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Topsoe’s two-stage HDS/HDA technology

Intelligent integration

Refiners have to contend with increasingly stringent specifications for diesel fuel, while increasing production of diesel products from difficult feedstocks.
TOPSOE™’s hydrotreating solutions help refiners process even hard-to-process or alternative feeds, while meeting stringent emissions and clean fuel product requirements. We can also optimize your operating conditions and catalyst loadings to cut investment costs and utility consumption.

TOPSOE™’s dearomatization technology and catalysts (HDA) are especially well-suited for treating heavy feedstocks to produce distillates with lower sulfur and aromatics levels, reduced density, or a higher cetane number. Our two-step process has a HDS stage for sulfur and nitrogen removal, followed by a HDA stage for removing polyaromatics and reducing the aromatic content.

Reduce aromatics content – increase cetane number
TOPSOE™ was among the first to introduce the two-stage HDS/HDA technology and catalysts for deep dearomatization of gas oil feedstocks and manufacturing ultra-clean diesel fuels. Our process is currently operating in several industrial units worldwide and has a proven track record for reliability and stability.

The first stage of this process is similar to TOPSOE™'s conventional hydrotreating scheme. In this stage, deep HDS and HDN take place using a base metal catalyst. The effluent from the first reactor is sent to a stripper, which removes H2S and NH3 from the liquid hydrocarbon, exiting at the bottom of the stripper. It is very important that the hydrocarbon liquid is free of H2S, as it acts as a poison for the noble metal catalyst in the 2nd stage.

The overhead vapor from the stripper containing H2S, NH3, and light ends passes through an amine wash to remove impurities from the hydrogen-rich gas. The hydrogen stream is used as treat gas in the HDA stage, where noble metal catalysts saturate aromatics in the distillate from the stripping column. This stage dramatically reduces the aromatics content of the diesel product and raises the cetane number. Commercial operation has proven designs with less the 3 wt% aromatics and cetane number increase of more than 11.

Lowering the cost of maximizing yields
The novel two-stage process from TOPSOE™ is field-proven to cut investment costs and ongoing energy consumption. For more information, please contact TOPSOE™.

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Morten Krogh Johansen
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