Birch Wood Chips Research Articles

Synthesis of nitrogen-doped carbon catalyst from hydrothermally carbonized wood chips for oxygen reduction

An efficient carbon material was prepared using hydrothermal carbonization of birch-wood chips in the water under elevated pressure, subsequent chemical activation, and doping with nitrogen. The obtained catalyst had a large specific surface area of 2431 m2 g−1 and a high nitrogen content of 4.60 at.%. Most of the nitrogen was in the pyridinic-N (57.61 at.%) form. The synthesized material exhibits excellent electro-catalytic activity for the oxygen reduction reaction with an onset potential of 0.9 V versus the reversible hydrogen electrode, showing the 4e− electrons transfer path in 0.1 M KOH solution.

Kraft cooking of birch wood chips: differences between the dissolved organic material in pore and bulk liquor

Abstract The delignification of birch chips during kraft pulping was investigated, targeting both the impregnation and cooking steps. Wood chips were impregnated using white liquor, white liquor + NaCl, water or NaCl aqueous solution. Then, the chips were cooked in batch autoclaves applying the same constant composition cooking conditions for all samples. Pulp and two fractions of black liquor (bulk liquor and centrifuged liquor representing the liquor inside the wood chips and fibers) were collected after different pulping times and analyzed for lignin and carbohydrate content. The dissolved wood components were precipitated from selected samples and characterized with respect to composition, molecular weight distribution and structural motifs. Cooking chemicals in the impregnation liquors led to faster delignification and xylan removal during cooking. Higher contents of lignin and xylan were measured in the lumen than in the bulk. The concentration profiles also showed accumulation of dissolved material in the lumen over time, suggesting significant mass transport limitation from lumen to bulk. Further analysis revealed higher fragmentation/degradation of dissolved material with increasing pulping time and in the bulk when compared to the lumen liquor, as demonstrated by the lower molecular weights and the changes in chemical shifts in the NMR spectra.

The retention of nitrogen and phosphorus in aboveground biomass of plants growing in constructed wetlands treating agricultural drainage

Three horizontal subsurface flow constructed wetlands (CW1, CW2 and CW3) for treatment of agricultural tile drainage water were built in 2018. Two wetlands were filled with a mixture of washed gravel and birch woodchips (10:1 volume ratio), in the third one the layer of woodchips was on top of a gravel layer. All wetlands were planted with Gyceria maxima and Phalaris arundinacea in parallel bands and parallel to water flow. Four-year study (2019–2022) was aimed at the amount of nutrients retained in aboveground plant biomass. The results revealed that the biomass of both species was lower as compared to biomass of these species growing in constructed wetlands for municipal sewage. Due to low aboveground macrophyte biomass, the nitrogen and phosphorus standing stocks were low (maximum 1.3 g P m−2 and 11.1 g N m−2). When comparing the nitrogen standing stocks with the inflow annual loadings and removed load, it represented on average only 2.38% of the removed load and 0.85% of the inflow load because of very high inflow loading (1298, 866 and 842 g N m−2 yr−1 in CW1, CW2 and CW3, respectively). On the other hand, the respective values for phosphorus amounted to 43.9% and 21.6% due to very low inflow loading (8.8, 6.6 and 6.0 g P m−2 yr−1 in CW1, CW2 and CW3, respectively). The study confirmed that plant contribution to nutrient removal in constructed wetlands expressed as removal percentage is strongly affected by inflow loading. The study also revealed that under low load conditions the plant uptake may substantially contribute to nutrient removal.

Hydrothermal Carbonization vs. Pyrolysis: Effect on the Porosity of the Activated Carbon Materials

Porous carbon materials (specific area over 2400 m2 g−1) were obtained from birch wood chips, the waste of its thermochemical processing water-insoluble lignocellulosic pyrolysis tar, and their mixture, by thermochemical activation with NaOH at 800 °C. Raw materials were carbonized by two methods: pyrolysis (500 °C) and hydrothermal (250 °C) treatment. The elemental and chemical composition of precursors and the effect of these parameters on the obtained carbon materials’ structure and porosity were studied. Results of the study showed that the carbonization method has little effect on the activated carbons’ specific surface area values; however, it allows for the regulation of pore size distribution.

