WO2022034181A1

WO2022034181A1 - Process and plant for producing gasoline from a tar-containing feed

Info

Publication number: WO2022034181A1
Application number: PCT/EP2021/072523
Authority: WO
Inventors: Erik BEK-PEDERSEN; Søren Selde ENEVOLDSEN
Original assignee: Haldor Topsoe AS
Current assignee: Topsoe AS
Priority date: 2020-08-13
Filing date: 2021-08-12
Publication date: 2022-02-17
Anticipated expiration: 2023-02-13
Also published as: KR20230051170A; AU2021324383A1; CN116075478A; CN116075478B; EP4196557A1

Abstract

The present invention relates to a process and plant for producing hydrocarbon product boiling in the gasoline boiling range from a tar-containing feedstock, the process and 5plant comprising a hydroprocessing stage which includes hydrotreating and hydrocracking for producing diesel and naphtha, and subsequent aromatization of the naphtha thereby also producing a light hydrocarbon gas as liquid petroleum gas (LPG),from which a hydrogen stream is produced.

Description

Process and plant for producing gasoline from a tar-containing feed

FIELD OF THE INVENTION

The present invention relates to a process and plant for producing a high-quality gasoline from a tar-containing feedstock, the process and plant comprising one or more hydroprocessing stages which include hydrotreating and hydrocracking for producing diesel and naphtha, and subsequent aromatization of the naphtha, thereby also producing a light hydrocarbon gas as a liquid petroleum gas (LPG),from which a hydrogen stream is produced and which may be used in the process.

BACKGROUND

The quality of gasoline (C5+ hydrocarbons) is highly dependent on the resistance to engine knocking due to compression ignition of the fuel in engines running on the gasoline. This quality is measured by the so-called octane number, originating from isooctane being considered the ideal gasoline hydrocarbon. Thus, a pure iso-octane defines the gasoline as having the octane number 100, while a pure n-heptane defines the octane number 0. It would be desirable to produce a gasoline having a research octane number (RON) of at least 85, such as 90 or higher.

In practice, gasoline is a complex hydrocarbon mixture and e.g. aromatics contribute to higher knock-resistance, while saturated alkanes, especially when having a linear structure, have a higher propensity to knocking. Therefore, naphtha hydrocarbon mixtures are less valuable if the aromatic content is very low.

Naphtha having insufficient octane number may be upgraded by catalytic reforming process, which typically involves alkylation of aromatics to increase the octane number.

Applicant’s US 9,752,080 discloses the use of LPG from a downstream Fischer- Tropsch (FT) process as feed to a steam reforming process for producing synthesis gas required in the FT-process. WO 2015/075315 A1 discloses the use of LPG or naphtha in a hydrogen producing plant which is integrated in a process for producing hydrocarbons from a renewable feedstock.

US 3,871,993 describes a process for converting virgin naphtha to a high-octane liquid gasoline product and LPG without hydrogen consumption by increasing the aromatics content of the naphtha via the use of zeolite such as ZSM-5 which may be modified with metals.

WO 2016/054316 A1 discloses a process or plant for producing aromatic compounds, particularly a product rich in BTX (benzene, toluene, xylene) from gas condensates (wide boiling range condensates) having a low content of aromatics e.g. up to 40 wt% or up to 15 wt% (Table 1). The process includes the use of a hydroprocessing reactor, an aromatization reactor and a hydrogen extraction unit such as pressure swing adsorption unit (PSA unit). From the PSA unit, a LPG stream is withdrawn.

Applicant’s co-pending European patent application EP 20162995.3 describes the production of renewable hydrocarbon products such as renewable naphtha in a process including production of hydrogen in a hydrogen producing unit which may use such renewable naphtha as part of the hydrocarbon feedstock.

The prior art is silent about a process or plant for converting a feedstock originating from a tar-containing feedstock into a hydrocarbon product boiling in the gasoline boiling range by hydrotreating and hydrocracking, and at the same time producing a light hydrocarbon gas as LPG for use in the production of hydrogen which may be used in the process or plant.

