Material of pipeline for hydrogen chloride and acetylene mixture
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In the design documents provided by the design institute, steel-lined PE was chosen as the material for the pipeline that carries a mixture of hydrogen chloride and acetylene. Although it has good strength, its cost is relatively high, and it is difficult to repair in case of corrosion or leakage. Therefore, I would appreciate it if experts could advise whether PVC+FRP could be used instead. Thank you. This post was last edited by yhpsxj on 2009-2-15 09:06.]
Polypropylene pipes (PP-R) are random copolymers of polypropylene, also known as type III polypropylene; they are copolymers in which propylene and other comonomer segments are distributed randomly along the main chain. PP-R raw material is a polyolefin; its molecules consist only of carbon and hydrogen, making it non-toxic with reliable hygiene properties. PP-R does not have any adverse effects on human health or the environment throughout the entire process of raw material production, product processing, use, and disposal; it is considered a green building material, on par with cross-linked polyethylene pipes. In addition to the advantages of ordinary plastic pipes, PP-R pipes also have the following features: They are non-toxic and hygienic, meeting **hygiene standards. They are heat-resistant and insulating – the Vicat softening point of PP-R pipes is 131.3 °C, with a maximum operating temperature of 95 °C and a long-term operating temperature of 70 °C; their thermal conductivity is 0.121 W/m·K. The excellent elasticity of PP-R material allows the pipes and fittings to expand along with liquids that may cause freezing expansion, thus preventing them from being damaged by such expansion. They also have good environmental properties. However, their resistance to ultraviolet rays is poor – they tend to age under prolonged direct exposure to sunlight. It is mainly used for transporting cold and hot water in buildings, in heating systems, as well as for water supply pipelines in facilities located by the sea. We used PVC in the past, but now we use PP-R, which works very well in terms of installation and use. PP stands for polypropylene, and it possesses excellent chemical stability, remaining inert to most acids, bases, salts, and oxidizing agents. For example, it is stable in concentrated phosphoric acid, hydrochloric acid, 40% sulfuric acid, and their salt solutions at 100°C; only a few strong oxidizing agents such as fuming sulfuric acid can cause it to change. PP is a non-polar compound and is very stable in polar solvents such as alcohols and phenols
I think it is possible to consider using PVC pipes for most of the overall piping system, with steel-lined PE at the inlet of the mixer. This way, the mixer has better strength in case of an explosion, and costs can also be saved.