لخّصلي

2.3.2Temperature Even though it is often expected to perform cleaning at room temperature, some indus- tries apply heating to increase the cleaning rate and to remove harsh deposits.Goode et al. (2013) found that the dependence of adhesive force on temperature was related to the types of deposits and surfaces.For whey protein concentrate deposits, the adhesive force became high after being heated to a temperature above 70 ?C due to the denaturation of proteins.On the contrary, caramel deposits turned to be less adhesive to stainless steel surfaces with temperature increasing from 30 to 90 ?C [44].For in- stance, changing water temperature from 22 to 45 ?C can improve the rinsing effectiveness significantly when flushing reconstituted skim milk from stainless steel pipes.Using high temperature in a cleaning process should be thoroughly considered along with the chem- ical effectiveness, system complexity, operating cost and risk, etc.Higher media temperature can increase the diffusion rate of chemicals and the reaction rate, henceforth improve the chemical effectiveness.

2.3.2Temperature
Even though it is often expected to perform cleaning at room temperature, some indus-
tries apply heating to increase the cleaning rate and to remove harsh deposits. Using high
temperature in a cleaning process should be thoroughly considered along with the chem-
ical effectiveness, system complexity, operating cost and risk, etc. Heating the cleaning
media and maintaining them at a certain temperature level is one of the biggest energy
consuming steps in a cleaning process [40].
Higher media temperature can increase the diffusion rate of chemicals and the reaction
rate, henceforth improve the chemical effectiveness. For example, pink guava puree fouling
cannot be effectively cleaned at 35 °C even with high NaOH concentration (up to 2.0
wt%). However, when the temperature is increased to 50 °C or 70 °C, fouling is removed
completely [41]. For yeast soil, an increase in temperature from 30 to 50 °C does not
decrease the cleaning time. However, chemical cleaning at 70 °C can shorten the cleaning
time greatly [42].
An extremely high temperature may sometimes make the cleaning unprofitable. For in-
stance, changing water temperature from 22 to 45 °C can improve the rinsing effectiveness
significantly when flushing reconstituted skim milk from stainless steel pipes. A further
increase to 67 °C only improves the cleaning rate slightly but increase the operating cost
hugely [43]. Furthermore, the increase in temperature can change the structure of de-
posits. Goode et al. (2013) found that the dependence of adhesive force on temperature
was related to the types of deposits and surfaces. For whey protein concentrate deposits,
the adhesive force became high after being heated to a temperature above 70 °C due
to the denaturation of proteins.On the contrary, caramel deposits turned to be less
adhesive to stainless steel surfaces with temperature increasing from 30 to 90 °C [44].
Another application of heating is to disinfect surfaces. For example, in the dairy industry,high temperature is often used after caustic and acid treatments to kill microorganisms
or decrease the microbe amount to a safe level.