WO2000007910A1

WO2000007910A1 - Providing fuel modules to preheater/precalciner kilns

Info

Publication number: WO2000007910A1
Application number: PCT/US1999/017441
Authority: WO
Inventors: James Ronald Tutt
Original assignee: Cadence Environmental Energy, Inc.; Ash Grove Cement Company
Priority date: 1998-08-05
Filing date: 1999-08-04
Publication date: 2000-02-17
Also published as: TW430734B

Abstract

A fuel charging apparatus (10) is configured to charge fuel modules (16) through an aperture formed in a vessel (18). The fuel charging apparatus (10) includes a lost motion fuel charging mechanism (14) and a power mechanism (12). The lost motion fuel charging mechanism (14) includes a fuel module support (22), that engages and moves the fuel module (16), and a fuel module support cleaner (24). The power mechanism (12) is coupled to the fuel module support (22) to move the fuel module support (22) relative to the fuel module support cleaner (24) to clean the fuel module support (22).

Description

PROVIDING FUEL MODULES TO PREHEATER/PRECALCINER KILNS

Field of the Invention

The present invention relates to use of solid wastes in preheater/precalciner kilns. More particularly, this invention is directed to an apparatus and method for feeding combustible solid waste into the riser duct of a preheater or precalciner kiln for combustion within the riser duct.

Background and Summary of the Invention Solid combustible wastes have always been generated by industry.

Many of such wastes, because of their flammable or toxic character, are categorized by applicable environmental regulations as "hazardous wastes". Prior to governmental regulation of the disposal of such materials, they were disposed of in landfill operations with significant environmental consequences. With recently enacted environmental regulations imposing severe restrictions on landfill-type disposal of hazardous wastes, the only viable means for their safe disposal has been by thermal treatment, typically at high cost in specialized hazardous waste incinerators equipped with extensive emission control devices.

Cement kilns have received favorable review from both federal and state environmental regulatory agencies as providing ideal conditions for disposal of combustible waste materials. The production of cement clinker in a cement kiln is an energy intensive operation. The use of combustible waste-derived fuel in a cement kiln provides inexpensive energy values for the cement making process with concomitant saving of non-renewable fuel sources. Thus, burning solid waste in operating kilns allows recovery of energy values from hazardous wastes. Also, because of high kiln operating temperatures, long residence times and their ability to provide favorable conditions for the chemical combination of inorganic residues into active compounds of portland cement, cement manufacturing operations provide ideal conditions for environmentally sound disposal of both hazardous and non-hazardous combustible waste materials.

Cement clinker is produced by heating calcareous material with an argillaceous material or other forms of silica, alumina, and iron oxide which may additionally include minor amounts of materials indigenous to these raw materials at temperatures on the order of about 2300°-2900°F. (1260° - 1593°C.) to bring about the chemical reactions necessary to convert the ingredients to cement clinker. In conventional long wet or dry process kilns, calcining and clinkering of cement raw mineral materials are accomplished by passing finely divided raw mineral materials through a rotating inclined rotary vessel heated at its low end.

Inasmuch as high temperatures are required for this process, fuel costs constitute a significant factor in the ultimate cost of the product. In particular, it is art recognized that the most significant factor in overall fuel costs for the production of cement clinker is the highly endothermic calcining step during which alkali metal carbonates are converted to their corresponding oxides with the concomitant generation of carbon dioxide. This portion of the cement manufacturing process accounts for over 70% of the theoretical energy requirements of a typical dry process. Accordingly, methods of reducing fuel costs have been and still remain a major focus for the cement manufacturing industry. One development directed at realizing substantial fuel savings was the construction and use of precalciner kilns in which the finely divided raw material is suspended with burning fuel with high heat transfer efficiency. Precalciners utilize a special chamber, a riser duct, for combustion of up to 60% of the total process fuel in suspension with preheated raw mineral materials from a conventional suspension preheater system to rapidly (typically 1-2 seconds) calcine about 90% of the calcium carbonate in the raw mineral feed to calcium oxide.

The intimate contact between the suspended mineral particles and the burning fuel, result in excellent thermal efficiency and substantial fuel savings (among other benefits) as compared to the conventional long wet or dry rotary kilns. See, Garrett, Rock Products, "Precalciners Today-A Review", pp. 39 et seq., July, 1985, for a detailed description of precalciners.

