Pine Chips Research Articles

Flowability of Crumbler Rotary Shear Size-Reduced Granular Biomass: An Experiment-Informed Modeling Study on the Angle of Repose

Biomass has potential as a carbon-neutral alternative to petroleum for chemical and energy products. However, complete replacement of fossil fuel is contingent upon efficient processes to eliminate undesirable characteristics of biomass, e.g., low bulk density, variability, and storage-induced quality problems. Mechanical size reduction via comminution is a processing operation to engineer favorable biomass flowability in handling. Crumbler rotary shear mill has been empirically demonstrated to produce more uniformly shaped particles with higher flowability than hammermilled biomass. This study combines modeling and experimentation to unveil fundamental understandings of the relation between granular particle characteristics and biomass flow behavior, which elucidate underlying mechanisms and guide selection of critical processing parameters. For this purpose, the impact of critical material attributes, including particle size (2–6 mm), particle shape (briquette, chip, clumped-sphere, cube, etc.), and surface roughness, on the angle of repose (AOR) of milled pine chips were investigated using discrete element method (DEM) simulations. Forest Concepts Crumbler rotary shear system is used to produce milled pine particles within the same size range considered in DEM simulations. AOR of different sets of these particles were measured experimentally to benchmark DEM results against experimental data. Specific energy consumption for the comminution of biomass with different particle size and moisture content are measured for technoeconomic analysis. Our results show that the smaller size (2 mm) of pine particle achieves better followability (i.e., smaller AOR) while the energy cost of comminution is significantly higher and bulk density is almost the same as the 6-mm pine particles. For the 2-mm particle size, Crumbles from veneer have better flow properties than Crumbles from chips. Contrarily, no significant difference was observed between the AOR of the two materials for the 6-mm particle size. Furthermore, from DEM simulations, mechanical interlocking between particles was found as a dominant factor in determining AOR of complex-shaped particles such as milled pine, which cannot be accurately captured by using simple particle shapes (e.g., mono-sphere) with a rolling resistance model. Conversely, clumped-sphere model alleviates this limitation without increasing computational cost significantly and can be used for accurate representation of biomass granular particles when simulating free-flow behavior.

Delignification efficiency of various types of biomass using microwave-assisted hydrotropic pretreatment

The use of a method of an effective delignification of lignocellulosic biomass is a key stage of designing processes of its microbiological conversion e.g. for the purposes of the production of cellulosic ethanol. The study was aimed at evaluating the effectiveness of microwave-assisted hydrotropic pretreatment using sodium cumene sulfonate (NaCS) for the delignification of pine and beech chips and wheat straw. Research results presenting the impact of process parameters of microwave-assisted hydrotropic delignification confirm a high effectiveness of this method of pretreatment of lignocellulosic biomass. The observed effects included changes in the composition of the biomass and an increased susceptibility of cellulose to the subsequent enzymatic hydrolysis. The use of microwave heating combined with an addition of hydrotrope of 40% w/v NaCS and 117 PSI for 60 min enabled a reduction of the absolute concentration of lignins by 36.58% in pine chips, by 57.68% in beech chips, and by 74.08% in wheat straw. After enzymatic hydrolysis was conducted, the highest concentration of glucose: 463.27 ± 11.25 mg glucose/g (hydrolysis yield 46.76 ± 1.14%) was obtained from the wheat straw, while 327.70 ± 22.15 mg glucose/g (hydrolysis yield 35.13 ± 2.37%) was acquired from the beech chips, and only 50.77 ± 0.75 mg glucose/g (hydrolysis yield 6.63 ± 0.10%) was obtained from the pine chips. Microwave-assisted hydrotropic delignification in the optimum process conditions additionally allows a complete removal of hemicellulose from biomass, which improves the effectiveness of enzymatic hydrolysis. Due to a significant reduction of lignin and hemicellulose concentration in biomass, cellulose—which is susceptible to enzymatic hydrolysis and a source of carbon in biosynthesis processes—becomes the main biomass component.

