Foaming in Wet Flue Gas Desulfurization Plants:  The Influence of Particles, Electrolytes, and Buffers

Abstract

The objective of this work is to study the influence of particles, electrolytes, and buffers on the foaming ability of wet flue gas desulfurization (FGD) slurries. Foaming within this industrial process has been associated with a range of operational problems, as well as an increased degree of absorption. The foaminess of selected process parameters has been assessed, systematically, using laboratory-scale Bikerman experiments. Adipic acid alone, as well as a combination of small particles and an electrolyte, have been demonstrated to generate weak transient foams (with a Bikerman coefficient (Σ) of e7 s), that potentially can interfere with process monitoring equipment. Additional experiments with a wet FGD pilot plant showed an increased absorption efficiency of sulfur dioxide (SO 2 ) by a tap water solution with small quartz particles and calcium chloride (CaCl 2 ), compared to a solution of pure tap water.

π-Hole interaction: a theoretical insight into the mechanism of SO2 captured by [Et2NEMim][Tetz] ionic liquids

“…Therefore, nearly 5 mol SO2 mol IL −1 can be absorbed as a result of multiple-site interactions between the electronegative nitrogen atoms and the sulfur atom with positive charge in the acidic SO 2 . Note that Wang et al [19] reported a novel strategy for SO 2 . Compared with the interaction energies reported in [19], our results are relatively lower, which could be attributed to differences in the simulation model (in Wang et al [19], only the anion was considered, while in the present work the whole IL was included).…”

“…The second one is a π-hole interaction through the S atom in SO 2 as an electron acceptor and N atom in [Et 2 NEMim][Tetz] as an electron donor [32]. In the IL-1SO 2 complex, the S atom in SO 2 bonded to the N2 in [Tetz] − forms a π-hole interaction, while the two O atoms in SO 2 2.339 Å and 2.595 Å for N3⋯H2, O1⋯H5 and O3⋯H3, respectively. The fourth SO 2 has a larger effect on the first SO 2 and a smaller effect on the second and third SO 2 .…”

“…This positive region can attract the electron of the N atoms in [Et 2 NEMim][Tetz] and form a so-called π-hole interaction complex. It is necessary to study the π-hole interaction and hydrogen bonding because these interactions are crucial to the reaction of SO 2 and SO 2 were optomized and the most stable was chosen to form a 1:2 complex; (3) the same method was used to obtain the most stable 1:3-1:5 complexes. To examine the interaction characteristics of the complexes, the following points were investigated: (1) the interaction energy of each complex and the energy differences between the 1: n complex and 1: (n − 1) complex were calculated, and the ability of the [Et 2 NEMim][Tetz] to continually capture SO 2 in different positions was scrutinized; (2) the interaction bond characteristic of the complex were analyzed with a view to finding the difference between the hydrogen bond and π-hole interaction (formed by S and N atoms); (3) the strength of the interaction bond was studied using the natural bond orbital (NBO) methods; (4) the vibrational frequencies of the 1: n complexes were calculated and the intramolecular frequencies and their shifts due to the complex formation were analyzed; (5) the dependence of Gibbs energy changes (ΔG°s) on the temperature, pressure and the number of SO 2 absorbed by [Et 2 NEMim][Tetz] were analyzed, and the most suitable reaction conditions were found.…”

“…Thus, finding an effective method to reduce significantly the S-content in fuel oils is very important. In recent years, a number of technologies for flue gases desulfurization (FGD) have been developed, including wet or dry FGD processes [2][3][4][5][6]. Unfortunately, those methods have some obvious disadvantages, such as the production of a large amount of gypsum waste and waste water.…”

Absorption of Sulfur Dioxide in Ionic Liquid Supported on Porous Silica Particles

“…[1][2][3][4][5][6] Ionic liquids were found to be key absorbents, due to negligible volatility, high thermal and chemical stability, and tunable chemical properties, which have been widely used in gas separation. For instance, Han et al [7] first synthesized a base-functionalized IL, 1, 1, 3, 3-tetramethylguanidinium lactate (TMGL), and reported that it can effectively absorb SO2 from a simulated flue gas with high absorption capacity (0.978 mol SO2/mol TMGL) and high selectivity.…”