Highly accelerated sedimentation of flocculated micron-sized particles using a high-speed separator

There exist several types of water cleaning systems for the cleaning the scrubber washwater, where each type has its benefits and disadvantages. The two most common types of water cleaning systems utilise either a high-speed separator or a membrane. This project will focus on the water cleaning system including a high-speed separator, since they are generally cheaper and more easily maintenance onboard a vessel.
There exists a large variety of HSSs depending on the application, feed, surroundings etc. The HSS used for the marine scrubber water cleaning system is a disc-stack separator where the fluid enters and exits at the top of the separator. The advantage with this type of HSS is that it is a very reliable machine that requires a minimum of maintenance. The downside is that the feed is subject to a high shear rate at the inlet of the HSS, as shown in Fig. 1. The flow enters a hollow cone and is ‘hurled’ to the circumference of the inlet cylinder. From here the flow is directed into the disc stack where the phases are separated due the density difference. The settling velocity is a function of the particle size and if the particles break-up at the inlet of the HSS, the separation efficiency of the HSS is decreased. To separate a sufficient amount of PM, the feed must be optimised for these high-shear conditions.