Hydroprocessing Economics

M0S2 is one of the most active hydroprocessing catalysts, but it is expensive, and the economical way to apply it is as highly dispersed material on a support, y-Al202. The activity of the supported catalyst is increased by the presence of promoter ions, Co " or Ni ". The stmctures of the catalysts are fairly well understood the M0S2 is present in layers only a few atoms thick on the support surface, and the promoter ions are present at the edges of the M0S2 layers, where the catalytic sites are located (100,101). 

With these criteria in mind, various reactors have been designed to satisfy the needs of the hydroprocesses, including hydrodesulfurization (McEvoy, 1996). Thus, reactors may vary from as little as 4 ft. in diameter to as much as 20 ft. in diameter and have a wall thickness anywhere from 4.5 to 10 in. or so. These vessels may weigh from 150 tons to as much as 1000 tons. Obviously, before selecting a suitable reactor, shipping and handling requirements (in addition to the more conventional process economics) must be given serious consideration. 

Previous reference has been made to the benefits of removing an asphaltene fraction from the feedstock prior to hydroprocessing and prior to the application of a hydroconversion process. Chemically, this approach may be sound but an economic benefit must also be realized. This will be determined on a case by case basis. 

There is a major economic incentive to extend the current HC processes to enable heavier feedstocks to be converted to lighter, higher-value transportation fuels. Studies by Idemitsu indicate that iron-modified zeolite catalysts significantly enhance conversion when heavy oils such as long residue are hydroprocessed (65). Nevertheless, major technical barriers exist which make high conversions and product selectivities difficult to achieve with truly heavy feeds (end boiling points beyond 620 °C) - these include ... 

In Kuwait s refineries, over 250 000 barrels of heavy residues higher in sulfur, and metals are upgraded and converted to high quality products by catalytic hydroprocessing, bringing substantial economic returns to the country. These operations generate a substantial amount of deactivated spent catalysts as solid waste every year. Currently, about 6000 tons of spent catalysts are discarded as solid wastes from Kuwait s refineries annually. This will increase further and exceed 10 000 tons/y when a fourth refinery is built to process heavy crudes and residues. 

Handling and utilization has been the subjected of some investigations in the Kuwait (KISR) and Egypt (EPRI) laboratories. In most of the previous studies in both laboratories, rejuvenation of spent hydroprocessing catalysts for reuse was addressed. Up to 70-80% of the spent catalyst was reclaimed, in the applied processes of both laboratories, with HDS activity as high as 94-95 % of fresh catalyst. Therefore, from the economic point of view, the rejuvenation and reuse of the catalyst is feasible with an internal rate of return. 

Ou, L., et al., 2015. Techno-economic analysis of transportation fuels from defatted microalgae via hydrothermal liquefaction and hydroprocessing. Biomass and Bioenergy 72 (0), 45-54. 

Determining metals content in hydroprocessing catalysts after a certain period of operation is very important to estimate metal deposition rate and catalyst life, and hence identify, for instance, which catalyst is better to process certain feed than others. These parameters are of great interest not only to catalyst manufacturers but also to refiners, process designers, and catalysis researchers, since the whole economics of a hydrotreating plant is mostly determined by catalyst life. 

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