To combat climate change, industries across the board must transition to renewable practices and reduce their reliance on fossil-derived resources. The beer brewing industry, in particular, faces a significant challenge as it depends heavily on food-grade CO₂, which is typically produced through the combustion of fossil fuels. However, biogenic CO₂ is generated naturally during the fermentation step of the brewing process, presenting a renewable alternative source. Whilst large-scale breweries have successfully adopted systems to capture and upgrade this biogenic CO₂ to food-grade standards, these technologies remain economically unfeasible for smaller craft breweries that typically produce fewer than 10,000 hectoliters of beer annually. As a result, many craft brewers continue to rely on CO₂ suppliers who source their product from fossil fuels, maintaining their dependence on non-renewable resources. Furthermore, they stay dependent on the CO₂ market, in which CO₂ might become a more expensive resource.
This thesis focuses on the design and economic evaluation of a novel, cost-effective fermentation gas purification system specifically for small-scale craft breweries. The process includes identifying the necessary separation steps based on the composition of fermentation gas, determined through a literature review, alongside an analysis of regulatory requirements defining the food-grade CO₂ standard. Suitable technologies are selected based on their operational ranges and effectiveness for the required separations. These technologies are then ordered and designed in the appropriate sequence. The design process yields critical outputs such as equipment sizing, operational conditions, and energy requirements. These parameters serve as inputs for an economic analysis, which estimates the capital and operational expenditures of the system. This analysis is subsequently used to assess the economic viability and overall cost-effectiveness of the proposed solution.
The results contribute to bridging the technological gap, offering small-scale breweries a sustainable pathway to independently produce food-grade CO₂, reducing their reliance on external suppliers and associated emissions. By adopting this system, the craft beer industry can take a significant step toward achieving carbon neutrality.