SUMMARY OF THE INVENTION

In a first aspect of the invention there is provided a process for producing a hydrocarbon product boiling in the gasoline boiling range, said process comprising the steps of: i) converting a tar-containing feedstock such as coke oven tar (COT) by one or more hydroprocessing stages into a hydrocarbon product boiling at above 30°C, including a naphtha stream; wherein said one or more hydroprocessing stages comprise a hydrotreating and hydrocracking step, followed by a separation stage for thereby producing said naphtha stream; ii) upgrading said naphtha stream by passing said naphtha stream through an aromatization stage comprising contacting the naphtha stream with a catalyst, preferably a catalyst comprising an aluminosilicate zeolite, thereby producing said hydrocarbon product boiling in the gasoline boiling range and a separate light hydrocarbon gas stream as a liquid petroleum gas (LPG) stream; iii) passing at least a portion of said LPG stream to a hydrogen producing unit for producing a hydrogen stream;

In an embodiment according to the first aspect of the invention, the hydrocarbon product boiling at above 30°C comprises said naphtha, diesel and lube base stock (base oil for lubes).

It would be understood that the terms “stage” and “step” may be used interchangeably.

As used herein, the term “hydrocarbon product boiling in the gasoline boiling range” means boiling in the range 30-210°C.

As used herein “naphtha” means a hydrocarbon product boiling in the range 30-160°C.

As used herein, “diesel” means a hydrocarbon product boiling in the range 120-360°C, for instance 160-360°C.

As used herein, “lube base stock” means a hydrocarbon product boiling at above 390°C.

As used herein, boiling in a given range, shall be understood as a hydrocarbon mixture of which at least 80 wt% boils in the stated range.

As used herein, “light hydrocarbon gas” means a gas mixture comprising C1-C4 gases, in particular methane, ethane, propane, butane; the light hydrocarbon gas may also comprise i-C3, i-C4 and unsaturated C3-C4 olefins. A particular light hydrocarbon gas is LPG as defined below.

As used herein, “LPG” means liquid/liquified petroleum gas, which is a gas mixture mainly comprising propane and butane, i.e. C3-C4; LPG may also comprise i-C3, i-C4 and unsaturated C3-C4 such as C4-olefins.

It would be understood that in ii) the separate light hydrocarbon gas stream is a liquid petroleum gas (LPG) stream.

In an embodiment according to the first aspect of the invention, said hydrocarbon product boiling in the gasoline boiling range has at least 20 wt% aromatics in C5+, such as 20-50 wt% aromatics in C5+, and an octane number (Research Octane Number, RON) of at least 85, such as 90 or 95. As used herein, the term “high quality gasoline” is a hydrocarbon product in accordance with these specifications.

Preferably, RON is measured according to ASTM D-2699.

By the invention, step i) comprises a hydrotreating and hydrocracking step for thereby enabling deep sulfur and nitrogen removal, aromatic saturation and optional hydrocarbon product property improvement, followed by a separation stage for thereby producing said naphtha stream. In this separation stage or section, an LPG stream may also be produced, as well as other hydrocarbon products such as diesel.

Compared to other feedstocks, a tar-containing feedstock is particularly high in aromatics. For instance, coke oven tar may have at least 25 wt% aromatics, such as up to 50 wt% or 60 wt% aromatics. The present invention, counter-intuitively, purposely subjects this feedstock to hydrotreatment and hydrocracking steps which inevitably reduce the content of aromatic compounds, compounds which according to the invention are necessary for providing a higher RON and thereby high-quality gasoline. The process of the invention thus surprisingly reduces the amount of aromatics and later increases the amount of aromatics in order to obtain high quality gasoline along with a significant amount of light hydrocarbon gas, particularly LPG. The material catalytically active in hydrotreating (HDT), typically comprises an active metal (sulfided base metals such as nickel, cobalt, tungsten and/or molybdenum, but possibly also either elemental noble metals such as platinum and/or palladium) and a refractory support (such as alumina, silica or titania, or combinations thereof).

