Hydroprocessing of pyrolysis oils

Abstract

The invention relates to the field of hydroprocessing of liquid oils such as pyrolysis oils, more specifically to the stabilization of the liquid oil by hydrotreating prior to being upgraded by further hydroprocessing. More particularly, the invention relates to the stabilization of pyrolysis oil containing polymerisable reactive compounds.

Description

[0001] HYDROPROCESSING OF PYROLYSIS OILS

[0002] TECHNICAL FIELD

[0003] The invention relates to the field of hydroprocessing of liquid oils such as pyrolysis oils, more specifically to the stabilization of the liquid oil by hydrotreating prior either during or prior to final hydroprocessing. More particularly, the invention relates to the stabilization of pyrolysis oil containing polymerisable reactive compounds.

[0004] BACKGROUND

[0005] The field of renewable feedstocks has been attracting a great deal of attention, not only in Europe, but also US and China. Using renewable feedstocks enables a sustainable approach to the production of hydrocarbon products boiling in the transportation fuel range, in particular any of diesel, jet fuel and naphtha as well as petrochemicals, such as raw materials for steam crackers and plastic production.

[0006] Pyrolysis oils from waste plastic primarily comprise saturated hydrocarbons, but also comprise highly unsaturated olefins, diolefins, conjugated diolefins, aromatics, and vinyl- aromatics. These oils further contain heteroatoms like nitrogen, oxygen, sulfur and halogens. The exact nature of the pyrolysis oil depends greatly on the polymer composition of the feedstock used in the liquefaction process. Pyrolysis oils are very unstable and tend to polymerize when heated. This leads to rapid catalyst deactivation and plugging of the catalyst bed of the hydrotreatment reactor, due to coking or gum formation, and hence caution is required to minimize this risk, e.g. by minimizing heating of pyrolysis oils prior to stabilization and ensure presence of sufficient hydrogen to avoid thermal polymerization. At the same time, deposition of salts, such as ammonium chloride, in the pyrolysis oil to the catalyst bed should be avoided.

[0007] In order to fulfil the requirements as petrochemical feedstock (e.g. for steam crackers) the olefinic hydrocarbons must be saturated and the number of heteroatoms must be decreased significantly.

[0008] One standard solution to this problem is to include separate diolefin reactors in a PPO process / plant, so as to saturate the dienes, see e.g. DK PA 2023 00164. The diolefin reactors are arranged in parallel. In case of excessive salt formation in one diolefin reactor, it can be taken out of service and cleaned, while diolefin saturation continues in the other diolefin reactor. However, this solution requires additional equipment, and monitoring of salt formation.

[0009] It is an object to provide a process for hydroprocessing a feed which is the result of pyrolysis of a solid material, being e.g. waste, biological or plastic material, in which the above- mentioned problems are avoided, in particular to remove reactive unsaturated components, while avoiding salt formation. It would also be desirable to provide a process for hydroprocessing a feed, such as a plastic pyrolysis oil (PPO) feed or other pyrolysis oils, that is susceptible to polymerisation that does not lead to significant increases in CAPEX and OPEX. Also, it would be advantageous to reduce or remove the need for separate diolefin reactors.

[0010] In the following a hydrocarbonaceous feedstock shall be used to signify a feedstock rich in molecules comprising hydrogen and carbon, but possibly also heteroatoms, i.e. other elements, such as oxygen, sulfur and nitrogen. A hydrocarbon compound shall be understood as being dominated by hydrocarbons, but not narrowly excluding presence of atoms other than hydrogen and carbon below 1 wt%.

[0011] SUMMARY

[0012] In one aspect a process for hydroprocessing a feed which is the result of pyrolysis of a solid material, is provided. The process comprises the steps of: providing a feed, comprising hydrocarbons, hydrocarbonaceous compounds and at least one polymerizable reactive compound, splitting said feed into at least a first stream and a second stream , providing a fixed bed reactor comprising at least a first reactor bed containing a first hydrotreatment catalyst and a second reactor bed containing a second hydrotreatment catalyst, mixing the first stream with a recycle stream and a hydrogen-rich stream, and feeding the mixed stream to said first catalyst bed of the fixed bed reactor, whereby the polymerizable reactive compounds in the first stream are saturated in a catalytic saturation reaction, feeding the second stream to the second reactor bed of the fixed bed reactor, whereby the polymerizable reactive compounds in the second stream are saturated in a catalytic saturation reaction, wherein said second catalyst bed is located downstream the first catalyst bed, outputting a first hydrocarbon stream from the fixed bed reactor, said first hydrocarbon stream having a lower concentration of polymerizable reactive compounds than the feed, feeding the first hydrocarbon stream to a charge heater and heating it to provide a second hydrocarbon stream, feeding the second hydrocarbon stream to a hydrotreatment reactor and subjecting it to a catalytic hydrotreament step, so as to provide a third hydrocarbon stream from the hydrotreatment reactor, feeding the third hydrocarbon stream to a hot separator where it is separated into at least a gaseous fraction and a liquid fraction, wherein at least a portion of the liquid fraction is used as at least a portion of the recycle stream, and wherein at least a portion of said hydrogen-rich stream is provided by upgrading the gaseous fraction from the hot separator and wherein hydrogen is present in excess of the theoretical hydrogen consumption.

