Development of a three way catalytic converter for elimination of hydrocarbons, carbon monoxide and nitric oxide in automotive exhaust

Kandilli, Nur
In this work, slurries of powder catalysts are washcoated on 22 mm diameter and 13 mm height cordierite monoliths. CeO2-ZrO2 (CZO) and CeO2-ZrO2- Al2O3 (CZAO) mixed oxides are synthesized by co-precipitation and sol-gel methods respectively, to be used as support materials of Pd and Rh metals. Metal loaded CZO is mixed with gamma phase alumina. Powder catalysts and their slurries are characterized by XRD, BET, ICP-MS and the monolithic catalysts are imaged by SEM. Catalytic activities of monolithic catalysts are tested in dynamic test system which is computerized and basically composed of gas flow control and conditioning units, split furnace, quartz reactor, mass spectrometer and CO analyzer. Gas mixture containing CO, C3H6, C3H8, NO, H2, O2, CO2, SO2, H2O and N2 is used to simulate the exhaust gas of gasoline vehicles. O2 is oscillated at 1 Hz frequency around the stoichiometric condition. Monolithic catalyst in the reactor is heated and cooled between 150 ºC and 600 ºC. Gas composition data from massspectrometer and CO analyzer and temperature data from thermocouple at the monolith entrance, are converted to conversion versus temperature graphs. Results of 26 activity tests are compared. Catalyst containing coimpregnated CZO support material with metals, showed the lowest loss of catalytic performance after exposure to SO2 during activity tests. Catalyst containing separately impregnated CZO support material, showed the highest resistance against thermal aging at 900 ºC and 1000 ºC, and even improved catalytic activity after aging. These catalysts showed higher resistances against the applied procedures than the commercial catalyst.


Modeling and rheology of HTPB based composite solid propellants
Erisken, C; Gocmez, A; Yilmazer, U; Pekel, F; Özkar, Saim (Wiley, 1998-08-01)
The propellant with the minimum viscosity required for a defect-free casting can be obtained by proper selection of the size and fractions of solid components leading to maximum packing density. Furnas' model was used to predict the particulate composition for the maximum packing density. Components with certain size dispersions were combined to yield a size distribution that is closest to the optimum one given by Furnas for maximum packing. The closeness of the calculated size distribution to the optimum o...
Dry grinding kinetics of binary mixtures of ceramic raw materials by Bond milling
Ipek, H; Ucbas, Y; Yekeler, M; Hoşten, Çetin (Elsevier BV, 2005-01-01)
The kinetics of batch dry grinding of binary mixtures of ceramic raw materials, namely quartz-kaolin, quartz-potassium feldspar and kaolin-potassium feldspar, from the feed sizes of -3.350 + 2.360, -2.000 + 1.400, -0.850 + 0.600, -0.500 + 0.355 and -0.300 + 0.212 mm have been determined using a Bond mill with a mixture of ball sizes of 38.10, 31.75, 25.40, 19.05 and 12.70 mm diameter and total mass of 22.648 kg. The Bond mill used was a size of 30.5 cm diameter, 30.5 cm length, with a total volume of 22,272...
Performance assessment of cement grout borehole plugs in basalt
Akgün, Haluk (Elsevier BV, 1994-01-01)
Flow tests have been conducted on expansive cement grout plugs with diameters of 160 mm and 200 mm, and length-to-diameter ratios of one, in boreholes in basalt blocks and in steel pipes. Two types of flow tests have been performed: pseudo-constant head tests and transient pulse tests. Hydration temperatures of cement grout plugs have been monitored in steel pipes with inside diameters ranging from 110 mm to 200 mm. During flow tests, basalt blocks have fractured, presumably due to water injection pressure,...
Performance of solar cells fabricated on black multicrystalline Si by nanowire decoration
Es, Fırat; Çiftpınar, Emine Hande; Demircioğlu, Olgu; Günöven, Mete; Kulakci, Mustafa; Turan, Raşit (2015-03-30)
Vertically aligned Si nanowire (NW) arrays fabricated by metal-assisted etching technique were applied to industrial sized (156 mm x 156 mm) multicrystalline Si cells as an anti-reflective (AR) medium. The NW lengths (between 0.15 and 2.2 mu m) were controlled by etch duration from 5 to 50 min. A completely black surface could be observed, demonstrating excellent AR properties in the entire range of the solar spectrum, even without additional anti-reflective coating layer (e.g., SiNx:H). Standard Si solar c...
Preparation and Characterization of Polypropylene/Serpentine Composites
Tan, Semra; Tincer, İsmail Teoman (Wiley, 2011-07-15)
Composites of serpentine and polypropylene (PP) were prepared by twin-screw extrusion. Serpentine was collected as rocks from the Ankara-Beynam region and ground into powder with an average particle size of about 3 mu m for composite production. Both as-received (rock) and powdered serpentine were characterized. A silane coupling agent (SCA), gamma-aminopropyl triethoxy silane, was used for the surface treatment of serpentine. Mechanical properties of the composites were measured in terms of impact strength...
Citation Formats
N. Kandilli, “Development of a three way catalytic converter for elimination of hydrocarbons, carbon monoxide and nitric oxide in automotive exhaust,” M.S. - Master of Science, Middle East Technical University, 2010.