Search results for "Biomas"

Rapid one-step solvent-free acid-catalyzed mechanical depolymerization of pine sawdust to high-yield water-soluble sugars

2017

Abstract One-step absolute solvent-free acid-catalyzed mechanical depolymerization of pine sawdust (PSD) and commercially available α-cellulose to water-soluble sugars was carried out using ball milling. For comparison purposes, the commonly reported “solvent-free” mechanocatalytic depolymerization of lignocellulose method, which normally involves three steps (acid impregnation in solvent, vacuum drying, and mechanical depolymerization of lignocellulose), was performed. The 3,5-dinitrosalicylic acid (DNS) method was used to measure the total reducing sugar (TRS) of the obtained sugar solution, and major monosaccharides in the solution were analyzed by capillary electrophoresis (CE). More th…

La evolución energética del sector español de baldosas cerámicas

2014

espanolEl presente texto analiza como ha ido evolucionando el consumo y la eficiencia energetica de la industria espanola de baldosas ceramicas durante el siglo XX, y explora las posibilidades que se le plantean en el siglo XXI. Durante el pasado siglo este sector industrial acometio tres transiciones radicales al pasar de los combustibles tradicionales de biomasa a los hidrocarburos liquidos (fueloleo y gasoleo), y posteriormente a los gaseosos, principalmente gas natural. Aunque la informacion que permite evaluar de manera fiable la eficiencia energetica real en las plantas de fabricacion no es facil de obtener, los datos disponibles indican que se ha llegado a una elevada eficiencia con …

Enhanced Heterogeneous Catalytic Conversion of Furfuryl Alcohol into Butyl Levulinate

2014

We study the catalytic condensation of furfuryl alcohol with 1-butanol to butyl levulinate. A screening of several commercial and as-synthesized solid acid catalysts shows that propylsulfonic acid-functionalized mesoporous silica outperforms the state-of-the-art phosphotungstate acid catalysts. The catalyst is prepared via template-assisted sol-gel polycondensation of TEOS and MPTMS. It gives 96 % yield (and 100 % selectivity) of butyl levulinate in 4h at 110 °C. Reaction profiles before and after a hot filtration test confirm that the active catalytic species do not leach into the solution. The catalyst synthesis, characterization, and mode of operation are presented and discussed. Sour ca…

Catalytic Activity of Char Obtained from Fast Pyrolysis in Esterification Reactions

2021

In this study different pathways for obtaining activated carbon with catalytical activity were analysed. Industrially fast pyrolysis is an efficient way of lignocellulosic biomass processing, since in this process various important high value chemicals are obtained. Biochar is obtained as the by-product in fast pyrolysis process from which activated carbon can be acquired with further chemical activation. Different methods for chemical activation of biochar were tested with the obtained activated charcoals being used as a catalyst in esterification reactions to evaluate their potential use as a heterogenic catalyst. Highest catalytical activity was observed when biochar was pre-treated with…

Nitrous oxide emissions in a membrane bioreactor treating saline wastewater contaminated by hydrocarbons

2016

The joint effect of wastewater salinity and hydrocarbons on nitrous oxide emission was investigated. The membrane bioreactor pilot plant was operated with two phases: i. biomass acclimation by increasing salinity from 10 gNaCl L−1 to 20 gNaCl L−1 (Phase I); ii. hydrocarbons dosing at 20 mg L−1 with a constant salt concentration of 20 gNaCl L−1 (Phase II). The Phase I revealed a relationship between nitrous oxide emissions and salinity. During the end of the Phase I, the activity of nitrifiers started to recover, indicating a partial acclimatization. During the Phase II, the hydrocarbon shock induced a temporary inhibition of the biomass with the suppression of nitrous oxide emissions. The r…

Lignin-based activated carbon-supported metal oxide catalysts in lactic acid production from glucose

2021

In this study, heterogeneous biomass-based activated carbon-supported metal oxide catalysts were prepared and tested for lactic acid production from glucose in aqueous solution. Activated carbons were produced from hydrolysis lignin by chemical (ZnCl2) or steam activation and modified with a nitric acid treatment and Sn, Al, and Cr chlorides to obtain carbon-based metal oxide catalysts. The modification of the carbon support by nitric acid treatment together with Sn and Al oxides led to an increase in lactic acid yield. The highest lactic acid yield (42%) was obtained after 20 minutes at 180 °C with the Sn/Al (5/2.5 wt.%) catalyst on steam-activated carbon treated by nitric acid. Reusabilit…

Ionic liquids: a highway with many lanes

Return of the Apex Predator : How Brown Trout (Salmo trutta) Re-Establishment Shapes an Ecosystem

2021

Re-establishment of a declined apex predator fish species in a lake ecosystem may have dramatic effects on other fish and plankton community already inhabiting the ecosystem. We studied mechanistically potential impacts of re-establishment of the brown trout (Salmo trutta) in the west-central European Lake Constance focusing on two commercially important fish species: whitefish and Eurasian perch. We compared simulation model outputs from two versions of an allometric trophic network model for Lake Constance, one with and one without the trout as the apex predator. The re-establishment of the declined brown trout reduced the perch population directly by predation and indirectly by increased…

Image analysis with environmental applications

2012

Kaukokartoitusmenetelmiä käytetään tarkkuusmaataloudessa ja metsien inventoinnissa. Pro gradu -tutkielma keskittyy parantamaan analysointiprosessia kasvillisuusmäärien arvioimiseksi esikäsitellyistä ilmakuvista ja digitaalisesta korkeusmallista. Tutkielmassa esitellään evolutiivinen optimointimenetelmä viljapellon biomassojen estimoimiseksi ja tutkitaan biomassaestimaattien tekoa eri menetelmin radiometrisesti korjatuista spektrikaistoista. Tutkielmassa pohditaan myös vaihtoehtoja puulajeittaisten tilavuuksien estimoimiseksi metsistä. Remote sensing methodologies are employed in the fields of precision agriculture and forest industry. This thesis focuses on enhancing analysation process for…

Three zone modeling of downdraft biomass gasification : equilibrium and finite kinetic approach

2013

Mathematical models and simulations are being practiced exceedingly in the field of research and development work. Simulations provide a less expensive means of evaluating the benefits and associated risk with applied field. Gasification is a complex mechanism, which incorporates thermochemical conversion of carbon based feedstock. Therefore, simulation of gasification provides a better comprehension of physical and chemical mechanism inside the gasifier than general conjecture and assist in optimizing the yield. The main objectives of present thesis work involve formulation of separate sub-model for pyrolysis and oxidation zone from published scientific references, and assembling it with p…