WO1999029913A1

WO1999029913A1 - Feed injection device and method for control of accretion

Info

Publication number: WO1999029913A1
Application number: PCT/US1998/026471
Authority: WO
Inventors: Bir Kapoor; Mark A. Wilkinson
Original assignee: Quantum Catalytics LLC
Current assignee: Quantum Catalytics LLC
Priority date: 1997-12-11
Filing date: 1998-12-11
Publication date: 1999-06-17
Anticipated expiration: 2000-06-11
Also published as: AU1912199A

Abstract

A feed material is directed through a first tube (38) of a feed injection device (20) embedded within a refractory lining (19) of a molten bath reactor into a mixing zone (56) located between the outlet end (25) of the feed injection device and the molten bath (24). A reactant, such as an oxidant material, is directed into the mixing zone through a second tube (34) of the feed injection device. Optionally, a co-feed material is directed into the mixing zone (56) through a third tube (32) of the feed injection device. In one preferred embodiment, the tubes are concentrically disposed with respect to one another, wherein the first tube is recessed to a distance (d) below the adjacent surface of the molten bath (24) to form a mixing zone (56) within the feed injection device (20). Directing the mixture of materials into the molten bath by controlling the oxidant-to-feed material ratio provides for effective control of the formation of accretion of metal at the tip of the feed injection device from the molten bath at the operating conditions of the feed injection device.

Description

FEED INJECTION DEVICE AND METHOD FOR CONTROL OF ACCRETION

Background of the Invention

Feed injection devices such as lances or tuyeres are commonly used for injecting various feed materials, such as organic compositions, into a molten bath, such as a molten metal bath or molten salt bath, Such devices are particularly useful for submerged injection of waste materials into a molten metal reactor at operating conditions which break down the waste materials into constituent components which can then be formed into useful products. Tuyeres are typically embedded in the refractory wall that lines the reactor interior. In one embodiment, a tuyere is a pipe that extends through the refractory wall to the interior surface of the refractory wall, with the opening of the tuyere being usually located below the surface of the molten bath, either on the side or the bottom of the reactor wall. Lances are feed injection devices mounted to the top of the reactor which extend^" from the reactor headspace into the molten bath to allow for submerged injection of feed, In one embodiment, a mechanical device is provided which allows the lance to be retracted from the bath when feed is not being injected. As the feed material is directed into the molten bath, a portion of the feed material can crack and cause cooling that may lead to accretion formation and deposition of cracked materials can form an accretion of feed and partially decomposed feed at the opening of the feed injection device which can lead to operational problems and diminish the availability of the system to process waste materials,

One attempt to avoid accretion of the feed material about the feed injection inlet is to direct an excessive amount of oxidant, such as oxygen gas, into the feed injection device to burn off the accretion. However, the tip of the device can be exposed to an excessive temperature and oxidation, thereby causing the tip to be burned off, along with a portion of the surrounding refractory lining.

Therefore, a need exists for a new apparatus and method for eliminating or minimizing the problems described above.

Summary of the Invention The present invention relates to the submerged injection of a feed material and a reactant, such as an oxidant, into a molten metal bath. More particularly, the present invention relates to a feed injection device and method for the submerged injection of waste material into a molten metal bath in a molten metal reactor to provide effective control of the product quality, typically the quality of the off gas product formed, or of the heat balance at the tip of the feed injection device, or both, Adjusting the heat balance allows an accretion of metal forming at the feed and reacant passages of the feed injection device to be controlled, while avoiding excessive burn back of the tip of the injection device. The method of one embodiment of the invention includes directing α feed material through a first tube of a feed injection device embedded within a refractory lining of a molten metal reactor into a mixing zone located between the outlet end of the feed injection device and the molten metal bath. A reactant, such as an oxidant material, is directed into the mixing zone through a second tube of the feed injection device, Optionally, a co-feed material is directed into the mixing zone through a third tube of the mixing zone, In one preferred embodiment, the tubes are concentrically disposed with respect to one another, wherein the first tube is recessed to a distance below the adjacent surface of the molten metal bath to form a mixing zone within the feed injection device, Mixing the feed material and the reactant within the mixing zone forms a mixture that is evenly distributed across the outlet of the feed injection device, Directing the mixture of materials into the molten metal bath by controlling the oxidant-to-feed material ratio^" provides the ability for effectively controlling the formation of accretion of metal at the tip of the feed injection device from the molten metal at the operating conditions of the feed injection device.

