Hydroprocessing configuration for low sulfur diesel
AssigneeExxonMobil Research and Engineering Company
InventorsRichard A. Demmin, Michael A. Hayes, Kenneth M. Lee
Life of this patent
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Abstract
Methods are provided for producing low sulfur diesel fuels by performing multi-stage hydroprocessing at low pressure on a distillate feed. A feedstock suitable for forming a diesel fuel product is hydrotreated at a hydrogen partial pressure of 500 psig or less in at least two reaction stages. In order to provide improved desulfurization and/or aromatic saturation activity in the final stage, the stages are configured so that the highest hydrogen pressure and/or highest hydrogen purity are delivered to the last hydrotreatment stage.
Claims11
A method for producing low sulfur distillate products, comprising:
- exposing a feedstock having a sulfur content of at least about 1500 wppm and a first content of polyaromatic hydrocarbons to hydrotreating catalyst in the presence of a recycled hydrogen treat gas stream in at least a first reaction stage under first effective hydrotreating conditions to produce an intermediate effluent comprising at least a gas phase fraction and a liquid fraction;
- separating the liquid fraction from the gas phase fraction, the separated liquid fraction having a sulfur content of at least about 250 wppm;
- scrubbing the gas phase fraction to remove at least a portion of H2S, NH3, or a combination thereof from the gas phase fraction;
- compressing the scrubbed gas phase fraction;
- exposing the separated liquid effluent to a second hydrotreating catalyst in the presence of the compressed gas phase fraction and a fresh hydrogen treat gas stream under second effective hydrotreating conditions to produce hydrotreated effluent;
- and
- separating the hydrotreated effluent to form at least a diesel boiling range product and a second gas phase fraction, the diesel boiling range product having a sulfur content of 25 wppm or less and a polyaromatic hydrocarbon content of about 7 wt % or less,
- wherein the recycled hydrogen treat gas stream comprises at least a portion of the second gas phase fraction.
Dependencies are inferred from the claim text.