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Evaluation of soap recovery efficiency from black liquor — analytical tools, TAPPI Journal April 2023
ABSTRACT: Soap skimmings (“soap”) are typically recovered from black liquor in kraft mills that process a high percentage of softwood. In many mills, the recovery of soap is inefficient, negatively impacting performance of evaporators and recovery boilers and resulting in loss of potential revenue. A thorough evaluation of soap recovery performance in a kraft mill requires measurement of soap content in black liquor at various sampling locations, especially around the soap skimmer.The standard laboratory method for evaluating soap content in black liquor is a complex, multi-step process that relies on solvent extraction and titration; most mills send these samples to an outside laboratory for this analysis. In this study, 100 black liquor samples, with a wide range of soap concentrations, were tested by the standard solvent extraction method. After additional dilution, each sample was also tested for surface tension with a bubble pressure tensiometer. The results were found to correlate very closely with the solvent extraction tests results. This alternate method, using surface tension measurements of diluted black liquor samples, produces rapid results and can be easily implemented in most kraft mills, which would facilitate much more frequent in-house evaluations of soap recovery performance.
Journal articles
Characterization of refined papermaking pulps using hydrodynamic parameters from filtration analysis, TAPPI JOURNAL May 2015
Characterization of refined papermaking pulps using hydrodynamic parameters from filtration analysis, TAPPI JOURNAL May 2015
Journal articles
Application of lipase to reduce ONP flotation rejects: Part 2. Reduction of flotation rejects, TAPPI JOURNAL, August 2008
Application of lipase to reduce ONP flotation rejects: Part 2. Reduction of flotation rejects, TAPPI JOURNAL, August 2008
Journal articles
Characterizing Carbonaceous Biochemical Oxygen Demand Load Reductions from Pulp and Paper Mills for Activities Related to Total Maximum Daily Loads, TAPPI JOURNAL January 2009
Characterizing Carbonaceous Biochemical Oxygen Demand Load Reductions from Pulp and Paper Mills for Activities Related to Total Maximum Daily Loads, TAPPI JOURNAL January 2009
Journal articles
A financial analysis of north american pulp, paper and packaging firms, TAPPI JOURNAL, September 1999, Vol. 82(9)
A financial analysis of north american pulp, paper and packaging firms, TAPPI JOURNAL, September 1999, Vol. 82(9)
Journal articles
Magazine articles
Viscoelastic web curl due to storage in wound rolls, TAPPI Journal July 2020
ABSTRACT: Winding is often the final operation in a roll-to-roll manufacturing process. Web materials, i.e., materials that are thin compared to their length, are wound into rolls because this form is the only practical means to store them. The resulting bending strains and associated stresses are large for thick webs and laminates. As many webs are viscoelastic on some time scale, bending stresses lead to creep and inhomogeneous changes in length. When the web material is unwound and cut into discrete samples, a residual curvature remains. This curvature, called curl, is the inability for the web to lie flat at no tension. Curl is an undesirable web defect that causes loss of productivity in a subsequent web process. This paper describes the development and implementation of modeling and experimental tools to explore and mitigate curl in homogenous webs. Two theoretical and numerical methods that allow the prediction of curl in a web are developed: a winding software based on bending recovery theory, and the implementation of dynamic simula-tions of winding. One experimental method is developed that directly measures the curl online by taking advantage of the anticlastic bending resulting from the curl. These methods are demonstrated for a low-density polyethylene web.
Journal articles
Magazine articles
Case study: Paper mill power plant optimization—balancing steam venting with mill demand, TAPPI Journal June 2020
ABSTRACT: Most Power departments are tasked with generating steam to support mill wide operations, generate electricity, and reduce operating costs. To accomplish these tasks, power boilers generate high pressure steam that is reduced to intermediate and low pressures for process utilization in the mill by means of steam turbine generator extraction or pressure reducing valves. The most economical method to reduce steam pressure is the use of steam turbine generators, as electricity is generated from the steam when it is reduced in pressure. Electricity that is produced by these generators provides a substantial financial benefit and helps offset overall operational costs. To achieve tangible financial gains, the mill must evaluate the overall cost of steam production and the price of electricity.The current work provides a case study of power plant optimization that evaluated electricity production and steam production costs balanced with mill steam demand. Process and cost optimization led to a significant reduc-tion in low pressure steam venting, resulting in reduced fuel consumption and reduced operating cost.
Journal articles
Industry characteristics and investment decisions: an alternative approach to pulp and paper production, TAPPI JOURNAL, January 1998, Vol. 81(1)
Industry characteristics and investment decisions: an alternative approach to pulp and paper production, TAPPI JOURNAL, January 1998, Vol. 81(1)
Journal articles
Setting the record straight, TAPPI JOURNAL, July 1998, Vol. 81(7)
Setting the record straight, TAPPI JOURNAL, July 1998, Vol. 81(7)
Journal articles
New opportunities in the South American pulp and paper business, TAPPI JOURNAL, June 1998, Vol. 81(6)
New opportunities in the south american pulp and paper business, TAPPI JOURNAL, June 1998, Vol. 81(6)