This invention provides several advantages, One advantage is that the feed injection device provides effective control over accretions at the outlet end of the injection device and can operate for extended periods of operation, Another advantage is that the feed tube is recessed sufficiently from the extreme thermal conditions of the molten metal bath to form a mixing zone within the device which allows thorough mixing of the feed material with other compositions within the passage, namely an oxidant and in some cases co-feeds, such as natural gas, water (steam) or propane, In addition to substantial reduction of the growth of accretions, the formation of a pre-injection mixing zone within the feed injection device permits several other advantages in processing waste materials, For example, the heat balance at the outlet of the feed injection device proximate to the molten metal bath, which is a strong function of the chemical composition of the feed material, can be adjusted to avoid excessive burn back of the feed injection device and the surrounding refractory. Since waste materials can vary from highly endothermic compounds, such as methanol compounds, to highly exothermic compounds, such as chlorinated organic compounds, the present invention affords flexibility in being able to allow injection f r extended operating periods with either class of compound by simple adjustments to reactor operating conditions. In the case of an endothermic feed, an oxidant may be mixed with the feed or a co-feed material in the pre-injection mixing zone to produce a desired chemical reaction with the corresponding heat of reaction being controlled by varying the flow of reactants (i.e. feeds, oxidant and co-feeds when applicable) so that the feed injection device may be used to melt any αccretion or other deposit formed on or in the vicinity of the feed injection device, Conversely, for an exothermic feed, reactants (including co- feeds) and their flow rates can be correspondingly varied in a manner such that when they are mixed in the mixing zone the rate of burn back of the tip of the feed injection device and the surrounding refractory lining can be effectively controlled. Other specific advantages include the ability to reduce problems associated with injection of oxidants into molten nickel baths, such as the generation of nickel oxide accretions, by pre-mixing carbon-containing feeds with an oxidant to provide a carbon source to reduce the nickel oxides to elemental nickel. Also, an oxygen- containing compound pre-mixed with the waste feed material promotes a subsequent oxidation reaction which reduces the amount of dust generated during processing, Pre-mixing feed and other reactants also avoids pyrolytic cracking which produces deposits on the walls of the feed injection device that may ultimately plug the passageways, The net effect of pre-injection mixing within the device is to increase the effective throughput and on stream factor of the feed injection device by minimizing accretion and plugging problems as well as by optimizing process chemistry which results in optimal production of desired product(s), Brief Description of the Drawings

Figure 1 is a cut-away side elevational view of one embodiment of the apparatus of the present invention in a molten metal bath reactor,

Figure 1 A is a cut-away side elevational view of the submerged feed injection device shown in Figure 1 ,

Figure 2 is a cut-away side elevational view of a second embodiment of the feed injection device shown in Figure 1 ,

Figure 3 is a cut-away side elevational view of a third embodiment of the feed injection device shown in Figure 1 .

Figure 4 is a cut-away side elevational view of a fourth embodiment of the feed injection device shown in Figure 1 ,

Figure 5 is a cut-away side elevational view of a fifth embodiment of the feed injection device shown in Figure 1 ,

Figure 6 is a graph showing the pressure response during injection of feed and reactant materials of the feed injection device shown in Figure 2,

Detailed Description of the Invention

The features and other details of the apparatus and method of the invention will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. The same numerαl present in different figures represents the same item. All parts and percentages are by weight unless otherwise specified. It will be understood that the particular embodiments of the invention are shown by way of illustration and not as limitations of the invention, The principle features of this invention can be employed in various embodiments without departing from the scope of the invention. For example, the invention is described herein in the context of submerged injection into a molten metal bath in a refractory-lined reactor through bottom injection by means of a tuyere. However, other feed injection devices, such as lances, can be used and other locations for submerged injection, such as through the side walls, are possible.

The present invention relates generally to a method for the submerged injection of waste material into a molten metal contained in a molten metal reactor wherein the waste undergoes a chemical change within the reactor to produce desired product(s), A process and apparatus for dissociating waste in molten baths are disclosed in U.S. Patents 4,574,714 and 4,602,574, issued to Bach/Nagel. The method and apparatus described by these patents can destroy polychlorinated biphenyls and other organic wastes, optionally together with inorganic waste. Both U.S. Patents 4,574,714 and 4,602,574 are hereby incorporated by reference in their entirety. Another apparatus and method for dissociating waste in a molten metal bath and for forming as an output of the reactor desired gaseous, vitreous and metal products from the waste are disclosed in U.S. Patent 5,301 ,620, issued to Nagel et al., the teachings of which are hereby incorporated by reference in their entirety,

