Process and plant for conversion of alcohols to hydrocarbons

Abstract

Process and plant for producing hydrocarbons, comprising: supplying an alcohol feed stream to an alcohol-to-hydrocarbons (ATH) synthesis section, said ATH synthesis section comprising an alcohol-to-olefins (ATO) section, said ATO section comprising an alcohol-to-olefin reactor (ATO) reactor; said alcohol feed stream being any of: i) a combination of a C2-C8 alcohol stream and a methanol (MeOH) stream; ii) a C2-C8 alcohol stream and a MeOH stream being supplied separately; iii) a combination thereof; supplying said alcohol feed stream to the ATO reactor, the ATO reactor comprising an adiabatic fixed bed reaction zone having a conversion catalyst comprising a zeolite with a framework having a ring pore structure, said ring pore structure being a unidi-mensional (1D) pore structure; and providing a first product rich in olefins as said hydrocarbons; wherein the weight ratio of the C2-C8 alcohol to methanol (MeOH) in any of said alcohol feed streams is in the range 0.30-6.0.

Description

[0001] Title: Process and plant for conversion of alcohols to hydrocarbons

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to the conversion of oxygenates to hydrocarbons, such as the conversion of methanol or ethanol into hydrocarbons such as a jet fuel, suitably as sustainable aviation fuel (SAF).

[0004] FIELD OF THE INVENTION

[0005] The production of hydrocarbons in the transportation fuel range such as jet fuel is currently made from fossil sources. Recent concepts to produce jet fuel include converting methanol to olefins in a methanol-to-olefins (MTO) step, optionally followed by further oligomerization in an oligomerization step and a conditioning step including hydrogenation to convert olefins to paraffins and finally a fractionation step. For instance, applicant’s WO2022063992 discloses a process for producing hydrocarbons boiling in the jet fuel boiling range, particularly as sustainable aviation fuel (SAF), as well as high grade propylene as a chemical product. It is also known that ethanol can be converted to jet fuel in a similar way, yet this is not in current industrial use.

[0006] Related prior art is also disclosed in WO 2009063177 A1 .

[0007] SUMMARY OF THE INVENTION

[0008] It would be desirable to be able to convert methanol (MeOH) and higher alcohols such as ethanol (EtOH) in connection with methanol-to-hydrocarbon (MTH) reactions or more generally alcohol-to-hydrocarbon (ATH) reactions, for instance alcohol-to-olefin (ATO) reactions, into synthetic fuels such as jet fuel and chemicals such as propylene (C3= or interchangeably propene). However, using EtOH as feed for an ATO reaction poses significant problems, as outlined below.

[0009] Using pure EtOH as feed instead of pure MeOH for the MTH reactions has at least two inherent problems arising from the fact that EtOH loses water and forms ethylene very fast in the ATO reactor: 1) ethylene is the least reactive of all the olefins in the ATO reaction; 2) EtOH (C2-alcohol) dehydration to ethylene is an endothermic reaction by approximately 47 kJ / mol ethylene, and by approximately 35 and 33 kJ / mol for, respectively, propanol (C3-alcohol) and butanol (C4-alcohol) dehydration, as well as approximately 32 kJ / mol for C8-alcohol dehydration to 1 -octene, which in an industrial reactor causes a sudden and steep drop in the inlet temperature of the ATO reactor. If not compensated for by increasing the inlet temperature to the ATO reactor, it can cause the ATO reaction to extinguish. On the other hand, when the inlet temperature to the ATO reactor is raised, it moves the ATO product distribution towards lighter hydrocarbons, which will decrease the overall hydrocarbon product value, as there is less production of the desired heavier hydrocarbons, such as hydrocarbons in the jet fuel range.

[0010] It would therefore be desirable to be able to overcome the above problems.

[0011] More generally, it would be desirable to provide a simple and efficient process and plant for converting methanol and higher alcohols such as EtOH to hydrocarbons, such as hydrocarbons boiling in the jet fuel range.

[0012] Accordingly, in a first aspect, the invention is a process for producing hydrocarbons, comprising:

[0013] - supplying an alcohol feed stream to an alcohol-to-hydrocarbons (ATH) synthesis section, said ATH synthesis section comprising an alcohol-to-olefins (ATO) section, said ATO section comprising an alcohol-to-olefin reactor (ATO) reactor; said alcohol feed stream being any of: i) a combination of a C2-C8 alcohol stream and a methanol (MeOH) stream; ii) a C2-C8 alcohol stream and a MeOH stream being supplied separately; iii) a combination thereof, i.e. a combination of i and ii;

[0014] - supplying said alcohol feed stream to the ATO reactor, the ATO reactor comprising an adiabatic fixed bed reaction zone having a conversion catalyst comprising a zeolite with a framework having a 10-ring pore structure, said 10-ring pore structure being a unidimensional (1 D) pore structure; and providing a first product rich in olefins as said hydrocarbons; wherein the weight ratio of the C2-C8 alcohol to methanol (MeOH) in any of said alcohol feed streams is in the range 0.30-6.0. In an embodiment, said C2-C8 alcohol is a C2-C4 alcohol.

[0015] Hence, the present invention shows how to combine methanol and higher alcohols (C2-C8 alcohols), such as ethanol, as feed to produce hydrocarbons such as jet fuel. It is shown that there is an unexpected beneficial effect of limiting the EtOH / MeOH ratio to a certain range. Furthermore, and in connection thereto, the inherent problem of temperature drop associated with ethanol dehydration to ethylene is solved by, in an embodiment, introducing ethanol to the ATO reactor downstream the introduction of the methanol feed in such way as to minimize the inlet temperature and / or reduce the recy- cle-to-makeup ratio and to improve the yield of higher (C5+) olefins, and advantageously also the yield of C4-olefins (C4=). Also in connection thereto, the production of paraffins, isoparaffins and naphthenes (P / l / N) is at the same time tuned with respect to the C5+ olefin production and C4-olefin production, so that the P / l / N yield (in vol.%; see appended Fig. 1) is maintained at 10% or below, while the C5+ olefin yield is more than 25% and the C4-olefin yield is 20% or higher. The C4-olefins are easy to convert to jet fuel range hydrocarbons, C8-C19 olefins such as C8-C16 olefins by subsequent oligomerization (OLI). The simultaneous reduction of P / l / N yield to below 10% is highly beneficial for the following reasons: a) the paraffins and to an extent the l / N fraction are not reactive and therefore not advantageous to the further processing of the product from the ATO reactor; b) the balance obtained between these components and the especially difficult to react ethylene is what is giving the increased average olefin chain length; c) the formation of these P / l / N products is associated with coke formation on the catalyst, decreasing the time between catalyst regenerations and therefore decreasing catalyst lifetime as the regeneration of the catalyst further deactivates it, so a cumulative technical effect of lesser coke formation on the zeolite is achieved.

