Modelling of a liquid fluidized bed separator using 1D segregation-dispersion model under continuous process conditions

Succinic acid is a biomass-derived platform chemical that can be catalytically converted in the aqueous phase to 1,4-butanediol (BDO), a prevalent building block used in the polymer and chemical industries. Despite significant interest, limited work has been reported regarding sustained catalyst performance and stability under continuous aqueous-phase process conditions. As such, this work examines Ru-Sn on activated carbon (AC) for the aqueous-phase conversion of succinic acid to BDO under batch and flow reactor conditions. Initially, powder Ru-Sn catalysts were screened to determine the most effective bimetallic ratio and provide a comparison to other monometallic (Pd, Pt, Ru) and bimetallic (Pt-Sn, Pd-Re) catalysts. Batch reactor tests determined that a ∼1:1 metal weight ratio of Ru to Sn was effective for producing BDO in high yields, with complete conversion resulting in 82% molar yield. Characterization of the fresh Ru-Sn catalyst suggests that the sequential loading method results in Ru sites that ...

On the basis of experimental data obtained from copolymer systems composed of donor, acceptor and neutral monomers the copolymerization behaviour as a function of the conversion degree was derived. The heterogeneity of the composition was calculated for experiments carried out under discontinuous process conditions (batch reactor). The influence of the reaction conditions on the chemical polydispersity was investigated in connection with continuous process conditions. The effects of incomplete micromixing on free radical copolymerization processes are presented and discussed by model calculations.

In this study, a 2D segregation-dispersion model has been used to study the effect of shear induced lift on elutriation within a Reflux Classifier under continuous process conditions. The Reflux Classifier is a beneficiating technology comprising a fluidized bed with a set of parallel inclined channels above it. A 2D segregation-dispersion model of the device was utilized to study the mechanism of shear induced lift introduced as a contribution to the dispersion in the x-direction within the inclined channel. A multi-solid feed, 42 types of particle species having different densities and sizes, was simulated. It was observed that due to the shear induced lift, a phenomenon of particle resuspension occurred causing relatively higher solid volume fractions in the middle zone of the inclined channel. This happened because the coarse low-density particles experienced a higher shear induced lift and their concentration increased toward the middle zone. These coarse low-density particles and fine low-density particles moved out from the system via the overflow. Whereas, the fine dense particles experienced a low shear induced lift, hence, settled, slide backward, and discharged in the underflow. The lower Ep values ranging from 0.03 to 0.05 were obtained showing an improved separation performance.

Cu(II) complexes as catalyst precursors in the process of selective hydrogenation of diene hydrocarbons

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Application of a 2D segregation-dispersion model to describe binary and multi-component size classification in a Reflux Classifier

Simulations of mono-sized solid particles in the reflux classifier under continuous process conditions

The paper reviews a current state of the art in the in-line plasma treatment of low-cost materials and opportunities for the use of the so-called Diffuse Coplanar Surface Dielectric Barrier Discharge (DCSBD). A brief outline of physical mechanism and basic properties of DCSBD is given. The results presented on the ambient air plasma treatments of textile, paper, wood, and glass illustrate that DCSBD offers outstanding performance with extremely low energy consumption for large area, uniform surface modifications of materials under continuous process conditions.

Bridging the bridge—Stabilization of CalB against H2O2 and its application in epoxidation reactions

Amines alkylation with alcohols catalyzed by γ-Al2O3-supported nickel and copper nanoparticles under continuous process conditions at atmospheric hydrogen pressure and 180-220°С leads to the formation of alkylated products with selectivity up to 100%.

1. Adsorption isotherms have been measured for mixed C10-C18 paraffinic hydrocarbons and n-tridecane on binder-free MgA zeolite. Commonality has been established for the adsorption characteristics of mixed C10C18 paraffins and those of an individual hydrocarbon (n-tridecane) with a molecular weight close to the average for the mixture. Thus, the adsorption isotherm of the appropriate individual hydrocarbon can be used to estimate the adsorption of multicomponent mixtures. 2. A study has been made of the influence of adsorbent circulation rate and feedstock linear velocity on the process indices in the continuous separation of n-paraffins from petroleum fractions. It has been shown that, under continuous process conditions, thorough extraction of mixed n-paraffins can be achieved. Recommendations are given for selecting the optimal values of zeolite circulation rate and feedstock linear velocity.

Biomass-derived furanics play a pivotal role in chemical industries, with 2-methyltetrahydrofuran (2-MTHF), a hydrogenated product of levulinic acid (LA), being particularly significant. 2-MTHF finds valuable applications in the fuel, polymer, and chemical sectors, serving as a key component in P-series biofuel and acknowledged as a renewable solvent for various chemical processes. Numerous research groups have explored catalytic systems to efficiently and selectively convert LA to 2-MTHF, using diverse metal-supported catalysts in different solvents under batch or continuous process conditions. This comprehensive review delves into the impact of metal-supported catalysts, encompassing co-metals and co-catalysts, on the synthesis of 2-MTHF from LA. The article also elucidates the influence of different reaction parameters, such as temperature, type and quantity of hydrogen source, and time. Furthermore, the review provides insights into reaction mechanisms for all documented catalytic systems.

CuII-Hfur–imidazole] compounds as precursors of efficient hydrogenation and reductive alkylation catalysts in flow systems

Influence of annealing texture on dynamic tensile deformation characteristics of Dual phase steel

Context: Continuous processing is becoming popular in the pharmaceutical industry for its cost and quality advantages.Objective: This study evaluated the mechanical properties, uniformity of dosage units and drug release from the tablets prepared by continuous direct compression process.Materials and methods: The tablet formulations consisted of acetaminophen (3–30% (w/w)) pre-blended with 0.25% (w/w) colloidal silicon dioxide, microcrystalline cellulose (69–96% (w/w)) and magnesium stearate (1% (w/w)). The continuous tableting line consisted of three loss-in-weight feeders and a convective continuous mixer and a rotary tablet press. The process continued for 8 min and steady state was reached within 5 min. The effects of acetaminophen content, impeller rotation rate (39–254 rpm) and total feed rate (15 and 20 kg/h) on tablet properties were examined.Results and discussion: All the tablets complied with the friability requirements of European Pharmacopoeia and rapidly released acetaminophen. However, the relative standard deviation of acetaminophen content (10% (w/w)) increased with an increase in impeller rotation rate at a constant total feed rate (20 kg/h). A compression force of 12 kN tended to result in greater tablet hardness and subsequently a slower initial acetaminophen release from tablets when compared with those made with the compression force of about 8 kN.Conclusions: In conclusion, tablets could be successfully prepared by a continuous direct compression process and process conditions affected to some extent tablet properties.