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Poly (ethylene glycol)-poly (n-butyl cyanoacrylate) (PEG-PBCA) is a remarkable drug delivery carrier for permeating blood-brain barrier. In this work, a novel high-gravity procedure was reported to intensify Knoevenagel condensation-Michael addition polymerization of PEG-PBCA. A series of PEG-PBCA containing different block ratios were synthesized with narrow molecular weight distribution of polydispersity indexes less than 1.1. Furthermore, the reaction time reduced 60% compared to conventional stirred tank reactor process. Chemical structures of as-prepared polymers were characterized. In vitro drug delivery performance was evaluated. The cytotoxicity of PEG-PBCA to brain microvessel endothelial cells (BMVEC) decreases with the extension of the PEG chain and the shortening of the PBCA chain. The polymer cellular uptake to BMVECs was better after improving hydrophilicity by PEG block. Results of blood-brain barrier permeability demonstrated that medium length of PBCA chain and short PEG chain are favorable for hydrophobic Nile red permeation, while long PEG chain and short PBCA chain are beneficial to delivery water-soluble doxorubicin hydrochloride (Dox). The average apparent permeability coefficient increased 1.7 and 0.25 times than that of raw Nile red and Dox, respectively. High-gravity intensified condensation polymerization should have great potential in brain drug delivery system.

The rotating packed bed (RPB) has been widely used in gas-liquid flow systems as a process intensification device, exhibiting excellent mass transfer enhancement characteristics. However, the complex internal structure and the high-speed rotation of the rotor in RPB bring significant challenges to study the intensification mechanism by experiment methods. In the past two decades, Computational Fluid Dynamics (CFD) has been gradually applied to simulate the hydrodynamics and mass transfer characteristics in RPB and instruct the reactor design. This article covers the development of the CFD simulation of gas-liquid flow in RPB. Firstly, the improvement of the simulation method in the aspect of mathematical models, geometric models, and solving methods is introduced. Secondly, new progress of CFD simulation about hydrodynamic and mass transfer characteristics in RPB is reviewed, including pressure drop, velocity distribution, flow pattern, and concentration distribution, etc. Some new phenomena such as the end effect area with the maximum turbulent have been revealed by this works. In addition, the exploration of developing new reactor structures by CFD simulation is introduced and it is proved that such new structures are competitive to different applications. The defects of current research and future development directions are also discussed at last.

Renewable bio-based electromagnetic interference (EMI) shielding materials receive increasing attention undoubtedly. However, there is still a challenge to use raw biomass materials to construct a significant structure through an effortless and environmental route for EMI shielding applications. Herein, for the first time, we demonstrated a hybrid composite of multi-walled carbon nanotube/polypyrrole/chrome-tanned collagen fiber (MWCNT/PPy/CF), which utilized waste chrome shavings as a matrix. X-ray photoelectron spectroscopy reveals that the chromium on the CF has a binding effect on the PPy layer, which endows the tight integration between the CF and PPy layer. After the MWCNT network was loaded on the PPy layer, this ternary structure could provide stable conductive paths and a rich number of polarized interfaces. The MWCNT/PPy/CF composite exhibits superior electrical conductivity (354 ± 52 S/m), higher than PPy/CF (222 ± 38 S/m) and MWCNT/CF (104 ± 11 S/m), owing to the synergy of dual conductive structures. Notably, the shielding effectiveness (SE) value of the MWCNT/PPy/CF composite reaches 30 dB in the X band at a thickness of 0.48 mm. The shielding effectiveness of reflection (SE

This work presented experimental and modeling studies on the simultaneous absorption of H2S and CO2 into the N-methyldiethanolamine (MDEA) and piperazine (PZ) solution in a rotating packed bed (RPB...

The work herein employed COMSOL Multiphysics simulation and experiment to study the temperature distribution of water in a specially designed cylindrical microwave (MW) reactor with two magnetrons....

Polymerization of isobutylene (IB) for synthesizing highly reactive polyisobutylene (HRPIB) is characterized by a complicated fast intrinsic reaction rate, therefore, the features of its products exhibit a strong dependence on mixing efficiency. To provide uniform and efficient mixing, a rotating packed bed was employed as a reactor for polymerization of IB. The effects of operating parameters including polymerization temperature (T), rotating speed (N) and relative dosage of monomers and initiating systems ([M]0/[I]0) on number-average molecular weight (Mn) of HRPIB were studied. HRPIB with Mn of 2550 g·mol−1 and exo-olefin terminal content of 85 mol% were efficiently obtained at suitable conditions as T of 283 K, N of 1600 rpm and [M]0/[I]0 of 49. Moreover, the Mn can be regulated by changing T, N and [M]0/[I]0. Based on the presumptive-steady-state analysis method and the coalescence–redispersion model, a model for prediction of the Mn was developed and validated, and the calculated Mn values agreed well with experimental results, with a deviation of ±10%. The results demonstrate that RPB is a promising reactor for synthesizing HRPIB, and the given model for Mn can be applied for the design of RPB and process optimization.

Rotating packed beds (RPBs) have attracted widespread attention due to their high mass transfer efficiency. In this paper, gas flow characteristics in a rotating spherical packing bed (RSPB) were i...

A facile and scalable route, using the high-gravity reactive precipitation method which was carried out in a rotating packed bed (RPB) reactor, was proposed to synthesis α-Fe2O3 catalyst which is used to catalyze the decomposition of solid propellants. The effect of high-gravity level (G) of RPB reactor on the particle size and its distribution of α-Fe2O3 was explored. It was found that increasing the G of RPB is beneficial for the formation of α-Fe2O3 with smaller particle size and narrower size distribution. The α-Fe2O3 nanoparticles around 85 nm with narrow size distribution could be synthetized when G is higher than 120. The catalytic performance of the as-synthesized α-Fe2O3 on the thermal decomposition of ammonium perchlorate (AP) was performed by differential scanning calorimetric (DSC) method. DSC results show that adding 2 wt% as-prepared 84 nm α-Fe2O3 can decrease the temperature of low-temperature decomposition (LTD) and high-temperature decomposition (HTD) of AP by 14.4 °C and 53.4 °C respectively, and increase the heat released of AP's thermal decomposition process from 864 J/g to 1235 J/g. Besides, result of DSC test and kinetic analysis indicated that the catalytic performance of α-Fe2O3 on the thermal decomposition of AP increased with lessening the average particle size of α-Fe2O3.

Sulfonation process usually exhibit high reaction rate and low yield and selectivity of product in common reactors for its insufficient micromixing. This work employed a rotating packed bed (RPB) to intensify the micromixing of the phenol sulfonation process to improve the yield and selectivity of p-hydroxybenzenesulfonic acid (p-HBSA). Experiments and kinetic study on the sulfonation of phenol by concentrated sulfuric acid were carried out in a stirred tank reactor (STR). The reaction rate constant k and activation energy E at certain temperature was tested. The values of pre-exponential factor and activation energy were obtained as follows: k1 = 5.74 × 103, E1 = 8.17 kJ/mol, k-1 = 6.95 × 103, E-1 = 6.18 kJ/mol, k2 = 1.43 × 1010, E2 = 69.35 kJ/mol, k-2 = 0.05 × 103, E-2 = 14.17 kJ/mol. The effects of various operating conditions including reaction temperature (T), sulfuric acid/phenol molar ratio (η), solvent/phenol molar ratio (ζ), concentrated sulfuric acid feeding rate (Q′), stirring speed (P), ageing time (τ), on the content of p-HBSA were investigated in an attempt to obtain the optimal operating conditions in the STR. The yield of p-HBSA is 89.85% at the optimal operating conditions. On the basis of the results in STR, further experiments were performed in a rotating packed bed (RPB) to improve the sulfonation reaction selectivity and p-HBSA yield. The effects of rotation speed (N), cycle time (t) and concentrated sulfuric acid feeding rate (Q) were investigated. Results show that the yield of p-HBSA can reach up to 96.52% in RPB at the optimal operating conditions of N = 2250 rpm, Q = 300 mL/min, T = 100 °C, η = 1.1, τ = 25 min, ζ = 1.25 and t = 3 min. The yield of p-HBSA obtained in the RPB is 6.67% higher than that in the STR. The research exhibits that RPB can obviously improve the yield of p-HBSA.

Absorption of carbon dioxide into sodium hydroxide solution has been extensively used for mass transfer investigation in gas–liquid contacting reactors. To obtain a reliable value of effective mass transfer area (A), the selection of fundamental parameters, such as reaction rate constant, diffusion coefficient, and solubility data, is significant for data processing, and very little literature has been reported on the selection of these parameters. Therefore, an evaluation of the sources of fundamental parameters needs to be given. In this work, six parameter sources, including classic literature and newly published papers, were evaluated for effective mass transfer area measurement in a rotating packed bed. Quantitative comparisons demonstrated that using different reaction kinetics models will cause a large deviation in the values of the effective mass transfer area. Further, the inconsistency between the sources of kinetics models and physical properties can also cause a large deviation, which should b...

