PROCESS AND PLANT FOR PRODUCING HYDROCARBONS WITH REDUCED CO2-FOOTPRINT AND IMPROVED HYDROGEN INTEGRATION

Abstract

Process and plant for producing hydrocarbon products from a feedstock originating from a renewable source, where a hydrogen-rich stream and on off-gas stream comprising hydrocarbons is formed. A portion of the hydrogen-rich stream is used as a recycle gas stream in a hydroprocessing stage for the production of said hydrocarbon products, and another portion may be used for hydrogen production, while the off-gas stream is treated to remove its H.sub.2S content and used as a recycle gas stream in the hydrogen producing unit, from which the hydrogen produced i.e. make-up hydrogen, is used in the hydroprocessing stage. The invention enables minimizing natural gas consumption in the hydrogen producing unit as well as steam reformer size.

Claims

1. A process for producing a hydrocarbon product, said process comprising the steps of: i) passing a feedstock originating from a renewable source through a hydroprocessing stage for producing a main hydrotrotreated stream; ii) passing the main hydrotreated stream to a separation stage for producing: an aqueous stream, a hydrogen-rich stream as a first recycle gas stream, an off-gas stream comprising hydrocarbons, and said hydrocarbon product, boiling at above 50° C.; iii) passing the first recycle gas stream to the hydroprocessing stage; iv) passing the off-gas stream as a second recycle gas stream to a hydrogen producing unit for producing a hydrogen stream as a make-up hydrogen stream; and v) passing the make-up hydrogen stream to the hydroprocessing stage; wherein prior to conducting step iv), said off-gas stream passes to a separation stage for removing H.sub.2S and thereby producing said second recycle gas stream.

2. Process according to claim 1, wherein the process further comprises: vi) splitting said hydrogen-rich stream into said first recycle gas stream and a third recycle gas stream, and passing said third recycle gas stream to said hydrogen producing unit.

3. Process according to claim 1, wherein in step i) the hydroprocessing stage comprises: i-1) passing the feedstock through a first catalytic hydrotreating unit under the addition of hydrogen for producing a first hydrotreated stream; and i-2) passing the first hydrotreated stream to a dewaxing section comprising a second catalytic hydrotreating unit under the addition of hydrogen for producing said main hydrotreated stream.

4. Process according to claim 3, wherein between step i-1) and i-2) the process further comprises passing the first hydrotreated stream to a separator, for removing H.sub.2S, NH.sub.3, and H.sub.2O, thereby producing said first hydrotreated stream.

5. Process according to claim 1, wherein in step ii) the separation stage comprises: ii-1) passing the main hydrotreated stream to a separator for producing said aqueous stream, said hydrogen-rich stream, and a heavy hydrocarbon stream; and ii-2) passing the heavy hydrocarbon stream to a fractionation section for producing said off-gas stream, and said hydrocarbon product.

6. Process according to claim 3, wherein in step v) the make-up hydrogen stream passes to at least one of: said first catalytic hydrotreating unit; said a separator between step i-1) and i-2), second catalytic hydrotreating unit; and an additional catalytic hydrotreating unit.

7. Process according to claim 1, wherein the hydrogen producing unit comprises feeding: said second recycle gas stream, and a hydrocarbon feedstock with one or more of said hydrocarbon products.

8. Process according to claim 1, wherein the hydrogen producing unit comprises subjecting the hydrocarbon feedstock to: cleaning in a cleaning unit; catalytic steam methane reforming in a steam reforming unit; water gas shift conversion in a water gas shift unit and hydrogen purification in a hydrogen purification unit.

9. Process according to claim 8, wherein said second recycle gas stream is fed to the cleaning unit.

10. Process according to claim 2, wherein the hydrogen-rich stream, or first recycle stream, or third recycle stream comprises hydrogen in a concentration of 50 vol % or higher, and wherein any of said streams is passed through a hydrogen purification unit: prior to splitting said hydrogen-rich stream into a first recycle stream or a third recycle stream, or prior to passing the first recycle stream to the hydroprocessing stage, or prior to passing said third recycle stream to the hydrogen producing unit.

