Influence of wall atomizer to condensation rate in flashing purification

Abstract

This paper presents an experimental study of wall atomizer usage in flashing purification. The water jet bursts out of the nozzle and hit the wall atomizer, splits into particles and evaporates until it finally condenses. The effectiveness of water particle evaporation influences the condensate volume. In this paper, improvements were more focused on how to generate water particles by applying a wall atomizer in a flashing chamber. The more water particles were created, the better the evaporation and condensation rate. Flashing purification experiments were conducted by following the factorial design method. From the first experiment design, an optimum condensate volume was obtained at a specified folding width of wall atomizer and feedwater pressure; meanwhile, vacuum pressure and feedwater temperature were kept constant. Three different folding widths of 5mm, 8mm and 12mm were tested in this experiment. The second experiments were continued by varying feedwater temperature at an optimum atomizer folding width to obtain more condensate volume. Wall atomizer usage in flashing purification has been proved to increase condensation rate or condensate volume. The highest condensate volume of 150.2ml was obtained from 8mm atomizer folding width with a variable combination of 2.0 bar-g feedwater pressure, a vacuum pressure of −53 cmHg and feedwater temperature of 70 °C. This result was in line with the theory that states that the presence of a wall atomizer increases water particles. There was even an atomizer folding width that provided an optimum condensate volume. The use of an atomizer folding width of less and more than 8mm produced lower condensate volume. At 5mm atomizer folding width, condensate volumes were 24.6ml and 22.0ml, whereas 12mm atomizer folding width produced 48.9ml and 50.3ml.

Numerical Simulation of Flashing Flows in a Converging–Diverging Nozzle with Interfacial Area Transport Equation

“…Flashing occurs when the pressure of a liquid rapidly decreases below the saturation pressure at a given temperature [1]. Flashing flow has been widely used in industrial production and can be divided into three categories based on the corresponding technical principles: (1) separating liquid phase and heterogeneous substances, such as multi-stage flashing technology for seawater desalination [2]; (2) flashing spray technology to improve spray performance, e.g., cooling high-power equipment or improving fuel combustion characteristics [3]; and (3) converting thermal energy to other forms of energy, such as using steam from flashing to drive steam turbines to generate electricity in geothermal power plants [4].…”