Title of Invention	"RECUPERATIVE LIQUEFIED PETROLEUM GAS (LPG) VORTEX BURNER SYSTEM"
Abstract	A recuperative liquefied petroleum gas vortex burner system having double layered cylindrical enclosure for air and asymmetric fuel injection is designed and developed. The air, which enters the burner system, goes downward and enters the combustion chamber through the two tangential ports at the bottom, this ensures that the air flows through the burner wall and get preheated before entering the combustion zone. The LPG fuel fed from the port located at the circumference close to the tangential entry of the air on the bottom side of the burner. This burner system has the capability to stabilize the flame with ultra lean mixture of extremely low overall equivalence ratio, which is further from the flammability limit of the LPG-air mixture and also ensures higher combustion efficiency.

Title of Invention

"RECUPERATIVE LIQUEFIED PETROLEUM GAS (LPG) VORTEX BURNER SYSTEM"

Abstract

A recuperative liquefied petroleum gas vortex burner system having double layered cylindrical enclosure for air and asymmetric fuel injection is designed and developed. The air, which enters the burner system, goes downward and enters the combustion chamber through the two tangential ports at the bottom, this ensures that the air flows through the burner wall and get preheated before entering the combustion zone. The LPG fuel fed from the port located at the circumference close to the tangential entry of the air on the bottom side of the burner. This burner system has the capability to stabilize the flame with ultra lean mixture of extremely low overall equivalence ratio, which is further from the flammability limit of the LPG-air mixture and also ensures higher combustion efficiency.