[0013] The present invention also relates to a process plant configured for carrying out the process described herein.

[0014] Further details of the technology are provided in the enclosed dependent claims, figures and examples.

[0015] LEGENDS

[0016] Embodiments of the present invention are explained by way of examples and with reference to the accompanying drawings. The appended drawings illustrate only examples of embodiments of the present invention, and they are therefore not to be considered limiting of its scope, as the invention may admit to other alternative embodiments.

[0017] Fig. 1 shows a process / plant layout according to the invention.

[0018] Fig. 2 shows a further process / plant layout according to the invention. DETAILED DISCLOSURE

[0019] Definitions

[0020] The term "paraffinic hydrocarbon" means any of the saturated linear hydrocarbons having the general formula CnH2n+2, in which n is an integer.

[0021] As noted, a process for hydroprocessing a feed is provided. The feed is the result of pyrolysis of a solid material, being waste, biological or plastic material. Suitably, the feed is a PPO feed. The feed comprises hydrocarbons, such as paraffinic hydrocarbons, and at least one polymerizable reactive compound.

[0022] By the present invention, the feed is stabilized by the conversion of at least the most reactive compounds in the feed, e.g. by saturation of conjugated diolefins and styrene homologues. The present invention provides a process for this stabilisation whilst circumventing issues associated with coking of the catalyst bed as a result of the reaction of polymerisable reactive compounds, such as diolefins, within the feed at the temperatures employed. In particular, the process of the present invention provides an arrangement in which an intermediate reactor shut-down can be avoided by having a reactor configurable for by-pass of a first reactor bed. This in turn provides a process for hydrotreating a feed that does not lead to significant increases in CAPEX and / or OPEX. Additionally, configuring a second downstream reactor operating at a higher temperature for by-passing a reactor bed in a similar way, may be beneficial under some circumstances.

[0023] As its name suggests, the feed is derived - at least partly - from pyrolysis of plastic waste. As used herein, the term "pyrolysis" is used to define a decomposition process, in which a material is partially decomposed at elevated temperature (typically 250°C to 800°C or even 1000°C), in the presence of a substoichiometric amount of oxygen (including no oxygen). The product will typically be a combined liquid and gaseous stream, as well as an amount of solid char. Pyrolysis may be both in the presence and absence of a catalyst.

[0024] Pyrolysis is conducted in a pyrolysis section. The pyrolysis section may be in the form of a fluidized bed, transported bed, or circulating fluid bed, as is well known in the art. For instance, the pyrolysis section may comprise a pyrolyser unit (pyrolysis reactor), cyclone(s) to remove particulate solids such as char, and a cooling unit for thereby producing said pyrolysis off-gas stream and said pyrolysis oil stream, i.e. condensed pyrolysis oil. The pyrolysis off-gas stream comprises light hydrocarbons e.g. C1-C4 hydrocarbons, CO and CO2. The pyrolysis oil stream is also referred to as a liquid substance rich in blends of molecules including saturated and unsaturated hydrocarbons, cyclic and aliphatic, as well as hydrocarbons that contain heteroatoms like nitrogen, oxygen, halogens and sulfur. Hydrocarbons that contain heteroatoms includes nitriles, amines, amides, thioles, sulfides, thiophenes, aldehydes, ketones and / or other compounds such as furfural having a carbonyl group, resulting from the depolymerization of the feedstock treated in pyrolysis. In one embodiment, therefore, the pyrolysis oil stream from the pyrolysis section is used as feed for the invention. According to the invention, the feed comprises hydrocarbon, such as paraffinic hydrocarbons, and at least one polymerizable reactive compound.

[0025] For the purpose of the present invention, the pyrolysis is preferably fast pyrolysis or slow pyrolysis. Fast pyrolysis means the thermal decomposition of a solid renewable feedstock in the absence of oxygen, at temperatures in the range 350-650°C e.g. about 500°C and reaction times of 10 seconds or less, such as 5 seconds or less, such as about 2 seconds or less. Fast pyrolysis may for instance be conducted by autothermal operation e.g. in a fluidized bed reactor. The latter is also referred to as autothermal pyrolysis and is characterized by employing air, optionally with an inert gas or recycle gas, as the fluidizing gas, or by using a mixture of air and inert gas or recycle gas. Thereby, the partial oxidation of pyrolysis compounds being produced in the pyrolysis reactor (autothermal reactor) provides the energy for pyrolysis while at the same time improving heat transfer. For details about autothermal pyrolysis, reference is made to e.g "Heterodoxy in Fast Pyrolysis of Biomass" by Robert Brown: https: / / dx.doi.orq / 10.1021 / acs.enerqyfuels.0c03512

[0026] "Intermediate" or "slow" pyrolysis are also suitable for feedstocks originating from waste plastics, and may be even more suitable than fast pyrolysis. One reason is that high N containing feedstocks tend to comprise more alkaline metals, which increases the risk of agglomeration and defluidization. In addition, slow pyrolysis is currently the most widespread form of pyrolysis used for plastic waste and gives good oil yields.

