Experimental study of an innovative wet scrubber concept in regards to particle filtration and pressure loss

The risen awareness of improved indoor air quality has resulted in an increased energy demand for HVAC systems due to higher air exchange rates and the additional operation of air purifiers. Therefore, the need for energy-efficient methods to improve indoor air quality has grown. In this experimental study, we develop an innovative wet scrubber concept to remove solid particles from the airflow. In contrast to conventional wet scrubbers, this concept uses a perforated plate and the hydrostatic pressure to feed water droplets into the air stream. The absence of injectors reduces the energy demand compared to common wet scrubbers, as the required pressure to generate the water droplets is significantly lower. In addition, the larger droplet sizes enable the usage of a matching droplet separator with negligible pressure drop. Within the scope of this work, we investigate the particle removal efficiency and the pressure drop for a range of ambient conditions, which represent the different seasons: summer, winter and transition period. Furthermore, we analyze three different volume flow rates of water to cover a broad spectrum of droplet formation regimes. In the scenarios investigated, we measure a pressure drop of 4 – 7 Pa and a particle removal efficiency of up to 38 %. The results show that the ambient conditions have little influence on the particle removal efficiency. However, the presented wet scrubber concept displays the same behavior as common wet scrubbers, where the particle removal is less efficient for smaller particles. The investigated wet scrubber concept demonstrates a significant decrease in particle removal efficiency for droplets with a diameter below 4 μm. Higher water flow rates improve the particle removal efficiency but also increase the pressure drop across the wet scrubber.