Sulfonic acid handling 1

[mythony]

For storage and handling PTSA or 'para-toluene sulfonic acid' we used to have piping and equipment in AISI 316.

Over the years, we gradually transferred to duplex SS material, because of several problems of attack of the 316 type (especially for the valves).

For instrumentation, we're thinking about switching to another, more resistant material. Regrettably, There's not much to be found in literature or on the net about PTSA and suitable materials (except that aisi 316 is not the ideal material).

Is there a source of information I'm overlooking? Or has anyone an idea of what we can expect?

[The major idea behind this question is this:
In earlier days materials choice was a process of trial and error. Now that we see that there more problems even with duplex materials, I like to have more background information about PTSA and the attack of metals by PTSA.
So this question is mainly to put me on track, in the direction of one group of materials (e.g. Nickel-alloys).
After that I can start choosing the best by performing specific tests.]

I thank you all.

 

[PVRV]

1. PREN = Cr% + 3.3xMo + 16xN > 40 provides,

1.1 Critical Pitting Resistance > 40 C approx
1.2 Critical Crevice Resistance > 30 C approx

Take a look at SS --> DSS --> SDSS taking the above into
consideration.

2. Refer to ASM Volume 13 for guidance.

3. CRA are expensive and require proper welding
qualification. Take a look at Inconel 600
and any grade of hastelloy; cost is a factor
I believe gold plateing is almost as expensive
as Hastelloy C276.

4. Worth While to evaluate non-metallic materials.

Cheers

 

[ghopkins]

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 these results are from actual testing from a company called Symalit AG (Switzerland). They take the thermoplastic pellets (from Dupont for example) and extrude them into 1.25 meter wide rolls. The thickness is 2.3mm to 4 mm (depending on the material) - this is fiber free thickness. During the extrusion process, Symalit presses a fabric backing into the sheet. This fabric packing, either glass knit or polyacrylinitrile knit, provides the mechanical bond to the substrate (usually corrosion resistant fiberglass). I can provide more detail about this fabrication process to you separately, but it works very well for piping systems and vessels.

If you want to contact Symalit, the person to talk to is Arek Blazejewski. His phone # is 610-695-8445. He can refer you to vessel manufacturers and piping manufacturers.

For some reference, an FEP-Teflon lined fiberglass tank will run approximately the same cost as Titanium (Grade 2) - pretty far from 316 stainless.

There's a company in Alabama called NMR (Non-Metallic Resources) that makes FEP lined piping systems that are very economical (relatively speaking) and are of high quality.

Lastly - don't let thermoplastics and fiberglass deter you . They are capable of temperatures to 350F and pressures of 150 psig (and higher). There are even ASME codes and standards for this type of construction. ASME RTP-1 covers full vac up to 15 psig and ASME Section X covers >15 psig (just like Section VIII, except for fiberglass). I should point out that these standards apply to vessels only and not piping systems. I'm not sure what standards (if any) apply to piping systems using this type of construction.

Let me know if you want me to fax or email you the copy of the Symalit brochure, but I would recommend calling Arek.


Greg
ghopkins@rl-industries.com

 

[kenvlach]

You haven’t mentioned T or P, but for higher T & P, use plastic-lined pipe and fittings. Four major manufacturers are
DOW,
Peabody/Doré
Plastic Omnium
Resistoflex
according to Corrosion Control in the Chemical Industry (1986).

The Resistoflex site shows the chemical resistances of various liners vs. sulfonic acids:

Maximum Temperature for Liner:
Polypropylene PVDF PTFE
Corrosive Stream °F °C °F °C °F °C
Aryl sulfonic acids 150 65 -- -- 450 230

Benzenesulfonic acid 75 25 125 50 450 230

Chlorosulfonic acid (100%) NR NR NR NR 450 230

Methane sulfonic acid 125 50 200 95 450 230

Phenolsulfonic acid (65%) -- -- 125 50 450 230


You might contact them for specifics for p-toluene sulfonic acid at

http://www.resistoflex.com/chooseliner.asp

 

[scorcher]

This is what we use on site for TSA. NICKEL-COPPER ALLOY (MONEL 400) SEAMLESS ANNEALED PIPE MADE TO ASTM B 165. N04400 (N1/CU) SCH40S

or
ASTM F423 (PTFE) OUTER API gr.B SC40. LINNER ASTM D1457 TYPE I

If you are still interested, I can check what we use on our PTSA plant?

Perhaps you could talk to your supplier?