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Model development for real oxygen delignification processes, 2023 PEERS Conference

Using bleaching stage models for benchmarking softwood ECF bleach plants, TAPPI Journal July 2022

ABSTRACT: Steady-state bleaching delignification and brightening models were used to gauge how well elemental chlorine-free (ECF) bleach plants were using chlorine dioxide to bleach 25-kappa softwood brownstocks. Case 1 examined the D0(EOP)D1 portion of Mill 1’s five-stage sequence that brightens the pulp to 86% ISO. Case 2 studied the D0(EO)D1 portion of Mill 2’s four-stage sequence, which brightens the pulp to 82% ISO, and Case 3 re-examined the same bleach plant several years after it made improvements around the extraction stage. The models highlighted days in the previously mentioned cases where high bleach usage occurred, presumably because of high brownstock and/or extraction washer carryover, and days where bleach usage was normal. In Case 2, the model esti-mated that 10 kg of the 44 kg chlorine dioxide/metric ton pulp consumed in bleaching was likely reacting with washer carryover sources; approximately two-thirds of this extra consumption was assumed to be reacting with extraction filtrate. Changes that Mill 2 made (Case 3) reduced the unproductive chlorine dioxide usage from 10 to 5 kg/metric ton pulp. When the delignification and brightening models were simultaneously solved, the models predicted somewhat different optimized distributions of chlorine dioxide to D0 and D1 vs. actual values used in bleach plants. However, the forecasted chlorine dioxide totals agreed with the actual values when washer carryover sources were considered. This study showed the bleaching models could be used as hypothetical benchmarks for softwood ECF bleach plants.

Dynamic CFD Modelling of Calcination in a Rotary Lime Kiln with an External Dryer, 2022PEERS/IBBC Conference (22PEE/22IBB)

Improve Deinking Flotation from the Fundamental Research, 2022PEERS/IBBC Conference (22PEE/22IBB)

Techno-economic analysis of hydrothermal carbonization of pulp mill biosludge, TAPPI Journal March 2023

ABSTRACT: For many mills, the biosludge from wastewater treatment is difficult to recycle or dispose of. This makes it a challenging side stream and an important issue for chemical pulping. It often ends up being burned in the recovery or biomass boiler, although the moisture and non-process element (NPE) contents make it a problematic fuel. Biosludge has proven resistant to attempts to reduce its moisture. When incinerated in the biomass boiler, the heat from dry matter combustion is often insufficient to yield positive net heat. Mixing the sludge with black liquor in the evaporator plant for incineration in the recovery boiler is more energy efficient, but is still an additional load on the evaporator plant, as well as introducing NPEs to the liquor. In this study, treating the biosludge by hydrother-mal carbonization (HTC), a mild thermochemical conversion technology, is investigated. The HTC process has some notable advantages for biosludge treatment; taking place in water, it is well suited for sludge, and the hydrochar product is much easier to dewater than untreated sludge. In this study, two HTC plant designs are simulated using IPSEpro process simulation software, followed by economic analysis. Low temperature levels are used to minimize investment costs and steam consumption. The results show that if the sludge is incinerated in a biomass boiler, payback periods could be short at likely electricity prices. The HTC treatment before mixing the sludge with black liquor in the evaporator plant is profitable only if the freed evaporator capacity can be used to increase the firing liquor dry solids content.

Implementation of the Near-Neutral Chlorine Dioxide Brightening Technology at Domtar Johnsonburg Mill, 2018 PEERS

Implementation of the Near-Neutral Chlorine Dioxide Brightening Technology at Domtar Johnsonburg Mill, 2018 PEERS

Fast and Accurate Online Measurement of Differentiated Lignin and HexA Kappa Numbers Leads to Improved Fiberline Control, 2018 PEERS

Fast and Accurate Online Measurement of Differentiated Lignin and HexA Kappa Numbers Leads to Improved Fiberline Control, 2018 PEERS

Technological Evaluation of Pinus maximinoi Wood for Industrial Use in Kraft Pulp Production, 2018 PEERS

Technological Evaluation of Pinus maximinoi Wood for Industrial Use in Kraft Pulp Production, 2018 PEERS

ECONOMIC FUNDAMENTALS OF OZONE BLEACHING, 2018 PEERS

ECONOMIC FUNDAMENTALS OF OZONE BLEACHING, 2018 PEERS

From Physical Modeling to CFD: - 20 Years of Development in Kiln Modeling Techniques, 2018 PEERS

From Physical Modeling to CFD: - 20 Years of Development in Kiln Modeling Techniques, 2018 PEERS