METHOD FOR PRODUCTION OF A TRANSPORTATION FUEL

Abstract

The present disclosure relates to a process for production of a hydrocarbon fraction from an oxygenate feedstock, comprising the steps of providing a process feed comprising an amount of an ammonia precursor, hydrogen and an amount of oxygenates at a temperature above 200? C., directing said process feed to contact a material catalytically active in hydrodeoxygenation (HDO) under hydrotreating conditions to provide a hydrodeoxygenated intermediate product, wherein said ammonia precursor provides an amount of ammonia corresponding to a partial pressure of NH.sub.3 in the presence of said material catalytically active in hydrodeoxygenation being at least 0.1 mbar, This has the associated benefit that the ammonia precursor releases ammonia by thermal reaction, such that the presence of ammonia may limit the extent of formation of high boiling product in the hydrodeoxygenation process.

Claims

1. A process for production of a hydrocarbon fraction from an oxygenate feedstock, comprising the steps of providing a process feed comprising an amount of an ammonia precursor, hydrogen and an amount of said oxygenate feedstock, at a temperature above 200? C., directing said process feed to contact a material catalytically active in hydrodeoxygenation (HDO) under hydrotreating conditions to provide a hydrodeoxygenated intermediate product, wherein said ammonia precursor provides an amount of ammonia corresponding to a partial pressure of NH3 in the presence of said material catalytically active in hydrodeoxygenation being at least 0.1 mbar and less than 20 mbar.

2. The process according to claim 1 wherein said partial pressure of NH3 is at least 0.5 mbar and less than 10 mbar.

3. The process according to claim 1 wherein said oxygenate feedstock comprises at least 50 wt/wt % fatty acid esters or fatty acids.

4. The process according to claim 1 wherein said oxygenate feedstock comprises at least 20 wt/wt % aromatics.

5. The process according to claim 1, wherein at least an amount of said ammonia precursor is provided in a separate liquid ammonia precursor stream.

6. The process according to claim 1, wherein at least an amount of said liquid ammonia precursor stream comprises an aqueous ammonia solution, a solution of an aqueous ammonia salt, or an amine.

7. The process according to claim 1, wherein said liquid ammonia precursor stream comprises an amount of ammonium, ammonia or amine withdrawn from a downstream process position.

8. The process according to claim 1, wherein said liquid ammonia precursor stream has a pH below 8.

9. The process according to claim 1, further comprising one or more additional process steps taken from the group off hydrocracking, isomerization and hydrodearomatization of intermediate streams in the process.

10. The process according to claim 8, further comprising the step of separating one or more intermediate streams in a gas stream, an non-polar liquid stream and optionally an polar liquid stream prior to directing an amount of the non-polar stream to one or more of said additional process steps.

11. The process according to claim 10, wherein at least an amount of said gas stream, optionally after partial or full purification, is directed to be comprised in said process feed.

12. The process according to claim 10, wherein at least an amount of said polar liquid stream is directed to be comprised in said process feed.

13. (canceled)

14. A process plant comprising a means for provision of an ammonia precursor in a process feed and configured for carrying out the process according to claim 1.

Description

EXAMPLES

[0067] The effect of the present disclosure was evaluated by hydrotreating of a refined, deodorized and bleached soybean oil with a total acid number of 0.056 mg KOH/g. This acid number is very low, so the oil had no relevant need for neutralization. The soybean oil feedstock is further characterized in Table 1.

[0068] Hydrotreatment was carried out in a once-through pilot plant consisting of one reactor loaded with HDO catalysts. The HDO was carried out at LHSV 0.5, temperature 290-295 C and 50-65 barg pressure.

[0069] Pure hydrogen was used as treat gas while dibutylamine (DBA), in a range corresponding to 0-45 ppm.sub.wt elemental nitrogen, and dipropyl-disulfide (DPDS), corresponding to 340 ppm.sub.wt elemental sulfur, was added to the liquid feed. DBA and DPDS decompose to NH.sub.3 and H.sub.2S respectively in presence of H.sub.2 at elevated temperatures, thus at the reactor inlet the gas feed consists of hydrogen, H.sub.2S and NH.sub.3. NH.sub.3. A summary of the experimental data can be found in Table 2.

[0070] A stacked bed of two hydrogenation catalyst were used in the experiment. The upper layer in the reactor, 60% vol of total, was a commercially available catalyst comprising 15 wt % sulfided molybdenum on an alumina carrier, while the bottom layer, 40% vol of total, was a commercial sulfided 3 wt % nickel and 15 wt % molybdenum catalyst on an alumina carrier. The experiment was carried out in down flow mode, thus the feed to the reactor met the upper layer of the catalyst first.

[0071] From Table 2 it is clearly seen that with increasing NH.sub.3 partial pressure, the amount of product boiling above 370? C. (the column % wt BP>370? C.)i.e. above C.sub.22H.sub.46 which boils at 369? C., decreases from 7.5 wt % at 0.15 mbar partial pressure to 3.9 wt % at 2.8 mbar partial pressure.

