Computational fluid dynamics comparison of prevalent liquid absorbents for the separation of SO2 acidic pollutant inside a membrane contactor

Abstract

In recent years, the emission of detrimental acidic pollutants to the atmosphere has raised the concerns of scientists. Sulphur dioxide (SO2) is a harmful greenhouse gas, which its abnormal release to the atmosphere may cause far-ranging environmental and health effects like acid rain and respiratory problems. Therefore, finding promising techniques to alleviate the emission of this greenhouse gas may be of great urgency towards environmental protection. This paper aims to evaluate the potential of three novel absorbents (seawater (H2O), dimethyl aniline (DMA) and sodium hydroxide (NaOH) to separate SO2 acidic pollutant from SO2/air gaseous stream inside the hollow fiber membrane contactor (HFMC). To reach this goal, a CFD-based simulation was developed to predict the results. Also, a mathematical model was applied to theoretically evaluate the transport equations in different compartments of contactor. Comparison of the results has implied seawater is the most efficient liquid absorbent for separating SO2. After seawater, NaOH and DMA are placed at the second and third rank (99.36% separation using seawater > 62% separation using NaOH > 55% separation using DMA). Additionally, the influence of operational parameters (i.e., gas and liquid flow rates) and also membrane/module parameters (i.e., length of membrane module, hollow fibers’ number and porosity) on the SO2 separation percentage is investigated as another highlight of this paper.

Development and evaluation of a hollow fiber membrane contactor for carbon dioxide capture

“…Making selections about material selection, figuring out the ideal membrane thickness, and learning more about the system's flow dynamics are all made easier with its help. This information is crucial for enhancing the performance and efficiency of the membrane contactor, which eventually results in improved CO2 capture and separation procedures 27 . Figure 9 shows how changing the gas feed rate affects the amount of CO2 removed while keeping the liquid feed rate constant at 10 ml/min.…”

Modelling and dynamic simulation to produce fermentable sugars from lignocellulosic substrates through dilute acid hydrolysis

“…Throughout the acid hydrolysis, the batch reactor is host to an array of chemical reactions, stemming from the solubilization of hemicellulose, lignin, and cellulose. [21,23] The mechanisms governing certain irreversible reactions within the hydrolysis process are expounded below:…”

“…Nonetheless, a notable drawback associated with commercial simulators lies in their inherent limitations, as they rely on the availability of kinetic models for various lignocellulosic compounds within their databases. For instance, Cao et al [ 21 ] employed the ASPEN Plus simulator to simulate equilibrium reaction models for the pyrolysis stage of biomass. However, discrepancies emerged in the fitting of pyrolysis reactants and resulting products into the ASPEN models.…”

“…Throughout the acid hydrolysis, the batch reactor is host to an array of chemical reactions, stemming from the solubilization of hemicellulose, lignin, and cellulose. [ 21,23 ] The mechanisms governing certain irreversible reactions within the hydrolysis process are expounded below: …”