Viscosity Of Black Liquor Research Articles

Low-temperature alkaline soaking coupled with circulating alkali-oxygen cooking: A novel method for whole utilization of bagasse

The addition of oxygen accelerates lignin dissolution and reduces the cooking temperature during alkali-oxygen cooking. However, hemicellulose could oxidized into furan and organic acids, leading to the increasing viscosity of black liquor and hemicellulose loss. To retain the hemicellulose and reduce the circulating black liquor viscosity, low-temperature alkaline soaking before alkali-oxygen cooking was implemented. Alkaline soaking extracted about 70 % of pentose and 62 % of lignin from the bagasse. Further mild alkali-oxygen cooking could gained the 43 % yield pulp with brightness above 50 %, and the viscosity of the circulating black liquor was lower than 0.1 Pa∙s after five time cyclic cooking. The results show that low-temperature alkaline soaking coupled with circulating alkali-oxygen cooking could effectively extracts hemicellulose from bagasse while producing clean pulp with low-viscosity circulating black liquor. This work presents a novel method for realizing total component utilization of bagasse.

Analisis Sifat Fisika dan Kimia Lignin Tandan Kosong Kelapa Sawit asal Desa Sape, Kabupaten Sanggau, Kalimantan Barat

Analysis of the physical and chemical properties of palm empty fruit bunches (EFB) lignin from Sape village in Sanggau, West Borneo has been done. This research was aimed to find extract and isolate the EFB lignin, to determine density, and viscosity of black liquor containing EFB lignin and to find the purity, moisture content and ash content of isolated EFB lignin. Black liquor was extracted by using reflux process and the lignin was isolated by using organosolv process. The result showed that the density and viscosity of the black liquor was 0.9658 g/mL and 1.4565 Ns/m2, respectively. The isolated lignin isolated has purity about 64.64% with moisture content about 3.07% and the ash content about 30.34%. The data from this analysis became the basis of utilization of lignin TKKS in some lignin-based industries. Key words: Analysis of physical and chemical properties, lignin, EFB DOI: http://dx.doi.org/10.15408/jkv.v2i1.3102

Study on the Dynamic Viscoelasticity of Bamboo Kraft Black Liquor

The dynamic viscoelasticity of bamboo kraft pulping black liquor under various temperatures (ranging from 50 to 80 °C) and solids concentrations (60 to 80 wt.%) was studied. Rotational rheometer analysis data indicated that the viscoelastic motion law with a high solids concentration in black liquor was in accordance with the Kelvin model, and black liquor with a medium concentration conformed to the Maxwell model. As a result, the temperature and solids concentration greatly influenced the dynamic viscoelasticity of bamboo kraft pulping black liquor. For instance, the modulus increased as the solids concentration increased, indicating that the viscous component of black liquor was prominent. For this reason, it was easier to soften the bamboo black liquor, providing a favorable condition for the pure viscosity of black liquor. Steady shear thinning was apparent during the frequency shear process. The dynamic viscosity, storage viscosity, and complex viscosity of the black liquor decreased as the shear frequency increased. The quantitative relationship between dynamic viscosity and angular frequency can be described using the Power Law model.

A novel method for the determination of black liquor viscosity by multiple headspace extraction gas chromatography

This work demonstrates a novel method for the determination of viscosity in the concentrated black liquors from pulp mill recovery process. The method is based on the kinetic release of methanol (a vapor tracer) to the headspace in a sample closed vial by a multiple headspace extraction gas chromatographic technique. Both theoretical and empirical models were proposed for establishing the correlation with the reference method. The results showed that the correlation using either of the models is excellent for the tested black liquor samples (at 110°C). The presented method is simple and practical and can be a valuable tool for black liquor viscosity related research and applications.

Centrifugal Pump-Based Predictive Models for Kraft Black Liquor Viscosity: An Artificial Neural Network Approach

Previous investigators have shown that the Newtonian viscosity of black liquor (BL), a byproduct of kraft pulping process, can be estimated online from the performance parameters of an installed centrifugal pump (CP). Unfortunately, the existing models from which such estimates can be obtained lack the necessary robustness for process control applications and/or would require a substantial amount of data for periodic updates. This study developed a generalized artificial neural network (ANN)-based model which directly accounts for the effect of aging on the pump performance (hence the model). Simulation results show that ANN predicts BL viscosity better than the existing linear models as the former gives accurate and robust predictions at all practical operating points of the pump. Moreover, the ANN model requires just a single data point for its periodic recalibration as the pump ages significantly. The methodologies presented here can easily be adapted for use in any process industry where Newtonian pro...

Viscosity models for New Zealand black liquor at low solids concentrations

AbstractAvailability of accurate models for prediction of the viscosity of black liquor (BL) from the chemical pulping of pine will facilitate its online monitoring and control and subsequently the optimisation of combustion in a recovery boiler. New Zealand (NZ) BL viscosity data are limited, and no predictive model is available. The viscosities of the NZ BL samples at solids concentrations (SCs) < 50% were obtained at temperature of 25–85 °C and shear rate up to ∼2000 s−1. The samples showed Newtonian behaviour. Existing models from the literature and a binomial model developed in this work were used to fit the viscosity data as a function of SC and temperature. Accuracies of these models were examined for both the log‐transformed and the untransformed viscosity data using coefficient of correlation (R) and maximum absolute relative error (MARE) (between the actual and predicted viscosities), respectively, as indices. Although the existing models fit NZ BL viscosity data well when they were log‐transformed, they performed poorly when not transformed. Conversely, the new binomial model gave accurate predictions with both the log‐transformed and untransformed viscosity data (R = 0.9997; MARE = 5.7%). It is concluded that at low SCs, the viscosity of Newtonian BL can be accurately predicted using the new binomial model. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.