Another type of cement kiln developed with view of energy savings is a preheater kiln. Preheater kilns are also constructed with a riser duct and typically a multistage cyclone system in which the raw mineral materials are suspended in the hot kiln gas stream generated by the burner providing heat for the clinker portion of the process. Unlike the precalciner configuration, no additional fuel is combusted in the riser duct of a preheater kiln and as a consequence of the lower temperatures the raw mineral material is typically not heated to calcining temperatures. However, because the raw mineral material is efficiency heated in the kiln gas stream before it enters the rotary vessel portion of the kiln, the required length of the rotary vessel portion of the kiln (and thus the residence time of the mineral in the rotary vessel) is substantially reduced.

It is known to charge solid waste into the rotary vessel of a cement kiln for environmentally sound recovery and use of energy values from such waste products. See U.S. Patent No. 4,850,290 to Benoit et al. It is also known to charge the solid waste, for example, containerized waste or whole tires into a shelf-transition portion of a precalciner or preheater cement kiln. See U.S. Patent No. 4,850,290 to Benoit et al. The shelf-transition portion is located between the riser duct and rotary vessel. In a precalciner, feeding solid waste-derived fuel into the shelf-transition portion results in a savings of up to about 10% of the process fuel. The apparatus and method of the present invention can be utilized to optimize compliance with applicable environmental emission standards and they also enable a most efficient use of solid wastes as supplemental fuel in cement manufacturing without compromising quality of the processed mineral product. Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiments exemplifying the best mode of carrying out the invention.

Brief Description of the Drawings Fig. 1 is a diagrammatic view of a fuel charging apparatus showing the fuel charging apparatus having a power mechanism and a two part lost motion mechanism that is moved by the power mechanism to move a fuel module through an aperture of a vessel;

Fig. 2 is a diagrammatic view similar to Fig. 1 showing the lost motion mechanism including a fuel module support that is adapted to engage and move the fuel module and a fuel module support cleaner, the fuel module support cleaner and fiiel module support are movable relative to each other by the power mechanism to clean the fuel module support;

Fig. 3 is a diagrammatic view similar to Fig. 2 showing the fuel charging apparatus including a valve that substantially isolates substances in the vessel from an environment outside the vessel, the fuel module support is cleaned by the fuel module support cleaner in a location isolated from the environment outside the vessel;

Fig. 4 is a side elevational view of a fuel charging apparatus positioned adjacent to a riser duct of a preheater/precalciner kiln;

Fig. 5 is an exploded perspective view of a portion of the fuel charging apparatus showing the fuel charging apparatus including the power mechanism, the two-piece lost motion mechanism, a charger housing, and a charger frame, the power mechanism being a hydraulic ram, and the lost motion mechanism being a fork and a platen assembly;

Fig. 6 is a perspective view, with portions cutaway, of a portion of the fuel charging apparatus showing the fuel charging apparatus including a fuel module feeder mechanism and the charger housing;

Fig. 7 is a side elevation view, with portions cutaway, of the fuel charging apparatus, showing a first tire lying in the charger housing adjacent to the platen assembly of the lost motion mechanism and a second tire being fed into the fuel module feeder mechanism;

Fig. 8 is a side elevation view similar to Fig. 7 showing the fork moved relative to the platen assembly so that prongs of the fork are positioned to lie above and under the first tire and the second tire positioned to lie within the fuel module feeder mechanism; Fig. 9 is a side elevation view similar to Fig. 8 showing the fork supporting the first tire in the riser duct and the second tire being moved through the fuel module feeder mechanism;

Fig. 10 is a side elevation view similar to Fig. 9 showing the fork member being withdrawn away from the riser duct relative to and through the platen assembly; Fig. 11 is a front elevation view of the charger frame, charger housing, and lost motion mechanism showing the platen assembly having prong-receiving apertures and cleaning collars positioned to lie around the prong-receiving apertures;

Fig. 12 is a sectional view, taken along line 12-12 of Fig. 11, showing residue from the fuel module being scraped off of a prong of the fork as the prong is retracted through the cleaning collar of the platen assembly;

Fig. 13 is a side elevation view similar to Fig. 10 showing the platen assembly and fork being moved away from the riser duct so that the second tire may be placed within the charger housing; Fig. 14 is a side elevational view similar to Fig. 4 showing an alternative location of the fuel charging apparatus adjacent to a tertiary air duct that feeds into the riser duct; and

Fig. 15 is an elevational view, with portions cutaway, of yet another alternative location of the fuel charging apparatus adjacent to the riser duct upstream of a shelf-transition portion that is positioned to lie between the riser duct and rotary kiln.

