Modern Analytical Technologies for Dechlorination Optimization, Monitoring and Control

Modern Analytical Technologies for Dechlorination Optimization, Monitoring and Control Vadim Malkov, 03/07/2024, 8:45AM Current Analytical Technologies for Chlorine Monitoring Analytical Measurement Principle Main Benefits Major Deficiencies Technology Electrochemistry (potentiometry) Continuous Indirect, non-specific Oxidation– mV output proportional to Fast response to appearance of Calibration dependent reduction change in the sample oxidation oxidants Matrix influence (sample pH, flow, potential pressure, etc.) potential Reagentless Slow response to excess of reducers (ORP) Electrochemistry (amperometry) Continuous Online only – mA output proportional to Fast response to chlorine Calibration dependent Amperometry chlorine concentration changes Matrix influence Reagentless “Sleeping” effect Colorimetry (DPD) – change in Direct and accurate Non-continuous (batch analysis) color intensity proportional to Stable calibration Reagents Colorimetry chlorine concentration. Independent of sample conditions Lab and online measurements Intensity of the light emitted by Direct and accurate Grab sample analysis only the analyte after excitation at a Independent of sample Narrow measurement range Fluorimetry shorter wavelength conditions Reagents Highly sensitive and selective Online amperometric sensing technology is not equal to amperometric titration Colorimetric Online Technology Chlorine breakthrough: ORP delay time ~12 min CL17 delay time ~25 min SBS feed restored: CL17 responded immediately ORP – long delay… Colorimetric analyzer: T – reaction complete (e.g. 150 100 sec for CL17/CL17sc), independent of pH, flow/pressure, etc. Colorimetric Online Technology Amperometric sensors: T or T – response time to 90 or 90 95 95% accuracy (e.g. 60 – 120 seconds), dependent on calibration, pH, flow/pressure, etc. LOD/LOQ Determination 60 50 40 30 20 10 0 0 10 20 30 40 50 Derived: LODs for the new ULR analyzer = 8 µg/L (ppb), fluorimeter ~ 2.5 µg/L (ppb) of total chlorine )bpp( enirolhC latoT derusaeM Calibration Curves for ULR Chlorine Methods ULR DPD Colorimetric Analyzer Fluorescence Handheld Amperometric Titration Benchtop Spectrophotometer Linear (ULR DPD Colorimetric Analyzer) Linear (Fluorescence Handheld) Linear (Amperometric Titration) Linear (Benchtop Spectrophotometer) Chlorine Standard (ppb) Agenda Methods Overview ORP vs Colorimetric Amperometric vs Colorimetric LOD & LOQ Standard Methods & Fluorimetry for ULR chlorine  Field Studies Conclusions Conclusions “ “ You can’t control what you do not measure accurately  The value of choosing the right analytical method for dechlorination control is undisputable.  The accurate chlorine measurements supported significant savings elucidated by the analytical instrumentation.  The direct and indirect savings encompassing chemical and labor cost, prolonged RO membranes life, assurance of produced water quality, and overall decrease of maintenance provide enough reasons to adopt the right analytical instrumentation for dechlorination optimization.