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  1. BlackSmoke

    Sanitary Clamps in Flammable Liquid Service

    Re: EdStainless yes I am familiar with the requirements of the BPE standard. It implicitly mentions use in flammable service by stating that flammable materials should be protected with relief devices per the relevant codes (e.g. NFPA 30). I'm definitely interested in the details of a sanitary...
  2. BlackSmoke

    Sanitary Clamps in Flammable Liquid Service

    Thank you all for your responses, they were helpful to understand how others were practicing. In particular, moltenmetal's comment regarding firesafe certification triggered us to look at the codes again. I concur that I have not been able to find fire-safe gaskets for the sanitary clamps. I...
  3. BlackSmoke

    Sanitary Clamps in Flammable Liquid Service

    All, I am working on a biochemical process service where both flammable solvents and a sticky substance requiring frequent cleaning are used together. Sanitary clamps (<2" diameter) are desired to facilitate disassembly and cleaning, and I have been asked to confirm that they can be used in...
  4. BlackSmoke

    Time to heat a packed bed

    Sounds like a fun one, though not an easy one. Conduction will certainly be a significant factor, but it will be limited by the contact between particules - do you have an idea of the void fraction of the material? Essentially, there is an additional resistance to heat transfer that is a...
  5. BlackSmoke

    Determing a set point for a Liquid Pressure Relief Valve

    This seems like an odd (interesting) result. Double check all your meter calibrations of course. Based on my reading it looks like the elevation change was only 8' i.e. only 7 psi at SG 2. Also, if the pipe wasn't already filled with liquid, the valve should open at 140 psig. This means the...
  6. BlackSmoke

    Emergency relief: flare vs. atmospheric release

    I've gotten a new job in the wastewater industry and I've found that another engineer has specified relief valves that relieve sour methane gas to the atmosphere. The relief load is relatively small but the valve does not have a stack or anything to discharge it at a safe location, just a...
  7. BlackSmoke

    Restriction orifice upstream of control valve

    Of course, it depends on your fluid and the selected valve. You'd want to consider if your fluid is near saturation. If your restriction takes too much pressure drop, by the time the fluid reaches the control valve you might cause cavitation at the valve's restriction, leading to...
  8. BlackSmoke

    &quot;Map&quot; of Industrially Practiced Chemical Processes?

    I have seen examples flashed before me of comprehensive maps of the major chemical processes. This means showing how the 20 or so major raw materials are converted in the diverse portfolio of consumer chemicals. I have searched on the internet high and low, but I am having trouble finding...
  9. BlackSmoke

    PSV's and Applicability of 2010 ASME Sec VIII Div 1 to Heat Exchangers

    I took another read through the introduction. One might argue that the filter housings I am interested in could be classified as "strainers" as part of the piping system, though if anyone has a differing experience I'd like to know. This probably comes down to local regs at site, and whether the...
  10. BlackSmoke

    PSV's and Applicability of 2010 ASME Sec VIII Div 1 to Heat Exchangers

    Reposting after I got no responses over at the chemical engineering section, looks like a way better match here. There's been a lot of debate among my colleagues and clients regarding the interpretation of the ASME code for pressure vessels and heat exchangers. Unfortunately, much of our...
  11. BlackSmoke

    Calculation of upward force on a bed limiter ?

    had a similar issue a while back where in an upflow gas-phase metal catalyst bed, the johnson screen was being damaged during startups. The initial velocity of the bed as the gas flow was turned on caused the bed to slam in the johnson screen roughly as a solid plug, causing the cantilevered...
  12. BlackSmoke

    Basis for level trips at 90%, why not 100%..(of working vol)

    I'm definitely not an expert on instrumentation, but my understanding was that 90% was used because using 100% as an interlock was risky because the measurement depends on the expected density of the solution for differential pressure meters. Thus if there is a difference between the actual...
  13. BlackSmoke

    PSV's and Applicability of 2010 ASME Sec VIII Div 1 to Heat Exchangers

    There's been a lot of debate among my colleagues and clients regarding the interpretation of the ASME code for pressure vessels and heat exchangers. Unfortunately, much of our experience base is dated, and we may not have kept up with the changing times. We are the technology licensors, so we...
  14. BlackSmoke

    First Impressions?

    Program is a nice AutoCAD clone and seems to be reasonably interoperable with AutoCAD for simple drawings. Things we've noted about DraftSight: -Breaks datalink tables -Breaks dynamic blocks -No sheet sets or publishing of multiple layouts -Lineweights print much thicker, though we can take a...
  15. BlackSmoke

    Lineweight Compatibility with AutoCAD Style Sheets (CTB files)

    Hi all, I'm trying to set up a mixed working environment with AutoCAD and Draftsight. Most things are working quite well for us. One of our issues is that the same style tables seem to behave very differently in AutoCAD vs. Draftsight. The draftsight lines often seem to be substantially...
  16. BlackSmoke

    Vortex Breaker

    I typically neglect vortex breakers as well, though as a process designer I leave a substantial safety factor between NPSH available and NPSH required. I'm hypothesizing that you could get an estimate by calculating entrance losses for the hydraulic diameter rather than the nozzle diameter...
  17. BlackSmoke

    Cooling water temperature for a Distillation unit

    With colder water temps, partial condensers are of course affected by additional condensation of light compounds, but these temperatures should be actively controlled already. Some condenser types (such as horizontal shellside) would not show much additional subcooling, due to the fact that...
  18. BlackSmoke

    Dilute Vapor-Vapor Mixing

    Vapor-vapor mixing is often taken for granted, with a flush nozzle or nozzle shroud often considered adequate for most applications. However, I am working on a problem where a vapor stream must be fed to a reactor very well mixed. Unfortunately, the reactants must be mixed for a minimum...
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