HDT conditions involve a temperature in the interval 250-400°C, a pressure in the interval 30-150 bar, and a liquid hourly space velocity (LHSV) in the interval 0.1-2, optionally together with intermediate cooling by quenching with cold hydrogen, feed or product

Optionally, a hydrodewaxing (HDW) stage may also be conducted. The material catalytically active in HDW typically comprises an active metal (either elemental noble metals such as platinum and/or palladium or sulfided base metals such as nickel, cobalt, tungsten and/or molybdenum), an acidic support (typically a molecular sieve showing high shape selectivity, and having a topology such as MOR, FER, MRE, MWW, AEL, TON and MTT) and a refractory support (such as alumina, silica or titania, or combinations thereof).

Isomerization conditions involve a temperature in the interval 250-400°C, a pressure in the interval 20-100 bar, and a liquid hourly space velocity (LHSV) in the interval 0.5-8.

The material catalytically active in hydrocracking (HCR) is of similar nature to the material catalytically active in isomerization, and it typically comprises an active metal (either elemental noble metals such as platinum and/or palladium or sulfided base metals such as nickel, cobalt, tungsten and/or molybdenum), an acidic support (typically a molecular sieve showing high cracking activity, and having a topology such as MFI, BEA and FAU) and a refractory support (such as alumina, silica or titania, or combinations thereof). The difference to material catalytically active isomerization is typically the nature of the acidic support, which may be of a different structure (even amorphous silica-alumina) or have a different acidity e.g. due to silica:alumina ratio.

HCR conditions involve a temperature in the interval 250-400°C, a pressure in the interval 30-150 bar, and a liquid hourly space velocity (LHSV) in the interval 0.5-8, optionally together with intermediate cooling by quenching with cold hydrogen, feed or product

Optionally, other types of hydrotreating are included, for instance hydrodearomatization (HDA). The material catalytically active in HDA typically comprises an active metal (typically elemental noble metals such as platinum and/or palladium but possibly also sulfided base metals such as nickel, cobalt, tungsten and/or molybdenum) and a refractory support (such as amorphous silica-alumina, alumina, silica or titania, or combinations thereof).

HDA conditions involve a temperature in the interval 200-350°C, a pressure in the interval 20-100 bar, and a liquid hourly space velocity (LHSV) in the interval 0.5-8.

Tar is a heavy hydrocarbonaceous liquid, which is often considered an undesirable byproduct from coal processing such as coal gasification, and there are significant costs and efforts associated with the disposal of surplus tar. Hence, the present invention generates a high-quality gasoline by processing and upgrading an otherwise not very desirable industrial by-product.

As used herein, “coal gasification” shall be understood as a process comprising coking processes, which destructively distill the coal feedstock, to produce coke with a high carbon content, a gas phase and a liquid phase, coal tar. Such coal tar is characterized by a high presence of heteroatoms (especially nitrogen, sulfur and oxygen) as well as a high content of aromatics.

Terms such as coal tar and coke oven tar may be used to indicate the source of the tar. For the purpose of the present application tar is typically a product of coal gasification. The terms “coal tar” and “coke oven tar” are used interchangeably throughout this application.

The term tar-containing feedstock may also include a product from the pyrolysis of tyres, e.g. waste tyres. In an embodiment according to the first aspect of the invention, the tar-containing feedstock is a product from the pyrolysis of tires and which contains at least 45 wt% aromatics, for instance 50 wt% or higher, e.g. 50-75 wt%, preferably as measured by ASTM D-6591 or ASMT D-6729.

Pyrolysis, as is well known in the art, means the thermal decomposition of a material, e.g. waste tyres, by exposure to high temperatures such as from 300°C up to 700°C, 800°C or-900°C in an inert atmosphere such as nitrogen.

In an embodiment according to the first aspect of the invention, the tar-containing feedstock is a coke oven tar containing at least 25 wt% aromatics, such as at least 30%, or at least 40 wt%, for instance 50 wt% or 60 wt%, preferably as measured by ASTM D-6591 or ASMT D-6729. Thus, a significant amount of aromatics is present in the tar-containing feedstock.

