Title of Invention	AN IMPROVED PROCESSS FOR EXTRACTION OF AROMATIC HYDROCARBONS FROM KEROSENE RANGE USING MICROPOROUS HOLLOW FIBRE MEMBRANES
Abstract	The present invention provides an improved process for the extraction of aromatic hydrocarbons from kerosene range and the said process comprising pumping the feed mixture containing kerosene range aromatics and non aromatics selected from 1-methyl naphthalene, dodecane and straight run kerosene having a boilng range of 135-240, in the concentration range of 15 to 40% wt. at a pressure 1 to 10 psi through the lumen of the microporous hollow fiber membrane contactor while the solvent is pumped through the shell side in a counter current mode at slightly higher pressure allowing the contact of both the phases for a time of 1 to 5 mins at a temperature ranging 25-400c, collecting the aromatic rich solvent (extract phase) and aromatic lean kerosene range hydrocarbons (raffinate phase) separately by the two ends of the said hollow fibre membrane. This process is useful in petroleum industry for production of aviation grade Kerosene and illuminant grade Kerosene.

Title of Invention

AN IMPROVED PROCESSS FOR EXTRACTION OF AROMATIC HYDROCARBONS FROM KEROSENE RANGE USING MICROPOROUS HOLLOW FIBRE MEMBRANES

Abstract

The present invention provides an improved process for the extraction of aromatic hydrocarbons from kerosene range and the said process comprising pumping the feed mixture containing kerosene range aromatics and non aromatics selected from 1-methyl naphthalene, dodecane and straight run kerosene having a boilng range of 135-240, in the concentration range of 15 to 40% wt. at a pressure 1 to 10 psi through the lumen of the microporous hollow fiber membrane contactor while the solvent is pumped through the shell side in a counter current mode at slightly higher pressure allowing the contact of both the phases for a time of 1 to 5 mins at a temperature ranging 25-400c, collecting the aromatic rich solvent (extract phase) and aromatic lean kerosene range hydrocarbons (raffinate phase) separately by the two ends of the said hollow fibre membrane. This process is useful in petroleum industry for production of aviation grade Kerosene and illuminant grade Kerosene.

