Salt River Project and Arizona State University sponsored Direct Air Capture of CO2 Engineered Design
During our recent effort, sponsored by the 2017/2018 SRP Joint Research Program, Dr. Lackner and several students developed the engineering and supporting documentation for two CO2 Direct Air Capture (DAC) collectors. This SRP supported engineering effort was a dramatic step forward from our lab scale demonstration of a technology that can collect CO2 from ambient air and produce a clean gas stream with CO2 concentrations up to 5%. The outcomes of the joint SRP/ASU engineering project has provided measurable progress towards selection of the ideal design integrated with downstream processes to enrich and upgrade CO2 for commercial product applications. During the sponsored program, ASU expanded on two conceptual designs, completing the engineering required as a preliminary to prototype fabrication. The engineering and economic analysis highlighted the need for additional engineering and modeling to expand one of the design concepts into clusters of units that are integrated for enhanced CO2 recovery and to feed a CO2 concentration and purification system.
The Tiburio batch design, as shown above, collects CO2 when raised above a circular chamber, and harvests the CO2 when the fabric material is inside the sealed chamber. The Continuous Loop Design, shown below, harvests CO2 within a chamber. As air passes over the belt (the absorption material) CO2 is collected. Than the belt will move into the Chamber across water to prepare the belt for the CO2 harvest. This water chamber, or U-tube, will act as a natural seal for the system. In the chamber, an air flow will “harvest” the CO2 and deliver the CO2 mixed with air to a secondary tank or application (such as a greenhouse).
One of the most powerful means of cost reductions is mass-manufacture of goods. As a result, ASU is designing the capture equipment to be built in a fabrication facility and to be mass produced to satisfy potentially large demand. Equipment with large size and weight introduces several challenges including fabrication costs, less “off the shelf” procurement and restrictions on siting. Therefore, rather than scaling up in size, we will scale up in quantity. While this may not reduce cost for the first-of-a-kind device, it will create consistent reduction in cost as more air capture technology is produced. This decision keeps the size of the device relatively small and meets our requirement that the final device be packaged into a standard shipping container (or two) so that it can easily be delivered to its point of use. Therefore, design will focus on “off the shelf” parts, equipment and material.
We have been awarded for the second grant to collaborate with SRP on 2018/2019 Joint Research Program expand on our design and engineering of DAC prototypes. The ASU team is planning to work two areas that need resolution for the Tiburio capture device. First, we will group the Tiburio into skid that can be joined with other skids to produce large amounts of captured CO2. Secondly, we will select the best suited options for downstream CO2 concentration and purification. For these efforts ASU will continue to focus on restraining the cost of fabrication and O&M.