Solubility Measurement for the Reaction Systems in Pre-Esterification of High Acid Value <i>Jatropha curcas</i> L. Oil

Crude Jatropha curcas L. oil (Oil) normally contains some free fatty acids (FFAs), and it must be pre-esterified with methanol before it is used as the feedstock of the transesterification operation in biodiesel production. The mutual solubility of the pre-esterification reaction mixture was measured over the reaction temperature range from (303.1 to 333.1) K. The phase diagrams included the ternary diagrams of FFA + oil + methanol, FFA + methanol + water, Jatropha curcas L. oil methyl ester (FAME) + methanol + water, and FAME + methanol + oil. The data show that the mutual solubility increases with temperature. High FFA content can increase the mutual solubility of methanol and oil. The products, namely, water and FAME, change the distribution of oil and methanol

Modeling of cavity nucleation, early‐stage growth, and sintering in polycrystal under creep–fatigue interaction

A mechanistic-based cavitation model that considers nucleation, early-stage growth, and sintering under creep–fatigue interaction is proposed to predict the number density of cavities ρ. Both the nucleation and early-stage growth rates, controlled by grain boundary (GB) sliding under tension, are formulized as a function of local normal stress σn. Cavity sintering that occurs during the compression is governed by the unconstrained GB diffusion depending on the σn. Modeling results provide important insights into experimental load-waveform design. First, test with initial compression promotes higher ρ compared to the initial tension, if the unbalanced hold time in favor of tension is satisfied. Second, the ρ value does not have a monotonic dependence on either the compressive hold time or stress, because of their competing effect on nucleation and sintering. Third, the optimum value of stress variation rate exists in terms of obtaining the highest ρ value due to sintering effect

Modeling of cavity nucleation, early‐stage growth, and sintering in polycrystal under creep–fatigue interaction

A mechanistic-based cavitation model that considers nucleation, early-stage growth, and sintering under creep–fatigue interaction is proposed to predict the number density of cavities ρ. Both the nucleation and early-stage growth rates, controlled by grain boundary (GB) sliding under tension, are formulized as a function of local normal stress σn. Cavity sintering that occurs during the compression is governed by the unconstrained GB diffusion depending on the σn. Modeling results provide important insights into experimental load-waveform design. First, test with initial compression promotes higher ρ compared to the initial tension, if the unbalanced hold time in favor of tension is satisfied. Second, the ρ value does not have a monotonic dependence on either the compressive hold time or stress, because of their competing effect on nucleation and sintering. Third, the optimum value of stress variation rate exists in terms of obtaining the highest ρ value due to sintering effect

Active Oxygen Vacancy Site for Methanol Synthesis from CO₂ Hydrogenation on In₂O₃(110): A DFT Study

Methanol synthesis from CO₂ hydrogenation on the defective In₂O₃(110) surface with surface oxygen vacancies has been investigated using periodic density functional theory calculations. The relative stabilities of six possible surface oxygen vacancies numbered from O_v1 to O_v6 on the perfect In₂O₃(110) surface were examined. The calculated oxygen vacancy formation energies show that the D1 surface with the O_v1 defective site is the most thermodynamically favorable while the D4 surface with the O_v4 defective site is the least stable. Two different methanol synthesis routes from CO₂ hydrogenation over both D1 and D4 surfaces were studied, and the D4 surface was found to be more favorable for CO₂ activation and hydrogenation. On the D4 surface, one of the O atoms of the CO₂ molecule fills in the O_v4 site upon adsorption. Hydrogenation of CO₂ to HCOO on the D4 surface is both thermodynamically and kinetically favorable. Further hydrogenation of HCOO involves both forming the C–H bond and breaking the C–O bond, resulting in H₂CO and hydroxyl. The HCOO hydrogenation is slightly endothermic with an activation barrier of 0.57 eV. A high barrier of 1.14 eV for the hydrogenation of H₂CO to H₃CO indicates that this step is the rate-limiting step in the methanol synthesis on the defective In₂O₃(110) surface

Preparation of Oriented Superhydrophobic Surface to Reduce Agglomeration in Preparing Melt Marbles

Numerous innovative granulation techniques utilizing the concept of liquid marbles have been proposed before. However, these processes frequently encounter issues such as collisions, aggregation, and fragmentation of liquid/melt marble during the granulation process. In this study, the oriented superhydrophobic surface (OSS) was successfully prepared by utilizing copper wire to solve the above problem, facilitating efficient batch production and guided transportation of uniform marbles. The parameters and mechanisms of this process were thoroughly studied. The optimized structure is that the copper wire spacing (d) and height (h) are set as 1.0 and 0.1 mm, respectively. This resulted in a surface contact angle (CA) of 156° and anisotropic sliding (ΔSA) of 16.3 ± 1.34°. Using the prepared substrate, high-quality urea products were successfully obtained through the controlled transport of urea melt marbles. The mechanism of guided and directional drag reduction, based on the solid/solid contact on the surface, is proposed. These findings in this study have significant implications for improving granulation processes

Preparation of Oriented Superhydrophobic Surface to Reduce Agglomeration in Preparing Melt Marbles