11. Process according to claim 9, wherein the hydrogen purification unit is the hydrogen purification unit of the hydrogen producing unit, and said third recycle stream is passed through this hydrogen purification unit.

12. Process according to claim 11, wherein the hydrogen purification unit is a Pressure Swing Adsorption unit (PSA unit), said PSA unit producing an off-gas stream which is used as fuel in the steam reforming unit of the hydrogen producing unit, and/or in fired heaters in any of the catalytic hydrotreating units of the hydroprocessing stage, separation units of the separation stage, and/or for steam production.

13. Process according to claim 9, wherein the steam reforming unit is: a convection reformer, a tubular reformer, autothermal reformer (ATR), electrically heated steam methane reformer (e-SMR), or any combinations thereof.

14. Process according to claim 1, wherein prior to passing the make-up hydrogen stream to the hydroprocessing stage, the make-up hydrogen stream passes through a compressor section comprising a make-up compressor, the make-up compressor also producing a hydrogen recycle stream which is added to the hydrogen producing unit.

15. Process according to claim 1, wherein the feedstock is obtained from a raw material of renewable origin originating from plants, algae, animals, fish, vegetable oil refining, domestic waste, waste rich in plastic, industrial organic waste, or a feedstock derived from one or more oxygenates taken from the group consisting of triglycerides, fatty acids, resin acids, ketones, aldehydes or alcohols where said oxygenates originate from one or more of a biological source, a gasification process, a pyrolysis process, Fischer-Tropsch synthesis, or methanol based synthesis.

16. Process according to claim 1, wherein step i) also comprises adding a feedstock originating from a fossil fuel source, such as diesel, kerosene, naphtha, and vacuum gas oil (VGO), and/or recycling a hydrocarbon product.

17. Plant for producing a hydrocarbon product, comprising: a hydroprocessing section arranged to receive a feedstock originating from a renewable source and a compressed hydrogen-rich feed stream for producing a main hydrotreated stream; a separation section arranged to receive said main hydrotreated stream for producing an aqueous stream, a hydrogen-rich stream as a first recycle gas stream, an off-gas stream comprising hydrocarbons as a second recycle stream, and said hydrocarbon product, boiling at above 50° C.; a separation section for removing H.sub.2S and thereby producing said second recycle gas stream; a hydrogen producing unit (HPU) arranged to receive said second recycle gas stream and a hydrocarbon feedstock for producing a make-up hydrogen stream; a compressor section arranged to receive said first recycle gas stream and at least a portion of the make-up hydrogen stream produced in said HPU, for generating said compressed hydrogen-rich feed stream and a make-up hydrogen recycle stream; and a conduit for passing said first recycle gas stream to said compressor section; a conduit for passing said make-up hydrogen stream from the HPU to said compressor section.

18. The process according to claim 1, wherein the separation stage is at least one of an amine absorption stage, a caustic scrubber, and a sulfur absorbent.

19. The process according to claim 4, wherein said separator is a high-pressure separator or a low-pressure separator; and wherein the step of passing the first hydrotreated stream to said separator further produces a vapor stream, and a recycle oil stream.

20. The process of claim 5, wherein said separator is a cold separator.

21. The process of claim 7, wherein the hydrocarbon feedstock comprises natural gas, and wherein said hydrocarbon products comprises naphtha.

22. The process of claim 8, wherein said cleaning unit is a sulfur-chlorine-metal absorption or catalytic unit.

23. The process of claim 8, further comprising at least one of the steps of: prereforming in a pre-reforming unit; and carbon dioxide removal in a CO.sub.2-separator unit.

24. The process of claim 14, wherein the hydrogen recycle stream from the make-up compressor is added directly to the second recycle stream entering the hydrogen producing unit, and/or to the cleaning unit of the hydrogen producing unit.

25. The process of claim 1, wherein the first recycle gas stream is not subjected to a separation stage for removing H.sub.2S and/or CO.sub.2, prior to being passed to the hydroprocessing stage.

