CaCO3 Scale formation on Surface Initiated Polymer brush for Heat exchanger Application

Inorganic fouling is one of the challenging problems in heat exchanger applications. One approach to mitigate fouling is to employ surface coatings. In this study, we evaluated the feasibility of surface initiated polymerization (SIP) as thin coating technology to mitigate CaCO3 formation for heat transfer applications. The extent of formation of CaCO3 on different types of poly(oligoethyleneglycol) methacrylate brushes (POEGMA) was investigated under stagnant and flow heat-exchanging conditions. Polymer brushes of high graft density reduced the surface coverage of CaCO3 more effectively than the low graft density brushes. By contrast, the thickness of the brush did not correlate with the surface coverage of CaCO3. The comparison of stagnant and flow experiments revealed that the antiscaling effect of POEGMA brushes originate due to reduced adhesion of CaCO3. Finally, the SIP process was successfully scaled-up to coat commercial heat exchanger plates with thickness and homogeneity comparable to lab-scale surfaces. Under industrial testing, the POEGMA brushes extended the performance by 50 h before the commencement of complete blockage.