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Company

Tennents Brewery, Scotland

Application

CO2 recovery

Capacity

Recovers 4,200 tons of CO2 annualy, repurposing 95% into their brewery process

Pentair - How Pentair helps Tennent's Brewery to overcome CO2 volatility and reach CO2 self-sufficiency

BACKGROUND

Carbon dioxide (CO2) is an essential component in beer production, required for carbonating beverages, regulating pressure in tanks during fermentation and dispensing, purging oxygen from bottles and kegs during filling, and cleaning and sanitizing equipment. 

Like many breweries, Tennent’s Brewery, a Scottish-based brewery, relied on purchasing CO2, which can pose challenges, such as the environmental impact of transporting CO2 to the brewery and, depending on the CO2 merchant market, volatile market prices and supply risks.

Tennent’s required a fully end-to-end CO2 collection and recovery system, allowing them complete autonomy over recovering their CO2 and the capability to utilize it back into the beer production process. 

“As an environmentally conscious brewery, it was a natural decision to utilize the CO2 generated in our fermentation process and incorporate it back into our brewing. Thanks to Pentair’s expertise, we could implement the technology. From start to finish, our experience with Pentair was exceptional. They recommended a comprehensive system that allows us to recover our CO2 and reintroduce it back into our brewing process through a collection capability. With this system in place, we can avoid the fluctuations of the CO2 market and focus on consistent and reliable operations.”

- Alasdair Hamilton Engineering Manager, C&C Group Tennent’s Brewery 

THE SOLUTION

A common practice in brewing is to vent its CO2 into the atmosphere to release pressure within the fermentation vessels, which, in turn, increases the brewery's carbon footprint. 
As a brewery committed to sustainability, Tennent's sought to collect (or harvest) and recover the CO2 they previously vented. This was when they turned to Pentair for assistance.

Pentair, a process-oriented solution provider with a substantial worldwide footprint in carbon recovery solutions, supplied a complete package that included the collection, recovery, vaporization, and storage of CO2.

Harvesting CO2 from Fermentation

The first step for Tennent’s was to adapt its fermentation process from an open (atmospheric) fermentation to a closed fermentation vessel with controlled gas in and out. This change required a significant modification to the existing fermentation process.

Pentair used its Tank Top Valve technology to collect CO2 gas from Tennent’s cylindrical, conical fermentation tanks (CCT). This innovative design prepares the gas for harvesting and allows simultaneous cleaning of the fermentation tank from the same supply pipe, meaning no additional cleaning piping is needed. 

Once the CO2 is collected from the fermentation tanks via the Pentair Südmo Valve Tank Tops, the gas is directed to the Pentair Südmo Double-Seat Valve Gas Manifold, a centralized gas and CIP (cleaning in place) media distribution system. From there, the gas can be sent to either a foam trap or a vent trap (if the purity of the CO2 is insufficient for harvesting). The foam trap ensures that the raw fermentation gas is transferred to the Pentair Haffmans CO2 Recovery system foam-free.


CO2 Recovery 

After the initial fermentation process, the raw, foam-free gas is sent to the CO2 recovery plant. Here, it is buffered and scrubbed of water-soluble contaminants (like ethanol). The gas pressure is then increased to 18barg (261psig) using a two-stage CO2 compressor unit, removing condensate. The remaining impurities are removed using a dual-activated carbon filter and drier unit. 

At the end of the recovery process, the CO2 is liquified and stored in a liquid storage tank. From there, the CO2 can either be exported or sent to the vaporizer, where the CO2 will be processed into gas form and sent to the CCT and BBT (bright beer tank) area to be utilized back into the brewing process.

Results

Tennent’s Brewery previously needed to buy approximately 4,000 tonnes of CO2 per year (or 1.8kg of CO2 per HL) from third-party sources, which they also needed to vent into the atmosphere due to the brewing production process.

TENNENT'S BREWERY NOW

Recovers over 4,200 tonnes of its own CO2, repurposing 95% of this CO2 back into its brewing processes and eliminating the need to source CO2 from third-party sources.

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