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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
TAPPI Journal Summaries, Paper360º May/June 2021
TAPPI Journal Summaries, Paper360º May/June 2021
Packaging Paper and Board Recycling Line Optimisation: How Can Fine Slot Screening Replace Hot Dispersing? FAL0301
Packaging Paper and Board Recycling Line Optimisation: How Can Fine Slot Screening Replace Hot Dispersing?
Historical Perspectives on Contemporary Problems: Organizational Capabilities and Strategy and Structure, 2003 Fall Technical Conference
Historical Perspectives on Contemporary Problems: Organizational Capabilities and Strategy and Structure, 2003 Fall Technical Conference
MRO Practices and their Link to Improved Competitive Performance, 2003 Fall Technical Conference
MRO Practices and their Link to Improved Competitive Performance, 2003 Fall Technical Conference
Impact Of Chip Thickness Distribution On Chip Packing Density, 2003 Fall Technical Conference
Impact Of Chip Thickness Distribution On Chip Packing Density, 2003 Fall Technical Conference
Packaging Paper and Board Recycling Line Optimisation: How Can Fine Slot Screening Replace Hot Dispersing?, 2003 Fall Technical Conference
Packaging Paper and Board Recycling Line Optimisation: How Can Fine Slot Screening Replace Hot Dispersing?, 2003 Fall Technical Conference
Managing Availability for Improved Bottom Line Results, 2003 Fall Technical Conference
Managing Availability for Improved Bottom Line Results, 2003 Fall Technical Conference
Conference papers
Collaborative Maintenance Strategies Help Manufacturers Become Lean, Mean and Agile, 2003 Fall Technical Conference
Collaborative Maintenance Strategies Help Manufacturers Become Lean, Mean and Agile, 2003 Fall Technical Conference
Assessing Plant Potential for Asset Management, 2003 Fall Technical Conference
Assessing Plant Potential for Asset Management, 2003 Fall Technical Conference