Chemical Engineering & Technology最新文献

Bioreactor for microbiology. Copyright: Grispb ©stock.adobe.com

Selective laser melting can be used to create custom-made monolith reactor components with embedded microscale catalytic sites. Doping with noble metals (0.01–0.04 % of Pt, Ir, Ru, or Rh) gave clean incorporation of the active metal particles metals. Yet catalytic activity was low, due to distribution of the active particles between the surface and the bulk of the monolith. Switching to cobalt enabled doping in higher amounts (1.5–2.0 %) with corresponding increase in activity. Using borohydride hydrolysis as a test reaction, we showed that a combined stainless steel and cobalt monolith was active in both batch and continuous systems, for at least 48 h, albeit with some loss of active material. The advantages and limitations of this catalyst/reactor preparation method are discussed.

In this paper, granular flow is studied using particle image velocimetry (PIV) in two different geometries, that is, rectangular box and cylindrical bladed mixer. Effects of parameters like blade rake angle, bed height, moisture content, and the number of blades were studied. The shear rate and velocity magnitude of granular bed were calculated using PIV. The presence of moisture in the granular bed added additional cohesive forces and reduced shear rate between different layers of particles. Shear rate and shear forces were maximal at the tip of the blade. Temperature variations in the granular bed were measured experimentally and results were compared for static and mixing beds.

Predicting the productivity of the freeze desalination process is of key importance. This paper describes an analytical method to predict the productivity for the progressive freeze desalination process utilizing the rectangular channel crystallizer design. The mass of ice produced during the process is considered a measure of productivity. The model was developed using heat and mass transfer modeling. The effect of coolant temperature (from −8 to −16 °C), liquid flow rate (4400–6000 mL min⁻¹), and initial salt concentration of the liquid (1.5–7 wt%) on the mass of ice produced was investigated. The analytical results of the mass of ice produced were compared with the experimental data. A plausible match was found between the analytical and experimental results, with an error range between 6 % and 9 %. The model can predict the mass of ice produced for given values of the initial salt concentration of the liquid, initial mass of the liquid, salt concentration of thawed ice, liquid flow rate, and coolant temperature.

This review presents the technical and operational performances of solar and biomass energy technologies viz photovoltaic thermal (PVT) and biomass gasification systems. This work aims to offer a reference and guidelines to the renewable energy-related players, especially for those at the operational level and investors. This paper highlights the technical advantage of hybrid PVT with phase change material in terms of electrical and thermal efficiencies. While the operational performance of biomass gasification is thoroughly discussed via sensitivity analysis, the potential integration between solar and biomass gasification technologies is explored to complement and bolster the capabilities of both renewable systems within the power energy mix portfolio. Finally, few directions and significant takeaways considering the technical criteria are addressed for identifying efficient renewable energy generation.

The present study contributes to overcoming the serious drawback of the traditional stirred slurry catalytic reactor, namely, the costly and time-consuming separation of the catalyst particles from the final product using a stationary fixed bed of Raschig rings placed above a rotating impeller. The rate of diffusion-controlled reactions was measured in terms of the mass transfer coefficient under different conditions of impeller rotation speed, Raschig ring diameter, and bed height. The rate of mass transfer was determined by a technique which involves measuring the rate of diffusion-controlled dissolution of copper in acidified dichromate. The data were correlated by a dimensionless correlation which can be used to scale up and design the reactor. The reactor performance was measured in terms of the mass transfer coefficient and the energy utilization efficiency. Possible applications of the reactor in conducting diffusion-controlled reactions were highlighted.

Continuous crystallization of pharmaceuticals has been in the center of attention during the past two decades, with a more focus on the large-scale production of active pharmaceutical ingredients. The increasing demand for pharmaceuticals requires high-throughput production of drug crystals with different solubilities, stabilities, shapes, habits, polymorphs, and size distributions. With numerous advantages including low cost, ease of scale-up, and superior control over polymorph and size distribution of drug crystals, antisolvent crystallization is one of the most promising crystallization methods recently attempted. However, it fails to deliver the required characteristic where the crystal systems tend to grow and for the preparation of metastable polymorphs. This review focuses on the most recent efforts to tackle these drawbacks by coupling antisolvent crystallization with cooling, supercritical-assisted, microfluidics-assisted, and membrane-assisted crystallization. This systematic review aims to provide a concise summary of each coupled antisolvent technique and their positive and negative aspects. This review can be used as a guideline for pharmacist, biologists, and chemists, who are interested in the crystal engineering of pharmaceuticals to pave the way for further developments in this field.

The column performance of silica-coated, amino-functionalized, superparamagnetic nanoparticles co-integrated with Cynodon dactylon and Murraya koenigii plant extracts for the removal of Cu^II ions was evaluated. The co-integrated nanoparticles were used as sorbent materials in fixed-bed column studies, and the effects of inlet concentration, adsorbent bed depth, and flow rate were analyzed. Breakthrough time was calculated for various Cu^II inlet concentrations, depths of the adsorbent bed, and volumetric flow rates. Models such as Thomas, Yoon-Nelson, and the bed depth model were evaluated to determine the experimental fit. The maximum breakthrough time for Cu^II ions of 1200 min was attained for a Cu^II inlet concentration of 100 mg L^–1, sorbent bed depth of 3 cm, and volumetric flow rate of 1 mL min^–1.