Addition of biomass ash as a promising strategy for high-value biohythane production from the organic fraction of municipal solid waste

In this work, the effect of adding ash from combustion of six locally available biomass types, namely common reed (Phragmites australis), corn stover, eucalyptus sawdust, hazelnut shells, pine chips, and rice husks at different concentrations (2.5, 5, 10, and 20 g/L) on H2 production from the organic fraction of municipal solid waste (OFMSW) was first investigated through batch experiments. The maximum cumulative H2 production of 1124 ± 3.21 mL was achieved using 5 g/L of rice husk ash (RHA), increasing by 644% compared to the control. Then, in a semi-continuous two-stage biohythane production process, the first reactor dedicated to H2 production was supplemented with 5 g/L of RHA and its performance was evaluated at three HRTs (3, 2, and 1 day). The results showed that the highest steady-state volumetric H2 production rate (554 ± 5.48 mL/L/d) and H2 yield (184.7 ± 1.83 mL/g-VSadded) were obtained at 2-day HRT. In the subsequent CH4 production stage, of the three HRTs tested (12, 8, and 4 days), the 12-day HRT resulted in a maximum volumetric CH4 production rate and CH4 yield of 321 ± 2.39 mL/L/d and 727.2 ± 5.46 mL/g-VSadded, respectively, under steady-state conditions. Throughout both stages, the pH remained within a suitable range without the addition of any commercial reagents. The overall energy yield of the two-stage process was found to be 31.2 kJ/g-VSadded, which corresponded to a total COD removal efficiency of 96%. Moreover, the composition of biohythane (H2 + CH4) obtained met the standards of a clean hythane fuel.

Bio-Wastes as Aggregates for Eco-Efficient Boards and Panels: Screening Tests of Physical Properties and Bio-Susceptibility

Screening tests were developed or adapted from RILEM recommendations, standards and past studies, and carried out to characterize some agro-industrial wastes and to assess their feasibility as aggregates for eco-efficient building composites. Spent coffee grounds, grape and olive press waste and hazelnut shells were used, as well as maritime pine chips as control material. Particle size distribution, loose bulk density, thermal conductivity and hygroscopicity properties were analysed. The selected bio-wastes did not show good thermal insulation properties if compared with some bio-wastes already studied and used for thermal insulation composites. Values of loose bulk density and thermal conductivity were between 325.6–550.5 kg/m3 and 0.078–0.107 W/(m·K); moisture buffering values higher than 2.0 g/(m2·%RH). Biological susceptibility to mould and termites were also tested, using not yet standardized methods. The low resistance to biological attack confirms one of the greatest drawbacks of using bio-wastes for building products. However, final products properties may be changed by adding other materials, pre-treatments of the wastes and the production process.

Characterization of thermomechanical pulp made from pine trees infected with nematodes

Pine wilt is a lethal disease caused by the nematode Bursaphelenchus xylophilus. It causes tree death by blocking water and nutrient uptake in pine trees. Pine trees infected by these nematodes are used as fertilizer or fuel for thermal power plants, but their utilization is still only about 37%. To increase the utilization of the infected trees, this study investigated whether the shredded wood chips prepared from them could be used as raw materials for manufacturing thermomechanical pulp (TMP) and chemithermomechanical pulp (CTMP). TMP and CTMP prepared from the infected pine chips showed fewer pitch contents and better strength properties than those made from domestic pine. In conclusion, if the nematode-infected pine was used as raw materials for manufacturing TMP and CTMP, it is expected that it would contribute to the diversification of raw materials along with a high-temperature insecticidal effect. Keywords: Pine wilt, nematode disease, thermomechanical pulp, chemithermomechanical pulp, pulp strength, insecticidal effect  

The chemical and physical properties of steam-exploded wood at different temperatures and times at the same severity as a dietary fiber source

The chemical and physical properties of steam-exploded pine chips were analyzed by varying the temperature (190 °C to 230 °C) and time (1.5 min to 20.0 min) of steam explosion at the same severity factor (Ro), i.e., 4.0. Then, their potential as a dietary fiber source was evaluated. Overall, the chemical properties, e.g., solid recovery, cellulose, hemicellulose, and total dietary fiber content, showed a tendency to decrease as the temperature increased as well as an increasing lignin content. The physical properties, e.g., water-holding capacity, oil-holding capacity, and swelling capacity, showed decreased values in pine chips subjected to steam explosion at a temperature of 210 °C or greater. The chemical and physical properties of the steam-exploded pine chips, which were subjected to steam explosion at different temperatures and times at the selected Ro) considerably changed, starting at a temperature of 200 °C for 11.5 min. Even with the same severity factor, the steam-exploded pine chips at a temperature of 200 °C for 11.5 min showed the greatest improvement in the physical properties, i.e., water holding capacity (8.3 g/g), oil holding capacity (6.8 g/g), and swelling capacity (4.9 mL/g).

