Indian Patents. 197730:A SINGLE STEP METHOD FOR REDUCING BENZENE CONTENT OF GASOLINE BELOW 1% BY WEIGHT FOR PARTICULAR USE IN AUTOMOBILES

Title of Invention	A SINGLE STEP METHOD FOR REDUCING BENZENE CONTENT OF GASOLINE BELOW 1% BY WEIGHT FOR PARTICULAR USE IN AUTOMOBILES
Abstract	A single step method for reducing benzene content of gasoline below 1% by weight for particular use in automobiles, comprising the step of treating benzene contaiminated gasoline with water in the weight ratio 1:1 to 3:1 at 25 - 60kg/cm2 pressure and 150 to 260°C and recovering the gasoline from the reaction stream in a known manner.

Full Text	FORM 2 THE PATENTS ACT 1970 (39 of 1970) COMPLETE SPECIFICATION (SEE SECTION 10, Rule 13) TITLE A single step method for reducing benzene content of gasoline below 1% by weight for particular use in automobiles APPLICANTS Larsen & Toubro Limited, L & T House, Ballard Estate, Mumbai - 400001, Maharashtra, India, an Indian company INVENTORS Under Section 28(2) Chittoor Venkatesh Manian, Sanjiv Vasant Save, Dananaickenkottai Venkataramanan Srinivasan and Harshal Balawant Kulkarni, all of Larsen and Toubro Limited, Powai Works, Saki Vihar Road, Mumbai 400072, Maharashtra, India, all Indian nationals The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed : FIELD OF INVENTION This invention relates to a single step method for reducing benzene content of gasoline. Benzene content may be reduced to below 1% by weight for particular use in automobiles. PRIOR ART Carbon monoxide, unburned hydrocarbon, oxides of nitrogen, sulphur dioxide, particulates containing sulfates, benzene or polynuclear aromatics are major pollutants from automobiles. Benzene causes leukemia and could also result in aplstic anemia and immuno and neuro toxicity. Considering the toxicity and carcinogenicity of benzene, emission norms of automobiles run on gasoline (petrol) require that benzene must be converted into benign components and benzene content in the gasoline should be below 1% by weight. Refineries making petrol for automobiles are thus required to ensure benzene content in the petrol below 1% by weight. Several processes for reducing benzene content of gasoline below 1% by weight are reported. Benzene saturation process comprises preheating streams fonning gasoline pool containing benzene with steam followed by mixing with hydrogen and passing the mixture over a bed of noble metal catalyst at elevated temperatures and pressures (US Patent No 5663466A). This process involves multiple steps and uses catalyst which is a consumable item rendering its operating cost high. Preheating by steam requires additional thermal energy. Hydrogen is highly explosive and hazardous and very difficult to handle. Hydrogenation-distillation process comprises feeding streams forming gasoline pool containing benzene and hydrogen to a distillation column reactor loaded with a hydrogenation catalyst. The reactor is operated at moderate pressure and high temperature (US Patent No 5856602). The operational cost of this process is also high due to the use of catalyst. Besides it suffers from the drawbacks associated with hydrogen. Alkylation of benzene in streams forming gasoline pool followed by isomensation with zeolite catalyst is also employed to reduce benzene content in gasoline (US Patent Nos 854731 and 5811623). Besides being a multistep process it requires continuous regenerator of catalyst to make the process efficient. This makes the process expensive and requires special requirements of operation and automation. Extractive distillation of benzene from streams forming gasoline pool containing benzene with n-formylmorpholine is also used to reduce benzene content of gasoline (Hydroc. Proc. 52, 4, 139, April 1973). This process is very expensive as it requires high energy input and costly organic solvent, namely n-formylmorpholine. OBJECTS OF INVENTION