Selection of degreasing agents
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These past two days, I have been reviewing the degreasing procedure for oxygen pipelines; based on the actual conditions on site, CCL4 is used for degreasing oxygen tanks. Upon checking the HG20202-2014 \"Specifications for the Construction and Acceptance of Degreasing Projects\", it was found that CCL4 is not specified as a degreasing agent. I checked the internet again and then found out that CCL4 is prohibited from being used as a cleaner. I’m only learning about this degreasing agent now, even though it was banned back in 2003. Sharing the file content with everyone. After all, it is explicitly prohibited by law. **Announcement by the General Administration of Environmental Protection on Banning the Use of Carbon Tetrachloride as a Cleaning Agent (Circular No. 69) ________________________________________ The depletion of the ozone layer is one of the global environmental problems. To protect the ozone layer, the international community established the Montreal Protocol on Substances that Deplete the Ozone Layer in 1987 (hereinafter referred to as the \"Protocol\"). Our country joined the Protocol (London Amendment) in June 1991. In accordance with the provisions of the Protocol, my country should gradually reduce and ultimately completely cease the production and use of ozone-depleting substances starting in 1999. The \"Plan for the Phased Outplacement of Ozone-Depleting Substances in China (Revised Version)\", approved by the State Council in 1999, set out the phasing-out plans and targets for ozone-depleting substances in relevant industries, and established an industry-wide approach to such outplacement. In accordance with the \"China’s Comprehensive Plan for Phasing Out Ozone-Depleting Substances in the Cleaning Industry,\" to ensure the elimination of ozone-depleting substance-based cleaning agents within the specified timeframe, it has been decided that the use of carbon tetrachloride (CTC) as a cleaning agent shall be prohibited nationwide starting from June 1, 2003. Relevant departments should actively supervise and assist enterprises in implementing these measures rigorously, to ensure the effective prohibition of CTC. Enterprises that violate the above provisions shall be punished in accordance with the law by the local environmental protection administrative authorities in conjunction with relevant departments. This is to announce. January 1, 2003
For small-scale degreasing, carbon tetrachloride is still used~~ Hehe~~
Well, our project here is a methanol production facility; it ranges from air separation and air compression to oxygen generation, and the oxygen pipelines have a diameter of DN600, with a total length of over 400 meters. I’m not sure about other places, but I have asked the construction party to use degreasers other than CCL4. Since the work is divided among 3 contractors, one of them handles the circulation process, while the other two use degreasers for degreasing. There is another question: for oxygen pipes that are not made of stainless steel, is it necessary to remove rust from their inner walls? If there is only surface rust inside the pipe, can degreasing be carried out directly?
Large and long pipes are degreased using steam, acid wash, or alkali wash solutions, or by soaking them in acid or alkali wash solutions and circulating the solution; small parts and accessories can be cleaned by soaking them in trichloroethylene. Don’t forget to conduct the degreasing test at the end!