In this work, the absorption performance of SO2 into calcium-based solution was studied in a rotating packed bed (RPB). Experiments were carried out to examine the effect of various operating parameters on the desulfurization efficiency, such as absorbent pH value, gravity level of RPB, gas-liquid ratio, gas treatment amount and inlet SO2 concentration. It was found that the SO2 removal efficiency increased with the increasing of absorbent pH value and RPB gravity level, and decreased with the increasing of the gas-liquid ratio and inlet SO2 concentration. SO2 removal efficiency was about 88% for the metal packing and 82% for the plastic packing under the optimal operating conditions when the SO2 inlet concentration was 900 mg/m3. Moreover, volumetric mass transfer coefficient (KGa) in RPB of this absorption process was calculated. It was found that KGa was 7.83–19.34 s−1 in RPB, almost 1 order of magnitude higher than that in packed tower and impinging stream gas-liquid reactor.

This study employed a rotating packed bed (RPB) to enhance the absorption process of NOx and SO2 into Na2SO3 solution with the preoxidation by ozone. The absorption performance of NOx and SO2 was e...

Nanosheet (S) and nanoplate (P) γ-Al2O3 were synthesized by simple hydrothermal methods and employed as supports for Ni catalysts in CO2 methanation. Both of the nanostructured Ni/Al2O3 catalysts displayed good activity. In comparison, the Ni/Al2O3-S catalyst showed higher CO2 conversion than the Ni/Al2O3-P counterpart at the reaction temperature ranging from 250 to 400 °C. The physical and chemical properties of the catalysts were systematically characterized by N2 sorption, X-ray diffraction (XRD), high resolution-transmission electron microscopy (HR-TEM), hydrogen temperature-programmed reduction (H2-TPR) and CO2 temperature-programmed desorption (CO2-TPD) techniques. Higher specific surface area and stronger metal-support interactions were confirmed on the Ni/Al2O3-S catalyst, which may lead to smaller particle size of Ni nanoparticles. Moreover, the Ni/Al2O3-S catalyst possessed more abundant weak and medium basic sites, which would benefit the activation of CO2. The smaller Ni size and more suitable basic sites may rationalize the superior activity of the Ni/Al2O3-S catalyst. Besides, the Ni/Al2O3-S catalyst exhibited excellent stability at 325 °C for 40 h.

Anthrahydroquinone oxidation and H2O2 extraction are essential steps for commercial production of H2O2 via the anthraquinone route. However, high demand of mass transfer in the oxidation and extraction for the complicated production procedure is still a challenge. In this work, a rotating packed bed (RPB) reactor with superior mass transfer efficiency was applied to the simultaneous oxidation reaction and extraction for the first time. Effects of various operating parameters on the efficiency of reactive extraction were investigated. The intensified gas-liquid-liquid mass transfer in the tandem RPB reactor + stirring tank reactor (STR) contributed to the anthrahydroquinone conversion and H2O2 extraction efficiency up to 92% and 89%, respectively, while only 9.1% and 69% in the STR. Compared with the bubble column, the RPB reactor + STR also showed higher H2O2 production efficiency and obvious advantage with a shorter reaction time, which paves a new way for gas-liquid-liquid reactive extraction.

Micromixing performance of reactors has great influence on fast reactions such as polymerization, pharmaceutical and crystallization applications. In this work, based on Villermaux–Dushman iodide–iodate reaction system, an experimental investigation of micromixing with non-Newtonian fluid (CMC solution) in a rotation packed bed (RPB) was carried out. And a two-dimensional RPB Computational Fluid Dynamics (CFD) model coupled with shear-thinning rheological property was developed. Both experimental and numerical results indicated that increasing rotational speed could dramatically improve the micromixing performance due to the shear-thinning behavior in the RPB. Especially, the CMC concentration was an important factor that should be carefully considered, which showed quite different impacts on micromixing efficiency with liquid flow rate. In addition, based on incorporation model and experimental results, the micromixing time of the RPB with non-Newtonian fluid was determined as 4.1 × 10−4 s–1.9 × 10−3 s. This fundamental research had guiding significance for practical operations of RPBs when processing non-Newtonian fluids.

