Regarding oil products [sulfur content, Drabek test, copper strip corrosion]

Sulfur exists in oils in various forms, including hydrogen sulfide, thiol, thioether, disulfides, polysulfides, cyclic sulfides, thiophene and its derivatives, among which organic sulfides are the main ones. Copper sheet corrosion measures the degree of corrosion of machinery by oils ； The doctoral experiment is to measure thiol sulfur in petroleum products. In other words, sulfur compounds in oil are corrosive; however, if it’s not thiol sulfur, it won’t cause problems with the copper sheets, but the doctor approves it, and vice versa

What about the sulfur content? ? Our sulfur content has been a bit high recently, but the copper corrosion levels are within acceptable limits. Could you talk about the doctoral experiments? . .

What device produces the oil product? It would be sufficient to conduct a sulfur analysis to find out

The Doctor test is a qualitative analysis of the corrosive effect of thiol compounds in oils on machinery. (Only determines whether there is corrosion) Copper sheet corrosion is a qualitative analysis of the corrosion caused by oily contaminants on machinery. (It only determines whether corrosion has occurred; the levels here are classified in detail – you can look up more information on Baidu.) Thiol sulfur analysis involves the quantitative analysis of thiol compounds in oil products. (It only determines the amount of thiolic sulfur in the oil.) There are many relevant resources available on forums and the Internet that can be referenced: http://www.doc88.com/p-274339485082.html https://bbs.hcbbs.com/thread-931335-1-1.html

Is there a clearer answer? . . The sulfur content won’t go down; copper corrosion – the doctor’s tests are all satisfactory. . . In which direction should the analysis be carried out! ? ?

It’s best for you to upload your test results so that others can analyze them for you.

In recent years, the significant growth of the demand market, the influx of large amounts of foreign crude oil, the dual demands for fuel and chemicals, as well as the subsequent research on catalyst modifications, have all contributed to the rapid development of catalytic cracking technology in our country. Between CPP and FCC, there has been a great deal of innovation and competition; among them, the technology related to these catalysts stands out as the most advanced. However, as the target products are more finely divided, the degree of reaction (cracking) increases accordingly, resulting in a higher sulfur content in catalytic gasoline. The conventional three standard testing methods—acid-base reaction, the Drabek test, and copper sheet corrosion—are inevitably insufficiently comprehensive; similarly, for refined desulfurization, simple pre-alkaline washing along with thiol oxidation deodorization using cobalt as a catalyst is also inadequate. Most failures in acid-base reactions are caused by the presence of alkali ； The Doctor test is primarily used to detect the presence of active sulfides in oils [hydrogen sulfide and thiols]. Hydrogen sulfide is completely reacted away; if it remains, it must be due to a high level of thiols ； Copper sheet corrosion is primarily used to determine whether the oil contains active sulfides and elemental sulfur that can corrode metals; if the thiol content is within acceptable limits but copper sheet corrosion remains unacceptably high, it may be caused by elemental sulfur. Carbonyl sulfides and thioethers dissolved in oils are undoubtedly more stable structurally, and will not affect the results of the Drayton test and copper strip corrosion tests. If it is qualified, it indicates that the thiol is satisfactory; if it is unqualified, it does not necessarily mean that the thiol is defective. Furthermore, although small-molecule thioethers also have a strong odor, traditional deodorization refers only to the removal of mercaptans. Oxidizing mercaptans to disulfides merely reduces their concentration in the oil, but it does not change the total sulfur content. Such a high total sulfur level is unacceptable, whether the oil is used as a raw material for further processing or as fuel oil; therefore, the ultimate solution is to use low-sulfur crude oil or to carry out hydrorefining.

There is no lab report with a full analysis. There are only a few very simple ones. S content: 8-12; copper corrosion grade: 1A; passed the Dr. test; no water-soluble acids or bases.

Thanks, bro, for your generous help. This of mine is not gasoline with a catalytic device; it’s alkylated sulfuric acid gasoline. At the beginning of operation of the unit, the reactor was indeed alkali-washed as well as water-washed. Now there is doubt that the washing is not thorough enough. But it took less than a day for the sulfur content to drop from over 200 to over 50. It took a little over a day to go from over 50 to in the teens. It has now stabilized at less than 10, but it’s still quite high, around 8-9.