[0016] In an embodiment, said first product rich in olefins comprises: at least 20 vol% C4-ole- fins; and at least 25 vol% C5+ hydrocarbons of which at least 20 vol% are C5-C8 olefins. Thereby, olefins are produced, e.g. C5-C8 or C5-C9 olefins, which are suitable for further conversion in an OLI reactor to jet fuel range hydrocarbons (olefins) such as C8-C19, e.g. C8-C16. The olefins may be hydroprocessed, e.g. hydrogenated to the jet fuel range hydrocarbons C8-19, e.g. C8-C16 hydrocarbons. In an embodiment, the C2-C4 alcohol is ethanol (EtOH) and the weight ratio of EtOH to MeOH is 0.36-5.75, such as 0.43-4.55.

[0017] As recited above, unexpected synergies have been identified by combining methanol and for instance ethanol in a certain ratio, expressed as the weight ratio (kg EtOH / kg MeOH) being in the range 0.30-6.0, for instance 0.36-5.75, the latter corresponding to a EtOH mole fraction x(EtOH) of 0.20-0.80; or for instance 0.43-4.55 corresponding to a EtOH mole fraction x(EtOH) of 0.23-0.76.

[0018] It would be understood that the weight ratio of EtOH to MeOH is calculated as x(EtOH) / (1-x(EtOH) • 1.438, where 1.438 is the ratio of EtOH mole weight to MeOH mole weight. x(EtOH) is the mole fraction of EtOH and is defined as follows: x(EtOH) = n(EtOH) / (n(MeOH) + n(EtOH)), where n(ROH) is the number of moles of the alcohol ROH. ROH is any of EtOH (ethanol) or MeOH (methanol).

[0019] Within the above ranges, the yield of higher olefins, expressed as C5+ hydrocarbons, more specifically as C5+ olefins, is higher than when using the two alcohols as feed, separately, i.e. where the alcohol feed is either a C2-C8 stream e.g. an EtOH stream, or a MeOH stream. At the same time, the content of lighter hydrocarbons, these being C3-C4 olefins and ethylene (C2 olefin), thus C2-C4 olefins, is kept at a reasonable low level, as shown in appended Fig. 1. It has been found, that as the proportion of EtOH in the alcohol feed stream increases (e.g. increasing x(EtOH)), the higher becomes the production of ethylene, while the production of C3-C4 olefins as well as the desired C5+ olefins decreases. At the above ranges of x(EtOH) the proportion of C5+ olefins is the highest, while the light hydrocarbons (C3-C4 olefins and ethylene) is lowest.

[0020] In an embodiment, the C2-C8 alcohol is ethanol (EtOH) and the weight ratio of EtOH to MeOH is 0.36-0.62, such as 0.36-0.48, corresponding respectively to the mole fraction of EtOH (x(EtOH)) in the range 0.20-0.30, such as 0.20-0.25. At these ranges, there is a low proportion of ethylene being produced, while maintaining a high proportion of C5+ olefins and an acceptably low proportion of C3-C4 olefins, in particular a low proportion of C3-olefin. The provision of C4-olefins, together with C5+ olefins, such as C5- C8 olefins or C5-C9 olefins, for later oligomerization is advantageous compared to the provision of C3-olefin (propylene). Ethylene, as discussed, is notoriously the least reactive olefin and thus is kept at the lowest possible value.

[0021] The term “C2-C8 alcohol” means any of C2, C3, C4, C5, C6, C7, C8 alcohol, or combinations thereof. A particular range is a C2-C4 alcohol. A particular example is ethanol (EtOH), i.e. C2 alcohol.

[0022] The term “MeOH” means methanol. The term “EtOH” means ethanol.

[0023] The term “first aspect” or “first aspect of the invention” means process of the invention. The term “second aspect” or “second aspect of the invention” means plant according to the invention.

[0024] Unless otherwise specified, any given percentages content are % by volume. All feeds are preheated as required.

[0025] The term “synthesis gas” (abbreviated to “syngas”) is meant to denote a gas comprising hydrogen and a carbon oxide, and optionally small amounts of other gasses, such as argon, nitrogen, methane, etc. Hence, syngas may also be understood as a mixture of CO and H2, often in combination with CO2 and / or H2O. For the purposes of the present application, the term syngas is to be understood in its broadest sense as any mixture of CO, CO2, H2 and H2O, possibly also containing gases which are inert to the reaction conditions such as Ar, N2 and CH4.

[0026] The term “a carbon oxide” means CO and / or CO2.

[0027] The term “and / or” means in connection with a given embodiment any of three options. The term “and / or” may be used interchangeably with the term “at least one of” the three options.

[0028] The term “reforming” and “steam reforming” are used interchangeably.

[0029] The term “at least a portion” of a given stream, means the entire stream or a portion thereof.

[0030] The term “ATO” means alcohol to olefin conversion. A specific embodiment of ATO is MTO, methanol to olefin conversion.

[0031] The term “OU” means oligomerization of olefins.

[0032] The term “HYDRO” means hydrogenation of oligomerized olefins.

