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Factors affecting the free shrinkage of handsheets: apparent density, fines content, water retention value, and grammage, TAPPI JOURNAL June 2018
Factors affecting the free shrinkage of handsheets: apparent density, fines content, water retention value, and grammage, TAPPI JOURNAL June 2018
Journal articles
Magazine articles
Using online bubble size and total dissolved solids measurements to investigate the performance of oxygen delignification, TAPPI JOURNAL June 2018
Using online bubble size and total dissolved solids measurements to investigate the performance of oxygen delignification, TAPPI JOURNAL June 2018
Journal articles
Magazine articles
Creasing severity and reverse-side cracking, TAPPI Journal April 2020
ABSTRACT: Crease cracking can be detrimental to the functionality and appearance of paperboard-based packaging. The effect of creasing severity on the degree of reverse-side crease cracking (bead-side of the crease) of paperboard was investigated. Samples were creased with a range of rule and channel geometries, and the cracking degree was quantified as the percent of cracked length relative to the total length of the crease. The cracking degree was typically below 5% at low crease penetration depths, but was exponentially higher beyond a critical penetration depth. A rule and channel combination with a wider clearance shifted the critical depth to larger values. The creasing severity parameter, termed the creasing draw, converged the cracking degree data from different rule and channel combinations to a single curve. The creasing draw was derived from the same analytical expres-sions as the transverse shear strain and quantifies the length of paper that is drawn into the channel during creasing. The critical draw is defined as the draw at which cracking becomes greater than 5%, which corresponds with the point at which cracking becomes exponential. The critical draw is a material/system parameter that defines the level below which cracking is minimal.
Journal articles
Effects of silica on chemical recovery in the direct caustic
Effects of silica on chemical recovery in the direct causticization of wheat straw black liquor, TAPPI JOURNAL August 2016
Journal articles
Magazine articles
Stiffness and strength properties of five paperboards and their moisture dependency, TAPPI Journal February 2020
ABSTRACT: Five commercial multiply folding boxboards made on the same paperboard machine have been analyzed. The paperboards were from the same product series but had different grammage (235, 255, 270, 315, 340 g/m2) and different bending stiffness. The paperboards are normally used to make packages, and because the bending stiffness and grammage varies, the performance of the packages will differ. Finite element simulations can be used to predict these differences, but for this to occur, the stiffness and strength properties need to be deter-mined. For efficient determination of the three-dimensional properties in the machine direction (MD), cross direction (CD), and Z direction (ZD), it is proposed that the paperboard should be characterized using in-plane tension, ZD-tension, shear strength profiles, and two-point bending. The proposed setups have been used to determine stiff-ness and strength properties at different relative humidity (20,% 50%, 70%, and 90% RH), and the mechanical proper-ties have been evaluated as a function of moisture ratio.There was a linear relation between mechanical properties and moisture ratio for each paperboard. When the data was normalized with respect to the standard climate (50% RH) and plotted as a function of moisture ratio, it was shown that the normalized mechanical properties for all paperboards coincided along one single line and could therefore be expressed as a linear function of moisture ratio and two constants.Consequently, it is possible to obtain the mechanical properties of a paperboard by knowing the structural properties for the preferred level of RH and the mechanical property for the standard climate (50% RH and 23°C).
Journal articles
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Using multistage models to evaluate how pulp washing after the first extraction stage impacts elemental chlorine-free bleach demand, TAPPI Journal November 2018
Using multistage models to evaluate how pulp washing after the first extraction stage impacts elemental chlorine-free bleach demand, TAPPI Journal November 2018
Journal articles
Magazine articles
Production of polyhydroxyalkanoates (PHA)-based renewable packaging materials using photonic energy: A bench and pilot-scale study, TAPPI Journal October 2018
Production of polyhydroxyalkanoates (PHA)-based renewable packaging materials using photonic energy: A bench and pilot-scale study, TAPPI Journal October 2018
Journal articles
Magazine articles
Use of fines-enriched chemical pulp to increase CTMP strength, TAPPI Journal April 2021
ABSTRACT: In this study, fines-enriched pulp (FE-pulp)—the fine fraction of highly-refined kraft pulp—was benchmarked against highly-refined kraft pulp (HRK-pulp) as a strength agent in eucalyptus chemithermomechanical pulp (CTMP). Both the FE-pulp and the HRK-pulp were produced from unbleached softwood kraft pulp, and equal amounts of those strength agents were added to the original CTMP, as well as to washed CTMP, where most of the fines had been removed. The effects of the added strength agents were evaluated with laboratory handsheets.The FE-pulp proved to be twice as effective as HRK-pulp. Both HRK-pulp and FE-pulp increased the strength of the CTMP handsheets. The bulk of the handsheets decreased, however, as well as the drainability. The addition of 5% FE-pulp resulted in the same strength increase as an addition of 10% HRK-pulp, as well as the same decrease in bulk and CSF. For the handsheets of washed CTMP, the strengths were not measurable; the CTMP lost the sheet strength when the CTMP-fines content was reduced through washing. The reduced strength properties were compensated for by the addition of chemical pulp fines that proved to be an efficient strength agent. The addition of 5% FE-pulp restored the strength values, and at a higher bulk and higher drainability.
Journal articles
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Formic acid pulping process of rice straw for manufacturing of cellulosic fibers with silica, TAPPI Journal August 2021
ABSTRACT: Emerging technology has the potential to develop entirely new approaches for producing cellulose fiber-based materials along with fuels and chemical raw materials like lignin and furfural. Rice straw is a rich source of cellulosic fibers and inorganic micronic-sized particles termed as ash. They can prove helpful in development of new or enhanced agricultural residue-based materials and products that offer cost effective substitutes for nonrenewable materials used in different domestic and industrial applications. Lignocellulose is an abundant material that is submicronic at the basic level. Rice straw is a fibrous lignocellulosic material obtained as agricultural residue, but it differs from most crop residues in its high content of silicon dioxide (SiO2). Ash content on a dry weight basis ranges from 13% to 20%, varying according to the state of conservation of the straw after harvest. The ash in rice straw has nearly 75% SiO2. The particle size analysis shows variation from a few microns to hundreds of microns for inorganic residues left after burning at high temperatures above 550°C. Proximate analysis of rice straw shows that it contains 54% to 56% holocellulose and 15% to 18% lignin, both of which are natural biopolymers. The compound analysis shows the different compounds present in rice straw ash.Rice straw is available in hundreds of million tons in India and other Asian countries, so suitable technologies are required to convert rice straw from a biomass waste to useful bioproducts like pulp, paper, and paperboard. This research paper is intended to obtain pulp with fibers having inherent silica present in it to give high opacity paper and better bonding between fibers.
Journal articles
Magazine articles
Can carbon capture be a new revenue opportunity for the pulp and paper sector?, TAPPI Journal August 2021
ABSTRACT: Transition towards carbon neutrality will require application of negative carbon emission technologies (NETs). This creates a new opportunity for the industry in the near future. The pulp and paper industry already utilizes vast amounts of biomass and produces large amounts of biogenic carbon dioxide. The industry is well poised for the use of bioenergy with carbon capture and storage (BECCS), which is considered as one of the key NETs. If the captured carbon dioxide can be used to manufacture green fuels to replace fossil ones, then this will generate a huge additional market where pulp and paper mills are on the front line. The objective of this study is to evaluate future trends and policies affecting the pulp and paper industry and to describe how a carbon neutral or carbon negative pulp and paper production process can be viable. Such policies include, as examples, price of carbon dioxide allowances or support for green fuel production and BECCS implementation. It is known that profitability differs depending on mill type, performance, energy efficiency, or carbon dioxide intensity. The results give fresh understanding on the potential for investing in negative emission technologies. Carbon capture or green fuel production can be economical with an emission trade system, depending on electricity price, green fuel price, negative emission credit, and a mill’s emission profile. However, feasibility does not seem to evidently correlate with the performance, technical age, or the measured efficiency of the mill.