One embodiment of the invention is illustrated in Figure 1 , Therein, system 10 includes reactor 12 for containing a molten bath suitable for dissociating a feed material, Examples of suitable reactors include appropriately modified steelmaking vessels known in the art, such as K-BOP, Q-BOP, argon-oxygen decarbonization furnaces (AOD), BOF, etc, Reactor 12 includes upper portion 14 and lower portion 16, Off-gas outlet 18 extends from upper portion 14 and is suitable for conducting an off-gas composition out of reactor 12, Reactor 12 has metal shell 17 and is lined with refractory lining 19, Refractory lining 19 can be, for example, bricks composed of aluminum oxide (A1₂0₃) magnesium oxide (MgO) , 'silicon dioxide (Si0₂) thorium dioxide (Th0₂), zirconium dioxide (Zr0₂) or other suitable materials, such as a ceramic. The refractory lining can be coated with a gas permeable coating, such as sputtered aluminum oxide,

Tuyere 20 is located at lower portion 16 of reactor 12 and can be a multiple concentric tuyere, in particular, a triple concentric tuyere, Tuyere 20, which is a concentric tuyere, includes feed material tube line 22 for directing a feed material to feed material tube 32 for injection of the feed material through feed material tube outlet 25 to bath inlet 24, Feed material tube outlet 25 is recessed from the surface 21 of refractory lining 19 within tuyere 20. For sake of clarity and economics of space, the degree of recess of the various tubes shown in the drawings is not drawn to scale. For example, in one embodiment, feed material tube outlet 25 is at a distance from the bath inlet 24 in the range of between about five to one hundred times, and preferably between about 5 to 20 times, the internal diameter of tuyere 20. Line 26 extends between feed material tube line 22 and feed material source 28 for conducting feed material from feed material source 28 by pump 30 to feed material tube 22,

Oxidant tube 34 of tuyere 20 is disposed concentrically around feed material tube 32 at bath inlet 24, Feed material tube outlet 25 is sufficiently recessed within oxidant tube 34 to allow feed material and oxidant to mix thoroughly within tuyere 20 before entering the molten metal bath, thereby effectively controlling the formation of accretion of metal on the outlet end of feed tube 32. Line 35 extends between ^" oxidant source 36 and oxidant tube 34 for conducting a suitable oxidant through oxidant tube 34 to oxidant inlet 37, Oxidant can be, for example, oxygen gas or some other gas which can oxidize a portion of the waste to form a product, such as steam or carbon dioxide,

Shroud gas tube 38 of tuyere 20 is disposed concentrically around oxidant tube 34 at bath inlet 24, Line 40 extends between shroud gas tube 38 and shroud gas source 42 for conducting a suitable shroud gαs through shroud gas inlet 39, which is the concentric opening between oxidant tube 34 and shroud gas tube 38, at bath inlet 24, Shroud gas can be, for example, an inert gas, such as argon or nitrogen, or a mixture of inert gas and a coolant, wherein the coolant can be a hydrocarbon, such as propane or methane, carbon dioxide or water.

Bottom tapping spout 44 extends from lower portion 16 of reactor 12 and is suitable for removal of metal from reactor 12. Induction coil 46 is located at lower portion 16 for heating molten metal bath 48 in reactor 12. It is to be understood, alternatively, reactor 12 can be heated by other suitable means, such as by an oxyfuel burner, electric arc, etc.

Molten metal bath 48 is formed within reactor 12. Molten metal bath 48 can include at least one metal or molten salt or metal oxides thereof or mattes, Examples of suitable metals include copper, iron, nickel, zinc, etc. Examples of suitable salts include potassium chloride, sodium chloride, etc, Examples of suitable mattes include iron sulfide, nickel sulfide, copper sulfide, etc. Molten bath 48 can also include more than one metal. For example, molten bath 48 can include a solution of immiscible metals or miscible metals, such as iron and nickel. In one embodiment, molten bath 48 can be formed substantially of elemental metal, Alternatively, molten bath 48 can be formed substantially of metal salts. Molten bath 48 is formed by at least partially filling reactor 12 with a suitable metal or metal salt. In another embodiment, molten bath 48 is formed of immiscible metals, These immiscible metals can include first metal 50, such as iron, and second metal 52, such as copper, Molten metal 48 is then heated by a suitable means, such as induction coil 46 or oxyfuel burner, not shown.

