Description:‘AN IMPROVED LOW NOX OIL AND GAS FIRED BURNER’

FIELD OF THE INVENTION:
[001] The invention is related to a fuel oil and gas system in thermal power plant engineering and more particularly to the operation of Burners and in general to the firing system. Current invention is to improve the functioning of the burner with respect to damper movement especially during hot condition.
[002] The subject invention is related to improvements in oil and gas fired Low NOx Burner. The invention is particularly directed to an improved Low Nox oil and gas fired Burner.

BACKGROUND / PRIOR ART OF THE INVENTION:
[003] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[004] Due to enhanced fossil fuel consumption and limited reserves of oil and gas reserves, attention is focused on improving their combustion efficiency through improved design of Burner. Apart from above, stringent environmental norms for industrial gaseous pollutant emissions are also forcing industrialist to upgrade their existing Burners to reduce gaseous pollutants and improve operations. In this regard, a special attention is focused on power, refinery and industrial sectors to develop high efficient low pollutant emission burners. In recent years many novel burner designs have been evolved for steam generation. Since, burner is an important element in firing the fuels under controlled conditions, design of burner plays a crucial role in deciding the flue gas composition, amount of unburnt carbon, flame stability, flame impingement and net efficiency of the plant. Therefore, continuous efforts are made in developing improved burner to meet these criteria.

[005] Also, in the context of growing concern for the burner operation and incidents of the recent past, there is a need and dire requirement of introducing the features and sub systems in the burner, not only to boost the confidence of users but also to have the much desired improved burner operation.

PRIOR ART:
[006] Indian Patent Application No. IN1070KOL2012A depicts a dual gaseous fuel burner for higher and lower calorific value with individual air supply for each of the fuel. However, the liquid fuel injection is missing in this design.

[007] Indian Patent Application No. IN963KOL2013A discloses a dual gaseous fuel burner for firing high calorific value fuel and low calorific value fuel with single air supply. The air supply was provided through a common pipe for both fuels, hence the design is compact. However, the liquid fuel injection is not part of this design.

[008] Indian Patent Application No. IN583KOL2014A describes a gas-liquid dual fuel burner system for liquid fuels and low calorific value fuel gases. Swirl block was provided for both air and gaseous fuel supply for better flame stability. However, it was specially designed for low calorific value gaseous fuels only and not for high calorific value fuels such as natural gas.

[009] Indian patent application No IN594KOL2015A, describes a low NOx emitting solid fuel fired wall burner apparatus for boilers in thermal power plants. This design was useful for firing pulverized solid fuels and liquid fuel firing during start-up of the boiler. However, in this design provision for gaseous fuel firing is missing.

[0010] Indian Patent Application No 201631032232 describes a multifuel wall burner to fire two gaseous fuels, liquid fuel and a solid fuel for industrial applications. In which air flow and gaseous fuel flow injection is very different from the burner.

[0011] Although many novel burner concepts were published, describing about dual fuel burner with gas-liquid for different industries but the present proposed design significantly deviates from others. The present innovation is described for efficient fuel firing and producing minimal pollutant emission in the steam generation applications with improved design specially with respect to primary and secondary damper movement, which is a great concern in almost all the above described burners. The burner of proposed application is having improved flexibility, is user friendly in operation and easy to maintain in the boiler during its service.

OBJECTS OF THE INVENTION:
[0012] Primary object of the invention is to propose an improved Low Nox oil and gas fired Burner, which obviates shortcomings of the prior art(s).

[0013] An object of the invention is to propose an improved Low Nox oil and gas fired Burner which provides a reliable means thereby the burner operates smoothly and enables proper combustion of fuel.

[0014] Another object of the invention is to propose an improved Low Nox oil and gas fired Burner which incorporates a vital primary and secondary air roller assemblies for the effective movement of dampers.

[0015] Still another object of the invention is to propose an improved Low Nox oil and gas fired Burner which provides improved flame length thereby reducing flame impingement issues.

[0016] Yet another object of the invention is to propose an improved Low Nox oil and gas fired Burner Which provides incorporation of improved version of gas spud for designed velocity and temperature profiles.

[0017] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY OF THE INVENTION:
[0018] One or more drawbacks of conventional systems and process are overcome, and additional advantages are provided through the apparatus/composition and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.