[0027] In another embodiment, therefore, the pyrolysis step is intermediate pyrolysis, in which the vapor residence time is in the range of 10 seconds - 5 minutes, such as 11 seconds - 3 minutes. As for fast pyrolysis, the temperature is also in the range 350-650°C e.g. about 500°C. Often this pyrolysis is conducted in pyrolysis reactors handling different types of waste, where the vapor is burned after the pyrolysis reactor. Typical reactors are: Herreshoff furnace, rotary drums, amaron, CHOREN paddle pyrolysis kiln, auger reactor, and vacuum pyrolysis reactor.

[0028] In another embodiment, the pyrolysis step is slow pyrolysis, in which the solid residence time is in the range of 5 minutes - 2 hours, such as 10 min - 1 hour. The temperature is suitably about 300°C. This pyrolysis gives a high char yield and the char can be used as a fertilizer or as char coal; the pyrolysis still produces some gas and renewable crude and if the carbon is used a fertilizer the final bio-oil can have a GHG above 100 %, thus being carbon negative. Typical reactors are auger reactor (yet with a different residence time than for intermediate pyrolysis), fixed bed reactor, kiln, lambiotte SIFIC / CISR retort, Lurgi process, wagon reactor, and carbo twin resort.

[0029] It would therefore be understood, that for the purpose of the present invention, the use of autothermal pyrolysis, i.e. autothermal operation, is a particular embodiment for conducting fast pyrolysis.

[0030] There are several types of fast pyrolysis where a catalyst is used. Sometimes an acid catalyst, such as zeolite or silica-alumina catalysts, is used in the pyrolysis reactor to upgrade the pyrolysis vapors, this technology is called catalytic fast pyrolysis and can both be operated in an in-situ mode (the catalyst is located in the pyrolysis reactor) and an ex-situ mode (the catalyst is placed in a separate reactor). The use of a catalyst conveys the advantage of lowering the activation energy for reactions thereby significantly reducing the required temperature for conducting the pyrolysis. In addition, increased selectivity towards desired pyrolysis oil compounds may be achieved. In some cases, hydrogen is added to the catalytic pyrolysis which is called reactive catalytic fast pyrolysis. If the catalytic pyrolysis is conducted at a high hydrogen pressure (~>5 barg) it is often called catalytic hydropyrolysis and the pyrolysis product will typically contain a lower amount of oxygen, such as 1 wt% to 5 wt%. In one aspect, the pyrolysis stage is fast pyrolysis which is conducted without the presence of a catalyst and hydrogen, i.e. the fast pyrolysis stage is not catalytic fast pyrolysis, hydropyrolysis or catalytic hydropyrolysis. This enables a much simpler and inexpensive process.

[0031] The feed comprises a polymerizable reactive compound, which at above elevated temperatures (>80 °C) but below the temperatures resulting in substantially complete hydrotreatment, may react to form larger molecules, potentially resulting in full or partial blockage of reactors, tubes, heaters, heat exchangers and catalysts.

[0032] Examples of such polymerizable reactive compounds, are conjugated diolefins or styrene and its homologs from thermochemical decomposition of plastic waste. The compounds may either react within the same functional group (for example, diolefin with diolefin) or across functional groups (for example, aldehyde with phenol).

[0033] Suitably, therefore, the feed may comprise at least one polymerizable reactive compound, selected from polyunsaturated hydrocarbons, sugars, carbonyls, styrene homologues, vinyl- aromatics and other polymerisable reactive compounds from biological pyrolysis oil, preferably polyunsaturated hydrocarbons.

[0034] The feed can have a diene value of 2 gI / 100 g to 10 gI / 100 g (e.g. measured by UOP326). Other components of the feed may be sulfur (100 to 1000 wt ppm), chlorine (50 to 1500 wt ppm), nitrogen (100 to 4000 wt ppm), oxygen (500 ppmwt to 1 wt% or even 10 wt%) and olefins (40 to 80 wt%) with a total amount of conjugated di-olefins being 0.5 to 5 or even 10 wt%. These values mainly apply to plastic pyrolysis oils. Hence, in one embodiment of the invention, the feed is a plastic pyrolysis oil feed.

[0035] For pyrolysis oils originating from biological sources, including municipal waste, the composition may commonly be defined by the oxygen content being 3-50 wt% and the ratio between hydrogen and carbon being below 1.8: 1 or even below 1.6: 1. Heteroatoms such as sulfur and nitrogen may be present in elevated amounts, depending on the source.

[0036] The composition of pyrolysis oil from thermal decomposition of artificial polymers may involve 0.5-5 wt% or 0.5-10 wt% of conjugated di-olefins and as much as 30-90 wt% such as 65 wt% olefins. The atomic oxygen content may typically be below 1 wt% such as from 500 ppmwt, but it may be up to 15 wt%.

