Stabilization and hydrotreatment of reactive feedstock with separate gas loops

Abstract

The present application relates to the production of hydrocarbons and hydrocarbonaceous compounds from reactive feedstock by hydrotreatment in two zones, and a cost-effective way of avoiding corrosion by design of the process with a separate gas loop for each hydrotreatment zone.

Description

DescriptionTitle of Invention:Stabilization and hydrotreatment of reactive feedstock with separate gas loopsTechnical Field

[0001] The present application relates to the production of hydrocarbons and hydrocarbonaceous compounds from reactive feedstock by hydrotreatment in two zones, and specifically to a cost-effective way of avoiding corrosion by design of the process gas loop.Background Art

[0002] A higher demand is expected for the hydroprocessing of advanced renewable feedstocks, such as pyrolysis oils derived from solid renewable feedstocks or from waste plastic. Such feedstocks will have a high oxygen content, as well as other heteroatoms, such as nitrogen and halides, which needs to be decreased before it can be used as liquid fuel, i.e. as hydrocarbon fuel boiling in the transportation fuel range. The bulk amount of oxygen is generally removed by hydroprocessing in a catalytic hydrodeoxygenation (HDO) using high pressure (10-20 MPag) and high temperature (350-400°C). However, the pyrolysis oil may be very reactive, either having a content of reactive oxygenates or - especially in the case of waste plastic pyrolysis oil - of conjugated diolefins. Such a pyrolysis oil may be very unstable and with a tendency to polymerize at moderately elevated temperature, which leads to rapid catalyst deactivation and plugging of the HDO reactor, due to coking. Therefore, it is desired to stabilize pyrolysis oils thereby i.a. by converting carbonyls to alcohols at temperatures from 80°C to 250°C. During the processing of such feedstock, ammonia and halides such as chloride, bromide and fluoride may be released by hydroprocessing, and if both compounds are present at moderate temperatures, ammonium halide may precipitate, causing a risk of corrosion, which must be reduced by use of corrosion resistant steel qualities.

[0003] A significant cost in such hydroprocessing is the consumption of hydrogen, especially considering that to minimize the risk of coking throughout the reactorsystem, the estimated consumption of hydrogen is commonly multiplied with a safety factor of three to ten. To minimize this cost, hydrogen is recycled in a so- called gas loop by separating a gas phase and optionally purifying it.

[0004] The operation of a gas loop is commonly handled by a gas / liquid separator and a compressor directing the gas from the low-pressure product output to the high pressure feedstock inlet. When operating a process with combination of a sulfided base metal catalyst, requiring presence of sulfur, and noble metal catalyst, requiring highly pure hydrogen, hydrogen may be recycled in two gas loops, with a purge from the noble metal gas loop to the base metal gas loop, and the same may also be the case for processes where it is beneficial to operate two steps at different pressures, but such processes involving two gas loops will involve additional cost of equipment as well as added cost of operation, and are thus avoided unless a specific reason is present to justify the added cost.Technical Problem

[0005] We have identified that a process releasing even very minor amounts of chloride and other halides and ammonia to the gas phase, and operating at low temperatures, has a risk of precipitating corrosive ammonia in the process equipment, causing a need for expensive corrosion resistant materials.Summary of Invention

[0006] Two gas loops are introduced as the cost of corrosion resistant materials even in part of the equipment in a process plant may be higher than the cost of providing and operating a process plant with two gas loops.Solution to Problem

[0007] By having a first gas loop for stabilization reactions releasing chloride and possibly other halides, but no ammonia, at low temperatures and a second gas loop, receiving a purge from the first gas loop, for hydrotreatment releasing nitrogen as ammonia at elevated temperatures, the combined presence of ammonia and chloride is only found where the temperature is safely above precipitation temperatures, and therefore the risk of precipitation is avoided.Definitions

[0008] In the following a hydrocarbonaceous mixture shall be used to signify a feedstock rich in molecules comprising hydrogen and carbon, but also heteroatoms, i.e. other elements, such as oxygen, sulfur and nitrogen.

[0009] In the following a hydrocarbon mixture shall be used to signify a feedstock dominated by molecules comprising hydrogen and carbon, but possibly also comprising heteroatoms.

[0010] For the purpose of the present application, the unit wt% shall designate weight / weight % and the unit molar% shall designate molar / molar%.

[0011] For the purpose of the present application, where concentrations in the gas phase are given, they are, unless otherwise specified, given as molar / molar concentration, under the assumption that no gaseous compounds are dissolved in the liquid phase for two-phase flows.

[0012] For the purpose of the present application, where elemental concentrations are given, they are, unless otherwise specified, given as weight / weight concentrations.

[0013] Where concentrations of oxygenates or other groups of molecules are referred to they shall signify the concentration of all the molecules of such a group, and not to the functional group.

[0014] The unit “MPag”, shall in compliance with the practice of the field be used to denote MPa, gauge, i.e. the pressure relative to atmospheric pressure.

[0015] A material catalytically active in a chemical reaction such as hydrodeoxygenation or hydrocracking shall be understood as a material having significant catalytic activity and preference for said chemical reaction under the conditions used. As it will be realized by the skilled person, most reactions will show an amount of side reactions, but unless otherwise specified the term a material catalytically active in a chemical reaction shall be understood as a combination of feedstock composition and physical conditions under which a commercially relevant amount of conversion takes place with higher selectivity than any other chemical reaction.Detailed description

[0016] Thermal decomposition of solid materials or suspensions of solid materials to liquid hydrocarbonaceous mixtures and subsequent hydrotreatment of hydrocarbonaceous mixtures to fuels is a way to provide liquid fuels from biological sources and / or waste sources.

[0017] Thermal decomposition shall for convenience be used broadly for any 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 sub- stoichiometric 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. The term shall be construed to include processes known as pyrolysis and hydrothermal liquefaction, both in the presence and absence of a catalyst.

[0018] In one aspect, the thermal decomposition is hydrothermal liquefaction. Hydrothermal liquefaction means the thermochemical conversion of biomass into liquid fuels by processing in a hot, pressurized water environment for sufficient time to break down the solid bio-polymeric structure to mainly liquid components. Typical hydrothermal processing conditions are temperatures in the range of 250- 425°C and operating pressures in the range of 40-350 bar. This technology offers the advantage of operation at a lower temperature, higher energy efficiency and lower tar yield compared to pyrolysis, e.g. fast pyrolysis. Equivalent solvolysis methods exist in which solvents other than water are used.

