Based on the framework of the rotating zigzag bed (RZB), the crossflow concentric-baffle rotating bed (CRB) was proposed, with the rotor containing a set of perforated concentric baffles. In the first paper in this series, the distillation performance of the CRB was studied and compared with that of the RZB. It was found that the CRB showed the poorer mass-transfer efficiency than the RZB, which led to an obvious loss in pressure drop and shaft power. Three possible main factors affecting the mass-transfer performance of the CRB (i.e., liquid distribution, seal, and flow pattern) were identified and experimentally investigated. The results revealed that the CRB had a good liquid self-distribution and could dispense with the liquid distributor. The elimination of the liquid distributor significantly enhanced the mass-transfer performance despite a moderately higher pressure drop. For the CRB, the gland seal was preferred due to its great advantage over labyrinth seal in mass transfer, although it caused an additional power consumption, which could be reduced by the selection of proper seal materials. The introduction of counter-current contact in the CRB rotor could not improve its mass-transfer performance but, instead, increased the pressure drop and shaft power required. The favorable gas–liquid contact pattern in the CRB rotor was cross-current. The optimized CRB was obtained based on the above results and compared with the RZB. The comparison demonstrated that, when the size of the rotor was same, the optimized CRB showed no poorer mass-transfer performance, much lower pressure drop, and shaft power than the RZB especially at the higher loads. Therefore, the optimized CRB could be potentially applied in gas–liquid contacting processes with a larger throughput.

Vapor−liquid equilibrium (VLE) data were measured for the ternary system water (1) + ethanol (2) + 1-hexyl-3-methylimidazolium chloride ([hmim]Cl) (3) at p = 100 kPa. Six sets of complete T, x, y data were reported. While the mole fraction of ethanol on an ionic liquid (IL)-free basis was fixed, respectively, at 0.1, 0.2, 0.4, 0.6, 0.8, and 0.98, measurements were performed in a way in which the IL mass fraction varied from 0.8 to 0.1, in an interval of 0.1. The NRTL equation was used for correlation and was revealed as adequate for the ternary system in the experimental composition range. The quality of correlation appeared to be sensitive to the parameters used for water + ethanol. The ternary VLE behavior was also modeled by correlation of two data sets, in which the ethanol mole fraction on an IL-free basis is, respectively, at 0.1 and 0.98. In this way, the six data sets were reproduced satisfactorily, with root-mean-square deviations of 0.49 K for temperature and 0.0042 for vapor phase mole fraction. Owing to the regular distribution of the experimental compositions, the feasibility of the correlation−prediction procedure was graphically presented, and in some sense visualized, in terms of relative volatility, activity coefficient, and bubble temperature, showing good agreement between experiment and calculation.

•The HB interaction between IL and UFAMEs is proposed.•Cosolvents improve the dissolution of FAMEs and extraction ability of ILs.•The extracting performance of IL relies on the HB acidity/basicity of cosolvents.

Waste animal carcasses from livestock farming present serious potential problems for the environment and public health. Systems to dispose of carcasses should be safe but also economically and environmentally sustainable. In this study, the pig carcasses were tested for their potential as a renewable resource for the production of biodiesel and biogas. First, pig carcasses were sterilized under high temperature, which also yielded pig fat and organic slurry. Next, the pig fat and organic slurry were used as feedstocks to produce biodiesel and biogas. The results indicated that the yield of animal fat from the pig carcasses was about 20%. The rate of biodiesel conversion from the pig fat was 87%. The prepared biodiesel had the following characteristics: density, 881 kg/m3; kinematic viscosity, 4.5 mm2/s; flash point, 182 °C; water content, 220 mg/kg; and acid value, 0.3 mg KOH/g. These met the EN 14214 standard for biodiesel. After 30 days of digestion, the biogas yield from the organic slurry was 450 mL/g VS. The average CH4 content of the biogas was 63%. An economic evaluation showed that based on a capacity of 1 million pig carcasses the disposal plant would generate a net income of $56/tonne. The results of this study demonstrated that there is a significant potential for the use of pig carcasses as a renewable resource for the production of biofuels.Keywords: Animal carcasses; Biodiesel; Biogas; Renewable resources

