MXPA00002273A - Oxygen-fuel boost reformer process and apparatus - Google Patents

Abstract

A process and apparatus for the production of reformed gases. Natural gas and oxygen are combusted in a first stage (196) to produce carbon dioxide and water. The products of combustion are conveyed to a second stage (202). Reforming gas and oxygen are injected into the second stage (202) and mixed with the products of combustion to react with the carbon dioxide and water to produce carbon monoxide and hydrogen. The process and apparatus are particularly adapted for use in supplementing the reform gases produced in a Direct Reduced Iron plant wherein iron ore is reduced to iron inside a shaft furnace. The process and apparatus may also be used to provide heated enrichment natural gas for use as a source of carbon in the shaft furnace to provide for carburization of the iron. Additonally, the process and apparatus may be used as a process control device for controlling the temperature of the reformed gases flowing to the shaft furnace.

Description

REFORM PROCESS FOR OXYGEN REINFORCEMENT - FUEL AND APPLIANCE 1. FIELD OF THE INVENTION This invention relates generally to a process and apparatus for producing reforming gases. More particularly, this invention relates to a process and apparatus for producing reforming gases to enhance the reformer gas capacity of existing reformers. 2. Background Processes to make reforming gases are widely used throughout the world and have particular application in relation to Iron Direct Reduction (HRD) plants. The HRD plants use reforming gases in large quantities to reduce the iron ore (FeO) to iron (Fe) within an axis furnace. The iron of the shaft furnace is then processed to various grades of steel to manufacture final products such as wires, rods, spokes, and the like. The reformer gases used in the shaft furnace are mainly a mixture of hydrogen (H2) and carbon monoxide (CO) in the general ratio of 1.5: 1, respectively. These reforming gases (H2 and CO) provide the following metallization reactions in the shaft furnace: FeO + H2? Fe + H2O FeO + CO? Fe + CO2 The stoichiometric calculations of the above reactions indicate that 400 cubic meters of CO or H2 they react with iron ore (FeO) to form 400 cubic meters of CO2 or H2O for each metric ton of FeO reduced iron. Chemical calculations require that the ratio of reducers (CO + H2) to oxidants (CO2 + H2O) be greater than about 2: 1 before any reduction occurs. Therefore, the reformer gas entering the shaft furnace must have a sufficient amount of reducers to allow the conversion of 400 cubic meters of reductants into oxidants per ton of iron, and still have a ratio of 2: 1 of reductores- a oxidizers after all the FeO is reduced to Fe. The metallization process is carried out in the shaft furnace in which the iron oxide is fed from the top into a feed hopper and distributed in the furnace by several distribution tips. The shaft furnace has three zones in which the process is carried out; a reduction zone, a transition zone and a cooling zone. A pipe (section of larger diameter) is provided in the furnace which has ports that open in the lower part of the reduction zone through which the gas from the pipe is injected into the furnace to pass upwards to through a bed of an iron ore in the reduction zone. The gas in the pipe is mainly reforming gases (H2 and CO) as well as CO2, H2O and natural enrichment gas. A usual pipe gas composition is as follows: CO2 = 02.5% CO = 38.0% H2 = 56.0% CH4 = 02.0% N2 = 01.5% Nitrogen is present due to the air entering the process at several points, and also due to the fact that the natural gas used in the process it can contain up to about 2% nitrogen. The gas temperature of the pipe is around 898.8 ° C. This temperature is achieved after the addition of natural enrichment gas to reformer reformer gas. The natural enrichment gas is added to provide a source of carbon in the reduction zone. This allows the addition of carbon to the iron in the reduction zone by the following carburization reaction: 3Fe + CH4? Fe3C + 2H2 This reaction is endothermic and reduces the temperature of the iron oxide bed. The amount of iron oxide feed, pipe gas temperature, H2 / CO ratio and the amount of CO2 reformed gas are highly controlled by the operation control cycle of the plant. The most effective carbon control techniques currently practiced involve the controlled addition of quantities of natural gas to the gas in the pipe. Many plants operate between about 2.5% to around 3.5% CH4 in the pipeline gas reduction zone and around 20.0% to around 50.0% CH4 in the control zone. Nevertheless, the addition of CH as the enriched gas for the reformed gases entering the pipe tend to reduce the gas temperature of the pipe making the control of the gas temperature of the pipe more difficult. The process of manufacturing the traditional reformed gas for HRD plants is carried out in a reformer wherein a hydrocarbon feed gas, such as natural gas, methane, propane and the like, is reacted with H2O and CO2 (from about from 1037.7 ° C to around 1093.3 ° C) in the presence of a catalyst to produce the CO and H2 reducers. The centerpiece of the equipment is an oven consisting of a refractory duct covering containing reformer tubes filled with catalyst. The fuel is burned on the deck at a slightly atmospheric pressure, while a mixture of natural gas, H2O and CO2 is passed through the tubes containing the catalyst pellets made of such materials as nickel or alumina nickel. Reformer reactions are characterized by being endothermic (requiring the entry of heat) and requiring a catalyst to accelerate the reforming reactions. As a result, multiple burners are lit on the cover to provide the necessary heat input. The feed gas (natural gas, methane or propane) is fed from the reformer tubes from an external source while the CO2 is supplied to the reformer tubes in the form of kiln gas from the shaft furnace. The necessary water (H2O) is added before the gas mixture enters the reforming tubes. The feed gas and the H2O and CO2 are mixed and heated in the reformer tubes filled with catalyst to cause the following two reforming reactions to occur in the reforming tubes: CH4 + CO2? 2CO + 2H2, and CH4 + H2O? CO + 3H2. A usual reformed gas leaving the reformer gas tubes may have a temperature of about 926.6 ° C and the following composition (on a dry basis): H = 58.0%; CO = 38.0%; CO2 = 2.85%: CH4 = 0.5%; and N2 = 1.0%. The quality of the reformed gas is defined by the ratio of reducers (H2 + CO) to oxidants (CO2 + H2O), the bigger the better. A usual value for the ratio of reductants to oxidants is around 12 with an H2 / CO ratio of 1.5 to 1. Several factors affect the quality and flow regime of reformed gas. Such factors include the exit of the reformer, the temperature of the reformer tube and the size of the reformer burner. If the reformer outlet (reformed gas flow rate) is increased beyond the design capacity of the reformer, the heat load supplied by the reformer burners also increases. As the heat load increases, the catalyst in the center of the reformer tubes cools due to the increased heat removal rate through the tubes. The colder catalyst tends to increase the potential for undesirable carbon deposits in the tube, thus reducing the overall reforming performance. The quality (composition) and flow regime of the reformed gas would be seriously affected due to the operation above the designated capacity. An increase in the temperature of the reformer will also increase the temperature of the reformer tube. This can produce thermal stresses and possible damage and distortion to the material of the reformer tube (usually silicon carbide). A damaged reformer tube could cause a complete plant shutdown and loss of production. The reformer burners are coupled for a certain ignition capacity and flame characteristics. The ignition in addition to the design capacity of the reformer would provide an unacceptable temperature profile along the length of the reformer tube and a potential overheating of the furnace shell of the refractory reformer. A limit of 1204.4 ° C is usual for the reformer. An unacceptable temperature profile along the length of the reformer tube could affect the activity of the catalyst and the reforming action within the tube, and result in a deterioration in the quality of the reformed gas. This