26. The process of claim 25, wherein the first recycle gas stream is not subjected to a separation stage for removing NH.sub.3 and/or CO, prior to being passed to the hydroprocessing stage.

27. Process according to claim 25, wherein in step ii) the separation stage comprises: ii-1) passing the main hydrotreated stream to a cold separator, for producing said aqueous stream, said hydrogen-rich stream, and a heavy hydrocarbon stream; and ii-2) passing the heavy hydrocarbon stream to a fractionation section for producing said off-gas stream, and said hydrocarbon product.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0107] FIG. 1 shows a schematic flow diagram of the overall process/plant, i.e. integrated process/plant, according to a specific embodiment of the invention.

[0108] FIG. 2 shows a schematic flow diagram of the overall process/plant according to another specific embodiment of the invention.

DETAILED DESCRIPTION

[0109] With reference to FIG. 1, a block flow diagram of the overall process/plant 10 is shown, where renewable feed 12 such as soy oil, rapeseed oil, or used cooked oil is fed to the hydroprocessing stage 110. This stage or section comprises a feed section and reactor section including HDO, HDW and optionally also HCR (hydrocracking) units, for producing a main hydrotreated stream 14, which is then passed to separation stage 120 which produces: aqueous (water) stream 16; hydrogen-rich stream 18 preferably having 50% vol. H.sub.2 or more, light hydrocarbons, H.sub.2S, CO and CO.sub.2; off-gas stream 20 comprising hydrocarbons such as light hydrocarbon stream, also comprising NH.sub.3, CO, CO.sub.2 and H.sub.2S and optionally also hydrogen not consumed in the hydrotreating unit(s) as soluble hydrogen in hydrocarbon phase; and hydrocarbon products in the form of renewable diesel 22, renewable jet fuel 24 and renewable naphtha 26. The hydrogen-rich stream 18 is split to form a first recycle stream 28, while the off-gas stream 20 passes to a H.sub.2S removal stage 130 to form a treated off-gas stream in the form of second recycle stream 32, which is then used as feed for the hydrogen producing unit 140, together with the produced renewable product, e.g. renewable naphtha 26. A third recycle gas stream 30 is formed by splitting the hydrogen-rich stream 18. The first recycle stream 28 being sent to hydroprocessing stage 110 does not include the use of a separation section for removing H.sub.2S and/or carbon oxides (CO, CO.sub.2).

[0110] The hydrogen producing unit 140 comprises a first section 142 which includes a cleaning unit such as sulfur-chlorine-metal absorption or catalytic unit, one or more pre-reformer units, steam reformer preferably a convection reformer (HTCR), and water gas shifting unit(s), as it is well known in the art of hydrogen production; none of these units are shown here. A hydrogen purification unit, such as PSA unit 144, is provided to further enrich the gas and produce a make-up hydrogen stream 36. This PSA-unit is also used to purify the third recycle gas stream 30. Off-gas 38 from the PSA unit (PSA offgas) is used as fuel in the hydrogen producing unit, and in particular as fuel for a HTCR unit, more particularly the burner of the HTCR unit, as well as in the hydroprocessing stage 110. A hydrocarbon feedstock in the form of natural gas stream 34 is used as make-up gas for the steam reforming in the hydrogen producing unit 140, 142.

[0111] The first recycle gas stream 28 passes to a compressor section 150 which includes a recycle compressor and make-up gas compressor, not shown. The first recycle gas stream 28 and make-up hydrogen stream 36 are then compressed by respectively the recycle compressor and the make-up compressor and used for adding hydrogen as stream 40 into the hydroprocessing stage 110. From the make-up compressor, a hydrogen stream 42 is recycled to hydrogen production unit 140, 142.

