Factors Affecting Scale Formation in Sea Water Environments – An Experimental Approach

Abstract

Sea water is a complex aqueous environment with a large tendency for scale formation, which is usually ascribed to scaling from dissolved salts and suspended particles. Scale formation is causing many problems in thermal processes such as desalination and steam generation plants. In a typical desalination plant, ca. 40 % of the heat transfer area is provided to allow for scale formation problems, which is equivalent to a ca. 10 % increase of the whole capital cost of the plant. The main constituents forming scale in sea water environments, i.e., calcium carbonate, calcium sulfate and magnesium hydroxide, are extensively investigated in the present work. In order to obtain a better understanding of the scaling tendency of the seawater environment, an experimental unit was precisely designed and coupled with a data acquisition system for continuous monitoring of the investigated parameters. Significant factors affecting scale formation such as concentration of salts, flow velocity, water temperature and pH of the environments were studied at length using mild steel and stainless steel (smooth and rough). Hydrodynamic parameters such as Reynolds number and shear stress were used in the analysis of the collected data and revealed the role of shear stress in the effective removal of scale. The Kern-Seaton scale model was used to calculate the fouling resistance in each case and the values obtained were compared with the experimental results. A modification of this model was also undertaken to provide better agreement with experimental findings.

Removal/Dissolution of Mineral Scale Deposits

“…Heterogeneous nucleation sites include surface defects such as pipe surface roughness or perforations [8] in production liners or even joints and seams in tubing and pipelines as shown in Figure 29.3. Heterogeneous nucleation on surfaces is energetically more favorable than homogeneous nucleation.…”

Surface inorganic scale formation in oil and gas industry: As adhesion and deposition processes

“…In developing a surface engineering strategy for scale, it is particularly important to understand the effect of some parameters in reducing scaling such as: surface parameters (e.g. the roughness (Keysar et al 1994;Cheong, Gaskell and Neville 2013;Liu et al 2011) and the wettability (Cheong, Gaskell and Neville 2013;Zhao et al 2005;Bargir et al 2009;Förster and Bohnet 1999;Azimi et al 2014;Herz, Malayeri and Müller-Steinhagen 2008a;Rankin and Adamson 1973a)), kinetics of crystallization and surface deposition (Crabtree et al 1999;Kitamura 2002;Yu et al 2004;Dyer and Graham 2002;Peyvandi, Haghtalab and Omidkhah 2012), and the induction time (Geddert, Augustin and Scholl 2011;Geddert et al 2009;Jaouhari et al 2000;Gabrielli et al 2003) for surface scaling which is dependent on the flow regime (Han et al 2006;Alahmad 2008;Vazirian and Neville) and the saturation rate (Merdhah and Yassin 2009). …”

An Integrated Fouling Monitoring Technique for a Water Treatment Microfiltration Process

“…8 demonstrates that the operation was stable after 1 h, as indicated by the almost constant MFI index value. The MFI index can also be used to monitor particulate fouling in water treatments and serve as a predictor for the fouling potential of feed water containing particles [30].…”