could result in low metallization rates by the shaft furnace and / or reduced iron production of poor quality. Due to the above, the most direct reduction plants are not able to increase their capacity of reformed gases since the reformer exceeding the capacity of the reformer. On the other hand, the shaft furnace is generally capable of increasing through 20% to 30% of the reduced iron if the additional reformed gases could be supplied by the metallization reactions inside the furnace. If a plant wants increased output from its shaft furnace, the options left by the plant are to install a new bank of reformer tubes and a reformer furnace or to acquire the reduced iron from another supply. None of these options is cost effective. The cost of a new reformer tube and reformer furnace requires a capital expenditure of millions of dollars and such new reformer tubes may not be necessary every time due to market demand and total flexibility in the production cycle. The acquisition of reduced iron from another supplier is subject to the changing market price and availability and does not present a satisfactory solution to increase the output of reduced iron. In view of the above, it is desired to provide a relatively inexpensive option that could increase the availability of demand reforming gases to allow an increase in the production of reduced iron when market conditions demand it, and which can go back to the original capacity of the existing reformer when market conditions dictate a reduced output. COMPENDIUM OF THE INVENTION In view of the foregoing, it is an objective of the present invention provide a simple reformer gas that produces apparatus and processes for producing reforming gases. Another object of the present invention is to provide an apparatus and process for producing the reformer gas which can be economically used to supplement the output of existing gas reformers. A further objective of the present invention is to provide an apparatus and process producing reforming gases for use in direct reduction iron plants to provide supplemental reforming gases in order to supplement the output of existing reformers. Still another object of the present invention is to provide an apparatus and process producing reforming gases that can be used, together with the existing gas reformers, to adjust the temperature of the global reformed gas. Still another object of the present invention is to provide an apparatus and process for producing reforming gases for use in direct reduction iron plants to provide supplemental reforming gases in order to supplement the output of existing reformers, and which can be used to control the amount of natural enrichment gas that is supplied to the iron reduction furnace. These and other objects and advantages of the present invention can be achieved in accordance with one aspect of the present invention through the provision of a method for generating reforming gases in order to provide additional capacity of the reforming gas. The method comprises burning a mixture of a first supply of a gaseous hydrocarbon and oxygen in a first phase to provide flame gases; passing said flame gases in a second phase; injecting a second supply of a gaseous hydrocarbon and oxygen in said second phase; and causing said flame gases to react with said second supply of said gaseous hydrocarbon in the second phase to produce reformed hydrogen and carbon monoxide. According to another aspect of the present invention, a gas reformer is provided to generate reforming gases comprising a burner for burning a mixture of a first supply of a gaseous hydrocarbon and oxygen in a first phase to produce combustion products; an elongated mixing tube that provides a second phase in which said combustion products are transported; and an injector for injecting a mixture of a second supply of a gaseous hydrocarbon and oxygen in said second phase for reaction with the combustion products of said first phase to produce reformed hydrogen and carbon monoxide.

According to another aspect of the present invention, a method is provided for supplying the amount of reformer gas used in direct reduction iron plants where the primary reformed gas is supplied to a furnace from a primary reformer and passes through the ore. of iron to produce iron. The method comprises the combustion of a mixture of a first supply of a gaseous hydrocarbon and oxygen to produce carbon dioxide and water; passing said carbon dioxide and water in a second phase; inject a second supply of a gaseous hydrocarbon and oxygen in a second phase; causing said carbon dioxide and water to react with said second supply of said gaseous hydrocarbon in said second phase to produce secondary reformed hydrogen and carbon monoxide; and injecting said secondary reformed hydrogen and carbon monoxide into the path of the primary reformed gas to the furnace. According to yet another aspect of the present invention, a gas reformer is provided to generate reforming gas supply in a direct reduction iron plant wherein the primary reformed gas is supplied through a path from a primary reformer to a furnace and passes through the iron ore to produce iron. The reformer comprises a burner for the combustion of a mixture of a first supply of a gaseous hydrocarbon and oxygen in a first phase to form combustion products; an elongated mixing tube that provides a second phase in which said combustion products are transported, said mixing tube opening in the path of the reforming gases to said furnace; and an injector for injecting a mixture of a second supply of a gaseous hydrocarbon and oxygen in said second phase for reaction with the combustion products of said first phase in order to produce reformed hydrogen and carbon monoxide which leaves said tube of mixing and enters the trajectory of said reforming gases. The present invention can be better understood by reference to the following detailed description and the accompanying drawings in which: BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram of a direct reduction iron plant including an axis furnace and reformers for the direct reduction of iron using reformed gases; Figure 2 is a schematic diagram showing the present invention used in relation to the shaft furnace and the reformer of Figure 1; Figure 3 is a schematic diagram of the oxygen fuel booster reformer (RROC) and process according to the present invention; Figure 4 is a cross-sectional view of an embodiment of an oxygen fuel booster reformer embodying the present invention, showing the reformer installed in an upper reformed gas collector; Figure 5 is a cross-sectional view of a second embodiment of an oxygen fuel booster reformer according to the present invention, showing the reformer mounted in a top reformed gas collector; and Figure 6 is a cross-sectional view of a third embodiment of an oxygen fuel booster reformer in accordance with the present invention, showing the reformer mounted in a top reformed gas collector. DETAILED DESCRIPTION Referring to the drawings, and particularly to Figures 1 and 2, there is shown a schematic diagram of a process and apparatus for the direct reduction of metal oxides such as iron ore to which the present invention is particularly applicable. The apparatus and process shown are typical of those commercially used in many direct reduction iron (HRD) plants. The apparatus may include an axis furnace 2 in which the iron ore (FeO) is reduced to iron (Fe) using reformed gases. The reformed gases are produced in a reformer 4 and fed to the pipe 6 of the shaft furnace 2 through an upper collector 8. The shaft furnace 2 can include a feed hopper 10 in its upper part of which the ore of iron 12 is fed into a proportional hopper 14 of which is distributed in a furnace 2 by distribution ends 16. The furnace of axes 2 includes three zones; a reduction area "A" generally in cylindrical form, a transition zone "B" and a cooling zone "C". The pipe 6 of the shaft furnace 2 is an elongated section at about half the length of the furnace 2 and includes a plurality of ports 18 spaced around its inner circumference and opening in the center of the furnace 2 through which the upper gas comes out of the oven 2. The appropriate cooling gas inlets 22 are provided for the cooling gas inlet in the cooling zone "C". The gas outlets of the oven 24 are provided adjacent to the top of the cooling zone "C" so that the gas leaves the oven, mainly carbon dioxide (CO2). A gas seal tip 26 is provided in the bottom of the furnace 2, under which a vibrating screen 28 is provided to provide for the removal of the cooled direct reduction iron. The reformer 4 is generally an oven consisting of a refractory duct cover 30 containing rows of reformer tubes filled with catalyst 32. The suitable burners 34, which extend upwards in the cover 30 lateral to the tubes 32, are ignited in cover 30 to provide the necessary heat input. A feed gas such as natural gas, methane, or other suitable gaseous hydrocarbons is fed to the reformer tubes 32 through a feed gas conduit 36 from an external source such as the main supply plant. Generally, the feed gas is natural gas which can be from 96 to about 98% methane and above about 2.0% nitrogen: The feed gas flows from its source through line 36 to a preheater 38 The branched conduits 40 of the feed gas conduit 36 are connected to the burners 34 to provide a flow of natural gas to the reformer burners 34. A conduit 42 of the gas outlets of the furnace 24 having a pump 44 in the same, provides by furnace gas flow from the furnace 2 through a scrubber 46 to the feed gas conduit before it enters the preheater 38. The feed gas conduit 36 leaves the preheater 38 and is connected to the pipes reformers 32 for supplying a feed gas flow to the tubes 32. A water conduit 48 is connected to the feed gas conduit 36 after the preheater 38 and downstream of the pipes 32 to add H2O to the gas which enters the tubes 32. An air blower 50 connected to a conduit 52 passes through a preheater 38 to the burners 34 to provide preheated air to the burners. The reformed gases exiting the reformer tubes 32 pass through the suitable conduits 54 in the upper collector 8 where the reformed gases from the different rows of the tubes 32 are collected and then passed through a flow conduit 56 to the pipe 6 of the shaft furnace 2. A conduit 58 is connected to the conduit 56 to the pipe 6 to add a natural enrichment gas to the gas of the upper collector to form the gas of the pipe entering the pipe 6. The gas of The pipe passes through the ports in the pipe 6 and passes through the iron oxide bed in the reduction zone of the furnace as indicated by the arrows. In reformer 4, the mixture of natural gas (or other suitable hydrocarbon such as methane and propane) and H 2 O and CO 2 is passed through tubes 32 containing a suitable catalyst such as nickel or an alumina-nickel composition and reacts to produce the CO and H2 reducers according to the following reactions: CH4 + CO2? 2CO + 2H2, and CH4 + H2O? CO + 3H2 The reformed gas leaving the tubes 52 can usually comprise 58% H2, 38% CO, 0.5% CH4, 2.5% CO2, and 1.0% N2 and has a temperature of about 898.8 ° C . This reformed gas is passed through conduit 56, where the natural enrichment gas is added to form the gas from the pipe., to the pipe 6 of the furnace of axes 2 in the reduction zone "A" of the furnace of axes 2 where it is passed upwards through the bed of iron oxide that provides the following metallization reactions in the reduction zone: FeO + H2? Fe + H2O FeO + CO? Fe + CO2 After it is reduced, the resulting iron (Fe) passes through the transition zone "B" to the cooling zone "C" of the furnace where the iron is cooled by the cooling gas. The cooling gas is usually natural gas at room temperature. After cooling, the resulting iron is discharged through the gas sealing end 26 onto the vibration screen 28 and transported out of the furnace. In accordance with the present invention, an oxygen-fuel booster reformer (RROC) 60 is provided to produce secondary reformer gas to reinforce the capacity of the normal or primary reformer. (For purposes of description, the reformed gas produced by the existing reformer in the plant 4 is referred to herein as the primary reforming gas, while the reformed gas produced by the process and apparatus of the present invention is referred to as the secondary reformed gas). The oxygen-fuel booster reformer 60 can also be used to supply the natural enrichment gas and provide temperature control supply of the total reformed gas to the shaft 2 furnace as will be explained later. As shown in Figures 2 and 3, the oxygen-fuel reinforcing reformer 60 is mounted downstream of the primary reformer 4 in the upper reformed gas collector 8. However, the oxygen-fuel reinforcement reformer 60 of the present invention, can be assembled in other places while said places are provided for a good mixing of the ^ *** m *** m secondary reformed gases injected from the oxygen-fuel booster reformer 60 with the primary reformed gas. Such other locations include locating the oxygen-fuel booster reformer 30 in line 6 of the shaft furnace to inject the secondarily reformed gases directly into line 6, or locate the oxygen-fuel booster reformer 60 in the line of reformed gas 56 which transports the reformed gases from the upper collector 8 to the pipe 6 of the kiln 2. The oxygen reinforcing fuel reformer 60 generally comprises a burner 62 in which the oxygen burner and natural gas burner are mixed and they burn. An inlet port 64 in the reformer 60 provides an inlet for the natural gas to enter an elongated burner tube 66. An inlet port 68 is provided for oxygen to enter a chamber 70 around the burner of the tube 66. oxygen leaves the chamber 70 and mixes with the natural gas and the mixture is burned, with the combustion products flowing in a mixing tube 72. The reformer 60 also includes an inlet port 74 (or ports) for the inlet of the reformer natural gas and oxygen in the elongated mixing tube 72, preferably through a stirrer 75, at a point downstream of the combustion point of the burner gases. The reformer and oxygen natural gas are mixed with the combustion products of the natural gas and oxygen from the burner in the elongated mixing tube 72 to produce the reforming reactions in the mixing tube 72. The oxygen-fuel booster reformer 60 of the present invention provides a two-phase process for providing the reforming gases. A first phase 76 (Phase I) is provided in which almost stoichiometric proportions of natural gas from the burner and oxygen from the burner are mixed and burned, creating an oxygen-fuel flame. The combustion of natural gas and oxygen produces the following stoichiometric reaction of Phase I: CH4 + 2O2? CO2 + 2H2O The combustion flame gases are transported in a second Mixing Phase 78, (Phase II), within the elongated mixing tube 72, in which a predetermined amount of reformer and oxygen natural gas is injected, preferably at an oscillatory configuration to provide the following Phase II reactions: CH4 + CO2? 2CO + 2H2, and CH4 + H2O? CO + 3H2. The resulting gases of the oxygen-fuel booster reformer are CO, H2, H2O, CH4 and CO2. CH4 in the resulting gases is presented as natural enrichment gas that arises due to additional amounts of reformer natural gas that is supplied to Phase II over what is necessary for, and consumed in, the reaction that occurs in Phase II.

Although the oxygen-fuel booster reformer and process of the present invention is described as being supplied with natural gas and oxygen for both Phases I and II, it is contemplated that various gaseous hydrocarbons such as natural gas, propane, methane, and the like may be used, and the oxygen source may be commercial grade oxygen, air, or mixtures thereof. Figures 4-6 show various embodiments of an oxygen-fuel booster reformer that can be used to carry out the oxygen-fuel booster reformer process. As shown in Figure 4, an oxygen-fuel reinforcing reformer 80 is mounted on the end wall 82 of the primary reformed gas top collector 8, and includes a refractory duct mixing tube 84 attached to, and extending through, the wall of the upper gas collector reformed 82 inside the upper collector 8. An external tube 86 is mounted on the end of the mixing tube and surrounds an elongated intermediate tube. 88 which is radially separated from and coaxial with them. An inner tube 90 is provided inside the intermediate tube 88 and separates radially inwardly therefrom and is coaxial with them. The outer tube 86 forms an annular chamber 92 around the intermediate tube 88 which is closed at its outer end by a suitable lock 94. The intermediate tube 88 extends axially towards the end of the end of the outer tube 90 which is closed in its external end by a suitable lock 98.

