Nektor-ULCC case study at Total Antwerp
Successful application of the Nektor-ULCC FCC catalyst in the Total Antwerp FCC 1 unit
Anne-Lies van den Eynde and Tom Knaepkens, Total Antwerp Refinery
Michel Melin, Grace Davison Refining Technologies Europe
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This article describes how the Total Antwerp FCC unit (FCC 1) has improved the unit’s yield structure by using Nektor-ULCC, which is an FCC catalyst based on the Grace Davison EnhanceR technology platform. A brief description of the catalyst technology is followed by a discussion of the commercial trial of Nektor-ULCC at the Total Antwerp refinery. FCC unit operating data and ACE pilot plant data are provided to highlight the positive changes in yield structure and the resulting economical benefits provided by Nektor-ULCC.
A significant breakthrough in FCC catalyst design was achieved with the introduction of the Grace Davison EnhanceR technology platform. This platform involves the four technologies pore restructuring (EPR), Metals resistance (EMR), acidity modification (EAM) and structure stabilisation (ESS). Rather than making separate modifications to the zeolite and matrix components, the EnhanceR plant enables processing of input materials, intermediate products and end-product FCC catalysts.
Whereas the first generation of EnhanceR catalysts each utilised two technologies, further development provided a second generation of catalyst families that incorporated an additional EnhanceR technology. For example, Nektor-ULCC is formulated with the EPR and EMR technologies used in Nektor but also utilises the EAMR technology to provide even better bottoms cracking through a further reduction in delta coke. Users of Nektor-ULCC are seeing further improvement in coke selectivity, and are using this to increase conversion at maximum feed rate, achieving even better bottoms upgrading without requiring additional air.
Total Antwerp refinery
With a refinery capacity of 18 million MT per year of crude, Total Antwerp is the second largest refinery in Europe. Two FCC units produce a total throughput of 700 m_/h (106 000 bpd) and process up to 70% of hydrotreated atmospheric residue. The FCC 1 unit was built in 1956, and is a UOP stacked design, and it is the smaller of the two units with a capacity of 175 m_/h. It was revamped in 2001 by Total/Stone & Webster to include Stone & Webster elevated radial feed nozzles, a packed stripper and an external riser terminated by a simple catalyst separation device. The air blower capacity is supplemented by oxygen addition, and an ESP was installed a little later behind the CO boiler.
The FCC units are operated in partial burn without a catalyst cooler. The feedstock processed contains a high content of contaminant metals, as demonstrated by the nickel and vanadium levels on the e-cat, which typically reach levels of 10 000 ppm. Consequently, the refinery required an extremely coke-selective FCC catalyst, making it an ideal candidate for assessing the performance of the Nektor-ULCC catalyst.
The trial of the Grace Davison Nektor-ULCC catalyst began in February 2008 in the FCC 1 unit. It replaced the Nektor-676T catalyst, which was introduced successfully on the market at the end of 2003 on the same unit.1 During the catalyst trial, the operating objective was to use the improved coke selectivity of Nektor-ULCC to increase either the feed concarbon content or the conversion (by operating at higher e-cat MAT) depending on the relative economic benefits. The performance of the Nektor-ULCC catalyst was assessed using FCC unit check run data, as well as ACE pilot plant testing on equilibrium catalyst.
FCC unit check run data
To allow an accurate and fair evaluation of the performance of Nektor-ULCC in comparison to Nektor-676, good-quality and representative check runs were selected from operating periods in which the operating conditions were similar in terms of feed quality and unit severity. Tables 1 to 4 show the FCC unit operating conditions, feed quality, e-cat properties and FCC unit yields, respectively.
During the trial period, the unit was operated with an e-cat activity that was 2 wt% higher (see Table 3). This was possible due to the better intrinsic delta coke of the Nektor-ULCC catalyst. As a result, a gain in conversion of 1.4 wt.% (221°C TBP) was observed when using the Nektor-ULCC catalyst (see Table 4). This translated into a 1.1 wt.% increase in the total cut naphtha yields, and a 0.4 wt% increase in LPG yield.
ACE pilot plant test data
ACE pilot plant tests were carried out using e-cat samples collected from the Antwerp FCC unit during the periods of Nektor-676T and Nektor-ULCC catalyst usage. The characterisation data for these samples are summarised in Table 5, and it can be seen that at similar metals levels Nektor-ULCC provides lower gas and coke factors, as well as a lower hydrogen yield.
The ACE study yields at constant coke yield are shown in Table 6, and it can be seen that compared with Nektor the Nektor-ULCC catalyst provides an increase of 1.5 wt% conversion. This provided a slight increase in LPG yield of 0.6 wt%, and an increase of gasoline yield by 0.8 wt%. This is consistent with the FCC unit yields shown in Table 4.
Assuming a margin of $1 per MT of feed per wt% conversion gain, the additional profit achieved with the move to Nektor-ULCC in the Total Antwerp FCC 1 unit amounted to $2 million per year. The commercial trial was considered a complete success, and the refinery decided to continue using Nektor-ULCC. Currently, there are 11 FCC units in the EMEA region using Nektor-ULCC.
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