Study of a Novel Biorefining Method for Obtaining 2-Furaldehyde, Acetic Acid and Pulp from Birch Wood

Necessity for reduction of greenhouse gases emissions, the growing demand for improvement of biorefinery technologies and the development of new biorefining concepts, oblige us as a society, mainly scientists, to develop novel biorefinery approaches. The aim of this research was to comprehensively characterize lignocellulosic biomass that was obtained after 2-furaldehyde production, in terms of further valorization of this resource. This research shows that birch wood chips can be used in the new biorefinery processing chain for production of 2-furaldehyde, acetic acid and subsequent cellulose pulp obtaining, using thermomechanical and alkaline peroxide mechanical pulping process. In addition, obtained lignocellulosic residue was also characterized. Unique bench-scale reactor system was used to obtain a lignocellulosic material without pentoses and with maximum preservation of cellulose fiber for further use. Studies on the deacetylation and dehydration of birch wood hemicelluloses of pentose monosaccharides to 2-furaldehyde and acetic acid using orthophosphoric acid as a catalyst were carried out. Results showed that depending on the used pretreatment conditions the 2-furaldehyde yield was from 0.04 to 10.84 % o.d.m., the acetic acid yield was from 0.51 to 6.50 % o.d.m. and the lignocellulose residue yield was from 68.13 to 98.07 % o.d.m. with minimal content of admixtures. In addition, experimentally the optimal 2-furaldehyde production conditions regarding to purity and usability of cellulose in leftover of lignocellulosic material were developed. Best results in terms of both 2-furaldehyde yield and purity of residual lignocellulose were obtained in experiment where catalyst concentration was 70%, catalyst amount 4 wt.%, reaction temperature 175 °C and treatment time 60 min. By performing alkaline peroxide mechanical pulping of the relevant LC residue, it was possible to obtain pulp with tensile index comparable to standard printing paper, indicating that it is possible to perform stepwise 2-furaldehyde production with subsequent pulping to obtain various value added products.

Thermomechanical and Alkaline Peroxide Mechanical Pulping of Lignocellulose Residue Obtained from the 2-Furaldehyde Production Process.

The necessity for the reduction in greenhouse gas emissions, the growing demand for the improvement of biorefinery technologies, and the development of new biorefining concepts oblige us as a society, and particularly us, as scientists, to develop novel biorefinery approaches. The purpose of this study is to thoroughly evaluate the leftover lignocellulosic (LC) biomass obtained after the manufacture of 2-furaldehyde, with the intention of further valorizing this resource. This study demonstrates that by using thermomechanical and alkaline peroxide mechanical pulping techniques, birch wood chips can be used in the new biorefinery processing chain for the production of 2-furaraldehyde, acetic acid, and cellulose pulp. In addition, the obtained lignocellulosic residue is also characterized. To produce a lignocellulosic material without pentoses and with the greatest amount of cellulose fiber preserved for future use, a novel bench-scale reactor technology is used. Studies were conducted utilizing orthophosphoric acid as a catalyst to deacetylate and dehydrate pentose monosaccharides found in birch wood, converting them to 2-furaldehyde and acetic acid. The results showed that, with the least amount of admixtures, the yields of the initial feedstock’s oven-dried mass (o.d.m.) of 2-furaldehyde, acetic acid, and lignocellulose residue ranged from 0.04 to 10.84%, 0.51 to 6.50%, and 68.13 to 98.07%, respectively, depending on the pretreatment conditions utilized. The ideal 2-furaldehyde production conditions with reference to the purity and usability of cellulose in residual lignocellulosic material were also discovered through experimental testing. The experiment that produced the best results in terms of 2-furaldehyde yield and purity of residual lignocellulose used a catalyst concentration of 70%, a catalyst quantity of 4%, a reaction temperature of 175 °C, and a treatment period of 60 min. It was possible to create pulp with a tensile index similar to standard printing paper by mechanically pulping the necessary LC residue with alkaline peroxide, proving that stepwise 2-furaldehyde production may be carried out with subsequent pulping to provide a variety of value-added goods.

