MXPA00010090A - Method and apparatus for backing-up oxy-fuel combustion with air-fuel combustion - Google Patents

Abstract

An air-fuel burner (42) is used to maintain an operating temperature in a furnace normally heated with an oxy-fuel burner when the supply of oxygen is temporally reduced or stopped. Preferably, both the oxy-fuel burner and the air-fuel burner mount to a common pre-combustor (14) having a first passage (26) and a separate second passage (32) disposed beneath and coextensive with the first passage (26). When using the oxy-fuel burner, the oxy-fuel flame is directed through the first passage (26) and additional oxygen is directed through the second passage. When using the air-fuel burner, air or oxygen-enriched air is directed through the first passage (26) and fuel is separately directed through the second passage (32). Water cooling of the furnace gases can be used to reduce the volume of exhaust gases when operating with the air-fuel burner.

Description

METHOD AND APPLIANCE FOR SUBSTITUTING A FUEL COMBUSTION WITH OXI FOR A COMBUSTION OF FUEL WITH AIR RECIPROCAL REFERENCE TO RELATED REQUESTS Not applicable DECLARATION RELATED TO THE INVESTIGATION AND DEVELOPMENT SPONSORED BY THE FEDERATION Not applicable BACKGROUND OF THE INVENTION The present invention relates to the methods for oxy fuel and the devices for producing high temperature in industrial melting furnaces for various products such as metals, glass, ceramic materials and the like. In particular, the present invention relates to combustion and methods and apparatuses for the continuation of combustion in the event that the availability of oxygen for the oxy fuel process is reduced or terminated. The use of oxy fuel burners in industrial processes such as glass melting, allows the furnace designer to achieve a varied flame momentum, glass melting coverage and flame radiation characteristics. Examples of such burners and combustion processes are described in U.S. Patents. Nos. 5,256,058, 5,346,390, 5,547,368 and 5,575,637 the disclosures of which are incorporated herein by reference. A particularly effective process and apparatus for utilizing oxy fuel combustion in the manufacture of stage combustion related to glass, which is disclosed in U.S. Pat. No. 5,611,682, the specification of which is incorporated herein by reference. In the early 1990s, glassmakers began converting combustion furnaces from air to oxy fuel combustion. The oxygen enrichment in some air fuel systems has been achieved where the oxygen concentration was increased up to 30%. Higher oxygen concentrations in the range of 40% to 80% are not used due to the potential increase in the formation of Nox contaminants. It has also been found that using oxy-fuel where oxygen is present in a concentration between 90% and 100% results in a more favorable economic aspect for the user. Many of the large glass oxy fuel furnaces are supplied by oxygen generated at the site using well known vacuum oscillating cryogenic adsorption techniques. It is common, and to date, the only method to support the oxygen supply generated at the site is to maintain a liquid oxygen inventory at the same site. So when the on-site generation facility is a pipeline withdrawn from service either due to a process problem or routine maintenance, the inventory of the liquid oxygen is used to supply the oxygen for oxy fuel combustion. This method to support the oxygen generated at the site requires large insulated tanks to store oxygen in a liquid form and vaporizers to allow liquid oxygen to be converted to gaseous oxygen for use in the process for an oxy fuel. It is conventional to use trucks to transport liquid oxygen to the site in a large facility for air separation. Using the liquid oxygen substitute with an oxygen system generated at the site allows the user to continue using a process for an oxy fuel without interruption. Any fuel combustion system with oxy, for example one of those disclosed in the patents mentioned above, will benefit on-site production having a substitute system. Until now, the support of oxy fuel furnaces with a liquid oxygen inventory has not been considered a problem. However, with the conversion of more and more furnaces in sites with multiple furnaces and the use of oxy fuel combustion in flat or floating glass furnaces that are much larger and use more oxygen, the support of liquid oxygen will become a significant problem for the user due to the high capital cost of storage tanks and vaporizers. In addition to the cost issue, a logistical problem arises related to the transport of liquid oxygen to the site and that it has enough liquid oxygen available with little notice time from a nearby air separation facility used to produce liquid oxygen. The transport of liquid oxygen to user sites in remote locations will become a major problem with freight with greater difficulties. Normally, when the glass furnace is converted from fuel to air with oxy fuel, heat recovery devices such as regenerative and air supply systems are removed. For the user, one of the incentives to convert the fuel with oxy is to reduce the capital costs due to the elimination of the heat recovery devices. Due to the design of oxy fuel burners, the furnace can not be operated by simply replacing air with oxygen in conventional combustion systems in current use. The pressure requirement to provide an equivalent amount of contained oxygen, using air in an oxy fuel burner will be extremely high, which requires an expensive air supply system.

