Eucalyptus Wood Chips Research Articles

Co-pyrolysis of waste wood and plastic to produce quasi graphitic carbon: enhanced biochar properties for metal coatings through safe sequestration and green technology

Use of waste polystyrene as an additive in the preparation of biowaste derived char can provide significant new properties that enhance the performance of the epoxy coating on steel surface. This work establishes a cost-effective Quasi-graphitic carbon (QGC) derived from the co-pyrolysis of Eucalyptus wood chips and polystyrene as a mix in epoxy (EP) matrix for enhanced the coating properties. The QGC material was characterized by FTIR, XRD, Raman, SEM-EDX, TGA, etc. Results show the incorporation of 0.1 wt.% QGC to the EP matrix enhances corrosion resistance by 98.6 % and boosts mechanical properties with a 245.45 % increase in hardness and a 57.31 % rise in elastic modulus compared to pure EP coatings. Microscopic analysis reveals a smoother, more compact surface with fewer structural defects comapred to pure EP coating. Adhesion tests score the category of 4B, 5B, and water contact angle improve to 102.8°, compared to 61.6° for pure EP coatings. These eco-friendly materials, created through environmentally conscious processes can be a safe alternative to the conventional toxic chemicals used to protect against corrosion,particularly in marine environments.

Production of high-quality dissolving pulp from eucalyptus wood chips using deep eutectic solvent and elemental chlorine-free bleaching

Deep eutectic solvent (DES) provides promising alternatives to conventional pulping and cellulose purification with significantly lower energy consumption and impacts on the environment. In this work, choline chloride – lactic acid (ChCl-LA DES) pulping of eucalyptus wood chips combined with several ECF bleaching sequences was investigated to produce high-grade dissolving pulps. Initially, the dependency of DES pulping yield and delignification efficiency on the moisture content (MC) of used wood chips was evaluated. The results exhibited the crucial influence of the MC of wood chips on the delignification efficiency of DES pulping. DES pulping under optimized conditions resulted in an unbleached pulp with kappa number of 42, relatively high screened yield 48.1% and viscosity 796 cm3/g, as well as very low hemicellulose content, typically less than 3.8%. Further purification of the obtained pulp using D-Ep-D and OO-D-Ep-D bleaching sequences produces several dissolving pulps characterized by a high viscosity 695 cm3/g and brightness 89.5% ISO, indicating low degradation of cellulose during DES pulping. DES pulping exhibited considerable potential to remove the hemicelluloses from wood chips and produce high-quality dissolving pulps. This could be attained through shorter pulping operations conducted at a lower temperature and a higher screened yield compared to current dissolving pulp production operations.

Application of brewers’ spent grains as an alternative biomass for renewable energy generation in a boiler combustion process

In most industries that generate consumer products the main source of electrical energy comes from burning wood or fossil fuels in boilers. However, the use of these non-renewable fuels poses a huge problem for the current energy matrix and for the environment, which makes new alternatives necessary for a more environmentally friendly scenario. In view of this, our study evaluated the application of brewers’ spent grains (BSG) as an alternative biomass for energy generation in an industrial cogeneration system. For this, different blends of BSG and eucalyptus wood chips were used for steam generation. In addition, the effect of two different dehydration conditions on the drying kinetics of BSG were evaluated. The BSG presented an initial moisture content of 77.68%, 0.52% ash, mean particle size of 0.28 mm, density of 113 kg m–3, and lower calorific value of 17.84 MJ kg–1, making it suitable for energy recovery in a cogeneration system. Outdoor drying under external conditions can be applied to remove the moisture content from BSG, which is a low-cost strategy for further application in the drying process. From the biomass blends, the use of 80% BSG and 20% wood chips promoted better characteristics for application as fuel in a cogeneration system. The use of BSG promoted a reduction in the use of wood chips as fuel and generated a savings of approximately 9 thousand USD annually for the simulated system (80% BSG and 20% wood chips), a reduction of 82% of the cost, when comparing with a system using only wood chips. Therefore, the biomass by-product generated from beer production can be used to produce renewable energy in a cogeneration system, replacing the use of wood chips. The waste-to-energy strategy evaluated in this study can be a promising alternative for a circular economy transition, reducing the waste generated in breweries and promoting the recovery of renewable energy that can be applied in situ, making the entire industrial system become a biorefinery, using its main waste as biofuel to generate clean energy, promoting an energy transition to an increasingly cleaner energetical matrix.