Numerous innovative granulation techniques utilizing the concept of liquid marbles have been proposed before. However, these processes frequently encounter issues such as collisions, aggregation, and fragmentation of liquid/melt marble during the granulation process. In this study, the oriented superhydrophobic surface (OSS) was successfully prepared by utilizing copper wire to solve the above problem, facilitating efficient batch production and guided transportation of uniform marbles. The parameters and mechanisms of this process were thoroughly studied. The optimized structure is that the copper wire spacing (d) and height (h) are set as 1.0 and 0.1 mm, respectively. This resulted in a surface contact angle (CA) of 156° and anisotropic sliding (ΔSA) of 16.3 ± 1.34°. Using the prepared substrate, high-quality urea products were successfully obtained through the controlled transport of urea melt marbles. The mechanism of guided and directional drag reduction, based on the solid/solid contact on the surface, is proposed. These findings in this study have significant implications for improving granulation processes

Preparation of Phase Change Melt Marbles with High Thermal Stability by Spontaneous Shrinkage and Encapsulation

Liquid marbles (LMs) are widely used in the fields of microfluids, gas sensitivity equipment, and microreactors. However, the thermal stability of the encapsulated liquid poses difficulty to the high-temperature stability of LMs. In this study, polar phase-change materials (PCMs) with high melting points were used as the encapsulated liquid of LMs. According to the required temperature, suitable PCMs were selected as the core and encapsulated by hydrophobic SiO2 particles to form melt marbles (MMs). The types of PCMs used to prepare the MMs include erythritol, elemental sulfur, urea, and molten salts. Based on the premixed melting method, a series of MMs with high melting points and thermal stability were successfully developed. The highest acceptable temperature of the MMs exceeded 323 °C, and the evaporation rate of erythritol MMs was less than 1% at 140 °C in 8 h. Thus, the MMs maintained their excellent stability through multiple phase transitions. In the molten state, the MMs exhibited the properties of bounce ability, cuttability, and deformation resistance. The performance of the PCMs in energy storage and release during phase transition demonstrates their potential applications in the field of heat storage

Preparation of Phase Change Melt Marbles with High Thermal Stability by Spontaneous Shrinkage and Encapsulation

Liquid marbles (LMs) are widely used in the fields of microfluids, gas sensitivity equipment, and microreactors. However, the thermal stability of the encapsulated liquid poses difficulty to the high-temperature stability of LMs. In this study, polar phase-change materials (PCMs) with high melting points were used as the encapsulated liquid of LMs. According to the required temperature, suitable PCMs were selected as the core and encapsulated by hydrophobic SiO2 particles to form melt marbles (MMs). The types of PCMs used to prepare the MMs include erythritol, elemental sulfur, urea, and molten salts. Based on the premixed melting method, a series of MMs with high melting points and thermal stability were successfully developed. The highest acceptable temperature of the MMs exceeded 323 °C, and the evaporation rate of erythritol MMs was less than 1% at 140 °C in 8 h. Thus, the MMs maintained their excellent stability through multiple phase transitions. In the molten state, the MMs exhibited the properties of bounce ability, cuttability, and deformation resistance. The performance of the PCMs in energy storage and release during phase transition demonstrates their potential applications in the field of heat storage

Ultralow Adhesion and Phase Change Behaviors of Sulfur Droplets on the Superhydrophobic Surface and Its Application in the Granulation Process

Traditional sulfur granulation process is often accompanied by high dust and mechanical friction, which are dangerous and harmful to the environment. In this work, the application of the superhydrophobic surface to sulfur granulation is expected to solve the above problem. Two superhydrophobic metal sheets were prepared, and the rolling angles of the two samples are both less than 10°. The contact angles of liquid sulfur are 152.7 ± 0.5 and 151.3 ± 0.1°, respectively. The adhesion rates of both samples are less than 0.5 wt %. The solidifying process of a sulfur drop on the superhydrophobic surface was recorded and simulated, conforming that the substrate temperature has a great influence on the solidifying process. Based on the above findings, static granulation and rolling to granulation were proposed. The product obtained by the two methods has uniform particle size distribution and excellent compressive strength, showing a good industrial application prospect. This study provides a referral strategy for an economical and environmentally friendly sulfur granulation process

Ultralow Adhesion and Phase Change Behaviors of Sulfur Droplets on the Superhydrophobic Surface and Its Application in the Granulation Process

Traditional sulfur granulation process is often accompanied by high dust and mechanical friction, which are dangerous and harmful to the environment. In this work, the application of the superhydrophobic surface to sulfur granulation is expected to solve the above problem. Two superhydrophobic metal sheets were prepared, and the rolling angles of the two samples are both less than 10°. The contact angles of liquid sulfur are 152.7 ± 0.5 and 151.3 ± 0.1°, respectively. The adhesion rates of both samples are less than 0.5 wt %. The solidifying process of a sulfur drop on the superhydrophobic surface was recorded and simulated, conforming that the substrate temperature has a great influence on the solidifying process. Based on the above findings, static granulation and rolling to granulation were proposed. The product obtained by the two methods has uniform particle size distribution and excellent compressive strength, showing a good industrial application prospect. This study provides a referral strategy for an economical and environmentally friendly sulfur granulation process