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  • Users: jalvarez
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  1. jalvarez

    Normalized A-105 or 316L?

    We are doing a modification in a line carrying anhidrous Hydrogen Chloride. The original materials are ASTM A-333 Gr 6 for piping and A-350 LF2 or A-420 WPL6 for accesories. We are installing a low point in a Ø 6" line, and we need to install now a 6" blind flange there. Operating conditions...
  2. jalvarez

    Branch connections practices

    ASME B31.3, paragraph 304.3.2 establish "that a branch connection has adequate strength to sustain the internal and external pressure which will be applied to it if:" And among the "ifs" the point (b) mentions that the size of the branch must not exceed one-fourth the nominal size of the run...
  3. jalvarez

    ASME B.31.3 doubt

    Hi, mates: In the paragraph M341.4 (b)(1) it appears: "The random radiography/ultrasonic examination requirement of para. 341.4.1(b)(1) apply except that at least 20% of circumferential butt and miter welds and of fabricated lap and branch connection welds comparable to those shown in Figs...
  4. jalvarez

    Passwords... and MS bugs...

    Protecting an Excel spreadsheet for writing and selection of some cells, I defined a password. One month later... I forgot the password. Doing a search for lost paswords, it was found SPPBABF as the lost one. Immediatly, I could remembered the first one, SPPFORM. Surprise, the two words works...
  5. jalvarez

    Assuring sealing with bellows for critical control valves

    Hi mates: Your opinion or experience: For a control valve in a vapor anhidrous hydrogen chloride service, (minus 32°F - 170 psig), is it reasonable to use a metal bellow for sealing the stem to the atmosphere, additional to the conventional sealing system? I think that the efectiveness of a...
  6. jalvarez

    Log plots & maximum for "y"

    Refining Excel results... [pipe] Hi, colleagues Sometimes, making a plot in Excel, we may prefer a logarithmic graphic. This is an option using the Excel wizard for a graphic. But trying to define the maximum value for the "y" variable, Excel increases such muber to the log decade immediatly up...
  7. jalvarez

    Pumps inside a diking area for a low flash point HC

    Hi mates Is there any specific reference (API, NFPA, etc.) defining or recommending about the location of a pump outside of the diking area of a tank, considering that the tank handle a low flash point hydrocarbon? The only reference I've found is an old "recommended practice" that accept the...
  8. jalvarez

    CS pipe for a H2O saturated gas stream, 20 ppm chlorine?

    Colleagues The tittle summarize the question. Is it reasonable to use Carbon Steel in a pipe for a gaseous stream, saturated with water, containing 20 ppm of chlorine? Other gases that are present are inert from the point of view of corrosion, like nitrogen, methane, etc. How many mpy's of...
  9. jalvarez

    HAZOP and/or MOC, legal requirement

    Hi mates: I've possed the folowing question in the OSHA Code Issues forum, but I'm repeating it here as maybe a more wide expertise is connected here. I like to know if there exists in the USA, Europe or other countries a legal requirement that imposes a register of modifications, HAZOP's, MOC...
  10. jalvarez

    HAZOP and MOC, legal requirement

    Colleagues: I like to know if there exists in the USA, Europe or other countries a legal requirement that imposes a register of modifications, HAZOP's, MOC system, etc., for the Chemical, Petroleum, or Petrochemical Industry. (I'm assuming that this must exist already in the nuclear industry)...
  11. jalvarez

    SS's - potassium iodide

    Hi, mates: The limitations of SS's in aqueous chloride solutions is very known. Many threads have been written on this issue, some of them recently. But, what are the differences with other halides solutions? The chemistry of all halides should be similar, but... I've a case with a vessel...
  12. jalvarez

    CS vs SS corrosion mechanisms

    Colleagues: I need to define the material for a pump; the fluid is a brackish solution, NaCl content of 1%. Some other salts like sulfates. The pH is neutral. The temperature is 95°F. Looking at a corrosion design curve for brackish waters, I verified that for Carbon Steel, a straight line is...
  13. jalvarez

    Corrosion of SS316; Chlorides & Sulphides

    Hi mates: I did a search and want to revisit your thread338-52646. There it was clear that, if correctly passivated, SS316 or still 304 is/are correct for piping with water with a chloride content of 200 ppm, occasionally more (as high as sea water), provided that: - The lines are correctly...
  14. jalvarez

    Fouling in chlor-alkali plants

    Hi, mates: Have anyone any experience about chlorobenzenes fouling in chlor-alkali plants? This used to be a problem when using graphite anodes, especially with hexachlorobenzene, but it seems not to be a common issue nowadays. But we are not using graphite anodes here and have some of these...
  15. jalvarez

    Thermal expansion protection

    Just to present a case, maybe this is an extension of the one titled “Thermal Relief Protection for Short Sections of Pipe”: A pipeline, approximately 10000 ft long, between a tank and a port, was provided with several block valves, targeting to limit the consequences of a possible release. As...
  16. jalvarez

    Hydrogen vents - Purge with N2

    May anyone in the network recommend me a criteria to define the flow of N2 to effectively (and economically) purge a hydrogen vent? Obviously, I'm trying to minimize the probability of an explosion/detonation, due to lightning or occassional sparks. I'm speaking of a couple of vents, 16 and a...

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