Detailed Description of the Preferred Embodiment

A fuel charging apparatus 10 having a power mechanism 12 and a lost motion fuel charging mechanism 14 is provided to feed or charge fuel modules 16 into a vessel 18 as shown in Fig. 1. A fuel module 16 may be any type of waste or other type of fuel and may be in any form such as solid, containerized liquid, etc. The fuel charging mechanism 14 includes multiple components 20 that move relative to each other. In a preferred embodiment of the present invention, the components 20 include a fuel module support 22 and a fuel module support cleaner 24 as shown in Fig. 2. The fuel module support 22 engages a fuel module 16 and supports fuel module 16 within vessel 18. The fuel module support cleaner 24 removes residue from the fuel module support 22.

In a preferred embodiment of the present invention, the components 20 further include a valve 26 as shown in Fig. 3. The valve 26 isolates and closes the vessel 18 and an associated vessel environment from a selected non-vessel environment. The valve 26 permits the fuel module support cleaner 24 to remove residue from fuel module support 22 in the vessel 18 or associated vessel environment that is isolated from the selected non-vessel environment.

In a preferred embodiment, the fuel charging apparatus 10 is a fuel charging apparatus 30 and the vessel 18 is a riser duct 32 of a preheater/precalciner kiln 34 as shown in Fig. 4. The preheater/precalciner kiln 34 further includes a rotary kiln 36.

In the widely used commercial process for the production of cement clinker, cement raw materials are calcined and "clinkered" by passing finely divided raw mineral materials through a rotating inclined rotary kiln vessel or kiln cylinder 36. The requisite temperatures for processing the mineral material are achieved by burning fuel such as gas, fuel oil, powdered coal and the like at the lower end of the kiln 36 with the kiln gases moving countercurrent to the mineral materials moving through the rotating kiln cylinder 36.

Preheater or precalciner kilns 34 have, in addition to the inclined rotating kiln vessel 36 fired at its lower end, a stationary heat transfer portion at its upper end, typically including multistage cyclones (not shown), for preheating or precalcining the mineral material before it is introduced into the upper end of the rotating kiln cylinder 36. Because the mineral material is preheated or precalcined before entering the rotating kiln vessel 36, the length of the rotating kiln vessel 36 can be much shorter than a kiln vessel in conventional long kilns (not shown) not having a preheater or precalciner. The present invention provides a method and apparatus for controlled, environmentally sound, highly efficient burning of solid combustible wastes as supplemental fuel in the stationary heat transfer portion of preheater or precalciner kilns 34. Kiln gas flows from rotary kiln vessel 36 into and upward through riser duct 32. The mineral material flows countercurrent to the kiln gas stream by falling downwardly through riser duct 32 into rotary kiln vessel 36 and then passing through rotary kiln vessel 36. The heated kiln gas stream flowing upwardly through riser duct 32 heats the mineral material as it falls down through riser duct 32 and in serial cyclones (not shown) downstream relative to kiln gas flow, of the riser duct 32. The mineral material is finely crushed to permit good heat transfer between the heated kiln gas stream and the mineral material. Use of fuel charging apparatus 30 in preheater/precalcmer kiln 34 to burn fuel modules 16 in the riser duct 32 allows significant reduction of the amount of fuel needed to supply the energy requirements of the preheater/precalciner kiln 34 Fuel charging apparatus 30 is shown m more detail in Figs 5 and 6 Fuel charging apparatus 30 includes a power mechanism 12, a lost motion fuel charging mechanism 14, a charger housing 38, a charger frame 40, and a fuel module feeder mechanism 42 as shown in Figs 5 and 6 The power mechanism 12 of fuel charging apparatus 30 is a hydraulic ram 44 In alternative embodiments, any type of device may be used to move the lost motion fuel charging mechanism

The fuel module support 22 of lost motion fuel charging mechanism 14 of fuel charging apparatus 30 is a fork 46 and fuel module support cleaner 24 and valve 26 of lost motion fuel charging mechanism 14 of fuel charging apparatus 30 is a platen assembly 48 Lost motion fuel charging mechanism 14 of fuel charging apparatus 30 further includes a stop device 43 that permits movement of fork 46 relative to platen assembly 48 Fork 46 includes a back plate 50, six-spaced apart prongs 52, 54, 56,

58, 60, 62, guide tabs 64, 66, 68, and a mounting collar 70 as shown in Fig 5 Back plate 50 includes a front side 72 facing toward platen assembly 48 and a back side 74 facing away from platen assembly 48 Mounting collar 70 is connected to back side 74 of back plate 50 and configured to couple to hydraulic ram 44 as shown, for example, in Fig 7 The prongs 52, 54, 56, 58, 60, 62 are connected to front side 72 of back plate 50 and extend away from hydraulic ram 44

