Effect of Chemical and Steam Explosion Pulping on the Physical and Mechanical Properties of Sugarcane Straw Pulp Trays (original) (raw)
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Biomass and Bioenergy, 1998
AbstractÐThe utilization of steam explosion technology for the production of cellulose pulps was evaluated at a bench scale using wheat straw as raw lignocellulosic material. Steam explosion was used either as a pretreatment method to achieve the fractionation of the straw into its constitutive polymers, or as a rapid pulping method for the production of unbleached chemical pulps from alkali-impregnated straw. In the fractionation process straw was pretreated by steam explosion at temperatures comprised between 205 and 2308C, and a reaction time of 2 min. The exploded ®ber was washed three successive times to yield a hemicellulosic sugars-rich solution. The recovered ®ber was deligni®ed by alkali at 1608C for 60 min. The alkali lignin was recovered by ®ltration after acidi®cation of the black liquor. The resulting ®ber was screened to separate the ®nes from the pulp. The latter was bleached and viscose-grade cellulose obtained. By-products of the process were lignin, and molasses rich in hemicellulose-derived oligomers. The optimization of the process led to the following results at a steam explosion severity of log 10 (R 0 ) = 3.80: viscose-grade cellulose pulp yield = 70% of the potential; lignin recovery = 70% of the Klason lignin present in the original straw; hemicellulose sugars = 55% of the potential pentosan, recovered as molasses. The production of chemical pulp from wheat straw was studied using a conventional soda process and a two-stage cooking sequence, consisting of straw impregnation with the caustic liquor followed by rapid (4 min) steam explosion treatment (160±2158C) of the impregnated material following withdrawal of the excess impregnation liquor. The impregnation/steam treatment sequence for wheat straw pulping shortens the total processing time (impregnation + cooking) to less than 15 min. Unbleached IRSP pulps, with yields of 33±34% (screened and ®nes removed) show strength properties comparable both to those of conventional unbleached wheat straw soda pulps and hardwood Kraft pulps, re®ned to similar freeness values (around 300 ml CSF). #
Pulp and fiber characterization of wheat straw and eucalyptus pulps–A comparison
The response to refining of wheat straw and eucalyptus pulps as well as the relationships between refining, fiber properties, and paper properties are described in this paper. Pulps were bleached applying different bleaching sequences and thereafter refined to varying degrees. Pulp and fiber properties were investigated and set into relation to the final sheet properties. The results show that wheat straw pulps respond to refining more easily than eucalyptus pulps and that the differences are due mainly to morphological and ultrastructural differences as well as fines content and xylan content. The development of strength properties of the different pulps was found to be strongly correlated to the number of dislocations, i.e. weak points in the fiber wall, as well as to the morphological appearance of the pulp fibers after refining. A higher initial number and a faster development of dislocations together with the creation of large amounts of fines explain the slower and lower development of strength properties of wheat straw pulps than of eucalyptus pulps. Removal of fines from wheat straw pulps improved not only the drainability of the pulp suspension but also the mechanical and optical sheet properties. This indicates that the fines in the wheat straw pulps act mainly as filler with low bonding properties. The fact that fractionated D(EOP)D wheat straw pulps can deliver good mechanical sheet properties at very good drainability with no or only minor refining is very interesting when evaluating the potential of replacing or partially replacing eucalyptus with domestic Chinese raw materials in furnishes for production of different paper products.
Influence of process variables on the properties of pulp obtained by ethanol pulping of wheat straw
Process Biochemistry, 1999
The influence of independent variables in the cooking of wheat straw with ethanol-water mixtures (ethanol concentration, cooking time and temperature) on various properties of the pulp (yield and holocellulose, h-cellulose and lignin contents) was studied with a view to determining the best operating conditions to obtain quality pulp (pulp with high holocellulose and h-cellulose contents and a low lignin content). The results were fitted to a second-order polynomial function using a BMDP system package and a 2 m central composite design. In this way, equations that reproduce yield and the holocellulose and h-cellulose contents with errors less than 3.5% and lignin content with errors less than 15% were derived. Additional equations were obtained that relate dependent variables to the treatment severity parameter, R o and reproduce the experimental yields and holocellulose, h-cellulose and lignin contents with errors less than 10, 4, 4 and 15%, respectively. Obtaining pulp with high holocellulose and h-cellulose contents and a low lignin content, entails using a high temperature (190°C) and ethanol concentration (80%) for a long time period (2 h).
Comparison of molded pulps from rice straw, pineapple leaf and banana stem pulps
ScienceAsia
Molded pulp is an eco-friendly packaging product popularly chosen nowadays. It is mostly used to replace plastic containers such as polypropylene (PP), polystyrene (PS) and polyethylene (PE). Besides, the non-wood pulps from agricultural crops and residues have been increasingly studied as alternative materials in pulp production. Therefore, this study aimed to investigate the possibility of utilizing rice straw (R), pineapple leaf (P) and banana stem (B) as raw materials to prepare pulps by using a soda-anthraquinone (AQ) pulping process. The pulping was carried out with 4-7% sodium hydroxide solution and 0.1% AQ, a liquid-solid ratio of 10:1, and pulping time of 15-30 min at 98 ± 2°C. Next, the obtained pulps unscreened (u-) were sieved into screened (s-) portions, and the molded sheets from both u-and s-portions were formed using compression molding technique under pressure of 0.6 MPa at 130°C for 5 min. The molded sheets from R pulp showed higher tensile strength and tensile index (62 MPa and 63.28 Nm/g, respectively) when compared to the sheets from P and B pulps. From SEM images, the cross-sections of the R pulp sheets revealed less voids between fiber layers and, hence, better fiber-packing and bonding. Based on their mechanical properties compared to commercial molded pulp products, it suggested that these agricultural residues and their pulps can be considered promising alternative sources for pulp and molded pulp production.