[0019] The objective of the present invention is accomplished by introducing much needed roller assemblies with innovative design for both primary and secondary air sleeves / shields. The overheating issues of stabilizer plate in many of the recent burners is resolved by suitably redesigning the stabilizer plate [11].

[0020] Incorporation of improved gas spuds or gas nozzles results in better flame profile with optimized flame velocities and temperature profiles.

[0021] According to this invention, there is provided an improved Low Nox oil and gas fired Burner comprises of Gas chamber [1], Primary air drum assembly [2], secondary air drum assembly [6], oil gun assembly, Gas pipe igniter assembly [12] and burner throat, wherein air from wind box enters the burner, is composed of said secondary air drum [6] with a secondary air swirler [3] and said primary air drum [2] with a primary air swirler [9]; wherein
the Gas chamber [1] is connected to multitude of gas lances [5], in which the gas lances [5] are connected to gas spud/nozzle;
said primary air drum [2] is connected to front portion of burner, in which primary shield assembly [4] covers said primary air drum [2] and primary shield assembly [4] moves on said primary air drum [2] forward/backward;
said secondary air drum [6] is connected to front portion of burner, in which secondary air shield assembly [8] covers said secondary air drum [6] and the secondary air shield assembly [8] moves on said secondary air drum [6] forward/backward.

[0022] All the above new features made this burner innovative and unique.

[0023] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

[0024] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.

[0025] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:

[0026] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:

Figure 1 shows: Sectional side view of improved Low Nox oil and gas fired Burner according to the present invention;
Figure 2 shows: Secondary Air Shield with roller assembly of the invention;
Figure 3 shows: Primary air sleeve or shield with roller assembly of the invention;
Figure 4 shows: Primary air drum with guide assembly of the invention;
Figure 5 shows: Secondary air drum with guide assembly of the invention;
Figure 6 shows: Stabilizer plate design of the invention;
Figure 7 shows: Gas spud design of the invention;
Figure 8 shows: Gas Lance orientation of the invention;
Figure 9 shows: Clearance between drum and air shield both for primary air and secondary air according to the invention.
Figure 10 shows: Connection of roller assemblies with air shield; A shows the typical roller assembly for secondary air shield and B is for primary air shield.
Figure 11 shows: Side roller assembly of outer air shield.
Figure 12 shows: Redesigned stabiliser plate.

[0027] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DEATIL DESCRIPTION OF THE PREFERRED EMBODIMENT OF INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:

[0028] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

[0029] The present invention makes a disclosure regarding a technology pertaining to an invention directed to an improved Low Nox oil and gas fired Burner.

[0030] The general construction of the Low NOX Burner is as shown in the Fig. 1. Essentially the burner comprises of Gas chamber [1], Primary air drum assembly [2], secondary air drum assembly [6], oil gun assembly, Gas pipe igniter assembly [12] and burner throat.

[0031] The air from the wind box enters the burner, is composed of a secondary air drum [6] with a secondary air swirler [3] and a primary air drum [2] with a primary air swirler [9].

[0032] The Gas chamber [1] is connected to gas lances [5]. The gas lances [5] is further connected to gas spud/nozzle [best seen in fig. 7]. Said primary air drum [2] is connected to front portion of burner. Primary shield assembly [4] covers said primary air drum [2]. Primary shield assembly [4] moves on said primary air drum [2] forward/backward. Said secondary air drum [6] is connected to front portion of burner. Secondary air shield assembly [8] covers said secondary air drum [6]. The secondary air shield assembly [8] moves on said secondary air drum [6] forward/backward.

[0033] The secondary swirler assembly [3] is connected to secondary air drum assembly [6] and primer swirler assembly [9] is connected to the primary air drum assembly [2]. The secondary swirler assembly [3] and primer swirler assembly [9] are provided in connection with stabilizer plate [11].

[0034] The above assembly is mounted on burner mounting flange [10].

[0035] The secondary air sleeves are operated from the burner front by means of two power cylinder. By operating the power cylinder, the air sleeve can be moved backward or forward, thereby changing the total amount of air admitted to the burner.
[0036] The purpose of secondary air sleeve is to open/close the air to the burners and around the periphery of each individual burner.

