Moisture Swing Direct Air Capture for Carbon Dioxide Enrichment in Closed Greenhouse Environments

Moisture Swing Direct Air Capture for Carbon Dioxide Enrichment in Closed Greenhouse Environments

Vianen, Jop (TU Delft Mechanical Engineering)

Nijssen, Tim M.J. (mentor)
Vlugt, T.J.H. (graduation committee)
Keviczky, T. (graduation committee)

Delft University of Technology

Mechanical Engineering

2024-06-25

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.

Moisture Swing
Direct Air Capture
DAC
Greenhouses
Carbon Dioxide
CO2 enrichment

http://resolver.tudelft.nl/uuid:12b73950-3bb7-4e55-b799-b9e283ddc145

Student theses

master thesis

© 2024 Jop Vianen