MXPA00000070A - Fuel injector nozzle with protective refractory insert - Google Patents

Abstract

The fuel injector nozzle (10) for a gasifier includes a protective recfractory sheath (70) that is flush mounted at a downstream end proximate the nozzle outlet portion (40). The refractory insert (72) is of annular form to surround the nozzle outlet. The annular refractory member can be a one-piece structure or a multi-segment structure. Whether the annular refractory member is a one-piece structure or a multi-segment structure, it is recessed in a downstream end surface of the fuel injector nozzle and retained in the recessby locating pins (110) or by thread-like engagement between a projection (144) and a groove (172) that are provided on complementary inter-engaging surfaces of the recess and refractory member. The enduring presence of the annular refractory member prolongs the service life of the fuel injector by protecting the vulnerable surface areas at the downstream end of the fuel injector nozzle that are close to a hot and corrosive reaction zone within the gasifier.

Description

FUEL INJECTOR NOZZLE WITH REFRACTORY PROTECTIVE INSERT FIELD OF THE INVENTION This invention is directed to fuel injection nozzles for partial oxidation gasifiers, and more particularly to a new fuel injector nozzle that has a refractory protective insert in the outlet orifice, to resist thermal and thermal deterioration. of the fuel injection nozzle in the exit hole. STATE OF THE ART The processing of carbonaceous fuels, such as coal, gas and oil, to produce gaseous mixtures of hydrogen and carbon monoxide, such as coal gas, synthesis gas, reducing gas or fuel gas, it is generally carried out in a high temperature environment of a partial oxidation gasifier, such as that shown in US Pat. 2,809,104. Partial oxidation gasifiers typically include annular type fuel injection nozzles, as shown, for example, in U.S. Pat. 4,443,230 of Stellaccio (4-ring fuel injection nozzle), and in U.S. Pat. 4,491,456 to Schlinqer (5-ring fuel injection nozzle). The fuel injector nozzle type ring, is used to introduce pumpable slurries of carbonaceous fuels in a reaction chamber of the gasifier, along with gases containing oxygen, for partial oxidation. In general, a slurry of water-mineral coal, which includes materials containing sulfur, is fed into the reaction chamber of the gasifier through one or more rings of the fuel injection nozzle. An oxygen-containing gas, which flows through other fuel injectors, encounters the water-mineral-carbon slurry in an inlet of the injection nozzle and self-ignites at typical temperatures of the gasifier's gasifier. approximately 1315 ° C to 1650 ° C (2400 ° F to 3000 ° F). The usual pressures inside the gasifier environment can be in the range of 1 to 300 atmospheres. In the interior of the gasifier environment, gaseous hydrogen sulfide, a well-known corrosive agent with respect to the metal structure of the injector nozzle during the processing of the water-carbon slurry component of the fueled fuel, is generally formed. Liquid slag is also formed as a by-product of the reaction between the water-carbon slurry and the oxygen-containing gas, and such slag also has a corrosive effect on the metallic structure of the fuel injection nozzle. In addition, the high temperature conditions in the reaction zone around the exit hole of the fuel injection nozzle due to self-ignition of fuel components fed in this area, can cause hot corrosion and induced thermal fatigue that crack the exit hole. The exit orifice of the fuel injector nozzle generally defines the position of the highest thermal gradient zone of the gasifier. Due to the corrosive effects of hydrogen sulphide and liquid slag on the fuel injection nozzle, especially at the outlet orifice, as well as hot corrosion and induced thermal fatigue cracking the outlet orifice, the failure or the breakage of the fuel injection nozzle is likely to occur frequently in the exit orifice, due to thermal deterioration and thermo-chemical degradation. Such thermal deterioration and thermo-chemical degradation of the structure of the fuel injection nozzle limit the useful life of the fuel injection nozzle, which must be repaired or replaced subsequently. However, the repair or replacement of a fuel injection nozzle is expensive and has drawbacks, since the operation of the gasifier must be temporarily interrupted during a cooling period before the fuel injector can be removed for replacement or repair. .