[0037] In one aspect, the feed has a diene number of from 1 gl / lOOg to 25 gl / lOOg, such as from 2 gl / lOOg to 25 gl / lOOg, such as from 3 gl / lOOg to 25 gl / lOOg, such as from 4 gl / lOOg to 25 gl / lOOg, such as from 5 gl / lOOg to 25 gl / lOOg, such as from 6 gl / lOOg to 25 gl / lOOg, such as from 7 gl / lOOg to 25 gl / lOOg, such as from 8 gl / lOOg to 25 gl / lOOg, such as from 9 gl / lOOg to 25 gl / lOOg, such as from 10 gl / lOOg to 25 gl / lOOg, such as from 15 gl / lOOg to 25 gl / lOOg, such as from 20 gl / lOOg to 25 gl / lOOg. In one aspect, the feed has a diene number of from 1 gl / lOOg to 20 gl / lOOg, such as from 1 gl / lOOg to 15 gl / lOOg, such as from 1 gl / lOOg to 10 gl / lOOg, such as from 1 gl / lOOg to 9 gl / lOOg, such as from 1 gl / lOOg to 8 gl / lOOg, such as from 1 gl / lOOg to 7 gl / lOOg, such as from 1 gl / lOOg to 6 gl / lOOg, such as from 1 gl / lOOg to 5 gl / lOOg, such as from 1 gl / lOOg to 4 gl / lOOg, such as from 1 gl / lOOg to 3 gl / lOOg, such as from 1 gl / lOOg to 2 gl / lOOg. In one aspect, the feed has a diene number of at least 1 gl / lOOg, such as at least 2 gl / lOOg, such as at least 3 g 1 / 100g, such as at least 4 gl / lOOg, such as at least 5 gl / lOOg, such as at least 6 gl / lOOg, such as at least 7 gl / lOOg, such as at least 8 gl / lOOg, such as at least 9 gl / lOOg, such as at least 10 gl / lOOg, such as at least 15 gl / lOOg, such as at least 20 gl / lOOg, such as at least 25 gl / lOOg. The diene number of the feed can be derived using the standard, ASTM UOP-326.

[0038] The feed is split into at least a first stream and a second stream. A fixed bed reactor is provided, which comprises at least a first reactor bed containing a first hydrotreatment catalyst and a second reactor bed containing a second hydrotreatment catalyst. The reactor beds are arranged in series, with the second catalyst bed being located downstream the first catalyst bed, such that gas exiting the first catalyst bed passes through the second catalyst bed.

[0039] The first stream is mixed with a recycle stream and a hydrogen-rich stream, and the mixed stream is fed to said first catalyst bed of the fixed bed reactor, whereby the polymerizable reactive compounds in the first stream are saturated in a catalytic saturation reaction. The miscibility of the first stream, the recycle stream and the hydrogen-rich stream is sufficiently high that ploymerization is hindered by dilution and lowering of diene values, while saturation in the catalytic saturation reaction is not hindered.

[0040] The second stream is fed to the second reactor bed of the fixed bed reactor, whereby the polymerizable reactive compounds in the second stream are saturated in a catalytic saturation reaction.

[0041] In one aspect, at least one of the first, second (and optional third) hydrotreatment catalysts are independently selected from the group comprising Mo, Ni, W, Pt, Pd, Cu, Fe, Zn and Ru- based catalysts and combinations thereof. In one aspect, the catalyst is in sulfided, partially sulfided (i.e., surface-passivated with sulfur) or reduced form.

[0042] In one aspect, the catalyst is a supported catalyst wherein the support is selected from alumina, silica, titania, magnesia and combinations thereof; optionally in combination with a molecular sieve having topology MFI, BEA or FAU. The combinations may be as physical mixtures or as oxide systems, such as silica-alumina, alumina-magnesia spinel and other spinel-group oxide systems.

[0043] In one aspect, the catalyst is Ni-based, Mo-based, CoMo-based, NiMo-based, W-based, NiW- based or Ru-based, optionally in sulfided or reduced form. In one aspect, the Ni-based catalyst comprises Ni in an amount of at least 90 wt% based on the Group 1 - 12 materials in the catalyst, such as at least 95 wt.% such as at least 99 wt.% such as 100 wt.%. In one aspect, the Mo-based catalyst comprises Mo in an amount of at least 90 wt% based on the Group 1 - 12 materials in the catalyst, such as at least 95 wt.% such as at least 99 wt.% such as 100 wt.%. In one aspect, the W-based catalyst comprises W in an amount of at least 90 wt% based on the Group 1 - 12 materials in the catalyst, such as at least 95 wt.% such as at least 99 wt.% such as 100 wt.%. In one aspect, the Ru-based catalyst comprises Ru in an amount of at least 90 wt% based on the Group 1 - 12 materials in the catalyst, such as at least 95 wt.% such as at least 99 wt.% such as 100 wt.%. In one aspect, the Ni-based catalyst comprises from 2-30 wt% Ni sulfided or reduced. In one aspect, the Mo-based catalyst comprises from 2-30 wt% Mo preferably sulfided. In one aspect, the CoMo-based catalyst comprises from 1-10 wt% Co and from 2-30 wt% Mo preferably sulfided. In one aspect, the NiMo-based catalyst comprises from 1-10 wt% Ni and from 2-30 wt% Mo preferably sulfided. In one aspect, the W-based catalyst comprises from 2-30 wt% W preferably sulfided. In one aspect, the NiW-based catalyst comprises from 1-10 wt% Ni and from 2-30 wt% W preferably sulfided. In one aspect, the Ru-based catalyst comprises from 0.1-10 wt% Ru preferably reduced.

