Calcium Carbonate Scale Formation in Copper Pipes on Laminar Flow

^a Department of Mechanical Engineering, Muhammadiyah University in Semarang, Indonesia
^b Departement of Mechanical Engineering, Diponegoro University, Semarang Indonesia
^c Department of Chemical Engineering, UNTAG University in Semarang, Semarang Indonesia

^* Corresponding author. Tel. +62-8164242537, +62-8445768
E-mail address: samraharjo2@gmail.com
E-mail address: apbayuseno@gmail.com

Abstract

Calcium carbonate is commonly precipitated as a scale in the transportation pipes of water. The presence of this mineral deposit becomes problematic, because it can block the pipes and lead to a decline in piping performance. Calcium carbonate precipitation from the synthetic solution was experimentally investigated in the present study. The aim of research was to predict the occurrence of precipitates and characterize the scale precipitated from the solutions. The synthetic solutions were prepared using CaCl₂ and Na₂CO₃, which was mixed with distilled water (H₂O). The concentrations of Ca²⁺ at 2000, 3000, 4000 and 5000 ppm. in the solution were adjusted and the solution flow in the Cu pipes at the different flow rate of 30, 40 and 50 ml/min. It was found that in all the experiments, the conductivity decreased abruptly after a certain induction period. Higher temperature produced more mass of the scale indicating that the increasing temperature promote scale formation. SEM analysis showed that the scale was rhombohedral, while EDS revealed that the elemental composition of the scale consisted of Ca, C and O. The crystalinity of the scale was found to be mostly calcit as shown by the XRD