ASSEMBLY AND METHOD FOR INJECTING A GASEOUS COMBUSTION AGENT

Abstract

An assembly for injecting a gaseous combustion agent into a combustion zone, the assembly having a chamber having an inlet, through which the agent is introduced into the assembly; at least one primary injector configured to convey a primary flow of the agent from the chamber toward the combustion zone, at least one secondary injector for conveying a secondary flow of the agent from the chamber toward the combustion zone, a pressure detector; a regulating; and a control system connected to the pressure detector and to the regulating system, the control system controlling the regulating system so that the flow section of the at least one secondary passage is regulated as a function of the pressure or of the variation in pressure detected by the pressure detector.

Claims

1.-15. (canceled)

16. An assembly for injecting a gaseous combustion agent into a combustion zone, which gaseous combustion agent is selected from gaseous fuels and gaseous oxidants, the assembly comprising: a chamber comprising an inlet, through which the agent is introduced into the assembly; at least one primary injector configured to convey a primary flow of the agent from the chamber toward the combustion zone and for injecting said primary flow into the combustion zone, said at least one primary injector being fluidly connected to the chamber by means of at least one primary passage; at least one secondary injector for conveying a secondary flow of the agent from the chamber toward the combustion zone and for injecting said secondary flow into the combustion zone, said at least one secondary injector being fluidly connected to the chamber by means of at least one secondary passage; a pressure detector for detecting a gas pressure or a variation in gas pressure in the chamber; a regulating system for regulating a flow section of the at least one secondary passage; and a control system connected to the pressure detector and to the regulating system, the control system controlling the regulating system so that the flow section of the at least one secondary passage is regulated as a function of the pressure or of the variation in pressure detected by the pressure detector.

17. The assembly as claimed in claim 1, wherein the control system is configured to control the regulating system so that the gas pressure in the chamber is located in a predetermined pressure zone or so that the gas pressure in the chamber corresponds to a value that is predetermined by regulating the flow section of the at least one secondary passage.

18. The assembly as claimed in claim 1, wherein the regulating system is provided with at least one valve configured to regulate the flow section of the at least one secondary passage.

19. The assembly as claimed in claim 1, comprising at least one pair of a primary injector with a secondary injector, in which pair one from among the primary injector and the secondary injector surrounds the other one from among the primary injector and the secondary injector.

20. The assembly as claimed in claim 1, comprising at least two primary injectors and/or at least two secondary injectors.

21. An installation comprising a plurality of assemblies as claimed in claim 1, the installation comprising a common control system that is connected to the pressure detector of each assembly and that is configured to control the regulating system of each assembly as a function of the gas pressure or of the variation in gas pressure detected by the pressure detector of said assembly.

22. A burner comprising an assembly as claimed in claim 1 for injecting a gaseous combustion agent into a combustion zone, which gaseous combustion agent is selected from a gaseous fuel and a gaseous oxidant, and at least one additional injector for injecting an additional fluid into the combustion zone.

23. The burner as claimed in claim 22, comprising a block with an inlet face and an outlet face opposite the inlet face, in which burner the assembly is attached to the inlet face of the block so that the injectors of the burner are positioned in one or more perforations passing through the block of the inlet face to the outlet face.

24. The burner as claimed in claim 23, wherein the primary and secondary injectors of the assembly form pairs of a primary injector with a secondary injector, the pairs being positioned in at least one first perforation of the block and the at least one additional injector being positioned in at least one additional perforation of the block.

25. The burner as claimed in claim 24, comprising at least two pairs and at least two additional injectors, wherein the pairs define a first injection plane for the fluid and wherein the injectors define a second injection plane for the additional fluid that is different from the first plane, the second plane being parallel to the first plane or being oriented so as to intersect the first plane in the combustion zone downstream of the outlet face.

26. A furnace comprising an internal combustion zone and comprising at least one assembly as claimed in claim 1 for injecting a gaseous combustion agent into the internal combustion zone of the furnace, which gaseous combustion agent is selected from gaseous fuels and gaseous oxidants.

27. The furnace as claimed in claim 26 comprising a plurality of assemblies, the furnace comprising a common control system that is connected to the pressure detector of each assembly and that is configured to control the regulating system of each assembly as a function of the gas pressure or of the variation in gas pressure detected by the pressure detector of said assembly.

28. A combustion method, wherein a gaseous combustion agent is injected into an internal combustion zone by means of an assembly as claimed in claim 1, which gaseous combustion agent is selected from gaseous fuels and oxidants, in which method: the pressure detector of the assembly detects the gas pressure in the chamber of the assembly; the system for regulating the assembly regulates the flow section of the at least one secondary passage; and the system for controlling the assembly controls the system for regulating the assembly so that the flow section of the at least one secondary passage is regulated as a function of the pressure or of the variation in pressure detected by the pressure detector of the assembly.

29. The method as claimed in claim 28, wherein the control system controls the regulating system so that the gas pressure in the chamber is located in a predetermined pressure zone or so that the gas pressure in the chamber of the assembly corresponds to a value that is predetermined by regulating the flow section of the at least one secondary passage of the assembly.