Platen assembly 50 is box shaped and includes a front wall 76 facing away from hydraulic ram 44, a back wall 78 facing toward hydraulic ram 44, first and second side walls 80, 82 extending between front and back walls 76, 78, and a top wall 84 as shown, for example, in Figs 5 and 7 Front wall 76 is formed to include five prong-receiving apertures 86, 88, 90, 92, 94 that receive prongs 52, 54, 56, 58, 60, respectively, as shown, for example, in Figs 5 and 7 Back wall 78 is formed to include six prong-receiving apertures 96, 98, 110 (three others not shown) that receive prongs 52, 54, 56, 58, 60, 62 as shown, for example, in Fig 7 Prong 62 includes a threaded end 112 and extends through prong- receiving aperture 98 formed in back wall 78 as shown in Figs 5 and 7 The lost motion fuel charging mechanism 14 of fuel charging apparatus 30 further includes a coupler 114 that engages threaded end 112 of prong 62 as shown in Fig 7 The first and second side walls 80, 82 of platen assembly 50 are formed to include an access apertures 116, 1 17 to permit access to the interior of platen assembly 48 so that coupler 114 may be threaded onto and off of prong 62 as shown in Figs 5 and 7 Platen assembly 48 further includes six guide tabs 118, 120, 122, 124

(two others not shown) as shown in Figs 5 and 7 Three of the guide tabs 118, 120, 122 are connected to front wall 76 and three of the guide tabs 124 (two others not shown) are connected to back wall 78.

The charger housing 38 includes main housing body 126 and a housing tip 128 as shown in Figs 5 and 7 The housing tip 128 is coupled to the main housing body 126 as shown, for example, in Fig 7 Housing tip 128 extends into riser duct 32 and is thus exposed to the high temperatures of riser duct as shown in Fig 7 Housing tip 128 is made of a heat tolerant material because it is exposed to the high temperatures of riser duct 32 The main housing body 126 does not need to be made of the more expensive heat tolerant material because main housing body 126 is spaced apart from riser duct 32 In preferred embodiments, the components of fuel charging apparatus 30 in close contact with the high temperatures of riser duct 32 such as housing tip 128, platen assembly 48, and fork 46 are made of an alloy steel such as 310 stainless steel In preferred embodiments, the housing tip 128 is coated with a ceramics insulation material 129 as shown, for example, in Fig. 7

The main housing body 126 includes a top wall 130, bottom wall 132, and first and second side walls 134, 136 extending between top and bottom walls 130, 132 as shown in Fig 5 The top, bottom, and side walls 130, 132, 134, 136 define a forward or vessel opening 138 and rearward opening 140 as shown in Figs 5 and 7 The top wall 130 is formed to include a fuel module-receiving aperture 142

The main housing body 126 further includes four spaced-apart guide rails 144, 146, 148, 150 that are coupled to bottom wall 132 The guide rails 144, 146, 148, 150 define guide slots 152, 154, 156 as shown in Fig 5 Guide tabs 64, 66, 68 of fork 46 and guide tabs 118, 120, 122, 124 of platen assembly 48 are positioned to lie in guide slots 152, 154, 156 to couple fork 46 and platen assembly 48 to main housing body 126 as shown, for example, in Fig 7 The housing tip 128 includes a top wall 158, a bottom wall 160, and first and second side walls 162, 164 extending between top and bottom walls 158, 160 as shown in Fig. 5. The top, bottom, and side walls 158, 160, 162, 164 define forward and rearward openings 166, 168. The housing tip 128 further includes four spaced- apart guide rails 170, 172, 174, 176 that are coupled to bottom wall 160. The guide rails 170, 172, 174, 176 define guide slots 178, 180, 182 as shown in Fig. 5. Guide tabs 118, 120, 122 of platen assembly 48 are positioned to lie in guide slots 178, 180, 182 to couple platen assembly 48 to housing tip 128 as shown in Fig. 11.

The housing tip 128 further includes a mounting flange 184 surrounding the rearward opening 168 and the main housing body 126 further includes a similar mounting flange 186 surrounding forward opening 138 of housing tip 128. The housing tip 128 is coupled to main housing body 126 by bolting or otherwise coupling mounting flange 184, 186 as shown in Fig. 7. The housing tip 128 and main housing body 126 are coupled so that guide rails 144, 146, 148, 150 of main housing body 126 are aligned with guide rails 170, 172, 174, 176 of housing tip 128 and guide slots 152, 154, 156 of main housing body 126 are aligned with guide slots 178, 180, 182 of housing tip 128.

