Page 66 - FoodFocusThailand No.214 JANUARY 2024

SOURCE OF ENGINEER

Other than simulation, scaling up only key parts of the Case Study: Scaling Up Cyclone Equipment
equipment with data uncertainty or unknown parameters In case that the scaling-up relationship has been previously
could be done to check the results instead of scaling up the and obviously developed, for machines employing
entire system or unit operation to save cost. straightforward and uncomplicated processes, the process of
Two key points to specify in the production process scaling up these machines, for example, the Cyclone that is
and unit operation’s design and scale-up are required the machine for solid particle separation from the medium’s
process parameters and process results. For example, flow steam, is unlikely to be challenging, as demonstrated in
specify the process parameters such as temperature, Figure 2:
pressure, concentration, flow rate, speed, power, torque, The following is the scaling-up equation for Cyclone, the
shear rate, dimensionless number, strain, circulation rate, machine separating solid particles from the medium’s flow
superficial velocity, etc. The designer could freely choose steam.
the required results for the process, such as reaction rate,
mass transfer, heat transfer, dimensionless number, odor,
taste, texture, and overall acceptability. Basic measurements
like temperature, pressure, concentration, flow rate, and
speed are also considered as required parameters.

Criteria Before Scaling Up the Production in When d is the average diameter of particles that was
Food Industry separated in the standard condition and the separating
There are two criteria for scaling up the unit operation: efficiency was chosen for the standard-sized Cyclone (d ) and
1
Primary scale-up criterion, which is the consideration of the new design Cyclone (d ).
2
a parameter or set of parameters for the process resulting D is the diameter of the standard-sized Cyclone (8 inches)
C
in the desired process, where those parameters do not (D ) and the new design Cyclone (D )
C2
C1
depend on the process’s scale or size. Those parameters Q is the flow rate of the air current of the standard-sized
may be the key parameters to design tools and equipment Cyclone (Q ) and the new design Cyclone (Q ) (m /h) (For
3
2
1
on any scale, for example, friction coefficients or dimensionless high-efficient Cyclone = 223 m /h)
3
friction factors related to the Reynolds number in the Moody is the difference in density between a solid object and
diagram as specified in Figure 1. In this case, the process a gas current or fluid that transports solid particles in in the
parameter is Reynolds number, which is true for pipe in every standard condition ( ) and the new-design size ( )
size. is the viscosity of fluid in the experimentation ( ) and
Furthermore, another example of an actual relationship the fluid used in the new design Cyclone ( ). (The viscosity
.
of all-size machines is the dimensionless number relationship of air at 20 C and pressure 1 atm = 0.018 mN s/m )
o
2
in heat transfer, Nu = f(Re, Pr), where the Nusselt number It indicated that if there was a specific scaling-up equation
has a related function with the Reynolds number and the for machines, as demonstrated in the Cyclone example,
Prandtl number. This relationship was explained by many scaling up to determine the scale-up factor would be
equations, which varied depending on the case, but the simple.
parameter would always be the actual value regardless of Scaling up is a challenging task that food technologists
scale. In this case, the Nusselt number, a result of and processing engineers must confront. Unfortunately, food
processing, is a method of explaining heat flux that was science and technology courses have not thoroughly covered
exchanged in many cases. Scaling up will be defined by the this topic. The operator’s knowledge and expertise in this field
Nusselt and Prandtl numbers’ functions because almost all need to be developed through hands-on experience with
correlations of this type were generated directly from the problems during work. It might be the outcome of variations
experiment results. in the mechanics of physics or in chemical processes not
The secondary scale-up criterion is another criterion being fully recognized in connection with a process in the
under consideration. This criterion considers the physical production scales at multiple levels. In many cases, the
and mechanical changes that occurred as a result of machine operator was required to conduct the experiments on their
size and production scale. They need to be understood to own, while it was recommended that, if at all possible, the
apply this criterion to the primary scale-up criterion, for which experiments should be conducted in an orthogonal design
the designer needs to acquire an understanding of these using parameters and dimensionless numbers from the start.
parameters, such as the impact of scaling up on heat This was because the experiment was developed using basic
exchange, the impact of scaling up on horsepower or torque, parameters such as power, temperature, size, mass, pressure,
etc., to scale up the production process correctly. or time. These parameters were later included to be
Therefore, to scale up the processing accurately, the dimensionless numbers; the relationship would be inaccurate
designer must consider the following: a) Establishing the and more challenging to interpret compared to the experimental
expected results. b) Determining the primary scale-up result obtained with the dimensionless numbers initially
criterion, a parameter or set of parameters ensuring the employed.
expected result of the processing remains constant
regardless of the process’s scale, necessitating
experimentation across multiple scale levels; and More Information Service Info C010
c) Determining the secondary scale-up criterion.

66 FOOD FOCUS THAILAND JAN 2024

22/12/2566 BE 09:26
61-65_Source of engineer_�.����.indd 66 22/12/2566 BE 09:26
61-65_Source of engineer_�.����.indd 66