Semi-mechanistic modelling of ammonia absorption in an acid spray wet scrubber based on mass balance

Ethanol Recovery from Stripping Gas Mixtures by Gas Absorption: Experimental and Modeling

“…Mass transfer data for ethanol and water absorption are scarce in the literature. However, there are studies that have evaluated other operating conditions (different solutes, solvents, contactors, or liquid and gas flow rates), obtaining coefficients on the same order of magnitude as the K y a E and K y a W values found here, which supports the results obtained in the present study. ,,, …”

“…This could also explain the differences between the values for the first and second absorbers in assays A10, A11, and A12 (see Figures c and c). In previous absorption studies using a packed tower and a wet spray scrubber, it was shown that the mass transfer coefficient, based on the gas film, varied with the solute concentration in the gas phase. This phenomenon was attributed to the changes in surface tension, rather than dependence of the mass transfer coefficient on the solute concentration .…”

“…The second term on the right side of eqs and is based on the two-film theory of gas absorption that describes the mass transfer of a solute from the gas to the liquid phase. , The absorption rate is conveniently described in terms of an overall coefficient based on either the gas film ( K y ) or the liquid film ( K x ), which can be related to the individual film coefficients ( k y and k x ) . The relationship between K y and the coefficients k y and k x is given as follows where H xy is the effective Henry’s law constant, in mole fraction units (mol mol –1 ).…”

“…Note that in the modeling procedure, the absorption rate was described in terms of the overall volumetric mass transfer coefficient ( K y a ), incorporating to K y the interfacial area ( a ) per unit volume. The gas film was adopted as a reference because the solutes (water and ethanol) have very high solubility in the solvent (MEG). , The values of ṁ E4 and ṁ W4 , which represent the mass flow rates of ethanol and water entering the absorber as condensed liquid, were calculated using eqs and . The values of y EA * and y WA * were determined using eqs and , which describe the gas–liquid equilibrium for the system consisting of ethanol, water, MEG, and CO 2 , using the γ–φ approximation and considering that CO 2 is insoluble. where γ EA and γ WA are the activity coefficients for ethanol (E) and water (W) in the first absorber liquid phase, respectively, and x EA and x WA are the molar fractions of ethanol and water in the liquid phase of the first absorber, respectively.…”

Mesoscale behavior study of collector aggregations in a wet dust scrubber

“…However, their fine-dust removal efficiency is relatively low, amounting to 50.3% for dust particles of 0.5 μm in size (Ma and Jia, 2007), as compared with that of 62.48% for 0.25-μm-sized particles provided by a turbulent wet scrubber with a feed rate of 140 mg/min in a gas flow of 3.5 m 3 /min and a water level of 58 cm (Byeon et al, 2012). Currently, the studies of selfexcited dust scrubbers are mainly focused on the dust removal efficiency, pressure drop characteristics, dust removal liquid additives (modification of surface structure of dust removal liquid molecules), and two-phase flow patterns (Dullien and Munro, 1973;Li et al, 2016b;Hadlocon et al, 2015;Khan et al, 2016;Mueller et al, 2015), addressing either macroscopic (dust scrubber) or microscopic (dust removal liquid molecules) levels with no account of the interface phenomena occurring in between these levels. This gap was filled with the development of mesoscale approach (Charpentier, 2002;Fiore et al, 2015;Ge et al, 2011;Shaffer et al, 2013;Li et al, 2010), the application of which to self-excited dust scrubbers is expected to yield more insight into their dust removal mechanism and theoretically substantiate the required technological innovations for improving the dust removal efficiency.…”