What are the criteria for acceptable pumice corrosion?
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The pumice used in our equipment was previously used as a raw material for ethylene; now it is required to be used in the production of refined products. Therefore, the corrosion resistance level of this pumice needs to reach 1a or 1b, yet in our case its corrosion resistance often reaches 3a (even a level of 2a is considered unacceptable). It is said that 1A is very close to 3A, while 1B is further away from 1A; so it’s confusing – if 1B can meet the standards of 3A, then why can’t it meet them? Could someone explain to me what the order is for 1A, 1B, 2A, 2B, 3A, and 3B? This post was last edited by jilinzhengda on 2009-4-3 09:19.]
Corrosion of all types of gasoline refers to the corrosion of copper sheets; it denotes the condition of these sheets after being immersed in a gasoline sample for 4 hours in a water bath at 50 degrees Celsius. By comparing with standard color charts, corrosion is classified into 4 grades and 8 levels, with the severity increasing in the order: 1A, 1B, 2A, 2B, 3A, 3B, 4A, 4B. No noticeable discoloration of the copper sheet corresponds to grade 1A; as the discoloration increases, the grade rises gradually to 4, at which point the copper sheet is essentially black. According to national standards, only 1A is qualified. Corrosion resistance is a fundamental requirement for gasoline products. When used as a feedstock for ethylene, pumice must not only be free from corrosivity but also have an olefin content of less than 1% ； However, when used for blending, the olefin content is not controlled, but corrosion resistance must be satisfactory. You’ve only reached 3A, so you definitely fail. A level 3 color change is quite dark. This post was last edited by qlasd on 2009-4-3 11:07.]