Methods for producing diesel range materials having improved cold flow properties

Abstract

Embodiments of a method for producing a diesel range material having improved cold flow properties are provided. In one embodiment, the method includes the steps of providing a waxy diesel range feedstock, producing an intermediary product stream containing a predetermined amount of oxygenated organocompounds from the waxy diesel range feedstock, and contacting the intermediary product stream with a dewaxing catalyst under process conditions at which the oxygenated organocompounds chemically interact with the dewaxing catalyst to convert a portion of the n-paraffins within the intermediary product stream to iso-paraffins while minimizing cracking of the diesel range material.

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to fuel production and, more particularly, to embodiments of a method for producing diesel range materials having improved cold flow properties.DESCRIPTION OF RELATED ART[0002]Diesel range materials produced from vegetable oil hydrotreating or Fischer Tropsch (“F-T”) synthesis provide excellent cetane ratings. However, such materials also typically contain undesirably high quantities of long chain (C18-C24) n-paraffins and, consequently, suffer from poor cold flow properties; e.g., undesirably high cloud points (i.e., temperatures at which some long straight chain paraffins begin to precipitate from the fluid and create a cloudy appearance) and undesirably high pour points (i.e., minimum temperatures at which the fluid will readily flow or can be pumped under prescribed operating conditions). In order to improve cold flow properties, diesel range materials produced from vegetable oil hydrotreating and F-T liquids ar...

AI Technical Summary

Benefits of technology

[0005]Embodiments of a method for producing a diesel range material having improved cold flow properties are provided. In one embodiment, the method includes the steps of providing a waxy diesel range feedstock, producing an intermediary product stream containing a predetermined amount of oxygenated organocompounds from the waxy diesel range feedstock, and contacting the intermediary product stream with a dewaxing catalyst under process conditions at which the oxygenated organocompounds chemically interact with the dewaxing catalyst to increase catalyst selectivity and provide a diesel range material having an improved iso-normal paraffin ratio.

[0006]In a further embodiment, the method includes the steps of deriving a diesel range feedstock containing n-paraffins and oxygenated organocompounds from a biorenewable source, removing a portion of the oxygenated organocompounds to yield an intermediary product stream containing a predetermined amount of retained oxygenated organocompounds, and hydroisomerizing the intermediary product stream with a dewaxing catalyst under process conditions at which the oxygenated organocompounds chemically interact with the dewaxing catalyst to increase catalyst selectivity and provide a diesel range material having an improved iso-normal paraffin ratio.

[0007]In a still further embodiment, the method includes the steps of converting carbon monoxide and hydrogen into the waxy diesel range feedstock utilizing Fischer-Tropsch synthesis, removing a portion of the oxygenated organocompounds to yield a intermediary product stream containing a predetermined amount of retained oxygenated organocompounds, and hydroisomerizing the intermediary product stream with a dewaxing catalyst under process conditions at which the oxygenated organocompounds chemically interact with the dewaxing catalyst to increase catalyst selectivity and provide a diesel range material having an improved iso-normal paraffin ratio.

Problems solved by technology

As is well-known in the petroleum-refining industry, the hydroisomerization process is accompanied by cracking of the diesel range materials into less desirable lighter products, such as naphtha range products.

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