Full Text	This invention relates to an improved process for the extraction of aromatic hydrocarbons from mixtures containing such hydrocarbons and nonaromatics using a microporous hollow fibre membrane contactor. The extraction of aromatics from mixtures with non-aromatics is an important unit operation in the petroleum industry. The_ straight Run kerosene (S.R.) from say Bombay High and Assam crude oils contain26% to 33% wt. aromatics and these kerosenes have to be dearomatized to produce aviation grade kerosene/ superior illuminant grade kerosene containing The existing technology for selective aromatic removal from S.R. kerosene to produce aviation grade/superior illuminant grade kerosene utilizes liquid-liquid extraction with polar solvents such as liquid sulphur dioxide (as in the Edeleanu Process), sulpholane,and mono,di-, tri-, and tetraethylene glycols. The extraction is done by bringing the feed mixtures to be separated into intimate contact with the solvent in conventional extraction equipments like mixer -settler, packed and sieve tray columns. The solvent gets loaded with the components (aromatics) that have to be removed. There are however, several disadvantages of this process. 1- Some of the extraction solvents that are selective for this extraction (sulpholane, tri-ethylene glycol generally have boiling points overlapping with S.R. kerosene so 4- that solvent recovery becomes difficult. 2- While an extraction solvent like liquid S02 does not have boiling point overlap with kerosene there is however a serious problem of corrosion in liquid SC>2 - based kerosene extraction plants. 3- The extraction equipment used (like sieve tray columns) is generally not verv efficient and sieve tray efficiencies higher than 20% are difficult to achieve in practice. On the other hand use of agitated columns with higher efficiencies leads to conditions of high shear which cause flooding and phase settling problems especially in low interfacial tension systems involving kerosene and polar extraction solvent. Independent variation of phase flow rates is not at all possible as column flooding occurs. It is known that apart from liquid sulphur-dioxide there are other low- boiling polar solvents (like Acetonitrile for example) which can selectively extract aromatics from kerosene. Use of such solvents in kerosene extraction would solve the problem of solvent recovery after the extraction step as boiling points of the solvent will be sufficiently different from S.R.Kerosene. However such solvents will have a low density difference with kerosene and in the existing extraction equipment (like sieve tray columns or agitated columns) the operation will not be stable and phase disengagement becomes difficult. It is known that liquid-liquid extraction can be carried out efficiently under conditions of low shear and low density difference between contacting feed and solvent phases by using microporous hollow fibre membrane modular devices in a shell-tube configuration. Here the feed may be passed through the lumen of the fibers while the solvent is passed through the shell side of the module. The interface between feed and solvent phases is maintained at the rnicropores in the fiber walls. This method of contact has the advantage of high mass transfer efficiency because of high transfer area available while maintaining low shear conditions, unlike conventional extractors. No problems of phase disengagement are encountered and phase flow rates can be independently varied. The main object of the present invention is to provide a process for the extraction of aromatics hydrocarbons from mixtures with nonaromatics boiling upto the range of kerosene by liquid-liquid extraction using low-boiling polar solvent such as acetonitrile in a nondispersive way in a microporous hollow fiber membrane contactor. This invention is based on the finding that to overcome the problems associated with high-boiling selective solvents with regard to solvent recovery in the extraction of kerosene range aromatics from nonaromatics, a low-boiling selective solvent like acetonitrile may be used and the extraction can be carried out in a microporous hollow fiber membrane contactor in place of typical conventional extractors like sieve plate columns, agitated columns so that no flooding/phase disengagement problems are encountered with the low-boiling solvent. Such phase settling problems prevent efficient extraction of aromatics from kerosene with low-boiling solvents in conventional extractors. The extraction of aromatic hydrocarbons from mixtures of aromatics and non-aromataics can be carried out in microporous polypropylene hollow fiber membrane contactor depicted in Fig-1 of the drawing accompanying this specification. Accordingly, the present invention provides an improved process for the extraction of aromatic hydrocarbons from kerosene range and the said process comprising pumping the feed mixture containing kerosene range aromatics and non aromatics selected from 1-methyl naphthalene, dodecane and straight run kerosene having a boilng range of 135-240, in