Chemical Engineering & Technology最新文献

Using catalytic methane decomposition techniques to produce H₂ could advance renewable energy development. Selecting the proper catalyst for this method is essential for efficient hydrogen production. We used reactive molecular simulations to examine methane's decomposition reaction and the formation of H₂ molecules on a Ni (1 1 0) surface. The results show that the dissociation of H atoms on Ni (1 1 0) surfaces produced H₂ molecules. The reaction reached saturation because the Ni (1 1 0) surface was covered by methane fragments. These exhibited enhanced adsorption as the H atoms’ dissociation intensified. As the number of hydrogen atoms bonded to methane fragments decreased, the adsorption energy of methane fragments decreased.

To obtain thermodynamic and kinetic data of sodium hypophosphite, such as solubility and metastable zone, respectively, the solubility data for sodium hypophosphite in the temperature range of 298.15–373.15 K were obtained using a dynamic method. These data were then fitted to the Apelblat and Van't Hoff equations, and the corresponding model parameters were determined. The effects of stirring intensity and cooling rate on the width of the metastable zone of sodium hypophosphite in water were studied. The findings indicated that an increase in stirring intensity reduced the width of the metastable zone, whereas an increase in cooling rate resulted in its widening. The self-consistent NýVlt and Sangwal metastable zone models were employed to calculate nucleation dynamic parameters in conjunction with classical nucleation theory. The results showed that the nucleation order was 2.311–3.361 over the investigated temperature range. 316.15 K is the critical temperature point at which sodium hypophosphite transforms into a dominant nucleation mode. The solid–liquid interface tension decreased rapidly with the increase of saturation temperature, and the solid–liquid interface tension is 1.167–2.638 mJ m⁻².

Utilizing pressure as a process parameter can make biotechnological processes more efficient and attractive compared to established ones. This paper presents a high-pressure reactor setup for enzymatically catalyzed gas–liquid reactions, which can be operated up to 15.0 MPa. The reactor is equipped with optical measurement technology for inline and in situ monitoring of the oxygen concentration under high-pressure conditions. The setup is characterized by assessing the influence of the process parameter pressure on the conversion of the glucose oxidation to d-glucono-δ-lactone by immobilized glucose oxidase. The study demonstrates that the increased oxygen availability due to higher solubility reduces the reaction time in a batch reactor from 270 to 90 min.

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Carbon capture utilization and storage-enhanced oil recovery (EOR) is often considered the most promising technology for utilizing CO₂. Cryogenic distillation is also viewed as the most reasonable separation option for handling CO₂-EOR gases, despite being an energy-intensive process. The main challenge for this technology is energy loss. To overcome this challenge, one potential alternative is to optimize the system processes and parameters. This study proposes a new process to reduce distillation energy consumption by refluxing the distillate back to the distillation column. Operational parameter optimization was performed using the commercial simulator Aspen HYSYS for modeling and sensitivity analysis of process parameters using orthogonal experimental methods. The simulation results indicate that after optimization, the energy consumption in the distillation process decreased from 0.207 to 0.196 MJ kg⁻¹, whereas the purity decreased slightly from 94.63 % to 94.52 %. However, the recovery increased from 97.8 % to 97.88 %, and the total energy consumption decreased from 0.772 to 0.761 MJ kg⁻¹.

In order to understand the effect of different tube structures on the heat transfer characteristics of supercritical CO₂ in heating serpentine micro-tubes, five structures are investigated. At the same inlet Reynolds number, because the periodic disturbance frequency of boundary layer and centrifugal force decrease with the increase of curvature radius and the boundary layer thickens with the increase of tube diameter, the comprehensive heat transfer performance of serpentine micro-tubes decreases with the increase of curvature radius and tube diameter. Gravitational buoyancy is independent of curvature radius but increases with the increase of tube diameter. Centrifugal force and centrifugal buoyancy decrease with the increase of curvature radius and tube diameter.

Solid-state fermentation (SSF) has gained considerable attention due to its potential in the production of bioactive compounds from agroindustrial residues, aligning with circular economy targets. This review examines the core bases involved in SSF with a focus on bioreactor engineering. The review underlines the microorganisms metabolic activities under different operational conditions and focuses on engineering challenges encountered in designing packed-bed bioreactors, including an analysis of the interaction between microbial growth kinetics and transport phenomena. Finally, given its essential role in the scaling-up process, this review discusses mathematical modeling developed for SSF in packed-bed bioreactors, establishing a foundation for the future development of more efficient, scalable, and sustainable SSF-based applications.

In this study, the activated carbon (AC) was prepared from Sesbania sesban plant stem. Boric acid (H₃BO₃) was used as an activating agent. During calcination, the optimized temperature was kept upto 500 °C for 2 h. The prepared adsorbents were characterized using various techniques such as FT-IR, scanning electron microscopy, energy dispersive x-ray spectroscopy, and thermogravimetric analyzer. The prepared adsorbents were used for the removal of methylene blue (MB) dye adsorption. The adsorption experiments were conducted at different pHs such as (2–11), doses (0.0025–0.020 mg), times (30–300 min), MB initial concentrations (100–600 mg L⁻¹), and temperatures (298–318 K), respectively. The maximum MB uptake capacity of the prepared adsorbent was 1380 mg g⁻¹ under optimized adsorption conditions. Furthermore, the kinetic study is well described by pseudo-second order, whereas the isothermal study showed the Freundlich isotherm was better followed by the equilibrium data. Based on thermodynamic studies, the negative values of ΔG° and ΔH° revealed that the MB adsorption process is spontaneous and exothermic in nature. However, the negative ∆Sxg° value indicates that solid-solute interaction decreased randomness in the adsorption systems. The overall studies of AC showed that it was better to remove MB from an aqueous solution.