In addition, some oxy fuel burners are of limited sonic flow type, in case they are ignited at an equivalent ignition speed. When oxy fuel combustion is used where the oxygen supply is reduced or interrupted, the conventional technique is to keep the furnaces in a condition called "heat maintenance". The maintenance of heat is a condition where production is stopped and the oven is kept warm so that the glass does not solidify. Allowing the glass to solidify would severely damage the ovens. Several companies specialize in reheating the furnace after the repairs of cold furnaces. They use a specially designed air fuel burner to provide the initial increase in furnace temperature. In the event of an interruption of the oxygen supply, the same burners can be used to provide sufficient heating for the maintenance of the heat. In this procedure, a special temperature profile for production will not be attempted and the maximum temperature achieved by these devices can be approximately 1192.40 ° C (2200 ° F). This temperature is not sufficient for the production of glass and is at least the preferred option to be used by glass manufacturers. The cost of not producing glass is very high for the glass manufacturer, in terms of the sales losses of the products, as well as the interruption of the glass formation lines downstream. Therefore, there is a definite need to provide a method and apparatus for maintaining production in a furnace used for the manufacture of glass in the case of a withdrawal or interruption in oxygen availability. BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for replacing a fuel combustion system with oxy by an air fuel combustion system that can be used with or without oxygen enrichment to maintain production in a industrial furnace, such as a glass melting furnace. In accordance with the present invention, a system has been invented, which allows operation in a fuel mode with oxy and fuel with air or a fuel mode with air enriched with oxygen. The burner according to the present invention has a unique feature related to the very low speed operation for the oxy fuel mode which allows a drop in acceptable pressure through the burner when operating in an air fuel mode. A burner according to the present invention can utilize the oxygen enrichment to effect the process.

In accordance with the present invention, a conventional burner block such as that described in U.S. Pat. No. 5,611,682 can be used either for combustion of fuel with oxy or combustion with air, allowing the combustion system to be rapidly converted between the two modes. In accordance with the present invention, when a problem occurs with the oxygen supply, the oxy fuel burners will be turned off, disconnected and replaced by the substitute air fuel burners having the same configuration for a connection with the burner block. With the substitute air fuel system, the user will retain the air supply systems of the previous air fuel systems used in the casting operation or, by means of air blowers that will be supplied as part of the substitute system. Air fuel burners in accordance with the present invention will be able to ignite at speeds substantially greater than oxy fuel burners. So, in one aspect of the present invention it is a process for maintaining the heating of a furnace at an elevated temperature employing oxy fuel combustion., wherein a flame is introduced into said furnace and an oxidant is introduced under said flame, when the oxygen supply for said flame and said oxidant is removed or it is completed comprising the steps of replacing the flame with an air or flame. air enriched with oxygen introduced at a rate to maintain approximately the ignition speed of the burner when oxygen is the only oxidant source for combustion, and replace the oxidant introduced under said flame with said fuel to provide combustion and maintain said temperature at said oven. In another aspect, the present invention is a combustion system of the type having a fuel burner with oxi adapted to produce a flame with a pre-combustion chamber mounted on the burner, the pre-combustion chamber having a first passage with a first end in a fluid-tight relationship with one end of the flame of the burner and a second end adapted to direct the flame produced by the burner heating in industrial environments in a configuration similar to a generally flat fan and a second passage in the pre-combustion chamber disposed below the first passage and coextensive therewith, the second passage ends at the nozzle end at the second end of the pre-combustion chamber to direct the oxidation fluid beneath the flame and generally parallel to the The improvement includes: a first element for introducing fuel with air or air enriched with oxygen through the burner inside the pre-combustion chamber in the place of the flame and a second element to introduce fuel into the second separated passage in the pre-combustion chamber in the place of the oxidation fluid, whereby the combustion system can continue heating the industrial environment in the event that the air supply is interrupted or reduced. In still another aspect, the present invention contemplates reducing the volume of exhaust gas in an oven that is heated according to the method and apparatus of the invention by cooling the exhaust gases leaving the oven with liquid water. Yet another aspect of the present invention relates to the replacement of combustion of air with fuel combustion with oxy to maintain heating in an industrial environment, air or oxygen enriched air that is introduced into the environment of any form so that there is sufficient volume to effect the required level of heating. In this aspect the cooling of the exhaust gases with liquid water will be beneficial to reduce the volume of the exhaust gases. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic perspective view of a conventional stage combustion apparatus.

