Dimensionless parameter approach for oxygen delignification kinetics

Dogan, Ismail
Gueruez, Gueniz
In this study, the kinetic analysis of oxygen delignification of Turkish southern hardwood Kraft pulp was carried out. The kinetic rate data were collected in a high pressure batch reactor at industrially significant conditions of temperature, alkali charge, and oxygen partial pressure. The mass transfer effects were examined for the system studied. After eliminating the mass transfer resistances in the delignification system, the kinetics of oxygen delignification was studied and the governing rate equations were derived. The kinetics of the carbohydrate degradation was analyzed to determine the extent of delignification without the reduction in the pulp strength below the acceptable level; which is usually taken as the removal of no more than half of the lignin in the pulp entering the oxygen stage. The kappa number, intrinsic viscosity, and reaction time were expressed in dimensionless forms to generalize the results and to make them independent of the initial values, experimental conditions, and pulping conditions prior to oxygen delignification. These dimensionless parameters were fitted to nonlinear equations. These equations can also be used for the control of the oxygen delignification towers. The same approach was also used for the reported studies in the literature which allowed the comparison with the results of this study.


Mass transfer and kinetics in oxygen delignification
Doğan, İsmail; Yücel, Hayrettin; Department of Chemical Engineering (2005)
In this study, the kinetic analysis of oxygen delignification of Turkish southern hardwood Kraft pulp was carried out. Kraft pulp was obtained from Mopak Dalaman pulp and paper mill. The kinetic rate data were collected in a 1 L high pressure batch reactor. The delignification experiments were carried out under a wide range of industrially significant conditions of temperature (90, 100 and 110 oC), alkali charge (1, 3, 5% on oven dry pulp), and oxygen partial pressure (0.5, 3.5, 6.5 bar). In order to achiev...
Use of biodiesel byproduct crude glycerol as the carbon source for fermentation processes by recombinant Pichia pastoris
Celik, Eda; Ozbay, Nalan; OKTAR, NURAY; Çalık, Pınar (American Chemical Society (ACS), 2008-05-07)
The aim of this study is to investigate the efficiency of using crude glycerol, the main byproduct of biodiesel industry, directly in the production media of Pichia pastoris fermentation processes. Different biodiesel synthesis conditions were examined, that is, transesterifications of canola, corn, soybean, and sunflower oils, with pure methanol in a molar ratio of 1:6 or 1:3, using 1% or 0.5% (w/v) NaOH as the catalyst. Among these, canola oil-derived glycerol served as the most favorable carbon source, a...
Effects of Zinc Borate on the Flame Retardancy Performance of Aluminum Diethylphosphinate in Polyamide-6 and its Composites
Polat, Özlem; Kaynak, Cevdet (Carl Hanser Verlag, 2019-03-01)
In this study, the flame retardancy contribution of zinc borate when used together with a traditional flame retardant (aluminum diethylphosphinate compound) was investigated for neat polyamide-6 and for 15 wt% short glass fiber reinforced composite. Melt mixing with twin-screw extrusion was the compounding method while injection and compression molding were the shaping methods of specimens. Three different flammability tests (limiting oxygen index, UL-94 vertical burning, mass loss calorimetry) indicated th...
Effect of dispersed phase feed time on the droplet size of Pickering emulsions produced in a stirred tank
Donmez, Dila; Ayrancı Tansık, İnci (Wiley, 2020-06-01)
The aim of this study was to investigate the effect of feed time of the oil phase on the average droplet size of Pickering emulsions produced in stirred tanks. Three types of impellers were tested: RT, up-pumping PBT (PBTU), and down-pumping PBT (PBTD). All the impellers were tested at two sizes, T/3 and T/2. All configurations were compared at constant tip speed, power per mass, and impeller Reynolds number. The droplet diameters were measured in Mastersizer (R) 3,000 (Malvern). The results showed that an ...
BALCI, S; Doğu, Timur; YUCEL, H (American Chemical Society (ACS), 1993-11-01)
Pyrolysis kinetics of almond and hazelnut shells and beech wood were carried out using a thermogravimetric technique. Experiments were repeated for different final pyrolysis temperatures ranging from 300 to 850-degrees-C. Approximately 90% of the pyrolysis reactions were completed up to 450-degrees-C. The initial values of the activation energy of pyrolysis reaction were found to be around 22 kcal/mol for shells of almond and hazelnut. On the other hand, initial activation energy of beech wood pyrolysis was...
Citation Formats
I. Dogan and G. Gueruez, “Dimensionless parameter approach for oxygen delignification kinetics,” INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, pp. 5871–5878, 2008, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/65998.