Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
STUDY OF CALCIUM CARBONATE DEPOSITION INSIDE A PLATE HEAT EXCHANGER
Submission Author:
Karolyna Gomes dos Santos , RJ , Brazil
Co-Authors:
Karolyna Gomes dos Santos, Jean Izidoro da Silva, Gabriel Siqueira Machado, Juliana Ferreira Gonçalves, Juliana Loureiro
Presenter: Karolyna Gomes dos Santos
doi://10.26678/ABCM.COBEM2023.COB2023-1751
Abstract
Scaling is a phenomenon that occurs in heat exchangers used in different industrial applications. The fouling leads to loss of heat transfer efficiency and it requires either a chemical of mechanical resource for its removal. The aim of this study is to investigate the amount of calcium carbonate deposited in a plate heat exchanger. Results are provided the temperature variation between the two fluids (hot and cold); the dominant mechanisms for the formation of the scaling and characterization of the crystalline structure of the deposits. The experimental campaign was performed in a model M3-FG heat exchanger containing 27 plates with countercurrent flow. In order to form the calcium carbonate solution (cold fluid), two salt solutions were prepared: calcium chloride (CaCl2) and sodium bicarbonate (NaHCO3) in separate tanks with 5000 liters. After stabilization of pH of both solutions, they are pumped to a mixing point so that they can enter the heat exchanger. The hot fluid used was water at 80ºC from an 8000 liters tank heated by resistances. During the experiments, the following parameters were varied: duration of the experiment, flow rate, concentration of the salt solutions. Measured pressure drop, temperature variation between the fluids, overall heat transfer coefficient and scaling resistance are discussed for the different conditions. The scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses show the presence of aragonite and calcite, respectively, in the entrance and exit regions of the plates, where the cold fluid circulated. Results show that the deposition rate is non-linear, due to a complex interaction between the ionic/particle deposition and removal due to the shear flow.
Keywords
Plates Heat Exchangers, incrustation, Heat transfer, Deposition Rate
