Numerical Simulation Study on Characteristics of Vertical Gravity Separator in a Kalina Cycle System

Abstract

In various novel thermodynamic cycles which utilize waste heat and geothermal resources, the Kalina cycle is the most significant improvement in thermal power plant design and it has been considered as an ambitious competitor against the Organic Rankine Cycle. However, the kalina cycle faces the complicated separate process and the design of separators still depends on the experience empirical formulae. Therefore, the vertical gravity separator used for separating ammonia-water mixture plays a vital important role in this system. The separator should keep high separation performance and enable the system to operate with stability. In this paper, we propose the initial structure design of a vertical gravity separator according to the separation theories. Based on the initial structure design of separator, conventional separator has been improved by changing the structure and operational parameters, including the ammonia concentration, inlet velocity, diameter, angle and height of inlet, and that has been numerically simulated by the means of CFX in computational fluid dynamics. In-depth estimating the separating performance of vertical gravity separator, different structural and operational parameters of vertical gravity separator are simulated and discussed. The separation performance and the distribution of ammonia-water mixture are estimated including flow field, trajectories of motion of particles, pressure drop, separation efficiency and so on. The results can be expected to be of great technical interest as basis for the design of vertical gravity separators.