Laboratory- to Pilot-Scale Fractionation of Lignocellulosic Biomass Using an Acetone Organosolv Process

Acetone organosolv fractionation of beech and birch wood at the lab-scale results in high sugar yields from the (hemi)cellulose and the isolation of a high-purity lignin. In this study, the process is scaled up to validate the technology at the pilot scale using industrial-size beech and birch wood chips and low liquid-to-solid ratios as a next step toward commercialization. Translation of the fractionation process to the pilot-scale showed a similar performance as compared to the lab-scale processing with a good conversion of the wood polymeric pentoses to mostly monomeric sugars and a high delignification. Continuous lignin precipitation by solvent evaporation using the LigniSep process resulted in the formation of nonsticky lignin aggregates with a good filterability. The improved lignin yields and advanced process design as compared to the traditional dilutive lignin precipitation approaches are likely to translate to a better process economy. The pulp washing efficiency and the recovery of (nonprecipitable) lignin from the aqueous hemicellulose stream still need to be improved for an efficient process design. However, the fractionation performance and high product concentrations in the spent liquor provide an excellent start position for improved process design at the commercial scale.

Trace elements, anions, and carbohydrates in the recirculating aquaculture system using woodchip denitrification, constructed wetland, and sand infiltration

Abstract A recirculating aquaculture system (RAS) aims to achieve fish production with negligible discharge into the environment. RASs have been applied for fish production in several countries, but nitrate removal is often a limiting factor for production increases. In this study, a pilot-scale RAS (10 tons of fish/year) was connected to a water treatment field which consisted of a denitrifying woodchip bioreactor (9 m × 14 m) filled with birch woodchips (Betula pendula), a constructed wetland (7.5 m × 6 m), and sand infiltration (16 m × 31 m) to achieve high water quality with low-maintenance treatment units. In the constructed wetland, a perennial common reed (Phragmites australis) was used in a well-drained soil for nutrient re-use. Concentrations of different elements, diluted anions, and selected hydrocarbons were monitored and quantified. Some Mn leaching occurred during the sand infiltration stage. However, Mn concentrations decreased towards the end of the experiment. Concentrations of total-Fe increased up to 2.75 mg L−1 and Mn up to 5 mg L−1 in the sand infiltration stage of the water treatment field, probably due to anoxic conditions and leaching of fine particles. This type of process design offers effective but low-maintenance treatment of circulating water.

Assessment of Different Binders for Activated Carbon Granulation for the Use in CO2 Adsorption

Abstract An eco-friendly method for the synthesis of granular activated carbon was developed in this study. Two types of activated carbon and three types of activated carbon granules have been obtained using different binders, and their properties have been determined. The approach requires adding other binders and waste materials to improve the granulation of activated carbon. Activated carbon was prepared from birch wood chips. Prepared carbon was granulated with a) gas generator tar, b) phenol-formaldehyde resin, and c) polyvinyl acetate to obtain granular activated carbon. This work aims to study the possibilities of using activated carbon adsorbents for CO2 adsorption. The activated carbon produced was characterized by BET, FTIR, and SEM. The adsorption behavior on CO2 was also studied. Granular activated carbons compression strength was enough to study it in an adsorption bed, and an optimal binder was to be phenol-formaldehyde resin and polyvinyl acetate. The obtained results show that activated carbon granules are suitable for CO2 adsorption and can be used, for example, for the removal of CO2 in the biogas upgrading process. As the sustainability problems are increasing, granules from waste materials could be promising materials for further studies.

