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  1. misterd

    Packed-bed scrubber - Acid washing

    We are operating a packed-bed scrubber for odour removal (SO2). A caustic/hypo solution is used to scrub mercaptants. Would anyone have a recipe for acid washing to remove scaling? I have read about muriatic, sulphuric and phosphoric solutions but I cannot find the recommanded...
  2. misterd

    Estimating software

    We are looking for an estimating software for our company. We have identified a few potential ones, but the webpages are pretty similar. Has anyone heard of Skire? International Project Estimating? These softwares are combining many options (and softwares) and are more powerful than MS...
  3. misterd

    Stacks?

    We have to install a 16' high exhaust stack made of SS 316. The temperature of the gases passing through the stack will be around 780 F. Questions : - At what height should we attach the cable? - Is there a recommanded angle for it? - What should we install to consider high temperature...
  4. misterd

    Outside Ducts: Issues?

    Snow and ice load? Wind load? Maintenance load? The choice of material might vary depending on your environment. Also, don't forget special support or hanger etc. These factors are well documented in "Round industrial duct construction standards", published by the SMACNA. After reading...
  5. misterd

    Innovative Septage Treatments

    Russiangoat, We are actually working with a local promoter to develop an innovative composting system. Pilot units are installed in Ontario and Quebec (Canada) and the results are interesting. For more information, contact me at my professional address and I will put you in contact with the...
  6. misterd

    pH system - Design criteria

    This tank would be used to adjust pH before discharge. Once the pH is below discharge limit, we can dump it. No need for a highly precise tuning. The pH should not vary too much, but it is not possible to estimate precisely the range (too many variables for now). I am just looking for a rule...
  7. misterd

    pH system - Design criteria

    What is the design criteria for sizing a tank that would be used for pH adjustment? Assuming continuous feed of 25 gpm, proper mixing, what would be the proper dimensions for the mixing tank?
  8. misterd

    Ventilation ducts - Wall thickness?

    Where can I find standards in order to determine the right gage for a new ventilation system (6500 CFM, 320 F, low pressure)... Thanks
  9. misterd

    Quench tower?

    We have to design a quench tower to cool down hot air (420 F) to 140 F. The quench medium would be water. What diameter for the quench? length? residence time? Do we nedd packing?... Thanks
  10. misterd

    SAND SPECIFICATIONS

    What about the uniformity coefficient (Cu)? It would indicate on average how uniform is your sand-. Have you tried with anthracite or another medium? What about the filtration rate? Are you sure that physical-chemical treatment is efficient?...
  11. misterd

    Estimated Wastewater Flows

    Restaurant with drive-in (typical fast-food) : 60 L/day per parking or seats. Otherwise, 50-75 L/d per employee. These are the design criteria accepted by our local authorities. Hope it helps.
  12. misterd

    Oily Seawater separator - Material?

    Thanks for the reply. If those metals are unavailable, what about SS 2205 or hastalloy? My charts are really vague ont the subject...
  13. misterd

    Oily Seawater separator - Material?

    We need to build a wastewater unit for separating oily water genereted by a naval test establishment. Water is heavily contaminated with solids, cleaning chemicals, emulsied oil and synthetic seawater. From the collection tank, the wastewater will be treated through an ultrafiltration unit...
  14. misterd

    air removal

    We have protecting our units with air vents sold by Armstrong international inc. It is really cheap and reliable : just check for pressure ratings and chemical compatibility. I would also recommend to install the air vent at the highest point. Good luck.
  15. misterd

    Vibration criteria for piping

    I have found some interesting information (formulas, examples...) in this document. This is a general document about liquid process piping. http://www.usace.army.mil/inet/usace-docs/eng-manuals/em1110-1-4008/toc.htm
  16. misterd

    Induced air? Cavitation? Pumping problem

    All seals have been checked earlier and we don't have any leaks or pressure lost. While investigating on the pump, we realized that we had microbubbles when we were choking a valve. At first, we tought about the pump because that valve has a direct effect on it. When the valve is completely...
  17. misterd

    Induced air? Cavitation? Pumping problem

    We installed an air vent on top of the recirculation loop (highest point) and on top of our filter bags. We suspect, that small bubbles are not captured by the vents. Eventually, those small bubbles become big bubbles! From what I can understand, bubbles of air passing trough the membranes...
  18. misterd

    Induced air? Cavitation? Pumping problem

    We took special care in order to avoid vortexing and triple checked our connections...hummm. The pump inlet is 2". Half of the inlet piping is 2" and the other half is 1½" (don't ask why...). Is it possible that the increase in velocity in the 1½" piping creates a depression lower than vapor...
  19. misterd

    Induced air? Cavitation? Pumping problem

    We are starting a new wastewater unit using ceramic membranes. The problem with those membranes is that they are "allergic" to air. If the water stream contains air, the membranes will collapse. After running for a month, one membrane exploded...After analyzing the possible causes, we are...
  20. misterd

    PVC/FRP Tanks - Thickness?

    You are right - but suppose you receive two different sizing coming from two manufacturers. Undersized or oversized?
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