Review Article - Journal of Chemical Technology and Applications (2021) Volume 4, Issue 3
foaming in gas sweetening process: Comprehensive experimental efforts lead to better understanding and predication of amine foaming
In order to explore the foaming behaviour of aqueous Methyldiethanolamine (MDEA) in the presence of twenty distinct contaminants, including breakdown products, extensive experimental work was carried out. N,N,N-tris-(hydroxyethyl) ethylenediamine (THEED), hydroxyethyl ethylenediamine (HEED), N,N/-bis-(hydroxyethyl) piperazine (bHEP), N,Nbis-(2-hydroxyethyl) glycine (bicine), organic acids, and liquid organics are all examples of N,N,N-tris-(hydroxyethyl) ethylene. To further understand foaming behaviour, this foaming investigation was paired with physical characterisation of the studied solution. In terms of foam volume, the foaming propensity of aqueous MDEA solution was observed. The time it took for the final bubble to burst was used to determine foam stability. The findings of this investigation revealed that each contaminant altered foaming behaviour by altering foam volume, breaking time, or both. However, whatever contaminants are added to the amine solution, the physical characteristics of the amine are dragged to a point where the foaming behaviour is altered. The addition of THEED and HEED, for example, enhanced the foam propensity and stability of the solution by raising the solution viscosity; higher bulk viscosity prevents foam collapse induced by gravity drainage. Predicting and monitoring the physical characteristics behaviour and interaction is thought to be the bottleneck in predicting the foam behaviour of any solution. We're now striving to better understand the interaction between physical characteristics and their combined influence on the amine solution's foaming behaviour, which will lead to a breakthrough in foaming monitoring and prediction. This research presents mathematical models of foaming propensity and stability to explain the influence of physical variables on foam volume and breaking time of aqueous MDEA solutions. Amine systems that use alkanolamines for acid gas absorption such as methyldiethanolamine (MDEA) have a constant challenge in terms of sustaining and growing process throughput and profit. Contaminants such as heat stable salts (HSS) and heavy metal ions, on the other hand, obstruct smooth operation and create system downtime and upsets. These HSS are produced by the reaction of MDEA with acid gases (H2S and CO2), followed by the reaction of the protonated MDEA (MDEAH+) with strong acid anionic species such as formate, acetate, propionate, thiosulfate, and others, and cannot be regenerated by heat. The presence of HSS in the amine degrades the solvent quality, diminishes H2S absorption capacity, and increases foaming, resulting in considerable MDEA loss. Fouling of the equipment, on the other hand, is caused by metal impurities in the makeup water or by corrosion or erosion induced by the plant's continual operation. As a result, amine reclamation, which reduces these contaminants to lower levels, has become a vital step for the gas sector to take in order to improve operations considerably. Few attempts to remove HSS breakdown products and heavy metal ions from contaminated amine solutions using neutralisation, vacuum distillation, electro dialysis, ion-exchange, and adsorption have been documented in the literature. Solid sorbent adsorption has attracted a lot of attention because of its high removal effectiveness, capacity to remove even residues of pollutants, and inexpensive operating, installation, and regeneration costs.
Author(s): Emad Alhseinat and Fawzi Banat