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  1. pmureiko

    Ammonium Sulfate Corrosion Problem

    The bottoms stream from a hydrocarbon solvent distillation columns contains 5% water and dissolved ammonium sulfate salts. We are experiencing corrosion of our carbon steel piping near the column where the stream is hot (230 oF), but the piping in the tank farm where the stream has cooled off...
  2. pmureiko

    Thermosyphon Reboiler Outlet Line

    I'd look at how much the flow in each return leg changes versus differences in length, elbows, etc. If it is relatively small, then the "symetric pipes" have plenty of capacity to handle process and design variations. Is the thermosyphon reboiler being considered a stage for mass transfer? If...
  3. pmureiko

    Steam Allocation Problem

    If the meters are accurate, then the allocation of steam to user C by difference will be accurate. All users are paying for heat used through steam metering. I see the issue as who pays for the reduced boiler efficiency to produce high pressure steam when for one user (A), when other users (B...
  4. pmureiko

    Materials compatible with Hydrazine Hydrate and KOH.

    I remember hydrazine hydrate vendor literature lists 304L and 316L stainless steels as recommended materials of contruction. This recommendation for may be for ambient and not cover the high temperatures of your process.
  5. pmureiko

    History of HYDRAZINE HYDRATE explosions.

    The top cautions for using hydrazine hydrate were using proper materials of construction and good industrial hygiene. The suppliers recommend using stainless steel since the hydrazine removes the carbon steel oxide coating by reducing it to iron. This reaction releases heat and can cause a...
  6. pmureiko

    Six Sigma Certification, How marketable?

    I recommend getting the 6s training. It is being used as an applicant screening tool and has nothing to do with hiring a good, capable engineer. Get it so your resume will make it to the next review level. 6s is a useful tool, but management abuses it thinking it is a cure all that gets more...
  7. pmureiko

    Pressure control with flooded condensers

    Once the condenser if drained, it won't matter what happens in the accumulator. Draining the accumulator increases deadband and slows response if the tower pressure drops. Draining the drum can be used to drop pressure by venting vapor and non-condensables to a fuel gas / vent system.
  8. pmureiko

    air compressor dryer newbie question

    Barry is correct about the differences in refrigerated and dessicant air dryers. Another is the dew point of the air. I don't know if there is a cost in operation since the refrigeration system uses a compressor. A refrigerated dryer is limited to a dew point above 32 oF because it will stop...
  9. pmureiko

    compressed air adsorption dryers

    I recommend paying a little more for a heated air dryer to get much higher process reliablity versus the heatless air dryer. The dryer regeneration process is direct since water desorption is forced due to the heat input. Because of this, proper regeneration is easily checked and restored...
  10. pmureiko

    Vacuum Tower Pressure

    Using diesel as the eductor motive fluid was probably done for environmental purposes instead of performance, though there may also be a performance improvement. Previously steam was used for the eductors and was condensed with direct water contact to produce the tower vacuum. Unfortunately...
  11. pmureiko

    Desalter Operations

    An immersed radar gauge may be a reliable method to detect the interface level.
  12. pmureiko

    Hydrogen vents - Purge with N2

    The purpose of nitrogen dilution in your case is to bring the H2 conc. below the LEL. You would be going from 100% H2 to say 5% (I didn't look it up, but it is low). That means you will need 19 volumes of nitrogen for every volume of hydrogen, which works out to a ridculously high flow of...
  13. pmureiko

    96% H2SO4 Tank storage - Nitrogen purge or Dried Air - vent dryer ?

    Does this project have an attractive payout? This needs to be checked before any engineering resources are applied. Management comes up with all kind of ideas which then becomes your job to challenge and justify. Don't assume they know what they are doing. Because they have few cost control...
  14. pmureiko

    Pipe Freeze Analysis

    mechtimeng, Is the open & line flowing or blocked in? I'm guessing you calculated the time to completely freeze a blocked in line. It make take 17 hours to freeze a line, but this is different than the pressure profile. The formation of a small amount of ice in a blocked, liquid full line...
  15. pmureiko

    Enthalpy value calculation

    Gorkus, Please work with a local chemical or pump engineer to calculate what you need. You seem confused on the concepts of enthalpy, NPSH, and composition. At this rate I'm worried you will improperly apply these formulas and unknowingly proceed with the wrong value in purchasing equipment...
  16. pmureiko

    Injection quill material of construction, HCl application

    Check with a mechanical engineer on what size and thickness quill will be strong enough to resist the vibration forces. A larger diameter quill will be stiffer than one sized just to handle the flow. There is room to work with here since the line is large and the material costs from using a...
  17. pmureiko

    Constantly Relieving RVs, Who Cares??

    Is the relief valve (RV) constantly or frequently relieving? A lot of expensive product is being lost if the RV is constantly venting. If the valve does not reseat, then you will have constant leakage operators may not be aware of. The unit may be operating at a net loss. The cost of product...
  18. pmureiko

    Help!!! Insurance being cut!!!

    A lot of good responses to your question have been posted. Here are some thoughts I have others can build on or correct. 1) Letting the insurance lapse may be a sign they don't expect to stay in business much longer. As such the owners don't care whether someone sues the bankrupt or closed...
  19. pmureiko

    Reboiler Steam Flow Control

    This is a situation of expecting many things to be done without enough measured or manipulated variables. You are correct that there is no mechanism to prevent steam from blowing through to the condensate line. I suggest an external liquid leg with steam trap be placed on the condensate outlet...
  20. pmureiko

    acid under tank?

    I am worried that concentrated acid has collected under the tank bottom and is eating away at the bottom. Carbon steel is compatible with highly concentrated acid. Unfortunately the acid will be diluted with water from rain and humidity over time and aggresively attack the steel. You have...

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