[0033] The term “ATH section” means the alcohol to hydrocarbons section of the hydrocarbon synthesis plant. The hydrocarbon may be an olefin stream, such as a first product rich in olefins. The hydrocarbon may be a jet fuel stream, such as a raw product stream containing hydrocarbons boiling in the jet fuel boiling range. The ATH section comprises an ATO section and may further comprise an OLI section. The ATH section may further comprise a fractionation section and hydroprocessing section, e.g. a hydrogenation reactor. The ATO section comprises an ATO reactor. The OLI section comprises and OLI reactor. The ATO section may comprise a first product separation unit. The OLI section may comprise a second product separation unit.

[0034] The terms “system”, “plant” i.e. process plant, may be used interchangeably. Throughout this specification, the term system is used for the reforming, hence the term “reforming system”.

[0035] The terms “section” and “unit” refers normally in this specification to a subset of a plant or system.

[0036] The term “reaction zone” means a physically delimited space where a catalytic reaction takes place and thus comprising a catalyst. For instance, an adiabatic fixed bed, or a reactor comprising an adiabatic fixed bed.

[0037] The term “suitably” may be given the same meaning as “optionally”, i.e. an optional embodiment.

[0038] The term “comprising” include “comprising only” i.e. consisting of.

[0039] The terms “comprising” and “containing” are used interchangeably.

[0040] The term “invention” or “present invention” is used interchangeably with the term “application” or “present application”.

[0041] The use the use of the article “a” or “an” means one or more. For instance, the term “a hydrogenation reactor” means one or more hydrogenation reactors.

[0042] The term “hydrocarbons boiling in the naphtha boiling range may be used interchangeably with the term “naphtha” and means C5-C9 hydrocarbons boiling in the range 30- 160°C, such C5-C8 hydrocarbons, e.g. C5-C8 olefins. The term “naphtha” is sometimes used interchangeably with the term “naphtha stream” or “intermediate naphtha stream”.

[0043] The term “hydrocarbons boiling in the diesel boiling range” may be used interchangeably with the term “diesel” and means C8-C25 hydrocarbons boiling in the range 120- 360°C, for instance 160-360°C.

[0044] The term “hydrocarbons boiling in the jet fuel range” may be used interchangeably with the term “jet fuel hydrocarbons” or “jet fuel range hydrocarbons”, or respectively, “jet fuel” or “jet fuel range”. The term means C8-C19 hydrocarbons, such as C8-C17 or C8- C16 hydrocarbons, boiling in the range 130-300°C. For instance, the jet fuel is sustainable aviation fuel (SAF) in compliance with ASTM D7566 and ASTM D4054. The term boiling in a given range, shall be understood as a hydrocarbon mixture of which at least 80 wt% boils in the stated range.

[0045] Other definitions are provided throughout the patent application in connection with the recital of one or more embodiments of the invention.

[0046] In an embodiment, the alcohol feed stream is said C2-C8 alcohol stream and a MeOH stream are supplied separately (option ii), and the C2-C8 alcohol stream and the MeOH stream are supplied to the ATO reactor at distinct feeding points, i.e. distinct positions, by feeding the C2-C8 alcohol stream at a position downstream the feeding point of said MeOH stream.

[0047] This further eliminates the associated problem of temperature drop associated with e.g. EtOH dehydration explained above. In addition, the provision of separate feeding points minimizes the inlet temperature to the ATO reactor and / or reduces the recycle- to-makeup ratio, thereby the capacity of the associated recycle compressor where the ATO section is provided as a loop (ATO-loop section), and thereby also improving the yield of higher (C5+) olefins. The recycle-to-makeup ratio means the ratio of first overhead recycle in the ATO section to e.g. the methanol stream being supplied to the ATO reactor. This recycle, herein also referred to as recycle overhead stream, is required for diluting the feed and is provided by a recycle compressor. The present invention enables less recycle and thus less compression energy. This is highly advantageous, as the size of the recycle compressor often may determine the capacity of the plant.

[0048] The delayed provision of the C2-C8 alcohol, e.g. EtOH, by introducing the e.g. EtOH downstream the feeding point of MeOH can be accomplished by several different reactor designs, as for instance shown in appended Fig. 3. For instance, the MeOH feed is introduced at the top of the ATO reactor and the EtOH feed is introduced mid-way down, i.e. in the most downstream portion of the ATO reactor. The reactor inlet temperature is thus reduced compared to when simply using a combined MeOH / EtOH feed. The term “most downstream portion of the ATO reactor” means 25% or more along the length direction of the ATO reactor, such as the most downstream half of the ATO reactor, the most downstream third or most downstream fourth of the ATO reactor. The length of the reactor is the sum of the lengths along the length axis of the ATO reactors) comprising a first and subsequent adiabatic fixed bed reaction zones.

[0049] The feeding point of the C2-C8 alcohol stream, e.g. EtOH stream, is the position in the ATO reactor where the C2-C8 alcohol stream, is supplied and allowed to combine with a raw first product from an upstream bed to which MeOH is separately supplied. The raw first product comprises olefins, such as C5+ olefins and / or C2-C4 olefins, as well as unconverted MeOH.

[0050] In an embodiment, the ATO reactor is provided with at least two adiabatic fixed bed reaction zones as a first adiabatic fixed bed reaction zone and a subsequent adiabatic fixed bed reaction zone, wherein the first adiabatic fixed bed reaction zone e.g. an upper bed, is supplied with said MeOH stream, and the subsequent adiabatic fixed bed reaction zone provided downstream is supplied with said C2-C8 alcohol stream, e.g. EtOH stream.

[0051] This enables flexibility in the provision of the conversion catalyst in the ATO reactor, as the amount of catalyst required in the upper first adiabatic fixed bed reaction zone being fed with MeOH, may for instance be less than the amount of catalyst required in the lower second adiabatic fixed bed reaction zone being fed with e.g. EtOH and a raw first product produced in the upper bed. It has been found that e.g. EtOH, despite having two carbon atoms instead of only one carbon atom for MeOH, actually produces a higher proportion of short chain hydrocarbons, such as light olefins having carbon number lower than three, in particular ethylene (C2=) when the C2-C8 alcohol is EtOH, compared to MeOH. A higher amount of the conversion catalyst may thus be needed in the lower bed to promote the production of higher olefins when the higher alcohol feed (C2-C8 alcohol) is provided. For instance also, a more reactive catalyst is provided in the lower second adiabatic fixed bed reaction zone.