[0112] With reference to FIG. 2, another specific embodiment of the invention is presented, showing particular details of the different sections of in particular the hydroprocessing stage 110 and separation stage 120 of FIG. 1. Renewable feed 12 enters the feed section 112 of the hydroprocessing stage 110, where it is mixed with hydrogen stream 40′ from recycle compressor 152 as well as recycle oil 44 from a high pressure separator 116, such as a high pressure (HP) stripper, located downstream. The resulting renewable feed 12′ is fed to a first catalytic hydrotreating unit, here a HDO unit 114, wherefrom a first hydrotreated stream 12″ is withdrawn. This stream is then passed to the above high pressure separator 116 under the production of a vapor stream 46, recycle oil stream 44 and a liquid stream 12′″. The latter enters a dewaxing stage 118 comprising a second catalytic hydrotreating unit, here a HDW unit 118, for producing the main hydrotreated stream 14. A third catalytic hydrotreating unit in the form of a hydrocracking unit (HCR unit) may also be provided for instance downstream the HDO or HDW unit for producing the main hydrotreated stream 14. Such a hydrocracking unit may also be provided upstream the HDO unit, treating a recycle stream of heavy product in a so-called reverse staging layout. PSA off-gas stream 38 from the hydrogen producing unit 140 is suitably used as fuel in the dewaxing stage 118.

[0113] The main hydrotreated stream 14 may then be mixed with a wash-water stream 16″, which is separated from water stream 16 produced in the downstream separation stage 120. The separation stage 120 includes the use of a separator 122, preferably a cold separator, and a subsequent stripping section 124. Vapor 46 generated in the previous high-pressure separator 116 is used for the operation of separator 122. From the separator 122, hydrogen-rich stream 18 is withdrawn in the form of a first recycle gas stream rich in hydrogen, as well as the above-mentioned water stream 16, which is then divided in sour water stream 16′ and the wash-water stream 16″. From the separator 122 a heavy hydrocarbon stream 14′ preferably comprising C5-C30 hydrocarbons, H.sub.2, H.sub.2S, CO and CO.sub.2, is produced which is then fed to the stripping section 124 under the production of the off-gas stream 20 comprising hydrocarbons, as well as the renewable diesel 22 and renewable naphtha 26 as the hydrocarbon products.

[0114] The hydrogen production unit 140 includes, as in FIG. 1 a hydrogen purification unit, preferably a PSA-unit (not shown) from which an off-gas stream 38 containing CH.sub.4, H.sub.2, CO and CO.sub.2, is generated, and which is used as fuel in the process, not only in the hydrogen production plant itself, e.g. for the steam reforming unit, particularly a HTCR unit, but also in the hydroprocessing stage, in particular as shown here in the dewaxing section 118 therein. Accordingly, excess off-gas from the PSA not used in the hydrogen producing unit needs not to be burned off or flared.

[0115] The make-up hydrogen stream 36 is passed to the make-up compressor 154 of the compressor section 150. Compressed hydrogen stream 42 is recirculated to the hydrogen production unit 140, as well as to the hydroprocessing stage, particularly for the operation of the high pressure separator 116, HDW unit of dewaxing section 118 and optionally also the HDO unit 114, as compressed hydrogen stream 40. The first recycle gas stream 28 preferably comprising 50 wt % or more hydrogen is passed to a recycle compressor 152 of the compressor section 150, thereby producing another compressed hydrogen stream 40′ which is used in the hydroprocessing stage, particularly for the operation of the HDO unit 114.

[0116] The third recycle gas stream 30 also preferably comprising 50 wt % or more hydrogen and also hydrocarbons, is purified in a hydrogen purification unit, which can be arranged separately from the hydrogen producing unit. FIGS. 1 and 2 envisage, however, the preferred option where the hydrogen purification unit, preferably a PSA-unit, already being part of the hydrogen producing unit, is also used to enrich the third recycle gas stream 30 in hydrogen, thereby further improving the integration of the overall process/plant.

[0117] Off-gas stream 20 is treated in H.sub.2S removal unit 130, preferably in a low pressure amine absorber, in order to form a treated off-gas stream as second recycle gas stream 32 which is used as e.g. feed together with renewable naphtha 26 and hydrogen recycle 42 in the hydrogen producing unit 140.