An object of the invention is to provide a single step method of reducing toxic benzene content of gasoline below 1% by weight for use in automobiles, which eliminates use of catalyst and hazardous hydrogen and organic solvent and is simple, safe and easy to carry out. Another object of the invention is to provide a single step method of reducing toxic benzene content of gasoline below 1% by weight for use in automobiles, which is economical. DETAILED DESCRIPTION OF INVENTION According to the invention there is provided a single step method for reducing benzene content of gasoline below 1% by weight for particular use in automobiles, comprising the step of treating benzene contaminated gasoline with water in the weight ratio 1:1 to 3:1 at 25 -60kg/cm pressure and 150 to 260°C and recovering the gasoline from the reaction stream in a known manner. Preferably, the gasoline is treated with water in the weight ratio 1 : 1 at 50-53kg/cm2 pressure and 250°C. The method of the invention eliminates hazardous hydrogen and expensive organic solvent and catalysts and is carried out with water which is easily available in plenty and is inexpensive. It is, therefore, simple, safe and easy to carryout and is also economical. The following experimental examples are illustrative of the invention but not limitative of the scope thereof. Example 1 Gasoline (150 ml) containing 2.64% by weight benzene and water (150 ml) were charged into a 500 ml capacity high pressure reactor made of stainless steel and fitted with electric heaters and accessories such as temperature controllers, pressure safety devices, pressure and temperature indicators, gas charging ports, non-return valves, sampling ports and condensers. The reactor was closed and purged with nitrogen for 30 minutes following which nitrogen pressure was allowed to build up upto 53 kg/cm2 under heating upto 250°C. The pressure and temperature conditions were maintained for 2 hours. The treated gasoline was sampled through condenser maintained at -5°C with chilled water. Benzene content in the sampled gasoline was 0.7031% by weight. Example 2 The procedure of Example 1 was followed with gasoline (150 ml) containing 2.64% by weight benzene and water (150 ml). The reactor was maintained at 250°C and 50 Kg/cm11 pressure for 30 minutes. Benzene content in the sampled gasoline was 0.7683% by weight. Example 3 The procedure of Example 1 was followed with gasoline (200 ml) containing 2.64% by weight benzene and water (100 ml). The reactor was maintained at 250°C and 52 kg/cm2 pressure for 30 minutes. Benzene content in the sampled gasoline was 1.4295% by weight. Example 4 The procedure of Example 1 was followed with gasoline (225 ml) containing 2.64% by weight benzene and water (75 ml). The reactor was maintained at 250°C and 53 kg/cm2 pressure for 30 minutes. Benzene content in the sampled gasoline was 1.6746% by weight. Examples 3 and 4 clearly establish that when the gasoline to water ratio is less than that of the invention the reduction of benzene content in the gasoline is not below 1% by weight. We Claim: 1) A single step method for reducing benzene content of gasoline below 1% by weight for particular use in automobiles, comprising the step of treating benzene contaiminated gasoline with water in the weight ratio 1:1 to 3:1 at 25 - 60kg/cm2 pressure and 150 to 260°C and recovering the gasoline from the reaction stream in a known manner. 2) A single step method as claimed in claim 1, wherein the gasoline is treated with water in the weight ratio 1 : 1 at 50-53 kg/cm pressure and 250°C. 3) A single step method for reducing toxic benzene content of gasoline below 1% by weight for use in automobiles substantially as herein described particularly with reference to anyone of Examples 1 and 2. Dated this 22nd day of September 2000. (Arindam Paul) of DePENNING & DePENNING Agent for the Applicants

Full Text

FORM 2
THE PATENTS ACT 1970
(39 of 1970)
COMPLETE SPECIFICATION
(SEE SECTION 10, Rule 13)
TITLE
A single step method for reducing benzene content of gasoline below 1% by weight for particular use in automobiles
APPLICANTS
Larsen & Toubro Limited, L & T House, Ballard Estate, Mumbai - 400001, Maharashtra, India, an Indian company
INVENTORS
Under Section 28(2)
Chittoor Venkatesh Manian, Sanjiv Vasant Save,
Dananaickenkottai Venkataramanan Srinivasan and
Harshal Balawant Kulkarni, all of Larsen and Toubro
Limited, Powai Works, Saki Vihar Road, Mumbai 400072,
Maharashtra, India, all Indian nationals
The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed :

FIELD OF INVENTION
This invention relates to a single step method for reducing benzene content of gasoline. Benzene content may be reduced to below 1% by weight for particular use in automobiles.
PRIOR ART
Carbon monoxide, unburned hydrocarbon, oxides of nitrogen, sulphur dioxide, particulates containing sulfates, benzene or polynuclear aromatics are major pollutants from automobiles. Benzene causes leukemia and could also result in aplstic anemia and immuno and neuro toxicity. Considering the toxicity and carcinogenicity of benzene, emission norms of automobiles run on gasoline (petrol) require that benzene must be converted into benign components and benzene content in the gasoline should be below 1% by weight. Refineries making petrol for automobiles are thus required to ensure benzene content in the petrol below 1% by weight. Several processes for reducing benzene content of gasoline below 1% by weight are reported.

Benzene saturation process comprises preheating streams fonning gasoline pool containing benzene with steam followed by mixing with hydrogen and passing the mixture over a bed of noble metal catalyst at elevated temperatures and pressures (US Patent No 5663466A). This process involves multiple steps and uses catalyst which is a consumable item rendering its operating cost high. Preheating by steam requires additional thermal energy. Hydrogen is highly explosive and hazardous and very difficult to handle.
Hydrogenation-distillation process comprises feeding streams forming gasoline pool containing benzene and hydrogen to a distillation column reactor loaded with a hydrogenation catalyst. The reactor is operated at moderate pressure and high temperature (US Patent No 5856602). The operational cost of this process is also high due to the use of catalyst. Besides it suffers from the drawbacks associated with hydrogen.
Alkylation of benzene in streams forming gasoline pool followed by isomensation with zeolite catalyst is also

employed to reduce benzene content in gasoline (US Patent Nos 854731 and 5811623). Besides being a multistep process it requires continuous regenerator of catalyst to make the process efficient. This makes the process expensive and requires special requirements of operation and automation.
Extractive distillation of benzene from streams forming gasoline pool containing benzene with n-formylmorpholine is also used to reduce benzene content of gasoline (Hydroc. Proc. 52, 4, 139, April 1973). This process is very expensive as it requires high energy input and costly organic solvent, namely n-formylmorpholine.
OBJECTS OF INVENTION
An object of the invention is to provide a single step method of reducing toxic benzene content of gasoline below 1% by weight for use in automobiles, which eliminates use of catalyst and hazardous hydrogen and organic solvent and is simple, safe and easy to carry out.

Another object of the invention is to provide a single step method of reducing toxic benzene content of gasoline below 1% by weight for use in automobiles, which is economical.
DETAILED DESCRIPTION OF INVENTION
According to the invention there is provided a single step method for reducing benzene content of gasoline below 1% by weight for particular use in automobiles, comprising the step of treating benzene contaminated gasoline with water in the weight ratio 1:1 to 3:1 at 25 -60kg/cm pressure and 150 to 260°C and recovering the gasoline from the reaction stream in a known manner.
Preferably, the gasoline is treated with water in the weight ratio 1 : 1 at 50-53kg/cm2 pressure and 250°C.
The method of the invention eliminates hazardous hydrogen and expensive organic solvent and catalysts and is carried out with water which is easily available in plenty and is inexpensive. It is, therefore, simple, safe and easy to carryout and is also economical.

The following experimental examples are illustrative of the invention but not limitative of the scope thereof.
Example 1
Gasoline (150 ml) containing 2.64% by weight benzene and water (150 ml) were charged into a 500 ml capacity high pressure reactor made of stainless steel and fitted with electric heaters and accessories such as temperature controllers, pressure safety devices, pressure and temperature indicators, gas charging ports, non-return valves, sampling ports and condensers. The reactor was closed and purged with nitrogen for 30 minutes following which nitrogen pressure was allowed to build up upto 53 kg/cm2 under heating upto 250°C. The pressure and temperature conditions were maintained for 2 hours. The treated gasoline was sampled through condenser maintained at -5°C with chilled water. Benzene content in the sampled gasoline was 0.7031% by weight.

Example 2
The procedure of Example 1 was followed with gasoline (150 ml) containing 2.64% by weight benzene and water (150 ml). The reactor was maintained at 250°C and 50 Kg/cm11 pressure for 30 minutes. Benzene content in the sampled gasoline was 0.7683% by weight.
Example 3
The procedure of Example 1 was followed with gasoline (200 ml) containing 2.64% by weight benzene and water (100 ml). The reactor was maintained at 250°C and 52 kg/cm2 pressure for 30 minutes. Benzene content in the sampled gasoline was 1.4295% by weight.
Example 4
The procedure of Example 1 was followed with gasoline (225 ml) containing 2.64% by weight benzene and water (75 ml). The reactor was

maintained at 250°C and 53 kg/cm2 pressure for 30 minutes. Benzene content in the sampled gasoline was 1.6746% by weight.
Examples 3 and 4 clearly establish that when the gasoline to water ratio is less than that of the invention the reduction of benzene content in the gasoline is not below 1% by weight.

We Claim:
1) A single step method for reducing benzene content of gasoline below 1% by weight for particular use in automobiles, comprising the step of treating benzene contaiminated gasoline with water in the weight ratio 1:1 to 3:1 at 25 - 60kg/cm2 pressure and 150 to 260°C and recovering the gasoline from the reaction stream in a known manner.
2) A single step method as claimed in claim 1, wherein the gasoline is treated with water in the weight ratio 1 : 1 at 50-53 kg/cm pressure and 250°C.
3) A single step method for reducing toxic benzene content of gasoline below 1% by weight for use in automobiles substantially as herein described particularly with reference to anyone of Examples 1 and 2.
Dated this 22nd day of September 2000.
(Arindam Paul) of DePENNING & DePENNING Agent for the Applicants

Documents:

877-mum-2000-cancelled pages(10-03-2004).pdf

877-mum-2000-claims(granted)-(10-03-2004).pdf

877-mum-2000-claims(granted)-(25-09-2000).doc

877-mum-2000-correspondence(12-08-2004).pdf

877-mum-2000-correspondence(ipo)-(12-12-2005).pdf

877-mum-2000-form 1(25-09-2000).pdf

877-mum-2000-form 19(19-08-2003).pdf

877-mum-2000-form 2(granted)-(10-03-2004).pdf

877-mum-2000-form 2(granted)-(25-09-2000).doc

877-mum-2000-form 26(25-09-2000).pdf

877-mum-2000-form 3(25-09-2000).pdf

877-mum-2000-form 8(19-02-2001).pdf

877-mum-2000-power of attorney(14-11-2003).pdf

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Patent Number

197730

Indian Patent Application Number

877/MUM/2000

PG Journal Number

41/2007

Publication Date

12-Oct-2007

Grant Date

12-Dec-2005

Date of Filing

25-Sep-2000

Name of Patentee

LARSEN & TOUBRO LIMITED

Applicant Address

L & T HOUSE, BALLARD ESTATE, MUMBAI 400001, MAHARASHTRA, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	CHITTOOR VENKATESH MANIAN	LARSEN & TOUBRO LIMITED, POWAI WORKS, SAKI VIHAR ROAD, MUMBAI 400 072, MAHARASHTRA, INDIA.
2	SANJIV VASANT SAVE	LARSEN & TOUBRO LIMITED, POWAI WORKS, SAKI VIHAR ROAD, MUMBAI 400 072, MAHARASHTRA, INDIA.
3	DANANAICKENKOTTAI VENKATARAMANAN SRINIVASAN	LARSEN & TOUBRO LIMITED, POWAI WORKS, SAKI VIHAR ROAD, MUMBAI 400 072, MAHARASHTRA, INDIA.
4	HARSHAL BALAWANT KULKARNI	LARSEN & TOUBRO LIMITED, POWAI WORKS, SAKI VIHAR ROAD, MUMBAI 400 072, MAHARASHTRA, INDIA.

PCT International Classification Number

N/A

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA