Is this configuration violate any codes (US & Canada)?

[rutherford703]

The attached drawing is a naphtha heater. Naphtha can be blocked in while the steam keeps flowing. A thermal relief valve is provided for such a scenario. The PSV directly discharges to the OWS (Oil Water Sewer). We realized that it is not a good design; however, it is a grandfather plant. Does this configuration violate any codes (NFPA) (US & Canada)?

Thanks in advance.

 

[rutherford703]

sorry the attachment does work

Thanks

 

[moltenmetal]

What's your concern: the destination of the relief tailpipe, or the relief design?

Thermal expansion relief isn't going to discharge much material- a tiny burp will relieve the pressure. But what happens if something keeps the PSV from resealing? Or are there any other cases that may cause the relief valve to discharge?

 

[SNORGY]

On first inspection, 1" x 2" is a big "thermal" relief valve. Is that the size of valve you really need, and is it "thermal" or is it "vaporization due to heat input"? (Naphtha BP = 160-220 C?) Completely different situations in my mind. I would be looking at how big everything is and how much actual volume could be passed to OWS, what phase is the naphtha when it gets into the OWS, and what happens to the Oily Water after it gets to the Sewer. I'd be looking into a little knockout or pop tank or something.

 

[moltenmetal]

You should at least have controls on the steam. That's just commonsense.

Snorgy's right that a 1x2" relief valve is probably capable of leaking the thermal expansion relief case when fully closed. What case was it really sized for?

 

[rutherford703]

Thanks for all your valuable information!