By treating a tar containing feedstock such as coke over tar, the naphtha stream obtained as intermediate product is highly naphthenic. For instance, this naphtha stream contains, preferably as measured by ASTM D-6729: at least 50 wt% naphthenes, such as at least 60 wt%, or at least 70 wt%, for instance 75 wt% or 80 wt; preferably less than 15 wt% n+i paraffins, for instance less than 12 wt% i-paraffins and less than 3 wt% n-paraffins; preferably less than 1 wt% olefins, for instance less than 0.5 wt% olefins; and for instance also below 10 wt% aromatics, such as 6 wt% or 4-5 wt%. Thus, there is a significant reduction in the content of aromatics.

The subsequent aromatization stage of the naphtha stream, instead of e.g. simply using it directly as source of hydrogen in a hydrogen producing unit and rather focusing on diesel as the main product, results in a large amount of aromatics thereby increasing the octane number (RON) to at least 85, particularly 90 or higher, from as low as 50-60 in the naphtha stream, while at the same time, a significant amount of light hydrocarbon gas, particularly LPG, is also produced e.g. 30-50 wt% LPG. The gasoline yield (C5+ yield) can also be obtained at desired levels e.g. 40-60 wt%.

The need for hydrogen in the process would typically be satisfied by using coke oven gas as hydrogen source or another external source. However, when using coke oven gas there is a deficit of hydrogen, so the utilization of the light hydrocarbon gas, particularly LPG, for producing hydrogen in step iii) enables closing the hydrogen balance and even generate surplus hydrogen. The naphtha stream, being highly naphthenic, is thus segregated into low hydrogen high-octane aromatic naphtha and LPG with increased hydrogen density i.e. H:C-ratio and which is used for hydrogen production. A high energy efficiency in the process and plant is thereby obtained whilst at the same time a high-quality gasoline product is obtained from the otherwise not very desirable industrial by-product (tar). Diesel produced in the process, and which normally is the desired hydrocarbon product, may also be used as part of the hydrocarbon product pool.

Hence, by the invention, a simple and elegant solution to the creation of valuable products on the basis of a tar-containing feedstock is achieved, by enabling among other things a significant improvement, i.e. more than expected increase of the octane number (RON) of the naphtha stream. Hence, it is possible to increase the aromatics content from less than e.g. 4-5 wt% in the naphtha to 20 wt% or more, such as 20-50 wt%, 25-45 wt%, or 35-45 wt% aromatics in C5+ in the high-quality gasoline. The octane number (RON) of the high-quality gasoline, having at least 20-45 wt% aromatics, is 85 or higher, such as 90 or 95. The higher the aromatics content of the gasoline, the lower the C5+ yield, yet by the invention it is possible to strike a balance by which the octane number increases significantly without reducing too much the C5+ yield. At the same time, a significant amount of LPG is formed as an additional valuable product due to the dehydrogenation that happens when aromatics are formed, and which is then converted to hydrogen in a steam reforming process in the hydrogen producing unit.

In addition, the invention enables a simpler approach than e.g. catalytic reforming of the naphtha, since the aromatization stage can be conducted at milder conditions, with less expensive catalyst and less expensive process equipment. More specifically, there is no need for noble metals or rare earth metals on the catalyst, there is no chlorine, the catalytic reactor can be operated as a fixed-bed reactor operation and thus represents a much simpler solution than conventional catalytic reformers. In an embodiment according to the first aspect of the invention, the process further comprises: 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).

Thus, the produced hydrogen stream may be used as make-up hydrogen to provide hydrogen during the production of the gasoline, thereby improving the energy efficiency of the overall process and plant. As used herein, the term “overall process and plant” means the process and plant used to convert the tar-containing feedstock to the hydrocarbon product boiling in the gasoline boiling range in accordance with above steps i)-iv). It would be understood that this encompasses also any of the below embodiments.

In an embodiment according to the first aspect of the invention, the tar-containing feedstock is passed through an acid wash step prior to passing to said step i). This removes impurities in the feedstock which may be detrimental for i.a. downstream catalysts.

In an embodiment according to the first aspect of the invention, step i) comprises a conditioning step including the use of one or more guards, e.g. bed guards, for the removal of metals, removal of di-olefins, and removal of bulk sulfur and nitrogen.

