Issues regarding the use of 304 and 316 in water-bath vaporizers
Thread Content
Hello everyone, I’m facing this problem right now: A customer’s water-bath vaporizer is made of 304 material. Due to excessive chloride ions in the circulating water, at around 40 ppm, and a temperature of 90°C – whereas the specified concentration for this equipment is 25 ppm – severe corrosion has occurred in the device. The customer now wants to change the material to 316, but I’m not sure if, apart from an improved corrosion resistance, there will be any effects on other properties ? As a supplement, liquid nitrogen flows in the tube side of the vaporizer at a temperature of -196°C, while circulating water flows in the shell side at a temperature of 90°C. Also, I would like to ask about the operating temperature range of 316; we usually use it in high-temperature environments, but I’m not sure what temperature range it can handle in low-temperature conditions ? I would be very grateful if an expert could help me solve this problem; I’m a beginner.
In carbon steel with a nickel content exceeding a certain level, the transition temperature for low-temperature embrittlement decreases significantly, while low-temperature impact toughness increases markedly; therefore, nickel-containing steels are often used as materials for low-temperature applications. Under normal conditions, nickel steel with a nickel content of 3.5% can be used at low temperatures of -100°C ； Nickel steel with 9% nickel content can be used at ultra-low temperatures of -196°C. Nickel-containing low-alloy steels also possess high resistance to corrosion fatigue. 316 stainless steel can withstand -165°C; 316L is recommended.