Presence of chloride chloride Cl- in water recovered from steam reforming 1

[pb-2020]

Hi
In a methanol plant, the bottom stream of Saturator equipment shows in its water analysis, the presence of chloride ion less than 1 ppm. Why is the chloride ion generated?

Result of sample parameters:
pH: 4.3
Conduct: 1520 uS/cm
TOC: 1100 ppm
Cl-: 0.3 ppm

NaOH its injected in the distillation unit and part of this remainder water (15 ton/h) its inlet stream of saturator equipment.

 

[EdStainless]

It is in one of your input streams. What is the flow in this bottom stream? It is likely that 99% of your Cl is ending up here, so in it's source material it may be 10ppt.
And why is the pH so low? Has this water been de-gassed?

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P.E. Metallurgy

 

[moltenmetal]

No NaOH I've ever encountered was 100% free of Cl-, so that'd be the first place I'd look, unless I misunderstood your flowsheet.

Next guess is that it's an analytical artifact. What analytical method was used to detect 300 ppb of chloride reliably, and what is its detection limit?

 

[pb-2020]

What is the flow in this bottom stream?
R: 240 Ton/h
And why is the pH so low? Has this water been de-gassed?
R: The bottom stream it is recirculated to the Saturator. A part of this stream it is Blowdown. The pH is Low, because the stream it has not been de-gaseed yet.
Water entering the Saturator comes from two sources:
1) H2O remnant from distillation
2) H2O condensate of Reformed Gas.
I presume that the source of Cl- comes from the NaOH product that is injected to distillation and concentrates on the Saturator. Is it possible?

 

[pb-2020]

There is stainless steel piping. What temperature is dangerous for the material if I have a current with 1-10 ppm of Cl-?. Or it doesn't matter?

 

[Latexman]

Which SS? There must be hundreds of grades of SS.

Good Luck,
Latexman

 

[pb-2020]

304L

 

[EdStainless]

At this low of pH SCC is a real risk with 304.
What else in in this stream?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy

 

[williamhakespeare123321]

What is the flow in this bottom stream?
R: 240 Ton/h
And why is the pH so low? Has this water been de-gassed?
R: The bottom stream it is recirculated to the Saturator. A part of this stream it is Blowdown. The pH is Low, because the stream it has not been de-gaseed yet.
Water entering the Saturator comes from two sources:
1) H2O remnant from distillation
2) H2O condensate of Reformed Gas.
I presume that the source of Cl- comes from the NaOH product that is injected to distillation and concentrates on the Saturator. Is it possible?

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Degreaser