In an embodiment according to the first aspect of the invention, in step (ii) the catalyst is incorporated, e.g. supported, in an aluminosilicate zeolite, such as a catalyst incoroporated in a zeolite having a MFI structure, in particular ZSM-5, preferably Zn- ZSM-5, ZnP-ZSM-5, Ni-ZSM-5, or combinations thereof; the temperature is in the range 300-500°C, such as 300-460°C or 300-420°C, the pressure is 1-30 bar such as 2-30 bar or 10-30 bar, and optionally there is addition of hydrogen, i.e. optionally, the aromatization is conducted in the presence of hydrogen. In a particular embodiment, the liquid hourly space velocity (LHSV) is in the interval 1-3, for instance 1.5-2.

As used herein, the term “MFI structure” means a structure as assigned and maintained by the International Zeolite Association Structure Commission in the Atlas of Zeolite Framework Types, which is at http:// www.iza-structure.org/databases/ or for instance also as defined in “Atlas of Zeolite Framework Types”, by Ch. Baerlocher, L.B. McCusker and D.H. Olson, Sixth Revised Edition 2007.

As used herein, “Zn-ZSM-5” means Zn incorporated in the zeolite ZSM-5, and includes Zn supported on ZSM-5. The same interpretation applies when using ZnP, or Ni.

In an embodiment according to the first aspect of the invention, step ii) comprises providing after said aromatization stage an isomerization stage, said aromatization stage producing a raw upgraded naphtha stream which is passed through said isomerization stage for thereby forming said hydrocarbon product boiling in the gasoline boiling range. The above recited isomerization conditions may be used in this isomerization.

In a particular embodiment, the process further comprises using a portion of a light hydrocarbon gas stream, e.g. a LPG stream, in particular the light hydrocarbon gas stream obtained in step ii), or a portion of the naphtha stream as heat exchanging medium for quenching said raw upgraded naphtha stream.

Thereby a staged feeding of the feed to the isomerization stage is achieved to improve isomerization and thereby also an increase in aromatization. Isomerization is favored by a lower temperature than the aromatization. Further, make-up hydrogen, for instance hydrogen produced in the hydrogen producing unit may be added in the isomerization, i.e. hydroisomerization (HDI). The product of the aromatization stage gains thereby also an even higher octane number than it otherwise would be possible, i.e. without the isomerization.

In an embodiment according to the first aspect of the invention, the hydrogen producing unit comprises feeding a hydrocarbon feedstock such as natural gas. Hence, the hydrogen producing unit, apart from using the light hydrocarbon gas, LPG, as feedstock, may also use another hydrocarbon feedstock, such as natural gas.

Optionally, in step i) a separate LPG stream is also formed which is also used as hydrocarbon feedstock in the hydrogen producing unit. Preferably the naphtha stream and LPG stream in step i) are withdrawn from the same unit, such as a separation unit e.g. a distillation unit.

In an embodiment according to the first aspect of the invention, the hydrogen producing unit comprises subjecting said light hydrocarbon gas stream and said 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 CO2- separator unit; and optionally hydrogen purification in a hydrogen purification unit. It would be understood that the provision of said another i.e. separate hydrocarbon feedstock, such as natural gas, is optional.

In a particular embodiment, 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. This enables further reduction of hydrocarbon consumption, thereby improving energy consumption figures, i.e. higher energy efficiency, as PSA off-gas which otherwise will need to be burned off (flared), is expediently used in the process.

In an embodiment according to the first aspect of the invention, the steam reforming unit is: a convection reformer, preferably comprising one or more bayonet reforming tubes such as an HTCR reformer i.e. Topsoe bayonet reformer, where the heat for reforming is transferred by convection along with radiation; a tubular reformer i.e. conventional steam methane reformer (SMR), where the heat for reforming is transferred chiefly by radiation in a radiant furnace; autothermal reformer (ATR), where partial oxidation of the hydrocarbon feed with oxygen and steam followed by catalytic reforming; electrically heated steam methane reformer (e-SMR), where electrical resistance is used for generating the heat for catalytic reforming; or combinations thereof. In particular, when using e-SMR, electricity from green resources may be utilized, such as from electricity produced by wind power, hydropower, and solar sources, thereby further minimizing the carbon dioxide footprint. For more information on these reformers, details are herein provided by direct reference to Applicant’s patents and/or literature. For instance, for tubular and autothermal reforming an overview is presented in “Tubular reforming and autothermal reforming of natural gas - an overview of available processes”, lb Dybkjaer, Fuel Processing Technology 42 (1995) 85-107; and EP 0535505 for a description of HTCR. For a description of ATR and/or SMR for large scale hydrogen production, see e.g. the article “Large-scale Hydrogen Production”, Jens R. Rostrup-Nielsen and Thomas Rostrup-Nielsen”, CATTECH 6, 150-159 (2002).

