1 Chapter 1
1 Chapter 1
1 Chapter 1
Chapter 1 : Introduction
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Chapter topics to be covered
1. Introduction
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1.1 Objectives
At end of this chapter students’ shall be able to:
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Fluid Machines in Chemical Process Industries
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Industrial application of fluid machines
Pumps are used to transport process and service liquids.
N QY N = QPt
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Cont’d
Equivalent
Term
Total Pressure
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Cont’d
Pulsation:-
The capacity of some fluid machines is not uniform, it
varies with time. Pulsation is this non uniformity of the
capacity fluid machines.
Priming:-
Some pumps require that the air in the suction line
should be replaced by liquid before they start
pumping. The process of replacing the air in the suction
pipe with liquid is known as priming.
Loss of Head:
is loss of the useful head of the flow medium due to
fluid friction or the turbulence that occurs when the
fluid passes an obstruction, sudden contraction or
sudden expansion, etc.
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Pressure
Absolute pressure (static) of a fluid on a surface is the
normal force exerted by the fluid per unit area of the surface.
Gauge Pressure is the pressure above the atmospheric
pressure.
Absolute Pressure = Gauge Pressure + Atmospheric Pressure
Vacuum Pressure is the pressure below the atmospheric
pressure.
Absolute Pressure = Atmospheric Pressure - Vacuum Pressure
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Mass balance for a steady state process (no accumulation)
Rate of mass input = Rate of mass output
1Q1 2Q2 ;
m 1 A1 c1 2 A2 c2
m
For incompressible fluid
A1c1 A2 c2
mass flow rate(kg/s)
Where :-Q=Volume flow rate [m3/s], m
C = velocity of the flow medium(m/s), A= Flow Area(m2)
A1 A2
Input output
Process
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Pump operation
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cont’d
The amount of specific energy required by a flow
medium
𝒄𝟐
Fmin, pipe= (∑Ki)
𝟐
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Fans
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Example 1.1
Water at 200C should be pumped from Tank 1 to Tank 2 at the rate of
120m3/hr. All pipes in the system are with diameter of 0.1541m. The
total length of the straight pipe is 45m. Determine the specific
mechanical energy, head and power that should be transferred to the flow
medium to move the water. (Use water at 200C ρ =998.2 kg/m3 , μ=1.005
*10-3 Pa. s; and pipe roughness, ε=4.6 *10 -5 ,k of 900 elbow =0.64)
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Example 1.2
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Compressors and blowers
Compressed air is one of the most common utility in process
industries.
e.g. it is used for most automatic control systems and for cleaning,
pneumatic conveying.
In liquefaction of gasses and process that depend on them (like
separation) compression is a very important step.
Various gas phase reactions that take place at high pressures are
also core in some chemical production, like ammonia production.
Types of Ideal
Compression
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Isothermal Compression
carried out under T=const
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Example 1.3
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