the concentration range of 15 to 40% wt. at a pressure 1 to 10 psi through the lumen of the microporous hollow fiber membrane contactor while the solvent is pumped through the shell side in a counter current mode at slightly higher pressure allowing the contact of both the phases for a time of 1 to 5 mins at a temperature ranging 25-400c, collecting the aromatic rich solvent (extract phase) and aromatic lean kerosene range hydrocarbons (raffmate phase) separately by the two ends of the said hollow fibre membrane. The aromatic hydrocarbon molecules diffuse through the pores in the fiber walls from the feed mixture into the solvent phase present in the shell side.The aromatic-lean feed is withdrawn from one end while the aromatic-rich solvent is withdrawn from the other end. The loaded solvent is sent to a distillation unit for aromatic recovery. The operation is at ambient temperature. The said process for the extraction of aromatic hydrocarbons from mixtures containing such hydrocarbons and non-aromatics in the kerosene range can be carried out according to the following steps. 1- Pumping the feed mixture with a metering pump under pressure control at a specified rate through the tube side of a microporous polypropylene hollow fiber membrane contactor. 2- Pumping the solvent with a metering pump under pressure control at a specified rate through the shell side of the same microporous hollow fiber membrane contactor. 3- Controlling the flow rates and fluid pressure conditions of the two phases so that a pressure differential of around 2.0 psi is maintained between the feed phase and the solvent phase in the contactor, with the solvent being at the higher pressure. 4- Allowing sufficient time of 30-40 mins to elapse so that steady state conditions are attained. 5- Collecting the aromatic-lean (raffinate) phase and the aromatic-rich solvent (extract) phase separately. The details of the above mentioned steps may be varied as follows. 1- The solvent may be pumped through the shell side of the microporous hollow fiber membrane contactor and the feed may be pumped through the lumen of the microporous hollow fibers. Alternatively the solvent may be pumped through the lumen of the microporous hollow fibres while the feed is pumped on the shell side of the hollow fibres. 2- The flow rate of the solvent may be varied from 5 ml/min to 20 ml/min and the pressure can be maintained between 4-6 psi. 3- The flow rate of the feed can be varied from 5 ml to 15 ml/min and pressure maintained between 2 and 5 psi 4- The hydrocarbon feed mixture may be a model mixture (1-methylnaphthalene and dodecane) or an actual S.R. kerosene. 5- The temperature may range from 25-40 °C. 6- The aromatic content in the feed mixture may vary from 20-35 vol%. The extraction of aromatic hydrocarbons from mixtures of kerosene range aromatics and nonaromatics can be carried out in a microporous hollow fiber membrane contactor/depicted in Fig-1 of the drawing accompanying^this specification This contactor has 3600 microporous polypropylene hollow fibers of length 30 m. O.D. 210 microns, ID. 180 microns and average wall pore size 0.05 microns. The fibers are potted with epoxy resin in a glass tube to give a module of a shell-tube configuration . To start the process, feed mixture and solvent is pumped from reservoir Rl and R2 respectively.The solvent is pumped through Line 3 by metering pump P2 to enter the microporous hollow fiber contactor MHF through the shell side. The solvent input flow rate is measured by the flow measuring burette B2. The loaded solvent exits the contactor through the Line 4 under pressure control valve NV1, with flow rate monitored by flow meter FM1. The solvent phase inlet and outlet pressures are monitored by pressure gauges PG3 and PG2 respectively and these are maintained at around 5 to 6 psrwith a pressure drop of around 0.2 psi. Feed from reservoir Rl is then pumped by metering pump PI through Line 1 to enter the microporous hollow fiber membrane contactor MHF through the tube side. Feed input flow rate is measured by the flow measuring burette Bl and monitored by flow meter FM2. Feed pressure at entry and exit point is recorded in pressure gauges PG1 and Pg 4. .The dearomatized or lean feed exits the contactor through Line 2 under pressure control of valve NV2. Pumping of streams is continued for about 30 to 45 mins. Samples of aromatic-lean kerosene range hydrocarbons (raffinate phase) and aromatic rich solvent (extract phase) are collected from Line 2 and Line 4 respectively. The solvent phase (extract) may be distilled to recover the aromatic rich product and the aromatic-lean kerosene range hydrocarbon phase analysed for determining the aromatic content. This invention is further illlustrated by the following examples, which should not be construed to limit the scope of the invention. Example 1- This example describes the extraction of 1-methyl naphthalene (1-MeN) from a synthetic feed mixture containing 23%wt 1-methyl naphthalene and 77%wt dodecane by solvent acetonitrile in a microporous hollow fibre membrane contactor. In