Feasibility of rice straw as a raw material for the production of soda cellulose pulp
Journal of Cleaner Production, 2010
The main objective of this work is to evaluate the suitability of rice straw and sodaeanthraquinone (sodaeAQ) pulping process to produce pulp and paper. To reach this aim, it was used a central composite factorial design to study the influence of operational variables (temperature (155e185 C), cooking time (30e90 min), soda concentration (10e20%), anthraquinone concentration (0e1%) and liquid/solid ratio (6e8)), in sodaeanthraquinone cooking of rice straw on pulps and paper sheets properties obtained.
Strength Characteristics of Chemi-Mechanical Pulp from Rapeseed Straw
2014
The objective of this work was to determine the potential application of rapeseed straw in the chemi-mechanical pulping process. Stalks of rapeseed straw (species Brassica napus L. convar. napus) were used for the pulping process. The chemi-mechanical pulping comprises four main operations, viz. chipping, grinding, leaching, and beating. For chemi-mechanical pulps, the influence of caustic soda charge applied in the leaching process upon the bending stiffness and bending modulus of elasticity in the region of reversible deformation was investigated by using a three-point loading method. The preliminary results revealed that the bending modulus of elasticity increases with increasing caustic soda charge from 0.22 to 1.11 kNmm −2 for both basis weights of the handsheets (approx. 260 gm −2 and 520 gm −2 ). Similarly, the bending stiffness of handsheets having lower basis weight slightly increases with increasing alkaline charge, whereas, for higher basis weight, the effect of alkali...
Chemi-Mechanical Pulp from Rapeseed Straw
2016
This study deals with chemi-mechanical pulping of rapeseed straw (species Brassica napus L. convar. napus). Three cold chemi-mechanical processes, namely neutral sulphite, alkaline sulphite, and caustic soda, were applied under laboratory conditions. The chemi-mechanical pulping comprises four main operations, viz. chipping, grinding, leaching, and beating. The influence of varying charges of chemicals on the total yield, strength properties, such as bending stiffness, bending modulus of elasticity, curvature in the region of elastic and plastic deformation, as well as the tensile index of pulp handsheets, was determined. The results obtained revealed that the cold caustic soda pulping has a greater effect on the bending stiffness and bending modulus of chemi-mechanical pulps in comparison with neutral sulphite and alkaline sulphite pulping, although the total pulp yield for caustic soda pulping was lower than that for neutral sulphite and alkaline sulphite pulping. For all three co...
Feasibility of Utilizing Corn Stalk Residues in Chemi- Mechanical Pulping (CMP) and Papermaking
Journal of Chemical Research
When paper making was invented, non-wood fibers were utilized as the main source of the raw material and the first major paper mill in North America used wheat straw [1]. However, this situation did not last too long and very soon, wood fibers replaced non-wood fibers. However, not all countries in the world possess suitable and sufficient quantities of wood to fulfill their fiber requirements . Consequently, these countries are forced to use non-wood fibers and research on this aspect of pulping was foreseen and most efforts were concentrated on this issue . Even though, the share of non-wood pulping is only 6.5% of the total pulp production, there
Comparison of the properties of chemical cellulose pulps
Cellulose, 1994
The literature related to differences between chemical cellulose pulps produced by different pulping processes has been reviewed. Kraft pulps tend to be stronger, particularly in tear strength, while sulfite pulps hydrate and beat more readily. Organosolv pulps tend to mirror the properties of sulfite more than those of kraft pulps. A number of theories have been offered to explain the different properties of the chemical pulps; however, none has been universally accepted. It may be that acidic processes develop weak points in the fibers which are magnified in tear strength losses since, at a constant tensile strength, a 10% loss in fiber strength can lead to a 25-30% loss in tear strength. The effects of acidic pulping may also be magnified in greater fiber breakage and damage in the subsequent refining stages. However, strength improvements for inferior pulps can be realized through post-chemical treatments. Caustic treatments appear to give the greatest improvements, presumably due to increases in acidic group content which results in enhanced swelling properties, and possible subtle reorientation of cell wall polymers. The strength of hornified, recycled fibers can also be enhanced with such treatments, although simple beating will restore considerable strength, but at the expense of drainage rates. It is clear that the processes are complex and involve both the chemistry and physics of the fibers and how these attributes combine to affect the subsequent beating of the fibers for bonding and strength development.
Physicochemical and thermal characteristics of sugarcane straw and its cellulignin
Journal of The Brazilian Society of Mechanical Sciences and Engineering, 2018
Combustion of biomass is considered to be a source of atmospheric pollution and, therefore, is one of the important sources of CO 2 emission. This paper discusses the burning of sugarcane straw and its cellulignin in laboratory tests to determine the characteristics and emission factors, of this combustion process. Elemental, chemical composition and thermogravimetric analyses were performed for both samples. Carbon contents for sugarcane straw and its cellulignin were estimated, and the values found were 45.69% and 44.28%, respectively. Higher heating values (HHV) were determined by experimental methods with a calorimetric bomb and were estimated by theoretical equations. The best results were obtained when only the lignin's content was considered. During the experimental tests to determine HHVs, cellulignin did not burn completely, while straw burned completely. This could be because cellulignin contains more ashes, resulting in more residual ash after burning. Pollutant emission of CO 2 , CO, NO and UHC was evaluated in the flaming and smoldering combustion phases. NO concentrations were not presented because they were less than 10 ppm. The average theoretical and experimental emission factors for CO 2 were analyzed. CO 2 emissions factors found for sugarcane straw and their cellulignin were 1316 ± 83.6 and 1275 ± 105 g kg-1 of dry burned biomass, respectively. The evaluated parameters are useful to incorporate these materials into a future biorefinery.