Catalytic Gasification and Reforming of Residual Biomass in a Bench Scale System with Low Cost Catalysts

This paper demonstrates the effectiveness of using of different catalysts for reforming tars contained in the syngas of biomass gasifiers. The conversion of the tar content allows to obtain high quality syngas and to maximize the gas fraction. A bench scale equipment consisting of an autothermal fluidized bed gasifier and a downstream packed bed reformer was used. Pine sawdust was selected as the feedstock for gasification. TGA analysis showed that the temperature must be above 350 °C to ensure the ignition of the biomass and maintain the process in an autothermal steady-state. Dolomite and pyrolysis char were used to test of the fluidized bed catalysts. In the reformer, dolomite, pyrolysis char, iron doped activated carbon and spent HDS catalyst were used. All catalysts decreased the CO2 concentration in the product gas and increased H2 , CH4 and CO. When iron doped activated carbon is used, tar contents below 60 g/Nm3 in the product gas could be obtained, reaching less than 1 g/Nm3 . The best value of LHV (lower heating value) was obtained with pyrolysis char as a catalyst (4.8 MJ/Nm3 ). The results demonstrate that catalytic biomass gasification with downstream tar reforming with low-cost catalysts is a promising solution for energy applications.

Chemocatalytic value addition of glucose without carbon-carbon bond cleavage/formation reactions: an overview

As the monomeric unit of the abundant biopolymer cellulose, glucose is considered a sustainable feedstock for producing carbon-based transportation fuels, chemicals, and polymers. The chemocatalytic value addition of glucose can be broadly classified into those involving C-C bond cleavage/formation reactions and those without. The C6 products obtained from glucose are particularly satisfying because their syntheses enjoy a 100% carbon economy. Although multiple derivatives of glucose retaining all six carbon atoms in their moiety are well-documented, they are somewhat dispersed in the literature and never delineated coherently from the perspective of their carbon skeleton. The glucose-derived chemical intermediates discussed in this review include polyols like sorbitol and sorbitan, diols like isosorbide, furanic compounds like 5-(hydroxymethyl)furfural, and carboxylic acids like gluconic acid. Recent advances in producing the intermediates mentioned above from glucose following chemocatalytic routes have been elaborated, and their derivative chemistry highlighted. This review aims to comprehensively understand the prospects and challenges associated with the catalytic synthesis of C6 molecules from glucose.

Corrosion Behavior of Zn, Fe and Fe-Zn Powder Materials Prepared via Uniaxial Compression

Powder metallurgy is one of the most prevalent ways for metallic degradable materials preparation. Knowledge of the properties of initial powders used during this procedure is therefore of great importance. Two different metals, iron and zinc, were selected and studied in this paper due to their promising properties in the field of biodegradable implants. Raw powders were studied using scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDX). Powders (Fe, Zn and Fe-Zn in a weight ratio of 1:1) were then compressed at the pressure of 545 MPa to the form of pellets with a diameter of 1.7 cm. Surface morphology and degradation behavior in the Hanks´ solution were studied and evaluated. Electrochemical polarization tests along with the static immersion tests carried out for 21 days were employed for corrosion behavior characterization. The highest corrosion rate was observed for pure Zn powder followed by the Fe-Zn and Fe, respectively. A mixed Fe-Zn sample showed similar properties as pure zinc with no signs of iron degradation after 21 days due to the effect of galvanic protection secured by the zinc acting as a sacrificial anode.

Nanoarchitectonics from Molecular Units to Living-Creature-Like Motifs

Important points for the fabrication of functional materials are the creation of nanoscale/molecular-scale units and architecting them into functional materials and systems. Recently, a new conceptual paradigm, nanoarchitectonics, has been proposed to combine nanotechnology and other methodologies including supramolecular chemistry, self-assembly and self-organization to satisfy major features of nanoscience and promote the creation of functional materials and systems. In this account article, our recent research results in materials development based on the nanoarchitectonics concept are summarized in two stories, (i) nanoarchitectonics from fullerenes as the simplest nano-units and (ii) dimension-dependent nanoarchitectonics from various structural units. The former demonstrates creativity of the nanoarchitectonics concept only with simple construction stuffs on materials fabrications, and a wide range of material applicability for the nanoarchitectonics strategy is realized in the latter ones.