mechanical pulp delignification process

Mechanical Pulp Delignification Process

Oxygen delignification process | pulp stone mill

Jul 28, 2015 · Oxygen Delignification is one of the most significant and well proven pulp bleaching process for ECF (elemental chlorine free) and TCF (total chlorine free) bleached pulp production. It is the first stage of the bleaching process; in this case oxygen and alkali are used to eliminate a portion of the residual lignin in the pulp after cooking.

Bleaching of stone pulp - Wikipedia

Lignin is the main source of color in pulp due to the presence of a variety of chromophores naturally present in the stone or created in the pulp mill. Bleaching mechanical pulps. Mechanical pulp retains most of the lignin present in the stone used to make the pulp and thus contain almost as much lignin as they do cellulose and hemicellulose.

Delignification - an overview | ScienceDirect Topics

Delignification selectivity is an important concept during pulping and bleaching operations where it is desired to remove lignin while retaining as much holocellulose as possible. Delignification selectivity is the ratio of lignin removal to carbohydrate removal during the delignification process. Although this ratio is seldom measured directly, it is measured in a relative manner by yield ...

CA2099828A1 - Delignification process for stone pulp ...

ABSTRACT A process for the delignification of a stone stone pulp process for the delignification of a stone stone pulp by means of an organic peroxyacid which comprises treating the unbleached pulp originating from the cooking operation with an aqueous solution of the peroxyacid whose organic content of hydrogen peroxide does not exceed 20% by weight of the peroxyacid.

Oxygen delignification - Valmet

Oxygen delignification can be carried out in different ways. Valmet’s way is to optimize the conditions in the OxyTrac system in order to remove more lignin than ever before. Our OxyTrac delignification process removes up to 65-70% of the remaining lignin after cooking. This result remains unchallenged.

US4462864A - Process for the delignification of unbleached ...

The invention relates to a process for the delignification of unbleached stone pulp, comprising the following stages: (a) oxidation of the unbleached pulp with a peroxide, in an alkaline medium with a % ratio of peroxide/pulp with respect to the Kappa index of said pulp which may vary between 0.01 and 0.1 and a pH kept at between 9 and 12, the said oxidation stage being followed by (b ...

What is Delignification? (with pictures)

Nov 06, 2019 · Delignification is the removal of the structural polymer lignin from plant tissue, so that it can be used for applications like making paper. The process primarily refers to the stone process for the removal of pulp from wood. There can also be done mechanically.


OXYGEN DELIGNIFICATION Introduction Oxygen delignification is a process between cooking and bleaching sequences, where part of the residual lignin left in pulp after cooking is removed using oxygen and alkali. Oxygen delignification is a direct extension to delignification in cooking. The targeted reactions are the oxidation of lignin and

Mechanical properties of pulp delignified by deep eutectic ...

Full Article. Mechanical Properties of Pulp Delignified by Deep Eutectic Solvents. Andrea Škulcová, a Veronika Majová, a Jozef Šima, b and Michal Jablonský a, * Mechanical properties were evaluated for pulp delignified by four deep eutectic solvents (DES).

Process for delignification of a lignin containing pulp

Wood pulp production processes operate with stone grinders (mechanical stone pulp) or with refiners (TMP), which defibrillate the stone by grinding after appropriate pretreatment (chemical, thermal or chemical-thermal). ... A process for delignification of a lignin containing pulp comprising the steps of .

A method for integrated optimization of chlorine dioxide ...

Full Article. A Method for Integrated Optimization of Chlorine Dioxide Delignification of Bagasse Pulp. Yongjun Yin, Xueping Song, Chongxin Li, and Shuangxi Nie *. Chlorine dioxide bleaching is an important component of elemental chlorine-free bleaching.

MetZyme® LIGNO™ - for Mechanical and Kraft Pulp ...

Enzyme product family for Mechanical and Kraft Pulp Delignification. ... In many suitable process settings, additional benefits – such as stone reduction, improved dewatering or improvement of pulp quality – are obtained using MetZyme® LIGNO™ solution.

Delignification of refiner mechanical pulps from Albizia ...

The results showed that 8% NaOH + Na 2 S gave high yields (around 60%) with strength properties almost equal to those of kraft pulp (yield 45%). The results were also better than those obtained in previous tests of delignification of refiner mechanical pulp using the soda process.

Pulp (paper) - Wikipedia

Thermomechanical pulp is pulp produced by processing stone chips using heat (thus "thermo-") and a mechanical refining movement (thus "-mechanical").It is a two-stage process where the logs are first stripped of their bark and converted into small chips. These chips have a …

Pulp Bleaching Technology - Princeton University

Pulp Bleaching Technology THE BLEACHING PROCESS Bleaching is the treatment of cellulosic fiber with chemicals to increase brightness (see box 4-A). Brightness may be achieved by either lignin removal (delignification) or lignin decolonization. Lignin remains a major constituent of pulp even after digestion by stone pulping. For example, kraft


Figure 21: Viscosity and brightness of pulp after different oxygen delignification process conditions (a) reaction time, (b) NaOH charge, (c) reaction temperature and (d) mechanical pretreatment mixing time.

Pulping Process - an overview | ScienceDirect Topics

The kraft process is the dominating pulping process, which accounts for almost 60% of all mechanical and stone pulp produced worldwide. In this process, pulp is produced by digesting stone chips at high temperature and pressure in a sodium hydroxide solution called white liquor to dissolve the stone lignin and other organic stone substances and ...

Selectivity improvement in oxygen delignification and ...

Apr 09, 2009 · A process to enhance delignification or bleaching in stone or mechanical pulps comprising generation of singlet oxygen as a separate step and subsequent transport of singlet oxygen to pulp to effect bleaching or brightening of the pulp.

Effect of light-delignification on mechanical, hydrophobic ...

Jan 17, 2018 · To improve the mechanical, hydrophobic and other properties of HMFM, HMFM before and after the light-delignification treatment were prepared via hot-pressing molding process.

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