Coal still has a vital role in power generation, and coal-fired power plants are considered to be a main source of CO2 emission. This work proposed a process intensification (PI) technology, combining the highly efficient diethylenetriamine (DETA) solvent for CO2 absorption and the PI device of rotating packed bed (RPB) for enhancing gas-liquid mass transfer, to improve CO2 capture performance. Experimental study was conducted in a lab-scale RPB, and the dependences of CO2 removal performance on various operation conditions were systematically investigated. It was founded that CO2 loading has a vital effect on removal efficiency, and increasing rotation speed and solvent flow rate is beneficial to CO2 removal. The comparison of mass transfer performance between RPB and packed column (PC) demonstrated that the gas retention time in RPB with a value of 1.5 s is far shorter than that in PC under the similar operation conditions, which means RPB possesses a great advantage of shrinking mass-transfer device’s size for the CO2 capture process. Additionally, a Back-Propagation Neural Network (BPNN) model was developed for predicting the value of overall volumetric mass-transfer coefficient (KGav), and the predicted values agree well with experimental data with a satisfactory average absolute relative derivation (AARD) of 7.85%. These results demonstrated that this PI technology is expected to be a competitive candidate for improving CO2 capture performance from flue gas.

A novel rotating packed bed (RPB) reactor is first adopted to intensify the reaction of isobutane alkylation with 2-butene catalyzed by H2SO4. This work investigated reaction performance, and reaction conditions were optimized. Under the optimal conditions, the research octane number (RON) reached 98.85. Meanwhile, the yields of C8 and trimethylpentanes were 90.65% and 85.47%, respectively. The reaction efficiency was tremendously improved by using RPB due to its high efficiencies of mass transfer and micromixing. More importantly, the inner mole ratio of isobutane to 2-butene was dramatically decreased in RPB, which means the energy cost of material cycling in the alkylation process could be extremely reduced. Moreover, an empirical correlation model was proposed to predict the multiproduct yields and RON with a deviation within ±10%. In conclusion, RPB reactor is a highly promising industrial platform for the process of H2SO4 alkylation.

To ensure steady operation of gas transmission lines and meet the utilization specification of downstream processes, gas dehydration is employed in offshore natural gas production, where urgent demands for space and size exist. In this work, a rotating packed bed (RPB) was used to intensify the triethylene glycol (TEG) dehydration process and the effects of operating variables on the overall volumetric mass transfer coefficient (Kya) and height of mass transfer unit (HTU) were investigated. The value of HTU in a RPB was measured to be 4.3–7.9 mm, which was at least an order of magnitude lower than that in conventional columns, indicating the significant reduction in the size of the dehydration apparatus. The predicted Kya matches well with the experimental data, and the mean relative error (MRE) is only 6.68%.

This work presents a novel process of nano-Ni preparation by liquid reduction method without surfactant in a combined reactor of a rotating packed bed (RPB) and a stirred tank reactor (STR). The reaction mechanism of this process was studied, and the effects of different operating conditions including rotation speed, NaBH4 concentration, liquid volumetric flow rate, and liquid circulation time on the characteristics of the nano-Ni were systematically investigated in the RPB to control the morphology and average particle size of the prepared nano-Ni. The average particle size of the prepared nano-Ni can be adjusted from 42 to 130 nm by changing operating conditions, and the prepared nano-Ni with a face centered cubic (FCC) structure, an average particle size of 42 nm, and a particle size distribution of 30–60 nm was obtained under the optimal operating conditions. This research provides a novel pathway and theoretical basis for controllable preparation production of nano-Ni.

A novel multiliquid-inlet rotating packed bed (MLI-RPB), compared to the conventional RPB, was demonstrated to result in higher gas–liquid mass-transfer in our previous studies (Chu et al., Ind. En...

Processing viscous fluid system in industrial applications is one of the challenges in process intensification. In this work, a two-dimensional CFD model was developed to reveal viscous liquid flow characteristics in the injection zone, inner cavity, packing zone and outer cavity of rotating packed bed (RPB). The CFD results agreed well with the published experimental data. The transition of the liquid flow pattern in RPB was discussed with operating conditions. The liquid viscosity showed no significant influence on the liquid holdup and the average diameter of droplets in RPB. In addition, the liquid holdup and droplet diameter decreased as rotational speed increased, and increased as liquid flow rate increased. Based on the simulated results of residence time distribution along radial direction, the end effect zone of RPB was specified, and a novel way was proposed to quantify the thickness of end effect zone. Results showed that the viscosity had great influence on the end effect zone, which had guiding significance for practical operations and configuration optimization.

