Research on composite scale inhibitors for inhibiting calcium carbonate scaling in high temperature geothermal fluid

Geothermal energy is a crucial renewable resource for achieving carbon neutrality. However, its exploitation is hampered by scaling, particularly calcium carbonate (CaCO 3 ) deposition in wellbores. To address this, a novel composite polymer scale inhibitor was synthesized via the copolymerization of five monomers: acrylic acid, hydroxyethyl methacrylate, sodium allyl sulfonate, citric acid, and monosodium glutamate. This molecular design enables the synergistic integration of multiple functional groups (carboxyl, sulfonic, hydroxyl, ester, and amide). Fourier transform infrared spectroscopy confirmed the successful incorporation of these groups, and thermogravimetric analysis demonstrated excellent thermal stability. Evaluation experiments revealed that the copolymer serves as a highly effective scale inhibitor under simulated high-temperature geothermal conditions (150–200 °C), achieving an inhibition rate exceeding 96% against CaCO 3 scaling. This work presents a promising and sustainable solution for scaling control in challenging geothermal environments.