Method for cleaning phosphoric acid delivery pipelines

Abstract

The invention discloses a method for cleaning phosphoric acid delivery pipelines. The method is implemented as follows: after respectively configuring a 5-8% sulfuric acid solution as an acid cleaning solution and a 4-10% sodium hydroxide solution as an alkaline cleaning solution, a transport pipeline, an acid supply pipe, a spare acid supply pipe, a cleaning solution configuration tank, a cleaning solution receiving tank, a solution supply pump and a solution return pump are connected together so as to form a circulatory cleaning system, and through starting the solution supply pump and the solution return pump, the circulatory cleaning can be performed in the pipes by a cleaning solution; and the alkali cleaning is performed firstly and then the acid cleaning is performed, or the acid cleaning is performed firstly and then the alkali cleaning is performed, and the acid cleaning solution and the alkaline cleaning solution are recycled respectively by using an acid cleaning solution recovery tank and an alkali cleaning solution recovery tank. The method disclosed by the invention is simple, quick, short in cleaning time, convenient in cleaning solution preparation, and low in cleaning cost; an effect of performing on-line cleaning on the phosphoric acid delivery pipelines can be achieved, and no damage is caused on the pipelines; after the phosphoric acid delivery pipelines are cleaned, the scale removal rate can be up to above 99%; and the method not only improves the cleaning efficiency, but also reduces the labor intensity of workers, and reduces potential safety hazards.

Description

technical field [0001] The invention relates to a cleaning method for a phosphoric acid delivery pipeline, which belongs to the technical field of chemical industry. Background technique [0002] In the production process of wet-process phosphoric acid, due to the complex composition of phosphate rock, when sulfuric acid reacts with phosphate rock to generate phosphoric acid, a large amount of impurities such as phosphogypsum, sodium fluorosilicate, potassium fluorosilicate and a large amount of metal oxides are also generated. . During the transportation of phosphoric acid, due to the long transportation pipeline, the temperature keeps dropping, and the solubility of impurities in phosphoric acid keeps decreasing. These impurities will be precipitated in the form of solid and stick to the pipe wall. Impurities accumulate on the pipe wall and become thicker, and the diameter of the pipe continues to decrease, which not only increases the resistance of the conveying equipmen...

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Problems solved by technology

Manual cleaning methods like this not only increase the labor intensity of workers and prolong the cleaning time, but also have some inherent disadvantages, such as poor operability, pipelines are not easy to disassemble and there are safety hazards, and the impact damage of external forces on the pipeline will shorten its service life. shorten etc.

[0003] Chinese patent application document 200810069067.5 discloses a method for descaling phosphoric acid delivery pipelines, which mainly uses sulfuric acid with a mass concentration of 2% to 6% and fluosilicic acid with a mass concentration of 4% to 8% to form a cleaning solution. The cleaning solution is added to the phosphoric acid delivery pipeline, and the temperature of the cleaning solution is controlled to 76-85°C. This solution shortens the cleaning time of the phosphoric acid delivery pipeline, but its disadvantages are that the scale removal rate is not high enough, and the cleaning method and power are unknown

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