[0052] In an embodiment, the first adiabatic fixed bed reaction zone comprises one or more beds.

[0053] In an embodiment, the subsequent adiabatic fixed bed reaction zone comprises one or more beds, and any of said beds is supplied with said C2-C8 alcohol stream; for instance, a first C2-C8 alcohol stream is supplied to a first bed of said subsequent adiabatic fixed bed reaction zone, and a second C2-C8 alcohol stream is supplied to a downstream bed of said subsequent adiabatic fixed bed reaction zone.

[0054] This further enables reducing the impact of sudden and steep drop of the inlet temperature to the ATO reactor, thereby reducing the risk of extinguishing the reaction(s) for converting the oxygenates to hydrocarbons.

[0055] In an embodiment, a raw first product rich in olefins is withdrawn from the first adiabatic fixed bed reaction zone and combined with the C2-C8 alcohol stream prior to being supplied to the subsequent adiabatic fixed bed reaction zone.

[0056] The first adiabatic fixed bed reaction zone may also be referred to as “upper bed(s)”. The subsequent adiabatic fixed bed reaction zone may also be referred to as “lower bed(s)”.

[0057] The feed to the lower bed thus combines the C2-C8 alcohol e.g. EtOH, with any unconverted MeOH from the upper bed and the raw first product rich in olefins. This further enables a better mixing of the feed stream. Furthermore, by introducing the C2-C8 alcohol part of the feed stream in a lower bed, the overall temperature profile in the reactor (upper and lower beds) becomes more flat, i.e. with a lower difference between maximum and minimum temperature.

[0058] In an embodiment, the first adiabatic fixed bed reaction zone is a first ATO reactor, and the subsequent adiabatic fixed bed reaction zone is a second ATO reactor provided downstream.

[0059] In an embodiment, the inlet temperature of the alcohol feed stream to the ATO reactor is 275°C or higher, and the outlet temperature of said first product rich in olefins is 475°C or lower; and / or

[0060] - the pressure of the ATO is at least 10 barg, such as 10-120 barg, e.g. 15-120 barg, 20-100 barg, or 20-80 barg; and / or - said 1-D pore structure of the conversion catalyst is any of *MRE (ZSM-48), MTT (ZSM-23), TON (ZSM-22), or combinations thereof.

[0061] Suitably, the inlet temperature is 275-375°C and the outlet temperature which is higher than said inlet temperature is 325-475°C. For instance, the outlet temperature is 375°C or lower. For instance, the inlet temperature is 275-325°C such as 290°C or 300°C.

[0062] These conditions further enable the production of hydrocarbons in the ATO reactor having already a large proportion of C5+ olefins, such as C5-C9 or C5-C8 olefins, as well as C4-olefins, as explained above.

[0063] Suitably, the adiabatic temperature rise in the one or more downstream adiabatic fixed bed reaction zones is 30-100°C, thus the reaction temperature and thereby the average reaction zone temperature, such as the average bed temperature, is in between the inlet and outlet temperature. As inferred from earlier, the feeding approach in which the feeding of e.g. EtOH is delayed with respect to MeOH, enables also reducing this adiabatic temperature rise across the reactor.

[0064] Suitably, for an isothermal reactor, the temperature is between 275°C and 475°C, such as 300, 350, 400, 450°C.

[0065] The 1-D pore structure of the conversion catalyst is any of *MRE (ZSM-48), MTT (ZSM-23), TON (ZSM-22), or combinations thereof. It would be understood that the term “*MRE (ZSM-48)” refers to zeolite type materials and means that the term “*MRE” and “ZSM-48” may be used interchangeably. The same applies for the terms MTT (ZSM-23), TON (ZSM-22). It has been found that this type of zeolite in the catalyst, provides the best results in terms of producing the desired hydrocarbons in the jet fuel range.

[0066] A zeolite with a framework having a 10-ring pore structure means a pore circumference defined by 10 oxygens.

[0067] A 1-D pore structure means zeolites containing non-intersecting pores that are substantially parallel to one of the axes of the crystal. The pores preferably extend through the zeolite crystal. The three letter code, e.g. *MRE, for structure types are 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.

[0068] It would be understood that the term “ZSM-48” may be used interchangeably with the term “EU-2”.

[0069] In an embodiment, the zeolite i.e. the 1-D 10 ring pore structure zeolite, such as ZSM- 48, has a silica-to-alumina ratio (SAR) of up to 240.

[0070] In an embodiment, the ATO reactor is operated at a weight hour space velocity (WHSV) of 0.1-5 h’1, such as 0.3-4 h’1, e.g. 0.5-2 h’1, for instance 1 , 1.5, 2 h’1. It would be understood that WHSV is measured as: kg of oxygenate / kg catalyst / h.

[0071] In an embodiment, the process further comprises a prior step of:

[0072] - supplying any of a biomass feed, an industrial off-gas containing carbon oxides, a municipal solid waste feed, or combinations thereof, to a fermentation reactor for producing said C2-C8 alcohol stream, preferably as a C2-alcohol stream (EtOH stream), the fermentation reactor further producing a CO2 byproduct stream; wherein the process further comprises:

[0073] - withdrawing at least a portion of said industrial off-gas containing carbon oxides, suitably a CC>2-stream thereof; or withdrawing at least a portion of said CO2 byproduct stream;

[0074] - providing a H2-stream, suitably by supplying a water feedstock, i.e. water or steam, to an electrolysis unit for producing an Ch-stream and said H2-stream;

[0075] - supplying the CCh-stream and / or said CO2 byproduct stream, and the H2-stream, optionally after mixing, to a methanol synthesis section (MeOH section) for producing said MeOH stream.

