1,720,976 research outputs found
Mercury adsorption on activated carbon in Waste-to-Energy: Model development and validation on real plant data
No full textA model capable to estimate the mercury (Hg) removal efficiency in the fabric filter of a real Waste-to-Energy plant with dynamic operating conditions has been developed. The mathematical model is based on Langmuir equation and Hg mass balance on mercury, in both gaseous and adsorbed phases, along the growing filter cake and inside the activated carbon particles. The activated carbon properties and the Langmuir isotherm parameters have been obtained by fitting the model to real plant data, characterized by variable mercury inlet concentrations. The model is then validated on another dataset coming from the same plant. The obtained Hg removal efficiency falls within +/- 3 % error band and with a mean absolute percentage error equal to 0.87 %. The model is suitable for the development of a datadriven activated carbon feed control strategy to increase the economic and environmental sustainability of the WtE plants as well as in the development of virtual sensors to use as a replacement when the continuous stack mercury monitors fail
Numerical modelling and process simulation of a post-combustion CO2 capture pilot plant based on a membrane contactor unit
No full textBench-scale experimental tests and data analysis on CO2 capture with potassium prolinate solutions for combined cycle decarbonization
No full textThe present research work provides a quantitative evaluation of the CO2 absorption performance of potassium prolinate by setting a reliable and cost-effective approach for solvent screening, based on both experimental activities and data analysis. Potassium prolinate has been chosen as a promising green solvent to be tested at two different concentrations (30% and 43.38% w/w ProK aqueous solutions). The applied methodology involves direct comparison of the alternative solvent against a reference case, such as 30% w/w MEA solution. The test has been carried out on a bench-scale facility composed of a glass column with internal random packing located at Sotacarbo Research Center (Sardinia); the facility has been run in open and closed cycle mode, assessing the performance in terms of CO2 removal from NGCC synthetic flue gases (e.g.: 4% mol/mol CO2 concentration). The outcome of this work provides new information based on experimental data on removal, maximum achievable loading, loading increment rate and solvent capacity, and it constitutes a novel contribution to the literature. Moreover, it represents a tangible effort in delivering an insight on non-precipitating amino acid viability for flue gas decarbonization in CCS technologies
Energy storage scenarios and design of a new Italian innovation infrastructure for energy transition
No full textBio-methanol with negative CO2 emissions from residual forestry biomass gasification: Modelling and techno-economic assessment of different process configurations
Full text linkThe paper presents a techno-economic comparison among five alternative process configurations for bio-methanol production from the gasification of residual forestry biomass. Process design and simulations are performed in Aspen Plus for mass and energy balance calculation, followed by preliminary sizing and economic analysis. Process schemes include a gasification island (state-of-the-art low-pressure gasification compared against a high-pressure gasifier) with syngas conditioning and compression, heat recovery, syngas composition adjustment (by CO2 capture or addition of hydrogen produced by electrolysis), methanol synthesis and purification and a heat recovery cycle for power generation. CO2 capture is performed with conventional chemical absorption in the benchmark cases, while low-temperature partial condensation of CO2 is modeled in the advanced scenario. Methanol output is 14–15 kt/y in the CO2 capture cases and 36 kt/y in the H2 addition option. Configurations with a pressurized gasifier and phase-change-based CO2 separation are the most efficient ones, with a primary energy efficiency of 50 % and a Levelized Cost of Methanol (LCOM) of 700 €/t_MeOH. In comparison, LCOM increases to 730 €/t_MeOH in the case with conventional capture or between 792 €/t_MeOH and 831 €/t_MeOH (depending on the CCS technology) if the gasification pressure is conservatively reduced to 2.5 bar. In the H2 addition scenario, LCOM increases to 821 €/t_MeOH due to the significant impact of the electricity consumption for H2 production, (only partly compensated by the increased methanol production). Scenarios with CO2 capture feature negative CO2 emissions, in the range −1.64 to −1.84 t_CO2eq/t_MeOH, as a result of the capture and storage of biogenic CO2 (BECCS approach)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
