Title of Invention

AN IMPROVED GAS FIRED BURNER MODULE

Abstract

The present invention is directed to an improved gas fired burner module having a number of vertical cylindrical tubes for supplying fuel gas in conjunction with a gas header and a gas inlet, a number of co-axially disposed vertical cylindrical primary air tubes around the said gas tubes arranged in a straight line for supplying primary air in conjunction with an air header and an air inlet. The leading end of the gas tubes being surrounded by a set of air swirlers, there being a refractory or metallic block at the tip end of the burner module which is provided with secondary air slits; A fuel burner system having a plurality of said burner modules and an improved process for igniting the top layer of a sinter bed using said system.

Full Text

The present invention relates to an improved gas fired burner and a curtain type burner systems having a plurality of said burners and a method of sintering top layer of raw material fines and fuel fines in a sintering process. The improved burner according to this invention is used for igniting the moving top layer in of sinter bed in sintering process by advantageous and efficient burning with a curtain type top mounted gas fired burner system for igniting top layer of a sinter bed. PRIOR ART It is well known to use gas-fired burners for igniting the top layer in a sinter bed. A conventional burner consists of number of side turbulent type of burners, located on two sides of ignition furnace. Burners heat up the furnace and its refractory mass. Heat transfer from furnace to sinter bed takes place mainly through radiation. Lot of heat is wasted to the atmosphere through the walls of the larger furnace. In a conventional process of igniting the top layer of a sinter bed the following procedure is followed. Flame from burner heat up the refractory mass inside the furnace primarily by radiation, which in turn transfer major part of the heat to the top layer of sinter bed through radiation. A minor part of the heat is also transferred to the top layer of sinter bed by convection when the low temperature combustion products are sucked through the bed after releasing major part of its energy through radiation. DRAW BACK OF THE PRIOR ART It has been found that the fuel consumption is very high during the normal running of the machine. Another drawback is that heat load required is considerable high to keep the furnace warm during machine switched off condition. Another drawback is that the construction and maintenance cost of furnace is exorbitant. Yet another drawback is the furnace's length for sinter ignition is considerable. This decreases the remaining length of the furnace strand available for sintering thereby increasing investment cost and also product cost. The conventional process and the conventional burner are therefore not energy efficient and economical. OBJECTS OF THE INVENTION It is thus the basic object of the invention to obtain an improved gas fired burner for providing efficient burning of the fuel gas than before. A further object of the invention is to provide a burner, which can be custom made. A still further object of the invention is to provide such a burner which can be easily mounted or dismantled and also can be easily cleaned whenever required. A still further object of the invention is directed to an improved burner, a plurality of which can be aligned to form an assembly of burners in a single row on the roof of a low height small furnace. According to yet another object of the invention directed to obtain an improved burner system having a plurality of improved burners which can create a continuous curtain type flame wherein the flame directly impinges uniformly on the top layer of the charge on the sinter bed. A still further object of the invention is to obtain an improved process for igniting top layer of a sinter bed by using the improved burner system such that the top layer of the charge on the sinter bed derives heat required to ignite the top layer mainly by convection. BRIEF STATEMENT OF THE INVENTION The basic aspect of the present invention is thus directed to an improved gas fired burner module comprising of a number of vertical cylindrical gas tubes arranged in a straight line for supplying fuel gas in conjunction with a gas header and a gas inlet, a number of co- axially disposed vertical cylindrical primary air tubes around the said gas tubes arranged in a straight line for supplying primary air in conjunction with an air header and an air inlet. The leading end of the gas tubes being surrounded by a set of air swirlers and there being a refractory or metallic block at the tip end of the burner module which is provided with secondary air slits. The air header extends from and covers the gas tube exteriorly from the trailing end. The portion of the gas tube uncovered by the air header is provided with a cylindrical annular space having primary air swirlers. The said annular space is formed between an outer primary air tube and the leading end of the cylindrical gas tube. The above said outer primary air tube is covered by a refractory or metallic block extending to the required length forming the tip end of the burner module. The refractory or metallic block has a first internal cylindrical section followed by a divergent section forming the tip end of the burner module. The outer vertical surface parallel to the plane joining the axes of the gas/air tubes of the entire refractory or metallic block is provided with a secondary air slits. According to another aspect of the invention there is provided an improved burner system having a plurality of the above said improved burner modules mounted in an assembly in a single row on the top end of a low height small furnace. According to yet another aspect of the invention there is provided an improved process for igniting the top layer of a sinter bed involving said burner system, which comprises impinging upon the top layer of the charge of the sinter bed with a continuous curtain type flame generated by said burner system, thereby giving the heat required to top layer mainly by convection. The said top layer is made of a moving bed of a mixture of raw material fines and solid fuel