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Journal articles
A review of gas flows in fiber suspensions, TAPPI JOURNAL, Online Exclusive, November 2003, Vol. 2(11) (775KB)
A review of gas flows in fiber suspensions, TAPPI JOURNAL, Online Exclusive, November 2003, Vol. 2(11) (775KB)
Journal articles
An Assessment of Gasification-Based Biorefining at Kraft Pulp and Paper Mills in the United States, Part A: Background and Assumptions, TAPPI JOURNAL November 2008
An Assessment of Gasification-Based Biorefining at Kraft Pulp and Paper Mills in the United States, Part A: Background and Assumptions, TAPPI JOURNAL November 2008
Journal articles
Improvement of the Fiber-Bonding Capacity of Unbleached Recycled Pulp by the Laccase/Mediator Treatment, TAPPI JOURNAL October 2008
Improvement of the Fiber-Bonding Capacity of Unbleached Recycled Pulp by the Laccase/Mediator Treatment, TAPPI JOURNAL October 2008
Journal articles
A mathematical method for determining fiber wall thickness and fiber width , Solutions! & TAPPI JOURNAL, February 2004, Vol. 3(2) (117KB)
A mathematical method for determining fiber wall thickness and fiber width , Solutions! & TAPPI JOURNAL, February 2004, Vol. 3(2) (117KB)
Journal articles
OCC pulp fractionation-a comparative study of fractionated and unfractionated stock, TAPPI JOURNAL, Online Exclusive, January 2004, Vol. 3(1) (KB)
OCC pulp fractionation-a comparative study of fractionated and unfractionated stock, TAPPI JOURNAL, Online Exclusive, January 2004, Vol. 3(1) (KB)
Journal articles
Continuous Time Domain Characterization of Mixing in Agitated Pulp Chests, TAPPI JOURNAL May 2008
Continuous Time Domain Characterization of Mixing in Agitated Pulp Chests, TAPPI JOURNAL May 2008
Journal articles
Isolation of Residual Kraft Lignin in High Yield and Purity, JOURNAL OF PULP AND PAPER SCIENCE: VOL. 28 NO. 2 FEBRUARY 2002 [02FEBJP50.pdf]
Isolation of residual kraft lignin in high yield and purity, Journal of Pulp and Paper Science, February 2002, Vol. 28(2) (113KB)
Journal articles
Comparative annual cost efficiency between thermal and chemical oxidation of TRS in kraft mills, TAPPI JOURNAL, July 2005, Vol. 4(7) (200 KB)
Comparative annual cost efficiency between thermal and chemical oxidation of TRS in kraft mills, TAPPI JOURNAL, July 2005, Vol. 4(7) (200 KB)
Journal articles
Magazine articles
Eucalyptus black liquor properties in a lignin extraction process: density, dry solids, viscosity, inorganic, and organic content, TAPPI Journal March 2023
ABSTRACT: Extracting lignin from black liquor is becoming more common, although only a few research papers discuss the impact of the process on the liquor’s primary properties. This work aims to determine the changes in black liquor properties as it undergoes a lignin extraction process using carbon dioxide (CO2). A diluted eucalyptus black liquor sample (DBL) was acidified with CO2 to a final pH of 8.5. After filtration, the kraft lignin was removed, and the filtrated lignin lean black liquor (LLBL) was collected. Five acidified black liquors (ABL) samples were collected during acidification at pH 10.5; 10.0; 9.5; 9.0; and 8.5. The samples were analyzed regarding lignin content in solution, sodium carbonate (Na2CO3), sodium sulfate (Na2SO4), density, dry solids content, and viscosity. While Na2SO4 remained almost constant, Na2CO3 presented an enormous increase in its concentration when comparing DBL with LLBL. As pH decreased, the lignin content in the solution was also reduced due to lignin precipitation. The results showed similar behavior for dry solids, density, and viscosity of the supernatant, but an increase in density was observed around pH 9.00. In light of this, the density of LLBL turns out to be closer to the one in the initial DBL. The significant increase in carbonate content could explain this behavior during acidification with CO2 once the inorganic content significantly influences the property. The viscosity was determined from 10 s-1 to 2000 s-1. We observed a Newtonian behavior for all samples. The increase in carbonate content in the sample is crucial information to the recovery cycle, especially for calculating the mass and energy balance when targeting the use of the LLBL.
Journal articles
Magazine articles
On the diagnosis of a fouling condition in a kraft recovery boiler: combining process knowledge and data-based insights, TAPPI Journal March 2023
ABSTRACT: Fouling is still a major challenge for the operation of kraft recovery boilers. This problem is caused by accumulation of ash deposits on the surfaces of heat exchangers in the upper part of the boiler over time. The first consequence is the reduction of steam production due to loss of heat transfer and, finally, the shutdown of the boiler due to clogging. The present work investigated the operational condition of a modern kraft boiler under a critical fouling condition. This boiler had even faced a manual cleaning due to a clogging event. This analysis combined process knowledge, plant team experience, and a data-driven approach, given the complexity of the process. In this sense, historical data covering this critical period of operation were collected. After a cleaning procedure, they were used to obtain a predictive neural network model for the flue gas pressure drop in the boiler bank, which is an indirect measure of ash deposit accumulation. Once validated, it was used for sensitivity analysis, with the aim of quantifying the effects of the model inputs. Five variables out of eighteen accounted for nearly 60% of the total effect on pressure drop. Namely, primary air temperature (21.6% of the total effect) and flow rate (11.1%), black liquor flow rate (9.9%) and temperature (8.4%), and white liquor sulfidity (8.6%). The analysis of these results mainly suggested an excess of carryover, which composes the ash deposits. Recommended actions to mitigate the fouling condition involved adjustments to the primary air system before the more drastic solution of reducing the boiler load.