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The PSVs are supposed to never open as said by the posters above. The depressurisation valve normally operates at a pressure below the set point of the PSVs so that disturbances can be controlled away and the PSVs do not need to open. If a PSV actually opens, one would have the hassle of having...

So often I come across heat exchangers in which the process side has a high design pressure and the utility side has a design pressure of 10 bar (150 psig). The utility side is often thermal oil or heating water. The process side invariably have operating pressures and therefore design pressures...

Yes, that seems to be the most appropriate fix. 170 bends of which approximately 50% have too wide OD's (by 2mm). The construction contractor is probably going to make a casino out of this. Let us see whether he has the equipment to do it. Is this a normal event ("taper boring" or "tapper...

Fawkes, you seem to be immersed in all this PED-EN stuff. There are some concepts mentioned in your post of which I cannot make head or tail. I apologise for asking you here and not going through all the material presented in your link. I would get lost in there. What is a "harmonised"...

Thanks to both of you. I had the ISO 15590-1 sitting there on my computer, but it did not enter my mind to look for it. That is a problem if one is chasing standards in different systems. The ISO states a tolerance in the ballpark of the API 5L spec for line pipe (i.e. far stricter than the...

I think I understand now. Thanks.

Fawkes, what you have written corresponds to a large degree to what our notified body has told me a few days ago with respect to ASME Div 8 (pressure vessels). For pressure vessels in essence it would be easy. The pressure test needs to be adjusted as you have explained. For pressure vessels...

BigInch, thanks for your reply. In my present case the actual wall thickness exceeds the minimum required by API 5L by far. The problem is in the outside diameter at the bevel. The actual is larger than what the + tolerance of API 5L would have allowed (by 4 mm on 42"). But it is within the...

Which standards actually apply for the dimensional tolerances of the OD at the ends of induction bends to be used in an ASME B 31.8 42" pipeline? API 5L (43rd ed.) table 8 gives tolerances for the OD of pipe-ends, which are quite tight. I can see that these tolerances ar fine for straight pipe...

O481 Do you have a photo of that rig? I assume it is a 50t , but I cannot find any details of the Romanian T50B on the web. It is for my own interest.

There is a lot you can inspect! Is it an old rig, which has been in for service and has been repaired? --> API 4G. I found the CAODC (Canadian Association of Drilling Contractors) guidelines very useful for the structural elements of work-over rigs. The main emphasis on the rig structure will be...

340°F is the boiling point at 103 psig. What is the purpose here? To evaporate water and concentrate the slurry? Or to soak the solids at 340°F with little evaporation of the water? For pumping at the boiling point, you have to ensure that you have sufficient NPSHA. I.e. the level control in...

In some water-oil mixing processes a throttling valve is used to create a given pressure drop. The valve induces sufficient turbulence and shear forces to break up the water and oil phases into droplets small enough to allow intimate contact between the phases. I do not know whether this...

Bourbon, I cannot say whether the AIT comes down with increasing temperature (I thought it stays the same). But what interests me, is why AIT is a criterion in your case. I understand that the boiling temperature of heptane at 50 psig is 320F as you say. But as soon as the vapor exits from the...

The concept of dynamic pressure is nicely illustrated by the working principle of pitot tubes (air plane air speed) and anubars. The pitot tube is bent into the direction from which the fluid is flowing (or into which the air plane is flying). It measures the dynamic pressure plus the static...

My view is that other than causing fire and explosion within the LEL-HEL range, O2 can also be responsible for side reactions and corrosion in refinery equipment already at the ppm level under process conditions. That is one reason I would want to get the O2 level as far down as practically...

RJB, correct. The procedure is OK for run of the mill applications and is cheap. With the fixed orifice, the min. flow will always be pumped additionally to the required process flow. Can be energy inefficient in some applications. Also watch out for fixed orifices in high deltaP applications...

The pipeline pressure is 1170 psi. If that pressure is reduced to flare pressure there would be about 30 to 40°C temperature drop by the Joule-Thomson effect. Could this temperature cause the flare drum nozzle material to go below its brittle limit and therefore cause a failure? This seems to...

Thank you all for your input. I have not posed the question why SS piping feeds into the CS scrubber to the design staff yet. It could be that there was a supply limit (scrubber supplied by compressor manufacturer and rest of plant by EPC) and that somebody overlooked the dissimilar metal...

For pump sizing allow 200 mbar permanent pressure drop for an orifice flow meter. That is about 2-3psi as mentioned above. They actually come in at 60-120 mbar permanent pressure drop.