Experimental Studies on Effect of Neighboring Droplets on Evaporation of Aqueous Ammonia and Monoethanolamine (MEA) Droplets

článek ve sborníku mimo WoS a Scopus

en

The spraying of chemicals such as Monoethanolamine (MEA) and aqueous Ammonia (75% Water + 25% Ammonia) is widely used in spray columns for CO2 removal from the exhaust and process gases. When the droplets in the spray interact with the flue gas, due to temperature difference, along with the absorption of CO2 from the flue gas they undergo evaporation as well. Changes in the diameter as the droplet evaporates will change the surface area and gas concentration inside the droplets, influencing the rate of absorption of CO2 into the droplet. Understanding the droplet evaporation and the influence of the surrounding droplets on the evaporation of droplets is one of the important aspects to address for developing reliable models for CO2capture from flue gasses. This work focuses on studying single droplet as well as simultaneous evaporation of multiple droplets of MEA and aqueous Ammonia. The droplets suspended on a microfiber grid made up of 100 μm glass fiber is introduced into the heating chamber and the evolution of the droplet size is recorded using backlight imaging. Images are processed using Matlab algorithms to obtain the droplets’ evaporation rate. The presence of droplets in the neighborhood reduces the evaporation due to change in the ambient concentration of vapor. When the spacing between the droplets is larger, i.e. 5 mm (5 times the droplet diameter) in this case, increasing the number of droplets around the primary droplet has no significant effect on the rate of evaporation. However, the effect is pronounced when the spacing between the droplets is reduced to 2.5 mm (2.5 times the droplet diameter). Findings of these experimental results can be used in designing the atomizers for the removal of CO2 from the flue gases.

The spraying of chemicals such as Monoethanolamine (MEA) and aqueous Ammonia (75% Water + 25% Ammonia) is widely used in spray columns for CO2 removal from the exhaust and process gases. When the droplets in the spray interact with the flue gas, due to temperature difference, along with the absorption of CO2 from the flue gas they undergo evaporation as well. Changes in the diameter as the droplet evaporates will change the surface area and gas concentration inside the droplets, influencing the rate of absorption of CO2 into the droplet. Understanding the droplet evaporation and the influence of the surrounding droplets on the evaporation of droplets is one of the important aspects to address for developing reliable models for CO2capture from flue gasses. This work focuses on studying single droplet as well as simultaneous evaporation of multiple droplets of MEA and aqueous Ammonia. The droplets suspended on a microfiber grid made up of 100 μm glass fiber is introduced into the heating chamber and the evolution of the droplet size is recorded using backlight imaging. Images are processed using Matlab algorithms to obtain the droplets’ evaporation rate. The presence of droplets in the neighborhood reduces the evaporation due to change in the ambient concentration of vapor. When the spacing between the droplets is larger, i.e. 5 mm (5 times the droplet diameter) in this case, increasing the number of droplets around the primary droplet has no significant effect on the rate of evaporation. However, the effect is pronounced when the spacing between the droplets is reduced to 2.5 mm (2.5 times the droplet diameter). Findings of these experimental results can be used in designing the atomizers for the removal of CO2 from the flue gases.

Neighboring Droplets, Evaporation, Aqueous Ammonia, Monoethanolamine

28.10.2022

671–676

6