A set of hysteretic nonlinear contact models for DEM: Theory, formulation, and application for lignocellulosic biomass

A monosphere discrete element method (DEM) model is introduced for elucidating the bulk mechanical behavior of granular biomass. This model considers each sphere as a representative elementary volume in bulk particles and is highly scalable in computation. To compensate for the simplification of particle shapes, we propose a set of hysteretic nonlinear contact models for approximating the bulk strain-hardening phenomena of granular biomass in handling and storage conditions. These contact models comprise of simple polynomial and/or exponential functions to allow for easy calibration. To ensure numerical stability, we have derived unconditionally stabilized viscous damping force models. The resultant DEM model is implemented in LIGGGHTS-INL and applied to simulate an axial compressibility test for milled pine chips. Results show that the DEM model can reproduce the bulk stress–strain profiles of the physical samples and that the predicted bulk compressibility and constrained modulus under repeated compression agree reasonably with the experimental data.

Effect of Steam Explosion Condition on the Improvement of Physicochemical Properties of Pine Chips for Feed Additives

Dietary fiber is considered a feed ingredient with high nutritional value in the broiler feed industry. Pine chips contain a large amount of dietary fiber and require some modification for use as broiler feed. In this study, pine chips were subjected to steam explosion under different severity factor (Ro) conditions to improve the chemical and physical properties of dietary fiber. The highest water-holding capacity, oil-holding capacity, and swelling capacity were found for Ro 4.0, followed by Ro 4.5 and 3.5. The optimal condition for the steam explosion was determined to be Ro 4.0 (reaction temperature of 210°C, and reaction time of 6.0 min). Under these conditions, the water-holding capacity, oil-holding capacity, and swelling capacity of steam-exploded pine chips were 8.3 g/g, 6.5 g/g, and 5.0 mL/g, respectively. This study may contribute to the application of lignocellulose and related products in the broiler feed industry.

Ammonia Fiber Expansion Combined with White Rot Fungi to Treat Lignocellulose for Cultivation of Mushrooms.

In order to improve the degradation efficiency of lignocellulose while increasing the yield of mushrooms, white rot fungi treatment (Pleurotus ostreatus, Pleurotus eryngii, and Pleurotus geesteranus) combined with ammonia fiber expansion was proposed as a method for treating lignocellulose (Pennisetum sinese, salix chips, and pine chips) for mushroom cultivation. Compared with treatment using either ammonia fiber expansion or white rot fungus, the combined treatment significantly improved lignocellulose degradation rate by 10–20% and reduced the time required significantly. Among them, P. geesteranus was the most effective bacterium for the combined treatment of lignocellulose. Ammonia fiber expansion-treated lignocellulose contributed to mycelial growth and increased the activity of three lignin hydrolase enzymes (laccase, manganese peroxidase, and lignin peroxidase) and mushroom yield. The mushroom yield was increased by 44.6%. The combined treatment method proposed in our study improves lignocellulose resource utilization and is therefore useful in the treatment of agricultural solid organic waste.

Volatile matter values change according to the standard utilized?

In lignocellulosic biomass, the volatile matter can vary from 65 to 85%. Different standards are described in the literature for obtaining this parameter. However, it is observed that some studies of regression models have not considered these differences. They create a volatile matter content database, where the standards for obtaining the same parameter are different. Thus, the objective of the study was to verify whether different standards for volatile matter present statistically equal values. That is if they can be compared with each other, without danger of bias. For this, three types of biomasses of Brazil used were used (eucalyptus chips, pine chips, and sugarcane bagasse). The samples were collected, size reduction, size separation, and stored in the laboratory. Three standards of the American Society for Testing and Materials (ASTM D1762, ASTM E872, ASTM D3175) and one standard of the International Organization for Standardization (ISO 18123) were tested. The experimental design was completely randomized, consisting of four treatments and five replications. The central limit theorem was tested in some literature databases of the volatile matter. The results showed statistical differences when changing the type of standard used. For eucalyptus sawdust, the four standards resulted in methodologies with different averages. Still, the central limit theorem was not observed in some databases of different articles. This was explained by the non-standardization of a single standard when grouping data from different works. Therefore, different volatile content standards produce different results and when comparing values, it is important to take this assumption into account.