Attempts to limit the deterioration of the fuel injection nozzle due to thermal and corrosive agents, include the provision of trunco-conical protectors of thermal and wear-resistant material, such as tungsten and silicon carbide, fixed to the outlet end of the fuel injection nozzle, as shown in US Pat. 4,491,456 by Schlinger. However, the frusto-conical protection shown by Schlinqer is maintained in vertical orientation and can easily slide from the nozzle. In addition, any joining material to ensure Schlinger frusto-conical protection at the exit end of the fuel injection nozzle may be subject to corrosion and joint failure. The failure of the bonding materials can cause the trunco-conical protection to detach from the fuel injection nozzle. Thus, the useful protective life of the Schlinqer trunco-conical protection at the exit end of the fuel injection nozzle can be reduced prematurely due to the failure of the joining agents that fix the frusto-conical protection to the injection nozzle of gas. The fuel injection nozzle is therefore likely to have a reduced service life due to the premature loss of the protective shield provided by the frusto-conical protection. The Canadian application published no. 2,084,035 to Gehardus et. al , shows a burner for the synthesis gas production, in which the end surface is covered with plates of ceramic material held in place by means of a dovetail joint. The dovetail joint results in a non-uniform wall thickness of the dovetail joint hole, and has an undesired area of reduced wall thickness. The area of reduced wall thickness is an area of stress concentration that is vulnerable to cracking and thermal deterioration. The uneven wall thickness in the dovetail joint can also lead to corrosion and accelerated wear. In addition, the dovetail joint forms a narrow support collar for the ceramic inserts. The narrow neck of support is an area of weakening and vulnerability of the plates, for their deterioration or separation of the burner.

It is desirable to provide a fuel injection nozzle with a refractory protective insert, which is securely retained in the fuel injection nozzle outlet, and whose refractory insert replaces the metal in the highest thermal gradient zone of the nozzle fuel injection. It is also desirable to provide a fuel injection nozzle with a refractory protective insert that remains in place under conditions that promote thermal fatigue corrosion aided by heat deterioration and hydrogen sulfide, whereby the resistant presence of the protective insert refractory extends the useful life of the fuel injection nozzle. OBJECTS AND SUMMARY OF THE INVENTION Among the various objects of the invention, one can appreciate the provision of a new fuel injection nozzle that has a thermal and thermo-chemical protection at the exit orifice, a new fuel injection nozzle having a thermal and thermochemical protective insert fixed to the exit orifice with the use of retention means that immobilize the protective insert around the exit orifice, whereby the retention means are not subject to premature deterioration by corrosive agents or by phenomena thermal, and the insert and the retaining means allow freedom for the thermally induced deformation processes that occur during the start-up operation of the gasifier. A further object of the invention is to provide thermal and thermochemical protection around the exit orifice of the fuel injection nozzle at a relatively low cost, using refractory shapes that are locked with the fuel injection nozzle. Another object of the invention is to provide a fuel injector nozzle with a refractory insert that replaces the metal that is likely to be damaged by the reactions of the process. Still another object of the invention is to provide a new method of extending the life of a fuel injection nozzle. Another object of the invention is to provide a fuel injection nozzle with a new refractory protective insert that is mounted flush around the exit orifice of the fuel injection nozzle. Other objects and features of the invention will be apparent in part and will be emphasized in part in what follows. BRIEF DESCRIPTION OF THE INVENTION According to the invention, a refractory annular insert is locked with the fuel injection nozzle at an exit end close to the outlet end portion of the nozzle. A recess formed in the outlet end of the fuel injection nozzle houses the refractory annular insert. The recess may be trapezoidal in cross section, the term "trapezoidal" being understood to contemplate shapes that are approximately trapezoidal. Other cross-sectional shapes suitable for the recess are within the concept of the invention. The arrangement of the refractory ring insert in the recess includes locking the refractory insert in the fuel injection nozzle by means of immobilization or securing devices that avoid the need for cement or bonding material. The insert does not extend beyond the outlet end of the fuel injection nozzle and is mounted flush on the end surface of the outlet orifice. In one embodiment of the invention, the refractory annular insert is a one-piece member maintained in position in the recess by means of retaining bolts that engage in a formed slot around the circumference of the ring insert. In a second embodiment of the invention, the annular insert is formed as a multi-segment structure. The segments are maintained in their position in a trapezoidal recess by protrusions in the form of protuberances formed in the side walls