Multi-level light alkali evaporating unit and mercerized light alkali recovery system

Abstract

The invention discloses a multi-level light alkali evaporating unit. The multi-level light alkali evaporating unit is characterized by comprising first to fourth level shell-and-tube heat exchangers and first to fourth level steam separators, wherein the first to fourth level shell-and-tube heat exchangers are sequentially connected through valves, the first to fourth level shell-and-tube heat exchangers are correspondingly connected with the first to fourth level steam separators in a one-to-one correspondence, a vaporized alkaline liquor in the shell-and-tube heat exchanger is conveyed to the corresponding steam separator to separate the steam and the liquid, the liquid separated by each level of the steam separator is conveyed back to the correspondingly connected shell-and-tube heat exchanger, the separated steam is conveyed to the next level of the shell-and-tube heat exchanger, and a concentrated alkali is output from the fourth level shell-and-tube heat exchanger. The multi-level light alkali evaporating unit increases the efficiencies of evaporation, concentration and recovery of the light alkali, greatly saves the energies, reduces the cost, is more efficient and energy-saving, and brings more benefits for an enterprise.

Description

technical field [0001] The invention relates to the printing and dyeing industry, in particular to a mercerized light alkali recovery system. technical background [0002] The current situation and requirements of mercerized light alkali recovery: [0003] In the traditional printing and dyeing production process, lye is the most consumed chemical in printing and dyeing enterprises, accounting for about 10% of the total production cost. Extensive use of caustic soda indirectly causes a large amount of alkali in the discharged sewage, which seriously affects the biochemical treatment of sewage and The reclaimed water in the later stage is reused. Among them, the alkali consumption in the mercerizing process accounts for more than 60% of the total alkali consumption, so the reasonable recovery and reuse of the mercerizing light lye has a profound impact and effect on the control of the processing cost of the enterprise and the treatment of wastewater [0004] At present, t...

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Problems solved by technology

[0005] In order to solve the problems of low evaporation efficiency and high cost in the current recovery of light alkali in the printing and dyeing industry, the present invention firstly provides a multi-stage light alkali evaporation equipment. The multi-stage light alkali evaporation equipment includes first-fourth-stage shells Heat exchanger, first-fourth-stage steam-water separator, the first-fourth-stage shell-and-tube heat exchangers are connected sequentially through valves, light alkali is input from the first-stage shell-and-tube heat exchanger, and lye is The tube-side flow of the shell-and-tube heat exchanger, steam flows in the shell-side of each shell-and-tube heat exchanger, and the first-fourth-stage shell-and-tube heat exchangers are connected one-to-one with the first-fourth-stage steam-water separator , the vaporized lye in the shell-and-tube heat exchanger is sent to the corresponding steam-water separator for vapor-liquid separation, and the liquid separated by each stage of the steam-water separator is sent back to the correspondingly connected shell-and-tube heat exchanger, and the separated The steam is sent to the next shell-and-tube heat exchanger, and the concentrated alkali is output from the fourth-stage shell-and-tube heat exchanger

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