[0072] In a second example the effect of the present disclosure, for an acidic feedstock comprising organic nitrogen was evaluated by hydrotreating of a distiller's corn oil sample, which contains 70 ppm.sub.wt organic nitrogen. The TAN value for this sample was 25 mg KOH/g. The distillers corn oil is further characterized in Table 3.

[0073] Hydrotreatment was carried out in a once-through pilot plant consisting of one reactor loaded with HDO catalysts. The HDO was carried out at LHSV 0.5, temperature 290-295 C and 50-65 barg pressure.

[0074] Pure hydrogen was used as treat gas while dibutylamine (DBA), in a range corresponding to 0-45 ppm.sub.wt elemental nitrogen, and dipropyl-disulfide (DPDS), corresponding to 340 ppm.sub.wt elemental sulfur, was added to the liquid feed. DBA and DPDS decompose to NH.sub.3 and H.sub.2S respectively in presence of H.sub.2 at elevated temperatures, thus at the reactor inlet the gas feed consists of hydrogen, H.sub.2S and NH.sub.3. A summary of the experimental data can be found in Table 2.

[0075] A stacked bed of two hydrogenation catalyst were used in the experiment. The upper layer in the reactor, 60% vol of total, was a commercially available catalyst comprising 15 wt % sulfided molybdenum on an alumina carrier, while the bottom layer, 40% vol of total, was a commercial sulfided 3 wt % nickel and 15 wt % molybdenum catalyst on an alumina carrier. The experiment was carried out in down flow mode, thus the feed to the reactor met the upper layer of the catalyst first.

[0076] From Table 4 it is clearly seen that with increasing NH.sub.3 partial pressure, the amount of product boiling above 370? C. (the column % wt BP>370? C.) decreases from 8.9 wt % at 0 mbar partial pressure to 6.4 wt % at 3.0 mbar partial pressure. The highest addition of DBA 45 ppm.sub.wt would correspond to a theoretical maximum reduction of TAN of approximately 0.2 mg KOH/g, and therefore this is unlikely to be the cause of the effect, since the feedstock would still have a TAN value of 24.8 mg KOH/kg, and thus the expected effect of increased NH.sub.3 partial pressure from NH.sub.3 interaction with fatty acids, would be a relative reduction of polymerization corresponding to the relative reduction in reactive fatty acids by 0.8%, and not the observed reduction from 8.9 wt % to 6.4 wt % (i.e. 28% less heavy product). At addition corresponding to 20 mbar the expected relative effect from direct interaction with the feedstock would start to be significant, since this would correspond to neutralization of 5-6% of the fatty acids, and therefore the surprising effect assumed to be caused by catalyst moderation is not considered significant above this limit.

[0077] A comparison of Table 2 and Table 4 shows that in both cases a formation of heavy product is happening, as evidenced by the presence of 3.9 wt % to 8.5 wt % boiling above 370? C., contrary to the 0.3 wt % present in the feedstock. However, this formation is clearly reduced by the presence of NH.sub.3. The effect of NH.sub.3 partial pressure is similar for a non-acidic, nitrogen depleted feedstock and an acidic feedstock comprising organic nitrogen. This confirms the effect of a moderate NH.sub.3 partial pressure at the catalyst bed inlet upon limiting the formation of heavy product during hydrodeoxygenation, and that this effect is not obtained from the presence of organic nitrogen.

TABLE-US-00001 TABLE 1 Property Unit Method Value N wt ppm D 4629 <1 S wt ppm D 7039 <1 H wt % D 7171 11.55 C16 wt % 11.0 C18 wt % 87.5 C20 wt % 0.7 C22 wt % 0.4 C24 wt % 0.3 TAN mg KOH/g 0.06

TABLE-US-00002 TABLE 2 Total Temp Pressure LHSV H2/oil p.sub.NH3 % wt [C.] [barg] [1/h] [NI/I] [mbar] BP > 370? C. 295 50 0.5 1500 0.15 7.5 290 50 0.5 1500 1.0 5.9 290 50 0.5 1500 2.2 5.2 290 56 0.5 1500 2.4 4.7 290 56 0.5 1500 2.4 4.9 290 65 0.5 1500 2.8 3.9

TABLE-US-00003 TABLE 3 Property Unit Method Value N wt ppm D 4629 70 S wt ppm D 7039 17 H wt % D 7171 11.59 C16 wt % 12.4 C18 wt % 85.4 C20 wt % 0.7 C22 wt % 0.0 C24 wt % 0.3 TAN mg KOH/g 0.06

TABLE-US-00004 TABLE 4 Total Temp Pressure LHSV H2/oil p.sub.NH3 % wt [C.] [barg] [1/h] [NI/I] [mbar] BP > 370? C. 300 50 0.5 1500 0.0 8.9 296 50 0.5 1500 0.0 8.7 291 50 0.5 1500 0.0 8.3 291 50 0.5 1500 1.0 8.1 291 50 0.5 1500 2.4 7.4 290 50 0.5 1500 2.4 7.5 290 56 0.5 1500 2.6 7.0 290 65 0.5 1500 3.0 6.4