Hot work on concentrated sulfuric acid storage tank
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This post was last edited by sunjl1981 on 2013-1-6 at 23:19. Today, during my inspection, I found that hot work was being carried out on a concentrated sulfuric acid storage tank without any gas analysis being conducted. When asked, the person performing the work said that gas analysis was not required when working on the concentrated sulfuric acid storage tank. I used to do this often, and nothing ever went wrong. Is it reasonable for everyone to do this? # + +
First: It makes no sense. Second: Never do this. No accident happening doesn’t mean everything is fine! ! ! Third: Sulfuric acid is a strong \"oxidizing agent\" that releases oxygen easily; performing operations involving fire in such conditions can easily lead to an \"explosion\"! ! ! ! !
Reply to 2# wangzhihou: Oxygen only acts as an oxidizer; it does not explode. When concentrated sulfuric acid reacts with iron, an oxide layer forms on the surface of the iron, preventing further oxidation. Furthermore, when concentrated sulfuric acid reacts with iron, no hydrogen is released; is this the reason why no accidents occurred during welding operations on tanks containing concentrated sulfuric acid in the past? For tanks containing dilute sulfuric acid or other acids such as hydrochloric acid, phosphoric acid, nitric acid, etc., a thorough welding analysis must be carried out before any welding work is done
This is very dangerous, but what if, for some reason, the sulfuric acid concentration is too low and reacts with iron to release hydrogen gas, along with oxygen!
It’s better to do an analysis. After all, safety comes first when it comes to insurance. Earlier on, I heard that some factory had an explosion while working with acids in tanks; I can’t remember exactly what kind of acid it was. Besides, theory is still somewhat different from reality – what if there are special circumstances?
1. A fire hazard analysis must be conducted for any work involving towers, tanks, or vessels; this is a principle that must be adhered to. 2. Although concentrated sulfuric acid does not produce hydrogen when reacting with iron, keep in mind that this is a maintenance task – the storage tank needs to be cleaned and purged. Once the sulfuric acid is diluted, it reacts with iron to produce hydrogen. 3. Safety means following the procedures step by step.
Any hot work on pipelines and storage tanks involving sulfuric acid is classified as Class 1 hot work; not only must a hot work analysis be conducted, but the area must also be properly purged. Just because nothing happened before doesn’t mean nothing will happen now.
It is essential to conduct an analysis before performing any welding work on storage tanks; this is required by safety regulations. Sometimes people tend to take chances, but the fact that nothing happens doesn’t mean there’s no risk. I remember last year a factory carried out welding work on a hydrochloric acid tank, and an explosion sent people flying to the roof
Generally, maintenance workers tend to want to save time and leave as quickly as possible; this can easily lead to accidents, after all, human life is of utmost importance. In such cases, it is necessary to report to the relevant authorities and prevent them from carrying out the construction.