# Experimental and Numerical Investigation of Spray Scrubber Dust Collection Efficiency
## 1 Introduction  
Spray scrubbers are important elements in contamination removal industry widely used in order to remove pollution from gas streams. These devices use droplets of liquid introduced to the system through the nozzles. The main purpose of using spray scrubbers is to reduce environmental pollution by efficient decrease of concentration of potentially harmful substances like sulfur dioxide, nitrous oxide, and solid particles, which are generated during various industrial processes, including energy production, manufacturing of various items, and waste burning. Spray scrubbers allow to fulfill the demands of rigorous air quality standards introduced all over the world. Due to the reduction of contaminants in the exhaust gases, the negative impact of various industrial processes on environment is significantly decreased. In recent years, the optimization of spray scrubber efficiency in various applications is becoming more and more popular as a scientific research subject. A lot of experimental investigations concerning droplet size, spray density, nozzle geometry, droplet residence time, and its impact on gas cleaning efficiency have been performed. Below, some ofthe latest scientific publications are presented, with the scope connected to experimental investigation of spray scrubber efficiency. For most of these articles, the methodology, installation size, type of gas, and contamination were specified. The fundamental mechanism of gas cleaning in spray scrubbers involves the collision of solid particle and collector droplet generated in the nozzle. Such process was discussed in various scientific research papers [1; 2; 3; 4]. The contact time between liquid and gas phase significantly impacts the efficiency of gas absorption. The contact time can be controlled by gas-liquid mass transfer and mutual configurations of gas and liquid droplets velocity vectors. They can be situated countercurrent, cocurrent, or in the crossflow arrangement [4]. For most cases, spray scrubbers reach particle removal efficiency on a level around 90% for particle bigger than 5 \(\upmu\)m, 60 to 80% for particle size from three to five micrometers, and 40 to 50% for submicron particles [1]. There are several researches where the impact of droplet size on collection efficiency was investigated. [PERSON] [5] and [PERSON] [6] examined the influence of droplet diameter on the efficiency of CO\({}_{2}\) removing process. Moreover, [PERSON] [5], [PERSON] [7], and [PERSON] and [PERSON] [8] investigated the impact of spray nozzle quantity on gas cleaning performance. [PERSON] and [PERSON] [8] noticed that the efficiency of SO\({}_{2}\) removal decreases with the increase in nozzle diameter. They also observed that an increase in the velocity of droplet generated by the nozzle leads to particle removal efficiency enhancement. Moreover, the droplet distribution shape inside the scrubber chamber, which is affected by the nozzle layout, plays a significant role in gas cleaning efficiency. [PERSON] [7] highlighted the crucial role of operating pressure during cleaning process, while [PERSON] [9] indicated that during removing the smaller particles (size below 10 \(\upmu\)m), increasing the spray density is very efficient. Other researchers focused on the impact of the volumetric gas-liquid ratio on different heights of spray scrubber and its effect on the separation efficiency. [PERSON] and [PERSON] [10], [PERSON] [11], and [PERSON] [12] investigated how setting deflectors in different locations affects the removal efficiency and droplet distribution. [PERSON] [13] combined traditional physical-mathematical models with AI techniques to predict the performance of a marine SO\({}_{2}\) absorption scrubber. Data were gathered over a year from real-time monitoring of scrubber operations onboard a cargo ship. In this study, SO\({}_{2}\) was the primary contaminant, and seawater or NaOH solutions were used to scrub sulfur dioxide. The system achieved more than 97% SO\({}_{2}\) removal efficiency in Sulfur Emission Control Areas (SECA).