WO2008005460A2

WO2008005460A2 - Controlling jet momentum in process streams

Info

Publication number: WO2008005460A2
Application number: PCT/US2007/015410
Authority: WO
Inventors: William Thoru Kobayashi; M. Mushtaq Ahmed; James Patrick Meagher; Lee Jonathan Rosen
Original assignee: Praxair Technology, Inc
Priority date: 2006-07-06
Filing date: 2007-07-03
Publication date: 2008-01-10
Also published as: US20080006225A1; WO2008005460A3

Abstract

A gaseous process stream (11) that can be directed into a workspace (22) or toward a workpiece is formed by feeding fuel (5), oxidant (6) and process material (10) into a thermal nozzle (1). The fuel combusts in the thermal nozzle with the oxidant and with combustible components, if any, of the process material, to form the gaseous process stream which is emitted from the thermal nozzle at high and controllable velocity and momentum.

Description

CONTROLLING JET MOMENTUM IN PROCESS STREAMS

Field of the Invention

This invention is useful in industrial processes wherein gaseous streams, especially heated streams, are directed into workspaces or toward workpieces at high velocity and momentum.

Background of the Invention

In many industrial processes, such as heat treatment, metal refining, process heaters, and other processes examples of which are described herein, one or more gaseous streams are injected into a workspace (such as a combustion chamber or heat exchanger) or toward a workpiece (which can be solid or liquid matter such as a solid metal object being heated, or a liquid such as a water treatment pond or a vat of molten metal). The effect provided by such gaseous streams is usually more favorable if the gaseous stream is provided at high velocity and momentum, but it has generally been understood that attaining the desired high velocity and momentum requires providing the gaseous stream at high pressures.

Since supplying the gaseous stream at high pressure incurs high expenditures of energy and money, there is a need for a mode of providing the gaseous streams at increased velocity and momentum without having to raise the pressure at which it is supplied. In addition, as the ability to control the velocity and momentum of the gaseous streams is usually desirable, a mode of providing the gaseous streams from a low-pressure supply while being able to control the velocity and momentum is also needed.

Brief Summary of the Invention

The various aspects of the present invention described herein provide ways to satisfy these needs.

One aspect of the present invention is a method of generating a gaseous process stream and providing it through an outlet at a controllable velocity and momentum, comprising (A) providing a chamber that has a fuel inlet connected to a source of fuel, an oxidant inlet that is connected to a source of oxidant, a process material inlet that is connected to a source of process material which feeds said process material into said chamber at a first temperature, and an outlet through which gas can pass from the chamber,

(B) determining the velocity and momentum that the gaseous process stream is to have as it passes from the chamber through said outlet,

(C) determining the temperature that the gaseous process stream is to have as it passes from the chamber through said outlet in order to have said velocity and momentum,

(D) determining the amounts of fuel and oxidant that must be combusted in the chamber to generate sufficient heat of combustion to raise the temperature of said process material from said first temperature to the temperature determined in step (C), and (E) feeding the amounts of fuel and oxidant determined in step (D) into said chamber, feeding said process material into said chamber, and combusting said fuel with said oxidant and with combustible components, if any, in said process material to form said gaseous process stream, and passing said gaseous process stream through said outlet at the temperature determined in step (C). Another aspect of the present invention is a method of generating a gaseous process stream and providing it through an outlet at a controllable velocity and momentum, comprising

(A) providing a chamber that has a fuel inlet connected to a source of fuel, an oxidant inlet that is connected to a source of oxidant, a process material inlet that is connected to a source of process material which provides said process material into said chamber at a first temperature, and an outlet through which gas can pass from the chamber,

(B) determining the velocity and momentum that the gaseous process stream is to have as it passes from the chamber through said outlet, (C) determining the temperature that the gaseous process stream is to have as it passes from the chamber through said outlet in order to have said velocity and momentum, (D) determining the amounts of fuel and oxidant that must be combusted in the chamber to generate sufficient heat of combustion to raise the temperature of said process material from said first temperature to the temperature determined in step (C),

(E) feeding the amounts of fuel and oxidant determined in step (D) into S said chamber, feeding said process material into said chamber, and combusting said fuel with said oxidant and with combustible components, if any, in said process material to form said gaseous process stream, and passing said gaseous process stream through said outlet, and

(F) controlling the velocity and the momentum of said gaseous process0 stream as it passes through said outlet by controlling the amounts of fuel and oxidant fed into said chamber in step (E) and combusted therein.

Another aspect of the present invention is a method of operating an apparatus, comprising

(A) providing apparatus that comprises a device which emits a first S gaseous process stream into a workspace or toward a workpiece,

(B) emitting a first gaseous process stream from said device into said workspace or toward said workpiece;

(C) providing a chamber that has a fuel inlet connected to a source of fuel, an oxidant inlet that is connected to a source of oxidant, a process material inlet that is0 connected to a source of process material, and an outlet through which a second gaseous process stream can pass from the chamber into said workspace or toward said workpiece;

(D) feeding fuel and oxidant into said chamber, feeding said process material into said chamber, and combusting said fuel and oxidant with combustible5 components, if any, in said process material to form said second gaseous process stream, and passing said second gaseous process stream through said outlet into said workspace or toward said workpiece, wherein said second process stream intersects said first gaseous process stream. Such intersection can comprise simple intermingling of the first and second process streams, but preferably also comprises entrainment of the first process stream

(and, generally, also some of the surrounding atmosphere, especially when the streams are fed into a workspace). Another aspect of the invention is a method of modifying an apparatus, comprising

(A) providing apparatus that comprises a device which emits a first gaseous process stream into a workspace or toward a workpiece; (B) adding to said apparatus a chamber that has a fuel inlet connected to a source of fuel, an oxidant inlet that is connected to a source of oxidant, a process material inlet that is connected to a source of process material, and an outlet through which a second gaseous process stream can pass from the chamber into said workspace or toward said workpiece; (C) feeding fuel and oxidant into said chamber, feeding said process material into said chamber, and combusting said fuel with said oxidant and with combustible components, if any, in said process material to form said second gaseous process stream, and passing said second gaseous process stream through said outlet into said workspace or toward said workpiece. A further aspect of the present invention is a method of modifying an apparatus, comprising

(A) providing apparatus that comprises a device which emits a first gaseous process stream into a workspace or toward a workpiece;

(B) adding to said apparatus a chamber that has a fuel inlet connected to a source of fuel, an oxidant inlet that is connected to a source of oxidant, a process material inlet that is connected to a source of process material, and an outlet through which a second gaseous process fluid can pass from the chamber into said workspace or toward said workpiece;

(C) determining the velocity and momentum that said second process stream is to have as it passes from the chamber through said outlet,

(D) determining the temperature that said second process stream is to have as it passes from the chamber through said outlet in order to have said velocity and momentum,

(E) determining the amounts of fuel and oxidant that must be combusted in the chamber to generate sufficient heat of combustion to raise the temperature of said second process stream to the temperature determined in step (D), (F) feeding the amounts of fuel and oxidant determined in step (E) into said chamber, feeding said process material into said chamber, and combusting said fuel with said oxidant and with combustible components, if any, in said process material to form said second process stream, and passing said second process stream through said outlet into said workspace or toward said workpiece.

Brief Description of the Drawings

Figure 1 is a cross-section view of a thermal nozzle which can be employed in practicing the present invention. Figure 2 is a cross-section view of one illustrative embodiment of apparatus with which the present invention is useful.

Detailed Description of the Invention

The present invention is useful in any apparatus wherein a stream of gas, particularly gas at a temperature higher than ambient, is injected at high velocity and high momentum into a workspace oτ toward a workpiece. Workspaces generally comprise any sort of enclosed or partially enclosed volume, and are usually provided with an outlet that is permanently open or that can be intermittently opened and closed, for allowing gas to leave from the enclosure. Examples of such workspaces include combustion chambers, such as incinerators, furnaces for combusting fuel to generate heat that is converted into steam (which can then be converted into electric power), process heaters wherein combustion is carried out within a chamber to generate heat which is transferred through the walls of the chamber to product contained in or flowing through piping to heat or evaporate the material or to promote chemical reactions carried out within the piping. Other examples of workspaces include furnaces to vaporize or refine metal, and plasma spraying and coating operations.

The present invention is also useful in embodiments in which a gaseous stream is directed toward a workpiece, even if the workpiece is not contained within a workspace. Examples of embodiments wherein the gaseous stream is directed toward a workpiece include refining of steel and other metals, wherein the gaseous stream is directed toward a surface of molten metal (for instance, in the refining of the metal); apparatus wherein a stream of gas is directed toward a slab of metal, such as a slab of metal moving along a conveyor and being heated; and systems wherein a stream of gas is directed toward a pond of wastewater. Other examples of embodiments wherein the gaseous stream is directed toward a workpiece not necessarily enclosed within a workspace include operations wherein a stream is directed toward a surface to remove material from the surface, whether to clean it or for other material removal purposes.

Referring to Figure 1, thermal nozzle 1 is shown in cross-section. Thermal nozzle 1 includes chamber 3, composed of (or lined with) material that can withstand the temperatures that are generated within chamber 3. Process material inlet 4 is provided through which stream 10 of process material passes from a source thereof into chamber 3. The process material stream 10 is fed through inlet 4 at low pressure, preferably below 20 psig, and more preferably below 10 psig. Fuel inlet 5 is provided for fuel to enter into chamber 3 from a source of the fuel. Oxidant inlet or inlets 6 permit oxidant to enter into chamber 3 from a source of the oxidant. Preferably, as shown in Figure 1, fuel inlet S and oxidant inlet or inlets 6 are components of a burner. The oxidant and fuel fed into the interior of chamber 3 combust therein in flame 7. The gaseous stream produced by the combustion of the fuel with the oxidant (and with any combustible component of the process material, if the process material contains any combustible components), and by the intermixing in the gas phase of the products fed to chamber 3 and of combustion products, pass out of chamber 3 through outlet 8 as stream 11.

Outlet 8 can comprise a single opening, or more than one opening. If outlet 8 comprises more than one opening, the openings can be of the same size and shape or of differing sizes and shapes, and they can all have the same axial orientation (that is, streams passing through them are parallel), or they can have different axial orientations. For example, one preferred outlet 8 would comprise 2 to 12 openings all of whose axes diverge away from a central axis so that gaseous streams passing through the openings form a conical pattern diverging such that its narrow end is at outlet 8.. Suitable fuel fed through fuel inlet 5 for combustion in thermal nozzle 1 includes any combustible hydrocarbonaceous material, preferably liquid or gaseous. Examples include natural gas, methane, and fuel oil.

Suitable oxidants fed through inlet 6 include streams containing less than 21 vol.% oxygen, air, oxygen-enriched air containing more than 21 vol.% oxygen, and oxygen in commercially available purities preferably 90 vol.% or higher.

The process material that is fed into chamber 3 through inlet 4 can be in the solid (preferably in flowable particulate form), liquid, or gaseous state, or can be in any two or all three of such states. The process material fed through inlet 4 can completely comprise material which is inert (not capable of being combusted), it can comprise a mixture of inert material in mixture with combustible material, with oxygen, or with both combustible material and oxygen, and it can completely comprise oxygen, combustible material, or a mixture of oxygen and combustible material. Examples of combustible material that the process material can comprise in whole or in part include the fuels described above that can be fed through fuel inlets S, as well as gas from other chemical processing refinery operations, from pressure swing adsorption units, steam methane reforming units, and the like.

The amounts of process material fed through inlet 4, the amount of fuel fed through fuel inlet S, and the amount of oxygen in the oxidant fed through oxidant inlet or inlets 6, relative to each other, are provided so as to attain (as a result of the combustion in chamber 3) the desired composition of the gaseous stream that is provided from the thermal nozzle 1. That is, if stream 1 1 is to contain oxygen or fuel, as the case may be, in order for instance to participate in combustion in the workspace or near a workpiece, then the amounts of oxygen and fuel that are fed into the thermal nozzle 1 in all feed streams (including in the process material stream 10) must be proportioned so that following the combustion that occurs within thermal nozzle 1 there remains an excess of uncombusted oxygen, or uncombusted fuel as the case may be, that exits in stream 11 and participates as desired in further reaction (such as combustion). Thus, it should be recognized that when the process material is fed into the thermal nozzle, the composition of the gaseous stream 11 that emerges from the thermal nozzle will depend on whether any component of the process material combusts with the combusting fuel and oxidant. In some embodiments of this invention, the incoming process material is entirely or partially liquid, is entirely or partially solid, or is a mixture of gas and liquid, gas and solid, liquid and solid, or gas and liquid and solid. In any such embodiments, any liquid that is fed will be vaporized in chamber 3, and any solids that are fed will melt and vaporize. Thus, it should also be recognized that in any such embodiments, the determination of the amounts of fuel and oxygen to feed into thermal nozzle 1 must take into account the amount of heat required for melting of solids and for vaporization of liquid (including liquid as fed, and liquid obtained by melting of solids) so that the combustion that occurs within thermal nozzle 1 will produce a gaseous process stream and will provide that stream exiting the outlet at the desired temperature.

The temperature of the stream that exits the thermal nozzle is generally in the range of 100⁰F to 3000⁰F, preferably 300⁰F to 3000⁰F. The velocity of this stream is generally 100 to 3000 feet per second.

Among the many useful advantages of the present invention are those that pertain to the practice of the invention in providing a gaseous stream into a workspace. These advantages include improved mixing and recirculation of the gaseous atmosphere in the workspace, improved staging of combustion carried out in the workspace (which provides improved control to minimize emission of nitrogen oxides ("NOx")), and enhanced heat transfer between the gaseous stream and the workspace atmosphere, and between the gaseous stream and other gaseous streams fed by auxiliary injectors or burners. These advantages have heretofore been provided by high momentum jets obtained by increasing the mass flow rate and/or the supply pressure of the gaseous stream.

The present invention, on the other hand, provides these advantages by converting thermal energy into kinetic energy to attain high injection velocities even at relatively low gas supply pressure. The injection velocity can be varied at any given supply pressure, permitting control of other properties such as momentum, entrainment ratio, and the like, without changing nozzles or using a variable nozzle. With this invention the gas stream momentum and other characteristics such as the entrainment ratio can be controlled while the process is in operation, by adjustment of the feed rates of the fuel and oxidant into the thermal nozzle and the ratio of those feed rates. There is no need to replace nozzles or other type of injection devices, or to increase the supply pressure of the incoming process material stream, to achieve the desired results.

S The present invention is also advantageous in processes wherein the gaseous stream fed from the thermal nozzle is to react with other compounds in the atmosphere within the workspace or near the workpiece, or with other compounds fed by auxiliary injectors (whether or not combustion is taking place). The desired reactivity is increased by the high temperature of the gaseous stream fed from the0 thermal nozzle.

The present invention can be applied to other processes that do not involve combustion, such as: hot oxidant injection at high velocity into a tilemaking furnace, to reduce S black core formation in refractory and ceramic tile production processes; hot oxidant injection at high velocity into coke beds; injection of hot oxidant and/or inert gas at high velocity into molten metal; injection of hot nitrogen, argon, or other inert gas, or mixtures of inert gases, into heat treating processes; 0 injection of reactive gases into heat treating processes; injection of hot oxidant into wastewater treatment processes.

The higher injection velocity and higher temperature of the gaseous stream fed from the thermal nozzle provided by the present invention can bring benefits to the5 various applications of the invention, such as enhancing entrainment with the gases within a workspace or adjacent to a workpiece, or with other gases injected into the workspace or toward the workpiece; enhancing recirculation of the gases within a workspace or adjacent to a workpiece, or of other gases injected into the workspace or toward the workpiece;; enhancing jet penetration into a body of liquid, such as a pool of molten metal or a wastewater treatment pond, or into a bed of solids such as coke bed; enhancing reactivity, due to the high temperature and high entrainment and recirculation; and decreasing the gas stream flow rate to impart the same momentum as a lower temperature stream resulting in comparable process performance with reduced oxygen consumption and thus improved process economics.

The advantages provided by the present invention follow from the velocity and momentum of the gaseous stream being supplied from the thermal nozzle, and from the ability to adjust the velocity and momentum. These, in turn, are based on the temperature of that stream and from the ability to control that temperature. The velocity and momentum that the stream produced from the thermal nozzle should have, in order to provide the desired properties in the application for which the invention is being practiced, can be determined by calculations or by experimentation for a given apparatus, by varying the temperature of that stream and varying the rates at which the fuel, the oxidant, and the process material stream are fed to the thermal nozzle, until the gaseous process stream provided by the thermal nozzle exhibits the desired velocity and momentum.

A procedure to determine the conditions for operating a thermal nozzle in a given application, and for sizing the thermal nozzle for the application, is: determining the velocity and momentum that the gaseous process stream is to have as it passes from the chamber through said outlet, determining the temperature that the gaseous process stream is to have as it passes from the chamber through said outlet in order to have said velocity and momentum, determining the amounts of fuel and oxidant that must be combusted in the chamber to generate sufficient heat of combustion to raise the temperature of said process material to the temperature determined in the preceding step, taking into account heat if any that must be provided to vaporize material fed as liquid and/or to melt and then vaporize material fed as solids; feeding the amounts of fuel and oxidant determined in the preceding step into said chamber, feeding said process material into said chamber, and combusting said fuel with said oxidant and with combustible components, if any, in said process material to form said gaseous process stream, and passing said gaseous process stream through said outlet.

Figure 2 illustrates one representative embodiment of apparatus with which S the present invention can be practiced. This example illustrates application of the present invention to a workspace, which here is a combustion chamber of the type that is known as a process heater in chemical processing plants and refineries. The heat generated by combustion carried out within the combustion chamber is transferred through the walls of the piping within the combustion chamber to the contents of the0 piping, to heat the contents and if desired to provide heat that promotes an endothermic reaction such as in steam methane reforming carried out with reactants passing in that piping.

In conventional practice, heat is provided to the combustion chamber from air- fuel burners placed at the bottom of the radiant section of the chamber, but due to the S characteristics of the flame promoted by air-fuel burners most of the heat transfer occurs at the upper end of the combustion chamber. When an increase in the throughput rate of material being heated in the aforementioned piping is desired, the overall firing rate at the air-fuel burners has to be increased but increasing the overall firing rate makes the flame much longer and does not promote the desired increase in0 heat transfer.

The present invention is implemented in this illustrative unit in order to promote a desired throughput increase and to enhance the heat transfer closer to the bottom of the combustion chamber, by providing high momentum injection of oxygen or fuel. 5 In Figure 2, thermal nozzle 1 is provided in the bottom of the process heater's housing 21 which encloses workspace 22. Thermal nozzle 1 emits gaseous process stream 11 into workspace 22. Housing 21 is also provided with flue 24 to permit gases to exit from workspace 22. Typically, one or more heat exchangers can be provided through which the flue gases pass to transfer heat from the flue gases to material flowing through the heat exchanger. Unit 23 represents such a heat exchanger. Apparatus with which the present invention is useful may contain, in addition to the thermal nozzle employed in the present invention, one or more other injectors of conventional design, such as burners or nozzles, which also emit one or more streams of gaseous material into the workspace or toward the workpiece. The apparatus of Figure 2 is illustrative of such apparatus. Thus, housing 21 in this embodiment is also provided with auxiliary burners 25 which also emit gaseous streams 26 (in this case, flame and combustion products) into workspace 22. Fuel stream S and oxidant stream or streams 6 are provided to thermal nozzle 1 and, in this embodiment, to auxiliary burners 25. Process material stream 10 is also provided into thermal nozzle 1. In the embodiment illustrated in Figure 2, common fuel 5 is provided to the thermal nozzle 1 and to the auxiliary burners 25, and oxidant is provided from a common source to thermal nozzle 1 and to auxiliary burners 25. In other embodiments, the composition of the fuel and the composition of the oxidant fed to the thermal nozzle and to each of any auxiliary burners or other injectors of gaseous streams can be different in the different streams.

In other embodiments, other nozzles can be provided (instead of or in addition to burners 25) which inject gaseous fluid, whether heated or not, into workspace 22. That is, there is no requirement that gaseous process streams that are fed into a workspace, or toward a workpiece, in addition to the process stream 11 from thermal nozzle 1, must be formed by combustion. Where burners 25 are provided, the fuel and oxidant are provided to each of them in appropriate amounts to enable combustion to occur at the burners, and for the combustion preferably to be maintained at those burners.

In the practice of the present invention, one or more than one thermal nozzle 1 can be added to the apparatus. One or more than one thermal nozzle 1 can replace auxiliary burners or injectors that were already present. Alternatively, the thermal nozzle or nozzles 1 can simply be added to what is already present in the apparatus, without removing any other burner or injector.

The appropriate velocity and temperature and feed rates can be determined by the sequence of steps described above. Here, though, where it is desired that the stream 11 from the thermal nozzle should intersect by enrrainment with one or more streams from other injectors such as burners 25, the desired velocity of stream 11 can be determined or derived from correlation of the entrainment ratio (defined as the number of surrounding atmospheres entrained by the stream) against distance from the opening, for different temperatures of the stream 11. With the temperature thus known, the amount of oxygen and fuel required can be determined by straightforward thermodynamic calculations. The particular location of outlet 8, as well as the orientation of outlet 8, are determined based on the geometry and dimensions of the chamber 22 into which the gas is fed, and on the location of the process heating tubes and the location of the burners.

Claims

WHAT IS CLAIMED IS:

1. A method of generating a gaseous process stream and providing it through an outlet at a controllable velocity and momentum, comprising S (A) providing a chamber that has a fuel inlet connected to a source of fuel, an oxidant inlet that is connected to a source of oxidant, a process material inlet that is connected to a source of process material which feeds said process material into said chamber at a first temperature, and an outlet through which gas can pass from the chamber, 0 (B) determining the velocity and momentum that the gaseous process stream is to have as it passes from the chamber through said outlet,

(C) determining the temperature that the gaseous process stream is to have as it passes from the chamber through said outlet in order to have said velocity and momentum, 5 (D) determining the amounts of fuel and oxidant that must be combusted in the chamber to generate sufficient heat of combustion to raise the temperature of said process material from said first temperature to the temperature determined in step (C), and

(E) feeding the amounts of fuel and oxidant determined in step (D) into0 said chamber, feeding said process material into said chamber, and combusting said fuel with said oxidant and with combustible components, if any, in said process material to form said gaseous process stream, and passing said gaseous process stream through said outlet at the temperature determined in step (C).

2. A method according to claim 1 wherein the process material comprises gas.

3. A method according to claim 1 wherein the process material comprises liquid.

4. A method according to claim 1 wherein the process material comprises solid.

5. A method according to claim 1 wherein the process material comprises combustible matter.

6. A method according to claim 1 wherein the process material comprises 5 oxygen.

7. A method according to claim 1 wherein said gaseous process stream comprises oxygen. 0

8. A method of generating a gaseous process stream and providing it through an outlet at a controllable velocity and momentum, comprising

(A) providing a chamber that has a fuel inlet connected to a source of fuel, an oxidant inlet that is connected to a source of oxidant, a process material inlet that is connected to a source of process material which provides said process material into S said chamber at a first temperature, and an outlet through which gas can pass from the chamber,

(C) determining the temperature that the gaseous process stream is to have0 as it passes from the chamber through said outlet in order to have said velocity and momentum,

(D) determining the amounts of fuel and oxidant that must be combusted in the chamber to generate sufficient heat of combustion to raise the temperature of said process material from said first temperature to the temperature determined in step (C),5 (£) feeding the amounts of fuel and oxidant determined in step (D) into said chamber, feeding said process material into said chamber, and combusting said fuel with said oxidant and with combustible components, if any, in said process material to form said gaseous process stream, and passing said gaseous process stream through said outlet, and (F) controlling the velocity and the momentum of said gaseous process stream as it passes through said outlet by controlling the amounts of fuel and oxidant fed into said chamber in step (E) and combusted therein.

9. A method according to claim 8 wherein the process material comprises gas.

10. A method according to claim 8 wherein the process material comprises S liquid.

1 1. A method according to claim 8 wherein the process material comprises solid. 0

12. A method according to claim 8 wherein the process material comprises combustible matter.

13. A method according to claim 8 wherein the process material comprises oxygen. 5

14. A method according to claim 8 wherein said gaseous process stream comprises oxygen.

15. A method of operating an apparatus, comprising 0 (A) providing apparatus that comprises a device which emits a first gaseous process stream into a workspace or toward a workpiece,

(C) providing a chamber that has a fuel inlet connected to a source of fuel,5 an oxidant inlet that is connected to a source of oxidant, a process material inlet that is connected to a source of process material, and an outlet through which a second gaseous process stream can pass from the chamber into said workspace or toward said workpiece;

(O) feeding fuel and oxidant into said chamber, feeding said process material into said chamber, and combusting said fuel and oxidant with combustible components, if any, in said process material to form said second gaseous process stream, and passing said second gaseous process stream through said outlet into said workspace or toward said workpiece, wherein said second process stream intersects said first gaseous process stream.

