Preparation method of passivator for boilers in thermal power plants

Abstract

The invention discloses a preparation method of a passivator for boilers in thermal power plants. The preparation method comprises the steps of: weighing raw materials according to various components of the invention, 1) taking methanol, adding a moderate amount of water, uniformly stirring, sequentially adding hydrazine, ammonium benzoate and hexamethylenetetramine, and uniformly stirring, so that a solution is prepared; 2) taking a moderate amount of water again, adding seleninic acid and boric acid, uniformly stirring, sequentially adding sodium hydrogen sulfate, calcium sulfate, copper sulfate, ferrous chloride and sodium dodecylbenzene sulfonate under the condition that the next component is added after the previous component is dissolved, and after all the components are completely added, stirring for 5-15 minutes; and 3) adding the solution obtained in the step 1) into a solution obtained in the step 2), stirring for 10-20 minutes, adding water for determining a constant volume, and adjusting the pH value of the obtained product to 4-5.

Description

technical field [0001] The invention relates to the technical field of surface treatment, in particular to a preparation method of a passivating agent for a thermal power plant boiler. Background technique [0002] In the chemical cleaning of boilers, the passivation stage is the last link, and it is also a very important link. Regardless of whether inorganic acid or organic acid is used for boiler chemical cleaning, while removing various scales and corrosion products, it also converts the metal surface into an activated state, which is very prone to corrosion, causing secondary floating rust and pitting corrosion on the inner surface of the boiler And so on. If the passivation of the boiler is not done well after chemical cleaning, it is very easy to have abnormal phenomena such as the iron content in the boiler water continuously exceeding the standard and phosphate hiding. It can be seen that in the chemical cleaning of boilers, the passivation stage is a very importan...

AI Technical Summary

Problems solved by technology

According to the "Guidelines for Chemical Cleaning of Boilers in Thermal Power Plants", new high-temperature and high-pressure power plant boilers must be chemically cleaned before operation, and the average cleaning period for operating boilers is 5 to 10 years. According to this regulation, annual cleaning is equivalent to evaporation. The amount is about 5×10 5 For T / H high-temperature and high-pressure power plant boilers, with such a large amount of cleaning, if effective passivation protection cannot be carried out after pickling, the extremely active metal matrix will cause the boiler to quickly generate secondary floating rust, which not only affects the service life of the boiler, It also greatly prolongs the start-up time of the boiler, which will cause huge losses to the power company

In the "Guidelines for Chemical Cleaning of Boilers in Thermal Power Plants", there are also strict regulations on passivation measures after pickling, and nearly 10 passivation processes are recommended, but the protective effect of these passivation processes is not satisfactory , there are very few processes that can meet the requirement of not rusting within 20 days, let alone effective protection for boilers whose construction period is prolonged due to various reasons