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Method for producing oxidised lignin in kraft pulp mill

A technology of kraft lignin and kraft pulp, which is applied in the direction of oxidation waste liquid, pulping liquid regeneration, pulp by-product recovery, etc., and can solve problems such as delay

Pending Publication Date: 2021-09-10
ANDRITZ AG +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Small organic acids (formed during oxidation and residues of unwashed kraft lignin) can cause e.g. delays in cement hydration

Method used

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  • Method for producing oxidised lignin in kraft pulp mill
  • Method for producing oxidised lignin in kraft pulp mill
  • Method for producing oxidised lignin in kraft pulp mill

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach

[0023] According to one embodiment of the present invention, the method at least includes the following steps:

[0024] Separation of unwashed kraft lignin from kraft mills,

[0025] dissolving said unwashed kraft lignin in oxidized or unoxidized white liquor to obtain an alkaline lignin solution,

[0026] Under alkaline conditions, the lignin solution was oxidized using:

[0027] a)O 2 overpressure gas, and

[0028] b) during oxidation, the introduction of NaOH and / or oxidized white liquor as an alternative source of alkalinity,

[0029] processing said oxidized lignin using one-stage membrane filtration or a series of multiple filtration stages (membranes) to recover concentrated lignin, and

[0030] Recover and / or recycle sodium and other by-products.

[0031] Unwashed lignin is referred to in this paper by CO 2 The lignin obtained but not washed with sulfuric acid is precipitated. The high ash content of lignin does not hinder alkali-O 2 Oxidation, so pickling is n...

Embodiment

[0051] Alkali-O 2 oxidation. First, lignin is dissolved in oxidized white liquor (OWL) with or without 0.5-40 wt% NaOH, more preferably 5-25 wt% NaOH, to obtain a solution with a pH of 13.0-14.0. in with O 2 Before the reaction, adjust the temperature of the lignin solution to ≤100°C, the most suitable is 60-80°C. The lignin oxidation process uses O from the pressure system of a kraft pulp mill 2 gas. During oxidation, NaOH or OWL or white liquor (WL) is introduced into the reaction solution as an alternative source of alkalinity. The total effective alkali dosage, including OWL, NaOH and WL, is less than 65% by weight of lignin, most suitably less than 50% by weight. Oxidation is at or below 18bar O 2 under pressure. o 2 added to the reactor during the oxidation reaction. An example composition of an oxidized white liquor (OWL) sample is shown in Table 1.

[0052] Table 1

[0053]

[0054] A positive effect of the inventive concept is the reduction of electrosta...

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Abstract

According to an example aspect of the present invention, there is provided a method for producing an oxidised lignin based high performance surface active agent in techno-economically feasible manner within kraft pulp mill without interfering the main process.

Description

technical field [0001] The present invention relates to a process for the production of oxidized lignin in a kraft pulp mill in an industrially feasible manner. Background technique [0002] Dispersants are used in many processes and products to improve product processability and product characteristics / performance, and to reduce production costs. Anionic dispersants cover most of the dispersant market. Concrete plasticizers are anionic dispersants that disperse cement particles, allowing good workability of fresh concrete and ensuring good strength properties of the final product (mature concrete). Similarly, anionic dispersants are used for example in the preparation of paints and coatings which contain high levels of different inorganic pigments. Lignosulfonates from sulfite pulping are marketed as biobased concrete plasticizers and dispersants. Typically, lignosulfonates perform significantly lower than synthetic plasticizers / dispersants. Synthetic superplasticizer p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C11/00D21C3/02D21C11/04
CPCD21C11/0007D21C3/02D21C11/0057D21C11/04C08H6/00D21H11/04
Inventor 劳里·佩胡-莱顿宁宝琳娜·约戈德奥蒂·普卡卡特琳娜·肯帕伊宁安娜·卡里奥拉蒂娜·丽特安塔皮奥·维赫马斯
Owner ANDRITZ AG