Pilot plant experiments and modeling of CaCO3 growth inhibition by the use of antiscalant polymers in recirculating cooling circuits

Abstract

New experimental data of antiscalant polymer efficiency are presented.• Industrial pilot plants are used using natural raw water.• We present, validate and discuss a model for polymer efficiency.• We provide insights on scale mitigation in recirculating cooling circuits. a b s t r a c tRecirculating cooling circuits are prone to the deposition of scale on heat exchangers and packing surfaces. The addition of antiscalant polymers is efficient for inhibiting the precipitation of calcium carbonate (CaCO 3 ) because polymers block the active growth sites. In this study, growth inhibition of calcite by using such polymers in industrial pilot plants operating with natural river water, which is critical to mimic a full-scale cooling circuit and accurately evaluate scale inhibition, was reported. Efficiencies of three commercial polymers were compared. The polymers thus investigated demonstrated comparable efficiencies and similar responses to changes in operating conditions. An adsorption-based model was proposed to quantify the inhibition of precipitation kinetics with respect to the process operating conditions and water qualities. Then, the model was validated at a wide range of polymer concentrations, temperatures, and water qualities, representative of industrial systems. A small amount of polymer was sufficient to affect bulk-scale prevention, albeit the efficiency became constant at high polymer concentrations. Under these conditions, a complementary treatment such as acid injection is necessary.

An azobenzene-based photoswitchable crystal growth modifier

“…Calcium carbonate was chosen as an ideal model system for crystal growth studies due to its relevance in industrial scale 29,30 and biological systems. 2,31 The most thermodynamically stable polymorph of CaCO 3 is calcite, the growth of which is known to be influenced by additives containing carboxylic acid functional groups.…”

“…2,31 The most thermodynamically stable polymorph of CaCO 3 is calcite, the growth of which is known to be influenced by additives containing carboxylic acid functional groups. 1,6,9,24,25,30 Thus attention was focused on the synthesis of carboxylic acid functionalised azobenzenes as target compounds for light modulated crystal growth additives. Particular attention was paid to the synthesis of the aspartic acid functionalised azobenzene 1 (Fig.…”

Research on performance optimization and mechanism of electrochemical water softening applied by pulse power supply

“…A variety of water treatment technologies are applied to soften the circulating water, such as the addition of acidic detergents and other chemicals, (Neveux et al 2016) exchange resins, reverse osmosis, nanofiltration and electrodialysis etc. (Almarzooqi et al 2014;Zhi & Zhang 2014).…”

Performance of green antiscalants and their mixtures in controlled calcium carbonate precipitation conditions reproducing industrial cooling circuits

“…They can lead to layers of hard scale, increasing heat transfer resistance and thus impairing heat exchange. This is a serious problem in industry, especially in high energy consumption equipment such as thermal and nuclear power plant cooling systems ( Neveux et al, 2016 ;Rahmani et al, 2015 ), reverse osmosis membrane desalination ( Al-Hamzah and Fellows, 2015 ;Phuntsho et al, 2014 ), distillation ( Al-Rawajfeh, 2008 ;Ghani and Al-Deffeeri, 2010 ) and petroleum production ( Heming et al, 2015 ). In electric power plant cooling systems, CaCO 3 precipitation and/or deposition depends on various factors such as circuit operating conditions (temperature range, concentration factor, water residence time) and circulating water quality (notably, concentrations of calcium and bicarbonate and of suspended matter) ( Chhim et al, 2017 ).…”