During the past four years, the European wood pellet market is currently continuing to increase. Total European consumption was about 9.8 Tg and Italian market reaches almost 1 Tg mainly for domestic ...supply. The present investigation provides an evaluation of pellet quality of Italian market by analysis of 88 wood pellet samples acquired randomly and directly from the sale points. Particular attention has been dedicated to relationship between ash and some elements. Results highlight that only half of samples fulfil the A1 class (best quality) requirements established in the EN 14961-2. Statistical analysis pointed out that ash content is mainly linked to sulphur, potassium and chlorine. The results show that low limit threshold values for ash content ensure low chlorine and sulphur contents.
•Several pellet samples were collected directly in the market and analysed.•EN 14961-2 standard defines pellet quality.•Pellet quality is important for small domestic applications like boilers and stoves.•Only a half of the samples fulfil the better quality class requirements.•Ash content is mainly linked to sulphur, potassium and chlorine.
•The assessment of the quality of wood pellet sold in the market has been carried out.•The relationship between information reported on bag and pellet quality was evaluated.•More than half of samples ...fulfill EN 14961-2 A1 quality class requirements.•Certification is appropriated to guarantee for a high quality of pellet sold in the market.•Ash content alone is a representative parameter for a rapid assessment of pellet quality.
Wood pellet production has increased hugely in recent years from 7 to 19 milliontons in the period 2006–2012, mainly due to the demand created by policies and bioenergy use targets in Europe. Italy is one of the most important importers for domestic heating application and the Italian market can be considered a good subject to estimate the efficacy of quality standards and certification application. The assessment of the quality of wood pellet sold in the market and how the information reported on bag reflect the quality of the product has been carried out during a three-year period. Characterisation analyses and collection of data regarding information reported on bags such as characterisation results, ash class, wood species, certifications, and standard references have been carried out. Results have been statistically evaluated. More than half of samples fulfill the requirements of the A1 class of EN 14961-2 standard, related to the higher quality pellets. Certification, like ENplus and DINplus, appears to be appropriated to guarantee for a high quality of pellet sold in the market. Ash content alone could be a good representative parameter for a first, rapid quality assessment. Ash content results significantly lower in coniferous pellet than in broadleaf one.
•Torrefaction of tomato peels was studied.•Temperature results more significant than residence time.•Up to 30% of the mass was lost with an energy densification increment of about 20%.•Torrefaction ...produces high carbon content fuel-like material.•Results suggest the application of a mild torrefaction.
The standardization is an important aspect for fuel products. Some residual biomass are highly heterogeneous making their energy use rather difficult. Torrefaction can represent an interesting process to improve the standardization and quality of the lignocellulosic biomass. In the present research torrefaction has been applied on tomato peels, an important Italian industry residue. Different residence times and torrefaction temperatures have been employed in a bench top torrefaction reactor. Proximate, ultimate, thermogravimetric and infrared analyses of raw and torrefied material have been performed to evaluate the influence of the process. From the mildest condition studied to the most severe one, mass yield, energy yield and energy densification vary in the ranges of 94.7–69.9%, 98.0–86.0% and 1.04–1.23 respectively. According to mass and energy yields, ultimate analysis and thermogravimetric profiles, temperature parameter results more significant than residence time. Torrefaction makes the material increasingly hydrophobic as torrefaction temperature increases. This results in a more biologically stable and standardized material suitable to be employed as fuel for energy application. The results of this paper provide useful indications and suggest a mild torrefaction.
Vine is one of the most widespread crop cultivated in Italy. The management of these residues is linked to an additional cost for the operator and determines environmental issues mainly due to open ...field combustion. A better exploitation of these residues could be the use for thermal energy production in residential heating devices fuelled with pellet. In the present work vineyard pruning residues were collected, pelletised, then characterised according to the standard for solid biofuels. Combustion tests were performed in a 150 kWth boiler fuelled with pruning pellet and the related TSP, CO, NOx emissions were measured. In order to make a comparison with the open field combustion emissions of the vineyard pruning residues, simulation tests were conducted at lab scale. Open field emissions are up to 120 times for CO emission and 30 times for TSP more than the boiler emission. Results highlighted that by avoiding open field combustion and using this residual biomass for energy production, a significant reduction of environmental pollution together with an increase in renewable energy production can be obtained. The results can be useful as support for policy makers engaged in developing the strategy for the promotion of renewable energy and air quality improvement.
•Raw vineyard pruning residues and their pellet were characterised as solid biofuels.•Combustion tests with vineyard residues pellet were carried out on 150kWth boiler.•Open field combustion of vineyard residues were simulated at lab scale.•Open field combustion emits up to 120 times CO and 30 times TSP more than boiler.•In Italy open field vineyard pruning combustion can emit 137 kt CO and 13.7 kt TSP.
European policy promotes renewable energies and sets specific targets. Solid biofuels can play a significant role and the quality is an important aspect to be checked. Quality parameters such as ...origin and source are also required by specific biofuel standards. Therefore it could be useful to develop a rapid and cheap tool to distinguish between hardwoods and softwoods especially in unstructured, milled or densified wood in order to check the compliance of producer's declarations. Compared to other analytical methods, infrared spectroscopy is fast, non-destructive and low cost. In this study Fourier transform infrared (FTIR) spectroscopy coupled with Soft Independent Modelling of Class Analogy (SIMCA) has been evaluated as a method for discrimination purpose. A large dataset of 110 wood samples belonging to 12 species were analysed. In addition 4 blends were also analysed to test the discrimination performance of the tool. FTIR-SIMCA has correctly classified 93% of hardwood samples and 100% of softwood samples at high significance level. Furthermore, 100% of tested blends were associated with no class, showing a discrimination ability of the technique in recognizing blends from pure material. This method could be useful to verify the compliance of producer declarations about wood origin and source.
•Quality parameters such as origin and source are required by pellet standards.•The study aims to discriminate hardwoods and softwoods.•FTIR spectroscopy coupled with SIMCA has been evaluated as a suitable tool.•110 wood samples belonging to 12 species and 4 blends were analysed.•The method shows good performance and could be useful to verify standard compliance.
Considering the global warming and the climate change of the past few decades, European public policies have been established in order to increase the share of renewable energy sources. In the ...European context, one of the most interesting alternatives is woodchip. The present investigation provides an evaluation of woodchip quality underlining the relationships between the most important chemical and physical parameters, in particular between ash and some elements. Results highlight that the quality of woodchip is good even if some samples have very high ash content. Statistical analysis demonstrated that ash and moisture contents are highly linked to the net calorific value and a specific regression equation (R2 = 0.983) has been identified. Considering the chemical characteristics, statistical analyses pointed out the correlation between elements and ash content demonstrating that the quality classes of woodchip can be reasonably divided based on ash content.
•An evaluation of woodchip quality employed by power plants and CHP.•Ash and moisture contents variability is highly linked to net calorific value.•Ash content limits are in line with the chemical parameter limits (ISO 17225-4).•The quality classes of woodchip can be divided on the basis of ash.
Biomass is an important renewable energy source, in particular if obtained by residues it becomes even more sustainable. In Italy, residual biomass coming from olive oil industry, i.e. olive pomace, ...is produced in a significant amount and is concentrated in olive oil extraction sites, making interesting a possible valorisation of these residues. The different extraction processes employed influence the pomace quality and, consequently, it is fundamental to find a rapid technique to assess its physical and chemical characteristics for a correct valorisation. The aim of the work was to develop a NIR-based methodology to obtain in a fast and cheap way information about olive pomace. Several samples (n = 104) were collected in Marche region and analysed according to standards methods. NIR spectra were acquired using both fiberoptic probe and integrating sphere and subsequently were elaborated with multivariate techniques, i.e. principal component analysis (PCA) and partial least square regression (PLS). Results show that information on extraction process and composition of the pomace can be obtained. Prediction models with performance suitable for quality control applications were obtained for moisture and ash contents, whereas gross calorific value model was suitable only for screening application.
•Several samples of olive pomace from Marche region were collected and characterized.•NIR spectra were acquired for samples with fiberoptic probe and integrating sphere.•Multivariate models were developed to obtain qualitative and quantitative information.•Information on oil extraction process and composition of olive pomace were obtained.•Moisture content, gross calorific value and ash content can be carefully predicted.
MRI can assess plaque composition and has demonstrated an association between some atherosclerotic risk factors (RF) and markers of plaque vulnerability in naive patients. We aimed at investigating ...this association in medically treated asymptomatic patients. This is a cross-sectional interim analysis (August 2013-September 2016) of a single center prospective study on carotid plaque vulnerability (MAGNETIC study). We recruited patients with asymptomatic carotid atherosclerosis (US stenosis > 30%, ECST criteria), receiving medical treatments at a tertiary cardiac rehabilitation. Atherosclerotic burden and plaque composition were quantified with 3.0 T MRI. The association between baseline characteristics and extent of lipid-rich necrotic core (LRNC), fibrous cap (CAP) and intraplaque hemorrhage (IPH) was studied with multiple regression analysis. We enrolled 260 patients (198 male, 76%) with median age of 71-y (interquartile range: 65-76). Patients were on antiplatelet therapy, ACE-inhibitors/angiotensin receptor blockers and statins (196-229, 75-88%). Median LDL-cholesterol was 78 mg/dl (59-106), blood pressure 130/70 mmHg (111-140/65-80), glycosylated hemoglobin 46 mmol/mol (39-51) and BMI 25 kg/m
(23-28); moreover, 125 out of 187 (67%) patients were ex-smokers. Multivariate analysis of a data-set of 487 (94%) carotid arteries showed that a history of hypercholesterolemia, diabetes, hypertension or smoking did not correlate with LRNC, CAP or IPH. Conversely, maximum stenosis was the strongest independent predictor of LRNC, CAP and IPH (p < 0.001). MRI assessment of plaque composition in patients on treatment for asymptomatic carotid atherosclerosis shows no correlation between plaque vulnerability and the most well-controlled modifiable RF. Conversely, maximum stenosis exhibits a strong correlation with vulnerable features despite treatment.
Imaging the Surface of Altair Monnier, John D; Zhao, M; Pedretti, E ...
Science,
07/2007, Letnik:
317, Številka:
5836
Journal Article
Recenzirano
Odprti dostop
Spatially resolving the surfaces of nearby stars promises to advance our knowledge of stellar physics. Using optical long-baseline interferometry, we constructed a near-infrared image of the rapidly ...rotating hot star Altair with a resolution of <1 milliarcsecond. The image clearly reveals the strong effect of gravity darkening on the highly distorted stellar photosphere. Standard models for a uniformly rotating star cannot explain our findings, which appear to result from differential rotation, alternative gravity-darkening laws, or both.
PDF
