Seawater Dechlorination Analyser is an Accurate and Economical Chlorine Measurement Solution

The new Model DCA-23 Seawater Dechlorination Analyser from Electro-Chemical Devices (USA) is a low maintenance measurement solution that requires no chemicals to monitor seawater chlorine levels accurately in a wide range of industrial process and municipal water treatment applications.

Seawater has multiple process industry uses, including heat exchange systems at LNG terminals, oil/gas refineries, electric power plants and SWAC systems (salt water air conditioning) in commercial buildings. Seawater desalination plants also chlorinate and dechlorinate the water before processing. The chlorination of seawater inhibits the growth of marine life on the various filters, screens and heat exchanger surfaces, but the seawater must be dechlorinated for environmental reasons before it is discharged back into the original water supply.

The DCA-23 is a single-purpose analyser that monitors chlorine in seawater from 0.0 to 2.00 ppm. It features an economical, low-maintenance design that requires no chemicals. It measures the pH, temperature and Total Residual Oxidant (TRO) of seawater and converts them into an equivalent ppm chlorine value, which is displayed to conform with existing conventions. It features a minimum detection limit (MDL) of 0.014 ppm and a limit of quantification (LOQ) of 0.044 ppm, making the DCA-23 Analyser suitable for monitoring in environments with the most stringent dechlorination regulations.

The DCA-23 features three sensors, pH, TRO and temperature. The pH sensor measures from 0-14 pH, the TRO sensor measures from ±1500 mV and the temperature sensor measures from 0-100°C. The DCA-23 with its tri-parameter monitoring, is the ideal seawater chlorine analyser for a wide range of applications.

During the re-gasification process at LNG terminals, large quantities of chlorine-treated seawater are used to heat the LNG heat exchangers. Seawater gradually raises the temperature of cold liquid natural gas changing it from a compressed fluid into a gas for distribution through the service pipelines. Recycling the seawater requires dechlorination monitoring with the DCA-23.

Steam-driven turbines at electric power plants generate much of the world’s electricity. Seawater cooling is employed at both thermal and nuclear power plants in coastal regions. The seawater flows over heat exchangers and condenses the steam used to drive the turbines. The cooling is accomplished with chlorinated seawater, which requires monitoring with the DCA-23 before discharge. Similar heat exchange processes are utilised by oil/gas refineries. 

In water desalination plants, seawater is treated by reverse osmosis (RO) to remove the salt. The intake seawater is treated with chlorine to kill algae and other organisms prior to the reverse osmosis process. The RO membranes are degraded by chlorine so the chlorinated seawater must be dechlorinated before contacting the membranes. The DCA-23 is ideal for monitoring the dechlorination process.

The DCA-23 Seawater Dechlorination Analyser is available in five configurations: 1.)  Loop powered, 4-20 mA = 0.00 to 2.00 ppm Cl; 2.)  24VDC powered with two 4-20 mA outputs, Cl and pH; 3.) 24VCD powered with two 4-20 mA outputs and two alarm relays; 4. ) 110 VAC powered with two 4-20 mA outputs and two alarm relays; and 5.) 220 VAC powered with two 4-20 mA outputs and two alarm relays. The maximum system pressure and temperature rating is 50 psig at 60°C.

The DCA-23 Seawater Dechlorination Analyser is an easy to install plumb-and-play device when ordered as a complete Uni-Strut rack mounted system and it is also available as separate components. The rack mounted system is plumbed with ¾” schedule 80 pipe, with slip fittings for input and drain. The T-23 Analyser, 2 sensors, pH flow cell and TRO flow cell are rack mounted using 1⅝”x1⅝” Uni-Strut rail.