Multistage oxygen delignification of high-kappa pine kraft pulp with peroxymonosulfuric acid (Px)

Holzforschung ◽  
2014 ◽  
Vol 68 (5) ◽  
pp. 497-504 ◽  
Author(s):  
Vahid Jafari ◽  
Herbert Sixta ◽  
Adriaan van Heiningen
Keyword(s):  
Kraft Pulp ◽  
Ethylenediaminetetraacetic Acid ◽  
Total Yield ◽  
Pulp Yield ◽  
Total Charge ◽  
Oxygen Delignification ◽  
Pulp Viscosity ◽  
Stage Process ◽  
Three Stages ◽  
Pine Wood Chips

Abstract In the present study the advantages of multistage oxygen delignification was explored in comparison with a single-stage process at the same level of total caustic charge. A pine kraft pulp with kappa number of 65 (Kn65) was bleached with the focus on the effect of NaOH-charge distribution on Kn, pulp yield, and selectivity of oxygen delignification. The effect of initial chelation with ethylenediaminetetraacetic acid (EDTA) and interstage pulp treatment with peroxymonosulfuric acid (Px) were also investigated. It is shown that the chelated pulp with high Kn may be delignified in three stages to Kn15, but at an unacceptable reduction in pulp viscosity and yield. In contrast, interstage treatment of the chelated pulp with Px at a total charge of 2% active oxygen (based on pulp) in combination with three stages of oxygen delignification enables Kn reduction to about 15 at acceptable viscosity and total yield advantage of about 0.5% (based on wood) compared to an oxygen-delignified kraft pulp with Kn24 derived from the same pine wood chips.

Effect of lignin content and magnesium-to-manganese ratio on the selectivity of oxygen delignification in softwood kraft pulp

2001 ◽  
Vol 73 (12) ◽  
pp. 2059-2065
Author(s):  
Lucian A. Lucia ◽  
Rachel S. Smereck
Keyword(s):  
Chemical Process ◽  
Kraft Pulp ◽  
Lignin Content ◽  
Dry Mass ◽  
The Other ◽  
Kraft Pulps ◽  
Oxygen Delignification ◽  
Pulp Viscosity ◽  
Softwood Kraft Pulp ◽  
Temperature Time

A series of oxygen delignification experiments were performed on two softwood kraft pulps that had differing starting lignin contents. One had an initial kappa of 40 and the other 25, corresponding to lignin contents of 6% and 3.75% by dry mass, respectively. Several chemical process modifications were examined to determine their influence over the delignification selectivity and final pulp viscosity. A 2k factorial format was used to assess the significance of varying the temperature, time, and Mg/Mn ratio during the oxygen delignification of the pulps. It was found that the lower lignin content pulp displayed greater delignification selectivity than the higher lignin content pulp. Kappa numbers, viscosity values, and ICP metals contents were determined and are the basis of discussion for the results obtained.

Pre-extraction and PSAQ pulping of Siberian larch

2010 ◽  
Vol 25 (2) ◽  
pp. 243-248 ◽  
Author(s):  
Riikka Kämppi ◽  
Hanna Hörhammer ◽  
Anja Leponiemi ◽  
Adriaan van Heiningen
Keyword(s):  
Kraft Pulp ◽  
Total Yield ◽  
Siberian Larch ◽  
Value Added ◽  
Pulp Yield ◽  
Kraft Pulps ◽  
Wood Material ◽  
Yield And Quality ◽  
Optimized Conditions ◽  
Value Added Products

Abstract The aim of this study was to find conditions under which it is possible to produce hemicelluloses-rich extract from Siberian larch in addition to pre-extracted pulp with a yield comparable to normal kraft pulp. The study was conducted in order to determine proof of concept of a process utilizing Siberian larch for production of papermaking pulp and biochemically obtained value-added products, i.e. biofuels or lactic acid. By pre-extraction at 160 ºC for 60 minutes approximately 17% of the wood material could be dissolved. At kappa number 30, the pre-extracted kraft pulp gave 5% lower total yield than a conventional kraft pulp. Addition of 4% polysulfide (PS) and 0.1% anthraquinone (AQ) on wood increased the pre-extracted kraft pulp yield nearly to the same level as that of regular kraft pulp. Pre-extraction at 160 ºC for 60 minutes allowed reduction of EA charge by 3% on wood and Hfactor by 300-450. The viscosity of the pre-extracted PSAQ kraft pulps was higher than that of conventional larch kraft pulps and had a somewhat inferior strength and optical properties. The results indicate that under optimized conditions it is possible to produce preextracted PSAQ larch pulp without significant losses in pulp yield and quality, and in addition generate a new feed stock of carbohydrates for further utilization for value-added products.