of the recess, which fit into the peripheral grooves formed in the corresponding side walls of the segments of the annular insert. In another embodiment of the invention, a metal retaining ring is attached to the outlet end of the fuel injection nozzle after the segments of the annular insert have been installed in a mounting recess. The metal retaining ring completes the structure of a trapezoidal recess and also completes the immobilization structure which serves to retain the refractory annular segments within the recess. The multiple segments of the refractory ring insert preferably have stepped end portions which also inter-engage when placed in the recess. The stepped coupling of the segments of the insert limits the passage of slag and corrosive gases, past the segments of the insert, to the underlying metallic structure of the fuel injection nozzle. In all embodiments of the invention, the refractory ring insert protects the exit area of the fuel injection nozzle, at the outlet end portion, in relation to thermal and thermochemical deterioration due to high temperature conditions and corrosion conditions chemistry in a reaction zone of the gasifier. The refractory annular insert thus prolongs the useful life of the fuel injection nozzle and prolongs, correspondingly, the cycle of action of the gasifier. The invention accordingly comprises the constructions and the method described below, the scope of the invention being indicated in the claims. DESCRIPTION OF THE DRAWINGS In the accompanying drawings, Figure 1 is a schematic, simplified, elevational view, shown partially in section, of a multi-ring fuel injection nozzle, with a refractory annular insert incorporating an embodiment of the invention; Figure 2 is an exploded view thereof, showing the refractory annular insert prior to its installation in the exit orifice of the fuel injection nozzle, having omitted here, and in the subsequent Figures, the inner rings of the nozzle fuel injection, for reasons of clarity; Figures 3 and 4 are enlarged, fragmentary views, in section, of the refractory ring insert positioned in the outlet hole for fixing by a bolt; Figure 5 is a bottom sectional view, taken at the exit end thereof, and showing the exit orifice after installation of the refractory annular insert; Figure 6 is a simplified, exploded, perspective view of another embodiment of the invention, in which a multi-segment refractory ring insert is positioned, for installation, in the outlet orifice of a multi-ring injector nozzle gas; Figure 7 is a simplified schematic bottom view thereof, prior to the installation of the multi-segment refractory annular insert in the exit orifice; Figure 8 is a view similar to Figure 7, showing an intermediate position of installation of the segments of the refractory annular insert in the exit orifice of the fuel injection nozzle; Figure 9 is a view similar to Figure 8, showing a final installation position of the refractory ring inserts; Figure 10 is a fragmentary, enlarged sectional view thereof taken on line 10-10 of the Figure 8; Figure 11 is a fragmentary, enlarged sectional view thereof, taken on line 11-11 of Figure 8; Figure 12 is an exploded perspective view of another embodiment of the invention, in which a multi-segment retaining ring is used to immobilize a refractory annular multi-segment insert in the exit orifice of a fuel injection nozzle; Figure 13 is a simplified, schematic lower view thereof, showing an intermediate installation position of the refractory annular multi-segment inserts in the exit orifice of the fuel injection nozzle; Figure 14 is a view similar to Figure 13 showing a finished installation arrangement of the refractory annular multi-segment insert and the multi-segment retaining ring in the exit orifice of the fuel injection nozzle; Figure 15 is a fragmentary, enlarged sectional view thereof, taken on line 15-15 of Figure 12 prior to the installation of the multi-segment retaining ring; Figure 16 is a fragmentary sectional view, enlarged, taken on line 16-16 of Figure 13, and Figure 17 is a fragmentary, enlarged sectional view thereof, taken on line 17-17 of Figure 14. Corresponding reference numbers indicate corresponding parts through the various views of the drawings. DETAILED DESCRIPTION OF THE INVENTION A fuel injector nozzle that incorporates an embodiment of the invention, has been indicated in general with the reference numeral 10 in Figure 1. The fuel injector nozzle 10 is similar to the fuel injection nozzle described in FIG. detail in the US Patent 4,443,230 of Stellacio. The nozzle 10 fuel injection, is of the type used in partial oxidation gasifiers, and has an inlet end 12 and an outlet end 14. The fuel injection nozzle 10, which has cylindrical symmetry about a central axis 16, further includes a central supply flow conduit 20, and concentric annular feed flow conduits 22, 24 and 26 that converge to form an end 40 of exit from the nozzle at the exit end 14. An annular mounting flange 28 attached to the conduit 26 is arranged to be supported on an open end of the reaction chamber of the gasifier (not shown), to allow the outlet end 40 of the nozzle to be suspended in the reaction chamber. The conduits 20, 22, 24 and 26 include respective inlet tubes 30, 32, 34 and 36. The inlet pipe-3O provides a feed flow of gaseous fuel material 42 such as, for example, those of the gas group containing free oxygen, steam, recycled product gas and hydrocarbon gas. The inlet tube 32 