[0019] In one aspect, the thermal decomposition further comprises passing said solid renewable feedstock through a solid renewable feedstock preparation section comprising for instance drying for removing water and / or comminution for reduction of particle size, especially for processes other than hydrothermal liquefaction, which actively employs water. Any water / moisture in the solid renewable feedstock which vaporizes in for instance the thermal decomposition section condenses in the pyrolysis oil stream and is thereby carried out in the downstream process, which may be undesirable. Furthermore, the heat used for the vaporization of water withdraws heat which otherwise is necessary for the pyrolysis. By removing water and providing a smaller particle size in the solid renewable feedstock, the thermal efficiency of the pyrolysis section is increased.

[0020] For the product of thermal decomposition, for simplicity pyrolysis oil, the physical properties such as boiling point and freezing point of the pyrolysis oil may be satisfactory, but removal of impurities and heteroatoms may be the only requirement, which may be carried out by hydrotreatment - the addition of hydrogen without intended breaking of carbon-carbon bonds, such as saturation of olefins as well as removal of heteroatoms such as sulfur, oxygen, nitrogen, metals, chloride and other halogens. Such hydrotreatment may beneficially be carried out with the dilution by compatible feedstocks, such as liquid hydrocarbonaceous streams of fossil or biological origin.

[0021] In the present context, the term pyrolysis oil shall not be construed as limited to specific thermal decomposition methods but shall merely be considered a convenient term for liquids originating from any conversion of solid or semi-solid materials, including plastic waste, municipal waste, biological waste, manure and sewage sludge. The thermal decomposition step may be carried out in a separate location and a commercial entity separate from the process plant carrying out hydroprocessing, and the transfer of oil between entities and sites may involve tank transport by truck, ship or other means.

[0022] Commonly reactive hydrocarbonaceous feedstock derived from a thermochemical decomposition of a solid renewable material, comprises 40-85 wt% C and 3-50 wt% O and an atomic ratio between H and C of less than 1.8 or 1 .6, and commonly with elevated presence of reactive compounds such as phenols, furans, polyunsaturated hydrocarbons, sugars, carbonyls, styrene homologues, vinyl-aromatics and other polymerisable reactive compounds from biological pyrolysis oil. The composition of products from thermal decomposition of artificial polymers may involve 0.5-5 wt% or 0.5-10 wt% of conjugated diolefins 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%. In addition specific heteroatoms may be present, highly dependent on the source of feedstock and the thermochemical process.

[0023] Whether a feedstock is considered reactive may be evaluated by passive heating to 80°C, in a closed container, without stirring or provision of gas for 24 hr. If the viscosity as evaluated at 40°C according to ASTM D 7042 before and afterthe test, shows an increase by more than 5% the feedstock is considered reactive.

[0024] The stabilization hydrotreatment may be carried out at slightly elevated temperatures such as from above 80°C or 150°C to below 200°C or 250°C, and if organically bound halides are present, then depending on the nature of the halide compounds in the feedstock some or all may be released at these conditions. This means that the low temperature stabilization is likely to release some halide to the gas phase, in the form of hydrogen halides, which in the gas phase is only mildly corrosive.

[0025] Contrary to halide-heteroatoms, nitrogen heteroatoms are not very reactive. This means that at temperatures below 250°C nitrogen will not be released as ammonia, and therefore the gas phase from the low temperature reactions will be absent of ammonia, and thus ammonium halides may not form and precipitate.

[0026] At temperatures above 250°C or 300°C organically bound nitrogen may be released as ammonia under hydrotreatment conditions. However, even if both halides and ammonia are present at these temperatures, precipitation of ammonium halide will not occur, due to the temperature.

[0027] The material catalytically active in hydrotreatment, typically comprises one or more active metals (commonly sulfided base metals such as nickel, cobalt, tungsten and / or molybdenum, but if the hydrocarbon is free of sulfur and nitrogen compounds possibly the alternative of reduced base metals such as nickel, copper, molybdenum, cobalt and / or tungsten as well as reduced noble metals such as ruthenium, rhodium, platinum and / or palladium and other metals of the platinum group) and a refractory support (such as alumina, silica or titania, or combinations thereof). Base metal catalysts are commonly tungsten and / or molybdenum promoted by presence of nickel and / or cobalt (2-20 wt% molybdenum and / or tungsten in combination with nickel and / or cobalt in an atomic ratio of 0.2-1 .0 (Ni+Co):(Mo+W)), and commonly the support is a simple refractive material such as alumina, silica, titania or activated carbon. Commonly the material is absent of more acidic materials such as molecular sieves and amorphous silica-alumina, but not necessarily. In general all hydrotreatment catalysts are active in all hydrotreatment reactions, although with some variationin activity, but for hydrodeoxygenation of compositions comprising carboxylic acids and other reactive carbonyl groups a molybdenum based catalyst with much lower concentration of promoter (such as atomic ratios below 0.1 ), or even absence of promoters, may however be favorably used as such a material will favor selectivity toward hydrodeoxygenation, separating oxygen as water, over decarboxylation / decarbonylation separating oxygen as carbon oxides in feedstocks with carbonyl groups or carboxylic acids, thus avoiding a loss of biological carbon. In addition, the lower catalyst activity may slow down the reaction rate and thus distribute heat released by the exothermic reactions.

[0028] Active hydrotreating conditions typically involve a temperature in the interval 250-460°C, a pressure in the interval 3-30 MPa, and a liquid hourly space velocity (LHSV) in the interval 0.1-5 hr1and a GOR (gas to oil ratio) of 300-10000 Nm3 / m3optionally together with intermediate cooling by quenching with cold hydrogen, feed or product. The GOR would depend on the theoretical hydrogen consumption for hydrotreating the feedstock, multiplied by a safety factor which commonly may be at least 2 or 3 and less than 5, 8 or 10. For reactive compounds, such as olefins and reactive oxygenates, hydrotreatment may take place at temperatures above 80°C, 100°C or 120°C and less than 150°C, 200°C or 250°C, and to control side reactions; such as polymerization or thermal overheating, it may be necessary to conduct stabilization hydrotreatment at such very mild conditions, to reduce reactivity and stabilize the reactive compounds. The seventy of hydrotreatment is typically increased by increasing temperature, hydrogen availability (partial pressure and relative flow rate) and the metal content and dispersion on catalysts. The estimation of the required severity to activate hydrotreatment for different compounds and conditions is a well known task to the skilled person, and will be based on a combination of literature study and experimental work.

