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Jet fuel and arctic diesel fuel production by isodewaxing of waxy middle distillate fractions
Fuel xxx (2016) xxx–xxx
Contents lists available at ScienceDirect
Fuel journal homepage: www.elsevier.com/locate/fuel
Letter to the editor
Jet fuel and arctic diesel fuel production by isodewaxing of waxy middle distillate fractions Alena I. Grudanova ⇑, Ludmila A. Gulyaeva, Ludmila A. Krasilnikova, Olga I. Shmelkova, Roman E. Boldushevskii All-Russia Research Institute of Oil Refining JSC (VNII NP JSC), Aviamotornaya St. 6, Moscow 111116, Russia
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
Isodewaxing process for production
motor fuel with improved cold flow properties. The isodewaxing process can be used to expand the feedstock base for motor fuels production. Isodewaxing process produce jet fuel with chilling point < 62 °C. Isodewaxing process produce arctic diesel fuel with cold filter plugin point 49 °C. Total yield of motor fuels for operation at low ambient temperatures is 92% wt.
a r t i c l e
i n f o
a b s t r a c t Jet fuel with chilling point not higher than 60 °C below zero and arctic diesel fuel with cold filter plugin point not higher than 44 °C below zero are produced in the isodewaxing process developed by VNII NP JSC based on non-noble metal catalyst (NiMo/ZSM-11/mordenite). Resulting in pilot scale tests with isodewaxing catalyst load 65 cm3 during 170 h possibility of stable production of fuels met to regulation documents requirement was established. Study of group composition of target fuels shown the achievement of cold flow properties improvement is provided by the predominance in the fuels composition isoalkanes obtained during isodewaxing process. Ó 2016 Elsevier Ltd. All rights reserved.
Article history: Received 12 December 2016 Accepted 14 December 2016 Available online xxxx Keywords: Jet fuel Arctic diesel fuel Middle distillate fraction Isodewaxing Isodewaxing catalyst
1. Introduction Fuels for operation at low ambient temperatures are strategically important products. Widespread demand is characteristic for jet fuel and, especially in the regions located in Arctic and Subarctic climatic zones, for diesel fuel with improved cold flow properties (regions of Russia, countries of Northern Europe,
⇑ Corresponding author. E-mail addresses: (A.I. Grudanova).
[email protected],
[email protected]
Canada). Development of technologies for production of these fuels is a relevant issue of oil industry. To achieve this purpose the most effective is isodewaxing process, which enable to obtain fuels with improved cold flow properties at high yield. When isodewaxing are applied long-chain n-alkanes in the fuel composition are subjected to isomerization with formation of iso-alkanes with cold flow characteristics better then inherent to n-alkanes. VNII NP JSC developed technology based on own non-noble metal catalyst for production jet fuel and arctic diesel fuel from waxy middle distillate oil and Fischer-Tropsch fractions.
http://dx.doi.org/10.1016/j.fuel.2016.12.032 0016-2361/Ó 2016 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Grudanova AI et al. Jet fuel and arctic diesel fuel production by isodewaxing of waxy middle distillate fractions. Fuel (2016), http://dx.doi.org/10.1016/j.fuel.2016.12.032
2
A.I. Grudanova et al. / Fuel xxx (2016) xxx–xxx
2. Materials and methods Generation of jet fuel and diesel fuel was carried out in the isodewaxing process over the catalyst developed by VNII NP JSC with general composition NiMo/ZSM-11/mordenite. The feedstock for isodewaxing was middle distillate fraction 140–350 °C, obtained by hydroforming over AlCoMo catalyst of mixture of synthetic oil fraction 140–350 °C and straight-run diesel fraction 180–350 °C (volume ratio 30/70). The feedstock is characterized by the density at 15 °C 817.4 kg/m3; sulfur content of 8 ppm; cloud point of 6 °C, pour point of 10 °C, cold filter plugin point (CFPP) of 7 °C. The main position of distillation: distilled up to 180 °C 9.7% vol., 95% vol. distilled at 342 °C. The content of fraction C12+ is 85.8% wt. and content of n-alkanes is 48.9% wt. Evaluation of the aviation kerosene quality was conducted in accordance with methods, which are set by ASTM D16551 and Russian standard GOST 10227-20132. Diesel fuel quality was evaluated by methods listed in EN 590:20093 and Russian standard GOST R 55475-20134. It includes practically all parameters of EN 590:2009, though it considers the fact that with reduction of n-alkanes content during dewaxing processes the concentration of cycloalkanes and aromatics enhances, which results in density increase. The density norm of GOST R 55475-2013 is 800–855 kg/m3 while the norm of EN 590:2009 is 800–840 kg/m3. Study of group composition of jet fuel and diesel fuel was performed by gas chromatography and gas chromatography/mass spectrometry measurements, respectively.
