90°C 32% caustic soda solution mass flow meter
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Seeking help from expert seniors! At 90°C and with a 32% caustic soda solution, a mass flow meter should be used at the P-274A/B outlets to measure density. What material should be used for the flow meter’s measurement tube?
Two conditions are required for the occurrence of alkaline embrittlement; carbon steel, low-alloy steel, and austenitic stainless steels can suffer from alkaline embrittlement. It is best to choose high-nickel cast iron and nickel alloy materials.
Just choose a mass flow meter made of Hastelloy; several major manufacturers of mass flow meters offer models made from this material. Or nickel materials can be used directly, but special customization is required.
Both are made of HC-22 material; however, the temperature resistance of the material specified by E+H does not reach 90°C, while Emerson’s version can handle such temperatures, which is a source of concern for me
This result is a qualitative one, but it is based on the degree of acceptance of different corrosion data. It is best to explain it using the annual corrosion rate. If in doubt, choose nickel material directly.
When the weight percent concentration is below 50% and the temperature is 200 °F (93 °C) or lower, stainless steel sensors exposed to a \"pure\" sodium hydroxide solution do not develop stress corrosion cracks or corrosion fatigue. However, higher concentrations, especially at higher temperatures, can lead to failures. Under these conditions, nickel alloy C22 is recommended. Nickel alloys (such as nickel alloy C22) are resistant to sodium hydroxide at all concentration ranges, even in solutions at boiling point. The presence of chloride ions is highly detrimental to the lifespan of 316L sensors. If the presence of chlorine is possible, nickel alloy C22 should be used.
Hehe, expert-level predecessors aren’t necessarily useful; what matters is having the relevant materials and experiments. The Emerson mass flow meter instructions state that when the weight percentage concentration is below 50% and the temperature is 200 °F (93 °C) or lower, the stainless steel sensor exposed to a \"pure\" sodium hydroxide solution will not develop stress corrosion cracks or fatigue corrosion. However, higher concentrations, especially at higher temperatures, can lead to failures. Under these conditions, Hastelloy C-22 is recommended. Nickel alloys (such as Hastelloy C-22) are resistant to sodium hydroxide at all concentration ranges, even in solutions at boiling point. The presence of chloride ions is highly detrimental to the lifespan of 316L sensors. If the presence of chlorine is possible, Hastelloy C-22 should be used. I checked Emerson’s official manual; within the range of 86–120°C and a concentration of 0–100%, only one type of tubing meets the requirements, namely 316L material lined with polytetrafluoroethylene. In other words, within the temperature range you mentioned, concentration no longer plays a significant role; only this material can be used. Furthermore, what agents or salespeople say is not necessarily reliable; it’s better to trust the data. If you want to learn more, you can look at foreign literature; domestic ones won’t do.