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    CO₂ sourced in-house gives independence

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    CO₂ recovery in breweries is part of Steinecker’s sustainability concept.
    • This is where the CO₂ separated from the fermentation process is collected.

    In summer 2022, many people learned the hard way just how crucial CO2 is to the brewery. All over the world, the sector suffered from shortages and high prices, and some smaller breweries had to stop production at times. And yet, the problem could have been avoided, at least partially, because the brewing process (fermentation, to be precise) actually generates quite a lot of CO2 – even more than the brewing and filling processes need. In order to tap just that potential, Steinecker offers proprietary CO2 recovery systems.

    To date, CO2 recovery has been used almost exclusively by breweries with a large beer output, though there are definite differences, depending on the country and infrastructure concerned. Relatively small operations mostly outsource the gas, which is a by-product of fertiliser and ethanol manufacture. But supply chains had already been disrupted during the Covid-19 pandemic. And in response to soaring prices for energy, especially natural gas, in 2022, fertiliser producers in many regions cut back their energy-intensive manufacturing operations. That resulted in severe supply bottlenecks, which were further exacerbated by periods of hot weather and warmer summers as CO2 is also used as a coolant and the basic ingredient for dry ice. Moreover, because hot summer days tend to make people reach for a refreshing drink, the beverage industry, too, needed larger amounts of CO2. Against this background, more and more companies are considering the option of recovering the CO2 generated in the fermentation tank. “In the past, producers might consider using CO2 recovery for outputs of several hundred thousand hectolitres or more,” says Peter Gattermeyer, Head of Technology & Engineering at Steinecker. “In view of today’s prices and the resulting supply-chain independence, it definitely makes sense to check out the options for CO2 recovery from an annual production of about one hundred thousand hectolitres upwards.”

    Steinecker has offered CO2 recovery systems since 2005, with more than 250 already up and running worldwide. The biggest of them planned so far, for an hourly throughput of four tons of raw gas, is currently being built in Spain. The recovery equipment installed at Ustersbacher in Bavaria saves the brewery up to 800 tons of CO2 per year. These systems are part of Steinecker’s sustainability portfolio, says Peter Gattermeyer: “Our Brewnomic concept consists of three pillars: energy, water, and re-usable materials and substances. The latter include not only spent grains and yeast but also the CO2 generated during fermentation.” The brewing specialists at Steinecker make sure their recovery solutions are tailored to a brewery’s individual needs, he emphasises: “We don’t sell stand-alone solutions. Instead, our systems are fully integrated into the brewery’s production process and energy concept.”

    In view of today’s prices and the resulting supply-chain independence, it definitely makes sense to check out the options for CO₂ recovery from an annual production of about one hundred thousand hectolitres upwards. Erwin HächlPeter GattermeyerHead of Technology & Engineering at Steinecker

    The oxygen displacer

    What exactly is CO2 needed for in a brewery? The smallest part, a mere four to six grams per litre, is used for the beer itself. Without it, a beer won’t taste good, nor would it have bubbles or a head. But quite a bit more CO2 is required to render the beer shelf-stable. To ensure a lengthy shelf life, the beer must not absorb any oxygen in the process steps after fermentation. CO2 is ideally suited for removing oxygen from tanks, pipes, valves and bottles before the beer flows in. And the water used for clearing the pipes in the cold section or for pre-rinsing the filler must not contain any oxygen, either, and is therefore purified with CO2. Many breweries need further amounts of CO2 for making carbonated beverages like mineral water or fizzy drinks.

    But breweries not only consume CO2, they also generate quite an impressive amount of it in the fermentation tank where yeasts turn malt sugar into alcohol: roughly up to five kilograms of CO2 per hectolitre of beer.