Liquid entrainment in high-gravity (HIGEE) devices exists and reduces the separation efficiency. The flooding in HIGEE devices, called HIGEE flooding, sets an upper limit of allowable throughputs, and different flooding criteria were proposed by researchers. Using an air–water system, the experiments of liquid entrainment and HIGEE flooding were carried out in a rotating zigzag bed (RZB), as a new HIGEE device. The RZB rotor had an inner diameter of 0.101 m, an outer diameter of 0.284 m, and a height of 0.051 m. The distillation experiment was conducted in the same RZB to investigate the effect of liquid entrainment on the separation efficiency. The results show that liquid entrainment in RZB contains liquid-droplet and liquid-film entrainment. Liquid-film entrainment is far higher than liquid-droplet entrainment. Also, excessive liquid-film entrainment at the outer edge of the RZB rotor severely lowered the separation efficiency. The point at which the pressure drop increases sharply with increasing superficial liquid velocity was the first to be taken as a new HIGEE flooding criterion. The new HIGEE flooding criterion reflected the real flooding in RZB, and the previous criteria could not reflect it. The new HIGEE flooding criterion can also be applied in rotating packed beds.

A new kind of high-gravity device—the crossflow concentric-baffle rotating bed (CRB)—has been developed, the rotor of which contains a set of perforated concentric baffles. In this type of rotating bed, the gas flows in a zigzag pattern toward the center of the bed while the liquid traveled radially from the inside to the outside of the rotor. Between the adjacent concentric rings, the gas phase could be fully kept in contact with the dispersed liquid phase in crossflow. The rotor structures and the two-phase flow arrangements determined its potential features, such as the low shaft power and the little backmixing, which, together with stagewise contacting, were favorable to multistage separation processes widely used in chemical process industries. In a pilot CRB, the pressure drop, shaft power, and mass-transfer performance were investigated under different operation conditions. The experimental results showed that the pressure drop, the shaft power, and the efficiency in each theoretical stage fell within the range of 100–600 Pa, 100–250 W, and 10%–15%, respectively. Compared to the rotating zigzag bed (RZB), the CRB generated a lower pressure drop and needed less shaft power for every contacting stage, which can be attributable to its different structures. However, the stage efficiency of the CRB was, at most, one-third as much as that of the RZB. This rather poor mass-transfer performance of the CRB shadowed, to a large degree, its advantages in the pressure drop and shaft power reductions. Therefore, it was necessary to optimize the structures of the CRB and enhance its mass-transfer performance.

Developed from rotating zigzag bed (RZB), the counterflow concentric-ring rotating bed uses a rotor composed of stationary–rotating discs, a set of concentric circular rotating rings with perforations, and a liquid distribution at the eye of the rotor, preserving the outstanding characteristics of RZBs consisting of intermediate feeding and multirotors coaxially installed in series in a casing. A mass-transfer model was proposed from which the local gas- and liquid-side mass-transfer coefficients, gas–liquid effective interfacial area, and height equivalent to theoretical plate (HETP) can be calculated. Total reflux distillation experiments were conducted in a counterflow concentric-ring rotating bed at atmospheric pressure using an ethanol–water system, and the mass-transfer end effects were also investigated. The experimental values of overall volumetric gas-side mass-transfer coefficient and HETP agree with the calculated values very well. Obvious end effects exist in the distillation process, and a correlation which takes inner and outer end effects into consideration is given. Compared with RZB, the counterflow concentric-ring rotating bed has lower mass-transfer efficiency, but it has gas–liquid throughput at least 5.576 times greater than that of RZB. Compared with rotating packed bed, the concentric-ring rotating bed has a much higher local gas-side mass-transfer coefficient.

(2R,3S,4S,5S)-6-(Hydroxymethyl)-tetrahydro-2H-pyran-2,3,4,5-tetraol (d-glucose) solubility in 1-dodecanol, 1-decanol, and 1-octanol from 343.15 K to 393.15 K was determined, respectively. The solubility of d-glucose increased with an increase in temperature and decreased with the increase of fatty alcohol chain length. The modified UNIQUAC model, S-UNIFAC model, and mS-UNIFAC model were applied to predict the solubility data; the interaction parameters were determined. Of the three models, the modified UNIQUAC model showed better prediction accuracy.

