Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
  • C10G45/58—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G47/00—Cracking of hydrocarbon oils, in the presence of hydrogen or hydrogen- generating compounds, to obtain lower boiling fractions
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G65/00—Treatment of hydrocarbon oils by two or more hydrotreatment processes only
  • C10G65/02—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only
  • C10G65/12—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only including cracking steps and other hydrotreatment steps
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
  • C10G2300/10—Feedstock materials
  • C10G2300/1022—Fischer-Tropsch products

Definitions

• the present invention is directed to a process to prepare Fischer-Tropsch derived middle distillates and base oils.
• a problem of the process as disclosed in US 6,635,171 B2 is that although the catalytic activity of the dewaxing catalyst and the obtained lubes yield is achieved, extra process steps (purification, monitoring and adjustment) need to be followed to reduce the nitrogen content of Fischer-Tropsch products used as feedstock for the hydrotreating step, below a threshold value. Moreover, if the nitrogen content of the purified Fischer-Tropsch product increases (monitoring step), the severity of the hydrotreating step (purification step) must be increased to compensate for this increase (adjustment). To obtain lubes with the process in US6,635,171 B2 a lot of extra steps are necessary and therefore making that process complex and capex intensive.
• Another object of the invention is to provide an efficient method for preparation of high yield middle distillates with excellent cold flow properties and a high yield of base oils.
• One of the above or other objects may be achieved according to the present invention by providing a process to prepare at least middle distillates and base oils from a Fischer-Tropsch derived feedstock, by
• An advantage of the present invention is that although the catalyst activity is affected by the presence of the nitrogen containing compounds and hence the catalytic reaction takes place at a higher operating temperature, no negative impact on the yield profile is observed but surprisingly higher yields are obtained.
• a further advantage of the present invention is that not only the presence of nitrogen containing compounds but also the addition of an increasing amount of added nitrogen containing compounds enacts that base oils and gasoil are obtained with better properties.
• a Fischer-Tropsch derived feedstock is provided containing nitrogen through addition of a nitrogen containing compound selected from ammonia, HCN, NO, amines, nitriles and a heterocyclic compound containing at least one nitrogen atom as ring member of a heterocyclic ring to a Fischer-Tropsch reactor.
• a nitrogen containing compound selected from ammonia, HCN, NO, amines, nitriles and a heterocyclic compound containing at least one nitrogen atom as ring member of a heterocyclic ring
• the Fischer-Tropsch derived feedstock is a product derived from a Fischer-Tropsch process.
• Fischer-Tropsch product is known in the art.
• Fischer-Tropsch product is meant a synthesis product of a Fischer-Tropsch process.
• Synthesis gas or syngas is a mixture of hydrogen and carbon monoxide that is obtained by conversion of a hydrocarbonaceous feedstock.
• Suitable feedstocks include natural gas, crude oil, heavy oil fractions, coal, biomass and lignite.
• a Fischer-Tropsch product may also be referred to as GTL (Gas-to-Liquids) product.
• GTL Gas-to-Liquids
• Fischer-Tropsch product of the Fischer-Tropsch process is usually separated into a water stream, a gaseous stream comprising unconverted synthesis gas, carbon dioxide, inert gases and C1 to C2, and a C3+ product stream by distillation.
• a gaseous stream comprising unconverted synthesis gas, carbon dioxide, inert gases and C1 to C2
• C3+ product stream by distillation.
• Commercially available equipment can be used.
• the distillation may be carried out at atmospheric pressure, but also reduced pressure may be used.
• Fischer-Tropsch product stream in step (a) is preferably meant the C3+ product stream.
• the Fischer-Tropsch feedstock comprises 81% of compounds boiling above 370 °C and 49% of compounds boiling above 540 °C.
• the Fischer-Tropsch derived feedstock as provided in step (a) is prepared by adding to a gaseous feed stream comprising hydrogen and carbon monoxide a nitrogen containing compound to obtain a mixture wherein the nitrogen containing compound is selected from ammonia, HCN, NO, amines, nitriles and a heterocyclic compound containing at least one nitrogen atom as ring member of a heterocyclic ring.
• a nitrogen-containing compound is added such that the nitrogen-containing compound is present in the gaseous feed stream in a concentration of up to 10 ppmV.
• the nitrogen-containing compound is added to the gaseous feed stream such that the nitrogen-containing compound is present in the gaseous feed stream in a concentration in the range of 0.05 to 10 ppmV.
• the obtained mixture is then fed to a Fischer-Tropsch reactor to obtain a Fischer-Tropsch feedstock containing nitrogen through the addition of a nitrogen containing compound selected from ammonia, HCN, NO, amines, nitriles and a heterocyclic compound containing at least one nitrogen atom as ring member of a heterocyclic ring to the gaseous feed stream.
• a nitrogen containing compound selected from ammonia, HCN, NO, amines, nitriles and a heterocyclic compound containing at least one nitrogen atom as ring member of a heterocyclic ring
• the Fischer-Tropsch product stream as provided in step (a) comprises paraffins having from 3 to 300 carbon atoms.
• the Fischer-Tropsch derived feedstock as provided in step (a) is prepared by adding to a Fischer-Tropsch product stream as obtained from a Fischer-Tropsch process a nitrogen containing compound selected from ammonia, HCN, NO, amines, nitriles and a heterocyclic compound containing at least one nitrogen atom as ring member of a heterocyclic ring.
• a nitrogen containing compound selected from ammonia, HCN, NO, amines, nitriles and a heterocyclic compound containing at least one nitrogen atom as ring member of a heterocyclic ring.
• the Fischer-Tropsch product stream to which the nitrogen containing compound is added comprises paraffins having from 5 to 300 carbon atoms.
• the nitrogen containing compound (expressed as concentration of Nitrogen (N)) added to the Fischer-Tropsch product is in the range from 0.1 to 20 ppmw, preferably from 0.2 to 17 ppmw, more preferably from 0.3 to 14 ppmw, even more preferably from 0.4 to 12 ppmw.
• the nitrogen is present in the Fischer-Tropsch feedstock of step (a) in a concentration between 0.5 and 10 ppmw.
• the nitrogen containing compound comprises amines. More preferably, the amine is decylamine.
• the amount of decylamine added to the Fischer-Tropsch product is in the range of from 1 to 225 ppmw, preferably from 2 to 191 ppmw, more preferably from 3 to 157 ppmw, even more preferably from 4 to 135 ppmw, most preferably from 60 to 112 ppmw. These ranges are equivalent to the following concentrations of nitrogen (N) in the range of from 0.1-20 ppmw.
• step (b) of the process according to the present invention the feedstock of step (a) is subjected to a hydroprocessing step in the presence of one or more catalysts to obtain a first mixture comprising one or more middle distillate fractions and a first residual fraction and naphtha fraction.
• Hydroprocessing in step (b) may take place in a heavy paraffin conversion unit. In this unit, preferably in the presence of one or more catalysts of step (b) both hydrocracking and hydroisomerization takes place.
• step (b) the Fischer-Tropsch feedstock is contacted in the presence of hydrogen, at a pressure in the range of 20 to 100 barg and at a temperature between 250 and 400°C.
• step (b) takes place at a pressure in the range of from 30 to 70 barg and at a temperature between 300 and 400°C. Hydrocracking/hydroisomerization processes are known in the art and therefore not discussed here in detail.
• Hydrocracking/hydroisomerization and the effect of hydrocracking/hydroisomerization conditions on the amount of isomerised product are for example described in Chapter 6 of "Hydrocracking Science and Technology", Julius Scherzer; A. J. Cruia, Marcel Dekker, Inc, New York, 1996, ISBN 0-8247-9760-4 .
• Step (b) takes place in the presence of one or more catalysts.
• one or more catalyst of step (b) comprises a Group VIII noble metal supported on an amorphous acidic carrier.
• the one or more catalysts of step (b) comprise a Group VIII noble metal supported on an amorphous acidic carrier as a hydroprocessing catalyst.
• step (b) Preparation of the hydroprocessing catalyst utilized in step (b) is for example described in WO2011/064236 .
• one or more catalyst of step (b) comprises a Group VIII metal and a medium pore size molecular sieve.
• the one or more catalysts of step (b) comprising a Group VIII metal and a medium pore size molecular sieve is a catalytic dewaxing catalyst.
• step (b) Preparation of the dewaxing catalysts utilized in step (b) is for example described in WO2015/063213 .
• step (b) takes place in the presence of a stacked bed of catalysts.
• the stacked bed of catalyst are two different catalysts in series, wherein hydroprocessing of the Fischer-Tropsch feedstock of step (b) takes place by contacting the Fischer-Tropsch feedstock with a first catalyst having hydrocracking and hydroisomerising activity and then with a second catalyst having hydrocracking and hydroisomerising activity, wherein the second catalyst is more active in hydroisomerisation and less active in hydrocracking compared to the first catalyst.
• the first catalyst comprises a Group VIII noble metal supported on an amorphous acidic carrier and the second catalyst comprises a Group VIII metal and a medium pore size molecular sieve.
• Preparation of the catalysts used in the stacked bed in step (b) is for example described in WO2015/063213 and WO2011/064236 .
• step (c) of the process according to the present invention the first mixture as obtained in step (b) is separated by means of atmospheric distillation into one or more middle distillate fractions, a first residual fraction and a naphtha fraction.
