3 research outputs found
Multiparametric Study of Water–Gas Shift and Hydrogen Separation Performance in Membrane Reactors Fed with Biomass-Derived Syngas
No full textA multiparametric study was conducted on a hydrogen (H2) production rig designed to process 0.25 nm3·h−1 of syngas. The rig consists of two Pd-Ag membrane permeator units and two Pd-Ag membrane reactor units for the water-gas shift (WGS) reaction, enabling a detailed and comprehensive analysis of its performance. The aim was to find the optimal conditions to maximise hydrogen production by WGS and its separation in a pure stream by varying temperature, pressure, and steam-to-CO ratio (S/CO). Two syngas mixtures obtained from an updraft gasifier using different gasification agents (air-steam and oxy-steam) were used to investigate the effect of gas composition. The performance of the rig were investigated at nine combinations of temperature, pressure, and S/CO in the respective ranges of 300 - 350 °C; 2 - 8 bar; 1.1- 2 mol·mol−1 as planned with the help of a design of experiment (DOE) software. The three parameters positively effected the performances, both as capacity of separating a pure stream of H2 reported as moles permeated per unit of surface area and time, and producing new H2 from WGS, reported as moles of H2 produced per volume of catalyst unit and time. The highest yields were obtained using syngas from oxy-steam gasification, which had the highest H2 concentration and was free of N2
Air-steam and oxy-steam gasification of hydrolytic residues from biorefinery
No full textThis paper reports the use of lignin-rich solid, derived from enzymatic hydrolysis of lignocellulosic biomass, to produce syngas and pyrolysis oil. The tested process was an updraft gasification carried out at pilot scale of about 20 kg/h as solid feed. The reactivity of two residues, one from straw and one from cane, was investigated by TGA in air, oxygen, nitrogen, using a heating program simulating the thermal gradient in the gasifiers. Below 400 °C the residues completely burned in air or oxygen with an apparent reaction order of 0.1–0.2. The 75%–80% of the organic mass was pyrolysed at 700 °C, when the gasification with H2O and CO2 started. In the plant tests, the residue was completely converted in gaseous and liquid energy carriers with an overall energy efficiency of up to 87%. Ten conditions were examined with different air flow (19.0, 25.5, 26.5 kg/h), O2 (4.0, 4.5, 5.5 kg/h) or H2O (as steam at 160 °C: 1, 2.5, 4.0, 4.5, 5.5, 8.5 kg/h). The experimental data were analyzed using the Response Surface Analysis (RSA) in order to highlight the dependence on the Equivalence Ratios of oxidation. The molar ratio H2/CO in the syngas increased by using steam as co-gasification agent, and reached the value of 2.08 in oxy-steam gasification. Steam was necessary to stabilize the process when using oxygen as it was effective in lowering the average temperature in the gasifier. Another positive effect of using steam was the shift of the temperature maximum far from the grate where ash melting could occur. Oxy-steam gasification provided the best results in terms of syngas heating value (LHV 10.9 MJ/m3) and highest thermal power output of the plant (67 kWth). The tar yield was inversely correlated with the residence time of the gas in the bed, in according with a zero order reaction for tar cracking into incondensable hydrocarbons and hydrogen. © 201
Civilização e barbárie na ciência do direito internacional: discursos e representações de conceitos entre os séculos XVI e XIX
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Jurídicas, Programa de Pós-Graduação em Direito, Florianópolis, 2015.A compreensão dos conceitos articulados no âmbito de um discurso permitem desvelar práticas ideológicas e de dominação. No discurso jurídico internacionalista, os conceitos de ?civilização? e ?barbárie? cumpriram o papel de manipular a forma como os povos não europeus eram retratados e a partir dessa representação, estabeleciam estratégias de subjugação. Desde o lançamento de suas bases, no século XVI, até o seu definitivo estabelecimento como disciplina autônoma no século XIX, o direito internacional utilizou desses conceitos para articular um direito hierarquizado, mas ocultado pela retórica universalista. Na presente pesquisa, utiliza-se do instrumental metodológico da ?história dos conceitos?, de Reinhart Koselleck, como chave de compreensão dos conceitos de ?civilizado? e ?bárbaro? no âmbito do discurso jurídico internacionalista, do século XVI ao XIX. Importou, então, historicizar os conceitos, reconstruindo suas gêneses, para alcançar todas as possibilidades semânticas que o conceito pôde assumir dentro do discurso. Assim, foi formulada a gênese do conceito de ?bárbaro? e investigado sua articulação com o nascente direito das gentes no século XVI. Em seguida, o conceito de ?civilizado? foi abordado, bem como a manipulação do mesmo nos textos jurídicos da transição do século XVI ao XVII. Enfim, analisou-se a ressignificação dos conceitos acarretada pelo aparecimento da palavra ?civilização? no século XVIII, e a nova configuração do discurso jurídico internacionalista. A manipulação dos conceitos pela doutrina do direito internacional concebia um direito hierarquizado, em que os povos não europeus eram colocados em uma relação assimétrica, que possibilitava sua subjugação através de retórica jurídica.Abstract : The comprehension of concepts articulated inside a discourse permits reveal ideological and domination practices. In the international legal discourse, the concepts of civilization and barbarism played a role of manipulating the way non-European peoples were depicted, e from that representation, it could be established strategies of subjugation. Since its foundational texts, in sixteenth century, to it definitive establishment as an autonomous discipline in the nineteenth century, international law had utilized these concepts to articulate an hierarchical law, covered, however, by an universalistic rhetoric. In the present research, it is utilized the ?conceptual history?, by Reinhart Koselleck, as a key to comprehend the concepts ?civilized? and ?barbarian? in the international legal discourse, from sixteenth to nineteenth century. It was important, to historicize the concepts, reconstructing their genesis, to attain all the semantic possibilities that the concept can assume inside a discourse. Thus, it was formulated the genesis of the concept of ?barbarian? and investigated the articulation with the rising droit de gens of sixteenth century. Then, the concept of ?civilized? was approached, as well as the manipulation of it in the legal texts in the transition from the sixteenth to seventeenth century. Finally, it was analyzed the resignification of concepts entailed by the emergence of the word civilization in the eighteenth century, e the new configuration of international legal discourse. The manipulation of concept by the international legal discourse conceived a hierarchical law, under which non-European peoples were placed in an asymmetrical relationship, enabling their subjugation by a legal rhetoric
