PROCESS FOR PRODUCTION OF TRANSPORTATION FUEL

Abstract

A process and a process plant for production of a hydrocarbon composition useful as a transportation fuel from a hydrocarbonaceous feedstock, including the steps of a. directing a hydrocarbonaceous feedstock to hydrotreatment in one or more steps providing an intermediate product including less than 0.1 wt % oxygen and a specific gravity, for the fraction boiling in the range defined by the commercial transportation fuel specification, above the upper limit of specific gravity under the commercial transportation fuel specification, b. providing a hydrotreated hydrocarbon stream for hydroconversion from the intermediate product, wherein a fraction for hydroconversion has a T50 being below T95 of the commercial transportation fuel specification, c. directing the stream for hydroconversion to contact a hydroconversion catalyst under hydroconversion conditions to provide a hydroconverted hydrocarbon stream, d. fractionating said hydroconverted hydrocarbon stream to provide at least said hydrocarbon composition useful as a transportation fuel.

Claims

1. A process for production of a hydrocarbon composition useful as a transportation fuel according to a commercial transportation fuel specification from a hydrocarbonaceous feedstock comprising at least 0.5 wt % oxygen and at least 25 wt % carbon in cyclic structures, comprising the steps of a. directing a hydrocarbonaceous feedstock to hydrotreatment in one or more steps providing an intermediate product comprising less than 0.1 wt % oxygen and a specific gravity, for the fraction boiling in the range defined by the commercial transportation fuel specification, above the upper limit of specific gravity under the commercial transportation fuel specification, b. providing a hydrotreated hydrocarbon stream for hydroconversion from said intermediate product optionally by fractionation, wherein said fraction for hydroconversion has a T50 being below T95 of the commercial transportation fuel specification, C. directing the stream for hydroconversion to contact a hydroconversion catalyst under hydroconversion conditions to provide a hydroconverted hydrocarbon stream, d. fractionating said hydroconverted hydrocarbon stream to provide at least said hydrocarbon composition useful as a transportation fuel.

2. The process according to claim 1, wherein fractionating said hydroconverted hydrocarbon stream further provides at least a fraction boiling above T95 of the commercial transportation fuel specification, which is directed as recycle to be combined with said hydrotreated hydrocarbon stream for hydroconversion.

3. The process according to claim 1, wherein the hydroconversion conditions involves a pressure above 15 MPa and below 25 MPa.

4. The process according to claim 1, wherein the hydroconversion conditions involves a temperature above 350 C. and below 420 C.

5. The process according to claim 1, wherein the hydroconversion catalyst comprises an active metal, either one or more elemental noble metals or one or more sulfided base metals, an acidic support.

6. The process according to claim 1, wherein at least one step of hydrotreatment is carried outside a fixed bed reactor.

7. The process according to claim 1, wherein at said commercial transportation fuel specification is a diesel specification.

8. The process according to claim 1, wherein the provision of a hydrotreated hydrocarbon stream for hydroconversion from said intermediate product by fractionation involves separating said intermediate product into a fraction boiling in the naphtha range and a fraction boiling above the naphtha range.

9. The process according to claim 1, wherein the hydrocarbonaceous feedstock originates from a thermochemical decomposition process.

10. The process plant for production of a hydrocarbon by a process according to claim 1.

Description

DESCRIPTION OF DRAWINGS

[0046] FIG. 1 shows a process for conversion of solid material to transportation fuel. A solid feedstock (2) such as end of life tires or ligneous waste (straw, wood or similar) is directed to a hydrothermal decomposition plant (PYP), which may be of several different types. In the illustration, solids (4) such as char and carbon black, pyrolysis gas (6) and pyrolysis oil (8) are released from the hydrothermal decomposition plant (PYP), but not all fractions may be present. Commonly the pyrolysis oil is only formed after cooling a vapor phase from the pyrolysis process. In addition to pyrolysis oil, water may also be condensed from the vapor phase. Integrated in the pyrolysis process, a hydrotreatment process may also be carried out in which the pyrolysis vapor or the pyrolysis oil is contacted with hydrogen in the presence of a hydrotreatment catalyst, e.g. in a process where the catalyst is fluidized. A step of hydrotreatment (HDT) is carried out in order to provide a hydrotreated intermediate after combination of a hydrogen rich stream (10) and the pyrolysis oil (8), in the presence of a hydrotreatment catalyst (HDT) comprising one or more metals typically sulfided base metals, but possibly noble metals, on a refractory support such as alumina. Here this step is shown as a single fixed bed reactor (HDT), but the step may in practice involve multiple reactors, local recycle of intermediate product, splitting of the feed between multiple and other variations known e.g. from the treatment of renewable fats and oils and/or fossil feedstocks.