Suitable operating conditions of system 10 include, for example, a temperature which is sufficient to at least partially convert carbonaceous feed by dissociation to elemental carbon and other elemental constituents. Generally, a temperature in the range of between about 1 ,300 and 1,700°C is suitable, Additionally, reactor 12 can be a pressurizeable vessel capable of operating under positive or negative (vacuum) conditions. In one embodiment, reactor 12 is a closed, pressure-tight vessel that is operated at a pressure range of about 0-10 bars,

Vitreous layer 54 is formed on molten bath 48. Vitreous layer 54 is substantially immiscible with molten bath 48, Vitreous layer 54 can have a lower thermal conductivity than that of molten bath 48, Radiant heat loss from molten bath 48 can thereby be reduced to significantly below the radiant heat loss from molten bath 48 where no vitreous layer is present.

Typically, vitreous layer 54 can include at least one metal oxide, Vitreous layer 54 can contain a suitable compound for scrubbing halogens, such as chlorine or fluorine, to prevent formation of hydrogen halide gases, such as hydrogen chloride. In one embodiment, vitreous lαyer 54 comprises α metal oxide having a free energy of oxidation, at the operation conditions of system 10, which is less than that for the oxidation of atomic carbon to carbon monoxide, such as calcium oxide (CaO),

As can be seen in Figure 1 A, a submerged feed inlet for controlling the formation of accretion 58 includes a feed material tube outlet 25 recessed from the surface 21 of refractory lining 19 within tuyere 20. In a preferred embodiment, feed material tube outlet 25 is below refractory surface 21 at a distance (d) in the range of between about five to one hundred times the internal diameter of tuyere 20, which is, in one embodiment, the internal diameter of shroud gas tube 38, Also, feed material tube outlet 25 is preferably parallel with refractory surface 21. In a particularly preferred embodiment, tuyere 20 has an inside diameter of about 0,3 inches (0,76 cm) and feed material tube outlet 25 is about five inches (12,7 cm) below refractory surface 21 . Mixing zone 56 can be formed within tuyere 20 above feed material tube outlet 25 and below surface 21 of refractory lining 19 and below adjacent surface of molten bath 48, and within oxidant tube 34 of tuyere 20. Mixing zone 56 allows thorough mixing of the feed material and oxidant prior to interaction with the molten metal.

Waste material, in the form of a suitable gaseous, liquid or solid feed, is directed into mixing zone 56, from feed material source 28 through line 26 and feed material tube line 22 to feed material tube 32 in tuyere 20 towαrds molten bath 48, Waste material enters mixing zone 56 at feed material outlet 25. A wide variety of waste materials can be used which includes organic waste. An example of a suitable organic waste is a hydrogen-containing carbonaceous material, such as oil or a waste which include organic compounds containing nitrogen, sulfur, oxygen, etc, It is to be understood that the organic waste can include inorganic compounds, In addition to carbon and hydrogen, the organic waste can include other constituents, such as halogens, metals, etc. Oxygen gas or another oxidant is directed from oxidant source 36 through line 35 to oxidant tube 34 into mixing zone 56, A suitable shroud gas, such as hydrocarbon or inert gas, is directed from shroud gas source 42 through line 40 to shroud gas tube 38,

As the waste feed material and oxidant are directed into mixing zone 56, the feed material and oxidant sufficiently mix within mixing zone 56 before injection into molten metal bath 48 to cause even distribution of the feed material and oxidant across the outlet of tuyere 20, Even distribution of the feed material and reactant can be the result of shear force caused by contact between the feed and reactant, Pre- injection mixing of feed (waste) with oxidant within the injection device has several advantages. First, in waste treatment processes using molten bath reactors the hazards of explosion are greatly minimized when mixing occurs within the injection device as opposed to other locations further upstreαm of the molten bath, Mixing controls the heat of reaction released due to bath material oxidation by lowering the oxygen partial pressure in the immediate vicinity of tuyere 20, This allows the heat balance at the outlet end of tuyere 20 to be adjusted to effectively control the solidification of molten metal on or in the vicinity of the tip of the tuyere 20, a phenomenon more commonly referred to as accretion formation. Additionally, lower partial pressure of oxygen minimizes the risk of metal oxides formation, in general, high local concentration of metal oxides (e.g. Cu₂0, FeO) in the vicinity of tuyere 20 promotes chemical refractory erosion thereby reducing the life of the tuyere, in other cases, formation of higher melting point metal oxides (e.g. NiO, Fe₂0₃) in the vicinity of tuyere 20 may lead to the formation of higher melting point accretions and partial plugging of tuyere 20, This situation can be alleviated by adjusting the flow rates of the feed and co-feed material and the oxidant accordingly to provide a carbon source for reducing the metal oxides to a lower melting point composition. Alternatively, flow rate adjustment can also raise the heat of reaction at the outlet end of the injection device to melt any formed accretion. In this event, care must be taken to avoid excessive reactive heat to minimize the rate of burn back of tuyere 20 and surrounding refractory lining 19. Furthermore, such pre- mixing is also expected to suppress carbonaceous dust formation in reactor 12 by minimizing pyroiysis and by providing mixing of oxygen with feed prior to bubble breakup and exposure to the high temperature environment of molten bath 48. In some cases, e.g. in processing highly chlorinated wastes, where tighter control on bath chemistry is desired to suppress metal chloride dust formation by controlling molar H/CI ratio in the gas phase, it may be desirable to direct a co-feed into tuyere 20, For example, mixing of a hydrogen-containing compound as a co-feed with the chlorinated waste feed in mixing zone 56 provides effective control of off-gas chemistry and minimizes the dependence of off-gas chemistry on bath mixing patterns,

