Continuous multi-segment acid displacement washing technological method

Abstract

The invention relates to a continuous multi-segment acid displacement washing technological method, and belongs to the technical field of nitrocotton acid displacement technologies. The method comprises the steps that an acid-cotton mixture subjected to a nitration reaction enters a horizontal type pusher centrifuge to separate acid and cotton, a sieve plate of the horizontal type pusher centrifuge comprises a high-concentration waste acid separation segment and a displacement washing segment, and five-segment countercurrent displacement washing is conducted on the displacement washing segment. The method adopts the five-segment countercurrent displacement washing technology, the acid cotton residua acidity after acid displacement is conducted is controlled below 8%, the residual acidity is greatly lowered compared with a traditional three-segment acid displacement technology, the final concentration of the washing waste acid is high, the washing waste acid contains 18-22% of nitric acid and 47-53% of sulfur, waste acid treatment, separation and concentration increasing is facilitated, and the technological procedure and the operation are simpler and more convenient relative to theacid displacement technology with two centrifuges being connected in parallel.

Description

technical field [0001] The invention relates to a continuous multi-stage acid displacement washing process, which belongs to the technical field of nitrocellulose displacement technology. Background technique [0002] The acid displacement washing process in the production process of nitrocellulose is the key step to realize the separation of acid and cotton solid-liquid, and has a decisive effect on the consumption level of nitric acid and sulfuric acid in the production of nitrocellulose. The traditional washing process for acid displacement of nitrocellulose usually includes: ①The acid cotton mixture after the nitration reaction enters the bedroom pusher centrifuge to separate the acid cotton, and then sends it to the subsequent cooking and washing section for stabilization treatment and viscosity adjustment. Such processes exist The problem mainly has two aspects, one is that the residual acidity of the acid cotton after acid flooding is about 30% to 40%, the acid consum...

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Problems solved by technology

[0003] The technical problem to be solved by the present invention is: on the premise that the residual acidity of acid cotton can be lowered, a continuous multi-stage acid displacement washing process with simpler process flow and better economic efficiency can be provided, which can reduce the production of nitric acid from nitrocellulose , sulfuric acid consumption, and at the same time ensure a high concentration of waste acid for replacement and washing, which is convenient for the recovery and concentration of waste acid

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