Gregory V. Lowry

Removing CO₂ from air (air capture) using a NaOH-based Scrubber

Funding Agencies
Pennsylvania Infrastructure Technology Alliance

National Science Foundation

Collaborators
David Keith, CMU (EPP)

Publications

Stolaroff, Joshuah K., Lowry, Gregory V., and Keith, David W. (2004). “CO₂ extraction from ambient air using alkali-metal hydroxide solutions derived from concrete waste and steel slag.” In the Proceedings of the Fuel Chemistry Division, 227th American Chemical Society National Meeting, Anaheim, CA, March 27-April 1. Vol. 49. No. 1.

Stolaroff, J. K., Lowry, G. V., Keith, D. (2006). Experimental measurement of energy requirements for capturing CO2 from ambient air in a pilot-scale system. GHGT8, Eighth International Conference on Green House Gas Control Technologies, Trondheim, Norway. June 19-22, 2006.

Abstract

Fossil fuel use in the 21^st century will be limited by environmental constraints. The potential for carbon emissions is far larger than what the atmosphere, the oceans or the biosphere could absorb without severe environmental consequences. Within half a century, the world must move roughly half way towards a zero net-CO₂ energy system; emissions must be reduced by at least fifty percent of today’s output by 2050. This could be accomplished by gradually eliminating the use of fossil carbon in the energy sector, or by capturing carbon dioxide, either at the source or from the air, followed by its permanent and safe disposal (sequestration). While large-scale deployment of low carbon technologies may be decades away, the enormous technological inertia of energy infrastructures dictates that action to develop and test such technologies must begin now if we are to achieve cost-effective solutions to the CO₂ climate problem.

Research on industrial carbon management has focused on capturing CO₂ from large centralized facilities such as electric power plants because of the higher CO₂ concentrations emitted from these sources. Recent published studies by this team have demonstrated that it is possible to capture CO₂ directly from the ambient air. The feasibility and cost of large-scale CO₂ capture from air by this approach are, however, uncertain and somewhat controversial. The proposed CO₂ capture scheme uses a concentrated NaOH-based contactor to remove CO₂ from ambient air, then uses a commonly used chemical recovery method (Kraft process) to regenerate the NaOH absorbing stream. CO₂ captured by a calciner in the process is concentrated and made ready for geologic storage. Despite considerable industrial experience with these types of processes, it is far from clear what an optimal contactor would look like and what the rate limiting steps are for a contactor design involving strong alkaline solutions. Similarly, it is uncertain how to design and operate a CO₂ emission-free calciner capable of producing a concentrated pressurized CO₂ stream for sequestration. We propose to tackle these uncertainties head-on through a suite of the scientific and engineering analyses and laboratory experiments that will enable a robust assessment of the cost and feasibility of large-scale air capture.

Greg Lowry Home | Dept. Civil & Env. Engr.
Last Modified: June 2003