Do static equipment such as stainless steel towers and heat exchangers necessarily require pickling?
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I would like to ask fellow sea industry professionals: is it necessary to carry out acid cleaning for static equipment such as stainless steel towers and heat exchangers? Are there any mandatory norms supporting this requirement?
Not all stainless steels require pickling; those with corrosion resistance requirements do. Some of what we do involves polishing stainless steel equipment that has strict cleanliness requirements. Specific requirements are outlined in HG/T 20584.
Static equipment such as stainless steel towers and heat exchangers does not necessarily require full acid cleaning; whether to carry out this process depends on the manufacturing process, the corrosivity of the fluids involved, and the design specifications. The core principle is that if there are contaminants on the surface that damage the passivation film (such as scale, weld spatter, iron ion contamination), they must be removed in order to restore corrosion resistance ； If the surface is clean and undamaged, the acid washing step can be omitted.
Now, basically all users of stainless steel static equipment require pickling. It’s a buyer’s market.
Does acid cleaning involve cleaning both the inner and outer surfaces, or only the outer surface of the equipment?
The equipment I designed doesn’t require polishing; it also requires pickling. If the buyer insists on it, then I’ll do it – after all, the cost has to be covered by someone.
Paragraph 4.2.3.7 of the Fixed Volume Gauge standards requires that pressure vessels or pressure components that require corrosion resistance or protection against corrosion shall undergo surface treatment, such as pickling and passivation
Indeed, times have changed; everyone now wants to eat refined grains.