3. Theory For effective isodewaxing process, it is important not only to find out an optimal catalyst, but also to determine the optimal operation conditions. Low temperatures (300–330 °C) and middle pressure level (3–4 MPa) favor to effective long-chain n-alkanes isomerization reaction. Increased ratio H2/feed (min 400 m3/m3) and increased LHSV (min 2 h 1) provide the suppression of the coke formation and cracking of intermediate compounds.
Table 1 Quality of the feed fraction 135–230 °C and jet fuel (135–230 °C) produced in the isodewaxing process. Indicator
Actual value
The norm according to GOST 10227-2013 for RT brand
Feed fraction
Jet fuel
Density at 20 °C (kg/m3)
765
784
min 775
Distillation (°C): Initial boiling point (IBP) 10% (vol.) distilled at 50% (vol.) distilled at 90% (vol.) distilled at 98% (vol.) distilled at Residue from distillation (% vol.)
135 147 179 223 265 1.4
135 143 176 223 261 1.3
135–155 max 175 max 225 max 270 max 280 max 1.5
Lowest heat of combustion (kJ/kg) Chilling point (°C) Smoke point (mm) Aromatics content (% vol.)
43,390 20 40 13
43,133 < 62 36 17.6
min 43,120 max 60 min 25 max 22
Table 2 Quality of the feed fraction 180–350 °C and arctic diesel (180–350 °C) produced in the isodewaxing process. Indicator
Feed fraction
Actual value Arctic diesel fuel
The norm according to GOST R 55475-2013 for arctic diesel of DT-A minus 44 brand
Cetane number Cetane index Density at 15 °C (kg/m3) Polycyclic aromatics content (% wt.) Sulfur content (ppm) The flash point in closed crucible (°C)
49.9 46.1 824.7 3.3 9.0 58
49.2 45.2 846.7 3.9 4.0 62
min 47.0 min 43.0 800.0–855.0 max 8.0 max 10.0 min 30
Distillation: Distilled up to 180 °C (% vol.) 95% (vol.) distilled at (°C) Cloud point (°C) CFPP (°C)
3.3 343 6 7
7.5 339 N/Ca 49
max 10 max 360 max 34 max 44
a N/A – no cloudiness (no precipitation of paraffin crystals in sight of the equipment ( 72 °C)).
4. Results and discussion At pilot scale tests it was established the optimal isodewaxing conditions for production of target fuels: 300 °C, 3.0 MPa, LHSV 3.1 h 1 and H2/feed ratio 600 m3/m3. Tests were carried out in the system with circulating of hydrogen rich gas. Catalytic system includes besides the major isodewaxing catalyst (65 cm3) conventional industrial hydrotreating catalyst (HDT). The HDT catalyst was loaded in the reactor top (5 cm3) to protect the main catalyst against impurities in the feedstock, and the HDT catalyst was loaded in the reactor bottom (30 cm3) – to ensure hydrofinishing function, i.e. hydrogenation of unsaturated compounds resulting from side cracking reactions of feed and products. Before experiment, the catalyst was dried and was sulfided to transfer metal oxides in catalytically active forms NiS and Mo2S3. During process tests for 170 h it was accumulated about 15 l of hydrogenate (liquid reaction product) with pour point not higher than 72 °C below zero. Middle distillate fractions from hydrogenate was separated in accordance with two options: 1
GOST 10227-2013 Fuel for jet engines. Specifications. ASTM D1655 Standard Specification for Aviation Turbine Fuels. 3 EN 590:2009 + F1:2010 Automotive fuels – Diesel – Requirements and test methods. 4 GOST R 55475-2013 Dewaxed winter and Arctic diesel fuel. Specifications. 2
(1) Concurrent obtaining of kerosene fraction 135–230 °C (23.2% wt. feed rate) and heavy diesel fraction 230–350 °C (68.8% wt. feed rate) at total yield 92% wt. (2) Variable (seasonal) obtaining of kerosene fraction 135– 230 °C (23.2% wt. feed rate) and diesel fraction 180–350 °C (77.9% wt. feed rate). It was established the kerosene fraction 135–230 °C meets to jet fuel; diesel fraction 180–350 °C meets to arctic diesel. Target products main quality indicators are provided in Tables 1 and 2. We can see the depression of chilling point and CFPP more than 42 ° in obtained jet fuel and diesel fuel compared to corresponding feed fractions with the same distillation. Obtained products characteristics meet to requirements of the regulation documents. Heavy diesel fraction 230–350 °C obtained in option 1 cannot be used as arctic diesel because of the lack of light hydrocarbons in its composition, but its quality meets to requirement for winter diesel with CFPP not higher than 38 °C below zero. For target arctic diesel and jet fuel, the content of iso-alkanes is 40.36 and 38.45% wt., respectively. It was provided to achieve the large depression values of CFPP and chilling point (42 °). Use of the developed isodewaxing catalyst under optimal conditions enables to reduce the cracking reactions extent and, consequently, to produce middle motor fuels with improved cold flow properties at high yield (total yield 92% wt.).