[0076] Hence, at least some of the methanol is produced from CO2, optionally the CO2 produced as a by-product from fermentation of biomass to produce ethanol, here as bioethanol, which decreases the overall CO2 footprint compared to a pure bio-ethanol to jet fuel process. It should be noted that the CCh-stream inherently arising as a byproduct from fermentation processes, i.e. said CO2 byproduct stream, is biogenic by nature, concentrated and very pure. This is highly advantageous for CCh-conversion processes, since the amount of energy needed for purification is considerably lower than from most other sources. Fermentation of biomass produces one mole of CO2 per mole of ethanol. As this CO2 is used for making methanol (along with H2 from e.g. water or steam electrolysis), the methanol / ethanol ratio will be 1 on a molar basis. In some cases, however, part of the CO2 or part of the ethanol may be used for other purposes, thus resulting in MeOH / EtOH molar ratios deviating from 1. Therefore, it is a significant advantage that the present invention provides flexibility regarding the MeOH / EtOH ratio and thus different front-end options for producing MeOH and C2-C8 alcohols such as EtOH. Different embodiments of the invention enable to achieve methanol / ethanol molar ratios deviating from 1 .

[0077] “Bio-ethanol” means ethanol produced from biomass in a fermentation process. “Fermentation” means fermentation of biomass feed and signifies a process in which carbohydrates are converted to ethanol and CO2 by microorganisms. An example of the reaction is CeH^Oe = 2C2H5OH + 2CO2.

[0078] “Biomass feed” means any biological material which is not or cannot be converted to bio-ethanol in an efficient way and which therefore can be considered as waste in the present context. Examples are fermentation mash and lignin.

[0079] “Municipal solid waste feed” means a feedstock containing materials of items discarded by the public, such as mixed municipal waste given the waste code 200301 in the European Waste Catalog (EWC code 20 03 01); or mixed recycled solid waste given in EU Directive 2018 / 2001 (RED II), Annex IX, Part A.

[0080] “Industrial off-gas containing carbon oxides” means any off-gas containing CO and / or CO from an industrial process. For instance, from biogas upgrading, or from a natural gas-based plant for producing syngas, or from a natural gas-based plant for producing syngas and further for producing hydrocarbons such as gasoline or diesel, or where CO2 is extracted from waste heat sections or fired heater flue gases and utilized for making more syngas with the method according to the present invention. For instance, sources of said industrial off-gas containing carbon oxides include heat and power plants and waste incineration plants.

[0081] For instance, biogas upgrading means more specifically the cleaning and upgrading to natural gas standards as bio-methane. Biogas is a renewable energy source that can be used for heating, electricity, and many other operations. Biogas is primarily methane (CH4) and carbon dioxide (CO2), typically containing 60-70% vol. methane. Up to 30% or even 40% of the biogas may be carbon dioxide. Typically, this carbon dioxide is removed from the biogas and vented to the atmosphere in order to provide a methane rich gas for further processing or to provide it to a natural gas network. The removed CO2 is suitably utilized as an industrial off-gas containing carbon oxides according to the present invention.

[0082] The MeOH section comprises a methanol synthesis reactor.

[0083] The MeOH section is suitably a methanol synthesis loop (MeOH loop). A MeOH loop comprises the methanol synthesis reactor, a separation unit for producing a raw methanol product stream, a process condensate stream and an overhead recycle stream, in which at least a portion of the overhead recycle stream is sent to inlet of methanol synthesis reactor, suitably in combination with a syngas being fed thereto.

[0084] In an embodiment, the process further comprises:

[0085] - withdrawing from said ATH synthesis section, optionally from said MeOH section, a by-product stream rich in C1-C4 paraffins and / or olefins, such as any of: methane, ethane, ethene (ethylene), propane, propene (propylene), butane, butene (butylene, and combinations thereof;

[0086] - supplying at least a portion of said by-product stream rich in C1-C4 paraffins and / or olefins, to any of: a reforming system comprising a reforming unit (reformer), performing a reforming step in said reforming unit, and providing a reformer-based syngas stream; a gasification section comprising a gasification unit (gasifier), performing a gasification step in said gasification unit, and providing a gasifier-based syngas stream;

[0087] - supplying at least a portion of said reformer-based or gasifier-based syngas stream to the inlet of the methanol synthesis section (MeOH section), in particular to the methanol synthesis reactor therein.

[0088] In an embodiment, said reforming unit is an electrically heated steam methane reformer (e-SMR). In an embodiment, said reforming unit is an autothermal reformer (ATR) and at least a portion of said Ch-stream is supplied to said ATR or said gasification unit (gasifier).

[0089] The ATR and gasification technologies are well-known in the art. For instance, more details of ATR and a full description can be found in the art such as “Studies in Surface Science and Catalysis, Vol. 152,” Synthesis gas production for FT synthesis”; Chapter 4, p.258-352, 2004”. For a description of e-SMR which is a more recent technology, reference is given to e.g. applicant’s WO 2019 / 228797 A1.

[0090] The provision of reformer-based or gasifier-based syngas stream to the inlet of the methanol synthesis unit enables a more reactive synthesis gas being fed to the methanol synthesis reactor. The reformer-based or gasifier-based syngas contains a significant amount of CO, which enables to tailor the synthesis gas to the methanol synthesis unit to have the required module M of about 2, as further defined below, while at the same time providing a high CO / CO2 molar ratio. The high CO / CO2 molar ratio renders a much more reactive syngas for methanol synthesis, as there is a higher yield of methanol while at the same time the catalyst volume is significantly reduced, and not least the production of water is also significantly reduced. The productivity in terms of MeOH space-time yield for e.g. a traditional usual Cu / ZnO / AhCh MeOH synthesis catalysts is improved. Thereby also, a smaller MeOH loop is provided.

[0091] In an embodiment, the process further comprises:

[0092] - said fermentation reactor producing a bio-waste stream comprising any of mash and lignin, and supplying at least a portion thereof to said gasification unit.

[0093] Bio-waste stream means any biological material which is not or cannot be converted to bio-ethanol in an efficient way in the fermentation reactor and which therefore can be considered as waste in the present context. Examples are mash and lignin.