EXAMPLES

Example 1

[0118] A process layout according to FIG. 2, yet without the use of a separator 116, i.e. so-called HydroFlex™ sour mode, was used for renewable diesel production. For hydrogen production a HTCR-unit together with a PSA-unit for hydrogen purification was used, as well as prereforming and water gas shift. A basis of 100 kg/hr renewable feedstock is applied.

[0119] In the HydroFlex™ sour mode, sour gases (H.sub.2S, and also NH.sub.3) are not removed in the hydroprocessing stage of the process. Renewable feedstock together with hydrogen is processed in a HDO unit followed by a dewaxing unit (DW unit) for producing e.g. renewable diesel and renewable jet fuel. In the following performance is presented start of run with a fresh catalyst, and end of run with a catalyst having been in operation close to its commercial lifetime.

[0120] Soy oil is used as renewable feedstock. The feed rate to the hydroprocessing reactor (HDO as hydrotreating unit) is thus 100 kg/hr. Make-up hydrogen gas rate from hydrogen production unit 3.1 kg/hr (SOR, start of run) and 3.8 kg/hr (EOR, end of run). Exit gas rate (purge gas rate from the separation stage), i.e. first light hydrocarbon stream (first recycle gas stream 18 in the figure), is 0.0 kg/hr (SOR), 1.4 kg/hr(EOR), and offgas rate, i.e. second light hydrocarbon stream (stream 20), is 7.2 kg/hr (SOR), 8.0 kg/hr (EOR). Natural gas (NG) (stream 34) requirement for the hydrogen producing unit is 3.87 kg/hr (SOR), 3.38 kg/hr (EOR).

[0121] The percentage reduction in NG-consumption compared with non-integrated unit, providing same hydrogen requirement for hydrotreater is 63% (SOR), 73% (EOR). This represents about 6-7% savings in the steam reformer (HTCR) compared to 100% natural gas case, i.e. using the non-integrated hydrogen producing unit based on 100% natural gas.

Example 2

[0122] A process layout according to FIG. 2, but with removal of sour gases in the hydroprocessing stage, so-called Hydroflex™ sweet mode unit, was used for renewable diesel production. For hydrogen production a HTCR-unit together with a PSA-unit for hydrogen purification was used, as well as prereforming and water gas shift. A basis of 100 kg/hr renewable feedstock is applied.

[0123] In the HydroFlex™ sweet mode, sour gases (H.sub.2S, and also NH.sub.3) are removed in the hydroprocessing stage 110 of the process, e.g. in a separator 116 therein. Renewable feedstock together with hydrogen is processed in a HDO unit followed by removal of H.sub.2S, NH.sub.3 and then processed in dewaxing unit (HDW unit) for subsequent production of e.g. renewable diesel.

[0124] Rapeseed oil is used as renewable feedstock. The feed rate to the hydroprocessing reactor is 100 kg/hr. Make-up hydrogen gas rate from hydrogen producing unit is 4.79 kg/hr (SOR), 4.84 kg/hr (EOR). Exit gas (purge gas) rate from the separation stage, i.e. first light hydrocarbon stream, is 2.5 kg/hr (SOR), 2.9 kg/hr (EOR), and off gas rate, i.e. second light hydrocarbon stream, is 5.0 kg/hr (SOR), 5.8 kg/hr (EOR). NG requirement is then 8.37 kg/hr (SOR), 7.34 kg/hr (EOR).

[0125] The percentage reduction in NG-consumption compared with non-integrated unit, providing same hydrogen requirement for hydrotreater is 45% (SOR), 52% (EOR). This represents also a reduction of steam reformer (HTCR) size by about 11% compared to case with 100% NG.

Example 3

[0126] As in Example 2, HydroFlex™ sweet mode unit was used, yet now for renewable jet fuel production. A HTCR unit for hydrogen production together with a PSA-unit for hydrogen purification was used, as well as prereforming and water gas shift.

