| 主权项 |
1. A process for improving the properties of a distillate feedstock having an organic nitrogen concentration, a polyaromatics concentration and a cetane index, wherein said process comprises:
contacting said distillate feedstock with a first catalyst contained within a first reaction zone for the hydrodenitrogenation of organic nitrogen compounds and for the saturation of polyaromatic compounds, wherein said first reaction zone is operated under suitable hydrodenitrogenation and polyaromatics saturation conditions, including a first reaction zone reaction pressure in the range of from above 4.8 MPa (700 psig) to about 13.8 MPa (2000 psig) and a first reaction zone reaction temperature in the range of from 260° C. (500° F.) to 430° C. (806° F.), wherein said first reaction zone is defined by a first reactor vessel, wherein within said first reaction zone is included at least two distinct catalyst beds, wherein each of said at least two distinct catalyst beds each comprising a bed of catalyst particles supported upon a support internal that spans the cross-sectional area of said first reactor vessel and provides for the support of each of said bed of catalyst particles and each of said bed of catalyst particles has a bed depth, and wherein said catalyst particles include said first catalyst, which is of the type that comprises a Group VIII metal or a Group VI metal, or a combination of both, on an inorganic oxide support, wherein each of said at least two distinct catalyst beds is placed within said first reaction zone in a spaced relationship to each other so as to thereby provide a void volume between each of said at least two distinct catalyst beds within said first reaction zone wherein a quench fluid may be introduced for interbed quenching and temperature control; and yielding from said first reaction zone a treated effluent having a reduced organic nitrogen concentration relative to said organic nitrogen concentration and a reduced polyaromatics concentration relative to said polyaromatics concentration; separating said treated effluent into a heavy fraction and a lighter fraction; and contacting said heavy fraction with a second catalyst contained within a second reaction zone for the saturation of monoaromatics, wherein said second reaction zone is operated under suitable monoaromatics saturation conditions, including a second reaction zone reaction pressure in the range of from above 4.1MPa (600 psig) to about 13.1MPa (1900 psig), which is in the range of from 10 to 100 psig greater than said first reaction zone reaction pressure, and a second reaction zone reaction temperature in the range of from 204° C. (400° F.) to 430° C. (806° F.); yielding from said second reaction zone a reactor product, wherein said second catalyst comprises a base metal catalyst comprising either a nickel component or cobalt component and either a molybdenum component or a tungsten component supported on an inorganic oxide support, and wherein said reactor product comprises a distillate portion having an enhanced Cetane Index relative to said cetane index of said distillate feedstock; combining make-up hydrogen into said heavy fraction to provide a resulting mixture, comprising said make-up hydrogen and said heavy fraction, and introducing said resulting mixture into said second reaction zone; passing said reactor product to a second separator for separating said reactor product into a first hydrogen portion and a dearomatized distillate portion; and passing said dearomatized distillate portion to a product stripper for removing lighter hydrocarbons from said dearomatized distillate portion and providing a diesel product having a high Cetane Index. |
