Brief introduction
Naphthenic acid is an organic acid with saturated ring structure widely existing in crude oil. In the process of crude oil refining, this kind of acid usually leads to the corrosion of refining equipment and system pipelines, and is related to the total acid value of crude oil in the process of processing. When the acid value of processed crude oil is more than 0.2 mg KOH/g, acid corrosion will occur. When the S content of processed crude oil is more than 0.5% and the temperature of processed crude oil is between 200 and 400 C, acid corrosion will be aggravated. The higher the flow rate of feed oil, the greater the impact with metal surface and the existence of sulfides will accelerate the corrosion of acid to equipment. In the actual production of atmospheric and vacuum distillation units, the corrosion of oil transfer lines, elbows and flow limiting parts is particularly serious. At present, the average acid value of crude oil processed by many refineries in China is about 1.0. The corrosion damage of naphthenic acid to equipment has attracted great attention.
At present, traditional neutralizing inhibitors can not effectively prevent acid corrosion in high temperature environment. The corrosion damage of naphthenic acid on equipment not only harms equipment, but also has a serious impact on secondary processing equipment. Iron naphthenate is produced during naphthenic acid corrosion, which has a strong cleaning effect on metal surface. FeS is brought into secondary processing unit and causes serious harm to catalyst. If the total Fe content of hydrocracking feed oil exceeds the standard, the pressure drop of catalyst bed will increase and the operation cycle will be affected. The unit will have to shut down and skim its head, resulting in huge losses.
This product is a new generation of high-efficiency phosphorus-free film-forming corrosion inhibitor developed on the basis of in-depth study of the corrosion mechanism of naphthenic acid. It can directly protect the corrosion site and form a solid chemical protective film (completely different from the physical protective film of low-temperature film-forming corrosion inhibitor). The product has good stability at high temperature and can be effective. To reduce the corrosion of naphthenic acid and sulfide on system equipment and pipelines.
Performance and use
1. The film-forming performance at high temperature is good, and it still has strong corrosion inhibition effect at 400 C.
2. Several evaluation experiments show that it has good anticorrosive effect on many kinds of crude oil and can effectively prevent the corrosion of equipment by naphthenic acid and sulfide.
3. It is suitable for the anticorrosion of equipment and pipelines at high temperature of atmospheric and vacuum pressure in the processing of high acid value and high sulfur crude oil, especially for the second, third and bottom oil transfer lines.
Addition amount
According to the acid value of treated crude oil, the general dosage is 5-20 ppm.
Usage method
The self-produced diesel oil is diluted by 2-5 times or injected directly into the high temperature parts such as the second, third and bottom oil transfer lines.