[0127] Used cooking oil is used as renewable feedstock. The feed rate to the hydroprocessing reactor is 100 kg/hr. Make-up hydrogen gas rate from hydrogen producing unit 4.79 kg/hr (SOR) and 4.84 kg/hr (EOR). Exit gas (purge gas) rate is 0.0 kg/hr (SOR), 1.37 kg/hr (EOR) and off-gas rate is 11.58 kg/hr (SOR), 12.72 kg/hr (EOR). NG requirement is then 2.6 kg/hr (SOR), 0.20 kg/hr (EOR).

[0128] The percentage reduction in NG-consumption compared with non-integrated unit, providing same hydrogen requirement for hydrotreater is 84% (SOR), 98% (EOR), with about 10% saving in HTCR size compared to case with 100% NG.

[0129] These examples thus show a significant reduction in NG consumption in the range 40-90% or more, whilst at the same time enabling a smaller size of the hydrogen production unit.

[0130] Thereby also, CO.sub.2 emissions are drastically reduced. For instance, when having a NG consumption savings of about 70%, the CO.sub.2 emission (Nm.sup.3/1000 Nm.sup.3 H.sub.2) is also reduced by about 70%, as so are the operating expenses (about 70% cost reduction). Furthermore, there is a reduction in capital expenses of about 10%.

Example 4

[0131] This example shows some of the advantages of having the removal of H.sub.2S by amine scrubbing in the off-gas stream only. The basis for calculation is 100 kg/hr feed rate, as in previous examples. The percentage saving in steam is the same as the percentage saving in lean amine rates as these are proportional. The below table shows the results.

TABLE-US-00001 Amine consumption, kg/hr Steam savings in High Pressure absorber Off gas cleaning amine regeneration for total recycle gas to used by using Savings hydroprocessing HydroFlex ™ amine for off gas of lean Example (as used in prior art) (invention) cleaning only amine HydroFlex ™ sour 92.4 26.9 71% 71% mode unit HydroFlex ™ sweet 86.5 27.7 68% 68% mode unit HydroFlex ™ sweet 209.9 31.5 85% 85% mode jet production unit

[0132] The invention is further described by the following points (embodiments):

[0133] 1. A process for producing a hydrocarbon product, said process comprising the steps of:

[0134] i) passing a feedstock originating from a renewable source through a hydroprocessing stage for producing a main hydrotrotreated stream;

[0135] ii) passing the main hydrotreated stream to a separation stage for producing: [0136] an aqueous stream, [0137] a hydrogen-rich stream as a first recycle gas stream, [0138] an off-gas stream comprising hydrocarbons, [0139] and said hydrocarbon product, boiling at above 50° C.;

[0140] iii) passing the first recycle gas stream to the hydroprocessing stage;

[0141] iv) passing the off-gas stream as a second recycle gas stream to a hydrogen producing unit for producing a hydrogen stream as a make-up hydrogen stream;

[0142] v) passing the make-up hydrogen stream to the hydroprocessing stage;

[0143] wherein prior to conducting step iv), said off-gas stream passes to a separation stage, the separation stage preferably being at least one of an amine absorption stage, a caustic scrubber, and a sulfur absorbent, for removing H.sub.2S and thereby producing said second recycle gas stream.

[0144] 2. Process according to point 1, wherein the entire off-gas stream passes to the separation stage.

[0145] 3. Process according to any of points 1-2, wherein the entire second recycle gas stream passes to the hydrogen producing unit.

[0146] 4. Process according to any of points 1-3, wherein the process further comprises: vi) splitting said hydrogen-rich stream into said first recycle gas stream and a third recycle gas stream, and passing said third recycle gas stream to said hydrogen producing unit.

[0147] 5. Process according to any of points 1-4, wherein in step i) the hydroprocessing stage comprises:

[0148] i-1) passing the feedstock through a first catalytic hydrotreating unit under the addition of hydrogen for producing a first hydrotreated stream;

[0149] i-2) passing the first hydrotreated stream to a dewaxing section comprising a second catalytic hydrotreating unit under the addition of hydrogen for producing said main hydrotreated stream.