Full Text	Recuperative Liquefied Petroleum Gas (LPG) Vortex Burner System Field of Invention The instant invention relates to a LPG burner system and more specifically recuperative LPG Vortex Burner System. Background of the Invention The present invention is related to gas burner system, and in particular to recuperative LPG vortex burner system, which provides highly efficient combustion capacity with lowest carbon monoxide emission level along with lowest nitrous oxide emissions for burner systems. Currently various combustion applications like gas turbines in power systems employ lean premixed combustors as it is capable of attaining very low emissions and efficient fuel utilization. Many of these lean premixed burners rely on the attainment of near-perfect homogenous mixture before combustion to achieve low emission, as NOX formation is a function of flame temperature and various degrees of mixing air and fuel gases. However, these lean premixed burners are often associated with the problem of flash back and low combustion efficiency and also exhibit combustion instability. In the era of increasingly stringent environment regulations for emissions, lean premixed combustion systems have played a major role in curbing NOX emissions. However, lean premixed combustion systems are associated with certain drawbacks. Particularly stability and efficiency are the two major parameters, which are always assessed for any good combustion system. The emissions of other pollutants such as carbon monoxide are also substantially high. European Patent EP1486728 titled "Recuperative burner and recuperator" discusses a ceramic recuperator for recuperative burner. The burner has folds extending in spiral fashion in relation to longitudinal axis of recuperator, and pipe section has outer and inner pipes forming outer and inner chambers for passage of fluid. In this invention they claim about achieving a good heat exchange between the flue gases and the combustion air. Another European Patent application EP1167879A1 titled "Recuperative burner with gas distribution unit" proposed a gas burner with counter flow heat exchanger for exhaust heat recovery. The burner has parallel channels linking burner body with combustion chamber, and gas guide system to direct feed and exhaust flows, European Patent EP1016827B1 titled "Integrated recuperative burner" reveals recuperative burner used as a radiant burner or in a thermo photovoltaic generator. This burner has a burner body containing channels for gas supply to and waste gas withdrawal from a combustion chamber. Operation of this burner is based on counter current heat exchanger. The present invention proposes to over comes above-mentioned drawbacks and also provide high combustion efficiency, to this effect an attempt has been made to design and develop a novel recuperative vortex LPG burner based on asymmetric fuel injection to the vortex air. Object and Summary of the Invention To obviate the aforesaid drawbacks the object of the instant invention is to provide a novel recuperative vortex burner system for higher combustion efficiency. Another object of the invention is to extract the heat from the flue gases to preheat the incoming air. Yet another object of the invention is to provide fuel saving as heat loss is compensated in comparison to the conventional burners fuel consumption. Yet another object of the invention is to provide reduction in the emission. Yet another object of the proposed invention is the use of asymmetric fuel injection into vortex air. A Recuperative Vortex Burner System comprising: a first co-centric cylinder for storing and injecting air; a second co-centric cylinder encapsulated in said first co-centric cylinder for burning the mixture of fuel gases and air received from said first co- centric cylinder; and a layer of insulation at outer layer of said first co-centric cylinder for insulating from outside environment; wherein: said first co-centric cylinder has an air entry port for receiving air at the top of the first co-centric cylinder; said second co-centric cylinder has at least one tangential air injecting port at the bottom of said second co-centric cylinder for injecting air from said first co-centric cylinder; and at least one fuel injecting port at the periphery of said second co-centric cylinder close to the tangential air injecting port. The solution provided by the proposed vortex burner system may find applications in gas turbines, furnaces, and other combustion systems as it provides high flame stability and maintaining high turn down ratio while keeping low emission level. All these can be achieved due to the use of asymmetric fuel injection into the vortex air and location of fuel injection ports Brief Descriptions of the Drawings The present invention is described with the help of accompanying drawings: Figure 1 shows the proposed recuperative vortex burner. Figure 2 shows the vertical cross section of the burner showing fuel and air injection port. Figure 3 illustrates the flame structure of the recuperative vortex burner at very low overall equivalence ratio. Detail Description of the Invention Present invention deals with the recuperative LPG vortex burner system. In this burner arrangement, fuel and air are introduced separately creating a partially premixed vortex flame. Though the flue gases do not come in contact directly with incoming air, they harness heat from the exhaust gas to preheat the incoming air. Most importantly, the flame could be stabilized