US 12,007,369 B2
Residual corrosion inhibitor monitoring
Talal M. Al-Ghamdi, Dhahran (SA); Muhaned M. Feghia, Khobar (SA); Faisal M. Mutahhar, Dhahran (SA); and Musab M. Talal, Dhahran (SA)
Assigned to Saudi Arabian Oil Company, Dhahran (SA)
Filed by Saudi Arabian Oil Company, Dhahran (SA)
Filed on Apr. 1, 2021, as Appl. No. 17/220,505.
Prior Publication US 2022/0317096 A1, Oct. 6, 2022
Int. Cl. G01N 30/06 (2006.01); G01N 30/12 (2006.01)
CPC G01N 30/06 (2013.01) [G01N 2030/062 (2013.01); G01N 2030/065 (2013.01); G01N 2030/121 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method for determining corrosion inhibitor residual concentration of dry crude oil, the method comprising:
mixing the dry crude oil with a standard solution to form a first mixture, the standard solution comprising a corrosion inhibitor in a known concentration;
mixing the first mixture with an aqueous saline solution to form a second mixture, the aqueous saline solution comprising about 1% salt concentration or greater;
agitating the second mixture for about 1 hour or longer and at a temperature of about 50 degrees Celsius (° C.) or greater;
after agitation, allowing a hydrocarbon phase and an aqueous phase of the second mixture to separate;
obtaining a portion of the aqueous phase; and
analyzing the portion of the aqueous phase with reversed phase liquid chromatography using a mobile phase having a mixture of methanol to phosphate buffer at a 1:1 ratio and a pH of about 2.5 to determine a corrosion inhibitor residual concentration of the dry crude oil.