Poplar Chips Research Articles

A high-efficiency solar desalination biomass material prepared by DBD plasma

Biomass materials for interfacial evaporation with solar energy have obvious advantages and potentials in the field of desalination. In this work, plasma technology is first used to prepare biomass materials for seawater desalination. The plasma carbonized film (PCF) is obtained from poplar chips treated by dielectric barrier discharge (DBD) plasma. The whole preparation process can be quickly achieved in one step without any chemical reagent or carrier gas. After DBD treatment, the original water channels of the xylem are preserved ensuring efficient water transport and high salt resistance. The hydrophobic nature of the evaporator surface makes it self-floating. Under sunlight irradiation, photons are captured by the black PCF surface converting solar energy into heat energy, and fresh water can be continuously and stably obtained from salt water. The evaporation rate under one sunlight by PCF in water and 3.5 wt% NaCl solution can reach 1.70 kg m−2 h−1, and 1.63 kg m−2 h−1, respectively. PCF has abundant micron-sized holes and low-distortion channels making the material form a 3D interconnection structure. Therefore, PCF has a solar-steam conversion efficiency as high as 91%. Besides, the tolerance test shows that PCF can still maintain a high evaporation rate and self-clean after long-term work.

Prospects of thermotolerant Kluyveromyces marxianus for high solids ethanol fermentation of lignocellulosic biomass

Simultaneous saccharification and fermentation (SSF) is effective for minimizing sugar inhibition during high solids fermentation of biomass solids to ethanol. However, fungal enzymes used during SSF are optimal between 50 and 60 °C, whereas most fermentative yeast, such as Saccharomyces cerevisiae, do not tolerate temperatures above 37 °C. Kluyveromyces marxianus variant CBS 6556 is a thermotolerant eukaryote that thrives at 43 °C, thus potentially serving as a promising new host for SSF operation in biorefineries. Here, we attempt to leverage the thermotolerance of the strain to demonstrate the application of CBS 6556 in a high solids (up to 20 wt% insoluble solid loading) SSF configuration to understand its capabilities and limitations as compared to a proven SSF strain, S. cerevisiae D5A. For this study, we first pretreated hardwood poplar chips using Co-Solvent Enhanced Lignocellulosic Fractionation (CELF) to remove lignin and hemicellulose and to produce cellulose-enriched pretreated solids for SSF. Our results demonstrate that although CBS 6556 could not directly outperform D5A, it demonstrated similar tolerance to high gravity sugar solutions, superior growth rates at higher temperatures and higher early stage ethanol productivity. We discovered that CBS 6556’s membrane was particularly sensitive to higher ethanol concentrations causing it to suffer earlier fermentation arrest than D5A. Cross-examination of metabolite data between CBS 6556 and D5A and cell surface imaging suggests that the combined stresses of high ethanol concentrations and temperature to CBS 6556’s cell membrane was a primary factor limiting its ethanol productivity. Hence, we believe K. marxianus to be an excellent host for future genetic engineering efforts to improve membrane robustness especially at high temperatures in order to achieve higher ethanol productivity and titers, serving as a viable alternative to D5A.

Comparison of Soda, Kraft, and DES Pulp Properties of European Black Poplar

Kraft pulping as the dominant pulping method contributes to several environmental problems. To overcome these problems, environmentally friendly pulping methods have been investigated. In the last years, deep eutectic solvents (DESs) have been identified as up-and-coming reagents in the lignocellulosic material processing and they are characterized as environmentally friendly. This study investigated the use of DES in pulp production from European black poplar chips. The DES mixture was prepared from choline chloride (ChCl) and ethylene glycol (EG). In addition, traditional soda and kraft pulping methods were carried out with poplar chips for comparison with the DES pulps. It was found that pulp production from poplar chips using DES was comparable to the soda and kraft pulps in terms of pulp yield, pulp viscosity, and opacity. The DES pulps easily reached target pulp freeness levels. However, the strength properties and brightness of the DES pulps were lower than those of the soda and kraft pulps. The strength properties of DES pulps can be improved with paper strength enhancers such as starch and micro or nanofibrillated cellulose. Also, the utilization of DES in pulp production may have an important role in cleaner production and it represents a greener alternative to traditional pulp production methods.