Shear-thinning properties of non-wood kraft pulping waste liquor

The flow curves of Bagasse Kraft black liquor in a shear rate range of 10−1–103 s−1 were investigated by Rheometric RFSII rheometer. In addition, the power-law equation was utilized to fit these flow curves at different conditions. The results show that Bagasse black liquors are non-Newtonian fluids instead of Newtonian fluids at higher solids contents, and the viscosities of black liquor decrease about 2–3 orders of magnitude with the increase of the shear rates. The apparent viscosity and flow behavior of bagasse black liquor are also affected by its solids content, and the higher the solids content is, the more the shear-thinning bagasse black liquor fluid is.

Black Liquor Sheet Breakup Mechanisms and the Effect on Drop Size

Black liquor is a spent liquor of the pulp and paper industry. It is burned in kraft recovery boilers for chemical and energy recovery. The high dry solids content and viscosity of black liquor require a high spraying temperature this high spraying temperature changes the performance of the boiler. Kraft recovery boiler deposit formation, emissions and chemical recovery are strongly affected by the drop size, size distribution and velocity of the black liquor spray formed by a splashplate nozzle. Black liquor droplet formation of a splashplate nozzle is the subject of this study. The sheet breakup mechanism was studied with a system based on a video and image-analysis. The drop size of mill-scale nozzles was also measured with an image-analysis-system. Measurements were carried out in a test chamber. The sheet breakup mechanism and drop size tests were carried out both below and over the boiling point of black liquor. Special attention was paid to the effect of flashing on drop formation. Temperature increase normally decreases drop size. In the case when the wavy-sheet disintegration changes to perforated-sheet disintegration, the drop size increases. Spray velocity rises when the temperature is increased above the boiling point.

Controlled black liquor viscosity reduction through salting‐in

AbstractBlack liquor viscosity increases exponentially with solids content and therefore causes processing problems for the paper industry by being a limiting factor in the Kraft pulp process. This study investigates a new approach for achieving viscosity reduction by “salting‐in” black liquor through the addition of thiocyanate salts. These salts generally increase the solubility of the polymer constituents in black liquor, leading to a decrease in its viscosity. Several thiocyanate salts capable of reducing liquor viscosity by more than two orders of magnitude have been identified, with viscosity reduction greatest at high solids content. Salting‐in of black liquor depends on the cation paired with the thiocyanate anion, as well as on solution pH and temperature. Comparative studies reveal that GuSCN is the most effective viscosity‐reducing agent of the series examined and that lignin plays an important role in the viscosity behavior of both unmodified and salted‐in black liquor at high solids concentrations. These experimental findings are interpreted in terms of the underlying principles that describe salting‐in and how it affects aqueous solution structure.

Effect of Pulping Conditions and Black Liquor Composition on Newtonian Viscosity of High Solids Kraft Black Liquors

The influence of black liquor composition and solids concentrations on the Newtonian viscosity of slash pine black liquors over wide ranges of temperature (up to 140 °C) and solids concentrations (between 50% and 83% solids) has been studied. It was found that the zero shear rate viscosity of high solids black liquors depends strongly on the cooking conditions and/or black liquor composition. Not only is high solids viscosity affected by lignin molecular weight and lignin concentration in the liquor but other organic and inorganic constituents of black liquor also make a significant contribution to viscosity. The dependency of zero shear rate viscosity on solids concentrations, and temperature is defined. The Newtonian viscosities vary over a wide range depending on temperature, solids concentrations and solids composition. The results indicate that, at fixed levels of effective alkali and sulfidity, the zero shear rate viscosities can be described as a function of both lignin concentration and lignin molecular weight. The viscosity of black liquor is an increasing function of the organics-to-inorganics ratio and is a decreasing function of the concentration of sodium and chloride ions and pH of the liquor.

Lowering Kraft Black Liquor Viscosity by Ultrafiltration

Abstract High viscosity is a major factor limiting the percentage total dissolved solids (%TDS) to which kraft black liquor (KBL), a spent pulping liquor, can be concentrated before it is burned to recover its fuel value and its inorganic chemicals. The effect on black liquor viscosity of removing high molecular weight lignin by ultrafiltration of 16% and 24% TDS liquors was studied. Viscosities of ultrafiltration permeates were reduced relative to feed black liquors. When a permeate was concentrated to higher %TDS levels, its viscosity decreased yet further relative to feed samples evaporated to similar solids levels. Retentate viscosity was very high relative to both feed and permeate. Ultrafiltration was carried out at 75[ddot]C using polysulfone membranes in a plate-and-frame or hollow fiber system. Flux rates varied greatly depending upon the specific liquor used. Flux was enhanced by increased temperature and increased linear velocity. The membrane molecular weight cutoff (MWCO) typically used was 5...

漂白廃液の回収とその影響 ＩＩＩ 漂白廃液の回収に伴う薬品回収工程への影響

Some effects associated with recovery of bleachery effluent to chemical recovery process were investigated. In oxidation process, little effect was observed on oxidation of sodium sulfide and methyl mercaptan by pH decrease of black liquor. But sulfide oxidation was slightly accelerated by some organics in bleachery effluent at low concentration of sodium sulfide. In evaporation process, the release of hydrogen sulfide was affected by the mixing of bleachery effluent, but release of methyl mercaptan was independent. Slight increase of black liquor viscosity during evaporation and precipitation from black liquor were observed by recovery of bleachery effluent. These changes depended on pH decrease or organics contained in bleachery effluent. But swelling volume of black liquor changed little. From these results, it seemed to be feasible to recover the neutralized bleachery effluent with alkali to chemical recovery process.

Thermal stability of kraft black liquor viscosity at elevated temperatures

Thermal stability of kraft black liquor viscosity at elevated temperatures