[0047] The hydrotreated intermediate (12) is directed to a first fractionation step (FRAC1), in which gas (14), naphtha (16), diesel (17) and high boiling hydrotreated hydrocarbons (18) are separated, and the diesel (17) and the high boiling hydrotreated hydrocarbon (18) are combined with a recycle heavy product (20) and directed as a stream for hydroconversion (22) to further hydroprocessing in a hydroconversion reactor (HC), where it contacts a hydroconversion catalyst, comprising an active metal, which may either be a sulfided base metal or a noble metal, and an acidic support, such as a zeolite. The hydroconversion produces a hydroconverted hydrocarbon stream (24), by saturating aromatics and breaking carbon-carbon bond to open hydrocarbon rings, with a side effect of reducing molecular weight by cleaving some molecules. Accordingly, the amount of cyclic compounds is reduced and the boiling point range of the hydroconverted hydrocarbon stream (24) is changed with a reduction of the amount of middle distillate, such as jet and diesel, and a provision of naphtha and fuel gases, which are separated in a second fractionation step (FRAC2), into gas (26), naphtha (28), diesel (30) and recycle heavy product (20). The naphtha produced during hydroconversion (28) will be paraffinic and thus have a lower octane number, and may therefore be preferred to be directed to a hydrogen plant, to provide the hydrogen for the process. Since the high boiling hydrotreated hydrocarbons (18) were fractionated to include an amount boiling above the middle distillate boiling range, an amount of such heavy product is likely to be present for recycle to the inlet of the hydroconversion reactor.

[0048] FIG. 1 was made to illustrate the principles of the process, and for simplicity details have been omitted, including heat exchangers, the gas loop and phase separators.

[0049] In an alternative embodiment, the entire hydrotreated intermediate (12) may in combination with the recycle heavy product (20) be directed as the stream for hydroconversion (24).

DESCRIPTION OF EMBODIMENTS

[0050] Multiple aspects of the disclosed invention exists.

[0051] A first aspect of the present disclosure relates to a process for production of a hydrocarbon composition useful as a transportation fuel according to a commercial transportation fuel specification from a hydrocarbonaceous feedstock comprising at least 0.5 wt % oxygen and at least 25 wt % carbon in cyclic structures, comprising the steps of [0052] a. directing a hydrocarbonaceous feedstock to hydrotreatment in one or more steps providing an intermediate product comprising less than 0.1 wt % oxygen and a specific gravity, for the fraction boiling in the range defined by the commercial transportation fuel specification, above the upper limit of specific gravity under the commercial transportation fuel specification, [0053] b. providing a hydrotreated hydrocarbon stream for hydroconversion from said intermediate product optionally by fractionation, wherein said fraction for hydroconversion has a T50 being below T95 of the commercial transportation fuel specification, [0054] c. directing the stream for hydroconversion to contact a hydroconversion catalyst under hydroconversion conditions to provide a hydroconverted hydrocarbon stream, [0055] d. fractionating said hydroconverted hydrocarbon stream to provide at least said hydrocarbon composition useful as a transportation fuel.

[0056] This has the associated benefit of providing a cost effective process for production of transportation fuels from a cyclic aromatic feedstock.

[0057] A second aspect of the process according to the first aspect, wherein fractionating said hydroconverted hydrocarbon stream further provides at least a fraction boiling above T95 of the commercial transportation fuel fuel specification, which is directed as recycle to be combined with said hydrotreated hydrocarbon stream for hydroconversion.