Experimental study on the regulation of NOX in co-pyrolysis of maize straw and woody biomass

The NOX emissions from biomass as a carbon–neutral energy source during thermal conversion are of great concern. The research on the transformation law of NOX precursors in the thermal conversion process of biomass is an effective measure to regulate the nitrogen migration path of raw biomass and reduce the emission of NOX pollutants. In this study, maize straw was mixed with Eucalyptus wood chips and apple wood chips, respectively, and the slow pyrolysis experiment was carried out at 700 °C to control the nitrogen-containing products, the properties of char-N, tar-N and NOX precursor were studied by TGA, XPS, GC-MS and spectrophotometry, respectively.The results showed that, compared with the theoretical value of pyrolysis nitrogen products of maize straw and woody biomass alone, the addition of Eucalyptus wood chips increased the char-N yield, and the synergistic effect was the strongest under the condition of 50 wt.% addition ratio of +0.2980, the yield of char-N was 32.06 wt.%, apple wood chips was only observed to promote char-N at the addition ratio of 25 wt.%, the synergy intensity was +0.2013, the yield of char-N was 30.27 wt.%, and other experimental groups showed inhibition effect. At the same time, the co-pyrolysis system has a significant inhibitory effect on the NOX precursor nitrogen (NH3-N + HCN-N), among which the Eucalyptus wood chips addition test group has a more obvious inhibitory effect on NH3-N, the synergistic intensity reached the strongest at −0.5926 when the addition ratio was 25 wt.%; while the apple wood chips addition test group had a more obvious inhibitory effect on HCN-N, and the synergistic strength reached the strongest at −0.5798 when the addition ratio was 50 wt.%. In summary, regulating the migration path of nitrogen in the process of thermal conversion of biomass is helpful for cleaner utilization of biomass resources.

Optimizing the separation of xylose/xylan from eucalyptus woodchips in the autohydrolysis process

AbstractEffective separation of various components in biomass is critical for biorefinery. Autohydrolysis is a commercialized unit operation to remove hemicelluloses, such as xylan, in producing high‐quality cellulose (the so‐called dissolving pulp) in the pre‐hydrolysis kraft process. In the present study, the autohydrolysis of eucalyptus woodchips was investigated for the purpose of producing dissolving pulps, with a focus on the production of cellulose acetate grade dissolving pulp. First, the effects of liquid‐to‐solid ratio, maximum temperature, and time on hemicelluloses removal were comprehensively studied, and the total xylose saccharides concentration and total xylose saccharides yield were determined as a function of the P factor and log(Ro). The three‐variable Box–Behnken design of the response surface methodology was followed to optimize the autohydrolysis conditions, aiming to achieving the maximum removal of xylan. The as‐obtained optimal conditions were: liquid‐to‐solid ratio of 5.5 mL · g−1, maximum temperature of 165°C, and time of 120 min, with its P factor of 867 h and log(Ro) of 4.03. Under these conditions, the total xylose saccharides concentration was 16.43 g · L−1. Furthermore, the autohydrolysis yield was investigated. The results showed that the purity of as‐prepared cellulose substrate as a result of autohydrolysis at a P factor of 867 h (log(Ro) of 4.03) can meet the stringent requirement of cellulose acetate grade dissolving pulp. Furthermore, the pre‐hydrolysis liquor compositions were compared between the typical autohydrolysis conditions for rayon grade dissolving pulp (a P factor of 690 h and log(Ro) of 3.91) and the optimal conditions (a P factor of 867 h and log(Ro) of 4.03).

Effect of alkali charge on the performance of Eucalyptus globulus kraft pulps for tissue applications

Abstract The present study aimed to evaluate the effect of active alkali charge, in kraft cooking of Eucalyptus globulus wood, on the properties of the laboratory-produced tissue paper. Eucalyptus wood chips were cooked under similar conditions at four different active alkali (AA) levels of 16, 19, 21, and 23 % and DEDED sequence was used for subsequent ECF bleaching. Pulps were analyzed for their intrinsic viscosity, chemical composition, and fiber morphology, while the corresponding papers (20 g/m2) were examined for their strength properties, absorptivity, and softness. It was demonstrated that changes in the AA upon cooking, not only affected the chemical composition of the obtained pulps and their intrinsic viscosity, but also the fiber’s shape (e.g., curl and kink). These changes caused variations in the properties of laboratory-produced tissue papers. Thus, the increase in AA led to paper with lower tensile strength, but with better softness. Even though the increase of AA in cooking led to bulkier papers, their absorptivity was not significantly enhanced. This was explained, at least in part, by the lower water retention of the pulps obtained from cooking with higher AA.

Characterization of volatile organic compounds in food contact paperboards and elucidation of their potential origins from the perspective of the raw materials

Characterizing the volatile organic compounds (VOCs) in food contact paperboards and clarifying the origins of these VOCs are crucial to ensure the quality of the paperboards. Herein, VOCs present in raw paperboards (RPBs) intended for food contact and related raw materials comprising eucalyptus wood chips (WCs), bleached chemi-thermomechanical pulp (BCTMP), and dry pulp sheets (DPSs), were characterized using headspace solid-phase microextraction comprehensive two-dimensional gas chromatography quadrupole-time-of-flight mass spectrometry, by which 331, 191, 154, and 295 VOCs of 6 chemical categories were identified, respectively. It was found by chemometrics that bleaching significantly impacted the VOCs present in the RPBs and the DPSs in terms of both the number and chemical category of the VOCs, and that the DPSs exhibited higher correlations with the RPBs than other raw materials in terms of the VOCs. Most importantly, 153 VOCs present in the RPBs could be traced to the raw materials due to their co-occurrence, whereas the remaining 178 VOCs were proposed to originate from the RPBs production stage, relating to processing aids (22%), functional additives (17%), degradation products (51%), and contaminants (3%). Our results provided valuable references for the paper industry and were beneficial to promote food safety and the well-being of consumers.

Syngas Production for Fischer-Tropsch Synthesis from Rubber Wood Pellets and Eucalyptus Wood Chips in a Pilot Horizontal Gasifier with CaO as a Tar Removal Catalyst.

This research aims to investigate steam biomass gasification in a pilot horizontal gasifier using rubber wood pellets (RWPs) and eucalyptus wood chips (EWCs) for producing syngas with an H2/CO ratio range of 1.8 to 2.3 for Fischer-Tropsch synthesis. The study was divided into two parts. One was carried out in a lab-scale reactor to determine the effect of temperature and CaO on the gas product composition and the efficiency of tar removal. Another part was determined by investigating the effect of the steam/biomass (S/B) ratio on the produced H2/CO ratios in the pilot horizontal gasifier, which used the optimum conditions of temperature and % loading of CaO for tar removal according to the optimal conditions from the lab-scale gasifier. The lab-scale gasifier results showed that H2 and CO2 increased with temperature due to primary and secondary water gas reactions and hydrocarbon reforming reactions. The water gas shift and hydrocarbon reforming reaction depressed the CO and CH4 contents with increasing temperature, respectively. The optimum gasifying temperature was 900 °C, which obtained H2/CO ratios of 1.8 for both RWPs and EWCs. The tar yield decreased with increasing temperature and was less than 0.2 wt % when using CaO as a tar-cracking catalyst. The operation of the pilot horizontal gasifier at the operating condition of 900 °C and a S/B ratio of 0.5 using 0.2 wt % loading of CaO for tar removal also produced a H2/CO ratio of 2.0. The supply of an external heat source stabilized the gasifying temperature, resulting in a stable syngas composition and production rate of 2.5 and 2.7 kg/h with H2/CO ratios of 1.8 and 1.9 for the RWPs and EWCs, respectively. In summary, the horizontal gasifier is another effective designed gasifier that showed high-performance operation.

Synergetic effect of steam and activated tyre char on the selective production of levoglucosan-rich bio-oil from catalytic pyrolysis of wood chips

The catalysts used in the pyrolytic bio-oil upgrading process are either expensive or not efficient enough. This research aims to investigate and improve the catalytic capability of tyre char (TC), an otherwise low-value waste, as an effective catalyst for upgrading bio-oil derived from the pyrolysis of eucalyptus wood chips. Efforts were specifically made to tailor the TC properties to improve the selectivity of levoglucosan (LGA), a value-added bio-chemical in bio-oil. Experiments were carried out in a two-stage fixed-bed reactor in the absence and presence of steam (30 vol%) at different heating rates (10 °C/min and 110 °C/min). By using 3-Flex, SEM-EDX, XRD, XRF, CHNS, and synchrotron XAS analyses, it was found that zinc and sulphur added during the tyre manufacturing process were mainly present in the form of ZnS nanoparticles with a crystallite size less than 1 nm in the TC matrix. An overall deoxygenation extent of 31.7 wt% was achieved with original TC catalyst and slow heating rate of 10 °C/min. However, this number was increased to 49.2 wt% with steam activated TC and fast heating rate of 110 °C/min, and adding steam to the reactor at the optimum temperature of 500 °C. More specifically, the introduction of steam and activated TC to the pyrolysis reactor enhanced the transformation of heavy hydrocarbons to light species and value-added chemicals such as LGA and furfural, reaching 34.9 wt% and 11.3 wt% on the mass basis of bio-oil, respectively. The high catalytic performance can be attributed to the large porosity and better exposure of ZnS nanoparticles on the surface of the activated TC, and the influence of steam in shifting the reactions toward more selective production of light hydrocarbons.

Evaluation of the Gas Emissions during the Thermochemical Conversion of Eucalyptus Woodchips

The combustion of solid biomass in industrial boilers involves a sequence of processes that include heating, drying, devolatilization, and char conversion. To maintain a repeatable and fully controlled environment, and to monitor all the dynamics involved in the phenomena at a real scale, field-scale experiments become necessary to perform investigations. In this way, to evaluate different thermochemical conversion conditions of biomass particles under an oxidative atmosphere, and to quantify the emission of the main gas compounds continuously, a small-scale reactor was developed and presented in this paper. Hence, in this work, larger particles of eucalyptus are burned at 400 and 800 °C under different stoichiometric conditions to understand the differences between different biomass conversion regimes (gasification and combustion). The analysis of the mass loss at the different temperatures was characterized by only two different and consecutive stages for both thermochemical conditions. The first region does not present the influence on the air flow rate; however, there is a significant difference in the second region. This fact highlighted the importance of the diffusion of oxygen during the char conversion. Regarding the quantification of the gas compounds, an increase of around 3 times in the CO and CO2 emissions when gasification occurs was observed at 400 °C. However, at 800 °C, the same trend was verified, also verifying a considerable amount of CH4.

Immobilization and Application of the Recombinant Xylanase GH10 of Malbranchea pulchella in the Production of Xylooligosaccharides from Hydrothermal Liquor of the Eucalyptus (Eucalyptus grandis) Wood Chips.