[0094] Thereby, the invention enables also to take advantage of waste streams produced in the process and extract further value for producing methanol, which is one of the required feedstock in the process. In an embodiment, at least a portion of the CCh-stream and / or said CO2 byproduct stream is electrolyzed together with steam, i.e. co-electrolysis, thereby providing a stream comprising CO and CO2; and mixing it with said H2-stream, thereby providing a syngas enriched in CO.

[0095] A syngas enriched in CO, as described above, is highly advantageous.

[0096] In an embodiment, the ATO section comprises a first product separation unit; the ATH synthesis section comprises:

[0097] - an oligomerization (OLI) section, said OLI section comprising an OLI reactor, optionally, a second product separation unit;

[0098] - a fractionation section i.e a final product separation section;

[0099] - a hydroprocessing section, suitably a hydrogenation section; and the process further comprises:

[0100] - supplying said first product rich in olefins from the ATO reactor to said first product separation unit, and withdrawing therefrom at least a first recycle overhead stream and a first raw hydrocarbon product stream;

[0101] - supplying said first product rich in olefins from the ATO reactor and / or said first raw hydrocarbon product stream to the OLI reactor of said OLI section and further to said fractionation section; and withdrawing from said fractionation section: at least an intermediate naphtha stream and an intermediate jet fuel stream, optionally an intermediate diesel stream, optionally also a by-product stream rich in C1 -C4 paraffins and / or olefins, such as any of: methane, ethane, ethene (ethylene), propane, propene (propylene), butane, butene (butylene), and combinations thereof;

[0102] - supplying at least said intermediate jet fuel stream to said hydroprocessing section, suitably to said hydrogenation section, and withdrawing therefrom a jet fuel product.

[0103] For instance, from the OLI reactor a second product rich in olefins is provided and which comprises 05+ hydrocarbons of which at least 30 wt% are hydrocarbons boiling in the jet fuel boiling range; preferably, at least 40 wt%, or at least 45 wt%, or least 50 wt% of said 05+ hydrocarbons are said hydrocarbons boiling in the jet fuel boiling range. For instance, 40, 50, 60, 70, 80 or 90 wt%; such as 40-60 wt%, or 45-55 wt of said 05+ hydrocarbons are said hydrocarbons boiling in the jet fuel boiling range. Suitably, said hydrocarbons boiling in the jet fuel boiling range are C8-C19 hydrocarbons, such as C8-C17 or C8-C16 hydrocarbons.

[0104] The oligomerization is for instance conducted by conventional methods including the use of an oligomerization catalyst such as solid phosphoric acid (“SPA”), ion-exchange resins or a zeolite catalyst, for instance a conventional *MRE, BEA, FAU, MTT, TON, MFI and MTW catalyst, at a pressure of 30-100 bar, such as 50-100 bar, and a temperature of 100-350°C.

[0105] In a second aspect, the invention encompasses also a plant for carrying out the process according to any of the above embodiments.

[0106] Accordingly, there is provided a plant for producing hydrocarbons, comprising:

[0107] - an alcohol-to-hydrocarbons (ATH) synthesis section arranged to receive an alcohol feed stream, said ATH-synthesis section comprising an alcohol-to-olefins (ATO) section, said ATO section comprising an alcohol-to-olefin (ATO) reactor; said alcohol feed stream being any of : i) a combination of a C2-C8 alcohol stream and a methanol (MeOH) stream; ii) a C2-C8 alcohol stream and a MeOH stream being supplied separately; iii) a combination thereof; in which the weight ratio of the C2-C8 alcohol to methanol (MeOH) in any of said alcohol feed streams is in the range 0.30-6.0;

[0108] - the ATO reactor being arranged to receive said alcohol feed stream and provide a first product rich in olefins as said hydrocarbons; the ATO reactor comprising an adiabatic fixed bed reaction zone having a conversion catalyst comprising a zeolite with a framework having a 10-ring pore structure, said 10-ring pore structure being a unidimensional (1 D) pore structure; and providing a first product rich in olefins as said hydrocarbons;

[0109] - optionally, the alcohol feed stream is provided as a separate C2-C8 alcohol stream and a separate MeOH stream, and the ATO reactor is arranged to receive the C2-C8 alcohol stream and the MeOH stream at distinct feeding points by the ATO reactor being arranged to receive the C2-C8 alcohol stream at a position downstream the feeding point of said MeOH stream. It would be understood that any of the embodiments according to the first aspect of the invention (process) and associated benefits may be used in connection with the second aspect of the invention (plant), or vice versa.

[0110] BRIEF DESCRIPTION OF FIGURES

[0111] Fig. 1 shows the product distribution at 400°C and 440°C respectively, in an ATO reactor, as function of the MeOH / EtOH feed ratio, in accordance with Example 1.

[0112] Fig. 2 shows the relative temperature profile in the ATO reactor on delayed introduction of EtOH feed, in accordance with Example 1 (E1) and comparative examples 1 (CE 1) and 2 (CE 2).

[0113] Fig. 3 shows three different reactor configurations allowing for introduction of feed at separate points in the ATO reactor.

[0114] Fig. 4 shows a block diagram of a process or plant layout illustrating an embodiment of the invention.

[0115] DETAILED DESCRIPTION OF FIGURES

[0116] EXAMPLE 1

[0117] Different feed compositions varying the MeOH / EtOH molar ratio were converted to olefins in bench-scale quasi-isothermal reactor (bench-scale ATO reactor) using ZSM-48 as catalyst. Results are displayed in Figure 1 , which shows product distributions at 400°C (top) and 440°C (right) using different MeOH / EtOH feed compositions. X(EtOH) is the mole fraction of ethanol; x(EtOH) = n(EtOH) / (n(MeOH) + n(EtOH)) where n(ROH) is the number of moles of the alcohol ROH. ROH is any of EtOH (ethanol) or MeOH (methanol). It is observed that by limiting the EtOH / MeOH ratio to the range 0.36-5.75, preferably 0.43-4.55 kg EtOH / kg MeOH. Within this range, which for the former corresponds to x(EtOH)=0.20-0.80, and for the latter x(EtOH)= 0.23-0.76, the yield of higher olefins is higher than when using either MeOH or EtOH as feed; i.e. a synergistic effect is thereby provided. Further, in the narrower range x(EtOH)=0.20-0.30, such as 0.20- 0.25, corresponding to a weight ratio of EtOH to MeOH of 0.36-0.62 and 0.36-0.48, respectively, there is a low proportion of ethylene while maintaining a high proportion of C5+ olefins (C5+ =) and an acceptably low proportion of C3-C4 olefins, in particular a low proportion of C3-olefin (C3=) i.e. propylene. The provision of C4-olefins (C4=), together with C5+ olefins, such as C5-C8 olefins or C5-C9 olefins, for later oligomerization is advantageous compared to the provision of propylene.

