How can the ethylene glycol pipeline be purged to meet the requirements for performing hot work?
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I’m seeking help from experts. For the plant modification, a 20% concentration ethylene glycol aqueous solution is used as a refrigerant, and piping work requiring hot work is necessary. How can it be made qualified to meet the conditions for hot work? I beg earnestly
First, replace with water. Second, purge with nitrogen. Third, blind flanges must be used to isolate both ends of the pipeline where work will be carried out. Fourth, remove all flammable materials from the area where work is to take place. Fifth, conduct a special risk assessment for the work. Sixth, obtain an work permit
Boss, do we need to use steam for displacement? How can one confirm that the pipes are clean after water displacement? What worries me the most right now is that there may be residues on the pipe walls, and problems could arise if heat is applied
If steam is available, using steam for purging is the best method of displacement. The pipeline must be disconnected from the system, and a blind flange should be installed on the side of the system that has been disconnected. After steam purging, the instrument is used for detection and analysis; once the results meet the requirements, welding work can proceed. Of course, the environment in which the welding will take place also needs to be verified. If it is a Class A workshop, the entire workshop must undergo proper gas displacement before welding work can begin. Firework use approval is required.
For this pipeline alone, empty it, rinse it with water, measure the concentration, and finally displace it with nitrogen to measure the oxygen content
Under no circumstances should steam be used for cleaning, as the liquid ethylene glycol turns into a gas at high temperatures, which can further trigger an explosion. The correct approach is to rinse with clean water, ensuring that the concentration of ethylene glycol in the liquid is less than 1%, while also checking that the concentration of flammable gases in the pipeline is below 0.5%
First, install blind flanges on both sides of the pipeline that is to be overhauled; place the blind flanges on the side of the pipeline that is subject to maintenance. Then wash the pipeline with clean water. It is ideal if the water can remain inside the pipeline without being drained; if drainage is necessary, use nitrogen for purging. The ethylene glycol content should be below 0.5% to be considered acceptable. Carry a portable combustible gas detector during the work; stop working immediately if an alarm is detected, and keep fire extinguishers available at the work site. Obtain a fire permit properly.