Clyde Bergemann Materials Handling: Solutions

Historically, the method adopted to convey fly ash is known a Lean Phase conveying. This uses high volumes of low-pressure compressed air to entrain the material in a high velocity stream of air (>30m/s). Due to these high velocities the wear on the system is very high, it also requires a considerable amount of energy to create the large volumes of conveying air.
An alternative to Lean Phase conveying is Medium Phase conveying. This method conveys material at slower velocities (10-15 m/s), with the majority of the material being conveyed on the bottom of the pipe. This type of system is best suited to difficult materials to handle such as Bed Ash and Crushed Limestone.
The type of technology preferred by Power Plants throughout the world is Dense Phase Conveying. This uses much smaller volumes of air at higher conveying pressure (typically 1.5 BarG) and slower velocities (2-8 m/s) to convey the material in a solid plug form, thereby reducing the wear on the system and also substantially reducing the energy consumption required to generate the conveying air.