Scale and Corrosion Prevention in Cooling Water Systems Part I : Calcium Carbonate
This paper presents the results of study that was undertaken to investigate the ability of a new antiscale, polyacrylamide in solving problems found in cooling water systems. The effects of the polymer on C-steel and copper dissolution in synthetic cooling water environment were studied through scale, Tafel, and Linear polarization measurements. The results obtained from this study showed that the new antiscale polymer can decrease scale build-up growth under experimental conditions. Both linear and Tafel polarization studies indicate that the polymer acted as an anodic type corrosion inhibitor on C-steel and mixed-type on copper, thus reducing metal dissolution. Morphological investigations of calcium carbonate deposits on both C-steel and copper surfaces were studied by optical microscopy. The polymer used in this study appears to have an excellent crystal modification effect on reducing calcium carbonate scale. The antiscale effect results from changes in crystallization behavior promoting bulk solution precipitation rather than formation of adherent scale.
A Novel Biodegradable Poly (Hydroxybutanedioic Acid-co-2-hydroxypropane-1,2,3-tricarboxylic Acid) Copolymer for Water Treatment Applications
Minimizing the formation of inorganic scale deposits in industrial water continues to be a challenge for water treatment systems. In order to meet this challenge a novel biodegradable poly (DL-malic acid-co-citric acid) copolymer, effective in providing calcium carbonate scale inhibition was developed. Synthesis and characterization of the biodegradable, water-soluble and polyester copolymer was performed. Synthesis was done by direct bulk melt condensation in the absence of a catalyst above 150°C. Characterization of the copolymer was carried out using infrared absorption spectra (FTIR), differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) equipment. In the present work the precipitation of calcium carbonate from relative supersaturated solutions at different weight ratios of comonomer inhibition rates have been studied. The results indicate that the copolymer is an effective calcium carbonate descaling inhibitor that suppresses the growth process against calcium mineral scale deposits.
Investigation on fouling behaviors of low-energy surface and fouling fractal characteristics
Although many measures have been taken to mitigate the formation of deposits on the heat transfer surface, fouling is still a serious problem in industrial processes. This article describes the fouling behavior of two types of copper-modified surfaces with low surface energy. CaCO3 crystallization fouling experiments were carried out on the modified heat transfer surfaces in a simulated cooling hard water system. The results suggest that the fouling process is enhanced in the presence of desorbed air bubbles on the modified surfaces. The fractal theory is used to analyze the fouling geometric texture. The results demonstrate that the fractal dimension values D of CaCO3 fouling on the modified surfaces are higher than that on the copper surface.