Please cite this article in press as: Grudanova AI et al. Jet fuel and arctic diesel fuel production by isodewaxing of waxy middle distillate fractions. Fuel (2016), http://dx.doi.org/10.1016/j.fuel.2016.12.032
A.I. Grudanova et al. / Fuel xxx (2016) xxx–xxx
5. Conclusion It can be concluded the new isodewaxing process over non-noble metal catalyst developed by VNII NP JSC is effective to convert waxy feedstock into strategically important products at high yield – jet fuel and diesel fuel for Arctic service. Stable indicators of technology operation were confirmed in pilot scale during 170 h of continuous tests. Carried out researches serve as a basis
3
for design the technology documentation for unit with increased catalysts loading. Funding This work was supported by the Ministry of Education and Science of Russian Federation [Grant No. 14.579.21.0061; grant unique identifier RFMEFI57914X0061].
Please cite this article in press as: Grudanova AI et al. Jet fuel and arctic diesel fuel production by isodewaxing of waxy middle distillate fractions. Fuel (2016), http://dx.doi.org/10.1016/j.fuel.2016.12.032
Contents lists available at ScienceDirect
Fuel journal homepage: www.elsevier.com/locate/fuel
Letter to the editor
Jet fuel and arctic diesel fuel production by isodewaxing of waxy middle distillate fractions Alena I. Grudanova ⇑, Ludmila A. Gulyaeva, Ludmila A. Krasilnikova, Olga I. Shmelkova, Roman E. Boldushevskii All-Russia Research Institute of Oil Refining JSC (VNII NP JSC), Aviamotornaya St. 6, Moscow 111116, Russia
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
Isodewaxing process for production
motor fuel with improved cold flow properties. The isodewaxing process can be used to expand the feedstock base for motor fuels production. Isodewaxing process produce jet fuel with chilling point < 62 °C. Isodewaxing process produce arctic diesel fuel with cold filter plugin point 49 °C. Total yield of motor fuels for operation at low ambient temperatures is 92% wt.
a r t i c l e
i n f o
a b s t r a c t Jet fuel with chilling point not higher than 60 °C below zero and arctic diesel fuel with cold filter plugin point not higher than 44 °C below zero are produced in the isodewaxing process developed by VNII NP JSC based on non-noble metal catalyst (NiMo/ZSM-11/mordenite). Resulting in pilot scale tests with isodewaxing catalyst load 65 cm3 during 170 h possibility of stable production of fuels met to regulation documents requirement was established. Study of group composition of target fuels shown the achievement of cold flow properties improvement is provided by the predominance in the fuels composition isoalkanes obtained during isodewaxing process. Ó 2016 Elsevier Ltd. All rights reserved.
Article history: Received 12 December 2016 Accepted 14 December 2016 Available online xxxx Keywords: Jet fuel Arctic diesel fuel Middle distillate fraction Isodewaxing Isodewaxing catalyst
1. Introduction Fuels for operation at low ambient temperatures are strategically important products. Widespread demand is characteristic for jet fuel and, especially in the regions located in Arctic and Subarctic climatic zones, for diesel fuel with improved cold flow properties (regions of Russia, countries of Northern Europe,
⇑ Corresponding author. E-mail addresses: (A.I. Grudanova).
