Process Engineering

CIP – SIP - Systems

The CIP - process (Cleaning in Place) comprises a range of mechanical and chemical processes, mainly used in the pharmaceutical, cosmetic and food industries. During CIP cleaning, vessels, pipelines and valves are cleaned between the individual production runs on the product-contacted surfaces, without these having to be dismantled beforehand. Practical experience and experiments have shown that the mechanical cleaning effect of mechanical cleaning solutions is influenced by the flow rate and turbulence of the cleaning liquid. The temperature and concentration of the cleaning solution are other factors which influence the cleaning speed and must be considered when designing a cleaning system. The CIP process plays a key role in ensuring product safety and hygiene, minimizing downtime while maximizing plant efficiency. Particular attention is paid here to the rising costs for water, energy and an optimized consumption of chemicals, which must be adapted to the individual products to be cleaned. For the development of cleaning processes, it is important to know the properties of excipients and active substances, in order to make a suitable choice of cleaning agents. Sometimes the false selection of detergent can significantly extend the cleaning time or prevent a complete cleaning. The degree of cleaning is dependent on many factors- Besides the type of contamination, the properties of the product-contacted surfaces, their installations, corners, edges, sealing configurations, low-flow/stagnant zones,  e.g. in T - pieces, puddles and domes, as well as their operation conditions, play a decisive role.

The effectiveness of a cleaning is dependent on

  • Design features of the plant area to be cleaned (GMP - Good Manufacturing Practice)
  • Suitable material selection and material properties
  • Suitable cleaning agent
  • Proper cleaning conditions

The important characteristics of CIP cleaning

  • Flow rate in pipelines and valves (depending on the cross-section of the pipelines, between 1 - 4 m/sec)
  • Duration of rinsing
  • Spray pressure on the cleaning heads
  • Temperature of the cleaning solution
  • Cleaning agent –alkaline-based cleanser with additives, for better retention of the dirt particles (avoid using foaming cleansers if possible)
  • Cleaning agent – acidic rinses (for adhesive substances, e.g. lime scale deposits after alkaline cleaning)
  • Disinfectant (SIP or chemical)
  • Reaction time of the cleaning agent and the temperature
  • Size of the plant
  • Reproducible process due to fully automated sequence
  • Documentation of the cleaning process

Purpose of CIP/SIP cleaning

  • Complete removal of product residues
  • Biofilm removal
  • No cleaning agent residues
  • Sterility of the plant components and pipelines

Sequence of a CIP cleaning, e.g. in the pharmaceutical industry

  • Pressure test (check tightness of the plant)
  • Evacuation of the plant for melting-off process (e.g. in the case of fat-containing products)
    • Melting-off with ultra-pure steam
    • Concentrated ablation of molten product residues
  • Pre-rinse hot, in order to remove coarse soiling
  • Clean with an alkaline agent (poss. with additives for better retention of dirt particles)
  • Rinse hot during emptying procedure (rinse out alkaline cleaner and product residues at the same time)
  • Rinse with purified water during emptying procedure (ultrapure water)
  • Clean with an acidic solution to remove lime scale deposits and leaching stone.
  • Rinse with purifed water
  • SIP (Sterilization in Place) Evacuate plant area. After this regulate the steam pressure up to the overpressure range. Then drain the condensate.
  • Dry the plant via vacuum e.g. with hot sterile air supply
  • The sequence of cleaning and step times is modifiable.
  • The detergent concentration of the cleaning agent is variable.
  • The cleaning agent concentration can be combined in a fresh batch to an optimally effective cleaning solution (stack cleaning).

Sterilization in Place (SIP)

Sterilization in Place is a site-based sterilization via ultrapure steam of process plants which do not require disassembly. Any components which come into contact with the product are thereby sterilised. As a general rule, the SIP process is carried out with saturated ultrapure steam of at least 1 – 3 bar. In order to reach a sterilization temperature of 121 °C, ultrapure steam with a pressure of <1 bar is required. Depending on requirements, the temperature is controlled and documented, depending on the steam pressure of the reaction time. The plant parts to be sterilized should be evacuated before the steam sterilization, in order to avoid air pockets and to achieve a fast and even temperature distribution.

CIP systems integrated in process plants

All internal surfaces of the process plant are primarily cleaned by a Cleaning-In-Place process. The homogeniser serves as the conveyor unit for the CIP solution.

Other equipment parts of a process plant include, for example:

  1. Suction hose for liquids
  2. Suck-in lance for powder
  3. Phase vessel

The mixing plant should be designed in such a way that a maximum quantity of the product in the target vessel can be transferred. Hereby, the target vessel can also be understood as the inflow of a filling machine. The objective of this design is to minimise the amount of residual product, in order to ensure that only a minimum of residual product is introduced into the waste water. The bottom of the vessel, the wall scrapers, the existing surfaces, the length and the gradient of the discharge pipe behind the homogeniser should be so designed that (if possible) no residue quantities remain. All pipelines within the process plant are to be integrated into the CIP process. All additional pieces of equipment to ensure the Cleaning-In-Place process are to be designed in such a way that these do not constitute a source of physical, chemical or microbiological contamination. Air bridges are provided, especially in front of waste water connections, in order to prevent microbial re-contamination.

Cleaning process in plants

The Cleaning-In-Place process generally consists of the following steps:

  1. Rinsing of the plant parts and the pipelines with hot water in flow-through procedure. The purpose of this step is to remove product residues directly into the waste water without contaminating the equipment that was actually intended for the CIP.
  2. Clean with a solution of alkaline cleaning agent at approx. 70°C Circulation of cleaning fluid with chemical cleaners. The purpose of this step is to remove all visible product residues. Rinse during the emptying of the vessel.
  3. Cleaning with a cleaning solution (acid) Removing lime scale deposits by circulating cleaning liquids with chemical cleaners. Circulating hot water until the temperature of equipment parts reaches 80°C to 90° over a certain period of time. The purpose of this step is thermal disinfection of the surfaces and dissolution of lime scale deposits. Rinse during the emptying of the vessel.
  4. Rinse with cold de-ionized water in a circulation procedure over the rotor jets. Rinse during the emptying of the vessel.

These steps can be successive, repeated, carried out with or without additional cleaning agents or even skipped. Optional equipment of the CIP system:

The cleaning quality can be monitored by means of a conductivity sensor (final rinsing water < 50 µS/cm at 20 °C).

SEEFRIED Verfahrenstechnik GmbH can assist you in the interpretation, the CIP procedures and procurement of CIP and SIP systems and the related process equipment.