(747d) Analysis of Warm Membrane- and Adsorbent-Based Carbon Dioxide Capture Technologies for IGCC

Integrated Gasification Combined Cycle (IGCC) power generation is a promising technology to address the capture of carbon dioxide produced from coal feedstocks. IGCC plants operate at much higher pressures than traditional subcritical pulverized coal plants, creating smaller volumes and larger concentration gradients that facilitate the separations process. Unfortunately, current state-of-the-art carbon dioxide capture technologies must be performed at or below room temperature, resulting in higher capital costs and greater efficiency losses as the hot process gas is cooled, cleaned, and then reheated for further processing downstream. Two suggested methods to address this problem are the use of membranes or solid adsorbent materials that can operate at elevated temperatures. However, no commercial processes exist for these high-temperature separations, and the potential gains in efficiency that could arise from the use of these elevated-temperature technologies are not well-known. Candidate membrane and sorbent materials can be tested on a pilot scale, but this process is both time-consuming and expensive. Here we present an alternative approach in which we evaluate the feasibility of different membrane and sorbent processes for carbon dioxide capture and sequestration through the use of computational simulations. We model multicomponent gas separation in membranes through the use of Pd-based composite metallic membranes for hydrogen separation or polymeric membranes for carbon dioxide separation. In addition, we model the chemisorption and regeneration processes of carbon dioxide on solid sorbent materials using a numerical pressure-swing adsorption model. We then integrate our model results within an IGCC process model developed within Aspen Plus to identify the optimal operating conditions for the membrane and adsorption technologies within the IGCC plant. These results can then be used to evaluate the most promising technologies for the separation of carbon dioxide at elevated temperatures. In addition, we can use the results we obtain to suggest the necessary material properties of the promising membrane and sorbent technologies, potentially providing direction for ongoing experimental work with these materials.