[en] Specific features of calcium-thermic reduction of UF₄ in a water-cooled plant are under consideration. Plant design is schematically represented and processing procedures for metallic uranium castings production are described. A particular attention is paid to service life of the basic part of the plant, namely, of reaction water cooled chromium bronze tube. 2 refs., 1 fig

[en] Hydrogen-producing granules formation was studied in a Continuos Stirred Tank Reactor (CSTR). The aim of this process is to later transfer the mixed liquor to a Up-flow Anaerobic Sludge Blanket (UASB) reactor to reduce its start-up period. Vinasses from a national bioethanol-producing industry (from sugar cane) were used as substrate and their anaerobic fermentation was carried out under mesophilic conditions. The seed sludge was collected from an UASB reactor operated in an industrial wastewater treatment plant and it was heat treated to inactivate methanogenic bacteria. Total viable and non-viable material growth curves were generated and it was determined that the exponential growth phase of the thermally pretreated mixed culture was between 20 and 120 h. Finally, the anaerobic fermentation of the vinasses in batch mode for 70 hours, and then in continuous CSTR mode for 7 days, showed to be an effective method for accelerating the formation of hydrogen-producing granules. Using this method, granules with an average size of 1.24 mm were achieved. The good efficiency of the process is attributed to high mass transfer in the CSTR reactor (author)

No abstract available

[en] The design inadequacy of chemical reactor has caused many major accidents in process industries. The absence of safety analysis for chemical reactor especially in the early design stage is one of the reasons for faulty designs. Inherent safety can be used to perform the safety analysis at preliminary design phases. However, the literature is deficient in reporting inherent safety assessment method for chemical reactors. Therefore, this paper introduces a new indexing method for inherently safety assessment of chemical reactors at the preliminary design stage. Chemical Reactors Inherent Safety Index (CRISI) is based on three sub-indices; chemical index, process index and reaction index. These sub-indices are estimated through scores of numerous parameters in each dimension. For the unacceptable score, the process conditions are changed according to the favorable reaction conditions. CRISI is estimated for all combination of process conditions and lowest CRISI value indicates the inherently safer design of the reactor. (paper)

[en] This is a topical report of the NERI project ''An Innovative Reactor Analysis Methodology Based on a Quasidiffusion Nodal Core Model''

[en] A physical analogue of a continuous flow and well stirred chemical reactor was designed,constructed and operated in our laboratory.An instantaneous injection of Uranine was used as tracer for measuring its residence time distribution.A non-linear functional was used to fit the experimental data.Its parameters were optimised for maximum likelihood,employing computational techniques developed in our centre.The problem of using the minimum amount of parameters without lowering the likelihood of the fitting was appraised.In was done considering the physical meaning of the selected models.Four models were implemented using plug flows and well mixed compartments with feed forward and feedback flow paths.other important experimental topics,as well mixing problems of the tracer are discussed in the paper

[en] A gas-liquid microfluidic reactor was used to prepare polymer nanoparticles (PNPs) containing the drug 7-ethyl-10- hydroxy camptothecin (SN-38) from a series of poly(methyl caprolactone-co-caprolactone)-b-poly(ethylene oxide) (P(MCL-co-CL)- b-PEO) amphiphilic block copolymers with variable MCL content in the hydrophobic block. All three copolymers formed spheres with 20 nm core diameters by TEM, although some rigid rod-like aggregates were also formed by the PMCL-50 and PMCL-75 copolymers. SN-38 encapsulation efficiencies (EE = 2.7%-3.0%) and loading levels (DL = 2.0%-2.9%) were similar for the three copolymers. In vitro release kinetics became significantly slower as the MCL content increased, with release half times increasing monotonically from 3.4 to 6.2 h as the MCL content of the hydrophobic block increased from 50% to 100%. The ability to systematically tune release half times via controlled variation in the hydrophobic block composition, while maintaining constant PNP size and loading levels, represents an intriguing chemical handle for the optimization of SN-38 nanomedicines. (author)

[en] Liquefying of pulverulent batch materials (e.g., glass batch) is carried out in two stages. The first stage utilizes extended gas/solid contact to heat the materials to an intermediate temperature, and may recover waste heat. The second stage rapidly liquefies the material in a cavity lined with the batch material, and may employ substantially nitrogen-free heat sources. Another aspect involves maintaining a wet condition in the first stage to entrap particulates

[en] Modeling is an important tool to study and evaluate the behavior of the chemical process. Combination of simulation and control, it exhibits various characteristics of the process and provides the right direction to obtain the desired results from the chemical reactors. This paper discusses the various technical aspects of modeling, simulation and control in the process industries. The utilization and the relationship among the three techniques, modeling, simulation and control have been discussed. A case study is then presented for a batch reactor (in a sugar manufacturing plant) to use the modern techniques for modeling, simulation and instrumentation control. Presenting various scenarios on the above discussed techniques, the task has been dealt with comprehensively. (author)

[en] Compared with large-scale processes, the LiFePO₄ (LFP) melt-synthesis is a low-cost method with short dwell times and rapid reaction rates. However, secondary phases and impurities remaining in the olivine structure lower the cathode's electrochemical properties. Starting from a low-cost Fe³⁺ precursor, we evaluated tin and silver charged metallic baths to purify the melt-synthesis of LiFePO₄ at laboratory scale. In the tin bath exploration, an x-ray diffraction (XRD) confirmed the olivine structure and a temperature-dependent generation of Li₃PO₄ and Li₄P₂O₇. An SEM image analysis identified tin-rich phases (Sn_xP_yO_z) segregated from the LFP structure and Fe_xP phases on the internal walls of the crucible. A multi-element analysis (ICP-AES) detected more than 0.03 g of Sn/g of LFP. The tin bath prepared samples delivered up to 156 mAh/g of LFP in a carbon-free basis, 3 % lower than the capacity of the high purity Fe₂O₃-based material at 0.1 C. The silver bath-based LFP samples produced cleaner XRD patterns (less than 160 ppm of Ag in the LFP ingots), closer to the estimated molar ratios and neither silver compounds nor silver oxides. In this case, the sample delivered 161 mAh/g of LFP, the same capacity as the cathode prepared without a metallic bath. Starting from a commodity Fe³⁺ source, future work should explore the silver bath roles as a reactive media, a heating source, a crucible insulator, and a potential contaminant trap for the melt-synthesis of LiFePO₄. (author)