[0118] EXAMPLE 2

[0119] Fig. 2 shows a calculated temperature profile in the ATO reactor on delayed introduction of EtOH feed. Example 1 (E1): by introducing the EtOH feed downstream the feeding point of the MeOH stream, here at 50% bed length (halfway the reactor length), the difference between minimum and maximum temperature in the ATO reactor is less than in comparative example 1 (CE 1). Comparative example 2 (CE 2) shows extinction of the reaction where the same inlet temperature as in E1 is chosen but without delayed introduction of the EtOH feed. T(inlet): inlet temperature.

[0120] Now turning to Fig. 3, three different reactor configurations are shown with a feeding point of the EtOH being downstream the feeding point of the MeOH stream in the ATO reactor, here halfway the reactor length in the three configurations. For instance, the first configuration (left) shows a conduit, e.g. a pipe within a larger pipe, for the delayed and thus separate feeding of the EtOH stream. The feeding point of the EtOH stream is the position in the ATO reactor where the EtOH stream is supplied and allowed to combine with a raw first product from an upstream bed to which the MeOH stream is separately supplied.

[0121] Now turning to Fig. 4, a block diagram is shown which illustrates a process / plant 100, where fermentation of biomass is used for producing the EtOH feed and the CO2 obtained as a byproduct from the fermentation is used for obtaining the MeOH feed using H2 from electrolysis. This embodiment has a particularly low carbon footprint and all carbon used is biogenic. In the figure, even reference numerals refer to a process step or associated unit, while uneven numerals refer to process streams. A biomass feed 1 is supplied to a fermentation step 10 in a fermentation reactor for producing EtOH 3 and CO2 byproduct 5. A water feedstock 9, i.e. water or steam, is supplied to an electrolysis step 12 in an electrolysis unit powered by renewable sources such as wind or solar (not shown) to provide hydrogen 11 . The CO2 byproduct 5 and the hydrogen 11 are combined and supplied to a methanol synthesis section (MeOH section) for producing MeOH 7. In the alcohol to hydrocarbons synthesis section (ATH synthesis section), which comprises an ATO section and in which the ATO section comprises an ATO re- actor as for instance shown in Fig. 3, the EtOH 3 and the MeOH 7 are combined and converted into hydrocarbons and then finally separated into jet fuel product 13. From the ATH synthesis section, optionally from said MeOH section, a by-product stream rich in C1 -C4 paraffins and / or olefins, is withdrawn and supplied to a reforming system or gasification section (not shown), thereby providing a reformer-based syngas or gasi- fier-based syngas, respectively, which is supplied to inlet MeOH section (not shown).

Claims

CLAIMS1. A process for producing hydrocarbons, comprising:- supplying an alcohol feed stream to an alcohol-to-hydrocarbons (ATH) synthesis section, said ATH synthesis section comprising an alcohol-to-olefins (ATO) section, said ATO section comprising an alcohol-to-olefin (ATO) reactor; said alcohol feed stream being any of: i) a combination of a C2-C8 alcohol stream and a methanol (MeOH) stream; ii) a C2-C8 alcohol stream and a MeOH stream being supplied separately; iii) a combination thereof;- supplying said alcohol feed stream to the ATO reactor, the ATO reactor comprising an adiabatic fixed bed reaction zone having a conversion catalyst comprising a zeolite with a framework having a 10-ring pore structure, said 10-ring pore structure being a unidimensional (1 D) pore structure; and providing a first product rich in olefins as said hydrocarbons; wherein the weight ratio of the C2-C8 alcohol to methanol (MeOH) in any of said alcohol feed streams is in the range 0.30-6.0.

2. Process according to claim 1 , wherein said C2-C8 alcohol is a C2-C4 alcohol.

3. Process according to any of claims 1-2, wherein said first product rich in olefins comprises: at least 20 vol% C4-olefins; and at least 25 vol% C5+ hydrocarbons of which at least 20 vol% are C5-C8 olefins.

4. Process according to any of claims 1-3, wherein the C2-C8 alcohol is ethanol (EtOH) and the weight ratio of EtOH to MeOH is 0.36-5.75, such as 0.43-4.55.

5. Process according to any of claims 1-4, wherein the C2-C8 alcohol is ethanol (EtOH) and the weight ratio of EtOH to MeOH is 0.36-0.62, such as 0.36-0.48.

6. Process according to any of claims 1-5, wherein the alcohol feed stream is said C2- C8 alcohol stream and a MeOH stream being supplied separately, and wherein the C2- C8 alcohol stream and the MeOH stream are supplied to the ATO reactor at distinct feeding points, by feeding the C2-C8 alcohol stream at a position downstream the feeding point of said MeOH stream.

7. Process according to claim 6, wherein the ATO reactor is provided with at least two adiabatic fixed bed reaction zones as a first adiabatic fixed bed reaction zone and a subsequent adiabatic fixed bed reaction zone, wherein the first adiabatic fixed bed reaction zone e.g. an upper bed, is supplied with said MeOH stream, and the subsequent adiabatic fixed bed reaction zone provided downstream is supplied with said C2-C8 alcohol stream.