[0044] In one aspect, the first and / or second hydrotreatment catalyst comprises Mo. In one aspect, the first and / or second hydrotreatment catalyst comprises Ni. In one aspect, the first and / or second hydrotreatment catalyst comprises W. In one aspect, the first and / or second hydrotreatment catalyst comprises Pt. In one aspect, first and / or second hydrotreatment catalyst comprises Pd. In one aspect, the first and / or second hydrotreatment catalyst comprises Cu. In one aspect, the first and / or second hydrotreatment catalyst comprises Fe. In one aspect, the first and / or second hydrotreatment catalyst comprises Zn. In one aspect, the first and / or second hydrotreatment catalyst comprises Ru.

[0045] In one aspect, the catalyst is sulphided. In one aspect, the hydrotreatment catalyst is a Ni- Mo based catalyst in sulfided form, i.e. NiMoS. The catalyst may be pre-sulfided by exposure to a sulfur containing stream or it may be sulfided in-situ i.e. during operation, for instance by sulfur present in the pyrolysis oil.

[0046] In a further aspect, at least one of the first, second (and optional third) hydrotreatment catalysts is a supported Ni-Mo based catalyst having a Ni content of 3-5 wt%, Mo content of 15-25 wt%, and optionally also a P content of 1-3 wt%, based on the total weight of the catalyst, such as wherein the support is selected from alumina, silica, titania, magnesia and combinations thereof; optionally in combination with a molecular sieve having topology MFI, BEA or FAU, optionally wherein the Ni-Mo based catalyst is in sulfided form, i.e. NiMoS.

[0047] The process of the present invention is suitably a continuous operation. The term continuous operation, as is well known in the art, means that the incoming stream of feed during a given production cycle is constant, as also is the stabilized liquid oil stream being withdrawn as the outcoming product. This is in contrast to a batch operation as is also well known in the art, in which the total amount of liquid oil and catalyst is introduced at the beginning of the process, and the outcoming product is withdrawn after a certain period of time.

[0048] The fixed bed reactor is adiabatic, and the hydrotreating reaction is exothermic. The first bed of the fixed bed reactor is typically at a temperature in the range 250-350°C. Subsequent beds are at temperatures between 20°C below and 30°C above the preceding bed. The temperature at start of run (SOR) would typically be 30°C-80°C lower than that at end of run (EOR).

[0049] In one aspect the feed is hydrotreated in the fixed bed reactor at a temperature of less than 400°C, such as less than 390°C, such as less than 380°C, such as less than 370°C, such as less than 360°C, such as less than 350°C, such as less than 340°C, such as less than 330°C, such as less than 320°C, such as less than 310°C, such as less than 300°C , such as less than 290°C, such as less than 280°C, such as less than 270°C, such as less than 260°C, such as less than 250°C, such as less than 240°C, such as less than 230°C, such as less than 220°C, such as less than 210°C, such as less than 200°C, such as less than 190°C, such as less than 180°C, such as less than 170°C, such as less than 160°C, such as less than 150°C, such as less than 140°C, such as less than 130°C, such as less than 120°C, such as less than 110°C, such as less than 100°C, such as less than 90°C, such as less than 80°C, such as less than 70°C.

[0050] In one aspect the feed is hydrotreated in the fixed bed reactor at a temperature of from 70 to 400°C, such as from 70 to 390°C, such as from 70 to 380°C, such as from 70 to 370°C, such as from 70 to 360°C, such as from 70 to 350°C, such as from 70 to 340°C, such as from 70 to 330°C, such as from 70 to 320°C, such as from 70 to 310°C, such as from 70 to 300°C, such as from 70 to 290°C, such as from 70 to 280°C, such as from 70 to 270°C, such as from 70 to 260°C, such as from 70 to 250°C, such as from 70 to 240°C, such as from 70 to 230°C, such as from 70 to 220°C, such as from 70 to 210°C, such as from 70 to 200°C, such as from 70 to 190°C, such as from 70 to 180°C, such as from 70 to 170°C, such as from 70 to 160°C, such as from 70 to 150°C, such as from 70 to 140°C, such as from 70 to 130°C, such as from 70 to 120°C, such as from 70 to 110°C, such as from 70 to 100°C, such as from 70 to 90°C, such as from 70 to 80°C.

[0051] In one aspect, the feed is hydrotreated in the fixed bed reactor at a temperature in the range 70-250°C, such as in the range 80-200°C. In one aspect, the feed is hydrotreated in the fixed bed reactor at a temperature in the range 250-400°C.