30. The method as claimed in claim 28, wherein the gaseous combustion agent is a gaseous fuel selected from natural gas, biogas, propane, butane, the residual gases of steel-making or methane-reforming methods, hydrogen or any mixture of at least two of these gaseous fuels, or is a gaseous oxidant with an oxygen content of 21 to 100 vol %.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0075] The invention and its advantages will be better understood in the light of the following examples: (with reference to FIGS. 1 to 5), in which:

[0076] FIG. 1 schematically shows an assembly comprising a primary injector (21) with a concentric secondary injector (22), the secondary injector (22) surrounding the primary injector (21);

[0077] FIG. 2 schematically shows an assembly comprising a primary injector (21) with a concentric secondary injector (22), the primary injector (21) surrounding the secondary injector (22);

[0078] FIG. 3 schematically shows an assembly comprising a primary injector (21) with a non-concentric secondary injector (22), separated by a distance;

[0079] FIG. 4 schematically shows a view of the assembly incorporated in a burner for injection of a gaseous combustion agent into a combustion zone (1).

[0080] FIG. 5 schematically shows a view of the assembly incorporated in a burner for injection of a gaseous combustion agent into a combustion zone (1).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0081] FIGS. 1, 2 and 3 show a fluid inlet chamber (11). The primary injector (21) is fluidly connected to the chamber (11) by means of a primary passage (23). The secondary injector is fluidly connected to the chamber (11) by means of a secondary passage (24). The secondary passage (24) has an adjustable flow section. A regulating system (32) allows this flow section of the secondary passage (24) to be regulated by virtue of a valve (33).

[0082] FIGS. 1, 2 and 3 also show a pressure detector (30) for detecting a gas pressure or a variation in gas pressure in the chamber (11), as well as a control system (31) connected to the pressure detector (30). The control system is also connected to and controls the regulating system (32).

[0083] FIG. 4 schematically shows an assembly comprising three primary injectors (21) each surrounded by its concentric secondary injector (22), and a chamber (11).

[0084] The primary injectors (21) are fluidly connected to the chamber (11) by the primary passages (23). The secondary injectors (22) are fluidly connected to the chamber (11) by the secondary passages (24). The secondary passage has an adjustable flow section. A regulating system (32) allows this flow section of the secondary passage (24) to be regulated by virtue of a valve (33). A pressure detector (30) is present for detecting a pressure or a variation in gas pressure in the chamber (11). A control system (31) is connected to the pressure detector (30). This control system is also connected to and controls the regulating system (32).

[0085] In FIGS. 4 and 5, the burner comprises a block (40) with an inlet face (41) and an outlet face (42) opposite the inlet face, as well as additional injectors (50) for injecting an additional fluid into the combustion zone (1).

[0086] The automatic regulation by the feedback system according to the present invention advantageously can be implemented in various combustion methods, such as for glass production.

[0087] The glass production furnaces mainly use air preheated to over 1000° C. as an oxidant. This hot air is obtained by passing through regenerators (stack of refractory bricks). The amount of oxidant injected into the furnace at this temperature level involves a significant amount of movement.

[0088] During the campaign of a furnace, production may need to be increased beyond the capacity of the regenerators, which cannot provide a greater amount of hot air due to the limitation of the draw of the fans. A similar problem occurs when the state of the bricks does not allow or no longer allows the desired preheating temperatures to be obtained.

[0089] The burner installation operating with an oxygen-rich oxidant (oxy-burner) then appears to be a particularly suitable solution. These burners are generally installed in the openings available dose to the regenerators. With the oxy-combustion (i.e. combustion with an oxidant containing at least 80 vol %, and preferably at least 90 vol %, of oxygen) generating an amount of smoke that is 4 times lower than air combustion and with at least equivalent efficiency, the flames originating from oxy-burners, hereafter called “oxy-flames”, are severely disrupted by the flames, called “aero-flames”, originating from regenerators operating with hot air, due to the lower amount of movement of the oxy-flames. These disruptions can lead to the oxy-flame interfering with the molten solid material and unburnt materials and thus to glass quality or energy efficiency problems. These problems are even more significant when the power (and therefore the flows of the combustion agents) of the oxy-burners is reduced for lower increased production phases. It is therefore essential to maximize the pulse or the amount of movement of the oxy-flames throughout the entire power range of the oxy-burners.

[0090] Systems, such as those described in document EP 2143999, allow manual regulation of the flow of gaseous fuel between two injections (primary and secondary) in order to maximize the pulse of the fuel and thus ensure the stability of the flame of the oxy-burner. However, these manual systems require constant adjustment of the fluid distribution by the operators, without being able to easily assess the impact of these adjustments on the method in real-time. In order to avoid these adjustments and any quality problems, the operators most often adjust the power on the air burners (regenerator), causing excessive oxygen consumption and an increase in the production costs.

[0091] The present invention advantageously can be used in this case by defining a predefined pressure range or a predefined pressure allowing automatic distribution to be ensured of the flow between the primary and secondary injections, so as to maximize the pulse of the oxy-flame irrespective of the total flow of fuel,

[0092] For example, in the case of a 4% production increase, the power of an oxy-burner can be 800 kW, whereas for an 8% oxygen increase, the power of an oxy-burner can be 1.8 MW. It has been determined that a pressure of 300 mbarg in the distribution chamber between the two fuel injections allows a highly stable flame to be provided both at 800 kW and at 1800 kW. The automatic regulation, according to the invention, of the distribution of the fuel, as a function of the gas pressure in the chamber when the power varies, will thus allow the production costs to be optimized, quality defects to be limited and energy consumption to be optimized.

[0093] It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. Thus, the present invention is not intended to be limited to the specific embodiments in the examples given above.