1,721,115 research outputs found
LCA Analysis of Different MSW Treatment Approaches in the Light of Energy and Sustainability Perspectives
No full textThis study concerns with a theoretical investigation on the disposal and valorisation of Municipal Solid Waste
(MSW) through a challenging approach, based on the separation of MSW into two different fractions: Refuse
Derived Fuel (RDF) and Organic Fraction Municipal Solid Waste (OFMSW). Both fractions are energetically
valorised through gasification and anaerobic digestion (AD) processes respectively, in both cases gas streams
were burned to produce electrical and thermal energy. The sustainability of the processes from the
environmental as well as the energetic point of view, has been pursued, to find out if it can represent a viable
alternative to the problem raised by the management of MSW and their landfill containment. Following the Life
Cycle Analysis (LCA) approach, each stream of the processes has been analyzed in order to evaluate the
environmental performances. On the other hand, the energy sustainability analysis has been carried out
following the evaluation of two indexes: the Energy Sustainability Index (ESI) and the Energy Return of
Investment (EROI). Results highlight that this process is more sustainable than landfill technology, in particular
for “global warming”, “photochemical oxidation” and “eutrophication” impact parameters of CML2001, and
categories connected with “Human Heath” of Eco-indicator99 method; the comparison with traditional landfill
option shows that the environmental impacts are less than 10%. The proposed MSW treatment approach is
less sustainable than landfill for only two categories: “acidification/eutrophication” and “minerals”. In merit to
the energy sustainability analysis, the system results to have a positive merit: it produces a surplus of “Useful
Energy”
Dynamic modelling of methanation reactors during start-up and regulation in intermittent power-to-gas applications
No full textPower-to-gas is a pathway for the storage of intermittent renewable energy in a chemical form; energy surpluses can be exploited to produce hydrogen (via electrolysis) that can then react with carbon dioxide to produce synthetic methane by using catalytic cooled reactors. Methanation unit has been designed and optimized, defining the number of involved reactors, the number of parallel tubes for each reactor and the staged CO2 injection to moderate the maximum temperature throughout the reactors. The produced synthetic natural gas (SNG) must have a methane content at least equal to 95 mol.-%, achieved by involving a series of 3 cooled reactors. Dynamic behavior of the as-designed system has been investigated for two cases that can occur when a power-to-gas system is operated intermittently: start-up from reactor hot standby and system operated at partial load. Methanation system requires about 130 s to reach the targeted methane content when it is started up from hot standby. In order to broaden the system rangeability (the minimum percentage of full load), different CO2 staged injection should be carried out: part of carbon dioxide bypasses first and second reactor and it is directly conveyed to the third one
Thermodynamics of cis,cis-muconic acid solubility in various polar solvents at low temperature range
No full textWet Air Oxidation of Acetovanillone over LaFeO3 as Catalyst: A Model Reaction for Lignin Valorization
Full text linkWet air oxidation (WAO) of lignocellulosic biomasses is a promising route for the production of renewable and valuable compounds. In this work, acetovanillone (AV) was selected as lignin model molecule in order to investigate its behavior under the WAO reaction conditions. The experiments were carried out in a pressurized 50 ml batch reactor loaded with NaOH 2M as solvent, the reaction takes 1 h with temperatures ranging from 130 to 190 °C and air pressures between 5 and 30 bar. The perovskite-type mixed oxide LaFeO3 was synthetized and used as heterogeneous catalyst in order to improve the activation of molecular oxygen. Vanillin yield resulted to benefit from high reaction temperature showing a maximum carbon yield of 22%, instead the formation of carboxylic acids from the oxidative degradation of AV largely benefits from high pressure of air, exhibiting an overall carbon yield of 35%. The produced compounds include oxalic, glycolic, lactic, malonic, and levulinic aci
Hydrodeoxygenation of guaiacol over Mo-based catalysts: A model reaction for the upgrading of lignin-derived bio-oils
No full textA novel pH uncontrolled route for the synthesis of adipic acid from glucose over Pt/alumina catalyst
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