• Accurate pH Measurement of Refinery Wastewater

Measurement and Testing

Accurate pH Measurement of Refinery Wastewater

Jan 07 2015

Refinery wastewaters contain challenging contaminants such as residual hydrocarbons, sulphur and chloride salts from sour crude refining, ammonia, cyanides, hydrofluoric acid, benzine and toluene.

To eliminate these contaminants, the waste waters are subjected to a coagulation process where Alum and polymers are added - these create a ''floc' that reduces the contaminates to a sludge.  Accurate pH measurement and control is necessary to optimise the coagulation and floc.

Bio-reactors remove VOC's - bacteria converts the VOC's to a non-hazardous sludge - Again Precise pH measurement and control is necessary to optimize this biological process. 

Challenges for pH/mV sensor include fouling of the porous reference junction is the main cause of high levels of maintenance and electrode failure, and H2S poisoning of the Ag/AgCl reference half cell and electrolyte occurs due to a precipitation between the H2S and AgCl - this forms AgS that completely blocks the reference junction and wrecks the mV stability of the Ag/AgCl half cell. 

Refex (USA) pH and ORP electrodes offer a solution to the pH problems of the past, with the New and Patented NON-POROUS reference interface that has replaced the now obsolete porous reference junction.  This interface provides a separating barrier between the sour waters and the electrode's Ag/AgCl half cell and KCl electrolyte - hence there is no liquid contact or exchange between the contaminated waters and the electrode's reference half cell.

The accurate and low maintenance Refex EC-3/4"-2001-Pt1000-LE-10m gives fast responses to pH change, and combine a long-life with chemical savings (No over-shoot beyond pH High/Low set points), resulting in big savings for your operation.

Two specifications are available – the Refex Electrode Type EC-3/4-2001-Pt1000-LE - 10m cable (other cable lengths available on request) 3/4" All in One Combination, and the IMPP - Polypropylene DIP Immersion System - 1m long (Longer lengths available). 

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