Evaporation pretreatment process method for alkaline peroxide mechanical pulp

Abstract

The invention provides an evaporation pretreatment process method for alkaline peroxide mechanical pulp, which comprises a waste liquor recovery process and an alkali recovery process, wherein in the waste liquor recovery process, filter water in the production process of the alkaline peroxide mechanical pulp is collected to a waste liquor intermediate pond, and in the alkali recovery process, collected waste liquor in the waste liquor intermediate pond is subjected to alkali recovery treatment. Before the alkali recovery treatment, the method also comprises the following evaporation pretreatment steps of: (a) performing pressure filtering on waste liquor, namely filtering the waste liquor in the waste liquor intermediate pond by a pressure sieve, discharging dregs formed during filtering to a dreg sieving pond, and discharging the filtered waste liquor to a waste liquor tower to enter the step (b); and (b) performing evaporation grading treatment on the filtered waste liquor by an evaporator, wherein heavily-polluted concentrated solution is discharged to a concentrated solution pond for alkali recovery treatment, mildly-polluted concentrated solution is discharged to a wood chip washing water tank to clean wood chips, and after being mixed with disk mill dilution water in a white water tower, white water generated during evaporation is discharged to a hot white water tank and enters a pulping system of the alkaline peroxide mechanical pulp. The evaporation pretreatment process method has the advantages of high alkali recovery efficiency and environment friendliness.

Description

Technical field [0001] The invention relates to the field of pulping, in particular to the treatment of waste liquid in the field of chemical mechanical pulp, and specifically refers to a process method for pretreatment of chemical mechanical pulp alkali recovery and evaporation. Background technique [0002] As the APMP (Alkaline Hydrogen Peroxide Mechanical Pulp) workshop generates a lot of waste water, waste residue, and waste gas during the production of chemical pulp, in order to protect the environment and save costs for the company, there are a series of services such as alkali recovery. In the pulping section, on the one hand, wastewater is treated to meet environmental protection requirements and discharged. In addition, alkali recovery also allows waste to be reused, which improves the economic benefits of the enterprise. [0003] At present, the chemical pulp alkali recovery treatment process is to directly enter the collected waste liquid into the alkali recovery treatm...

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Problems solved by technology

[0003] At present, in the alkali recovery process of chemical and mechanical pulp, the collected waste liquid is directly entered into the alkali recovery process. On the one hand, due to this method, there are many impurities in the waste liquid, mixed with a lot of slag, and most of the waste

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