scholarly journals Kinetics of sulfur dioxide-alcohol-water (SAW) pulping of sugarcane straw (SCS)

TAPPI Journal ◽  
2017 ◽  
Vol 16 (06) ◽  
pp. 313-328 ◽  
Author(s):  
ASIF MASIH SHARAZI ◽  
ADRIAAN VAN HEININGEN
Keyword(s):  
Sulfur Dioxide ◽  
Lignin Content ◽  
Cellulose Hydrolysis ◽  
Solvent System ◽  
Kappa Number ◽  
Hydrolysis Rate ◽  
Sugarcane Straw ◽  
Linear Relationships ◽  
Alcohol Water ◽  
Kinetics Of

Pulping kinetics of sugarcane straw (SCS) using the sulfur dioxide (SO2)-alcohol-water (SAW) system were investigated with different solvents (methanol, ethanol, and isopropanol) in order to evaluate the effect of the solvents. The methanol, ethanol, and isopropanol SAW pulps are identified as SMW, SEW, and SPW, respectively. The pulping experiments were carried out at 135°C, 145°C, and 155°C with cooking liquor (L/F = 4 L/kg feedstock) composition; SO2/alcohol/water of 12/44/44 w%. The pulps were characterized in terms of yield, kappa number, viscosity, cellulose, and hemicellulose and lignin content. After a fast initial dissolution phase, two regimes of delignification were identified in all solvent systems: a bulk and a residual phase. Bulk delignification and xylan removal followed first order kinetics in residual lignin and xylan, respectively, while the cellulose hydrolysis rate was zeroth order in cellulose. Linear relationships between Klason lignin content and kappa number were developed for each solvent system after correcting the acid insoluble lignin for ash and non-oxidizable matter. The corrected lignin content on original SCS was used to develop the bulk delignification kinetics. Rate constants and activation energies for bulk delignification, xylan removal, and cellulose hydrolysis were evaluated for each pulping system. In terms of degree of delignification, the pulping systems followed the sequence of: SMW <SEW <SPW. Bleachable grade pulps with acceptable intrinsic viscosity (>800 ml/g) were produced in SEW and SPW systems, while the lower rate of delignification and higher rate of cellulose hydrolysis in SMW yielded much lower viscosity pulps of higher kappa number at the same pulping temperature and time. The results are explained in terms of the effective acidity and lignin/carbohydrate dissolution properties of the pulping liquors.

Sugarcane straw lignin obtained by sulfur dioxide-alcohol-water (SAW) fractionation: Effect of solvent

2018 ◽  
Vol 115 ◽  
pp. 235-242 ◽  
Author(s):  
Asif M. Sharazi ◽  
Adriaan R.P. van Heiningen ◽  
Ivan Sumerskii ◽  
Markus Bacher
Keyword(s):  
Sulfur Dioxide ◽  
Effect Of Solvent ◽  
Sugarcane Straw ◽  
Alcohol Water ◽  
Fractionation Effect

Does the kappa number method accurately reflect lignin content in nonwood pulps?

TAPPI Journal ◽  
2018 ◽  
Vol 17 (11) ◽  
pp. 611-617
Author(s):  
Sabrina Burkhardt
Keyword(s):  
Lignin Content ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Original Data ◽  
Kappa Number ◽  
Klason Lignin ◽  
Organic Functional Groups ◽  
Pulp Properties ◽  
Wood Pulps ◽  
Hexenuronic Acid

The traditional kappa number method was developed in 1960 as a way to more quickly determine the level of lignin remaining in a completed or in-progress pulp. A significantly faster approach than the Klason lignin procedure, the kappa number method is based on the reaction of a strong oxidizing agent (KMnO4) with lignin and small amounts of other organic functional groups present in the pulp, such as hexenuronic acid. While the usefulness of the kappa number for providing information about bleaching requirements and pulp properties has arguably transformed the pulp and paper industry, it has been mostly developed for kraft, sulfite, and soda wood pulps. Nonwood species have a different chemical makeup than hardwood or softwood sources. These chemical differ-ences can influence kappa and Klason measurements on the pulp and lead to wide ranges of error. Both original data from Sustainable Fiber Technologies’ sulfur and chlorine-free pulping process and kappa and Klason data from various nonwood pulp literature sources will be presented to challenge the assumption that the kappa number accurately represents lignin content in nonwood pulps.

