Filtration is the last step in the brewing process in which a beer’s quality can be actively influenced. It ensures a brilliant, clear product and high microbiological stability. More than 90 percent of breweries rely on precoat filtration using kieselguhr (also known as diatomite or diatomaceous earth) as the filter aid. While kieselguhr offers many advantages, it also has its disadvantages, particularly with respect to disposal. It’s those disadvantages that prompted Krones to look for alternatives. And now we’ve added two clarification technologies to our portfolio: After five years under development, the Phoebus membrane filtration system has been available for sale since early 2020. In the same period, Krones has also been working on a precoat filtration system that uses an alternative filter aid. That system, too, is now ready for market.
At the heart of this process lies a compressible filter aid developed by Krones and now sold by KIC Krones under the name celcare.
The Krones celcare series comprises two products: For the initial precoating, 100 percent cellulose fibers are used. Then, in the second precoating and in the body feed, a combination of cellulose and perlite is used. Both materials are combined in various amounts and at various degrees of fineness.
In order to achieve the desired degree of separation (and, ultimately, clarity or brightness), the filter cake has to be compressed in a controlled manner. And the process technology experts at Krones’ Steinecker plant have developed a way to accomplish that: A bypass is used to maintain the necessary differential pressure by circulating filtrate back into the unfiltrate feed (see graphic). During filtration, the dosage of celcare can be reduced considerably once the initial “precoating” stage (of rapidly building up the filter cake) is complete. In practical terms, that means the longer the filter has been in use, the less filter aid needs to be added.
A sustainable alternative filter aid
But Krones celcare doesn’t only meet economic needs. It also performs well in terms of both sustainability and quality. Cellulose is a natural, renewable raw material that can simply be disposed of by the usual means after use. In addition, studies are currently underway to examine whether it can later be used in biogas plants.
The beer quality achieved by precoat filtration using Krones celcare matches that achieved using kieselguhr.
Generally speaking, all breweries that currently use Steinecker TFS filters can be retrofitted to work with celcare. Third-party candle filters can also be converted to TFS technology. The experts from the House of Krones collaborate closely on the implementation. The Steinecker plant’s process technology specialists make the necessary adjustments to the controls and the filter. In the case of the filter, that means simply adding an inductive flow meter and a control valve to the filtrate line that feeds to the bright-beer tanks, to ensure a constant flow of filtrate independent of the output of the pump used to regulate differential pressure. Breweries can purchase Krones celcare filter aid from our consumables specialist, KIC Krones, whose experienced team is available to answer any and all questions brewers may have on all aspects of keeping Krones machines and lines well supplied.
|Beer filtration using Krones celcare|
|Filtration principle||Precoat filtration using a compressible filter cake based on the filter aid Krones celcare|
|Filter aid||– Cellulose fibers for the initial precoat,
– combination of cellulose fibers and perlite for the second precoat and body feed
|Flexibility to respond to the
|Continuous adjustment of the dosage of Krones celcare in the body feed to enable flexible response to the quality of the unfiltrate|
|Filtration cycle||12 to 14 hours|
|Disposal of filter aid||– Fertilizer
– Potential use in biogas plants (currently under testing)
consumption; operating costs
|Comparable to kieselguhr|
P = Pressure
F = Flow
Q = Turbidity (Quality)
Bypass for recirculation