Sequential batch reactor for eucalypt kraft pulp effluent treatment with Trametes versicolor

BACKGROUND: A sequential batch reactor (SBR) was used for eucalypt kraft pulp effluent treatment with Trametes versicolor. A 2³ full factorial design and response surface methodology were applied to optimise the batch fermentation conditions. Effluent concentration, culture medium and inoculum age were the factors selected for this study in order to optimise the reduction of chemical oxygen demand (COD). RESULTS: The presence of Trametes Defined Medium (TDM) in the fermentation was required to obtain a significant COD reduction. Experiments in the batch reactor confirmed, in general, the predicted results of optimisation developed from Erlenmeyer batch assays. The T. versicolor culture remained active during 42 days of study in the SBR, providing approximately 80% of COD reduction. CONCLUSION: Trametes versicolor may be considered as very promising for the biological treatment of effluents from kraft pulp mills in an SBR system instead of the activated sludge mixed cultures traditionally used. Copyright © 2008 Society of Chemical Industry     

Enzymatic Browning in Apple Pulps

Enzymatic browning in Golden Delicious apple pulp was studied as related to degree of ripeness and temperature (3.5–31°C). Green apple pulp showed the highest rate of browning. This was attributable to differences in ascorbic acid (AA) content and polyphenoloxidase activity in young fruits. The rate of browning determined by CIE L* measurements followed complex temperature dependent kinetics, represented by a multiple linear effects with log time. Equal changes in L* parameter yielded straight lines in a log temperature vs log time plot. Inhibition with AA caused an initial slow rate of browning and a well defined break point associated with exhaustion of antioxidant properties of the AA. The greater the AA concentration the longer the initial period.     

Delta4型外流式压力筛的长纤维浆筛选实践

介绍了Delta4型压力筛生产全漂白硫酸盐法马尾松浆的运行情况，对存在的问题进行分析探讨，并对比了技改重新选型后的生产情况。     

常用浆种在纤维中底板抄造中的应用分析

本文介绍了常用几种浆板在纤维中底板中的应用。     

Conductive Papers Containing Metallized Polyester Fibers for Electromagnetic Interference Shielding

Conductive papers were developed for preventing or reducing electromagnetic interference (EMI), and their shielding efficiency was evaluated. This type of conductive paper consists of wood pulp, synthetic pulp and metallized polyester fibers (0.5–2.0 mm long and 14 m in diameter) whose surfaces are coated with nickel alone (Ni-PET) or copper and nickel double layers (Ni-Cu-PET) by electroless plating. In this report, the effect of the characteristics of these metallized fibers, such as their conductivity, geometry and the concentration of fibers in paper, which lead to high efficiency for shielding effectiveness is discussed. For instance, one of the conductive papers (80 g/m2) which was prepared by mixing 40% Ni-Cu-PET and 60% synthetic polyethylene pulp showed over 40 dB shielding effectiveness between 10 MHz and 1 GHz.     

Method for characterization of triacylglycerols and fat-soluble vitamins in edible oils and fats by supercritical fluid chromatography

This study demonstrates the usefulness of capillary supercritical fluid chromatography (SFC) for the characterization of triacylglycerols of edible oils and fats. Triacylglycerols were separated according to the acyl carbon number and the degree of unsaturation on a 25% cyanopropyl/25% phenyl/50% methylpolysiloxane stationary phase. Valuable information concerning the triacylglycerol composition of berry oils was obtained, despite the overlapping of certain triacylglycerol peaks. Simultaneous analysis of fat-soluble vitamins and triacylglycerols is not practical by capillary SFC with flame-ionization detection because of the low concentration of naturally-occurring fat-soluble vitamins in edible oils. Therefore, higher loading of the sample, which led to overloading of triacylglycerols, was required to get reasonable peaks for fat-soluble vitamins. The method was applied to the characterization of triacylglycerols and tocopherols in sea buckthorn pulp and seed oil, and cloudberry seed oil without any sample purification prior to SFC. In addition, the stationary phase proved useful for separating the more complex mixtures of triacylglycerols found in milk fat and in fish oil.     

NMR imaging and differential scanning calorimetry study on drying of pine,birch, and reed pulps and their mixtures

Drying, water fractions, and water distribution were investigated for pine, birch, and reed pulps and pine–birch, pine–reed, and pine–birch–reed pulp mixtures. Gravimetrically determined drying times showed that the drying rates of the pulps decreased at two to four inflection points. Characterizations of the dried pulps by differential scanning calorimetry (DSC) showed a faster removal of free water than freezing and nonfreezing bound waters; all decreased simultaneously, however. DSC also revealed the critical water contents at which the free water and freezing bound water disappeared. The gravimetrically determined inflection points of the drying curves corresponded with the critical points determined by DSC. NMR line widths and images produced by ¹H‐NMR imaging revealed the nature and regions of the pulp drying. The constant growth rate of the NMR line widths with decreasing water content appeared to change at two inflection points, which fell approximately in the same water content regions as the inflection points of the drying curves. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 937–945, 2006     

制浆造纸工业用消泡剂的开发及应用进展

制浆造纸工业生产过程中不可避免会产生泡沫,泡沫控制不当会严重影响制浆造纸工艺条件的执行以及设备的正常运转,导致产品产量和质量降低,而控制泡沫最直接有效的措施是添加合适的消泡剂.该文介绍了制浆造纸工业生产中泡沫的产生和稳定机理,泡沫对制浆造纸工业生产过程和产品质量的影响,并针对制浆造纸生产中制浆、抄纸、涂布和脱墨等工段泡沫特性和消泡要求,综述了制浆造纸用消泡剂的发展历程、各工段消泡剂种类和性质,介绍了消泡剂的研制开发和实际应用成本及使用效果等,并对制浆造纸用消泡剂的发展进行了展望.     

Liquid spouting of pulp fibers in a conical vessel

Pulp fibers can be spouted in water in a conical vessel. The entities which are spouted are fiber flocs rather than individual fibers. Synthetic fibers, which do not flocculate, cannot be spouted. For comparison, rigid spherical particles were spouted with water in the same conical vessel. Liquid spouting of rigid particles was similar to gaseous spouting. For pulp spouting, the minimum spouting velocity is proportional to the mass of fibers in the bed and inversely proportional to the diameter of the inlet. For rigid particles, the minimum spouting velocity is proportional to the height of the bed and inversely proportional to the square of the diameter of the inlet. A model for the minimum spouting velocity was developed for pulp spouting.     

Diffusion of lignin macromolecules within the fibre walls of kraft pulp. Part I: Determination of the diffusion coefficient under alkaline conditions

The intrinsic rate of diffusion of soluble lignin from fibre walls to bulk liquor has never been determined previously because of experimental difficulties; for example, the diffusion rate determined in a stirred cell is affected by the mechanical action of stirring. In our work, the intrinsic rate of diffusion of lignin macromolecules from the fibre walls of a softwood kraft pulp was determined under alkaline conditions using a displacement cell which eliminated external heat and mass transfer resistances and pulp fibre disturbances. The effects of such experimental conditions as pulp bed height and liquid flow rate were studied. The diffusion rate can be described by a diffusion model for a hollow cylinder with a very wide range of diffusion coefficients. The diffusion rate increased with increasing pH. Our results provide a new understanding of the lignin diffusion process in fibre walls, which is affected by the size of lignin molecules and the pores, and by the electrostatic interactions between intrafibre pore walls and lignin.