[0037] A portion of the air entering the register is admitted as primary air to the primary air drum. The purpose of the primary air is twofold: (1) To introduce air at the gun tip for initial combustion (2) To fill the vortex created by combustion in the secondary air zone, thus preventing the fire from drawing back into the burner nozzle, with resulting overheating and fouling.

[0038] A gas plenum chamber is constructed as a part of the front plate. This gas plenum ensures an even flow of gas to the multi lance gas burner arrangement. The gas lances are fitted with nozzles and are equispaced around swirler.

[0039] Gas lances [5] are provided for lighting off, warming up and for load carrying services.

[0040] After the burner is lit, the primary air sleeve should be opened gradually and adjusted, if necessary, to obtain a satisfactory flame.

[0041] Air sleeves or air dampers are primarily meant for the control of air to be admitted into furnace. Thus proper combustion depends on the operation of sleeves. Thus in the present invention, focus has been given to improve the operation of primary and secondary air sleeves /air shields /air dampers.

Roller Assembly arrangement in Burner: -
[0042] In a power plant burners get heated due to Radiation from Furnace. In addition to the above, burner parts are exposed to heat due to conduction, as parts of the burner are in contact to each other. The best way to reduce heating through conduction is to reduce the contact area. In the proposed design the contact area has been reduced in great extent by an innovative way and by adopting to single point contact between roller and guide shaft.

[0043] Apart from reducing heat transfer between the roller and guide shaft, single point Contact is able to achieve the following benefits:
a) Reduction in the friction between parts of burner considerably.
b) Roller arrangement of primary and secondary shield assemblies will have linear contact instead of surface contact which considerably smoothens the movement of roller over guide shaft for both primary and secondary assemblies (Refer Fig. No.10).

ROLLER ASSLY:
a) In a roller assembly, there are three rollers in a row with individual mounting plate to limit the effect of thermal expansion of the air shield. Also it allows the free expansion (Refer Fig. No 11).

REDESIGN OF STABILISER PLATE:
The salient features of redesigned stabiliser plate are as follows:
1. Having less area compared to prevailing design which is exposed to continuous heating.
2. Sufficient cuts and gaps are provided in the stabiliser plate so that it can take care of the thermal expansions and cooling provision (allows the air to pass through it) without getting distorted.
(Refer Fig. No 12)

ADVANTAGES/FEATURES OF THE INVENTION:
- The burner of invention is capable of operating smoothly with respect to primary and secondary air shield movement (Fig.2 and Fig 3) and prevents the jamming of shields/sleeves during the cold as well as hot condition and addresses the issue. The innovative roller assembly provided in the burner results in frictionless movement of primary and secondary air shield over the primary and secondary drums respectively (Fig.4 and Fig 5). Thus, it not only aides in better control of the air but also smoothens the operation or movement of sleeves or shields.
- The burner has improved design to take care the thermal expansion of the primary air drum and primary air shields as well as secondary air drum and secondary air shields. The material selection and appropriate clearances between assembly parts (Fig.9) are maintained to allow the expected thermal expansions. Thus, it limits the distortions resulting from restricted thermal expansions.
- The improved shield movements for both secondary air and primary sleeves (Fig 2 and Fig.3) results in less human power or force required for the respective sleeve/shield/damper movement.
- The stated burner has due protection for gas spuds or gas nozzles and is well protected by the suitable re-orientation of gas lances and gas spuds (Fig.8) from the accidental fall of oil on the gas spuds and further catching the fire and burning out.
- The burner has improved design, that ensures the safety of inside parts of burner from flame through effective and improved design of stabilizer plate (Fig. 6). Stabilizer plate is designed to suit better recirculation of air with less material thereby reducing the possibility for overheating. Thus, it results in extended life for stabilizer plate.
- The improved burner design and modified gas spuds (Fig. 7) result in better and reduced flame length, thereby reduce the flame impingement related issues.

WORKING OF THE INVENTION:
[0044] The Burner takes Fuel oil as input fuel and atomises it in the fuel oil gun located at the centre of the burner. In the same oil gun, there is provision for atomisation of air which properly atomises the fuel oil. The atomised fuel oil is ignited using the Gas pipe ignitor located near the centre of the burner. The required combustion for the initial start-up is provided in the form of primary air which is regulated manually through primary sleeves/dampers. As the load increases, fuel oil quantity increases and the combustion air requirement also increases, which is sent as secondary air through secondary sleeves /dampers. Primary air immediately surrounds the oil gun and secondary air is circumferential to the primary air. The burner can fire Fuel gas also. There is a gas chamber located at the front of the burner. Six separate gas lances originate from the gas chamber and terminate at the burner throat area. At the end of each gas lance, there is gas spud or Gas nozzle which directs the gas in a specified direction in a controlled manner. Then the gas mixes with secondary air and leads to further combustion and heat release.