The injection of pre-mixed feed material and oxidant, and in some cases co-feed material, in a controlled manner also can impact the formation of desired product or products, In one embodiment involving the processing of chlorinated organic waste, it is desired to produce a gaseous stream of hydrogen, carbon monoxide, and hydrochloric acid, It is also desirable to control the ratio of various gases in the off gas to maximize the healing value of these gases. Pre-mixing and controlling the flow rates of the feed, oxidant and co-feeds, such as water (steam), propane or natural gas optimizes the production of desired product(s) by effectively shifting the chemical equilibrium to maximize hydrogen chloride yield,

Mixing zone 56, which is within tuyere 20, can maintain a reaction zone 60 at bath inlet 24, if the flow rates of the waste feed mαteriαi and oxidant are maintained at a fully expanded Mach number in the range of about 0.2 to 1.2 to avoid burning back the tubes of tuyere 20 and the surrounding refractory lining 19 due to the heat of reaction, The recession of material feed tube 32 is believed to assist in minimizing the formation of oxides at bath inlet 24 due to a relatively low oxygen partial pressure in the vicinity of bath inlet 24. This modification eliminates the need for oxygen injection through feed material tube 32 to open tuyere 20 during the start up of feed injection into molten bath 48 within reactor 12.

Tuyere 20 is formed of materials suitable for use in multiconcentric tuyeres, Examples of suitable materials include copper, tungsten, stainless steel, alumina and graphite.

In Figure 2, a second embodiment of the invention is shown which is particularly useful in creating an exothermic reaction zone 60 to control the formation of accretion at the tip of tuyere 20, In this ^' embodiment, mixing oxygen with a co-feed of natural gas in mixing zone 56, and in the presence of high molten bath temperature, creates a flame at the tip of tuyere 20, which in turn can be controlled to provide removal, or even prevent formation, of high melting point accretions. This embodiment is also useful in situations where severe accretion formation occurs during process start up due to extreme change in thermal environment, as for example during pre-heating and melting of metal chαrge prior to injection, In this instance, oxidant tube 34 is recessed to about the same depth as feed material tube 32 and both tubes are recessed from the surface of refractory lining 19 to a distance in the range of between about five to one hundred times the internal diameter of the shroud tube 38, In a preferred embodiment, oxidant tube 34 is recessed from the surface of the refractory lining 19 to a distance in the range of between about five to twenty times the internal diameter of shroud tube 38, Mixing zone 56 allows thorough mixing of the feed material, oxidant and shroud gas prior to contact with the molten metal. Reaction zone 60 is formed in a region above bath inlet 24 where the mixture of feed material, oxidant and shroud gas reacts in the presence of molten bath 48 to form their elemental constituents from which reaction products are formed, for example, hydrogen gas (H₂), carbon monoxide, carbon dioxide, and hydrogen chloride (HCI).

