cleaning in place

Cleaning in place

The cleaning of complete items of plant or pipeline without dismantling or opening of the equipment, and with little or no manual involvement on the part of the operator.
Benefits of cleaning in place

Plant and equipment is cleaned to ensure we maintain product quality and process efficiency. Cleaning closed plant in place (CIP), if specified and managed correctly, gives certain benefits over manual cleaning; namely:

Reduced labour input (human intervention) to the cleaning and disinfection process.

Improved control over the cleaning parameters.

Recording of cleaning process.

Which can lead to:

Improved consistency of clean and therefore quality of product.

Improved documentation and therefore proof of clean.

A reduction in the cost of clean and time to clean

A reduction in the exposure to hazardous processes and chemicals

To successfully clean in place:

The process plant must be hygienically designed.

The CIP set or recirculation system must be designed to meet the requirement of the clean.

The process plant and cleaning system must be correctly operated, managed, maintained and audited.

The site must have an appropriate level of technical and engineering competence.

Cleaning energies

The principles of cleaning are always the same; whether it is manual cleaning of a utensil in a sink, or in a dishwasher or the CIP of a vessel. Energy in the form of chemical energy, thermal energy and physical energy are all required to remove the soil from the surface. As with all cleaning there needs to be a balance of energies to effectively clean a surface. For instance, if the physical energy input is reduced then this must be made up by either an increase in chemical or thermal energy or an increase in the time of contact with the cleaning solution.

With CIP the physical energy comes from the movement or impact of the fluid. In the case of pipework, the turbulence of the fluid flowing creates a physical shearing action on the internal wall of the pipe. With vessel cleaning the physical energy comes from the impact or flow of the cleaning fluid over the internal vessel surface.

Cleaning sequence

The typical cleaning sequence for closed plant (i.e. CIP) is the same as used for open plant cleaning.

A CIP cleaning sequence (cycle) involves the following steps. The variables (parameters) of the clean will depend on many factors including the process plant, the soil, the materials of construction and water hardness:

Prerinse - Gross removal of debris

Caustic Detergent Clean - Removal of attached soil utilising a detergent

Rinse - Rinsing to remove the detergent and soil residues.

Acidic Clean – removal of mineral scales, if required

Rinse - Rinsing to remove the acidic detergent.

Disinfection - Disinfection either by temperature or a chemical disinfectant

Final Rinse - Rinsing to remove chemical contaminates

Recovery CIP set

The schematic of a recovery CIP Set has two large recovery tanks; one is used to hold the detergent the other recovered final rinse water. There is also a clean water holding tank.

 

Typical cleaning cycle

 

Prerinse              Feed water to vessel from rinse recovery tank for 5 mins.
                              Return to drain.

Detergent          Feed detergent to vessel from detergent tank.
                              Return to detergent tank.
                              Allow to recirculate for 20 mins.
                              Recover detergent to detergent tank

Rinse                    Feed clean water to vessel for 5 mins.
                              Return to rinse recovery tank.

Disinfect             Feed clean water to vessel
                              Return to rinse recovery tank
                              While feeding water run disinfectant dosing pump for given volume.
                              Allow to recirculate for 5 mins.

Single use (total loss) CIP set

The schematic of a single use CIP Set shows the balance (buffer) tank, typically of the order of 200 litres and associated pumps, valves and pipework.

 

Typical cleaning cycle

 

Prerinse              Feed clean water to vessel for 5 mins.
                              Return to drain.

Detergent          Feed clean water to vessel
                              Return to balance tank.
                              When circuit made run caustic dosing pump for given volume and heat solution to required temperature.
                              Allow to recirculate for 20 mins.
                              Drain down vessel and balance tank.

Rinse                    Feed clean water to vessel for 5 mins.
                              Return to drain.

Disinfect             Feed clean water to vessel
                              Return to balance tank.
                              When circuit made run disinfectant dosing pump for given volume.
                              Allow to recirculate for 5 mins.

Drain                    Drain system and balance tank.