[email protected],
[email protected]
Canada). Development of technologies for production of these fuels is a relevant issue of oil industry. To achieve this purpose the most effective is isodewaxing process, which enable to obtain fuels with improved cold flow properties at high yield. When isodewaxing are applied long-chain n-alkanes in the fuel composition are subjected to isomerization with formation of iso-alkanes with cold flow characteristics better then inherent to n-alkanes. VNII NP JSC developed technology based on own non-noble metal catalyst for production jet fuel and arctic diesel fuel from waxy middle distillate oil and Fischer-Tropsch fractions.
http://dx.doi.org/10.1016/j.fuel.2016.12.032 0016-2361/Ó 2016 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Grudanova AI et al. Jet fuel and arctic diesel fuel production by isodewaxing of waxy middle distillate fractions. Fuel (2016), http://dx.doi.org/10.1016/j.fuel.2016.12.032
2
A.I. Grudanova et al. / Fuel xxx (2016) xxx–xxx
2. Materials and methods Generation of jet fuel and diesel fuel was carried out in the isodewaxing process over the catalyst developed by VNII NP JSC with general composition NiMo/ZSM-11/mordenite. The feedstock for isodewaxing was middle distillate fraction 140–350 °C, obtained by hydroforming over AlCoMo catalyst of mixture of synthetic oil fraction 140–350 °C and straight-run diesel fraction 180–350 °C (volume ratio 30/70). The feedstock is characterized by the density at 15 °C 817.4 kg/m3; sulfur content of 8 ppm; cloud point of 6 °C, pour point of 10 °C, cold filter plugin point (CFPP) of 7 °C. The main position of distillation: distilled up to 180 °C 9.7% vol., 95% vol. distilled at 342 °C. The content of fraction C12+ is 85.8% wt. and content of n-alkanes is 48.9% wt. Evaluation of the aviation kerosene quality was conducted in accordance with methods, which are set by ASTM D16551 and Russian standard GOST 10227-20132. Diesel fuel quality was evaluated by methods listed in EN 590:20093 and Russian standard GOST R 55475-20134. It includes practically all parameters of EN 590:2009, though it considers the fact that with reduction of n-alkanes content during dewaxing processes the concentration of cycloalkanes and aromatics enhances, which results in density increase. The density norm of GOST R 55475-2013 is 800–855 kg/m3 while the norm of EN 590:2009 is 800–840 kg/m3. Study of group composition of jet fuel and diesel fuel was performed by gas chromatography and gas chromatography/mass spectrometry measurements, respectively.
3. Theory For effective isodewaxing process, it is important not only to find out an optimal catalyst, but also to determine the optimal operation conditions. Low temperatures (300–330 °C) and middle pressure level (3–4 MPa) favor to effective long-chain n-alkanes isomerization reaction. Increased ratio H2/feed (min 400 m3/m3) and increased LHSV (min 2 h 1) provide the suppression of the coke formation and cracking of intermediate compounds.
Table 1 Quality of the feed fraction 135–230 °C and jet fuel (135–230 °C) produced in the isodewaxing process. Indicator
Actual value
The norm according to GOST 10227-2013 for RT brand
Feed fraction
Jet fuel
Density at 20 °C (kg/m3)
765
784
min 775
Distillation (°C): Initial boiling point (IBP) 10% (vol.) distilled at 50% (vol.) distilled at 90% (vol.) distilled at 98% (vol.) distilled at Residue from distillation (% vol.)
135 147 179 223 265 1.4
135 143 176 223 261 1.3
135–155 max 175 max 225 max 270 max 280 max 1.5
Lowest heat of combustion (kJ/kg) Chilling point (°C) Smoke point (mm) Aromatics content (% vol.)
43,390 20 40 13
43,133 < 62 36 17.6
min 43,120 max 60 min 25 max 22
Table 2 Quality of the feed fraction 180–350 °C and arctic diesel (180–350 °C) produced in the isodewaxing process. Indicator
Feed fraction
Actual value Arctic diesel fuel
The norm according to GOST R 55475-2013 for arctic diesel of DT-A minus 44 brand
Cetane number Cetane index Density at 15 °C (kg/m3) Polycyclic aromatics content (% wt.) Sulfur content (ppm) The flash point in closed crucible (°C)
49.9 46.1 824.7 3.3 9.0 58
49.2 45.2 846.7 3.9 4.0 62
min 47.0 min 43.0 800.0–855.0 max 8.0 max 10.0 min 30
Distillation: Distilled up to 180 °C (% vol.) 95% (vol.) distilled at (°C) Cloud point (°C) CFPP (°C)
3.3 343 6 7
7.5 339 N/Ca 49
max 10 max 360 max 34 max 44
a N/A – no cloudiness (no precipitation of paraffin crystals in sight of the equipment ( 72 °C)).