this example, feed mixture was taken in feed reservoir and pumped through the tube side of the microporous hollow fiber membrane contactor at 6 ml/min flow rate and the tube side inlet and outlet pressures were maintained at 3.0 and 2.5 psi respectively . The solvent, acetonitrile was taken in the solvent reservoir and pumped through the shell side of the hollow fiber contactor at 6 ml/min . The shell side inlet and outlet pressures were maintained at 4.6 and 4.5 psi respectively. Pumping of the fluids through the contactor was continued for 60 minutes . During this time, samples of treated feed or raffinate coming out of the contactor were collected at 20, 30, and 50 mins. The raffinate phase was analysed by refractive index method to determine the concentration of 1-methyl naphthalene. The percentage removal of the aromatic (1-methyl naphthalene) was calculated as % 1- MeN Removal = 1 -MeN in feed - 1 -MeN in Raffinate Phase 1 Men in feed In this particular example 1-MeN concentration in the raffinate collected at 20,30 and 50 minutes were 12.64,12.64, and 12.31%wt. respectively . The average 1-methylnaphthalene percentage removal at steady state was therefore 45.5. Example 2- This example describes the extraction of 1- methylnaphtalene from a synthetic feed mixture containing 24 wt% 1-methyl naphthalene and 76 wt% dodecane by acetonitrile solvent in a microporous hollow fiber membrane contactor as in example 1 but at higher flow rate of solvent phase. The solvent phase was pumped into the shell side of the hollow fiber membrane contactor at 14 ml/min with the inlet and outlet pressures maintained at 3.75 and 4.0 psi respectively. The feed phase was pumped into the tube side at flow rate of 6 ml/min and the tube side inlet and outlet pressure were maintained at 5.0 psi. In this particular example 1-methylnaphthalene concentration in the raffinate at 20,30, and 50 minutes were 7.97%, 5.99% and 8.0%wt respectively. The average percentage removal was therefore 69.5%. Example 3- This example describes the extraction of aromatic hydrocarbons from an actual S.R.Kerosene of boiling range 140-240 °C from Assam crude oil containing 35 vol% aromatics in microporous hollow fiber membrane contactor by Acetonitrile as solvent as in previous examples. Feed mixture was pumped through the tube side at 12 ml/min flow rate with the inlet and outlet pressures of 5.0 psi. The solvent phase was pumped into the shell side at flow rate of 20 ml/min and the tube side inlet and outlet pressures were maintained at 5.0 and 4.5 psi respectively. In this particular example aromatic content in the raffinate phase was 33 vol% after 40 min and % removal was 5.7. Main advantage of the present invention : The extraction of aromatics from nonaromatics in kerosene range is being done by solvent extraction in conventional equipments like sieve tray, packed column and/or mixer settlers. Such liquid-liquid extraction requires high-boiling solvents to avoid problems of flooding and phase disengagement of phases. However, use of such high-boiling solvents gives problems of solvent recovery due to overlapping of boiling points of solvent and feed mixtures. The main advantage of the present invention is that it provides an improved process which allows using low-boiling solvent like acetonitrile . Such a low- boiling solvent makes solvent recovery easier from the extract phase. It also provides an improved method of contacting of phases in a nondispersive way so that no flooding/phase disengagement problems are encountered with low-boiling solvent. We Claim: 1. An improved process for the extraction of aromatic hydrocarbons from kerosene range and the said process comprising pumping the feed mixture containing kerosene range aromatics and non aromatic s selected from 1-methyl naphthalene, dodecane and straight Run Kerosene having aboilng range of 135- 240, in the concentration range of 15 to 40% wt. at a pressure 1 to 10 psi through the lumen of the microporous hollow fiber membrane contactor while the solvent is pumped through the shell side in a counter current mode at slightly higher pressure allowing the contact of both the phases for a time of 1 to 5 mins at a temperature ranging 25-40°C, collecting the aromatic rich solvent (extract phase) and aromatic lean kerosene range hydrocarbons (raffinate phase) separately by the two ends of the said hollow fibre membrane. 2. An improved process as claimed in Claim 1 to 2, wherein the feed mixture contains aromatics in the range of 20 - 35 wt. %. 3. An improved process as claimed in claim 1 to 2, wherein the feed mixture is pumped at pressure 1-10 psi at flow rates preferably in the range of 6 to 12 ml/min and solvent is pumped at flow rates preferably in the range of 6 to 20 ml/min. 4. An improved process as claimed in claim 1 to 3, wherein the pressure differential between fluid phase pressures in the contactor is about 2.0 psi. 5. An improved process for the extraction of aromatic hydrocarbon from kerosene range substantially as herein described with reference to the examples accompanying this specification.