[0150] 6. Process according to point 5, wherein between step i-1) and i-2) the process further comprises passing the first hydrotreated stream to a separator, such as a high-pressure or low-pressure separator, for removing H.sub.2S, NH.sub.3, and H.sub.2O, thereby producing said first hydrotreated stream, and optionally also producing a vapor stream, and a recycle oil stream.

[0151] 7. Process according to any of points 1-6, wherein in step ii) the separation stage comprises:

[0152] ii-1) passing the main hydrotreated stream to a separator, preferably a cold separator, for producing said aqueous stream, said hydrogen-rich stream, and a heavy hydrocarbon stream;

[0153] ii-2) passing the heavy hydrocarbon stream to a fractionation section for producing said off-gas stream, and said hydrocarbon product.

[0154] 8. Process according to any of points 1-7, wherein in step v) the make-up hydrogen stream passes to at least one of: [0155] said first catalytic hydrotreating unit; [0156] said separator between step i-1) and i-2), such as a high pressure stripper; second catalytic hydrotreating unit; [0157] and optionally also an additional catalytic hydrotreating unit such as a third catalytic hydrotreating unit.

[0158] 9. Process according to any of points 1-8, wherein the first recycle gas stream is passed to the first catalytic hydrotreating unit

[0159] 10. Process according to point 8, wherein the first recycle gas stream is not subjected to a separation stage for removing H.sub.2S and/or CO.sub.2, optionally also for removing NH.sub.3 and/or CO, prior to being passed to the first catalytic hydrotreating unit.

[0160] 11. Process according to any of points 1-10, wherein the hydrogen producing unit comprises feeding: said second recycle gas stream, and a hydrocarbon feedstock such as natural gas, optionally together with one or more of said hydrocarbon products, preferably naphtha.

[0161] 12. Process according to any of points 1-11, wherein the hydrogen producing unit comprises subjecting the hydrocarbon feedstock to: cleaning in a cleaning unit, said cleaning unit preferably being a sulfur-chlorine-metal absorption or catalytic unit; optionally pre-reforming in a pre-reforming unit; catalytic steam methane reforming in a steam reforming unit; water gas shift conversion in a water gas shift unit; optionally carbon dioxide removal in a CO.sub.2-separator unit; and hydrogen purification in a hydrogen purification unit.

[0162] 13. Process according to point 12, wherein said second recycle gas stream is fed to the cleaning unit.

[0163] 14. Process according to any of points 1-13, wherein the hydrogen-rich stream, or first recycle stream, or third recycle stream comprises hydrogen in a concentration of 50 vol % or higher, and wherein any of said streams is passed through a hydrogen purification unit: prior to splitting said hydrogen-rich stream into a first recycle stream or a third recycle stream, or prior to passing the first recycle stream to the hydroprocessing stage, or prior to passing said third recycle stream to hydrogen producing unit.

[0164] 15. Process according to point 13, wherein the hydrogen purification unit is the hydrogen purification unit of the hydrogen producing unit, and said third recycle stream is passed through this hydrogen purification unit.

[0165] 16. Process according to point 15, wherein the hydrogen purification unit is a Pressure Swing Adsorption unit (PSA unit), said PSA unit producing an off-gas stream which is used as fuel in the steam reforming unit of the hydrogen producing unit, and/or in fired heaters in any of the catalytic hydrotreating units of the hydroprocessing stage, separation units of the separation stage, and/or for steam production.

[0166] 17. Process according to any of points 12-16, wherein the steam reforming unit is: a convection reformer, a tubular reformer, autothermal reformer (ATR), electrically heated steam methane reformer (e-SMR), or combinations thereof.

[0167] 18. Process according to any of points 1-17, wherein prior to passing the make-up hydrogen stream to the hydroprocessing stage, the make-up hydrogen stream passes through a compressor section comprising a make-up compressor optionally also a recycle compressor, the make-up compressor also producing a hydrogen recycle stream which is added to the hydrogen producing unit, preferably directly to the second recycle stream entering the hydrogen producing unit, and/or to the cleaning unit of the hydrogen producing unit.