Constructed wetlands with subsurface flow for nitrogen removal from tile drainage

Diffuse pollution from agricultural drainage is a severe problem for water quality and it is a major reason for the failure to accomplish “good chemical status of surface waters” according to the Water Framework Directive and for the eutrophication of both freshwaters and coastal waters. Constructed wetlands were proposed as a suitable tool for removal of nitrogen from agricultural drainage in the early 1990s. Until now, the vast majority of constructed wetlands designed to treat tile drainage were free-surface constructed wetlands. In 2018, three experimental constructed wetlands with horizontal subsurface flow were built to treat tile drainage from 15.73 ha watershed. The wetlands have a surface area of 79, 90 and 98 m2 and were planted with Phalaris arundinacea and Glyceria maxima in parallel bands. The substrate in the first two wetlands is gravel (4–8 mm) mixed with birch woodchips (10: 1 volume ratio). In one of those wetlands, the water level is kept 10 cm above the surface, in the second one the water is kept below the surface. The third wetland has 20 cm layer of birch woodchips on top of gravel. The mean total nitrogen concentration eliminations during one-year period were 61.2%, 62.6% and 70.9% for wetlands 1, 2 and 3, respectively. The average load removals amounted to 0.516, 0.323 and 0.399 g N m−2 d−1 or 1885, 1180 and 1457 kg ha−1 yr−1 in wetlands 1, 2 and 3 respectively. The plant uptake and nitrogen sequestration in aboveground biomass contributed only marginally to the overall nitrogen removal. The results revealed that the selection of the best option depends on the fact whether concentration or load is taken as the most important parameter.

Yield of Pulp, Dimensional Properties of Fibers, and Properties of Paper Produced from Fast Growing Trees and Grasses

Paper is produced mainly from wood fibrous pulps, which has been increasingly replaced by pulps from fast growing plants due to limited wood resources. In this work, properties of cellulosic pulps produced by the sulfate method from four fast growing grasses, poplar cultivar 'Hybrid 275', and European larch, as well as pine and birch wood chips, were compared. In addition, the cellulosic pulp yield, dimensions of fibers contained in the pulps and mechanical and optical characteristics of paper sheets produced from the pulps were compared. The pulp yield of the poplar cultivar 'Hybrid 275' (51.6%) was almost 5% higher than birch pulp (47.0%). Moreover, all of the investigated tensile properties of paper made from ‘Hybrid 275’ pulp were higher than for paper produced from birch pulp. Fast growing grasses, despite lower pulp yield (34.0 to 47.1%), showed comparable tensile properties to birch. Therefore, these pulps are promising raw materials for papermaking.

Influence of Moisture Content of Feedstock Materials on Briquettes Properties

Current contribution contains of results of experimental measurements performed within the determination of initial raw feedstock materials moisture content and its influence on final properties of subsequently produced briquettes. A birch wood chips samples with five different moisture contents, specifically 5.0%, 7.6%, 16.7%, 19.0% and 27.7%, were used for experimental investigations. Investigated briquette samples were produced by hydraulic high-pressure briquetting press Briklis, type BrikStar 30-12 with cylindrical pressing chamber of 50 mm. All investigated briquette samples were produced under the same conditions with constant adjustment of all parameters of used briquetting press. A basic physical-mechanical properties of investigated briquette samples were used as a criteria of investigations evaluation. All measured values were subjected to the statistical analysis. Final evaluation of measured values indicated that best results were achieved by briquette samples produced from feedstock material with moisture content equal to 7.6%. Evaluation of current investigation also proved that if moisture content was higher or lower, the quality of produced briquette samples decreased.

