Catalysis Today, Vol.109, No.1-4, 69-75, 2005
Long-term evaluation of NiMo/alumina-carbon black composite catalysts in hydroconversion of Mexican 538 degrees C+ vacuum residue
Alumina with (8-18 wt.%) carbon black composite (AMAC) supports was prepared as bimodal extrudates, containing 11-20% of total pore volume as macropores (i.e. > 1000 angstrom). These supports, in spite of containing carbon black and macropores, showed good side crushing strength (0.67-1.19 kg/mm) after pyrolysis in 6% O-2/N-2. AMAC-catalysts were obtained after impregnating these alumina-carbon black supports with Ni and Mo, to obtain 3.5 wt.% NiO and 15 Wt-% MoO3. These catalysts were evaluated for about 700 h in the hydroconversion of a Mexican vacuum residue (538 degrees C+) at 415 degrees C, 200 kg/cm(2), H-2/HC = 6000 ft(3)/barrel in a pilot plant equipped with a Robinson-Mahoney reactor. In comparison with a commercial bimodal alumina-based catalyst (ComCat), AMAC catalysts showed much fewer sediments and less Conradson carbon formation. Initial HDS in AMAC containing macropores can be as high as 92%, while that in a ComCat is 86%. On average, yields of naphtha and kerosene were 2.6 and 1.34 times higher with AMAC catalysts than those with ComCat, while diesel yields were similar. (c) 2005 Elsevier B.V. All rights reserved.
Keywords:hydroconversion;hydrodesulfurization;hydrodenitrogenation;vacuum residue;H-oil;carbon-black;alumina support;macropores