We all know that stainless steel pipes need to be installed before delivery Pickling passivation Processed.
However, there are times when users require re degreasing of pipes? As far as the pipeline is concerned, the more reasonable degreasing should be completed on site, that is to say, degreasing treatment should be carried out in the whole pipeline system after all pipelines are installed. Generally, the manufacturer will not be allowed to carry out degreasing treatment, so, what is the matter of requiring the manufacturer to degrease the pipeline?
With the increasing level of industrialization in China, as well as the vigorous development of petrochemical, natural gas, medical equipment, instrumentation, aviation, aerospace and other industries, the process requirements of stainless steel pipe are also higher and higher. For example, the cleanliness of the pipeline requires that there should be no free rust, large particles of dust, welding slag, grease and other impurities inside the pipeline.
Among them, the cleanliness requirement of oxygen pipeline is quite strict. Most of the oxygen pipelines transport oxygen with purity greater than 99.99%, which has high pressure and fast flow rate. If the internal cleaning of the pipeline cannot be guaranteed, the trace oil and metal ions in the pipeline may oxidize and collide with high-pressure pure oxygen, and produce electric spark, which will cause serious consequences and even lead to serious accidents.
Therefore, according to the process requirements, the newly-built equipment pipeline needs chemical cleaning method to remove the oil and other impurities on the internal pipe wall before the device is started. At the same time, the supplier will also be required to degrease the pipes.
The stainless steel oxygen pipeline produced by Zhejiang Yihong is used in the project
The world's largest coal to clean industrial gas project
Degreasing and cleaning steps of stainless steel oxygen pipeline: Water washing → manual wiping degreasing → water washing → compressed air (or nitrogen) purging.
Water flushing Small high pressure water cleaning equipment shall be used for flushing, and the pressure shall be controlled at about 0.6MPa to ensure that the impurities inside the pipeline are washed clean. The purpose is to remove the dust, sediment, metal oxide and other loose dirt in the pipeline.
Manual wiping degreasing Pour the cleaning and degreasing mixture into the cleaning basin, add it according to the proportion, mix it evenly, and then use it, and wipe it repeatedly. In the cleaning process, the cleanliness of degreasing cleaning fluid should be monitored. If the color of degreasing cleaning fluid becomes dirty, the existing degreasing solution should be drained out and the degreasing cleaning fluid should be re configured. The purpose is to remove all kinds of oil, graphite, antirust oil and other organic matters in the pipeline, so as to ensure the internal cleanness of the pipeline during installation and meet the requirements of equipment operation.
Water flushing After degreasing the pipeline, flush with a large amount of water. When the flushing water from the pipeline is clean, the water flushing can be finished. The purpose of water flushing after degreasing is to flush the degreased residual liquid in the pipeline.
Compressed air (or nitrogen) purging Use oil-free compressed air (or nitrogen) for purging, and dry the inside of the pipeline. After that, use clean plastic cloth to wrap up and seal the pipe or parts, so as to ensure the cleanness of the pipeline and avoid secondary pollution.
Degreasing acceptance method of stainless steel pipe The degreasing solvent specified in the design and the degreasing requirements shall be applied to the pipeline degreasing treatment. If it is not specified in the design, carbon tetrachloride can be used for degreasing to check whether the degreasing is qualified.
Degreasing stainless steel pipe
Degreasing stainless steel pipe used in Jiangxi Gaoan Jimin credible industrial gas project
After degreasing and cleaning, the pipeline shall meet the following requirements:
1) There should be no grease fluorescence when inspecting the inner wall of the pipeline with ultraviolet light with the wavelength of 320-380nm.
2) Clean and dry white filter paper shall be used to wipe the inner wall of the pipeline, and there shall be no oil stain on the paper.
3) Or use degreasing solvent to detect that the oil content does not exceed the requirements of the client.
4) Other relevant technical indexes proposed by the client.
Stainless steel oxygen pipe Chemical cleaning and degreasing process standardizes the construction process of oxygen pipeline cleaning and degreasing, greatly improves the internal cleanliness of oxygen pipeline, and is a reliable guarantee for safe and efficient operation of oxygen pipeline, which is worthy of attention and promotion by stainless steel pipe manufacturers.