Mass transfer and thermodynamic aspects of sodium desorption from eucalyptus kraft pulp by acidification using carbon dioxide

作者：Vitasari Denny^*; Nguyen Kien L; Dang Vinh

来源：Chemical Engineering Journal, 2009, 151(1-3): 302-307.

DOI：10.1016/j.cej.2009.03.008

• Pulp acidification
• Desorption
• Carbon dioxide
• Eucalyptus
• Kraft pulp

The thermodynamics and mass transfer aspects associated with the use of CO(2) for the acidification, particularly for the removal of Na( ) from pulp fibres, were studied. The acidifications with CO(2) and with H(2)SO(4) were carried out in a stirred tank reactor under different temperatures, agitation speeds, concentrations of CO(2) and H(2)SO(4) and treatment times. The CO(2) acidification of pulp was found to be very fast at Re > 10(4) and N(p) of 4, and reached equilibrium within 5 min. The volumetric mass transfer coefficient, k(L)a, of the CO(2) acidification was found to be in the range of 0.0005-0.0083 s(-1). Thermodynamically, the CO(2) acidification was achievable only at pH > 4. The extent of the resultant Na( ) exchange increased with the acidification time, agitator speed and CO(2) flow rate. Under similar experimental conditions, the extent of Na( ) desorption by CO(2) acidification was found to be slightly lower than that achieved by sulfuric acidification. The equilibrium distribution of Na( ) in the solution and the fibre phase can be estimated using a model based on the Donnan theory.

• 出版日期2009-8-15