Full Text

This invention relates to an improved process for the extraction of aromatic hydrocarbons from mixtures containing such hydrocarbons and nonaromatics using a microporous hollow fibre membrane contactor. The extraction of aromatics from mixtures with non-aromatics is an important unit operation in the petroleum industry. The_ straight Run kerosene (S.R.) from say Bombay High and Assam crude oils contain26% to 33% wt. aromatics and these kerosenes have to be dearomatized to produce aviation grade kerosene/ superior illuminant grade kerosene containing The existing technology for selective aromatic removal from S.R. kerosene to produce aviation grade/superior illuminant grade kerosene utilizes liquid-liquid extraction with polar solvents such as liquid sulphur dioxide (as in the Edeleanu Process), sulpholane,and mono,di-, tri-, and tetraethylene glycols. The extraction is done by bringing the feed mixtures to be separated into intimate contact with the solvent in conventional extraction equipments like mixer -settler, packed and sieve tray columns. The solvent gets loaded with the components (aromatics) that have to be removed. There are however, several disadvantages of this process.
1- Some of the extraction solvents that are selective for this extraction (sulpholane,
tri-ethylene glycol generally have boiling points overlapping with S.R. kerosene so
4-
that solvent recovery becomes difficult.
2- While an extraction solvent like liquid S02 does not have boiling point overlap
with kerosene there is however a serious problem of corrosion in liquid SC>2 -
based kerosene extraction plants.
3- The extraction equipment used (like sieve tray columns) is generally not verv
efficient and sieve tray efficiencies higher than 20% are difficult to achieve in
practice. On the other hand use of agitated columns with higher efficiencies leads to conditions of high shear which cause flooding and phase settling problems especially in low interfacial tension systems involving kerosene and polar extraction solvent. Independent variation of phase flow rates is not at all possible as column flooding occurs.
It is known that apart from liquid sulphur-dioxide there are other low- boiling polar solvents (like Acetonitrile for example) which can selectively extract aromatics from kerosene. Use of such solvents in kerosene extraction would solve the problem of solvent recovery after the extraction step as boiling points of the solvent will be sufficiently different from S.R.Kerosene. However such solvents will have a low density difference with kerosene and in the existing extraction equipment (like sieve tray columns or agitated columns) the operation will not be stable and phase disengagement becomes difficult.
It is known that liquid-liquid extraction can be carried out efficiently under conditions of low shear and low density difference between contacting feed and solvent phases by using microporous hollow fibre membrane modular devices in a shell-tube configuration. Here the feed may be passed through the lumen of the fibers while the solvent is passed through the shell side of the module. The interface between feed and solvent phases is maintained at the rnicropores in the fiber walls. This method of contact has the advantage of high mass transfer efficiency because of high transfer area available while maintaining low shear conditions, unlike conventional extractors. No problems of phase disengagement are encountered and phase flow rates can be independently varied.
The main object of the present invention is to provide a process for the extraction of aromatics hydrocarbons from mixtures with nonaromatics boiling upto the range of kerosene by liquid-liquid extraction using low-boiling polar solvent such as acetonitrile in a nondispersive way in a microporous hollow fiber membrane contactor. This invention is based on the finding that to overcome the problems associated with high-boiling selective solvents with regard to solvent recovery in the extraction of kerosene range aromatics
from nonaromatics, a low-boiling selective solvent like acetonitrile may be used and the extraction can be carried out in a microporous hollow fiber membrane contactor in place of typical conventional extractors like sieve plate columns, agitated columns so that no flooding/phase disengagement problems are encountered with the low-boiling solvent. Such phase settling problems prevent efficient extraction of aromatics from kerosene with low-boiling solvents in conventional extractors.
The extraction of aromatic hydrocarbons from mixtures of aromatics and non-aromataics can be carried out in microporous polypropylene hollow fiber membrane contactor depicted in Fig-1 of the drawing accompanying this specification. Accordingly, the present invention provides an improved process for the extraction of aromatic hydrocarbons from kerosene range and the said process comprising pumping the feed mixture containing kerosene range aromatics and non aromatics selected from 1-methyl naphthalene, dodecane and straight run kerosene having a boilng range of 135-240, in the concentration range of 15 to 40% wt. at a pressure 1 to 10 psi through the lumen of the microporous hollow fiber membrane contactor while the solvent is pumped through the shell side in a counter current mode at slightly higher pressure allowing the contact of both the phases for a time of 1 to 5 mins at a temperature ranging 25-400c, collecting the aromatic rich solvent (extract phase) and aromatic lean kerosene range hydrocarbons (raffmate phase) separately by the two ends of the said hollow fibre membrane.
The aromatic hydrocarbon molecules diffuse through the pores in the fiber walls from the feed mixture into the solvent phase present in the shell side.The aromatic-lean feed is withdrawn from one end while the aromatic-rich solvent is withdrawn from the other end. The loaded solvent is sent to a distillation unit for aromatic recovery. The operation is at ambient temperature.
The said process for the extraction of aromatic hydrocarbons from mixtures containing such hydrocarbons and non-aromatics in the kerosene range can be carried out according to the following steps.
1- Pumping the feed mixture with a metering pump under pressure control at a
specified rate through the tube side of a microporous polypropylene hollow fiber
membrane contactor.
2- Pumping the solvent with a metering pump under pressure control at a specified
rate through the shell side of the same microporous hollow fiber membrane
contactor.
3- Controlling the flow rates and fluid pressure conditions of the two phases so that a
pressure differential of around 2.0 psi is maintained between the feed phase and the
solvent phase in the contactor, with the solvent being at the higher pressure.
4- Allowing sufficient time of 30-40 mins to elapse so that steady state conditions are
attained.