For a description of e-SMR which is a more recent technology, reference is given to particularly WO 2019/228797 A1.

In an embodiment, the catalyst in the steam reforming unit is a reforming catalyst, e.g. a nickel-based catalyst. In an embodiment, the catalyst in the water gas shift reaction is any catalyst active for water gas shift reactions. The said two catalysts can be identical or different. Examples of reforming catalysts are Ni/MgAI2O4, Ni/AI2O3, Ni/CaAI2O4, Ru/MgAI2O4, Rh/MgAI2O4, lr/MgAI2O4, Mo2C, Wo2C, CeO2, Ni/ZrO2, Ni/MgAI2O3, Ni/CaAI2O3, Ru/MgAI2O3, or Rh/MgAI2O3, a noble metal on an AI2O3 carrier, but other catalysts suitable for reforming are also conceivable. The catalytically active material may be Ni, Ru, Rh, Ir, or a combination thereof, while the ceramic coating may be AI2O3, ZrO2, MgAI2O3, CaAI2O3, or a combination therefore and potentially mixed with oxides of Y, Ti, La, or Ce. The maximum temperature of the reactor may be between 850-1300°C. The pressure of the feed gas may be 15-180 bar, preferably about 25 bar. Steam reforming catalyst is also denoted steam methane reforming catalyst or methane reforming catalyst.

In an embodiment according to the first aspect of the invention, prior to passing the hydrogen stream to any of the hydroprocessing stages of step i) and/or the aromatization stage of step ii), 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, and/or to the cleaning unit of the hydrogen producing unit. This enables integration of the hydrogen producing plant and the plant for producing the hydrocarbon product boiling in the gasoline boiling range, since there is no need for a separate or dedicated compressor for recycling hydrogen within the hydrogen producing unit for e.g. hydrogenation of sulfur in the cleaning unit.

In a second aspect, the invention is a plant, i.e. process plant, for producing a hydrocarbon product boiling in the gasoline boiling range, comprising:

- a hydroprocessing section arranged to receive a tar-containing feedstock, and optionally also for receiving a compressed hydrogen stream for producing a naphtha product; said hydroprocessing section comprising a hydrotreating unit and a hydrocracking unit;

- an aromatization section comprising a reactor containing a catalyst, preferably a catalyst comprising an alumininosilicate zeolite, and arranged to receive said naphtha product for producing said hydrocarbon product boiling in the gasoline boiling range and a light hydrocarbon gas stream 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.

Any of the above embodiments of the first aspect of the invention and associated benefits may be used together with the second aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The sole figure shows a schematic flow diagram of the overall process/plant according to an embodiment of the invention.

DETAILED DESCRIPTION

With reference to the accompanying figure, a block flow diagram of the overall process/plant 10 is shown, where a tar-containing feedstock 12 such as a coke oven tar feed or a product from pyrolsysis of tyres e.g. waster tyres, is introduced to the hydroprocessing stage 110. This stage or section 110 comprises a feed section and reactor section 110’ including a conditioning step or section including the use of one or more guards, e.g. bed guards, for the removal of metals, removal of di-olefins, and removal of bulk sulfur and nitrogen. The stage or section 110 comprises also one or more hydrotreating (HDT) units (reactors) as well as one or more downstream hydrocracking (HCR) units, for thereby enabling deep sulfur and nitrogen removal and aromatic saturation. An optional hydrocarbon product property improvement may also be provided. Hydroprocessing stage or section 110 includes a separation stage 110” which produces hydrocarbon products in the form of naphtha stream 14 as an intermediate product, 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. The naphtha stream 14 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 in the resulting hydrocarbon product boiling in the gasoline boiling range 22, by forming a high-quality gasoline product having an octane number (RON) of 85 or higher, such as 90 or higher. The aromatization stage 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.