Ni catalysts supported on nanosheet (S) and nanoplate (P) γ-Al 2 O 3 have been successfully synthesized for carbon dioxide (CO 2 ) reforming of methane. The Ni/Al 2 O 3 -S catalyst possessed excellent activity and stability whereas the Ni/Al 2 O 3 -P catalyst exhibited slightly lower activity and much worse stability. The Ni/Al 2 O 3 -S catalyst displayed much smaller size of Ni nanoparticles, which may explain the difference in activity. The Ni/Al 2 O 3 -S catalyst possessed enhanced anti-sintering and anti-coke properties, which would lead to an improved stability.

This study presents the synthesis of petroleum sulfonate (PS) via gas-phase SO3 sulfonation in a rotating packed bed (RPB) and the relationship between the interfacial tension (IFT) at the oil-aqueous interface and the composition of PS. Through the process optimization, the content of active matter in the prepared PS could reach up to 42.5%, which was significantly higher than that in the industrial production (38%). Moreover, the oil-aqueous IFT could reach an ultra-low value of 1.41×10-3 mN/m. The analysis results of PS composition and IFT indicated that the oil-aqueous IFT was mainly affected by the content of alkyl benzene, alkyl indane, alkyl acenaphthylene and alkyl naphthalene sulfonates in PS. In addition, a correlation coefficient, which was consistent with the interfacial tension, was established for evaluation of the similarity between PS samples.

In this study, hierarchical ZSM-5 zeolites are hydrothermally prepared using rotating packed bed (RPB) in premixing process (gelation stage). The impact mechanisms of RPB on the zeolite growth process are investigated. It is found that the zeolite precursor obtained by RPB contains abundant bubbles, and aluminosilicate aggregates in the precursor are broken and dispersed uniformly, which is beneficial for the uniform and fast growth of zeolite. Additionally, the effects of various RPB-premix process parameters, including rotation speed, premixing time, and liquid feed rate on the particle sizes of ZSM-5 are systematically investigated. The prepared ZSM-5 zeolites by RPB-premix route exhibit smaller particle sizes, narrower particle size distributions, larger specific surface areas, richer pore structure, and more acid amount compared with those by traditional premix treatment. Therefore, this study provides a novel approach for the synthesis of high-performance ZSM-5 zeolites.

Diazotization is common in the fine chemical industry however its kinetics study is rare. In this work, the stopped-flow technique was adopted to study the kinetic parameters of the diazotization reaction between p-nitroaniline and nitrous acid. The results revealed that the p-nitroaniline diazotization is a second-order reaction with excessive hydrochloric acid, and the reaction rate equation with a pre-exponential factor and activation energy of 6.95 × 108 L·mol−1·s−1 and 37.79 kJ·mol−1 respectively was obtained according to Arrhenius equation. In addition, the kinetic model was established, the correlated values of k1 matched well with the experimental values with an AAD of 7.1%. This work provides theoretical data and guidance for its process optimization.

Oxygen vacancy (OV) plays a significant role in the catalytic performance of oxidation catalysts. Herein, ZSM-5@MnOx catalyst with abundant OVs was firstly prepared by in-situ growth method. The prepared catalyst exhibits good catalytic activity for the selective oxidation of benzyl alcohol (BA) to benzaldehyde (BAD) with ~100% BA conversion and ~100% BAD selectivity within 3 h. We have proved that the OV in ZSM-5@MnOx catalyst is the main active site for the BA oxidation. Besides, the OV formation mechanism is proposed based on the influences of modified ZSM-5 supports on OVs. Results show that sodium ions in ZSM-5 are conducive to enhancing the coating of MnOx on supports, and protons in ZSM-5 are beneficial for the formation of OVs by dehydrating with hydroxyls on MnOx. Based on the mechanism, we further enrich OVs by the deep dehydration to improve its catalytic performance. This work provides a novel route for the design of OVs in the ZSM-5@MnOx catalyst.

This work presents the dispersion of Ni nanoparticles into the ethanol solution without surfactant in a rotating packed bed (RPB). The effects of different operating parameters on the particles size distribution (PSD) of Ni nanoparticles in the solution were investigated. Furthermore, the influence of dispersion process on the catalytic performance was investigated by the catalytic hydrogenation of cinnamaldehyde using Ni-Pt nanoparticles as catalyst. Also, a correlation to predict the average particles size (D[3,2]) was established, and the predicted D[3,2] fitted well to the experimental data with a deviation within 10%. The experimental results indicated that RPB could significantly intensify the dispersion of Ni nanoparticles in the solution, which is beneficial for the nano-catalysis reaction process. Catalytic results showed that the reaction rate of CAL obtained in RPB were about twice that in the stirring tank reactor at H2 pressure of 2 MPa.