The pressure drop across “Higee”, a synonym for high-gravity technology, is one of the most important characteristics, and the liquid flow gives rise to intriguing and unusual effects on the pressure drop. The pressure drop of the wet Higee can be substantially lower than that of the dry one. This trend is quite different from the conventional packed and trayed tower. And the unusual effects also occur in the rotating zigzag bed (RZB), a novel type of Higee. The pressure drop of RZB was studied by two methods of the pressure drop model, based on gas tangential velocity and empirical correlation. By use of an air–water system, experiments were carried out in a RZB with a rotor that had an inner diameter of 214 mm, outer diameter of 486 mm, and axial height of 104 mm. The radial distribution of gas tangential velocity in the RZB rotor was measured by a five-hole pitot probe. Lliquid flow reduced the gas tangential velocity due to the drag exerted by liquid droplets on the gas. The gas tangential velocities were correlated by an empirical equation on which the centrifugal pressure drop was predicted accurately. The correlation of the frictional pressure drop was subsequently obtained. As a result, the pressure drop model based on gas tangential velocity was established, from which the phenomenon that the wet rotor pressure drop is lower than the dry rotor pressure drop was reasonably explained. The rotor and overall pressure drops of RZB were correlated by empirical equations with good agreement. Deviation of the rotor pressure drops based on experiments and on gas tangential velocity was less than that based on experiments and on empirical equations. Variation of the overall pressure drop of RZB was similar to that of the rotor pressure drop. The pressure drop model based on gas tangential velocity can also be applied to the conventional rotating packed bed, which is beneficial to the theory of the pressure drop of Higee.

Titanium-containing mesoporous silica TiO2/MCM-41 (C) was prepared by impregnating MCM-41, pretreated by refrigeration at 278 K, with aqueous TiCl4 solution as titanium precursor. In addition, TiO2/MCM-41 (H) was produced by same method but the support MCM-41 without refrigeration in order to investigate the influence of unrefrigerated pretreatment on the structure of TiO2/MCM-41. The dispersion and nature of titanium species were characterized by inductively coupled plasma mass spectrometry (ICP-MS), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–visible diffuse reflectance spectra (UV-vis DRS), standard Brunauer–Emmnett–Teller (BET), X-ray photoelectron spectra (XPS), scanning electron micrographs (SEM), transmission electron microscopy (TEM). The results indicate that TiO2/MCM-41 (C) showed better mesoscopic order, higher dispersion of titanium oxide species, stronger interaction with the MCM-41 support. But the pore size decreases from 3.4 to 2.4 nm when the titanium content increases to 76.6 mg/g. TiO2/MCM-41 (C2) exhibits more excellent catalytic performance than others, and the 97.6% conversion of methyl oleate (MO) and 93.1% selectivity to epoxidation methyl oleate (EMO) can be obtained at 353 K for 10 h.Graphical abstractHighlights► TiCl4 as titanium source. ► Post-synthesis by impregnating MCM-41 with aqueous TiCl4 solution. ► The support pretreated by refrigeration is of crucial importance for the nature of catalyst. ► Epoxy catalytic activity largely depends on the nature of titanium oxide species on the support.

Mesoporous materials possess a hexagonal array of uniform mesopores, high surface areas, and moderate acidity. They are one of the important catalysts in the field of catalytic pyrolysis. In this paper, mesoporous materials of Al-MCM-41, La-Al-MCM-41, and Ce-Al-MCM-41 were synthesized, characterized, and tested as catalysts in the cellulose catalytic pyrolysis process using a fixed bed pyrolysis reactor. The results showed that mesoporous materials exhibited a strong influence on the pyrolytic behavior of cellulose. The presence of these mesoporous molecular sieve catalysts could vary the yield of products, which was that they could decrease the yield of liquid and char and increase the yield of gas product, and could promote high-carbon chain compounds to break into low-carbon chain compounds. Mesoporous molecular sieve catalysts were benefit to the reaction of dehydrogenation and deoxidation and the breakdown of carbon chain. Further, La-Al-MCM-41 and Ce-Al-MCM-41 catalysts can produce more toluene and 2-methoxy-phenol, as compared to the non-catalytic runs.

A new kind of high-gravity device—crossflow concentric-ring rotating bed was developed, of which the rotor contains a series of perforated concentric rings. In operation, the gas could repeatedly crosscurrently make contact with the dispersed liquid flow between the concentric rings. The rotor structures and flow arrangements determine the device’s potential features, such as lower pressure drop and power consumption, which, together with the multiple-contact mechanism, are favorable to gas−liquid stripping processes. In a pilot crossflow concentric-ring rotating bed, the performance of the rotor was investigated under different operation conditions. The experimental results show that the pressure drop Δp, the power consumption P, and the mass transfer coefficient kLa fall within the range of 0.03−1.02 kPa, 0.65−1.08 kW, and 0.027−0.071 s−1, respectively. Empirical correlations based upon the experimental data were proposed to describe the dependence of pressure drop and power consumption on operation parameters. Compared with packed columns and spray contactor, the crossflow concentric-ring rotating bed has great advantages in mass transfer, equipment size, and gas/liquid loading despite the additional energy consumption. Moreover, the crossflow concentric-ring rotating bed shows lower pressure drop, power consumption, and mass transfer coefficient than that of counterflow or crossflow rotating packed beds. However, considering that stripping makes no high demand on mass transfer, crossflow concentric-ring rotating bed can be a promising option in performing stripping processes.