Direct Succinic Acid Production from Minimally Pretreated Biomass Using Sequential Solid-State and Slurry Fermentation with Mixed Fungal Cultures

Conventional bio-based succinic acid production involves anaerobic bacterial fermentation of pure sugars. This study explored a new route for directly producing succinic acid from minimally-pretreated lignocellulosic biomass via a consolidated bioprocessing technology employing a mixed lignocellulolytic and acidogenic fungal co-culture. The process involved a solid-state pre-fermentation stage followed by a two-phase slurry fermentation stage. During the solid-state pre-fermentation stage, Aspergillus niger and Trichoderma reesei were co-cultured in a nitrogen-rich substrate (e.g., soybean hull) to induce cellulolytic enzyme activity. The ligninolytic fungus Phanerochaete chrysosporium was grown separately on carbon-rich birch wood chips to induce ligninolytic enzymes, rendering the biomass more susceptible to cellulase attack. The solid-state pre-cultures were then combined in a slurry fermentation culture to achieve simultaneous enzymatic cellulolysis and succinic acid production. This approach generated succinic acid at maximum titers of 32.43 g/L after 72 h of batch slurry fermentation (~10 g/L production), and 61.12 g/L after 36 h of addition of fresh birch wood chips at the onset of the slurry fermentation stage (~26 g/L production). Based on this result, this approach is a promising alternative to current bacterial succinic acid production due to its minimal substrate pretreatment requirements, which could reduce production costs.

New catalytic strategies for α,ω-diols production from lignocellulosic biomass.

Catalytic strategies for the synthesis of 1,5-pentanediol (PDO) with 69% yield from hemicellulose and the synthesis of 1,6-hexanediol (HDO) with 28% yield from cellulose are presented. Fractionation of lignocellulosic biomass (white birch wood chips) in gamma-valerolactone (GVL)/H2O generates a pure cellulose solid and a liquid stream containing hemicellulose and lignin, which is further dehydrated to furfural with 85% yield. Furfural is converted to PDO with sequential dehydration, hydration, ring-opening tautomerization, and hydrogenation reactions. Acid-catalyzed cellulose dehydration in tetrahydrofuran (THF)/H2O produces a mixture of levoglucosenone (LGO) and 5-hydroxymethylfurfural (HMF), which are converted with hydrogen to tetrahydrofuran-dimethanol (THFDM). HDO is then obtained from hydrogenolysis of THFDM. Techno-economic analysis demonstrates that this approach can produce HDO and PDO at a minimum selling price of $4090 per ton.

Lipid production from hemicellulose with Lipomyces starkeyi in a pH regulated fed‐batch cultivation

This study investigated lipid production from the hemicellulosic fraction of birch wood by the oleaginous yeast Lipomyces starkeyi. Birch wood chips were thermochemically pretreated by hot water extraction, and the liquid phase, containing 45.1 g/l xylose as the major sugar, 13.1 g/l acetic acid and 4.7 g/l furfural, was used for cultivations of L. starkeyi CBS1807. The hydrolysate strongly inhibited yeast growth; the strain could only grow in medium containing 30% hydrolysate at pH 6. At pH 5, growth stopped already upon the addition of about 10% hydrolysate. In fed-batch cultures fed with hydrolysate or a model xylose-acetic acid mixture, co-consumption of xylose and acetic acid was observed, which resulted in a pH increase. This phenomenon was utilized to establish a pH-stat fed-batch cultivation in which, after an initial feeding, hydrolysate or model mixture was connected to the pH-regulation system of the bioreactor. Under these conditions we obtained growth and lipid production in cultures grown on either xylose or glucose during the batch phase. In cultivations fed with model mixture, a maximum lipid content of 60.5% of the cell dry weight (CDW) was obtained; however, not all xylose was consumed. When feeding hydrolysate, growth was promoted and carbon sources were completely consumed, resulting in higher CDW with maximum lipid content of 51.3%. In both cultures the lipid concentration was 8 g/l and a lipid yield of 0.1 g/g carbon source was obtained. Lipid composition was similar in all cultivations, with C18:1 and C16:0 being the most abundant fatty acids. Copyright © 2016 John Wiley & Sons, Ltd.

