Method for analysis of chloride ions in steam condensate
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In the production of urea by CO2 stripping method, it is necessary to analyze the chloride ion content in the steam condensate on the shell side of the high-pressure ammonium methane condenser. The main purpose is to prevent the accumulation of chloride ions in the condensate and cause equipment corrosion. Normally, we analyze once per shift, using spectrophotometry. The measured chloride ion content is generally less than 1 mg/L. However, after several years of operation, the equipment leaked, and it was determined that it was still intergranular corrosion caused by chloride ions. This condensate is produced by the direct condensation of steam. I would like to ask experts, is our analysis method correct? Can it be changed to silver nitrate titration?
Determination of chloride in water quality Silver nitrate titration method GB11896-89 Determination of free chlorine and total chlorine in water quality N, N-diethyl-1,4-phenylenediamine titration method GB11897-89 Determination of free chlorine and total chlorine in water quality N, N-diethyl-1,4-phenylenediamine spectrophotometry method GB11898-89
Our company has stainless steel steam coils, and it is required that chloride ions should not exceed 200PPM, that is, 200Mg/l. We measure chlorine using spectrophotometry versus candlepower, which is definitely more accurate than titration.
It’s also possible that the chlorine level measured outside the condenser tube exceeds the standard.
If there is no problem with the analysis, it is recommended that you go to the material area to consult the analysis method provided by the moderator. The measurement method you are using are both classic methods, so there should be no problem with the analysis.
For such a low concentration of chloride ion content, the titration method is analytically inaccurate, and the photometric method you are using now is fine. Look for problems with the workmanship and trust yourself.
This phenomenon has also occurred in our factory. We used low-concentration silver nitrate titration, but the color of the result was not easy to judge.