Carbon Dioxide Adsorption via Ultra-High Surface Area Carbon

In this Phase 1 project, Vuronyx Technologies investigated the use of a high surface area carbon for adsorption of carbon dioxide. Current industry practice of CO2 capture is by using amine-based scrubbing systems via absorption–regeneration technology. The amine solvent binds with the CO2 generated during coal combustion in the absorption reactor, and is sent to a stripper column for solvent regeneration and recycling. The separated CO2 is then cooled and transported for compression and sequestration. Amine based CO2 removal is energy intensive and not cost-effective due to the energy penalty associated with the stripping of CO2 and regeneration of solvent. The innovative carbon powder investigated by Vuronyx Technologies in Phase 1 is based on stabilization and carbonization of polyacrylonitrile powder – similar high temperatures steps are used in the manufacturing of carbon fibers. In Phase 1, we evaluated the effect of process parameters on the adsorption of carbon dioxide from a carbon dioxide and nitrogen mixture, using an experimental setup developed in-house. Various parameters such as temperature, carbon dioxide content, and surface functionalization of carbon fiber were evaluated to understand their effect on carbon fiber adsorption. Finally, a cost analysis was performed to understand the feasibility of using high surface carbon powder for carbon dioxide adsorption from flue gas. The activated carbon powder synthesized in Phase 1 has surface area > 3200 m2/g. We have shown that our high surface area carbon adsorbs >23 mL (median value of 50 measurements) of carbon dioxide per gram of activated carbon powder, which is ~40% higher than commercially available high surface area carbon (Kurraray YP-150F). The adsorption-desorption experiments showed that the activated carbon is fully regenerated over 50 cycles conducted here. Compared to solvent based systems, solid sorbents such as activated carbon have reduced requirements for sensible heating and stripping energy, which can lower overall operating costs. This Phase 1 effort was directed towards estimating the improvement in carbon dioxide adsorption with a high surface carbon. The experimental data and cost analysis in Phase 1 has shown that activated carbon is indeed a promising approach for carbon dioxide adsorption; however further optimization of activated carbon and pore size distribution is required for their cost-competitiveness with respect to solvent based carbon dioxide adsorbents. Development of cost-effective materials and process for carbon dioxide capture will enable cheaper electricity rates. In the foreseeable future, a majority of electricity requirement of USA and globally will be met with coal fired plants. Despite concern of global warming, the use of coal has continued to increase globally. Carbon capture from major CO2 emitting industries like coal-fired power plants and fossil-fuel based plants is one of the immediate options to address the issue of increasing carbon dioxide concentrations in the atmosphere. Cost-effective adsorbents such as activated carbon pursued in this Phase 1 effort can be a viable approach for eliminating carbon dioxide from atmosphere.