LNG plant cooling water outlet free chlorine content is slightly high. However, soduim hypochlorite injection at cooling water intake is as per design.

 

Well, it is likely that the actual chlorine demand is less than the design value. That happens. Turn down the metering pump. If it is flow paced, reduce the pump stroke so less chlorine is injected per pulse of flow. If there isn¹t an analyzer, you might want to put one in, and record the residual consistently, so you can see when the demand varies.

The simple answer is turn the chlorine feed rate down until the chlorine residual is what you want it to be.

Walt

Walt Boyes, Life Fellow, ISA; Fellow InstMC
Chartered Measurement and Control Technologist
Spitzer and Boyes LLC

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