[0168] 19. Process according to point 18, wherein prior to passing the first recycle stream to the hydroprocessing stage, the first recycle stream passes through said recycle compressor.

[0169] 20. Process according to any of points 1-19, wherein the feedstock is obtained from a raw material of renewable origin, such as originating from plants, algae, animals, fish, vegetable oil refining, domestic waste, waste rich in plastic, industrial organic waste like tall oil or black liquor, or a feedstock derived from one or more oxygenates taken from the group consisting of triglycerides, fatty acids, resin acids, ketones, aldehydes or alcohols where said oxygenates originate from one or more of a biological source, a gasification process, a pyrolysis process, Fischer-Tropsch synthesis, or methanol based synthesis.

[0170] 21. Process according to any of points 1-20, wherein step i) also comprises adding a feedstock originating from a fossil fuel source, such as diesel, kerosene, naphtha, and vacuum gas oil (VGO), and/or recycling a hydrocarbon product.

[0171] 22. Process according to any of points 1-21, wherein the first catalytic hydrotreating is hydrodeoxygenation (HDO), the second catalytic hydrotreating is hydrodewaxing (HDW), and an additional catalytic hydrotreating such as a third catalytic hydrotreating is hydrocracking (HCR).

[0172] 23. Process for producing a hydrocarbon product, said process comprising the steps of:

[0173] i) passing a feedstock originating from a fossil fuel source through a hydroprocessing stage for producing a main hydrotrotreated stream;

[0174] ii) passing the main hydrotreated stream to a separation stage for producing: [0175] optionally an aqueous stream, [0176] a hydrogen-rich stream as a first recycle gas stream, [0177] an off-gas stream comprising hydrocarbons, [0178] and said hydrocarbon product, boiling at above 50° C.;

[0179] iii) passing the first recycle gas stream to the hydroprocessing stage;

[0180] iv) passing the off-gas stream as a second recycle gas stream to a hydrogen producing unit for producing a hydrogen stream as a make-up hydrogen stream;

[0181] v) passing the make-up hydrogen stream to the hydroprocessing stage;

[0182] wherein prior to conducting step iv), said off-gas stream passes to a separation stage, the separation stage preferably being at least one of an amine absorption stage, a caustic scrubber, and a sulfur absorbent, for removing H.sub.2S and thereby producing said second recycle gas stream.

[0183] 24. Plant for producing a hydrocarbon product, comprising: [0184] a hydroprocessing section arranged to receive a feedstock originating from a renewable source and a compressed hydrogen-rich feed stream for producing a main hydrotreated stream; [0185] a separation section arranged to receive said main hydrotreated stream for producing an aqueous stream, a hydrogen-rich stream as a first recycle gas stream, an off-gas stream comprising hydrocarbons as a second recycle stream, and said hydrocarbon product, boiling at above 50° C.; [0186] a separation section, which is preferably at least one of an amine absorption stage, a caustic scrubber, and a sulfur absorbent, arranged to receive said off-gas stream, for removing H.sub.2S and thereby producing said second recycle gas stream; [0187] a hydrogen producing unit (HPU) arranged to receive said second recycle gas stream and a hydrocarbon feedstock for producing a make-up hydrogen stream; [0188] a compressor section arranged to receive said first recycle gas stream and at least a portion of the make-up hydrogen stream produced in said HPU, for generating said compressed hydrogen-rich feed stream and a make-up hydrogen recycle stream; [0189] a conduit for passing said first recycle gas stream to said compressor section; [0190] a conduit for passing said make-up hydrogen stream from the HPU to said compressor section; [0191] optionally a conduit for recycling said make-up hydrogen recycle stream to the HPU. [0192] optionally means for splitting said hydrogen-rich stream into said first recycle gas stream and a third recycle gas stream, and a conduit for passing said third recycle gas stream to said HPU.