Inhibition of CaCO₃ scaling on heat exchanger surface with green functionalized graphene nanoplatelets (GGNP) coating

Fouling in heat exchangers (HXs) systems is a critical global concern that compromises energy efficiency, increases greenhouse gas emissions, and raises operational costs across industrial sectors. Therefore, any solution for the retardation or elimination of scaling on HXs surface will provide considerable economic and environmental advantages. Conventional CaCO₃ scaling mitigation strategies such as chemical treatments, physical methods, and surface coatings have shown better effectiveness but are often constrained by high material costs, environmental risks, and limited scalability. This study uses the electrophoresis technique to investigate the application of green functionalized graphene nanoplatelet (GGNP) coatings on stainless steel 316L HXs surfaces. This technique offers high material coating efficiency, rapid coating process, and precise control over deposition. An accelerated fouling experiment was conducted over 72 h under specific condition (300 ± 25 mg/L CaCO₃, 2.5 LPM flow, 60 °C). The GGNP-coated surface demonstrated a 73.94 % reduction in CaCO₃ deposition, with nearly zero fouling resistance and a ∼45 % improvement in overall heat transfer coefficient. The analysis indicates that the application of GGNP coating on heat exchanger surfaces can lead to a cost saving of approximately 5,953.12 USD per megawatt annually. Additionally, the environmental assessment shows a significant reduction in harmful emissions, with estimated decreases of about 2.034 tons of CO₂, 0.04 tons of SO₂, and 0.0462 tons of NO_x per megawatt each year. These improvements contribute immensely/greatly towards achieving Sustainable Development Goal (SDG) 7.3, which aims to enhance energy efficiency.