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Journal articles
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Open Access
Model development for real oxygen delignification processes, TAPPI Journal October 2024

ABSTRACT: Previous extensive work has been done on modeling the oxygen delignification process, based on how the basic parameters, i.e., temperature, kappa number, concentration of alkali, and concentration of oxygen, affect the delignification rate. However, these models are not used extensively to evaluate the performance of real processes, primarily because they have not been able to properly consider all the essential issues affecting delignification in practice. Such issues include the mass transfer and consumption of oxygen, which defines the concentration of dissolved oxygen in the process, and the effect of that concentration on the delignification rate. In this paper, a new way to model the oxygen delignification process is used in which these parameters, among other smaller matters, are taken into account. The basic model and its parameters were defined by the information obtained from the literature, delignification made in the laboratory tests, and mill processes and mill tests. An essential aspect of these studies was the information obtained from the oxygen concentration measured in the residual gas obtained from the top of the reactor. With the aid of this measurement, it was possible to define more accurately the consumption of oxygen and partial pressure of oxygen that define the concentration of dissolved oxygen in the reactor. Using mill experiments, a model was formed that predicts the operation of the oxygen delignification process. The model was used to show how much the process could be improved by optimizing the charge of the oxygen. The mill experiments also confirmed that mass transfer of oxygen is modeled correctly enough, except when the charge of oxygen is very low and/or the mixing is not efficient enough. In that case, there is variation in the concentration of oxygen in the process that should be taken into account in the modeling.

Journal articles
Open Access
Extraction of hardwood biomass using dilute alkali, TAPPI JOURNAL June 2012

Extraction of hardwood biomass using dilute alkali, TAPPI JOURNAL June 2012

Journal articles
Open Access
Influence of topcoat pigment particle size distribution on tail-edge pick resistance in sheet-fed offset printing, TAPPI JOURNAL June 2012

Influence of topcoat pigment particle size distribution on tail-edge pick resistance in sheet-fed offset printing, TAPPI JOURNAL June 2012

Journal articles
Open Access
The hyperbolic theory of light scattering, tensile strength, and density in paper, TAPPI JOURNAL November 2011

The hyperbolic theory of light scattering, tensile strength, and density in paper, TAPPI JOURNAL November 2011

Journal articles
Open Access
Imaging of ink jet penetration in uncoated paper using microscopic techniques, TAPPI JOURNAL November 2011

Imaging of ink jet penetration in uncoated paper using microscopic techniques, TAPPI JOURNAL November 2011

Journal articles
Open Access
Editor's Note: Peter Hart: A pulp and paper original, TAPPI JOURNAL October 2011

Editor's Note: Peter Hart: A pulp and paper original, TAPPI JOURNAL October 2011

Journal articles
Open Access
Comparison of test medium preparation methods for residual ink analysis, TAPPI JOURNAL October 2011

Comparison of test medium preparation methods for residual ink analysis, TAPPI JOURNAL October 2011

Journal articles
Open Access
Is deinkability of inkjet prints an issue?, TAPPI JOURNAL October 2011

Is deinkability of inkjet prints an issue?, TAPPI JOURNAL October 2011

Journal articles
Open Access
Pitch detackification with natural and modified talcs, TAPPI JOURNAL October 2011

Pitch detackification with natural and modified talcs, TAPPI JOURNAL October 2011

Journal articles
Open Access
Study of a model of cellulose depolymerization in the hypochlorite bleaching stage, TAPPI JOURNAL April 1988 88APR157

Study of a model of cellulose depolymerization in the hypochlorite bleaching stage, TAPPI JOURNAL April 1988

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