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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
Magazine articles
Utilization of palm fiber as papermaking materials: Microscopic structure and chemical pulping, TAPPI Journal October 2022
ABSTRACT: The microscopic structure and pulping properties of palm fiber were explored. Soda cooking and sulfate cooking were conducted and compared in terms of physical strength of the obtained pulps. Sulfate pulp showed better performance than soda pulp, as indicated by the 23% higher tensile index, 49% higher tear index, and 36% higher burst index. To further elevate physical strength, long fibered pulp (LFP), namely commercial softwood sulfate pulp, was mixed with sulfate pulp of palm fiber at levels from 20% to 50%. At the blend level of 50%, tensile index of 52.13 Nœm/g, tear index of 15.63 mNœm2/g, and burst index of 3.42 kPaœm2/g were attained. The lignin in spent liquor from pulping was isolated and characterized. Soda lignin of palm fiber was mainly composed of guaiacyl and syringyl units, and showed weight-average molecular weight of 3616 g/mol.
Journal articles
Flippr° â?? an industrial research project in Austria, TAPPI JOURNAL 2015 March - 15MAR209
Flippr° â?? an industrial research project in Austria, TAPPI JOURNAL 2015 March - 15MAR209
Journal articles
Upgrading aeration system performance in secondary basins treating pulp and paper wastewater: A review, TAPPI JOURNAL June 2015
Upgrading aeration system performance in secondary basins treating pulp and paper wastewater: A review, TAPPI JOURNAL June 2015
Journal articles
2015 TAPPI Centennial Celebration, TAPPI JOURNAL 2015 March - 15MAR100
2015 TAPPI Centennial CelebrationHonoring Our Past, Inspiring Our Future, TAPPI JOURNAL March 2015
Journal articles
Review of currently available technology for the conversion of woody biomass o value-added products 15MAR160
Review of currently available technology for the conversion of woody biomass to value-added products, TAPPI JOURNAL March 2015
Journal articles
Hardwood pulping kinetics of bulk and residual phases, TAPPI JOURNAL October 2015
Hardwood pulping kinetics of bulk and residual phases, TAPPI JOURNAL October 2015
Journal articles
Quantification of lignin-carbohydrate complexes in hardwood pulps, Part 2: Effects of bleaching chemicals, TAPPI JOURNAL October 2015
Quantification of lignin-carbohydrate complexes in hardwood pulps, Part 2: Effects of bleaching chemicals, TAPPI JOURNAL October 2015
Journal articles
Improving energy efficiency of existing recovery boilers 15FEB105
Improving energy efficiency of existing recovery boilers, TAPPI JOURNAL February 2015
Journal articles
Design of refractory linings for balanced energy efficiency, uptime, and capacity in lime kilns 15FEB141
Design of refractory linings for balanced energy efficiency, uptime, and capacity in lime kilns. TAPPI JOURNAL February 2015