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In our distillation column we are treating Natural Gas Condensate with 76 ppm sulphur, Acidity < 0.05 mg KOH and organic chloride <0.3 ppm and water content < 0.05%. but designer did not keep any caustic, corrosion inhibitor and Ammonia dosing provision due to combat corrosion at overhead line. Also they did not keep any DM water flushing provision (for fouling control within the tubes of aero condenser). Is it ok not to keep above provision as per above spec of NGC or NGL? But we are draining the overhead drum water separating boot approximately 10-15 litres per day where PH remains 5 to 5.5. So, do we need to use NH3, Caustic and corrosion inhibitor in order to keep PH more than 6? Moreover, do we need to inject DM water at the up stream of Air cooler to eliminate fouling problem as well as increasing PH by the dilution of DM water?
 
Answers
24/03/2019 A: Feroz Ahmed, Petromax Refinery Ltd, feroz_erl94@yahoo.com
Should the water injection rate should be 1-2% of total overhead flow rate? If not then what should be the actual rate?
14/12/2018 A: NS Murthy, Suez, murthy.ns.ext@suez.com
Pl get the boot water analyzed for species like H2S; Organic acids, if any; HCl; CO2; etc. As such 5+ pH is good enough as long as there is no HCl in OH. Also, check the level of total Fe in the boot water. It is possible a simple additive treatment will be adequate for a lasting solution on OH system asset integrity. Pl contact the nearest Suez representative or send a mail to us murthy.ns.ext@suez.com.
12/12/2018 A: Sam Lordo, Nalco Company, salordo@comcast.net
i would do a detail water analysis to determine of the pH depression is due to CO2, or organic acids ( common for condensates) , if that is the case then either a water was h or addition of a filming amine would probably be all of the protection you need ,, if you have organic acids in place then adding neutralizer like ammonia will create more problems