###### Abstract
Electrostatic Precipitators (ESPs) can remove suspended droplets from gas by charging the droplets in a corona discharge and separating them from the gas by means of an electric field [31]. On the other hand, spray condensers can be defined as contact condensers, and just like jet condensers, they make use of water or some other liquid in direct contact with the vapor to be condensed. When working with pyrolysis vapors, generally, a paraffinic oil or even the bio-product itself is circulated as quench fluid. Some of the advantages of direct-contact condensers are that they are usually simpler in design and less expensive than the surface type. They rely on the simultaneous transfer of heat and mass, therefore resulting in higher condensing effectiveness [32]. The appearance and composition of the resulting liquid pyrolysis products depend on the type of downstream staged fractionation adopted and the targeted liquid fraction. In addition to a staged approach to the pyrolysis processes in the primary reactor [33], a further upgrading of bio-oils to transport fuels and chemicals can be achieved by stage-wise fractional condensation. In general, bio-oils collected from first condensers, operating at higher temperatures, contain significantly less water and acetic acid and large amounts of sugars and products of lignin pyrolysis. These fractions are often referred to as feedstocks for transportation fuel and monosaccharide production. The later condensation stages are designed to recover most of the water-soluble compounds with lower molecular weight compounds, such as light oxygenated compounds (e.g., ketones, acids) [34]. Among the high value-added products derived from pyrolysis of biomass, it is worth also mentioning fertilizer applications meant to improve soil health and harvest yields. Just to cite a significant case, the pyroligneous acid, better known as wood vinegar (WV), has shown favorable properties as biochemical for agriculture [35]. Generally, fast pyrolysis oil obtained via processing of lignocellulosic biomass is very acidic in nature, and the major component responsible for this property is acetic acid, which is present at levels up to 2-10 wt.% [36] and responsible for FPBO low pH value (ca. 2-3). For the same reason (including the presence of light organics), aqueous phase products should be considered to be valuable and their further processing investigated within a biorefinery approach and circular economy perspectives [37]. Acetic acid is an important industrial commodity, with a worldwide production of over eight million tons per year [38]; its extraction shows some potential to significantly boost the economic attractiveness of the entire bio-oil production process. The most recent experimental investigations focused on separating groups of target compounds as bio-oil fractions. Condensation temperature ranges are determined based on dew points of specific organic groups, thus allowing for the selective and physical separation between each fraction [39]. Controlling nitrogen flow [40] and narrowing cooling temperatures [26] are key features for maximizing the recovery of liquids. At an industrial scale, the bio-oil itself is used as the condensing medium; however, due to the typical pilot-scale of the experiments available in the literature, generally, researchers used mineral oils as an indirect cooling medium to control the exit cooling temperature of vapors/aerosols [41; 42]. In general, these paraffinic liquids are employed in direct-spray contact condensers to better control the condensation temperature if compared to the solutions involving jacketed devices [26]. The quenching of volatiles in an almost immiscible hydrocarbon solvent eases the determination of mass balance and the compositional analysis of liquids also due to the well-known composition of the mineral oil, as demonstrated by [PERSON] et al. [39].