Nanofiltration membrane process system for deep recovery of waste alkaline liquor

Abstract

The invention discloses a nanofiltration membrane process system for deep recovery of waste alkaline liquor. The process system comprises a waste liquid tank, a nanofiltration membrane device and a filter liquid tank in sequential connection, wherein a material pump, a safety filter, a high-pressure pump and a circulation pump are sequentially arranged on a pipeline for connecting the waste liquidtank and the nanofiltration membrane device; the filter liquid tank is connected with a clear liquid outlet of the nanofiltration membrane device; a waste liquid discharging pipe is arranged on a concentration liquid outlet of the nanofiltration membrane device; a concentration backflow pipe connected with the waste liquid tank is arranged on the waste liquid discharging pipe; a concentration backflow valve is arranged on the concentration backflow pipe; a circulation pipe is arranged on the waste liquid discharge pipe positioned at the front end of the concentration back flow valve; the circulation pipe communicates with the pipeline arranged between the high-pressure pump and the circulation pump. During the operation, through the flow rate arrangement of the concentration backflow valve and the circulation pipe, the flow rate entering the nanofiltration membrane device per hour is enabled to be higher than that of the existing device, so that the goals of increasing the membrane layer flushing quantity, lowering the remaining probability of impurities such as separated out hemicellulose, resin and divalent ion complexes, and prolonging the service life of the nanofiltration membrane device are achieved.

Description

technical field [0001] The invention relates to a nanofiltration membrane process system for deep recovery of waste lye, in particular to a process system for recycling waste lye by using a nanofiltration membrane, and belongs to the field of waste liquid treatment in industries such as viscose fiber production and papermaking. Background technique [0002] In the viscose fiber production and papermaking industry, it is necessary to impregnate the pulp, and the treatment method is to dissolve the semi-fiber, resin and ash in the pulp in the lye at a certain temperature with a certain concentration of sodium hydroxide. and removed by pressing. However, after repeated use of these lyes, the content of semi-fiber, resin, ash, etc. will gradually increase, and when they reach a certain concentration (that is, commonly known as black liquor in the industry), they cannot be reused. In the industry, some enterprises adopt the method of directly discharging to environmental protect...

AI Technical Summary

Problems solved by technology

This method avoids the clogging of the roll-type nanofiltration membrane core to a certain extent and prolongs the service life of the membrane core, but it cannot fundamentally improve the recovery and treatment efficiency of waste lye

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