provides a slurry 44 in pumped liquid phase of solid carbonaceous fuel, such as, for example, a slag-water slurry. The inlet pipes 34 and 36 provide two separate fuel flows 46 and 48, such that, for example, gas containing free oxygen, mixed with a temperature moderator. The free oxygen containing gas 42, the carbonaceous slurry flow 44, and the free oxygen containing gas flows 46 and 48, from the conduits 20, 22, 24 and 26, are combined at a predetermined distance, beyond the extreme 40 exit from the nozzle at a predetermined position of the reaction chamber of the gasifier (not shown) to form a reaction zone (not shown). The combination of the carbonaceous slurry 44 leaving the conduit 22 with the flows 42, 46 and 48 oxygen containers of the conduits 20, 24 and 26, causes the carbonaceous slurry 44 to be dispersed or atomized, which promotes the reaction of the product. and increases the process of heat induced gasification. As a result, the reaction zone at the exit end 14 of the fuel injection nozzle 10 is characterized by intense heat, with temperatures in the range of 1315 ° C to 1650 ° C (2400 ° F to 3000 ° F). A coaxial shirt 50, annular, cooling by water is provided at the exit end 14 of the fuel injection nozzle 10 to surround the outlet orifice 40. The annular cooling jacket 50 receives the cooling water 52 which arrives through an inlet pipe 54. The cooling water 52 exits 56 from the cooling annular jacket 50 to a cooling coil 58 and exits from the cooling coil 58 by any known suitable drainage or drainage device (not shown). The outlet orifice 40 includes an annular and horizontal surface or outlet end surface 62 at the outlet end 14, which is exposed to the hot reaction zone of the gasifier and is the site of high thermal gradients. The outlet orifice 14 is therefore vulnerable to chemical and heat corrosion, and to cracking by induced thermal fatigue which often leads to operational problems of the fuel injection nozzle 10. To treat the problem of thermal and thermochemical degradation of the fuel injection nozzle 10 in the outlet orifice 40, a refractory protective member 70 is provided on the annular surface 62 in the vicinity of the outlet orifice 40. The refractory protective member 70 includes a one-piece annular insert 72, constructed of a suitable refractory material, which may be of the type ceramic, such as silicon carbide, silicon nitride, or any other known advanced ceramic composite material that is suitable. The annular insert 72 can be molded, machined or formed in any other suitable known manner. With reference to Figures 2 and 3, the insert 72 is trapezoidal in cross section, with a relatively narrow upper base 74 and a relatively wide lower base 76. The terms "trapezoidal" or "trapezoidal shape" as used in the following, are intended to refer to trapezoidal shapes. A radially internal side 78 connects the upper and lower bases 74 and 76 on one side of the trapezoidal shape. A circumferential groove 80 formed in the radially internal side 78 is inclined at an angle that is substantially perpendicular to the radially inner side 78. The insert 72 further includes a radially outer side 82 composed of intersecting lateral portions 84 and 86 connecting the upper and lower bases 74 and 76 of the trapezoidal shape. If desired, the radially outer side 82 can be formed with continuous inclination. With reference to Figures 2 and 4, an annular channel 90 with trapezoidal cross section, has been formed on the metallic annular surface 62 and has a shape and size that are substantially complementary to the trapezoidal shape of the insert 72 in order to house the insert 72. The channel 90 is very close to the outlet orifice 40. The channel 90 includes a top base portion 92 corresponding to the upper base portion 74 of the insert 72, an internal radial surface 94 corresponding to the radially internal surface 78 of the insert 72, a corresponding external radial side 96 with the external radial side 82 of the insert 72, and a channel opening 100 corresponding to the lower base 76 of the insert 72. The external radial side 96 of the channel 90, is composed of intersecting lateral portions 102 and 104 corresponding to the intersecting lateral portions 84 and 86 of the insert 72. A plurality of equally spaced bolt openings 106 are provided in an outlet port inclined wall 108 in the outlet orifice 40. The bolt openings 106 pass through the inner radial surface 94 of the channel 90 and face the annular groove 80 of the refractory insert 72. The bolt openings 106 are substantially at the same angle as the groove 80 relative to the wall surface 78. The outlet orifice wall surface 108 defines a flow path for fluid or mass portions that moves from the outlet orifice 40 of the fuel injection nozzle 10. The refractory insert assembly 72 for the fuel injection nozzle 10 is made by placing the insert 72 in the channel 90, such that the surfaces 74, 78, 84 and 86 of the insert are in substantial surface contact. with-surface with corresponding channel surfaces 92, 94, 102 and 104. If desired, the channel surfaces 92, 94, 102 and 104 can be coated with a suitable known bonding material, such as silicon carbide mortars, Teflon® or other suitable adhesive known for high temperature, prior to installation. of the refractory insert 72. Also, if desired, a coating of silicon dioxide may be applied to the surface 76 of the insert 72, to increase the thermal and thermo-chemical resistance of the annular insert 72.