Figure 2 is a view taken along line 2-2 of Figure 1. Figure 3 is a schematic perspective view of an apparatus according to the present invention. Figure 4 is a front view of the burner block or pre-combustion chamber of the apparatus of Figure 3. Figure 5 is a graph of the percentage of normalized methane flow compared to the percentage of normalized oxygen flow for conditions of a zero production to a total production. Figure 6 is a graph of the oxygen concentration compared to the percentage of normalized oxygen flow for the production percentages of Figure 5. Figure 7 is a graph of the percentage of normalized gas outlet flow compared to the percentage of normalized oxygen flow for several production percentages. Figure 8 is a graph of the percentage gas flow normalized after dilution with air compared to the percentage of oxygen flow for the percentages of production between zero production at maximum production. Figure 9 is a graph of the percentage of normalized outlet gas flow after dilution with water compared to the percentage of normalized oxygen flow for kiln production from zero production to maximum production. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for replacing a fuel heating system with oxy by a fuel heating system with air. According to the invention, the fuel-air substitute system can be operated with or without oxygen enriched air. The burner according to the invention allows at least two different modes of operation, for example, the fuel mode with oxy or the fuel mode with air. Another characteristic of the burner is the operation at a very low speed for the fuel mode with oxy, thus allowing acceptable pressure drops through the burner when operating in the fuel mode with air with or without enriching the air with oxygen. For the purposes of this invention combustion of fuel with oxy means a combustion with 80% to 100% by volume of oxygen. Oxygen enrichment means between 22% to 80% by volume concentration of oxygen. According to the invention, the same burner block or pre-combustion chamber can be used during any fuel operation with oxy or fuel with air, allowing the combustion system to be more rapidly converted from one mode to the other. In the case where an operator encounters a problem with the oxygen supply, the oxy fuel burners will be turned off, disconnected and replaced with the substitute fuel burners with air having the same connection as that of the burner block. With a substitute fuel-air system, a glass manufacturer will retain their air supply systems present prior to the conversion to fuel combustion with oxy, or by blowers that will be supplied as part of the substitute system. It is important that the substitute burners be able to ignite at a substantially higher speed than that of the oxy-fuel burners that are replaced. A higher ignition speed is required for the fuel substitute burner with air due to additional energy losses caused by heating and nitrogen being expelled. Also, the air used for combustion in a substitute system will typically not be preheated, which results in a decrease in the efficiency of the furnace relative to a typical air fuel furnace. A simplified thermodynamic calculation illustrates the need to increase the ignition speed with the fuel when air that is not previously heated for combustion is used. The assumptions for this example are: fuel and oxygen react completely without excess oxygen and without intermediate products that over; and all the gases escape from the furnace at 1522.40 ° C (2800 ° F) after finishing the combustion. Under these conditions, 2.65 times the ignition speed is required when ignited with air compared to ignition with 100% oxygen in order to maintain the same heat available. The available heat is the energy transferred to the load and the heat loss from the oven. So the total percentage of oxidizing volumetric flow will increase dramatically when the percentage of oxygen flow is reduced. The volume of the oxidant stream is increased by a factor of 4.76 due to the addition of nitrogen and an additional 2.65 times due to the requirement of a higher ignition speed. This means that the flow rate of the oxidant stream increases approximately 12.6 times when the air is completely replaced by oxygen. A major concern when using a combustion of air in a fuel burner assembly with oxy is the air supply pressure required to accommodate larger gas volumes needed. The present invention uses a system of a low speed oxidant. So even when igniting in an air fuel mode, the pressure drop is quite low to allow the use of relatively inexpensive air blowers, while maintaining the burner ignition speeds equal to or greater than those used with the oxy fuel. This, in turn, allows the continuity of production when a user, for example, a glass melter, is operating in the substitute mode during an emergency due to the loss or reduction of the oxygen supply. Oxy fuel burners with oxidizing speeds greater than approximately 27.43 m / sec. (90 ft / sec.) At any point of the burner, the design will be of the sonic type limited to an equivalent