in this burner with ultra lean mixture with an overall equivalence ratio of around 0.18, which is beyond the flammability limit of LPG-air mixture. The combustion zone is operated at equivalence ratio very close to the blowout limit. It is well established that the smaller the margin between stable combustion and flame blowout, the lower will be the output of NOX. Higher efficiency can be achieved even with an ultra lean mixture, along with NOX emission level even upto as low as 4 ppm (parts per million). The proposed vortex burner system is a double-layered stainless steel burner having tangential air entry as shown in Figure-1. Figure-2 illustrates a vertical cross section of the proposed burner is drawn. The figures show multi layered burner system, in which first layer is to protect the burner system from the outside environment. An air-storing chamber exists within the first layer, which stores the incoming air from the top (1) of the burner system. Third layer is combustion chamber (5), at the bottom of the air-storing chamber there are tangential air entry ports (2, 3) which injects air into the combustion chamber (5). While air travels through top to bottom of air storing chamber it collects the heat from the outer portion of the combustion chamber (5) to get the air preheated before entering the combustion zone. Asymmetric fuel injection port (4) is made at the bottom of the burner system. In asymmetric fuel injection process the fuel is injected away from the center of the burner as shown in Figure-2, which is nearby the tangential air entry ports (2, 3). This configuration helps in better mixing of fuel and air before actual combustion takes place and this method results in substantial improvement of flame stability. By doing this a strong swirl will be generated inside the burner which enables to achiever high turn down ratio (ratio of maximum to minimum power) and higher combustion efficiency with lower emission level. The combustion gases do not come in contact directly with incoming air. However, the heat from the exhaust gas is transferred to preheat the incoming air. The fuel is injected asymmetrically into the vortex air. The LPG fuel is fed from the fuel injection port (4) located at the circumference close to the tangential air entry ports (2, 3) as shown in Figure-2.Then combustion occurs in the combustion chamber (5) in a ring shape as shown in Figure-3. Most importantly, the flame can be stabilized in this burner system with ultra lean mixture having equivalence ratio of 0.18, which is beyond the flammability limit of LPG-air mixture. Higher combustion efficiency can be achieved as compared to lean premixed flame burner even at ultra lean mixture. The emission levels of various gases like NOX, CO and CO2 was found to be very low for this burner. The NOx emission level of 4 ppm is achieved with a moderate concentration of CO. The present invention has several advantages over existing burner systems. Present burner can achiever a turn down ratio of around 8, whereas prior inventions could only achieve up to only 5. As the present system offers higher fuel efficiency, less number of burners is required in comparison to the traditional burners for the same job. Heat transfer from the exhaust gases to the combustion air helps in reducing the temperature of the flue gas escaping to the atmosphere. All documents cited in the description are incorporated herein by reference The present invention is not to be limited in scope by the specific embodiments and examples which are intended as illustrations of a number of aspects of the invention and any embodiments which are functionally equivalent are within the scope of this invention. Those skilled in the art will know, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. These and all other equivalents are intended to be encompassed by the following claims. We claim: 1. A Recuperative Vortex Burner System comprising: a first co-centric cylinder for storing and injecting air; a second co-centric cylinder encapsulated in said first co-centric cylinder for burning the mixture of fuel gases and air received from said first co-centric cylinder; and a layer of insulation at outer layer of said first co-centric cylinder for insulating from outside environment; wherein: said first co-centric cylinder has an air entry port for receiving air at the top of the first co-centric cylinder; said second co-centric cylinder has at least one tangential air injecting port to form vortex air flow at the bottom of said second co-centric cylinder for injecting said vortex air flow from said first co-centric cylinder to the combustion chamber; and at least one fuel injecting port at the periphery of said second co-centric cylinder close to the tangential air injecting port for injecting asymmetric fuel into the vortex air flow to maintain high combustion efficiency. A Recuperative Vortex Burner System as claimed in claim 1, wherein a heat- conducting wall is provided for said second co-centric cylinder for preheating the air before combustion. A Recuperative Vortex Burner System as claimed in claim 1, wherein said second co-centric cylinder is capable of accepting ultra lean mixture of air and fuel gases. A Recuperative Vortex Burner System as claimed in claim 1, wherein said second co-centric cylinder is capable of achieving lower emissions of NOX, CO and CO2. A Recuperative Vortex Burner System substantially as herein described with reference to and as illustrated in the accompanying drawings.