Xylooligosaccharides (XOS) are widely used in the food industry as prebiotic components. XOS with high purity are required for practical prebiotic function and other biological benefits, such as antioxidant and inflammatory properties. In this work, we immobilized the recombinant endo-1,4-β-xylanase of Malbranchea pulchella (MpXyn10) in various chemical supports and evaluated its potential to produce xylooligosaccharides (XOS) from hydrothermal liquor of eucalyptus wood chips. Values >90% of immobilization yields were achieved from amino-activated supports for 120 min. The highest recovery values were found on Purolite (142%) and MANAE-MpXyn10 (137%) derivatives, which maintained more than 90% residual activity for 24 h at 70 °C, while the free-MpXyn10 maintained only 11%. In addition, active MpXyn10 derivatives were stable in the range of pH 4.0-6.0 and the presence of the furfural and HMF compounds. MpXyn10 derivatives were tested to produce XOS from xylan of various sources. Maximum values were observed for birchwood xylan at 8.6 mg mL-1 and wheat arabinoxylan at 8.9 mg mL-1, using Purolite-MpXyn10. Its derivative was also successfully applied in the hydrolysis of soluble xylan present in hydrothermal liquor, with 0.9 mg mL-1 of XOS after 3 h at 50 °C. This derivative maintained more than 80% XOS yield after six cycles of the assay. The results obtained provide a basis for the application of immobilized MpXyn10 to produce XOS with high purity and other high-value-added products in the lignocellulosic biorefinery field.

Adsorption Kinetics of Imidacloprid, Acetamiprid and Methomyl Pesticides in Aqueous Solution onto Eucalyptus Woodchip Derived Biochar

This work reports the application of a biochar (BC) derived from eucalyptus wood chips to remove pesticides (imidacloprid, acetamiprid and methomyl) from water. The pseudo-second order kinetic adsorption model is the best fit describing the adsorption of pesticides on BC. Furthermore, the Langmuir model correlated well with the adsorption isotherm data for acetamiprid and methomyl, while the Freundlich model was selected to explain the adsorption of imidacloprid on BC. The maximum adsorption capacities for methomyl, imidacloprid and acetamiprid on the BC material are 32.42, 14.75 and 4.87 mg g−1, respectively. The highest adsorption capacity of methomyl on the BC surface could be the result of multilayer adsorption suggested by the adsorption isotherm studies, with imidacloprid (or acetamiprid) monolayer being adsorbed on the BC surface. The structure, functional groups of pesticides, including their polarity, all played an important role contributing to the performance of biochar sorbent. Preferable interactions between the studied pesticides and the BC surface may include π-π interactions and hydrogen bonding. The steric aromatic entity in adsorbed imidacloprid and acetamiprid on the BC surface may hinder the possibility of other pesticide molecules approaching the available sorption sites on the surface.

Kinetic model analysis of mild autohydrolysis of eucalyptus woodchips for xylose production

The autohydrolysis process of eucalyptus hemicelluloses was studied. The effect of hydrolysis temperature and soaking time on the dissolution of hemicellulose from eucalyptus chips was considered, and the process conditions were further optimized by P factor. The kinetic equations for the hemicellulose reaction were derived by studying the reaction process of hemicellulose during the pre-hydrolysis of eucalyptus chips, based on the reaction activation energy of xylose from eucalyptus chips and the investigated reaction mechanism of eucalyptus pre-hydrolysis process. The results demonstrated the feasibility of efficient extraction and utilization of hemicellulose in the process of dissolving pulp preparation from eucalyptus chips.

Conversion of Wood into Hierarchically Porous Charcoal in the 200‐Gram‐Scale using Home‐Built Kiln**

AbstractThe wood‐to‐charcoal process (carbonization) is crucial in developing new materials at the lab for key technological processes nowadays. Unfortunately, laboratory carbonization methods are relatively costly and produce charcoal on a one‐gram scale. This work presents a simple‐to‐build and simple‐to‐operate homemade kiln that carbonizes Eucalyptus wood chips (yield of 30±1 %) and produces charcoal on the 200‐gram scale (two orders of magnitude higher). As‐made solid particles had the typical structure, composition, and chemical behavior of charcoal obtained from wood with standard carbonization procedures. Research of charcoal‐based materials is now probably more accessible.

