Acidic water pipeline grade issues
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Before the issuance of new standards such as GB50517-2010 and SH3501-2011, petrochemical pipeline grades were classified into four levels: A, B, C, and D. Pipelines carrying toxic or flammable media are classified as Class A and Class B ； Pipelines whose conveying medium is non-toxic and non-flammable are classified as Grades C and D. After the implementation of the new standards, they are divided into three categories: A, B, and C, with each category further divided into 5 tiers. In previous documents of Factory Zha, the old standard regulations were in effect at that time; the grades for acidic water, acidic gas, and lean (rich) amine solutions in the catalytic cracking unit were SHB. Now that new standards such as GB50517-2010 and SH3501-2011 are to be implemented, how should the grades of acidic water, acidic gas, and lean (rich) amine solutions be determined?
Design pressure? Temperature? It seems it should be based on the higher level.
Acidic gases can be defined as both SHA and SHB, since they are both flammable and toxic. Lean amine solution does not contain hydrogen sulfide; it is generally referred to as SHB. Rich amine solution, on the other hand, is associated with acidic gases. This definition mainly affects the detection ratio of pipelines
Should GC2 be considered based on its corrosivity?
It’s not GC1 or GC3; it’s GC2. This is as defined in GB/T20801. The hydrogen sulfide content in acidic water is generally low, so it does not qualify as a highly hazardous medium. It’s not GC1, and since it is toxic and flammable, it certainly isn’t GC3 either. Therefore, it is GC2. The prerequisite is that the pipe diameter must be ≥ DN50; those with a diameter < DN50 are not pressure pipes and can only be classified as SHA or SHB.
If high-pressure hydrogenation is used, the design pressure for acidic water exceeds 10 Mpa, in which case it falls under GC1