[0045] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.

[0046] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.

[0047] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogues to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.

[0048] The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.

[0049] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.

[0050] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.

[0051] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

REFERENCE NUMERALS:

Figure 1 indicates the following:
01. Gas Chamber Front Plate Assy. 07. Sec. Swirler Outer casing
02. Pri. Air Drum Assy. 08. Secondary Air Shield Assly.
03. Sec. Swirler Assy. 09. Pri. Swirler Assy.
04. Pri. Shield Assy. 10. Burner Mounting Flange
05. Gas Lance. 11. Stabilizer Pate
06. Secondary Air Drum Assly. 12. Gas Ignior Guide Pipe Assly.

Figure 2 indicates the following:
01. Secondary Air Shield 04. Drive Assembly Top
02. Side Drive Assembly 05. Drive Assembly Bot
03. Stiffener Plate Top 06. Side Drive Assembly

Figure 3 indicates the following:
01. Pri. Air Sheild Plate 03. Top Roller Assly.
02. Slide Lug 04. Bottom Roller Assly.

Figure 4 indicates the following:
01. Pri. Air Drum 02. Roller Guide Assly.

Figure 5 indicates the following:
01. Air Drum 02. Roller Guide Assly.
, Claims:WE CLAIM:

1. An improved Low Nox oil and gas fired Burner comprises of Gas chamber [1], Primary air drum assembly [2], secondary air drum assembly [6], oil gun assembly, Gas pipe igniter assembly [12] and burner throat, wherein air from wind box enters the burner, is composed of said secondary air drum [6] with a secondary air swirler [3] and said primary air drum [2] with a primary air swirler [9]; wherein
the Gas chamber [1] is connected to multitude of gas lances [5], in which the gas lances [5] are connected to gas spud/nozzle;
said primary air drum [2] is connected to front portion of burner, in which primary shield assembly [4] covers said primary air drum [2] and primary shield assembly [4] moves on said primary air drum [2] forward/backward;
said secondary air drum [6] is connected to front portion of burner, in which secondary air shield assembly [8] covers said secondary air drum [6] and the secondary air shield assembly [8] moves on said secondary air drum [6] forward/backward.

2. The improved Low Nox oil and gas fired Burner as claimed in claim 1, wherein the secondary swirler assembly [3] is connected to secondary air drum assembly [6] and primer swirler assembly [9] is connected to the primary air drum assembly [2], in which the secondary swirler assembly [3] and primer swirler assembly [9] are provided in connection with stabilizer plate [11].

3. The improved Low Nox oil and gas fired Burner as claimed in claims 1-2, wherein secondary air sleeves are operated from the burner front by multiple power cylinders, in which by operating the power cylinder, the air sleeve is moved backward/forward, thereby changing the total amount of air admitted to the burner.

4. The improved Low Nox oil and gas fired Burner as claimed in claims 1-3, wherein a portion of the air entering the register is admitted as primary air to the primary air drum [2], in which the purpose of the primary air is two fold: To introduce air at the gun tip for initial combustion and to fill the vortex created by combustion in the secondary air zone.

5. The improved Low Nox oil and gas fired Burner as claimed in claims 1-4, wherein a gas plenum chamber is provided as a part of the front plate, in which the gas plenum ensures an even flow of gas to the multi lance gas burner arrangement, wherein the gas lances [5] are fitted with nozzles and are equispaced around the swirler.

6. The improved Low Nox oil and gas fired Burner as claimed in claim 1, comprising of roller Assembly arrangement in the Burner having single point contact between the roller and guide shaft.

7. The improved Low Nox oil and gas fired Burner as claimed in claims 1-5, wherein the stabiliser plate (11) is having less area compared to prevailing design which is exposed to continuous heating, and sufficient cuts and gaps are provided in the stabiliser plate that it takes care of the thermal expansions and cooling provision (allows the air to pass through it) without getting distorted.