Production method for effectively reducing emission of dust and sulfur dioxide in flue gas of alkali recovery furnace

Abstract

The invention discloses a production method for effectively reducing the emission of dust and sulfur dioxide in flue gas of an alkali recovery furnace. The production method comprises the following steps: (1) a black liquid ultra-concentration technology, wherein thickening crystallization effect is newly added to increase the concentration of a black liquid, and an ultra-thick combustion technology is adopted to change an alkali furnace air supply system and achieve stable and efficient combustion; (2) a dust remover technology, wherein a wet type electric dust remover is additionally arranged to cooperatively remove dust on the premise of a dry type electric dust remover so as to reduce the dust concentration in flue gas; and (3) a dilute white liquid desulfurization technology, whereina causticized dilute white liquid is added into the wet type electric dust remover to serve as a circulating liquid to absorb SO2 in the flue gas so as to further reduce the discharge amount of the SO2. According to the invention, the method meets the national alkali recovery boiler flue gas emission standard, wherein the SO2 emission concentration is not higher than 200 mg / Nm<3>, and the dust emission concentration is not higher than 20 mg / Nm<3>; and the SO2 and the dust achieve the purpose of ultralow emission after technical improvement, and good social and ecological benefits are achieved.

Description

【Technical field】 [0001] The invention relates to the technical field of alkali recovery, in particular to a production method for effectively reducing the emission of dust and sulfur dioxide in the flue gas of an alkali recovery furnace. 【Background technique】 [0002] In the kraft (alkali) pulping process, about 40-50% of the organic matter in the fiber raw material is dissolved in the cooking lye to become black liquor. The main components of these inorganic substances are sodium salts combined with organic substances, free NaOH, Na 2 CO 3 、Na 2 S, Na 2 SO 4 etc. Each ton of chemical pulp can produce 10m 3 The black liquor of around 1.2-1.7 tons in solid content is the source of pollution. The purpose of alkali recovery is to convert the sodium salt in the black liquor into NaOH, which is reused for cooking and continuously recycled, so as to reduce the consumption of alkali and reduce the pollution to waters. This is alkali recovery. [0003] With the emphasis on...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a production method for effectively reducing dust and sulfur dioxide emissions in the flue gas of the alkali recovery furnace, so as to solve the problem that the dust and sulfur dioxide emissions in the flue gas of the alkali recovery furnace are not up to standard. Wet electrostatic precipitator technology and dilute white liquor desulfurization technology effectively reduce dust and sulfur dioxide emissions

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