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Pyrolysis of methyl ricinoleate (MR) can produce undecylenic acid methyl ester and heptanal which are important chemicals. Atomization feeding favors the heat exchange in the pyrolysis process and hence increases the product yield. Herein, predictive models to characterize the atomization process were developed. The effect of spray distance on Sauter mean diameter (SMD) of atomized MR droplets was examined, with the optimal spray distance to be 40–50 mm. Temperature mainly affected the physical properties of feedstock, with smaller droplet size obtained at increasing temperature. In addition, pressure had significant influence on SMD and higher pressure resulted in smaller atomized droplets. Then, a model for SMD prediction, combining temperature, pressure, spray distance, and structural parameters of nozzle, was developed through dimensionless analysis. The results showed that SMD was a power function of Reynolds number (Re), Ohnesorge number (Oh), and the ratio of spray distance to diameter of swirl chamber in the nozzle (H/dsc), with the exponents of − 1.6618, − 1.3205 and 0.1038, respectively. The experimental measured SMD was in good agreement with the calculated values, with the error within ± 15%. Moreover, the droplet size distribution was studied by establishing the relationship between the standard deviation of droplet size and SMD. This study could provide reference to the regulation and optimization of the atomization process in MR pyrolysis.

Desulfurization is important to the enhancement of biodiesel quality. In this study, the effects of reactant and catalyst addition and operations conducted on sulfur content at each stage during the biodiesel preparation process were examined. Based on the results of sulfide qualification and quantification, a high vacuum distillation method was developed to remove the sulfides in crude biodiesel. Biodiesel was separated into different fractions based on the boiling point and the sulfur content of each fraction was determined. Experimental results showed that most sulfides were distilled out with light and heavy fractions. Intermediate fraction was separated from the other fractions, resulting in high quality biodiesel with low sulfur content. The total yield of distillation fractions with sulfur content lower than 10 ppm reached 84.1%. A set of distillation facility with capacity of 10 m3/h was designed and developed accordingly for large-scale tests. The yield of low-sulfur biodiesel was around 83%, close to that obtained in the laboratory studies. In addition, economic analysis showed that the distillation facility can make revenue of more than $1.8 million per year, indicating that high vacuum distillation is economically feasible and promising for biodiesel desulfurization, especially in industrial application.

A stable high-temperature reaction site and the rapid and uniform heating of the feedstocks are particularly important in pyrolysis. A novel device consisting of microwave-assisted heating (MAH) coupled with atomization feeding was used for continuous pyrolysis of methyl ricinoleate (MR) using silicon carbide (SiC) as the microwave absorbent bed. The heat transfer in microwave heating and MR pyrolysis in MAH device was studied by three-dimensional simulation. The effects of number of ports and heating power in microwave heating process, flow rate, feed mode and average droplet diameter of MR in pyrolysis process were investigated. Uniform temperature distribution of SiC bed surface was obtained with different numbers of ports. Higher energy efficiency was obtained at higher microwave power, with the highest value reaching 81% at 1000 W. The maximum flow rate of MR could reach 40 mL/min at a stable high-temperature bed surface. The atomization feed mode was beneficial to the temperature uniformity of SiC bed. The heating rate of atomized MR droplets was about 50000 °C/s, significantly higher than that of dropped MR droplets. The simulated results agreed well with the experimental results. It indicated the MAH coupled with atomization feeding could provide a stable high-temperature reaction site and increase the rapid and uniform heating of the feedstocks.

The solubilities of sulfuryl fluoride (SO2F2) in propylene carbonate (PC), tributyl phosphate (TBP) and N-methylpyrrolidone (NMP) was measured by isochoric saturation method at the pressure of up to 600 kPa and temperatures ranging from (293.15 to 313.15) K. Results showed that SO2F2 solubility increased with increasing pressure and decreased with increasing temperature in the three solvents, and the dissolution of SO2F2 in the solvents was a physical process. Moreover, Henry’s law constants and thermodynamic properties such as standard Gibbs free energy, enthalpy, and entropy changes of SO2F2 solvation were further calculated according to the experimental solubility data. The solubility of SO2F2 in these three solvents followed the order of TBP > PC > NMP. The results illustrated that TBP possessed the potentiality to capture SO2F2 among the present absorbents due to the relatively large solubility and low absorption enthalpy for SO2F2.

