Dairy processing industry has two basic and very important operations.
1- Processing of product
2- CIP- Clean in place
CIP – Cleaning in place
Annoyingly in a dairy processing industry, CIP parameters and interlocking are much more important than product processing. The reason is, if we design a CIP sub-standard circuit, it ultimately vandalize the product. To ensure the CIP parameter up to the mark, the terminology of 4Ts are followed globally.
4Ts of CIP means:
1- Titration (Concentration)
2- Turbulence (Velocity)
Titration means the concentration of caustic and acid. During CIP, the concentration of solution should be in range. Reduction in concentration going to impact on cleaning.
Saponification is a process of making soap by agitating caustic soda and fats. The same idea is been used in CIP, to the catalytic that reaction turbulence is required. The velocity of fluid during CIP should be 1.5m/s to 2.5m/s. below and above the standard values also disturbs the aim of this operation.
Time and temperature are also as much important as titration and turbulence.
Engineering design to follow while designing a CIP circuit
Some important aspects of engineering design considerations are:
Dead ends of any pipe should not be greater than 1.5X of its dia. The important point to follow is, main supply line diameter should not be less than the branches, it will ultimately become a dead end.
For piping works, long angled elbows should be used instead of short angled elbows, which creates so much hindrance in the passage of flow.
Forwards pump should be 10-15% over capacity than the required flow. CIP return pump should be self-priming as well as the flow of the return pump should be greater than the forward pump to avoid accumulation.
Steps of CIP
Milk constitutes sugars, fats and minerals. Steps of CIP is basically to clean these major constituents one by one in an efficient way.
Water at the start of the CIP just after finishing milk/product transfer. Purpose of water flush to dissolve sugar and flush down. Otherwise, this lactose or sugar burned out if in contact with caustic or acid.
Caustic/Base solution react with fat particles and saponification occurs. Fat particles are considered to be the hardest constituent to clean as compare of other two.
Between caustic and acid, water circulation is to maintain pH throughout the line and reduce the risk of reaction between these two.
Purpose of acid circulation step to wash out deposited milk contained minerals.
The purpose is to flush out the acid residues.
Final flush continues till pH of the line is attained. WHO recommends the pH of drinking water must be in between 6.5 to 8.5. The attained pH among these two figures would be fine.