Browsing by Author "Dias, Ricardo N."
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- Decision-making based on sustainability analysis using GREENSCOPEPublication . Dias, Ricardo N.; Filipe, Rui; Matos, Henrique A.Current economic and environmental pressure encourages companies to invest and reform processes in a sustainable way. However, the decision on the best sustainable investment in a given industry may not be as straightforward as given by the independent economic and environmental indicators. Analyzing such indicators for investment in process alternatives is a complex multi-objective decision-making process. Many methods can help solve multi-objective problems, GREENSCOPE suggests using the Addictive Utility Method, which may have some shortcomings. In this work, the Analytic Hierarchy Process and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) are applied to the indicator scores obtained with the GREENSCOPE methodology. The Analytical Hierarchy Process is applied with Marginal Rate of Substitution, to obtain the priority matrices. MATLAB was used to apply the methods and through an algorithm, to determine the adequate number of indicators to be used. Three cases were studied, namely a biorefinery plant, and two academic case studies on the production of acetaldehyde from ethanol and propylene glycol from glycerol. The two academic cases were modeled in Aspen Plus, to obtain process data, and linked to GREENSCOPE using MATLAB. The methodology was applied to some proposed alternatives where the sustainability improvement of energy integration and material recycling was tested. The new methodology was able to identify the more sustainable case among the alternatives. This methodology based on TOPSIS proved to be the best choice, avoiding the weighting of indicators, and providing an expected analytical decision among alternatives.
- Sustainability analysis of a solar-driven calcium looping plant for thermochemical energy storagePublication . Dias, Ricardo N.; Filipe, Rui; Matos, Henrique A.Sustainable development is essential to ensure that future generations enjoy the same or better standard of living as today's society. Clean energy will play an important role in this. Concentrated solar power is one of the cleanest ways to harness solar power and convert it into useable energy like electricity. However, due to the intermittent nature of solar power production, concentrated solar power needs to be coupled with energy storage to ensure the ability to produce and release electricity during peak demand periods. Calcium looping for thermochemical energy storage is an emerging technology that uses calcium carbonate, a highly abundant and inexpensive material, to store energy in the form of calcium oxide and carbon dioxide. A sustainability analysis of a solar-driven calcium looping plant for thermochemical energy storage process is performed in this work. Several process alternatives, previously modelled in Aspen Plus (R), are assessed using three sustainability analysis tools, GREENSCOPE, SimaPro, and OpenLCA. Nine process alternatives are considered, including the use of sorbent purge, water vapor as fluidization fluid at the calciner, and different operating temperatures in the calciner. All the analysis tools identified the process alternative using total sorbent purge, water vapor as fluidization fluid and a calciner temperature of 800 degrees C as the best overall performer. This work contributes through a sustainability analysis to the decision-making on which process configuration and conditions should be used, building on a previous technical analysis of a calcium looping for thermochemical energy storage process.