Fernando José Borges Gomes

Production of fermentable sugars from sugarcane bagasse by enzymatic hydrolysis after autohydrolysis and mechanical refining

The autohydrolysis process has been considered a simple, low-cost and environmental friendly technology for generation of sugars from biomass. In order to improve accessibility of enzymes during enzymatic hydrolysis as well as to allow the recovery of hemicellulose in the filtrate, the sugarcane bagasse was pretreated using autohydrolysis followed by a mechanical refining process. The autohydrolysis was carried out in three different conditions. Autohydrolysis at 190°C for 10min provided the highest overall sugar (19.2/100g raw bagasse) in prehydrolyzate. The enzymatic hydrolysis step was performed for all the post-treated solids with and without refining at enzyme loadings of 5 and 10FPU/g for 96h. A total of 84.4% of sugar can be recovered from sugarcane bagasse at 180°C for 20min with 5 FPU/g enzyme charge. The economic analysis for the proposed method showed that the bioethanol production can have a financial return larger than 12%.

Preliminary studies on furfural production from lignocellulosics.

Abstract This study focused on the production of furfural from agricultural and industrial biomass residues by a hydrodistillation process. Corncobs, sugarcane bagasse, and eucalypt wood were treated with sulfuric, hydrochloric, and phosphoric acids as catalysts, with different acid concentrations (1.5 to 5.2 mol.L −1). In addition, the eucalypt liquor from the auto-hydrolysis, kraft-dissolving pulp production process was also investigated as a source of furfural, using sulfuric and hydrochloric acids as a catalyst (0.9 and 3.9 mol.L −1) . Furfural yields of 30.2, 25.8, and 13.9% were achieved for corncob, sugarcane bagasse, and eucalypt wood, respectively, on the basis of biomass dry weight. The efficiency of conversion from pentose to furfural using eucalypt liquor from the auto-hydrolysis kraft process was 71.5% using HCl 3.9 mol.L −1 . Due to the presence of a high amount of pentose, corncob produced the highest amount of furfural, followed by sugarcane bagasse and then eucalypt wood.

Thorough Characterization of Brazilian New Generation of Eucalypt Clones and Grass for Pulp Production

Eucalypt wood is becoming the most important raw material for the pulp industries in South America. However, due to the high wood cost in comparison to other raw material sources, nonwoody materials are also being investigated aiming at pulp production. In this way, this paper aimed at the evaluation of eighteen eucalypt clones obtained from the Brazilian Genolyptus project, regarding their potential characteristics for pulp production. Aiming at the same goal, two species of elephant grass were also evaluated as alternative raw material sources. Through the analyses of the anatomic and chemical characteristics, five eucalypt clones and one elephant grass species were indicated for pulp production and biorefinery application. The results of this study indicate the high technological quality of Eucalyptus clones evaluated and indicate that they can be used for biorefinery applications since they have the suitable characteristics. In general, the eucalypt clones are less moist and denser and contain fewer minerals and extraneous materials than the elephant grass species, which make them more attractive for utilization in deconstruction studies aiming at production of bioproducts.

The Brazilian wood biomass supply and utilization focusing on eucalypt

Brazil has 8.51 million km2 of territorial area and a tropical climate. In 2010, the occupation of the Brazilian soil consists of 20.8% pasture, 6.8% agriculture, 0.8% forested areas, 61.0% natural forests, and 9.7% other areas. In 2012, of the total area of the country 3.25% (27.65 million ha) is occupied by soy bean cultivation and 1% (8.5 million ha) by sugar cane cultivation. In 2012, the main cultivated species in the country were Eucalyptus spp. (71.0%), Pinus spp. (21.75%), Acacia mearnsii and Acacia mangium (2.12%), Hevea brasiliensis (2.36%), and Schizolobium amazonicum (1.22%). From 2004 to 2012, the planted forest area growth was 50.4%. The main factor that boosted this growth was the demand of the pulp and paper, followed by wood-based panels sector. It is also notable the development of new planted forests in Brazil for energy purposes. In recent decades, scientific and technological advance shave resulted in significant improvements in productivity, resistance to diseases, uniform degree of the forest plantations, wood quality etc. Among the most researched species are the ones belonging to Eucalyptus gender for having excellent adaptability to the edaphoclimatic conditions in the country. The current average productivity of Eucalyptus is of 40.7 m3/ha·year. In some regions of the country the average productivity of Eucalyptus has reached 100 m3/ha·year. The Brazilian forestry industry uses mainly planted forests, and the pulp and paper industry consumes only this type of wood. The pulp and wood panel sectors are more technologically advanced in relation to the other wood products sectors.

