Upgrading shale oil by a combination process

A process for reducing the nitrogen content of a shale oil containing lighter shale oil compounds including lighter nitrogen-containing compounds and heavier shale oil compounds including heavier nitrogen-containing compounds comprising:

• separating the shale oil into lighter shale oil compounds and heavier shale oil compounds;
• selectively removing at least a portion of the lighter shale oil compounds containing nitrogen from the separated lighter shale oil compounds to form a first nitrogen-lean raffinate;
• and
• selectively removing at least a portion of the heavier shale oil compounds containing nitrogen from the separated heavier shale oil compounds to form a second nitrogen-lean raffinate.

A process for reducing the nitrogen content of shale oil containing nitrogen-containing compounds comprising:

• distilling shale oil to form a distillate, which is collected in a number of fractions, and a residue;
• separately contacting each collected fraction of the distillate and the residue with a separate extraction agent capable of extracting nitrogen-containing compounds from the collected fractions and residue, for a time sufficient to form, for each fraction and for the residue, a nitrogen-lean raffinate and a corresponding nitrogen-rich extract;
• and
• separating each nitrogen-lean raffinate from the corresponding nitrogen-rich extract.

A process for reducing the nitrogen content of shale oil containing nitrogen-containing compounds comprising:

• introducing shale oil to a distillation zone wherein the shale oil is distilled sufficiently to form a distillate and a bottoms;
• contacting, in a first extraction zone, the distillate with a first extraction agent capable of selectively extracting nitrogen-containing compounds from the distillate for a time sufficient to form a first nitrogen-lean raffinate having no more than about 3,000 ppm nitrogen and a first nitrogen-rich extract;
• separating the first nitrogen-lean raffinate from the first nitrogen-extract;
• contacting, in a second extraction zone, the bottoms with a second extraction agent capable of selectively extracting nitrogen-containing compounds from the bottoms for a time sufficient to form a second nitrogen-lean raffinate and a second nitrogen-rich extract;
• separating the second nitrogen-lean raffinate from the second nitrogen-rich extract;
• and
• hydrotreating the second nitrogen-lean raffinate to further reduce the nitrogen content of the second nitrogen-lean raffinate.

A process for upgrading shale oil comprising:

• distilling a shale oil feed containing nitrogen-containing compounds to form a distillate and a bottoms;
• contacting the distillate with a first extraction agent capable of selectively extracting nitrogen-containing compounds from the distillate for a time sufficient to form a first nitrogen-lean raffinate and a first nitrogen-rich extract comprising the first extraction agent and nitrogen-containing compounds;
• separating the first nitrogen-lean raffinate from the first nitrogen-rich extract;
• removing at least a portion of the first extraction agent from the first nitrogen-rich extract to thereby form a first high-nitrogen extract oil;
• contacting the bottoms with a second extraction agent capable of selectively extracting nitrogen-containing compounds from the bottoms for a time sufficient to form a second nitrogen-lean raffinate and a second nitrogen-rich extract comprising the second extraction agent and nitrogen-containing compounds;
• separating the second nitrogen-lean raffinate from the second nitrogen-rich extract;
• removing at least a portion of the second extraction agent from the second nitrogen-rich extract to thereby form a second high nitrogen extract oil;
• and
• hydrotreating the second nitrogen-lean raffinate to further reduce the nitrogen content of the second nitrogen-lean raffinate.

A process for reducing the nitrogen content of shale oil comprising:

• distilling shale oil containing nitrogen-containing compounds to form a shale oil distillate containing nitrogen-containing compounds and a bottoms containing nitrogen-containing compounds;
• introducing the shale oil distillate to a first extraction zone containing a first aqueous solvent comprising an organic acid component selected from the group consisting of acetic acid, formic acid and mixtures thereof, and contacting the shale oil distillate with said first aqueous solvent for a time sufficient to form a first nitrogen-lean raffinate and a first nitrogen-rich extract comprising the first aqueous solvent and nitrogen-containing compounds;
• separating the first nitrogen-lean raffinate from the first nitrogen-rich extract;
• distilling the first nitrogen-rich extract to form a first solvent distillate comprising at least a portion of the organic acid component substantially free of nitrogen-containing compounds and a residue forming a first high-nitrogen extract oil;
• introducing the bottoms to a second extraction zone containing a second aqueous solvent comprising an organic acid component selected from the group consisting of acetic acid, formic acid and mixtures thereof, and contacting said bottoms with said second aqueous solvent for a time sufficient to form a second nitrogen-lean raffinate and a second nitrogen-rich extract comprising the second aqueous solvent and nitrogen-containing compounds;
• separating the second nitrogen-lean raffinate from the second nitrogen-rich extract;
• distilling the second nitrogen-rich extract to form a second solvent distillate comprising at least a portion of the organic acid component of the second aqueous solvent substantially free of nitrogen-containing compounds and a residue forming a second nitrogen extract oil;
• hydrotreating the second nitrogen-lean raffinate sufficiently to reduce the nitrogen content of the second nitrogen-lean raffinate to about the nitrogen content of the first nitrogen-lean raffinate;
• and
• combining the hydrotreated second nitrogen-lean raffinate with the first nitrogen-lean raffinate.

A process for upgrading a shale oil feed containing lighter shale oil compounds including lighter shale oil compounds containing nitrogen and heavier shale oil compounds including heavier shale oil compounds containing nitrogen comprising the steps of:

• heating the shale oil feed sufficiently to vaporize lighter shale oil compounds;
• condensing the vaporized lighter shale oil compounds in a number of consecutively collected fractions;
• separately reducing the nitrogen content of each collected fraction by the steps of:
• mixing the collected fraction with an extraction agent capable of selectively extracting lighter shale oil compounds containing nitrogen from the collected fraction for a time sufficient to form a nitrogen-rich extract comprising the extraction agent and vaporized shale oil compounds containing nitrogen and a nitrogen-lean raffinate containing vaporized shale oil compounds;
• and
• separating the raffinate containing vaporized shale oil compounds from the extract comprising vaporized shale oil compounds containing nitrogen;
• reducing the nitrogen content of the unvaporized shale oil by the steps of:
• mixing the unvaporized shale oil with an extraction agent capable of selectively extracting heavier shale oil compounds containing nitrogen from the unvaporized shale oil compounds for a time sufficient to form a nitrogen-rich extract comprising the extraction agent and unvaporized shale oil compounds containing nitrogen and a nitrogen-lean raffinate containing unvaporized shale oil compounds;
• and
• separating the raffinate containing unvaporized shale oil compounds from the extract comprising unvaporized shale oil compounds containing nitrogen;
• hydrotreating the raffinate containing unvaporized shale oil compounds to further reduce its nitrogen content;
• combining the raffinates containing vaporized shale oil compounds and the hydrotreated raffinate containing unvaporized shale oil compounds to form a combined nitrogen-lean raffinate.