7 Tips to Improve the Cleaning In Place (CIP) of your Falling Film Evaporator
GLM Hydro Falling Film Evaporator Tips: –The majority of Falling Film Evaporators have a Cleaning In Place (CIP) system. Most of them are automated. Some evaporators have a higher level of automation than others, especially those that run a CIP every day, like falling film dairy evaporators. In the dairy industry, not only fouling plays an important role, bacteriological growth or bacteria activation are factors as well. Without knowing the details of your Falling Film Evaporator or the product you run, I can give you 7 general tips for improvement:
Tip 1 – Keep Internal Mixing Low
When coming off production, run the product levels as low as possible. When you bring in water or condensate for flushing you want to keep the internal mixing as low as possible. High levels can lead to long flush out times. Be as effective and efficient as you can. When the process allows, it sometimes may be better to drain all product levels!
Tip 2 – Ideal Temperature
When you bring in your cleaning solution, make sure that you bring the temperature to an ideal level in which the cleaning liquid is most effective. Be cautious not to use a cleaning agent or temperature level that your materials of construction cannot handle. I have seen evaporators being eaten away by using the wrong cleaning chemicals at the wrong temperature, be careful with that.
Tip 3 – Concentration of the Cleaning Solution
What goes for the temperature, goes for concentration of the cleaning solution! Make sure that you do not dump in all the cleaning chemicals at once. Especially when the concentrated liquid is pumped into the feed of the system. You should dose in the cleaning liquid in such a way, that the strength is matching the optimum. Avoid creating a plug flow of highly concentrated cleaning solution, this can have a negative effect on dissolving the fouling. It can also cause damage to materials and gaskets when you have a high plug flow of CIP pumping through the system.
Tip 4 – Consider a Prewash
Once the CIP solution is in the system very often the evaporator is brought into a circulation mode. Make sure that there is not too much fouling at the first quarter of the CIP run. This fouling, now on the loose in your system, will spray dirty CIP agent on the internal walls of the evaporator. And don’t forget: acid loses its’ activity when calcium fouling is the problem. In some applications it may be more effective and efficient to do a prewash to get the first heavy fouling removed.
Tip 5 – Avoid Build-Up at the Final Passes
If you have your evaporation reduced (reduce the delta T’s needed for evaporation) the liquid loads on the final passes or effects get higher. Make sure that the pumps are able to pump a higher CIP load, for example using a frequency drive on the final motors, so you can speed them up for CIP. Avoid level build-up.
Tip 6 – Run High Flows
Run the flows as high as you can without flooding the system. You want to avoid high levels in the evaporator sumps that create a long flush out time. If you have a long train of multiple effects, with a high concentration factor, it may be worthwhile to split the system into two segments, for example pre-heaters and evaporator on a separate boil out.
Tip 7 – Keep an eye on your Spray Nozzles
Make sure that all the spray nozzles are working properly. Do not start spraying before the cleaning liquid has reached the desired concentration.
Bonus Tip – Know what is fouling your system
On top of all this it is important to explore what the fouling substance actually is, so you can choose the proper cleaning cycle and cleaning liquids. I advise to physically check the falling film evaporator before cleaning, that way you can literally see where the problem areas actually are before cleaning.
By running a CIP and do an inspection after the CIP you can see how effective the cleaning has been and if there are any modifications necessary. Another area to look into is why is there fouling to begin with. Is there anything you can do to avoid fouling or to make the runs longer? Time, temperatures and concentrations play an important role on running times. Especially in those applications where the system does not run under the original conditions. When you switched to a higher inlet concentration or you run on different product properties, modifications may be required to get optimal results.
I have seen large improvements on treating the product differently. For example: an PH correction of the product or operating on a different time/temperature profile can make the product less heat sensitive and will give you less bio fouling problems.
Contact us for more information when you would like to optimize your product, production process, equipment design and CIP solutions towards a better performance.
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