ignition speed, when the air is used as the oxidant for maximum production. The sonic velocity is defined by the equation a = cRTX where k is the proportion of specific heats (1.4 for air), R is the gas constant (287 J / kg K), and T is the absolute temperature. For air at 25 ° C (77 ° F), the sonic velocity is 346 m / sec. (1135 ft / sec.). For a fuel burner with oxy with an oxygen speed of 30.48 m / sec. (100 ft / sec.), The equivalent flow rate that the air uses will be 12.6 times the amount or 384.04 m / sec. (1260 ft / sec.) Which is greater than the sonic velocity. Therefore, to avoid a sonic limit, the oxy fuel burner should be designed with an oxygen velocity of less than 27.43 m / sec. (90 ft / sec.), If a full air replacement for oxygen is used without changing any part of the burner assembly. Alternatively, this limit can be avoided according to an aspect of the invention wherein the burner body is changed when switching between modes of operation. The burner block must be designed so that the surface velocity is less than the sonic velocity for the operation of fuel with air. The shape of the flame is also a concern of traditional oxy fuel burners that operate 2.65 times their estimated ignition speed, especially with 1.2 times the volumetric flow rate through the oxidizing passage. The embodiment of the invention disclosed below provides a flame form suitable for both fuel operating modes with oxy and fuel with air. So according to the invention, the concerns related to the oxidant supply pressure, the speed limits and the shape of the flame are overcome in accordance with the present invention, we have found that it is possible to allow a user to change a ignition with oxy fuel to an air fuel ignition using the same burner block, by modifying the burner body of a Cleanfire® HR ™ burner commercially available from Air Products and Chemicals Inc. of Allentown Pennsylvania. With reference to Figure 1, a step combustion apparatus 10 includes a fuel burner with oxy 12 and a pre-combustion chamber or burner block 14. The fuel burner with oxy 12 includes a central conduit 16 for receiving a fuel such as natural gas, which is indicated by the arrow 18. An oxygen source indicated by an arrow 20 is inserted into a passageway between the fuel conduit 16 and the outer concentric conduit 22. The burner is described in detail in the US Pat. 5,611,682, the specification of which has been incorporated herein by reference. The burner 12 fits in the burner block 14 and is maintained in a fluid-tight relation thereof at a first end 24 of the pre-combustion chamber or the burner block 14. Burner block 14 contains a first passage or central passage 26, which extends from the first end 24 to the discharge end 28 of the burner block 14. The passage 26 has a width greater than its height and has a divergent configuration as shown and described in the patent No. 5,611,682. In order to have a stepwise combustion, the graduated oxygen represented by the arrow 30 is introduced into a second passage 32 in the burner block 14. The passage 32 has a configuration complementary to that of the central passage and has a width greater than its width. height as illustrated and described in detail in the patent No. 5,611,682. With reference to Figure 2, at the first end 24 of the pre-combustion chamber 14, the oxy-fuel fuel burner 12 has a discharge end with a central fuel conduit 16 surrounded by an oxygen passage 22. Oxygen Graduated to a passage 31 that is disposed below the passage of the fuel flare with oxy as shown in Figure 2. Figure 3 shows the combustion apparatus according to the present invention. The combustion apparatus 40 includes a burner block 14, which is identical to the burner block 14 of Figure 1. In accordance with the present invention, the burner 42 is similar to the oxy fuel burner 12 of Figure 1 with a device 44 to allow the introduction of oxygen enriched air or air into the upper passageway of the burner 42. The burner 42 is also adapted to introduce air or oxygen enriched air through the passage 48 of the burner 42 into the upper passage 50, where the oxidizer of passages 44 and 48 is mixed, Arrow 46 represents the introduction of air or air and oxygen into device 44 which in turn introduces air or air enriched with oxygen within passage 50. Air or air enriched with oxygen it moves from the passage 50 within the central passage 26 of the burner block and exits to the furnace. When the burner is converted back to an ignition with fuel with limited oxy or a ignition that is not with oxy fuel, the oxygen supply graduated (indicated by the arrow 30 in Figure 1) is replaced by fuel, represented by the arrow 54. so that the fuel or fuel enriched with oxygen leaves the passage 32 of the burner block 14. Schematically shown in Figure 4 are the passages 26 and 32 at the front end of the burner block 14 with the passage 26 that is used for introducing air or oxygen enriched air into the furnace and passage 32 which is used to introduce fuel or oxygen enriched fuel into the furnace. When the burner 42 is used in the ignition mode