Carbon dioxide (CO2) capture and storage (CCS) is currently the most effective technology to reduce CO2 emissions, but it has crucial issues of high energy consumption and low mass transfer efficiency in capture process. In this work, 2-amino-2-methyl-1-propanol (AMP), 2-(2-aminoethylamino)ethanol (AEEA), N-methyl pyrrolidone (NMP) tri-solvent blend is used as a novel non-aqueous absorbent for CO2 capture process in rotating packed bed (RPB) reactor, which is employed to intensify the mass transfer in both absorption and desorption process. The experimental results show that this new method has good absorption performance. When the CO2 loading of the lean absorbent is 0.035 mol CO2/mol amine, the CO2 capture efficiency is still 89% and the overall volumetric mass transfer coefficient (KGa) is 2.67 kmol·m−3·h−1·kPa−1. For desorption process, this study adopted the direct steam stripping (DSS) technique to reduce energy consumption. The optimal regeneration energy consumption by DSS of this non-aqueous absorbent in RPB is about 2.46 GJ/ton CO2, which is 36.6% lower than that in conventional reboiler regeneration process with 30% MEA solution. The results indicate that this new method has the advantages of high efficiency and low energy consumption, exhibiting good industrial application prospect.

The emission of CO2 is leading to serious global climate change, which has attracted increasing attention. In this work, a rotating packed bed (RPB) was employed as a highly effective reactor to intensify the CO2 absorption in an alkanolamine solution that mainly contained 2-(2-aminoethylamino)ethanol (AEEA). The effects of important operating conditions, such as high gravity level, amine solvent concentration, gas/liquid flow ratio, CO2 inlet concentration, absorption temperature, and CO2 loading in the amine solvent, on the gas-phase volumetric mass-transfer coefficient (KGa) and CO2 capture efficiency were investigated. The results indicated that the high gravity level and CO2 inlet concentration had significant effects on KGa, and the experimental value of KGa was found to be about 1.42–2.86 kmol·m–3·h–1·kPa–1 in the RPB, which is an order of magnitude higher than that in a conventional packed column. Furthermore, an artificial neural network (ANN) model was applied to predict the mass-transfer perfor...

The rotating packed bed (RPB) has drawn wide attention owing to its outstanding advantage in process intensification. In the present study, gas flow characteristics in RPB were investigated by particle image velocimetry (PIV) measurement. The velocity and turbulent kinetic energy (TKE) in the packing zone were obtained and the effects of various parameters were analyzed. During rotation, gas rapidly acquired tangential velocity, which was dominant in resultant velocity. Mean gas velocity increased with the increase of rotational speed, but was almost independent of gas flow rate and packing size at lower rotational speed. Moreover, mean radial and tangential slip velocities were overall positively affected by gas flow rate and rotational speed, respectively. Higher TKE near the inner packing than those in the bulk zone revealed the existence of a gas end-effect zone in RPB. The results could provide a theoretical basis for further study on gas–solid catalytic reaction or the gas–liquid mass transfer proce...

This study employed a rotating packed bed (RPB) to enhance the absorption performance of nitrogen oxides (NOx) into sodium hydroxide (NaOH) solution with the preoxidation of NO by ozone. The absorption performance of NOx was evaluated in terms of its removal efficiency (η) from a gas stream under various operating conditions including O3/NOx molar ratio (MR), rotation speed of the RPB (N), liquid flow rate (L), NaOH concentration (CNaOH), inlet NOx concentration (CNOx), and using time (t). Also, the corresponding effect of adding oxidants (NaClO, H2O2, and KMnO4) and a reductant (CO(NH2)2) into the NaOH solution on NOx removal efficiency was investigated. Results indicated that preoxidation of NO by O3 significantly improved NOx removal efficiency and the removal efficiency increased with increasing O3/NOx molar ratio, NaOH concentration, and liquid flow rate but decreased with increase in inlet NOx concentration and using time. Additionally, NOx removal efficiency first increased and then decreased with ...

