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Process for treating spent,waste, alkaline digestion liquid from paper pulping operations and product

A cooking liquid, liquid technology, applied in the field of l 156, can solve problems such as impracticality

Inactive Publication Date: 2000-09-27
BOUNTIFUL APPLIED RES CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is successful on a laboratory scale, but on an industrial scale the large amounts of organic liquid required make this method impractical

Method used

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  • Process for treating spent,waste, alkaline digestion liquid from paper pulping operations and product
  • Process for treating spent,waste, alkaline digestion liquid from paper pulping operations and product
  • Process for treating spent,waste, alkaline digestion liquid from paper pulping operations and product

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Treatment of concentrated kraft cooking liquor with polymer followed by acidification

[0047] After separation from the fibers on wash rolls, the kraft spent cooking liquor was transferred with a composition factor total organic carbon (TOC) of 7.9% and a pH of 12.3. The polymer solution is added in such an amount that the liquid contains about 30 ppm polymer at ambient temperature. The mixture is then acidified with sulfuric acid to form a solid precipitate consisting mainly of lignin which floats on the surface of the residual liquid in the form of a non-gelatinous, non-sticky coagulum. These precipitated solids are then easily separated from the clear liquid by filtration but not by sieving. Analysis showed a clear liquid fraction TOC of 2.15%.

Embodiment 2

[0049] Treatment of concentrated kraft cooking liquor with polymer and another surfactant defoamer prior to acidification

[0050] Cooking liquor from the same source as in Example 1 was transferred and the same amount of the same polymer solution was added simultaneously at ambient temperature, along with 2 parts of fatty acid per 1000 parts of liquor. After standing for 1 minute, slowly add sulfuric acid with a concentration of 50% to the liquid for 1 minute to acidify it to a pH value of 3.5-4.0. Similarly, lignin solids in the acidified liquor formed a non-gelatinous, non-sticky coagulum that floated on the surface of the residual liquor but was easily separated from the liquor portion on a 10 mesh screen. The clear liquid fraction is clear and almost colorless. Analysis showed a TOC of 0.17%.

Embodiment 3

[0052] Treatment of Dilute Kraft Cooking Liquor with Polymers

[0053] Again all the cooking liquid from the same source was removed, but diluted with an equal amount of tap water. The diluted liquid composition was approximately 7.5% solids and 3.9% TOC with a pH of approximately 12.3. At ambient temperature, the same polymer solution as in the preceding examples was added to the dilute liquid so that the amount of polymer in the diluted liquid was 30 ppm. After standing for 1 minute, 50% sulfuric acid was added to the mixture again for 1 minute to acidify it to a pH of 3.5-4.0. The lignin therein forms a non-gelatinous, non-sticky, suspended particulate solid fraction which is easily filtered from the remaining liquid fraction. The clear liquid is clear and almost colorless. Analysis showed a TOC of 0.80%.

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PUM

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Abstract

When a water-soluble surface active polymer agent is mixed with a cooking liquor, an alcaline cooking liquor is preferably mixed with a surface active antifoaming agent and coagulation accelerator before the alcaline cooking liquor is acidized or during the acidification of the alcaline cooking liquor. An inviscid grumous lignin solid particulate, which is easy to be separated and is not gelatinous, tends to float on a clear liquid part containing recoverable salts. A solid part and a liquid part are easy to be separated each other using a step of gravity separation.

Description

Background of the invention [0001] Field: The invention belongs to the field of papermaking, and in particular to the treatment of alkaline cooking liquors for the separation of lignin and other solid and liquid components from the liquid components of waste and spent cooking liquors formed from the production of pulp used in the papermaking process field. [0002] Description of the prior art: Papermaking requires a source of cellulose fibers. Common raw materials used as fiber sources are hardwoods, softwoods and annual plant sources such as wheat straw and straw, bagasse (processed sugarcane stalk), hemp and jute. Rag materials as well as recycled fibers can also be used. But wood is the main source of cellulose fibers for papermaking. [0003] Before use, wood or other raw materials should be treated to release the cellulose fibers. This operation is called "pulping". Currently, there are three main types of industrial pulping operations: mechanical, fully chemical an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D21/01B03D3/00C02F1/52D21C11/00D21C11/04D21C11/06
Inventor H·埃尔沙尔
Owner BOUNTIFUL APPLIED RES CORP