Stainless steel pipes for degreasing and cleaning

If there is rust or dirt on the inner surface of stainless steel pipe fittings, you can first use a round steel wire brush and cloth strips tied to thick iron wire or thin steel management rope, then penetrate the pipe and pull it back and forth. If it is a large-diameter pipe fitting, you can also use a winch to drag it back and forth. Brush, then rinse with steam or water, and then use compressed air or an exhaust fan to blow dry the inside of the pipe, and then it can be degreased.

When degreasing, first block one end with a plug, pour 15-20% of the pipe's volume of degreasing solvent into the pipe, if it is a curved stainless steel pipe, add an appropriate amount of degreasing solvent, then block the other end, and place it flat. Soak in a flat clean place or on a workbench with sleepers for 1-1.5 hours, and rotate the stainless steel pipe fittings every 15 minutes to the parts that need to be soaked. You can also immerse the pipes in a closed container filled with degreasing solvent. Degrease the inside of the long tip, then pour out the solvent in the tube, and use an exhaust fan to dry the inside of the tube, or use oil-free compressed air or nitrogen to dry it. You can also choose natural ventilation. In general, you must fully dry the tube.

After degreasing, it is necessary to check whether the degreasing condition of each stainless steel pipe is qualified. The inspection method is to use clean degreased gauze to make a plug, tie it to the wire, insert it into the needle and pull it to see if there is still grease. If necessary, a test is required. Degreased pipes need to be wrapped at both ends with degreased old cloth or plastic film to avoid recontamination of the inner surface of the stainless steel pipe.

When the installed stainless steel pipes need to be degreased, it is best to disassemble them into pipe sections without dead ends and then degrease them. Stainless steel pipe fittings that cannot be disassembled after installation must be degreased before installation, but it is necessary to ensure that they are not contaminated during and after installation.

After all the concentrated nitric acid pipelines and equipment of the concentrated nitric acid plant are installed, they can be directly pumped with 98% concentrated nitric acid for pickling. However, a pickling plan must be prepared before pickling. During pickling, the system must be divided according to the process flow. First clean with water, and then cycle with acid for 2-4 hours. Only after the analysis is qualified, the acid is directed to another system. When the acid contains grease and other organic matter exceeding 0.03% or the acid concentration is lower than 90%, it is necessary to replace the acid with a new one and discharge the waste acid to the underground tank. After passing the pickling process, materials need to be put into production in time to prevent dilution of concentrated nitric acid from corroding aluminum equipment and pipelines and affecting their use.