Figure 3 shows a third embodiment in which oxidant tube 34 is recessed within tuyere 20 to a depth intermediate that of feed tube 32 and shroud tube 38. This embodiment is particularly useful during the start of waste feed injection to provide accretion control as the functionality and advantages of both the Figure 1A and Figure 2 embodiments are combined in a single device,

In Figure 4, a fourth embodiment of the invention is shown which is particularly useful to control burn back of tuyere 20 and refrαctory lining 19, Feed material tube inlet 25, oxidant inlet 37 and shroud gas inlet 39 are disposed individually and nonconcentrically at the base of tuyere 20, Feed material, oxidant and shroud gas can be directed through feed material tube 32, oxidant tube 34 and shroud gas tube 38, respectively, into mixing zone 56 of tuyere 20. This embodiment is similar in functionality to the Figure 1 A embodiment described above except that this particular embodiment provides added flexibility by allowing the injection of multiple feeds simultaneously. Additionally, the waste feed acceptability criteria are widened by allowing much larger solids to be processed through tuyere 20, This embodiment also provides flexibility by providing the ability to change feed inlets in case the primary feed outlet tube becomes plugged, Furthermore, simultaneous processing of more than one type of waste feed can be accommodated without the risk of any undesired chemical reaction occurring in the event that the feeds are reactive with one another.

Figure 5, shows a fifth embodiment of the invention which is particularly useful to control burn back when highly exothermic waste materials are injected into reactor 12, This embodiment is similar to the one shown in Figure 4 except in this case a coolant jacket 62 has been included proximate to tuyere 20 to provide cooling in the vicinity of tuyere 20, Jacket 62 can be employed to circulate a suitable coolant, such as liquid water, water mist, steam or natural gas around tuyere 20 and thereby maintain a suitably cool temperature at the tuyere, Such cooling maintains a desired temperature range within the vicinity of tuyere 20 and surrounding refractory lining 19. The provision of a cooling source can also be used to freeze bath material around the inner walls of mixing zone 56 to provide a protective layer,

In the embodiments described above, the method for submerged injection of a feed (waste) material utilizing the pre-mixing of feed and oxidant (and optionally co-feeds) has been shown to be important for optimizing the quality of desired product(s) produced, This optimization may be accomplished through effective control of the formation of an accretion of metal to enhance system availability (up-time) or by using pre-mixing to control process chemistry. For purposes herein, both of the foregoing aspects of control are to be encompassed as contributing to product optimization. The following example illustrates an application of the method of the present invention. Example

A stainless steel tuyere constructed in accordance with the embodiment of Figure 2, in which the inner two tubes were initially recessed from the outermost tube by about 7 times the internal diameter of the outermost tube, was inserted in the bottom refractory block of a molten bath reactor. The reactor was charged with nickel metal which was brought to its molten state by activation of an induction furnace. A chlorinαted waste stream surrogate containing a fifty-fifty mixture by weight of methylene chloride and toluene to be treated by the reactor was injected beneath the surface of the molten bath of the reactor as feed material through the center most tube of the tuyere, An oxidant comprised of a mixture of oxygen and nitrogen was concurrently injected through the oxidant tube disposed concentrically about the central feed tube. A mixture of natural gas and nitrogen, used as a coolant, was fed through the outermost tube of the tuyere, A series of injection runs v/as conducted over several hours with the flow rates of feed, oxygen, natural gas and nitrogen being 32lb/hr, 21lb/hr, 3,6 Ib/hr and33.5lb/hr, respectively. The back pressure of each tube was constantly monitored during the injection runs,

Figure ό is a graph of the pressure response of the feed injection runs described above, For sake of clarity, only the pressure response of the feed passage (represented by the thicker line 70) and of the coolant passage (represented by the thinner line 72) are shown. The data corresponding to the pressure response of the oxidant passage were also recorded and were found to closely track the responses of the other two passages. Figure 6 demonstrates that once steady-state injection was achieved, the onset of which is indicated by reference numeral 80, the back pressure remained constant for over 3 hours, During this time period, the extent of bottom refractory block wear (and consequent burn back of the outer coolant tube), which was also monitored by means of appropriately positioned thermocouples, and the correlation between various back pressures indicated the existence of a mixing zone within the tuyere,

The spike in the back pressure of the feed passage, represented by reference numeral 82, corresponds to the point of bottom refractory block wear at which outer coolant tube and the other two inner concentric tubes are all the same height, that is to say the mixing zone within the tuyere is no longer present, As shown in the region to the right to pressure spike 82, the pressure response of the two passages no longer track one another and indicate a tuyere configuration and operational behavior similar to a conventional (flush-type) tuyere design,

Comparing injection throughput, as indicated by the back pressure measurements of Figure 6, shows that after losing the mixing zone and the recessed section of the tuyere it became difficult to operate and maintain a steady state injection condition due to the poor accretion control capability of the conventional, flush-type tuyere design, This ^" example also clearly indicates the superior operating performance when the mixing zone is present as contrasted with results obtained in the absence of a mixing zone. Equivαlents

Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to specific embodiments of the invention described specifically herein, Such equivalents are intended to be encompassed in the scope of the following claims.