[0058] This has the associated benefit of also converting high boiling feedstock to transportation fuel.

[0059] A third aspect of the process according to the first or second aspects, wherein the hydroconversion conditions involves a pressure above 15 MPa and below 25 MPa.

[0060] This has the associated benefit of such elevated pressure favoring addition of hydrogen for saturation of aromatics and opening of cyclic structures.

[0061] A fourth aspect of the process according to any aspect above, wherein the hydroconversion conditions involves a temperature above 350 C. and below 420 C.

[0062] This has the associated benefit of providing severe conditions, supporting high reactivity.

[0063] A fifth aspect of the process according to any aspect above, wherein the hydroconversion catalyst comprises an active metal, either one or more elemental noble metals such as platinum and/or palladium or one or more sulfided base metals such as nickel, cobalt, tungsten or molybdenum, an acidic support, such as a molecular sieve showing high activity in breaking carbon-carbon bonds, and having a topology such as MFI, BEA and FAU or amorphous silica-alumina and optionally a refractory support such as alumina, silica or titania, or combinations thereof.

[0064] This has the associated benefit of such a material being active in hydroconversion reactions, where the carbon-carbon bonds are broken and molecular structure is changed.

[0065] A sixth aspect of the process according to any aspect above, wherein at least one step of hydrotreatment is carried out outside a fixed bed reactor.

[0066] This has the associated benefit of enabling a process of hydrotreatment in close coupling with an upstream thermochemical conversion process.

[0067] A seventh aspect of the process according to any aspect above, wherein at said commercial transportation fuel specification is a diesel specification, such as European Standard, EN590.

[0068] This has the associated benefit of a diesel fuel having a large overlap of boiling point range with a feedstock originating from thermochemical conversion.

[0069] An eighth aspect of the process according to any aspect above, wherein the provision of a hydrotreated hydrocarbon stream for hydroconversion from said intermediate product by fractionation involves separating said intermediate product into a fraction boiling in the naphtha range and a fraction boiling above the naphtha range.

[0070] This has the associated benefit of enabling avoiding hydroconversion of the fraction boiling in the naphtha range, which would reduce the octane number of this fraction.

[0071] A ninth aspect of the process according to any aspect above, wherein the hydrocarbonaceous feedstock originates from a thermochemical decomposition process.

[0072] This has the associated benefit of enabling upgrading of such a hydrocarbonaceous feedstock from a thermochemical decomposition process, which may be especially useful if it comprises high amounts of cyclic structures from the material directed to the thermochemical decomposition process, as would be the case from end of life tires and ligneous materials.

[0073] An additional aspect of the invention relates to a process plant for production of a hydrocarbon by a process according to any aspect above.

EXAMPLES

[0074] A process illustrating FIG. 1 is evaluated with basis in experiments, in combination with evaluations of process simulations.

[0075] Case 1 illustrated in Table 1 represents the process layout according to FIG. 1, but taking out heavy product 20 instead of recycling it, for simplicity. Here a pyrolysis oil originating from pyrolysis of end of life tires (stream 8) is hydrotreated, separated in naphtha and a higher boiling fraction and directed to contact a hydroconversion catalyst under conditions resulting in a diesel product comprising a low amount of aromatics and a specific gravity value in compliance with EN590 requirements (0.8391 vs. the specified 0.845). The severity of the conditions is illustrated by the conversion of the fraction boiling above 390 C., of which 73.5 wt % is converted to lower boiling product.

[0076] Stream 16 is a fraction of aromatic naphtha corresponding to 15 wt % FF (wt % on fresh feed basis). In addition, 16 wt % FF naphtha with 8.3 wt % aromatics is produced in stream 28, and in stream 30 62 wt % FF diesel with 4.0 wt % aromatics is produced. In addition, 6.1 wt % FF is available as unconverted oil, which could be directed as recycle.