Activated carbon preparation from eucalyptus wood chips using continuous carbonization\u2013steam activation process in a batch intermittent rotary kiln

The production of activated carbon from eucalyptus wood chips by steam activation in a 2000 kg batch intermittent rotary kiln with continuous carbonization–steam activation process conducted at 500 °C to 700 °C was studied. The activated carbon products were characterized by FTIR, SEM–EDS, Raman spectroscopy, and BET analysis. Percent yields, iodine number, and methylene blue number of the produced activated carbon materials were measured as well. It was shown that the percent yields of the activated carbon materials made in the temperature range from 500 to 700 °C are 21.63 ± 1.52%–31.79 ± 0.70% with capacities of 518–737 mg I2/g and 70.11–96.93 mg methylene blue/g. The BET surface area and micropore volume of the activated carbons are 426.8125–870.4732 m2/g and 0.102390–0.215473 cm3/g, respectively. The steam used in the process could create various oxygen containing surface functional groups such as –CO and –COC groups. In addition, it could also increase the amorphous nature of the activated carbon product. These properties of the activated carbon products are increased with increasing steam activation temperature from 500 to 700 °C. As a result, the activated carbon materials produced at activation temperatures of 600 °C and 700 °C exhibit higher adsorption.

Effects of Oxygen and Steam Equivalence Ratios on Updraft Gasification of Biomass

Several experimental datasets available on the gasification of different lignocellulosic feedstocks were used to correlate the flow of gasifying agents with the performance of updraft gasification in an autothermic 200 kWth pilot plant. The feedstocks used included eucalyptus wood chips, torrefied eucalyptus and spruce chips, lignin rich residues from biorefined straw and reed, shells of almond and hazelnut, which were gasified in flows of air, air and steam, oxygen, oxygen and steam. Thermal profiles inside the gasifier and gas quality in terms of incondensable gas and tar content were recorded and used to calculate the energy efficiency of converting solid feedstock into gaseous and liquid carriers. Common behaviors and parametric functionalities were identified to better understand the process and the most efficient tools to achieve the desired products. In analyzing data, the ratio steam to biomass was reported in terms of the equivalence ratio, ER(H2O) i.e., the fraction of the stoichiometric quantity required to convert the feedstock into H2 and CO2. The use of steam was useful to stabilize the process and to tune the H2/CO ratio in the syngas which reached the value of 2.08 in the case of oxy-steam gasification of lignin rich residues at ER(H2O) of 0.25. Larger use of steam depressed the process by lowering the average temperature of the bed, which instead increased steadily with ER(O2). The production of tar depends on the biomass type and a substantial reduction can be achieved with the torrefaction pretreatment. The same effect was observed increasing the residence time of the syngas in the reactor, typically achieved using oxygen instead of air as main gasification flow or reducing the ER(H2O). Oxy-steam gasification of torrefied wood led to the best results in terms of cold gas efficiency and low heating value when carried out in the ranger 0.23–0.27 of both the ERs.

Improvement of fermentable sugar recovery and bioethanol production from eucalyptus wood chips with the combined pretreatment of NH4Cl impregnation and refining

A combined pretreatment of NH4Cl impregnation and refining was developed to recover the fermentable sugars and improve the bioethanol yield. The xylose was recovered to decrease the cost of bioethanol production, moreover, the impregnation using nonmetal salt had little influence on the environment, and the energy consumption of the refining process was hugely reduced by the impregnation. The results showed that a high-temperature, short-time impregnation (170 °C, 10 min) led mainly to hemicelluloses degradation, where 97.4 % of the xylose was recovered from the impregnation liquor. 97.9 % of the cellulose in the refined solid substrate (SS) was converted to glucose by enzymatic hydrolysis, and 80.3 % of which was further fermented to bioethanol. The pretreatment energy efficiency was up to 260 g sugar/MJ, nearly three times higher than that using H2O impregnation and refining. Finally, the bioethanol yield (BY) and the xylose recovery reached to 189.75 and 150.95 g/kg wood, respectively.

