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  1. ghopkins

    Lining for Sodium Hypochlorite Tank

    Graybeard: One last comment: In your risk analysis between the two types of construction, some factor should be applied for catastrophic failure. I'm assuming if the rubber lining fails, the steel structure will not last very long and provide the potential for catastrophic failure, perhaps in...
  2. ghopkins

    Lining for Sodium Hypochlorite Tank

    Graybeard: I myself haven't heard of rubber lined carbon steel being used in NaOCl service. The eight years service life is quite respectable. All you can expect from straight fiberglass is about 7-10 years if its built properly, as I mentioned above. The cost for this type of construction...
  3. ghopkins

    Emptying of Concentrated nitric acid tank(98% HNO3)

    Panteo, The tanks are large, but could a vacuum condition ever exist? Vacuum rated flat bottoms can be expensive in such large tanks. For example, if the PVRV is rated for -8" WC, then maybe the drain was located 8" (or equivalent given SG of HNO3) above bottom so it won't...
  4. ghopkins

    reinforced fiberglass plastic

    Also try www.creativepultrusions.com
  5. ghopkins

    H2O2 resistance

    What kind of equipment are you looking for? The kind of equipment required could help in determing the right materials of construction. i.e. are elastomeric seals required? Is the equipment even rotating or is it static, like a storage tank, etc. Is it short term exposure or long term? Also...
  6. ghopkins

    Using Carpenter 20 in H2SO4

    The Carpenter 20 would be used in a 6000 gallon storage tank. 96-98% H2SO4 is received by truck. Because the tank is vented to atmosphere, the moisture pickup drops the concentration to approximately 93% (+/- a few %) before the next load. A nitrogen pad to keep the moisture out is probably a...
  7. ghopkins

    Experience with Epoxy coating for interior of large diameter tanks

    Has 100% FRP construction been considered? There are a few companies that can build FRP tanks as large as you require. Resistance to organics is of primary concern, but a novalac epoxy vinyl ester resin (i.e. DEREKANE 470) should suffice. For manufacturers to build this type of equipment, see...
  8. ghopkins

    Using Carpenter 20 in H2SO4

    Are there any drawbacks to using Carpenter 20 in 93-98% sulfuric acid service? Is Carpenter 20 the same as Alloy 20? The temperature is ambient (-30 to 110F). Thanks
  9. ghopkins

    Looking for carbon graphite tube

    I have experience with both companies and both are very good. Try: Creative Pultrusions Inc. 214 Industrial Ln. PO Box 6 Alum Bank, PA 15521 USA Tel: (814) 839-4186 Fax: (814) 839-4276 Business: Pultruded tubes and structures OR: DFI Pultruded Composites Inc. 1600 Dolwick Dr. Erlanger...
  10. ghopkins

    Inspection of FRP tanks in service

    I recommend getting a copy of the latest ASME RTP-1 standard, which will answer all of your questions about fiberglass construction for vessels rated from full vacuum up to 15 psig. http://members.asme.org/catalog/CategoryView.cfm?Category=CS&Designator=RTP A lot of chemical companies (such as...
  11. ghopkins

    Resin Infusion Info (the basics) wanted

    Hangglide, My company has been doing infusion for several years now using the SCRIMP process. We have found this process very effective for certain applications, however, we've begun recently to use the CARTM process. With the CARTM process, we've infused panels as thick as 4" and...
  12. ghopkins

    Boiling weak sulphuric

    Flouropolymer (Kynar, Halar, or Teflon) lined fiberglass (dual-laminate) can be used for the column, feed tank, and product tanks and would be more economical than Hastelloy. In addition, PTFE internals can be manufactured to hold up to the constituents. Heat transfer becomes a bit of a...
  13. ghopkins

    Need Recommendation for vessel holding 28% Sulfuric Acid

    DougW: more information to digest: Please see following links for corrosion recommendations of vinyl ester resins used in fiberglass constructions: Accessed through (www.hetron.com): http://www.ashchem.com/ascc/compoly/cg.asp?nCountNumber=281&alpha=S&is_header=N I would recommend Hetron 922...
  14. ghopkins

    Need Recommendation for vessel holding 28% Sulfuric Acid

    I would go with the fiberglass option using a Section X, Class 2 code stamp (if you're in one of the 28 states that requires a Section X stamp on pressure vessels). Even if you're not in one of the states that requires it, I would still go with a code stamp if the vessel was in my plant... The...
  15. ghopkins

    failure of pump in phosphoric acid plant

    I'm not sure about metallics, but we're helping out a phos acid plant right now who uses lots of Teflon-FEP lined fiberglass pipes and tanks. This material seems to be working out exceptionally well for them. Perhaps the wetted surfaces of your pump can be coated with Teflon FEP or PFA. Greg...
  16. ghopkins

    Frp for chloralkali plant?

    Definately use vinyl ester resins. Dow Chemical and Bayer (just to name a few) have been using fiberglass made with these resins for over 30 years - specifically in their chlor-alkali processes. I will echo the comments about using an RPT-1 fabricator. Dow Chemical and Bayer primarily only...
  17. ghopkins

    Sulfonic acid handling

    In terms of non-metallics, my corrosion guide states the following regarding flouropolymers: PVDF (Kynar) - prone to stress cracking even at 25 C. ECTFE (Halar) - excellent to 50 C. FEP (Teflon) - excellent to at least 150 C. PFA (Teflon) - excellent to at least 150 C. I should point at that...
  18. ghopkins

    Lining for Sodium Hypochlorite Tank

    Here are some links for more information: http://www.odysseymanufacturing.com/bleach_information.doc http://www.solvaychemicals.com/docroot/chlo_inorg/static_files/attachments/hypo_general_brochure.pdf (takes awhile to load) And perhaps the best resource (but you have to buy their manual) is...
  19. ghopkins

    PVC Lined GRP tanks

    rsauk, I apologize, but I need to make a correction. The 6% knuckle radius requirement is only for joining dished heads to a shell. For flat bottoms, part 3A-120(d) of the ASME RTP-1 code calls out a minimum radius of 1&quot; for vessels <=4' in diameter and 1.5&quot; for vessels >4' in...
  20. ghopkins

    PVC Lined GRP tanks

    The applicable code in this case is ASME RTP-1, which makes special provisions for thermoplastic linings of GRP - called dual-laminates as suzuki mentioned already. The ASME RTP-1 code does NOT allow square edge joints between the shell and end closure. It specifically states that a 6% knuckle...

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