Should recirculating water heat exchangers be categorized?
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This post was last edited by forowhl on 2022-11-1 09:09. I recently came across a heat exchanger with a shell-side operating pressure of 0.5 Mpa, using circulating water at 50°C. The working pressure of the pipe train is 0.03 Mpa; it deals with explosive media at 80°C. The designer said that the circulating water is in a full-liquid state, so no classification is needed. Is this statement being used? --------------------------------------------------------------------------------------------------- After reading everyone’s replies, I realize I might not have expressed myself clearly. Obviously, there’s no need to categorize the fully flooded state; I understand that. But who can guarantee that it is at full liquid level? “The circulating water contains gases, which accumulate in the dead zones of the shell side – this definitely happens; but who can guarantee how much volume can accumulate there?
Heat exchangers under such conditions do not fall within the category of special equipment
Media that are entirely liquids with boiling points below the standard value do not fall under special equipment
The circulating water in the shell side is in liquid state; the operating temperature of 50°C is below the boiling point. The operating pressure in the tube side is 0.03 MPa, which is less than 0.1 MPa. According to TSG21, it is not considered a pressure vessel
In a flooded condition, there’s definitely no need for classification. But how can we ensure that the shell-side circulating water remains in a flooded state? What if gas gets mixed into the circulating water?
This post was last edited by wanlirn on 2022-11-2 at 15:00. How can you be so confused? There might be dead corners where gas can accumulate; in that case, just make an opening there and add an exhaust vent – that’s all. For your current operating conditions, no inspection is necessary at all. If it’s designed for inlet at the bottom and outlet at the top, it’s impossible for air to get trapped
I’ve never seen anyone so stubborn; adding an exhaust pipe would solve the problem
I’ve never seen anyone so stubborn; adding an exhaust pipe would solve the problem
It seems like this guy isn’t in the design field; the pressure vessels have been classified incorrectly. Who will take responsibility if something goes wrong? Is full-liquid operation determined by the process specifications? Can anyone give you a written guarantee that it’s in a full-liquid state? Can you just say verbally that it’s full of liquid?
You can mark it and see if the boiler inspection agency will inspect it for you. If there’s even a slight element of responsibility involved, they won’t conduct the inspection for you. You can try reaching out to the boiler inspection agency