Krones: Recovering residual materials from the brewing process

For most breweries, waste material from the brewing process is now more of a troublesome disposal issue even though it has in fact been possible to recycle this biomass for some time now. It also makes perfect sense to do so, as its use for energy recovery in a biogas plant, in particular, can significantly reduce a brewery’s reliance on fossil fuels. But the brewery would then have to invest in a biogas plant and a combined heat and power system or a boiler system, which in the past was not a lucrative proposition given the very low energy costs in the world. .

Growing price pressure makes efficient production all the more important

In 2017, Steinecker developed the Brewnomic modular kit system aimed at helping breweries become energy self-sufficient and carbon neutral. This reduces the amount of thermal energy and electricity required in the brewing process enough to make a brewery self-sufficient through the recovery of its waste materials. But even in 2017, it was clear that any investment in this form of energy supply would take a very long time to pay for itself.

The low recyclability of residual materials (especially spent grains) required a long residence time for the biomass in the methanation reactor. 25 to 30 days of fermentation were necessary to obtain a sufficiently high methane yield, which had a direct effect on the size of the plant and therefore on the costs incurred. In addition, the Circular Economy Action Plan adopted by the EU in 2020 stipulated that nutrient-rich waste materials should no longer be used solely for energy production. Thus, in the medium term, the biogas plant + cogeneration system would no longer be eligible for approval because the residual materials from the brewing process contain a lot of nutrient-rich substances such as carbohydrates or proteins.

So a new way to achieve this had to be found, and Steinecker managed to come up with exactly the right solution: the Phoenix BMC Biomass Conversion System.

Recover residual materials from the brewing process with Phoenix BMC

It is not only the low recyclability of residual materials that is responsible for the long fermentation time, but also the presence of inhibitors. To solve this problem, these substances (proteins and ammonium) must be separated from the biomass before the production of methane. In this process, a protein hydrolyzate and a mineral fertilizer are obtained from the brewing residues, thus respecting the stipulations of the action plan for the circular economy of the EU while also making possible biogas installations much more small, that is to say more affordable, since the fermentation time of a biomass without inhibitors is only a few days.

And plant proteins, in particular, are more sought after today than ever. The current trend of many people to adopt a sustainable, healthy and vegan lifestyle has had a significant effect on the demand for plant-based protein sources. These protein derivatives are necessary not only to produce milk substitutes such as vegetable drinks or vegan foods, but also to manufacture food supplements.

Mineral fertilizers are also highly coveted in the market and are another new source of income for the brewery.

Phoenix BMC consists of three modules:

Module 1

  • Mash tanks for the dispersion and hydrolysis of solid mash residues

  • Membrane filter to separate protein hydrolyzate

Unit 2

  • Fermenter for the souring process

  • Membrane filter to separate remaining solids

  • Ion exchanger and mixing tank for obtaining mineral fertilizers

Unit 3

  • Biogas plant for obtaining methane

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