Preparation of a phosphorous-free terpolymer as a decalcifying agent for removing calcium from crude oil

Abstract

A novel phosphorous-free terpolymer, used as a decalcifying agent for removing calcium from crude oil, was prepared through free-radical polymerization reaction of acrylic acid (AA), allylpolyethoxy amino carboxylate (APEA), and 2-hydroxyethyl acrylate (HEA) in water with ammonium persulfate as initiator. Structure of the synthesized AA-APEA-HEA terpolymer was characterized by Fourier transform infrared spectrometer and 1H Nuclear magnetic resonance ( 1 H-NMR). AA-APEA-HEA was used to remove calcium from Luning pipeline crude oil. The effects of several factors, such as molar ratio, dosage and reaction temperature on calcium removal efficiencies from crude oil were evaluated. The results indicated that removal of calcium from crude oil using AA-APEA-HEA was far more efficient than that using AA-APEA, PAA, HPMA and PESA under the same conditions. The optimum conditions for calcium removal from crude oils were as follows: (a) molar ratio of AA-APEA-HEA was 2:1:0.5, (b) dosage of AA-APEA-HEA was 100 ppm, and (c) reaction temperature was 100 ℃. Under these conditions, the removal efficiency of calcium from Luning pipeline crude oils was approximately 98.63 %. Furthermore, the proposed decalcification mechanism suggests the surface complexation and chelation between the functional groups of carboxylic (-COO -) 2 and amino (-NH 2 ) and Ca 2+ , with polyethylene glycol segments increasing its solubility in water and lipophilic ester groups increasing its affinity to oil.

Development of a Novel Terpolymer as a Green and Efficient Decalcifying Agent for Crude Petroleum

“…As shown in Figure , the esterification of the surface hydroxyl groups of APEG was realized with l -aspartic acid according to our previous works. , Typically, 0.1 mol of l -aspartic acid was dissolved into 30 mL of water (pH = 3), and the above l -aspartic acid solution was loaded into a three-necked flask, which was placed in the microwave reactor (MCR-3, 900 W). Then, 0.1 mol of APEG was added into the l -aspartic acid solution.…”

Comprehensive demetallization of crude oil using spherical polyelectrolyte brushes with submicron polybutadiene latex as a core

“…If the metals are not effectively removed, they will cause serious problems, such as the deactivation of the catalyst during the processing of crude oil, 5 the corrosion of the oil refining equipment, 6 and the deterioration of middle and downstream product quality 6,7 . Among them, calcium and iron are mostly present in crude oil in the form of oil‐soluble organic salts, 8 which can be stably chelated with the aromatic hydrocarbon system in crude oil 9 through the π–π chemical bond and are difficult to be removed 10 . Besides, nickels in the form of oil‐soluble porphyrin 11 or non‐porphyrin complex, 12 are mostly present in the resin or asphaltene, 13 which is more difficult to be removed through the traditional electric desalination process 14,15 .…”