PROCESS AND PLANT FOR PRODUCING GASOLINE FROM A RENEWABLE FEED

Abstract

The present invention relates to a process and plant for producing hydrocarbon product boiling in the gasoline boiling range from a feedstock originating from a renewable source, the process and plant comprising a hydroprocessing stage which includes hydrodoxygenation for producing renewable diesel and renewable naphtha, and subsequent aromatization of the renewable naphtha thereby also producing a lighthydrocarbon gas stream, such as liquid petroleum gas (LPG), from which a hydrogen stream is produced.

Claims

1. A process for producing a hydrocarbon product boiling in the gasoline boiling range, said process comprising the steps of: i) converting a feedstock originating from a renewable source by one or more hydroprocessing stages into a hydrocarbon product boiling at above 30° C., including a renewable naphtha stream; wherein the one or more hydroprocessing stages comprises: hydrodeoxygenation (HDO); ii) upgrading upgrading said renewable naphtha stream by passing it through an aromatization stage comprising contacting the renewable naphtha stream with a catalyst, thereby producing said hydrocarbon product boiling in the gasoline boiling range and a separate light hydrocarbon gas stream, such as liquid petroleum gas (LPG) stream; iii) passing at least a portion of said light hydrocarbon gas stream to a hydrogen producing unit for producing a hydrogen stream; and wherein said hydrocarbon product boiling in the gasoline boiling range has at least 20 wt % aromatics in C5+ and an octane number (RON) of at least 85.

2. Process according to claim 1 further comprising: iv) passing at least a portion of the hydrogen stream to any of the hydroprocessing stages of step i) and/or the aromatization stage of step ii).

3. A process according to claim 1, wherein in step (ii) the catalyst is incorporated in an aluminosilicate zeolite, the temperature is in the range 300-500° C., and the pressure is 1-30 bar.

4. A process according to claim 1, wherein step ii) comprises providing after said aromatization stage an isomerization stage, said aromatization stage producing a raw upgraded renewable naphtha stream which is passed through said isomerization stage for thereby forming said hydrocarbon product boiling in the gasoline boiling range.

5. A process according to claim 4, further comprising using a portion of a light hydrocarbon gas stream or a portion of the renewable naphtha stream as heat exchanging medium for quenching said raw upgraded renewable naphtha stream.

6. Process according to claim 1, wherein the hydrogen producing unit comprises feeding a hydrocarbon feedstock such as natural gas.

7. Process according to claim 1, wherein the hydrogen producing unit comprises subjecting said light hydrocarbon gas stream and said hydrocarbon feedstock to: cleaning in a cleaning unit.

8. Process according to claim 7, 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 hydroprocessing stages of step i), and or the aromatization stage of step ii), and/or for steam production.

9. Process according to claim 1, 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.

10. Process according to claim 1, wherein prior to passing the hydrogen stream to any of the hydroprocessing stages of step i) and/or the aromatization stage of step ii), the 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, and/or to the cleaning unit of the hydrogen producing unit.

11. Process according to claim 1, wherein in step i) the renewable source is a raw material of renewable origin, such as originating from plants, algae, animals, fish, vegetable oil refining, domestic waste, tires, 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, hydrothermal liquefaction or any other liquefaction process, Fischer-Tropsch synthesis, or methanol based synthesis.

12. 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.

13. A plant for producing a hydrocarbon product boiling in the gasoline boiling range, comprising: a hydroprocessing section arranged to receive a feedstock originating from a renewable source and optionally also for receiving a compressed hydrogen stream, for producing a renewable naphtha product; said hydroprocessing section comprising a hydrodeoxygenation (HDO) unit, optionally a hydrodewaxing (HDVV) unit and optionally a hydrocracking (HCR) unit; an aromatization section comprising a reactor containing a catalyst, preferably a catalyst comprising an alumininosilicate zeolite, and arranged to receive said renewable naphtha product for producing said hydrocarbon product boiling in the gasoline boiling range and a light hydrocarbon gas stream, such as a liquid petroleum gas (LPG) stream; a hydrogen producing unit (HPU) arranged to receive said light hydrocarbon gas stream and optionally arranged to also receive a separate hydrocarbon feedstock stream such as natural gas stream for producing a hydrogen stream.

