Project Description:
The goal of this project is to create a direct air capture device which utilizes a vacuum moisture swing technique to extract CO2 from air. The CO2 capture will be achieved by a sorbent bed, with structured sorbent beds developed and tested against the performance of a packed bed. The vacuum moisture swing device will function by pushing air through the sorbent bed, resulting in cleaner air exiting. A vacuum will then be pulled, which will cause a reservoir of water at room temperature to vaporize. The water vapor will be pulled through the sorbent bed, causing the CO2 to unbind from sorbent. The CO2 will be carried downstream and contained. The cycle will then repeat. The dynamics of the vacuum moisture swing process have already been calculated and simulated by the NAU Climate Solutions Lab, and will inform many of the parameters of the cycle. For this project, the team will focus on optimizing the sorbent bed and designing a functioning and automated vacuum moisture swing direct air capture (DAC) device. The project’s client is Dr. Jennifer Wade. SRP is sponsoring the project, and have promised $50,000. To satisfy our fundraising requirement, we have applied to the NAU Green Fund for a $2000 grant and are currently awaiting approval. Based on early budgeting, this total will be more than sufficient for completing the full project. This project is important as a proof-of-concept of a novel method of removing CO2 from air. CO2 is the largest contributor to global warming and ocean acidification. The client intends for the design to be scaled up in the future to provide a method of extracting CO2 from the air near factories. If the vacuum moisture swing design proves to be effective and energy efficient, it could be deployed near many factories and other CO2-producing facilities and significantly decrease CO2 emissions.
Engineering and customer requirements
Deliverables:
The two primary deliverables for the client are structured sorbent beds and a vacuum moisture swing device. The structured sorbent beds must perform better than a standard packed sorbent bed. The vacuum moisture swing device must be capable of testing a wide range of sorbent beds while maintaining the temperature and speed conditions that the client has specified. Further deliverables for the device are that it must be automated, maintain a clean lab environment, and output the data to Matlab. The ME476C course deliverables are to complete three presentations, two reports, several individual learning assignments, and weekly timecards and staff meetings. In addition, the team has set client deliverables of meeting with the mentor every week and the client biweekly.
Success Metrics:
Success for this project will be based on two categories: the structured sorbent beds and the vacuum moisture swing device. Success in structured sorbent beds will be assessed by creating one which performs better than the baseline of a packed sorbent bed. The proposed designs will have computational fluid dynamics performed with ANSYS to simulate airflow through them. Designs successful in simulation will then be tested in the vacuum moisture swing device. Success of these structures will be analyzed by observing the pressure drop, and the adsorption efficiency, based on pressure transducers and gas analyzers. The pressure drop must be lower than the packed bed, and the adsorption capacity must be reasonably close to the packed bed. Testing will therefore include a packed bed to obtain the baseline numbers which will be used to analyze success of the structured beds. Success in the vacuum moisture swing device will be based on whether it can create and maintain the conditions desired for the vacuum swing process. Calculations will be performed to identify the ideal velocity and pressure during the adsorption and desorption processes. The client has already identified the steps in the cycle (being adsorption, evacuation, desorption, final evacuation, and pressurization). The device must cycle through these steps properly, opening and closing valves, powering on and off pumps and heating elements, and recording data from sensors throughout the process. If the device can perform the full vacuum moisture swing cycle on all of the sorbents that are tested, it will be a success.
Current Status:
The status of the design is a structured diagram with many final components selected. Several parts such as sensors, the condenser and the vacuum pump are undergoing their final selection process to soon be ordered for assembly, A 3D printer has also been selected and is currently being proposed to green fund to acquire the necessary funding. ANSYS simulations have been performed to begin optimizing sorbent structures for final testing. Soon all parts will be ordered, and the rig will be assembled to begin testing and dial in the PLC loop. ANSYS simulations will become more detailed to find the best structures to physically test. Lastly the printer will hopefully be funded so these optimized structures can be printed out and physically tested.