[0029] In practice multiple catalytically active materials may be used in sequence, e.g. with an unpromoted catalytically active material comprising molybdenum and less than 0.5 wt% nickel and cobalt on a refractory support, commonly followed by a promoted catalytically active material comprising molybdenum or tungsten in combination with nickel or cobalt on a refractory support to support the reaction going to completion.

[0030] When the heteroatom ic products of hydrotreatment are fluid, such as hydrocarbons and products comprising heteroatoms (such as water, ammonia, hydrochloric acid and hydrogen sulfide) these will leave the reactor and may be separated downstream. When the heteroatom ic products are solid (such as from released metals, silicon and phosphorous), they will commonly precipitate on the catalytically active material, which therefore preferably is designed to have a capacity for uptake of such solid heteroatomic compounds, e.g. by high void space, high surface areas and high pore diameters. Catalytically active material for such intended precipitation is commonly known as guard materials.

[0031] The molecular structure of pyrolysis oils may also be modified by hydroconversion, in which the structure of molecules is altered, either by hydrocracking in which carbon-carbon bonds are broken, with the addition of hydrogen, such that the size of molecules is reduced, or rings are opened or by isomerization, in which the structure of molecules is altered, maintaining the same molecular sum formula.

[0032] The material catalytically active in hydroconversion typically comprises an active metal (either elemental noble metals such as platinum and / or palladium or sulfided base metals such as nickel, cobalt, tungsten and / or molybdenum ), an acidic support (for hydrocracking typically a molecular sieve showing high cracking activity, and having a topology such as MFI, BEA and FAU or amorphous silica-alumina or a combination of such materials and for isomerization typically a molecular sieve showing high shape selectivity, and having a topology such as MOR, FER, MRE, MWW, MTW, AEL, TON and MTT) and a refractory support (such as alumina, silica or titania, or combinations thereof). Materials catalytically active in hydrocracking and isomerization are similar, but commonly for isomerization the acidic support is of a different structure supporting only specific molecular re-configuration possibly in combination with a lower acidity e.g. due to silica:alumina ratio, making reactions slower, which often favors specificity.

[0033] Active hydroconversion conditions using sulfided catalysts typically involve a temperature in the interval 300-460°C, but the upper limit for moderate severity hydrocracking would often be 425°C or 400°C, a pressure in the interval from 3 MPag to15 MPag, 20 MPag or 30 MPag, a liquid hourly space velocity (LHSV) inthe interval 0.1 -10 hr1, commonly 0.5 hr1to 8 hr1, and a gas to oil ratio (GOR) of 300-5000 Nm3 / m3, optionally together with intermediate cooling by quenching with cold hydrogen, feed or product. The GOR would depend on the conversion and the theoretical hydrogen consumption of the hydrocracking reactions consuming hydrogen, multiplied by a safety factor, which commonly may be at least 2 or 3 and less than 6, 8 or 10. Hydroconversion conditions using elemental noble metal catalysts typically involve a lower temperature in the interval 230- 315°C, but otherwise similar conditions. Hydroconversion severity is typically increased by increasing temperature, reduced space velocity, hydrogen availability (partial pressure and relative flow rate), the metal content and dispersion and the acidity of molecular sieve and acidic supports on catalysts. As known to the skilled person the hydrocracking seventy may be changed to optimize the process with respect to product composition and boiling point, in response to demands from product mix or feedstock characteristics. The choice of catalyst activity may be made to support the desired flexibility in severity.

[0034] As mentioned above hydroprocessing catalysts may comprise reduced metals or sulfided base metals. Noble metals (one or both of platinum and palladium - and possibly other metals of the platinum group - IIIPAC Groups 8, 9 and 10, periods 5 and 6) are active in the elemental form and active in low amounts, such as 0.05 wt% to 2 wt%. The noble metals are sensitive to the presence of especially sulfur and nitrogen, which may reduce the activity dramatically, and must therefore operate in the presence of less than 50 ppmwt sulfur and nitrogen, which is called sweet mode. Other reduced metals, including nickel, copper, molybdenum, cobalt and tungsten, may also be used in sweet mode environments. Contrary to this, base metals (commonly molybdenum and tungsten, which may be promoted by presence of nickel and cobalt) are active in their sulfided form, requires higher metal concentrations (2-20 wt% molybdenum and / or tungsten in combination with nickel and / or cobalt in an atomic ratio of 0.2- 1 .0 (Ni+Co):(Mo+W)), and thus very robust in the presence of such heteroatoms (called sour gases) and actually must operate in the presence of more than 50- 200 ppmwt sulfur, which is called sour mode. In addition, the acidity of the support of hydrocracking and isomerization catalysts may be reduced by ammonia, being a product of hydrotreatment of hydrocarbons comprising nitrogen, which atmoderate levels such as 50 ppb to 50 ppm may be employed to control the selectivity towards middle distillates. At elevated levels a presence of ammonia may be undesired as it will deactivate the cracking and isomerization activity.

[0035] If noble metals are used for hydroconversion and sulfided base metals are used for hydrotreatment, the hydroconversion step will have it’s own gas loop, to avoid a conflict between the required presence of sulfur in hydrotreatment and the required absence in hydroconversion.

[0036] If the high temperature reaction off-gas is recycled to the low temperature stabilization section, precipitation becomes a potential issue, and therefore equipment operating below precipitation temperatures such as below 200°C must be provided in corrosion resistant materials. The precipitation temperature may be estimated from thermodynamics, based on concentrations of ammonium, halides and pressure. Two illustrative examples of precipitation temperatures would be 150°C for 0.78 pprrimoiar NH3, 2.7 pprrimoiar HCI at 18 MPag, and be 120°C for 0.03 pprrimoiar NH3, 1.7 pprrimoiar HCI at 17.5 MPag. Precipitation is especially concerning in relation to two-phase flow and narrow equipment. In open gas lines, moderate formation of particulate may be acceptable, as it will not precipitate permanently. For simplicity, and implicitly adding a safety factor, the estimation of precipitation temperature is made under the assumption that no gaseous compounds are dissolved in the liquid phase for two-phase flows.

[0037] If a common gas loop recycles hydrogen rich gas comprising even small amounts of ammonia to the stabilization section where small amounts of halides are released, a risk of precipitation exists, which poses a two-fold risk; corrosion and blockages. Corrosion of high-pressure equipment, containing hydrogen and other combustible materials is a safety risk, which may be avoided by cladding with materials, such as Alloy 625. However, such corrosion-resistant materials are significantly more expensive than carbon steel usually employed, especially for complex equipment such as heat exchangers.

[0038] The possibility of cleaning the recycled gas by capturing ammonia by water wash was also investigated, but after water wash, it was estimated that 0.02 pprrimoiar ammonia may remain which is sufficient to cause a risk of precipitation.

[0039] If, alternatively, two gas loops are employed; one ammonia free for the low temperature section and another for the high temperature section of the process, precipitation of corrosive ammonium chloride is avoided, as low temperature and presence of ammonia as well halides do not occur simultaneously.

[0040] While hydrogen rich gas is recycled, provision of make-up hydrogen is required to ensure sufficient presence of hydrogen for the reactions. Similarly, a purge of contaminated gas is taken out to avoid concentration of off-gases. When several gas loops are used, it is common to provide make-up gas in the loop requiring the highest purity, and directing the purge to less sensitive gas loops, but make-up gas may also be provided to several gas loops.

[0041] For the configuration of concern, make-up gas is added to the low temperature stabilization gas loop, and the low temperature stabilization gas loop purge is directed to the high temperature hydrotreatment gas loop. If a separate noble metal hydroconversion gas loop was present, this loop could be considered the high purity loop receiving make-up gas, directing purge to the stabilization gas loop and directing purge from that loop to the high temperature hydrotreatment gas loop. However, as ammonia is commonly used to moderate the activity of hydroconversion catalysts, it may also be chosen to add make-up gas to the low temperature stabilization gas loop upstream the hydroconversion gas loop. If hydroconversion was made in the presence of catalytically active material comprising sulfided base metals, the preferred gas loop configuration would involve a common gas loop for high temperature hydrotreatment and hydroconversion.

[0042] We have identified that such a concept will enable operation in the low temperature stabilization gas loop with a gas phase concentration of more than 1 pprrivoi hydrogen halides, when the stabilization section gas is substantially absent of ammonia. If a feedstock is processed, in which organic nitrogen is more reactive that organic halide (such as for feedstocks rich in unreactive PFAS compounds), a similar concept may also be implemented, in which the stabilization section gas is kept absent of hydrogen halides. As an example, the concentration of NH3 may be kept below 1 ppbvoi, 5 ppbvoior 10 ppbvoi- This may be achieved by having separate gas loops and recycle compressors, incombination with selection of conditions and catalysts avoiding simultaneous release of hydrogen halides and ammonia at low temperature.Advantageous Effects of Invention

[0043] A first embodiment, relates to a process for conversion of a reactive comprising at least 0.5 ppmwt halides and at least 5 ppmwt nitrogen hydrocarbonaceous mixture to a hydrocarbon product comprising the steps in a stabilization section a. directing a two-phase feed to a stabilization zone containing a material catalytically active in stabilization hydrotreatment under stabilization conditions, said two phase feed comprising a liquid phase comprising said reactive hydrocarbonaceous mixture and a first gaseous phase comprising an amount of make-up hydrogen gas b. withdrawing a two-phase stabilized product from said stabilization zone and separating said two-phase stabilized product into a stabilization section gas and a stabilized hydrocarbonaceous product and comprising the steps in a high temperature section operating at a temperature above the temperature of the stabilization section c. directing a two-phase stabilized feed stream to a hydrotreatment zone containing a material catalytically active in hydrotreatment under hydrotreatment conditions, said two phase stabilized feed comprising a liquid phase comprising at least an amount of said stabilized hydrocarbonaceous product and a gaseous phase comprising an amount of a high temperature section gas and optionally an amount of said stabilization section gas and withdrawing a two phase hydrotreated hydrocarbon stream from said hydrotreatment zone andseparating said two phase hydrotreated hydrocarbon stream in a high temperature section gas and a hydrocarbon product d. and optionally directing an amount of said stabilization section gas to be comprised in said first gaseous phase characterized in said stabilization zone operating in a temperature range below that of said hydrotreatment zone.

[0044] This has the associated benefit of separating the gas flows of the stabilization zone and the high temperature zone, such that the stabilization zone is not contaminated by impurities from the high temperature zone. The high temperature recycle gas and, if recycled, the stabilization section gas require gas compressors to drive the recycle, but the cost of this may be lower than the cost of mitigating corrosion and precipitation of ammonium halides. The stabilization section gas may be used within the same process, by recycle or direction downstream to the high temperature section or be directed to other processes in the same plant.

[0045] A second embodiment, relates to a process according to the first embodiment wherein stabilization hydrotreatment conditions involve a temperature range of at least 80°C, 100°C or 150°C and below 200°C 220°C or 250°C, a pressure from 0.5 MPag to 25 MPag, and a gas to oil ratio from 200 Nm3 / m3to 5000 Nm3 / m3.

[0046] This has the associated benefit of mild reaction conditions, removing reactive structures, without enabling excessive undesired reactions resulting e.g. in polymerization. It may be convenient to configure the stabilization in two steps; one operating in the range from 80°C to 150°C to stabilize the most reactive compounds with minimal risk of thermal runaway and a stabilization of the remaining reactive compounds at a higher range from 150°C to 250°C, such that the stabilized product is ready for bulk hydrotreatment.

[0047] A third embodiment relates to a process according the first or second embodiment, wherein said material catalytically active in selective hydrogenation comprises one or more metals in sulfided form from the group comprising Ni, Co, Mo and W, on a porous support comprising one or more refractive materials from the group comprising alumina, silica, titania and active carbon.

[0048] This has the associated benefit of being cost effective materials for the selective hydrogenation reactions.

[0049] A fourth embodiment relates to a process according the first or second embodiment, wherein said material catalytically active in selective hydrogenation comprises one or more metals in reduced form from the group comprising Pt, Pd, Ru, Rh, Ni, Cu, Mo, Co and W, on a porous support comprising one or more refractive materials from the group comprising alumina, silica, titania and active carbon.

[0050] This has the associated benefit of being active and selective materials for the selective hydrogenation reactions, operating in an environment which does not contains sulfur or nitrogen. Preferred compositions include combinations of Ni and Cu, Ni and Mo, Pt and Pd and Mo and activated carbon.

[0051] A fifth embodiment relates to a process according any of the above embodiments, wherein hydrotreatment involves a least partial hydrodeoxygenation and optionally also hydroconversion.

[0052] This has the associated benefit of providing a hydrocarbon product, which has a higher energy density and stability, compared to fuels with higher amounts of oxygenates. If hydroconversion is involved this may be either hydrocracking, hydroisomerization or both. If hydrocracking is involved, the effect is a reduction of the end boiling point of the product, and if hydroisomerization is involved, the effect is an improvement of cold flow properties, and possibly also suitability of the product for use in steam cracking.

[0053] A sixth embodiment relates to a process according any of the above embodiments, wherein hydrotreatment is carried out at hydrotreatment conditions in the presence of a material catalytically active in hydrotreatment, and wherein hydrotreatment conditions involve a temperature range above 250°C or 300°C and below 400°C or 420°C, a pressure above 0.5 MPag or 5 MPag and below 20 MPag or 25 MPag, and a gas to oil ratio from 200 Nm3 / m3to 10000 Nm3 / m3and said material catalytically active in hydrodeoxygenation comprises one or more metals in sulfided form from the group comprising Ni, Co, Mo and W on a porous support comprising one or more refractive materials from the group comprising alumina, silica, titania, and active carbon.

[0054] This has the associated benefit of mild reaction conditions, removing reactive structures, without enabling excessive undesired reactions resulting e.g. in oligomerization.

[0055] A seventh embodiment relates to a process according any of the above embodiments, wherein hydroconversion is carried out at hydrocracking conditions in the presence of a material catalytically active in hydrocracking, and wherein hydroconversion conditions involve a temperature range above 250°C or 300°C and below 400°C or 420°C, a pressure above 0.5 MPag or 5 MPag and below 20 MPag or 25 MPag, and a gas to oil ratio from 200 Nm3 / m3to 10000 Nm3 / m3and said material catalytically active in hydroconversion comprises either, one or more metals in sulfided form from the group comprising Ni, Co, Mo and W, or one or more metals in elemental form from the group comprising Ru, Rh, Pt or Pd, on a porous support comprising one or more refractive materials from the group comprising alumina, silica, titania, silica-alumina, zeolites and active carbon.

[0056] This has the associated benefit of converting the structure of the hydrotreated product, e.g. by converting the boiling point or cold flow properties to more favorable properties. The reactions may take place in the presence of a single catalytically active material or multiple catalytically active materials chosen for each their specific conversion abilities.

[0057] A eighth embodiment relates to a process according any of the above embodiments,, wherein said reactive hydrocarbonaceous mixture comprises at least 1 pprriwt, 10 ppmwt or 50 ppmwt and less than 500 ppmwt, 5000 ppm wt or 10000 ppmwt Cl.

[0058] This has the associated benefit of providing a process where Cl released at low temperatures is kept separate from other released heteroatoms released at more severe conditions.

[0059] A ninth embodiment relates to a process according any of the above embodiments, wherein said reactive hydrocarbonaceous mixture comprises at least 10 ppmwt or 50 ppmwt and less than 500 ppmwt, 5000 ppm wt or 10 wt% N.

[0060] This has the associated benefit of providing a process handling N released at elevated temperatures separately from other released heteroatoms released at mild conditions. Such a process may be beneficial at very high levels - such as atleast 500 ppmwt or 5000 ppmwt keeping ammonia from disturbing specific catalysts especially reduced metal catalysts. But a process may also be beneficial at low levels - such as from 1 ppmwt or ppmwt up to 500 ppmwt or 5000 ppmwt where recycle may increase the ammonia concentration and cause undesired precipitation of corrosive compounds.

[0061] A tenth embodiment relates to any embodiment above wherein the stabilization section recycle gas comprises less than 0.5 ppbvoi, 1 ppbvoi or 5 ppbvoi ammonia.

[0062] This has the associated benefit of avoiding precipitation of ammonium halides in processes where organically bound halides are released at stabilization conditions, while organically bound nitrogen is not.

[0063] A eleventh embodiment relates to any embodiment above to wherein the stabilization section recycle gas comprises less than 0.5 ppbvoi, 1 ppbvoior 5 ppbvoi halides.

[0064] This has the associated benefit of avoiding precipitation of ammonium halides in processes where organically bound nitrogen are released at stabilization conditions, while organically bound halides is not. This may be especially relevant in the case of feedstock comprising ultrastable PFAS compounds or biological feedstocks with reactive organically bound nitrogen.

[0065] A eleventh embodiment relates to any embodiment above to wherein an amount of said high temperature section gas is either withdrawn from the process as purge or is purified and directed to be comprised in said first gaseous phase.

[0066] This has the associated benefit of withdrawing impurities from the high temperature section recycle gas to minimize built up of halides as well as ammonia.

[0067] A further aspect relates to a process plant comprising a stabilization reactor section comprising a stabilization gas loop, comprising a stabilization section recycle gas compressor, and a high temperature reactor section comprising a high temperature gas loop, comprising a high temperature section recycle gas compressor, configured for carrying out a process according to any embodiment above.

[0068] This has the associated benefit of a reduced cost of equipment by segregating gas flows such that corrosive precipitation is avoided and corrosion resistant materials are avoided or reduced, which results in a reduced overall cost, even if two recycle gas compressors are required.Brief Description of Drawings

[0069] Fig.1 shows a process with two gas loops according to the present disclosure.

[0070] Fig.2 shows a process with a single gas loop according to the present disclosure.Fig.1

[0071] Fig-.1 shows a process with two gas loops according to the present disclosure. A reactive hydrocarbonaceous mixture (102) is combined with a first hydrogen rich recycle stream (104) comprising small amounts of water, hydrogen chloride and carbon oxides and a stabilization make-up hydrogen stream (106) to form a two-phase stabilization section feed stream (108) which is heated to mild stabilization temperature, such as 120°C in a feed heat exchanger (HX-F) and directed to a first stabilization reactor (ST-A) in which the most reactive constituents of two-phase stabilization section feed stream (108) are saturated and partially hydrotreated to form an intermediate stabilized steam (110), which contains HCI and water formed during mild stabilization, in addition to the stabilized hydrocarbonaceous mixture and hydrogen. The temperature of the intermediate stabilized steam (110) is adjusted to a second stabilization temperature in a stabilization section heat exchanger (HX-S) which according to the specific situation may be configured for heating or cooling the intermediate stabilized stream (110) before the stream directed to the second stabilization reactor (ST-B). The two phase stabilized product (112) is combined with a second make-up hydrogen stream (114), cooled to 50°C in an intermediate exchanger (HX-I) and separated in a separator (SEP) to provide a stabilized oil stream (116), an optional sour water stream (117) and a gas stream which is split into a stabilization gas loop purge stream (118) and a stabilization gas loop recycle stream (119) which is pressurized in a stabilization gas loop compressor (CMP-S) to form said hydrogen rich recycle stream (104).

[0072] All streams in the stabilization zone are absent of ammonia, and thus, no concern over precipitation of ammonium chloride is needed, and all reactors and equipment may be made in carbon steel.

[0073] The stabilized oil stream (116) is combined with a hydrogen rich gas stream (144) comprising ammonia, carbon oxides and water to form a high temperature section feed stream (120), which is preheated in a feed-effluent heat exchanger (HX-FE) and depending on heat released in hydrotreatment possibly also in a fired heater (FH), and first directed to a guard zone (GRD) comprising catalytically active material suited for capturing heteroatoms released in solid form, providing a purified hydrocarbonaceous stream (122). Here the guard zone is shown as a single reactor, but in practice it may be configured as multiple reactors, e.g. 4, and these reactors may be configured for individual temperature control and with possibilities for blocking the flows to allow for replacement of catalytically active material without shutting down the process plant entirely. The purified hydrocarbonaceous stream (122) is directed to a hydrodeoxygenation zone (HDO), which again for simplicity is shown as a single reactor, but may be multiple reactors, e.g. 2. It is also possible to configure the guard zone and the hydrodeoxygenation zone in a single reactor, if this matches process capacities.

[0074] The gas phase of the two phase hydrotreated hydrocarbon stream (124) will contain released heteroatoms; oxygen will mainly be released as water, but some amount of oxygen will also be released as carbon oxides, and organically bound nitrogen, and sulfur if present will have been released to the gas phase and ammonia and hydrogen sulfide. The liquid phase of the product of hydrodeoxygenation may be substantially absent of oxygen and other heteroatoms, or some may remain, depending on process configuration and requirements for the product. The two phase hydrotreated hydrocarbon stream (124) will be hot due to the exothermic reactions, and the released heat is used to heat the high temperature section feed stream (120) in the feed-effluent heat exchanger (HX-FE). The cooled two phase hydrotreated hydrocarbon stream (124) is optionally combined with a soak gas (126), directed to a hot high- pressure separator (HHPS), separating hot oil (128) from hot gas (130), which is cooled in an air cooler (COOL) and directed to a cold high-pressure separator (CHPS), separating cold gas (132), cold oil (134) and water (136). Capture ofammonia, hydrogen chloride and other heteroatom-products may be enhanced by washing with recirculated water (136) via a pump (PUMP) and withdrawn as sour water (137). Here hot oil and cold oil are shown to be combined into hydrocarbon product (138) but in practice this combination may be made via a product stripper removing dissolved gas from the product. The cold gas (132) is split in an amount directed as gas purge (140) and an amount directed as high temperature section gas (142) after being pressurized in the high temperature gas loop compressor (CMP-H). The high temperature section gas (142) is combined with the stabilization gas loop purge stream (118) to form the second hydrogen rich gas (144) for the high temperature hydrotreatment zone. The combination of these streams with the stabilized oil stream (116), must be made in consideration of the temperatures and composition of the streams to avoid problematic precipitation of ammonium chloride.

[0075] Make up hydrogen gas (146) is shown to be provided in three streams; stabilization make-up hydrogen stream (106), second make-up hydrogen stream (114) and soak gas (126) - but only the provision of pure hydrogen to the stabilization zone is essential to the present disclosure.

[0076] Hydrogen chloride will be purged to the high temperature hydrotreatment section, but even though organically bound nitrogen is released as ammonia, there will only be a combined presence of ammonia and hydrogen chloride in high temperature sections or after the addition of water (136) such that precipitation will not occur, and concentration by recycle is avoided by withdrawal in sour water (137).Fig.2

[0077] Fig.2 shows a comparative process with a single gas loop. A reactive hydrocarbonaceous mixture (102) is combined with a common hydrogen rich recycle stream (105), comprising small amounts of ammonia, carbon oxides and water to form a two-phase stabilization section feed stream (108) which is heated to mild stabilization temperature, such as 120°C in a feed heat exchanger (HX-F) and directed to a first stabilization reactor (ST-A) in which the most reactive constituents of two-phase stabilization section feed stream (108) are saturated and partially hydrotreated to form an intermediate stabilized steam (110), whichcontains HCI and water formed during mild stabilization, in addition to the stabilized hydrocarbonaceous mixture and hydrogen. The temperature of the intermediate stabilized steam (110) is adjusted to a second stabilization temperature in a stabilization section heat exchanger (HX-S) which according to the specific situation may be configured for heating or cooling the intermediate stabilized stream (110) before the stream directed to the second stabilization reactor (ST-B). The two-phase stabilized product (112) is combined with a main make-up hydrogen stream (115), to form a high temperature zone feed stream (120).

[0078] The high temperature section feed stream (120) is preheated in a feedeffluent heat exchanger (HX-FE) and depending on heat released in hydrotreatment possibly also in a fired heater (FH), and first directed to a guard zone (GRD) comprising catalytically active material suited for capturing heteroatoms released in solid form, providing a purified hydrocarbonaceous stream (122). Here the guard zone is shown as a single reactor, but in practice it may be configured as multiple reactors, e.g. 4, and these reactors may be configured for individual temperature control and with possibilities for blocking the flows to allow for replacement of catalytically active material without shutting down the process plant entirely. The purified hydrocarbonaceous stream (122) is directed to a hydrodeoxygenation zone (HDO), which again for simplicity is shown as a single reactor, but may be multiple reactors, e.g. 2. It is also possible to configure the guard zone and the hydrodeoxygenation zone in a single reactor, if this matches process capacities.

[0079] The gas phase of the two phase hydrotreated hydrocarbon stream (124) will contain released heteroatoms; oxygen will mainly be released as water, but some amount of oxygen will also be released as carbon oxides, and organically bound nitrogen, and sulfur if present will have been released to the gas phase and ammonia and hydrogen sulfide. The liquid phase of the product of hydrodeoxygenation may be substantially absent of oxygen and other heteroatom, or some may remain, depending on process configuration and requirements for the product. The two phase hydrotreated hydrocarbon stream (124) will be hot due to the exothermic reactions, and the released heat is used to heat the high temperature section feed stream (120) in the feed-effluent heat exchanger (HX-FE). The cooled two phase hydrotreated hydrocarbon stream (124) is optionally combined with a soak gas (126), directed to a hot high-pressure separator (HHPS), separating hot oil (128) from hot gas (130), which is cooled in an air cooler (COOL) and directed to a cold high-pressure separator (CHPS), separating cold gas (132), cold oil (134) and water (136). Capture of ammonia, hydrogen chloride and other heteroatom-products may be enhanced by washing with recirculated water (136) via a pump (PUMP) and withdrawn as sour water (137). Here hot oil and cold oil are shown to be combined into hydrocarbon product (138) but in practice this combination may be made via a product stripper removing dissolved gas from the product. The cold gas (132) is split in an amount directed as gas purge (140) and an amount directed as common hydrogen rich recycle stream (105) after being pressurized in the common gas loop compressor (CMP-C).

[0080] Make up hydrogen gas (146) is provided in two streams; main make-up hydrogen stream (115) and soak gas (126).

[0081] As organically bound nitrogen is released as ammonia, there will be a combined presence of ammonia and hydrogen chloride, and precipitation may occur in low temperature equipment, such as the first stabilization reactor (ST-A) and the stabilization section heat exchanger (HX-S), and therefore it is required to clad this equipment with corrosion resistant materials, such as Alloy 625 steel.Description of Embodiments

[0082] Examples

[0083] A simulation was performed to evaluate the layouts corresponding to Fig.1 and Fig.2. The feedstock in the two examples are the same, and conversions are estimated to be identical, but the process gas flows are different.

[0084] Table 1 and 2 report the composition of selected flows in kmol / hr or mol / hr. For the oil composition the values are flows for the liquid mixture and for the gas stream, selected molecular flows are given, both under the assumption that no gases are dissolved in the oil. In addition a minor presence of carbon monoxide, carbon dioxide as well as methane and other light hydrocarbon is present but notreported. The estimation of precipitation temperature for the streams is made under the assumption that no gaseous compounds are dissolved in the liquid phase for two-phase flows, as mentioned above.

[0085] Characteristics of streams of the disclosed process according to Fig.1 is given in Table 1 . It can be seen that NH3 is absent from the stabilization section, and thus no risk of precipitation is present, in spite of the presence of 2-5 mol / hr HCI, and correspondingly in the high temperature section the temperature is above the precipitation temperature.

[0086] Similarly characteristics of streams of the process according to Fig.2 is given in Table 2. For the oil composition, elemental kmol / hr values are given and for the gas stream molecular kmol / hr values are given. It can be seen that out of stabilizer A (stream 110) the gas phase contains 0.043 mol / hr (0.06 pprnmoiar) NH3 and 1 .2 mol / hr (1 .7 pprnmoiar) HCI, which relates to a precipitation temperature of 126°C i.e. above the 119°C out of stabilizer A, and thus shows a risk of corrosive precipitation.

[0087] As a consequence of the risk of corrosive precipitation, the layout of Fig.2 must be designed with corrosion resistant materials, at least in stabilization reactor A and heat exchanger A, which will increase the cost of these elements. Fig.1 will have an increased cost of an additional compressor and a gas / liquid separator. Any other elements are assumed to be identical in the two layouts.

[0088] Table 3 is a comparison of the related costs of the two layouts by index values, with focus on the differences. The estimated cost of a plant as illustrated in Fig.2 (including a total of 8, not 4, reactors and a product stripping section not shown) is listed as index 100, and the summed cost of stabilization reactor A, heat exchanger A both in corrosion resistant Alloy 625 and the two recycle and makeup gas compressors is 10.4. In comparison the cost of the corresponding elements of Fig.1 is 8.4, which represents a substantial 2% reduction in the cost of the full plant, by the introduction of an extra gas loop and avoidance of expensive high grade materials.

[0089] Table 4 shows a thermodynamic calculation of the combined gas concentrations causing a risk of precipitation of ammonium chloride at 105°C, at two pressures, assuming a pure hydrogen gas. As it can be seen, design criteriafor NH3 in the stabilization section gas may be defined from the concentration of HCI in the stabilization section gas, either as a functional value of being below the concentration causing a precipitation temperature of ammonium halides or as not exceeding the specific values shown in Table 4. For HBr the critical compositions will be even lower, whereas for HF they would be higher, but trends would be comparable.Reference Signs ListProcess streams102 Reactive hydrocarbonaceous mixture104 First hydrogen rich stream105 Common hydrogen rich recycle stream106 Stabilization make-up hydrogen stream108 Two-phase stabilization section feed stream108 Two-phase stabilization section feed stream110 Intermediate stabilized steam112 Two phase stabilized product114 Second make-up hydrogen stream115 Main make-up hydrogen stream116 Stabilized oil stream118 Stabilization gas loop purge stream119 Stabilization gas loop recycle stream120 High temperature section feed stream122 Purified hydrocarbonaceous stream124 Two phase hydrotreated hydrocarbon stream126 Soak gas128 Hot oil stream130 Hot gas stream132 Cold gas134 Cold oil136 Recirculated cold oil138 Hydrocarbon product140 Gas purge142 High temperature section gas144 Second hydrogen rich gas146 Make up hydrogen gasProcess equipmentCH PS Cold high pressure separatorCMP-C Common gas loop compressorCMP-H High temperature gas loop compressorCMP-S Stabilization gas loop compressorCOOL Air coolerFH Fired heaterFLSH Flash drumGRD Guard zoneHDO Hydrodeoxygenation zoneHHPS Hot high pressure separatorHX-F Feed heat exchangerHX-FE Feed-effluent heat exchangerHX-I Intermediate exchangerHX-S Stabilization section heat exchangerMLIGC Make-up gas compressorPUMP PumpST-A First stabilization reactorST-B Second stabilization reactorTable 1Table 2Table 3Table 4

Claims

Claims

1. A process for conversion of a reactive hydrocarbonaceous mixture comprising at least 0.5 ppmwt halides and at least 5 ppmwt nitrogen to a hydrocarbon product comprising the steps in a stabilization section a. directing a two-phase feed to a stabilization zone containing a material catalytically active in stabilization hydrotreatment under stabilization conditions, said two phase feed comprising a liquid phase comprising said reactive hydrocarbonaceous mixture and a first gaseous phase comprising an amount of make-up hydrogen gas b. withdrawing a two-phase stabilized product from said stabilization zone and separating said two-phase stabilized product into a stabilization section gas and a stabilized hydrocarbonaceous product and comprising the steps in a high temperature section operating at a temperature above the temperature of the stabilization section c. directing a two-phase stabilized feed stream to a hydrotreatment zone containing a material catalytically active in hydrotreatment under hydrotreatment conditions, said two phase stabilized feed comprising a liquid phase comprising at least an amount of said stabilized hydrocarbonaceous product and a gaseous phase comprising an amount of a high temperature section gas and optionally an amount of said stabilization section gas and withdrawing a two phase hydrotreated hydrocarbon stream from said hydrotreatment zone and separating said two phase hydrotreated hydrocarbon stream into a high temperature section gas and a hydrocarbon product, d. and optionally directing an amount of said stabilization section gas to be comprised in said first gaseous phase,characterized in said stabilization zone operating in a temperature range below that of said hydrotreatment zone.

2. A process according to claim 1 wherein stabilization hydrotreatment conditions involve a temperature range of at least 80°C, 100°C or 150°C and below 200°C 220°C or 250°C, a pressure from 0.5 MPag to 25 MPag, and a gas to oil ratio from 200 Nm3 / m3to 5000 Nm3 / m3.

3. A process according to claim 1 or 2 wherein said material catalytically active in selective hydrogenation comprises one or more metals in sulfided form from the group comprising Ni, Co, Mo and W, on a porous support comprising one or more refractive materials from the group comprising alumina, silica, titania and active carbon.

4. A process according to claim 1 or 2 wherein said material catalytically active in selective hydrogenation comprises one or more metals in reduced form from the group comprising Pt, Pd, Rh, Ru, Ni, Cu, Mo, Co and W, on a porous support comprising one or more refractive materials from the group comprising alumina, silica, titania and active carbon.

5. A process according to claim 1 , 2, 3 or 4, wherein hydrotreatment involves a least partial hydrodeoxygenation and optionally, also hydroconversion.

6. A process according to claim 1 , 2, 3, 4 or 5, wherein hydrotreatment is carried out at hydrotreatment conditions in the presence of a material catalytically active in hydrotreatment, and wherein hydrotreatment conditions involve a temperature range above 250°C or 300°C and below 400°C or 420°C, a pressure above 0.5 MPag or 5 MPag and below 20 MPag or 25 MPag, and a gas to oil ratio from 200 Nm3 / m3to 10000 Nm3 / m3and said material catalytically active in hydrodeoxygenation comprises one or more metals in sulfided form from the group comprising Ni, Co, Mo and W on a porous support comprising one or more refractive materials from the group comprising alumina, silica, titania, and active carbon.

7. A process according to claim 1 , 2, 3, 4, 5 or 6, wherein hydroconversion is carried out at hydrocracking conditions in the presence of a material catalytically active in hydrocracking, and wherein hydroconversion conditions involve a temperature range above 250°C or 300°C and below400°C or 420°C, a pressure above 0.5 MPag or 5 MPag and below 20 MPag or 25 MPag, and a gas to oil ratio from 200 Nm3 / m3to 10000 Nm3 / m3and said material catalytically active in hydroconversion comprises either one or more metals in sulfided form from the group comprising Ni, Co, Mo and W, or one or more metals in elemental form from the group comprising Ru, Rh, Pt or Pd, on a porous support comprising one or more refractive materials from the group comprising alumina, silica, titania, silica-alumina, zeolites and active carbon.

8. A process according to claim 1 , 2, 3, 4, 5, 6 or 7, wherein said reactive hydrocarbonaceous mixture comprises at least 1 ppmwt, 10 ppmwt or 50 pprriwt and less than 500 ppmwt, 5000 ppm wt or 10000 ppmwt Cl.

9. A process according to claim 1 , 2, 3, 4, 5, 6, 7 or 8, wherein said reactive hydrocarbonaceous mixture comprises at least 10 ppmwt or 50 ppmwt and less than 500 ppmwt, 5000 ppm wt or 10 wt% N.

10. A process according to claim 1 , 2, 3, 4, 5, 6, 7, 8 or 9, wherein the stabilization section recycle gas comprises less than 0.5 ppbvoi, 1 ppbvoi or 5 ppbvoi ammonia.

11. A process according to claim 1 , 2, 3, 4, 5, 6, 7, 8 or 9, wherein the stabilization section recycle gas comprises less than 0.5 ppbvoi, 1 ppbvoior 5 ppbvoi hydrogen halides.

12. A process according to claim 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11 , wherein an amount of said high temperature section gas is either withdrawn from the process as purge or is purified and directed to be comprised in said first gaseous phase.

13. A process plant comprising a stabilization reactor section comprising a stabilization gas loop, comprising a stabilization section recycle gas compressor, and a high temperature reactor section comprising a high temperature gas loop, comprising a high temperature section recycle gas compressor, configured for carrying out a process according to any claim above.

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