Pulping method with zero discharge of sewage water

A zero-emission, pulping technology, applied in the field of papermaking and pulping, can solve the problems of high operating costs and large investment in alkali recovery technology, and achieve the effects of saving investment, high yield of finished pulp, and high washing and bleaching efficiency.

Inactive Publication Date: 2008-07-16
CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problems of huge investment and high operating costs in the existing alkali recovery technology, and to provide a new technology for the treatment of black liquor and sewage in the pulping process of soda or soda zero residual alkali cooking, so that the pulping process not only has no sewage Discharge, also because black liquor is used for producing alkali lignin or lignin sulfonate, black liquor and sewage treatment have produced economic benefit, the present invention is not limited by papermaking scale

Method used

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  • Pulping method with zero discharge of sewage water
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Examples

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Comparison scheme
Effect test

Embodiment 1

[0037] The flow process is shown in Figure 1. In 2000kg of crushed and dust-removed reeds, add 700L of sodium hydroxide solution with a temperature of 80°C and a concentration of 10%. Add the catalyst under stirring. After stirring evenly, add it to the cooking pot for cooking. The cooking pressure is 0.4-0.8Mpa, the cooking time is 2 hours, the slurry concentration is controlled at 20-45%, and the mass dosage of the catalyst is 3.1%, wherein anthraquinone is 0.1%, and methanol is 3%. After cooking, the pulp first passes through three twin-screw extruders for three-stage serial countercurrent high-concentration extrusion, and the supplementary water is added by the last twin-screw extruder, and the amount of water added is 4-5m 3 / ton of pulp, the black liquor obtained by extruding the slurry from the last twin-screw extruder is returned to the second twin-screw extruder, and the black liquor obtained by the extrusion of the first and second twin-screw extruders is combined (...

Embodiment 2

[0039] See Figure 1 for the flow process. Add 700L of sodium hydroxide solution with a temperature of 80°C and a concentration of 12% to 2000kg of broken and dust-removed cotton stalks. Add the catalyst under stirring. After stirring evenly, add it to the cooking pot for cooking. . The cooking pressure is 0.4-0.8Mpa, the cooking time is 3 hours, the slurry concentration is controlled at 20-45%, the catalyst mass consumption is 3.15%, wherein the oxygen chlorine is 0.15%, and the methanol is 3%. After cooking, the pulp first passes through three twin-screw extruders for three-stage serial countercurrent high-concentration extrusion, and the supplementary water is added by the last twin-screw extruder, and the amount of water added is 4-5m 3 / ton of pulp, the black liquor obtained by extruding the slurry from the last twin-screw extruder is returned to the second twin-screw extruder, and the black liquor obtained by the extrusion of the first and second twin-screw extruders is ...

Embodiment 3

[0041] The process is shown in Figure 1. In 2000kg of crushed and dedusted poplar chips, add 700L of a cooking agent solution with a temperature of 80°C and a concentration of 15%, add the catalyst under stirring, stir evenly, and then add it to the cooking pot for cooking. The cooking pressure is 0.4-0.8Mpa, the cooking time is 2 hours, the slurry concentration is controlled at 20-45%, and the mass dosage of catalyst is 4.15%, of which chlorine oxygen is 0.15%, methanol is 3%, and urea is 1%. The cooking agent is a mixture of sodium sulfite and sodium hydroxide at a ratio of 4:1. After cooking, the slurry is firstly extruded through three twin-screw extruders in series in three stages of countercurrent high-concentration extrusion, and the supplemented water is extruded by the last twin-screw extruder. Added by machine, the amount of water added is 4-5m 3 / ton of pulp, the black liquor obtained by extruding the slurry from the last twin-screw extruder is returned to the seco...

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Abstract

The invention discloses a pulp making method for discharging sewage thoroughly which includes the following steps: pulping material, steam cooking agent and catalyst are mixed evenly and put into a spherical digester and the mixture is cooked by steam; the cooked material is squeezed by passing through a plurality of twin-screw extruders connected in series so as to extract black liquid and obtain the pulp material, and the black liquid obtained from the last twin-screw extruder is squeezed sequentially after returning to the former twin-screw extruder, while the black liquid obtained from a first and a second twin-screw extruders is merged straightly, and the merged black liquid is concentrated and dried to obtain alkali lignin and or lignosulfonate; the pulp material is delivered into a twin-screw rubbing and kneading pulper, the polyester washing is carried out in multiple-section series while the pulp is grinded, or the polyester washing is carried out in multiple-section series and bleached in multiple-section series, the washing water is returned to the washing process in the former section, and finally the residuary black liquid is obtained, that is the washing water coming from the first washing process; then, the residuary black liquid is returned to the pulping material or the spherical digester; the pulp material is refined in a dual-disk refining machine by adding water, then a pulp plate is made after the refined pulp material enters a paper machine. Meanwhile, the removed water circulates to the dual-disk refining machine or other processes needing the water by the pure water treatment.

Description

technical field [0001] The invention belongs to the technical field of papermaking and pulping, and in particular relates to a technology for making the pulping process without sewage discharge. Background technique [0002] After alkaline pulping, a large amount of fiber and non-fiber raw materials and most of the alkaline substances are dissolved in the cooking liquid to become black liquor, which is the largest pollution source in the paper industry, and the pollution load can reach 90% of the total pollution load. At present, large-scale papermaking enterprises at home and abroad mostly use traditional alkali recovery technology to treat black liquor. This technology is more effective in reducing environmental pollution caused by the paper industry. However, the one-time investment of traditional alkali recovery technology is huge, and it generally takes The investment is tens of millions of yuan, and the daily operating costs are quite high. Therefore, many small and med...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C3/22D21C7/00D21C9/18D21D1/20D21C9/02D21C11/00D21C9/10
Inventor 晏永祥
Owner CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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