An immobilization bolt 110 formed from a suitable steel alloy, such as ALLOY 800 manufactured by International Nickel Co., is press-fitted into each of the bolt openings 106, to fit into the groove 80 of the insert 72. refractory, as shown in Figures 3 and 4. Thus, with the arrangement of the refractory insert 72 in the channel 90, the immobilization bolts 110 are led into the groove 80., to immobilize the refractory insert 72 in the channel 90, as shown in Figure 5. Under this arrangement, the base surface 76 of the insert 72 is on an exposed end surface and is substantially coplanar or flush with the surface 62 extreme annular exit of the nozzle 10 fuel injection. The flush mounting arrangement helps to ensure that the fuel injection nozzle 10 with the refractory insert 72 not only resists corrosion and thermal and thermochemical cracking but remains in position under adverse corrosion and high temperature conditions. the interior of the gasifier. In addition, the flush mounting arrangement does not affect the flow of the process even though the fuel injection nozzle is damaged by cracking. Although the dimensions of the channel 90 and the refractory annular insert 72 can be chosen, the size of the channel 90 (which determines the size of the insert 72) can be, for example, from about 6.35 to 19.05 mm (1 / 4 to 3/4 inch) in depth from opening 100 to base 92, approximately 3,17 to 15,87 mm (1/8 to 5/8 inch) wide, and approximately 101 to 152 mm (4 to 6 inches) in diameter on the internal radial surface 94. The wall thickness of the wall 108 (Figure 2) in the channel 90 is about 0.397 to 3.175 mm (1/64 to 1/8 of an inch). The width of the annular groove 80 is approximately 0.397 to 3.175 mm (1/64 to 1/8 of an inch), and the diameter of the immobilization bolt 100 can be approximately 0.397 to 3.175 mm (1/64 to 1/8). of an inch). The refractory ring insert 72 is thus locked mechanically to the outlet end of the fuel injection nozzle 10 in the vicinity of the outlet orifice 40. The horizontal annular surface 62 at the output end 14 has direct exposure to the reaction zone of the fuel injection nozzle and from this a substantial protection of the described positioning and a fixation of the refractory protective member 70 to said annular surface 62 derives. horizontal. Since the refractory annular insert 72 of the protective member 70 is mechanically locked by means of the immobilization bolts 110 to the fuel injection nozzle structure and such bolts of immobilization have a strength and duration greater than the mortar, the immobilization bolts prolong the life of the refractory member 70 as a protective agent for the outlet end 40 of the fuel injection nozzle 10. The submerging or retraction of the refractory annular insert 72 inside the metallic structure of the fuel injection nozzle at the end 40 of the outlet nozzle, ensures that the refractory annular insert 72 provides the desired protection without substantial exposure of the surface to adverse conditions in the reaction zone of the gasifier. The useful life of the fuel injection nozzle is thus prolonged by the increase in resistance to thermal deterioration and thermochemical degradation of the nozzle outlet end 40 of the fuel injection nozzle.

Another embodiment of the fuel injector nozzle has been indicated in general with the reference number 120 in Figure 6. The fuel injector nozzle 120 is structurally similar to the fuel injection nozzle 10, unless otherwise indicated. The fuel injector nozzle 120 has an outlet end 122 provided with an outlet orifice 124 and a horizontal annular surface 126 at the outlet end of the exit orifice 124. A trapezoidal channel 130 (Figure 6) corresponding to the channel 90 of the fuel injector nozzle 10 (Figure 2), has been formed on the annular surface 126. As shown more clearly in Figure 10, the channel 130 includes an upper base surface 132, an internal radial surface 134, an external radial surface 136, and a channel opening 138. A threaded protrusion 144 has been formed on the inner radial surface 134 and extends approximately 240 ° around the channel 130. A threaded-like protrusion 146 has been formed on the outer radial surface 136 and is also extends approximately 240 ° around channel 130 in arcuate alignment with protrusion 144. Thus, a 120 ° arc portion 148 (Figure 7) of channel 130 is free of protrusions 144 and 146 in the manner of a thread.