    Recovery concept – the details

    The starting point for CO2 recovery is the fermentation tank’s exhaust air. The recovery process begins when fermentation is in full swing and the exhaust air contains at least 95 per cent CO2:

    • First, the CO2 collects in the buffer balloon.
    • Before the raw CO2 gas is compressed, a rain of water washes out any unwanted constituents like sugar or beer residues.
    • For the next stage, Steinecker offers an additional aerosol separator as an optional extra, to make sure that all liquid residue is removed. That prevents deposits forming in the compressors, reduces wear and tear and substantially upgrades the compressors’ efficiency.
    • The following step requires meticulous care: Activated carbons are used to remove any remaining aroma compounds from the CO2. That is because, depending on the type of beer (e.g. top-fermented) and the brewing process used (like high-gravity), various fermentation by-products are formed, including pungent-smelling, sulphurous substances. If the CO2 recovered is intended for mineral water or dealcoholised beer, for example, it is absolutely essential that such unwanted aroma compounds be reliably and completely removed. That is why, in addition to its activated carbon filters, Steinecker also offers an optional filter for removing hydrogen sulphide. The system is specifically designed to meet all of the brewery’s needs, so as to make sure the quality of the CO2 recovered is perfectly suited for the intended application.
    • The CO2 is dried and once again purified, and then stripped of all the remaining oxygen by means of the countercurrent gas flow method. The 99.998 per cent pure CO2 thus produced is cooled down to an extremely low temperature in a refrigeration system specifically designed for this purpose in order to liquefy it, after which it is stored in a well insulated accumulator tank.
    • An evaporator warms up the CO2 to return it to gaseous state, so it can be passed into the piping leading to the consumers in the brewery.
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    Integrating a Steinecker CO₂ recovery system in a brewery’s operations

    Whatever the quality of the raw gas, our filters will remove all unwanted aroma compounds from the recovered CO₂, to make sure it can be used for any application, even for highly taste-sensitive products like mineral water. Erwin HächlPeter GattermeyerHead of Technology & Engineering at Steinecker

    Highly flexible in all respects

    Quite a lot of energy is needed for the CO2 recovery process, mainly for liquefaction and evaporation. To this end, Steinecker examines the energy concept of the entire brewery, says Peter Gattermeyer: “A brewery has many sources of thermal or cooling energy. So you no longer need any primary energy from the heat supply system in order to evaporate the CO2. We take a close look to find out how the CO2 recovery system best fits into the production process and into the energy circuit, and dimension its capacities for a perfect match.” The coolant needed in a brewery’s various cooling processes, such as glycol, is run in a closed loop. It absorbs a sufficient amount of thermal energy at the beer production’s chillers in order to return the CO2 to gaseous state. And conversely, as heat is released during CO2 evaporation, the glycol’s temperature is reduced so much that it can again be used as a coolant, hence easing the load on the brewery’s main refrigeration system. This exchange of thermal and cooling energy not only provides savings in primary thermal energy, it also significantly helps cut power consumption for refrigeration. On request, Steinecker can also produce a refrigeration system for CO2 liquefaction that uses the eco-friendly coolant CO2.

    Flexibility is a key priority not only in Steinecker’s specification of cooling and heating capacities to make sure these are perfectly tailored to a company’s overall energy concept. The CO2 recovery system itself is not a one-piece entity, either, but consists of individual units that can be installed in a flexible configuration. That makes is relatively easy to fit it into the space available in each case. Flexibility is also provided in terms of the methods offered for treating the CO2 recovered, as Peter Gattermeyer explains: “Whatever the quality of the raw gas, we offer suitable filter concepts for any possible application, right through to use for highly taste-sensitive products like mineral water.”

    Self-sufficiency is no vision, it can be done

    Can CO2 recovery render a brewery completely self-sufficient? “If it makes only beer, yes,” says Peter Gattermeyer. “Roughly 2.5 kilograms of CO2 can currently be recovered per hectolitre of beer. Of that, 500 grams are bound in the beer itself, and the rest is enough to supply all of the brewing and filling processes. In most cases, CO2 sourced in-house will be insufficient only if the brewery also produces further carbonated beverages.” So that offers plenty of development potential if the ambitious sustainability targets set for Steinecker’s product portfolio are to be reached in this field as well.

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