14. The process of claim 1, wherein the one or more hydroprocessing stages comprises: hydrodewaxing (HDVV) and/or hydrocracking (HCR).

15. The process of claim 1, wherein the catalyst comprises an aluminosilicate zeolite.

16. The process of claim 3, wherein step (ii) comprises addition of hydrogen.

17. The process of claim 3, wherein aluminosilicate zeolite is a zeolite having an MFI-structure selected from the group consisting of Zn-ZSM-5, ZnP-ZSM-5, Ni-ZSM-5, and combinations thereof.

18. The process of claim 7, wherein said cleaning unit is a sulfur-chlorine-metal absorption or catalytic unit.

19. The process of claim 7, wherein the hydrogen producing unit comprises subjecting said light hydrocarbon gas stream and said hydrocarbon feedstock to: pre-reforming in a pre-reforming unit; catalytic steam methane reforming in a steam reforming unit; and/or water gas shift conversion in a water gas shift unit; and/or carbon dioxide removal in a CO2-separator unit; and/or hydrogen purification in a hydrogen purification unit.

20. The process of claim 10, wherein the hydrogen stream passes through the compressor section further comprising a recycle compressor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] The sole FIGURE shows a schematic flow diagram of the overall process/plant according to an embodiment of the invention.

DETAILED DESCRIPTION

[0071] With reference to the FIGURE, a block flow diagram of the overall process/plant 10 is shown, where a feedstock from a renewable source 12 is fed to the hydroprocessing stage 110. This stage or section comprises a feed section and reactor section 110′ including HDO, optional HDW and HCR units, and a separation stage 110″ which produces hydrocarbon products in the form of renewable naphtha 14 as an intermediate product, renewable diesel 16 and a bottom product such as lube base stock (base oil for lubes) 18. In addition, an LPG stream 20 is also produced. In view of diesel normally matching in boiling point with the intermediate product from HDO, the normal choice would be to focus on producing the renewable diesel 16. However, by the present invention, the focus is the production of gasoline, in spite of yield loss, from the renewable naphtha instead.

[0072] The renewable naphtha 14, instead of being used as hydrocarbon source for hydrogen production, is then passed to aromatization stage 120 comprising a reactor containing a catalyst comprising an aluminosilicate zeolite, thereby increasing the aromatic content of the naphtha and significantly increasing the octane number, by forming a high-quality gasoline product 22 having an octane number (RON) of 85 or higher, such as 90 or higher. The aromatization stage 120 may also include an isomerization stage (not shown). From this aromatization stage 120 a light hydrocarbon gas stream, in particular LPG stream 24, is produced, which is then used as feed for the hydrogen producing unit 130, together with an optional separate hydrocarbon feedstock stream 26 such as natural gas used as make-up gas for the steam reforming in the hydrogen producing unit 130. LPG stream 20 from the separation section 110″ may also be added, as shown in the FIGURE. The LPG stream(s) may be mixed and then co-fed with the natural gas stream 26 to the hydrogen producing unit 130.

[0073] The hydrogen producing unit 130 comprises a first section 130′ 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 (e.g. 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 130″, is optionally provided to further enrich the gas and produce a hydrogen stream 28. Off-gas 30 from the PSA unit (PSA off-gas) 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.

[0074] The hydrogen stream 28 may be exported as hydrogen product of renewable origin and/or may be used as make-up hydrogen in the process. Thus, when used in the process, the hydrogen stream 28 passes to a compressor section 140 which includes make-up gas compressor an optionally also a recycle compressor, not shown. An optional hydrogen-rich stream (not shown) which may have been produced in the hydroprocessing stage 110 and make-up hydrogen stream 28 are then compressed by respectively the recycle compressor and the make-up compressor and used for adding hydrogen as make-up hydrogen stream 30 into the hydroprocessing stage 110, and optionally also (not shown) to the aromatization stage 120. From the make-up compressor, a hydrogen stream 32 is recycled to hydrogen production unit 130.