Digital imaging measurement of dense multiphase flows in industrial processes

This paper presents a submersible imaging system for investigations of multiphase flows in various industrial applications. Our objective is to visualize and online monitor complex multiphase flows that take place in industrial process devices (e.g., reactors, channels and flotation tanks) of chemical and paper industries. The system presented, including a laptop computer, CCD camera and pulsed, optical fibre-coupled diode laser, is designed for industry-scale, in situ measurements of dispersed phase particle properties (size, shape and velocity). The system has been successfully tested in a waste water dissolved air flotation (DAF) tank, in a white water de-aeration channel, in a deinking flotation cell Metso OptiCell and in a plastic bead production reactor, where the hot and pressurized plastic bead production process is monitored through a submersed pipe. New image processing techniques and system modifications are presented based on the test experiences.