[0077] Case 2 illustrated in Table 2 similarly represents a variant of the process layout according to FIG. 1 in which all of the hydrotreated product 12 is directed to hydrocracking. The severity of the conditions is illustrated by the conversion of the fraction boiling above 390 C. In this case 56.5 wt % is converted to lower boiling product. For practical reasons the experiments were carried out with only the liquid fraction of the hydrotreated product 12 being directed to hydrocracking.

[0078] Here 66 wt % FF diesel is produced, which has a specific gravity slightly above the EN590 requirements (0.8468 vs. the specified 0.845). Even if slightly more severe conditions were chosen, the diesel yield would be expected to be around 64 wt % FF, i.e. slightly above that shown in Table 1.

[0079] With respect to naphtha only 24 wt % FF is produced, with 13 wt % aromatics, which is about half the amount, with a low aromatics content.

[0080] Finally, case 3 illustrated in Table 3 represents a situation where the intermediate fractionation provides naphtha and diesel and hydroconversion is operated as hydrocracking in order to maximize liquid yields. This case shows a total of 76.5 wt % diesel and 18.1 wt % naphtha, which is slightly higher combined yield of product boiling in the diesel and naphtha ranges compared to case 1 or 2, but the 62 wt % FF diesel product does not fulfill specific gravity specifications, and will therefore introduce limitations on use, even in blends.

[0081] In summary, the results show that for case 1, with hydroconversion of the fraction boiling in the diesel range and above, a fraction of diesel is provided in compliance with specific gravity requirements. In addition, two naphtha streams are provided; one with high aromatic content (and thus high octane number) and one with low aromatic content.

[0082] For case 2, the amount and quality of the diesel fraction is above that of case 1, but only a single naphtha fraction is provided. The naphtha has a low content of aromatics, and the quantity is below that of case 1.

[0083] For case 3, it is seen that a higher amount of diesel and naphtha may be obtained, but that the diesel fraction has very poor specific gravity value, and thus only has a limited value as diesel blendstock. Furthermore, the density being almost 4% above the specification also has the consequence that the volume for the same mass is 4% lower, so the loss of mass is to some extent compensated by an increase of volume.

TABLE-US-00001 TABLE 1 8 12 16 18 24 28 30 20 C1-4 [wt % FF] 0 1.1 2.0 C5-150 C. [wt % FF] 13 15 15 16 16 150-390 C. [wt % FF] 55 62 85 62 62 >390 C. [wt % FF] 32 23 6.1 6.1 Aromatics [wt %] 49 35 41 27 4.1 8.3 4.0 3.6 Naphthenes [wt %] 3.6 38 43 29 36 72 35 31 Oxygen [wt %] 1.2 ND ND ND ND ND ND ND SG 0.9348 0.8808 0.7941 0.8955 0.8290 0.7624 0.8391 0.8855

TABLE-US-00002 TABLE 2 8 12 24 28 30 20 C1-4 [wt % FF] 0 1.1 1.5 C5-150 [wt % FF] 13 15 24 24 150-390 [wt % FF] 55 62 66 66 >390 [wt % FF] 32 23 10 10 Aromatics [wt %] 49 35 7.0 13 7.0 3.4 Naphthenes [wt %] 3.6 38 38 71 38 19 Oxygen [wt %] 1.2 ND ND ND ND ND SG 0.9348 0.8808 0.8346 0.7704 0.8468 0.8988

TABLE-US-00003 TABLE 3 8 12 16 17 18 24 28 30 20 C1-4 [wt % FF] 0 1.1 1.0 C5-150 [wt % FF] 13 15 15 3.1 3.1 150-390 [wt % FF] 55 62 62 14.5 14.5 >390 [wt % FF] 32 23 23 2.3 2.3 Aromatics [wt %] 49 35 41 32 39 2.6 5 2 3.2 Naphthenes [wt %] 3.6 38 43 38 35 40 75 35 25 Oxygen [wt %] 1.2 ND ND ND ND ND ND ND ND SG 0.9348 0.8808 0.7941 0.8780 0.9530 0.8350 0.7700 0.8450 0.8750