Current Issue : October - December Volume : 2020 Issue Number : 4 Articles : 5 Articles
The ability to track & trace materials is a key feature in the entire chain, and it\nensures circularity principles. Examples from plastic recycling show the\nenormous added value that analytical technology can have for the circular\neconomy. During polymer production and recycling processes, pigments can\nbe added for different purposes; e.g. as colouring agent of the polymeric\nproduct but also as tracer for tracking process development and control in the\nfinal recycle products versus possible by-products. An analytical method for\ntracking the pigment Solvent Blue 15 in input materials, in intermediates as\nwell as in recyclates was developed by tracing and quantifying an indicator\nmetal which is copper (Cu). Therefore, suitable digestion procedures and a\nquantification method by high resolution inductively coupled plasma mass\nspectrometry...................
In this work, the possibility of enhanced activity during the hydrodesulfurization\nof dibenzothiophene over certain nano-MoS2 catalyst due to the presence\nof H2S was examined by focusing on the reaction kinetics. With H2S generated\nin situ , the overall reaction followed the autocatalytic rate law; while in the\nabsence of H2S the kinetics indicated a pseudo-first-order reaction. H2S appears\nto modify the relative contributions of parallel hydrogenation and desulfurization\nreactions by drastically increasing the hydrogenation rate. Kinetic\nmodels were developed that describe the hydrodesulfurization reaction\nat various H2S concentrations, and the kinetic parameters and adsorption\nequilibrium constants associated with this process were estimated by fitting\nthe experimental data. The results suggest that the promotion and/or inhibition\nof hydrodesulfurization by H2S likely result from the same overall reaction\nmechanism....
An HYSYS model for the crude distillation unit of the Port Harcourt Refining\nCompany has been developed. The HYSYS model developed includes 3 mixers,\n3 heaters, 1 heat exchanger, 1 desalter (3-phase separator), 2-phase separator\nand the main fractionating column. The raw crude was characterized\nusing Aspen HYSYS version 8.8 and the developed model was simulated with\nthe industrial plant data from the Port Harcourt Refining Company. The\nHYSYS model gave component mole fractions of 0.2677, 0.1572, 0.2687,\n0.0547, 0.2517 for Naphtha, Kerosene, Light Diesel Oil (LDO), Heavy Diesel\nOil (HDO) and Atmospheric Residue and when compared to plant mole fractions\nof 0.2710, 0.1560, 0.2650, 0.0530, 0.2550 gave a maximum deviation of\n3.2%. The HYSYS model was also able to predict the temperature and the tray\nof withdrawal for Naphtha, Kerosene, Light Diesel Oil (LDO), Heavy Diesel\nOil (HDO) and Atmospheric Residue as follows: tray 1.........................
A dichlorosilane gas and a trichlorosilane gas in ambient hydrogen were evaluated\nto show their different gas flow motions in a slim vertical cold wall\nchemical vapor deposition reactor for the Minimal Fab system. This evaluation\nwas performed for improving and controlling the film qualities and the\nproductivities, using two quartz crystal microbalances (QCM) installed at the\ninlet and exhaust of the chamber by taking into account that the QCM frequency\ncorresponds to the real time changes in the gas properties. Typically,\nthe time period approaching from the inlet to the exhaust was shorter for the\ntrichlorosilane gas than that for the dichlorosilane gas. The trichlorosilane gas\nwas shown to move like plug flow, while the dichlorosilane gas seemed to be\nwell mixed in the entire chamber....
The processing of iron ore to recover the valuable iron oxide minerals is\ncommonly carried out using spiral concentrators that separate valuable\nminerals from non-valuable ones on the basis of the specific gravity of\nminerals. This paper shows that the analysis of the operation of spirals\nshould not only focus on the minerals (as it is usually the case), but should\nalso consider the particle size of these minerals. Indeed, the sampling of\ntwo industrial iron ore circuits and the data processing of the resulting\nmeasurements show that unexpectedly about 10% of the coarse heavy iron\noxide minerals are not recovered by the spirals of the two circuits. Tests\nconducted by an independent research center confirm this plant observation.\nThe pilot plant tests also show that the wash water flowrate addition\nmay adversely affect the recovery of coarse heavy mineral particles. A mathematical\nmodel for the spiral was implemented into a simulator for an\niron ore gravity concentration circuit. The simulator shows a potential\n0.7% increase of iron recovery by simply changing the strategy used to distribute\nthe wash water between the rougher and the cleaner/recleaner spirals\nof the circuit. The simulator also shows that the introduction of a hydraulic\nclassifier into the gravity concentration circuit yields a marginal\nimprovement to the performances of the circuit....
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