Conductivity Measurements for Clean-in-Place (CIP) System

Background

In the food & beverage, pharmaceutical, and chemical industries, tanks and piping are cleaned and sterilized with various cleaning solutions, fresh or hot water, or steam after manufacturing products is completed. Clean-in-place (CIP) is the system designed for automatic cleaning and disinfecting in these processes. Recovery of cleaning solutions contributes significantly to the reduction of chemical and/or wastewater processing costs.

Process Overview

Common CIP processes first wash the tanks and piping with cleaning agents such as sodium hypochlorite, caustic soda, or nitric acid. Then the detergent is washed with freshwater; the detergent is collected at this time. When the detergent concentration of the washing solution reaches the reference value or less, the collection is stopped and the solution is released to the drain line.

Cleaning is carried out under certain conditions, in a precise order, and utilizes multiple detergents. If the wrong operation is performed, it cannot be detected externally; therefore, it is impossible to perform the specified washing and reduction losses which may occur due to operational errors.

Challenges

The number of cleaning agents required could present a manufacturing cost challenge. The recovery of cleaning solutions significantly reduces chemical costs as well as wastewater processing costs. Therefore, accurate and reliable conductivity measurements are critical for clean-in-place (CIP) or water-for-injection (WFI) applications; inaccurate readings can cause runtime losses and an increase in material and energy usage.

Solutions

Yokogawa’s FLEXA series analyzers can connect to either inductive or contacting conductivity sensors. Each type of sensor technology serves a specific purpose. An inductive conductivity sensor offers a wide measurement range and is well suited to use in dirty, corrosive, or highly conductive solutions. In those applications, it requires less maintenance than a contacting sensor. Contacting conductivity sensors are ideal for use in pure and ultrapure water applications. Their high sensitivity to ions present provides the highest accuracy for low conductivity measurements.

Yokogawa’s ISC40 inductive conductivity sensors have earned a favorable reputation in the recovery of cleaning solutions. Accurate conductivity measurement in CIP systems can reduce operating costs by up to 10%. 

Benefits

Washing detergent with freshwater is time-sensitive. Introducing a conductivity meter makes it possible to prevent unnecessary cleaning. Since cleaning agents have high conductivity while freshwater (distilled water) has low conductivity, a conductivity measurement allows the operator to distinguish which liquid is flowing through the process piping. This enables optimization of the cleaning and sterilizing process, resulting in: 

• Reduced operating costs
• Improved precision in boundary surface measurement

Product Recommendations

Conductivity Measurement System: 
Process Liquid Analyzer:
2-wire FLXA202 Conductivity Analyzer
4-wire FLXA402 Conductivity Analyzer

 

Chemical Solution (High Concentration) Conductivity Sensor Selection:
Inductive Conductivity Sensor Selection: 
With the inductive conductivity, ISC40 series, one sensor can measure the full range of conductivity from 0-2000 mS/Cm. Steam sterilization capability is possible since the measurements can be performed at process solution temperatures of -10 to 130°C and pressures no greater than 2 MPa (20 kgf/cm2).

Option #1: 
ISC40G General Purpose Sensor
ISC40S Intrinsically Safe Sensor
Available in PEEK and PFA material for more aggressive chemicals

Holder Selection:
ISC40FS/ISC40FF Insertion of Flow-thru assembly
PR10 Retractable assembly

Freshwater (Distilled water) Sensor Selection:
Contacting Conductivity Sensor Selection: 
Analog and Digital SMART sensors are available. Analog options allow users to interface with a traditional system. SENCOM technology allows sensors to transmit and receive data when connected to a transmitter/analyzer or any PC. A SMART digital sensor maintains specific measurement and calibration data on an integrated chip that is integral to the sensor. This provides easy plug and play solutions. The data management software optimizes the performance of sensors for enhanced reliability and process safety.

Option #2: 
SC4A Conductivity Sensor (fittings available for insertion, sanitary, or retractable installations.)