The guide tabs 118, 120, 122, 124 of platen assembly 48 and guide tabs 64, 66, 68 of fork 46 slide through the aligned guide slots 152, 154, 156, 178, 180, 182 of charger housing 38. In preferred embodiments, a bearing surface is provided between guide rails 144, 146, 148, 150, 170, 172, 174, 176 of charger housing 38 and platen assembly 48 and fork 46. In preferred embodiments, the bearing surface is a Lubriplate™ product that is painted on guide rails 144, 146, 148, 150, 170, 172, 174, 176 of charger housing 38 about every 24 hours. The charger frame 40 includes a base 188, legs 190 extending downwardly from base 188, and casters 192 coupled to the legs 190. The casters 192 are configured to roll on rails 193 as shown in Figs. 4, 7, and 11. The casters 192 and rails 193 permit fuel charging apparatus 30 to be pushed and pulled into the proper position relative to riser duct 32. The charger frame 40 further includes a power mechanism mount 194 to which hydraulic ram 44 is coupled as shown in Figs. 5 and 7. The stop device 43 includes an actuator 196, a first linkage assembly 198, a first stop pin 210, a rod 212, a second linkage assembly 214, and a second stop pin 216 as shown in Fig 5 Each of the first and second linkage assemblies 198, 214 includes first, second, third, and fourth links 218, 220, 222, 224 The actuator 196 and first and second links 218, 220 of linkage assemblies 198, 214 are coupled to charger frame 40 as shown in Fig 7 The rod 212 includes a first end 226 coupled to first linkage assembly 198 and a second end 228 coupled to second linkage assembly 214 The first stop pin 210 is coupled to third and fourth links 222, 224 of first linkage assembly 198 and second stop pin 216 is coupled to third and fourth links 222, 224 of second linkage assembly 214 as shown in Fig 7

Actuator 196 is coupled to first linkage assembly 198 and rod 212 to move stop pins 210, 216 as shown, for example, in Figs 7 and 9 Bottom wall 132 of main housing body 126 of charger housing 38 is formed to include stop pin-receiving apertures 230 that receive stop pins 210, 216 as shown, for example, in Figs 7 and 9 Actuator 196 moves linkage assemblies 198, 214 and rod 212 to move stop pins 210, 216 between an upwardly extended position within charger housing, shown in Fig 7, and a downwardly retracted position as shown in Fig 9

The fuel module feeder mechanism 42 includes a feeder housing 232, a conveyor 234, a carrier 236, and a door mechanism 238 as shown in Fig 6 The feeder housing 232 is formed to include an upwardly facing fuel module-receiving opening 240 and a downwardly facing fuel module delivery opening 242 The feeder housing 232 includes ball bearings 233 on which carrier 236 slides

The conveyor 234 includes a power mechanism 244 and a chain link drive system 246 The carrier 236 is coupled to the chain link drive system 246 to be moved by the conveyor 234 The chain link drive system 246 properly orients the carrier 236 The feeder housing 232 further includes guides 235 The carrier 236 contacts guides 235 only if the carrier 236 is not aligned with the chain link drive system 246 In preferred embodiments, the guides 235 are strips of ultra high molecular weight polymer (UHMWP)

The feeder housing 232 also includes stops 239 at a front end 241 and a rear end 243 of feeder housing 232 The carrier 236 contacts stops 239 as the carrier 236 is moved through feeder housing 232 by conveyor 234 In preferred embodiments, the stops 239 are strips of ultra high molecular weight polymer (UHMWP) The carrier 236 includes a flat plate 248 and spaced-apart posts 250 connected to the flat plate 248. The door mechanism 238 includes an actuator 252, a door 254, and a linkage 256 extending between actuator 252 and door 254. The actuator 252 and linkage 256 move door 254 as shown, for example, in Figs. 6, 8, and 9. The door 254 is formed to include slots 258 that are sized to permit posts 250 of carrier 236 to pass through slots 258.

The movement of the components of fuel charging apparatus 30 during the process of charging a fuel module 16 into riser duct 32 is shown in Figs. 7-13. Riser duct 32 is formed to include an aperture 270 and the housing tip 128 of fuel charging apparatus 30 extends into and through aperture 270. In the illustrated embodiment, the fuel module 16 is a tire 260. The process of feeding a tire 260 into charger housing 38 and then charging the tire 260 into riser duct 32 is illustrated using first, second, and third tires 260, 262, 264 in Figs. 7-10 and 13.

In Fig. 7, first tire 260 is positioned to lie in charger housing 38 and second tire 262 is positioned on a conveyor 266 that is used to load fuel modules 16 into upwardly-facing fuel module-receiving opening 240 of fuel module feeder mechanism 42. The stop pins 210, 216 are in their upwardly extended position to prevent platen assembly 48 from being moved in direction 268 toward riser duct 32. The door 254 of door mechanism 238 is closed to substantially prevent any flow between riser duct 32 and the environment outside of fuel charging apparatus 30. Typically, the riser duct 32 is at a negative pressure relative to atmospheric pressure and at a very high temperature relative to the temperature outside of fuel charging apparatus 30. In the absence of any type of obstruction such as door 254, ambient air from the environment outside of fuel charging apparatus 30 would flow into riser duct 32 and cool the riser duct 32. This type of flow into riser duct 32 would adversely effect the operational control of the temperatures and amount of oxygen within the riser duct 32.