The outer tube 86 is provided with a first port 100 that communicates with the chamber 92 for connection to a reforming oxygen source. A second port 102 in the outer tube, which communicates with the chamber 92, provides a means for connecting a reformer natural gas source to the chamber 92. Alternatively, natural gas and oxygen can be mixed and entered into the chamber through a single port. A port 104 is provided in the intermediate tube 88, axially at the end of the outer tube 86, which communicates with the chamber 96 to connect a source of oxygen from the burner to the chamber 96. The inner tube 90 has a port 106 at its end external, which communicates with the interior of the same, to join a source of natural gas. A nozzle 108 of high temperature steel alloy such as SS-310, Inconel, Hastealloy or the like, is provided at the rear end of the inner tube 90 as shown. A Venturi 110, made of refractory material, is mounted in the intermediate tube 88, axially forward of the initial internal end of the inner tube 90, and is placed in the passageway 112 of the Venturi 110 separating forward and inward of the initial end of the tube. the nozzle 108 of the inner tube 90 and the diverging section 114 of the Venturi 110 is opened in the mixing tube 84. A stirrer 116 is mounted between the outer tube 86 and the intermediate tube 88 as shown, with the Venturi 110 extending axially forward within the mixing tube 84 a slight distance after the agitator 116.

The agitator 116 may have the shape of angled fins or vanes positioned around the circumference of the initial end of the chamber 92 between the outer tube 86 and the intermediate tube 88. The agitator 116 is preferably formed of steel alloys and has the shape of helical guide vanes. The blades can have an angle of agitation with respect to the axis of flow of between 30 and 60 degrees. Generally, four to six fins are sufficient, depending on the size of the oxygen-fuel reinforcing reformer 80. With the embodiment of Figure 4, the natural gas is fed through port 106 to the inner tube 90 and flows through it. the nozzle 108 in the passage 112 of the Venturi 110. Oxygen is fed through the port 104 in the chamber 96 between the inner tube 90 and the intermediate tube 88 and then flows in the passage 112 of the Venturi 110. The exit area of the nozzle 108 and the passage area at the end of the chamber 96 are chosen in such a way that there is a relatively high injection speed between about 220 to about 240 meters per second of the burner gas and burner oxygen in the passage 112 of Venturi 110. Burner oxygen and natural gas from the burner collide with each other in passage 112 of Venturi 100 resulting in good mixing conditions. The diverging section 114 of Venturi 110 preferably has a length of about 2 to about 6 times the minimum diameter of passage 112, and provides for the mixing of oxygen and natural gas and oxygen-fuel flame formation in the Phase I area 118. The flame is initially formed by the combustion of the oxygen-natural gas mixture at the Phase 1 118 area in the diverging section 114 of the Venturi 110 by the heating of, and physical mixing with, the surrounding primary reformed gas in the upper collector surrounding the exterior of the mixing tube 84. These primary reformed gases usually have a temperature in the range of about 871.1 ° C to about 926.6 ° C. A very inconspicuous flame of radiation is preferred for this Phase I operation where natural gas and oxygen react stoichiometrically to form water and carbon dioxide. In the modality of Figure 4, Venturi 110 is preferably formed of a refractory material due to the high temperature fuel oxygen flame. A Venturi mixer cooled with water should be used for higher ignition capacities (greater than 2 MM Btu / Hr). In such higher ignition capacities, the natural gas nozzle 108 can be provided with multiple axial recesses to improve mixing with the surrounding oxygen stream. Natural gas, or other gaseous hydrocarbons, and oxygen, are fed through their respective ports 102 and 100 to chamber 92 in the correct proportion. The oxygen and natural gas leave the chamber 92 through the gas agitator 116 in the mixing tube 84 in the Phase II area 120 forward of the initial end of the Venturi 110. The agitator 116 provides two functions. First, it must provide sufficient agitation movement to the natural gas-oxygen mixture to create rapid mixing in the Phase I combustion products, which leave Venturi 110 in the Phase II 120 area. Second, it could scrape the internal surface 122 of the mixing tube 84 to provide cooling which is necessary due to the thermal radiation of the combustion products of Phase I of high temperature. Mixing and combustion in the Phase I 118 area occur substantially in the diverging section 114 of the Venturi 110. Mixing and reaction in the Phase II area 120 begins to occur within the mixing tube 84 immediately downstream of the end. Initial Venturi 110. As previously stated, Phase I combustion gases react with the natural gas-oxygen mixture in Phase II to form carbon monoxide and hydrogen from secondary reformed gases. These gases pass from the mixing tube 84 to the upper reformed gas collector 8 and supply primary reformed gases that pass to the shaft furnace 2. Figure 5 shows a second embodiment of an oxygen-fuel reinforcing reformer 150 which modalizes the present invention. As in the above embodiment, the reformer 150 is mounted on the wall 82 of the primary reformed gas top collector 8. The reformer 150 includes a refractory duct mixing tube 152 attached thereto and extending through the wall of the collector. refurbished gas upper 82 in the upper collector 8. An outer tube 154 is mounted at the rear end of the mixing tube 152 and surrounds an elongated cooling jacket 156 which is radially withdrawn inward from the mixing tube 152 and is coaxial with the same. An inner tube 158 is provided within the cooling liner 156 and is radially disengaged therefrom and coaxial therewith. The outer tube 154 forms an annular chamber 160 around the cooling liner 156 which is closed at its rear end by a suitable lock 162. The cooling liner 156 extends axially towards the rear end of the outer tube 154 and forms a chamber 164 with inner tube 158 which is closed at its trailing end by means of a suitable lock 166. Cooling liner 156 can be formed by means of an external cooling liner tube 160 coaxial with outer tube 154 and is separated radially into the outer tube 154 to form the annular chamber 160 therewith. The external cooling jacket tube 168 extends into the mixing tube 152 beyond the initial end of the outer tube 154 as shown. An inner cooling jacket tube 170, smaller in diameter than the external cooling jacket tube 168, is provided inside the external cooling jacket tube 168 and is coaxial with it to provide an annular space therebetween. An intermediate cooling jacket tube 172 is interposed between the inner and outer cooling jacket tubes 170 and 168 to provide longitudinally extending internal and external annular passages 174 and 176, respectively. The initial ends of the inner and outer cooling liner tubes 170 and 168 are interconnected by means of a lock member 178. The intermediate cooling liner tube 172 is axially separated towards the rear of the lock member 178 in such a way that there is communication between the internal and external annular passages 174 and 176 at the initial end of the cooling liner 156. The outer passage 176 closes at its rear end of the external cooling liner tube 168 to the wall of the water liner tube intermediate 172. The trailing end of internal passage 174 is closed by a lock member 182 extending the trailing end of the intermediate cooling liner tube 172 and the internal cooling liner tube 170. A cooling fluid inlet port. 184, which communicates with the internal passage 174, is provided in the wall of the intermediate cooling liner tube 172 adjacent to the rear end of the same and is placed posteriorly from the lock member 180 of the external passage 176. A cooling fluid outlet port 186 is provided in the tube wall of the external cooling jacket 168, adjacent to the outer end thereof and which it communicates with the external passage 176. With this arrangement, the cooling fluid, such as water, can enter the internal passage 174 through the port 184 adjacent the rear end of the passage 174, flowing forward along the internal passage 174, around the initial end of the intermediate cooling liner tube 172 and towards the rear through the outer passage 176 to the exit port 186 where it leaves the cooling liner 156. The outer tube 154 is provided with a first port 188 which communicates with the chamber 160 for connection to a reforming oxygen source. A second port 190 in the outer tube 154 also communicates with the chamber 160, provides a means for connecting a reformer natural gas source to the chamber 160. Alternatively, the natural gas and oxygen can be mixed and entered into the chamber through a single port. A port 192 is provided in the wall of the inner water liner tube 170, axially towards the rear end of the intermediate water liner tube 172, which communicates with the chamber 164, to connect an oxygen source of the burner with the chamber 164. The inner tube 158 has a port 193 at its outer end, which communicates with the interior thereof, to join a source of natural gas. The initial end of the inner tube 158 ends at a point spaced toward the rear of the initial end of the inner cooling liner tube 170 of the cooling liner 156 as shown. A nozzle 194 is provided at the initial internal end of the inner tube 158 which opens into the Phase I mixing area 196 which is surrounded by the water liner 156. A stirrer 198, similar to the agitator described in connection with the The embodiment shown in Figure 4 is mounted between the inner tube 158 and the inner cooling liner tube 170 at the initial internal end of the chamber 164 as shown. An agitator 200 is also provided at the initial end of the chamber 160 which extends around the external cooling jacket tube 168. With the arrangement of the reformer 150 as shown in Figure 5, the oxygen burner flows through the port 192. in the chamber 160, and leaves the chamber 160 through the agitator 198 in the Phase I area 196 with a stirring motion. The natural gas flows in the inner tube 158 through the port 193 and passes through the nozzle 194 in the mixing area of Phase I 196 and mixes with the stirring oxygen. The natural gas injection regime can be between about 220 to about 240 meters per second. The heat of the primary reduced gases in the upper collector 8 burns the mixture of combustible oxygen in the Phase I area 196 at an immediately initial point of the nozzle 194 creating a high temperature oxygen-fuel flame within the cooling shell 156. Natural gas and oxygen react stoichiometrically to form water and dioxide. carbon in Phase I. A reformer natural gas passes through port 190 in chamber 160 and mixes with the reformer oxygen that enters chamber 160 through port 188. As in the previous mode, the reformer and oxygen natural gas can be mixed before entering the chamber. The mixture of reformer natural gas and oxygen passes through the external agitator 200 in the mixing tube 156 at a point immediately downstream of the end of the water liner 156 in the Phase II 202 mixing area. At this point mixing in Phase II and the reaction, they begin to occur within the mixing tube 152. As mentioned above, the combustion gases of Phase I react with the mixture of natural gas-oxygen in Phase II to form secondary reformed gases , carbon dioxide and hydrogen. These gases are passed to the mixing tube 152 in the upper collector of reformed gas 8 and supply of primary reformed gases that pass to the shaft furnace. The water cooled combustion chamber (Phase I) provides the highest ignition capacity of the Phase I mixer (the natural gas from the burner and the oxygen from the burner). It also provides flame stability to operate the Phase I mixer at a relatively higher flame gas temperature. A third embodiment of an oxygen-fuel reinforcing reformer 250 that modalizes the principles of the present invention is shown in Figure 6. As in the case of previous embodiments, the reformer 250 is shown mounted on the end wall 82 of the collector top of primary reformed gas 8 of an existing HRD plant. In this mode, the reforming natural gas and oxygen are preheated before entering Phase II. A mixing tube 252 is bonded thereto and extends through the wall of the upper reformed gas collector 82 in the upper collector 6. The mixing tube 252 is constructed to constitute a preheater 254 for the reforming gases. The mixing tube 252 includes an external preheater tube 256 which extends through the wall 82 of the upper collector 8. The external preheater tube 256 surrounds an internal preheater tube 258 which has a smaller diameter than the external preheater tube 256. and it is coaxial between it. An intermediate preheater tube 260 is interposed between the internal and external preheater tubes 258 and 256 to provide longitudinally extending internal and external annular passages 262 and 264 respectively. The initial ends of the internal and external preheater tubes 258 and 256 are interconnected by a lock member 266. The intermediate preheater tube 260 has its internal end separated rearwardly of the lock member 266 so that there is communication between the internal and internal passages. external 262 and 264 at the initial end of the preheater 254. The tubes 256, 258 and 260 forming the preheater 254 are preferably constructed of a high temperature steel alloy such as SS-310, Inconel, Hastealloy and the like. A Phase I tube 268 of a smaller diameter than the internal preheater tube 258 extends into the inner preheater tube 258 coaxially therewith which provides an annular outlet passage 270 through the preheater 254 between its outer wall and the internal wall of the internal preheater tube 258. A lock member 272 extends from the rear end of the external preheater tube 256 to the external wall of the tube 268 of Phase I, with the rear end of the intermediate preheater tube 260 connecting to it in such a way that the rear end of the outer passage 264 is closed. The rear end of the tube of the internal preheater 258 is separated from the lock member 272 in such a way that the internal passage 262 and the exit passage 270 are interconnected. agitator 273 may be provided at the initial end of the exit passage 270. A first port 274 is provided in the external preheat tube 256, communicating with the p gripping the external preheater 264, to connect the source of the reformer oxygen to the external passage 264. A second port 276 in the external preheater tube 256, provides a means for connecting a reformer natural gas source to the external passage 264. Alternatively, natural gas and oxygen can be mixed together and enter the external passage 264 through a single port. A burner tube 278 extends coaxially into the tube 268 in Phase I and has a smaller diameter than the Phase I tube 268 to provide a chamber 280 between the Phase I tube 268 and the internal burner tube 278. A lock member 282, extending between the rear end of the Phase I tube 268 and the outer wall of the burner tube 278 brings it closer to the rear end of the chamber 280.

A port 284 is provided in the wall of the tube 268 in Phase I, axially towards the rear of the lock member 272, communicating with the chamber 280, to connect a source of oxygen from the burner to the chamber 280. The burner tube internal 278 has a port 286 at its outer end, communicating with the interior thereof, to join it to a source of natural gas. A nozzle 288 is provided in the I Phase tube, intermediate in its length and in the front end of the chamber 280. The nozzle is preferably designed to provide an oxygen velocity in the range of about 60 to about 120 meters per second. in the mixing area of Phase I 290 within the front portion of the Phase I tube 268. An agitator 292 is provided at the front end of the chamber 280, immediately towards the rear of the nozzle 288, to impart a shaking action to oxygen entering area 290 of Phase I. Stirrer 292 may use helical fins having an angle of 10 ° to 45 ° with the longitudinal axis. A nozzle 294 is provided at the front end of the burner tube 278, terminating at its front end substantially coplanar with the front end of the oxygen nozzle 288. The nozzle 292 is preferably designed to provide a rate of injection of natural gas into the scale from approximately 60 to around 240 meters per second in area 290 of Phase I.

With the arrangement of the embodiment shown in Figure 6, the natural gas from the burner passes through port 286 in burner tube 278, and exits burner tube 278 through nozzle 294 in region 290 of the Phase I. Burner oxygen enters chamber 280 through port 284 and passes through agitator 292 and nozzle 288 in the area of Phase I into the front portion of tube 268 of Phase I. Oxygen is shake slightly by agitator 292 as it enters the area in Phase I and mixes with natural gas in the Phase I area. The oxygen-natural gas mixture is ignited by the heat of the reforming gases in the upper collector 8 to create a stable oxygen-fuel flame in the area of Phase I. Reformer natural gas and oxygen enter preheater 256 through their respective ports 274 and 276 and pass forward through the outer passage 264, recirculate back through of the internal passage 262, and again in the reverse direction and pass forward through the passage 270 in the mixing area 296 in Phase II immediately forward of the front end of the tube 268 of Phase I. In the area of the Phase II, the combustion products in Phase I (mainly CO2 and H2O) were mixed with the preheated natural gas and oxygen to initiate the reforming reaction in order to form the secondary reformed gases that then exit to the front end of the tube of mixing 252 in the upper collector 8.

In the embodiment of Figure 6, the reforming natural gas and oxygen are preheated before they enter the Phase II 296 area to improve reforming efficiency. As noted in the drawings, the preheater mixing tube 254 extends into the upper collector so that a substantial portion of the external surface of the preheater is exposed to the hot reformed gases to recover the heat thereof. The length to diameter ratio (L / D) of the mixing tube is kept on the scale from about 3 to about 9 depending on the availability of the space inside the reformed gas collector or other place such as the furnace pipe. axes to provide enough residence time of gases in Phase II to finish the reaction. The overall process of the present invention is divided into two Phases, Phase I and Phase II. In the mixing and combustion process of Phase I, a predetermined amount of oxygen from the burner and natural gas from the burner is mixed in an almost stoichiometric ratio (2: 1) and burned using a mixer from the first Phase. In this, a stable oxygen-fuel flame is created by an array of nozzles. The flame gases are then transported in a mixing tube of predetermined length and diameter. The mixing and reactions of Phase II take place in the mixing tube which extends well into the collector of the primary reforming gas.

The stoichiometric mixture of oxygen and natural gas in the area of Phase I is ignited initially by the contact of the hot primary reforming gases in the upper collector. Reformer gases in the upper collector are generally 926.6 ° C and 1 kg / cm2. Using a flame sensitive device 399 (see Figure 3) such as an ultraviolet ray, flame rod or thermocouple sensor, it can be verified that a good stable flame is extended and maintained in the mixing tube. The combustion products of combustible oxygen flame are mainly CO2 (33.3%) and H2O (66.6%) by volume, the peak temperatures of the flame products are in the range of 2204.4 ° C to 2482.2 ° C. The material of the mixing tube of the embodiments of Figures 4 and 5 (refractory duct steel, stainless steel or Inconel) is not designed to handle temperatures on this scale for long durations. Therefore, it is necessary that the mixing and reaction of Phase II begin as soon as possible. In the mixing and reaction process of Phase II, a predetermined amount of reformer natural gas and oxygen are introduced in Phase II in an oscillating configuration. In Phase II, a small amount of oxygen is mixed with the reforming natural gas as a catalyst to initiate the reforming reactions within the mixing tube. The agitation action of the injection of natural gas and oxygen in the area of Phase II has two functions. First, the stirring mixture provides cooling of the inner surface of the mixing tube and protects ta_t_¡_iy __________ to the thermal damage refractory duct mixing tube. Second, the reaction of Phase II, which uses the combustion products of Phase I, CO2 and H2O, which are at very high temperatures, will react more quickly with the reforming gases CH and O2 to produce the reformed gases (H2 and H2O). CO), as well as pre-heated methane (CH). The length-to-diameter ratio (L / D) of the length of Phase II of the mixing tube is selected by the reforming reaction residence time. The mixing tube acts as an insulation tube to prevent premature mixing of the Phase I combustion products and Phase II reforming gases with the external gases in the upper collector, resulting in substantially all the reforming oxygen which reacts inside the mixing tube. A ratio (L / D) of 3 to 9 is generally sufficient for good mixing between the products of Phase I and the reforming gases of Phase II. Some of the methane in the natural gas provided for the reaction in Phase II is not reformed. This gas becomes gas enriched by the shaft furnace. The provision of natural enrichment gas in the second phase allows effective control of the temperature and carbon content of the total reformed gas mixture that goes to the shaft furnace piping, so control is provided by the reformer of this invention of the carburization reaction in the reduction zone of the shaft furnace. Varying the amount of RIMMMMMÉMMM If excess natural gas is supplied to Phase II, the amount of natural enrichment gas present in the total reformed gas supply (primary and secondary) may vary. The composition of the gas produced by the oxygen-fuel reinforcing reformer of the present invention is very similar to the gases produced by the reformer in both reducing to oxidizing ratios (H2 + CO / H2O + CO2 and the H2 / CO ratio. Therefore, reformed gases of similar quality are generated by the apparatus and process of the present invention with the additional benefit of having preheated methane (3% up to 4% by volume as natural enrichment gas) in the total reformed gas composition. The process and apparatus of the present invention thus minimize the need for injection of cold enrichment methane (natural gas) into the reformed gas before the pipe., the provision of excess natural gas in the mixing in Phase II also allows a good control over the global reforming gas temperature as well as the provision of a cooling medium for the material of the mixing tube. Table I below shows an example of relative process gas flow regimes and direct reduction iron (HRD) production regimes for a normal DRI production plant using primary reformer gas from the plant reformer. The table also exhibits simple calculations on the amount of the additional reformed gas needed to be produced by the oxygen-fuel booster reformer (RROC) of the present invention for the overall effect of increasing the rate of HRD production. The values in Table I are calculated for an increase of 5 tons / hour in the production (or metallization regime) by an axle furnace operating at 70 tons / hour. The flow rates used for the gases in Table I are given in 0.09 m3 per hour normal (0.09 mchn). Table I For simplicity, the amount of RROC reformed gas in Table I was calculated using the following chemical reaction: CH4 + 1 / 2O2? CO + 2H2 This is a simplistic (and global) representation of the combined Phase I and Phase II reactions of the process described here. As can be seen by this reaction equation, a volume of reagents produces 2 volumes of reformed gases. The RROC process is a two-phase process in which total natural gas and total oxygen are burned in a Phased form and not all together as indicated by the above chemical equation. Table I assumes that the composition of current (existing) reformed gases (dry volume) is H2 = 58%, CO = 38%, CO2 = 2.5%, CH4 = 0.5% and N2 = 1.0%. In addition, it is also assumed that the process of reforming RROC is 100% efficient and that all the reforming natural gas and oxygen were converted into CO and H2. It should be understood that the actual process is not 100% efficient and can vary between about 50 and about 90% reforming efficiency. Table II below shows the scales and preferred percentages of the natural gas and oxygen flow regimes of the operation in Phase I and Phase II of the oxygen-fuel booster reforming process. The flow regimes are given as guidelines and can vary significantly from one HRD plant to another depending on the temperature, pressure and composition of the primary reforming gases in the plant and the overall operation of the plant. For the purpose of Table II, it is assumed that an increase of 5 ton / hour is desired in the production of HRD and the basic process requirement of Table I is in effect. Table II Using Table II as reference, an example of the operation of the process and apparatus of the present invention is to set the ignition of the burner in Phase I to approximately 25% of the total natural gas used by the oxygen-fuel booster reformer system and the oxygen of the burner is close to the stoichiometric ratio. Reformer natural gas graduates to 75% of the total natural gas used in the process. The reforming oxygen is graduated to 20% of the total oxygen used by the system. The reformed gases produced by the RROC system indicated in Tables I and II are graduated to 5% of the volume of total reformed gas. The natural enrichment gas shown in Table II, but, for example, can be graduated at 7,500 standard cubic meters per hour (mchn), approximately half compared to natural reformer gas. The enrichment natural gas flow regime can be varied by the plant operator to control the global reformed gas temperature and carbon content for the HRD process. Depending on the design of the Phase I (burner) mixer, the peak temperatures of the oxygen-natural gas products Phase I combustion (33% CO2 and 66.6% H2O) are relatively high and can vary anywhere from about 1926.6 ° C to about 2482.2 ° C. The variance is due to the design of the Phase I mixer. If the oxygen-natural gas mixing is perfect, an adiabatic flame gas temperature (theoretical maximum) is obtained. If the nozzle-mixer burner is used, a relatively colder flame gas temperature of about 1926.6 to about 2204.4 ° C. The mixing process and mixer of Phase I should be carefully selected based on the material of mixing tubes under construction. A refractory duct mixing tube can allow higher peak flare gas temperatures, while a steel alloy mixing tube will require relatively lower temperatures from a nozzle-mix oxygen-fuel burner for Phase I mixing. In Phase II, the natural gas and oxygen reformers were injected with a rotating motion around the products of Phase I combustion. The basic reforming reactions for Phase II are the following: CH4 + CO2? 2CO + 2H2 and CH4 + H2O - CO + 3H2. If proper mixing of the reformed gases is achieved by the use of a stirrer and a mixing tube with the appropriate length to diameter ratio, then the products of the Phase II reaction will contain very little CO2 and / or unused H2O. The higher temperature of CO2 and H2O in Phase II, is beneficial to increase the reaction regimes and production of CO and H2. The injection of natural enrichment gas in Phase II is beneficial to improve the mixing and use of H2O and CO2 for the reforming actions, the reduction of the temperature of Phase I for the material capacity of the mixing tube, and the preheating of natural enrichment gas using thermal energy from Phase I. A window of good temperature for mixing in Phase II and the reformation is between approximately 982.2 and around 1926.6 ° C. The output of Phase II consists of the reformed gases (CO + H2), preheated natural gas and CO2 and H2O at rest or without reacting. Considering Table I and Table II for OBFR flows, at a peak gas temperature of Phase I calculated from 1926.6 ° C. This is an increase of -1.1 ° C in temperature due to the OBFR process. The oxygen-fuel reinforcement reformer and process of the present invention provides a means to control the total amount of reformed gases that are supplied, the temperature of the global reformed gases (primary and secondary) and the amount of natural gas enrichment present in global reformed gases. By varying the flow of natural gas to the Phase I burner, maintaining the oxygen supplied to it in an almost stoichiometric ratio and proportionally varying the flow of natural gas to Phase II, the amount of reformed gas produced by the oxygen-reinforcing reformer. fuel may vary, AMteaMl which in turn varies the total amount of reformed gas that is being supplied. If the flow rate of the natural gas to the Phase I burner varies and the oxygen supply to it also varies to maintain the stoichiometric ratio and no change is made to the gas flow regimes to Phase II, the temperature of the reformed gas resulting from oxygen-fuel booster reformer. The temperature of the reformed secondary gases of the oxy-fuel booster reformer increases with an increase in the natural gas flow rate of the burner and will decrease with a decrease the natural gas flow rate of the burner. The increase or decrease in the temperature of the secondary gases will increase or decrease the temperature of the entire global reformed gas supply when mixed with the primary reformed gases. If the flow of natural gas to Phase II is varied, without any change in the gas flow regimes to the Phase I burner, there will be a change in the amount of natural enrichment gas in the secondary reformed gas produced by the Oxygen-fuel booster reformer and therefore a change in the overall amount of natural gas enrichment in the global reformed gas supply. However, in this case, a change in the flow regimes for Phase II produces a change in the temperature of the secondary reformed gas. An increase in ___ * __, _____________, ^^^^ _ flow regime of natural gas to Phase II will decrease the temperature, while a decrease will cause a rise in temperature. Therefore, by selectively varying the gas flow rates for Phase I and / or Phase II, the amount of reformed gas, the temperature of the reformed gas and the amount of enrichment gas of the global reformed gas supply can be controlled without the need for any change in the gas reformer operation of the main plant or the use of other controls. Proper control of the temperature of the reformed gas flowing to the shaft furnace is important to maintain good quality of the reduced iron directly avoiding agglomeration at higher gas temperatures. The most efficient operation is to operate at the highest temperature that can be tolerated without the agglomeration occurring. Although the invention has been described above with reference to the specific embodiments thereof, it is clear that many changes, modifications and variations can be made without departing from the concepts described herein. Accordingly, it is intended to encompass all such changes, modifications and variations that fall within the scope of the appended claims.

Claims (30)

1. CLAIMS 1. A method to generate reformed gases, said method characterized because: a. burns a mixture of a first supply of a gaseous hydrocarbon and oxygen in a first phase to provide flame gases; b. passes the flame gases in a second Phase; c. injects a second supply of a gaseous hydrocarbon and oxygen in the second Phase; and d. causes the flame gases to react with the second supply of the gaseous hydrocarbon in the second Phase to produce reformed hydrogen and carbon monoxide. The method of claim 1, further characterized by the fact that said gaseous hydrocarbon is natural gas, methane, or propane and the oxygen is commercial grade oxygen, air or mixtures thereof. 3. The method of claim 2, further characterized by the fact that combustion in the first Phase produces carbon dioxide and water which are passed in the second Phase. 4. The method of claim 2, further characterized by the fact that the second Phase is in the mixing tube. The method of claim 4, further characterized by injecting the second supply of gaseous hydrocarbon and oxygen into the mixing tube in an oscillatory configuration. 6. The method of claim 2, further characterized in that it mounts the mixing tube at a location so that it is surrounded by the existing reformed gases and causes said reformed hydrogen and carbon monoxide produced to pass from the mixing tube to the existing gases. The method of claim 6, further characterized in that it uses the heat of the existing reformed gases to cause the first supply of the gaseous hydrocarbon and oxygen to ignite in the first Phase. 8. The method of claim 2, further characterized by cooling the first phase in which combustion occurs. The method of claim 2, further characterized by preheating the second supply of the second supply of the gaseous hydrocarbon and oxygen before it enters the second Phase. The method of claim 2, further characterized by the preheating of the second supply of the gaseous hydrocarbon and oxygen before they enter the second Phase and the use of the preheated gaseous hydrocarbon and oxygen before its passage in the second Phase to cool the first phase. The method of claim 1, used to supplement the amount of reformed gas used in direct reduction iron plants where the primary reformed gas is supplied to a furnace from a primary reformer and passed through the iron ore to produce iron; said method of claim 1, further characterized by the injection of the reformed hydrogen and carbon monoxide in the primary reformed gas route to the furnace. The method of claim 11, further characterized in that the gaseous hydrocarbon is natural gas, methane, or propane and the oxygen is commercial grade oxygen, air or mixtures thereof. The method of claim 12, further characterized by the fact that the second Phase is in a mixing tube extending in the path of the primary reformed gas being supplied to the furnace. The method of claim 12, further characterized by injecting the second supply of the gaseous hydrocarbon and oxygen into the mixing tube in an oscillatory configuration. The method of claim 12, further characterized in that said mixing tube is mounted in an existing upper collector containing reformed gases of said primary reformer, and further comprises the use of the heat of the existing reformed gases to initiate the initial combustion of said first supply of the gaseous hydrocarbon and oxygen in said first Phase. The method of claim 12, further characterized by injecting excess gaseous hydrocarbon in said second phase to provide natural enrichment gas for use in the direct reduction iron process. 17. The method of claim 16, further characterized in that it controls the amount of enrichment natural gas in the reformed gas passing said furnace by selectively varying the flow rate of said second supply of the gaseous hydrocarbon to said second phase 18. The method of claim 12, further characterized in that controls the temperature and / or amount of the reformed gas passing to said furnace by selectively varying the flow rates of the first supply of gaseous hydrocarbon and oxygen to the first phase and / or the flow rate of the second supply of said gaseous hydrocarbon to the second phase. 19. A gas reformer to generate reforming gases characterized by: a. a burner to burn a mixture of a first supply of a gaseous hydrocarbon and oxygen in a first phase to produce combustion products; b. an elongated mixing tube that provides a second phase in which said combustion products are transported, and c. an injector for injecting a mixture of a second supply of a gaseous hydrocarbon in said second phase for reaction with the combustion products of said first phase in order to produce reformed hydrogen and carbon monoxide. .. ^. ^ l-ß-llfc_? ß ^ _? i-líilÉ fciiilÉiliilliií? ta ___-- 20. The gas reformer of claim 19, further characterized by the fact that said gaseous hydrocarbon is natural gas, methane, or propane, and said oxygen is commercial grade oxygen, air, or mixtures thereof. 21. The gas reformer of claim 19, further characterized by the fact that said burner includes a Venturi mixer that includes a venturi having a diverging section opening in said mixing tube, a chamber around said Venturi to receive the second supply of the gaseous hydrocarbon and oxygen, the chamber opening in a mixing tube downstream of the divergent section of said venturi. 22. The gas reformer of claim 21, further characterized by an agitator in the chamber opening in the mixing tube for imparting an oscillatory movement to said second supply of said gaseous hydrocarbon and oxygen as it enters the mixing tube. 23. The gas reformer of claim 21, further characterized by the fact that said mixing tube has a refractory conduit. 24. The gas reformer of claim 19, further characterized in that said burner includes a tube having a nozzle at the initial end thereof for receiving said first supply of the gaseous hydrocarbon, a first chamber surrounding the tube for receiving the first supply of oxygen, and a combustion chamber forward of the nozzle opening in the mixing tube, a tubular cooling liner surrounding said combustion chamber, the cooling liner having inlet and outlet ports for passage of cooling fluid in and out of said cooling liner, the nozzle of said burner tube and the chamber opening in said combustion chamber through the passage of the first supply of the gaseous hydrocarbon and oxygen into the combustion chamber to burn in the same, a second chamber for receiving the second supply of said gaseous hydrocarbon and oxygen and having an opening in said mixing tube downstream of the combustion chamber for the passage of the second supply of the gaseous hydrocarbon and oxygen in the mixing tube to be mixed with combustion products of said combustion chamber. The gas reformer of claim 24, further characterized by a stirrer in the opening of the second chamber in the mixing tube in order to provide an oscillating movement to the second supply of the gaseous hydrocarbon and oxygen as it enters the mixing tube. 26. The gas reformer of claim 25, further characterized by a stirrer in the opening of the first chamber in the combustion chamber for imparting an oscillatory motion to the first oxygen supply as it enters the combustion chamber. 27. The gas reformer of claim 19, further characterized by the fact that the burner includes a __lia_¡_ita__I ___ I___u burner tube for connection to a source of the first gas supply and having a nozzle at its downstream end, a chamber surrounding the burner tube for connection to a source of the first supply of oxygen and having a nozzle at its downstream end, the nozzles opening in a combustion chamber, the mixing tube having a plurality of annular passages extending longitudinally axially exceeding the mixing tube, said passages including a first external passage extending frontally in the mixing tube, a return passage connected to said external passage and that subsequently extending into the mixing tube, and an internal passage connected to said return passage at its rear end and opening in the mixing tube at its initial end at a point spaced axially posterior from the initial end of the mixing tube, the internal passage surrounding said combustion chamber, the external passage having means of entry to the second supply of the gaseous hydrocarbon and oxygen in the passage adjacent to its rear end, the second supply of the gaseous hydrocarbon and oxygen passing through the passages and entering to said mixing tube at the initial end of the internal passageway downstream of the combustion chamber. The gas reformer of claim 27, further characterized in that said chamber has a stirrer in its opening upstream of said nozzle to impart an oscillatory movement to the first oxygen supply passing through said nozzle in the combustion chamber. 29. The gas reformer of claim 19, used to generate supplemental reformed gases in a direct reduction iron plant wherein the primary reformed gas is supplied through a path from a primary reformer to an oven and passing through of the iron ore to produce iron; said gas reformer of claim 1 further characterized by said mixing tube that opens in the path of the reformed gases to said furnace, and the reformed hydrogen and carbon monoxide leave said mixing tube and enter the path of the path of said reformed gases. 30. The gas reformer of claim 29, further characterized by the fact that the gaseous hydrocarbon is natural gas, methane, or propane, and said oxygen is commercial grade oxygen, air, or mixtures thereof.