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Commercialization of mesoporous USY zeolite

Zant, L.M. (2015) Commercialization of mesoporous USY zeolite. Bachelor's Thesis, Industrial Engineering and Management.

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Abstract

Zeolites are catalysts which are mainly used for FCC (fluid catalytic cracking) in an oil refinery. Conventional Ultra Stable Y (USY) zeolite is used in almost all the FCC systems due to its good stability, octane-producing cracking results and better selectivity on coke. This zeolite has a high silica/aluminum rate with high surface areas, being a consequence of ordered micropores of molecular dimensions that enable shape-selective catalytic transformations. The drawback in most industrial reactions catalysed by zeolites is the low catalyst utilisation. This is caused by the restricted access and slow transport of the product through the zeolite. Therefore the FCC unit is not able to operate at its full potential. Various methods have been claimed to introduce mesoporosity in zeolites in order to enhance the mass transfer, however no single feasibility study has been reported to date. The problem holder prof. Javier Garcia-Martinez also introduced a method, after patenting his research on mesoporous zeolite Y the cost of the surfactant templates for large-scale applications have been a concern. A mesoporous zeolite Y yield, compared to conventional USY zeolite, more valuable products and reduces the yield of residue (coke), so there is a clear economic benefit. However, the mesoporous zeolite Y is more expensive than a conventional USY zeolite; because the first can be produced cheaply, while the second requires the use of large quantities of an organic surfactant that is sacrificed after the synthesis. The goal of this project is to find out if commercialization of mesoporous zeolite Y is technically and economically feasible. As a reference, the refinery of Pernis Shell will be used. For the production of m-USY zeolite, claimed by Rive Technology (denoted as “Molecular HighwayTM”), conventional zeolite Y is treated with CTAB (cetyltrimethyl ammonium bromide) mixed with a base to avoid desilication. These will form surfactant templates that create the mesopores in the crystal structure. The templates are burned out and cannot be reused; which is one of the main reasons for the higher production cost of the mesoporous USY zeolite. The produced m-USY zeolite can be directly replaced by the USY zeolite as catalyst. The claimed advantages are higher conversion, less over-cracking, reduced coke yield and good activity and hydrothermal stability compared to the conventional USY zeolite. In the FCC unit of a refinery the long chain carbons are cracked with use of zeolite, during the cracking process zeolite deactivates due to the yield of coke in the crystals. To activate the zeolite the coke is burned from the zeolite crystals in the regenerator. An FCC unit uses around 2-4 ton of zeolite per day, to maintain a certain activity level. It was identified that the implementation of a new catalyst in a FCC unit will bring some risks, because that the FCC unit is constrained by three parts; the fractionator, the hot air compressor and the emission of flue gas. Commercialization of the “Molecular HighwayTM” showed good cracking results in a test trial at the refinery in Alon USA. With these results it is estimated that an economic uplift could be achieved of $2.50/BBL. This uplift was achieved with a 78% catalyst change-out. Making use of the cost calculation on the manufacturing of m-USY zeolite, and the economic uplift that was achieved during the test trial, incremental economics were used to calculate the profit of the implementation. The profit with use of 78% catalyst change-out and based on the Shell refinery will be ~10% of the investment costs. Some discussion points are made on the FCC feed that was used at the test trail; the economic uplift not being transparent enough and will depend on many factors, the high costs of CTAB and uncertainty around the production quantity of CTAB and the large excess of naphtha in US refineries that will likely be exported to Europe. It can be concluded from this feasibility study that based on the given information it is technically feasible to commercialize the m-USY zeolite. On the other hand the economic commercialization of m-USY zeolite, based on the refinery of Shell, will not be feasible. The calculated profit is not enough to overcome the risks of implementation.

Item Type: Thesis (Bachelor's Thesis)
Degree programme: Industrial Engineering and Management
Thesis type: Bachelor's Thesis
Language: English
Date Deposited: 15 Feb 2018 08:05
Last Modified: 15 Feb 2018 08:05
URI: http://fse.studenttheses.ub.rug.nl/id/eprint/12908

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