In Fig. 8, the hydraulic ram 44 moves fork 46 in direction 268 along axis 296 relative to platen assembly 48 because stop pin 210 continues to prevent movement of platen assembly 48 in direction 268. This lost motion movement of fork 46 relative to platen assembly 48 positions prongs 52, 54, 56, 58, 60 over and under first tire 260. The prongs 52, 54, 56 that are positioned below first tire 260 lie in guide slots 152, 154, 156 of main housing body 126. The second tire 262 has dropped off of conveyor 266 in direction 272 in fuel module feeder mechanism 42.

In the illustrated embodiment of the invention, the lost motion between fork 46 (fuel module support 22) and platen assembly 48 (fuel module support cleaner 24) is lost motion along axis 296. In alternative embodiments, the lost motion between the fuel module support and fuel module support cleaner may be movement of either component relative to the other in any manner.

In Fig. 9, the actuator 196 of stop device 43 moves linkage assemblies 198, 214 and rod 212 in direction 274 to move stop pins 210, 216 downwardly in direction 276 so that stop pin 210 does not engage platen assembly 48. Once stop pin 210 no longer engages platen assembly 48, hydraulic ram 44 moves fork 46, platen assembly 48, and first tire 260 in direction 268 toward and into riser duct 32. Back plate 50 of fork 46 engages back wall 78 of platen assembly 48 so that movement of hydraulic ram 44 in direction 268 also moves platen assembly 48 in direction 268. The charger housing 38 includes a sealing region 278 and the platen assembly 48 is positioned to lie in sealing region 278 when fork 46 supports tire 260 in riser duct 32. The platen assembly 48 acts as a valve 26 that opens and closes as platen assembly 48 moves in and out of sealing region 278 of charger housing 38. When platen assembly 48 is positioned to lie in sealing region 278, the platen assembly 48 acts as a valve that is shut to substantially prevent any flow between the riser duct 32 and the environment outside of fuel charging apparatus 30.

Because the platen assembly 48 is moved to a position to provide an obstruction to flow between riser duct 32 and the environment outside of fuel charging apparatus 30, the door 254 of door mechanism 238 may be opened. Once door 254 is opened, the carrier 236 may move second tire 262 in direction 280 toward downwardly facing fuel module delivery opening 242. The posts 250 of carrier 236 ensure that tire 262 is moved as carrier 236 is moved.

In the illustrated embodiment, the platen assembly (fuel module support cleaner 24) is moved by hydraulic ram 44 so that the platen assembly may also function as a valve. In alternative embodiments of the present invention, the fuel module support cleaner does not also have to function as a valve and may be stationary by, for example, being rigidly fixed to the charger housing or charger frame. The section of riser duct 32 that tire 260 is charged into is a "reducing atmosphere" having relatively low oxygen content and high kiln gas stream velocity. Because of the low oxygen content, tire 260 does not combust but rather degrades or pyrolyses into tiny particles 298. The particles 298 are carried upward in riser duct 32 in direction 299 to a section of riser duct 32 having a higher oxygen content where the pyrolysed particles 298 will combust.

The amount of time that fork 46 holds tire 260 in riser duct 32 may be adjusted so that any desired amount of tire is decomposed before hydraulic ram 44 pulls fork 46 back away from riser duct 32. For example, fork 46 may support tire 260 in riser duct 32 until 100% of tire 260 degrades or until 50% of tire 260 degrades so that the remaining 50% of tire 260 falls downwardly through riser duct 32.

Before hydraulic ram 44 pulls fork 46 away from riser duct 32, actuator 196 of stop device 43 moves linkage assemblies 198, 214 and rod 212 in direction 282 so that stop pin 216 is moved upwardly in direction 284 through stop pin-receiving aperture 230 formed in charger housing 38. Once stop pin 216 is advanced through stop pin-receiving aperture 230 of charger housing 38, retraction of hydraulic ram 44 in direction 286 will move fork 46 in direction 286 relative to platen assembly 48 as shown in Fig. 10.

