Problems with pressure testing hydrocracking reactors
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Our new hydrocracking unit is about to start operation, and a leak test needs to be conducted before that. The standard options for the leak test are as follows: Option 1 – using air, at a temperature of 25°C and a pressure of 12 Mpa; Option 2 – using hydrogen, also at a temperature of 25°C and a pressure of 12 Mpa. Are both of these airtightness methods viable? If these two airtightness methods are used in old reactors, is that a problem? I would appreciate it if experts could share their insights
Test the seal with 12 MPa of hydrogen? Who gave me the courage? What to do if there are leaks? Who would dare to tighten them?
Air? ? ? ? ? For newly commissioned units, nitrogen is first used to ensure airtightness and displace all air from the system, after which hydrogen is used for the same purpose. Airtightness testing is carried out at different pressure levels as specified in the design; any leakage points are identified and recorded. The system is sealed only after the pressure has been reduced to normal levels; sealing under pressure is strictly prohibited
Airtight? All require an oxygen content of less than 0.5%, and it has to be raised to 12 MPa at once? Until the temperature reaches 93 degrees, the pressure must not exceed 1/4 of the design pressure. What kind of airtightness solution is this?
Air tightness is unlikely; it should first be made nitrogen-tight, and after that, hydrogen-tight
Bring the nitrogen to its maximum allowable level; once that is achieved, reduce the pressure to the highest level at which hydrogen can be introduced. Perform hydrogen displacement, and once the displacement is successful, raise the temperature to no more than 150 degrees. Perform airtightness testing at each stage, and conduct a pressure retention test. Since this is the first time the process is being carried out, both the pressure increase and the pressure holding phase can take some time; it will take at least 3 to 4 days to achieve hydrogen gas tightness. If you’re not confident in the device, you can also use an external device to create a nitrogen seal, though it’s more troublesome.
Air pressure testing is a great idea! The key is for the original poster to first think about how to obtain such 12MPa of compressed air! Unless you specifically get a special air compressor! It seems no one in China has done this yet! ! ! ! ! ! !