[0052] In one aspect, the temperature is in the range 250-400°C; the pressure is 20-175 barg; and the LHSV is 0.5-8 h-1, and the H2-to-oil ratio is from 50 to 2000 Nm3 / m3, such as at least 200 Nm3 / m3and less than 1000 Nm3 / m3or less than 600 Nm3 / m3. The H2to oil ratio may conveniently also be determined relative to the theoretical hydrogen consumption, which is the amount of hydrogen required to replace all heteroatoms and to saturate all carboncarbon bonds in the feed. Commonly this theoretical hydrogen consumption is multiplied by a safety factor which commonly may be at least 2 or 3 and less than 5, 8 or 10. The cost effectiveness of such an excess of hydrogen is enabled by recycling the hydrogen as a recycle gas after separation of liquid product and optionally purification of the recycle gas.

[0053] In one aspect, the fixed bed reactor comprises a mixer between the first reactor bed and the second reactor bed. In one aspect, the mixer is a quench mixer, supporting mixing of added quench hydrogen and the liquid. The quench system installed between the beds ensures proper mixing of the second reactor bed feed and effluent from the first reactor bed, thus avoiding flow maldistribution in the second reactor bed.

[0054] In one aspect, the volume ratio of the first reactor bed to the second reactor bed is from 20:80 to 80:20. In one aspect, the volume ratio of the first reactor bed to the second reactor bed is from 20:80 to 75 :25. In one aspect, the volume ratio of the first reactor bed to the second reactor bed is from 20:80 to 70:30. In one aspect, the volume ratio of the first reactor bed to the second reactor bed is from 20:80 to 65:35. In one aspect, the volume ratio of the first reactor bed to the second reactor bed is from 20:80 to 60:40. In one aspect, the volume ratio of the first reactor bed to the second reactor bed is from 20:80 to 55:45. In one aspect, the volume ratio of the first reactor bed to the second reactor bed is from 20:80 to 50:50.

[0055] The fixed bed reactor may further comprise a third reactor bed containing a third hydrotreatment catalyst, wherein said third catalyst bed is located downstream the second catalyst bed, such that gas exiting the second catalyst bed passes through the third catalyst bed, the process comprising further the steps of: splitting said first feed into at least a first stream, a second stream and a third stream, feeding the third stream to the third reactor bed of the fixed bed reactor, whereby the polyunsaturated hydrocarbons in the third stream are saturated in a catalytic saturation reaction.

[0056] Suitably, the feed is not subjected to a diolefin removal step, upstream the fixed bed reactor. Also, the process plant configured to carry out the process of the invention can suitably avoid a diolefin reactor. Therefore, there are no hydrotreating steps which take place below 250°C. Accordingly, ammonium halide salts are not formed, and cannot solidify in the process or plant.

[0057] According to this aspect, the fixed bed reactor may comprise a mixer, such as a quench mixer, between the second reactor bed and the third reactor bed. A first hydrocarbon stream is outputted from the fixed bed reactor. The first hydrocarbon stream has a lower concentration of polymerizable reactive compounds than the feed.

[0058] The first hydrocarbon stream is fed to a charge heater and heated to provide a second hydrocarbon stream. Subsequently, the second hydrocarbon stream is fed to a hydrotreatment reactor and subjected to a catalytic hydrotreament step, so as to provide a third hydrocarbon stream from the hydrotreatment reactor.

[0059] The hydrotreatment (HDT) step is commonly operated in a separate reactor at higher temperature. Thereby, any organic heteroatoms like nitrogen, sulfur, oxygen, chlorine, bromine and fluorine present in the second hydrocarbon stream are removed and a third hydrocarbon stream (hydrotreated stream) is produced. The third hydrocarbon stream will have almost zero content diene, sulfur <5 wt ppm, chlorine <5 wt ppm, nitrogen <5 wt ppm, and olefin <0.5 wt%, and notably the level of conjugated di-olefins and other reactive molecules is reduced to levels sufficiently low to avoid problematic polymerization.

[0060] The third hydrocarbon stream is fed to a hot separator where it is separated into at least a gaseous fraction and a liquid fraction. At least a portion of the liquid fraction is used as at least a portion of the recycle stream. In a further aspect, the hydrogen-rich stream (to be mixed with the first stream) is produced by upgrading at least a portion of the gaseous fraction from the hot separator.

[0061] The step of upgrading the gaseous fraction from the hot separator may comprise subjecting the gaseous fraction to one or more steps of: a. a water wash b. High Pressure Cold Separator (HPCS) c. addition of make-up gas to said gaseous fraction.

[0062] The process of the present invention may comprise one or more further steps. These one or more further steps may be before, after, or intermediate to the steps recited herein.

[0063] The third hydrocarbon stream (hydrotreated stream) can be further treated for producing hydrocarbon products boiling in the transportation fuel range, such as diesel, jet fuel and naphtha. The further treatment may include any of: hydrodewaxing or isomerization, as is well known in the art of fossil oil refining. Other types of hydrotreating are also envisaged, for instance hydrodearomatization (HDA). The material catalytically active in hydrodearomatization 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, magnesia or titania, or combinations thereof).

