Waste incineration (WI) generates highly polluting gases requiring treatment technologies that ensure compliance with EU emission standards. With growing health and climate change concerns, limit values for particulate emissions from WI are expected to evolve to consider particle size. It is therefore crucial to ensure that fumes treatment facilities are equipped with air pollution control (APC) devices capable of capturing all particle size ranges. Simple wet scrubbers (SWS), a widely employed APC device, are not considered performant for collecting particles with a diameter of less than 1 µm. However, studies [1] have shown that by adjusting the scrubber operating conditions (e.g. droplet size, liquid to gas ratio), collection of submicron particles can be improved. Given the widespread use of these units and their potential for submicronic particle collection, it is crucial to study their behavior and optimize their performance. In this work, a downscaled wet scrubber was designed, built, and set-up in a municipal WI plant to be fed with real fumes and to study its efficiency regarding the removal of particulate matter contained in WI fumes.

The downscaled system was implemented at the municipal WI plant in Nantes (France), where domestic, medical, and industrial waste are incinerated, and which consists of a furnace, a heat recovery boiler, a cooling tower, a baghouse filter with sodium bicarbonate and lignite coke injections, and a selective catalytic NOx reduction system. The wet scrubber was installed after the cooling tower, where the fumes reach ...

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The particle size distribution (PSD) at the inlet (Cin) and outlet (Cout) of the scrubber was measured to quantify its performance under operating conditions presented in Table 1. Samples were taken with isokinetic nozzles located inside the scrubber, aligned with the gas flow, and properly isolated from the spray. The inlet sample was taken at a height of 2 m, in the center of the tower and the outlet sample was taken next to the scrubber gas outlet. Particle counting was performed by using an Electrical Low Pressure Impactor (ELPI, Dekati). Short (30 – 45 s) and sequential ...

The PSD at the inlet of the downscaled wet scrubber measured by the ELPI is presented in Figure 2. This distribution can be considered as the PSD in the main industrial duct, subject to losses in the scrubber inlet line. The modal diameter is 0.31 µm for a concentration between 7 and 9 x 10⁵ #.cm^-3. Figure 3 illustrates the collection efficiency of the downscaled wet scrubber as a function of the aerodynamic particle diameter, for the above-mentioned operating conditions. As the particle size decreases, the scrubbing efficiency also diminishes, reaching a minimum of 7% at 0.31 µm. Negative collection efficiencies (-12%) were obtained for ...