Search results for "Kraft paper"

FORMATION OF ALIPHATIC CARBOXYLIC ACIDS DURING ALKALINE PULPING OF MULI BAMBOO

2002

ABSTRACT A study on the formation of aliphatic carboxylic acids, i.e., formic and acetic acids and various hydroxy monocarboxylic and dicarboxylic acids, during soda-AQ, kraft, and kraft-AQ pulping of muli bamboo (Melocanna baccifera) was carried out. Detailed gas chromatographic analyses revealed that the most abundant hydroxy carboxylic acids were 2-hydroxybutanoic, lactic, glucoisosaccharinic, glycolic, xyloisosaccharinic, 3,4-dideoxypentonic, and 3-deoxypentonic acids. The presence of AQ depressed the formation of 2-hydroxybutanoic, xyloisosaccharinic, and glucoisosaccharinic acids, and accelerated the formation of glycolic and 3-deoxypentonic acids as well as 3-deoxytetronic acid but h…

Quantitative determination of the main aliphatic carboxylic acids in wood kraft black liquors by high-performance liquid chromatography-mass spectrom…

2006

The versatile characterization of organic material and especially of the significant aliphatic hydroxy acids in black liquor is of great importance, for example, in monitoring the progress of the kraft pulping process. This paper describes a simple high-performance liquid chromatographic separation method with atmospheric-pressure chemical ionization mass spectrometry (HPLC-APCI-MS) which was developed for the rapid quantitative analysis of these acids, mainly formed as the alkaline degradation products of feedstock carbohydrates. The fraction of carbohydrate degradation products is mainly composed of hydroxy monocarboxylic and volatile acids (formic and acetic acids) along with lesser amou…

Behavior of carbohydrate-based material in black liquor during heating

2004

One industrial softwood Kraft black liquor was heat-treated (at 175 ?C and 190 ?C for 15-60 min) together with laboratory-made soda-AQ (wheat straw and reed canary grass) and Kraft (reed canary grass) black liquors (at 190 ?C for 30 min). The feedstock black liquors were characterized with respect to their polysaccharide (mainly xylem) and aliphatic carboxylic acid contents before and after the heat treatments. It was noted that, due to the higher amount of polysaccharides in the non-wood black liquors (8.2-16.6% of d.s) compared to that in the softwood black liquor (1.4% of d.s), the heat treatment in the former case resulted in a 5-30% increase in the amount of aliphatic acids formed by v…

Multivariate correlation between13C and31P NMR spectral data on dissolved lignin and the combustion properties of kraft black liquor

1999

Characterization of totally chlorine-free effluents from kraft pulp bleaching III

1999

Abstract Chemical changes in the dissolved high-molecular-mass material from silver birch (Betula pendula) kraft pulp during the oxygen–alkali delignification stage (O) and the subsequent totally chlorine-free (TCF) bleaching sequence (X–Z–EOP–AZ–EP–S) were investigated by analytical pyrolysis (pyrolysis–gas chromatography/mass-sensitive detector (Py–GC/MSD)). In addition, the pyrolysis data were subjected to chemometric analysis, resulting in a rapid method for determining with reasonable accuracy, for example, the mass proportion of carbohydrates and lignin in the effluents from each of the treatment stages. The method was calibrated by chemical analysis on the same effluents.

Innovative Recycling of Lime Slaker Grits from Paper-Pulp Industry Reused as Aggregate in Ambient Cured Biomass Fly Ash-Based Geopolymers for Sustain…

2019

Lime slaker grits and biomass fly ash are solid wastes produced by the Kraft paper-pulp industry that are commonly disposed of in landfill. However, recent studies and European regulations discourage such disposal practices. This work investigates an alternative and innovative way to recycle and reuse these wastes in the production of green geopolymeric mortars intended for application in the construction industry. Here, biomass fly ash was used as the main source of alumino-silicate in the binder precursor (70 wt.% substitution to metakaolin), and grits (ranging from 1&ndash

Recovery of aliphatic low-molecular-mass carboxylic acids from hardwood kraft black liquor

2015

Abstract During alkaline pulping of wood, substantial amounts of carbohydrates-derived aliphatic carboxylic acids (formic and acetic acids together with various hydroxy acids) are formed and dissolved into the cooking liquor (“black liquor”). These acids with low heating values are considered to be potential feedstocks for the chemical industry but, due to many factors, their straightforward recovery as free acids from black liquor (pH 13–14) is difficult. In this paper, we outlined the partial recovery of volatile formic and acetic acids from the acidified birch ( Betula pendula ) kraft black liquor (pH approximately 2.5) by distillation, and the partial recovery of significant low-molecul…

Lignin recovery from spent alkaline pulping liquors using acidification, membrane separation, and related processing steps: A Review

2019

The separation of lignin from the black liquor generated during alkaline pulping is reviewed in this article with an emphasis on chemistry. Based on published accounts, the precipitation of lignin from spent pulping liquor by addition of acids can be understood based on dissociation equilibria of weak acid groups, which affects the solubility behavior of lignin-related chemical species. Solubility issues also govern lignin separation technologies based on ultrafiltration membranes; reduction in membrane permeability is often affected by conditions leading to decreased solubility of lignin decomposition products and the presence of colloidal matter. Advances in understanding of such phenomen…

Effects of integrating a bioethanol production process to a kraft pulp mill

2010

Abstract The integration of an ethanol production process based on prehydrolysis of softwood chips to a kraft pulp mill is discussed. A simulation model of this biorefinery has been created with WinGEMS simulation software to calculate the mass and energy balances of the biorefinery and to examine the effects of the integration on the operation of the pulp mill. Integrating the prehydrolysis process to the modeled pulp mill producing 1000 Adt/day of pine pulp would increase the wood consumption by 16%. With the increased wood consumption, 40 t/day of ethanol could be produced, and the excess power production could be increased by 460 MWh/day. The integration of the ethanol production proces…