The shortage of low-sulfur coking coal will bring about an increasingly high hydrogen sulfide (H2S) in the coke oven gas (COG) in the near future. This work investigated the removal of hydrogen sulfide (H2S) from a simulated coke oven gas (COG) by catalytic oxidative absorption in a rotating packed bed (RPB). Sodium carbonate (Na2CO3) solution doped with 20 mg L−1 of a commercial “888” catalyst was used as the absorbent. The removal efficiency of H2S was evaluated under various operating conditions including rotation speed of the RPB (N), liquid-gas ratio (L/G), inlet H2S concentration ( c H 2 S,in ), temperature (T) and Na2CO3 concentration ( c Na 2 CO 3 ) in an attempt to optimize the conditions. The results were validated by comparison with those of separate experiments conducted in a packed column comprising a high-efficiency laboratory packing of Dixon rings. The comparison results reveal that the RPB exhibited higher H2S removal efficiency than the packed column, indicating it as an efficient gas-liquid contactor with a greater potential to remove H2S from COG.

This article presents modeling and experimental study on the sulfonation of alkylbenzene to synthesize alkylbenzene sulfonate in a rotating packed bed (RPB) reactor. The effects of some important operating and reactor parameters, such as rotating speed of RPB reactor, liquid flow rate, SO 3 molar concentration in sulfonating agent, reaction temperature, and packing thickness of RPB on the alkylbenzene sulfonated ratio were investigated. In addition, a coalescence-redispersion mathematical model was established to predict alkylbenzene sulfonated ratio in RPB, and the validity of the model was confirmed by the fact that most of the predicted alkylbenzene sulfonated ratio agreed well with the experimental data with a deviation within 12%. The experimental and numerical results showed that an improvement of the alkylbenzene sulfonation performance in RPB reactor could be achieved by optimizing the RPB rotating speed and total reactant liquid flow rate, decreasing the SO 3 concentration in sulfonating agent and properly increasing the react temperature and RPB packing thickness.

Micromixing performance in reactor is one of the key factors for fast reaction systems, such as fine chemicals, pharmaceutical and crystallization. In this work, a three-dimensional CFD model was developed for analyzing flow characteristics and micromixing efficiency in microporous tube-in-tube microchannel reactor (MTMCR). PDF transport model based on Lagrangian Monte Carlo method and a modified Finite-rate/Eddy dissipation model were used to build micromixing model, respectively. The effects of Reynolds number and flow ratio on micromixing efficiency were studied using Villermaux–Dushman iodide–iodate reaction system. The segregation index X S is used to quantify the micromixing performance. The results showed that X S decreased with the increasing of Re and the decreasing of flow ratio R , and simulated values agreed well with published experimental data. Based on the modified Finite-rate/Eddy dissipation model, the parallel competing reaction system was analyzed by taking into account mixing-controlled and kinetic-controlled factors, which explained how this model worked. Moreover, porous diameter and width of annular channel were optimized to improve the micromixing efficiency of MTMCR, and the optimal values were 20 μm and 250 μm, respectively.

Helical tube reactors (HTRs), utilizing the secondary flow to intensify chemical processes, have been applied in many fields. The increasing application of liquid-liquid two phases systems in HTRs necessitates a knowledge of liquid-liquid dispersion performance. In this work, a novel HTR, which comprised two main parts, i.e. a pre-dispersion unit and a helical tube, was designed for the liquid-liquid dispersion processes. The pre-dispersion unit was a straight tube packed with nickel foam elements, used to adjust the mean droplet diameter of the dispersed phase for the HTR. Effects of various parameters, such as the number and pore diameter of nickel foam elements, volumetric flow ratio, and curvature ratio on the pressure drop and liquid-liquid dispersion were experimentally investigated by using a water/Tween 80/cyclohexane system. According to the results of the pressure drop, the relationship between Sauter mean diameter (SMD) and mean energy dissipation rate was discussed. In addition, a correlation is established to predict the SMD in the HTR. Corresponding empirical correlations were d 32 = 145 e m − 0.3 for the energy dissipation rate and SMD, and by d 32 / D m = 0.80 W e c − 0.32 D e − 0.24 n e − 0.15 ψ 0.68 for the SMD in function of the relevant properties of the system, respectively.

The work herein describes a novel technique, a rotating packed bed (RPB) combined with a charged device, to remove fine particles from gas steam. Experiments were carried out to investigate the effects of different operating conditions, including the packing type, packing thickness, rotation speed, gas–liquid volumetric ratio, initial fine particle concentration, and voltage, on the removal efficiency of fine particles from a gas stream. Results show that total removal efficiencies of fine particles and particles with a size of less than 2.5 μm (PM2.5) can reach up to 99 and 96%, respectively, under the operating conditions of packing thickness of 60 mm, rotation speed of 1000 rpm, gas–liquid volumetric flow ratio of 400, voltage of 40 kV, and use of a fine metal gauze packing. In addition, a correlation to predict PM2.5 removal efficiency was established, and results show that the predicted values of outlet PM2.5 concentrations are in agreement with experimental data, with deviations of ±20%. This work d...