Full Text

Recuperative Liquefied Petroleum Gas (LPG) Vortex Burner System
Field of Invention
The instant invention relates to a LPG burner system and more specifically recuperative LPG Vortex Burner System.
Background of the Invention
The present invention is related to gas burner system, and in particular to recuperative LPG vortex burner system, which provides highly efficient combustion capacity with lowest carbon monoxide emission level along with lowest nitrous oxide emissions for burner systems.
Currently various combustion applications like gas turbines in power systems employ lean premixed combustors as it is capable of attaining very low emissions and efficient fuel utilization. Many of these lean premixed burners rely on the attainment of near-perfect homogenous mixture before combustion to achieve low emission, as NOX formation is a function of flame temperature and various degrees of mixing air and fuel gases. However, these lean premixed burners are often associated with the problem of flash back and low combustion efficiency and also exhibit combustion instability.
In the era of increasingly stringent environment regulations for emissions, lean premixed combustion systems have played a major role in curbing NOX emissions. However, lean premixed combustion systems are associated with certain drawbacks. Particularly stability and efficiency are the two major parameters, which are always assessed for any good combustion system. The emissions of other pollutants such as carbon monoxide are also substantially high.
European Patent EP1486728 titled "Recuperative burner and recuperator" discusses a ceramic recuperator for recuperative burner. The burner has folds extending in spiral fashion in relation to longitudinal axis of recuperator, and pipe section has outer and inner pipes forming outer and inner chambers for passage of fluid. In this invention they
claim about achieving a good heat exchange between the flue gases and the combustion air.
Another European Patent application EP1167879A1 titled "Recuperative burner with gas distribution unit" proposed a gas burner with counter flow heat exchanger for exhaust heat recovery. The burner has parallel channels linking burner body with combustion chamber, and gas guide system to direct feed and exhaust flows,
European Patent EP1016827B1 titled "Integrated recuperative burner" reveals recuperative burner used as a radiant burner or in a thermo photovoltaic generator. This burner has a burner body containing channels for gas supply to and waste gas withdrawal from a combustion chamber. Operation of this burner is based on counter current heat exchanger.
The present invention proposes to over comes above-mentioned drawbacks and also provide high combustion efficiency, to this effect an attempt has been made to design and develop a novel recuperative vortex LPG burner based on asymmetric fuel injection to the vortex air.
Object and Summary of the Invention
To obviate the aforesaid drawbacks the object of the instant invention is to provide a novel recuperative vortex burner system for higher combustion efficiency.
Another object of the invention is to extract the heat from the flue gases to preheat the incoming air.
Yet another object of the invention is to provide fuel saving as heat loss is compensated in comparison to the conventional burners fuel consumption.
Yet another object of the invention is to provide reduction in the emission.
Yet another object of the proposed invention is the use of asymmetric fuel injection into vortex air.
A Recuperative Vortex Burner System comprising:
a first co-centric cylinder for storing and injecting air;
a second co-centric cylinder encapsulated in said first co-centric cylinder
for burning the mixture of fuel gases and air received from said first co-
centric cylinder; and
a layer of insulation at outer layer of said first co-centric cylinder for
insulating from outside environment;
wherein:
said first co-centric cylinder has an air entry port for receiving air at the
top of the first co-centric cylinder;
said second co-centric cylinder has at least one tangential air injecting port
at the bottom of said second co-centric cylinder for injecting air from said
first co-centric cylinder; and
at least one fuel injecting port at the periphery of said second co-centric
cylinder close to the tangential air injecting port.
The solution provided by the proposed vortex burner system may find applications in gas turbines, furnaces, and other combustion systems as it provides high flame stability and maintaining high turn down ratio while keeping low emission level. All these can be achieved due to the use of asymmetric fuel injection into the vortex air and location of fuel injection ports
Brief Descriptions of the Drawings
The present invention is described with the help of accompanying drawings:
Figure 1 shows the proposed recuperative vortex burner.
Figure 2 shows the vertical cross section of the burner showing fuel and air injection port.
Figure 3 illustrates the flame structure of the recuperative vortex burner at very low overall equivalence ratio.
Detail Description of the Invention
Present invention deals with the recuperative LPG vortex burner system. In this burner arrangement, fuel and air are introduced separately creating a partially premixed vortex flame. Though the flue gases do not come in contact directly with incoming air, they harness heat from the exhaust gas to preheat the incoming air. Most importantly, the flame could be stabilized in this burner with ultra lean mixture with an overall equivalence ratio of around 0.18, which is beyond the flammability limit of LPG-air mixture. The combustion zone is operated at equivalence ratio very close to the blowout limit. It is well established that the smaller the margin between stable combustion and flame blowout, the lower will be the output of NOX. Higher efficiency can be achieved even with an ultra lean mixture, along with NOX emission level even upto as low as 4 ppm (parts per million).
The proposed vortex burner system is a double-layered stainless steel burner having tangential air entry as shown in Figure-1. Figure-2 illustrates a vertical cross section of the proposed burner is drawn. The figures show multi layered burner system, in which first layer is to protect the burner system from the outside environment. An air-storing chamber exists within the first layer, which stores the incoming air from the top (1) of the burner system. Third layer is combustion chamber (5), at the bottom of the air-storing chamber there are tangential air entry ports (2, 3) which injects air into the combustion chamber (5). While air travels through top to bottom of air storing chamber it collects the heat from the outer portion of the combustion chamber (5) to get the air preheated before entering the combustion zone. Asymmetric fuel injection port (4) is made at the bottom of the burner system. In asymmetric fuel injection process the fuel is injected away from the center of the burner as shown in Figure-2, which is nearby the tangential air entry ports (2, 3). This configuration helps in better mixing of fuel and air before actual combustion takes place and this method results in substantial improvement of flame stability. By doing this a strong swirl will be generated inside the burner which enables to achiever high turn down
ratio (ratio of maximum to minimum power) and higher combustion efficiency with lower emission level.
The combustion gases do not come in contact directly with incoming air. However, the heat from the exhaust gas is transferred to preheat the incoming air. The fuel is injected asymmetrically into the vortex air. The LPG fuel is fed from the fuel injection port (4) located at the circumference close to the tangential air entry ports (2, 3) as shown in Figure-2.Then combustion occurs in the combustion chamber (5) in a ring shape as shown in Figure-3. Most importantly, the flame can be stabilized in this burner system with ultra lean mixture having equivalence ratio of 0.18, which is beyond the flammability limit of LPG-air mixture. Higher combustion efficiency can be achieved as compared to lean premixed flame burner even at ultra lean mixture.
The emission levels of various gases like NOX, CO and CO2 was found to be very low for this burner. The NOx emission level of 4 ppm is achieved with a moderate concentration of CO. The present invention has several advantages over existing burner systems. Present burner can achiever a turn down ratio of around 8, whereas prior inventions could only achieve up to only 5. As the present system offers higher fuel efficiency, less number of burners is required in comparison to the traditional burners for the same job. Heat transfer from the exhaust gases to the combustion air helps in reducing the temperature of the flue gas escaping to the atmosphere.
All documents cited in the description are incorporated herein by reference The present invention is not to be limited in scope by the specific embodiments and examples which are intended as illustrations of a number of aspects of the invention and any embodiments which are functionally equivalent are within the scope of this invention. Those skilled in the art will know, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. These and all other equivalents are intended to be encompassed by the following claims.

