Method for recovering alkali and organic substance from pomace and waste liquid

Abstract

The method for covering alkali and organic substance from pulp waste liquor includes the following steps: under the condition of that temp. is 20-60 deg.c and pressure is 1.5-3.0 MPa the pulp waste liquor is passed through the fixed membrane separation system to make separation to obtain the trapped liquor in which the concentration of organic substance is 90g / l and transmitted liquor containing sodium hydroxide, said transmitted liquor containing sodium hydroxide can be recovered, and can be used in pulp production, and the described trapped liquor containing organic substance can be evaporated and concentrated, and can be used for preparing products with high additional value after it is treated by means of modification process.

Description

technical field

[0001] The invention relates to a method for recovering sodium hydroxide and organic matter in pulp waste liquid. technical background

[0002] Chemical fiber is an important industrial and civil material, and the output of viscose fiber accounts for about 10%. Plant fiber, such as cotton fiber, is a main raw material for the preparation of viscose fiber. During the preparation of plant fiber, a large amount of waste liquid will be produced, such as cotton pulp waste liquid, which is the main source of pollution for enterprises, generally accounting for 10% of the entire pollution load. More than 80%. Cotton pulp waste liquid is the pulping wastewater formed by using cotton linters as raw material and similar to the alkaline papermaking cooking process. It is called cooking black liquor or black liquor, and contains a large amount of organic matter, residual alkali and inorganic impurities (see Table 1) .

[0003] project unit Concentrate...

Examples

Embodiment 1

[0020] Using waste liquid containing 0.2% wt of sodium hydroxide and 2.0% wt of organic matter with a chromaticity of 6000 times as the feed liquid, at an operating temperature of 45°C and a pressure of 2.5 MPa, after separation by nanofiltration membrane , the obtained permeate is used to replenish the cooking liquid, and the organic matter concentration of the obtained retentate is increased to 9.0%wt. The retentate is further concentrated by a multi-effect evaporator, and can be sold as a commodity.

Embodiment 2

[0022] Using waste liquid containing 0.5% wt of sodium hydroxide and 3.0% wt of organic matter with a chromaticity of 10,000 times as the feed liquid, at an operating temperature of 58°C and a pressure of 2.8 MPa, after separation by nanofiltration membrane , the obtained permeate is used to replenish the cooking liquid, and the organic matter concentration of the obtained retentate is increased to 10.0%wt, and the retentate is further concentrated by a multi-effect evaporator.

technical field

[0001] The invention relates to a method for recovering sodium hydroxide and organic matter in pulp waste liquid. technical background

[0002] Chemical fiber is an important industrial and civil material, and the output of viscose fiber accounts for about 10%. Plant fiber, such as cotton fiber, is a main raw material for the preparation of viscose fiber. During the preparation of plant fiber, a large amount of waste liquid will be produced, such as cotton pulp waste liquid, which is the main source of pollution for enterprises, generally accounting for 10% of the entire pollution load. More than 80%. Cotton pulp waste liquid is the pulping wastewater formed by using cotton linters as raw material and similar to the alkaline papermaking cooking process. It is called cooking black liquor or black liquor, and contains a large amount of organic matter, residual alkali and inorganic impurities (see Table 1) .

[0003] project unit Concentrate...

Examples

Embodiment 1

[0020] Using waste liquid containing 0.2% wt of sodium hydroxide and 2.0% wt of organic matter with a chromaticity of 6000 times as the feed liquid, at an operating temperature of 45°C and a pressure of 2.5 MPa, after separation by nanofiltration membrane , the obtained permeate is used to replenish the cooking liquid, and the organic matter concentration of the obtained retentate is increased to 9.0%wt. The retentate is further concentrated by a multi-effect evaporator, and can be sold as a commodity.

Embodiment 2

[0022] Using waste liquid containing 0.5% wt of sodium hydroxide and 3.0% wt of organic matter with a chromaticity of 10,000 times as the feed liquid, at an operating temperature of 58°C and a pressure of 2.8 MPa, after separation by nanofiltration membrane , the obtained permeate is used to replenish the cooking liquid, and the organic matter concentration of the obtained retentate is increased to 10.0%wt, and the retentate is further concentrated by a multi-effect evaporator.