7 More Tips to Improve the Cleaning In Place (CIP) of your Falling Film Evaporator

Some time ago, Jan de Geest came up with “7 Tips to Improve the Cleaning In Place (CIP) of your Falling Film Evaporator” without knowing the details of your evaporator system. When visiting customers and different production facilities, we find that CIP is often one of the more focused items of discussion. With that being said, I would like to share 7 more general tips for CIP that I have recently discussed with some of our customers:

Tip 1 – Are the Pumps Suitable for both Production and CIP?

Pumps in an evaporator system should be selected for both production and CIP cycles. As logical as this sounds, you would be surprised how often this is not considered. During CIP, the flow is generally much higher than during production. In addition, pumps are expected to discharge more pressure as they need to compensate for the pressure drops through the spray balls. Pumps that are selected for just production purposes and not CIP can sometimes neglect these scenarios and can result in inadequate cleaning of the niche areas that the spray balls target (i.e., evaporator heads, vapor ducts, separators, etc.). This will result in residual fouling, scaling, and possible bacteriological issues if not mediated in due time. Often the customer will run two CIP cycles rather than fix the issue at hand. Any additional CIP washes are lost production time.

Tip 2 – Are the Spray balls suitable for the application?

Spray balls are a great way of cleaning tedious spots where normal CIP flow cannot reach. However, if the spray balls are not properly sized or selected, they are as good as forgotten in evaporator cleaning. When selecting a spray ball, it is always important to think of the placement of the spray ball and its spray projection when activated to ensure that all targeted areas can be reached with the spray pattern. In certain applications, you will need overlapping sprays to get the coverage you need and avoid blind spots and shadowing.

In addition to the spray balls being suitable for the application, it is just as important to verify that the spray balls are cleaning their targeted areas. Visual inspections should be implemented to ensure that they are still connected, as sometimes they can come off. Disassemble to verify that the spray balls are free of any debris that can affect the spray pattern.

Tip 3 – Having Different CIP Recipes

As facilities diversify the range of products, they produce they should consider different cleaning strategies. Each of these products have a different chemistry, and one way of cleaning is not always the best for the other products. For instance, in the dairy industry, some products leave more protein fouling (such as Whey Protein Concentrate, “WPC”), whereas others leave more calcium fouling (such as permeate). Typically, with more calcium fouling products, you would emphasize the acid wash, meaning dedicate more time in the CIP wash to acid cleaning. However, with more protein fouling products, you would emphasize the caustic wash, meaning dedicate more time in the CIP wash to caustic cleaning. With cleaning an evaporator, it is critical to understand the chemistry of the product and the nature of the fouling so that the CIP of your system can be as effective as possible. 

Tip 4 – Reclaim Chemical Reuse Frequency

Reclaimed chemical washes are typically used as the pre-wash for most evaporator CIP sequences. This is intended to get most of the crud and buildup in the system out before the main chemical washes are initiated. If you are intending on using reclaimed chemicals for your main washes, you may struggle to remove the soils from the equipment. Typically, conductivity is used to verify the strength of the chemical wash solutions. However, once the wash has been through the evaporator and dissolves soils, those chemicals have reacted with the soils and formed mineral salts. This can lead to false conductivity readings in which the conductivity is reading the salts in the solution and not the strength of active chemicals in solution. If you plan on using reclaimed chemicals for your main washes, you will have to verify the strength of the solution by pH measurement. 

Tip 5 – Target Wash Times 

Cleaning is essential in the maintenance of an evaporator system, and although getting the system ready for more production is of the essence, thorough cleaning should be prioritized before this. It is recommended that a minimum of 2 complete cycles per chemical wash be completed during each CIP (acid, caustic, etc.). It is difficult to generalize a period of time for each wash, as each evaporator system is different in terms of cleanliness, but as a rule of thumb, a minimum of 60 minutes should be used for each chemical being used. Please note that this time does not consider the flush out times of the system.

Tip 6 – Conductivity Element on Discharge  

Most CIP systems are automated to some degree, and some evaporators have more automation and analytical elements than others. One very valuable element that you should consider for your system is a conductivity element on the discharge line of your system. Some systems don’t have issues with their cleaning times, as touched upon on Tip 5, but instead, find themselves having long CIP sequences due to the flush out times. One very good way to cut down on flush-out times is by installing a conductivity element in the system discharge line. As the system flushes out, the conductivity will indicate whether most of the chemicals are out of the system so that the system can start the next rinse. This, in the long run, is a small investment when looking at all the time that the facility can save on CIP, making more time for production. 

Tip 7 – Sequencing “Dead” Time 

Depending on how the CIP sequence is programmed, there is usually a sequence where all the spray balls in the evaporator system are activated for targeted cleaning areas. Some facilities activate these spray sequences several times with an intermittent period where the system must discharge the added volume from the spray balls in the system. It is important to ensure that the “dead” time in between these spraying sequences is sufficient enough to allow the system to discharge the extra volume added in and prevent level buildup.

Aaron Amorim
Evaporator Woes - Vacuum Control, Velocity, and Carryover
GLM Luebbers

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