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.

The objective of this research is to reduce fines inside a novel comminution machine. Fines are detrimental to the energy efficiency of the comminution process and induce additional wear. An experimental setup was developed and built, the slice rig (SR), to obtain air flow measurements and mass rates which are used to determine the energy efficiency of the fines extraction.

The severe rise in global surface temperature and its associated damages to the ecosystem are primarily attributed to anthropogenic carbon dioxide emissions. The present CO2 levels in the air today and the continuing emissions necessitate even the most ambitious development scenarios to rely on net negative CO2 emissions to limit the global temperature rise to 1.5 °C until the year 2100. Direct Air Capture (DAC) refers to the direct extraction of carbon dioxide from the ambient air and addresses the need for net negative emissions. As the technology is still in its infancy, understanding and modeling the occurring processes is crucial.
This thesis addresses the challenges in modeling adsorption and desorption processes in solid-sorbent Direct Air Capture, focusing on the complexities introduced by the porous structures of sorbent materials and the effects of humidity. Current models fail to incorporate the full spectrum of mass transfer processes, or do not consider the significant effects of humidity on the process. To bridge this gap, a detailed mass transfer and reaction kinetics model at the particle scale was developed, aiming to provide a more accurate framework for predicting the performance of amine-functionalized sorbents in DAC applications. The model was developed on a particle scale, and subsequently included in contactor models of a packed-bed and a monolith. The study considered all relevant transport mechanisms, finding that pore diffusion and reaction kinetics are critical in governing sorbent uptake dynamics. The contactor model effectively compares the performance of packed-bed and monolith reactors, highlighting a tradeoff between productivity and energy efficiency, with significant potentials for energy savings offered by the monolith.

While CO₂ is one of the factors increasing the global temperature, it is also utilized in the agriculture to enhance crop yield. In the agriculture, a sustainable solution to CO₂ mitigation would potentially lie in the greenhouses. A moisture swing direct air capture system can adsorb CO₂ from the air through changes in humidity levels between the adsorption and the desorption stages. During adsorption dry air is required, while during desorption humid air is required. In a greenhouse, where humid air is typically required for the crops and CO₂ enhancement is often achieved through fossil-fuel combustion, a moisture swing system could be a sustainable innovation.

Insights into the feasibility and potential implementation of a moisture swing column designed to enhance CO₂ concentrations within a greenhouse are obtained through an investigation of the key parameters of the sorbent, the effect of global climate conditions on the sorbent, a parameter sensitivity analysis of the performance of the system, and a preliminary techno-economic viability assessment.

A one-dimensional numerical model was developed to solve the mass balance of a cylindrical adsorption column. Critical key parameters that affect the CO₂ saturation coverage of the sorbent are the gas phase CO₂ concentration, the relative humidity, and the temperature. Investigated is how these conditions vary globally, highlighting optimal arid climate regions with a high saturation coverage. It was found that seasonal and diurnal deviations are significantly higher in regions where a lower saturation coverage can be reached. From the sensitivity analysis of the parameters and conditions, it was that a 1.6-meter-long column achieved a system efficiency of 15.0 micromoles of CO₂ per kilogram sorbent per second, a water loss of 45.4 moles of water per mole of CO₂, and a system productivity of 9.05 moles of CO₂ per second. In the short term, the majority of costs are attributed to the capital expenditures, whereas in the long term, operational expenditures become the dominant expense.