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.

Effect of operating variables on the scrubbing efficiency of SO2 in a spray drier was investigated using trona (Na2 CO3 · NaHCO3 · 2H2 O) solutions of different compositions. Results indicated that for a Na/S mole ratio of two (stoichiometric ratio) about 80% of the SO2 was removed. For higher Na/S ratios, SO2 removal efficiency increased by up to 100%. Increased SO2 concentration in the feed gas and decreased outlet temperature caused an increase in the overall conversion. At low temperatures and low SO2 concentration, the reaction takes place mainly between SO2 and Na2 CO3 As the temperature is increased, decomposition of NaHCO3 to Na2 CO3 and sorption reactions take place simultaneously.

No abstract

No abstract

No abstract