5- Collecting the aromatic-lean (raffinate) phase and the aromatic-rich solvent
(extract) phase separately.
The details of the above mentioned steps may be varied as follows.
1- The solvent may be pumped through the shell side of the microporous hollow fiber
membrane contactor and the feed may be pumped through the lumen of the
microporous hollow fibers. Alternatively the solvent may be pumped through the
lumen of the microporous hollow fibres while the feed is pumped on the shell side
of the hollow fibres.
2- The flow rate of the solvent may be varied from 5 ml/min to 20 ml/min and the
pressure can be maintained between 4-6 psi.
3- The flow rate of the feed can be varied from 5 ml to 15 ml/min and pressure
maintained between 2 and 5 psi
4- The hydrocarbon feed mixture may be a model mixture (1-methylnaphthalene and
dodecane) or an actual S.R. kerosene.
5- The temperature may range from 25-40 °C.
6- The aromatic content in the feed mixture may vary from 20-35 vol%.
The extraction of aromatic hydrocarbons from mixtures of kerosene range aromatics and nonaromatics can be carried out in a microporous hollow fiber membrane contactor/depicted in Fig-1 of the drawing accompanying^this specification This contactor has 3600 microporous polypropylene hollow fibers of length 30 m. O.D. 210 microns, ID. 180 microns and average wall pore size 0.05 microns. The fibers are potted with epoxy resin in a glass tube to give a module of a shell-tube configuration . To start the process, feed mixture and solvent is pumped from reservoir Rl and R2 respectively.The solvent is pumped through Line 3 by metering pump P2 to enter the microporous hollow fiber contactor MHF through the shell side. The solvent input flow rate is measured by the flow measuring burette B2. The loaded solvent exits the contactor through the Line 4 under pressure control valve NV1, with flow rate monitored by flow meter FM1. The solvent phase inlet and outlet pressures are monitored by pressure gauges PG3 and PG2 respectively and these are maintained at around 5 to 6 psrwith a pressure drop of around 0.2 psi. Feed from reservoir Rl is then pumped by metering pump PI through Line 1 to enter the microporous hollow fiber membrane contactor MHF through the tube side. Feed input flow rate is measured by the flow measuring burette Bl and monitored by flow meter FM2. Feed pressure at entry and exit point is recorded in pressure gauges PG1 and Pg 4. .The dearomatized or lean feed exits the contactor through Line 2 under pressure control of valve NV2. Pumping of streams is continued for about 30 to 45 mins. Samples of aromatic-lean kerosene range hydrocarbons (raffinate phase) and aromatic rich solvent
(extract phase) are collected from Line 2 and Line 4 respectively. The solvent phase (extract) may be distilled to recover the aromatic rich product and the aromatic-lean kerosene range hydrocarbon phase analysed for determining the aromatic content.
This invention is further illlustrated by the following examples, which should not be construed to limit the scope of the invention.
Example 1-
This example describes the extraction of 1-methyl naphthalene (1-MeN) from a synthetic feed mixture containing 23%wt 1-methyl naphthalene and 77%wt dodecane by solvent acetonitrile in a microporous hollow fibre membrane contactor. In this example, feed mixture was taken in feed reservoir and pumped through the tube side of the microporous hollow fiber membrane contactor at 6 ml/min flow rate and the tube side inlet and outlet pressures were maintained at 3.0 and 2.5 psi respectively . The solvent, acetonitrile was taken in the solvent reservoir and pumped through the shell side of the hollow fiber contactor at 6 ml/min . The shell side inlet and outlet pressures were maintained at 4.6 and 4.5 psi respectively. Pumping of the fluids through the contactor was continued for 60 minutes . During this time, samples of treated feed or raffinate coming out of the contactor were collected at 20, 30, and 50 mins.
The raffinate phase was analysed by refractive index method to determine the concentration of 1-methyl naphthalene. The percentage removal of the aromatic (1-methyl naphthalene) was calculated as
% 1- MeN Removal = 1 -MeN in feed - 1 -MeN in Raffinate Phase
1 Men in feed
In this particular example 1-MeN concentration in the raffinate collected at 20,30 and 50 minutes were 12.64,12.64, and 12.31%wt. respectively . The average 1-methylnaphthalene percentage removal at steady state was therefore 45.5.
Example 2-
This example describes the extraction of 1- methylnaphtalene from a synthetic feed mixture containing 24 wt% 1-methyl naphthalene and 76 wt% dodecane by acetonitrile solvent in a microporous hollow fiber membrane contactor as in example 1 but at higher flow rate of solvent phase. The solvent phase was pumped into the shell side of the hollow fiber membrane contactor at 14 ml/min with the inlet and outlet pressures maintained at 3.75 and 4.0 psi respectively. The feed phase was pumped into the tube side at flow rate of 6 ml/min and the tube side inlet and outlet pressure were maintained at 5.0 psi.
In this particular example 1-methylnaphthalene concentration in the raffinate at 20,30, and 50 minutes were 7.97%, 5.99% and 8.0%wt respectively. The average percentage removal was therefore 69.5%.
Example 3-
This example describes the extraction of aromatic hydrocarbons from an actual S.R.Kerosene of boiling range 140-240 °C from Assam crude oil containing 35 vol% aromatics in microporous hollow fiber membrane contactor by Acetonitrile as solvent as in previous examples. Feed mixture was pumped through the tube side at 12 ml/min flow rate with the inlet and outlet pressures of 5.0 psi. The solvent phase was pumped into the shell side at flow rate of 20 ml/min and the tube side inlet and outlet pressures were maintained at 5.0 and 4.5 psi respectively. In this particular example aromatic content in the raffinate phase was 33 vol% after 40 min and % removal was 5.7.
Main advantage of the present invention :
The extraction of aromatics from nonaromatics in kerosene range is being done by solvent extraction in conventional equipments like sieve tray, packed column and/or mixer settlers. Such liquid-liquid extraction requires high-boiling solvents to avoid problems of flooding and phase disengagement of phases. However, use of such high-boiling solvents gives problems of solvent recovery due to overlapping of boiling points of solvent and feed mixtures.
The main advantage of the present invention is that it provides an improved process which allows using low-boiling solvent like acetonitrile . Such a low- boiling solvent makes solvent recovery easier from the extract phase. It also provides an improved method of contacting of phases in a nondispersive way so that no flooding/phase disengagement problems are encountered with low-boiling solvent.

