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The marine exhaust gas containing SO2 leads to serious impacts on human health and marine environments. Due to the strict emission standard of marine exhaust gas and the limited space of ships, desulphurization process intensification is urgent. Herein, a cross‐flow rotating packed bed (CF‐RPB) with a compact size was developed toward desulphurization of marine exhaust gas. According to the emission standards of different sea areas, the characteristics of simulated open seawater desulphurization (OSD) and closed alkali desulphurization (CAD) were systematically evaluated. The respective correlations for Kya of OSD and CAD were proposed to predict the height of CF‐RPB. The desulphurization efficiencies of 86% in the OSD and 97% in the CAD were achieved in a three‐stage CF‐RPB, satisfying the emission standard. Compared with the traditional spray tower, the CF‐RPB has a higher mass transfer coefficient with a smaller volume, which has great potential for desulphurization of marine exhaust gas. [ABSTRACT FROM AUTHOR]

Abstract: An innovative technique to remove SO2 from flue gas, comprising a rotating packed bed (RPB) coupled with an electric‐field device, is presented herein. The effects of operating conditions, such as packing type, rotation speed, gas‐liquid volumetric ratio, Na2SO3 content, and voltage supply on SO2 removal efficiency (η), as well as the gas‐phase overall volumetric mass‐transfer coefficient (KGa), were systematically investigated. Results indicate that a high η can be achieved under certain operating conditions. A correlation to predict KGa was also established and results show that the predicted values are in agreement with the experimental results. This work generally provides a feasible means of intensification for flue gas desulfurization. [ABSTRACT FROM AUTHOR]

Absorption of SO2 from a gas mixture with an ammonia-based solution was investigated using a counter current rotating packed bed (RPB) with SiC structured packing and plastic packing. Effects of operating parameters, such as the rotational speed, liquid flow rate, gas flow rate, liquid-gas ratio, inlet concentration of SO2, and the alkalinity of absorbent on the removal efficiency of SO2, were examined. Experimental results showed that the plastic packing had a better desulfurization performance under the same operation conditions. Moreover, correlations of gas-side volumetric overall mass transfer coefficients of the RPB with the two types of packing were obtained and the predicted data were in good agreement with experimental results. [ABSTRACT FROM AUTHOR]

In this work, a desulfurization method using natural amino acid salts (AAS), which can be green prepared by biological fermentation, is proposed to remove H 2 S from raw biogas. Biogas purification and fertilizer production can be simultaneously achieved to close sulfur recycle. The reaction kinetic characteristics of H 2 S absorption with three kinds of AAS, including potassium β -alaninate (PA), potassium sarcosinate (PS) and potassium l -prolinate (PP) are first studied. Kinetic parameters including orders of reaction, rate constants, pre-exponential factors and activation energies are given. AAS absorbent exhibits good potential for biogas desulfurization. Higee (high gravity) technology is utilized to intensify H 2 S removal. The effects of operating conditions on H 2 S removal efficiency are investigated and PP shows the best desulfurization performance. The phytotoxicity of AAS and amino acid salt sulfide (AASS) is assessed by the germination index of mungbean seeds. PP and its salt sulfide (PPS) show relatively low phytotoxicity and their allowable agricultural feeding concentrations are below 0.08 M and 0.04 M, respectively. The desulfurization method demonstrates a green route for biogas purification to achieve sulfur recycle. [Display omitted] • A green route for biogas purification using natural amino acid salts. • The reaction kinetics of H 2 S and amino acid salts is given. • Desulfurization by amino acid salts is intensified by rotating packed bed. • Desulfurization product is used as fertilizer to achieve sulfur recycle. [ABSTRACT FROM AUTHOR]

[Display omitted] • Packings with different fiber cross-sectional shapes were designed and fabricated. • H 2 S removal with chelated iron solution was investigated in an RPB reactor. • V Q H E obtained higher H 2 S removal efficiency and mass transfer coefficient than V C H C. • V Q H E deposited less sulfur solid on surface than V C H C which alleviated blockage. HiGee reactors have been utilized for H 2 S removal from offshore natural gas by chelated iron solution, which exhibits great advantages due to their compact footprint. However, the blockage of packing in HiGee reactor caused by sulfur generation can lead to a decline of desulfurization efficiency. Herein, the fiber cross-sectional shape of mesh packing was optimized for alleviating blockage based on the understanding of liquid flow behavior with various single-layer meshes in our previous studies (Wen et al., Chem. Eng. Sci. 2022, 248, 117147). The novel packing with vertical quadrangular fibers and horizontal elliptical fibers (V Q H E) as well as the conventional packing with circular fibers (V C H C) were designed and fabricated by three-dimensional printing technology. A rotating packed bed (RPB) reactor with mesh packing, as one of the typical HiGee reactors, was adopted for H 2 S removal. Results indicate that H 2 S removal efficiency of V Q H E could reach up to 99.3%. The mass transfer coefficient of V Q H E was 25.9% higher than that of V C H C. Meanwhile, the photograph displays that less sulfur solid was deposited on the surface of V Q H E. The mass increase ratio of V Q H E was smaller by 24.9% than that of V C H C. V Q H E realized the integration of enhancing H 2 S removal efficiency and alleviating blockage in RPB reactor. [ABSTRACT FROM AUTHOR]

