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Journal articles
Magazine articles
Open Access
Modeling the dynamics of evaporator wash cycles, TAPPI Journal July 2024

ABSTRACT: Kraft pulping is a process that utilizes white liquor, composed of sodium sulfide (Na2S) and sodium hydroxide (NaOH), for wood delignification and pulp production. This process involves washing the dissolved organics and spent chemicals from the pulp, resulting in the generation of black liquor. Prior to its use as fuel in the recovery boiler, the black liquor is concentrated in multiple-effect evaporators. During the evaporation process, the inorganic salts present in the liquor become supersaturated and undergo crystallization. Fluctuations in sodium, carbonate, sulfate, and oxalate can give rise to severe sodium salt scaling events, which significantly impact the thermal efficiency of the evaporators, and ultimately, pulp production. Dynamic modeling provides insights into fluctuations in liquor chemistry in the evaporators. The primary objective of this study was to employ dynamic modeling to evaluate the effects of wash liquor recovery from evaporator wash cycles. The dynamics associated with wash cycles encompass variations in the concentrations of salts and solids in the recovered wash liquor, changes in the flow rate of wash liquor recovery, and fluctuations in liquor volume within the liquor tanks. The dynamic model was developed using Matlab Simulink and applied to the evaporation plant of a pulp mill in South America. By utilizing one month of mill process data, the model enabled the evaluation of fluctuations in liquor chemistry due to evaporator wash cycles. The developed model has demonstrated the potential to estimate the concentration of key ions responsible for scaling and to contribute to enhancements in evaporator washing strategies.

Conference papers
A Novel One Step Method to Prepare Carboxycellulose Nanofibe

A Novel One Step Method to Prepare Carboxycellulose Nanofibers from Raw Biomass and their Applications to Remediation for Heavy Metal Ions. 2017PEERS

Conference papers
Developing LignoBoost for the end user lignin quality requir

Developing LignoBoost for the end user lignin quality requirements, 2017PEERS

Conference papers
Kinetics of Deacetylation of Northeast Hardwood, 2017PEERS

Kinetics of Deacetylation of Northeast Hardwood, 2017PEERS

Conference papers
Using online bubble size and total dissolved solids (TDS) me

Using online bubble size and total dissolved solids (TDS) measurements to investigate the performance of oxygen delignification, 2017PEERS

Conference papers
Evaluation of Acid Stage and of Hydrogen Peroxide on Alkalin

Evaluation of Acid Stage and of Hydrogen Peroxide on Alkaline Extraction of Eucalyptus Kraft Pulp, 2017PEERS

Conference papers
Decreased Water Usage in a Softwood ECF Bleaching Sequence •

Decreased Water Usage in a Softwood ECF Bleaching Sequence • Full Mill Simulations, 2017PEERS

Journal articles
Magazine articles
Open Access
Lignin-based resins for kraft paper applications, TAPPI Journal November 2019

ABSTRACT: We investigated miscanthus (MS) and willow (W) lignin-furfural based resins as potential reinforce-ment agents on softwood and hardwood kraft paper. These resins might be sustainable alternatives to the commercial phenolformaldehyde (PF) resins. Phenol is a petrochemical product and formaldehyde has been classified as a carcinogen by the U.S. Environmental Protection Agency. The lignin used in this study was derived from hot water extraction (160ºC, 2 h) of MS and W biomass, and may be considered sulfur-free. These biorefinery lignins were characterized for their chemical composition and inherent properties via wet chemistry and instrumental techniques. The resin blends (MS-resin and W-resin) were characterized for their molecular weight, thermal behavior, and mechanical properties. Mechanical properties were measured by the resin’s ability to reinforce softwood and hard-wood kraft papers. The effect of adding hexamethylenetetramine (HMTA), a curing agent, to the resin was also examined. Mixtures of PF and lignin-based resins were investigated to further explore ways to reduce use of non-renewables, phenol, and carcinogenic formaldehyde. The results show that lignin-based resins have the potential to replace PF resins in kraft paper applications. For softwood paper, the highest strength was achieved using W-resin, without HMTA (2.5 times greater than PF with HMTA). For hardwood paper, MS-resin with HMTA gave the highest strength (2.3 times higher than PF with HMTA). The lignin-based resins, without HMTA, also yielded mechanical properties comparable to PF with HMTA.

Conference papers
Impact of Kraft Mill Chemistry on Economics: A Model-Based Approach to Optimizing Mill Profitability, 19PEERS

Impact of Kraft Mill Chemistry on Economics: A Model-Based Approach to Optimizing Mill Profitability, 19PEERS

Conference papers
Fluff Pulp Performance Improved by Alternative Pine Species, 19PEERS

Fluff Pulp Performance Improved by Alternative Pine Species, 19PEERS

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