Application of seeded batch crystallization methods for reduction of the scaling tendency of seawater – A study of growth kinetics of calcium carbonate in seawater

Abstract

The objective of this study is to evaluate the applicability of a seeded batch crystallization method as a pretreatment stage to the reduction of the the scaling potential of seawater. The crystallization process of calcium carbonate in supersaturated seawater is studied experimentally in a seeded batch crystallizer. Results show that the initial pH value of seawater must be adjusted to be in the range of 8-9. Calcite seeds will not have the potential to start the growth process in seawater at he the normal pH (7.36) compared to the above mentioned range. The growth kinetic parameters are determined from the measured desupersaturation curves. It is found that the growth process of calcite is controlled by surface integration step. The growth rate of calcite increases with increasing temperature and seeding ratio (up to 1 g/L), while it decreases with increasing the salinity of seawater. Crystals of calcite morphology are found to be growing faster than seeds of aragonite morphology. Stirrer speed has no distinct effect on the growth rate of calcite in seawater.

The onset of spherulitic growth in crystallization of calcium carbonate

“…Thus to be able to calculate the supersaturation ratio with respect to aragonite, calcite supersaturation values were recalculated using Eqs. (4)(5)(6).…”

“…The inorganic calcium carbonate is also important for the immobilization of CO 2 with respect to the global carbon cycle [4]. However, the precipitation of calcium carbonate is often unwanted as it is one of the most important scaling agent [5,6] as, for example, in heat exchangers [7] as well as in oil and gas production where calcium carbonate scales decrease the production efficiency [8].…”

Electrochemical carbon dioxide capture to close the carbon cycle

“…In order to improve the kinetics of the precipitation, use of a seeded crystallizer unit is suggested [107,118].…”

Aragonite Kinetics in Dilute Solutions

“…More pragmatic concerns include controlling carbonate precipitation during desalinization (Elliot 1969;Morse et al 1979;Omar et al 2009), geothermal energy production (Arnorsson 1979;Amjad 1987), and waste treatment (Reddy 1978). More recently, aragonite precipitation kinetics have been studied to estimate and manipulate the growth rate of biogenic skeletal tissues (e.g., otoliths: Romanek and Gauldie 1996; restorative and osseous surgeries: Oudadesse et al 2004) and to effectively control the growth forms of aragonite for coatings and fillers in various industrial applications Deng 2003, 2004).…”