CIP Cleaning in place

CIP
Cleaning in place
• The circulation of non foaming cleaners without dismantling
the equipment.
• An automatic and systematic cleaning of the inner
surfaces of tanks, heat exchangers, pumps, valves
and pipes.
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CIP properties
• Strong and hot solutions can be used. The heat, the
chemistry and the mechanics can be sustained
long.
• The solutions can be reused.
• Can be automated and reproducibility is good.
• Investment in equipment is high.
• The mechanics are not always sufficient
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Flow Rate vs. Flow Velocity
volume per second
1 second
inside diameter
v=
Where,
4.Q
2
3600.d .∏
v = flow velocity
Q = flow rate
π = pi (3.1415,…)
d = inside pipe diameter
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meters per second
m3 per hour
dimensionless
meters
Velocity vs flow
Pipe size
1.5 m/s velocity
2.0 m/s velocity
Litres / sec
Litres / sec
ID mm
DN 50
47
2.6
3.5
DN 80
77
6.9
9.3
DN 100
97
11.1
14.8
DN150
147
25.5
33.9
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Vertical vessel flow requirements - sprayballs
Vertical vessels
For most vessels, the sprayball delivers a uniform
quantity of solution to the upper circumference of the
vessel
Based on soil level, deliver a given quantity of solution
to a unit length of circumference - called liquid loading:
Don’t forget about flow OUT of vessels
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Sprayball Placement
 180 - Θ 
Depth of Sprayball = Dome Height + D ⋅ tan 

 2 
Depth of Sprayball
Dome Height
140º
Sprayball
Where,
θ = angle of coverage,
D = diameter of vessel,
Dome height
degrees
meters
meters
Dome Weld
NOTE: This is valid for simple
vessels without obstructions.
Additional sprayballs may be
required.
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example
100 gpm
15’
6” dia.
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Sprayball pressure
Sprayball pressure is critical
Generally in the range (1.0) 1.5 - 2.5 (3.0) bar
Too little pressure and the vessel walls are not reached
Too much and the spray atomises reducing mechanical
action
Larger sprayballs with larger hole diameters can operate
at higher pressures without atomising.
All sprayballs have specified flow / pressure curves
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Vertical vessel flow requirements - sprayballs
Flow as a function of diameter and soil
Q
R
=
D
QR = required flow rate
T
⋅ π
⋅ F
S
liters per minute
DT = vessel diameter
meters
p = pi (3.1415,…)
dimensionless
FS = soil factor
liters/(meter-minute)
FS = 27 for light soil conditions
FS = 30 for medium soil conditions
FS = 32 for heavy soil conditions
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High pressure rotary sprayheads
Add impingement to the mechanical action
Generally consume a little less water
Have specific times to wet surfaces and impinge on them dependent
on pressure and gearing
Not very effective on larger vessels under 5 bar pressure
Use similar data to specify as sprayballs
Use manufacturers recommendations
Toftejorg have a computer simulation
program called TRAX - use it
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CIP Optimizing
CIP optimizing is the process of minimizing the cost inputs of CIP
cleaning
water
effluent
energy
chemical
electrical
heat
CO2
production time
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Optimizing drivers
CIP system design
clean circuits - no dead legs, no flow splits
accurate and non competing instrumentation - conductivity
monitoring
no leaks
CIP program
correct CIP program philosophy
CIP preparation sequence - correct conductivity starting point
tidy CIP fluids interface management - always in lines never in
tanks
correct valve sequencing on monitor signals
defined terminators each CIP step
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CIP optimizing - circuit volume
To predict CIP losses and costs we must know the CIP circuit volume.
This has nothing to do with the size of the CIP tanks.
It is the amount of liquid held up in the CIP headers and the vessel or line being
cleaned.
To calculate the circuit volume for a line clean we need to know the diameters of
the lines and the length of each line size.
To calculate the circuit volume of a vessel clean we need to know the line
information and the dimensions of the vessel being cleaned.
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If there is other
too.
processing plant in the CIP circuit, we need to know it’s volume
Vessel Hold-up Volume
Assume a 2 millimeter film thickness
(0.002 m)
Dome
Assume a completely wetted surface
Determine internal surface area
Dome
Cylinder
Cone
Cylinder
Cone
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Vessel Hold-up Volume
Area of Dome:
Area of Cylinder:
Area Dome = π r
2
Area Cylinder = π D h2
D
h2
Area of Cone
h1
NOTE :
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(
)
1
2
2
Area Cone = D D + h1 2
4
π
r =
1
D
2
CIP optimizing - chemical loss management
Liquid loss for an efficient vessel CIP system is about 10% of circuit volume.
Line cleans can be run more efficiently than vessel cleans - as low as 5% loss.
Effective loss management depends on:
Effective Flow meter or conductivity interface detection.
Managing liquid interfaces into pipes not vessels.
When managing liquid changes in vessels the program must be stepped.
New liquid to sprayball chasing old liquid into vessel.
Over scavenge old liquid from vessel into return line.
New liquid into vessel chasing old along return line to interface
detector.
First step should be volumetric and set for each vessel.
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CIP optimizing - chemical loss management
measured as % of concentrate detergent lost compared to the concentrate
detergent in the CIP circuit volume
concentrate detergent lost is calculated by CIP tank, volume and
concentration, before and after CIP
concentrate detergent in circuit volume calculated as the volume of solution
held in the CIP circuit excluding the CIP tank at the starting concentration
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The CIP flow is best circulated bypassing the CIP tanks with the
heating and chemical dosing in line
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