Bimetallic Pd-Pt catalyst was successfully prepared via conventional heating (CH), microwave (MW), and ultrasonic irradiation (US) methods. Bimetallic Pd-Pt nanoparticles stabilized with polyvinylpyrrolidone (PVP) were prepared with molar ratio of PVP to metal, 40:1. Smaller particles sizes with narrow distribution obtained after 30min and 10min with US and MW methods respectively. All the particles are spherical or near spherical in shape.

The average particles size and size distribution for Pd-Pt (US) nanoparticles was 1.28 ± 0.29 nm, while for Pd-Pt (MW) nanoparticles was 1.05 ± 0.21 nm. The average particles sizes of these bimetallic nanoparticles are comparable with the classical CH method, which was 1.23 ± 0.25 nm. Based from the XPS analysis, surface compositions of Pd and Pt show that PdPt(CH) and PdPt(MW) catalyst were enriched with Pd, meanwhile PdPt (US) composition was comparable and it might be in alloy structure formation. The activity of these three catalysts for the hydrogenation reaction of palm olein was studied. The reaction conducted under ambient temperature and atmospheric pressure. A molar ratio of palm olein to catalyst of 25000:1 has been used in the hydrogenation reaction to determine the conversion of linoleate, selectivity of trans-isomer and iodine value (IV) in the hydrogenated palm olein. After 180 min of reaction, full conversion achieved with Pd-Pt (MW) catalyst, while only 91.4% and 80.6% conversion achieved with Pd-Pt (US) and Pd-Pt (CH) respectively. However, the Pd-Pt (MW) catalyst shows the highest elaidate selectivity after 180 min, which was up to 13.1%, meanwhile the elaidate selectivity of 11.82% and 8.1% for both Pd-Pt (US) and Pd-Pt (CH) respectively. Even though higher conversion of linoleate achieved in short time and lower trans selectivity produced with Pd-Pt bimetallic catalyst. The IV calculated shows that Pd-Pt (MW) catalyst has the lowest IV then followed by Pd-Pt (US) and Pd-Pt (CH) catalysts.

written by Journal of Chemical Engineering and Process Technology

A majority of vacuum processes use the Thermal Mass Flow Meter (TMFM) as metering device for process gas. The purpose of this paper is to establish cross compatibility relationship of the TMFM with different process gases. This paper uses a compressible Computational Fluid Dynamic (CFD) solver to understand the behavior of TMFM with different process gases. The change in the characteristic curve at lower pressures has also been studied. Empirical correlations have been developed so that the change in characteristic curve of TMFM can be predicted accurately for different gases based on their physical properties.

written by Journal of Chemical Engineering and Process Technology

Gas-solid mixing jet flows are an essential feature of typical chemical engineering processes. A proper analysis of the mixture flow optimizes process qualities and efficiencies. In this contribution, a numerical study of the solids dispersion in a two-phase jet flow is presented. The mathematical model treats the gas and the solid phases with an Eulerian approach. Radial profiles of the solid-phase mean velocity were computed on five axial levels, subdivided in five cases, in the mixing jet flow using a two-phase 3D computational fluid dynamics model. The computed solids velocities were compared with experimental data on a jet with an internal diameter of 12mm, at different inlet conditions of solid mass load for rates (3 to 7) and velocities (8 to 16m/s). The mean particle diameter used was 50μm and a density of 2500kg/m³.Three different drag models were applied to evaluate the solids dispersion, Wen and Yu [1], Gidaspow [2] and Massarani [3] correlations, the latter being a continuous one. The two-equation (k-ε) turbulence model was employed to describe the gas-phase, while the zero-equation (kinematic viscosities analogy) turbulence model describing the solid-phase in a jet flow. The mathematical model predicts a developed flow regions similar to that found experimentally.

written by Journal of Chemical Engineering and Process Technology