Issues related to pressure testing and leak checking after the installation of the concentrated sulfuric acid tank
Thread Content
Hello everyone, we have a 25m3 vertical atmospheric concentrated sulfuric acid storage tank that has been almost completely installed. Here’s the problem: after installation, I need to perform gas purging and leak testing on it. However, neither the sulfuric acid tank nor its associated components are equipped with pressure gauges. How can I use an air compressor to ensure that the pressure inside the tank remains at ≤0.1 Mpa? 2. After the gas purging for leak testing is completed, I plan to fill the system with water in order to check the stability of the entire sulfuric acid delivery system. But how can I ensure that there is no water left inside the tanks and associated pipelines after using water? Note: Our factory does not have equipment for heating the air. Please help, thank you
Also: The sulfuric acid tanks and pipelines in our company have all been lined with PTFE! ! ! ! ! ! !
First, leak testing is carried out before lining with PTFE; once it passes, the area is dried and rust removed before lining it. After the equipment is lined with PTFE, a leak detector is used to check the quality of the lining. As for the lack of a pressure gauge for measuring pressure, I’ve heard before that a pressure gauge is welded onto existing pipes and then removed after the tests are successful; I’m not sure if this is indeed done in actual production. Many devices do not have pressure gauge ports, but pressure testing is still required; this is not an isolated issue, and there must be a solution.
When purging, opening the container allows for purging without any pressure issues. After filling with water, drain it completely and then purge and dry it with nitrogen.
There is no nitrogen in the plant area! Using air is mainly for pressure testing and leak detection; if the opening is left unsealed, it’s almost impossible to detect leaks
In principle, pressure testing and leak checking should be carried out before lining with PTFE, but due to time pressures and the fact that we operate under near-atmospheric pressure, such testing was not done prior to lining with PTFE! Only after the PTFE lining is completed do we use a leak detector to check the quality of the lining; we don’t have such equipment, so I’m unable to conduct tests. Therefore, I can only ask the other party for an \"Anti-corrosion Quality Certificate\" as a solution! For ordinary pipelines, a pressure gauge can be welded to them and then removed after testing; however, when PTFE is used as a lining, welding at high temperatures will result in temperatures exceeding 300°C, and at such temperatures the PTFE may peel off or become ineffective. Therefore, welding or cutting operations on pipelines or tanks with PTFE linings are not allowed.
Using air for leak testing is a type of airtightness test; whether it is necessary depends on the medium being used. If it is at atmospheric pressure, water can be used for leak testing, while for small containers, air can be filled inside them and then submerged in water to check for leaks. If the hydrostatic test specifies a value below 0.1 MPA, such as 0.05 MPA, a pressure gauge must be used.
1 Install a pressure gauge on a tee upstream of the sulfuric acid feed line. For the water test, after completing the test, purge the pipeline and then run a small amount of dilute sulfuric acid through it.
? What is the purpose of using dilute sulfuric acid in pipelines? If dilute sulfuric acid is used to flow through the pipeline, will a exothermic reaction still occur if I then fill it with concentrated sulfuric acid?
There’s no need to go through such trouble. What is the wall thickness? Check it with a spark detector; if no sparking occurs, that’s fine. There’s no need to perform pressure testing on containers of 25 cubic feet.
After lining it with PTFE, I specified in our technical agreement that he carry out positive and negative pressure tests as well as spark tests! I am testing for water tightness and airtightness; my main concern is leakage at the connections where the nozzles meet the flanges