Cenosphere Separation from Fly Ash Using Modified Gravity Separator: Feed Ratio Assessment and Stream Velocity Optimization

Abstract

The increase of the population causing increased energy needs, one of which is electricity. Coal constitutes one of the largest carbon sources to generate electricity where the combustion leaves a by-product in the form of fly ash. Inside the fly ash, there are round- shaped hollow particles whose its density is lower than water of about 0.9 g/cm³. These particles called cenosphere containing alumino-silicate. Due to its lighter and tougher nature, it makes the cenosphere appealing to use as a lightweight and robust material. Cenosphere can be separated using both dry separation and wet separation. Separation using the wet process produces another impact on the side of the liquid media processing that is used because it potentially carries toxic compounds inside the fly ash. While the separation using the dry separation method still has problems regarding its efficiency. Modified Gravity Separator is a new design for cenosphere separation using air as a fluid medium. This research was conducted to evaluate the performance of the proposed geometry by looking at the effect of the feed velocity to the geometry expansion space using a CFD (Computational Fluid Dynamic) computing software. The feed particles are assumed to be spherical shape and are observed with the Euler-Lagrange equation where the particles interact with continuous airflow. The simulations were carried out at speeds of 0.1 m/s, 0.25 m/s, 0.5 m/s, and 1 m/s. This simulation successfully illustrates the flow pattern and predicts the recovery rate of each collector so that it can be evaluated and optimized for future investigation.