Thread-like protuberances 144 and 146 are located at about one third of the distance between channel opening 138 and upper passage 132. The protuberances 144 and 146 are of generally semi-elliptical or semicircular cross-section, although other suitable shapes are also possible. With reference to Figure 6, the fuel injector nozzle 120 further includes a multi-segment annular insert 150, formed with the same material as the annular insert 72. The insert 150 is trapezoidal in shape complementary to the channel 130, and includes three segments 152, 154 and 156, each of which has an arcuate extension of approximately 120 °. As shown more clearly in Figure 10, each of the segments 152, 154 and 156 includes a relatively narrow upper surface 162, a relatively wide lower surface 164, a radially internal surface 166, and a radially external surface 168 that they correspond to the channel opening 130 and to the channel surfaces 132, 134 and 136. An internal circumferential groove 172 is formed in the radially internal side 166 of the segments 152, 154 and 156, to receive the protrusion 144, and an outer circumferential groove 174 has been formed in the outer radial sides 168 of the segments 152, 154 and 156 to receive the protrusion 146. The end portions of each of the segments 152, 154 and 156 are staggered, as indicated by reference numerals 180 and 182, to allow a stepped engagement of the segments, as shown more clearly in Figures 11 and 12. Thus, one end of the segment 152 includes the descending step 182 capable of engaging with the ascending step 180 complementarily, at an adjacent end of the segment 154. The opposite ends of each of the segments 152 and 154 include an ascending step 180. Segment 156 has opposite end portions that are each provided with step down 182.

The segments 152, 154 and 156 are located in the channel 130 by arranging such segments, one by one, in the portion 148 without protrusion of the channel 130, and by sliding the segments towards the portion 130 of the channel including the protuberances. and 146. It will be appreciated that the nub-free portion 148 of the channel 130 has an arcuate extension that is slightly larger than the arcuate extension of the larger segment of a multi-segment insert. Although the insert 150 includes three segments of approximately the same arc, each segment need not be of equal size. Preferably, the insert should not exceed four segments. Thus, the segment 152 is arranged in the protrusion-free portion 148 (Figure 7) of the channel 130, and is threaded in an anti-clockwise direction, to the position shown in Figure 8. The next segment 154 is disposed at the portion 148 without protrusion of the channel 130, and threaded counterclockwise to the position shown in Figure 8, into which the staggered end portions 180 and 182 fit, as shown in Figure 11. remaining segment 156 is arranged in the protrusion-free section 148, such that the ascending steps 180 of each end of segment 156, fit with respective descending steps 182 of the corresponding ends of segments 152 and 154. When the three segments 152, 154 and 156 have been placed in channel 130, are rotated approximately 60 degrees counterclockwise, for example, as indicated by arrows 188 and 190 of Figure 9. In this way, a portion of the segments 152 and 156 is engaged by the threads 144 and 146 in the manner of protuberances, while the complete arched extension of the segment 154 is engaged by the threads 144 and 146 as a protrusion. Under this arrangement, each of the segments 152, 154 and 156 has at least one 60-degree fit with the internal and external threads 144 and 146 in the manner of protuberances.

The segments 152, 154 and 156 are thus keyed in the channel 130 by inter-engaging between the threads 144 and 146 of the protuberant channel and the slots 172 and 174 of the segment. Such inter-engagement serves to maintain the segments 152, 154 and 156 securely within the channel 130. In addition, the stepped engagement of the opposite ends of each of the segments 152, 154 and 156 minimizes the likelihood of that the corrosive materials reach the surface 92 of the channel 130. If desired, the end portions 180 and 182 fitted in step form of each of the segments 152, 154 and 156, can be joined by ceramic mortar or with any other material of known good bonding. The bonding material can also be applied to the surface of the channel 140 during the installation of the segments 152, 154 and 156. The joints 180 and 182 as a step, at the ends of each of the segments 152, 154 and 156, help combat the penetration of liquid corrosive slag and hydrogen sulfide beyond the ceramic segments. The multi-segment annular ring, allows the expansion and contraction of the segments, and the end portions fitted as a step minimize the penetration of corrosive materials beyond the ceramic segments, even though no bonding material has been provided between the segments. end portions 180 and 182 fitted as a step of each of the segments 152, 154 and 156. Another embodiment of the fuel injection nozzle has been indicated in general with the reference number 200 in Figure 12. The injection nozzle 200 of fuel is structurally similar to the nozzle 10 fuel injection, unless otherwise indicated. The fuel injector nozzle 200 has an outlet end 202 provided with an outlet orifice 204, and a horizontal annular surface 206 at the exit end of the exit orifice 204. A trapezoidal channel 210 shown partially in Figures 12 and 15, and completely in Figure 17, corresponds to the channel 90 of the fuel injection nozzle 10 and is provided with a horizontal annular surface 206. The trapezoidal channel 210 includes a top base portion 212, an internal radial surface 214 (Figure 17), an outer radial surface 216, and a base opening 218 (Figure 17). A threaded protrusion 222 is formed on the outer radial surface 216, and has an arcuate extension of approximately 240 degrees around the surface 216. Thus, an arc of 120 degrees of the surface 216, indicated with the number 224 of reference in Figure 12, is free of the protrusion 222 as a thread. A threaded protrusion 226 (Figure 17) has been formed on the inner radial surface 214 of the channel 210 and extends completely around the channel. With reference to Figure 12, the fuel injector nozzle 200 further includes a refractory annular multi-segment insert 230, identical to the refractory annular refractory multi-segment 150 insert. 120 fuel injection. The fuel injector nozzle 200 also includes a multi-segment metal retainer ring 240, which includes four segments 242, 244, 246 and 248. The ring segment 242 has an arcuate extension of approximately 180 degrees. The ring segment 244 has an arcuate extension of approximately 120 degrees. The segment Ring 246 has an arcuate extension of approximately 50 degrees, and ring segment 248 has an arched extension of approximately 10 degrees. Each of the ring segments 242, 244, 246 and 248 have an outer radial surface 214 provided with protrusion 226 as a thread. The outer radial surface 214 of the retaining ring 240, as shown in Figure 12, also constitutes the internal radial surface 214 of the channel 210, as shown in Figure 17. The ring segments 242, 244, 246 and 248, they also include an upper edge 252 that engages an adjoining surface 254 (Figure 16), adjacent to the upper base 212 of the trapezoidal recess 210. The segments 242, 244, 246 and 248 further include a radially internal surface 258 and the lower edge 256 (Figure 17) corresponding to the lower surface 164 of the annular insert 230. The insert segments 152, 154 and 156 of the annular refractory insert 230 are mounted on the output end 202 of the fuel injection nozzle 200 before the retaining ring 240 is installed. For example, the segment 152 of insert is placed in the bulge-free portion 224 of the recess 210, and moves around the recess 210 in a manner similar to that previously described for the installation of the annular insert 150, to allow inter-engagement between the boss 222 as a thread and slot 174 as a thread. The insert segment 152 is completely displaced by the protrusion-free portion 224. The next insert segment 154 is disposed in the protrusion-free section 224 and is also displaced, in a manner similar to that previously described, such that the protrusion 222 fits into the slot 174 of the insert segment 154. Insert segment 154 also moves outwardly from portion 224 without protrusion to fully engage protrusion 222. Remaining insert segment 156 is disposed in portion 224 without protrusion, and is displaced approximately 60 degrees in a manner similar to which has been previously described, up to the position shown in Figure 13, in such a way that the protrusion 222 fits in approximately 60 degrees of the slot 174 of the insert segments 152 ^ and 156, while the insert segment 154 is inter-engages with the protrusion 222, as shown more clearly in Figure 13. The stepped end portions 180 and 182 of each of the insert segments 152, 154 and 156, engage in a manner similar to that which has been engaged. described and represented in the foregoing.

After the insert segments 152, 154 and 156 have thus been installed, they are fixed in their position securely by means of the retaining ring 240. The retaining ring segments 242, 244 and 246 are positioned sequentially as shown in Figures 14 and 17, such that the protrusion 226 of the ring segments fits into the slot 172 of the segments 152, 154 and 156 of the insert. The segment 248 of the ring is pressed into position to complete the circumference of the retaining ring and constitute the radially inner wall surface 214 of the trapezoidal recess 210 that houses the annular insert 230. The upper edge 252 of the segments 242, 244, 246 and 248 of the retaining ring is soldered or otherwise appropriately fixed to the adjacent surface 254 (Figures 16 and 17). The ring segment end portions 262, 264, 266, 268, 270, 272 and 274 (Figures 12 and 14) are also welded together to form an integral retainer ring for securing the segments 152., 154 and 156 of the insert at the outlet end 202 of the fuel injector nozzle 200 in the exit orifice 204. Preferably, the end portions 262-274 of the segments 242-248 of the retaining ring are staggered with respect to the staggered end portions 180 and 182 of the segments 152-156 of the insert. If desired, a suitable known high temperature adhesive can be provided on the outer radial surface 214 of the segments 242-248 of the retaining ring, and on the internal radial surface 166 of the segments 152-156 of the insert. It will be noted that, since the arcuate extension of the segments 242, 244 and 246 of the retaining ring is approximately 360 degrees, the retaining ring segment 248 can be replaced by a weld formation. Other different combinations of arched configuration of the retaining ring segments can be used as an option. The number of segments of the retaining ring is also optional, although a minimum of two segments of the retaining ring is preferred. Under this arrangement, the fuel injector nozzle 200 is provided with a refractory protective insert in the outlet nozzle 204, which is relatively easy to install. The refractory ring 230 is retained securely in the channel 210, without the need for bonding materials, which are optional, as is the case in all embodiments of the invention. Some advantages of the invention, evident from the foregoing description, include a fuel injection nozzle provided with a refractory ring insert that is mounted flush at the outlet end proximate to the outlet portion of the nozzle. The refractory protective insert can be easily installed, repaired or replaced, and is mechanically fixed so that it engages with the structure of the fuel injection nozzle. The refractory protective insert allows a uniform wall thickness between the insert and the outlet orifice, and thus withstands thermal deterioration and thermochemical degradation, better than the metal it replaces. The refractory protective insert thus prolongs the service life of the fuel injection nozzle. In view of the foregoing, it will be appreciated that the various objects of the invention have been achieved, and that other advantageous results have been achieved. Since various changes can be made in the constructions and in the foregoing method without departing from the scope of the invention, it is intended that everything contained in the above description or represented in the accompanying drawings be interpreted as illustrative and not in limiting sense.

