Refinery Waste Waters – pH Measurement and Control

Refineries processes produce large volumes of highly contaminated waste waters. Typical pollutants being: Residual Hydrocarbons; Hydrogen Sulphide and chloride compounds  (heavy sour crude refining); Cyanides from fluid catalytic crackers and cokers; Hydrogen Fluoride from Alkalization processes; Volatile Organic Compounds – Toluene and Benzene; Coagulation/Flocculation chemicals

pH measurement and correction is essential to reduce the effects of corrosion (corrosion costs O+G industry USD Billions/year).

pH Measurement and correction by the addition of dosing chemicals typically NaOH and HCl to keep effluent out-fall discharge within EPA compliant levels are essential for environmental protection  – Failure to comply with EPA discharge compliant results in heavy EPA penalties sometimes running into USD millions.

Problems with Conventional pH sensors with POROUS ‘Wet-Ends’ are fouling and poisoning of the electrode’s reference half-cell – these electrodes degrade rapidly especially where H2S sour waters are present (almost everywhere ) the electrode can die in a few days – oily deposits foul up the Porous reference junctions (wood,ceramic,porous Teflon, single capillary) – resulting time wasting cleaning and recalibrations to remove these degrading deposits.

The patented Refex pH/mV electrodes are unique and totally resistant to all refinery poisoning and fouling problems (corrosion and environmental). The unique difference between porous and Refex Non-Porous is the Refex solid-state non-porous ionically conductive polymeric junction/interface that separates the process from the electrodes Ag/AgCl half cell and KCl electrolyte. There is no contact or exchange of liquids – making it impossible to foul or poison the Refex electrode. Coating deposits/coatings on the outside surface of the Refex electrode must remain wet and conductive.

The Refex electrodes in all O+G refinery applications (also ethylene plants) remain accurate with minimum maintenance often 10 times longer life compared to all others. The Refex electrodes having a NON-POROUS ‘Wet-End’ are also resistant to high and varying temperatures and pressures.

The Refex electrodes are compatible with all EX pH transmitters and are available designed to retrofit to existing installations (flow cells-Retractable-Tank DIP systems).

Refex offers a free consultancy service to study the requirements of all applications and also offers a free 90 day Try-It/Like-It/Buy-It for new customers and existing customers with new applications.