fines as required. The present invention and its objectives and advantages are described in further details with reference to the accompanied drawing: DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURE: BRIEF DESCRIPTION OF THE FIGURE: Figure 1 : shows the cross-section of an improved burner module of the invention. Referring to the drawing it can be seen that each burner consists of a vertically erected central tube for supplying fuel gas (1) a concentric outer tube with swirlers for supplying primary air (2) and an outer jacket with small apertures called slits one at each lateral side of the burner for supplying secondary air (3). A number of burners are assembled in one unit called burner module. Individual pipes supply fuel gas & air to each module. The gas header (4) and air header (5) for distribution of the same to each burner have been made compact and incorporated inside the burner module. In order to anchor the flame, to provide sufficient mixing between fuel, gas & primary air and to make the flame generated by individual burners overlap and form a continuous flame, a burner block (metallic/refractory) (6) is provided at the tip of the burner. If the flame length requirement of the burners changes from one Application to another, the burner design can be modified to distribute primary and secondary air inside the burner accordingly. To ease mechanical cleaning of the gas tube, an aperture (7) covered by a lightweight blank flange bas been provided at the top of the gas tube of each burner. The burner system creates a continuous curtain type flame where the flame directly impinges uniformly on the top layer of the charge thereby giving the heat required to ignite the top layer mainly by convection. Advantages of the invention 1. Reduction in fuel consumption by more than 35% during normal running of the machine. 2. Total elimination of the « 30% heat load required to keep the conventional furnace warm during machine stoppages. 3. Saving in furnace cost by more than 85%. 4. Availability of more strand length for sintering as the furnace length is reduced by « 75%. This can be utilized in increasing the production from the machine by increasing the machine speed. We claim: An improved gas fired burner module comprising of a number of vertical cylindrical gas tubes arranged in straight line for supplying fuel gas in conjunction with a gas header and a gas inlet, a number of co-axially disposed vertical cylindrical primary air tubes around the said gas tubes arranged in a straight line for supplying primary air in conjunction with an air header and an air inlet, the leading end of the gas tubes being surrounded by a set of air swirlers and there being a refractory or metallic block at the tip end of the burner module provided with secondary air slits. An improved gas fired burner as claimed in claim 1, wherein the air header extends from and covers the gas tube exteriorly from the trailing end. An improved gas fired burner as claimed in claims 1 and 2 wherein the portion of the gas tube uncovered by the air header is provided with a cylindrical annular space having primary air swirlers. An improved gas fired burner as claimed in claims 1 to 3 wherein the said annular space is formed between an outer primary air tube and the leading end of the cylindrical gas tube. An improved gas fired burner as claimed in claims 1 to 4 wherein the above said outer primary air tube is covered by a refractory or metallic block extending to the required length forming the tip end of the burner module. An improved gas fired burner as claimed in claims 1 to 5 wherein the refractory or metallic block has a first internal cylindrical section followed by a second divergent section forming the tip end of the gas burner and the outer vertical surface parallel to the plane joining the axes of the gas/air tubes, of the entire refractory or metallic block is provided with a secondary air slits. An improved burner system having a plurality of the improved burner modules as claimed in claims 1 to 6 mounted in an assembly in a single row on the top end of a low height small furnace. An improved process for igniting the top layer of a sinter bed involving the burner system as claimed in claim 7 which comprises impinging upon the top layer of the charge of the sinter bed with a continuous curtain type flame generated by said burner system thereby giving the heat required to top layer mainly by convection. An improved process for igniting the top layer of a sinter bed as claimed in claim 8, wherein the said top layer is made of a moving bed of a mixture of raw material fines and solid fuel fines as required. An improved gas fired burner and process for igniting top layer of sinter bed involving the same substantially as herein described with reference to the accompanying drawing. The present invention is directed to an improved gas fired burner module having a number of vertical cylindrical tubes for supplying fuel gas in conjunction with a gas header and a gas inlet, a number of co-axially disposed vertical cylindrical primary air tubes around the said gas tubes arranged in a straight line for supplying primary air in conjunction with an air header and an air inlet. The leading end of the gas tubes being surrounded by a set of air swirlers, there being a refractory or metallic block at the tip end of the burner module which is provided with secondary air slits; A fuel burner system having a plurality of said burner modules and an improved process for igniting the top layer of a sinter bed using said system.

Documents:

600-CAL-2002-(02-02-2012)-FORM-27.pdf

600-CAL-2002-CORRESPONDENCE 1.1.pdf

600-CAL-2002-CORRESPONDENCE.pdf

600-CAL-2002-FORM 27 1.1.pdf

600-CAL-2002-FORM 27.pdf

600-cal-2002-granted-abstract.pdf

600-cal-2002-granted-claims.pdf

600-cal-2002-granted-correspondence.pdf

600-cal-2002-granted-description (complete).pdf

600-cal-2002-granted-drawings.pdf

600-cal-2002-granted-examination report.pdf

600-cal-2002-granted-form 1.pdf

600-cal-2002-granted-form 13.pdf

600-cal-2002-granted-form 18.pdf

600-cal-2002-granted-form 2.pdf

600-cal-2002-granted-form 3.pdf

600-cal-2002-granted-pa.pdf

600-cal-2002-granted-reply to examination report.pdf

600-cal-2002-granted-specification.pdf