Biochar Stability in a Highly Weathered Sandy Soil under Four Years of Continuous Corn Production

Biochar is being considered a climate change mitigation tool by increasing soil organic carbon contents (SOC), however, questions remain concerning its longevity in soil. We applied 30,000 kg ha−1 of biochars to plots containing a Goldsboro sandy loam (Fine-loamy, siliceous, sub-active, thermic Aquic Paleudults) and then physically disked all plots. Thereafter, the plots were agronomically managed under 4 years (Y) of continuous corn (Zea Mays, L.) planting. Annually, incremental soil along with corresponding bulk density samples were collected and SOC concentrations were measured in topsoil (down to 23-cm). The biochars were produced from Lodgepole pine (Pinus contorta) chip (PC) and Poultry litter (PL) feedstocks. An untreated Goldsboro soil (0 biochar) served as a control. After four years, SOC contents in the biochar treated plots were highest in the top 0–5 and 5–10 cm depth suggesting minimal deeper movement. Declines in SOC contents varied with depth and biochar type. After correction for SOC declines in controls, PL biochar treated soil had a similar decline in SOC (7.9 to 10.3%) contents. In contrast, the largest % SOC content decline (20.2%) occurred in 0–5 cm deep topsoil treated with PC biochar. Our results suggest that PC biochar had less stability in the Goldsboro soil than PL biochar after 4 years of corn grain production.

Pilot verification of a two-stage fluidized bed gasifier with a downer pyrolyzer using oxygen-rich air

A novel two-stage fluidized bed gasification system coupling a downer pyrolyzer and a riser gasifier was proposed, and a pilot facility of 15 kg/h of feedstock was further built and tested, by which the resulting technology gains its advantages of realizing the two-stage gasification principle in fluidized beds and having the large tolerance to biomass quality and size. Gasification of pine chips was in turn investigated at various equivalent ratios of air by changing the O2 concentration of gasifying agent composed of nitrogen and oxygen. The pilot facility was successfully operated at an ER value of 0.15, which generated 1.33 Nm3 product gas per kilogram of feedstock and containing 26.5% CO, 13.6% CO2, 8.89% H2, 12.6% CH4 and 0.63% CnHm. The LHV of the obtained fuel gas was as high as 9.35 MJ/Nm3 with a reasonably low tar content at 8.08 g/Nm3. By increasing the ER from 0.15 to 0.3, the temperatures of the pyrolyzer and gasifier were increased from 790 to 823 °C and from 881 to 925 °C, respectively. The gas yield was decreased to 1.1 Nm3/kg to have a reduced cold gas efficiency of 65.5% and a lower tar content of 4.35 g/Nm3 in the gas. These thus verified the technical feasibility of the proposed two-stage gasifier consisting of a downer and a riser.

Corn Grain and Stover Nutrient Uptake Responses from Sandy Soil Treated with Designer Biochars and Compost

Biochars are used for soil fertility improvement because they may contain certain elements that plants use as nutrients. However, few studies have demonstrated enhanced crop nutrient uptake. Our study examined nutrient uptake responses of corn (Zea Mays L.) grain and stover over 4 years (Y) after a Goldsboro sandy loam (fine-loamy, siliceous, sub-active, thermic Aquic Paleudults) received different designer biochars and a compost. The designer biochars were produced from lodgepole pine (Pinus contorta) chip (PC), poultry litter (PL), blends with switchgrass (SG; Panicum virgatum), and a SG compost alone. Topsoil treated with 100% PL biochar and blended PC:PL biochar had significantly greater Mehlich 1 (M1) extractable P, K and Na contents compared to the control or other treatments. No significant differences were detected in annual grain nutrient concentrations. In the first corn stover harvest (Y1), significantly greater concentrations of P and K were taken up after treatment with 100% PL biochar, with PC:PL blend and with SG when compared to control. By the fourth corn stover harvest (Y4), nutrient uptake between treatments was not significantly different. Biochar impact on corn stover P, K and Na concentrations was time dependent, suggesting that repeated biochar applications may be needed.