The Reactivity of Different Active Forms of Sodium Carbonate with Respect to Sulfur Dioxide

1992 ◽  
Vol 57 (11) ◽  
pp. 2302-2308
Author(s):  
Karel Mocek ◽  
Erich Lippert ◽  
Emerich Erdös
Keyword(s):  
Thermal Decomposition ◽  
Liquid Phase ◽  
Sulfur Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Sodium Carbonate ◽  
Room Temperature ◽  
Active Form ◽  
The Other ◽  
Kinetics Of

The kinetics of the reaction of solid sodium carbonate with sulfur dioxide depends on the microstructure of the solid, which in turn is affected by the way and conditions of its preparation. The active form, analogous to that obtained by thermal decomposition of NaHCO3, emerges from the dehydration of Na2CO3 . 10 H2O in a vacuum or its weathering in air at room temperature. The two active forms are porous and have approximately the same specific surface area. Partial hydration of the active Na2CO3 in air at room temperature followed by thermal dehydration does not bring about a significant decrease in reactivity. On the other hand, if the preparation of anhydrous Na2CO3 involves, partly or completely, the liquid phase, the reactivity of the product is substantially lower.

Deep eutectic solvent delignification: Impact of initial lignin

BioResources ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 7301-7310
Author(s):  
Veronika Majová ◽  
Silvia Horanová ◽  
Andrea Škulcová ◽  
Jozef Šima ◽  
Michal Jablonský
Keyword(s):  
Lactic Acid ◽  
Oxalic Acid ◽  
Lignin Content ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Deep Eutectic Solvents ◽  
Kappa Number ◽  
Kraft Pulps ◽  
Oxygen Delignification ◽  
Detailed Understanding

This study aimed to resolve the issue of the lack of detailed understanding of the effect of initial lignin content in hardwood kraft pulps on pulp delignification by deep eutectic solvents. The authors used Kappa number of the concerned pulp, intrinsic viscosity, and selectivity and efficiency of delignification as the parameters of the effect. The pulp (50 g oven dry pulp) was treated with four different DESs systems based on choline chloride with lactic acid (1:9), oxalic acid (1:1), malic acid (1:1), and system alanine:lactic acid (1:9); the results were compared to those reached by oxygen delignification. The results showed that the pulp with a higher initial lignin content had a greater fraction of easily removed lignin fragments.

scholarly journals Kinetics of Enzymatic Hydrolysis of Southeast Sulawesi Sago Starch

2020 ◽  
pp. 53-61
Author(s):  
Ansharullah Ansharullah ◽  
Muhammad Natsir
Keyword(s):  
Enzymatic Hydrolysis ◽  
Maximum Velocity ◽  
Enzyme Concentration ◽  
Hydrolysis Rate ◽  
Sago Starch ◽  
Optimum Conditions ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Substrate Concentrations ◽  
Menten Constant

The aims of this study were to characterize the kinetics of enzymatic hydrolysis of sago starch, obtained from Southeast Sulawesi Indonesia. The enzyme used for hydrolysis was bacterial ∝-amylase (Termamyl 120L from Bacillus licheniformis, E. C. 3.2.1.1).  The method to determine the initial velocity (Vo) of the hydrolysis was developed by differentiation a nonlinear equation (NLE).  The Vo of the hydrolysis was measured at various pH (6.0, 6.5,and 7.0), temperatures (40, 60, 75 and 95oC), enzyme concentrations (0.5, 1.0, 1.5 and 2.0 µg per mL) and in the presence of 70 ppm Ca++. The optimum conditions of this experiment were found to be at pH 6.5 – 7.0 and 75oC, and the Vo increased with increasing enzyme concentration. The Vo values at various substrate concentrations were also determined, which were then used to calculate the enzymes kinetics constant of the hydrolysis, including Michaelis-Menten constant (Km) and maximum velocity (Vmax) using a Hanes plot.  Km and Vmax values were found to be higher in the measurement at pH 7.0 and 75oC. The Km values  at four  different combinations of pH and temperatures (pH 6.5, 40oC; pH 6.5, 75oC; pH 7.0, 40oC; pH 7.0, 75oC) were found to be 0.86, 3.23, 0.77 and 3.83 mg/mL, respectively; and Vmax values were 17.5, 54.3, 20.3 and 57.1 µg/mL/min, respectively. The results obtained showed that hydrolysis rate of this starch was somewhat low.

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