Erratum to: Preliminary fixed-bed downdraft gasification of birch woodchips

Erratum to: Preliminary fixed-bed downdraft gasification of birch woodchips

Characterization of Lignin Dissolved During Alkaline Pretreatment of Softwood and Hardwood

Various alkaline pretreatments were applied to Scots pine (Pinus sylvestris) and silver/white birch (Betula pendula/pubescens) wood chips and the characterization of sulfur-free lignin dissolved was performed. The behavior of lignin during these pretreatments (alkali charge 1–8% NaOH, time 30–120 minutes, and temperature 130–150°C) was studied mainly in terms of lignin removal efficiency and molar mass distribution of dissolved lignin. The amount of lignin in pretreatment liquors increased along with an increase in the alkali charge of 0.8–4.4% and 0.6–3.4% of o.d. pine and birch wood, respectively. The most significant parameter affecting the molar mass of the dissolved lignin was shown to be the alkali charge, since an increase in this parameter clearly increased the -values of dissolved lignin, varying from 2,260 g/mol to 7,050 g/mol and from 2,200 g/mol to 5,550 g/mol for pine and birch lignin, respectively.

Water Prehydrolysis of Birch Wood Chips and Meal in Batch and Flow-through Systems: A Comparative Evaluation

Water prehydrolysis can be used as a pretreatment to extract hemicelluloses and lignin from biomass prior to its conversion into value-added products. In this study, the effects of operational conditions such as reactor system, flow, particle size, and solids content during prehydrolysis of birch wood are compared, using the wood yield as indicator of pretreatment intensity. The results show that both batch and flow-through (FT) systems are equally effective in removing the carbohydrates from the wood. Increasing flow and decreasing particle size and solids content, however, facilitate the removal of lignin. This increased delignification is partly related to a lower extent of condensation reactions. A FT system is also advantageous for the recovery of the extracted sugars because degradation reactions are minimized. Furthermore, by applying elevated temperatures and short retention times, the sugars concentration in the hydrolysate might be only somewhat higher than that in a batch system.

Optimisation of Acetic Acid Lignofibre Organosolv Process

Birch wood chips were cooked in acetic acid in the presence of phosphinic acid according to the Lignofibre (LGF) organosolv process. The cooking trials were performed according to an experimental design with process time, temperature, and the presence (or absence) of alkaline pre-extraction as the factors. Delignification was enhanced by increased temperature and alkaline pre-extraction. Alkaline extraction also limited xylose hydrolysis, as well as the further degradation of xylose into furfural. Degradation and condensation reactions began to take place between dissolved carbohydrates and lignin at higher temperatures and longer cooking times. Formation of pseudolignin, most likely because of reactions between lignin and furfural, was also observed under the harshest cooking conditions. To avoid these unwanted side-reactions, minimise viscosity losses, and preserve the yield, the LGF process time should be limited to 3 to 4 h at 150 °C.

Preliminary fixed-bed downdraft gasification of birch woodchips

This paper investigated the possibilities of using birch wood chips for fixed-bed downdraft gasification. The preliminary air gasification resulted producer gas with an average composition of 11.5 % CO, 5.4 % CO2, 5.9 % H2, 0.38 % CH4 corresponding to a mean lower heating value of about 2 MJ/kg. The approximate size of woodchips used for gasification was around 11.5 mm for a maximum solid throughput of 0.65 kg/h. The obtained equivalence ratio (ratio between actual air fuel ratio and stoichometric air fuel ratio) as a result of air and biomass feed was close to 0.45 which was stable throughout the test. Producer gas left the gasifier at ca. 150 °C and was diverted for flaring owing to the level of low energy content. Despite availability, the option for gas to generate heat and electricity via integrated gas engine has not been utilized in the present case and remained for further ongoing research.