X-ray computed tomography-based porosity analysis: Algorithms and application for porous woody biomass

The properties of lignocellulosic biomass, such as bulk physical, thermal, and mechanical properties, as well as the mobility of enzymes or catalysts, are largely affected by porosity, pore structures, and pore size distribution. While X-ray computed tomography (CT) has been introduced to effectively produce 3D volumetric images of material microstructure, a quantitative porosity analysis from the 3D images has never been done. This work introduces a first-of-its-kind X-ray CT-based quantitative porosity analysis method and applies the developed toolkit to characterize the internal porosity distribution of loblolly pine. A sample loblolly pine chip was scanned by a nano-resolution X-ray CT system and digitally reconstructed after a sequence of image processing operations. A comprehensive porosity analysis was then performed to quantify the envelope porosity, the spatial distribution of local porosity, and the directional porosity. Solutions to the various challenges in image processing, porosity calculation, and large data handling are provided.

Techno-economic analysis for co-processing fast pyrolysis liquid with vacuum gasoil in FCC units for second-generation biofuel production

National Renewable Energy Laboratory (NREL) and Petrobras have worked closely to develop process models and analysis approaches to assess the economic feasibility of co-processing bio-oils (pyrolysis oils) with fossil feedstocks in petroleum refinery unit operations. Petrobras conducted co-processing experiments with pine-derived bio-oils and Brazilian vacuum gasoil (VGO) at typical operating conditions on their 200 kg/h demonstration-scale fluid catalytic cracking (FCC) unit. NREL evaluated the experimental yield data and developed novel modeling approaches to simulate and optimize co-processing scenarios. Within the uncertainties of measurements and the simplified refinery models used, the process modeling and techno-economic analysis (TEA) results identify conditions in which co-processing bio-oils could be economically feasible for the case of refiners purchasing VGO, expanding prior work demonstrating technical feasibility.TEA scenarios show a high potential for bio-oil co-processing to be economically attractive for petroleum refiners for benchmark crude oil prices at $70 (U.S. dollars) per barrel using up to 5 wt% bio-oil produced with typical fast pyrolysis technology (≤400 t/d) fed with dried pine chips. For oil prices per barrel of $55–$60, up to 10 wt% bio-oil could be co-processed profitably if produced in pyrolysis plants performing at an “nth-plant” level, feeding 2,000 t/d with dried pine chip feedstocks producing bio-oil at $48–$56 per barrel from feedstock ranging from $99-$132 per t ($90–$120 per ton). Alternatively, low-price biomass feedstocks could make bio-oil co-processing viable at lower oil prices in both cases.

Viability analysis of pine sawdust drying in a fountain dryer

The article presents analysis of physicochemical properties of pine sawdust originating from the area of the Knyszyńska Forest, in the context of possibility of their drying in a fountain dryer. Number of tests were carried out on dry pine chips of 45% moisture, such as: chemical composition, calorific value, ash content as well as morphological changes of dried material. The water storage mechanism in chips and the mechanism of formation of a fountain bed were also discussed. Based on the obtained results, several technical solutions and modifications of the fountain dryer were proposed. These modifications enable the sawdust of heterogeneous size and shape to be dried in a fountain drier as well as additional functional properties.

Low Emissions Resulting from Combustion of Forest Biomass in a Small Scale Heating Device

The paper concerns the analysis of harmful emissions during the combustion process in households. The subject of the analysis is a low emission heating device with an output of 50 kW for burning biomass of forest origin (low-quality hardwoods or softwoods). The proposed boiler is automatically fed from the connected container by means of a screw conveyor. In this way, the optimum amount of fuel is supplied for maximum heat output (adjustment of the ratio of primary air to fuel). The proposed biomass heating system is equipped with a primary and secondary air supply system and exhaust gas sensors. This ensures optimal regulation of the air mixture and efficient and clean combustion. Proper control of the combustion process, control of the air supply by means of a lambda sensor and power control of the system ensure a low-emission combustion process. The system precisely adjusts to the heat demand. This results in highly efficient heating technology with low operating costs. In the presented work, the emission of exhaust gases from the proposed heating device during the combustion of woodchips and beech–oak pellets were measured. It is demonstrated that the proposed design of the boiler equipped with intelligent control significantly reduces emissions when the biomass solid fuels are used, e.g., CO emissions from beech and oak chips and pellets in the low-emission boiler—18 extract pipes shows the value <100 ppm, which is even lower than when gas is burned in the other boilers; on the other hand, the pine chips show even higher emission when burned in the low-emission burner. Consequently, the choice of biomass source and form of the fuel play some role in the emissions observed.