[0064] A process plant configured for carrying out the process according to the invention is also provided.

[0065] Figures 1 and 2 contain the following components:

[0066] (PPO) feed (1) first stream (1A) second stream (IB), third stream (1C), fixed bed reactor (10) a first reactor bed (10A) a second reactor bed (10B) recycle stream (9) hydrogen-rich stream (8), mixed stream (5) first hydrocarbon stream (11) from the fixed bed reactor (10) charge heater (20) second hydrocarbon stream (21) hydrotreatment reactor (30) third hydrocarbon stream (31) from the hydrotreatment reactor (30) hot separator (40) gaseous fraction (41) liquid fraction (42)

[0067] Hot liquid stream to stripper (42A) from hot separator (40) heat exchanger (15) - shell side upstream the hydrotreatment reactor 30 and tube side downstream said hydrotreatment reactor 30

[0068] Fixed bed reactor combined feed I Hydrotreatment reactor effluent exchanger (35)

[0069] Hydrotreatment reactor effluent steam generator (45)

[0070] 5 - boiler feed water

[0071] 46 - Steam export a water wash (50) with feed water (43)

[0072] High Pressure Cold Separator (HPCS) (60)

[0073] High pressure cold separator vapor (61)

[0074] High pressure cold separator boot water (62)

[0075] Cold liquid stream to stripper from high pressure cold separator (63)

[0076] Recycle gas compressor suction drum (70)

[0077] Recycle gas compressor suction drum vapor (recycle gas) (71) make-up gas (44) to said gaseous fraction (41).

[0078] The invention will now be described with reference to the following non-limiting examples. EXAMPLE

[0079] In the following :

[0080] 1) The feed can have diene value of 2 gI / 100 g to 10 gI / 100 g, sulfur 100 to 1000 wt ppm, chlorine 50 to 1500 wt ppm, nitrogen 100 to 4000 wt ppm, olefins 40 to 80 wt%

[0081] 2) The product will have diene almost nil, sulfur <5 wt ppm, chlorine <5 wt ppm, nitrogen <5 wt ppm, olefin <0.5 wt%

[0082] 3) The operating pressure can be from 30 to 120 barg

[0083] 4) LHSV can be from 0.1 to 2 hr1

[0084] 5) Gas to oil ratio based of reactor charge shall be ~200 to 600 Nm3 / m3 for the Guard & hydrotreating reactor.

[0085] 6) Typical catalyst is TK-341 / 347 & 359

[0086] A feed with the above characteristics is directed to the process as illustrated in Figure 2.

[0087] With no feed split, and a ratio of recycle stream to feed of 1.5: 1, the diene number in the first bed would be ca. 2.00 gI / 100 g unless a stabilization reactor is used. The temperature at the outlet of the third bed, in this case, is 343°C. This would be related to potential polymerization of feedstock, causing a shorter catalyst lifetime. The table below shows the diene values assuming an upstream stabilization reactor. Alternatively, bed 1 would receive a feed with a diene value of 2.0 gI / 100 g, which likely would result in polymerization in parallel with complete hydrogenation of the dienes.

[0088] With a 33:33:33 split of the feed into first, second and third streams, ratio of recycle stream to feed of 1.5: 1, the diene number in the first bed falls to ca. 0.90 gI / 100 g. In this example, the temperature is maintained below 326°C, and the concentration of reactive compounds is kept sufficiently low, such that polymerization is avoided. In this scenario the entire recycle oil is mixed with 33% of feed in each bed helping reduce the diene number to <1 No Split With Split

[0089] Temperature Diene Temperature Diene

[0090] [°C] [gl / 100 g] [°C] [gl / 1OO g]

[0091] Bed 1 IN 290 <0.1 305 0.9

[0092] Bed 1 OUT 329 <0.1 326 <0.1

[0093] Bed 2 IN 329 <0.1 297 0.8

[0094] Bed 2 OUT 337 <0.1 315 <0.1

[0095] Bed 3 IN 337 <0.1 291 0.7

[0096] Bed 3 OUT 343 <0.1 306 <0.1

[0097] Various modifications and variations of the present invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in chemistry or related fields are intended to be within the scope of the following claims.