Supercritical production of extract from poplar containing bioactive substances – An economic analysis

The concept of a biorefinery entails, the multi-product use of biomass, which is processed to high quality products and afterwards the production residues are used for energy or other purposes. The maximum utilization of resources and the minimum impact on the natural environment are the two essential arguments attesting to the validity of this concept. Beside the environmental considerations, another important factor is the profitability of a production process, which underlies the market competitiveness of products. The main objective of the study presented in this article has been to analyse the life cycle costs and profitability of a chosen chain of values of two bioproducts: extract from poplar biomass and pellet from post-extraction residues, processed according to the concept of a biorefinery. The input raw material was biomass of poplar (Populus nigra × Populus maximowiczii (L.) Henry) grown in short rotations. The main bioproduct was dry extract, while post-extraction biomass was used to produce an energy co-product, which was pellet. The main bioproduct, generated by supercritical extraction, is an innovative ingredient of high-quality bioproducts, e.g. in veterinary medicine or in anti-inflammatory drugs. In this study, production costs in a chain of values composed of dry extract and pellet from poplar biomass were determined. The analysis included the determination of capital expenditures (CAPEX) and operating expenditures (OPEX) as well as life cycle costs (LCC). In addition, a production profitability analysis was made, where the profitability thresholds for production of dry extract and pellet were calculated, and the following investment profitability indicators were determined: net present value (NPV), internal rate of return (IRR), profitability index (PI) and discounted payback period (DPBP). The scope of analyses comprised the following system sets: subsystem I including expenditures and income related to the production of poplar chips in an annual cycle; subsystem II contained costs of transport to a drying plant, costs of drying and grinding as well as costs of transport to the next subsystem; subsystem III, known as a biorefinery, comprised expenditures and income related to the production of extract as well as costs and income related to the production of pellet. The highest capital expenditures (CAPEX) were incurred by the purchase (73%) and installation (22%) of a plant for supercritical extraction. In turn, the highest operating expenditures (OPEX) consisted of labor costs (59%) and costs of raw materials and utilities for the supercritical extraction process (37%). Production of extract and pellet was profitable.

Fractionation of Poplar Wood Using a Bifunctional Aromatic Acid under Mild Conditions

The development of an energy-efficient fractionation process as well as the preservation of the fractionated cellulose, hemicellulose sugars, and lignin are the key to the valorization of lignocellulose. This study presents a mild-condition fractionation process based on a recyclable and bifunctional 4-chlorobenzenesulfonic acid (4-Cl-BSA). The aqueous (e.g., 72%) 4-Cl-BSA solution near-completely fractionated unmilled poplar chips at 50–80 °C for 18–180 min and successively preserved the theoretical maximum yields and key structures of the fractionated cellulose, lignin, and hemicellulose sugars. Around 21.3–27.8% lignin was hydrotropically dissolved at a mesoscale level through accumulation by and complexation with 4-Cl-BSA and its aggregates. The solubilized lignin preserved about 24.7–50.7% of the 61% β-O-4 linkages in the native lignin and about 48.3–82% aromatic units uncondensed. About 72.2–78.7% lignin was insolubilized and quickly deposited on the surfaces of cellulose fibers. Remarkably, the deposited lignin preserved about 61.9–81.1% of the β-O-4 linkages in the native lignin and about 78.2–86.2% aromatic units uncondensed. Hemicellulose sugars and cellulose (millimeter-size, CrI: 71–75, DPᵥ: 910–1022) had high purity and high quality. Compared to the other selected aryl sulfonic acids whether they have or do not have substituents (dichloro, bromo, hydroxyl, and methyl) and mineral acids, 4-Cl-BSA performed better in fractionating unmilled poplar chips and preserving the β-O-4 linkages and aromatic units of lignin. The results indicate that both acidity and hydrophobicity of aryl sulfonic acid greatly influence its fractionation and preservation performances.

Energy producing effectiveness study: larch and poplar chips, wood pellets

Larch is one of the most valuable species of conifers. Its wood is widely used in many sectors of the economy. Therefore, determining the efficiency of energy use of by-products of processing of larch, as well as fast-growing wood species, which include poplar, is an important task. A study of the operational efficiency of the Firematic 60 boiler when working on larch and poplar chips, as well as spruce wood pellets with a diameter 6 mm was carried out. The elemental composition of burned fuels and residues was studied using an EDX-8000 X-ray fluorescence spectrometer and a Euro EA-3000 analyzer. The components of the heat balance and emission of harmful substances were determined. The emissions of particulate matter and the content of soot particles were studied. The shape and composition of soot particles were determined using a Zeiss SIGMA VP electronic scanning microscope. The energy tests showed that the boiler provides high technical and economic indicators and minimal emissions of harmful substances into the environment when burning larch and poplar chips, wood pellets.

Cold air ventilation for cooling and drying of poplar wood chips from short rotation coppice in outdoor storage piles in Germany

The storage and natural drying of wood chips from short rotation coppices (SRC) in open-air piles can be related to high dry matter losses (DML) of more than 20%. Thus it should be researched, whether such loss can energy efficiently be reduced using cold air ventilation (CAV). Respectively, a dedicated channel system for sensor controlled ventilation and drying of wood chips was developed and tested in the drying process of two storage piles of poplar chips (2 × 90 m³). The ventilation of the storage piles was facilitated in two consecutive program phases: a cooling program, subsequent to the harvest in the month of March, and a drying program under more favorable weather conditions in the month of April. The characteristically high temperature rise typical for wood chip storage immediately subsequent to storage intake could be limited to an average storage pile temperature of 6.3 °C with just 41 blower operation hours due to the cooling program in the month of March. Due to the subsequent drying process in April, the storage pile could be dried further from 51.5% to 11.9% in 196 blower operation hours. The required energy input for the process of CAV, consisting of cooling and drying, amounted to 456 MJ t−1 (dry matter). At a total demand of electric energy of 5332 MJ per storage pile, a more than six times higher thermal energy advantage of 35,233 MJ was achieved. DML of 11% were measured at the end of wood chip drying using CAV.

The yield and quality of Pleurotus abieticola grown on nematode-infected Pinus massoniana chips.

In this study, we investigated the use of nematode-infected Pinus massoniana chips (NPC) as the main ingredient in Pleurotus abieticola substrate. The effects of different substrate formulas on nutritional parameters, including total sugars, polysaccharides, proteins, lipids, amino acids, and fatty acids were assessed. The results indicated that NPC was suitable for P. abieticola cultivation. However, the addition of certain amounts of corncobs (CC) and cottonseed hulks (CH) improved the yield. Substrate T5 (45% NPC, 6% CC, and 27% CH) had the greatest yield (121.38 g per bag), 34.56% greater than the yield of the control (78% poplar chips), which was 79.43 g per bag. Across the 11 substrate formulas tested, the total sugar, polysaccharide, crude protein, and crude lipid contents were 16.60–28.90%, 2.71–3.73%, 36.49–45.42%, and 1.03–4.34%, respectively. On all substrates, the fruiting bodies contained 17 amino acids, primarily glutamine (2.42–4.11%), followed by proline (2.56–3.73%), leucine (2.09–3.19%), phenylalanine (1.56–2.61%), and glycine (1.76–2.55%). The fruiting bodies contained 12 fatty acids, of which linoleic acid was the most abundant (82.36%–84.03%), followed by palmitic acid (6.42%–6.89%) and oleic acid (5.50%–7.34%). The fatty acid content was closely associated with the NPC content, which might indicate that NPC promoted fatty acid accumulation. Thus, NPC represents a new substrate suitable for P. abieticola cultivation.

Study of the energy efficiency of wood pellets and poplar chips

Poplar is the most common type of fast-growing tree species of great economic and industrial importance. Therefore, determining the effectiveness of its energy use is an important task. A study of the operational efficiency of the Firematic 60 boiler when working on poplar chips, as well as pine wood pellets with a diameter of 6 mm and spruce wood pellets with a diameter of 8 mm was carried out. The elemental composition of burned fuels and residues was studied using an EDX-8000 X-ray fluorescence spectrometer and a Euro EA-3000 analyzer. The components of the heat balance and emission of harmful substances were determined. The emissions of particulate matter and the content of soot particles were studied. The shape and composition of soot particles were determined using a Zeiss SIGMA VP electronic scanning microscope. An energy examination showed that the boiler provides high technical and economic indicators and minimal emissions of harmful substances into the environment when burning wood pellets and poplar chips.

Environmental external cost of poplar wood chips sustainable production

Abstract In sustainable production, information about product costs should be complete. Not only economic but also environmental aspects need to be taken into consideration. The aim of this study was to estimate environmental external costs of poplar short rotation woody crops (SRWC) cultivation according to different soil enrichment procedures for wood chips production. The base scenario was to grow unfertilized crops. Three other scenarios were analyzed: mineral fertilization, lignin application, and combined lignin and mineral fertilization. The assessment of the environmental costs was based on emissions originating from production of poplar wood chips. The costs were calculated based on the emissions and their monetary value. The environmental external cost of the production of poplar chips was €137.24 ha−1 year−1 on average, and corresponded to 27.5% of the internal cost. The external cost of poplar chips production relative to a mass unit was €15.67 Mg−1 d.m. on average, corresponding to 20% of the total production cost. Our analysis shows that field emission and harvest generate most of the external cost. The highest cost was associated with particulate matter formation and terrestrial acidification.

Combination of xylanase and cellulase hydrolysis for enhanced saccharification of poplar chips: Process optimization

Removing xylan from the outer surface of cellulose could promote the accessibility of cellulase to cellulose. Under this premise, in order to develop an efficient pretreatment method to obtain fermentable reducing sugar from poplar fiber, a response surface methodology was created via the combination of the Plackett-Burman design and the Box-Behnken design and was utilized by the Design-Expert software. The optimum conditions were as follows: a liquid-solid ratio of 4.95 to 1 (mL/g), a pre-hydrolysis xylanase temperature of 70.3 °C, and a total hydrolysis time of cellulase of 52.9 h. Under these conditions, the maximum amount of reducing sugars converted from poplar fiber was 159.6 mg/g. The average amount from the validation results was 160.1 mg/g, which was in agreement with the predicted value. Meanwhile, the poplar fiber hydrolyzed via a xylanase-aided two-stage pretreatment was compared with the poplar fiber hydrolyzed via only a cellulase pretreatment, using scanning electron microscopy. The xylanase-aided treatment revealed a surface with a more damaged structure, indicating that the utilization of xylanase could further improve the effects of hydrolysis on poplar fibers.

Assessment on temperature-pressure severally controlled explosion pretreatment of poplar

In this work, temperature-pressure severally controlled explosion pretreatment (TPE) was proposed to pretreat poplar chips to improve the cellulase hydrolysis yield. In TPE process, native poplar chips (NP) were mixed with steam and N2 under pressure of 2.6, 2.8 and 3.0 MPa at 209 °C for 7 min. Meanwhile, steam explosion (SE) was also used to pretreat poplar chips for comparison at 209 °C (1.9 MPa) for 7 min. Results showed that the contents of hemicellulose and lignin were decreased from 19.4 % to 4.6 % and from 27.8 %–19.5 % with increasing pressure, respectively. For cellulase hydrolysis process, TPE was more advantageous than SE due to lower contents of hemicellulose and lignin, resulting in a higher cellulose conversion (40.7 %) in relation to SE sample (34.9 %). The Langmuir isothermal- type equation expressed the factors related to the hydrolysis capacity, and the results showed that this model can well describe the kinetics of the enzymatic hydrolysis.

Removal of ammonium and phosphate from water by Mg-modified biochar: Influence of Mg pretreatment and pyrolysis temperature

Poplar chips before and after a magnesium (Mg) pretreatment were pyrolyzed under different temperatures to obtain pristine and Mg-modified biochar samples (i.e., 300/BC, 450/BC, 600/BC, 300Mg/BC, 450Mg/BC, and 600Mg/BC). The biochars were used to evaluate how pyrolysis temperature and Mg modification influenced their capacity to adsorb ammonium and phosphate from eutrophic waters. An increased temperature caused an increase in carbonization degree, a more developed porous structure, and a decrease in the functional groups on biochar. The Mg modification was helpful for the development of a porous structure and the preservation of functional groups. The optimal ammonium adsorption was obtained by 300Mg/BC. This was attributed to the enriched functional groups. The maximum adsorption capacity was 58.6 mg/g. The 600Mg/BC sample exhibited optimal adsorption for phosphate with a maximum adsorption capacity of 89.0 mg/g, which was ascribed to the large surface area, the positively charged surface, and the metal oxides effect. A pseudo-second-order kinetic model and Langmuir–Freundlich isothermal model well described the adsorption of ammonium and phosphate on the modified biochar.

Pretreatment and enzymatic hydrolysis for the efficient production of glucose and furfural from wheat straw, pine and poplar chips

A flexible approach to a two-step Biorefinery for the production of glucose and furfural from three different feedstocks is presented. Pretreatment conditions were selected to drive the production towards the generation of glucose or furfural. Harsh pretreatment conditions produced solids with highly accessible glycan contents for the enzymatic hydrolysis with 100% glucose yields when wheat straw or poplar chips were used as feedstock. Mild conditions afforded xylan-rich hydrolysates that could be efficiently transformed to furfural, either under conventional or microwave heating in biphasic media. Yields for the transformation of xylan from feedstocks ranged between 45% and 90% depending on the feedstock, the thermal pretreatment and the cyclodehydration conditions. Up to 12.6 kg of glucose and materials and 2.5 kg of furfural can be produced starting from 50 kg of biomass. A new analytical methodology based on 13C NMR that provided good quality analytical results is also presented.

Overhead Protection Increases Fuel Quality and Natural Drying of Leaf-On Woody Biomass Storage Piles

Short-rotation woody crops (SRWC) have the potential to make substantial contributions to the supply of biomass feedstock for the production of biofuels and bioproducts. This study evaluated changes in the fuel quality (moisture, ash, and heating value) of stored spring harvested shrub willow (Salix spp.) and hybrid poplar (Populus spp.) chips with respect to pile protection treatments, location within the storage piles, and length of storage. Leaf-on willow and poplar were harvested in the spring, and wood chips and foliage with moisture content in the range of 42.1% to 49.9% (w.b.) were stored in piles for five months, from May to October 2016. Three protection treatments were randomly assigned to the piles. The control treatment had no cover (NC), so piles were exposed to direct solar radiation and rainfall. The second treatment had a canopy (C) installed above the piles to limit direct rainfall. The final treatment had a canopy plus a dome aeration system (CD) installed over the piles. Covering piles reduced and maintained the low moisture content in wood chip piles. Within 30 days of establishment, the moisture content in the core of the C pile decreased to less than 30%, and was maintained between 24%–26% until the end of the storage period. Conversely, the moisture content in the NC piles decreased in the first two months, but then increased to the original moisture content in the core (>45 cm deep) and up to 70% of the original moisture content in the shell (<45 cm deep). For all the treatments in the tested conditions, the core material dried faster than the shell material. The higher heating value (HHV) across all the treatments increased slightly from 18.31 ± 0.06 MJ/kg at harvest to 18.76 ± 0.21 MJ/kg at the end of the storage period. The lower heating value (LHV) increased by about 50% in the C and CD piles by the end of the storage period. However, in the NC piles, the LHV decreased by 3% in the core and 52% in the shell. Leaf-on SRWC biomass stored in piles created in late spring under climatic conditions in central and northern New York showed differing moisture contents when stored for over 60–90 days. Overhead protection could be used to preserve or improve the fuel quality in terms of the moisture content and heating value if more than two months of storage are required. However, the implementation of such management practice will depend on whether the end users are willing to pay a higher price for dryer biomass and biomass with a higher LHV.

Influence of the chip format on the development of mass loss, moisture content and chemical composition of poplar chips during storage and drying in open-air piles

In order to use wood chips from short-rotation coppices cost-efficiently, it is necessary to optimise the storage process depending on the planned use of the chips. The goal of all storage is to ensure low dry matter losses. Wood chips intended for energy-related use should have low moisture and ash contents, as well as a low fines fraction. If wood chips are to be put to material use, e.g. as peat substitute, a reduction of the C:N ratio during storage is necessary.The objective of this study was to identify favourable storage conditions to ensure low dry matter losses and high quality of wood chips for energy-related use. Furthermore, the study aimed to examine, whether disintegration processes during storage change the C:N ratio to such an extent that wood chips can be used as raw material for plant substrates.Three wood chip piles with different chip formats (small, medium, large - produced with a forage harvester and a mower chipper) were stored for seven months and compared regarding storage properties and physicochemical parameters.After seven months, medium wood chips displayed with a moisture content of 26w-%, dry matter losses of only 17% and a fines fraction of <5w-% the best results for energy-related use. Small chips with dry matter losses of 19%, moisture contents of 34w-% and a fines fraction of 12.6w-% displayed very unfavourable conditions for energy-related use. However, small chips showed the highest reduction of the C:N ratio (from 145:1 to 57:1) due to the storage process.

Exploring the influence of initial liquor pH in the pre-hydrolysis stage on alpha-cellulose production from poplar

The effect of using auto pre-hydrolysis liquor, acidic pre-hydrolysis liquor, and alkaline pre-hydrolysis liquor on the production of alpha cellulose from poplar was investigated across this research work. Poplar chips were pulped with soda-AQ pulping process at a kappa number of 15 after being pre-hydrolyzed with different pre-hydrolysis liquors at 170 °C. The residual lignin of chips were more delignified by about 40% using a single stage oxygen delignification and totally bleached with a D0ED1 bleaching sequence. The results indicated that the yield and kappa number of the pulps can be affected by the kind of pre-hydrolysis liquor. In general, using acidic and alkaline catalysts in pre-hydrolysis liquor led to an acceleration in the rate of hemicellulose separation and kappa number reduction. The alkaline pre-hydrolysis and auto pre-hydrolysis had the highest and the least efficiency to remove hemicelluloses from the wood and purify the produced alpha cellulose, respectively. The alkaline pre-hydrolyzed dissolving pulp of poplar due to existing alkali catalyst in the pre-hydrolysis liquor and occurring alkaline darkening had the least brightness, while the acidic pre-hydrolyzed dissolving pulp, because of the effect of acidic catalyst on the reduction of chromophore compounds, had the highest brightness among the pulps. The results illustrated that a dissolving pulp with more purity and alpha-cellulose content is achievable from Poplar through employing an alkaline pre-hydrolysis stage, soda-AQ pulping, and OD0ED1 bleaching sequence.

Briquettes Properties after Four Years Storage

. The paper presents the results of laboratory tests intent on the study of storage place, placing manner and storage time on mechanical properties of briquettes made from poplar chips. For the briquettes production the briquetting press of the firm Briklis was used, type BrikStar 30-12, of 50 mm pressure chamber diameter. All briquettes were made at the briquetting press all parameters constant adjustment. The briquettes properties were evaluated by their density and rupture force determination. Moreover the mechanical durability, the gross calorific value, the total moisture and the ash content were determined. By the carried out tests it was univocally proved that the mode of storage influences briquettes durability at their long-term storage most of all Briquettes, deposited in the well closed plastic bag in closed heated room, changed their properties during four years only minimally. Briquettes, deposited in the same place but in plastic net bag, changed their properties much more. Briquettes, deposited in the well closed plastic bag in closed unheated room, changed their properties during four years only minimally. Briquettes, deposited in plastic net bag, changed their properties to such a degree that they were practically unusable. On the basis of the carried out tests it is possible to state that for the parameter of briquettes quality evaluation the rupture force can be recommended.

Long term storage of poplar chips in Mediterranean environment

Industrial poplar plantations reach maturity in about 10–15 years, showing a wood productivity that is hardly achieved by other broadleaf species. Among the possible uses of this product, the energetic production is one of the most promising as it can offer additional revenues to plantation owners. However, the difficult handling and the large volumes occupied by crowns during storage decrease significantly the convenience of the recovery. Therefore, efficient and affordable storage methods need to be identified in order to make this product more manageable and profitable. The main goal of the research is to understand the dynamic of a long-term storage lasting 18 months and the effects of storage on fuel quality in both stem and crown of poplar chips. Storage performance were evaluated with respect to moisture content, dry matter losses, particle size distribution, bulk density, and fuel quality before and after storage. Contrary to the results obtained in Northern climates, this study revealed the poor storability of poplar chips, regardless the plant component (bole, branch, crown) considered, showing in the worse cases dry matter losses higher close to 50% and final moisture mass fraction increases to about 70%.

Pre-extraction of Hemicelluloses from Poplar Chips and its Effect on Kraft Pulping

Pre-extraction of Hemicelluloses from Poplar Chips and its Effect on Kraft Pulping