To overcome the disadvantages of the rotating bed available in open literature, a novel kind of high gravity device-rotating zigzag bed (RZB) was developed, which exhibits many superior features owing to its unique rotor combining a rotational part with a stationary one. The outstanding characteristics of RZB are its capability of middle-feed and easily realizing multirotor configuration in one unit by simply installing multiple rotors along the same axis. Thus one unit of RZB can be applied to continuous distillation processes with a higher mass transfer capacity. A preliminary test of mass transfer performance of the RZB in a pilot-scale system using methanol−water was carried out in this study. Experimental results show its excellent mass transfer behavior with an acceptable pressure drop. Comparison with rotating packing bed (RPB) shows that RZB provides equivalent mass transfer efficiency to RPB but exhibits excellent operability with a higher turndown ratio than that of RPB. Comparison with valve tray indicates that the baffle efficiency of RZB is slightly lower than the plate efficiency of valve tray. But if the difference between the tray space and baffle space is taken into consideration, RZB provides much higher efficiency than that of valve tray. Therefore the RZB is a kind of high efficiency gas−liquid contactor and a promising alternative in chemical process industries.

Isobaric T, x, y data were measured for the quaternary system water + ethanol + ethyl acetate + 1-butyl-3-methylimidazolium acetate at low water mole fractions and at p = 100 kPa. By a procedure presented in this work for systems composed of three volatile components and a nonvolatile ionic liquid (IL), the vapor-phase compositions were obtained by analytical methods and the liquid-phase compositions were calculated with the aid of mass balances. Activity coefficients of the volatile components were obtained without the need of a thermodynamic model of the liquid phase. Enhancement of the relative volatilities by addition of the IL was related with the effect of the IL on the activity coefficients. With the addition of the IL, the activity coefficients of water and ethanol decreased, while the activity coefficient of ethyl acetate increased. The reversed effect of the IL on the activity coefficients resulted in a consistent effect on the relative volatility. At an IL mass fraction of 0.7, the relative volatilities reach appreciable values of 14 for ethyl acetate to ethanol, 84.1 for ethyl acetate to water, and 11.3 for ethanol to water. The VLE data were correlated by the NRTL equation.

The effect of ultrasound on the leaching process, in which Geniposide is leached from the Gardenia fruit by deionized water at 20 °C, was investigated. The phase equilibrium and the dynamics were measured at static, stirring, and ultrasonically assisted conditions, respectively. The experimental results show that the extraction yield of Geniposide with ultrasound at 0.1533 W cm−2, is increased by 16.5%, in comparison with that without ultrasound when the ratio of the solvent volume to the fruit weight is 40 ml/g. A model for mass transfer, based on the intraparticle diffusion and the external mass transfer, was developed. And the dynamic curves calculated by the model are in a good agreement with the experimental data. The external mass transfer coefficient kf/R and intraparticle diffusion coefficient De/R2 were obtained by fitting of the experiment data. The external mass transfer coefficient with ultrasound at 0.1533 W cm−2 is 1.63 times higher than that in static process, and the intraparticle diffusion coefficient with ultrasound at 0.1533 W cm−2 is 3.25 times higher than that in static process.

The effects of pulse ultrasound with different pulse parameter on the adsorption isotherm and kinetics of Geniposide on Resin 1300 were studied. And the mass transfer model describing the adsorption process was constructed.Amount of Geniposide adsorbed on Resin 1300 in the presence of ultrasound is lower than that in the absence of ultrasound. At our experimental conditions, the adsorption equilibrium constant decreases with increasing ultrasonic intensity and pulse duty ratio, and with decreasing pulse period. In addition, pulse ultrasound can enhance both liquid film diffusion and intraparticle diffusion, and the intensification of liquid film diffusion with pulse ultrasound is stronger than that of intraparticle diffusion. The intraparticle diffusion coefficient De/R2 increases with increasing ultrasonic intensity and pulse duty ratio, and with decreasing pulse period.