16. A method according to claim 15 wherein the process material comprises gas.

17. A method according to claim IS wherein the process material comprises liquid.

18. A method according to claim IS wherein the process material comprises solid.

19. A method according to claim 15 wherein the process material comprises combustible matter.

20. A method according to claim 15 wherein the process material comprises oxygen.

21. A method according to claim 15 wherein said gaseous process stream comprises oxygen.

22. A method according to claim 15 wherein said gaseous process stream passes through said outlet into a workspace.

23. A method according to claim 22 wherein said workspace is a process heater.

24. A method according to claim 15 wherein said gaseous process stream passes through said outlet toward a workpiece.

25. A method according to claim 24 wherein said workpiece is a slab of metal.

26. A method according to claim 24 wherein said workpiece is a body of S liquid.

27. A method of modifying an apparatus, comprising

(A) providing apparatus that comprises a device which emits a first gaseous process stream into a workspace or toward a workpiece; 0 (B) adding to said apparatus a chamber that has a fuel inlet connected to a source of fuel, an oxidant inlet that is connected to a source of oxidant, a process material inlet that is connected to a source of process material, and an outlet through which a second gaseous process stream can pass from the chamber into said workspace or toward said workpiece; 5 (C) feeding fuel and oxidant into said chamber, feeding said process material into said chamber, and combusting said fuel with said oxidant and with combustible components, if any, in said process material to form said second gaseous process stream, and passing said second gaseous process stream through said outlet into said workspace or toward said workpiece. 0

28. A method according to claim 27 wherein the process material comprises gas.

29. A method according to claim 27 wherein the process material comprises liquid.

30. A method according to claim 27 wherein the process material comprises solid.

31. A method according to claim 27 wherein the process material comprises combustible matter.

32. A method according to claim 27 wherein the process material comprises oxygen.

33. A method according to claim 27 wherein said gaseous process stream comprises oxygen.

34. A method according to claim 27 wherein said gaseous process stream passes through said outlet into a workspace.

35. A method according to claim 34 wherein said workspace is a process heater.

36. A method according to claim 27 wherein said gaseous process stream passes through said outlet toward a workpiece.

37. A method according to claim 36 wherein said workpiece is a slab of metal.

38. A method according to claim 37 wherein said workpiece is a body of liquid.

39. A method of modifying an apparatus, comprising

(A) providing apparatus that comprises a device which emits a first gaseous process stream into a workspace or toward a workpiece; (B) adding to said apparatus a chamber that has a fuel inlet connected to a source of fuel, an oxidant inlet that is connected to a source of oxidant, a process material inlet that is connected to a source of process material, and an outlet through which a second gaseous process fluid can pass from the chamber into said workspace or toward said workpiece; (C) determining the velocity and momentum that said second process stream is to have as it passes from the chamber through said outlet, (D) determining the temperature that said second process stream is to have as it passes from the chamber through said outlet in order to have said velocity and momentum,

(E) determining the amounts of fuel and oxidant that must be combusted in S the chamber to generate sufficient heat of combustion to raise the temperature of said second process stream to the temperature determined in step (D),

(F) feeding the amounts of fuel and oxidant determined in step (E) into said chamber, feeding said process material into said chamber, and combusting said fuel with said oxidant and with combustible components, if any, in said process 0 material to form said second process stream, and passing said second process stream through said outlet into said workspace or toward said workpiece.

40. A method according to claim 39 wherein the process material comprises gas. 5

41. A method according to claim 39 wherein the process material comprises liquid.

42. A method according to claim 39 wherein the process material comprises0 solid.

43. A method according to claim 39 wherein the process material comprises combustible matter. 5

44. A method according to claim 39 wherein the process material comprises oxygen.

45. A method according to claim 39 wherein said gaseous process stream comprises oxygen.

46. A method according to claim 39 wherein said gaseous process stream passes through said outlet into a workspace.

47. A method according to claim 46 wherein said workspace is a process heater.

S 48. A method according to claim 39 wherein said gaseous process stream passes through said outlet toward a workpiece.

49. A method according to claim 48 wherein said workpiece is a slab of metal. 0

50. A method according to claim 48 wherein said workpiece is a body of liquid.