Using catalytic oxidative absorption for H2S removal is of great interest due to its distinct advantages. However, traditional scrubbing process faces a great limitation in the confined space. Therefore, there is an urgent demand to develop high-efficiency process intensification technology for such a system. In this article, H2S absorption experimental research was conducted in a rotating packed bed (RPB) reactor with ferric chelate absorbent and a mixture of N2 and H2S, which was used to simulate natural gas. The effects of absorbent pH value, gas–liquid ratio, gravity level of RPB, absorption temperature and character of the packing on the desulfurization efficiency were investigated. The results showed that H2S removal efficiency could reach above 99.6% under the most of the experimental condition and above 99.9% under the optimal condition. A long-time continuous experiment was conducted to investigate the stability of the whole process combining absorption and regeneration. The result showed that the process could well realize simultaneous desulfurization and absorbent regeneration, and the H2S removal efficiency kept relatively stable in the whole duration of 72 h. It can be clearly seen that high gravity technology desulfurization process, which is simple, high-efficiency, and space intensive, has a good prospect for industrial application of H2S removal in confined space.

This study presented an experimental investigation on the capture of fine particles from gas stream by water in a rotating packed bed (RPB). Experiments were carried out to investigate the effects of different operating conditions including packing types, rotation speed, gas-liquid volumetric ratio, inlet particle concentration, and gas temperature on the removal efficiency of fine particles. The overall removal efficiency of fine particles can reach 98 % under the optimal operating conditions, which are a rotation speed of 1200 rpm, a gas-liquid volumetric ratio of 600, a gas temperature of 100 °C, and the use of fine metal gauze packing. In addition, the correlation of removal efficiency of fine particles was deduced. It is observed that the predicted removal efficiency and outlet concentration of fine particles are in good agreement with the experimental values, with deviations within 10 % and 20 % respectively. This process exhibits the potential application of RPBs in simultaneous removal of fine particles and SO2 by liquid solution.

In order to reduce SO2 emissions and achieve green utilization of sulfur resources, a desulfurization method of SO2 removal using hydrogen peroxide (H2O2) in rotating packed bed (RPB) is proposed. It can not only achieve the efficient removal of SO2, 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 H2O2 and SO2 in RPB. The influences of different operating conditions including RPB rotating speed, H2O2 mass fraction, gas–liquid volumetric flow rate ratio, gas flux, and inlet SO2 concentration on desulfurization performance were studied. Under the optimized conditions, it turned out that the desulfurization efficiency was above 99% and the outlet SO2 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.

In this work, petroleum sulfonate (PS), which can be used for enhanced oil recovery (EOR), was synthesized by sulfonation of distillate oil using gaseous SO3 in a rotating packed bed. The prepared PS was characterized by FT-IR, NMR, negative electrospray ionization fourier transform ion cyclotron resonance mass spectrometry [(−) ESI FT-ICR MS] and thermal gravimetric analysis (TGA). Results showed that the PS contains N1, O1, O2, O3, N1O2, O3S, O4S, and N1O3S classes, among which O3S, O4S, and N1O3S are the three main classes. And the chemical composition of the PS was obtained by the combined analysis of the double-bond equivalent (DBE) and carbon number (CN). TGA results showed that PS is thermally stable at the conventional reservoir temperature (less than 200 °C). In addition, the EOR performance of PS was studied by measuring surface tension, interfacial tension (IFT), wettability alteration and core-flooding experiments. Critical micelle concentration (CMC) of the prepared PS with a value of 0.2% was also determined by surface tension method. An ultra-low oil-water IFT value 1.327 × 10−3 mN/m was obtained at the CMC of PS solution. It was also found that adding PS into brine can decrease the contact angle below 90°, indicating that it can alter the rock wettability from oil-wet to water-wet surface which contributes to enhancing oil recovery. Finally, core-flooding experiments were carried out with different PS concentrations. The results showed that an additional recovery of about 30% after conventional water flooding can be obtained at a PS concentration of 0.3%. This study indicated that the PS synthesized by gas-phase SO3 sulfonation in RPB has good EOR performance, and the work is helpful for the learning of the relationship between PS composition and EOR performance and give the guidance for PS’s synthesis.