Browsing by Author "Kirci H."

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Comparison of pulping and bleaching behaviors of some agricultural residues
(2014-01-01) Ateş S.; Deniz İ.; Kirci H.; Atik C.; Okan O.T.
The present study determines the characteristics of bleaching and beating of annual plants and agricultural waste, which constitute important raw material potential for the pulp and paper industry in Turkey. It also examines the effects of this process on several paper properties. Firstly, chemical contents are determined for each raw material and then evaluated for use in the pulp and paper industry. All raw materials studied are found to be suitable for use in the pulp and paper industry, according to the determined chemical content. Secondly, pulp with different properties is obtained and subsequently pretreated with the enzyme xylanase. It is then bleached using the elementary chlorine-free (ECF) method, utilizing the DEpD bleaching sequence, which is both easy to apply and highly effective. The bleaching behavior of each material is then determined. The highest ISO brightness value of 98.3% is obtained using soda-AQ pulps deriving from rye straw. This is followed by wheat straw (92.0%), reed (88.6%), corn stalks (87.6%), and rice straw (87.5%). Each unbleached pulp sample is beaten at a constant 3000 revolutions PFI (9000 rev. for hemp), and changes in freeness properties are determined. The hardest material to beat is hemp fibers, followed by reed, rye, corn, and cotton stalks. The best beatable pulps are rice straw, tobacco, wheat, sunflower, and barley stalks. Paper sheets from both unbleached and bleached pulps are tested.
Influence of cooking variables of Crimean Pine (pinus nigra arnold SBSP. pallassiana) kraft pulp on the resulting paper Sheets
(2008-04-28) Ateş S.; Kirci H.; Tutus A.
A central composite factorial design was used to examine the influence of independent variables of kraft pulping of Crimean Pine wood chips at 50 Schopper-Riegler (oSR) level. Second order polynomial regression equations related each dependent variable to the different independent variables were obtained that reproduced the experimental results for the PFI beating revolutions, breaking length, burst index, tear index, stretch and brightness at 50 oSR obtained at sulphidity, H-factor and active alkali rates over the ranges 15-45%, 800-2400 and 14-22% respectively, with average errors less than %20. To minimize environmental effects of sulphide and acceptable levels of the properties of the paper sheets, low sulphidity rate, high H-factor and medium alkali concentration can be used.
Influence of pulping conditions on the properties of anatolian black pine (pinus nigra arnold ssp. Pallassiana) kraft pulps
(2007-01-01) Ateş S.; Kirci H.
Anatolian Black Pine wood chips were pulped using kraft method in laboratory scale batch digester. A series of experimental kraft pulping was carried out according to Central Composite Design (CCD) to investigate the pulping process and to study the effect of its variables (active alkali rate, sulphidity rate and Vroom's H-factor combining temperature and time) on pulp quality and yield. Second order polynomial regression equations using three independent process variables, were found to be approprite for describing kraft pulping of Anatolian Black Pine wood fibers. The derived equations were able to predict the kappa number, viscosity, yield, holocellulose and α-cellulose content of the pulp with adjusted R2 values of 96.1%, 96.8%, 86.3%, 62.5%, 96.1% and 92.2% respectively. H-factor level and the active alkali charge are the most strongly influcing all the dependent variables. In order to obtain acceptable levels of the pulp properties, high sulphidity rate (45%), medium H-factor (1600) and medium alkali concentration (18%) can be used in kraft pulping of Anatolian Black Pine woods. © 2007 Taylor and Francis Group, LLC.