Effect of Biomass Carbonization on the Grinding of Coal/Biomass Mixtures.

To increase the co-firing ratio of biomass in existing pulverized coal-fired power plants, biomass should be pulverized to obtain a particle size suitable for combustion. However, evaluation of the particle size distribution of each coal and biomass mixture via traditional fuel analysis is difficult. Because coal does not contain neutral sugars, the particle size distribution of biomass in the mixture can be estimated based on its neutral sugar content. The current study was conducted to evaluate the effect of biomass carbonization on the grinding process via neutral sugar analysis. Mixtures of coal and carbonized pine chips with three different degrees of carbonization were prepared and ground using a Hardgrove grindability index mill. In the pulverized mixtures of low carbonized biomass and coal, the biomass content at all particle size ranges was nearly the same as that of the input feedstock. As the degree of biomass carbonization increased, the biomass content in the mixture of large particle sizes was decreased, whereas it was increased in the mixture of small particle sizes. The current study indicated that particle size distribution of coal and biomass in the pulverized mixture depends on the degree of carbonization of biomass.

Alkaline sulfonation and thermomechanical pulping pretreatment of softwood chips and pellets to enhance enzymatic hydrolysis

To assess the impact of alkalinity on sulfonation and the enzyme-mediated hydrolysis of softwood cellulose, Lodgepole pine chips were impregnated with 8% sodium sulfite and increasing loadings of sodium carbonate before thermomechanical pulping. It was apparent that alkali addition enhanced lignin sulfonation with an additional 4% loading of sodium carbonate proving optimal. TEM indicated that sulfonation predominantly occurred within the secondary-cell-wall lignin, increasing cellulose accessibility to the cellulase enzymes. Although increasing alkalinity did not significantly enhance lignin sulfonation, likely due to the lower acetyl content of the softwood chips, it increases mannan solubilization. Despite their smaller particle size, softwood pellets were more poorly sulfonated, probably due to their higher lignin content and lower amount of acid groups. This more condensed lignin structure was confirmed by 2D-NMR and GPC analyses which indicated that the EMAL derived from softwood pellets contained less native β-O-4 linkages and had a higher molecular weight.

Microwave-Assisted Degradation of Biomass with the Use of Acid Catalysis

The aim of the study was to assess the effectiveness of microwave pretreatment combined with acid catalysis in the decomposition of various types of biomass (pine and beech chips and hemp stems). It was clearly demonstrated that sulfuric acid was a catalyst enabling the most effective decomposition of the tested plant biomass, guaranteeing the highest concentrations of simple sugars released. Acid catalysis with 1% v/v sulfuric acid combined with microwave radiation provided high glucose concentrations of 89.8 ± 3.4, 170.4 ± 2.4 and 164.6 ± 4.6 mg/g for pine chips, beech chips and hemp stems, respectively. In turn, the use of nitric acid promoted the degradation of hemicellulose, which resulted in high concentrations of galactose and xylose, i.e., 147.6 ± 0.6, 163.6 ± 0.4 and 134.9 ± 0.8 mg/g of pine chips, beech chips and hemp stems, respectively, while glucose levels remained relatively low. It was also demonstrated that the undesirable dehydration of sugars such as glucose and xylose is more pronounced in sulfuric acid than nitric acid processes. The use of H2SO4 and increased pressure generated 5-hydroxymethylfurfural (5-HMF) and furfural at a concentration of ca. 12 and 6 mg/g, 10 and 45 mg/g and 14 and 30 mg/g, of pine chips, beech chips and hemp shoots, respectively. Our studies confirmed the usefulness of the combined use of microwaves and acid catalysis in the degradation of softwood, hardwood and non-wood plant biomass. It should be emphasized that obtaining high concentrations of released simple sugars (as potential substrates in biosynthesis), while maintaining low levels of toxic by-products (inhibitors), requires precise selection of process parameters such as pressure, exposition time and type of acid catalyst.