Claims

CLAIMS1. A process for hydroprocessing a feed which is the result of pyrolysis of a solid material, said process comprising the steps of: providing a feed (1), comprising hydrocarbons, hydrocarbonaceous compounds and at least one polymerizable reactive compound, splitting said feed (1) into at least a first stream (1A) and a second stream (IB), providing a fixed bed reactor (10) comprising at least a first reactor bed (10A) containing a first hydrotreatment catalyst and a second reactor bed (10B) containing a second hydrotreatment catalyst, mixing the first stream (1A) with a recycle stream (9) and a hydrogen-rich stream (8), and feeding the mixed stream (5) to said first catalyst bed (10A) of the fixed bed reactor (10), whereby the polymerizable reactive compounds in the first stream (1A) are saturated in a catalytic saturation reaction, feeding the second stream (IB) to the second reactor bed (10B) of the fixed bed reactor (10), whereby the polymerizable reactive compounds in the second stream (IB) are saturated in a catalytic saturation reaction, wherein said second catalyst bed (10B) is located downstream the first catalyst bed (10A), outputting a first hydrocarbon stream (11) from the fixed bed reactor (10), said first hydrocarbon stream (11) having a lower concentration of polymerizable reactive compounds than the feed (1), feeding the first hydrocarbon stream (11) to a charge heater (20) and heating it to provide a second hydrocarbon stream (21), feeding the second hydrocarbon stream (21) to a hydrotreatment reactor (30) and subjecting it to a catalytic hydrotreament step, so as to provide a third hydrocarbon stream (31) from the hydrotreatment reactor (30), feeding the third hydrocarbon stream (31) to a hot separator (40) where it is separated into at least a gaseous fraction (41) and a liquid fraction (42), wherein at least a portion of the liquid fraction (42) is used as at least a portion of the recycle stream (9) and wherein at least a portion of said hydrogen-rich stream (8) is provided by upgrading the gaseous fraction (41) from the hot separator (40) and wherein hydrogen is present in excess of the theoretical hydrogen consumption.

2. The process according to claim 1, wherein the feed (1) comprises at least one polymerizable reactive compound selected from polyunsaturated hydrocarbons, sugars, carbonyls, styrene homologues, vinyl-aromatics and other polymerisable reactive compoundsfrom biological pyrolysis oil, preferably polyunsaturated hydrocarbons, such as conjugated dienes or vinyl-aromatics.

3. The process according to claim 1 or 2, wherein the feed (1) comprises at hydrocarbonaceous compounds, to an extent least one polymerizable reactive compound selected from polyunsaturated hydrocarbons, sugars, carbonyls, styrene homologues, vinyl- aromatics and other polymerisable reactive compounds from biological pyrolysis oil, preferably polyunsaturated hydrocarbons, such as conjugated dienes or vinyl-aromatics.

4. The process according to claim 3, wherein upgrading the gaseous fraction (41) from the hot separator (40) comprises subjecting the gaseous fraction (41) to one or more steps of: a. a water wash (50) b. separation in a High Pressure Cold Separator (HPCS) (60), c. addition of make-up gas (44) to said gaseous fraction (41).

5. The process according to any one of the preceding claims, wherein the volume ratio of the first reactor bed to the second reactor bed is from 20:80 to 80 :20, such as wherein the volume ratio of the first reactor bed to the second reactor bed is from 20:80 to 50 :50, such as wherein the volume ratio of the first reactor bed to the second reactor bed is from 20 :80 to 40:60.

6. The process according to any one of the preceding claims, wherein the volume ratio of the first stream (1A) to the second stream (IB) is from 20:80 to 80 :20, such as wherein the first stream (1A) to the second stream (IB) is from 20:80 to 50:50, such as wherein the first stream (1A) to the second stream (IB) is from 20:80 to 40:60.

7. The process according to any one of the preceding claims, wherein the fixed bed reactor further comprises a third reactor bed (10C) containing a third hydrotreatment catalyst, wherein said third catalyst bed (10C) is located downstream the second catalyst bed (10B), such that gas exiting the second catalyst bed (10B) passes through the third catalyst bed (10C), the process comprising further the steps of: splitting said first feed (1) into at least a first stream (1A), a second stream (IB) and a third stream (1C),feeding the third stream (1C) to the third reactor bed (10C) of the fixed bed reactor (10), whereby the polyunsaturated hydrocarbons in the third stream (1C) are saturated in a catalytic saturation reaction.

8. The process according to claim 7 wherein the fixed bed reactor comprises a mixer, such as a quench mixer, between the second reactor bed and the third reactor bed.

9. The process according to any one of the preceding claims wherein at least one of the first, second and third hydrotreatment catalysts are independently selected from the group comprising Mo, Ni, W, Pt, Pd, Cu, Fe, Zn and Ru-based catalysts and combinations thereof.

10. The process according to claim 9 wherein at least one of the first, second and third hydrotreatment catalysts is a supported Ni-Mo based catalyst having a Ni content of 3-5 wt%, Mo content of 15-25 wt%, and optionally also a P content of 1-3 wt%, based on the total weight of the catalyst, such as wherein the support is selected from alumina, silica, titania, magnesia and combinations thereof; optionally in combination with a molecular sieve having topology MFI, BEA or FAU, optionally wherein the Ni-Mo based catalyst is in sulfided form, i.e. NiMoS.

11. The process according to any one of the preceding claims, wherein the feed is not subjected to a diolefin removal step, upstream the fixed bed reactor (10).

12. The process according to any one of the preceding claims, wherein the ratio of hydrogen is kept above the theoretical required amount by at least a factor of 2 or 3 and less than a factor of 5, 8 or 10.

13. A process plant configured for carrying out the process according to any one of claims 1 to 11.

Images