A Study on the Strengthened Oxygen Delignification of NaOH-AQ Pulp of Fast Growing Poplar with Low Kappa Number

2012 ◽  
Vol 217-219 ◽  
pp. 895-899
Author(s):  
Xing Xiang Ji ◽  
Jia Chuan Chen ◽  
Gui Hua Yang ◽  
Zhong Jian Tian
Keyword(s):  
Oxygen Pressure ◽  
Kappa Number ◽  
Pulp Yield ◽  
Oxygen Delignification ◽  
Fast Growing ◽  
Pulp Viscosity ◽  
Pulp Consistency ◽  
Temperature Time

In this paper, strengthened oxygen delignification of NaOH-AQ pulp of fast growing poplar with low kappa number (Kappa number 13.5, viscosity 851ml/g, brightness 37%ISO) was introduced. By changing different conditions of strengthened oxygen delignification: alkali dosage, temperature, time, oxygen pressure and assistant agent, etc., and detecting and analyzing the pulp kappa number, viscosity, brightness and delignification of the lignin after strengthened oxygen delignification, conditions better suitable for strengthened oxygen delignification of NaOH-AQ pulp was obtained: pulp consistency 10%, alkali dosage 2.5%, H2O2 dosage 3%, MgSO4 dosage 0.5%, oxygen pressure 0.6Mp, temperature 100°C, time 60min; under the conditions, the brightness of the pulp reached 77.2%ISO , pulp viscosity was 748ml/g, the pulp yield was 95%. This provided an experimental and feasible reference for TCF bleaching of NaOH-AQ pulp of fast growing poplar with low kappa number.

Prebleaching of eucalypt kraft pulp with OP stages: Effect of an acid pretreatment or chelation step

TAPPI Journal ◽  
2012 ◽  
Vol 11 (6) ◽  
pp. 31-38
Author(s):  
TATIANA M. PÓVOAS ◽  
DINA A.G. ANGÉLICO ◽  
ANA P.V. EGAS ◽  
PEDRO E.G. LOUREIRO ◽  
LICÍNIO M. GANDO-FERREIRA ◽  
...  
Keyword(s):  
Eucalyptus Globulus ◽  
Comparative Evaluation ◽  
Kraft Pulp ◽  
Kraft Pulps ◽  
Acid Pretreatment ◽  
High Brightness ◽  
Pulp Viscosity ◽  
Brightness Reversion

We conducted a comparative evaluation of different treatments for the bleaching of eucalypt kraft pulps beginning with OP stages. The treatments tested were (1) an acid chelation stage with DTPA (OQP sequence); (2) a hot acid stage (AOP sequence); and (3) a chelant addition into the alkaline oxygen stage ((OQ)P and A(OQ)P sequences). The latter strategy was also studied for environmental reasons, as it contributes to the closure of the filtrate cycle. The OQP sequence leads to the highest brightness gain and pulp viscosity and the lowest peroxide consumption caused by an efficient metals control. Considering that the low biodegradability of the chelant is a problem, the A(OQ)P sequence is an interesting option because it leads to reduced peroxide consumption (excluding OQP) while still reaching high brightness values and similar brightness reversion to OQP prebleaching, with only a viscosity loss of 160 dm3/kg. Therefore, a hot acid stage could be considered when a separate acid Q stage is absent in a prebleaching sequence of Eucalyptus globulus kraft pulps involving OP stages.

Genetic control of kraft pulp yield in Eucalyptus globulus

2010 ◽  
Vol 40 (5) ◽  
pp. 917-927 ◽  
Author(s):  
Desmond J. Stackpole ◽  
René E. Vaillancourt ◽  
Geoffrey M. Downes ◽  
Christopher E. Harwood ◽  
Brad M. Potts
Keyword(s):  
Genetic Control ◽  
Eucalyptus Globulus ◽  
Kraft Pulp ◽  
Near Infrared ◽  
Genetic Correlations ◽  
Basic Density ◽  
Pulp Yield ◽  
Narrow Sense Heritability ◽  
Selection Gradients ◽  
Economic Worth

Pulp yield is an important breeding objective for Eucalyptus globulus Labill., but evaluation of its genetic control and genetic correlations with other traits has been limited by its high assessment cost. We used near infrared spectroscopy to study genetic variation in pulp yield and other traits in a 16-year-old E. globulus trial. Pulp yield was predicted for 2165 trees from 467 open-pollinated families from 17 geographic subraces. Significant differences between subraces and between families within subraces were detected for all traits. The high pulp yield of southern Tasmanian subraces suggested that their economic worth was previously underestimated. The narrow-sense heritability of pulp yield was medium (0.40). The significant positive genetic correlation between pulp yield and diameter (0.52) was at odds with the generally neutral values reported. The average of the reported genetic correlations between pulp yield and basic density (0.50) was also at odds with our nonsignificant estimate. Pulp yield of the subraces increased with increasing latitude, producing a negative correlation with density (–0.58). The absence of genetic correlations within subraces between pulp yield and density suggests that the correlation may be an independent response of the two traits to the same or different selection gradients that vary with latitude.

scholarly journals Consequences in a softwood kraft pulp mill of initial high alkali concentration in the impregnation stage

2019 ◽  
Vol 34 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Elisabet Brännvall ◽  
Ida Kulander
Keyword(s):  
Kraft Pulp ◽  
Pulp Mill ◽  
Alkali Concentration ◽  
Pulp Yield ◽  
Kraft Pulp Mill ◽  
White Liquor ◽  
High Initial Concentration ◽  
Softwood Kraft Pulp ◽  
High Alkali ◽  
Energy Balances

Abstract Impregnation with high initial concentration is fast and efficient, leading to a homogeneous delignification in the subsequent cook, resulting in improved screened pulp yield. To obtain high initial alkali concentration, the white liquor flow needs to be significantly increased. The moisture content of the wood chips and the alkali concentration of the white liquor limit the initial alkali concentration of the impregnation liquor that can be reached. It is therefore of interest to evaluate the possibility to implement high alkali impregnation (HAI) industrially and the consequences this would have on the mill system. The effect of HAI on mass and energy balances in a kraft pulp mill has been studied using mill model simulations. The sensitivity to disturbances in important parameters for process control has been compared to impregnation scenarios used industrially. It was shown that high initial alkali concentration can be achieved on industrial scale by increased white liquor flow. HAI has a positive effect on recovery flows and reduces the need for make-up chemicals. The HAI concept is less sensitive to variations in process parameters, such as chip moisture and white liquor concentration, thus diminishing the risk of alkali depletion in chip cores.

scholarly journals Chemical composition and fiber properties of fast-growing species in Latvia and its potential for forest bioindustry

2017 ◽  
Vol 66 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Inese Sable ◽  
Uldis Grinfelds ◽  
Laura Vikele ◽  
Linda Rozenberga ◽  
Dagnija Lazdina ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Kraft Pulp ◽  
Lignin Content ◽  
Lodgepole Pine ◽  
Pulp Yield ◽  
Fine Content ◽  
Fast Growing ◽  
Pulp Fibres ◽  
Global Energy Supply ◽  
Fast Growing Species

AbstractBioenergy, including energy from wood, currently provides about 9–13% of the total global energy supply. Every fibre of fast-growing wood has a value for its potential use as a material in both pulp and paper and wood chemical industries. The aim of this study was to assess the chemical composition and fibre’s properties of fast-growing species in Latvia – aspen, hybrid aspen, lodgepole pine, poplar and willow. Results showed a variation of cellulose, lignin, extractives and ash contents among the species. Kraft pulp yield and amount of residual lignin were measured and properties of pulp fibres determined. Form factor and fine content in pulp were measured. Poplar and aspen wood had the highest content of cellulose, while lodgepole pine had the highest lignin content in wood and the longest kraft pulp fibres. Willow had 20% of fines in pulp. Individual results suggest the most suitable application of each species.

MEA/water/AQ-pulping of wheat straw

Holzforschung ◽  
2009 ◽  
Vol 63 (5) ◽  
Author(s):  
Sahab Hedjazi ◽  
Othar Kordsachia ◽  
Rudolf Patt ◽  
Andreas Kreipl
Keyword(s):  
Wheat Straw ◽  
Total Yield ◽  
Strength Properties ◽  
Kappa Number ◽  
Chemical Recovery ◽  
Oxygen Delignification ◽  
Cooking Temperature ◽  
Recovery System ◽  
Environmentally Sound ◽  
High Yields

Abstract Annual plant pulping is faced with serious challenges. Traditional pulping processes with bleaching in chlorine based sequences and without appropriate chemical recovery system cannot be tolerated anymore. Alternative pulping processes with non-conventional chemicals, such as organic solvents, e.g., monoethanolamine (MEA), might be suited for an environmentally sound process with a closed mill system. Thus, pulping of wheat straw with MEA as the main delignifying agent was investigated in comparison to soda and soda/AQ pulps as references. The main focus was placed on reduction of the cooking temperature in order to avoid heat-induced MEA degradation. The temperature was reduced stepwise from 165°C to 130°C. At 150°C, a sufficient delignification was achieved. MEA was partly substituted by water and the resulting decrease of the delignification rate could be compensated by addition of anthraquinone (AQ). After optimization of the process, a pulp with a kappa number of 17 was obtained at a total yield of 56% based on o.d. straw. This pulp was selected for bleaching. Both, O/Q/OP/DQ/P (“ECF light”) and O/Q/OP/ZQ/P (TCFZ) bleaching were applied. NaOH was substituted by MEA as alkali source in the oxygen delignification stage. Up to 50% delignification rate was achieved under these moderate conditions. In the ECF light bleaching sequence, a brightness of 80% ISO was reached at a kappa number level below 3. In TCFZ bleaching, an even somewhat higher brightness was achieved at a kappa number level below 1. A yield of fully bleached screened pulp of around 50% (based on o.d. straw) was obtained. The strength properties of the MEA pulp were improved after bleaching. ECF bleaching resulted in slightly better pulp strengths than the TCFZ alternative. MEA forms in combination with water and AQ a very selective pulping system providing effective delignification and maintaining extremely high yields. MEA/water/AQ pulping should be regarded as a serious, environmentally friendly alternative to soda or soda/AQ pulping to produce high-quality pulp from wheat straw.

scholarly journals Reversibility in radionuclide/bentonite bulk and colloidal ternary systems

2015 ◽  
Vol 79 (6) ◽  
pp. 1307-1315 ◽  
Author(s):  
Nick Sherriff ◽  
Ragiab Issa ◽  
Katherine Morris ◽  
Francis Livens ◽  
Sarah Heath ◽  
...  
Keyword(s):  
Rate Constant ◽  
Ethylenediaminetetraacetic Acid ◽  
Average Rate ◽  
Ternary Systems ◽  
Dissociation Rate ◽  
Convincing Evidence ◽  
Dissociation Rate Constant ◽  
Stage Process ◽  
Slow Dissociation ◽  
The Eu

AbstractTernary systems of 152Eu(III), bulk bentonite and ethylenediaminetetraacetic acid (EDTA) ([Eu] = 7.9 × 10–10 M; pH = 6.0–7.0) have been studied. Without EDTA, there was slow uptake in a two-stage process, with initial rapid sorption of Eu(III) (96%), followed by slower uptake of a much smaller fraction (3.0% over a period of one month). The reversibility of Eu(III) binding was tested by allowing Eu(III) to sorb to bentonite for 1–322 days. EDTA was added to the pre-equilibrated Eu bentonite systems at 0.01 M, a concentration that was sufficient to suppress sorption in a system where EDTA was present prior to the contact of Eu(III) with bentonite. A fraction of the Eu was released instantaneously (30–50%), but a significant amount remained bound. With time, the amount of Eu(III) retained by the bentonite reduced, with a slow fraction dissociation rate constant of approximately 4.3 × 10–8 s–1 (values in the range 2.2 × 10–8 – 1.0 × 10–7 s–1) for pre-equilibration times ≥7 days. Eventually, the amount of Eu(III) remaining bound to the bentonite was within error of that when EDTA was present prior to contact (4.5% ± 0.6), although in systems with pre-equilibration times >100 days, full release took up to 500 days. Europium interactions with colloidal bentonite were also studied, and the dissociation rate constant measured by a resin competition method. For the colloids, more Eu was found in the slowly dissociating fraction (60–70%), but the first-order dissociation rate constant was faster, with an average rate constant of 8.8 × 10–7 s–1 and a range of 7.7 × 10–7 –9.5 × 10–7 s–1. For both bulk and colloidal bentonite, although slow dissociation was observed for Eu(III), there was no convincing evidence for 'irreversible' binding.

Sign in / Sign up

Export Citation Format

Share Document