A lot of these challenges center on the clean-in-place (CIP) operation, since inefficiency in this operation can represent a significant source of extra costs.
CIP, used by virtually every dairy operation, is the procedure for cleaning and sterilizing food processing equipment, Kyle Knutson, product manager, North America, at Emerson Automation Solutions told DairyReporter.
The process is conducted by circulating water and chemicals through sections (called circuits) of the plant.
This removes any product deposits and ensures the process equipment and pipework are clean/sterile and ready for the next process to be run. Typically, dairy plants run the CIP program at least once per day, or more, depending on the process and application.
Knutson said CIP programs differ from application to application but traditionally they consist of three basic steps.
The first is flushing. Dairies typically start their CIP process by running warm water through the pipes for a pre-determined amount of time.
Following this, an alkaline detergent and/or acids are circulated at a temperature between 140-167oF, and third, hot water is circulated to disinfect the piping and rinse out any remaining chemicals.
These steps present measurement challenges that can induce energy loss and create waste, which ultimately leads to a higher cost of operation, Knutson said.
He noted all dairies share seven CIP challenges.
1. Product left in pipes
During the CIP process, Knutson said, any product left over in the circuit will be unusable as soon as it encounters the caustic chemicals used for cleaning.
Pigging, a common practice used to clean pipes, is often not able to be performed, as intrusive measurement sensors, which penetrate a pipe, would be damaged.
Utilizing a non-intrusive temperature measurement allows a plant to avoid the need for thermowells or process penetrations that would impede the use of pigging, harvesting additional product before the CIP program begins, resulting in less product waste.
Using an advanced surface temperature solution that applies a thermal conductivity algorithm to measured ambient and pipe surface temperatures can provide an accurate and repeatable internal process measurement.
2. Chemical holding tanks
Large tanks are used to hold chemicals utilized in the CIP process. Making sure that these chemicals are used efficiently and not wasted is vital to reducing costs and ultimately saving money.
A hygienic pressure transmitter with high accuracy at low-pressure ranges allows for repeatable and accurate readings. This ensures reliable hydrostatic level measurements at all times, while hygienic fork switches allow for reliable level alarms. Adjustable switching delay prevents false switching in turbulent applications.
3. CIP processes running too long
Some of the most critical CIP measurements are return temperature and conductivity, Knutson said.
Accurate temperature measurements with drift alert and hot backup ensures temperature stays online and limits the need for additional CIP runs. Conductivity is also important to identify fluid changeover within a CIP process.
A four-electrode conductivity sensor intended for measuring in the pharmaceutical and food and beverage industries can be utilized to accurately measure conductivity.
The broad dynamic range of the sensor (1 - 1,400,000 μS/cm) makes it ideal for CIP applications. It also allows for quick responses to the needed temperature changes.
In addition, an advanced surface temperature solution produces accurate process temperature data without the need for pipe penetration. Surface temperature measurements can also help monitor temperatures in hard to measure places, ensuring that CIP processes are not running longer than necessary. This, in turn, limits waste of chemicals and utility heat.
4. Detection of milk and water phases
During the CIP program, it is important to be able to detect different phases in the process. This allows the plant to differentiate between milk, water, and caustic chemicals, according to Knutson.
When plant operators have access to this information, they can fully utilize the product and ensure as little as possible goes to waste. Knowing what phase the process is in also allows for quicker changeover from CIP back to product production.
Utilizing density measurement phase detection, such as with a Coriolis meter, allows for dairies to identify different densities of the product, effectively making plant operators able to detect the difference between the product, water rinse, and caustic cleaning solution.
5. Maintaining turbulence for cleanliness
Knutson said the CIP process requires that the liquid moving through the pipes maintains a certain velocity for optimal cleanliness. Liquid moving too slow can leave behind undesirable chemicals and spoiled product.
Utilizing accurate velocity measurement allows for plants to maintain the highest degree of sanitation. A Coriolis transmitter should be utilized to provide the most accurate measurement of velocity. It can calculate derived variables such as volume flow rate, flow totals, and concentration measurement which can then be translated into an output signal useful for process control.
6. Steam trap failure
During the CIP program, condensed steam, known as condensate, is collected in steam traps and a condensate tank before being pumped back to the boiler. If the steam trap is failing, steam can be lost and require more energy to keep the plant running. Effectively monitoring the health of the steam traps ensures energy is not being wasted, thus decreasing energy costs as well as maintenance hours.
The solution comes in the form of a wireless acoustic transmitter that allows visibility into steam traps and pressure relief valves by accurately communicating acoustic level and temperature data. The steam trap monitoring software provides real-time, continuous information about steam trap conditions, energy usage, and emissions.
7. Utility steam heating
Dairy processing uses more energy than any other sector of food processing, and Knutson said CIP, especially, accounts for a major portion of this energy use. In dairy plants, steam is used extensively for sanitation and cleaning during the CIP program. Inaccurately measuring steam while using it to clean equipment can be costly for plant operators.
Multivariable differential pressure (DP) transmitters can accurately measure the flow of steam, ensuring it is used efficiently and effectively. Ultimately, this leads to a great energy cost reduction.
Just knowing these seven challenges exist and that solutions are straightforward with the correct instrumentation can save dairy processors time and money in energy and wasted product, as well as help maintain efficient plant operations.
Emerson offers hygienic instrumentation and measurement solutions to help dairy processors address these issues and improve the quality of their products.