Short-term Effect of Eucalyptus Wood-based Compost on Biological Fertility of Soils under Avocado Plantations

ABSTRACT This study investigated the effects of a eucalyptus-based compost on soil microbial community and enzyme activities of soils under avocado plantations in Limpopo, South Africa. It was hypothesized that compost application rate and time-post application would determine the abundance of biological organisms and enzyme activities. Experiments were conducted on 8-year-old ‘Hass’ avocado orchards. A repeated measures design with four compost treatments (0, 5, 10, and 15 ton ha−1 year−1), replicated three times was used. Thermophilic compost was prepared from locally sourced Eucalyptus wood chips (40%) and sawdust (20%), chicken manure (20%), and cattle manure (20%) stock feed. Soil samples were collected at three-month intervals for a period of nine months and analyzed for soil biota and enzyme activities. The results showed that compost application led to improved soil microbial counts and the effects were compost application rate and time dependent. The highest microbial counts were realized at 15 tons ha−1 and increased with time post compost application. Phosphatase, β-glucosidase, and urease were slightly increased at 10 and 15 tons ha−1 whereas fluorescein di-acetate was not affected by compost application rates. Compost application rates did not show a consistent effect on soil enzymes activities across sites and time.

Fluidized bed gasification of eucalyptus chips: Axial profiles of syngas composition in a pilot scale reactor

Air gasification tests have been carried out in a pilot scale bubbling fluidized bed gasifier, able to treat up to 100 kg/h of Eucalyptus wood chips, and operated, under chemical and thermal steady-state conditions, at different values of equivalence ratio. The results are reported in terms of the main process performance parameters and transfer coefficients, which indicate the fate of carbon in the different output streams (syngas, fines, tars). The results can be transferred to commercial scale reactors and confirm the technical feasibility of the air gasification of the biomass in the range 0.25–0.34 of equivalence ratio, yielding a good quality syngas, with a low heating value between 5000 and 6000 kJ/m3N,syngas. The measured axial syngas composition profiles along the reactor indicate a monotonic reduction of methane and carbon dioxide concentrations and an increase of that of hydrogen. This suggests that water gas shift and steam and dry reforming reactions play a significant role, together with a limited contribution of tar cracking reactions, probably enhanced by alkali and alkaline earth metallic species contained in the inorganic fraction of elutriated fines. Results can support the implementation of reliable numerical models of bubbling fluidized bed gasifiers and the optimisation of design/operating criteria.

Eucalyptus bark: A new source of fiber from the wood pulp industry for feeding to beef feedlot cattle

Our objectives were to compare the effects of feeding eucalyptus bark or eucalyptus wood chips, both by-products from the pulp industry, on voluntary feed intake, animal performance, and physiological variables of heifers finished on high-concentrate diets. Forty-eight British-breed heifers (Angus, Hereford, and their crosses) that were 22 to 24 mo of age and had an initial BW of 355 ± 8 kg were used. Four heifers were allocated to each of the 12 pens (experimental units). The experiment was a randomized complete block design with 2 treatments and 6 replications each. The 2 different fiber sources (wood chips or bark) were included in the fattening diet in the same proportion (8.9% DM basis). The rest of the ingredients in the diet were the same. The final diet was offered 3 times per day, and heifers were fed for 84 d. Fiber source (wood chips vs. bark) did not affect ADG or G:F ( P > 0.10). However, DMI ( P < 0.01), DP ( P = 0.04), and hot carcass weight ( P = 0.06) were greater in heifers fed with bark compared with those fed with wood chips. Heifers from the bark treatment spent less time ( P = 0.02) chewing than heifers from the wood chips treatment. In conclusion, bark could be used as a source of fiber for finishing cattle in high-concentrate diets at the same levels as wood chips. This finding is relevant for the feedlot industry because eucalyptus bark has no industrial uses and would represent a cheaper fiber source than wood chips.