More info needed. At temperatures below 100F they are comparable but B2 will cost more. Corrosion will also be highly dependent on what else is in your brew.
This is for application above the water spray in an HCl scrubber. Temperature will be below 100F. There may be trace solvents (PPM) in the HCl gas stream, but don't know the exact composition of any HCl that may be entrained in the scrubbing water mist.
If there is water failure the vapor temperature entering below the packed bed is 80F, concentration is ~100% HCl, with the possible trace solvents mentioned above.
Dry HCl isn't a problem at 80 F. B2 is much more resistant to conc HCl than C grades are, but personally I think B is overkill for this.
If the purpose of the scrubbing is to remove HCl, that's one thing. If the purpose is to MAKE concentrated HCl, then you'd need B or even refractory materials.
B is vulnerable to even traces of oxidizing species in the mix. Fe+3 is particularly bad. But C grades are pretty resistant at low temperature. I posted a link to a NiDI paper on the subject recently in a similar thread- have a look.
