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Characterization of Lignin Gasification and Pyrolysis, 2008 Engineering, Pulping and Environmental Conference
Characterization of Lignin Gasification and Pyrolysis, 2008 Engineering, Pulping and Environmental Conference
CHLORATE REDUCTION IN EUCALYPTUS PULP BLEACHING, 2008 Engineering, Pulping and Environmental Conference
CHLORATE REDUCTION IN EUCALYPTUS PULP BLEACHING, 2008 Engineering, Pulping and Environmental Conference
Determination of the permeability parameters of bagasse pulp from two different sugar extraction methods, 2008 Engineering, Pulping and Environmental Conference
Determination of the permeability parameters of bagasse pulp from two different sugar extraction methods, 2008 Engineering, Pulping and Environmental Conference
Evaporator and Concentrator Design Considerations for Troubleshooting, 2008 Engineering, Pulping and Environmental Conference
Evaporator and Concentrator Design Considerations for Troubleshooting, 2008 Engineering, Pulping and Environmental Conference
GUIDED TOUR: IMPLEMENTING THE FOREST BIOREFINERY (FBR) AT EXISTING PULP AND PAPER MILLS, 2008 Engineering, Pulping and Environmental Conference
GUIDED TOUR: IMPLEMENTING THE FOREST BIOREFINERY (FBR) AT EXISTING PULP AND PAPER MILLS, 2008 Engineering, Pulping and Environmental Conference
Production of Ethanol from Forest Residues and Hog Fuel in a Pulp Mill, 2008 Engineering, Pulping and Environmental Conference
Production of Ethanol from Forest Residues and Hog Fuel in a Pulp Mill, 2008 Engineering, Pulping and Environmental Conference
The Fate of Silver from Recycled Printed Electronic Circuits, 2008 Engineering, Pulping and Environmental Conference
The Fate of Silver from Recycled Printed Electronic Circuits, 2008 Engineering, Pulping and Environmental Conference
Use of Urea as an Additive in Kraft Pulping of Eucalyptus, 2008 Engineering, Pulping and Environmental Conference
Use of Urea as an Additive in Kraft Pulping of Eucalyptus, 2008 Engineering, Pulping and Environmental Conference
Journal articles
Magazine articles
CFD and predictive modeling of temperature and calcination in a rotary lime kiln • Potential for steadier kiln operation, TAPPI Journal October 2024
ABSTRACT: Rotary lime kilns are used in the pulp and paper industry to calcine lime mud to lime. Lime kiln models provide a means to understand the complex phenomena occurring within the kiln to aid in problem-solving during operation. A two-dimensional (2D) computational fluid dynamics (CFD) and one-dimensional (1D) bed model was previously developed for steady-state and transient analysis. This study explores data extracted from the model over a longer time period. The simulated outlet gas and shell temperature are compared to measured data for validation. The capability of using the model to estimate the production rate, accounting for the residence time within the kiln, is discussed. The maximum refractory wall temperature is analyzed during operation. Fluctuations in the calcination location are compared to outer shell heat-map data to correlate the calcination location and ring formation and growth. The model results to date indicate that fluctuations in the calcination zone may contribute to problematic ring growth, though a direct correlation has yet to be established. Additionally, a method for steadier kiln control is introduced and discussed. A machine learning model is also developed to predict the calcination start location from industrial data and is compared to the CFD model for validation. This model can generate results quickly and without the need for knowledge in CFD software and theory. Good agreement is found between the CFD and machine learning model during operation, with a mean absolute error (MAE) of 0.46 m, a mean absolute percentage error (MAPE) of 0.92%, and a root mean square error (RMSE) of 1.17 m.
Journal articles
Magazine articles
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.