Claims

1 . A method for producing α desired product by the submerged injection of α feed material into a molten metal bath reactor through a feed injection device having an outlet end adjacent the molten metal bath, said injection device being embedded within a refractory lining of the reactor comprising the steps of: a) providing α first tube for directing the feed material to a mixing zone located between the outlet end and the molten metal bath; b) providing a second tube for directing an oxidant to the mixing zone; c) mixing the feed material and the oxidant within the mixing zone to form a mixture thereof; d) directing the mixture into the molten metal bath whereby the mixture interacts with the metal bath to produce the desired product; and e) controlling the oxidant-to-feed material ratio to optimize production of the desired product,

2, The method of Claim 1 wherein the feed material reacts with the oxidant to produce a chemical reaction and the heat of reaction is controlled to adjust the heat balance at the outlet end of the feed injection device proximate the molten bath, whereby formation of accretion of metal at the outlet end of the feed injection device is effectively controlled.

3. The method of Claim 1 wherein the feed material reacts with the oxidant and the stoichiometry of the reaction is controlled to produce the desired product.

4. The method of Claim 2 wherein the oxidant-1o-feed material ratio is adjusted by controlling the flow rate of the feed material and the oxidant,

5. The method of Claim 3 wherein the oxidant-to-feed material ratio is adjusted by controlling the flow rate of the feed material and the oxidant.

6. The method of Claim 2 wherein the flow rates are controlled to produce the chemical reaction proximate the outlet end.

7. The method of Claim 6 wherein the heat of reaction is controlled to minimize the rate of burn back of the outlet end of the feed injection device,

8. The method of Claim 1 including the step of providing a third tube for directing a co-feed to the mixing zone, wherein the co-feed interacts with the feed material and with the molten metal bath.

9. The method of claim 8 wherein the feed material reacts with the oxidant and the co-feed to produce a chemical reaction and the heαt of reaction is controlled to adjust the heat balance at the outlet end of the feed injection device proximate the molten bath, whereby formation of accretion of metal at the outlet end of the feed injection device is effectively controlled,

10. The method of Claim 9 including the step of controlling the feed to-co-feed material ratio.

11. The method of Claim 10 wherein the flow rates of the feed material, oxidant and the co-feed are controlled.

12. The method of Claim 1 1 wherein the heat of reaction is controlled to minimize the rate of burn back of the outlet end of the feed injection device,

13. The method of Claim 8 wherein the feed and co-feed material react with the oxidant and the stoichiometry of the reaction is controlled to produce the desired product,

14. The method of Claim 8 wherein the feed material is a chlorinated composition and the co-feed is a hydrogen-containing composition and the desired product is a mixture of carbon monoxide, hydrogen and hydrogen chloride.

15. The method of Claim 14 wherein the hydrogen-containing composition is water.

16. The method of Claim 14 wherein the hydrogen-containing composition is natural gas,

17. The method of Claim 8 wherein each of the first, second and third tubes are concentrically disposed with respect to each other, with the first tube being located within the second tube and the second tube being located within the third tube and wherein the first tube is recessed from each of the second and third tubes at a distance of between 5 to

100 times the internal diameter of the third tube.

18. The method of Claim 17 wherein the first tube is recessed from each of the second and third tubes at a distance of between 5 to 20 times the internal diameter of the third tube,

19. The method of Claim 17 wherein the second tube is recessed from the third tube to about the same distance as the first tube.

20. The method of Claim 17 wherein the second tube is recessed from the third tube to a distance intermediate the distance the first tube is recessed from the third tube,

21. The method of Claim 1 wherein the oxidant is selected from a group consisting of oxygen gas, air, steam and carbon dioxide or mixtures thereof.

22. The method of Claim 8 wherein the feed material is an organic waste selected from a group consisting of oil, organic compounds containing chlorine, nitrogen, sulfur or oxygen, inorganic compounds, and organic compounds containing metals or mixtures thereof.

23. The method of Claim 8 wherein the mixing zone comprises a tubular section embedded within the refractory lining and having a first end adjacent the molten bath and a second end for receiving each of the first, second and third tubes, each of said tubes being non- concentrically positioned with respect to one another within the refractory lining, whereby the feed material, the co-feed and the oxidant can mix within the tubular section prior to interacting with the molten bath.

