Hydrogen explosion in sulfuric acid pipeline causes pipeline rupture
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In a 60 kt/a sulfuric acid production system, a leak occurred in the welded pipe of the dry-suction anode protector, causing the acidity level of the circulating water to drop below pH 2. Upon discovery, the plant was shut down urgently for inspection and repair of the anode protection system. After removing the concentrated acid and water, an explosion occurred during the welding process to fix the leak, resulting in the destruction of a section of the concentrated acid pipeline at the far end of the pipeline as well as partial cracking of the casing of the conversion fan. Fortunately, no injuries were sustained. A reminder: the hydrogen gas produced by dilute sulfuric acid cannot be ignored. In such cases, how do manufacturers generally ensure proper air replacement to prevent hydrogen explosions, and how do they detect residual hydrogen in the pipelines?
Is the carbon steel used for your dilute sulfuric acid pipelines? ? ! ! Our company uses stainless steel everywhere
During shutdown, replace SO2 and SO3 before the temperature drops, then stop the fans; use clean N2 to maintain gas flow. After testing in the laboratory, use portable combustible gas detectors for monitoring on-site during construction
I missed it: In the case of cathodic protection, after draining the acidic water, it is necessary to rinse quickly with water until the pH level rises above 5. Then N2 should be introduced; once the combustible gas levels are within acceptable limits, an appropriate amount of N2 should be used for welding. A portable combustible gas detector should be used for monitoring during the construction process
Another point is that if it’s possible to use blind plates, do so to isolate the area; although the device belongs to Category C, when dealing with these areas where explosions could occur, it’s best to follow the procedures applicable to Category A devices
Cast components are used for the concentrated acid pipelines, while carbon steel is used for the water circuits
If anode protection is overlooked, after draining the acidic water, it is necessary to rinse quickly with water until the pH level exceeds 5; thereafter, N2 should be introduced. Once the combustible gas levels are within acceptable limits, an appropriate amount of N2 should be used for welding. A portable combustible gas detector should be used for monitoring throughout the construction process
It’s quite scary; special care must be taken when welding storage tanks and pipes
Lack of safety knowledge. Improper selection of equipment
The safety awareness is indeed weak, but there’s no issue with the equipment selection