8. Process according to claim 7, wherein the subsequent adiabatic fixed bed reaction zone comprises one or more beds, and any of said beds is supplied with said C2-C8 alcohol stream; for instance, a first C2-C8 alcohol stream is supplied to a first bed of said subsequent adiabatic fixed bed reaction zone, and a second C2-C8 alcohol stream is supplied to a downstream bed of said subsequent adiabatic fixed bed reaction zone.

9. Process according to any of claims 7-8, wherein a raw first product rich in olefins is withdrawn from the first adiabatic fixed bed reaction zone and combined with the C2- C8 alcohol stream prior to being supplied to the subsequent adiabatic fixed bed reaction zone.

10. Process according to any of claims 1-9, wherein:- the inlet temperature of the alcohol feed stream to the ATO reactor is 275°C or higher, and the outlet temperature of said first product rich in olefins is 475°C or lower; and / or- the pressure of the ATO is at least 10 barg, such as 10-120 barg, e.g. 15-120 barg, 20-100 barg, or 20-80 barg; and / or- said 1-D pore structure of the conversion catalyst is any of *MRE (ZSM-48), MTT (ZSM-23), TON (ZSM-22), or combinations thereof.11 . Process according to any of claims 1-10, wherein the process further comprises a prior step of:- supplying any of a biomass feed, an industrial off-gas containing carbon oxides, a municipal solid waste feed, or combinations thereof, to a fermentation reactor forproducing said C2-C8 alcohol stream, preferably as a C2-alcohol stream (EtOH stream), the fermentation reactor further producing a CO2 byproduct stream; wherein the process further comprises:- withdrawing at least a portion of said industrial off-gas containing carbon oxides, suitably a CC>2-stream thereof; or withdrawing at least a portion of said CO2 byproduct stream;- providing a H2-stream, suitably by supplying a water feedstock, i.e. water or steam, to an electrolysis unit for producing an Ch-stream and said H2-stream;- supplying the CCh-stream and / or said CO2 byproduct stream, and the H2-stream, optionally after mixing, to a methanol synthesis section (MeOH section) for producing said MeOH stream.

12. Process according to any of claims 1-11 , wherein the process further comprises:- withdrawing from said ATH synthesis section, optionally from said MeOH section, a by-product stream rich in C1-C4 paraffins and / or olefins, such as any of: methane, ethane, ethene (ethylene), propane, propene (propylene), butane, butene (butylene), and combinations thereof;- supplying at least a portion of said by-product stream rich in C1-C4 paraffins and / or olefins, to any of: a reforming system comprising a reforming unit (reformer), performing a reforming step in said reforming unit, and providing a reformer-based syngas stream; a gasification section comprising a gasification unit (gasifier), performing a gasification step in said gasification unit, and providing a gasifier-based syngas stream;- supplying at least a portion of said reformer-based or gasifier-based syngas stream to the inlet of the methanol synthesis section (MeOH section).

13. Process according claim 12, wherein said reforming unit is an electrically heated steam methane reformer (e-SMR); or wherein said reforming unit is an autothermal reformer (ATR) and at least a portion of said 02-stream is supplied to said ATR or said gasification unit (gasifier).

14. Process according to any of claims 11-13, wherein the process further comprising:- said fermentation reactor producing a bio-waste stream comprising any of mash and lignin, and supplying at least a portion thereof to said gasification unit.

15. Process according to any of claims 11-14, wherein at least a portion of the CO2- stream and / or said CO2 byproduct stream is electrolyzed together with steam, i.e. coelectrolysis, thereby providing a stream comprising CO and CO2; and mixing it with said H2-stream, thereby providing a syngas enriched in CO.

16. Process according to any of claims 1-15, wherein the ATO section comprises a first product separation unit; wherein the ATH synthesis section comprises:- an oligomerization (OLI) section, said OLI section comprising an OLI reactor, optionally, a second product separation unit;- a fractionation section;- a hydroprocessing section, suitably a hydrogenation section; and the process further comprising:- supplying said first product rich in olefins from the ATO reactor to said first product separation unit, and withdrawing therefrom at least a first recycle overhead stream and a first raw hydrocarbon product stream;- supplying said first product rich in olefins from the ATO reactor and / or said first raw hydrocarbon product stream to the OLI reactor of said OLI section and further to said fractionation section; and withdrawing from said fractionation section: at least an intermediate naphtha stream and an intermediate jet fuel stream, optionally an intermediate diesel stream, optionally also a by-product stream rich in C1 -C4 paraffins and / or olefins, such as any of: methane, ethane, ethene (ethylene), propane, propene (propylene), butane, butene (butylene), and combinations thereof;- supplying at least said intermediate jet fuel stream to said hydroprocessing section, suitably to said hydrogenation section, and withdrawing therefrom a jet fuel product.

17. Plant for carrying out the process according to any of claims 1-16; comprising:- an alcohol-to-hydrocarbons (ATH) synthesis section arranged to receive an alcohol feed stream, said ATH-synthesis section comprising an alcohol-to-olefins (ATO) section, said ATO section comprising an alcohol-to-olefin (ATO) reactor; said alcohol feedstream being any of : i) a combination of a C2-C8 alcohol stream and a methanol (MeOH) stream; ii) a C2-C8 alcohol stream and a MeOH stream being supplied separately; iii) a combination thereof; in which the weight ratio of the C2-C8 alcohol to methanol (MeOH) in any of said alcohol feed streams is in the range 0.30-6.0; - the ATO reactor being arranged to receive said alcohol feed stream and provide a first product rich in olefins as said hydrocarbons; the ATO reactor comprising an adiabatic fixed bed reaction zone having a conversion catalyst comprising a zeolite with a framework having a 10-ring pore structure, said 10-ring pore structure being a unidimensional (1 D) pore structure; and providing a first product rich in olefins as said hy- drocarbons;- optionally, the alcohol feed stream is provided as a separate C2-C8 alcohol stream and a separate MeOH stream, and the ATO reactor is arranged to receive the C2-C8 alcohol stream and the MeOH stream at distinct feeding points by the ATO reactor being arranged to receive the C2-C8 alcohol stream at a position downstream the feeding point of said MeOH stream.

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