Biomass carbonization: process options and economics for small scale forestry farms

Bioenergy represents a unique opportunity for forestry companies to diversify the sources of income and create new stable business opportunities: a large number of initiatives has started in the last decades especially regarding decentralized power generation; nevertheless the conversion of the farmers to energy producers is not a trivial issue. The present work has focused on a possible alternative to biopower generation for forestry farms: the biomass carbonization (i.e. biomass slow pyrolysis). Charcoal making presents good prerequisite conditions for successful biomass based systems in the forestry sector: the system results incentive-independent, the power generation represents the co-product of a different primary production (resulting a real additional income), the plant capital cost is affordable for small scale farmers, operations requires technical skills normally available in the forestry sector and the reliability of the system is proven and credible, reducing the risks contained in business plans based on "number of hours of operation over several years". Moreover charcoal is a well known product, familiar to forestry companies for a very long time, the market is well defined, the technology is known but still offers opportunities for further improvements (in terms of efficiency, costs and environmental impacts), the technology does not present major risk, the investment is well suited to small farmers and the process and technology gives a great opportunity for small scale and local supply chain development. Based on these considerations, the present work investigated the technological opportunities for small scale charcoal making systems. Various process configurations have been examined, focusing on advantages and disadvantages representative of each solution in view of small scale application suitable for the Italian case and a designed pilot plant has been proposed

Integration of SRF and carbonization plant for small forestry farms

A continuous oxidative carbonization pilot unit, with a capacity of 50 kg/h,has been developed and builtby RE-CORD; reported performance data shows that the unit can produce high quality charcoal, suitable for BBQ, metallurgy of activated-carbon manufacturing, as well as biochar. Charcoal yield in excess of 24 wt% (dry) has been achieved, with a fixed carbon content higher than 85 wt% (dry). In this work,the up-scaled 250 kg/h demo plant has been designed, and the construction, operation and maintenancecosts estimated. It was assumed to feed the plant with a dedicated SRF of either poplar or robinia, which represents a very innovative and yet unexplored value chain. Performance data are reported along with economic evaluation of the whole chain. Results shows how aland management scheme based on SRF coupled to innovative small-scale biomass carbonization technology represents an appealing opportunity for business diversification in small and medium forestry enterprises

Aqueous phase reforming of the residual waters derived from lignin-rich hydrothermal liquefaction: investigation of representative organic compounds and actual biorefinery streams

Secondary streams in biorefineries need to be valorized to improve the economic and environmental sustainability of the plants. Representative model compounds of the water fraction from the hydrothermal liquefaction (HTL) of biomass were subjected to aqueous phase reforming (APR) to produce hydrogen. Carboxylic and bicarboxylic acids, hydroxyacids, alcohols, cycloketones and aromatics were identified as model compounds and tested for APR. The tests were performed with a Pt/C catalyst and the influence of the carbon concentration (0.3–1.8 wt. C%) was investigated. Typically, the increase of the concentration negatively affected the conversion of the feed toward gaseous products, without influencing the selectivity toward hydrogen production. A synthetic ternary mixture (glycolic acid, acetic acid, lactic acid) was subjected to APR to evaluate any differences in performance compared to the tests with single compounds. Indeed, glycolic acid reacted faster in the mixture than in the corresponding single compound test, while acetic acid remained almost unconverted. The influence of the reaction time, temperature and carbon concentration was also evaluated. Finally, residual water resulting from the HTL of a lignin-rich stream originating from an industrial-scale lignocellulosic ethanol process was tested for the first time, after a thorough characterization. In this framework, the stability of the catalyst was studied and found to be correlated to the presence of aromatics in the aqueous feedstock. For this reason, the influence of an extraction procedure for the selective removal of these compounds was explored, leading to an improvement in the APR performance

Epitaxial (111) Films of Cu, Ni, and CuxNi_xNi_yonα−Al on {\alpha}-Al_2OO_3$(0001) for Graphene Growth by Chemical Vapor Deposition

Films of (111)-textured Cu, Ni, and Cu$_x$Ni$_y$ were evaluated as substrates for chemical vapor deposition of graphene. A metal thickness of 400 nm to 700 nm was sputtered onto a substrate of $\alpha-$Al$_2$O$_3$(0001) at temperatures of 250 C to 650 C. The films were then annealed at 1000 C in a tube furnace. X-ray and electron backscatter diffraction measurements showed all films have (111) texture but have grains with in-plane orientations differing by $60^{\circ}$. The in-plane epitaxial relationship for all films was $[110]_{metal}$||$[10\bar{1}0]_{{Al}_{2}{O}_{3}}$. Reactive sputtering of Al in O$_2$ before metal deposition resulted in a single in-plane orientation over 97 % of the Ni film but had no significant effect on the Cu grain structure. Transmission electron microscopy showed a clean Ni/Al$_2$O$_3$ interface, confirmed the epitaxial relationship, and showed that formation of the $60^{\circ}$ twin grains was associated with features on the Al$_2$O$_3$ surface. Increasing total pressure and Cu vapor pressure during annealing decreased the roughness of Cu and and Cu$_x$Ni$_y$ films. Graphene grown on the Ni(111) films was more uniform than that grown on polycrystalline Ni/SiO$_2$ films, but still showed thickness variations on a much smaller length scale than the distance between grains

Behavior of molecules and molecular ions near a field emitter

The cold emission of particles from surfaces under intense electric fields is a process which underpins a variety of applications including atom probe tomography (APT), an analytical microscopy technique with near-atomic spatial resolution. Increasingly relying on fast laser pulsing to trigger the emission, APT experiments often incorporate the detection of molecular ions emitted from the specimen, in particular from covalently or ionically bonded materials. Notably, it has been proposed that neutral molecules can also be emitted during this process. However, this remains a contentious issue. To investigate the validity of this hypothesis, a careful review of the literature is combined with the development of new methods to treat experimental APT data, the modeling of ion trajectories, and the application of density-functional theory simulations to derive molecular ion energetics. It is shown that the direct thermal emission of neutral molecules is extremely unlikely. However, neutrals can still be formed in the course of an APT experiment by dissociation of metastable molecular ions

Computational Study of Hippocampal-Septal Theta Rhythm Changes Due to Beta-Amyloid-Altered Ionic Channels

Electroencephagraphy (EEG) of many dementia patients has been characterized by an increase in low frequency field potential oscillations. One of the characteristics of early stage Alzheimer’s disease (AD) is an increase in theta band power (4–7 Hz). However, the mechanism(s) underlying the changes in theta oscillations are still unclear. To address this issue, we investigate the theta band power changes associated with β-Amyloid (Aβ) peptide (one of the main markers of AD) using a computational model, and by mediating the toxicity of hippocampal pyramidal neurons. We use an established biophysical hippocampal CA1-medial septum network model to evaluate four ionic channels in pyramidal neurons, which were demonstrated to be affected by Aβ. They are the L-type Ca2+ channel, delayed rectifying K+ channel, A-type fast-inactivating K+ channel and large-conductance Ca2+-activated K+ channel. Our simulation results demonstrate that only the Aβ inhibited A-type fast-inactivating K+ channel can induce an increase in hippocampo-septal theta band power, while the other channels do not affect theta rhythm. We further deduce that this increased theta band power is due to enhanced synchrony of the pyramidal neurons. Our research may elucidate potential biomarkers and therapeutics for AD. Further investigation will be helpful for better understanding of AD-induced theta rhythm abnormalities and associated cognitive deficits