with fuel with air, the air or oxygen enriched air flows through the passage 26 and the fuel or fuel enriched with oxygen flows through the passage 32. The designed burner block is such that a fuel flame with stable air is established due to the recirculation region between the two openings. In addition to the ignition speed with the fuel with air, the device of the present invention allows the variation of the degrees of oxygen enrichment to be achieved. The use of oxygen enrichment improves the flexibility during operation in the substitute mode by decreasing the use of oxygen supplied from the storage of liquid oxygen. It also allows the adjustment of the length of the flame by adding oxygen to the air flow. Supplemental oxygen can be supplied by various methods. For example, the air can be enriched with oxygen, the oxygen lancets can be supplied through any primary passage 26 or through both primary passages 26 of the pre-combustion chamber 14 or the graduated gate 32 or the separated oxygen lancets can to be installed at a distance away from the pre-combustion chamber 14 or the damper 32. By using the method and apparatus of the present invention it is possible to maintain a maximum temperature and distribution temperature necessary for the production of glass. Oxygen enrichment or ignition with oxy fuel will preferably be used in burners with higher ignition speeds near the extreme heating regions. This reduces the speed of the air flow required for these burners and reduces the pressure drop. Also the oxygen enrichment increases the maximum temperature of the flame and thus increases the heat transfers in the region of extreme heating. It is well known that an extreme heating region is required for glass manufacturing furnaces, to establish an adequate transmission of the cells in the foundry of the glass that is required to produce glass of acceptable quality. Other fuel technologies with air can be used to maintain extreme heating conditions. This invention is intended to allow the user to continue production. The minimum ignition speed provided by the substitute system of a fuel with air is such that at least 20% of the proportion of the designed production can be maintained. It is considered that this production capacity is sufficient to allow a producer of floating glass to maintain continuous strips of glass in the floating baths. Fuel burners with higher speed oxy can be modified for low speed operation by adding one or more gates to use the technology disclosed herein. These inputs can be closed normally or used to graduate the operation during operation with oxy fuel. Also one or more additional inlet gates may be added in the gear before initiating the replacement of the fuel with air by drilling a hole in the refractory wall in a closed location of the burner damper. Another alternative for ovens that use high-speed burners is to replace the burner blocks with blocks that have larger openings to reduce the fall pressure. With this method there is a danger of introducing foreign refractory material into the glass melt during the replacement procedure which can cause defects in the glass. In addition, the replacement of the burner blocks in the march requires a substantial time, possibly quite long to avoid the interruption of production. Figure 5 shows the percentage of methane flow required for the conditions of heat maintenance (at a zero production capacity), for production conditions of 20%, 50% and maximum production, assuming, for example, that 35% of the Available heat is required for the heat losses of the kiln wall under the conditions of maximum production. Heat maintenance can be achieved with lower ignition speeds than those shown in the graphs since the entire furnace temperature would be reduced, thus reducing heat losses from the furnace wall. This graph assumes that the heat losses remain the same, independent of the production capacity or the use of oxygen. The percentage of methane flow is normalized based on the percentage of methane flow for maximum production with 100% oxy fuel and the percentage of oxygen flow is normalized based on the percentage of oxygen flow for maximum production with 100% fuel with oxy. The percentage of normalized oxygen flow is 1.0 when all the oxidant for combustion is supplied by the oxygen source (other than air) and zero when all the oxidant for combustion is supplied by the air. Figure 6 is a graph that corresponds to the concentration of oxygen as a function of the percentage of normalized oxygen flow for each of the production percentages shown in Figure 5. As indicated in point A of Figure 5, to maintain heat using only air as the oxidant for combustion (at a zero percentage of normalized oxygen flow), the percentage of methane flow is approximately equal to that required with 100% of the oxy fuel for maximum production ( the normalized value is equal to 1). The maintenance of heat can also be maintained with a percentage of 35% of oxygen flow for maximum production with 35% percentage of methane flow for maximum production (point B). With reference to