Claims (10)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty, and therefore, what is claimed in the following claims is claimed as property: 1. A fuel injector nozzle for a gasifier which comprises: a) a body for injecting the fuel that has an upper end and a lower end, b) inner and outer concentric ducts extending from the upper end to the lower end to allow the segregated passage of an oxygen-containing gas jet and a carbonaceous jet of fuel from the lower end , c) the lower end of the fuel injector nozzle having an outlet orifice and a lower end surface, said lower end surface being formed by a recess, and d) an annular refractory insert held within said recess to provide thermal and thermochemical protection to the fuel injector nozzle at the lower end, having said ins refractory ring an uncovered final surface that does not cover the surface of the lower end along the cavity and is practically coplanar with the surface of the lower end of said fuel injector nozzle.
2. 2. A fuel injector nozzle, according to claim 1, characterized in that the cavity has the shape of a channel defining an annular path.
3. 3. A fuel injector nozzle, according to claim 2, characterized in that the annular refractory insert is a one-piece element, and in addition said fuel injection nozzle includes retaining means for holding the annular refractory insert inside said channel .
4. 4. A fuel injector nozzle, according to claim 2, characterized in that the annular refractory insert is formed by a series of insert segments.
5. A fuel injector nozzle according to claim 4, characterized in that said channel includes surfaces of opposite walls and said retaining means includes a projecting part placed on at least one wall surface of said channel and is provided, at least one slot within said insert segments for mutual coupling between the projection portion and the slot when said insert segments are within said channel, such mutual coupling serving to retain said insert segments within said channel.
6. 6. A fuel injector nozzle according to claim 5, characterized in that the protruding part extends in part around the circumference of one of said walls, such that a predetermined arched extension of one of said walls is without said protrusion.
7. 7. A fuel injector nozzle according to claim 6, characterized in that said predetermined arcuate extension is slightly larger than the arcuate extension of the larger insert segment.
8. A fuel injection nozzle, according to claim 7, characterized in that said retention means include one of said protruding portions on each of the surfaces of opposite walls of said channel and because each of said insertion segments have opposite lateral surfaces. and the retaining means includes one of said grooves in each of the opposite side surfaces of said insert segments.
9. 9. A fuel injector nozzle, according to claim 4, characterized in that said insert segments have opposite end portions which are staggered in a complementary manner to allow stepped coupling of the insert segments within the channel.
10. 10. A fuel injector nozzle, according to claim 2, characterized in that said recess has an assembled side wall attached to the lower end of said outlet orifice after said annular refractory insert has been placed within said recess, in such a way that said assembled side wall completes the embodiment of the channel shape of said cavity. SUMMARY The fuel injection nozzle for a gasifier includes a refractory protective sheath that has been flush mounted to an outlet end near the outlet portion of the nozzle. The refractory insert is annular in shape to surround the outlet of the nozzle. The refractory annular member can be a one-piece structure or a multi-segment structure, preferably no more than four pieces. If the refractory annular member is a one-piece structure or a multi-segment structure, it is recessed in an outlet end surface of the fuel injection nozzle, and retained in the recess by means of locking bolts or by means of an attachment to thread mode between a projection and a groove provided on complementary surfaces for inter-engaging the recess and the refractory member. The retaining structures provided in the refractory annular member and in the recess in which the refractory member is disposed securely hold the refractory annular member in position. The long-lasting presence of the refractory annular member prolongs the service life of the fuel injection nozzle by protecting the vulnerable surface areas at the exit end of the fuel injection nozzle that are close to a hot and corrosive reaction zone inside the gasifier .