• the one or more middle distillate fractions may comprise a single middle distillate fraction, for example a single fraction having a majority of components, for instance 95vol% or greater, boiling in the range of from 150°C to 400°C.
• This single fraction is preferably a wide range gasoil.
• gasoil fraction will usually contain a majority of components having boiling points within the typical diesel fuel (“gasoil”) range, i.e.
• gasoil fraction is typically a wide range heavy gasoil fraction.
• the catalyst activity is affected by the presence of the nitrogen containing compounds in step (b) of the process according to the present invention and hence the catalytic reaction takes place at a higher operating temperature, no negative impact on the yield profile is observed but surprisingly higher yields in middle distillates are obtained compared to a reaction without the presence of nitrogen containing compound.
• the cloud point of the gasoil fraction improves upon addition of an increasing amount of nitrogen containing compound compared to the cloud point of the gasoil fraction reached without the addition of nitrogen containing compound.
• the cloud point of the gasoil fraction (wide range or heavy gasoil) is preferably below -10°C, preferably between -15 and -35°C and is therefore suitable for the production of Nordic/and or arctic grade diesel and/or diesel blending components.
• the wide range gasoil can be distilled into a kerosene fraction and a heavy gasoil fraction.
• the kerosene fraction as obtained in step c) has a freezing point below -40°C.
• the kerosene fraction as obtained in step c) according to the process of the present invention has cold flow properties which properties make the kerosene fraction suitable as ajet-A or even jet-Al blending component.
• the first residual fraction comprises compounds boiling above the middle distillate boiling range.
• the first residual fraction is a fraction of which at least 95 wt.% has a boiling point above 330°C.
• step (d) of the process of the present invention the first residual fraction is separated by means of vacuum distillation into at least a distillate base oil fraction and a second residual fraction.
• the second residual fraction thus obtained typically comprises compounds boiling above a temperature of 440°C.
• the boiling point at which 10wt.% of the second residual fraction from step (d) is recovered is in the range between 440 and 560°C according to ASTM D7169, more preferably the boiling point at which 5 wt.% is recovered is in the range between 440 and 560°C according to ASTM D7169.
• the second residual fraction is also known as a vacuum bottoms product.
• the second residual fraction may undergo a subsequent dewaxing step to obtain extra heavy base oil with a better pour point.
• extra heavy base oil is meant a residual base oil.
• the second residual fraction is a residual base oil.
• step (b) in which in step (b) a hydroprocessing catalyst or a stacked bed of catalysts is used, the second residual fraction is further dewaxed to obtain a residual base oil.
• the residual base oil has a pour point below -5°, preferably in a range between -10°C and -40°C. Also, the residual base oil has a kinematic viscosity at 100°C in a range between 10 and 35 cSt, preferably between 12 and 30 cSt.
• step (a) At least part of the second residual fraction is recycled to step (a).
• reference herein to the feedstock to step (a) is to the combined feedstock i.e. to the total of fresh feedstock and any recycled fraction.
• the distillate base oil fraction as obtained in step (d) will have an intermediate boiling range.
• the boiling point at which 90wt.% of the distillate base oil fraction from step (c) is recovered is in the range of from 420 and 560°C according to ASTM D2887.
• the process according to the present invention comprises a further step (e) wherein the distillate base oil fraction is fractionated in one or more base oils.
• step (b) of the process according to the present invention Although the catalyst activity is affected by the presence of the nitrogen containing compounds in step (b) of the process according to the present invention and hence the catalytic reaction takes place at a higher operating temperature, no negative impact on the yield profile is observed but surprisingly higher yields in distillate base oils and therefore also base oils are obtained.
• the distillate base oil fraction obtained in step (d) may not be sufficiently isomerized.
• the distillate base oil fraction of step (d) is catalytically dewaxed to obtain one or more base oils.
• This distillate base oil fraction is also known as a waxy raffinate fraction.
• This waxy raffinate fraction may be further dewaxed and fractionated in one or more base oils and optionally an isomerized gasoil fraction, preferably in a base oil having a kinematic viscosity according to ASTM D445 at 100°C in a range of from 1.2 to 3 Cst and/or a base oil having a kinematic viscosity at 100°C in a range of from 3 to 5 Cst and/or in a base oil having a kinematic viscosity at 100 °C in a range of from 5 to 7 and/or in a base oil having a kinematic viscosity according to ASTM D445 at 100°C in a range of from 7 to 9 Cst.
• the yield of waxy raffinate fraction as obtained in step d) according to the process of the present invention increases upon increasing amount of nitrogen containing compound.
• the pour point of the waxy raffinate deceases upon the addition of an increasing amount of nitrogen compound. Both effects are surprising because the catalyst is affected by the presence of a nitrogen containing compound which results in performing the catalytic reaction in step (b) at higher temperature compared to a reaction without the presence of a nitrogen containing compound.