This lost motion movement between fork 46 and platen assembly 48 permits prongs 52, 54, 56, 58, 60 to be cleaned by platen assembly 48. Platen assembly 48 includes cleaning collars 288 positioned to lie around prong-receiving apertures 86, 88, 90, 92, 94 formed in front wall 76 of platen assembly 48. As shown in Fig. 12, as prongs 52, 54, 56, 58, 60 are retracted in direction 286, residue from tire 260 on prongs 52, 54, 56, 58, 60 is scraped off of prongs 52, 54, 56, 58, 60 by cleaning collars 288. The cleaning collars 288 provide a cutting edge that scrapes or cuts the residue off of the prongs 52, 54, 56, 58, 60.

The cleaning of prongs 52, 54, 56, 58, 60 occurs in an environment that is substantially isolated from the environment outside of fuel charging apparatus 30 because platen assembly 48 acts as a valve to obstruct the flow of substances between riser duct 32 and an environment outside of fuel charging apparatus 30. The cleaning takes place in this location so that the fuel module residue on prongs 52, 54, 56, 58, 60 is still hot and is easier to remove. In addition, the residue may combust if exposed to an environment containing more oxygen than that present in the section of riser duct 32 adjacent to fuel charging apparatus 30.

Once the prongs 52, 54, 56, 58, 60 are cleaned by platen assembly 48, the stop device 43 moves stop pins 210, 216 downwardly in direction 276 so that movement of hydraulic ram 44 in direction 286 moves fork 46 and platen assembly 48 in direction 286 as shown in Fig. 13. The coupler 114 attached to prong 62 engages back wall 78 of platen assembly 48 to pull platen assembly 48 in direction 286. The amount of lost motion between platen assembly 48 and fork 46 is defined by length 287 of prong 62 of fork 46 as shown in Fig. 10. The door 254 of door mechanism 238 is closed before platen assembly

48 is removed from sealing region 278 of charger housing 38 so that the flow of substances between riser duct 32 and the environment outside of fuel charging apparatus 30 remains obstructed. The third tire 262 is on conveyor 266 and being moved toward fuel module feeder mechanism 42. Next, carrier 236 is moved in direction 290. As carrier 236 is moved in direction 290, the posts 250 of carrier 236 move through slots 258 formed in door 254 and door 254 engages tire 262 to permit carrier 236 to move in direction 290 relative to tire 262. A ratchet or other type of stop device may be used to assist door 254 in remaining in the closed position when the door 254 engages tire 262. Once carrier 236 moves far enough in direction 290, tire 262 drops through downwardly facing fuel module delivery opening 242 into charger housing 38 as shown in Fig. 7.

The fork 46 is positioned to lie in riser duct 32 only during the selected time period when fuel module 16 is supported within riser duct 32. When fuel module 16 is not supported within riser duct 32, fork 46 is retracted within charger housing 38 and somewhat protected from the high temperature environment of riser duct 32.

An alternative location of fuel charging apparatus 30 is shown in Fig. 14. Preheater/precalciner kiln 34 further includes a tertiary air duct 292 that provides oxygen to riser duct 32 and fuel charging apparatus 30 may charge fuel modules 16 into tertiary air duct 292. As a fuel module 16 is introduced into tertiary air duct 292, the fuel module 16 will immediately combust due to the relatively high concentration of oxygen and temperature in tertiary air duct 292. Yet another alternative location of fuel charging apparatus 30 is shown in Fig. 15. The preheater/precalciner kiln 34 further includes a shelf transition portion 294 positioned to lie between riser duct 32 and rotary kiln 36 and fuel charging apparatus 30 may charge fuel modules 16 into riser duct 32 directly above shelf transition portion 294.

Although the invention has been described and defined in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of the invention as described and claimed in the following claims.

Claims

CLALMS

1. A fuel charging apparatus configured to charge fuel modules through an aperture formed in a vessel, the fuel charging apparatus comprising a lost motion fuel charging mechanism having a fuel module support and a fuel module support cleaner, the fuel module support being adapted to engage and move the fuel module, and a power mechanism coupled to the fuel module support and configured to move the fuel module support relative to the fuel module support cleaner to clean the fuel module support.

2. The fuel charging apparatus of claim 1, wherein the lost motion fuel charging mechanism includes a stop, the stop is movable between a first position abutting the fuel module support cleaner to prevent the power mechanism from moving the fuel module support cleaner and a second position spaced apart from the fuel module support cleaner to permit the power mechanism to move the fuel module support cleaner.

3. The fuel charging apparatus of claim 2, wherein stop includes a stop pin and an actuator that moves the stop pin between the first and second positions.

4. The fuel charging apparatus of claim 3, further comprising a housing, the fuel module support and fuel module support cleaner being positioned in the housing, the housing including a stop pin aperture, and the stop pin is positioned within the housing in the first position.

5. The fuel charging apparatus of claim 2, wherein the stop includes first and second stop pins and an actuator that moves the first and second stop pins between the first and second positions.