Effect of Lignin Carbohydrate Complexes of Hardwood Hybrids on the Kraft Pulping Process

Lignin-carbohydrates complexes influence many chemical properties in the wood, such as difficult-to-remove lignin from Kraft pulps at the end of pulping due to the occurrence of lignin carbohydrates bonds. Therefore, this study aimed to study the influence of lignin-carbohydrate complexes on eucalyptus Kraft pulping. Spectroscopic techniques (13C NMR and HSQC-2D) were applied for the determination and quantification of lignin-carbohydrate complex (LCC) structures, and then evaluated the effect of LCC on Kraft pulping of eucalyptus hybrids. The analytical tools allowed the identification and quantification of the benzyl ether, γ-ester, and phenyl glucoside linkages of the lignin-carbohydrate complexes in eucalyptus hybrid wood. The glycosidic phenyl and γ-ester linkages are, respectively, more and less significant from the quantitative point of view. Analysis of 13C NMR of the samples showed that the eucalyptus hybrid GxGL contained high β-O-4 linkages content and also higher pulping yield than the other samples, suggesting that the linkages between lignin are more important than LCC linkages in pulping.

Composição química da madeira de eucalipto com diferentes níveis de desbaste

The objective of this study was to evaluate different thinning regimes in forest plantations of eucalypt (Eucalyptus grandis x Eucalyptus urophylla) clones to produce timber for cellulose and charcoal to verify whether this effect could affect the proportion of the chemical components of wood. The average initial spacing between plants was 3x3 m and the treatments were: T1= control, T2, T3and T4 with thinning 20%, 35% and 50% of the basal area, respectively. The results were analyzed by Tukey test at 5% probability. According to the results found the lignin content from treatment T4 was higher than that of the others; the groups of uronic acids of the T1 was similar to all other treatments, but the levels of T2 and T4 differed between them. The extractives content of T1was similar to the T2 and T3 and lower than that of theT4; the carbohydrates of T1 were similar to that of T3 and higher than the others. It was concluded that thinning increases the quality of the wood to be used as energy purposes, such as charcoal production, but it did not increase productivity for wood pulp and paper production.

Pulping-tailored fiber properties from a novel Brazilian Eucalyptus hybrid

Abstract The chemical composition and morphology of pulp fibers have a significant impact on the properties of fiber products. Pulp samples from a novel unique Eucalyptus triple hybrid [Eucalyptus grandis × (Eucalyptus urophylla × Eucalyptus globulus)] were obtained by various pulping processes – kraft, soda-anthraquinone (NaOH-AQ), and thermomechanical pulping (TMP). The chemical composition of the fiber surfaces was evaluated by X-ray photoelectron spectroscopy (XPS). The surface lignin content of NaOH-AQ pulp fibers was lower than that of the kraft counterpart. However, kraft pulp handsheets showed better physical and mechanical properties. XPS data strongly suggests that together with the pulp bulk chemical composition the xylan is more abundant on the surface of kraft fibers, which is reflected on their better mechanical properties. Moreover, the relatively low surface lignin content in TMP pulp compared to wood suggests that defibration takes place in the secondary wall, where lignin is less concentrated.

Enhancement of eucalypt pulp yield through extended impregnation cooking

Abstract The improvement caused by eucalypt chip impregnation on kraft pulping performance was assessed for terminating the cook at kappa in the range of 15–27 and at controlled residual effective alkali (REA) of 6–8 g/L NaOH. Extended impregnation cooking of eucalypt chips (EIC) increased about 1 % lignin- and HexA-free screen yield gains in relation to conventional cooking (CC), regardless of kappa number in the range of 15–27. The EIC technology allows for cooking eucalypt wood to kappa number up to 27, without rejects production, but without significant improvement in lignin- and HexA-free screen yield and with larger chlorine dioxide (ClO2) consume during bleaching. The optimum kappa number for both CC and EIC cooking was about 19 with similar refinability and strength properties for both technologies, CC and EIC. It was concluded that extended impregnation cooking is an attractive technique for enhancing bleached eucalypt Kraft pulp yield.

Addition of corn fiber xylan to eucalyptus and pinus pulp and its effect on pulp bleachability and strength

Abstract Corn fibers are a significant residue of agriculture due to the huge amounts, which has fueled interest in a more rational use of its components, particularly regarding hemicelluloses. The impact of hemicellulose redeposition on printer and writing (P&W) paper grade pulp properties are discussed in this paper. Xylans extracted from corn fibers (16.9 % xylans) by cold caustic extraction (CCE) were added to commercial brown pulps (eucalypt and pine) in the oxygen delignification (O-stage) and further bleached to 90 % ISO brightness. Hemicelluloses deposition occurred at variable degree (up to 7 % on pulp weight). Pulp bleachability was not impaired by xylan deposition for eucalypt and pine pulps. Xylan deposition onto fibers was more efficient in eucalypt pulp than pine. Pulp beatability and strength properties were improved by xylan deposition for P&W paper grades.

FINAL CHLORINE DIOXIDE STAGE AT NEAR-NEUTRAL pH FOR BLEACHING EUCALYPTUS PULP

It is well known that pH is an important parameter for controlling the eucalyptus pulp bleaching when using the final chlorine dioxide stage, since it affects the effectiveness of the process. Recommendations found in the literature for operating are in the 3.5 to 4.0 range. However, in this paper it was shown that final chlorine dioxide has better performance, with significant brightness gain while also preserving pulp quality, when it is operated at near neutral pH. This result can be explained by the generation of sodium bicarbonate in situ upon adding carbon dioxide at this stage.