Figure 6 (point B), the operating condition represented by point B corresponds to 100% fuel with oxy without air dilution. Figure 5 shows that the percentage of oxygen flow and the percentage of methane flow can each be reduced by half to produce 20% of maximum production. This means that if the production is limited to 20% of the maximum production capacity, the stored oxygen supply can last for twice as much. In accordance with Figure 6, this corresponds to 100% ignition with the oxy fuel. At a production of 50%, the percentage of oxygen flow can be reduced to half the maximum production flow capacity and methane at approximately 95% of the maximum production flow capacity, according to Figure 6, The oxygen concentration for this operation condition will be about 35%. The outlet gas temperature of the fuel furnace with oxy is higher than the corresponding temperature for the fuel furnace with air after the heat recovery device. The manufacturers of glass, therefore, must decrease the temperature of the products and combustion of fuel with oxy by some shouting methods that the gases enter the sections of the d-e system d >; μctos manufactured with metal. Due to current air pollution, the treatment of fuel gas for glass furnaces typically includes particulate removal devices, such as electrostatic precipitators or large bag chambers. These devices have a maximum operating temperature significantly lower than the oxy fuel outlet temperatures, typically around 532.40 ° C (1000 ° F). Therefore, the exhaust gases must be cooled by a dilution of cold air (at room temperature) before these devices. In case the air is replaced by oxygen for combustion in an oven designed for combustion of fuel with oxy, the output volume will increase substantially. Figure 7 shows the manner in which the percentage of outflow is increased when the air is replaced by oxygen for various production percentages. The same assumptions related to the inlet and outlet temperatures and the heat losses used for the previous quantities are used to generate this amount. The percentage of outflow is normalized in relation to the percentage of outflow for maximum production with 100% of the fuel with oxy. For maximum production, the percentage of outflow will increase by more than nine times if the oxygen is completely replaced by air. More than three times the percentage of outflow can be expected at the expected extreme heating conditions where the air is completely replaced by oxygen. As a result of the increased flow of hot exhaust gases, much more dilution of the air must be provided to lower the temperature to the same level before the gases enter the metal section of the duct system. Figure 8 shows the result of the thermodynamic calculations, where the kiln's exhaust gases at 2,522.40 ° C (2800 ° F) are diluted with air at 25 ° C (77 ° F) to produce a gas stream at 532.40 ° C (1000 ° F), which is a suitable temperature for the metal section of the duct system. The percentage of normalized outflow after dilution with air is plotted as a function of the percentage of normalized oxygen flow. The outflow is normalized to 100% fuel with oxy, the maximum production condition where the exhaust gases at 2,522.40 ° C (2,800 ° F) are diluted with air at 25 ° C (77 ° F) to To produce a current of 532.40 ° C (1000 ° F), the resulting percentage of gas output will be greater than 7.5 times the maximum production condition with oxy fuel. Duct systems are not able to handle this much because of the increase in performance due to the limitations of the pressure drop. The furnace pressure will increase, possibly leading to a structural failure. There are several ways to treat the volume of gas increased in the pipeline: for example, reduce production, enrichment of oxygen for combustion, alternative ways to cool the gases in the pipelines (for example, with water), use additional output capabilities of gas from the pipelines, diverting the gas treatment section from the pipelines, or a combination of two or more of these methods mentioned above. A preferred method for resolving the volume increase of the gasses of the ducts, according to the present invention, is to combine water cooling, reduce production, and if necessary oxygen enrichment for combustion. Figure 9 shows the results of a thermodynamic calculation in which liquid water at 25 ° C (77 ° F) provides direct evaporative contact cooling. The percentage of normalized outflow after dilution with water was plotted against the percentage of normalized oxygen flow. The output flow is normalized with respect to 100% of the fuel with oxy, the maximum production condition where the exhaust gases at 1522. 