Regeneration treatment method and device for black liquor of papermaking

Abstract

Disclosed is a regeneration treatment method of paper-making black liquor as well as an apparatus thereof, and the method comprises the steps that: firstly, the primary solid-liquid separation of mixture to a paper-making black liquor is implemented by adopting a belt filter press; secondly, the separated liquid enters a hollow-fiber membrane ultra-filtration separator through a retainer, and a hollow-fiber membrane adopting the chip type packaging is used to pump the solution by the negative pressure mode; thirdly, the separated filtrate is directly pumped into a reverse osmosis membrane system through a separating pump for concentrating a caustic soda solution; fourthly, the caustic soda solution is drained to a clear liquid storage tank after being concentrated by the reverse osmosis membrane, and the lye in the tank is tested to have the appropriate caustic soda concentration and can be directly pumped to the paper-making process for recycling; and fifthly, when the tested caustic soda has insufficient effective concentration, the lye is pumped to a causticization tank for causticizing treatment and then for recycling. The apparatus mainly comprises: a black liquor pond communicated with a paper-making production line, and the belt filter press used for the solid-liquid separation of lye in the black liquor pond; the hollow-fiber membrane ultra-filtration separator connected behind the belt filter press; and the clear liquid storage tank connected behind the reverse osmosis membrane which is connected behind the ultra-filtration separator, and the storage tank is connected with the causticization tank or directly connected with a lye scheduling pipeline as required.

Description

technical field [0001] The invention relates to a method for recycling and regenerating papermaking black liquor and a corresponding processing device, in particular to a method and device for regenerating papermaking black liquor mainly using hollow fiber ultrafiltration membrane-reverse osmosis membrane technology. Background technique [0002] At present, my country's paper industry generally adopts the following methods to process and reuse papermaking black liquor: [0003] 1. Solid-liquid separation, that is, the soil, sand, and residual fibers in the black liquor are separated from the liquid by a certain method. [0004] 2. Recycling or burning of solids. Some companies recycle part of the available fibers to produce low-grade paper and its products. Most companies send them directly to the boiler for combustion to concentrate the liquid separated before. This process does not matter whether the fiber Recycling or not, there is a staggering amount of energy consumpt...

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Problems solved by technology

[0004] 2. Recycling or burning of solids. Some companies recycle part of the available fibers to produce low-grade paper and its products. Most companies send them directly to the boiler for combustion to concentrate the liquid separated before. This process does not matter whether the fiber Recycling or not, there is a staggering amount of energy

[0008] From the above description, it can be seen that my country's paper industry has a huge energy consumption, and it is necessary to build a special workshop to maintain caustic soda recycling. The investment scale is large, the construction period is long, there is a large greenhouse gas emission, and a large land is required. Large area and a large number of dangerous goods are used, such as lime is highly corrosive, a large amount of heat is generated during the causticizing process, and dust pollution is large

[0009] Although there are the above-mentioned defects, because the papermaking black liquor contains a large amount of high-concentration caustic soda (20% to 30%), it cannot be discharged directly, and it also has a great impact on the cost of the enterprise. Therefore, papermaking enterprises can only choose to reuse the black liquor. effective caustic soda components

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