Rate-based simulation and techno-economic analysis of coal-fired power plants with aqueous ammonia carbon capture

Ammonia is a promising solvent for the chemical absorption of carbon dioxide owing to its characteristics of low toxicity, low degradation, low cost, and low heat of desorption. The present work evaluates the energy and economic performances of the aqueous ammonia technology applied to a coal-fired power plant. First, the kinetics of absorption are characterized in the Aspen Plus software and are calibrated against the experimental data from the Munmorah pilot plant. Then, the validated model is used for sizing the full-scale plant columns and for simulating the overall capture plant. After determining the sizes of the plant components and their energy consumptions, the capture plant is integrated with the coal-fired power plant, and the economic analysis is assessed with both retrofitted and green-field approaches as described in reports from the European Benchmarking Task Force and the United States National Energy Technology Laboratory, respectively. The novelties presented here are the new approach in the absorption reactions implemented in the rate-based model, which changes the dependency of the ammonia concentration in the absorption process, as well as the full economic analysis with both retrofitted and green-field assumptions, which enable a sound comparison of the outcomes. The results with the retrofitted approach compared with the monoethanolamine case of the European Benchmarking Task Force report returned higher electric efficiency (36.3% versus 33.50%), lower levelized cost of electricity (87.66 €/MWhel versus 92.27 €/MWhel), and lower cost of carbon dioxide avoided (47.03 €/tonCO2 versus 51.62 €/tonCO2). The results using the green-field approach compared against the Cansolv case of the National Energy Technology Laboratory report returned higher electric efficiency (33.06% versus 32.50%), lower cost of electricity (124.3 $/MWhel versus 133.2 $/MWhel) and lower cost of carbon dioxide avoided (66.5 $/tonCO2 versus 75.25 $/tonCO2). In both comparisons, aqueous ammonia had appreciably better performance than the ammine reference cases