A large amount of sulfuryl fluoride (SO2F2) is released into the atmosphere after fumigation, intensifying the greenhouse effect. Therefore, it is important to remove SO2F2 generated in fumigation. In this study, the solubilities of SO2F2 in 2-butoxyethyl acetate (BOEA), 3-methoxybutyl acetate (MOBA), 2-methoxyethyl acetate (MOEA), 1-methoxy-2-propyl acetate (MOPA), and 2-(2-ethoxyethoxy)ethyl acetate (DEOEA) were determined at T = (293.15 to 323.15) K and pressures up to about 600 kPa using the isochoric saturation method. Results showed that SO2F2 solubility in the five acetate derivatives increased with increasing pressure and decreased with increasing temperature. The dissolution of SO2F2 in these solvents belonged to a physical process. Furthermore, the Henry’s law constants and thermodynamic properties including standard Gibbs free energy, enthalpy, and entropy changes of SO2F2 dissolution were further obtained. Compared with water, these five selected acetate derivatives showed potential applicatio...

Undecylenic acid methyl ester (UAME) and heptanal (HEP) are important chemical intermediates, which can be produced from pyrolysis of methyl ricinoleate (MR). The temperature gradient existing in conventional tubular reactor for MR pyrolysis would cause the reduction of UAME and HEP yields. An inductively heated reactor coupled with atomization feeding was developed in this study and used for MR pyrolysis. Numerical simulation was first adopted to examine the effect of nozzle number on temperature distribution of the reactor. Results showed that uniform temperature distribution was achieved when three nozzles were used. The average temperature and the standard deviation of the reaction area were 496.54 °C and 6.34 °C respectively at the set temperature of 500 °C. Experimental tests of MR pyrolysis on the reactor were then performed using three nozzles. Results showed that MR conversion increased with the increasing temperature from 440 to 560 °C. The highest UAME and HEP yields of 56.1 wt% and 60.2 wt% respectively were achieved at 520 °C. The product yields were obviously higher than those obtained using conventional tubular reactor. It was mainly due to the uniform temperature distribution of reactor and rapid heating of feedstock by using the inductively heated reactor coupled with atomization feeding.

The degradation of methylene blue (MB) using a novel dielectric barrier discharge plasma reactor coupled with activated carbon supported polyurethane foam (AC/PUF) was investigated in this paper. The plasma reactor combining a glass bead-packed bed and a microporous plate was developed. The AC/PUF provided sufficient contact area between carbon media and pollutants and hence revealed a good MB removal capacity. The effects of input voltage and initial MB solution concentration on MB degradation efficiency were examined. Kinetic study indicated that plasma and AC/PUF in the coupled system had a good synergistic effect in MB degradation. The degradation efficiency of 100 ppm MB solution could reach 97.9% with 10 min treatment in the coupled system, which was close to that obtained by plasma treatment alone for 30 min (97.5%). The COD removal in the plasma and AC/PUF coupled system (90.7%) was much higher than that obtained by plasma treatment followed by AC/PUF adsorption (58.3%). In addition, the energy yield (G50) of the coupled system was up to 38.3 g kW−1 h−1, suggesting great energy efficiency of the system. Moreover, repeated use experiments of AC/PUF showed the good utilization potential of the coupled system. Finally, a possible degradation pathway of MB was proposed.

The solubility of sulfuryl fluoride in water was experimentally measured over the pressure from P = (0 to 600) kPa and T = (283.15 to 308.15) K using isochoric saturation method. Results show that SO2F2 solubility increases with increasing pressure and decreases with increasing temperature. Using the experimental solubility data, Henry’s law constants and the thermodynamic properties such as the standard Gibbs free energy, enthalpy, and entropy changes of SO2F2 solvation were obtained. Henry’s law constant based on mole fraction and molality of SO2F2 in water vary from (432.21 to 1052.96) MPa and (7.78 to 18.96) MPa at T = (283.15 to 308.15) K, respectively.

The degradation of methylene blue (MB) using an upgraded dielectric barrier discharge (DBD) plasma reactor was investigated in this paper. Air plasma was generated in the glass bead packed bed in the reactor, which was propagated into MB solution through a microporous diffuser plate. Microdischarge phenomenon can be observed on the interface of MB solution and the diffuser plate, where plasma active species were generated. The effects of air flow rate, initial solution concentration, initial solution pH, and initial solution conductivity on MB degradation were examined. Experimental results indicated that the proposed plasma reactor was effective for MB degradation. No obvious change in MB degradation efficiency was obtained for solution with various initial pH and conductivities, which suggested the potential of the reactor in actual wastewater treatment. The possible mechanism of the generation of plasma active species for MB degradation was proposed. In addition, the total organic carbon removal and chemical oxidation demand removal after 30 min treatment were 38.5% and 48.3%, which was higher than that obtained by ozone. The energy yield for MB degradation reached up to 9.3 g/kWh. Finally, a possible degradation pathway of MB solution was proposed.