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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
Tetraethyl orthosilicate-containing dispersion coating — water vapor and liquid water barrier properties, TAPPI Journal September 2021
ABSTRACT: An aqueous styrene-butadiene latex dispersion coating containing in-situ processed tetraethyl orthosilicate (TEOS) applied on paperboard demonstrated improved water barrier performance. Coatings containing TEOS equivalent to 0.8% silicon dioxide (SiO2; dry basis) exhibited water vapor performance of < 25 g/m2/day (23°C, 50% relative humidity [RH]) and liquid water barrier performance Cobb 1800 s of < 6 g/m2, when applied as a single-layer 18 g/m2 coating. Cobb 1800 s barrier performance was still good (< 11 g/m2) at coat weights of 7•10 g/m2. The use of filler materials such as kaolin improved the vapor barrier properties of the coating, but this was not critical to the liquid water barrier properties.
Journal articles
Magazine articles
Commercially relevant water vapor barrier properties of high amylose starch acetates: Fact or fiction?, TAPPI Journal September 2021
ABSTRACT: Starches have recently regained attention as ecofriendly barrier materials due to the increased demand for sustainable packaging. They are easily processable by conventional plastics processing equipment and have been utilized for oil and grease barrier applications. While starches have excellent oxygen barrier properties and decent water barrier properties at low relative humidity (RH), they are moisture sensitive, as demonstrated by the deterioration of the barrier properties at higher RH values. Starch esters are chemically modified starches where the hydroxyl group of the starch has been substituted by other moieties such as acetates. This imparts hydrophobicity to starches and has been claimed as a good way of retaining water vapor barrier properties of starches, even at high RH conditions. We studied the water vapor barrier properties of one class of starch esters, i.e., high amylose starch acetates that were assumed to have good water vapor barrier properties. Our investigations found that with a high degree of substitution of hydroxyl groups, the modified starches did indeed show improvements in water vapor response as compared to pure high amylose starch films; however, the barrier properties were orders of magnitude lower than commercially used water vapor barriers like polyethylene. Even though these materials had improved water vapor barrier response, high amylose starch acetates are likely unsuitable as water vapor barriers by themselves, as implied by previous literature studies and patents.
Journal articles
CFD-Based Modeling of Kraft Char Beds â?¢ Part 1: Char Bed Burning Model, TAPPI JOURNAL February 2010
CFD-Based Modeling of Kraft Char Beds • Part 1: Char Bed Burning Model, TAPPI JOURNAL February 2010
Journal articles
Influence of oxidation and cationization on the properties of thermomechanical pulp fibers, TAPPI JOURNAL October 2010
Influence of oxidation and cationization on the properties of thermomechanical pulp fibers, TAPPI JOURNAL October 2010
Journal articles
Characterization of spruce thermomechanical pulps at the fiber cell wall level: a method for quantitatively assessing pulp fiber development using Simonsâ?? stain, TAPPI JOURNAL October 2010
Characterization of spruce thermomechanical pulps at the fiber cell wall level: a method for quantitatively assessing pulp fiber development using Simons’ stain, TAPPI JOURNAL October 2010
Journal articles
Development and validation of an improved drainage testing, TAPPI JOURNAL, April 2000, Vol. 83(4)
Development and validation of an improved drainage testing, TAPPI JOURNAL, April 2000, Vol. 83(4)
Journal articles
High temperature chlorine dioxide bleaching of hardwood kraft pulp, TAPPI JOURNAL, August 2000, Vol. 83(8)
High temperature chlorine dioxide bleaching of hardwood kraft pulp, TAPPI JOURNAL, August 2000, Vol. 83(8)
Journal articles
An engineered approach to paper and print improvement, TAPPI JOURNAL, December 2000, Vol. 83(12)
An engineered approach to paper and print improvement, TAPPI JOURNAL, December 2000, Vol. 83(12)
Journal articles
Deinking of newspaper assisted by steam explosion, TAPPI JOURNAL, December 2000, Vol. 83(12)
Deinking of newspaper assisted by steam explosion, TAPPI JOURNAL, December 2000, Vol. 83(12)