Novel papermaking black liquor treatment method and system

Abstract

The invention discloses a novel papermaking black liquor treatment method and a system. The method includes adding an industrial waste acid into papermaking black liquor sewage to perform an acid eduction processing, after the acid eduction, generating numerous lignin flocs in the sewage, separating the lignin flocs through step by step filtering of a filter tank, feeding a filter liquor after the flocs are separated into a coagulation flotation device, adding chemicals into the device under the pneumatic stirring condition to perform a coagulation, depositing to form flocs, adjusting the potential of hydrogen (pH) value of the sewage which is subjected to the coagulation flotation, and then enabling the sewage to enter into a biochemical system to be subjected to a biochemical treatment. According to the novel papermaking black liquor treatment method and the system, a novel pre-treatment technology is utilized, a lignin acid eduction process is modified, a stable and efficient operation can be achieved, a method of treatment of wastes with processes of wastes against one another is utilized, the treatment cost is lowered, lignin of industrial chemicals can be extracted from the discharged flocs, the resource recovery utilization of a papermaking black liquor can be achieved, the sustainable development of economy can be facilitated, numerous pollutants can be removed in a front-end pretreatment, the follow-up biochemical treatment pressure can be greatly reduced, and thereby the entire process can stably and efficiently operate.

Description

technical field [0001] The invention belongs to the field of sewage treatment technology, and in particular relates to a novel papermaking black liquor treatment method and system. Background technique [0002] The paper industry is a pillar industry in my country, and its current annual paper output is second only to the United States and Japan. Most manufacturers in my country use grass fiber as the main raw material for papermaking. According to relevant data, more than 70% of the pulping raw materials in my country's paper industry are taken from non-wood fiber raw materials such as straw and wheat straw. The sewage discharge of the pulp and paper industry accounts for about 10% to 12% of the total sewage discharge in the country. The high level of pollutants in the paper industry is related to the low concentration of the paper industry, the large number of small paper mills, and backward production technology. According to incomplete statistics, some small-scale pul...

AI Technical Summary

Problems solved by technology

Due to the complex composition of black liquor, it is not ideal to use a single method to treat it. The advantages of physical and chemical methods are direct and fast, but the cost is high and the sludge is difficult to dispose of. The biological method has the advantages of low treatment cost, simple operation and management, and high treatment efficiency. However, due to the difficult biochemical properties of lignin, the application of this method in papermaking black liquor has been greatly restricted.

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