Composite type sodium polysulfide corrosion inhibitor and preparation thereof

Abstract

The invention relates to compound type sodium polysulphide corrosion inhibitor, which is suitable for the hydrogenation cracking reaction effluent air cooler. The compound type sodium polysulphide corrosion inhibitor is formed by combining sodium polysulphide, benzotriazole and organic amine film forming agent, wherein, the organic amine film forming agent is the combination of one or more of sodium molybdate, sodium chromate and zinc sulfate. The product integrates complexing, dispersing, corrosion prevention and film forming into a whole, has good synergistic inhibition effect under the low temperature and the high temperature and has good corrosion inhibition on the corrosion of the sulfide and the prussiate, the corrosion rate is reduced obviously, the temperature at the air-cooled water outlet opening can be guaranteed effective not to rise, the temperature of the tube bundle is even, the current bias phenomenon can not be caused, and the protective film formed on the surface of the equipment is steadier.

Description

Technical field [0001] The invention relates to a composite sodium polysulfide corrosion inhibitor, which is suitable for use in an air cooler for the effluent of a hydrocracking reaction. Background technique [0002] There are a large amount of hydrogen sulfide, ammonia and a small amount of cyanide, chloride and other corrosive media in the process stream of the air cooler of the effluent of hydrocracking reaction. In the presence of water, a variety of corrosive systems are formed, especially the corrosive medium cyanide. , It also promotes other corrosion reactions. In order to inhibit the corrosion of cyanide to equipment, the American CHEVRON Research Company has developed an anti-corrosion and scale inhibitor, that is, sodium polysulfide is added to the corrosive medium in the presence of cyanide, so that the sodium polysulfide reacts with the wall or pipe wall first. A dense protective film of FeS is formed on the surface to protect the equipment or pipeline to a certain...

AI Technical Summary

Problems solved by technology

However, in hydrogenation and high-pressure air cooling, sodium polysulfide is easy to decompose into elemental sulfur when it meets air, which makes scaling on the mechanical seal of the high-pressure water injection pump seriously affect the service life of the high-pressure water injection pump, storage tank and pipeline, and the formed ferrous sulfide protective film Relatively loose, failed to achieve the expected anti-corrosion effect on the protective tube bundle

[0003] Chinese patent application 02117840.2 discloses a "special corrosion and scale inhibitor for surface evaporation and air cooling", which is compounded with zinc sulfate, acrylic acid-acrylic acid ester copolymer, hydroxyl 1-1-ethylene diphosphonic acid, and benzotriazole It is suitable for circulating water systems with high hardness and high alkalinity, and the anti-corrosion effect is not ideal under high temperature and the presence of cyanide