A cleaning method for inner tube scarring of single-tube preheater

Abstract

The invention discloses a method for cleaning scabs in the inner tube of a single-tube preheater of the present invention. When cleaning the scabs in the inner tube of a single-tube preheater used in the alumina production process, follow the steps below Cleaning, (1) flushing process, that is, first use a high-pressure water gun to inject high-pressure water from the inner tube of the first-stage casing of the single-tube preheater for 30 minutes, and then inject the high-pressure water gun from the single-tube preheater The inner tube of the last-stage casing is injected for 30 minutes; (2) Cleaning agent process cleaning, the prepared cleaning agent is used to clean the inner pipe of the single casing preheater in a circulating flow at a temperature of about 60°C; (3) Use compressed air to purge and clean the inner tube of the single-tube preheater. The invention not only has the advantages of simple operation, convenient use, and clean scarring, but also has the advantage of not causing corrosion or damage to the inner tube of the single-tube preheater.

Description

technical field [0001] The invention relates to a method for cleaning scabs on an inner tube of a single-sleeve preheater, and belongs to the technical field of cleaning the inner tube of a single-sleeve preheater for alumina production. Background technique [0002] The single-tube preheating-indirect heating and dissolution technology of the autoclave belongs to one of the advanced technologies in my country's alumina production industry. Scarring is inevitable. Since there is no backup equipment for the single-tube preheater in the production process, it must be cleaned during the planned maintenance process every time. The inner and outer pipes of the single-casing preheater are both made of seamless steel pipes. The inner pipe is a slurry channel and the outer pipe is a steam channel. Often, the scarring of the inner pipe is serious, especially in the high temperature section. At present, acid cleaning is mainly used to clean the inner tube scabs of the single-casing p...

AI Technical Summary

Problems solved by technology

At present, acid cleaning is mainly used to clean the inner tube scabs of the single-casing preheater. Because the acid concentration of the cleaning agent used in the acid cleaning in the prior art is too high, and the pickling time is too long, this is harmful to the single-casing preheater. The inner pipe of the heater and its connecting welds have relatively serious corrosion phenomena, especially when the dissolution system is restarted and the temperature rises to a certain value, alkali seepage will appear in some welds of the inner pipe, and some even cracks, resulting in Re-shutdown of the dissolution system

Therefore, the existing method of cleaning the scab in the inner tube of the single-tube preheater is still not ideal enough and cannot meet the needs of use.