This paper focuses on the complex problem of calcium carbonate scale formation on heated surfaces and the possibilities of controlling or reducing this problem. The development of scale is a multistage process and is affected by a number of factors, these include supersaturation, pH, temperature and flow velocity. Calcium carbonate deposition can be ameliorated by chemical, physical or biological methods with various level of effectiveness. These controls can be divided into three main categories: those that affect solubility, those that alter the growth mechanism of crystals, and those that change the potential of a surface to foul. One of the most effective methods of controlling crystallization fouling is the addition of chemical inhibitors to potentially scaling waters. There are a number of alternative non-chemical treatment options available, amongst these are the use of magnetic, electronic and electrolytic treatment devices. Scale formation is affected by the physical nature of the material on which it is forming, therefore it is possible to choose material to reduce scale formation. Each of these scale controlling methods has their advantages and a number of factors have to be considered before choosing the right option.

Calcium carbonate scale formation and control

This study presents the advances in plate heat exchangers both in theory and application. It dresses the direction of various technical research and developments in the field of energy handling and conservation. The selected areas of heat transfer performance and pressure drop characteristics, general models and calculations change of phase; boiling and condensation, fouling and corrosion, and welded type plate heat exchangers and finally other related areas are highlighted.

Plate heat exchangers: Recent advances

Use of extended Kalman filtering in detecting fouling in heat exchangers

Calcium carbonate scaling in a plate heat exchanger in the presence of particles

Recent advancements in impedance of fouling resistance and particulate depositions in heat exchangers

This article describes particulate fouling experiments performed on small-scale and full-scale plate heat exchangers for three different corrugation angles (30 deg, 45 deg and 60 deg). The velocity effect has been studied as well as the particle type and concentration effects. The test duration ranges between 20 and 1,500 h in order to reach asymptotic behavior. The results clearly indicate that the corrugation angle has a major influence on the asymptotic fouling resistance. Increasing the corrugation angle leads to lower values for the fouling resistance. Furthermore, for a given corrugation angle, the asymptotic fouling resistance is inversely proportional to the velocity squared. Finally, the asymptotic fouling resistance is proportional to the particle concentration. Fouling mitigation can be obtained by taking into account at the design stage the heat exchanger geometry and fluid velocity.

S. Grandgeorge

Papers

Effect of Geometry and Flow Conditions on Particulate Fouling in Plate Heat Exchangers

Particulate fouling of corrugated plate heat exchangers. Global kinetic and equilibrium studies