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Magazine articles
Development of converging-diverging multi-jet nozzles for molten smelt shattering in kraft recovery boilers, TAPPI Journal March 2021
ABSTRACT: The effective shattering of molten smelt is highly desired in recovery boiler systems. Ideally, shatter jet nozzle designs should: i) generate high shattering energy; ii) create a wide coverage; and iii) minimize steam consumption. This study proposes a novel converging-diverging multi-jet nozzle design to achieve these goals. A laboratory setup was established, and the nozzle performance was evaluated by generating jet pressure profiles from the measurement of a pitot tube array. The results show that the shatter jet strength is greater with a large throat diameter, high inlet pressure, and a short distance between the nozzle exit and impingement position. Increasing the number of orifices generates a wider jet coverage, and the distance between the orifices should be limited to avoid the formation of a low-pressure region between the orifices. The study also demonstrates that an optimized converging-diverging multi-jet nozzle significantly outperformed a conventional shatter jet nozzle by achieving higher energy and wider coverage while consuming less steam.
Journal articles
Magazine articles
Black liquor evaporator upgrades— life cycle cost analysis, TAPPI Journal March 2021
ABSTRACT: Black liquor evaporation is generally the most energy intensive unit operation in a pulp and paper manufacturing facility. The black liquor evaporators can represent a third or more of the total mill steam usage, followed by the paper machine and digester. Evaporator steam economy is defined as the unit mass of steam required to evaporate a unit mass of water from black liquor (i.e., lb/lb or kg/kg.) The economy is determined by the number of effects in an evaporator train and the system configuration. Older systems use four to six effects, most of which are the long tube vertical rising film type. Newer systems may be designed with seven or even eight effects using falling film and forced circulation crystallization technology for high product solids. The median age of all North American evaporator systems is 44 years. Roughly 25% of the current North American operating systems are 54 years or older. Older systems require more periodic maintenance and have a higher risk of unplanned downtime. Also, older systems have chronic issues with persistent liquor and vapor leaks, shell wall thinning, corrosion, and plugged tubes. Often these issues worsen to the point of requiring rebuild or replacement. When considering the age, technology, and lower efficiency of older systems, a major rebuild or new system may be warranted. The intent of this paper is to review the current state of black liquor evaporator systems in North America and present a basic method for determining whether a major rebuild or new installation is warrant-ed using total life cycle cost analysis (LCCA).
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.
Magazine articles
On management: energy and the pulp and paper industry - how will electric utility deregulation affect You?, TAPPI JOURNAL, March 1998, Vol. 81(3)
On management: energy and the pulp and paper industry - how will electric utility deregulation affect You?, TAPPI JOURNAL, March 1998, Vol. 81(3)
Magazine articles
English as a first and second language - part 6: avoiding grammar traps, TAPPI JOURNAL, September 1998, Vol. 81(9)
English as a first and second language - part 6: avoiding grammar traps, TAPPI JOURNAL, September 1998, Vol. 81(9)
Magazine articles
Mondi in south africa, TAPPI JOURNAL, April 1999, Vol. 82(4)
Mondi in south africa, TAPPI JOURNAL, April 1999, Vol. 82(4)
Magazine articles
Forest products industry partners with government on r&d projects, TAPPI JOURNAL, April 1999, Vol. 82(4)
Forest products industry partners with government on r&d projects, TAPPI JOURNAL, April 1999, Vol. 82(4)
Magazine articles
Views from the top: ceos offer global perspectives on the pulp and paper industries, TAPPI JOURNAL, August 1999, Vol. 82(8)
Views from the top: ceos offer global perspectives on the pulp and paper industries, TAPPI JOURNAL, August 1999, Vol. 82(8)
Magazine articles
UGA warnell school of forest resources builds mobile lab for wastewater analyses and management, TAPPI JOURNAL, December 1999, Vol. 82(12)
UGA warnell school of forest resources builds mobile lab for wastewater analyses and management, TAPPI JOURNAL, December 1999, Vol. 82(12)
Magazine articles
Corrosion in fluidized bed boilers burning potassium and chlorine containing fuels, TAPPI JOURNAL, June 1999, Vol. 82(6)
Corrosion in fluidized bed boilers burning potassium and chlorine containing fuels, TAPPI JOURNAL, June 1999, Vol. 82(6)