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Injection quill material of construction, HCl application 3

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ProjectEng

Chemical
Nov 6, 2002
55
Hello,

I am injecting approx 100gpd of 36% muriatic HCl into a 16" 316SS line. 3750gpm of water is flowing through the 16" pipe.

I am looking for an injection quill that can easily handle the HCl as well as vibration in the pipe. Plastic/PVC/teflon/etc are not desirable. I prefer an exotic alloy for strength and safety.

We are replacing a Hastelloy C-276 injection quill because the 9" stinger broke off and got lodged in the static mixer downstream. What is the best and strongest material to use in this application?

Thanks.
 
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you have to do a stress analysis and run checks on flow induced vibration before you sort out refinements to your materials.
 
The Kirk-Othermer Encyclopedia of Chemical Technology cites Hastalloy B and tantalum as best choices for all concentrations and temps. High chrome materials like 316SS and Hastalloy C's are not shown to be as good, especially above 125F.

With respect to vibration analysis for injection quills, I usually have one of our instrument engineers run a check using the program they use to check thermowells. They can advise you if a vibration problem looks likely.
 
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 short quill are low.
 
Project,

As stated above, stick with the C276....Its extremely corrosion resistant in many applictions.

You can get specific qualitative and comparative info from Alleghney Ludlum (and others)about C276 in HCl.... use the UNS number (N10276) when performing a websearch....always use GOOGLE

"When in doubt, make it stout".....use the thermowell vibration prediction methodology to evaluate the quill....it's the only one I have ever encountered.

Also consider the flexiblity of the mounting point on the piping system.....you may want to add gussets to the flanged insert (??!) where the quill is inserted. If the mounting point is too flexible, the stiffest quill in the world will still vibrate....

My opinion only......

MJC

 


A vendor told me this morning that B2/B3 Hastelloy is only good for reagent quality HCl. Our muriatic acid contains approx 5ppm Fe which makes the acid corrosive to Hastelloy according to this vendor.

C-276 is something we've tried before and has corroded in 2 months. According to the Compass Corrosion Guide, C-276 is only rated as 'C' for 36% HCl.

Tantalum will work I think but it is prohibitively expensive; one manufacturer wants ~10k to make a quill out of this exotic metal.

And supposedly DIABON Impervious Graphite will work but I have not seen the details yet.

I did not expect this application to be so difficult. I guess most people just use PVC.

Ideally, I could find a Hastelloy quill that's lined with Teflon but I have not found anyone capable of doing that yet.
 
PEngr: you need to be a bit more specific about your requirements. injection quills can be simple on paper but to make them work requires a lot of attention to detail.

MJC: thermowell evaluation codes are conceptually a good place to start, but none of them are really capable of handling this particualr application.

several problems. for example, none of the commercially available software packages are based on a self-consistent and verifiable engineering basis, additionally most trace their basis for design back to the asme performance test codes. believe the latter have been shown to be based on simplified notions about flow induced vibration that are justifiable in medium pressure steam but not liquids or high pressure compressible flows.

this particular quill is in a cross flow application with a liquid filled bore and as you mention probably with an imperfect boundary condition at the pipe wall. tough problem. it has been solved before (both as an engineering code an as a less general spreadsheet calc.), but try interesting people in using it. the problem: the results are basically a stress analysis and it requires engineering back ground and experience to properly interpret.



 
My experience with aq. HCl shows tantalum to be best material of choice. To keep costs low, Astro metals in Texas can both line and coat a carbon steel pipe with ~100 mil tantalum and weld at the ends. They used to make chlorine spargers for me for direct photochlorination reactors for toluene. Regarding the previous post for Diabon (carbon), this material is both soft (erosion) and brittle (think glass) so for vibration service I think it would be problematic.

Haynes has the new Hastelloy C-2000 which is supposed to have much better corrosion properties for HCl. It might be worth checking their website at
 

Well I got a Kynar quill with large wall thickness. I'm pleased with the stiffness, looks like it may be hardy enough for my application.

If not, I'll definitely look into tantalum-lining, dcguffey...I had no idea this was an option.

Thanks.
 
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