We claim:
1. A Recuperative Vortex Burner System comprising:
a first co-centric cylinder for storing and injecting air;
a second co-centric cylinder encapsulated in said first co-centric cylinder for burning the mixture of fuel gases and air received from said first co-centric cylinder; and
a layer of insulation at outer layer of said first co-centric cylinder for insulating from outside environment; wherein:
said first co-centric cylinder has an air entry port for receiving air at the top of
the first co-centric cylinder;
said second co-centric cylinder has at least one tangential air injecting port to
form vortex air flow at the bottom of said second co-centric cylinder for
injecting said vortex air flow from said first co-centric cylinder to the
combustion chamber; and
at least one fuel injecting port at the periphery of said second co-centric
cylinder close to the tangential air injecting port for injecting asymmetric fuel
into the vortex air flow to maintain high combustion efficiency.
A Recuperative Vortex Burner System as claimed in claim 1, wherein a heat-
conducting wall is provided for said second co-centric cylinder for preheating the
air before combustion.
A Recuperative Vortex Burner System as claimed in claim 1, wherein said second
co-centric cylinder is capable of accepting ultra lean mixture of air and fuel gases.
A Recuperative Vortex Burner System as claimed in claim 1, wherein said second
co-centric cylinder is capable of achieving lower emissions of NOX, CO and CO2.
A Recuperative Vortex Burner System substantially as herein described with reference to and as illustrated in the accompanying drawings.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=suWUn2RAjpulpIw5tXvKEQ==&loc=+mN2fYxnTC4l0fUd8W4CAA==

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Patent Number

269392

Indian Patent Application Number

3197/DEL/2005

PG Journal Number

44/2015

Publication Date

30-Oct-2015

Grant Date

19-Oct-2015

Date of Filing

29-Nov-2005

Name of Patentee

INDIAN INSTITUTE OF TECHNOLOGY

Applicant Address

KANPUR-208016, UTTAR PRADESH, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	DR. D.P. MISHRA	INDIAN NATIONAL OF INDIAN INSTITUTE OF TECHNOLOGY, KANPUR, DEPARTMENT OF AEROSPACE ENGINEERING, KANPUR-208016, UTTAR PRADESH, INDIA.
2	S.C. NAYAK	INDIAN NATIONAL OF INDIAN INSTITUTE OF TECHNOLOGY, KANPUR, DEPARTMENT OF AEROSPACE ENGINEERING, KANPUR-208016, UTTAR PRADESH, INDIA.

PCT International Classification Number

B23K 10/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA