Assessing the impact of woody and agricultural biomass variability on its behaviour in torrefaction through Principal Component Analysis

The influence of biomass macromolecular composition on its behaviour in torrefaction was statistically assessed through Principal Component Analysis (PCA), both in terms of solid conversion kinetics and volatile species released, in function of the operating conditions. The experimental data obtained in the torrefaction of 14 woody and agricultural biomass samples at lab-scale was analysed. Main biomass macromolecular composition on cellulose, hemicelluloses and lignin was shown to acceptably represent biomass diversity, which can be complemented by the extractives and ash content. Similitudes were found in deciduous and coniferous wood families, respectively, while agricultural and herbaceous crops were shown as more heterogeneous, both in terms of characterization and behaviour in torrefaction. Cellulose, hemicelluloses and lignin content strongly influenced solid and volatile species yields in torrefaction, while biomass family exhibited a lower impact. Ash content in potassium, phosphorous and silicon did not show any influence on the extent of solid degradation through torrefaction. A lower variability was found in solid degradation profiles from woods, while agricultural crop behaviour was more heterogeneous. Different volatile species were released from biomass samples from the same family. Furthermore, different production profiles were found for volatile species chemically close, except for deciduous wood. These results indicate that, when modelling biomass torrefaction, solid mass loss can be represented by an exemplar of deciduous and coniferous wood, while several species would be required for the agricultural family. The variability of the volatile species release would require the consideration of several volatile species and several biomass samples per famil

THE IMPACT OF STORAGE CONDITIONS ON THE FOREST BIOMASS QUALITY FOR BIOFUELS PRODUCTION

Biomass quality is an essential parameter for the production of biofuels both by thermal ways (gasification, pyrolysis, torrefaction, etc) or biochemical ways (enzymatic hydrolysis and yeast saccharification). Storage is one of the most important parameters to be taken in account in the logistics chains of biomass supply for biofuel conversion sites. Morever, some benefits in terms of biomass quality can be obtained by storing biomass prior transportation or usage. In this case, storage can be considered as a pre-treatment of biomass for biofuel production. In this project, we have studied the evolution of biomass quality of different wooden resources (softwoods and hardwoods; short/very-short rotation coppices and residues of forest exploitation) stored under different conditions : seasons (spring/summer or autumn/winter), sites (forest roadside and storage platforms; uncovered and covered; under water sprinkling). Two locations were also tested, one in Bordeaux area (southwest of France) and the second in Dijon area (northeast of France). Different piles of approximately 10 m3 (2.5 to 3.5 tons of wood chips) were constituted for each modality. Samples were taken from two different levels of the piles at different intervals of storage (0 to 6 months). The following biomass quality parameters were followed : moisture content, elemental (C, H, O, N, S, Cl) and chemical (extractives, lignin, polysaccharides – cellulose and hemicelluloses, C5 and C6 sugars contents) composition; heating value; ash content, fusibility behaviour and composition. The results obtained indicated that the conditions of storage strongly influence the biomass quality, especially for the thermal conversion. The type of initial raw material (softwoods or hardwoods / short/very-short rotation coppices and residues of forest exploitation) are also of major importance, especially if the biomass material is stored with or without leaves. In that way, the season aspect becomes very important. Water sprinkling is an interesting way to remove certain compounds, such ash constituents or extractives, partially responsible for tar formation. On the other way, in this case a compulsory drying step is needed and a careful energy balance is needed in order to evaluate the pertinence or not of this technology. Concerning the biochemical conversion, no major differences were observed for the mono/polysaccharides contents. However, the removal of certain elements/substances could impact the enzymatic hydrolysis and fermentation for bioethanol production

Using macromolecular composition to predict optimal process settings in ring-die biomass pellet production

This study was performed to investigate if the process settings that give high pellet durability can be modelled from the biomass’ macromolecular composition. Process and chemical analysis data was obtained from a previous pilot-scale study of six biomass assortments that by Principal Component Analysis (PCA) was confirmed as representative for their biomass types: hardwood, softwood bark, short rotation coppice (SRC), and straw and energy crops. Orthogonal Partial Least Squares Projections to Latent Structures (OPLS) models were created with the content of macromolecules as factors and the die compression ratio and the feedstock moisture content at which the highest pellet durability was obtained as responses. The models for die compression ratio (R2X = 0.90 and Q2 = 0.58) and feedstock moisture content (R2X = 0.87 and Q2 = 0.60), rendered a prediction error for obtained mechanical durability of approximately ±1%-unit, each. Important factors for modelling of the die compression ratio were: soluble lignin (negative), acetyl groups (negative), acetone extractives (positive), and arabinan (positive). For modelling of the feedstock moisture content, Klason lignin (negative), xylan (positive), water-soluble extractives (negative), and mannan (negative), were the most influential. Results obtained in this study indicate that it is possible to predict optimal process conditions in pelletizing based on the macromolecular composition of the raw material. In practice, this would mean a higher raw material flexibility in the pellet factories through drastically reduced risk when introducing new raw materials

Pelleting torrefied biomass at pilot-scale – Quality and implications for co-firing

The co-firing of solid biofuels in coal plants is an attractive and fast-track means of cutting emissions but its potential is linked to biomass densification. For torrefied materials this topic is under-represented in literature. This pilot-scale (121–203 kg h−1) pelleting study generated detailed knowledge on the densification of torrefied biomass compared to untreated biomass. Four feedstock with high supply availability (beech, poplar, wheat straw and corn cob) were studied in their untreated and torrefied forms. Systematic methods were used to produce 180 batches of 8 mm dia. pellets using press channel length (PCL) and moisture content (MC) ranges of 30–60 mm and 7.3–16.6% (wet basis) respectively. Analysis showed that moderate degrees of torrefaction (250–280 °C, 20–75 min) strongly affected pelleting behaviour. The highest quality black pellets had a mechanical durability and bulk density range of 87.5–98.7% and 662–697 kg m−3 respectively. Pelleting energy using torrefied feedstock varied from −15 to +53 kWh t−1 from untreated with increases in production fines. Optimal pelleting MC and PCL were reduced significantly for torrefied feedstock and pellet quality was characterised by a decrease in mechanical durability and an increase in bulk density. Energy densities of 11.9–13.2 GJ m−3 (as received) were obtained

Understanding the torrefaction of woody and agricultural biomasses through their extracted macromolecular components. Part 2: Torrefaction model

A new torrefaction mode! was proposed for predicting solid mass loss in torrefaction as a function of biomass main macromolecular composition and type, as well as on the operating conditions. To do this, solid degradation kinetics were modelled following a 2-successive reaction scheme for each macro­compound and the additive modelling approach through biomass macromolecular component behavior in torrefaction proposed by Nocquet et al. (2014). The use of extracted fractions from different woody and agricultural biomass species (ash-wood, beech, miscanthus, pine and wheat straw) instead of commercial compounds increased the accuracy of the prediction of solid kinetics in biomass torrefaction. The validation of the proposed mode! with 9 raw biomasses in torrefaction showed an accurate pre­diction for woods, white the prediction for agricultural biomasses was acceptable

Molecular and phenotypic profiling from base to the crown in maritime pine wood-forming tissue

Research• Environmental, developmental and genetic factors affect variation in wood properties at the chemical, anatomical and physical levels. Here, the phenotypic variation observed along the tree stem was explored and the hypothesis tested that this variation could be the result of the differential expression of genes/proteins during wood formation. • Differentiating xylem samples of maritime pine (Pinus pinaster) were collected from the top (crown wood, CW) to the bottom (base wood, BW) of adult trees. These samples were characterized by Fourier transform infrared spectroscopy (FTIR) and analytical pyrolysis. Two main groups of samples, corresponding to CW and BW, could be distinguished from cell wall chemical composition. • A genomic approach, combining large-scale production of expressed sequence tags (ESTs), gene expression profiling and quantitative proteomics analysis, allowed identification of 262 unigenes (out of 3512) and 231 proteins (out of 1372 spots) that were differentially expressed along the stem. • A good relationship was found between functional categories from transcriptomic and proteomic data. A good fit between the molecular mechanisms involved in CW–BW formation and these two types of wood phenotypic differences was also observed. This work provides a list of candidate genes for wood properties that will be tested in forward genetic

Extremozymes for wood-based building blocks: from pulp mill to board and insulation products – WoodZymes project

4 páginas.- 4 referencias.- Comunicación oral presentada en el 16th European Workshop on Lignocellulosics and Pulp (EWLP) Gothenburg, Sweden, June 28 – July 1, 2022Enzymes can substitute harsh and energy-demanding chemical treatments for production of bio-based building blocks and products from wood processing. However, their properties need to be adapted to the extreme operation conditions (such as high T and pH) commonly used by these industries. Here, we summarize the main results obtained during the WoodZymes European Project (www.woodzymes.eu), which aimed to provide tailor-made extremozymes and extremozyme-based processes never assayed before in wood biorefineries. Novel extremophilic enzymes active on kraft lignin (laccases) and xylan (xylanases) were developed and produced at pilot or industrial scales. The enzymatic fractionation of kraft lignins using the METNINTM lignin refining technology, and the extremozyme-aided delignification and bleaching of kraft pulps were demonstrated at pilot scale. The resulting lignin and hemicellulose derived compounds were chemically characterized and applied as components of phenol-(lignin)-formaldehyde resins for wood panels and of polyurethane foams, or as papermaking additives. The new extremozymes were also applied to improve some of the latter applications. The techno-economic and environmental assessment of the new materials and processes, developed in WoodZymes project, showed that extremozyme-based processes led to clear benefits in energy savings during the refining of pulp or wood fibres, enabled lower addition of harsh chemicals (e.g. ClO2 during pulp bleaching), and resulted in a lower carbon footprint of the new bio-based products by substitution of fossil-derived components.WoodZymes project was funded by the Bio-based Industries Joint Undertaking (BBI JU) under GA 792070. The BBI JU received support from the EU’s H2020 research and innovation programme and the Bio Based Industries ConsortiumN

Sodium hydroxide diffusivity in thin wood chips interpreted by a capillary pore model: a study on twelve softwood and hardwood species

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