moving technology and 
new material not found elsewhere. Miniaturization and easy 
retrieval of information are stressed. Those on the go can 
produce reasonable results quickly when using this book as 
a basic source. 
Carl Branan 
E1 Paso, Texas 
1 Fluid Flow 
GENERAL 
Two of the most useful and basic equations are 
2 U Ah=~ 
2g 
(1-1) 
Au 2 AP (V) + ~ + AZ + E=0 (1-2) 
2g 
where Ah = head loss in feet of flowing fluid 
u - velocity in ft/sec 
g = 32.2 ft/sec 2 P = pressure in lb/ft 2 V = specific volume in ft3/lb 
Z = elevation in feet 
E = head loss due to friction in feet of flowing fluid 
2 Pocket Guide to Chemical Engineering 
In Equation 1-1 Ah is called the "velocity head." This 
expression has a wide range of utility not appreciated by 
many. It is used "as is" for 
1. Sizing the holes in a sparger 
2. Calculating leakage through a small hole 
3. Sizing a restriction orifice 
4. Calculating the flow with a pitot tube 
With a coefficient it is used for 
1. Orifice calculations 
2. Relating fitting losses 
3. Relief valve sizing 
4. Heat exchanger tube leak calculations 
For a sparger consisting of a large pipe having small 
holes drilled along its length, Equation 1-1 applies directly. 
This is because the hole diameter and the length of fluid 
travel passing through the hole are similar dimensions. An 
orifice, on the other hand, needs a coefficient in Equation 1- 
1 because hole diameter is a much larger dimension than 
length of travel (say ~ in. for many orifices). Orifices will 
be discussed under "Metering" later in this chapter. 
For compressible fluids one must be careful that when 
sonic or "choking" velocity is reached, further decreases in 
downstream pressure do not produce additional flow. This 
occurs at an upstream to downstream absolute pressure 
ratio of about 2:1. Critical flow due to sonic velocity has 
practically no application to liquids. The speed of sound in 
liquids is very high. See "Sonic Velocity" in this chapter. 
Fluid Flow 3 Still more mileage can be obtained from Ah - u2/2g 
when using it with Equation 1-2, which is the famous 
Bernoulli equation. The terms are 
1. The PV change 
2. The kinetic energy change or "velocity head" 
3. The elevation change 
4. The friction loss 
These contribute to the flowing head loss in a pipe. Howev- 
er, there are many situations where by chance, or on pur- 
pose, u2/2g head is converted to PV or vice versa. 
We purposely change u2/2g to PV gradually in the fol- 
lowing situations: 
1. Entering phase separator drums to cut down turbu- 
lence and promote separation 
2. Entering vacuum condensers to cut down pressure 
drop 
We build up PV and convert it in a controlled manner to 
u2/2g in a form of tank blender. These examples are dis- 
cussed under appropriate sections. 
PIPING PRESSURE DROP 
A handy relationship for turbulent flow in commercial 
steel pipes flowing full is: 
AP F -- Wl.8~to.2/20,000d4.Sp (~-3) 
Read More
Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!