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Boiler retrofit improves efficiency and increases biomass firing rates, TAPPI Journal March 2021
ABSTRACT: Domtar’s fluff pulp mill in Plymouth, NC, USA, operates two biomass/hog fuel fired boilers (HFBs). For energy consolidation and reliability improvement, Domtar wanted to decommission the No. 1 HFB and refurbish/retrofit the No. 2 HFB. The No. 2 HFB was designed to burn pulverized coal and/or biomass on a traveling grate. The steaming capacity was 500,000 lb/h from coal and 400,000 lb/h from biomass. However, it had never sustained this design biomass steaming rate. As the sole power boiler, the No. 2 HFB would need to sustain 400,000 lb/h of biomass steam during peak loads. An extensive evaluation by a combustion and boiler technologies supplier was undertaken. The evaluation involved field testing, analysis, and computational fluid dynamics (CFD) modeling, and it identified several bottle-necks and deficiencies to achieving the No. 2 HFB’s biomass steam goal. These bottlenecks included an inadequate combustion system; insufficient heat capture; excessive combustion air temperature; inadequate sweetwater con-denser (SWC) capacity; and limited induced draft fan capacity.To address the identified deficiencies, various upgrades were engineered and implemented. These upgrades included modern pneumatic fuel distributors; a modern sidewall, interlaced overfire air (OFA) system; a new, larger economizer; modified feedwater piping to increase SWC capacity; replacement of the scrubber with a dry electrostatic precipitator; and upgraded boiler controls.With the deployment of these upgrades, the No. 2 HFB achieved the targeted biomass steaming rate of 400,000 lb/h, along with lowered stack gas and combustion air temperatures. All mandated emissions limit tests at 500,000 lb/h of steam with 400,000 lb/h of biomass steam were passed, and Domtar reports a 10% reduction in fuel firing rates, which represents significant fuel savings. In addition, the mill was able to decommission the No. 1 HFB, which has substantially lowered operating and maintenance costs.
Journal articles
Magazine articles
What is Our Industry’s Most Critical Workforce Need?, Paper360º March/April 2021
What is Our Industry’s Most Critical Workforce Need?, Paper360º March/April 2021
Journal articles
Magazine articles
Peracetate/singlet oxygen chemistry used in post-bleaching of kraft pulp as a practical oxidant for paper machines, TAPPI Journal May 2021
ABSTRACT: The use of a novel sodium peracetate/singlet oxygen chemistry for brightening bleached kraft pulp shows exciting potential for technical performance, supply logistics, safety, and cost reduction. Potential chemical carryover to the paper machine raises questions about whether peracetate will impact paper machine performance, such as metal corrosion, useful press felt life, and interference with existing biocide programs or paper machine chemistry. Sodium peracetate/singlet oxygen chemistry can be used in high-density storage chests for brightening/whitening and to increase color stability. Any oxidant used directly before the paper machine has the possibility of impacting paper machine operations. Traditional oxidants used in bleaching, such as chlorine dioxide and hydrogen peroxide, are known to cause corrosion on machinery metals and press felts. Hydrogen peroxide residuals can interfere with common biocide programs. Traditional oxidants used in biocide treatments themselves significantly degrade press felt life when the rule-of-thumb concentration thresholds are exceeded. Sodium peracetate is evaluated in this paper for its impact on nylon press felt fiber degradation, metal corrosion, and interference with typical biocide programs.Laboratory results indicate that sodium peracetate/singlet oxygen chemistry is less corrosive than chlorine, bromine, and hydrogen peroxide on press felt nylon fiber and can therefore be used at higher levels than those chemistries to increase brightness without increasing negative downstream impact. Sodium peracetate can also be used with current biocide programs without negative impacts such as consumptive degradation. Higher residuals of peracetate going to the paper machine may be useful as a biocide itself and can complement existing programs, allowing those programs to stay within their safe operating levels and thereby extend press felt useful life.
Journal articles
Magazine articles
Li-ion Batteries are Making a Roar, Paper360º May/June 2021Li-ion Batteries are Making a Roar, Paper360º May/June 2021
Li-ion Batteries are Making a Roar, Paper360º May/June 2021
Journal articles
Magazine articles
The Future of Sustainability at Pulp and Paper Mills, Paper360º November/December 2021
The Future of Sustainability at Pulp and Paper Mills, Paper360º November/December 2021
Journal articles
Magazine articles
Getting Color ´In Line’, Paper360º November/December 2021
Getting Color ´In Line’, Paper360º November/December 2021
Journal articles
New High Barrier Lidding Materials: Optimization Studies to Understand Seal Peel Characteristics to Different Consumer Cup Substrates
New High Barrier Lidding Materials: Optimization Studies to Understand Seal Peel Characteristics to Different Consumer Cup Substrates
Journal articles
On-line Gauging as a Process Troubleshooting Tool, 2006 PLACE Conference
On-line Gauging as a Process Troubleshooting Tool, 2006 PLACE Conference
Journal articles
Treatment of edta-containing pulp and paper mill wastewaters in activated sludge plants, TAPPI JOURNAL, February 1999, Vol. 82(2)
Treatment of edta-containing pulp and paper mill wastewaters in activated sludge plants, TAPPI JOURNAL, February 1999, Vol. 82(2)
Journal articles
Shop talk: improving dryer performance: converting to stationary siphons with turbulence bars, TAPPI JOURNAL, April 1999, Vol. 82(4)
Shop talk: improving dryer performance: converting to stationary siphons with turbulence bars, TAPPI JOURNAL, April 1999, Vol. 82(4)