0 ° C (2800 ° F) are diluted with air at 25 ° C (77 ° F) to produce a gas stream at 532.40 ° C (1000 ° F) ). The quantity shows that the volume of the exit gas can be reduced by 50% for the operation of maximum production with oxy fuel, when the water is replaced by air as the cooling medium in the output stream. For the condition of maximum production using air instead of oxygen for combustion and water is used to cool the exhaust gases, the percentage of outflow is 3.6 times the base condition of maximum production, the condition of maximum fuel with oxy . For 50% of the production using air instead of oxygen as oxidant, the volume of the output stream is approximately 2.5 times larger than the base condition of maximum production, the condition of maximum fuel with oxy. TABLE 1 Substitute Burner and Method Summary they are opened using predesigned burner blocks for the air fuel substitute. 3. The cross section of the cross section of the burner block is such that the burner block is such that the oxidizer oxidant speed is less than 152.4 less than 76.20 m / sec. (250 m / sec (500 ft / sec.) At feet / sec.) At the minimum minimum speed of the cross section section burner or cross section speed of the burner or burner body during the burner body during the substitute operation. substitute operation. 4. The air is used as the oxidizing oxygen concentration during the operation during the substisubstitute operation. tuta is less than 50%. 5. Cooling of the gas of the gas cooling of the pipelines with water. ducts with a combination of water and air. 6. The temperature of the device. The temperatures of the oxidation device are less than oxidation are less than 66 ° C (150 ° F). of 532.40 ° C (1000 ° F). 7. Blocks are not needed Up to twice the number of additional burners during burners used for the operation of substitute operation with fuel with They are alternatives for the proposed invention: Option 1) a continuous ignition with fuel with 100% oxy; Option 2) heat maintenance with burners heated with fuel with air; Option 3) Heat maintenance or some production with a high momentum of the oxy fuel burners using air instead of oxygen. The difference between the proposed invention and option 1, is a reduced use of oxygen and a cost of storage of liquid oxygen. The difference between the proposed invention and option 2, is a continuous production and an expense. The difference between the invention and option 3 is the technical difficulty of supplying air with high pressure. The benefit of the invention compared to option 1 is a lower capital cost (fewer LOX storage tanks). Also, depending on the period of time that the oxygen plant in the site is in suspension, the problems of logistics and availability of liquid oxygen are avoided. A benefit of the proposed invention compared to option 2, is a maximum higher temperature in the furnace with a similar temperature profile necessary for the production of glass. Still another benefit of the proposed invention compared with option 2, is the continuous production. The most effective process is where maximum production is continued using air or air enriched with oxygen. Even at the minimum level of production to maintain a strip of glass in the floating bath is extremely valuable. To restore the glass strip takes time and can delay production for one or more days. For example, for a flat glass oven that produces 600 tons per day, and with a glass valued at $ 300 per ton, a few days of production are valued at $ 180,000. An additional benefit of the invention compared with option 2 is that the substitute system is in place. Option 2 requires an outside company to come to the installation and install their equipment. Still a further benefit of the invention is that the refractory furnace does not need to be perforated, cut or otherwise altered. The present invention provides the user with the ability to use different burners for operation with fuel with air and fuel with oxy, a common mounting system for fuel burners with air and fuel with oxy, higher maximum furnace temperatures compared to fuel heat burners with air. The process of the present invention is capable of generating a similar temperature distribution in a furnace required for glass processing, allows higher firing rates, use of separate but closely spaced gates for the introduction of air and fuel for operation of fuel with air. For the operation of fuel with oxy, a larger opening is used as a pre-combustion chamber with a fuel flow with oxy and a smaller opening for oxygen titration. For air fuel operation, larger openings are used for air or oxygen enriched air to flow and a smaller gate fundamentally for the fuel. It is within the scope of the present invention to have a separate burner block or a pre-combustion chamber positioned on the wall of the furnace to introduce air or air enriched with oxygen and fuel inside the furnace. In this mode the oxy fuel burner will be turned off and the separate burner block will be used to effect combustion in accordance with the teachings of the invention. Also within the scope of the present invention to introduce oxygen enriched air or air into the furnace through separate burners or pipes that are independent of oxy fuel burners, while air or air enriched with oxygen and fuel are introduced in accordance with the teachings of the invention. Having thus described our invention, what is desired to be ensured by the United States Patent of Invention is set forth in the appended claims.

Claims (20)

1. CLAIMS 1. A process for maintaining the heating of an oven at an elevated temperature using the combustion of fuel with oxy, where the fuel flame with oxy is introduced into said furnace and an oxidant is introduced under said flame, when the supply of oxygen to said flame and said oxidant is eliminated or terminated comprising the steps of: replacing said fuel flame with oxy with a flame of air or oxygen enriched air and introducing said fuel with oxygen enriched air or air within said oxygen. oven; and replacing said oxidant with said fuel and introducing said fuel into said furnace to provide combustion and maintaining said temperature in the furnace. A method according to claim 1, wherein said furnace is a glass melting furnace with a temperature distribution maintained in said furnace when using the combustion of air, except in those burners adjacent to the regions of extreme heating in said furnace, where a combustion of air enriched with oxygen is used. 3. A method according to claim 1, which includes replacing said fuel flame with oxy with air introduced at a flow percentage of 12.6 times larger than the percentage of flow of the fuel flame with oxy or oxygen, when only the combustion of fuel with oxy is used. A method according to claim 1, wherein the rate of said combustion of air or air enriched with oxygen at a discharge end of said burner is less than about 76.2 m / sec. (250 feet / sec.). A method according to claim 1, which includes introducing said combustion of air or air enriched with oxygen and fuel through a burner block. 6. A method according to claim 1, including the steps of introducing oxygen with said fuel to increase the transfer of emission and diffusion of heat to a load that is heated in said furnace. A method according to claim 1, which includes the step of cooling the exhaust gases leaving said furnace with liquid water, to decrease the volume of said exhaust gases, compared with the cooling of said exhaust gases with air. 8. In a combustion system of the type having a fuel burner with oxy adapted to produce a flame with a pre-combustion chamber mounted on said burner, said pre-combustion chamber having a first passage with a first end in an airtight relation of fluid with one end of the flame of said burner and a second end adapted to direct the flame produced by said burner for heating industrial environments in a flat configuration similar to a fan and a second separate passage in said burner block arranged due to said first passage and coextensive therewith, said second passage terminating at a nozzle end at said second end of said combustion chamber for directing the oxidation fluid beneath the flame and generally parallel therewith, the improvement comprises : a first element for introducing a flame of air or air enriched with oxygen through said burner inside the pre-combustion chamber instead of said flame; and a second element for introducing said second separate passage in said pre-combustion chamber in place of said oxidation fluid, whereby said combustion system can continue the heating of an industrial environment in the event that the supply is interrupted or reduced of oxygen. 9. A system according to claim 8, wherein said pre-combustion chamber has a length between 10.16 to 45.72 cm (4 and 18 inches). A system according to claim 8, wherein said first passage and said second passage have a ratio of the width in relation to the height of 5 and 30 in said second end of said pre-combustion chamber. 11. A system according to claim 10, wherein the walls defining the width of said first passage and said second passage of said pre-combustion chamber are arranged at an angle between -15o0 to +30 ° on either side of the central vertical plane through said pre-chamber. -combustion. 12. A system according to claim 11 wherein said angle is between 0o to + 15 ° on either side of said vertical plane. A system according to claim 8, wherein there are included elements for introducing oxygen into said fuel in said pre-combustion chamber. A system according to claim 8, used to heat an oven with elements for cooling with water the exhaust gases emerging from said oven when said burner is in use. 15. A process for maintaining heating of an oven at an elevated temperature using an oxy fuel combustion, wherein a fuel flame with oxy is introduced into said furnace, when the air supply for said flame is removed or finished comprising the steps of: introducing a stream of air or air enriched with oxygen into said furnace; and introducing a separate stream of said fuel into said furnace to provide combustion and maintain the temperature in said furnace. 16. A method according to claim 15, wherein said furnace is a glass melting furnace with a temperature distribution maintained in said furnace when using a combustion of air, except in those burners adjacent to an extreme heating region. in said furnace where a combustion of air enriched with oxygen is used. 17. A method according to claim 15, which includes replacing said fuel flame with oxy with air introduced at a flow percentage of approximately 12.6 times greater than the percentage fuel flow with oxy or oxygen when used just a combustion of fuel with oxy. 18. A method according to claim 15, wherein the velocity of said air or oxygen enriched air flame at a discharge end of a burner used to introduce said air or oxygen enriched air flame into said furnace is smaller than approximately 76.2 m / sec. (250 feet / sec.). A method according to claim 15, which includes the steps of introducing oxygen with said fuel to increase the transfer of the emission and diffusion of heat to a load that is heated in said furnace. A method according to claim 15, which includes the step of cooling the exhaust gases leaving said furnace with liquid water to decrease the volume of said exhaust gases, compared with the cooling of said exhaust gases with air .