We Claim:
1. An improved process for the extraction of aromatic hydrocarbons from kerosene
range and the said process comprising pumping the feed mixture containing
kerosene range aromatics and non aromatic s selected from 1-methyl
naphthalene, dodecane and straight Run Kerosene having aboilng range of 135-
240, in the concentration range of 15 to 40% wt. at a pressure 1 to 10 psi through
the lumen of the microporous hollow fiber membrane contactor while the solvent
is pumped through the shell side in a counter current mode at slightly higher
pressure allowing the contact of both the phases for a time of 1 to 5 mins at a
temperature ranging 25-40°C, collecting the aromatic rich solvent (extract phase)
and aromatic lean kerosene range hydrocarbons (raffinate phase) separately by the
two ends of the said hollow fibre membrane.
2. An improved process as claimed in Claim 1 to 2, wherein the feed mixture
contains aromatics in the range of 20 - 35 wt. %.
3. An improved process as claimed in claim 1 to 2, wherein the feed mixture is
pumped at pressure 1-10 psi at flow rates preferably in the range of 6 to 12
ml/min and solvent is pumped at flow rates preferably in the range of 6 to 20
ml/min.
4. An improved process as claimed in claim 1 to 3, wherein the pressure differential
between fluid phase pressures in the contactor is about 2.0 psi.
5. An improved process for the extraction of aromatic hydrocarbon from kerosene
range substantially as herein described with reference to the examples
accompanying this specification.

Documents:

1309-del-1998-abstract.pdf

1309-del-1998-claims.pdf

1309-del-1998-correspondence-others.pdf

1309-del-1998-correspondence-po.pdf

1309-del-1998-description (complete).pdf

1309-del-1998-drawings.pdf

1309-del-1998-form-1.pdf

1309-del-1998-form-19.pdf

1309-del-1998-form-2.pdf

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Patent Number

215089

Indian Patent Application Number

1309/DEL/1998

PG Journal Number

10/2008

Publication Date

07-Mar-2008

Grant Date

21-Feb-2008

Date of Filing

15-May-1998

Name of Patentee

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110 001 INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	ANSHU NANOTI	INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005,INDIA
2	AMAR NATH GOSWAMI	INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005,INDIA

PCT International Classification Number

C07C 7/10

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA