Preparation and evaluation of nonphosphate terpolymer as scale inhibitor and dispersant for Ca₃(PO₄)₂, BaSO₄, and Iron (III) hydroxide scales

Abstract

The polymeric scale inhibition and dispersion agents (PAYS) were prepared by graft copolymerization of acrylic acid, allylpolyethoxy carboxylate (APEY) and 2-acrylamido-2-methyl-propanesulfonic acid by using ammonium persulfate as a radical initiator in aqueous solution, among which APEY was synthesized in laboratory. Structure of PAYS was characterized by Fourier transform infrared spectroscopy. Experimental data showed that the terpolymer was a high-efficient chelate sorbent, and it exhibited excellent ability for calcium orthophosphate, with approximately 96% efficiency at the dosage of 4 mg/L, as well as high efficiency toward barium sulfate scales nearly 80% inhibition. The effectiveness of PAYS depends on the agent concentration, temperature and the ratio of the reactant. The formation of Ca 3 (PO 4 ) 2 and BaSO 4 precipitates was characterized by scanning electron microscopy. It appeared that the crystal shape, size, and the morphology of scale changed apparently at the dosage of 4 and 15 mg/L, respectively. In addition, it has good effect on controlling iron (III) scaling. This study was also devoted to the understanding of the action mechanism of these inhibitors in suppressing the crystal nucleus formation and preventing the crystal growth. Based on the contrast experiment of scale formation, the supposing mechanism diagram was also delineated and analyzed in detail.

High-Efficiency Terpolymer Scale Inhibitor for Obstructing the Formation of Calcium Sulfate by Preventing Crystallization

“…According to the literature, the water solubility and temperature resistance of the copolymers may strengthen due to the introduction of the sulfonic acid group with strong electronegativity. 39,48 Following that, the initiator content and molecular regulator content will be explored to choose the optimal conditions for preparing the copolymer with the best scale inhibition performance. A suitable APS content was vitally important for improving the scale inhibition performance of the copolymer.…”

“…In addition, the introduction of the sulfonic acid group will also increase the charge density, resulting in the fact that the polymer penetrates the hydration layer around calcium and sulfate ions and gets adsorbed on the active growth sites of the crystal lattice. 39 Meanwhile, the temperature resistance of the copolymer was also enhanced due to the presence of the sulfonic acid group. Thus, the inhibition efficiency of the copolymer can be enhanced with the introduction of sulfonic acid and amide groups.…”

Synthesis, characterization and properties of a novel environmentally friendly ternary hydrophilic copolymer

“…CaCO 3 scale is one of the most common scales in oil and gas production systems, and calcium scale is usually found in underground equipment, pipelines, valves, wellheads, and other places. 3,4 Scaling can easily damage oil production equipment and transmission pipelines, which seriously affects the normal production of oil and gas elds. 5 Especially in low permeability elds, scaling can block reservoir pores, causing reservoir permeability to decrease and injection pressure to increase, resulting in under-injection of injection wells, which leads to a decrease in oil production.…”

Effect of PAAT as an Environmentally Friendly Terpolymer on the Scale Inhibition of CaCO3 in Artificial Seawater: Chemical and Electrochemical Study

“…However, carboxylic groups alone may show low dispersibility, affecting the inhibitor performance . The existence of ether and sulfonic acid groups, due to their hydrophilicity nature, increases the dispersion property of inhibitors. ,, Therefore, some researchers claimed that using the polymeric inhibitors containing various functional groups (copolymers or terpolymers) can provide a better efficiency against scale formation. , However, Amjad evaluated the effect of different polymeric inhibitors on the inhibition of gypsum scaling, while a moderate inhibition efficiency was reported for terpolymers, e.g., poly­(acrylic acid:2-acrylamido-2-methylpropane­sulfonic acid: tert -butyl acrylamide) (AA-AMPS-TBAA) relative to some homopolymers. This discrepancy may arise from the difference in the type of scale, scaling media, and even the analysis method.…”