• The reaction kinetics of SO 2 and NaLa/water DES was firstly studied. • Desulfurization by NaLa/water DES was intensified by rotating packed bed (RPB). • A mathematic model was developed to describe the mass transfer process in RPB. • A satisfactory agreement was obtained between experimental and modeling results. As ionic liquids alternative, the deep eutectic solvents (DESs) are expected to realize green and efficient SO 2 recovery. In this work, the reaction kinetics of SO 2 and sodium lactate (NaLa)/water DES was first studied. The reaction kinetic parameters, including order of reaction, rate constant, pre-exponential factor, and activation energy were determined. In view of the reaction characteristics, desulfurization intensification by high gravity technology was proposed. A mathematic model based on the reaction kinetics was developed to describe the SO 2 -DES mass transfer and reaction process in a rotating packed bed reactor. To validate this model, the desulfurization efficiency and mass transfer coefficient were measured under different operating conditions. It was demonstrated that SO 2 removal efficiency was above 99% under optimized conditions, realizing efficient SO 2 recovery. The validity of the proposed model was confirmed by the fact that most predicted mass transfer coefficients agreed well with the experimental results with deviations within ± 15%. [ABSTRACT FROM AUTHOR]

• A mathematic model was first developed to describe mass transfer process in RPB. • The outlet SO 2 concentration was ultra-low, below 35 mg/m3. • The predicted desulfurization efficiency agreed well with the experimental result. • The HTU for RPB is one order of magnitude lower than that of conventional reactors. In order to reduce SO 2 emissions and achieve green utilization of sulfur resources, a desulfurization method of SO 2 removal using hydrogen peroxide (H 2 O 2) in rotating packed bed (RPB) is proposed. It can not only achieve the efficient removal of SO 2 , but also lead to the effective utilization of sulfur resources. A mathematic model was first developed to describe the reaction and mass transfer process between H 2 O 2 and SO 2 in RPB. The influences of different operating conditions including RPB rotating speed, H 2 O 2 mass fraction, gas–liquid volumetric flow rate ratio, gas flux, and inlet SO 2 concentration on desulfurization performance were studied. Under the optimized conditions, it turned out that the desulfurization efficiency was above 99% and the outlet SO 2 concentration was ultra-low, below 35 mg/m3. The validity of the model was confirmed by the fact that most of the predicted desulfurization efficiency agreed well with the experimental result with a deviation within 5%. The height of mass transfer unit HTU for RPB is calculated to be 1.60–2.07 cm, which is one order of magnitude lower than that of conventional reactors, indicating the investment of the desulfurization reactor can be greatly reduced by using RPB. [ABSTRACT FROM AUTHOR]

• Desulfurization by ionic liquid has been carried out in a RPB. • [CPL][TBAB]IL/PEG-400 as absorbent has the best performance. • No obvious loss of desulfurization efficiency was observed during reutilization. • Desulfurization with IL in a continuous process was feasible with RPB. Desulfurization by ionic liquids (ILs) has attracted wide attention since ILs as green solvents can be recycled after desorption. However, the high viscosities of ILs limit the sulfur dioxide (SO 2) absorption in gas-liquid contactors. In this work, a rotating packed bed (RPB) with excellent mass transfer performance was employed for SO 2 removal with caprolactam tetrabutyl ammonium bromide ([CPL][TBAB]) IL. Effects of rotational speed, temperature, liquid flow rate, and gas flow rate on the desulfurization efficiency were systematically studied. By optimization of the solvents, the desulfurization efficiency remains almost unchanged after multiple absorption and regeneration cycles, and the energy consumption during desorption process can also be reduced. These results indicated that the RPB combined with ILs has promising prospects for SO 2 absorption and desorption in sulfuric acid plants. [ABSTRACT FROM AUTHOR]