4. Results and discussion At pilot scale tests it was established the optimal isodewaxing conditions for production of target fuels: 300 °C, 3.0 MPa, LHSV 3.1 h 1 and H2/feed ratio 600 m3/m3. Tests were carried out in the system with circulating of hydrogen rich gas. Catalytic system includes besides the major isodewaxing catalyst (65 cm3) conventional industrial hydrotreating catalyst (HDT). The HDT catalyst was loaded in the reactor top (5 cm3) to protect the main catalyst against impurities in the feedstock, and the HDT catalyst was loaded in the reactor bottom (30 cm3) – to ensure hydrofinishing function, i.e. hydrogenation of unsaturated compounds resulting from side cracking reactions of feed and products. Before experiment, the catalyst was dried and was sulfided to transfer metal oxides in catalytically active forms NiS and Mo2S3. During process tests for 170 h it was accumulated about 15 l of hydrogenate (liquid reaction product) with pour point not higher than 72 °C below zero. Middle distillate fractions from hydrogenate was separated in accordance with two options: 1
GOST 10227-2013 Fuel for jet engines. Specifications. ASTM D1655 Standard Specification for Aviation Turbine Fuels. 3 EN 590:2009 + F1:2010 Automotive fuels – Diesel – Requirements and test methods. 4 GOST R 55475-2013 Dewaxed winter and Arctic diesel fuel. Specifications. 2
(1) Concurrent obtaining of kerosene fraction 135–230 °C (23.2% wt. feed rate) and heavy diesel fraction 230–350 °C (68.8% wt. feed rate) at total yield 92% wt. (2) Variable (seasonal) obtaining of kerosene fraction 135– 230 °C (23.2% wt. feed rate) and diesel fraction 180–350 °C (77.9% wt. feed rate). It was established the kerosene fraction 135–230 °C meets to jet fuel; diesel fraction 180–350 °C meets to arctic diesel. Target products main quality indicators are provided in Tables 1 and 2. We can see the depression of chilling point and CFPP more than 42 ° in obtained jet fuel and diesel fuel compared to corresponding feed fractions with the same distillation. Obtained products characteristics meet to requirements of the regulation documents. Heavy diesel fraction 230–350 °C obtained in option 1 cannot be used as arctic diesel because of the lack of light hydrocarbons in its composition, but its quality meets to requirement for winter diesel with CFPP not higher than 38 °C below zero. For target arctic diesel and jet fuel, the content of iso-alkanes is 40.36 and 38.45% wt., respectively. It was provided to achieve the large depression values of CFPP and chilling point (42 °). Use of the developed isodewaxing catalyst under optimal conditions enables to reduce the cracking reactions extent and, consequently, to produce middle motor fuels with improved cold flow properties at high yield (total yield 92% wt.).
Please cite this article in press as: Grudanova AI et al. Jet fuel and arctic diesel fuel production by isodewaxing of waxy middle distillate fractions. Fuel (2016), http://dx.doi.org/10.1016/j.fuel.2016.12.032
A.I. Grudanova et al. / Fuel xxx (2016) xxx–xxx
5. Conclusion It can be concluded the new isodewaxing process over non-noble metal catalyst developed by VNII NP JSC is effective to convert waxy feedstock into strategically important products at high yield – jet fuel and diesel fuel for Arctic service. Stable indicators of technology operation were confirmed in pilot scale during 170 h of continuous tests. Carried out researches serve as a basis
3
for design the technology documentation for unit with increased catalysts loading. Funding This work was supported by the Ministry of Education and Science of Russian Federation [Grant No. 14.579.21.0061; grant unique identifier RFMEFI57914X0061].
Please cite this article in press as: Grudanova AI et al. Jet fuel and arctic diesel fuel production by isodewaxing of waxy middle distillate fractions. Fuel (2016), http://dx.doi.org/10.1016/j.fuel.2016.12.032