Fouling characterization of calcium carbonate on heat transfer surfaces with sodium carboxymethyl cellulose as an inhibitor

Fouling via the deposition of calcium carbonate (CaCO3) on heat transfer surface reduces the heat transfer efficiency and compromises the stable operation of the heat exchanger. Sodium carboxymethyl cellulose (SCMC) as a fouling inhibitor effectively prevents the growth of CaCO3. In this work, the fouling characteristics of a heat transfer surface by CaCO3 with the SCMC inhibitor were studied experimentally; the effects of the SCMC concentration, inlet temperature of the solution, mass flow, SCMC degree of substitution, and SCMC viscosity on fouling inhibition were investigated. Moreover, the asymptotic fouling thermal resistance and fouling inhibition efficiency were analyzed by varying the operation conditions and the physical properties of SCMC. The results show that the fouling thermal resistance decreases with increasing SCMC concentration, degree of substitution, and solution temperature, and increases with increasing mass flow of the solution. However, the effects of the SCMC viscosity varying from 600 mpa.s to 15000 mpa.s on fouling thermal resistance were observed to be negligible. Additionally, there was significant variation of the CaCO3 fouling morphology with a change from calcite particle to an irregular sphere after the addition of inhibitor.