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Latexman, Thank you for your suggestion. Interestingly enough I did it the way you suggested, as well as breaking it up into nodes, and both results only differ by about 4% (though I could iterate further and get it a little closer). Thanks for your help!

What I am attempting to do now, in leiu of simulation software, is break up the piping in nodes with K < 100, changing the specific volume accordingly...

E.g. Largest diameter of pipe in system is 3.94 ID. One section of pipe in the system is 330 ft of 2.067 ID pipe. Beta = 2.067/3.94= 0.525 If Moody friction factor = 0.020, then: K= 12*0.020*330/(2.067*0.525^4) = 497 Just this section alone has K greater than 100. Adding up the other...

Hello All, My brain's a little fuzzy this afternoon, but I'm running into a problem with Crane T.P. No. 410, pg. A-22 "Net Expansion factor Y for Compressible Flow..." For my example: P1 = 40 psig + 14.7 = 54.7 psia P2 = 0.397 psig + 14.7 = 15.097 psia DP = 39.603 psia DP/P1 = 0.724 K = 752...

We are going to use a 1500 gal. tank as a mineral oil hold tank; totes of mineral oil will be pumped into the tank and mineral oil will be metered from the tank for various uses. The only "process" in the tank will be to heat it to 100C while sparging N2 to drive off enough entrained water to...

Hi All, We have a knockoutpot which takes in multiple reactor vapor vents (typically set to 1 psig or a few oz's) from a different building. Each vent line typically connects vents from multiple reactor sources. Great pains have been taken to ensure that for each vent line to the...

I agree. I did find this which is very helpful: http://www.cheresources.com/steam_tracing.shtml

There is an existing relief valve (1/2" x 3/4") on an 8" NPS #6 Fuel Oil header. The header is traced with 75# steam. The header is ~545 ft long. I am sizing the relief valve for thermal expansion and getting 273 GPM required flow, per API 521-2007, pg. 33, which in my experience is WAY more...

Can you have a Section IV relief valve on a Section VIII rated vessel? The vessel (water-water "water heater") is is rated: shell = 155 psig @ 220F, Tubes = 150 @ 315F. The operating temps. are shell= 160-180F, tubes = 40-140F. Operating pressures well within MAWPs. The relief valve is a...

Ah ha. I thought it might. I wanted to confirm prior to purchasing the latest edition. Thanks again!

I noticed that between the 6th and 7th editions of API 520, part 1, that External Fire sizing on process vessels has been omitted. Specifically, the 6th edition includes 'Appendix D-Determination of Fire-Relief Requirements' wherein the heat load due to fire on the wetted vessel surfaces can be...

Ahhhh, good point. Analogous to evaporation rates, I assume. Thanks for the help.

Stab in the dark: A client has a 3-way safety selector valve with (2) relief valves, circa 1960s, on a 75 psig steam line. They want to replace the 3-way and eventually the relief valves (down the road). The failure scenario is a failure of the 300 psig/75 psig pressure reducing station OR...

I have a relief valve on a reactor that we are considering a fire scenario, 85% filled with heptane. My concern is that the normal auto-ignition temperature of heptane is ~399F-433F and at the set pressure of 50 psig, the corresponding vapor temperature is 320F. I have read that a species'...

The relief valve discharge of a thermal expansion scenario, with two species, is expected to be one species will remain liquid, the other will partially flash to vapor with the rest remaining liquid. The relief is calculated to be relatively small (<3GPM liquid at the RV inlet) through a 1/2" x...

The existing valves are rated for liquid relief. I was going to size the pump relief valves for their maximum capacity (as a function of maximum operating viscosity) and the exchanger relief valves for vaporizing liquid due to external fire. I assume that if a flooded vessel relieved during a...

rbcoulter, 1.) The issue of the #6 fuel oil being in a PSM area isn't for the flammbility of the #6 oil, but for the other chemicals in the area. The concern would be for those other chemcials to cause an external fire and lead to the heating and subsiquent vaporization of the oil in the...

Thanks for the reference, I went ahead and ordered the book. I'm familiar with latent heat estimation using Watson's correlation, Clausius-Clapeyron Equation, and Chen's Rule but of course variables in those equations, e.g. critical properties and molecular weights, are typically difficult to...

The relief valves are on an oil pump and an oil heat exchanger (steam in the tube). The area the relief valve is in is a PSM (process safety management) area that is considered for external fire. Are hydrocarbon relieving valves exposed to fire sized the same way as the "vaporizing liquids"...

I have a heat exchanger that external fire is considered the controlling scenario for over-pressurization. Currently, relief is in the form of a 6" x 10" relief valve on the inlet to the shell ~1000 ft. away in another building. I know per ASME XIII that an ASME coded vessel requires at least...