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 prereformer 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. Offgas 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. The hydrogen stream 28 may be exported as a product and/or may be used as makeup hydrogen in the process. Thus, for using 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 makeup 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.

Claims

1. A process for producing a hydrocarbon product boiling in the gasoline boiling range, said process comprising the steps of: i) converting a tar-containing feedstock by one or more hydroprocessing stages into a hydrocarbon product boiling at above 30°C, including a naphtha stream; wherein said one or more hydroprocessing stages comprise a hydrotreating and hydrocracking step, followed by a separation stage for thereby producing said naphtha stream; ii) upgrading said naphtha stream by passing said naphtha stream through an aromatization stage comprising contacting the naphtha stream with a catalyst, preferably a catalyst comprising an aluminosilicate zeolite, thereby producing said hydrocarbon product boiling in the gasoline boiling range and a separate light hydrocarbon gas stream as a 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.

2. Process according to claim 1 , wherein the tar-containing feedstock is a product from the pyrolysis of tires which contains at least 45 wt% aromatics, for instance 50 wt% or higher.

3. Process according to claim 1, wherein the tar-containing feedstock is a coke oven tar containing at least 25 wt% aromatics, such as at least 30%, or at least 40 wt%, for instance 50 wt% or 60 wt%.

4. Process according to any of claims 1-3 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).

5. Process according to any of claims 1-4, wherein the tar-containing feedstock is passed through an acid wash step prior to passing to said step i).

6. Process according to any of claims 1-5, wherein step i) comprises a conditioning step including the use of one or more guards, e.g. bed guards, for the removal of metals, removal of di-olefins, and removal of bulk sulfur and nitrogen.

7. A process according to any of claims 1-6, wherein in step (ii) the catalyst is incorporated in an aluminosilicate zeolite, such as a catalyst incorporated in a zeolite having a M Fl-structure, in particular ZSM-5, preferably Zn/ZSM-5, ZnP/ZSM-5, Ni/ZSM- 5, or combinations thereof; the temperature is in the range 300-500°C, the pressure is 1-30 bar, and optionally there is addition of hydrogen.

8. A process according to any of claims 1-7, wherein step ii) comprises providing after said aromatization stage an isomerization stage, said aromatization stage producing a raw upgraded naphtha stream which is passed through said isomerization stage for thereby forming said hydrocarbon product boiling in the gasoline boiling range.

9. A process according to claim 8, further comprising using a portion of a light hydrocarbon gas stream or a portion of the naphtha stream as heat exchanging medium for quenching said raw upgraded naphtha stream.

10. Process according to any of claims 1-9, wherein the hydrogen producing unit comprises feeding a hydrocarbon feedstock such as natural gas.

11. Process according to any of claims 1-10, wherein the hydrogen producing unit comprises subjecting said light hydrocarbon gas stream and said 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 CO2- separator unit; and optionally hydrogen purification in a hydrogen purification unit. 18

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 hydroprocessing stages of step i), and or the aromatization stage of step ii), and/or for steam production.

13. Process according to any of claims 1-12, 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.

14. Process according to any of claims 1-13, 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 optionally also a recycle 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.

15. A plant for producing a hydrocarbon product boiling in the gasoline boiling range, comprising:

- a hydroprocessing section arranged to receive a tar-containing feedstock, and optionally also for receiving a compressed hydrogen stream for producing a naphtha product, said hydroprocessing section comprising a hydrotreating unit and a hydrocracking unit;

- an aromatization section comprising a reactor containing a catalyst, preferably a catalyst comprising an alumininosilicate zeolite, and arranged to receive said naphtha product for producing said hydrocarbon product boiling in the gasoline boiling range and a light hydrocarbon gas as a liquid petroleum gas (LPG) stream;