24. The method of Claim 23 wherein the tubular section includes a fluid-cooled jacket.

25. The method of Claim 24 wherein the fluid of the fluid-cooled jacked includes water, gas or mixtures thereof.

26. The method of Claim 23 wherein the oxidant is selected from a group consisting of oxygen gas, air, steam and carbon dioxide or mixtures thereof,

27. The method of Claim 26 wherein the feed material is an organic waste selected from a group consisting of oil, organic compounds containing chlorine, nitrogen, sulfur or oxygen, inorganic compounds, and organic compounds containing metals or mixtures thereof.

28. The method of Claim 27 wherein the co-feed is a hydrogen- containing composition selected from a group consisting of hydrogen gas, water and natural gas or mixtures thereof,

29. A method for submerged injection of α feed material into a molten bath reactor through a feed injection device having an outlet end adjacent the molten bath, said injection device being embedded within a refractory lining of the reactor, comprising the steps of; a) providing a first tube for directing the feed material to a mixing zone located between an outlet end of the first tube and the molten bath; b) providing a second tube for directing a reactant to the mixing zone; c) mixing the feed material and the reactant within the mixing zone to form a mixture that is evenly distributed across the outlet end of the feed injection device; and d) directing the mixture into the molten bath whereby the mixture interacts with the molten bath.

30. The method of Claim 29 wherein the reactant is an oxidant.

31. The method of Claim 30 wherein the oxidant-to-feed material ratio is controlled to optimize production of a desired product,

32. The method of Claim 30 wherein the feed material reacts with the oxidant to produce a chemical reaction and the heat of reaction is controlled to adjust the heat balance at the outlet end of the feed injection device proximate the molten bath, whereby formation of αccretion of metal at the outlet end of the feed injection device is effectively controlled.

33. The method of Claim 30 wherein the feed material reacts with the oxidant and the stoichiometry of the reaction is controlled to produce the desired product.

34. The method of Claim 31 wherein the oxidant-to-feed material ratio is adjusted by controlling the flow rate of the feed material and the oxidant.

35. The method of Claim 32 wherein the heat of reaction is controlled to minimize the rate of burn back of the outlet end of the feed injection device.

36. The method of Claim 30 including the step of providing a third tube for directing a co-feed to the mixing zone, wherein the co-feed interacts with the feed material and with the molten bath.

37. The method of claim 36 wherein the feed material reacts ^"with the oxidant and the co-feed to produce a chemical reaction and the heat of reaction is controlled to adjust the heat balance at the outlet end of the feed injection device proximate the molten bath, whereby formation of accretion of metal at the outlet end of the feed injection device is effectively controlled.

38. The method of Claim 37 wherein the flow rates of the feed material, oxidant and the co-feed are controlled.

39. The method of Claim 36 wherein the feed material is a chlorinated composition and the co-feed is a hydrogen-containing composition and the desired product is a mixture of carbon monoxide, hydrogen and hydrogen chloride.

40. The method of Claim 39 wherein the hydrogen-containing composition is water.

41. The method of Claim 39 wherein the hydrogen-containing composition is natural gas.

42. The method of Claim 36 wherein each of the first, second and third tubes are concentrically disposed with respect to each other, with the first tube being located within the second tube and the second tube being located within the third tube and wherein the first tube is recessed from each of the second and third tubes at a distance of between 5 to

100 times the internal diameter of the third tube.

43. The method of Claim 42 wherein the first tube is recessed ^"from each of the second and third tubes at a distance of between 5 to 20 times the internal diameter of the third tube.

44. The method of Claim 42 wherein the second tube is recessed from the third tube to about the same distance as the first tube.

45. The method of Claim 42 wherein the second tube is recessed from the third tube to a distance intermediate the distance the first tube is recessed from the third tube.

46. The method of Claim 36 wherein the mixing zone comprises a tubular section embedded within the refractory lining and having a first end adjacent the molten bath and a second end for receiving each of the first, second and third tubes, each of said tubes being non- concentrically positioned with respect to one another within the refractory lining, whereby the feed material, the co-feed and the oxidant can mix within the tubular section prior to interacting with the molten bath.

47. The method of Claim 46 wherein the tubular section includes a fluid-cooled jacket.

48. The method of Claim 46 wherein the fluid of the fluid-cooled jacked includes water, gas or mixtures thereof.

49. The method of Claim 46 wherein the feed material is an organic waste selected from a group consisting of oil, organic compounds containing chlorine, nitrogen, sulfur or oxygen, inorganic compounds, and organic compounds containing metals or mixtures thereof.

50. The method of Claim 49 wherein the co-feed is a hydrogen- containing composition selected from a group consisting of hydrogen gas, water and natural gas or mixtures thereof.