Analysis Of Temperature Effect on Struvite Scales Controlling in A Vertical Reactor

Abstract

Scale is forming and controlling in industrial applications causes the clogs or decreasing in volume flows in the pipes, so increasing maintenance cost can occur as a consequence. Struvite discovered as Magnesium Ammonium Phosphate Hexahydrate (MgNH4PO4.6H2O) and referred as a scale due to the heating process of fluid through pipes. The aim of this research was investigated the temperature effect on process of scales forming and controlling. The process was used a vertical bulkhead reactor. The process starts from mixing the equimolar solutions of MgCl2, NH4OH, H3PO4 with 1: 1: 1 of ratio concentration. Then, crystallization process was carried out with the condition at the variation of temperature (20-40°C), variation of pH value (pH 8-10) and variation of air inlet rate (0.25; 0.50; 0.75; 1.0; 1.25 L/min) while the feed rate was 25 ml/min. The process continues until the condition becomes steady state. The scale controlling process was determined by the presence of struvite deposits. The deposits were analyzed by using the XRF method to determine composition content. The optimal conditions were obtained at a temperature of 30°C, pH 9, and air rate of 1.25L/min.

Recovery of High Concentrations of Phosphorus and Ammonium through Struvite Crystallization by CO2 Repelling

“…It was shown that the struvite solubility was the lowest and the rate of struvite crystallization was the highest for pH values in the range 8.5–9. [ 10,20–22 ] At a constant pH, the supersaturation increased with the phosphorus concentration and the highest supersaturation values were obtained for a pH equal to 9. [ 23 ] However, as far as the authors are aware, no studies on how high concentrations of phosphorus and ammonium affect the precipitation pH of struvite were reported in the literature.…”