6. The fuel charging apparatus of claim 5, wherein the power mechanism is configured to move the fuel module support cleaner between a retracted position and an extended position and the first stop pin abuts the fuel module support cleaner when fuel module support cleaner is in its retracted position and the second stop pin abuts the fuel module support cleaner when the fuel module support cleaner is in its extended position.

7. The fuel charging apparatus of claim 1, wherein the fuel module support includes a plurality of prongs that support a fuel module.

8. The fuel charging apparatus of claim 7, wherein the fuel module support cleaner includes a plate having prong-receiving apertures and the power mechanism moves the prongs through the prong-receiving apertures.

9. The fuel charging apparatus of claim 8, wherein the fuel module support cleaner further includes cleaning collars positioned around the prong-receiving apertures and the cleaning collars provide a cutting edge to clean the prongs as they are moved through the prong-receiving apertures.

10. The fuel charging apparatus of claim 7, wherein the fuel module support further includes a back plate coupled to the power mechanism and the prongs are connected to the back plate.

11. The fuel charging apparatus of claim 10, wherein the fuel module support cleaner includes a plate having prong-receiving apertures, at least one of the prongs includes a coupler, the power mechanism is configured to move the prongs of the fuel module support through the prong-receiving apertures of the fuel module support cleaner in a first direction until the back plate of the fuel module support abuts the plate of the fuel module support cleaner and in a second direction until the coupler of at least one of the prongs abuts the plate of the fuel module support cleaner.

12. The fuel charging apparatus of claim 1, wherein the housing includes spaced-apart guide rails that define guide slots and the fuel module support includes guide tabs that are positioned in the guide slots and travel through the guide slots as the power mechanism moves the fuel module support.

13. The fuel charging apparatus of claim 12, wherein the fuel module support cleaner includes guide tabs that are positioned in the guide slots and travel through the guide slots as the power mechanism moves the fuel module support cleaner.

14. The fuel charging apparatus of claim 13, wherein the guide tabs of the fuel module support and fuel module support cleaner couple the fuel module support and fuel module support cleaner to the housing.

15. A fuel charging apparatus configured to charge fuel modules through an aperture formed in a vessel, the fuel charging apparatus comprising a housing having a vessel opening in communication with the vessel and a fuel module-receiving aperture, a fuel module support positioned in the housing, the fuel module support being adapted to engage and move the fuel module through the housing and into the vessel, a power mechanism coupled to the fuel module support and configured to move the fuel module support through the housing, a fuel module feeder coupled to the housing, the fuel module feeder including a fuel module delivery opening in communication with the fuel module- receiving aperture in the housing, the fuel module feeder including a door movable between an opened position and a closed position and a carrier that moves the fuel module through the door when the door is in the opened position and deposits the fuel module into the fuel module delivery opening, and a valve positioned in the housing, the valve being movable between a first position wherein the valve substantially blocks the flow of ambient air from the housing into the vessel and a second position, and the valve coordinates with the door of the fuel module feeder to substantially block flow of ambient air into the vessel through the fuel module feeder and housing.

16. The fuel charging apparatus of claim 15, wherein the housing includes a sealing region positioned between the vessel opening and fuel module- receiving aperture and the power mechanism moves the valve between the first and second positions.

17. The fuel charging apparatus of claim 15, wherein the valve is a fuel module support cleaner, the power mechanism moves the fuel module support relative to the fuel module support cleaner to clean the fuel module support.

18. The fuel charging apparatus of claim 17, wherein the power mechanism moves the fuel module support relative to the fuel module support cleaner to clean the fuel module support when the fuel module support cleaner is in the first position substantially blocking the flow of ambient air from the housing into the vessel.

19. The fuel charging apparatus of claim 17, wherein the fuel module support cleaner includes spaced-apart front and back walls, the front wall is positioned between the vessel opening and the back wall, and the front wall of the fuel module support cleaner contacts the fuel module support to clean the fuel module support.

20. The fuel charging apparatus of claim 17, further comprising a stop movable between a first position abutting the fuel module support cleaner to prevent the power mechanism from moving the fuel support cleaner and a second position spaced apart from the fuel module support cleaner to permit the power mechanism to move the fuel module support cleaner.

21. The fuel charging apparatus of claim 16, wherein the valve is a platen assembly.

22. The fuel charging apparatus of claim 15, wherein the door includes slots and the carrier includes posts, the posts maintain the fuel module on the carrier when the carrier moves the fuel module toward the fuel module delivery opening and the door is in the open position, and the posts pass through the slots when the carrier moves away from the fuel module delivery opening and the door is in the closed position.