• the distillate base oil fraction obtained in step (d) is sufficiently isomerized and may be separated in one or more base oils and optionally an isomerized gasoil fraction.
• the distillate base oil fraction is separated in various base oils with a kinematic viscosity at 100°C in a range of from 1.2 to 9Cst.
• a noble metal containing hydrocracking catalyst consisting of 0.8 wt% platinum on a carrier containing 70 wt% silica-alumina and 30% binder was mixed in a 1:2 v/v ratio with silicon carbide and loaded into the reactor.
• the catalyst was reduced in hydrogen at 400 °C for two hours and tested with a Fischer-Tropsch feedstock comprising 81% of compounds boiling above 370 °C and 49% of compounds boiling above 540 °C.
• the N content as measured with modified ASTM D5762 was below detection limit of ⁇ 0.5 ppmw.
• a total pressure of 60 bar was applied. Hydrogen with a purity of > 99% was added with a gas-hourly-space-velocity of 1250 Nl/lcatalyst/h.
• the fresh liquid feed weight-hourly-space-velocity was 0.8 kg/lcatalyst/h.
• the reaction products were separated with an atmospheric and vacuum distillation into a gaseous stream (C1-175°C), a liquid fraction (middle distillates (175-370°C), an intermediate liquid fraction (waxy raffinate fraction) and a heavy liquid fraction.
• the heavy liquid fraction was fully recycled to the inlet of the reactor. The recycle rate was chosen such that no accumulation of the heavy fraction in the system took place.
• Each fraction was analysed separately.
• the gaseous fraction was analysed with an online GC, the liquid fractions were collected over 24 hour periods and analysed by ASTM D 2887 (light fraction), ASTM D-2887 for the intermediate liquid fraction, whereas ASTM D7169-05 was used for the heavy fraction.
• the total product yield was calculated on the compositional data obtained for each stream and the quantity of hydrocarbon product in each stream.
• the conversion level was determined using atmospheric boiling point distributions for liquid feed and hydrocarbon products.
• the conversion 540°C+ material in the feed was varied by changing the Weight Average Bed Temperature over the reactor.
• the yield of the different product fractions was calculated on the basis of the generated data.
• the Fischer-Tropsch feedstock was used as is.
• Table 1 the results obtained in above experiment at ⁇ 70% conversion of 540°C+ material is given.
• a noble metal containing hydrocracking catalyst consisting of 0.8 wt% platinum on a carrier containing 66 wt% silica-alumina, 4% zeolite beta and 30% binder was mixed in a 1:2 v/v ratio with silicon carbide and loaded into the reactor.
• the catalyst was reduced in hydrogen at 400 °C for two hours and tested with two different Fischer-Tropsch feedstocks.
• the first feedstock comprised 90% of compounds boiling above 370 °C did contain no ( ⁇ 0.5 ppmw N), whereas the second feedstock comprised 87% of compounds boiling above 370 °C and contained 3 ppmw N, present as a range of amines.
• a total pressure of 38 bar was applied.
• Hydrogen with a purity of > 99% was added with a gas-hourly-space-velocity of 1000 Nl/lcatalyst/h .
• the fresh liquid feed weight-hourly-space-velocity was 1.0 kg/lcatalyst/h.
• the reaction products were separated into a gaseous stream, a liquid and a heavy liquid fraction. The reaction was run in once-through mode and each fraction was analysed separately.
• the gaseous fraction was analysed with an online GC, the liquid fractions were collected over 24-hour periods and analysed by ASTM D 2887 (light fraction) whereas ASTM D7169-05 was used for the heavy fraction.
• the total product yield was calculated on the compositional data obtained for each stream and the quantity of hydrocarbon product in each stream.
• the conversion level was determined using atmospheric boiling point distributions for liquid feed and hydrocarbon products.
• the conversion 370°C+ material in the feed was varied by changing the Weight Average Bed Temperature over the reactor.
• the yield of the different product fractions was
• Table 4 The results provided in Table 4 indicate a significantly improved selectivity: lower fraction of light products and increased middle distillate and waxy raffinate yield are found when amines are present in the feedstock.
• Table 3 Amines ppmw N 0 3 WABT 306 319 370 °C + conversion woff% 49 49 Lights yield (C 1 -175 °C) woff% 13.7 11.7 Middle distillate yield (175-370 °C) woff% 40.6 44.0 Waxy Raffinate yield (370-540 °C) woff% 25.3 27.4 Heavies yield (>540 °C) woff% 20.4 16.8

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• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

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Citations (8)

• 2020
  • 2020-11-19 EP EP20208595.7A patent/EP4001380A1/de not_active Withdrawn

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